IL47584A - Urea copolymer compositions containing silica fillers - Google Patents

Description

UREA COPOLYMER COMPOSITIONS CONTAINING SILICA FILLERS u.

This invention relates to new polymer compositions and more particularly to new polymer compositions based on organic polyisocyanate derived products containing silica fillers.

It has previously been proposed in UK Patent Specification No.1186771 to prepare silicious materials by reaction of aqueous solutions of alkali metal silicates with organic polyisocyanates optionally in the presence of low molecular weight polyols.

However this procedure gives materials of relatively poor properties i.e. they were brittle and of low strength. This disadvantage is described in UK Specification 1385605 where the limitation of the polyisocyanate/alkali metal silicate compositions is, at least in part, ascribed to a failure to obtain a fine dispersion of the tv/o components. Specification No. 385605 proposes the use of prepolymer - - ionomers to prepare fine emulsions with aqueous alkali-metal silicate solutions which then react to give materials of good strength and elasticity.

We have found that unfoamed polymer compositions of the above type, that is polymers containing polyurea units derived , .! from the reaction of water and a polyisocyanate and incorporating a silica filler can be obtained without the need for special materials such as ionomers by the use of readily available isocyanate reactive compounds other than low molecular weight polyols viz relatively high molecular weight polyols or tars or pitches in conjunction with the polyisocyanate and alkali metal silicate solution. The. polymer compositions of the present invention have good mechanical properties which may be varied over a v/ide range by choice of the isocyanate reactive compound.

According to the present invention there is provided a process for the manufacture of solid unfoamed urea copolymer compositions containing silica, which comprises forming an oil and water emulsion wherein the water phase comprises an aqueous solution of an alkali metal silicate and the oil phase comprises a mixture · -· of an organic polyisocyanate and an organic isocyanate-reactive polyol of molecular weight at least 1+00 or an isocyanate reactive tar or pitch, in which the NCO to ieocyanate Reactive group ratio is greater than 1, or the reaction product of an excess of an organic polyisocyanate with such an organic isocyanate reactive polyol or tar or pitch, whereby reaction takes place between NCO groups and water at the oil/water interface and evolution of carbon dioxide is prevented by reaction with the silicate, with consequent formation of silica.

Du.2?Hf3 In the preceding paragraph the oil phase of the emulsion is defined in one possibility as a mixture of organic polyisocyanat and an organic isocyanate-reactive compound of molecular weight at least i+00 or an isocyanate reactive tar or pitch and it should be noted that the term "mixture" includes both homogeneous and heterogeneous mixtures. Thus the emulsion described may have an aqueous phase and a single oil phase or the oil phase may be two mutually immiscible oil phases if the organic polyisocyanate and organic isocyanate-reactive compound are not mutually soluble.

The nature of the emulsions is described in more detail at a later part of the specification.

As organic polyisocyanates, there may be used, e.g., aliphatic diisocyanates such as hexamethylene diisocyanate, tetramethylene diisocyanate, 2,2,If- and 2,l.,i+-trimethyl hexamethyle diisocyanates, aromatic diisocyanates such as tolylene-2,l-diisocyanate, tolylene-2,6-diisocyanate, diphenylmethane-i+,I.' -diisocyanate, 5-methyl-diphenylmethane-!+, '-diisocyanate, - and £-phenylene diisocyanate, chlorophehylene-2:l+-diisocyanate, xylylene diisocyanate, naphthalene- :5-diisocyanate, diphenyl- It'-diisocyanate, if:V-diisocyanate-3:3'-dimethyldiphenyl and diphenyl ether diisocyanate and cycloaliphatic diisocyanates such as dicyclohexylmethane diisocyanates, methylcyclohexylene diisocyanates and 3-isocyanatomethyl-3v5»5-trimethylcyclohexyl isocyanate. Triisocyanates which may be used include aromatic, triisocyanates such as 2:lj.:6-triisocyanatotoluene and triisocyanatodiphenyl ether. - k - Du.271l3 There may also be used uretedione dimers and isocyanurate polymers of diisocyanates, for example, tolylene-2,tf-diisocyanate, tolylene-2,6-diisocyanate and mixtures thereof, and the biuret polyisocyanates obtained by the reaction, of polyisocyanates with water.

Mixtures of polyisocyanates may be used, including the mixtures obtained by the phosgenation of the mixed polyamines prepared by the reaction of formaldehyde with aromatic amines such as aniline and orthotoluidine under acidic conditions.

An example of the latter polyisocyanate mixture is that known as crude MDI, which is obtained by phosgenation of the mixed polyamines prepared by the reaction of formaldehyde with aniline in the presence of hydrochloric acid and which consists of diphenylmethane-l,!*.'-diisocyanate in admixture with isomers thereof and with methylene-linked polyphenol polyisocyanates containing more than two isocyanate groups.

