Viscosity reduction type concrete hyperdispersant and preparation method thereof

Abstract

The invention relates to the technical field of hyperdispersants, in particular to a viscosity reduction type concrete hyperdispersant which is prepared by carrying out addition polymerization on three different types of monomers containing alpha-double bonds, the monomer 1 is an ester macromonomer, the monomer 2 is an ether macromonomer, and the monomer 3 is a functional small monomer; the invention also discloses a preparation method of the viscosity reduction type concrete hyperdispersant. According to the viscosity reduction type concrete hyperdispersant and the preparation method thereof, part of hydrophobic chain segments are introduced to a polycarboxylic acid main chain, and a side chain is modified, so that the dispersing performance of a polycarboxylic acid type high-performance water reducer is improved, the viscosity of concrete under the condition of a low water cement ratio can be effectively reduced, and the viscosity reduction type concrete hyperdispersant has a good application prospect. The dispersing effect of the polycarboxylic acid high-performance water reducing agent is effectively enhanced, and the application range of the existing product is widened.

Description

Technical Field

[0001] The present invention relates to the technical field of super-dispersants, in particular to a viscosity-reducing concrete super-dispersant and a preparation method thereof. Background Art

[0002] As the main component of the third-generation concrete admixture, concrete super-dispersants are mostly prepared by addition polymerization of polyether macromonomers, ester macromonomers and functional small monomers.

[0003] While obtaining a relatively high water-reducing rate, the concrete super-dispersant itself has relatively prominent disadvantages of dosage sensitivity and high viscosity of concrete under the condition of low water-cement ratio. Especially when preparing high-strength and ultra-high-strength concrete products, traditional polycarboxylate high-performance water-reducing agents cannot ensure the workability of concrete under the condition of low water-cement ratio. Summary of the Invention

[0004] In order to solve the above technical deficiencies, the present invention provides a viscosity-reducing concrete super-dispersant and a preparation method thereof, which can effectively enhance the dispersion effect of polycarboxylate-based high-performance water-reducing agents and reduce the viscosity of concrete under the condition of low water-cement ratio.

[0005] The present invention discloses a viscosity-reducing concrete super-dispersant, and its molecular formula is as follows:

[0006]

[0007] It is obtained by addition polymerization of three different types of monomers containing α-double bonds, and is shown as Formula 1:

[0008]

[0009] In the formula, monomer 1 is the general formula of an ester macromonomer, monomer 2 is the general formula of an ether macromonomer, and monomer 3 is the general formula of a functional small monomer; A, B, and C are the average polymerization degrees of the three different types of monomers respectively; A, B, and C are only for the convenience of representing this equation, and A, B, and C are the equivalent molar ratios of monomers 1, 2, and 3, and can be obtained by dividing the amount of each monomer used during polymerization by the sum of the average relative molecular masses of each monomer.

[0010] Monomer 1: R 1 is a substituent group, and is any one of H, CH 3 , CH 3 CH 2 ; j and k are the addition coefficients of ethylene oxide and propylene oxide respectively, j = 2 - 60, k = 0 - 5, ethylene oxide and propylene oxide are block polymerized, and the number of block times is 1 - 5 times or random polymerization; X is the end-capping group of monomer 1, and is any one of H, K + , Na + , CH 3 ;

[0011] Monomer 2: R 2 , R 3 is a substituent, R 2 is H or CH 3 , R 3 is CH 2 , (CH 2 ) 2 , (CH 2 ) 6 , O(CH 2 ) 2 , O(CH 2 ) 2 O(CH 2 ) 2 , O(CH 2 ) 4 , (CH 2 ) 3 CH(CH 3 )(CH 2 ) 2 Any one of them; h and i are the addition coefficients of ethylene oxide and propylene oxide respectively, h = 5 - 150, k = 0 - 5, ethylene oxide and propylene oxide are block polymerized, the block polymerization times are 1 - 5 times or randomly polymerized, Y is the end-capping group of monomer 2, and is any one of H, K + , Na + Any one of them;

[0012] Monomer 3: R 4 is a straight-chain, branched-chain, heterocyclic, or salt-forming substituent with 1 - 20 carbon atoms.

