CA2071051A1

CA2071051A1 - Gypsum-based materials, process for their preparation and their use

Info

Publication number: CA2071051A1
Application number: CA002071051A
Authority: CA
Inventors: Christian Rasp; Jan Mazanek; Ulrich Von Gizycki
Original assignee: Individual
Current assignee: Bayer AG
Priority date: 1991-06-14
Filing date: 1992-06-11
Publication date: 1992-12-15
Also published as: DE4119665A1; NO922166L; EP0518156A3; NO922166D0; JPH05213645A; EP0518156A2

Abstract

Improved gypsum-based materials, process for their preparation and their use Abstract Materials based on gypsum and organic additives are improved if they contain polyethers and, if desired, polymers. They can be used in a wide range of areas, for example as slabs in the building sector and for improving plasters, mortars, insulating materials and other construction compositions, casts and/or moulds.

Description

2~71~5~

The present invention relates to improved yypsum-based materials containing polyether polyol additive~ and to a process for their preparation. The improved materials are suitable, ~or example, for medical purposes (for example for casts and dental compositions), for the ~uilding sector ~for example as seam-sealing compositions, plaster ~ materials and for ~he production of fiLnished parts), for ; the production of decorative mouldecl articles and for making ceramic moulds.

Anhydrous gypsum is used as water-hardening active inyredient for a wide range of applications, for example as material for plastering, for casts for immobilisation ~; of parts of the body, as construction material in building-interior extension work and as modelling com-positions. ~fter soaking in water, anhydrous gypsum hardens with setting. However, the hardened gypsum also has serious disadvantages. It is, for example, not water-resistant and is so hard and brittle that it often breaks on exposure to mechanical stress There have already been attempts to improve the proper-ties of set gypsumO Thus, German Offenlegungsschrift 3,320,217 states that gypsum can be mixed with aqueous polyurethane and/or polyurea dispersion , if appropriate with the addition of alcohols, without premature coagula~
tion of the dispersion and after sPtting has improved water and breaking resistance. The disadvantage of gypsum Le A 28 354 - 1 -:.
, . . . .
.
-- : , ~ -;:

2~7~51 modified in this manner is its poor reproducibility, .in particular as a result of nonouniform air inclu~ions and the non-uniform flow behaviour.

Propo~als to make gypsum moxe water-re~istant for ap-plications in the building ~ector by soaking in salt solutions, bitumen or plastic emul3ions have not been successful ~see "Blick dur~h die Wirtschaft" from 19.9.1982, No. 175, p. 7).

Matesials based on gypsum and organic additives have now : lO been found which are characterised in that they contain : polyethers.

Materials according to the invention are distinguished by improved mechanical propertie~, improved processability and reduced water~absorption capacity.

Materials according to the invention can contain, for ex~mple, 0.02 to 5% by weight of polyether in the har-: dened state. This amount is preferably 0.03 to 2% by weiqht, particularly preferably Q.05 to 1% by weight.

Based on the not yet hardened gypsum, for example on the20 anhydrous gyp~um or a~hydrite used, materials according to the invention can be prepared, for example, with the addition of 18 to 400% by weight of water. Thi~ amount is preferably 30 to 100~ by weight, particularly preferably 35 to 70% by weight.

Le A 28 354 w ~ _ ' ' ,' , ,. ; , ' , ,~
',.. ~ '. ' 2~710~

The polyethers can be, for example, adducts of ethylone oxide and/or propylene oxide with starter molecules containing reactive hydrogen atoms. If ethylene oxide and propylene oxide were used for adduct formation with the starter molecules, this can have taken place simultaneously ~which produces a random distribution of ethylene oxide and propylene oxide units) or in succes-sion in any desired order (which produces a block-like distribution of ethylene oxide and propylene oxide units). Mixtures of polyethers of different composition can also be used, for example mixtures of monofunctional polyethers with polyfunctional polye~her~, mixtures of random polyethers and block copolyethers or mixtures of polyethers of the formulae (I) to ( IV) . The polyethers to be us~d according to the invention can contain hydroxyl group~ and terminal groups formed by reaction of the hydroxyl yroups, for example ester, ether, urethane or caxbonate groups. Analogously, amino poly-ethers can contain amide or imide groups.

Preferred polyethers have the formulae (I) and/or (II) St~--(CH2-CH-O)a (CH2-CH2-O)~--(CH2-fH-O)C H' (1), CH3 CH3 n St ~ (CH2-fH-O)~--(CH2-CH2-O)e--Hl (Il), CH3 n Le A 28 354 - 3 '''~' ~
' 2~17~0~ :
in which St repre~ents the radical of a starter molecule, for example the radical of propylene glycol, trimethylolpropane, glycerol, ~orbitol, ethylenediamine, ~tearylamine, ammonia or hydroxyl-containing polysiloxane, n represents the number of reactive hydrogen atoms ~ originally present in the starter moleculel : a represents an integer or a fractional number from 17 to ~3, preferably 19 to 21, ~' b represent~ an integer or a fractional number from 3 to 6, preferably 3 to 4, c represents an integer or a fractional number from 1 to 6, preferably 1 to 3, d represents an integer or a fractional number from 17 to 23, preferably 19 to 22, and e represents an integer or a fractional number from 3 ; to 15, preferably 4 to 7 3 If one or more of numbers a to e represent a fractional number, these are average number~ characterising mixtures of different molecules o the formulae (I) andtor (II).

