(2) background technology
Cement water reducing agent is divided into three big series, the one, sulfonated lignin water reducer usually both at home and abroad at present; The 2nd, the aromatic sulfonated polymer water reducer; The 3rd, polycarboxylic acids dehydragent.But a spot of other kind is also arranged, as trimeric cyanamide system and sulfamate etc.
Lignosulfonic acid salt water reducer retardation phenomenon is more serious, and its raw material is from industrial effluent.The performance of xylogen and the influence of toxic and harmful substance are difficult to control, and its water-reducing rate is only about 8%-13%, and present domestic consumption is little, but because it cheaply still has use.
Characteristics such as naphthalene water reducer has mature production technology, not bleed, slow setting, cement adaptability be not good, but slump-loss is bigger, be difficult to satisfy the construction requirement of actual engineering, generally need by compound use, and many composite prod quality instabilities are arranged, influence concrete hardness and the weather resistance of condensing, this product uses formaldehyde, the vitriol oil to be prepared from mostly in addition, the preparation process environmental pollution is serious, and also be subjected to the influence of raw naphthalene material resource, domestic naphthalene resource can't satisfy the chemical engineering industry demand.
Its diminishing enhancement of melamine system water reducer slightly is better than naphthalene water reducer, but is higher than naphthalene system on usage quantity and price.Owing to being that the liquid use is restricted, the storage time is short in addition, slump-loss is big, concrete is clamminess, and practical application is less.
Sulfamate also is a kind of high efficiency water reducing agent, and synthesis technique is simple than naphthalene system, diminishing efficient height, and slump-loss is little, but volume and cement are all compared sensitivity, and retarding effect is obvious, and main at present and naphthalene is compound use.
Polycarboxylic acids dehydragent has water-reducing rate height (more than 30%), volume is few, function of slump protection good, later strength is big, amount of air entrainment and slow setting are comparatively moderate, suitable preparation high workability, self-compacting concrete and the synthetic formaldehyde that do not use, to the little excellent properties that waits of environmental influence, become brand-new high-performance water reducing agent, be considered to the representative kind of third generation efficient cement water reducing agent.
Poly carboxylic acid series water reducer is high-strength high-flowing concrete, the most important composition material of high volume fly ash concrete, so its prospect will be more and more wide.But because cost and technical feature problem, the poly carboxylic acid series water reducer of domestic development does not nearly all reach the practicability stage.Relevant paper from domestic periodical and journal, domestic research to the poly carboxylic acid series water reducer product only is in the laboratory development stage, can be also very limited for the starting material that synthesizing polycarboxylic acid dehydragent is selected, choosing production technique, reduce cost, improve many aspects such as performance from the water reducer starting material, also only is starting.Some laboratory synthetic water reducers, its over-all properties is not fine, also has sizable gap from industrial applications.
Japan is that research and application poly carboxylic acid series water reducer at most also are the most successful countries, the acrylic acid graft copolymer cement water reducing agent volume of its research was less than 0.1% o'clock, can be reduced to concrete water cement ratio about 0.20, the preparation slump is that 250mm, intensity are that the strong concrete of 100MPa is used for Prestressed Concrete Bridges, and concrete kept good operation in 2 hours.Japan is few about prepare the road quantity that cement water reducing agent gets with maleic anhydride, and technology is all complicated.
Some technical information were in this respect also disclosed in the Chinese patent application, as number of patent application be 200410027709.7, name is called " a kind of preparation method of polyether grafting polyocarboxy acid type cement water reducing agent "; And for example application number is 200510019876.1, name is called " a kind of maleic anhydride series concrete water-reducing agent and preparation method ".Particularly disclose in one application of back " is in the method for feedstock production cement water reducing agent with maleic anhydride; be earlier to carry out esterification with maleic anhydride and methoxy poly (ethylene glycol); being catalyzer to benzene methanesulfonic acid; cuprous chloride and Resorcinol are stopper; toluene is solvent; react and get esterification products more than 10 hours, carry out polyreaction with the rare sodium sulfonate of 2-the third rare acid amides-2 methyl-prop after removing solvent toluene, with the ammonium persulphate is initiator, mercaptoethanol is a chain-transfer agent, 95 ℃ of reactions down, obtain water reducer solution." from the above, prepare the method for cement water reducing agent with maleic anhydride, need in esterification, add stopper and solvent, reaction finishes the back and separates the difficulty of purifying, and technology is longer than complexity and reaction times.
