WO2018101613A1 - Autoclaved lightweight concrete adhesive composition, and autoclaved lightweight concrete adhesive comprising same - Google Patents

Abstract

The present invention relates to an autoclaved lightweight concrete (ALC) adhesive composition and an ALC adhesive comprising the same, the ALC adhesive composition comprising: a dry mixture comprising an inorganic binder and an aggregate; and a hydroxyalkyl alkyl cellulose having an alkyl group degree of substitution (DS) of 1.0-1.8 and having a hydroxyalkyl group degree of molar substitution (MS) of 0.2-1.2, wherein the 2 wt% aqueous solution viscosity of the hydroxyalkyl alkyl cellulose is 10,000-100,000 cps when measured by a Brookfield viscometer in a condition of 20°C and 20 rpm. According to the present invention, the ALC adhesive composition comprises a hydroxyalkyl alkyl cellulose having a suitable viscosity and degree of substitution, thereby enabling an ALC adhesive, which has high water retention capacity and high adhesive strength and is applicable to ALC having a high porosity, to be provided.

Description

Adhesive composition for lightweight foamed concrete and adhesive for lightweight foamed concrete comprising same

The present invention relates to an adhesive composition for lightweight foamed concrete and an adhesive for lightweight foamed concrete comprising the same, and more particularly, to an adhesive composition for lightweight foamed concrete comprising hydroxyalkyl alkyl cellulose having a viscosity and substitution degree appropriately adjusted. It relates to a high water-retaining and high adhesive strength light-weight foam adhesive including the same.

Autoclave lightweight concrete (ALC) is a lightweight concrete that forms a lot of bubbles in concrete and is a kind of lightweight concrete that is a special concrete. The ALC is used as an alternative material for brick and concrete, which is a material for construction of a conventional wall due to excellent light weight, heat insulation, fire resistance, and workability.

For example, the ALC is 4 to 5 times lighter than the standard concrete, so the structure cost is reduced and the insulation performance is very good. Therefore, the ALC can save energy more than 10 times compared to the general concrete. There is an advantage. Due to the characteristics of the inorganic material, it also possesses fire resistance, and its excellent workability, which can be easily processed by general wood tools, can be considered as an advantage.

The ALC is produced and sold in the form of a panel or a block reinforced with reinforcing bars. In order to construct the ALC, adhesion between the ALC products is important. Generally, adhesive mortars such as adhesive mortars, such as cellulose ethers, used as thickeners in most cases were used as adhesives of the ALC products.

The cellulose ether is a thickener based on natural materials, and exhibits an excellent thickening effect even with a small amount of addition, and unlike other chemical thickeners, has excellent water retention. In addition, the cellulose ether is a material that is very suitable for satisfying the physical properties such as prevention of material separation required for the thickener for construction, improving workability, maintaining moisture required for the hardening of cement, improving adhesion, improving shape retention, and improving sag resistance.

As a conventional technique for the adhesive mortar containing such a cellulose ether, Patent Document 1 (Domestic Patent Publication No. 10-0069257) discloses 100 to 180 parts by weight of silica and 0.01 to 5 parts by weight of methyl cellulose based on 100 parts by weight of cement. , About 0.01 to 5 parts by weight of PVA, 0.001 to 5 parts by weight of a reducing agent, 0.1 to 10 parts by weight of gypsum, 0.001 to 5 parts by weight of an antifoaming agent, and 0.01 to 10 parts by weight of a vinyl ester copolymer. It is described that the cement adhesive composition is suitably used for inorganic tiles, stone, and the like.

 However, when the adhesive prepared from the cement-based adhesive composition according to Patent Document 1 is applied to ALC, the moisture of the cement-based adhesive is lost to the ALC due to the characteristics of the ALC having a higher porosity than that of the brick, thereby lowering the adhesive strength. Occurred. That is, only the cellulose ethers such as methyl cellulose used in the cement-based adhesive composition known in Patent Document 1, it was difficult to maintain the water retention of the adhesive during the ALC construction.