Le A_28 354 - 4 -. . .
', . .' :. ' ,; . ' .

~7~
Further preferred polyethers are products obtained by reacting vegetable or animal fat~ and oils ~= tri-glyaerides of fatty acid ) with ethylene oxide and/or propylene oxide in the pre~ence of basic catalysts.
S Examples of fats and oils which can b~ used for this are coconut butter, palm kernel oil, tallow fat, lard, rape oil, soya bean oil, sunflower oil and thistle oil.
Examples of basic catalysts which can be used for thi~
are alkaline metal hydroxides and alcoholates, in par-ticular oil-soluble alcoholates, such as potassium propylene glycolate.

If the fats and oils are reacted with ethylene oxicle and propylene oxide, products can form which a~e analogous to the formulae (I) or (II), in which ca~e n is then, however, an integer or a fractional number from 0.5 to 3 and St then represents the radical of a glycerol molecule additionally containing 2.5 to 0 fatty acid raclicals.

If the fats and oils are r!eacted only with ethylene oxide or only with propylene oxide, products of the formulae (III) or (IV) can form.

St ~ (~H2- ~H2- O)fH ¦ (Ill) Le A 28 -~54 - 5 -, ' , ~`' ' ';

St ~ ~CH2 CH - O) H1 1 g (IV) CH3 n in which St~ represents the radical of a glycerol molecule ~till containing 2.5 to 0 fatty acid radicals, ~; n' represents an integer or a fractional number from 0O5 to 3 and f and g are each an integer or a fractional number from 2 to 30, preferably 3 to 15.

If n', f and g and the number mentioned under St' are fractional numbers, these are average values characteris-ing the mixture of different moleculPs of the formulae (III) or (IV~.

The polyethers derived from vegetable and animal fats and oils can have, for example, molecular weights in the ran~e from l,000 to 3,000, preferably in the range from l,300 to 2,500.

Polyether~ to be used for the present invention are often compounds known per ~e which are commercially available or, if desired, can be prepared in a manner known per se ~ s ee, for example, German Offenlegungsschrift 2,756,770, German Offenlegungsschrift 3,330,197, US Patent Le A 28 354 - 6 -:' ;, , .. , ~71~

Specification 4,481,367, US Patent Specification2,979,528, US Patent Specification 2,674,619, US Patent Specification 3,472,781, US Patlent Specification 4,452,712, US Patent Specification 2,677,700, European Offenlegungsschrift 54,953, European Patent Specification 47,371, European Offenlegungsschrift 116,564, European Offenlegungsschrift 109,515, GDR Patent Specification 237,178, German Offenlegungsschrift 2,220t338, Macro-molecules 20, page~ 3089-3091 (19B7) and Technical Data on Pluronic~ Polyol~, a newsletter fxom ~ASF-Wyandotte Corp.)O The preparation of polyethers derived from vegetable and animal fats and oils is described above and in the examples.

The polyethers to he used according to the invention can be added to the mixing water, for example, during the production of gypsum materials. If they are present as water-soluble and/or water-dispersible solids, they can be added, for example, to the mixing water and/or to the gypsum powder. However, they can al80 be used, for example, in the form of mas~er ~atch granules together with gypsum or other powders which may be inert.

A particular embodiment of the materials according to the invention is characterised in that they additionally contain polyurethanes and/or polyurethane-urea~.
Materials according to the invention of thi~ embodiment can contain, for example, a total of 0o02 to 50% by weiyht o~ polyurethanes, polyurethane-ureas and poly-ether~ in the hardened state . This amount i3 preferably Le A 28 354 - 7 -.. :

2 ~

0O05 to 10~ by weight, particularly preerably 0.2 to 3 by weight.

Polyurethanes and/or polyurethane~ureas are in general used in the form of an aqueous dispersion or ~olution.
The Yolids content of such dispersions can be, for example, 0.5 to 50% by weight. Preferably, it is 1 to 10%
by weight. The overall amounts of water which can be used for producing the materials according to the invention of this type are as stated above. It mus~ only be erlsured that the water in this case is introduced entirely or in part in the form of the polyurethane and/or polyurethane-urea dispersion.

Polyurethanes and/or polyurethane-ureas suitable for thi~
embodiment of the present invention in general contain hydrophilic groups. These can be, for example, a) ionic groups, b) groups which can be converted into ionic groups by a neutralisation reaction and/or c) ethylene oxide units incorporated in the polyether chains present in the polyurethane or polyurethane-urea.

In principle, any cu~tomary aqueous poly-urethane(urea)dispersions which, possibly by virtue of containing alcohols, and, if desired, further organic solvents, are substantially insensitive to coagulation, are suitable. A number of processe~ for the preparation of suitable polyurethane(urea)dispersions in water are known. A comprehensive list is given, for example, by D.
Dieterich and H. Reiff in ~'Die Angewandte Makromolekulare ;

Le A 28 354 - 8 -' 2 ~

Chemie", 26, pages 85-106 (1972), ~. nieterich et al. in "Angewandte Chemie", 82, pageE 53-S3 (1970), D. Dieterich et al. in J. Oil Col. Chem. Assoc. 53, pages 363-379 (1970), D. Dieterich in "Die Angewandte Makromolskulare Chemie'l, 98, pages 133-158 (1981) and in "Chemie und Technologie makromolekularer Stoffe" [Chemistry and Technology of Macromolecular Compound~] (29th Publication of Fachhochschule Aachen on the occasion of the 9th Colloquium on 8 May 1981 at PH Aachen, Department of Chemical Engineering). Unless expressly stated otharwise, in the following the term l'polyurethane" is also under-stood to mean urea-containing pol~mers, i.e. poly-urethane-ureas.

