KR20130052932A - Light plaster mortar composition having improved wet adhesion - Google Patents

Abstract

PURPOSE: A heat insulating gypsum mortar composition for light weight in which interfacial adhesion is enhanced is provided to improve interfacial adhesion between blocks and mortars by using cellulose ether having a specific range of substitution degree as admixtures. CONSTITUTION: A heat insulating gypsum mortar composition for light weight in which interfacial adhesion is enhanced includes expanded polystyrene (EPS) as light weight aggregates and cellulose ether having a specific range of substitution degree as admixtures. The cellulose ether is one or more selected from a group including hydroxyethyl methylcellulose, hydroxypropyl methylcellulose and methyl cellulose. A methyl group substitution degree (MeO) of the cellulose ether is 28-31% and the substitution degree of hydroxypropyl (HPO) or hydroxyethyl (HEO) is 0-3%. 1.0-5.0 wt% of the EPS is used based on the total weight of the mortar composition. 0.05-0.5 parts by weight of the cellulose ether is used based on 100.0 parts by weight of the mortar composition including the EPS.

Description

Light Plaster Mortar Composition Having Improved Wet Adhesion

The present invention relates to a lightweight gypsum mortar composition which improves thermal insulation and improves interfacial adhesion with a mortar composition comprising gypsum as a binder, and more specifically, expands polystyrene (EPS) as a lightweight aggregate for thermal insulation. The present invention relates to a lightweight gypsum mortar composition which improves low interfacial adhesion between blocks and mortar by using a cellulose ether having a specific range of substitution degree as a admixture.

Lightweight mortar, which has emerged due to the increasing demand for materials with light weight as buildings become very high-rise, selects cement or gypsum as a binder according to the purpose of construction, and the types and ratios of light weight aggregates such as pumice and pearlite for lightening mortar. In addition, it is made by blending heavy aggregates such as slaked lime, sand and limestone as main components. In addition, admixtures are used to improve the thickening, water retention, transportability, and the like.

On the other hand, various cellulose ethers and derivatives thereof made of natural cellulose pulp are widely used as admixtures for mortar building materials using cement or gypsum as binders, under the name of thickener, water refining agent, or material separation reducing agent. have. Cellulose ethers incorporated into mortars exhibit inherent functions such as repair and thickening.

WO 2006/100531 discloses a light-weight mortar composition which can be applied simultaneously to walls and floors by mixing thickeners such as bentonite and cellulose ether with cement as a binder and 67% pumice as a main component for the purpose of light weight. .

Patent Publication No. 10-2010-0012554 discloses a lightweight interior and exterior materials with improved thermal insulation and sound absorption made of a gypsum composition comprising a foamed glass as an active ingredient.

In addition, US Pat. No. 4,654,085 discloses modified starch, polyacrylamide, and cellulose ether to solve the sag resistance that occurs in mortar, one of the important properties of gypsum or cement mortar. It discloses using the composition contained in a ratio.

Another US Patent 4,043,827 discloses the use of clay, longchain organic polymers to improve the sag resistance of dry mortar.

However, when the lightweight aggregate is used in the field of insulating gypsum mortar, the problem of material separation due to the uneven mixing of the lightweight aggregate, and also the deterioration of the interfacial adhesion occurring between the block and the mortar interface, is still not solved.

Therefore, the inventors of the present invention, while studying a lightweight insulating gypsum mortar, in the case of using a cellulose ether having a specific degree of substitution in the lightweight gypsum mortar composition to increase the thermal insulation effect by using expanded polystyrene as a lightweight aggregate, The present invention has been found to be able to improve the low adhesion between the block and mortar interface due to material separation caused by the use of lightweight aggregate.

Therefore, the problem to be solved by the present invention is a lightweight gypsum that improves the low interfacial adhesion between the block and mortar interface due to the separation of materials according to the use of lightweight aggregate It is to provide a mortar composition.

In order to solve the above problems, the present invention comprises a light weight gypsum mortar composition with improved interfacial adhesion, characterized in that it comprises a cellulose ether having a specific degree of substitution as a admixture to the light weight gypsum mortar composition comprising expanded polystyrene as a lightweight aggregate. To provide.

