KR20110089657A - Cement additive composition and cement composition having the additive composition - Google Patents

Abstract

PURPOSE: A cement additive composition is provided to improve water retention property and workability and to reduce water pocket and efflorescence by comprising cellulose ether, polyvinyl alcohol-based resin and redispersible powder resin. CONSTITUTION: A cement additive composition comprises cellulose ether, polyvinyl alcohol-based resin and redispersible powder resin. Cellulose ether includes at least one kind selected from the group consisting of methyl cellulose with the methyl substitution degree(DS) of 0.1~2.9, hydroxypropylmethylcellulose with the methyl substitution degree(DS) of 0.1~2.9 and the hydroxypropyl substitution degree(MS) of 0.01~2 hydroxyethylcellulose with the hydroxypropyl substitution degree(MS) of 0.1~10.0, ethylhydroxyethylcellulose with the ethyl substitution degree(DS) of 0.1~2.9 and the hydroxypropyl substitution degree(MS) of 0.01~2, and methylethylhydroxyethylcellulose with the methyl and ethyl substitution degree(DS) of 0.1~2.9 and the hydroxypropyl substitution degree(MS) of 0.01~2.

Description

Cement additive composition and cement composition comprising the additive composition

Cement additive compositions and cement compositions comprising the additive compositions are disclosed. More specifically, a cement additive composition comprising a cellulose ether, a polyvinyl alcohol-based resin, and a redispersible powder resin, and a cement composition comprising the additive composition are disclosed.

In the cement composition for concrete surface treatment, cellulose ether is widely used for the purpose of imparting water retention.

In the case of using high viscosity cellulose ethers among these cellulose ethers, poor workability is used, and many low and medium viscosity cellulose ethers are used. However, when only cellulose ether is used, water retention is improved and the surface of the cement composition is reduced in surface dryness, but it is difficult to improve workability, whitening (dust), water spray, and pot life. .

One embodiment of the present invention provides a cement additive composition comprising a cellulose ether, a polyvinyl alcohol-based resin and a redispersible powder resin.

Another embodiment of the present invention provides a cement composition comprising the additive composition.

One aspect of the invention,

It provides a cement additive composition comprising a cellulose ether, a polyvinyl alcohol-based resin and a redispersible powder resin.

The cellulose ether is methyl cellulose having a methyl group substitution degree (DS) of 0.1 to 2.9, hydroxypropyl methyl cellulose having a methyl group substitution degree (DS) of 0.1 to 2.9 and a hydroxypropyl group substitution degree (MS) of 0.01 to 2, and a methyl group Hydroxyethylmethylcellulose having a degree of substitution (DS) of 0.1 to 2.9 and a degree of substitution of hydroxyethyl group (MS) of 0.01 to 2, hydroxyethylcellulose having a degree of substitution of hydroxyethyl group (MS) of 0.1 to 10.0, ethyl group substitution degree Ethyl hydroxyethyl cellulose (DS) having 0.1 to 2.9 and hydroxyethyl group substitution degree (MS) of 0.01 to 2, methyl group and ethyl group substitution degree (DS) of 0.1 to 2.9 and hydroxyethyl group substitution degree (MS) of 0.01 It may include at least one member selected from the group consisting of methyl ethyl hydroxyethyl cellulose of ˜2.

The 2 (w / v)% aqueous solution of the cellulose ether, the viscosity measured at 20 ℃ and 20rpm using a Brookfield viscometer may be 10 ~ 200,000cps.

The polyvinyl alcohol-based resin may include at least one resin selected from the group consisting of polyvinyl alcohol and derivatives thereof.

Hydrolysis degree of the polyvinyl alcohol may be 10 to 100 mol%.

The polyvinyl alcohol derivative may include at least one of polyvinyl butyral, polyvinyl formal and polyvinyl acetal.

