CN100340518C - Process for preparing poly carboxylic acid modified fatty water-reducing agent - Google Patents

Abstract

The present invention discloses a method for preparing poly carboxylic acid modified fatty water reducing agent, which comprises that poly carboxylic acid modifying agent is prepared and further reacts with water, 20 to 30 weight portions of sodium hydroxide, sodium hydrogen sulfite, propanone and formaldehyde solution to obtain the product. The water reducing agent prepared by the present invention has the advantages of high water reducing rate, stable product performance, no delamination for long-term storage, no sedimentation, no crystallization in winter, etc. The method is simple and easy for industrialization production.

Description

The preparation method of poly carboxylic acid modified fatty water-reducing agent

Technical field:

The present invention relates to a kind of production method of water reducer.

Background technology:

Along with developing rapidly of construction industry and hydro project, to the constantly new requirement of proposition of performance of concrete each side.Normal concrete is difficult to satisfy new construction process requirement.Many countries admixture as concrete the 5th kind of constituent materials and widespread use.Water reducer is the admixture kind of consumption maximum in the concrete, can be divided into ordinary water-reducing agent and high efficiency water reducing agent by its water-reducing effect.Along with the raising that construction quality requires, the development of high efficiency water reducing agent more and more comes into one's own.

The effect of water reducer, the water yield that can obviously reduce when mixing and stirring concrete to be added increases substantially the flowing property and the intensity of concrete grout simultaneously, thereby improves the quality of engineering.American-European developed country from 20th century beginning thirties use cement water reducing agent in construction industry, the history surplus in the of existing nearly 70 year so far.At present, the rate of utilization of these national water reducers is more than 80%.And China has only 20%, but increases swift and violent.

High efficiency water reducing agent claims superplasticizer again, can reduce the workability of water consumption and raising fresh concrete significantly.High efficiency water reducing agent mainly contains following several: the modified lignin mahogany sulfonate water reducer; The naphthalene sulfonic acidformaldehyde condensation product water reducer; Melamine system water reducer; Sulfamate water reducer; Carboxylate salt graft copolymer water reducer; Fatty acid series water reducer etc.

Sulfonated lignin are the byproducts with paper mill waste liquid gained after operations such as sulfonation, spraying drying are handled, and the branch of calcium lignin sulphonate and sodium lignosulfonate is arranged, and what generally obtain is calcium lignin sulphonate, is referred to as sulfonated lignin.Because calcium lignin sulphonate is cheap, people extensively use it as ordinary water-reducing agent, at present domestic occurred by with its modification to improve water-reducing rate, make it reach the high efficiency water reducing agent standard techniques, but because the limitation of conditions such as technical recipe, the domestic ability that does not still possess scale operation at present.

The naphthalene sulfonic acidformaldehyde condensation product water reducer is present domestic production amount maximum, uses the widest high efficiency water reducing agent, its technology comparative maturity, and each factory's product quality level is more or less the same.The advantage of naphthalene water reducer is: water-reducing rate is higher, not bleed, and cement adaptability is good, and is good with various admixture composite performances.Can be used for preparing high-strength, high performance concrete.The subject matter that its exists be the slump through the time loss bigger, concrete is clamminess, and expensive raw material price.The naphthalene water reducer of existing market has 2 kinds on coventional type and highly enriched type.Coventional type generally contains 18%～22% Na ₂SO ₄, generally need composite use, to improve its water-reducing rate, reduce slump-loss; High dense type is with the Na in the coventional type naphthalene water reducer with chemical process ₂SO ₄Content reduces, and helps improving water-reducing rate, reduces slump-loss, prevents to produce because of temperature is low precipitation.But its technology is complicated.

Melamine resin water reducer full name is a sulfonated melamine compound resin, also claims melmac, is a kind of water-soluble polymeric resin, and the domestic later stage seventies succeeds in developing, and belongs to efficient non-gas tracting subtractive agent.Its performance and naphthalene are close, and resistance to elevated temperatures is better than naphthalene system, can be used for heat-resisting, refractory concrete.But because of its liquid product concentration is low, storage period is short, the slump through the time loss also big, concrete is clamminess, price is higher relatively, use face is not as good as naphthalene system.Domestic once the experiment replaces the part trimeric cyanamide with urea and comes modification reducing cost, but further promoted not as good as the pure melamine product fine because of its product performance eventually.