 In addition, Patent Document 2 (Domestic Patent Application Publication No. 10-2013-0078223) discloses a light-weight board adhesive composition such as ALC board, the adhesive composition is 10 to 40 parts by weight of cement, blast furnace slag fine powder 10 ~ 40 parts by weight, 10 to 40 parts by weight of fly ash, 10 to 50 parts by weight of light fine powder, 0.015 to 5.0 parts by weight of a thickener such as methyl cellulose, and the like, based on 100 parts by weight of the mixture mixed to include 25 to 70 parts by weight of an alkali silicate solution. .

However, Patent Document 2 also uses a cellulose ether such as methyl cellulose used in general adhesive mortar for bricks as a thickener, and thus, the problem of lowering the adhesive strength due to moisture reduction, etc. has not been solved.

Therefore, it is necessary to develop an adhesive for ALC to which high water-retaining cellulose ether is applied, which can express excellent adhesive strength when constructing ALC products having high porosity.

[Preceding technical literature]

[Patent Documents]

(Patent Document 1) KR100069257 B

(Patent Document 2) KR1020130078223 A

The problem to be solved by the present invention is to provide a composition capable of producing an adhesive for ALC excellent in water retention and adhesive strength by including hydroxyalkyl alkyl cellulose having an appropriate viscosity and substitution degree.

Another object of the present invention is to provide an adhesive for ALC comprising the composition.

In order to solve the above problems, the present invention is a dry mixture comprising an inorganic binder and aggregate; And hydroxyalkyl alkyl cellulose having an alkyl group substitution degree (DS) of 1.0 to 1.8 and a hydroxyalkyl group substitution degree (MS) of 0.2 to 1.2; wherein the 2 wt% aqueous solution viscosity of the hydroxyalkyl alkyl cellulose is Brookfield It provides an adhesive composition for ALC, characterized in that 10,000 ~ 100,000cps when measured at 20 ℃ and 20rpm conditions with a viscometer.

The dry mixture may further include at least one selected from the group consisting of reemulsifying powder resins and curing accelerators.

The re-emulsifying powder resin may include at least one selected from the group consisting of ethylene-vinylacetate, acrylic latex, and styrene-butadiene rubber, and more preferably ethylene-vinylacetate. And, the content of the re-emulsifying powder resin may be 0.1 ~ 10.0% by weight based on 100% by weight of the dry mixture.

The curing accelerator is calcium hydroxide (Ca (OH) ₂ ), calcium oxide (CaO), sodium hydroxide (NaOH), potassium hydroxide (KOH), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), sodium carbonate (Na ₂ CO ₃ ) , Potassium carbonate (K ₂ CO ₃ ), lithium carbonate (Li ₂ CO ₃ ), calcium chloride (CaCl ₂ ) And calcium fluoride (CaF) may include at least one selected from the group consisting of, the content may be 0.05 to 0.5% by weight based on 100% by weight of the dry mixture.

The content of the hydroxyalkyl alkyl cellulose may be 0.1 to 1.0 parts by weight based on 100 parts by weight of the dry mixture.

The adhesive composition may further include at least one additive selected from the group consisting of starch, acrylic thickener and dispersant.

The content of the additive may be 0.1 to 50 parts by weight based on 100 parts by weight of the hydroxyalkyl alkyl cellulose.

In addition, the present invention provides an adhesive for ALC comprising the composition.

In this case, the porosity of the ALC may be 40% to 80%.

Adhesive composition for ALC according to the present invention has a high viscosity in the range of 10,000 ~ 100,000cps, at the same time hydroxyalkyl alkyl having an alkyl group substitution degree (DS) of 1.0 ~ 1.8, hydroxyalkyl group substitution degree (MS) of 0.2 ~ 1.2 By including cellulose, it is possible to provide an adhesive for ALC with improved water retention and adhesive strength.

Thus, according to the present invention, the problem of lowering the adhesive strength, which is caused by the moisture of the adhesive is lost to the pores of the ALC when the construction of the ALC can be solved. Therefore, the adhesive for ALC according to the present invention can be preferably used for the construction of various ALC products such as ALC blocks or ALC panels having a porosity of 40% to 80% as well as bricks or concrete which are generally used.