The redispersible powder resin is a vinyl acetate homopolymer, a vinyl acetate / vinyl versatate, a vinyl acetate / ethylene copolymer, a vinyl acetate / veh Vinyl acetate / VeoVa copolymer, vinyl acetate / VeoVa / acrylate terpolymer vinyl acetate / ethylene / vinyl chloride terpolymer, butyl Butyl acrylate / vinyl acetate / vinyl versatate terpolymer, vinyl acetate / vinyl versatate / ethylene terpolymer, and vinyl acetate / vinyl versatate At least one selected from the group consisting of vinyl acetate / vinyl versatate / acrylate terpolymer It may include one kind of polymer.

The cement additive composition may include 0.1 to 50 parts by weight of the polyvinyl alcohol-based resin and 0.1 to 50 parts by weight of the redispersible powder resin based on 100 parts by weight of the cellulose ether.

The cement additive composition may further include at least one auxiliary additive selected from the group consisting of starch, polyacrylamide, a water reducing agent for cement / concrete, a super absorbent resin, and a surfactant.

Another aspect of the invention,

It provides a cement composition comprising cement and the cement additive composition.

The content of the cement additive composition may be 0.01 to 10 parts by weight based on 100 parts by weight of the cement.

The cement composition may be for concrete surface treatment.

According to one embodiment of the present invention, by including cellulose ether, polyvinyl alcohol-based resin and redispersible powder resin, when applied to cement pastes, water retention, workability and working time is improved, and water and whitening are reduced. Cement additive compositions may be provided.

According to another embodiment of the present invention, a cement composition including the additive composition may be provided to enable clean concrete surface treatment.

Hereinafter, it will be described in detail with respect to the cement additive composition according to an embodiment of the present invention.

Cement additives according to one embodiment of the present invention include cellulose ether, polyvinyl alcohol-based resin and redispersible powder resin.

The cellulose ether is methyl cellulose having a methyl group substitution degree (DS) of 0.1 to 2.9, hydroxypropyl methyl cellulose having a methyl group substitution degree (DS) of 0.1 to 2.9 and a hydroxypropyl group substitution degree (MS) of 0.01 to 2, and a methyl group Hydroxyethylmethylcellulose having a degree of substitution (DS) of 0.1 to 2.9 and a degree of substitution of hydroxyethyl group (MS) of 0.01 to 2, hydroxyethylcellulose having a degree of substitution of hydroxyethyl group (MS) of 0.1 to 10.0, ethyl group substitution degree Ethyl hydroxyethyl cellulose (DS) having 0.1 to 2.9 and hydroxyethyl group substitution degree (MS) of 0.01 to 2, methyl group and ethyl group substitution degree (DS) of 0.1 to 2.9 and hydroxyethyl group substitution degree (MS) of 0.01 It may include at least one member selected from the group consisting of methyl ethyl hydroxyethyl cellulose of ˜2.

The degree of substitution of methyl group (DS (MeO)), degree of substitution of hydroxyethyl group (MS _EO ) and degree of substitution of hydroxypropyl group (MS _PO ) may be calculated by Equation 1, Equation 2 and Equation 3, respectively. .

[Equation 1]

[Equation 2]

&Quot; (3) "

In the above formulas,% OCH3 (% by weight of methyl group in cellulose ether),% EOOH (% by weight of hydroxyethyl group in cellulose ether) and% POOH (% by weight of hydroxypropyl group in cellulose ether) are 0.01-50, 0.01 to 70 and 0.01 to 50.

By applying a cement additive composition comprising a cellulose ether having a range of substitution degree to the cement composition, the finally formed cement paste not only has excellent viscosity expression, but also reduces the amount of air mixing in the mixing process for producing the cement paste. As the bubble generation is reduced to have excellent water retention. In the present specification, the 'cement paste' means a mixture of the cement additive composition with cement and water in a predetermined ratio and kneaded.

An aqueous solution of 2 (w / v)% of cellulose ether is 10-200,000 cps, for example 3,000-100,000 cps, for example 3,000-50,000 cps, as measured at 20 ° C. and 20 rpm using a Brookfield viscometer. It may have a viscosity. When the viscosity is less than 10 cps, the repair rate is insufficient in the normal use range and the thickening effect is insignificant. When the viscosity exceeds 200,000 cps, the water retainability is improved but the workability of the cement paste may be deteriorated.