(3) summary of the invention
The objective of the invention is with maleic anhydride etc. to develop a kind of polyocarboxy acid type cement water reducing agent as cheap raw material, this method synthesis condition gentleness, equipment requirements is low, and technology is simple.
The present invention has prepared the polyocarboxy acid type water reducer that has long side chain by the method for first esterification post polymerization, thereby has realized purpose of the present invention.Concrete technical scheme is as follows:
(1) esterification: with solid acid
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2Be catalyzer, at 80 ℃~90 ℃, the esterification under the reduced pressure 4 hours is removed solid acid by polyoxyethylene glycol and maleic anhydride, obtain polyoxyethylene glycol esterified object of maleic anhydride (PEM) and the mixture that remains maleic anhydride, the relative molecular weight of described polyoxyethylene glycol is 1000;
(2) copolyreaction: with the ammonium persulphate is initiator, with the mixture of the polyoxyethylene glycol esterified object of maleic anhydride (PEM) of step (1) gained and residue maleic anhydride and vinylformic acid, methylpropene sodium sulfonate 85 ± 5 ℃ of following copolymerization 3~5 hours, the cooling back adds the sodium hydroxide solution neutralization, regulating pH value is 7~8, obtains described water reducer.
The proportioning of each reactant is as follows in the above-mentioned steps:
Polyoxyethylene glycol (PEG): maleic anhydride (MA)=1:3~4 (mol ratio); Catalyzer is a solid acid
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2, consumption is the 6wt%~10wt% of polyoxyethylene glycol+maleic anhydride total amount; Vinylformic acid (AA): polyoxyethylene glycol esterified object of maleic anhydride (PEM) and the mixture that remains maleic anhydride: methylpropene sodium sulfonate (MAS)=1~1.5:3.8:1.3 (weight percent); The initiator ammonium persulfate consumption is 8~13wt% of reaction-ure mixture.
Esterification described in the step (1) is under reduced pressure carried out, and vacuum tightness is 0.2~0.4 normal atmosphere.
Advantage of the present invention
1. the reaction conditions gentleness is low for equipment requirements, and in esterification and copolyreaction, temperature of reaction all is no more than 90 ℃, and esterification is used solid acid
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2, not strong to equipment corrosion, and can reuse.
2. in esterification, need not add stopper, and catalyzer removes easily, to the not influence of next step polyreaction.
3. use the polyoxyethylene glycol of cheap maleic anhydride industrial goods and two hydroxyls in the raw material, helped reducing the cost of polycarboxylate water-reducer.
4. can react by each step of control, thereby the control product structure reaches the product performance requirement.
5. technology is relatively simple and the reaction times is short.
(4) embodiment
Embodiment 1:
With molecular weight is 1000 polyoxyethylene glycol 60.0g, maleic anhydride 18.0g, solid acid
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26.3g put into reaction vessel, heating, stirring dissolves reactant fully, vacuumizes 0.2 normal atmosphere, maintains the temperature at 85 ± 5 ℃, reacts 4 hours, generates polyoxyethylene glycol esterified object of maleic anhydride (PEM).PEM40.0g and methylpropene sodium sulfonate 18.0g are put into reaction vessel, add 80.0g water, heating, stir reactant is dissolved fully, dropwise addition of acrylic acid 13.0g on one side drips mass percent on one side and is 8% ammonium persulfate solution 82.8g, controls rate of addition, about 100 minutes, drip off, maintain the temperature at 85 ± 5 ℃, reacted 4 hours, add the sodium hydroxide neutralization after the cooling again, regulate PH=7~8, finally obtain polycarboxylic acid series high-performance cement water reducing agent of the present invention.
