Document q32r65bMxyR610qXQox5w2EKx

FILE NAME: Hercules Chemical (HERC) DATE: 1974 Sept 10 DOC#: HERC019 DOCUMENT DESCRIPTION: Patent - Joint Cement Compositions l i t u r rrturi* > W * X H U U U mf I d 1 I I U nited States P atent Office Patented Sep3t,8130,51,097744 covering taped joints. Most commercial formulations a n 3J3S.974 JOINT CEMENT COMPOSITIONS A n m u d J. Desm arab, New Casti, D e l, asshmor to Hercules Inccxpontcd, W lhdasten. Del. N o Drowiag. le d Apr. 26, 1971, Ser. No. 164,719 l o t C LC O tf 37/16,45/18 V S C t 169--17 9 C hine ABSTRACT OF THE WSCtOSURF. w ithk the following concentration ranges: Calcium carbonate. 1P0 to 3$0 parts by weight Mica, 30 to 90 parts by weight. 6 Clay, 0 to 100 parts by weight. Binder, 20 to 44 parts by w eight - If the product is to be sold os n ready-mix formulation, water in the amount of about 30 to 409b, based on the j 0 total weight of the dry ingredients, is added and thorough* ly mixed. AD compositions within (be limits just described Joint cements suitable for use with plaster wallboard ere suitable for manual application by troweling. When aro disclosed wherein the asbestos customarily used to they a n to be applied meehtnietny, additional water is impart water bindin properties and pscudoplasticity is added at the job rite just prior to use. replaced by a water-insoluble, fibrous hydroxyethyi cellu- id The cellulose derivatives which can be employed in low. this invention ere water-insoluble, fibrous material as distinguished from tho conventional fibrous hydroxyethyi cellulose of commerce which is water-soluble. W ater in* This invention relates to compositions useful us joint s_o_l_u_b_i_lit,y .is. . _a_ss_u_r_e_d__e_it_h_er__b_y__m_a_i_n_ta_i_n_i_ng _t_h_e_M__._$.__at .a sealing materials for the installation of wallboard panel- sn low level, is ., below about 1.2, or by the use of hydroxy- iidnfgf 1Hn_, #e_gfif.,_ rBeMsiudtennnfttifaill aMnldft oaIfRfi^che bk tuiiillrdiitnnga cntovniaestlvreuwcftiiAoanl More specifically, it refers to such compositions wherein a cellulose derivative is employed to impart desirable prop. erties thereto. neitlhtuyllaattiiMoni techniques which ipBrM od.tun_c_e_ _ a__n__o__n__u__n_*ifo- rmVly _suLb stituted product The water insolubility Is a critical factor in the performance of the hydroxyethyi cellulose as an asbestos substitute, a water-soluble materiel such us con sume the end of the second World War, the use e i o j ventloual hydroxyethyi cellulose, at economical concen- waUbosid has all but displaced plaster in erection o f uuenor warn m use construction of building*. Wallboard tratioa levels, would not impart the consistency needed for the pseudoplasticity normally obtained with asbestos, w generally installed in 4 x 9 foot panels which ans nailed The above paragraph must not be taken to mean that .'w* to the studding of the wall and fitted together do water-soluble hydroxyethyi cellulose is to be employed, uahl the entire section of wall is covered. The joints ao Water-soluble hydroxyethyi cellulose is frequently included Where lections o f the board arc butted together are cov *e9tsm uat tfW haiscetkamemnimemr lta. limestone kbaassAedJ jfo. inst c--e-- men-ts a^ndJi c.aa^ n ered with a p e and then taped joints and all nails arc be so used in the compositions of this invention. Jt is only c o w e d with a joint ceosent o r "speckling" compound the hydroxyethyi cellulose employed in substitution for which, upon hardening, can be sanded smooth so that asbestos that need be water insoluble. it is imperceptible under paint o r wallpaper. Sg T o duplicate properties o f conventional joint cements, Joint cements heretofore employed with wallboard have the concentration of the water-insoluble hydroxyethyi Cel contained a resinous binder, limestone, day, mica and aabeatoa the principal Ingredients which am mixed with lulose can be from about an equal quantity to Ms that of the asbestos being replaced, depending on the M S. water to form a dope. Asbestos is included m these for of the hydroxyethyi cdlulose used. I f the M-S. o f the mutations for several purposes. U imparts lubricity, work- so hydroxyethyi cellulose is in the range o f 0.15 to 0.6, the ability, water binding, and