The polyvinyl alcohol-based resin is to improve the workability and molten properties in the case of cement paste, it may include polyvinyl alcohol and / or derivatives thereof. The polyvinyl alcohol (PVA) may be prepared through partial hydrolysis or full hydrolysis to remove the acet group of polyvinylacetate. The chemical properties of these polyvinyl alcohols are similar to those of conventional alcohols.

In addition, the degree of hydrolysis of the polyvinyl alcohol may be 10 to 100 mol%, for example, 30 to 100 mol%, for example, 60 to 100 mol%. If the degree of hydrolysis of the polyvinyl alcohol is less than 10 mol%, solubility in water is low, which is not preferable. In addition, the polyvinyl alcohol derivative may include at least one resin selected from the group consisting of polyvinyl butyral, polyvinyl formal and polyvinyl acetal. Such polyvinyl alcohol derivatives can be prepared by treating polyvinyl acetate with an acid or a base to remove the acetic acid group without breaking the long chain structure of the molecule. At this time, since the acetic acid group is not completely removed, it may be insoluble in water but may be made in some organic solvents. Polyvinyl butyral may be prepared by the reaction of polyvinyl alcohol and butyraldehyde, polyvinyl formal may be prepared by the reaction of polyvinyl alcohol and formaldehyde, polyvinyl acetal is polyvinyl alcohol and acetyl It can be prepared by the reaction of an aldehyde.

The redispersible powder resin improves the workability of the cement paste and reduces the whitening phenomenon after the work is completed. The redispersible powder resin can significantly reduce the occurrence of whitening by increasing the strength of the cement paste coating film comprising the cement additive composition. Such redispersible powder resins include vinyl acetate homopolymer, vinyl acetate / vinyl versatate, vinyl acetate / ethylene copolymer, vinyl acetate / Vinyl acetate / VeoVa copolymer, vinyl acetate / VeoVa / acrylate terpolymer vinyl acetate / ethylene / vinyl chloride terpolymer, butyl Butyl acrylate / vinyl acetate / vinyl versatate terpolymer, vinyl acetate / vinyl versatate / ethylene terpolymer, and vinyl acetate / vinyl versatate Red selected from the group consisting of vinyl acetate / vinyl versatate / acrylate terpolymer Also it can be a polymer of one kind.

The cement additive composition may include 0.1 to 50 parts by weight of the polyvinyl alcohol-based resin and 0.1 to 50 parts by weight of the redispersible powder resin based on 100 parts by weight of the cellulose ether. If the content of the polyvinyl alcohol-based resin is less than 0.1 part by weight based on 100 parts by weight of the cellulose ether, the effect of addition is insignificant, and if it exceeds 50 parts by weight, the inherent physical properties of the cellulose ether are lowered, which is not preferable. In addition, when the content of the redispersible powder resin is less than 0.1 parts by weight, the effect of addition is insignificant, and if it exceeds 50 parts by weight, the cost increases due to the high price and the inherent physical properties of the cellulose ether is lowered, which is not preferable.

The cement additive composition may further include at least one auxiliary additive selected from the group consisting of starch, polyacrylamide, a cement / concrete water reducing agent, a super absorbent polymer, and a surfactant.

The starch may include at least one selected from the group consisting of general starch, dextrin, and modified starch.

The cement / concrete water reducing agent may be a delayed type such as a conventional water reducing agent, an AE water reducing agent, a high performance water reducing agent, and / or a high performance AE water reducing agent used as a cement admixture.

The super absorbent polymer may include at least one selected from the group consisting of sodium carboxy methylcellulose, polyacrylic acid / polyvinylamine copolymer, and polyacrylic acid / natural polymer copolymer. Can be.

The surfactant may include at least one of anionic surfactants and nonionic surfactants.

The anionic surfactants include sulfonates such as alkylbenzene sulfonates, alkanes sulfonates, petroleum sulfonates, lignin sulfonates or ester sulfonates; Sulfates such as alkyl sulfates or alkyl ether sulfates; Esters such as sulfosuccinate esters or isethionate esters; Amino acids such as N-acylated amino acids; And at least one compound selected from the group consisting of soaps such as sodium stearate.