It is preferred to use essentially pure diphenylmethane diisocyanate particularly the i+,i '-isomer when elastomeric products are required.

• It is preferred to use crude MDI, if rigid products are required.

Any isocyanate reactive polyol of molecular weight of at least iOO or isocyanate ' reactive tar or pitch may be used in the process of the present invention providing that, in the form it is to used i.e. as itself or after reaction with the polyisocyanate, it will result in a satisfactorily stable fine emulsion with the silicate. -solution. In general this means that the above mentioned isocyanate Du.271if3 reactive compounds should have a low solubility in water and a hydrophobic character. This requirement is often a little less stringent when the polyol is reacted with excess polyisocyanate before emulsification but in this case also it is generally preferred that it should have a hydrophobic character.

A preferred embodiment of the present invention utilises organic isocyanate reactive polyols of molecular weight at least 1+00. Thus according to this preferred embodiment there is provided a process for the manufacture of solid unfoamed urea-urethane copolymer compositions containing silica, which comprises forming an oil and water emulsion wherein the water phase comprises an aqueous solution of: an alkali metal silicate and the oil phase comprises a mixture of an organic polyisocyanate and an organic isocyanate-reactive polyol of molecular weight at least i+00, in which the NC0:0H ratio is greater than 1, or the reaction product of an excess of an organic polyisocyanate with such an organic polyol, hereby reaction takes place between NCO groups and water at the oil/water interface, and evolution of carbon dioxide is prevented by reaction with the silicate, v/ith consequent formation of silica.

The nature of the polyol determines the character of resulting copolymer compositions according to relationships well known in the polyurethane art e.g. linear polyols of high molecular weight usually give elastomer products and branched polyols of lower molecular weight give rigid products.

As examples of polyols for use in the present invention there may be mentioned polyesters and polyesteramides such as those obtained by known methods from carboxylic acids, glycols and, Du.271i+3 as necessary, minor proportions of diamines or amino alcohols.

Suitable dicarboxylic acids include succinic, glutaric, adipic, suberic, azelaic, sebacic, phthalic, isophthalic and terephthalic acids and mixtures of these. Examples of dihydric alcohols include ethylene glycol, 1 :2-propylene glycol, 1:3-butylene glycol, 2:3-butyleneglycol, diethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol and 2:2-dimethyltriraethylene glycol. Suitable diamines or amino alcohols include hexamethylene diamine, ethylene diamine, mono-ethanolamine and phenylene diamines. Mixtures of polyesters and polyesteramides may be used if desired. Small proportions of polyhydric alcohols such as glycerol or trimethylolpropane may also be used, in which case branched polyesters and polyesteramides are obtained.

Preferred polyesters for use with the process of the present invention are those of molecular weight 1000-2000 in particular poly(ethylene adipate), poly(ethylene/propylene adipate), poly(tetramethylene adipate) and poly(ethylene/tetramethylene adipate).

As examples of polyols for use in the present invention there may also be mentioned polyethers such as polymers and copolymers of cyclic oxides, for example 1 :2-alkylene oxides such as ethylene oxide, epichlorohydr n, 1 : 2-propylene oxide, 1:2-butylene oxide and 2:3-butylene oxide, oxycyclobutane and substituted oxycyclobutanes and tetrahydrofuran. There may also be mentioned polyethers obtained by the polymerisation of an alkylene oxide in the presence of a basic catalyst and ¾ater, polyols such as ethylene glycol, propylene glycol, glycerol, trimethylol propane, triethanolamine or Du.2711 amines such as aniline, tolylene diamine, aniline/formaldehyde ■ condensates such as those used as precursors of pure MDI, and ethylene diamine. It will be appreciated that polyethers may be linear i.e. polyether diols or branched i.e. polyether triols, tetrols, etc. depending on the functionality of the polyol or amine used for reaction with the alkylene oxide.

Polyethers for use in the process of the present invention usually do not have a large part, if any, of their structure provided by units derived from ethylene oxide since such units confer a generally undesirable hydrophilic character to the polyether.

Preferred polyethers are derived from alkylene oxides having three or more carbon atoms per molecule. Especially preferred are polyethers derived from 1 : 2-propylene oxide or from tetrahydrofuran.

Polypropylene polyether glycols of molecular weight -j.00-2000 are a particularly preferred class of polyethers, with molecular weight of 1000 being especially preferred.

A further preferred class of polyether diols are poly(tetrahydrofurans) of molecular, weight 1000-2000.

Another particularly preferred class of polyethers are branched polyethers from 1 :2-propylene oxide. Especially preferred are polypropylene polyether triols with molecular weights of iOO-3000. Such triols are obtained from the alkaline polymerisation of propylene oxide in the presence of glycerol, trimethylol propane, triethanolamine and hexane triols.