The present invention is a dry mixture comprising an inorganic binder and aggregate; And hydroxyalkyl alkyl cellulose having an alkyl group substitution degree (DS) of 1.0 to 1.8 and a hydroxyalkyl group substitution degree (MS) of 0.2 to 1.2; wherein the 2 wt% aqueous solution viscosity of the hydroxyalkyl alkyl cellulose is Brookfield It relates to an ALC adhesive composition and an ALC adhesive comprising the same, which is 10,000 to 100,000 cps when measured at 20 ° C. and 20 rpm with a viscometer.

The inorganic binder serves to enhance strength by combining aggregates, and may include cement and fillers. Preferably, the cement is portland cement as defined in KS L 5201, such as ordinary portland cement, medium heat portland cement, crude steel portland cement, low heat portland cement, sulfate resistant portland cement, and white portland cement as defined in KS L 5204, ply It may include at least one selected from the group consisting of ash ash (fly ash cement) and aluminum-containing cement, the filler may include at least one selected from the group consisting of limestone, quicklime, hydrated lime, lime powder and talc. In addition, hemihydrate gypsum, dolomite plaster, clay, and the like may be included in the inorganic binder.

As such, when the dry mixture according to the present invention includes cement and a filler, the dry mixture preferably includes 10 to 50 wt% of cement, 0.1 to 20 wt% of filler, and 30 to 70 wt% of aggregate.

When the content of the cement is less than 10% by weight, the ability of cement to aggregate aggregate significantly decreases, so the strength and durability may be lowered, whereas when the content of the cement exceeds 50% by weight, the price may increase and dry shrinkage may occur significantly. And, the filler is used to improve the durability while reducing the heat of cure, when the content is less than 0.1% by weight there is a fear that the amount of dry shrinkage of the cured body is increased, while the amount of the filler when it exceeds 20% by weight This excess may reduce fluidity and workability.

The aggregate is a skeleton in the adhesive composition for ALC, serves to improve the mechanical strength, and a solid and chemically stable should be used. As described above, the content of aggregate may be 30 to 70% by weight based on 100% by weight of the dry mixture, and if the content is less than 30% by weight, the mechanical strength may drop, whereas when the content exceeds 70% by weight, cement Since a relatively large amount is added compared to the aggregate there is a fear that the bonding strength of the aggregate and cement is lowered. As such aggregates, one or more selected from the group consisting of steel sand, mountain sand, silica sand, calcium carbonate and lightweight aggregates (eg, pearlite) may be used.

The dry mixture may further include at least one selected from the group consisting of reemulsifying powder resins and curing accelerators in addition to the binder and aggregate.

The re-emulsified powder resin is a material that has adhesive strength, flexural strength, and elasticity. The re-emulsifying powder resin may include at least one selected from the group consisting of ethylene-vinylacetate, acrylic latex, and styrene-butadiene rubber, and preferably may be ethylene-vinylacetate.

The content of the re-emulsified powder resin may be 1.0 to 10.0% by weight based on 100% by weight of the dry mixture, when the content of the powdered resin is less than 1.0% by weight there is a fear that sufficient adhesive strength and flexural strength may not be obtained. On the other hand, when it exceeds 10.0% by weight, there is a fear that the adhesive strength of the water drops.

The curing accelerator serves to increase the initial strength by promoting the hydration reaction, calcium hydroxide (Ca (OH) ₂ ), calcium oxide (CaO), sodium hydroxide (NaOH), potassium hydroxide (KOH), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), sodium carbonate (Na ₂ CO ₃ ), potassium carbonate (K ₂ CO ₃ ), lithium carbonate (Li ₂ CO ₃ ), calcium chloride (CaCl ₂ ) And calcium fluoride (CaF) may include one or more selected from the group consisting of.

The content of the curing accelerator may be 0.05 to 0.5% by weight based on 100% by weight of the dry mixture, if the content is less than 0.05% there is a fear that the initial strength is lowered, if more than 0.5% by weight open time There is a risk of falling.

On the other hand, the hydroxyalkyl alkyl cellulose is a kind of cellulose ether derived from cellulose which is a vegetable material, and is a cellulose derivative in which the hydroxyl group of cellulose is etherified using an etherifying agent.