A preferred process for preparing suitable aqueous polyurethane dispersions consists in reacting an NCO
prepolymer dissolved, for example, in an organic solvent with a chain-lengthening agent. Either the prepolymer or the chain-lengthening agent contains ionic groups or groups capable of ion formation. In the course of the polyaddition reaction or afte~wards, these groups capable of ion formation can then be converted into ionic groups.
The aqueous dispersion can be formed at the same tLme or afterwards, for example by addition of water and removal of the organic 301vent by distillation.

Further d~tails regarding the polyurethane dispersions to be used and their preparation can ~e taken, for example, from German Offenlegungsschrift 3,320,217.

Le A ?8 354 - 9 -", - . , :

~710~.

The hydrophilic or potentially hydrophilic group~ are in general pre~ent in the polyurethanes to be used in such amounts th~t dispersibility of the polyurethanes in water i5 en3ured. The hydrophilic group conte.nt of the poly-urethanes can be, for example, 30 ~o 130 milliequivalentsp~r 100 g of polyure~hane solid, if only ionic group and/or groups which can be convert~d into ionic group6 are used. If only ethylene oxide units are used as hydrophilic groups, their conten~ in l:he polyether chains can be, for example, 2 to 20% by ueight. If both types of hydrophilic groups are present, 0.1 to 40 milli-equivalents of ionic groups and/or groups which can be converted into ionic groups per lQ0 g of polyurethane solid and simultaneously 0.5 to 10~ by weight of lS polyethylene oxide units within the polyether chains are preferably present in the polyurethanes.

Instead of polyurethanes and/or polyurethane~uxeas or in a mixture with polyurethanes and/or polyurethane~ureas, other polymers can also be present in the materials according to the invention. Thus other polymers can also be in~roduced, for example, in the foxm of products known per se, such as polybutadiene, polybutadiene/s~yrene, polyvinyl ~cetate, polystyrene/(meth~ac~ylate and/or polybutadiene/styrene/acrylonitrile dispersions. In principle, aqueous dispersions of any monomers which are copolymerisable with one another are suitable, of which butadiene, styrene, acrylonitrile, various alkyl acry-lates, various methacrylates, maleic acid derivatives, olefins and other vinyl and diene monomers may be Le A 28 354 - 10 -2~7~ 0~

mentioned as mon~mers. O~ particular interest are vinyl acetate ethyl~ne copolymers and rubber lattices.
Polysiloxane dispersions con~aining, if desired, reactive groups and other reactive systems, such as polyisocyanate prepolymsrs/ unsaturated polyester resins and epoxy resins and emulsions of monomers which, after mixing wi~h gyp~um and water, can be made to react are also suitable.

Yox the preparation of these dispers:ions, the following examples of olefinically unsaturated monomers may be mentioned:

a) ~ olefinically unsaturated monocarboxylic acids having 3 to 5 C atoms and esters or nitriles and amides thereof, such as acrylic, methacrylic and crotonic acid, acrylamides and methacrylamides, ac~ylonitrile and methacrylonitrile, esters of acrylic and methacrylic acid, in particular those with saturated monohydric aliphatic or cycloaliphatic alcohols having 1 to 20 carbon atom~, such as esters of the acids mentioned with m~thyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, hexyl alcohol, 2-ethylhexyl alcohol, octyl alcohol, ~tearyl alcohol, cyclohexanol, methylcyclohexanol, further with benzyl alcohol, phenol, cresol, fur-furyl alcohol, monoesters of ~,~-monoolefinically un~aturated monocaxboxylic acids having 3 to 4 C
atom~ with dihydric saturated aliphatic alcohols having 2 to 4 C atoms, such as, for example, Le A 28 354 __ ,:

2 ~ 7 ~

2-hydro~ypropyl acrylate, 4-hydroxybutyl ~crylate, glycidyl esters of acrylic and methac~yli~ acid, ~uch as glycidyl (meth)acrylater aminoalkyl esters and aminoalkylamide~ of acrylic and methacrylic S acid, such as 2-aminoethyl (meth)acrylate hydrochloride, N,~-dimethylaminoethyl (meth)acrylate, N,N-dLmethylaminopropylacrylamide.

Monomers having two or more double bonds in ~he molecule can also be used. Examples of sui.table monomers of this type are ethylene glycol diacrylate or ethylene glycol dimethacrylate.

b~ Olefinically un~aturated dicarboxylic acids having 3 to 5 C atoms and their derivatives, such as fumaric acid, maleic acid, itaconic acid, mono- and diesters of the abovementioned dicarboxylic acids having 1 to 18 C atoms in the alcohol radical, such as dimethyl maleate, diethyl maleate, dibutyl maleate, monohexyl malea~e, monocyclohexyl maleate.

c) Mono- and diesters of vinyl alcohol with carboxylic aci~s or with hydrohalic acid~, vinyl ethers, vinyl ketones, vinylamides, such as vinyl acetate, vinyl propionate, vinyl laurate, vinyl stearate, vinyl ben~oate, chlorovinyl acetate, divinyl a~ipate, vinyl chloride, vinylidene chloride, vinyl ethyl ether, vinyl butyl ether, vinyl ethyl ether or vinyl i~obutyl ether, vinyl ethyl ketone, vinylformclmide, N-vinylacetamide.

