KR100950504B1 - Additive for lightweight joint compounds with suppressed bubble generation and method for preparing the same - Google Patents

Abstract

Disclosed are additives for lightweight joint compounds and methods of making the same. The disclosed lightweight joint compound additive is characterized in that it comprises a hydroxyalkylalkyl cellulose having an alkyl group substitution degree (DS) of 1.38 to 1.78 and a hydroxyalkyl group substitution degree (MS) of 0.38 to 0.5.

Therefore, the disclosed lightweight joint compound additive and its manufacturing method can improve the water retention and adhesion while suppressing the bubble generation of the lightweight joint compound, it is possible to ensure the uniformity and fine appearance of the product.

Description

Additive for lightweight joint compounds with suppressed bubble generation and method for preparing the same}

The present invention relates to an additive for a lightweight joint compound and a method for manufacturing the same, and more particularly, to an additive for a lightweight joint compound and a method for producing the same, which can improve water retention and adhesion while suppressing bubble generation of the lightweight joint compound.

Joint compound (or tape joint compound) is a solid paste that is used to fill gaps between one wallboard and another wallboard and to bond them together in building construction.

In the wall finishing work using the joint compound, the gap between the wall plates is first filled with the joint compound, and the tape tape is attached to the joint compound to prevent the cracking thereof, and then the joint compound is additionally filled on the paper tape for finishing. After drying, the surface is treated with a flat surface. The final finish is achieved by applying wallpaper or painting with paint.

These joint compounds generally consist of calcium carbonate, clay, mica, perlite, cellulose ethers, latex or gypsum, and water, among which thickeners include cellulose ethers and clays. ) Can be used.

U.S. Patent No. 4,657,594 discloses a lightweight joint compound comprising a filler, a non-leveling agent, expanded perlite treated with an amino functional silicone compound, a thickening agent, a binder, and water. have.

US 2005/0235878 A1 discloses changes in water retention, flow resistance and workability depending on the type of cellulose ether thickener applied to the joint compound. In particular, the patent discloses a change in viscosity, resistance to cracks, and workability according to the type and content of cellulose ether in the lightweight joint compound.

Methocel J75MS or Mecellose PMH 9860, which is mainly used in the past, is known to have good compatibility with pearlite in a light weight joint compound, and thus, workability and water retention are relatively good. However, in this case, since the foam is excessive in the manufacturing process and the product becomes bulky, an additional antifoaming agent must be added, and when an excessive amount of the antifoaming agent is added, the specific gravity is changed by the antifoaming agent and stability as a lightweight product is not secured. There is this. That is, Methocel J75MS or Mecellose PMH 9860 is equipped with a higher content of hydroxypropyl group than other methyl hydroxypropyl cellulose (MHPC), and thus has good compatibility with the pearlite, which is a light weight raw material, but has a surface activity of cellulose. Since the ability to increase the ability to generate a large amount of bubbles during the manufacturing process there is a problem that the occurrence of cracks (crater) and craters (crater) phenomenon after the joint compound work. In addition, due to the use of expanded pearlite, the adhesion strength is low, the content of the emulsion binder must be increased, and the water retention is low, so the content of the cellulose thickener must be increased, so there is a problem in that the economic efficiency is lowered.

It is an object of the present invention to provide an additive and a method for producing the same, which are added to the lightweight joint compound and can suppress the generation of bubbles thereof while improving water retention and adhesion.

Another object of the present invention is to provide an additive and a method of manufacturing the same, which are added to the lightweight joint compound to prevent fine cracking and fine crater formation thereof, thereby ensuring uniformity and fine appearance of the product.

The present invention to solve the above problems,

Provided are additives for lightweight joint compounds comprising hydroxyalkylalkyl celluloses having an alkyl group substitution degree (DS) of 1.38 to 1.78 and a hydroxyalkyl group substitution degree (MS) of 0.38 to 0.59.