[0013] Monomer 3 is any one of the following formulas, Formula 2: Formula 3: Formula 4: Formula 5: Formula 6: Formula 7: Formula 8: Formula 9: Formula 10:

[0014] Formula 11: Formula 12: Formula 13:

[0015]

[0016] Formula 14:

[0017] A preparation method of a viscosity-reducing type concrete super-dispersant, using aqueous solution polymerization:

[0018] Monomer 1 is 5 - 10 parts, monomer 2 is 20 - 40 parts, monomer 3 is 5 - 20 parts, and deionized water is 35 - 45 parts; the reaction is co-catalyzed by an initiator, a reducing agent, and a promoter, and a chain transfer agent is added to control the polymerization reaction process and adjust the average molecular weight of the final target product, and then neutralized with a 30 - 50% concentration of aqueous NaOH solution or triethanolamine;

[0019] The initiator is selected from one or a mixture of hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, potassium permanganate, and the initiator is 0.4 - 1% of the total amount of polymerization monomers;

[0020] The reducing agent is selected from one or a mixture of ascorbic acid, sodium formaldehyde sulfoxylate, oxalic acid, sodium nitrite, sodium bisulfite, sodium metabisulfite, ferrous sulfate, and the reducing agent is 0.1 - 0.3% of the total amount of polymerization monomers;

[0021] The chain transfer agent is selected from one or a mixture of mercaptoacetic acid, mercaptopropionic acid, mercaptoethanol, sodium methallylsulfonate, sodium hypophosphite, and the chain transfer agent is 0.3 - 0.6% of the total amount of polymerization monomers;

[0022] The promoter is selected from one or a mixture of polyethylene glycol with an average molecular weight of 200 - 400, ethyl acetate, N-methylpyrrolidone, crown ether, dimethyl sulfoxide, and the promoter is 0.1 - 5% of the total amount of polymerization monomers;

[0023] The synthesis temperature is 0 - 80 °C, the reaction time is 1 - 6 h, and the aging time is 1 - 2 h;

[0024] The molar ratio of the solid content of the neutralizing alkali solution to the acid amount in the monomer is 0.6 - 1.1:1.

[0025] When hydrogen peroxide is selected as the initiator, the synthesis temperature is 10 - 40 °C; when ammonium persulfate or potassium persulfate or sodium persulfate is selected as the initiator, the synthesis temperature is 40 - 60 °C.

[0026] A viscosity-reducing type concrete superdispersant and its preparation method obtained by the present invention can improve the dispersion performance of polycarboxylate-based high-performance water reducers by introducing partial hydrophobic chain segments on the polycarboxylic acid main chain and modifying the side chains, can effectively reduce the viscosity of concrete under low water-cement ratio conditions, effectively enhance the dispersion effect of polycarboxylate-based high-performance water reducers, and broaden the application range of existing products.

[0027] A viscosity-reducing type concrete superdispersant according to the present invention, the main chain of which mainly provides strongly polar carboxylic acid groups, or sulfate groups, or sulfonic acid groups by monomer 3, so as to combine with calcium ions on the surface of cement particles to complete the anchoring of cement particles, as shown in Formula 2, Formula 3, Formula 11, and Formula 12. Monomer 3 containing an amide group has an opposite ionic charge to that contained in the clay lamellar structure, which can prevent the alkoxylated long side chains of monomer 1 and monomer 2 from inserting into the clay lamellar structure, thereby losing the dispersing effect on cement particles, as shown in Formula 9 and Formula 12.

[0028] The alkoxylated long side chains of monomer 1 and monomer 2 usually have an average molecular weight of about 800 - 3000. Conventional commercially available varieties are mostly obtained by adding ethylene oxide, which can form hydrogen bonds with the hydration film on the surface layer of cement particles and, through steric hindrance, prevent cement particles from approaching each other, thus realizing the dispersing effect on cement particles.