The hydroxyalkyl alkyl cellulose used in the present invention is prepared by chemically adjusting the degree of substitution so as to be suitable for the ALC adhesive composition having high porosity. The degree of alkyl group substitution (DS) is 1.0 to 1.8 and the degree of hydroxyalkyl group substitution ( MS) is 0.2 to 1.2. In the present specification, the alkyl group substitution degree (DS) means an average number of hydroxyl groups substituted with an alkyl group per anhydroglucose unit, and the hydroxyalkyl group substitution degree (MS) means an average number of hydroxyl groups substituted with a hydroxyalkyl group per anhydroglucose unit. do. When the alkyl group substitution degree is high, hydrophobicity is high, and even when there are few hydroxyalkyl groups, hydrophobicity is high. Therefore, when the cellulose ether having an alkyl group substitution degree exceeding the upper limit or the hydroxyalkyl group substitution degree is lower than the lower limit is used, the water retention of the cellulose ether may be insufficient, resulting in poor workability of the adhesive for ALC containing the same. On the other hand, if the alkyl group substitution degree is less than the lower limit of the above range or the hydroxyalkyl group substitution degree exceeds the upper limit, there is a concern that the change in fluidity over time becomes large, and the necessary pot life is not obtained.

Specifically, the hydroxyalkyl alkyl cellulose may include at least one selected from the group consisting of hydroxypropyl methyl cellulose (HPMC) and hydroxyethyl methyl cellulose (HEMC).

The content of the hydroxyalkyl alkyl cellulose may be 0.1 to 1.0 parts by weight based on 100 parts by weight of the dry mixture. When the content of the hydroxyalkyl alkyl cellulose is less than 0.1 parts by weight, there is a fear that the water-retaining property of the adhesive for ALC is lowered, whereas the adhesive strength is lowered.

In addition, the viscosity of the aqueous solution of 2% by weight of the hydroxyalkyl alkyl cellulose used in the present invention is characterized in that 10,000 ~ 100,000cps when measured at 20 ℃ and 20rpm conditions with a Brookfield viscometer. When the viscosity of the hydroxyalkyl alkyl cellulose is less than 10,000 cps, water-soluble property and adhesive strength of the adhesive for ALC are lowered. On the other hand, when the viscosity of the hydroxyalkyl alkyl cellulose exceeds 100,000cps, the stickiness is severe, the problem of poor workability occurs, and the problem that the adhesive strength is lowered when adding the input amount of water to improve such problems Done.

Adhesive composition for ALC according to the present invention may include one or more additives selected from the group consisting of starch, acrylic thickener and dispersant as necessary. The amount of the additive may be appropriately adjusted according to the kind thereof, and preferably 0.1 to 50 parts by weight based on 100 parts by weight of the hydroxyalkyl alkyl cellulose.

The starch serves to improve the water retention and workable time of the adhesive for ALC, and may include one or more selected from the group consisting of general starch and modified starch. In addition, the content of the starch may be 0.1 to 50 parts by weight based on 100 parts by weight of the hydroxyalkyl alkyl cellulose, and if the content is less than 0.1 parts by weight, it is not preferable because the input effect is insignificant. There is a risk of falling.

The acrylic thickener is to improve the bonding strength between the inorganic powder in the adhesive composition for ALC and to improve the adhesive strength, the content of the acrylic thickener is 0.1 to 20 parts by weight based on 100 parts by weight of the hydroxyalkyl alkyl cellulose Can be. If the content of the acrylic thickener is less than 0.1 parts by weight, the effect is not good because the input is insignificant. If the content of the acrylic thickener exceeds 20 parts by weight, it is not preferable in terms of efficiency since the degree of increase in adhesion strength and strength is reduced.

The dispersant serves to improve workability by dispersing the constituent particles of the adhesive composition for ALC, and may include one or more selected from the group consisting of a high performance AE (air-entraining) reducer and a high performance reducer. In addition, the content of the dispersant may be 0.1 to 10 parts by weight with respect to 100 parts by weight of the hydroxyalkyl alkyl cellulose, if the content is less than 0.1 parts by weight is not preferred because the effect is negligible, if it exceeds 10 parts by weight mechanical strength There is a risk of falling.

On the other hand, the present invention provides an adhesive for ALC comprising the composition.