The nonionic surfactants include ethoxylated compounds such as ethoxylated alcohols, ethoxylated alkylphenols, ethoxylated acids or ethoxylated esters; Alkanolamides such as fatty acid alkanolamide or ethoxylated alkanolamide; Esters of polyhydroxyl compounds such as sorbitan distearate; Ethylene oxide-propylene oxide block copolymers; And at least one compound selected from the group consisting of amine oxides.

In addition, one embodiment of the present invention provides a cement composition comprising the cement and the cement additive composition. In this case, the content of the cement additive composition may be 0.01 to 10 parts by weight, for example 0.1 to 5 parts by weight, for example 0.1 to 2 parts by weight, based on 100 parts by weight of the cement. If the content is less than 0.01 parts by weight, it is not preferable to improve the physical properties such as improving workability, reducing water droplets, reducing whitening phenomenon and increasing working time, and when the content exceeds 10 parts by weight, the workability is degraded or the cement is hydrated. This is undesirable because the delay is excessive. The cement paste can be prepared by adding a predetermined amount of water to such cement composition and kneading in a constant manner. In this case, water is added in an amount sufficient to ensure the workability of the cement paste which is usually required.

In addition, the cement composition may be for concrete surface treatment, but the present invention is not limited thereto. In the present specification, 'concrete surface treatment' refers to finishing a paint or finishing work before spreading a thin layer of cement paste after removing irregularities or bumps on a concrete surface.

The main performance of cement paste required for concrete surface treatment is as follows.

(1) Whitening phenomenon: Since concrete surface treatment is to apply a thin layer of cement paste on the concrete surface with a thickness of 0.05mm, the whitening phenomenon is not easily generated by this concrete surface treatment. However, (i) the calcium hydroxide produced when the cement is hydrated is exposed to the surface of the cement paste, which then reacts with carbon dioxide in the air to form calcium carbonate resulting in the surface of the cement paste becoming white, and / or (ii) It occurs during the summer, when the water retention is low or the strength of the cement paste coating film is weak, when the rub the surface of the coating film after drying, whitening phenomenon occurs. Therefore, it is necessary to reduce the whitening phenomenon in the concrete surface treatment work.

(2) Water strip: For finishing work such as paint work, the surface should be evenly distributed so there should be little water drop. In the present specification, 'mulbo' refers to a shape that is generated by the voids formed in the concrete and the cement paste does not penetrate into the pores of the concrete and swells like a bubble.

(3) Workability: Workability is important because work is done by hand over a large area.

(4) Curlability: When the cement paste is first applied to the concrete surface with a thickness of 0.05mm or less, and then the chaebol is applied, the first applied cement paste should not roll out.

(5) Wipeability: When brushing, the applied cement paste should not be wiped out by the brush with water.

(6) Pot Life: The working time should be long for concrete surface treatment work, and usually work time of about 1 hour is required.

By applying the cement additive composition to the cement paste, by providing water retention and viscosity to the cement paste to improve the workability and increase the workable time, it is also possible to obtain the effect of improving the water droplets.

In addition, an important requirement for surface treatment of concrete is the quality of the walls after the work is completed. If there is a stain on the wall after the work is completed, the wall after the work is not clean when the final finishing work is done with paint on the wall. In addition, when the final finishing work with the paint on the wall where a lot of bleaching occurs a lot, the phenomenon that the paint is desorbed after time may occur. Therefore, it is important to use the above-mentioned cement additive composition for the final finishing work with less water and whitening phenomenon.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these embodiments.

