CA2039124C - High productivity joint compound - Google Patents
High productivity joint compound Download PDFInfo
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- CA2039124C CA2039124C CA 2039124 CA2039124A CA2039124C CA 2039124 C CA2039124 C CA 2039124C CA 2039124 CA2039124 CA 2039124 CA 2039124 A CA2039124 A CA 2039124A CA 2039124 C CA2039124 C CA 2039124C
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Abstract
Joint compounds suitable for use with plaster wallboard are disclosed wherein the use of an aqueous suspension of a nonionic cellulose ether such as hydroxyethylcellulose in an inorganic salt as the thickener result in much shorter mixing times, higher production rates and improved joint compound properties.
Description
This invention relates to compositions containing a thickener which are useful as joint sealing materials for the installation of wallboard paneling. More specifically, it relates to compositions wherein the thickener is an aqueous suspension of a cellulose ether in an inorganic salt.
For many years, the use of wallboard has all but displaced plaster in erection of interior walls in the construction of buildings. Wallboard is generally installed in large panels which are nailed and glued to the studding of the wall and fitted together until the entire section of wall is covered. The joints where sections of the board are butted together are covered with joint compound, then with tape and then the taped joints and all nails are covered with a joint compound which, upon hardening, can be sanded smooth so that it is imperceptible under paint or wallpaper.
Joint compounds employed with wallboard contain a resinous binder, limestone, clay, mica, lubricant, stabilizer and a thickener as the principal dry ingredients which are mixed with water to form a dope which is applied normally by troweling, as described in U.S. Patent 3,891,582.
Typically, the water-soluble polymer used to thicken the product joint compound is a cellulose ether, e.g., hydroxyethylcellulose, hydroxypropylmethyl cellulose, etc. One of the factors limiting the output of 20391 24~
large quantities of a joint compound in a commercial plant is the relatively long time necessary to completely dissolve the water-soluble polymer thickener. Because of this, the ingredients are usually blended for times ranging from 15 to 20 minutes. The water-soluble polymer may be dry-blended with the other ingredients, or added as an aqueous slurry. In the latter case, the hydration rate of the water-soluble polymer must be chemically retarded so that the slurry does not thicken prior to being added to the remaining ingredients.
It is the object of this invention to provide a new aqueous joint compound formulation, and a process for its preparation. One of the advantages of this new formulation is that it reduces the time needed to blend all of the joint compound ingredients into a homogeneous, ready-to-use joint compound formulation to as little as about 5 minutes, resulting in considerable cost savings and convenience for the user. This is accomplished by preparing the water soluble polymer thickener in fluidized suspension form and adding it directly to the mixture of other joint compound ingredients. It is not necessary to chemically retard the hydration rate of the water soluble polymer thickener.
An aqueous joint compound formulation comprises calcium carbonate, clay, binder, mica. clay lubricant and thickener, characterized in that the thickener is an aqueous suspension of a nonionic cellulose ether in an inorganic salt, wherein the suspension consists of 15% or more by weight of the cellulose ether based on the total weight of the suspension and the weight ratio of the inorganic salt to water in the suspension is at least 0.15.
For many years, the use of wallboard has all but displaced plaster in erection of interior walls in the construction of buildings. Wallboard is generally installed in large panels which are nailed and glued to the studding of the wall and fitted together until the entire section of wall is covered. The joints where sections of the board are butted together are covered with joint compound, then with tape and then the taped joints and all nails are covered with a joint compound which, upon hardening, can be sanded smooth so that it is imperceptible under paint or wallpaper.
Joint compounds employed with wallboard contain a resinous binder, limestone, clay, mica, lubricant, stabilizer and a thickener as the principal dry ingredients which are mixed with water to form a dope which is applied normally by troweling, as described in U.S. Patent 3,891,582.
