Document 6wba8rx0R2XBJoQ9e9m56ZE9o

FILE NAME ICI ICI DATE 1974 Sept 10 DOC ICI048 DOCUMENT DESCRIPTION Patent United States Patent Office 3,835,074 Patented Sept. 10 1974 1 2 covering taped joints Most commercial formulations are 3,835,074 within the following concentration ranges JOINT CEMENT COMPOSITIONS Armand J. Desmarais New Castle Del assignor to Hercules Incorporated Wilmington Del No Drawing Filed Apr. 26 1973 Ser No. 354,713 Int Cl C08f 37/16 45/18 Calcium carbonate 190 to 350 parts by weight Mica 30 to 90 parts by weight 5 Clay 0 to 100 parts by weight Binder 20 to 44 parts by weight Claims U.S. Cl 260-17 3 Claims If the product is to be sold as a ready formulation water in the amount of about 30 to 40 based on the 10 total weight of the dry ingredients is added and thorough- ABSTRACT OF THE DISCLOSURE Joint cements suitable for use with plaster wallboard ly mixed All compositions within the limits just described are suitable for manual application by troweling used When are disclosed wherein the asbestos customarily to impart water binding properties and pseudoplasticity is they are to be applied mechanically additional water is added at the job site just prior to use in replaced by a insoluble fibrous hydroxyethyl cellu- 15 The cellulose derivatives which can be employed in lose this invention are insoluble fibrous materials as distinguished from the conventional fibrous hydroxyethyl cellulose of commerce which is soluble Water in- This invention relates to compositions useful as joint solubility is assured either by maintaining the M.S. at a sealing materials for the installation of wallboard panel- 20 low level i.e. below about 1.2 or by the use of hydroxy- ing in e.g. residential and office building construction ethylation techniques which produce a nonuniformly sub- More specifically it refers to such compositions wherein stituted product The water insolubility is a critical factor a cellulose derivative is employed to impart desirable in the performance of the hydroxyethyl cellulose as an properties thereto asbestos substitute A soluble material such as con- Since the end of the second World War the use of Ventional hydroxyethyl cellulose at economical concen- wallboard has all but displaced plaster in erection of 25 tration levels would not impart the consistency needed interior walls in the construction of buildings Wallboard for the pseudoplasticity normally obtained with asbestos is generally installed in 4 x 8 foot panels which are nailed The above paragraph must not be taken to mean that and glued to the studding of the wall and fitted together no soluble hydroxyethyl cellulose is to be employed until the entire section of wall is covered The joints 30 soluble hydroxyethyl cellulose is frequently included where sections of the board are butted together are cov- as a thickener in limestone based joint cements and can ered with tape and then taped joints and all nails are be so used in the compositions of this invention It is only covered with a joint cement or spackling compound the hydroxyethyl cellulose employed in substitution for which upon hardening can be sanded smooth so that asbestos that need be water insoluble wallpaper it is imperceptible under paint or 35 To duplicate properties of conventional joint cements Joint cements heretofore employed with wallboard have the concentration of the insoluble hydroxyethyl cel- contained a resinous binder limestone clay mica and lulose can be from about an equal quantity to 12 that with asbestos the principal ingredients which are mixed of the asbestos being replaced depending on the M.S. water to form a dope Asbestos is included in these for- of the hydroxyethyl cellulose used If the M.S. of the mulations for several purposes It imparts lubricity work- 40 hydroxyethyl cellulose is in the range of 0.15 to 0.6 the ability water binding and pseudoplasticity to the wet mix concentration employed can be in the range of % to and being fibrous provides reinforcement of the cement % based on the dry weight of the formulation Due to on drying 4 the superior binding capacity of the cellulose de- Recently disclosed evidence that certain types of as- rivative having an M.S. in the range of 0.6 to 1.2 the bestos may have carcinogenic characteristics has prompted 45 concentration of the additive which is effective can be issuance of severely restrictive regulations by OSHA re- about 0.5 to 1.5 based on the total dry weight of the garding its use in construction applications and may even- formulation Thus the concentration of the additive can tually lead to its being banned altogether For this rea- be about 0.5 to % based on the total dry weight of the son an effort is now under way to find substitutes to formulation Employing conventional joint cement recipes place asbestos in most of its present applications re- 50 the additional weight of asbestos not replaced by cellulose In recent work by the instant inventor it has been derivative is replaced by additional limestone or mica found that cellulose derivatives can be used so that the total weight of product remains the same ment for asbestos in joint cement More as a replace- As suggested previously it is important that the hy- invention relates to specifically this droxyethyl cellulose be in fibrous form For best results