pscudoplasticity to die wet m ix concentration employed can be in the range of 1% to and, being fibrous, provides reinforcement of the cement 9% besed on the dry weight of the formulation- Due to on drying. - the superior water-binding capacity of the cellulose de- Recetfly disclosed evidence that certain types of at- vivativs having an M.S. in the range Of 0.4 to 1.2, the bestos may have carcinogenic characteristics has prompted ** concentration o f the additive which is effective can be issuance of severely restrictive regulations by OSHA re- garding its use in construction indications and may even tually lead to its being banned altogether. For this rea son, sn effort is now under way to find substitutes to re place asbestos in most o f its present applications. In recent work by the instant inventor, it has been found that cdlulose derivatives can be used as a replace ment .f.or asb, estos In jo-i-n-t--c--e-m---e-n--t.--M---o-r-e---sp'e--cif"i--ca"llJy., this 10 o to ,1c*nKm* composition* bawd on a resinous binder, mics, clay, end limestone as major dry ? KWt, ? to J * hated on the tots! dry weight of the formulation. Thus, the concentration of the additive can he about 0.5 to 9% based on the total dry weight o f the formulation. Employing conventional joint cement recipes, go the additional weight o f asbestos, not replaced by cellulose derivative, it replaced by additional limestone or mica so that the total weight o f product remains the same. As suggested previously, It is important that the hy droxyethyl cellulose be in fibrous form. For best results 55 the fiber length should be between about 0.03 and 0.007 inch, i f the Cher length becomes too great, the resulting m ponqnts, along with a fibroin, waier-in$otobfe by- cement competition curdy end not atnfocioiy. On the droxyethyl cellulose having an M.S. between about 0.15 other hand, if toe fibrous form is lacking* the water- ana 14. Joint cements are maketed in fully formulated, binding capacity of the hydroxyethyi cellulose is not sufresdy-to-uie form, to., already containing water, and as DO Sclent to reproduce the properties of conventional joint a * y powder to Which water is added a t the time of use. The invention include such dry powders as well as the cements. In some cases, the hydroxelhyl cellulose alone can give fully formulated cements. Joint cement compositions of the composition sufficient body for application to a vertical this em o tio n are substantially identical in performance well without sagging or melt-down. In N h tr *!>-, a to those which are presently available commercially and. 4 structure additive can he added to increase the body to ba"sed on "curren`t pries levels, they are competitive i`n the neeesaery level. Material useful as structure addi price. tives for this purpose include, t.g,, cellulose fibers in ' In commercial practice the concentrations of the prin various forms, treated Clays, and porous stone Hour. When cipal ingredients can and do vary widely between sap- structure additives of this type are added, they normally pliers and depending on the intended end use, b e , whether 70 replace a portion of one o f the inert fillers, be., limestone, it is for patching holes, covering nail pop, or for initially mica, o r clay. i u x i r rrcun; 8 ,8 8 6 ,0 7 4 4 The resinous hinder is normally a coeleseable vinyl The latex binder was a 5 3 by weight aqueous disper material, preferably poly (vinyl acetate) which upon dry sion of poly (vinyl acetate) containing a plasticizer. The ing or Hiring o f the eamem forms a th'm matrix to hold dispersant was a polymerized sodium ash of a sulfonic the clay, limestone, etc. When a fully iarraulatod mix is acid sold under the trade name Daxad 30. The defoamer being prepared, the binder is usually added us aqueous . wax a silica dispersion in a hydrocarbon solvent. The latex. In the ease of dry mixes il is added as spray dried 0 preservative was a njorcurial fungicide compound. latex particles. Other materials useful as the binder in clude, e.g , starch, casein, polyacrylamide, and copolymers Examples 1 to II of acrylamide and acrylic acid. The procedure and the formulation set forth for die 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 a email amount of a dispersant, a defoamer, a preserva uble hydroxyethyi cellulose modifications in place o f as bestos. The flue, fluffy fibers are alt within the 0.03 to tive and a thickener. In the following examples, the invention ie iUostrated. 