Typically, the water-soluble polymer used to thicken the product joint compound is a cellulose ether, e.g., hydroxyethylcellulose, hydroxypropylmethyl cellulose, etc. One of the factors limiting the output of 20391 24~
large quantities of a joint compound in a commercial plant is the relatively long time necessary to completely dissolve the water-soluble polymer thickener. Because of this, the ingredients are usually blended for times ranging from 15 to 20 minutes. The water-soluble polymer may be dry-blended with the other ingredients, or added as an aqueous slurry. In the latter case, the hydration rate of the water-soluble polymer must be chemically retarded so that the slurry does not thicken prior to being added to the remaining ingredients.
It is the object of this invention to provide a new aqueous joint compound formulation, and a process for its preparation. One of the advantages of this new formulation is that it reduces the time needed to blend all of the joint compound ingredients into a homogeneous, ready-to-use joint compound formulation to as little as about 5 minutes, resulting in considerable cost savings and convenience for the user. This is accomplished by preparing the water soluble polymer thickener in fluidized suspension form and adding it directly to the mixture of other joint compound ingredients. It is not necessary to chemically retard the hydration rate of the water soluble polymer thickener.
An aqueous joint compound formulation comprises calcium carbonate, clay, binder, mica. clay lubricant and thickener, characterized in that the thickener is an aqueous suspension of a nonionic cellulose ether in an inorganic salt, wherein the suspension consists of 15% or more by weight of the cellulose ether based on the total weight of the suspension and the weight ratio of the inorganic salt to water in the suspension is at least 0.15.
Fluidized Suspension of P
The stable fluidized suspension of the nonionic thickener comprises 15% or more, by total weight, of a nonionic water soluble polymer dispersed in a aqueous solution of an inorganic salt preferably having a multivalent anion, wherein the weight ratio of the inorganic salt to the water is at least 0.15. Its composition and preparation are described in U.S. Patents 4,883,536 and 4,883,537.
For the thickener, useful water soluble polymers are nonionic and contain hydrophilic substituents such as hydroxyl. Illustrative are hydroxyethylcellulose, hydrophobically modified hydroxyethylcellulose, hydroxypropylcellulose, methyl hydroxypropylcellulose, and hydroxyethyl hydroxypropylcellulose. U.S. Patents 4,338,277, 4,243,802 and 4,826,970 describe some suitable hydrophobically modified cellulosics~.
The concentration of water soluble polymer in the aqueous suspension added as the thickener will be 15% or more. Preferably, the concentration will be in the range of 17 to 50%, and more preferably in the range of 20 to 35%.
Any inorganic salt which may be dissolved in water to a sufficiently high concentration that it will render the water-soluble polymer insoluble with minimal swelling, can be used in this invention. Suitable inorganic salts are diammonium sulfate (also known as ammonium sulfate), diammonium phosphate, ammonium polyphosphate, potassium carbonate, epsom salts (magnesium sulfate hydrate), sodium formate and mixtures thereof.
The weight ratio of inorganic salt to the water in the suspension is at least 0.15 and is preferably 0.18 to 0.6. The desired concentration of salt in water varies with the polymer to be suspended. For hydroxyethylcellulose, a salt to water ratio of 0.18 to 0.25 is preferred.
A number of other additives have been found to provide beneficial properties to the fluidized suspension. Preferred additives are stabilizers, such as hydrophilic fumed silica, and clays such as attapulgite clay. They increase the time over which the suspension will remain stable. Also useful for stabilization, in certain circumstances, are carboxymethylcellulose (CMC), xanthan gum and other water-soluble polymers. For instance, the most preferred stabilizers for hydroxyethyl cellulose suspensions are sodium carboxymethyl cellulose and xanthan gum. Stabilizers are generally used in amounts up to about 2%, and are preferably used in an amount of 0.2% to 1%, by weight of total suspension.
Other additives which can be used include pigments, dispersants, surfactants, glycols and thickening agents.
These are generally used in amounts up to 10%. preferably 0.5% to 2%, by weight of the total suspension.
The fluidized suspensions can be prepared by dissolving the inorganic salt in water to form an aqueous salt solution and, then, dispersing with agitation the water-soluble polymer therein. In the case where other additives are employed, these are typically added to the water before the salt. The slurry may comprise a blend of one or more of hydroxyethylcellulose (HEC), methylhydroxypropylcellulose (MHPC) and hydrophobically 20391 2~
modified hydroxyethylcellulose (HMHEC) or other similar modified cellulosic polymers.