joint cement compositions based on 55 the fiber length should be between about 0.03 and 0.007 a resinous binder mica clay and limestone as major dry inch If the fiber length becomes too components along with a fibrous insoluble hy- cement composition is curdy and great the resulting droxyethyl cellulose having an M.S. between about 0.15 not satisfactory On the other hand if the fibrous form and 1.4 Joint cements are maketed in is lacking the water- fully formulated ready form i.e. already containing binding capacity of the hydroxyethyl cellulose is not suf- water and as 60 ficient to reproduce the properties of conventional joint a dry powder to which water is added at the time of use cements The invention includes such dry powders as well as the fully formulated cements Joint cement In some cases the hydroxethyl cellulose alone can give this invention compositions of the composition sufficient body for application to a vertical are substantially identical in performance wall without sagging or down In other to those which are presently available commercially and 65 structure additive can be added to increase cases a based on current price levels they are competitive in the level the body to price necessary Materials useful as structure addi- In commercial practice the concentrations tives for this purpose include e.g. cellulose fibers in cipal ingredients can and do of the prin- various forms treated clays and porous stone flour When vary widely between suppliers and depending on the intended structure additives of this type are added they normally it is for end use i.e. whether replace a portion of one of the inert fillers i.e. limestone patching holes covering nail pops or for initially mica or clay 3,835,074 3 4 The resinous binder is normally a coalescable vinyl The latex binder was a 55 by weight aqueous disper- material preferably vinyl acetate which upon dry- sion of vinyl acetate containing a plasticizer The ing or curing of the cement forms a thin matrix to hold the clay limestone etc. When a fully formulated mix is dispersant was a polymerized sodium salt of a sulfonic acid sold under the trade name Daxad 30. The defoamer being prepared the binder is usually added as aqueous was a silica dispersion in a hydrocarbon solvent The latex In the case of dry mixes it is added as spray dried preservative was a mercurial fungicide compound latex particles Other materials useful as the binder include e.g. starch casein polyacrylamide and copolymers Examples 1 to 11 of acrylamide and acrylic acid The procedure and the formulation set forth for the In addition to the principal ingredients mentioned 10 control example were repeated using the following insol- above a typical joint cement will frequently also contain uble hydroxyethyl cellulose modifications in place of as- a small amount of a dispersant a defoamer a preserva- bestos The fine fluffy fibers are all within the 0.03 to tive and a thickener In the following examples the invention is illustrated 0.007 in range they passed through a mesh screen and were held on mesh Parts and percentages are by weight unless otherwise indi- 15 cated The following general procedure was employed to Example 1 mix the ingredients Asbestos was replaced with 48 grams of hydroxyethyl In preparing a ready mix formulation the water and binder latex were charged to a mixing apparatus and cellulose having M.S. 0.32 in the form of fine fluffy fibers having water retention power of 10 g./g mixed for a short time before the dispersant defoamer 20 and preservative were added The dry ingredients lime- Example 2 stone mica clay hydroxyethyl cellulose and structure Asbestos was repleced with 48 grams of hydroxyethyl additives if used were dry blended and added incre- cellulose having M.S. of 0.4 in the form of fine fluffy mentally to the stirred liquid After the last of the dry fibers having water retention power of 10 g./g ingredients was added the mix was stirred for about an- 25 other 10 minutes at low speed with occasional stopping Example 3 to scrape down the sides of the bowl To characterize the products prepared in the examples Asbestos was replaced with 24 parts of limestone and the following tests were used 24 parts of hydroxyethyl cellulose having M.S. of 0.4 in the form of fine fluffy fibers having water retention power VISCOSITY 30 of 10 g./g Measured in Brabender units B.U. determined by ASTM 474-67 Sections 2 and 3 Example 4 Asbestos was replaced with 44 parts of limestone and 4 parts of hydroxyethyl cellulose having M.S. of 0.82 in CRACKING 35 the form of fine fluffy fibers having water retention power Panels were dried in an essentially vertical position with a current of air from a 14 inch oscillation fan forced of 19 g./g Example 5 across their face from about 30 inches for 45 minutes Asbestos was replaced with 40 parts of limestone and The panels were then allowed to dry overnight in the 40 8 parts of hydroxyethyl cellulose having M.S. of 0.82 in vertical position without the air current Ratings were the form of fine fluffy fibers having water retention power assigned subjectively as none N very slight V.S. of 19 g./g slight S moderate M or heavy H Example 6 ' DOWN Asbestos was replaced with 40 parts of limestone and 45 8 parts of hydroxyethyl cellulose having M.S of 0.78 in Panels of