TAPE JOINT COMPOUNDS
Publication Date: 2004-Apr-21
The IP.com Prior Art Database
Larry Hyman: INVENTOR [+1]
The use of poly(ethylene oxide) homopolymers, such as POLYOX(TM) water soluble resins, imparts an unexpected increase in viscosity in tape joint compositions. This increase in viscosity is mostly evident in combination with hydroxyethyl cellulose, such as CELLOSIZE(TM) hydroxyethyl cellulose. This increased thickening effect allows manufacturers of tape joint compositions to use less thickener or more water to arrive at the desired viscosity. Further it leads to an improved hand tool workability and a better spray texture application of the tape joint compositions.
Tape Joint Compounds
Tape joint compounds (TJC) are materials that are trowelled into the joint between two wallboards to make the surface appear to be seamless. The trowelling is accomplished with the use of several different tools; for example, broadknives of various lengths or mechanical box tools of various lengths. In addition, TJC may be hand applied over the entire wall surface or ceiling surface to form a texture; for example, knock down, orange peel, etc. Also, additional water may be added to TJC and then it may be sprayed applied over the entire wall surface or ceiling surface to form a texture.
TJC are comprised of limestone, clay, mica, thickener, preservative and water. In addition, many other components are commonly used to obtain specific performance; e.g., starch, derivitized starch, talc, defoamer, humectant or perlite. The thickener may be a hydroxypropylmethyl cellulose, hydroxyethyl cellulose, hydroxyethylmethyl cellulose, hydrophobically modified hydroxyethyl cellulose, ethylhydroxyethyl cellulose, etc.
It has been found that the use of poly(ethylene oxide) homopolymers, in particular the use of POLYOXTM water soluble resins will impart an increase in viscosity in TJC that is unexpected. That is, although POLYOXTM water soluble resins do thicken water, the achieved degree of thickening is greater than what would normally be expected. It has been observed that this increase in viscosity is mostly evident in combination with hydroxyethyl cellulose, in particular with CELLOSIZETM hydroxyethyl cellulose. This effect is observed in regular weight and light weight TJC formulations.
POLYOX water soluble resins and CELLOSIZE hydroxyethyl cellulose are commercially available from Union Carbide Corporation, a subsidiary of The Dow Chemical Company,
POLYOX water soluble resins offer the opportunity to manufacturers of TJC to use less thickener or more water in TJC formulations to arrive at an equivalent viscosity as a TJC with no POLYOX water soluble resins in the formulation. Further, TJC formulated with a POLYOX water soluble resin impart an excellent hand tool workability to the applicator as compared to those without a POLYOX water soluble resin. In addition, the higher viscosity allows for better spray texture application of a TJC.
TJC viscosity are determined by allowing the TJC to age at least three days and using a Brabender viscometer, pin sensor, 250 cmg spring, and 75 RPM rotational speed.
Regular weight TJC were formulated using the recipe below.
Component Weight Parts