' Le A_28 354 - 12 -, :

. ~
-, ,: ~ ,:; . . ~

2~17~0~1 d) Vinyl compoundR of aromatic and heterocyclics, such as styrene, ~-methylstyrene, vinyltoluene, p-chloro-styrene, divinylbenzene, 2-vinylpyrrolidone, 2-vinylpyridine.

e) N-MPthylol ethers of acrylami~e and methacrylamide of the gener~l formula R R

in which R represents hydrogen or methyl, Rl represents hydrogen, alkyl, aralkyl or aryl, R2 repre~ents alkyl or cycloalkyl, such as, for ex-ample, methyl, ethyl, n~propyl, isopropyl, n-butyl, isobutyl, cyclohexyl (see DE-B-1,035,363), furth~rmore the non-esterified N-methylol compounds of acrylamide and methacryl~
: 15 amide.

f) Mannich bases of acrylamide and methacrylamide of the qeneral formula Le A_28 354 - 13 -,.:. ~
. : . . ~ ~' ''' 20rlJ
CH2 C - CO- N - CH2- N ' I I ~R

in which R and Rl have the ~ame meaning as above and R3 and Rq repres*nt alkyl, cycloalkyl or together a heterocyclic radical, ~uch a~ the morpholine radi-cal. Suitable compounds of thi~ type are mentioned in DE-B-1,102,404.

g) Acrylic acid and methacrylic acid derivatives having a terminal halogenomethylcarbonyl group o the general formula O O
Il 11 CH2 =C-C-A-C-C~I2-~
R
in which R represents hydrogen or methyl, represents -NH-CHz-NH-, -NH-CO-NH-, -O-CH2-lH-O-~O-~H or -O-CH2-C~-O- and ~H3 X repre~.ents chlorine or bromine ~see BE-A 696,010)~

: Le A_28 354 - 14 , 2 ~ 7 ~

h) Allyl compounds, such as ~rially:L cyanurate, trial-lyl phosphate, allyl alcohol, allylamine.

i) Monoolefinically unsaturated aliphatic hydrocarbons having 2 to 6 C atoms, such as ethylene, propylene, butylene, isobutylene.

j) Conjugated diolefins having 4 to 6 C atom~, such as butadiene, isoprene, 2,3-dimethylbutadiene, chloro-butadiene.
k) Furthermore norbornene and hydroxymethylnorbornene.

Preferably, the following are uned:
Acrylic and methacrylic esters having 1 to 12 C atoms in the alcohol radical, acrylic acid, methacrylic acid and the C2-C4-hydroxyalkyl esters of these acids, styrene, acrylonitrile and methacrylonitrile, vinyl acatate~ vinyl propionate, vinyl chloride, vinylidene chloride, ethylene or propylene in combination with one or more of the monomers listed.

These monomers are in general (co)polymerised at tempera ture~ from 10 to 150C.

Suita~le initiators are in general 0.05 to 5% by weight, relative to the monomer~, of initiators decomposing into free radicals~ Examples of such initiators are organic peroxides, such a~, for example, lauroyl peroxide, Le A 28 354 - 15 -.
.
, .: ` , .

2~710~

cyclohexanone hydroperoxide, tert.~butyl peroctoate, tert.-butyl perpivalate, tert.-butyl perbenzoate, di chlorobenzoyl peroxide, benzoyl peroxide, di-tert.-butyl peroxide, tert.-butyl hydroperoxide, cumine hydro-peroxide, peroxycarbonates, such a diisopxopyl peroxydi-carbonate, dicyclohexyl peroxydicarbonate, diisooctyl peroxydicarbonate, sulphonyl peroxide-s, such as acetyl-cyclohexylsulphonyl peracetate, sulphonyl hydrazides, azo compounds, such a9 azodiisobutyronitrile and water-soluble azo compounds, such as described, for example, inGerman Auslegeschrift 2,841,045.

Inorganic peroxides, such as hydrogen peroxide, pota~ m peroxodisulphate and ammonium peroxodisulphate are also suitable.

The initiators decomposing into free radicals can be used alone or elRe in combination with reducing agents or heavy metal compounds. Examples of such compounds are sodium pyrosulphite ox potassium pyrosulphite, formic acid, ascorbic acid, thiourea, hydrazine and amine derivatives, Rongalite. The heavy me~al compounds can be present either in oil-soluble or in water-soluble form.
Examples of water-soluble heavy metal compounds are silver nitrate, halides or sulphates of di- or trivalent iron, cobalt, nickel, salts of titanium or vanadium in low oxidation states. Examples of oil-soluble heavy metal ; compounds are cobalt naphthenate or the acetylacetone complexes of vanadium, cobalt, titanium, nickel or iron.

Le A 28 3S4 - 16 -.