Here, the cellulose ether may be selected from the group consisting of hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose and methyl cellulose.

In addition, they have a methyl group substitution degree (MeO) of 28 to 31%, and a hydroxy propyl (HPO) group or hydroxyethyl (HEO) group substitution degree is preferably in the range of 0 to 3%.

Expanded polystyrene as the light weight aggregate is preferably used in the range of 1.0 to 5% by weight based on the total weight of the mortar composition.

Here, it is preferable that the expanded polystyrene has a unit volume weight of 11 to 14 g / l and a particle size of 0.2 to 0.4 mm.

In addition, the cellulose ether is preferably used in the range of 0.05 to 0.5 parts by weight based on 100 parts by weight of the mortar composition including the expanded polystyrene.

In the present invention, a lightweight gypsum with improved insulation effect using EPS as a lightweight aggregate A mortar composition can be obtained, and the following effects can be obtained by using a cellulose ether of a certain degree of substitution in such a composition.

First, it is possible to obtain the heat insulation effect by using the lightweight aggregate EPS in the light weight gypsum mortar, it can save energy by preventing heat loss.

Second, by preventing the separation of the material caused by the weight reduction of the lightweight gypsum mortar composition by using a cellulose ether of a certain degree of substitution, it facilitates the uniform mixing of the mortar.

Third, the uniform adhesion of the mortar improves the interface adhesion (Wet Adhesion) at the interface between the block and the mortar.

Hereinafter, the present invention will be described in more detail.

According to one embodiment of the present invention, the lightweight gypsum mortar composition comprising expanded polystyrene as a light weight aggregate, cellulose ether having improved interfacial adhesion, characterized in that it comprises a cellulose ether having a specific degree of substitution as a admixture Mortar composition.

 According to this embodiment, the thermal insulation effect can be increased by using expanded polystyrene (EPS) as the lightweight aggregate, and therefore, EPS can be included in an amount of 1.0 to 5.0% by weight based on the total weight of the gypsum mortar composition.

When the EPS content is less than 1% by weight, there is no thermal insulation effect, which is the effect of light weight gypsum mortar, and there is little light effect, and when the content exceeds 5.0% by weight, the improvement of the wet adhesion of the light weight mortar is improved. There is no effect, and sag resistance is also poor, which may cause difficulty in construction.

In addition, the EPS used preferably has a unit volume weight (g / L) of 11 to 14 and a particle size (mm) in the range of 0.2 to 0.4.

However, the use of EPS results in material separation due to EPS's hydrophilicity when mechanical mixing of water and mortar proceeds rapidly, resulting in a decrease in the wet adhesion of blocks and mortar. It can be bad.

To compensate for this, cellulose ethers having a certain degree of substitution are included as admixtures.

The cellulose ether having a specific degree of substitution may be selected from the group consisting of hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose and methyl cellulose, these are methyl group substitution degree (MeO) is 28 to 31%, Preferably, the degree of hydroxy propyl (HPO) or hydroxy ethyl (HEO) substitution is in the range of 0 to 3%.

The higher the degree of methyl group substitution, the higher the hydrophobicity (Hydrophobicity), the less the hydroxy propyl (HPO) or hydroxy ethyl (HEO) group also increases the hydrophobicity, resulting in material separation in the mortar of the EPS showing hydrophobicity Cellulose ethers exhibiting the same hydrophobicity can be used to prevent material separation, ultimately improving the Wet Adhesion between the block and mortar.

Therefore, when the degree of substitution of methyl group is less than 28%, that is, when the degree of substitution of hydroxypropyl (HPO) group or hydroxyethyl (HEO) group exceeds 3%, hydrophobic effect is reduced, thereby improving material separation of EPS. You may not be able to.

The cellulose ether having a specific degree of substitution as described above may be used as a foreign material at 0.05 to 5.0 parts by weight based on 100 parts by weight of the gypsum mortar composition, and the use of cellulose ether enables uniform mixing of water and mortar. As a result, it is possible to improve the adhesion between the block and the mortar interface by preventing the material separation phenomenon.

On the other hand, in the mortar composition, gypsum, inorganic fillers, slaked lime, and the like, which are generally used in this field, in addition to EPS, may be used as the lightweight aggregate.