According to one embodiment of the present invention, when the hydroxyalkylalkyl cellulose is prepared in 2 (w / v)% aqueous solution and the viscosity of the aqueous solution is measured at 20 ° C. and 20 rpm with a Brookfield viscometer, the value is 10,000 ~ 50,000cps

According to another embodiment of the invention, the hydroxyalkylalkyl cellulose comprises hydroxypropylmethyl cellulose.

In addition, the present invention to solve the above problems,

It provides a lightweight joint compound comprising an additive according to any one of the above embodiments.

In addition, the present invention to solve the above problems,

In the method for producing an additive for lightweight joint compound containing hydroxyalkylalkyl cellulose,

The hydroxyalkylalkyl cellulose has an alkyl group substitution degree (DS) of 1.19 to 1.41 and a hydroxyalkyl group substitution degree (MS) of 0.47 to 0.64 of hydroxyalkylalkyl cellulose (A) and an alkyl group substitution degree (DS) of 1.40 to 1.99. And a hydroxyalkylalkyl cellulose (B) having a hydroxyalkyl group substitution degree (MS) of 0.13 to 0.27, wherein the alkyl group substitution degree (DS) is 1.38 to 1.78 and the hydroxyalkyl group substitution degree (MS) is 0.38. It provides a method for producing an additive for lightweight joint compounds, comprising hydroxyalkylalkyl cellulose (C) of ˜0.59.

According to one embodiment of the invention,

The hydroxyalkylalkyl celluloses (A), (B), and (C) were each prepared in an aqueous solution of 2 (w / v)%, and the viscosity of each of the aqueous solutions was measured at 20 ° C and 20 rpm with a Brookfield viscometer. In this case, the viscosity of the aqueous solution of hydroxyalkylalkyl cellulose (A) is 10,000 ~ 50,000 cps, the viscosity of the aqueous solution of hydroxyalkylalkyl cellulose (B) is 1,000 ~ 10,000cps, the aqueous solution of hydroxyalkylalkyl cellulose (C) The viscosity of is 10,000 ~ 50,000 cps.

According to another embodiment of the invention,

The said hydroxyalkylalkyl cellulose (A) :( B) is mixed in the ratio of 80: 20-40: 60 on a molar ratio basis.

According to another embodiment of the invention,

At least one of the hydroxyalkylalkyl celluloses (A) and (B) contains hydroxypropylmethyl cellulose.

According to the present invention, an additive and a method of manufacturing the same may be provided that are added to the lightweight joint compound to suppress bubble generation thereof and improve water retention and adhesion.

In addition, according to the present invention, an additive and a method for manufacturing the same may be provided that are added to the lightweight joint compound to prevent fine cracking and formation of fine craters in advance, thereby ensuring uniformity and fine appearance of the product.

Hereinafter, a preferred embodiment of the present invention will be described in detail.

The additive for the lightweight joint compound according to one embodiment of the present invention has an alkyl group substitution degree (DS) of 1.38 to 1.78, particularly 1.38 to 1.48, and a hydroxyalkyl group substitution degree (MS) of 0.38 to 0.59, particularly 0.38 to 0.44. Oxyalkylalkyl celluloses. By using hydroxyalkylalkyl cellulose having a substitution degree range of such an alkyl group and a hydroxyalkyl group as an additive, the lightweight joint compound can improve water retention and adhesion while suppressing bubble generation, which will be described in detail later. When the hydroxyalkylalkyl cellulose is hydroxypropylmethyl cellulose, the methyl group substitution degree (DS) and the hydroxypropyl group substitution degree (MS) may be calculated by the following Equations 1 and 2, respectively.

When the hydroxyalkylalkyl cellulose is prepared in a 2 (w / v)% aqueous solution and the viscosity of the aqueous solution is measured at 20 ° C. and 20 rpm with a Brookfield viscometer, the value is preferably 10,000 to 50,000 cps. If the viscosity is less than 10,000 cps, the viscosity of the joint compound is too low to increase the input amount, so it is not economically desirable, and if it exceeds 50,000 cps, water retention is weakened, which is not preferable.

In addition, the hydroxyalkylalkyl cellulose is preferably hydroxypropylmethyl cellulose or include the same, but the present invention is not limited thereto.