~ID7~ 05~

The polymerisation is in general carried out at a pH of 2 to 10, preferably 4 to 9, whil~ a pH of below 7 is preferred when cationic oligourethanes ar~ u~ed and a pH
of above 6 for anionic oligourethanes. The pH is ad~usted within the ranges mentioned often by ~he addition of aqueous ammonia if acid groups are pre~ent in the reac-tion mixture.

The molecular weights of the polymers can be regulated by using conventional regulators, for example n-dodecyl-thiol, t-dodecylthiol, diisopropyl dixanthate, thioglycol and thioglycerol. They are in general added in amoun~s of - 0.1 to 2~ by weight, relative to the monomer mixture.

The emulsion polymerisation in aqueous medium can be carried out by known polymerisation processes either batchwise or ccntinuously or by the feed process.

The continuous and the fead process are particularly preferred. In ~he latter, water is initially introduced under a nitrvgen atmosphere together with a portion or the entire emulsifier system and, if desired, a portion of the monomer mixture, the mixture is heated to the polymerisation temperature, and the monomer mixture and the initiator and, if de~ired, emulsifier are added dropwise over a period of 0.5 to 10 hours, preferably 1 to 6 hours.

After a certain period, the mixture is reactivated, and the reaction is completed until a conversion of about L~L~ 17 -' ~:. , ~.
,, 2~710~

9g.0~ to 99.9% by weight has been reached. Re~idualmonomers and any organic solvent still pre~ent can be removed after the emul3ion pol~merisation, if desired to~ether with the water present or a portion thereof, by distillation in vacuo. Then, if des:Lred, further water can be added, ultimately resulting in 10 to 60% strength by weight, preferably 20 to 50% ~3trength by weight dispersions, as the process product.

Depending on the reaction conditions, the average par-ticle diameters measured by laser scattered light cor~
relation spectroscopy are between 20 and lO00 nm, preferably between 50 and 500 nm. Dispersions having particle sizes of below 50 nm appear transparent/ while those having larger particle~ appear increasingly cloudy.

The dispersions can be blended with dispersions of the same charge, such as, for example, with polyvinyl acetate, polyet~ylene, polystyrene, polybutadiene~
polyvinyl chloride and polyac~ylate dispersions.

Finally, fillers, plasticisers, pi~ments, hydrofluoric acid and silicic acid sols, aluminium and clay disper-sions can also be incorpora~ed.

Polymers other than polyurethanes a~d/or poly-urethane-ureas can al~o be used, for example in the form of aqueous dispersions having a solids content of 1 to 50% by w~ight and in such amounts that, relative to the hardened material, 0.02 to 50% by weight of Le A 28 354 - 18 -2~051 polyurethanes, polyurethane-ureas, polyethers and/or other polymers are present.

Materials according to the invention can be prepared, for example, by first mixing water and polyether or an 5 aqueous polymer di~persion, polyether and, if desired, water in the desired amount~, then adding the de~ired amount of gyp5um to this mixture with stirring, and allowing the mixture then present to har en, i desired with shaping. Examples of suitable temperatures for the preparation of the mixture of the components are 10 to 40C, for the hardening 10 to 70C. If desired, mixi.ng of polyether and gypsum can be ~ollowed by deaeration under vacuum, if appropriate using a polymer dispersion or water, in order to remove air inclusions. Gypsum can be used, for example, in the form of anhydrous gypsum or anhydrite.

Materials according to the invention prepared in this manner and possibly present in a certain shape can be, for example, filed, worked with a knife, ground, sawed, bored, coated and metallised. They are nonflammable. Upon treatment with water, these materials absorb water which they release again virtually completely upon drying in air. Upon storage in water, in particular polymer-containing materi~ls according to the invention substantially retain their strength, whereas a moulded article stored in water and produced only from gypsum disintegrates upon exposure to the slightest mechanical stress.

Le A 28 354 - 19 _ " . . , 2~7~0~1 Material~ according to the in~ention are suitable, for example, for the production of slabs for use in the building ~ector. If desired, for example, fillers and/or dyestuffs can be added to the materials. Examples of S suitable fillers are: in each case, up to 10% by weight, but no~ more than a total of up to 50% by weight (rel-ative to the entire mixture) of Kieselgur, ground pumice, carbon black, prepared chalk, ground slate, glass wool, aluminium powder, silicate materials ~e.g. clay), alumino~ilicate&, kaolins, finely d:ivided mica, glassfibres, cotton fibres, polyamide fibxes, polyacrylo-nitrile fibres, cellulose fibres, polyester fibres, wood flour, cotton linters, polymethylene-ureas, titanium dioxide, hydrated alumina, ~inely divided lead, lead oxides, iron oxides, azulmic acid, starch and~or paper, in particular defibred waste paper. Examples of suitable dyestuffs are: azo, anthraquinone, pigment and phthalo-cyanine dyestuffs and optical brighteners and fluorescent and/or luminescent dyestuffs.

The slabs made from the materials according to the invention can be, for example, bonded or covered wi~h tiles~ veneers and/or plastics when used in the building sector. Moreover, they have excellent heat-insulating propertiPs.

Materials according to the invention can also be used in the building sector for improving plasters, mortars, insulating materials or other construction materials.