The gypsum serves as a main binder, and as such gypsum, for example, hemihydrate gypsum having a condensation curing ability through a hydration reaction may be used, or anhydrous gypsum may be used.

As the inorganic filler, silica or limestone powder is mainly used, which serves to fill voids between the binder and the binder and to improve workability. Here, the 'binder' refers to gypsum particles which are mainly condensed and cured through chemical reaction with water to exert a bonding force.

The slaked lime plays a role of adjusting pH and improving workability.

In addition, functional additives such as modified starch, air entraining agent, and retardant may be used as the admixture, in addition to cellulose ether having a specific degree of substitution, wherein the retardant is mainly citric acid or tartaric acid. Organic acids or salts of organic acids are used and serve to secure working time by delaying the hydration of gypsum.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

Example  1 to 5 and Comparative example  One

Examples 1 to 5 and Comparative Example 1 confirmed the effect of the use of EPS as a lightweight aggregate on the thermal insulation effect.

Prepare the lightweight mortar composition of Examples 1 to 5 and Comparative Example 1 with the ingredients and contents shown in Table 1 below, gypsum having a particle size of 0.5mm or less, limestone powder having a particle size of 0.5 to 1.5mm as an inorganic filler and Gypsum mortar by mixing pulverized lime powder having a particle size of 0.5 mm or less, and finely divided limestone and particle size having a particle size of 0.5 mm or less, and EPS, followed by mixing cellulose ether, modified starch, air entrainer, and retardant as admixture. The composition was prepared.

division Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Example 5 gypsum <0.5mm 60 59 57 55 53 50 Lime lime <0.5mm 10 10 10 10 10 10 Unanalyzed <0.5mm 10 10 10 10 10 10 Limestone 0.5 ~ 1.5mm 20 20 20 20 20 20 Lightweight aggregate EPS 0 1.0 3.0 5.0 7.0 10.0 synthesis - 100 100 100 100 100 100 CE - 0.20 0.20 0.20 0.20 0.20 0.20 Modified starch - 0.02 0.02 0.02 0.02 0.02 0.02 Air entrainment - 0.015 0.015 0.015 0.015 0.015 0.015 Retardant - 0.05 0.05 0.05 0.05 0.05 0.05

EPS: Kommanditgesllschaft Herbert Dietrich Schulze GmbH, B933B

* CE: cellulose ether (HEMC with Brookfield viscometer at 20 ° C and 20rpm conditions, 2% by weight aqueous solution viscosity is 30,000cps, methyl group substitution degree 30%, hydroxyethyl group substitution degree 2%)

Modified starch: Hydropropyl starch

* Air entrainer: Olefin sulfonate

* Delay Retardant: Tartaric Acid

Evaluation example  One

The mortar compositions obtained from Examples 1 to 5 and Comparative Example 1 were measured for water demand, transfer pressure, flow, and thermal conductivity, and the results are shown in Table 2 below.

-Water demand : Measured by water level gauge of PFT G5

-Feed pressure : pressure measurement between feed lakes of PFT G5

- Full row: Measured in compliance with the EN 1015-3

- Thermal conductivity: measured in accordance with KS F9106, using a thermal conductivity analyzer.

division Water requirements Conveying pressure Pulley Thermal conductivity unit l / h bar mm W / m.K Comparative Example 1 800 10 170 0.85 Example 1 800 10 175 0.32 Example 2 800 10 181 0.40 Example 3 800 10 190 0.32 Example 4 800 10 200 1.04 Example 5 800 10 220 1.25

As can be seen from Table 2, when comparing Comparative Example 1 and Example 1, it can be seen that the thermal conductivity coefficient was reduced in the case of Example 1 using EPS, which indicates that the thermal insulation effect is improved.

On the other hand, in Example 4 and Example 5 having an EPS content of more than 5% by weight it was confirmed that the heat insulation effect is significantly reduced again.

Example  6 to 8 and Comparative example  2 to 3

The relationship between the substitution degree of the cellulose ether and the interfacial adhesion property was confirmed through Examples 6 to 9 and Comparative Example 2.