Another preferred polyol is castor oil.

Du.271l3 A further class of preferred polyols are hydroxylated polybutadienes e.g. the products of free radical or anionic polymerisation of butadiene under such conditions that a plurality of hydroxyl groups are introduced into the polymer molecule. It is particularly preferred that such products have molecular weights of -+00-1*000 especially 2000 to JOOO.

Other polyols which may be used in the process of the present invention include, epoxy resins which also contain isocyanate-reactive groups, for example, the hydroxyl group-containing products obtained by reaction between diphenylolpropane and epichlorohydrin, drying oil and non-drying oil modified alkyd resins, hydrogenated castor oil and the reaction products of castor oil, hydrogenated castor oil and mixtures thereof with a hard resin, defined as a rosinate of a metal selected from Group Ila of the Periodic Table or a condensation product of rosin with (i) at least one .polyhydric alcohol or (ii) at least one polyhydric alcohol and at least one optionally substituted phenol/formaldehyde resol resin, or (iii) at least one polyhydric alcohol and at least one α,β-unsaturated dicarboxylic acid or the anhydride thereof.

Another preferred embodiment of the present invention utilises an isocyanate reactive tar or pitch. Thus according to this preferred embodiment there is provided a process for the manufacture of solid, unfoamed urea copolymer compositions containing silica, which comprises forming an oil and water emulsion wherein the water phase comprises an aqueous solution of an alkali metal silicate and the oil phase comprises a mixture of an organic polyisocyanate and an isocyanate-reactive tar or pitch, in which the NCO to isocyanate reactive group ratio is greater than 1, or the reaction product of an excess of an organic polyisocyanate with such a tar or pitch, whereby reaction takes place between NCO groups and water at the oil/water interface, and evolution of carbon dioxide is prevented by reaction with the silicate, with consequent formation of silica.

Tars and pitches containin isocyanate reactive groups suitable for use in the process of the present invention are defined and described in detail in UK Specification N0.IO38OO9. Particularly valuable for use in the process of the present invention are the tars resulting from the destructive distillation of coal i.e. coal tar and especially valuable are the pitches formed when these tars are themselves distilled i.e. coal tar pitch.

Products of the process of the present invention incorporating tars and pitches are associated with especially good resistance to water, decay-producing organisms and vermin. They also frequently show advantages of relatively low cost.

In the above preferred embodiment which utilises an isocyanate reactive tar or pitch an isocyanate reactive polyol of molecular weight at least l+OO may optionally be also incorporated in the composition at any stage at which isocyanate groupe are present to react with the said polyol. For example the polyol may be preblended with the tar or pitch. Alternatively both isocyanate reactive polyol and the isocyanate reactive tar or pitch may be added separately to the silicate solution and polyisocyanate at any stage during the formation of the emulsion. It may be convenient to Du.271tf3 react either the tar or pitch or the polyol with excess polyisocyanate before incorporating into an emulsion with silicate solution,., and the other of the tar or pitch or polyol. Also both may be reacted with excess polyisocyanate prior to emulsification with silicate solution* ΐ ,.¾_. Where the process specifies an excess of polyisocyanate it will be understood that this means an excess over the amount needed to react with both the polyol and the tar or pitch.

Any of the polyols of molecular weight at least -OO mentioned earlier may be used in the above process providing that it is or becomes during the process compatible with the tar or pitch.

Polyols are, in general, more likely to yield compatible systems with the tar or pitch if first reacted with excess polyisocyanate.

The compositions produced by the process of the present invention may also contain other fillers, for example, talc, china clay, barytes, asbestine, mica, zinc stearate, slate powder, wood flour, sawdust, vermiculite, wood chips, glass fibre, power station fly ash, expanded clay, marble and other naturally or artificially coloured sands, stones, flint or rocks, inorganic pigments such as red iron oxide, titanium dioxide and chrome pigments, organic pigments such as azo pigments and pigments based on phthalocyanine, and synthetic organic polymers which may be thermoplastic or thermosetting polymers or copolymers, for example, nylon polymers, polyvinyl chloride, polyvinyl chloride/polyvinyl acetate copolymers, urea/formaldehyde polymers, acetal polymers and copolymers, acrylic polymers and copolymers, acrylonitrile/butadiene/styrene terpolymers, cellulose acetate, cellulose acetate butyrate, polycarbonates, Du.271½3 polyethylene terephthalates, polystyrenes, polyurethanes, polyethylenes and polypropylenes. These polymers may be vinpigraented or mass pigmented and may be incorporated into the composition in the form of powders, lumps, turnings, fibres, flakes, tapes or film.