In addition, the hydroxyalkylalkyl cellulose may be prepared by the following method. That is, the hydroxyalkylalkyl cellulose has a hydroxyalkylalkyl cellulose (A) having an alkyl group substitution degree (DS) of 1.19 to 1.41 and a hydroxyalkyl group substitution degree (MS) of 0.47 to 0.64, and an alkyl group substitution degree (DS) of It may be prepared by mixing a hydroxyalkylalkyl cellulose (B) having a 1.40 to 1.99 and a hydroxyalkyl group substitution degree (MS) of 0.13 to 0.27.

In this case, when the hydroxyalkylalkyl celluloses (A) and (B) were each prepared in 2 (w / v)% aqueous solution, and the viscosity of each of the aqueous solutions was measured at 20 ° C and 20 rpm with a Brookfield viscometer, It is preferable that the viscosity of the said hydroxyalkylalkyl cellulose (A) aqueous solution is 10,000-50,000cps, and the viscosity of the said hydroxyalkylalkyl cellulose (B) aqueous solution is 1,000-10,000cps. When the viscosity of each of the aqueous solution is out of the respective ranges, it is not preferable because the viscosity and water retention of the joint compound are lowered.

It is preferable that the said hydroxyalkylalkyl cellulose (A) :( B) is mixed in the ratio of 80: 20-40: 60 on a molar ratio basis. When the mixing ratio is out of the above range, the viscosity and uniformity of the joint compound are lowered, which is not preferable.

In addition, it is preferable that at least one of the hydroxyalkylalkyl celluloses (A) and (B), in particular, both are or include hydroxypropylmethyl cellulose, but the present invention is not limited thereto.

Hereinafter, the manufacturing method of the said hydroxyalkylalkyl cellulose (A) and (B) is explained in full detail.

First, the manufacturing method of hydroxyalkylalkyl cellulose (A) is demonstrated.

First, finely ground cellulose (for example, natural pulp) is introduced into a high pressure reactor. Subsequently, alkali metal hydroxide is evenly sprayed on the cellulose through the spray nozzle so that the cellulose can easily react with the etherification agent described later. Here, the alkali metal hydroxide is used to weaken the hard crystalline structure of the cellulose, and an alkali metal hydroxide in a solid state or an aqueous solution state may be used. Specifically, the alkali metal hydroxide binds to cellulose and expands its crystal structure so that the hydroxyl group in the cellulose is completely exposed out of the crystal structure, whereby various chemicals bind or react with the cellulose through the exposed hydroxyl group. To help. As the alkali metal hydroxide, sodium hydroxide, potassium hydroxide, and / or lithium hydroxide may be used.

In addition, it is preferable that the usage-amount of the said alkali metal hydroxide is 0.5-4 mol per mole of cellulose, especially 0.8-1.5 mol. When the amount is less than 0.5 mole per mole of cellulose, the crystal structure of the cellulose is not weakened to a sufficient extent to react with the etherification agent, so that not only the desired degree of substitution can be obtained, but also the yield is lowered. Due to the excessive content of the metal hydroxide, since the etherification agent reacts with cellulose to produce hydroxyalkylalkyl cellulose, the amount of side reaction products such as polypropylene glycol is increased, resulting in lower substitution and lower yields. .

When injecting the alkali metal hydroxide to the hydroxyalkylalkyl cellulose (A) as described above, it is preferable to maintain the temperature of the reactor at 15 ~ 60 ℃, and also to distribute the alkali metal hydroxide evenly in the cellulose It is important to spray.

After the alkali metal hydroxide injection, the mixture is stirred for a certain period of time so that the cellulose is in a good state to bind with the etherification agent. Subsequently, diluent gas is added to the reactor and mixed evenly with stirring for about 10 minutes to 1 hour to allow the cellulose to react uniformly with the etherification agent. The diluent gas is not particularly limited, and a gas containing 65 to 95 parts by weight of a dialkyl ether and 5 to 35 parts by weight of a gas selected from methyl chloride, ethyl chloride, propyl chloride and the like can be preferably used. The diluent gas is added to combine with cellulose to obtain the desired degree of substitution (DS).