Example  1 and 2 and Comparative example  1-5: Preparation of cement additive composition and cement composition

A cellulose ether, polyvinyl alcohol, redispersible powdered resin and auxiliary additives were mixed in the proportions shown in Table 1 to prepare a cement additive composition. Subsequently, the cement additive composition prepared above was mixed in an amount of 0.525 parts by weight based on 100 parts by weight of cement (usually Portland Cement of Asia Cement) to prepare a cement composition.

division Composition of Cement Additive Composition (parts by weight) Cellulose ether ^{* 1} Polyvinyl Alcohol Resin Redispersible Powder Resin Auxiliary additives A ₁ ^{* 2} A ₂ ^{* 3} B ₁ ^{* 4} B ₂ ^{* 5} C ^{* 6} Example 1 100 6 0 7 0 10 Example 2 100 0 10 0 2 10 Comparative Example 1 100 0 0 0 0 0 Comparative Example 2 100 2 0 0 0 10 Comparative Example 3 100 0 5 0 0 10 Comparative Example 4 100 0 0 3 0 10 Comparative Example 5 100 0 0 0 10 10

* 1: methyl cellulose (PMC-15US (DS: 1.45, MS: 0.22), 2 (w / v)% aqueous solution viscosity 15,000 cps of Samsung Fine Chemicals Co., Ltd.))

* 2: Polyvinyl alcohol with a hydrolysis degree of 85 mol% (Dongyang Steel Chemical, CT2000)

* 3: Polyvinyl alcohol having a hydrolysis degree of 95 mol% (Dongyang Steel Chemical, M17A)

* 4: vinyl acetate / vinyl versatate / ethylene trimer (Elotex EV2000)

* 5: vinyl acetate / ethylene copolymer (Elotex 50E)

* 6: 8.5 parts by weight of starch (targeted) + 0.5 parts by weight of polyacrylamide (Degussa) + 1.0 part by weight of super absorbent polymer (sodium carboxy methycellulose)

Evaluation example

The cement compositions prepared in Examples 1 to 2 and Comparative Examples 1 to 5 were respectively dry-blended, and then 100 parts by weight of each of the dry-beamed cement compositions were dispersed in 45 parts by weight of water, and the total amount was added within 3 minutes. Thereafter, the mixture of cement composition and water was aged for about 10 minutes, and then manually mixed to prepare a cement paste.

Samples of the prepared cement paste were collected and evaluated for water retention, workability, mop, wiping, curling, working time and whitening in the following manner, and the evaluation results are shown in Table 2 below.

(1) Water retention: Place one 5A filter on the lower end of the ring with diameter of 100mm and height of 10mm, fill the paste sufficiently kneaded in the ring, and after 30 minutes, water is absorbed and spread through the 5A filter (filter size: 150mm in diameter). Outgoing diameter was measured and water retention was evaluated. That is, conservativeness was calculated by the following equation.

&Quot; (4) "

Water retention (%) = 200- (diameter of wetted filter area after 30 minutes)

(2) Workability: After applying the cement paste prepared on the concrete surface, it was quantified by a five-point method by evaluating whether the trowel was pushed well without resistance during the thin spreading with a trowel. Higher scores indicate better workability.

(3) Moulbobo: When the cement paste is thinly applied on the concrete surface, and then brushed with a brush with water, the number of occurrences of bubbles are generated and burst like soap bubbles in the pores of the concrete surface to evaluate the number of occurrences It was.

(4) Wipeability: After thinly applying the cement paste prepared above to the concrete surface, it was visually evaluated whether the cement paste was peeled off when brushed with a brush with water and quantified by a five-point method. The higher the score, the greater the resistance to scrubbing, which means that it does not peel off.

(5) Curing property: When the cement paste thinly applied to the concrete surface was peeled off due to poor adhesion between the concrete and the cement paste, it was quantified by the 5-point method. The higher the score, the greater the resistance to curling and the less peeling.

(6) Pot life: The potable time is to mix the cement composition with water to produce a cement paste, and then apply the cement paste to the concrete surface every 10 minutes to remix without loss of workability. It was evaluated whether work was possible. The time required for workability to fall below 3 points was defined as workable time.