0.007 in. range--ie ., (hey passed through a 20-rnesb screen and were held on to-mesh. Tarts and percentages are by weight unless otherwise indi cated. The following general procedure was employed to W Example 1 saw the ingredients. In preparing a ready mix formulation the water and hinder latex were charged to a mixing apparatus and mixed for a short time before the dispersant, defoamer. and preservative were added. The dry ingredients (lime, Asbestos Wes replaced with 48 grants of hydroxyethyi oellnlose having M S. 0.32, in the form of fine, flulfy fibers having water retention power of 10 g./g. SO Example 2 stone, mica, day, bydroxyethyl cellulose, and structure Asbestos was reptcced with 48 grams of bydroxyethyl additives, if used) rare dry Headed and added incre cellulose having M .s. o f 0.4 in the form of fine, flulfy mentally to the stirred liquid. After the last of the dry fibers having water retention power o f 10 g./g. ingredients was added, the mix was Urrad for about an 86 , other 10 minutes at tow speed with occasional stopping Example 3 to scrape down the sides of the bowi. ' ' T o characterize the produets prepared in the examples, the following tests were used. ,, Asbestos was replaced with 24 parts of limesioue and 24 parts o f hydroxyethyi cellulose having MIA. of 0.4 in the form o f fine, fluffy fibers having wuter retention power VISCOSITY 86 of 10g./g. Example 4 Measured fat Brabcnder units (B.U.) determined by ASTM 474-67, Sections 2 and 3. Asbestos was replaced with 44 parts of limestone and 4 parts of hydroxyethyi cellulose having M S. of 0.82 >'n CRACKING 39 the form o f fine, fluffy fibers having water retention power o f 19 g./g, Panels were dried in an essentially vertical position Example 5 with a current o f sir from a 14 inch oscillation fan forced 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 hydroxyethyi cellulose having MA. of 0.82 in vertictl position without the air current. Ratings were the form o f fine, fluffy fibers having water retention power assigned subjectively as: none (N ), very slight (V A .), of 19 g./g. alight (S), moderate (M ), or heavy (H ). Example 6 MELT-DOWN Panels of the cement about 4 " x 5" x W were east Melt-down was observed as sag a t the edges or the panels. Eatings--Excellent: structure of cast panel is retained with sharp edges. Slight: Edges of panel are slightly rounded. Moderate: Edges are lightly more rounded. Poor: Edges o f panel are smooth and tapered. ADHESION By ASTM test C 474-67. CONTROL EXAMPLE This control a m p le is intended to illustrate the prop erties o f a conventional joint cement employing asbestos as a wafer retsntion aid. The following standard joint cement formulation wet prepared using the procedures set forth above. . ' Peris Limestone (9 8 C a C O j) ____________ ____ ____ 250 M k a (325 m e s h ) ------------------------- 7 Cfiay ._____________ 76 Latex binder . . . . . --------------. . . . . . . . . . . . . . . . . 61 Dispersant -------.------------------------------------------ 4 Preservative . . . __________. . . . . . _________ . . . . 0.2 W ater __________. . . . . . . . . . ________ . . . . ____ 280 Defoamer ___________ . . . . __________ . . . ____ 4.6 Hydroxyethyi cellulose 1 -----------------. . . _________ 2 Asbestos (5^-100(hi)------- . . . . ___________ . . . . . __ 48 <Watw-mtoMc grado, U .I. 2.B. MM epe. viscosity le 1 qaeous solution. . Asbestos was replaced with 40 parts o f limestone and ** 8 ports of hydroxyethyi eeUotose having MA of 0.78 in the form of fine, fluffy fibers having w ater retention power o f 18 g./fl. Example 7 SO Asbestos was replaced with 42 parti of limestone and 6 parts of hydroxyethyi cellulose having MA. a t 0.78 in the form o f fine, fluffy libers having water retention power o f 18 g./g. Example 8 69 Asbestos wag replaced with 42.7 parts of limestone and 5.3 of bydroxyethyl cellulose having 0* 8 M.S. m the form o f fine, fluffy fibers having water retention power of 20 g./g. <0 