Subsequently, the total amount of etherification agent (a) was added to the reactor at once in a ratio of 0.3 to 1.5 mol, more preferably 0.4 to 1.2 mol, per mol of the alkali metal hydroxide, depending on the degree of substitution desired. The etherification agent (a) is bonded to the cellulose by reacting at 60 ° C., preferably 60 ° C. to 90 ° C. If the amount of the etherification agent (a) is less than 0.3 mol per mol of the alkali metal hydroxide or exceeds 1.5 mol, it is not preferable to obtain an appropriate degree of substitution. As the etherification agent (a), an alkylene oxide or the like may be used. As the alkylene oxide, an alkylene group having 2 to 5 carbon atoms is generally used. Preferably, propylene oxide and / or ethylene oxide may be used. have.

The etherification reaction time is 30 minutes to 2 hours, preferably 45 minutes to 1.5 hours.

Next, an etherification agent (b) is added to the reactor at a rate of 1 to 2.5 moles per 1 mole of the cellulose, and reacted at 50 to 120 ° C., more preferably at 70 to 100 ° C. for about 1 hour to obtain a desired degree of substitution. The hydroxyalkyl alkyl cellulose (A) which has is obtained. When the usage-amount of the said etherification agent (b) is less than 1 mol per mol of cellulose, and when it exceeds 2.5 mol, it is difficult to obtain suitable substitution degree, and it is unpreferable. Alkyl halide or the like may be used as the etherification agent (b), and preferably methyl chloride may be used.

On the other hand, hydroxyalkylalkyl cellulose (B) maintains the amount of the etherification agent (a) at 0.3 to 1.5 mol per mol of the alkali metal hydroxide and the amount of the etherification agent (b) at 0.2 to 0.8 mol per mol of cellulose. Except having changed, it is manufactured by the same method as the manufacturing method of the said hydroxyalkylalkyl cellulose (A).

Each of the hydroxyalkylalkyl celluloses (A) and (B) prepared as described above has a difference in physical properties depending on the range of substitution.

On the other hand, the present invention provides an additive comprising a hydroxyalkylalkyl cellulose having an alkyl group substitution degree DS of 1.38 to 1.78 and a hydroxyalkyl group substitution degree of 0.28 to 0.59, and a lightweight joint compound including the additive.

 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

Preparation Example 1: Preparation of hydroxypropylmethyl cellulose (A)

Finely ground natural pulp was added to a horizontal / vertical stirred high pressure reactor with a volume of 5 L. The reactor was then maintained at a temperature of 20 ° C. and 50% by weight aqueous sodium hydroxide solution was evenly injected into the pulp through the spray nozzle while stirring the contents. At this time, the injection amount of the aqueous sodium hydroxide solution was adjusted so that the total molar ratio of the injected pulp: sodium hydroxide was 1: 3.6. Next, 5.3 kg of a mixed gas composed of 95% by weight of dimethyl ether and 5% by weight of methyl chloride was added to the reactor as a diluent gas. Subsequently, methyl chloride was added to the reactor at a rate of 1.1 mol per mol of sodium hydroxide, and a total amount of propylene oxide was added at a rate of 1.1 mol per mol of pulp at once, followed by stirring well. Subsequently, the reactor temperature was raised to 90 ° C. for 50 minutes, and then the reaction proceeded at 90 ° C. for 50 minutes. At this time, the reactor pressure was maintained at 10 kg / cm 2 or less. Next, hydroxypropylmethyl cellulose (A) was obtained by releasing the reactor pressure when the reaction was completed and then filtering and drying the mixed solution of the reactor using boiling water.

Preparation Example 2 Preparation of Hydroxypropylmethyl Cellulose (B)

Hydroxypropylmethyl cellulose was prepared in the same manner as in Preparation Example 1, except that methyl chloride was added at a rate of 1.07 mol per 1 mol of sodium hydroxide and 0.4 mol per 1 mol of pulp. (B) was prepared.