Any of the components used to form the emulsion in the process of the present invention may also contain a catalyst known to catalyse the reaction between isocyanate groups and hydroxyl groups. Included among such catalysts are organometallic compounds, metal salts and tertiary amines, specific examples of which are dibutyl tin dilaurate, tetrabutyl titanate, zinc octoate, zinc naphthenate, stannous octoate, stannic chloride, ferric chloride, lead octoate, potassium oleate, cobalt 2-ethylhexoate, Ν,Ν-dimethyl cyclohexylamine, N,N-dimethylbenzylamine, N-ethylmorpholine, 1 ,i-diazobicyclo-2,2,2-octane, l-di'methylaminopyridine, oxypropylated triethanolamines, β-diethylarainoethanol and Ν,Ν,Ν' ^'-tetrakis (2-hydroxypropyl)ethylenediamine.

The alkali metal silicates used are preferably potassium or, even more preferably, sodium, silicates. 'They can be represented by the formula Me^.xS O^ wherein Me is the alkali metal and x is the molar proportion of-SiC^ to'Me^O* In the case- of potassium silicate x preferably varies from I.I4.3 to 2. 8 and in the case of sodium silicate values of x from 1.6 to 3·3 are preferred. The solution used may contain from 1 to 9 by weight of alkali metal silicate, preferably^ 35~60$ for .sodium, 27-52$ for potassium, v If- desired, the alkali metal silicate solution used may be formed in situ e.g. by adding a soluble alkali metal silicate' owder and water to a polyol with agitation whereby the silicate dissolves in the water before, during or after its. emulsification in the polyol.

- - Du.27T3 The proportion of the combined weight of polyisocyanate plus polyol or tar or pitch which is polyol or tar or pitch may vary widely. It will not usually be less than 2.5% and may. be as high as 5$ e.g. when elastomeric products are being formed from polyols of high molecular weight such as diols of molecular weight 10,000.

The mixing of. the components to produce the emulsion may be carried out by methods known in the art. The degree of mixing necessary to produce a fine emulsion will vary with the nature of the components. In some instances simple agitation is sufficient but in others high speed high shear mixing may be needed. The addition of emulsifying agents e.g. non ionic types such as ethylene oxide/propylene oxide block copolymers may be beneficial but is seldom necessary.

Microscopic examination of the emulsions formed in the process of the present invention indicate they are often of the water-in-oil type and are frequently of a tertiary character i.e. they ore oil-in-water-in-oil type.

In the case where the polyisocyanate and polyol or tar or pitch have not been reacted before emulsification it is frequently preferred to prepare the emulsion in two stages e.g. it is particularly preferred if the silicate solution and polyol or tar or pitch ·.· ' r.u are emulsified in a first stage and the polyisocyanate added at a second stage. The absence of mutually reactive chemicals in the first stage emulsion allows it to be stored or prepared in bulk if desired.

Du.271i3 If carried out in the reverse order i.e. emulsifying silicate solution and polyisocyaaate first, it is aecessary to ensure that the polyol or tar or pitch is added before the water/isocyanate reaction has proceeded to an unduly large extent whereby insufficient NCO groups are left to react with the polyol or tar or pitch.

When added at the second stage of the two stage process the polyisocyanate may not, initially at least, be soluble in the polyol or tar or pitch. Naturally the polyisocyanate is not soluble in. the silicate solution hence a multiphase emulsion is formed. This commonly takes the form of a continuous phase · consisting of the polyol or tar or pitch having two dispersed phases namely, silicate solution and polyisocyanate. . The usual course of events in such cases is that reaction of polyisocyanate with polyol or tar or pitch takes place at their interface, the products of this reaction enhancing the mutual solubility of the remaining polyisocyanate and polyol or tar or pitch resulting in their forming a homogeneous phase. The water in the silicate V__sol'ution then reacts at its interface with this single phase containing polyol or tar or pitch and polyisocyanate and their reaction products.

The reaction products of polyols or tars or pitches with excess polyisocyanate which may be used in the process of the present invention may be prepared by conventional means. Such reaction products are well known in the polyurethane art under the name of prepolymers. The known techniques for preventing premature gelation e.g. the addition of acidic materials and the selection of proportions of branched reactants are applicable to the present invention. u. * The reaction of the polyisocyanate and water in the silicate solution, results .in the formation of carbon dioxide which in turn interacts with the silicate forming silica.

To ensure the formation of solid, unfoamed compositions, sufficient alkali metal silicate must be present to react fwith most, preferably all, the carbon dioxide liberated and in practice it is usually desirable to have excess alkali metal silicate.

The amount and concentration of silicate solution i-i^icn used should be such as to ensure sufficient water is present to react with all isocyanate groups not utilised in reaction with polyol or tar or pitch. It is usually desirable to have an excess of water but this can be provided by relatively small weight proportions of water because of the low equivalent weight of water in reaction with isocyanates. The water and silicate should >-,· ^u u be present in sufficient amounts to at least satisfy the equation: ItNCO + 3H20 + Me.20. Si02 — 2( H)2C0 + 2MeHC0j + xSi02 The formation of the solid unfoamed copolymer compositions containing silica by the process of the present invention will often take place at room temperature after the emulsification of the components but heating may be used to speed the reaction.