Joint Compound Most commercial joint compound formulations contain limestone, clay, mica, resinous binder, thickener, lubricant and stabilizer in varying amounts. In some cases, other additives are included to give the composition sufficient body for application to a vertical wall without sagging or melt down. Materials useful for this purpose include, e.g., cellulose fibers in various forms, treated clays, and porous stone flour. When structure additives of this type are added, they normally replace a portion of the inert fillers, i.e., the limestone, mica or clay.
The resinous binder is normally a coalescable vinyl material, such as polyvinyl acetate) which upon drying or curing of the cement forms a thin matrix to hold the clay, limestone, etc. When a fully formulated mix is being prepared, the binder is usually added as an aqueous latex. In the case of dry mixes it is added as spray-dried latex particles. Other materials useful as the binder include, e.g., starch, casein, polyacrylamide, copolymers of acrylamide and acrylic acid.
In addition to the principal ingredients mentioned above, a typical joint compound will frequently also contain a dispersant, a defoamer, and a preservative.
Typically, joint compounds are prepared by combining all of the wet ingredients (and K2C03, if used) and mixing for one minute to homogenize. A blend of all the solids is then added to the mixing bowl, with continuing mixing. The entire mass is blended for a total of about 20 minutes. This procedure may be modified by different manufacturers.
Mixing time cannot simply be shortened in order to increase production. For example, with only 10 minutes mixing, a slightly pasty mixture results. and adhesion suffers. However, the use of a fluidized suspension of the water soluble thickener, as described in this invention, results in easy dispersion throughout the mixture, and faster hydration of the thickener.
Consequently, the mixing time is shortened to about 5 minutes and the production rate is 2 to 3 times that of the usual output.
r The following general procedure was employed to mix the ingredients:
(1) Add all of the liquid ingredients (and K2C03) to the mixing bowl and mix for one minute to obtain a uniform dispersion.
(2) Dry blend the limestone, clay and mica, and add it to the mixing bowl over 15 seconds.
(3) Add the polymer slurry to the mixing bowl.
Mix for a total of six minutes, stopping at the end of one and three minutes to rid the sides of the bowl and the paddle of any materials.
(4) Evaluate the joint compound, comparing it to one made by the standard procedure (20 minutes mixing time).
Product Characterization To characterize the products prepared in the examples, the following tests were used.
The stable fluidized suspension of the nonionic thickener comprises 15% or more, by total weight, of a nonionic water soluble polymer dispersed in a aqueous solution of an inorganic salt preferably having a multivalent anion, wherein the weight ratio of the inorganic salt to the water is at least 0.15. Its composition and preparation are described in U.S. Patents 4,883,536 and 4,883,537.
For the thickener, useful water soluble polymers are nonionic and contain hydrophilic substituents such as hydroxyl. Illustrative are hydroxyethylcellulose, hydrophobically modified hydroxyethylcellulose, hydroxypropylcellulose, methyl hydroxypropylcellulose, and hydroxyethyl hydroxypropylcellulose. U.S. Patents 4,338,277, 4,243,802 and 4,826,970 describe some suitable hydrophobically modified cellulosics~.
The concentration of water soluble polymer in the aqueous suspension added as the thickener will be 15% or more. Preferably, the concentration will be in the range of 17 to 50%, and more preferably in the range of 20 to 35%.
Any inorganic salt which may be dissolved in water to a sufficiently high concentration that it will render the water-soluble polymer insoluble with minimal swelling, can be used in this invention. Suitable inorganic salts are diammonium sulfate (also known as ammonium sulfate), diammonium phosphate, ammonium polyphosphate, potassium carbonate, epsom salts (magnesium sulfate hydrate), sodium formate and mixtures thereof.
The weight ratio of inorganic salt to the water in the suspension is at least 0.15 and is preferably 0.18 to 0.6. The desired concentration of salt in water varies with the polymer to be suspended. For hydroxyethylcellulose, a salt to water ratio of 0.18 to 0.25 is preferred.