Embodiment 2:
With molecular weight is 1000 polyoxyethylene glycol 60.0g, maleic anhydride 24.0g, solid acid
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26.3g put into reaction vessel, heating, stirring dissolves reactant fully, vacuumizes 0.2 normal atmosphere, maintains the temperature at 85 ± 5 ℃, reacts 4 hours, generates polyoxyethylene glycol esterified object of maleic anhydride (PEM).PEM40.0g and methylpropene sodium sulfonate 18.0g are put into reaction vessel, add 80.0g water, heating, stir reactant is dissolved fully, dropwise addition of acrylic acid 13.0g on one side drips mass percent on one side and is 8% ammonium persulfate solution 82.8g, controls rate of addition, about 100 minutes, drip off, maintain the temperature at 85 ± 5 ℃, reacted 4 hours, add the sodium hydroxide neutralization after the cooling again, regulate PH=7~8, finally obtain polycarboxylic acid series high-performance cement water reducing agent of the present invention.
Embodiment 3:
With molecular weight is 1000 polyoxyethylene glycol 60.0g, maleic anhydride 18.0g, solid acid
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24.7g put into reaction vessel, heating, stirring dissolves reactant fully, vacuumizes 0.3 normal atmosphere, maintains the temperature at 85 ± 5 ℃, reacts 4 hours, generates polyoxyethylene glycol esterified object of maleic anhydride (PEM).PEM40.0g and methylpropene sodium sulfonate 18.0g are put into reaction vessel, add 80.0g water, heating, stir reactant is dissolved fully, dropwise addition of acrylic acid 13.0g on one side drips mass percent on one side and is 8% ammonium persulfate solution 82.8g, controls rate of addition, about 100 minutes, drip off, maintain the temperature at 85 ± 5 ℃, reacted 4 hours, add the sodium hydroxide neutralization after the cooling again, regulate PH=7~8, finally obtain polycarboxylic acid series high-performance cement water reducing agent of the present invention.
Embodiment 4:
With molecular weight is 1000 polyoxyethylene glycol 60.0g, maleic anhydride 18.0g, solid acid
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27.8g put into reaction vessel, heating, stirring dissolves reactant fully, vacuumizes 0.4 normal atmosphere, maintains the temperature at 85 ± 5 ℃, reacts 3 hours, generates polyoxyethylene glycol esterified object of maleic anhydride (PEM).PEM40.0g and methylpropene sodium sulfonate 18.0g are put into reaction vessel, add 80.0g water, heating, stir reactant is dissolved fully, dropwise addition of acrylic acid 13.0g on one side drips mass percent on one side and is 8% ammonium persulfate solution 82.8g, controls rate of addition, about 100 minutes, drip off, maintain the temperature at 85 ± 5 ℃, reacted 4 hours, add the sodium hydroxide neutralization after the cooling again, regulate PH=7~8, finally obtain polycarboxylic acid series high-performance cement water reducing agent of the present invention.
Embodiment 5:
With molecular weight is 1000 polyoxyethylene glycol 60.0g, maleic anhydride 18.0g, solid acid
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26.3g put into reaction vessel, heating, stirring dissolves reactant fully, vacuumizes 0.2 normal atmosphere, maintains the temperature at 85 ± 5 ℃, reacts 4 hours, generates polyoxyethylene glycol esterified object of maleic anhydride (PEM).PEM40.0g and methylpropene sodium sulfonate 18.0g are put into reaction vessel, add 80.0g water, heating, stir reactant is dissolved fully, dropwise addition of acrylic acid 10.4g on one side drips mass percent on one side and is 8% ammonium persulfate solution 82.8g, controls rate of addition, about 100 minutes, drip off, maintain the temperature at 85 ± 5 ℃, reacted 4 hours, add the sodium hydroxide neutralization after the cooling again, regulate PH=7~8, finally obtain polycarboxylic acid series high-performance cement water reducing agent of the present invention.