In this case, the porosity of the ALC may be 40 to 80%. In the present specification, porosity refers to porosity, and means a volume ratio of pores included in the brick with respect to the refractory brick volume.

In the case of ALC adhesive composition prepared according to the present invention, even when used in the construction of high porosity ALC as described above has a property of high water retention and high adhesive strength does not lose moisture, as well as general brick or concrete ALC It can be used very preferably as an adhesive.

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

Example 1

Back Cement (Easy Well Back Cement, Youngjin Housing Co., Ceramic Tile Cement, KSL 1592 Types) 36.0 wt%, Silica Sand (Kyungin Material, No.6) 60.0 wt%, Reemulsifying Powder Resin A dry mixture was prepared by dry mixing 1.0% by weight) and slaked lime (Chungmu Chemical, Ca (OH) ₂ ) 3.0% by weight.

Then, 0.2 parts by weight of hydroxypropyl methyl cellulose (Lotte Fine Chemicals, methyl group substitution degree (DS): 1.2, hydroxypropyl group substitution degree (MS): 0.4)) and 25 parts by weight of water were added to 100 parts by weight of the dry mixture. After kneading to prepare an adhesive for ALC. In this case, the viscosity of the aqueous solution of 2% by weight of hydroxypropyl methyl cellulose (HPMC) is 15,000 cps when measured at 20 ° C. and 20 rpm with a Brookfield viscometer.

Examples 2 to 5 and Comparative Examples 1 to 3

An adhesive for ALC was prepared in the same manner as in Example 1, except that the content, viscosity, and degree of substitution (DS, MS) of the HPMC were adjusted as described in Table 1 below.

<Evaluation Method>

1. Conservability

The water retention of the adhesive for ALC prepared according to Examples 1 to 5 and Comparative Examples 1 to 3 was measured according to EN 18555. Specifically, the mortar was vibrated using a mortar mixer, the mortar was placed on a stainless steel ring (d100mm) on a filter paper, and the mortar was filled with a mortar ring, and after 20 minutes, the filter paper was filled with a filter paper. The amount of water absorbed was measured, and water retention was calculated and listed in Table 1.

2. Adhesive strength

The adhesive strength of the adhesive for ALC prepared according to Examples 1 to 5 and Comparative Examples 1 to 3 was measured according to EN1348. Specifically, the grooves are formed using uneven trowels (saw blade size 6 mm x 6 mm) on a concrete plate of 40 cm x 40 cm area. Subsequently, the concrete plate was left to stand for 5 minutes, an ALC block (5cm x 5cm x 1cm) was attached to the concrete plate and left for 12 hours, and then the tensile adhesive strength of the blocks was measured using an adhesive strength tester (Xinjiang Precision Co., Ltd.). Measured. At this time, the adhesive strength for each of the five blocks for each example or comparative example was measured, except for the value of the standard deviation ± 20% of the average strength from the measured adhesive strength value, by calculating the average value of the remaining adhesive strength It is shown in Table 1 below.

3. Workability

When the operator applied the adhesive for ALC to the ALC block, the sensory evaluation of the degree of ease of trowel felt was evaluated and the result was evaluated by the 5-point method.

	HPMC (parts by weight)	Viscosity (cps)	DS	MS	Conservative (%)	Adhesion Strength (Mpa)	Workability (5-point method)
Example 1	0.2	15,000	1.2	0.4	93.1	1.05	4.5
Example 2	0.5	15,000	1.2	0.4	95.2	1.27	4.5
Example 3	1.0	15,000	1.2	0.4	96.7	1.42	4.0
Example 4	0.5	30,000	1.4	0.5	95.5	1.31	4.0
Example 5	0.5	60,000	1.4	0.5	95.1	1.38	4.5
Comparative Example 1	0.2	8,000	1.2	0.4	88.9	0.85	4.5
Comparative Example 2	0.4	15,000	0.8	0.4	93.2	0.72	4.0
Comparative Example 3	0.3 *	15,000	1.2	0	92.6	0.88	4.5

* However, in the case of Comparative Example 3, 0.3 parts by weight of methyl cellulose (manufactured by Lotte Fine Chemical) having hydroxypropyl group substitution degree of 0 and methyl group substitution degree of 1.2 was used instead of HPMC.