A number of other additives have been found to provide beneficial properties to the fluidized suspension. Preferred additives are stabilizers, such as hydrophilic fumed silica, and clays such as attapulgite clay. They increase the time over which the suspension will remain stable. Also useful for stabilization, in certain circumstances, are carboxymethylcellulose (CMC), xanthan gum and other water-soluble polymers. For instance, the most preferred stabilizers for hydroxyethyl cellulose suspensions are sodium carboxymethyl cellulose and xanthan gum. Stabilizers are generally used in amounts up to about 2%, and are preferably used in an amount of 0.2% to 1%, by weight of total suspension.
Other additives which can be used include pigments, dispersants, surfactants, glycols and thickening agents.
These are generally used in amounts up to 10%. preferably 0.5% to 2%, by weight of the total suspension.
The fluidized suspensions can be prepared by dissolving the inorganic salt in water to form an aqueous salt solution and, then, dispersing with agitation the water-soluble polymer therein. In the case where other additives are employed, these are typically added to the water before the salt. The slurry may comprise a blend of one or more of hydroxyethylcellulose (HEC), methylhydroxypropylcellulose (MHPC) and hydrophobically 20391 2~
modified hydroxyethylcellulose (HMHEC) or other similar modified cellulosic polymers.
Joint Compound Most commercial joint compound formulations contain limestone, clay, mica, resinous binder, thickener, lubricant and stabilizer in varying amounts. In some cases, other additives are included to give the composition sufficient body for application to a vertical wall without sagging or melt down. Materials useful for this purpose include, e.g., cellulose fibers in various forms, treated clays, and porous stone flour. When structure additives of this type are added, they normally replace a portion of the inert fillers, i.e., the limestone, mica or clay.
The resinous binder is normally a coalescable vinyl material, such as polyvinyl acetate) which upon drying or curing of the cement forms a thin matrix to hold the clay, limestone, etc. When a fully formulated mix is being prepared, the binder is usually added as an aqueous latex. In the case of dry mixes it is added as spray-dried latex particles. Other materials useful as the binder include, e.g., starch, casein, polyacrylamide, copolymers of acrylamide and acrylic acid.
In addition to the principal ingredients mentioned above, a typical joint compound will frequently also contain a dispersant, a defoamer, and a preservative.
Typically, joint compounds are prepared by combining all of the wet ingredients (and K2C03, if used) and mixing for one minute to homogenize. A blend of all the solids is then added to the mixing bowl, with continuing mixing. The entire mass is blended for a total of about 20 minutes. This procedure may be modified by different manufacturers.
Mixing time cannot simply be shortened in order to increase production. For example, with only 10 minutes mixing, a slightly pasty mixture results. and adhesion suffers. However, the use of a fluidized suspension of the water soluble thickener, as described in this invention, results in easy dispersion throughout the mixture, and faster hydration of the thickener.
Consequently, the mixing time is shortened to about 5 minutes and the production rate is 2 to 3 times that of the usual output.
r The following general procedure was employed to mix the ingredients:
(1) Add all of the liquid ingredients (and K2C03) to the mixing bowl and mix for one minute to obtain a uniform dispersion.
(2) Dry blend the limestone, clay and mica, and add it to the mixing bowl over 15 seconds.
(3) Add the polymer slurry to the mixing bowl.
Mix for a total of six minutes, stopping at the end of one and three minutes to rid the sides of the bowl and the paddle of any materials.
(4) Evaluate the joint compound, comparing it to one made by the standard procedure (20 minutes mixing time).
Product Characterization To characterize the products prepared in the examples, the following tests were used.
Viscosity: Measured in Brabender units (B. U.) determined by ASTM C 474-67.
Cracking: Panels are dried in an essentially vertical position with a current of air from a 14 inch oscillating fan forced across their face from about 30 inches for 45 minutes. the panels are then allowed to dry overnight in the vertical position without the air current. Ratings are assigned subjectively as: none (N), very slight (V.S.), slight (S), moderate (M), or heavy (H).