L~ A 28 354 - 20 2~71051 Polymer-containing materials according to the invention are especially also suitable for casts in medical application~. For this purpose, for example, commercially available gypsum bandages can be impregnated with an aqueous polymer dispPrsion and a polyether polyol and the cast can then be manufactured by cust:omary techniques.

Furthermore, materials according to the invention are suitable for improving gypsum moulds, or example with respect to their mechanical stability.

It i~ highly surprising that material~ according to the invention in general constitute a homogeneous material and have reproducibly improved mechanical properties (for example bending resistance and co~pressi~e strength). The use of hydrated yypsum as iller for polymexs, which is known per se, does not result in analogous improvements in properties. If aqueous polymer dispersions and hydrated gypsum are used for ~he production of materials for the purpose of co~parison~ and the water is allowed to evaporate, an inhomogeneous ma~erial with respect to the breaking resistance compared with the unfilled polymer is obtained.

The same negative result is obtained if a polymer sheet of excellent mechanical properties is dissolved in a mixture of toluene and i opropanol, anhydrous gypsum is added to this solution, and the amount of water in ethanol neces ary for setting the gypsum is added. In this case, the mixture is first homogeneous, but after Le A 28 354 .

2~7~

evaporation of the solvent a brittle, inhomogeneou~
polymer/gypsum material without any mechanical s~rength i~ obtained.

The ~act that the setting time~ of polymerJgyp~um mate-rials can be regula~ed accordin~ to the invention by additions of alcohol is also highly surprising. Thus, upon mixing 10~ g of snhydrou6 gypsum with 100 g of a 50%
strength by weight polyurethane-urea dispersion in 20 ml of ethanol, a homogeneous mixture is obtained which after being poured onto a plastic slab sets within 15 minutes.
After 2 days, the material reaches its final properties with respect to breaking and water resistance. In con-trast, if 100 g of anhydrous gypsum are mixed with 100 g of the same 50% strength by weight polyurethane disper-sion without the addition of ethanol, the material setssimilarly to pure gypsum after as little as 3 minutes.
After 2 days, the material thus obtained has reached its final properties, which differ only a little from that of a slab whose setting has been delayed by means of ethanol.

The examples which follow illustrate the present inven-tion in more detail.

Polyether (PE) useds Le A 28 354 - 22 -.

.

~71~

Polyether of the formula (I~ ~tartecl with trLmethylol-propane haYing an a of 19, b of 3, c of 104, an OH number of 40 and a molecular weight of 4000 S PE ~

Polyether of he formula (II) started with propylene glycol having a d of 20~ e of 4, an OH number of 41 and a molecular weight of 2750.

Polyether of the ~ormula tII) started with propylene glycol having a d of 20, e of 5, an OH number of 40 and a molecular weight of 2800.

Polyether of the formula (I) started ~ith glycerol having an a of 19, b of 3, c of 1.4/ an OH number of 41~6 and a molecular w~ight of 4500.

Polyether of the formula ( I 3 star~ed with trimethylol-propane having an a of 18, b of 3, c of 2.~, an OH number of 42.5 and a molecular weight of 4000.

~e A 28 354 ~ 23 -_ :

:; , .
.

-2~71~

Polyether of the formula (I) started with trimethylol-propane having an a of 17.5, b of 4.4, c of 1.3, an OH
number of 41.5 and a molecular weight of 4000.

Polyether of the formula (I) star~ed with propylene glycol having an a of 18.5, b of 2.9, c of 1.3, an OH
number of 44.2 and a molecular weight of 2500.

In an autoclaYe equipped for ethoxylations, 9 g of sodium hydroxide powder were added to 850 g of rape oil, and the mixture was dried ~y heating to 130C in vacuo. 594 g of ethylene oxide were then metered in with thorough stirr-ing. The first portions of ethyle~e oxide were added slowly, and the rest, after the reaction had started, swiftly. The reaction took a total of 5 hours. The produc~ thus obtained was washed once at 85C with on~
litre of a 1% strength sodium sulphate solution and twice with 500 ml each time of water, ~he oil was then separated off and dried in ~acuo. The product thus isolated contained 41~ by weight of ethylene glycol ether groups, relative to the rape oil.

Le A 28 354 - 24 -' ,.
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700 g of CQCOnut butter were initially introduced into a stirred autoclave and melted by heating to 100C. By applying a vacuum at the ~me time, the coconut butter and the apparatus were completely dried. S0 g of potas-sium propylene glycolate solution were ~hen added. The latter had heen obtained by dissolvi.ng 7 g of potassium h~droxide in 60 g of propylene glycol. and dis~illing off water and excess pxopylene glycol at a slight vacuum.
After heating of the batch t~ 125C under nitrogen, 870 g of propylene oxide were run in with thorough stirringl while maintaining a pressure of less than 3 PA. .~t the end of the reaction, it was allowed to continue at 125C
for another hour, until the pre~sure had dropped.
The oil obtained was washed, dried and isol~ted as described in detail under PE 8. ~he propylene glycol ether content of the product was 124% by weight, relative to the coconut butter used.