Looking at the Table 1, in the case of the ALC adhesive prepared according to Examples 1 to 5, compared to the ALC adhesive prepared according to Comparative Examples 1 to 3, the water retention and workability exhibits a similar or high level and excellent adhesive strength You can see that.

Specifically, in the case of the adhesive for ALC prepared according to Comparative Example 1 containing HPMC having a viscosity of 8000cps, Examples 1 to 3 including HPMC having the same substitution degree as the HPMC while the viscosity is in the range of 10,000 to 100,000cps It can be seen that the water retention and adhesive strength is lower than the adhesive for ALC.

In addition, in the case of the adhesive for ALC prepared according to Comparative Example 2 containing HPMC having a methyl group substitution degree (DS) of 0.8, the same viscosity and hydroxypropyl as the HPMC while the methyl group substitution degree (DS) is in the range of 1.0 to 1.8 Compared with Examples 1 to 3 including HPMC having group substitution degree (MS), the water retention shows a similar level but the adhesion strength was significantly lower.

And, in the case of the adhesive for ALC prepared according to Comparative Example 3 containing methyl cellulose having a hydroxypropyl group substitution degree (MS) of 0, the hydroxypropyl group substitution degree (MS) is in the range of 0.2 ~ 1.2 while the HPMC Compared with Examples 1 to 3 including HPMC having the same viscosity and methyl group substitution degree (DS) and it can be seen that both water-retaining and adhesive strength is inferior.

As described above, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to explain the present invention, and the scope of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto. Should be construed as being included in the scope of the present invention.

Claims (9)

1. Dry mixtures comprising inorganic binders and aggregates; And

   Hydroxyalkyl alkyl cellulose having an alkyl group substitution degree (DS) of 1.0 to 1.8 and a hydroxyalkyl group substitution degree (MS) of 0.2 to 1.2;

   2% by weight aqueous solution viscosity of the hydroxyalkyl alkyl cellulose is an adhesive composition for lightweight foam concrete, characterized in that 10,000 ~ 100,000cps when measured at 20 ℃ and 20rpm conditions with a Brookfield viscometer.
2. The method of claim 1,

   The dry mixture is a lightweight foamed concrete adhesive composition, characterized in that it further comprises at least one selected from the group consisting of re-emulsified powder resin and a curing accelerator.
3. The method of claim 2,

   The re-emulsifying powder resin includes at least one selected from the group consisting of ethylene-vinylacetate, acrylic latex and styrene-butadiene rubber, the content of which is 0.1 to 10.0% by weight based on 100% by weight of the dry mixture. Adhesive composition for lightweight foamed concrete.
4. The method of claim 2,

   The curing accelerator is calcium hydroxide (Ca (OH) ₂ ), calcium oxide (CaO), sodium hydroxide (NaOH), potassium hydroxide (KOH), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), sodium carbonate (Na ₂ CO ₃ ) , Potassium carbonate (K ₂ CO ₃ ), lithium carbonate (Li ₂ CO ₃ ), calcium chloride (CaCl ₂ ) And calcium fluoride (CaF) comprises at least one selected from the group consisting of, the content of the adhesive composition for lightweight foam concrete, characterized in that 0.05 to 0.5% by weight based on 100% by weight of the dry mixture.
5. The method of claim 1,

   The content of the hydroxyalkyl alkyl cellulose is an adhesive composition for lightweight foam concrete, characterized in that 0.1 to 1.0 parts by weight based on 100 parts by weight of the dry mixture.
6. The method of claim 1,

   The adhesive composition is an adhesive composition for lightweight foam concrete, characterized in that it further comprises at least one additive selected from the group consisting of starch, acrylic thickener and dispersant.
7. The method of claim 6,

   The content of the additive is an adhesive composition for lightweight foam concrete, characterized in that 0.1 to 50 parts by weight based on 100 parts by weight of the hydroxyalkyl alkyl cellulose.
8. Adhesive for lightweight foam concrete, comprising the adhesive composition for lightweight foam concrete according to any one of claims 1 to 7.
9. The method of claim 8,

   Porosity of the lightweight foam concrete adhesive for light-weight foam concrete, characterized in that 40% ~ 80%.