the cement about " x " x 18 were cast the form of fine fluffy fibers having water retention power down was observed as sag at the edges of the panels of 18 g./g Excellent structure of cast panel is retained with sharp edges Slight Edges of panel are slightly Example 7 rounded Moderate Edges are slightly more rounded 50 Asbestos was replaced with 42 parts of limestone and Poor Edges of panel are smooth and tapered 6 parts of hydroxyethyl cellulose having M.S. of 0.78 in ADHESION the form of fine fluffy fibers having water retention power of 18 g./g By ASTM test C 474-67 Example 8 55 CONTROL EXAMPLE Asbestos was replaced with 42.7 parts of limestone and 5.3 of hydroxyethyl cellulose having 0.88 M.S. in the This control example is intended to illustrate the properties of a conventional joint cement employing asbestos form of fine fluffy fibers having water retention power of 20 g./g as a water retention aid The following standard joint 60 Example 9 cement formulation was prepared using the procedures set forth above Asbestos replaced by 40 parts of limestone and 8 parts of hydroxyethyl cellulose having an M.S. of 0.81 in the Limestone 98 CaCO3 Parts ~ 250 form of fine fluffy fibers having water retention power Mica 325 mesh of 19 g./g 76 65 ~- Clay 76 Example 10 Latex binder ..--.____ Dispersant ~-_.-.----..-----_- Preservative Water 61 Asbestos replaced by 48 parts of hydroxyethyl cellulose 4 having an M.S. of 0.82 in the form of fine fluffy fibers --- ._ 0.2 having water retention power of 19 g./g ----- 280 70 Defoamer cellulose Hydroxyethyl cellulose 1 Asbestos 5-1000... 4.6 Example 11 2 Asbestos replaced by 48 parts of hydroxyethyl cellulose 48 having an M.S. of 0.15 having water retention power of 1 soluble grade M.S. 2,5 2000 ccpps s viscosityviscosity in 1 % 5 g./g prepared by fibrillation of a pressed sheet into aqueous solution 75 fibers greater than 0.033 in 3,835,074 5 Example The properties of the above Control and Ex- amples 1 through 11 are recorded in the following table 6 consistency exhibited slight cracking and very slight melt- down Example Control Viscosity 560 Melt- lbs./gal Density Cracking down Aphesion Appearance 12.42 Slight N S M Satisfactory . Smooth do Do. 12.7 None 12.172. .7 d .o .... S ..do do Smooth Smooth creamy Slightly grainy _do_ Smoo- th. _do__ _do__ Smooth 12.8 _do_ 12.8 _do 12.8 S do Do. _do_ Too V.S. Do. viscousSatisfactboertyestedFibrous and curdy Examples 12-17 Example 18 Using the recipe set out above additional additional joint joint cement The following ingredients were dry mixed by tumbling Limestone compositions were prepared in which some of the asbes- 20 tos was replaced with a mixture of low M.S. hydroxyethyl Mica cellulose acicular attapulgite clay and talc and the remainder with additional limestone Binder 25 Hydroxyethyl cellulose 2 Parts o 29 76 76 2.5 Hydroxyethyl 3 Example 12 cellulose 4 1 dried vinyl acetate latex Spray poly 2 M.S. 2.5 2000 cps in % water solution One part of hydroxyethyl cellulose having 0.82 M.S. 0.82 fibers of 0.03 to 0.007 in water retention of g./g g./g 2 parts clay and 4 parts talc Product was slightly grainy 30 but exhibited only slight cracking and excellent melt- The dry blended ingredients were mixed with 280 parts of water the mix was allowed to slake for 20 minutes and down a was then mixed again to a uniform consistency and eval- Example 13 uated as in the previous examples Results were as fol- lows 35 One part hydroxyethyl cellulose having 0.41 M.S. 2 Viscosity 560 parts clay and 9 parts talc Product had smooth creamy Density consistency and exhibited only moderate cracking and Cracking down slight down 40 Adhesion Example 14 Appearance Structure 12.8 N. V.S. Satisfactory Smooth Good One part hydroxyethyl cellulose having 0.53 M.S. 2 What I claim and desire to protect by Letters Patent is parts clay and 9 parts talc Product had smooth creamy 45 1. A joint cement composition consisting essentially of a coalescable vinyl resin binder mica clay and limestone consistency and exhibited no cracking and slight melt- down as its principal dry ingredients and containing about 0.5 to % by weight based on the total weight of the dry Example 15 components of fibrous insoluble hydroxyethyl cel- 50 lulose having a hydroxyethyl M.S. of about 0.6 to 1.2 One part hydroxyethyl cellulose having 0:63 M.S. 2 2. The composition of claim 1 wherein the hydroxy- parts clay and 9 parts talc Product had ethyl cellulose has a hydroxyethyl M.S. of about 0.6 to smooth creamy 1.2 and is present in a concentration of about 0.5 to 1.5 consistency exhibited no cracking and slight down 3. The composition of claim 1 wherein the 55 ethyl cellulose has a hydroxyethyl M.S. of abouthy0d.r1o5xyt-o Example 16 0.6 and is present in a concentration of about 1 to % One part hydroxyethyl cellulose having 0.8 M.S. 2 References Cited parts clay and 9 parts talc Product had smooth creamy slightly more viscous consistency exhibited no cracking 60 and very slight down Example 17 3,382,119 3,411,926 3,044,973 2,816,872 UNITED 5/1968 11/1968 7/1962 12/1957 STATES PATENTS Henkel e eee e ae ae oe Gogek ett -71 Eee Segro . 260-39 Yourtee One 65 THEODORE MORRIS Primary Examiner part hydroxyethyl cellulose having 0.82 M.S. 1.2 parts clay and 5.2 parts talc Product had smooth creamy 106-141 U.S. Cl X.R.