Sulfamate water reducer is a kind of non-bleed soluble resin water reducer.Advantage is: volume is little, water-reducing rate is high, the slump is little through time loss, is particularly useful for the less high performance concrete of water cement ratio, and its water-reducing rate can reach 30%.Shortcoming is: the molecular weight of thionamic acid based water reducer hour causes the cement slurry bleeding very much easily, and concrete slump loss is very fast; When molecular weight was too big, the diminishing dispersiveness was affected; Cause concrete bleeding when volume is high easily, emanate and harden; And its cost is higher.Sulfamate water reducer is to be formed by the condensation under certain condition of Sulphanilic Acid, phenol, formaldehyde.Also available aniline after sulfonation again with phenol, formaldehyde condensation.Also have at present with the condensation of urea instead of part sulfamate, but the purer thionamic acid salt error of effect is a little.

Carboxylate salt graft copolymer water reducer is a novel high-performance water reducer, and it has the following advantages; The water-reducing rate height, slump-loss is little, the later strength height: gain in strength was more than 20% in 28 days.Volume is less: generally below 0.3%.Though it is littler than naphthalene system or trimeric cyanamide to mix the Zeta potential value of cement slurry, its cement particle surface of this type of water reducer, the slump was not lost substantially at 1～2 hour.Its reason be carboxylic acid ion can with calcium Ca in the cement slurry ²⁺In conjunction with, the hydration rate that slowed down is not held back very fast reduction water reducer concentration because hydrate is less relatively.Also relevant with polycarboxylate in addition at the suction type of cement surface; it is three-dimensional spination absorption at cement surface its master chain molecular architecture decision; therefore the horizontal absorption mode that is different from naphthalene system has more three-dimensional electric protection effect, and can the long period keep the stably dispersing state.This type of water reducer is suitable for high performance concrete.Its shortcoming is: think capacitive poor, to concrete predictable poor, as: when poly carboxylic acid series water reducer and other admixtures used jointly, the loss of its slump was too fast and be prone to phenomenons such as fast hard, has cement and chemical admixture compatibility problem; In the concrete that uses high-performance water reducing agent, when unit water yield minimizing, when slump increases, following problem usually takes place: the water reducer consumption is excessive, concrete viscosity is too big, segregation excreting water phenomenon, pumping difficulty occur.And poly carboxylic acid series water reducer synthesis technique complexity, the raw material costliness.

The aliphatic sulfonate water reducer is developed as oil well cement additive by China's researcher the earliest, is mainly used in reinforcing oil well.Dispersion agent as oilfield cement, because it has good high-temperature stability and water-reducing effect, can significantly improve and keep the rheological of cement, when making grout have good workability, and later strength is increased obviously, thereby replaced the status of naphthalene sulfonic salt water reducer in oil well cement rapidly.Use in the cement dispersants in China oil field at present, the aliphatic sulfonate water reducer accounts for the market share more than 90%.

After this, the characteristic that the commerical ready-mixed concrete worker is had according to the aliphatic sulfonate water reducer, by a large amount of test works, according to its reaction principle, adopt various synthetic method and proportioning raw materials that its molecular weight and its structure are transformed, success applies to commerical ready-mixed concrete with it as cement dispersants, not only kept it to compare the high-temperature stability that is had as cement dispersants with naphthalene sulfonic salt water reducer, and synthesis technique is simple.Be applied in the commerical ready-mixed concrete as liquid product,, avoided sodium sulfate to precipitate the common phenomenon of the obstruction delivery tube that in commerical ready-mixed concrete pumping process, causes because of low temperature crystallization because of it does not contain the vitriol of separating out under the low temperature.

Aliphatic water reducing agent is based on carbonyl compound, form the aliphatics macromolecular chain of certain molecular weight size under certain condition with formaldehyde condensation, and open carbonyl by sulfonation reaction, introduce the wetting ability sulfonic acid group, it is a kind of polymeric surface active agent that contains hydrophilic radicals such as sulfonic group, hydroxyl, carboxyl, number-average molecular weight is between 3300～3500, its main raw material is acetone, formaldehyde and S-WAT, the prices of raw and semifnished materials are cheap and be easy to get, production cost is lower, uses aliphatic water reducing agent can reduce concrete starting material production cost significantly; The early strength development is very fast, and later strength also has the trend of growth; Good to cement adaptability, dispersive ability is strong, can effectively reduce hydration heat of cement, good water-retaining property, do not contain villaumite, reinforcing bar is not had corrosive nature, and compatibleness is good, it can reduce the cement particle surface current potential in cement-water-high efficiency water reducing agent system, has the electrostatic dispersion effect, and the negative potential of cement particle surface changes very for a short time in 1h, shows the multilayer adsorption feature generally at cement particle surface, and adsorption curve belongs to the LS type.Limit adsorptive capacity is greater than the limit adsorptive capacity of naphthalene series high-efficiency water-reducing agent.But aliphatic water reducing agent also has some shortcomings, as: under the situation of identical addition, water-reducing rate is lower than naphthalene system and poly carboxylic acid, and slump-loss is bigger, also exists the problem of using back cement variable color, therefore need carry out modification to it.