The compositions formed by the process of the present invention may be in the form of moulded items e.g. by pouring the emulsified components whilst still fluid into a mould where it cures optionally under pressure. They may be used as binders in fibrous composite by for example impregnating mats of woven or unwoven fibres with the emulsified components. Suitable fibres include cotton, jute, glass or carbon. Such composites may be in various forms e.g. sheets or pipes useful in building construction. The compositions of the present invention may also be used in a wide variety of coating applications e.g. they may be used to provide floor or roof coverings, pipe coatings and protective and decorative finishes on a wide range of substrates e.g. wood, metal or concrete. The more flexible compositions are useful as sealants e.g. of joints in buildings. The coatings may be applied by any known method e.g. brushing or spraying.

The new process offers advantages over the usual way of incorporating silica filler into polymer compositions based on organic polyisocyanate condensation products in that (a) the silica filler is produced in colloidal form 'in situ*.

This removes any mechanical mixing and pumping problems often associated with adding silicaceous fillers directly to the polymer precursor (e.g. thixotropy, settling etc.) (b) in solid filled polyurethane polymers, the added filler must be thoroughly dried to avoid 'gassing', due to CO^ generation. The new process completely removes this problem.

The invention is illustrated but not limited by the following Examples in which parts and percentages are by weight.

Du.271i3 Example 1 ' ' 100 parts of the resin obtained as described below and 100 parts of 5^ aqueous sodium silicate are stirred together when an emulsion is formed. To this emulsion there are added 100 parts of a "crude11 diphenylmethane diisocyanate having a NCO value of 50.0 , and the mixture is stirred to give an emulsion. It sets to give a hard, unfoamed solid in k hours.

The resin used in this Example can be obtained as follows: Natural rosin (colophony), glycerol and a resol resin (obtained by the condensation of 1 mole of dip enylolpropane with approximately k moles of formaldehyde under aqueous alkaline conditions) in the proportions 8.2:1.1:1.0 by weight are heated together at a temperature of about 275°C in an inert atmosphere until the acid value of the product is less than 20 mg KOH/g. '. k parts of castor oil and 1 part of this product are then heated together at about 2^0°C for minutes.

Example 2 The process of Example 1 is repeated except that 50 g of a 1/3" granulated car tyre tread rubber is added prior to the addition of the polyisocyanate.

A hard slightly flexible compound is produced. \ Example 3 JO parts of the product of reaction of oxypropylated ethylene glycol of MW 1000 and the polyisocyanate used in Example 1 at a NCO:OH ratio of 10:1, 0 parts of 656 aqueous sodium silicate and 20 parts of coal tar (viscosity ~ 25 poise at 25°C) were blended together J to give an emulsion. The mixture has a working life of about 10 minutes and sets to a tough, slightly flexible, unfoamed solid in * hours.

Example 50 parts each of a hydroxyl-ended polybutadiene polyol of mol.wt. 2650, S % aqueous sodium silicate and the polyisocyanate used in Example 1 were mixed together, poured into V x 2" x J" greased polymethyl methacrylate moulds and allowed to cure. A tough elastomeric product viae obtained on curing for 8 hours.

Example The process of Example was repeated except that the polybutadiene polyol was replaced by 50 parts of a hydroxyl-ended etyrene-butadiene polymer of MW 35 0. Λ tough elastomeric product was obtained on curing for 8 hours.

Example 6 50 parts of a hydroxyl-ended polybutadiene polyol (M.W.2650) and parts of 65% sodium silicate solution were blended together to give an emulsion. To this emulsion was added too parts Garside 21 Sand 200 parts Flintag Grade 3 200 parts Flintag Grade k and the whole stirred until homogeneous.

To this mixture was added 0 parts of the polyisocyanate used in Example 1 , and the whole stirred until uniform.

The prepared blend was poured into 3" x 5" x 3" greased mild steel moulds and allowed to cure for 7 days, when the Compression strength of each test cube was measured. u.2711*3 Under compression the cubes behaved elastically, and had ~" an ultimate compression strength of 2200 p.s.i.

Example 7 50 parts of the reaction product of oxypropylated ethylene glycol and polyisocyanate used in Example 3» 10 parts of butyl benzyl phthalate and 1 part of "Silcolapse 1+30" (a polymethylsiloxane flow agent) are mixed together and l+O parts of a ifO¾ solution of sodium silicate added whilst subjecting the mixture to high speed stirring. The resulting emulsion remained pourable for 5-3 minutes Sheets cast from this emulsion in "Perspex" moulds could be demoulded in 3 hours and had the following properties after 7 days at room temperature: Tensile strength 2200 p.s.i.