As shown in Table 3 below, referring to the compounding condition for lightweight insulation mortar guide, the insulation gypsum mortar was prepared as shown in Table 4 by varying the type and degree of substitution of the cellulose ether used.

division content gypsum <0.5mm 57 Lime lime <0.5mm 10 Differential limestone <0.5mm 10 Limestone 0.5 ~ 1.5mm 20 Lightweight aggregate EPS 3 synthesis - 100 CE - 0.20 Modified starch - 0.02 Air entrainment - 0.015 Retardant - 0.05

division Type of CE Methyl group substitution degree (%) Hydroxypropyl (HPO) or hydroxyethyl substitution degree (%) Comparative Example 2 HEMC 23 9 Comparative Example 3 HPMC 23 9 Example 6 HEMC 28 3 Example 7 HPMC 28 3 Example 8 MC 30 0

HEMC: hydroxyethyl methyl cellulose

* HPMC: hydroxypropyl methyl cellulose

* MC: methyl cellulose

Evaluation example  2

The mortar compositions obtained from Examples 6 to 8 and Comparative Examples 2 to 3 were evaluated for water demand, transfer pressure, pulley, amount of mortar dropped, and sag resistance, and the results are shown in Table 5 below.

-The amount of mortar dropped :: When 20KG mortar is manufactured by dry mortar mixing method (V-mixer, 20 minutes) and mixed with water using PFT G5 continuous mixer, the mortar is sprayed on the block of 1㎡ area. Total amount of falling off (g)

-Deflection resistance : After spraying with a mechanical mixer, the mortar does not fall off the wall and is visually scored. (The higher the score, the higher the number.)

division Water requirements Conveying pressure Pulley Fallen
Mortar Deflection resistance unit l / h bar mm g Sensuality Comparative Example 2 780 12 177 640 Xx Comparative Example 3 780 12 176 520 ○ ◐ Example 6 780 12 175 200 ○○○ Example 7 780 12 175 200 ○○○ Example 8 780 12 176 100 ○○○

As can be seen from Table 5, it can be seen that as the degree of substitution of the methyl group is increased, the amount of mortar dropped is reduced, in particular, when the degree of substitution of methyl group is increased to 28% or more, the amount of mortar dropped significantly decreases. It can be confirmed that this indicates that the interface adhesion between the block and the mortar is improved.

In addition, when comparing Comparative Example 2 and Comparative Example 3, the amount of mortar dropped by HPMC compared to HEMC was slightly less, but in Examples 7 and 8, regardless of the substituent, if the degree of substitution of the methyl group is 28% or more, It can be seen that one mortar amount is similar.

Through the above examples, it was confirmed that the EPS content is 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the light weight mortar composition, and the methyl group substitution degree is 28 to 31%, hydroxypropyl or hydroxy ethyl. When using a cellulose ether having a substitution degree of 0 to 3%, it is confirmed that the interface adhesion between the block and the mortar is improved by preventing the material separation phenomenon generated when the lightweight aggregate is used as the material.

Although the present invention has been described with reference to the examples, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (4)

A lightweight gypsum mortar composition comprising expanded polystyrene as a lightweight aggregate, comprising cellulose ethers having a specific degree of substitution as admixtures,
Here, the cellulose ether is selected from the group consisting of hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose and methyl cellulose,
Herein, the methyl group substitution degree (MeO) of the cellulose ether is 28 to 31%, and the hydroxypropyl (HPO) group or the hydroxyethyl (HEO) group substitution degree is 0 to 3%. Mortar composition.
The method of claim 1,
The light weight aggregate expanded polystyrene is used in the range of 1.0 to 5% by weight based on the total weight of the mortar composition Lightweight gypsum mortar composition with improved interfacial adhesion.
The method according to claim 1,
The light weight aggregate expanded polystyrene has a unit volume weight of 11 to 14 g / l, the light weight gypsum mortar composition with improved interfacial adhesion of the particle size of 0.2 to 0.4mm.
The method of claim 1,
The cellulose ether is light weight gypsum mortar composition with improved interfacial adhesion is used in the range of 0.05 to 0.5 parts by weight based on 100 parts by weight of the mortar composition containing the expanded polystyrene.