Example 1 1O3 g of polyether PE 1 were added to 500 g of deionised water, and the mixture was stirred at 420 rpm for 15 minutes. 800 g of commercially available anhydxous : moulding plaster were added, the reaction mixture was stirred for another 30 seconds and then cast in~o moulds.
Aftex a residence time of 1 hour, the moulded articleR
(dimensions: 160 x 40 x 40 mm) were removed from the moulds, then stored at room temperature for ~ hours, a~

Le A 2B 354 25 -.. . .
,, '~, ' , 2Q~3~1 40C for 48 hours and after cooling to room temparature for ~nother 18 day~, After thi~, the moulded article~ had the following properties:

Bending ~trength in accord~nce wi~h ~IN 1164: 7.1 N/mm2 Compressive strength in accordance with DIN 1164:
94.8 N~mm2 Water absorption after 20 minutes: 34.0 g ~specimen placed upright in water).

Th~se methods of measurement were used in all examples.

Comparative Example 1 A moulded article produced under otherwise identical conditions but without addition of ~he polyether had the following properties:

Bending strength: 5.8 N/mm2 Compressive strength: 85.9 N/mm2 Water absorption after 20 minutes: 45.3 g.

Examples 2 to 4 The procedure of ~xample 1 was repeated, except ~hat different ~mounts of polyether PE 1 ~ere used. rhe moulded articles obtained had the ollowing proper~ies:

Le A 28 354 - 26 .~

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Ex- Poly~ther Bending Compressive Water ample strength strength absorption No. (g) (N/mm ) (N/mm ) ~g~
2 0.~5 6.2 ~6.7 36.4 3 2.6 6.7 91.6 33.2 4 5.~ 6.6 88.3 32.2 Examples 5 to_8 The procedure of Examples 1 to 4 was repeated, except that polyether P~ 2 was used, giving moulded articles having the properties listed below:

Ex- Polyether Bending Compressive Water ample s~ren~th s~rength absorption No. (g) (N/mm2) (N/mm ) (g) 0.65 7.1 86.5 36.2 6 1.3 7.4 89.3 33.6 7 2.6 7.4 88.5 33.5 8 5.2 6.5 87.3 32.8 ExamPles 9 to 13 The procedure of Examples 1 to 4 was repeated, except th~t commercially available stucco was used instead of the moulding plaster. The moulded articles obtained had the following properties:

Le A 2B 354 - 27 -: ' .`: , : . . -2~7~0~

Ex- Polyether Bending Compressive Water ~mple stren ~ h streng~h ab~orption No. (g) ~N/mm ) (N/mm ) (g) 9(PE 1)0~8 6.7 92.7 74.3 lO(PE l)l.~ 6.7 92.1 25.3 11(PE ~)0.5 fi.9S 84.2 29.1 12(PE 2)1.0 7.05 92.7 26.2 13(PE 2)2.0 6.15 90.1 26.0 ComParative Example 2 The procedure of Examples 9 to 13 was repeated, except that no polyether was added, giving moulded articles having the properties listed below:

Bending strength: 6.0 N/mm2 Compressive strength. 77 N/mm2 Water absorption after 20 minutes: 40.2 g Example 14 The procedure of Example 1 was repeated, except that 40 g of a 50~ strength by weight aqueous polyurethane disper-sion was added to the mi~ture before adding ~he mouldingplaster, and the mixtur~ was stirred for another 2 min-utes, giving moulded articles having the following properties:

Bending strength: 8.8 N/mm2 ~5 Compressive strengths 112.4 ~/mm2 :
., . ~, Le A 23 354 - 2B
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Water ab~orption after 20 minutes: 24.9 g.

Examples 15 to 29a The procedure a~ described in Example 14 was repeated, except that the polyurethane dispersion was u ed in varying amounts and various polyethers were used in varying 2~nounts.

Le ~ 28 354 - 29 -.

.

Ex- Poly- Poly- Poly- Bendin~ Compres- Water ample urethane ether ether ~rens~th s ive absorp-~ % by ( 9~ by strength tion weight weight 5solid/ (type) 601id/ (N/mm2) (N/man2) ~g) solid) ~ solid) ) __ ______~_____~_~_______________ ____________ .
1 PE 1 0 .15 7 . 9 112 O 4 24 . 4 16 1 PE 1 0 . 08 g . 9 111. 6 25 . 3 17 5 PE 2 0 .15 8 . 8 104 . 8 18 . 8 18 5 PE 2 0.80 9.0112.3 17.~
l9 5 PE 1 0 .15 11. 3 115 . 5 20 . 8 PE l 0.80 9.7104.8 19.4 21 1 PE 1 0.15 8.0108.7 25.8 22 2.5 PE 1 0.15 8.3lO9.0 21.4 23 5 PE 1 0.08 8.~l98.3 21.4 24 5 PE 4 û.û8 9.593.0 23.3 PE 5 0.08 9.5100.4 21.4 26 5 PE 6 0.08 8.4103.4 22.0 27 5 PE 3 0 . 08 8 . 0 102 . 2 23 . 0 28 5 PE 7 0 . 08 8 . 3 103 . l 22 . 0 29 0 .15 - - 5 . 985 . 8 42 . 2~for 29a 1 - - 5 . 970 .1 32 .4~,c~
IE~ ' ~ssrl _ solid/solid here and in the tables below denotes polyuxethane or polymer or polyether in Pach case calculated as anhydrous substance, relative to ~psum.