Elongation 1 $ Flexural strength 13^0 p.s.i.

Flexural modulus 8 x 1O^ p.s.i.

Compression strength 10,500 - 11 , 600 p.o.i.

Example 8 An emulsion prepared as in Example 7 s mixed with 5 parts of 12 mm glass fibres and moulded as described in that Example.

The resulting composite had the following properties: Tensile strength 3500 p.s.i.

Elongation 1 $ Flexural strength 6000 p.s.i.

Flexural modulus x 10^ p.s.i.

Compression strength 10,000 p.s.i. - 1 - Du.271* 3 The mouldings from this and the preceding Example will ^ not maintain combustion in the absence of an external flame or other source of heat.

Example 9 100 parts of the reaction product of poly(tetrahydrofuran) mol.wt. 2000 and pure diphenylmethane diisocyanate at an NC0: 0H ratio of $~ ·Λ (NCO value = 6.21%) are blended with 11.3 parts of a >|0% sodium silicate solution to give a creamy emulsion.

The emulsion is cured in a compression mould at 2000 p.sai./l 10°C for 3 hours to give 2 mm sheets having good elastomeric properties i.e. good tensile and tear strength and elongation in excess of 300$.

Example 0 100 parts of the reaction product of poly(tetrahydrofuran) mol.wt. 1000 and pxire diphenylmethane diieocyanate at an NC0:0H ratio of 2.5: 1 (NCO value = 7· 8 ) and 1I+.2 parts of J+0# sodium silicate solution are emulsified and cured as in Example 9 to yield a similar elastomer.

Example 11 60 parts oxypropylated glycerol of mol.wt. 3000 and 30 parts of sodium silicate powder (having the approximate composition 85% 15i¾ water) are stirred together whilst 25 parts of water are gradually added and stirring is continued until the sodium silicate dissolves. 50 parts of the crude polyisocyanate used in Example 1 are added with stirring. The resulting emulsion remains pourable for 1 minute and cures quickly to give a tough unfoamed product. u. + Example 3 ♦ 50 parts of Epikote 828 (a commercially available diphenylol propane/epichlorhydrin condensate) and 50 parts of 1*0$ sodium silicate solution are emulsified by high speed stirring. 50 parts of the crude polyisocyanate used in Example 1 are added with stirring and the resulting emulsion is poured into "Perspex" moulds, where it cures at. room temperature to a hard glass-like solid.

Example lif 0 parts of the reaction product of pure diphenylmethane diisocyanate with a l+:1 mixture of polypropylene glycol mol.wt. 1000 and oxypropylated glycerol mol.wt. 1500 at an NC0:0H ratio of 2.1+: 1 (NCO value 7. ) and 0 parts of a 1+0$ sodium silicate solution are emulsified by stirring and poured into moulds. The composition cures at room temperature to a soft elastomer (hardness 0° shore A) suitable for use as a joint sealant.

Example 50 parts of the reaction product of polypropylene glycol mol.wt. 1000 and pure diphenylmethane diisocyanate at a NC0:0H ratio of 1+:1 (NCO value = 12.6%) and 1+0 parts of 1+0 sodium silicate solution are emulsified by stirring and poured onto a polyethylene sheet where it cures at room temperature to a tough flexible film.

Example Example 7 is repeated replacing the reaction product of oxypropylated ethylene glycol and crude diphenylmethane diisocyanate by a similar product from oxypropylated glycerol mol.wt. 1000 and crude diphenylmethane diisocyanate to give a cured product having the following properties: Du.2711*3 Tensile strength 21+00 p.s.i. φ Elongation 7 Flexural strength 1+000 p.s.i. lexural modulus 2.8 x 10^ p.s.i.

Compression strength 10,000 p.s.i.

Examples 17 - 19 Emulsions similar to those in Examples 9i 10 and 11 are prepared hut in all cases increasing the amount of sodium silicate solution to 1+0 parts. The resulting emulsions are cured in a 2 mm sheet compression mould under 2000 p.s.i. at room temperature for hours. After 7 days at room temperature the moulded sheets had the following properties.

Example 7 Example 8 Example 19 Prepolymers in Example 9 10 11 Tensile strength MN/m2 10.3 1^.0 20.8 Elongation at break % 1+I+0 1+00 5 0 Modulus - 100$ I+.5 7.2 8.8 20O 5 8.8 . 10.0 30O# 6.8 10.8 12.0 Trouser Tear Strength KN/m2 10.0 17.0 20.0 Hardness °BS 0 95 95 Example 20 An emulsion similar to that in Eaample 9 s prepared but using 20 parts of sodium silicate solution in place of the 11 .3 parts used in that Example.