Sag_ Resistance: Panels of the cement about 4 x 5 x 1/8 inch are cast. Sag is observed at the edges of the panels. Ratings: Excellent: structure of cast panel is retained with sharp edges. Slight:
edges of panel are slightly rounded. Poor: edges of panel smooth and tapered.
Adhesion: By ASTM test C 474-67.
The Invention is illustrated in the following Examples. Parts and percentages are by weight, unless otherwise indicated.
Example 1 Fluidized Suspension of Hydro~hobically Modified Hydroxyethyl Cellulose (HMHEC) A fluidized suspension of HMHEC available from Aqualon Company, Wilmington, DE as AQA D-3082, was prepared as described in U.S. Patent 4,883,537 using the following ingredients.
22124-I_776 _g_ Ingredients Weight WatE~r 63.79 Diarnmonium Sulfate (available from Agway, Inc., Syracuse, New York) 16.0 HMHEC (available from Aqualon Company) 20.0 Xani=han Gum 0.20 Pro:~el* GXL Stabilizer 0.01 The hydrophobic modifier in AQA D-3082 was 3-n-butoxy-2-hydroxypropyl at a molar substitution level of 0.10. It had a hydroxyethyl molar substitution of 3.2. Brookfield viscosity was 500 mPas.
Joint Compound Using the general procedure described previously, a joint compound was prepared from the following formulation.
Joint Compound Formulation - Ing!redients Weight Limestone (Georgia White No. 9) 60.22 A~ttapulgite (Gel B) Clay 1.85 Latex (Ucar*131) Binder 2.25 Mica (P80K)*(available from Unimin Corp., Spruce Pine, North Carolina) 2.75 Propylene Glycol(available from East Falls Corp., Frazer, Pennsylvania) 0.40 Biocides 0.05 Tlhickener 0.48 Water 32.0 * Trade -mark 239 ~ 24 The amount of thickener listed corresponds to the amount of polymer present in the fluidized suspension.
The amount of water in the formulation was then decreased to compensate for the water added with the suspension. Likewise, the limestone was decreased to compensate for the salt (DAS) added with the suspension. The joint compound was prepared by the method described above in the section titled "Mixing Procedure".
The joint compound prepared in this manner had very good properties, as demonstrated by the following:
Appearance: Creamy Viscosity: 500 B.U.
Adhesion: Excellent Sag Resistance: Excellent Cracking: Very Slight Example 2 The joint compound formulation of Example 1 was prepared with dry HMHEC, instead of the fluidized suspension of HMHEC; after mixing for 6 minutes by the general procedures described previously, the product was grainy in appearance and gave poor adhesion, indicative of incomplete dissolution of the polymer. It contained many partially hydrated water-soluble polymer gel particles, which prevented troweling to a smooth finish.
Example 3 Using the procedures described in Example 1, a fluidized suspension of a mixture of methyl hydroxypropylcellulose and hydroxyethylcellulose (Natrosol~ 250 HXR from Aqualon Company) was prepared.
-l~- 2 0 3 9 1 2 4 A joint compound was prepared utilizing this fluidized suspension in the joint compound formulation given for Example 1, but with 0.56% thickener. The joint compound had very good properties, as demonstrated by the following:
Appearance: Creamy Viscosity: 570 B.U.
Adhesion: Excellent Sag Resistance: Excellent Cracking: Very Slight Example 4 Using the procedures described for Example 1, a fluidized suspension of mixture of methyl hydroxypropylcellulose and hydroxyethylcellulose polymer (Natrosol~ 250HHXR) was prepared. A joint compound was prepared utilizing this fluidized suspension in the joint compound formulation given for Example 1, but with 0.40%
polymer and 2.0% Attapulgite. The joint compound had very good properties, as demonstrated by the following:
Appearance: Creamy Viscosity: 540 B.U.
Adhesion: Excellent Sag Resistance: Excellent Cracking: Slight These examples demonstrate a new aqueous joint compound formulation and a process for its preparation and use, utilizing a particulate water soluble polymer thickener in an aqueous suspension in a solution of an ammonium salt, which provides much more rapid thickening and equilibration of the joint compound formulation than prior art thickeners employed in their dry form. In addition, less cracking and shrinkage of the joint compound was evident.