Summary of the invention:

The object of the present invention is to provide a kind of product of production to have high water reducing rate, the preparation method of the poly carboxylic acid modified fatty water-reducing agent of simple, the easy suitability for industrialized production of method.

Technical solution of the present invention is:

A kind of preparation method of poly carboxylic acid modified fatty water-reducing agent is characterized in that: comprise the following steps: successively

(1) preparation is poly carboxylic acid modified dose: maleic anhydride 15～25 weight parts, Hydroxyethyl acrylate 30～50 weight parts, vinylbenzene 15～25 weight parts and benzoyl peroxide 1～1.5 weight part are put into reactor, stir and heat up, reacted 2～3 hours down at 90～120 ℃, make poly carboxylic acid modified dose;

(2) add water 250～350 weight parts, sodium hydroxide 20～30 weight parts, sodium bisulfite 120～150 weight parts, acetone 100～120 weight parts in the reactor successively, be warming up to 60～70 ℃, add formaldehyde solution 350～450 weight parts then, and temperature of reaction is controlled at 75～85 ℃; Drip poly carboxylic acid modified dose 10～20 weight part that step (1) obtains then, reacted 2～4 hours, get product.

The water reducer of the present invention's preparation is that 0.6% o'clock water-reducing rate can reach 21% at volume, increase volume then water-reducing rate obviously improves, at volume is can reach 32% at 0.9% o'clock, 3 days ultimate compression strength of concrete improves more than 60%, ultimate compression strength improved more than 50% in 28 days, and ultimate compression strength improved more than 30% in 90 days; Concrete surface does not have bleeding line, no air pocket, aberration is little, concrete appearance good; Alkali content is low; Chloride ion-containing not is to the reinforcing bar non-corrosiveness; Freezing tolerance and anti-charing ability are significantly increased; The adaptation of product is strong, is applicable to plurality of specifications, model cement; Product performance are stable, and long storage does not have layering, do not have precipitation, do not have advantages such as crystallization winter.Simple, the easy suitability for industrialized production of method.

The invention will be further described below in conjunction with embodiment:

Embodiment:

A kind of preparation method of poly carboxylic acid modified fatty water-reducing agent comprises the following steps: successively

(1) preparation is poly carboxylic acid modified dose: maleic anhydride 15～25 weight parts (example 15,20,25 weight parts), Hydroxyethyl acrylate 30～50 weight parts (example 30,40,50 weight parts), vinylbenzene 15～25 weight parts (example 15,20,25 weight parts) and benzoyl peroxide 1～1.5 weight part (example 1,1.2,1.5 weight parts) are put into reactor, stir and heat up, reacted 2～3 hours down 90～120 ℃ (90 ℃, 110 ℃, 120 ℃ of examples), make poly carboxylic acid modified dose;

(2) add water 250～350 weight parts (example 250,200,350 weight parts), sodium hydroxide 20～30 weight parts (example 20,25,30 weight parts), sodium bisulfite 120～150 weight parts (example 120,135,150 weight parts), acetone 100～120 weight parts (example 100,110,120 weight parts) in the reactor successively, be warming up to 60～70 ℃ (60 ℃, 65 ℃, 70 ℃ of examples), add formaldehyde solution 350～450 weight parts (example 350,400,450 weight parts) then, and temperature of reaction is controlled at 75～85 ℃ (75 ℃, 80 ℃, 85 ℃ of examples); Drip poly carboxylic acid modified dose 10～20 weight part (example 10,15,20 weight parts) that step (1) obtains then, reacted 2～4 hours, get product.

Claims (1)

1, a kind of preparation method of poly carboxylic acid modified fatty water-reducing agent is characterized in that: comprise the following steps: successively

(1) preparation is poly carboxylic acid modified dose: maleic anhydride 15～25 weight parts, Hydroxyethyl acrylate 30～50 weight parts, vinylbenzene 15～25 weight parts and benzoyl peroxide 1～1.5 weight part are put into reactor, stir and heat up, reacted 2～3 hours down at 90～120 ℃, make poly carboxylic acid modified dose;

(2) add water 250～350 weight parts, sodium hydroxide 20～30 weight parts, sodium bisulfite 120～150 weight parts, acetone 100～120 weight parts in the reactor successively, be warming up to 60～70 ℃, add formaldehyde solution 350～450 weight parts then, and temperature of reaction is controlled at 75～85 ℃; Drip poly carboxylic acid modified dose 10～20 weight part that step (1) obtains then, reacted 2～4 hours, get product.