[0029] For the alkoxylated tail end of monomer 1 and monomer 2 of the present invention, propylene oxide with a polymerization degree of 0 - 3 is selected. On the one hand, it increases the hydrophobicity of the alkoxylated side chain, enhancing the dispersing ability of cement particles. On the other hand, the local structure of propylene oxide can play a certain defoaming and foam stabilizing role, which is beneficial to improving the durability of concrete products.

[0030] Monomer 2 can be obtained by first mixing several different initiators and then adding ethylene oxide and propylene oxide, and the product is used as a raw material to participate in the synthesis of the viscosity-reducing type concrete superdispersant. It can also be obtained by adding ethylene oxide and propylene oxide to each different-structured initiator respectively, and then mixing the products and using them as raw materials to participate in the synthesis of the viscosity-reducing type concrete superdispersant.

[0031] The modified viscosity-reducing type concrete superdispersant has good dispersing and viscosity-reducing effects on cement paste. This product can also be used as a component of a cement grinding aid and is used in combination with triethanolamine, triisopropanolamine, etc. Detailed implementation mode

[0032] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following, in combination with preferred embodiments, details the specific implementation mode, structure, characteristics, and their effects according to the present invention as follows.

[0033] Example 1:

[0034] The present invention discloses a preparation method of a viscosity-reducing type concrete superdispersant,

[0035] Monomer 1 is selected as the product obtained by esterifying with acrylic acid, with a methoxy end group, a polyethylene oxide polymerization degree of 35 - 38, and a polypropylene oxide polymerization degree of 2, as shown in Formula 15:

[0036]

[0037] Monomer 2 is a mixture of a C4 monomer, a C5 tail monomer capped with 1 mol of propylene oxide, and a C6 tail monomer capped with 2 mol of propylene oxide, and the mass ratio of the three is 50:40:10.

[0038] Monomer 3 is selected as Formula 2: Formula 6:

[0039] Formula 13: The mixture of the three has a mass ratio of 40-50:30-40:10-15.

[0040] The mass ratio of the three can be adjusted within the above ratio range. In actual use, the appropriate ratio can be adjusted according to different reference cements or different tests. Of course, for example: 45:35:15, or 40:40:10, etc.

[0041] Hydrogen peroxide is selected as the initiator, ascorbic acid as the reducing agent, and mercaptopropionic acid as the chain transfer agent.

[0042] Ethyl acetate is selected as the co-catalyst.

[0043] The reaction temperature is room temperature, preferably a value within the range of 15-40 °C, the reaction time is 3 h, and the aging time is 1 h.

[0044] In the total synthesis material system, there are 5 parts of monomer 1; 35 parts of monomer 2; and 15 parts of monomer 3. The amounts of the initiator, reducing agent, chain transfer agent, and co-catalyst are 0.6%, 0.25%, 0.4%, and 1% of the total amounts of monomer 1, monomer 2, and monomer 3, respectively.

[0045] The reaction process is as shown in Formula 16:

[0046]

[0047] The obtained product is denoted as m-PCE-1, which is a viscosity-reducing type concrete superplasticizer.

[0048] m-PCE-1 can be used in compound with a conventional polycarboxylate-based concrete water reducer, and the proportion of m-PCE-1 in the mixture is 30-50%; it can also be used alone as a component of the concrete water reducer, and the recommended dosages of both are 0.1-0.5% of the concrete binder.

[0049] Example 2:

[0050] The present invention discloses a preparation method of a viscosity-reducing type concrete superplasticizer,

[0051] Monomer 1 is selected as the product obtained by esterifying methoxy-capped, polyoxyethylene with a polymerization degree of 35-38, polyoxypropylene with a polymerization degree of 2, and methacrylic acid, as shown in Formula 17:

[0052]

[0053] For monomer 2, the initiators used are those with 4, 5, and 8 carbon atoms, and the mixing ratio of the three is 30:60:10. The degree of polymerization of the mixture with ethylene oxide is 50 - 60, and it is capped with 2 mol of propylene oxide.