Example 5 A fluidized suspension of HMHEC was prepared utilizing the following ingredients:
Ingredients Weight Water 63.7 Diammonium phosphate 16.0 HMHEC (available from Aqualon Company) 20.0 Xanthan gum 0.2 Proxel GXL 0.1 The so-formed suspension was observed to be fluid, pourable and stable to particle settling with time.
Joint Compound A joint compound was prepared utilizing this fluid suspension as a thickening agent with a 5 minute thickening time as practiced in Example 1. The joint compound prepared in this manner had the following properties:
Appearance: Creamy Viscosity: 550 B.U.
Adhesion: Excellent Sag Resistance: Excellent Cracking: Very Slight The above example showed that ammonium phosphate was a suitable salt for joint compounds of the present invention.
Example 6 A fluidized suspension of HMHEC was prepared according to the method of example 1 with the following compositions:
__T.._~.___._ _ __.__.._ ._.
Ingredients Weight Water 4g,~
Sodium formate 20.0 HMHEC (available from Aqualon Company) 30.0 Xanthan gum 0.2 Proxel GXL 0.1 The so-formed suspension was observed to be fluid and pourable and to show minimal solids settling upon standing with time.
Joint Compound A joint compound was prepared according to the method of Example 1 employing the above polymer suspension as the thickening agent. The joint compound prepared in this manner had the following properties:
Appearance: Creamy Viscosity: 480 B.U.
Adhesion: Excellent Sag Resistance: Excellent Cracking: Slight The above example showed that sodium formate was an effective salt for preparing joint compounds of the present invention.
Example 7 A fluidized suspension was prepared according to the method of Example 1 which employed the the following composition:
Ingredients Weight Water 63.8 Culminalm 20,000 PFR (Aqualon) 20.0 Epsom Salt (magnesium sulfate hydrate) 16.0 Xanthan gum (available from Ashland Chemical Corp.) 0.2 The so-formed suspension was observed to be fluid, pourable and stable.
Joint Compound A joint compound was prepared according to the method of example 1 that employed the above fluid suspension as the thickening agent. The joint compound prepared in this manner had the following properties:
Appearance: Smooth Viscosity: 470 B.U.
Adhesion: Excellent Sag Resistance: Excellent Cracking: Slight This example demonstrated that epsom salts could be employed as the salt ingredient in the present invention.
r. ._..__..
Cracking: Panels are dried in an essentially vertical position with a current of air from a 14 inch oscillating fan forced across their face from about 30 inches for 45 minutes. the panels are then allowed to dry overnight in the vertical position without the air current. Ratings are assigned subjectively as: none (N), very slight (V.S.), slight (S), moderate (M), or heavy (H).
Sag_ Resistance: Panels of the cement about 4 x 5 x 1/8 inch are cast. Sag is observed at the edges of the panels. Ratings: Excellent: structure of cast panel is retained with sharp edges. Slight:
edges of panel are slightly rounded. Poor: edges of panel smooth and tapered.
Adhesion: By ASTM test C 474-67.
The Invention is illustrated in the following Examples. Parts and percentages are by weight, unless otherwise indicated.
Example 1 Fluidized Suspension of Hydro~hobically Modified Hydroxyethyl Cellulose (HMHEC) A fluidized suspension of HMHEC available from Aqualon Company, Wilmington, DE as AQA D-3082, was prepared as described in U.S. Patent 4,883,537 using the following ingredients.
22124-I_776 _g_ Ingredients Weight WatE~r 63.79 Diarnmonium Sulfate (available from Agway, Inc., Syracuse, New York) 16.0 HMHEC (available from Aqualon Company) 20.0 Xani=han Gum 0.20 Pro:~el* GXL Stabilizer 0.01 The hydrophobic modifier in AQA D-3082 was 3-n-butoxy-2-hydroxypropyl at a molar substitution level of 0.10. It had a hydroxyethyl molar substitution of 3.2. Brookfield viscosity was 500 mPas.
Joint Compound Using the general procedure described previously, a joint compound was prepared from the following formulation.