(7) Whitening phenomenon: After thin coating of the cement paste prepared on the gypsum board, after 12 hours of hardening, visually assessing whether the surface of the cement paste turns white and evaluating the generation of CaCO _{3 on} the surface. It was. The production of CaCO ₃ was analyzed using an X-ray diffractometer on the sample scraped off the surface.

division Performance of Cement Composition Conservative
(%) Workability Water bear
(ea) Wipeability Curling Working time
(min) Whitening phenomenon Example 1 96 5 One 3 4 330 Nil Example 2 96 5 One 3 5 310 Nil Comparative Example 1 99 One 5 3 One 240 多少 有 Comparative Example 2 97 3 3 3 One 270 多少 有 Comparative Example 3 97 5 One 3 3 280 多少 有 Comparative Example 4 97 3 5 3 3 260 多少 有 Comparative Example 5 96 3 5 3 3 290 多少 有

Referring to Table 2, the cement paste to which the cement composition prepared in Examples 1 and 2 is applied, compared to the cement paste to which the cement composition prepared in Comparative Examples 1 to 5 is applied, water retention, workability, moistening property, wiping property, It was found to be the same or superior in almost all performances such as curling, working time and whitening.

Although the present invention has been described with reference to the drawings and embodiments, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (12)

Cement additive composition comprising cellulose ether, polyvinyl alcohol-based resin and redispersible powder resin. The method of claim 1,
The cellulose ether is methyl cellulose having a methyl group substitution degree (DS) of 0.1 to 2.9, hydroxypropyl methyl cellulose having a methyl group substitution degree (DS) of 0.1 to 2.9 and a hydroxypropyl group substitution degree (MS) of 0.01 to 2, and a methyl group Hydroxyethylmethylcellulose having a degree of substitution (DS) of 0.1 to 2.9 and a degree of substitution of hydroxyethyl group (MS) of 0.01 to 2, hydroxyethylcellulose having a degree of substitution of hydroxyethyl group (MS) of 0.1 to 10.0, ethyl group substitution degree Ethyl hydroxyethyl cellulose (DS) having 0.1 to 2.9 and hydroxyethyl group substitution degree (MS) of 0.01 to 2, methyl group and ethyl group substitution degree (DS) of 0.1 to 2.9 and hydroxyethyl group substitution degree (MS) of 0.01 A cement additive composition comprising at least one member selected from the group consisting of methyl ethyl hydroxyethyl cellulose of ˜2. The method of claim 1,
2 (w / v)% aqueous solution of the cellulose ether, the cement additive composition having a viscosity of 10 ~ 200,000cps measured at 20 ℃ and 20rpm using a Brookfield viscometer. The method of claim 1,
The polyvinyl alcohol-based resin is a cement additive composition comprising at least one resin selected from the group consisting of polyvinyl alcohol and derivatives thereof. The method of claim 4, wherein
Hydrolysis degree of the polyvinyl alcohol is 10 ~ 100 mol% cement additive composition. The method of claim 4, wherein
The polyvinyl alcohol derivative is a cement additive composition comprising at least one resin selected from the group consisting of polyvinyl butyral, polyvinyl formal and polyvinyl acetal. The method of claim 1,
The redispersible powder resin is a vinyl acetate homopolymer, a vinyl acetate / vinyl versatate, a vinyl acetate / ethylene copolymer, a vinyl acetate / veh Vinyl acetate / VeoVa copolymer, vinyl acetate / VeoVa / acrylate terpolymer vinyl acetate / ethylene / vinyl chloride terpolymer, butyl Butyl acrylate / vinyl acetate / vinyl versatate terpolymer, vinyl acetate / vinyl versatate / ethylene terpolymer, and vinyl acetate / vinyl versatate At least one selected from the group consisting of vinyl acetate / vinyl versatate / acrylate terpolymer Cement additive composition comprising a polymer of one kind. The method of claim 1,
A cement additive composition comprising 0.1 to 50 parts by weight of the polyvinyl alcohol-based resin and 0.1 to 50 parts by weight of the redispersible powder resin based on 100 parts by weight of the cellulose ether. The method of claim 1,
A cement additive composition further comprising at least one auxiliary additive selected from the group consisting of starch, polyacrylamide, a water reducing agent for cement / concrete, a super absorbent resin, and a surfactant. cement; And
A cement composition comprising the cement additive composition according to claim 1. The method of claim 10,
The content of the cement additive composition is 0.01 to 10 parts by weight based on 100 parts by weight of the cement composition. The method of claim 10,
Cement composition for concrete surface treatment.