Example 1-1 Preparation of Hydroxypropylmethyl Cellulose Used as Additive for Lightweight Joint Compounds

Hydroxypropylmethyl cellulose (A) and (B) prepared in Preparation Examples 1 and 2, respectively, were mixed in a ratio of 3: 1 on a molar ratio basis, followed by stirring to form hydroxypropylmethyl cellulose used as an additive for lightweight joint compound. Got.

Example 1-2 and Example 1-3

Hydroxypropylmethyl cellulose was prepared in the same manner as in Example 1-1 except that the amount of methyl chloride or propylene oxide was changed as shown in Table 1 below.

Comparative Example 1-1 to 1-3

In Comparative Examples 1-1 to 1-3, as hydroxypropylmethyl cellulose used as an additive for a joint compound, hydroxypropylmethyl cellulose prepared in each of Examples 1-1 to 1-3 as shown in Table 1 below. ) Only.

Evaluation example 1-1: substitution degree and viscosity measurement

Gas chromatography and hydroxypropyl group substitution degree of hydroxypropylmethyl cellulose used as the additive for lightweight joint compounds obtained in Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-3 It was measured by the method. In addition, the hydroxypropyl methyl cellulose was prepared in an aqueous solution of 2 (w / v)%, and the viscosity of the aqueous solution was measured at 20 ° C. and 20 rpm with a Brookfield viscometer, and the results are shown in Table 2 below.

Referring to Table 2, it can be seen that the degree of methyl group substitution and the degree of hydroxypropyl group substitution vary depending on the molar ratio of hydroxypropylmethyl cellulose (A): hydroxypropylmethyl cellulose (B). Taken together, in Examples 1-1 to 1-3, methyl group substitution degree (DS) and hydroxypropyl group substitution degree (MS) are in the ranges of 1.38 to 1.78 and 0.38 to 0.59, respectively, and Comparative Example 1- In the case of 1 to 1-3, it can be seen that at least one of the methyl group substitution degree and the hydroxypropyl group substitution degree is out of the above range.

Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-3: Preparation of Lightweight Joint Compound

0.8 g of each of hydroxypropylmethyl cellulose used as an additive for lightweight joint compounds prepared in Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-3 (0.5% by weight, based on the total weight of the lightweight joint compound, In the same standard), calcium carbonate (average particle diameter: 18 μm) 79 g (49.4 wt%), clay (tatapulgite) 5.0 g (3.1 wt%), perlite 7.6 g (4.8 wt%), latex (latex) Light weight compound was prepared by mixing 3.8 g (2.4 wt%) of A526BP), 0.3 g (0.2 wt%) of preservatives (Troy San), and 64.0 g (40.0 wt%) of water.

Evaluation example 2-1: measurement of bubble generation amount, tape adhesion, and water retention

The physical properties of the lightweight joint compounds prepared in Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-3 were evaluated as follows.

First, the bubble generation amount of the lightweight joint compound can be calculated by the following equation (3). Specifically, the actual specific gravity (hereinafter referred to as actual gravity) was measured by using a specific gravity cup having a volume of 500 ml immediately after manufacturing each of the lightweight joint compounds, and based on this, as a difference from the true specific gravity when no bubbles existed. The content of each prepared lightweight joint compound was calculated. The specific gravity was measured by ASTM C135-96 (2003, Standard Test Method for True Specific Gravity of Refractory Materials by Water Immersion).

In addition, by measuring the change in the bubble content according to the stirring time for each manufactured lightweight joint compound to determine the degree of bubble generation.

% Bubble generation = (1- actual weight / true weight) * 100

In addition, the water retention of the lightweight joint compound was measured as follows according to DIN 18555. That is, a ring having a height of 1 cm and an inner diameter of 5 cm was placed on the dried paper, and then left on the paper in the ring for 30 minutes with an amount of the light weight compound compound corresponding to the inner volume of the ring. Thereafter, the weight of the water absorbed by the paper was measured. Conservativeness was calculated by the following equation (4).

Water retention (wt%) = (Wo-Wp) / Wo × 100

Where Wo is initially the weight of water contained in the lightweight joint compound, and Wp is the weight of water absorbed by the paper.