[0054] For monomer 3, a mixture of Formula 3, Formula 4, and Formula 14 is used, and the mass ratio of the three is 40 - 50:30 - 40:10 - 20. According to actual requirements, the mass ratio of the three can be 50:30:20.

[0055] Hydrogen peroxide is selected as the initiator, sodium formaldehyde bisulfite as the reducing agent, mercaptopropionic acid as the chain transfer agent, and 18 - crown - 6 as the co - catalyst.

[0056] The reaction temperature is room temperature, preferably a value within the range of 15 - 40 °C, such as 20 °C, 30 °C, etc., and it can fluctuate up and down. The reaction time is 3 h, and the curing time is 1 h.

[0057] In the total synthesis material system, there are 8 parts of monomer 1; 40 parts of monomer 2; and 15 parts of monomer 3. The dosages of the initiator, reducing agent, chain transfer agent, and co - catalyst are 0.65%, 0.25%, 0.35%, and 2.5% of the total amounts of monomer 1, monomer 2, and monomer 3, respectively.

[0058] The reaction process is as shown in Formula 18:

[0059]

[0060] The obtained product is denoted as m - PCE - 2, that is, a viscosity - reducing type concrete superplasticizer.

[0061] m - PCE - 2 can be compounded with conventional polycarboxylate - based concrete water - reducing agents for use. After mixing, the proportion of m - PCE - 2 is 30 - 50%; it can also be used alone as a component of concrete water - reducing agents, and the recommended dosage of both is 0.1 - 0.5% of the concrete binder. It can also be used as a water - reducing aid for ceramics or as a component of a cement grinding aid.

[0062] Example 3:

[0063] The present invention discloses a preparation method of a viscosity - reducing type concrete superplasticizer,

[0064] For monomer 1, a product obtained by esterifying a polyoxyethylene with a degree of polymerization of 35 - 38 and a polyoxypropylene with a degree of polymerization of 2, which is capped with methoxy, is as shown in Formula 19:

[0065]

[0066] Monomer 2 is a mixture of a C4 monomer, a C5 monomer capped with 1 mol of propylene oxide at the tail, and a C6 monomer capped with 2 mol of propylene oxide at the tail, and the mass ratio of the three is 50:40:10.

[0067] Monomer 3 is selected as Formula 2: Formula 9:

[0068] Formula 14: The mixture of the three has a mass ratio of 40-50: 30-40: 10-15. According to actual requirements, the mass ratio of the three can be 45:35:10.

[0069] Hydrogen peroxide is selected as the initiator, ascorbic acid as the reducing agent, and mercaptopropionic acid as the chain transfer agent.

[0070] Ethyl acetate is selected as the co-catalyst.

[0071] The reaction temperature is room temperature, preferably a value in the range of 15-40 °C, the reaction time is 3 h, and the aging time is 2 h.

[0072] In the total synthesis material system, there are 5 parts of monomer 1; 35 parts of monomer 2; 15 parts of monomer 3. The amounts of the initiator, reducing agent, chain transfer agent, and co-catalyst are 0.6%, 0.25%, 0.4%, and 2% of the total amounts of monomer 1, monomer 2, and monomer 3, respectively.

[0073] The reaction process is as shown in Formula 20:

[0074]

[0075] The obtained product is denoted as m-PCE-3, that is, a viscosity-reducing type concrete superplasticizer.

[0076] m-PCE-3 can be used in compound with a conventional polycarboxylate-based concrete water reducer, and the proportion of m-PCE-3 after mixing is 30-50%; it can also be used alone as a component of a concrete water reducer, and the recommended dosages of both are 0.1-0.5% of the concrete binder, and it can also be used as a cement grinding aid.