Joint Compound Formulation - Ing!redients Weight Limestone (Georgia White No. 9) 60.22 A~ttapulgite (Gel B) Clay 1.85 Latex (Ucar*131) Binder 2.25 Mica (P80K)*(available from Unimin Corp., Spruce Pine, North Carolina) 2.75 Propylene Glycol(available from East Falls Corp., Frazer, Pennsylvania) 0.40 Biocides 0.05 Tlhickener 0.48 Water 32.0 * Trade -mark 239 ~ 24 The amount of thickener listed corresponds to the amount of polymer present in the fluidized suspension.
The amount of water in the formulation was then decreased to compensate for the water added with the suspension. Likewise, the limestone was decreased to compensate for the salt (DAS) added with the suspension. The joint compound was prepared by the method described above in the section titled "Mixing Procedure".
The joint compound prepared in this manner had very good properties, as demonstrated by the following:
Appearance: Creamy Viscosity: 500 B.U.
Adhesion: Excellent Sag Resistance: Excellent Cracking: Very Slight Example 2 The joint compound formulation of Example 1 was prepared with dry HMHEC, instead of the fluidized suspension of HMHEC; after mixing for 6 minutes by the general procedures described previously, the product was grainy in appearance and gave poor adhesion, indicative of incomplete dissolution of the polymer. It contained many partially hydrated water-soluble polymer gel particles, which prevented troweling to a smooth finish.
Example 3 Using the procedures described in Example 1, a fluidized suspension of a mixture of methyl hydroxypropylcellulose and hydroxyethylcellulose (Natrosol~ 250 HXR from Aqualon Company) was prepared.
-l~- 2 0 3 9 1 2 4 A joint compound was prepared utilizing this fluidized suspension in the joint compound formulation given for Example 1, but with 0.56% thickener. The joint compound had very good properties, as demonstrated by the following:
Appearance: Creamy Viscosity: 570 B.U.
Adhesion: Excellent Sag Resistance: Excellent Cracking: Very Slight Example 4 Using the procedures described for Example 1, a fluidized suspension of mixture of methyl hydroxypropylcellulose and hydroxyethylcellulose polymer (Natrosol~ 250HHXR) was prepared. A joint compound was prepared utilizing this fluidized suspension in the joint compound formulation given for Example 1, but with 0.40%
polymer and 2.0% Attapulgite. The joint compound had very good properties, as demonstrated by the following:
Appearance: Creamy Viscosity: 540 B.U.
Adhesion: Excellent Sag Resistance: Excellent Cracking: Slight These examples demonstrate a new aqueous joint compound formulation and a process for its preparation and use, utilizing a particulate water soluble polymer thickener in an aqueous suspension in a solution of an ammonium salt, which provides much more rapid thickening and equilibration of the joint compound formulation than prior art thickeners employed in their dry form. In addition, less cracking and shrinkage of the joint compound was evident.
Example 5 A fluidized suspension of HMHEC was prepared utilizing the following ingredients:
Ingredients Weight Water 63.7 Diammonium phosphate 16.0 HMHEC (available from Aqualon Company) 20.0 Xanthan gum 0.2 Proxel GXL 0.1 The so-formed suspension was observed to be fluid, pourable and stable to particle settling with time.
Joint Compound A joint compound was prepared utilizing this fluid suspension as a thickening agent with a 5 minute thickening time as practiced in Example 1. The joint compound prepared in this manner had the following properties:
Appearance: Creamy Viscosity: 550 B.U.
Adhesion: Excellent Sag Resistance: Excellent Cracking: Very Slight The above example showed that ammonium phosphate was a suitable salt for joint compounds of the present invention.
Example 6 A fluidized suspension of HMHEC was prepared according to the method of example 1 with the following compositions:
__T.._~.___._ _ __.__.._ ._.
Ingredients Weight Water 4g,~
Sodium formate 20.0 HMHEC (available from Aqualon Company) 30.0 Xanthan gum 0.2 Proxel GXL 0.1 The so-formed suspension was observed to be fluid and pourable and to show minimal solids settling upon standing with time.