In addition, the tape adhesion of the light weight joint compound was measured as follows based on ASTM 474-67 method. That is, a lightweight joint compound was applied on a gypsum board to a thickness of 1/8 "(3.18mm), a tape cut to 24 cm x 5 cm was placed thereon, the tape was rubbed three times with Rowel, and dried for 22 hours. Then, the ratio which divided the area of the tape which adhered to the lightweight joint compound by the area of the whole tape, did not fall when peeling off the said tape by hand, and made tape adhesiveness.

Referring to Table 3 above, the methyl group substitution degree (DS) and the hydroxypropyl group substitution degree (MS) of the hydroxypropylmethyl cellulose used were in the ranges of 1.38 to 1.78 and 0.38 to 0.59, respectively. When comparing -3 and Comparative Examples 2-1 to 2-2 outside of any one of the above ranges of each substitution degree, the case of Examples 2-1 and 2-2 has a higher bubble generation suppression ability. In the case of Example 2-3, when compared with Comparative Example 2-3, the initial content is high, but the content of the content according to the stirring time is small, the content after 10 minutes can be seen to be relatively low have.

It can be confirmed that Examples 2-1 to 2-3 have better tape adhesion than Comparative Examples 2-1 to 2-3. When only one type of hydroxypropylmethyl cellulose was used as in Comparative Examples 2-1 to 2-3, the bubble generation amount was relatively high, the water retention was relatively low, and the adhesion was low.

Additives for lightweight joint compounds and hydroxyalkylalkyl cellulose comprising a hydroxyalkylalkyl cellulose according to the present invention having the configuration as described above, by using a hydroxyalkylalkyl cellulose having a degree of substitution different from the prior art, conventional hydroxy In the case of using an alkylalkyl cellulose, while overcoming a large amount of bubble generation problems that could not be solved at all, excellent water retention was secured, and an effect of significantly improving tape adhesion was obtained.

Therefore, the lightweight joint compound according to the present invention has the advantage of ensuring uniformity and fine appearance of the product because the amount of bubbles generated is reduced to prevent fine cracking and fine crater formation in advance.

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. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (8)

delete delete delete delete In the method for producing an additive for lightweight joint compound containing hydroxyalkylalkyl cellulose, The hydroxyalkylalkyl cellulose has a hydroxyalkylalkyl cellulose (A) and an alkyl group substitution degree (DS) having an alkyl group substitution degree (DS) of 1.19 to 1.41 and a hydroxyalkyl group substitution degree (MS) of 0.47 to 0.64. It is prepared by mixing hydroxyalkylalkyl cellulose (B) having 1.99 and hydroxyalkyl group substitution degree (MS) of 0.13 to 0.27, wherein the alkyl group substitution degree (DS) is 1.38 to 1.78 and the hydroxyalkyl group substitution degree (MS) is It contains hydroxyalkylalkyl cellulose (C) which is 0.38-0.59, Mixing ratio of the said hydroxyalkylalkyl cellulose (A) :( B) is 80: 20-40: 60 on a molar ratio basis, The manufacturing method of the additive for lightweight joint compounds. The method of claim 5, The hydroxyalkylalkyl celluloses (A), (B), and (C) were each prepared in an aqueous solution of 2 (w / v)%, and the viscosity of each of the aqueous solutions was measured at 20 ° C and 20 rpm with a Brookfield viscometer. In this case, the viscosity of the aqueous solution of hydroxyalkylalkyl cellulose (A) is 10,000 ~ 50,000 cps, the viscosity of the aqueous solution of hydroxyalkylalkyl cellulose (B) is 1,000 ~ 10,000cps, the aqueous solution of hydroxyalkylalkyl cellulose (C) The viscosity is 10,000 ~ 50,000 cps manufacturing method of the additive for lightweight joint compound, characterized in that. delete The method of claim 5, At least one of the hydroxyalkylalkyl celluloses (A) and (B) comprises a hydroxypropylmethyl cellulose, a method for producing an additive for lightweight joint compound.