Example 9 Asbestos replaced by 40 parts of limestone and 8 part of hydroxyethyi cellulose having an MA. of 0.81 in the form of fine, fluffy fibers having wafer retention power 86 of 19 g./g. Example 10 Asbestos replaced by 48 parts o f hydroxyethyi celhilost having an MA. of 0.82 in the form o f floe, fluffy fibers having water retention power of 19 g./g. Example 11 Asbestos replaced by 48 parts of hydroxyethyi cellulose having an M.S. of 0.15, having water retention power of J g ./g . prepared by fibrillation o f a pressed sheet into 75 fibers greater than 0,033 in. j i m e r rnuri; I U i l `U 0 0 7 * i r h1'1 3 ,8 3 5 ,0 7 4 5 The properties of the above Control Example and Examples i through 11 are recorded in the following table- 6 consistency, exhibited slight cracking and Vcty ili|h l m rildown. Xuwvls nomMc O e eto l... t= : Viscosity 03p& Crscktag Sown Aphelion Amnsnnei 7__. Examples 12-17 Example 18 Using Or recipe k ; out above, additional joint cement coropositiona were prepared in which some o f the asbes tos was replaced with a mixture of low M E. hydroxyethyl The following ingredients were dry mixed by tumbling: Limestone - _________ Parts 29 cellulose, acieular atlapalgitc d a y and talc and the re d a y 76 mainder with additional limestone. B in d e r* ______________________________________ 34 23 Hydroxyethyl cellulose * ---------------- -------------- . . . . 2.5 Hydroxyolhyl cellulose > . . . . . _____ . . . . . . . . . . . . . 4 Example 12 One part of bydroxyethyl cellulose having O.B M E , ----- -- ------------------------------ ---- . water retention at 19 *./*. 2 parts clay and 4 parts talc. Product was slightly grainy, 80 Tbs dry blended iagreduuus were mixed with 210 parts but exhibited only slight cracking and excellent melt of water, tbe mix was allowed to slabs for 20 minutes and down. was then mixed again to a uniform consistency and eval uated as in the previous examples. Results were as fol Example 13 lows: S3 One part bydroxyethyl cellulose having 0.41 M.S , 2 V iscosity__________________________ 560. Density ---------------------------- ------------ 12.8. parts d a y and 9 parts talc. Product bad smooth, creamy C racking_______________ _________ N. consistency aud exhibited only moderate cracking and Melt-down _______________________ vs. alight melt-down. 6b Adhesion ,,-------- ------ ----- --_______ - Satisfactory. Example 14 A ppearance--------------------------------------Smooth-creamy. S tru c tu re --------------------------------------- Good. One part hydroxyethyl cellulose having 0,53 M E , 2 'W hit I claim and desire to pretest by Letters Patent is: 1. A joint cement composition consisting essentially of parts d a y and 9 parts talc. Product bad smooth creamy 45 a coaiescable vinyl resin binder, odea, d ay, and limestone consistency aud exhibited no Bracking and slight melt, as its principal dry ingredients and containing about OS down. Example 15 lo 9% by weight, based on die total weight o f the dry components, o f fibrous, water-insoluble hydroxyethyl cel lulose having a hydroxyethyl M R. o f about 0.6 to 1.2. 60 1. The composition o f claim 1 wherein the hydroxy, One part hydroxyethyl cellulose having 0.63 M.S., 2 ethyl cellulose has a hydroxyethyl M.S. o f about 0.6 to perte clay and 9 parts talc. Product had smooth, creamy consistency, exhibited no cracking and slight melt-down. 1.2 and is present in s concentration o f about a s to 1,5%. A The composition of claim 1 wherein the bydroxy* ethyl cellulose has a hydroxyethyl MR. o f about 0.15 to Example 16 6* 0.6 and is present fa a concentration o f about 1 to 9%. One p a tt hydroxyethyl cellulose hating OR M .S, 2 parts clay and 9 parts tele. Product bed smooth, creamy slightly more viscous consistency, exhibited no cracking 0 and very slight melt-down. Reference* Cited UNITED STATES PATENTS 3,382,119 3,11,926 3,044,973 i/1968 H e n k el_______________ 2 6 0 -1 7 11/1968 G o g e k _______________ 106 -2 1 4 7/1962 S e g ro _____________ 260--39 R 2,316.872 12/1957 Yourtee.______________ 26 0 -1 5 Example 17 85 THEODORE MORRIS, Primary Examiner One past hydroxyethyl ccUulom having 0.82 M R , 1.2 parts d ay and 5 2 parts talc. Product had smooth, creamy 106-- 141 U S. a . XJK.