[0077] As described above, it is only a preferred embodiment of the present invention, and it does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content within the scope of the technical solution of the present invention to obtain equivalent embodiments with equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simplified modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A viscosity-reducing concrete superdispersant, characterized in that: Its molecular formula is as follows: It is obtained by addition polymerization of three different types of monomers containing α-double bonds, as shown in Formula 1: Wherein, monomer 1 is an ester macromonomer, monomer 2 is an ether macromonomer, and monomer 3 is a functional small monomer; A, B, and C are the average polymerization degrees of three different types of monomers, respectively; Monomer 1: R1 is a substituent group, which is any one of H, CH3, and CH3CH2. j and k are the addition coefficients of ethylene oxide and propylene oxide, respectively, j=2-60, k=0-5. Ethylene oxide and propylene oxide are block polymerization with 1-5 blocks or random polymerization. X is the end-capping group of monomer 1, which is H, K + 、Na + , CH3; Monomer 2: R2 and R3 are substituents, R2 is H or CH3, R3 is any one of CH2, (CH2)2, (CH2)6, O(CH2)2, O(CH2)2O(CH2)2, O(CH2)4, (CH2)3CH(CH3)(CH2)2; h and i are the addition coefficients of ethylene oxide and propylene oxide, respectively, h=5-150, k=0-5, ethylene oxide and propylene oxide are block polymerization, the number of blocks is 1-5 times or it is random polymerization, Y is the end-capping group of monomer 2, which is H, K + 、Na + Any of the following: Monomer 3: R4 is a normal, isomeric, heterocyclic, or salt-forming substituent having 1 to 20 carbon atoms.

2. The viscosity-reducing concrete superdispersant according to claim 1, characterized in that: Monomer 3 is any one of the following formulas, Formula 2: Formula 3: Formula 4: Formula 5: Formula 6: Formula 7: Formula 8: Formula 9: Formula 10: Formula 11: Formula 12: Formula 13: Formula 14:

3. A method for preparing the viscosity-reducing concrete superdispersant as claimed in claim 1, characterized in that: Using aqueous solution polymerization: The monomer 1 is 5-10 parts, the monomer 2 is 20-40 parts, the monomer 3 is 5-20 parts, and the deionized water is 35-45 parts; the reaction is catalyzed by an initiator, a reducing agent, and a co-catalyst, a chain transfer agent is added to control the polymerization process and adjust the average molecular weight of the final target product, and then a 30-50% concentration NaOH aqueous solution or triethanolamine is used for neutralization; The initiator is selected from one or a mixture of hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, potassium permanganate, and the initiator is 0.4-1% of the total amount of the polymerization monomers; The reducing agent is one or a mixture of ascorbic acid, sodium bisulfite formaldehyde, oxalic acid, sodium nitrite, sodium bisulfite, sodium pyrosulfite, and ferrous sulfate, and the reducing agent is 0.1-0.3% of the total amount of the polymerized monomers; The chain transfer agent is one or a mixture of mercaptoacetic acid, mercaptopropionic acid, mercaptoethanol, sodium methyl propylene sulfonate, and sodium hypophosphite, and the chain transfer agent is 0.3-0.6% of the total amount of the polymerization monomers; The co-catalyst is one or a mixture of polyethylene glycol, ethyl acetate, N-methylpyrrolidone, crown ether, and dimethyl sulfoxide with an average molecular weight of 200 to 400, and the co-catalyst is 0.1 to 5% of the total amount of the polymerization monomers; The synthesis temperature is 0-80°C, the reaction time is 1-6 hours, and the aging time is 1-2 hours; The molar ratio of the solid content of the neutralizing alkali solution to the acid content of the monomer is 0.6-1.1:

1.

4. The method for preparing a viscosity-reducing concrete superdispersant according to claim 3, characterized in that: When hydrogen peroxide is selected as the initiator, the synthesis temperature is 10-40°C; when ammonium persulfate, potassium persulfate or sodium persulfate is selected as the initiator, the synthesis temperature is 40-60°C.

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