The emulsion is poured into a 2 mm sheet compression mould and cured under 2000 p.s.i.. for 3 hours at 110°C.

Du.2711+3 The cured sheet has the. following properties: Tensile strength 21.8 MN/m Elongation at break % 6i+0 Modulus - 100# 5 200# 6.8 00# 8.6 Trouser tear strength 19.8 KN/m2 Hardness °BS 90 Example 21 2000 parts of polypropylene glycol of mol.wt. 2000 and 522 parts of toluene diisocyanate (mixed 2, 1+- and 2, 6- in proportions 80/20) were reacted together to give a prepolymer of NCO content 6.68^. 50 parts of this prepolymer were 'blended with 20 parts of a sodium silicate solution as used in Example 7 by high speed stirring. The resulting emulsion which had a pot life of 1+0 minutes, was cast into a shallow polyethylene mould and allowed to cure at room temperature for 21+ hours.

An elastomeric solid composite having no trace of foaming was produced.

Examplei 22 50 parts of a polybutadiene polyol of OH value 1+6.6 mg KOH/g, (R-1+5HT ex Atlantic Richfield) and 30 parts of isophorone diisocyar.ate were reacted together in the presence of 0.5 part of dibutyl tin dilaurate for 1+8 hours. parts of the resulting prepolymer were added to 0 parts of a sodium silicate solution as used in Example 1 with good stirring.

Du.271if3 The resulting emulsion was cast into a mould and cured at room temperature for 2 weeks. An elastomeric solid composite having no trace of foaming was produced.

Example 23 Example 7 was repeated, but using 1*0 parts of potassium silicate grade 120 ex J.Crossfield3 Ltd. in place of the sodium silicate. The resulting emulsion was pourable for 10 minutes, and had a higher exotherm than the corresponding sodium silicate mixture of Example 7· Sheets cast from the mix could be demoulded in 1 hour, and had similar properties to the composites of Example 7.

Example 2-t 100 parts of a liquid coal tar (Orgol Tar Ko.1 ex British Steel Corporation) and 80 parts of a sodium silicate solution '·;· as used in Example 7 were mixed using high speed stirring to give a dispersion of sodium silicate solution in tar. 80 parts of a crude diisocyanate as used in Example 1 were added with stirring. After 21+ hours a hard black solid product was obtained.

Example 25 300 parts of Special Pitch No.3 (ex British Steel Corporation) and 100 parts of butyl benzyl phthalate were mixed together. 200 parts of castor oil (first pressings) were added slowly with stirring to give a black mixture which was thixotropic. 500 parts of sodium silicate solution as used in Example 7 were added with stirring to the above mixture and when thoroughly mixed 250 parts of a crude diisocyanate as used in Example 1 were added.

After 2k hours a black flexible product was obtained, useful as a roofing or flooring composition.

Claims (2)

Du.271/ UK WHAT WE CLAIM IS:

1. A process for the manufacture of solid, unfoamed urea copolymer compositions containing silica, which comprises forming an oil and water emulsion v/herein the water phase comprises an aqueous solution of alkali metal silicate and the oil phase comprises a ·' mixture of an organic polyisocyanate and an organic isocyanate-reactive polyol of molecular weight at least iOO or an isocyanate-reactive tar or pitch, in which the NCO to isocyanate reactive group ratio is greater than 1, or the reaction product of an excess of an organic polyisocyanate with such an organic isocyanate reactive polyol or tar or pitch, whereby reaction takes place between NCO groups and water at the oil/water interface and evolution of carbon dioxide is prevented by reaction with the silicate, with consequent formation of silica.

2. A process for the manufacture of solid, unfoamed urea-urethane copolymer compositions containing silica, which comprises forming an oil and water ' emulsion wherein the water phase comprises an aqueous solution of alkali metal silicate and the oil phase comprises a mixture of an organic polyisocyanate and an organic isocyanate-reactive polyol of molecular weight at least i+00, in which the NCO:OH ratio is greater than 1, or the reaction product of an excess of an organic polyisocyanate with such an organic polyol, whereby reaction takes place between NCO groups and v/ater at the oil/water interface and evolution of carbon dioxide is prevented by reaction with the silicate, with consequent formation of silica. 3» A process as claimed in claim 2 wherein the isocyanate reactive polyol is a polyester. UK ί+ ο Λ process as claimed in claim 3 wherein the polyester is polyCethylene adipate). 5 · A process as claimed in claim 3 wherein the polyester is pol (ethylene/propylene adipate). 6 . A process as claimed in claim 3 wherein the polyester is poly(tetramethylene adipate). 7 o A process as claimed in y of claims 3 to 6 in which the polyester has a molecular weight of 1 000-2000.