Le 1~ 28 354 30 -"

.
.: i Exam~les 30 to_34 ~7~

The procedure as described in Example 14 was repcated, except ~h~t polyethers PE 8 and PE 9 and commercially availahle stucco were u~ed instead of moulding plaster.

Ex- Poly- ~oly- Poly- BendingCompres- Water ample urethane ether ether strenqth sive absorp-(~ by (% by strength tionweight w~ight solid~ (type) solid/ (N/mm2) (N/mm2) ~g) solld~ solid) .
1.5 PE 90.02 7.6111.0 18.0 31 PE 90.02 8.197.0 2~.3 32 1.5 PE 80.02 7.91111.0 18.2 33 - PE 80.02 6.689.0 32.4 34~ 6.378.2 39.1 for comparison Examples 35-40 The procedure as described in Example 14 was repeatedl except that other polymer dispersions were used instead of the polyurethane dispersion and commercially available stucco was used instead of moulding plaster.

Polymer t~pe 1 was a dispersion containing polybuta-diene~styrene.

L.e A 28 354 - 31 -,.
, 2 ~ 7 ~
Polymer type 2 was a dispersion containing poly6tyreneJbutyl methacrylate.

x~ Poly- Poly~ Poly- BendingComp.res Water ample mer ether ether streng~h ~ive absorp-(% by (% b~ strength tion weight weigh~
solid/ (type) solid/ (N/mm2) (N/mm2) (g) solid) solid) _ 1/2 . 5 P~ 1 0 . 15 7 . S 104 . ~ ~ 1 . 3 36 1/2 . 5 PE 2 0 .15 7 . 6 101. 7 23 . 6 37 1/~ . 5 PE 9 0 o 15 7 . 7 102 .1 22 . 3 38 2/2 . 5 PE 1 0 .15 7 . 9 106 . 3 22 . 5 39 ~/2 . 5 PE 9 0 .15 7 . 8 105 . 0 23 .1 ) ~ 6 . 3 ~8 . 2 3g . 1 for comparison Examples 41 to 4 5 The procedure as described in Example 14 was repeated, except that polyethers PE 8 and PE 9 were used and a polyurethane dispersion obtained in the following manner was used in Examples 41 and 43.

0.25 mol of butoxyethoxybutanol (OH number 40), 0.25 mol of propylene oxide polyether (MW 1000), O.40 mol of monosulphonsted 1,4-butanediol, 1.2 mol of isophorone diisocyanate and 0.20 mol of hydroxyethylethylenedi~mine were reacted with one another to give a polyurethane dispersion ~ontaining 68~ by weight of water.

Le A 28 354 - 32 -~710~1 Ex~ Poly- Poly- Poly- ~ending Compres~ Water ample urethane ether et;he:r s ~xength sive absorp-( % by ( % by s~rength tion weight weight 5solid/ (type) solid/(N/lluna) (N/mm2) (g~
solid) ~olid) 41 0.56PE 9 0.02 7.6 112.3 1~.3 42 - PE 9 0.02 8.0 98.0 2g.5 43 0 . 58 PE 8 0 . 02 7 . 75 111. 2 19 . 2 44 - PE 8 0.02 6.5 88.0 31.1 45 ~ - - - 6 . 378 39 _ for comparison .

Claims

1. A gypsum based Material containing organic addi-tives and a polyether.

2. A material of Claim 1, which contains in the hardened state 0.02 to 5% by weight of polyether.

3. A material of Claim 1, in which the polyether is one of the formulae (I) and (II) (I), (II), in which St represents the radical of a starter molecule, n represents the number of reactive hydrogen atoms originally present in the starter mole-cule, a represents an integer or a fractional number from 17 to 23, b represents an integer or a fractional number from 3 to 6, c represents an integer or a fractional number from 1 to 6, d represents an integer or a fractional number from 17 to 23 and e represents an integer or a fractional number from 3 to 15, or were obtained from vegetable or animal fats and oils by reaction with ethylene oxide and/or propy-lene oxide in the presence of basic catalysts.

4. A material of Claim 1, which additionally contains a polyurethane and/or a polyurethane-urea.

5. A material of Claim 4, which contains in the hardened state a total of 0.02 to 50% by weight of polyurethane, polyurethane-ureas and polyethers.

6. A material of Claim 1, which contains polymers other than polyurethanes and/or polyurethane-ureas.

7. A process for the production of a material of Claim 1, in which, relative to not yet set gypsum, 18 to 400% by weight of water, relative to the hardened material, 0.02 to 5% by weight of poly-ether and polyurethanes, polyurethane-ureas and/or other polymers are mixed in such amount that, relative to the hardened material, a total of 0.02 to 50% by weight of polyurethanes, polyurethane-ureas, polyethers and other polymers are present, and not yet hardened gypsum is added, and the mixture is allowed to harden.

8. A process of Claim 7, in which polyurethanes, poly-urethane-ureas and/or other polymers are used in the form of an aqueous dispersion having a solid content of 1 to 50% by weight.

9. A process of Claim 7, in which mixing is carried out at 10 to 40°C and hardening at 10 to 70°C.

10. A process of Claim 7, in which the mixture is allowed to harden with shaping.

11. The method of using the material of Claim 1 or pro-duced according to Claim 7 as slabs in the building sector and for improving plasters, mortars, insula-ting materials and other construction materials, casts and/or moulds.