Embodiment 6:
With molecular weight is 1000 polyoxyethylene glycol 60.0g, maleic anhydride 18.0g, solid acid
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26.3g put into reaction vessel, heating, stirring dissolves reactant fully, vacuumizes 0.2 normal atmosphere, maintains the temperature at 85 ± 5 ℃, reacts 4 hours, generates polyoxyethylene glycol esterified object of maleic anhydride (PEM).PEM40.0g and methylpropene sodium sulfonate 18.0g are put into reaction vessel, add 80.0g water, heating, stir reactant is dissolved fully, dropwise addition of acrylic acid 15.6g on one side drips mass percent on one side and is 8% ammonium persulfate solution 82.8g, controls rate of addition, about 100 minutes, drip off, maintain the temperature at 85 ± 5 ℃, reacted 4 hours, add the sodium hydroxide neutralization after the cooling again, regulate PH=7~8, finally obtain polycarboxylic acid series high-performance cement water reducing agent of the present invention.
Embodiment 7:
With molecular weight is 1000 polyoxyethylene glycol 60.0g, maleic anhydride 18.0g, solid acid
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26.3g put into reaction vessel, heating, stirring dissolves reactant fully, vacuumizes 0.2 normal atmosphere, maintains the temperature at 85 ± 5 ℃, reacts 4 hours, generates polyoxyethylene glycol esterified object of maleic anhydride (PEM).PEM40.0g and methylpropene sodium sulfonate 18.0g are put into reaction vessel, add 115.0g water, heating, stir reactant is dissolved fully, dropwise addition of acrylic acid 13.0g on one side drips mass percent on one side and is 8% ammonium persulfate solution 44.4g, controls rate of addition, about 100 minutes, drip off, maintain the temperature at 85 ± 5 ℃, reacted 4 hours, add the sodium hydroxide neutralization after the cooling again, regulate PH=7~8, finally obtain polycarboxylic acid series high-performance cement water reducing agent of the present invention.
Embodiment 8:
With molecular weight is 1000 polyoxyethylene glycol 60.0g, maleic anhydride 18.0g, solid acid
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26.3g put into reaction vessel, heating, stirring dissolves reactant fully, vacuumizes 0.2 normal atmosphere, maintains the temperature at 85 ± 5 ℃, reacts 4 hours, generates polyoxyethylene glycol esterified object of maleic anhydride (PEM).PEM40.0g and methylpropene sodium sulfonate 18.0g are put into reaction vessel, add 40.0g water, heating, stir reactant is dissolved fully, dropwise addition of acrylic acid 13.0g on one side drips mass percent on one side and is 8% ammonium persulfate solution 126.2g, controls rate of addition, about 100 minutes, drip off, maintain the temperature at 85 ± 5 ℃, reacted 4 hours, add the sodium hydroxide neutralization after the cooling again, regulate PH=7~8, finally obtain polycarboxylic acid series high-performance cement water reducing agent of the present invention.
Embodiment 9:
By embodiment 1 to embodiment 8 prepared cement water reducing agent, solid content all is adjusted to 30%, carrying out cement according to the water reducer of GB/T8077-2000 pair gained tests degree of mobilization only, volume is 0.4wt% (with respect to a cement consumption), water reducer according to GB/T8076-1997 pair gained carries out the concrete water-reducing ratio test, volume is 0.8wt% (with respect to a cement consumption), observed value such as following table:
Embodiment |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
Degree of mobilization (mm) |
255 |
240 |
245 |
242 |
240 |
242 |
250 |
246 |
Water-reducing rate (%) |
32 |
28 |
30 |
31 |
30 |
28 |
31 |
30 |
The 3 days ultimate compression strength of concrete test block that is mixed with water reducer of the present invention improves greater than 45%, 7 day ultimate compression strength and improves ultimate compression strength raising 40% in 40%, 28 day.