8. A process as claimed in claim 2 wherein the isocyanate reactive polyol is a polyether. » A process as claimed in claim 8 wherein the polyether is derived from one or more alkylene oxides having three or more carbon atoms per molecule.

10. A process as claimed in claim 9 wherein the alkylene oxide is 1 : 2-propylene oxide. 1 1 . A process as claimed in claim 9 wherein the alkylene oxide is tetrahydrofuran. 1 2 . A process as claimed in claim 10 wherein the polyether is a polypropylene polyether glycol. 1 3 · A process as claimed in claim 12 wherein the molecular weight of the polypropylene polyether glycol is i OO-2000. 1 Ι(·. A process as claimed in claim 13 wherein the molecular weight of the polypropylene polyether glycol is 1000. 15 - A process as claimed in claim 1 0 wherein the polyether is polypropylene polyether triol. 16 . A process as claimed in claim 1 5 wherein the polypropyl ether triol has a molecular weight of 1+00-3000. Du.2?1i+3 UK 17· A process as claimed in claim 11 wherein the polyether io a poly(tetrahydrofuran) diol of molecular weight 1000-2000.

18. A process as claimed in claim 2 wherein the isocyanate reactive polyol is castor oil. 19· A process as claimed in claim 2 wherein the isocyanate reactive polyol is an hydroxylated polybutadiene is ^00-^000.

20. A process as claimed in claim 1 wherein the molecular weight of the hydroxylated polybutadiene is iOO-iOOO. 21 . A process as claimed in claim 20 wherein the molecular weight of the hydroxylated polybutadiene is 2000-3000.

22. A process for the manufacture of solid, unfoamed urea copolymer compositions containing silica, which comprises forming an oil and water emulsion wherein the water phase comprises an~aqueous. solution of alkali metal' silicate and the oil phase comprises a mixture' .of οί' an organic polyisocyanate and an isocyanate-reactive tar or pitch, in which the NCO to isocyanate reactive group ratio is greater than 1 , or the reaction product of an excess of an organic polyisocyanate with such a tar or pitch, whereby reaction takes place between NCO groups and water at the oil/water interface, and evolution of carbon dioxide is prevented by reaction with the silicate, with consequent formation of silica. 23· A process as claimed in claim 22 wherein the isocyanate reactivi tar or pitch is a coal tar. 21*. A process as claimed in claim 22 wherein the isocyanate reactive tar or pitch is a coal tar pitch. 5· A process as claimed in any one of claims 22 to 1 wherein an isocyanate reactive polyol of molecular weight at least IOO is UK incorporated in the composition at any stage at which isocyanate groups are present to react with it.

26. A process as claimed in any claim wherein the alkali metal silicate is potassium silicate. 27 · A process as claimed in claim 26 wherein the potassium silicate has the formula K^.xSiO^ where x has the value 1 . I 3 to J+8. 28. A process as claimed in claim 26 wherein the potassium silicate solution contains from 2? to by weight of potassium silicate. 29· A process as claimed in any preceding claim wherein the alkali metal silicate is sodium silicate.

30. A process as claimed in claim 29 wherein the sodium silicate solution contains from 35 to 60$ of sodium silicate. 3 · A process as claimed in claim 29 or claim 30 wherein the sodium silicate has a composition of Na20:Si0,, from 1 : 1 .6 to 1 : 3·3 " 32. A process as claimed in any one of claims 29 to 32 wherein the sodium silicate solution is formed in situ from water and a soluble sodium silicate powder. 33· A process as claimed in any one of the preceding claims wherein the alkali metal silicate solution provides more water than is necessary to react with all isocyanate groups not otherwise reacted and at least sufficient sodium silicate to react with all the carbon dioxide generated in the process. i . A process as claimed in any one . of the preceding claims wherein the organic polyisocyanate is crude MDI. 35· A process as claimed in any one of claims 1 -33 wherein the organic polyisocyanate is essentially pure diphenylmethane diisocyanate Du.27143 UK

36. A process as claimed in claim 35 wherein the essentially pure diphenylmethane diisocyanate is the i , I '-isomer. 37· A process as claimed in any one of the preceding claims when carried out in the presence of a catalyst known to catalyse the reaction between isocyanate groups and hydroxyl groups.

38. A process as claimed in any one of the preceding claims when carried out in the presence of a particulate filler. 39· A process as claimed in any one of the preceding claims when carried out in the presence of a fibrous filler. IfO. A process as claimed in claim 39 when the fibrous filler is in the form of a woven or unwoven mat. as i 1. A process as claimed in claim 1 substantially hereinbefore described with reference to any one of the Examples. I 2. A silica containing polyisocyanate derived composition whenever produced by a process as claimed in any one of the preceding claims. S.HOROWITZ ¾ CO. AGENTS FOR APPLICANTS BTS/RJM/BH .12.6.75.