Joint Compound A joint compound was prepared according to the method of Example 1 employing the above polymer suspension as the thickening agent. The joint compound prepared in this manner had the following properties:
Appearance: Creamy Viscosity: 480 B.U.
Adhesion: Excellent Sag Resistance: Excellent Cracking: Slight The above example showed that sodium formate was an effective salt for preparing joint compounds of the present invention.
Example 7 A fluidized suspension was prepared according to the method of Example 1 which employed the the following composition:
Ingredients Weight Water 63.8 Culminalm 20,000 PFR (Aqualon) 20.0 Epsom Salt (magnesium sulfate hydrate) 16.0 Xanthan gum (available from Ashland Chemical Corp.) 0.2 The so-formed suspension was observed to be fluid, pourable and stable.
Joint Compound A joint compound was prepared according to the method of example 1 that employed the above fluid suspension as the thickening agent. The joint compound prepared in this manner had the following properties:
Appearance: Smooth Viscosity: 470 B.U.
Adhesion: Excellent Sag Resistance: Excellent Cracking: Slight This example demonstrated that epsom salts could be employed as the salt ingredient in the present invention.
r. ._..__..
Claims (10)
1. An aqueous joint compound formulation comprising calcium carbonate, clay, binder, mica, lubricant and a thickener, characterized in that the thickener is an aqueous suspension of a nonionic cellulose ether in an inorganic salt, wherein the suspension consists of 15% or more by weight of the cellulose ether based on the total weight of the suspension and the weight ratio of the inorganic salt to water in the suspension is at least 0.15.
2. The formulation of claim 1, wherein the nonionic cellulose ether is hydrophobically modified hydroxyethylcellulose.
3. The formulation of claim 2, wherein the hydrophobically modified hydroxyethylcellulose is hydrophobically modified by a 3-n-butoxy-2-hydroxypropyl group.
4. The formulation of claim 1, wherein the nonionic cellulose ether is methylhydroxypropylcellulose.
5. The formulation of claim 1, wherein the suspension may contain one or more of hydroxyethylcellulose, methylhydroxypropylcellulose or hydrophobically modified hydroxyethylcellulose as blends.
6. The formulation of any one of claims 1 to 5, wherein the .inorganic salt is selected from the group consisting of diammonium sulfate, diammonium phosphate, potassium carbonate, magnesium sulfate and sodium formate.
7. A process for preparing an aqueous joint compound form,alation comprising the steps:
(1) preparing an aqueous suspension of a cellulose ether in an inorganic salt;
(2) preparing a mixture of joint compound ingredients including a latex binder; and (3) adding the suspension to the mixture to prepare a storage stable joint compound formulation.
(1) preparing an aqueous suspension of a cellulose ether in an inorganic salt;
(2) preparing a mixture of joint compound ingredients including a latex binder; and (3) adding the suspension to the mixture to prepare a storage stable joint compound formulation.
8. The process of claim 7, wherein the latex binder is added after the suspension and other joint compound ingredients have been mixed.
9. The process of claim 7 or 8, wherein the inorganic salt is selected from the group consisting of diammonium sulfate, diammonium polyphosphate, potassium carbonate, magnesium sulfate and sodium formate.
10. The process of any one of claims 7 to 9, wherein the cellulose ether is hydrophobically modified hydroxyethylcellulose.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US50835590A | 1990-04-12 | 1990-04-12 | |
| US508,355 | 1990-04-12 |
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| Publication Number | Publication Date |
|---|---|
| CA2039124A1 CA2039124A1 (en) | 1991-10-13 |
| CA2039124C true CA2039124C (en) | 2001-12-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2039124 Expired - Fee Related CA2039124C (en) | 1990-04-12 | 1991-03-26 | High productivity joint compound |
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|---|---|
| CA (1) | CA2039124C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6712897B2 (en) * | 2001-05-21 | 2004-03-30 | National Gypsum Properties, Llc. | Pre-blend composition, and method of making joint compound using same |
-
1991
- 1991-03-26 CA CA 2039124 patent/CA2039124C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2039124A1 (en) | 1991-10-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |