NO752274L - - Google Patents

Description

Process for the production of solid urea copolymer mixtures containing silicon dioxide.

The invention relates to new polymer products and more particularly to new polymer products which are based on organic polyisocyanate-derived products containing silicon dioxide fillers.

It has previously been proposed, in British patent no. 1186771, to produce silicon-containing materials by reacting aqueous solutions of alkali metal silicates with organic polyisocyanates, possibly in the presence of low molecular weight polyols. However, this method gives materials with relatively poor properties, i.e. they were brittle and had low strength. This drawback is described in GB-PS 1385605, where the limitation of the polyisocyanate/alkali metal silicate mixtures is, at least in part, attributed to a failure to achieve a fine dispersion of the components. GB-PS 1385605 proposes the use of prepolymer ionomers for the production of fine emulsions with aqueous alkali metal silicate solutions which then react so that materials with good strength and elasticity are obtained.

It has been found that unfoamed polymer mixtures of the above type, i.e. polymers containing polyurea units derived from the reaction of water and a polyisocyanate, and the incorporation of a silicon dioxide filler can be obtained without the need for special materials such as ionomers, by using other easily available isocyanate-reactive compounds than polyols with low molecular weight, namely relatively high molecular weight polyols©More tar or pitch associated with polyisocyanate-

and the alkali metal silicate solution. The polymer products according to the invention have good mechanical properties which can be varied over a wide range by choosing the isocyanate-reactive compound.

According to the invention, a method is provided for the production of solid, unfoamed urea-copolymer mixtures containing silicon dioxide, which comprises making a

oil and water emulsion where the water phase comprises one aqueous solution of an alkali metal silicate and the oil phase comprises a mixture of an organic polyisocyanate and an organic isocyanate-reactive polyol with a molecular weight of at least 400 or an isocyanate-reactive tar or pitch, where the NCO:isocyanate-reactive group ratio is greater than 1, or the reaction product of an excess of an organic polyisocyanate with one such organic isocyanate-reactive polyol or tar or pitch, whereby the reaction takes place between NCO groups and water at the oil/water interface and the evolution of carbon dioxide is prevented by reaction with the silicate , with subsequent formation of silicon dioxide.

In the above paragraph, the oil phase in the emulsion is defined in one alternative as a mixture of organic polyisocyanate and an organic isocyanate-reactive compound with a molecular weight of at least 400 or an isocyanate-reactive tar or pitch, and it should be noted that the term "mixture" includes both homogeneous and heterogeneous mixtures. Thus, the described emulsion can have a water phase g% a single oil phase or the oil phase can be two mutually immiscible oil phases if the organic polyisocyanate and the organic isocyanate-reactive compound are not mutually soluble. The nature of the emulsions will be described in more detail later in the description.

As organic polyisocyanates, for example, aliphatic diisocyanates can be used, for example hexamethylene diisocyanate, tetramethylene diisocyanate, 2,2,4- and 2,4,4-trimethylhexamethylene diisocyanates, aromatic diisocyanates, for example. tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3-methyldiphenylmethane-4,4'-diisocyanate, m- and p-phenylene diisocyanate, chlorophenylene-2:4-diisocyanate . , methylcyclohexylene diisocyanates and 3-isocyanate-omethyl-3,5,5-trimethylcyclohexylisocyanate. Triisocyanates which may be used include aromatic triisocyanates, for example 2:4:6-triisocyanatotoluene and triisocyanate bdiphenyl ether. One can also use uretedione dimers and. iso-cyanurate polymers of diisocyanates, for example tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate and mixtures thereof, and the biuret-polyisocyanates obtained by reacting polyisocyanates

which is obtained by reacting polyisocyanates and water.

Mixtures of polyisocyanates can be used, including those obtained by phosgenation of the blaride pblyamines produced by reaction of formaldehyde with aromatic amines, for example 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 produced by the reaction of formaldehyde with aniline in the presence of hydrochloric acid and which

consists of diphenylmethane-4,4'-diisocyanate in a mixture with isomers thereof and with methylene-linked polyphenol polyisocyanates containing more than two isocyanate groups.

It is preferred to use substantially pure diphenylmethane diisocyanate, especially the 4,4'-isomer when elastomeric products are required.

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

Any isocyanate-reactive polyol with a molecular weight of at least 400 or isocyanate-reactive tar or pitch can be used in the method according to the invention, provided that, in the form in which it is to be used, i.e. as it is 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 isocyanate-reactive compounds mentioned above should have a low solubility in water and a hydrophobic character. This requirement is often slightly less stringent when the polyol is reacted with an excess of polyisocyanate before emulsification, but in this case it is also generally preferred that it should have a hydrophobic character.

A preferred embodiment of the invention utilizes organic isocyanate-reactive polyols having a molecular weight of at least 400. Thus, in accordance with this preferred form of the invention, there is provided a process for the preparation of solid, unfoamed urea/urethane copolymer mixtures containing silica, comprising forming an oil and water emulsion, where 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 with a molecular weight of at least 400, where 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 the reaction takes place between NCO groups and water at the oil/water interface, and the development of carbon dioxide is prevented by reaction with the silicate, with subsequent formation of silicon dioxide.

The nature of the polyol determines the character of resulting copolymer blends according to relationships well known in the polyurethane art, for example, high molecular weight linear polyols typically yield elastomeric products, and lower molecular weight branched polyols yield rigid products.

As examples of polyols for use in connection with the invention, mention may be made of polyesters and polyesteramides, for example those obtained by known methods from carboxylic acids, glycols and, as necessary, smaller amounts of diamines or amino alcohols. Suitable dicarboxylic acids include succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid and terephthalic acid and mixtures thereof. Examples of dihydric alcohols include ethylene glycol, 1:2-propylene glycol, 1:3-butylene glycol, 2S3-butylene glycol, diethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol and 2:2-dimethyltrimethylene glycol. Suitable diamines or amino alcohols include hexamethylenediamine, ethylenediamine, monoethanolamine and phenylenediamines. Mixtures of polyesters and polyester amides can be used if desired. Small amounts of polyhydric alcohols, for example glycerol or trimethylolpropane, can also be used, in which case branched polyesters and polyesteramides are obtained.

Preferred polyesters for use with the method according to the invention are those having a molecular weight of 1000-2000, especially poly(ethylene adipate), poly(ethylene/propylene adipate), poly(tetramethylene adipate) and poly(ethylene/tetramethylene adipate).

As examples of polyols for use in connection with the invention, mention can also be made of polyethers, for example polymers and copolymers of cyclic oxides, for example 1:2-alkylene oxides, for example ethylene oxide, epichlorohydrin, 1s2-butylene oxide and 2t3-butyleneoxy, oxycyclobutane and substituted oxycyclobutanes and tetrahydrofuran. Mention may also be made of polyethers obtained by polymerization of an alkylene oxide in the presence of a basic catalyst and, when, such polyols as ethylene glycol, propylene glycol, glycerol, trimethylolpropane, triethanolamine or such amines as aniline, tolylenediamine, aniline/formaldehyde condensates, for example those used as precursors for pure MDI, as well as ethylenediamine. It will be understood that polyethers can be linear, i.e. polyetherdiols or branched, i.e. polyethertriols, tetrols, etc., depending on the functionality of the polyol or amine used for reaction with the alkylene oxide.

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

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

Polypropylene polyether glycols of molecular weight 400-2000 are a particularly preferred class of polyethers, and molecular weight of 1000 is particularly preferred.

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

Another particularly preferred class of polyethers

are branched polyethers from 1:2-propylene oxide. Particularly preferred are polypropylene polyether triols with molecular weights of 400-3000. Such triols are obtained from the alkaline polymerization of propylene oxide in the presence of glycerol, trimethylolpropane, triethanolamine and hexanetriols.

Another preferred polyol is castor oil.

A further class of preferred polyols are hydroxylated polybutadienes, for example the products of free radical or anionic polymerization of butadiene under such conditions that a majority of hydroxyl groups are introduced into polymer nuclei. It is particularly preferred that such products have molecular weights of 400-4000, especially 2000-3000.

Other polyols that can be used in the process

according to the invention, include epoxy resins which also contain isocyanate-reactive groups, for example the hydroxyl group-containing products obtained by reaction between diphenylolpropane and epichlorohydrin, alkyd resins modified with drying oil and non-drying oil, 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 IIa of the periodic table or a condensation product of rosin with

(I) at least one polyhydric alcohol

or (II) at least Sn polyhydric alcohol and at least one optionally substituted phenol/formaldehyde resole resin,

or (III) at least one polyhydric alcohol and at least one ot/S-unsaturated dicarboxylic acid or its anhydride.

Another preferred embodiment of the invention makes use of an isocyanate-reactive tar or pitch. Thus, according to this preferred embodiment, there is provided a method for producing solid, unfoamed urea-copolymer mixtures containing silicon dioxide, and this method comprises forming an oil and water emulsion where the water phase comprises an aqueous solution of an alkali metal silicate and the oil phase comprises a mixture of a organic polyisocyanate and an isocyanate-reactive tar or pitch, where the NCO: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 the reaction takes place between NCO groups and water at the oil/water interface,

and the development of carbon dioxide is prevented by reaction with the silicate, with subsequent formation of silicon dioxide.

Tars and pitches containing isocyanate-reactive groups which are suitable for use in the method according to the invention are defined and described in detail in GB-PS 1038009. Particularly valuable for use in the method according to

to the invention are the types of tar that result from the destructive distillation of coal, i.e. coal tar, and particularly valuable are the types of pitch that are formed when these types of tar are themselves distilled,

that is, coal tar pitch. Products from the method according to the invention, which use tar and pitch, are associated with particularly good resistance to water, putrefactive organisms and pests. They often also show advantages in terms of relatively low price.

In the above preferred embodiment which does

use of an isocyanate-reactive tar or pitch, an isocyanate-reactive polyol with a molecular weight of at least 400 may also be mixed into the mixture at any stage at which isocyanate groups are present for reaction with said polyol. For example

the polyol can be premixed with the tar or pitch. Alternatively, both the isocyanate-reactive polyol and the isocyanate-reactive tar or pitch may be added separately to the silicate solution and the polyisocyanate at any stage during the formation of the emulsion.

It may be convenient to react either the tar or the pitch or the polyol with an excess of polyisocyanate before mixing in an emulsion with silicate solution and the other component, namely the tar or the pitch or the polyol. Both can also be reacted with an excess of polyisocyanate before emulsification with a silicate solution. Where the method specifies an excess of polyisocyanate, it should be understood that this means an excess in relation to the amount needed for reaction with both the polyol and the tar or pitch.

Any of the polyols with a molecular weight of at least 400 mentioned earlier can be used in the above-mentioned method, provided that it is or during the process becomes compatible with the tar or pitch. Polyols are generally more likely to give compatible systems with the tar or pitch if first reacted with an excess of polyisocyanate.

The products produced by the method according to the invention may also contain other fillers, for example talc, kaolin, barytes, asbestos, mica, zinc stearate, slate powder, wood flour, sawdust, vermiculite, wood chips, fiberglass, fly ash from power stations, expanded clay, marble and other natural or artificially colored sand types, stone, flint or rock, inorganic pigments, for example red iron oxide, titanium dioxide and chromium pigments, organic pigments, for example azo pigments and pigments based on phthalocyanine, and synthetic organic polymers such as can be thermoplastic or thermosetting polymers or copolymers, for example nylon polymers, polyvinyl chloride, polyvinyl chloride/polyvinyl acetate copolymers, urea/formaldehyde polymers, acetate polymers and copolymers, acrylic polymers and copolymers, acrylonitrile/butadiene/styrene terpolymers, cellulose acetate, cellulose acetate butyrate, polycarbonates, polyethylene terephthalates, polystyrenes, polyurea tanners, polyethylenes and polypropylenes. These polymers can be unpigmented or mass-pigmented and can be introduced into the mixture in the form of powder, lumps, turning chips, fibres, flakes, tapes or films.

Any of the components used

for forming the emulsion by the method according to the invention, may also contain a catalyst which is known to catalyze the reaction between isocyanate groups and hydroxyl groups. Included among such catalysts are organometallic compounds, metal salts and tertiary amines, and specific examples of these are dibutyltin dilaurate, tetrabutyltitanate, zinc octoate, zinc naphthenate, stannous octoate, stannous fluoride/~férrIclo^^ potassium oleate, cobalt-2-ethylhexoate, N ,N-dimethylcyclohexylamine,

N,N-dimethylbenzylamine, N-ethylmorpholine, 1,4-diazobicyclo-2,2,2-octane, 4-dimethylamdinopyridine, oxypropylated triethanolamines, B-diethylaminoethanol and N,N,N',N'-tetrakis(2-hydroxypropyl )ethylenediamine.

The alkali metal silicates used are preferably potassium or, more preferably, sodium silicates. They can be represented by the formula Me 2 O .x SiO 2 where Me is the alkali metal and x is the SiO 2 :Me 2 O molar ratio. In the case of potassium silicate, x preferably ranges from 1.43 to 2.48, and in the case of

sodium silicate, values for x of from 1.6 to 3.3 are preferred.

The solution used can contain from 1 to 99% by weight of alkali metal silicate, preferably 35-60% for sodium, 27-52% for potassium. If desired, the alkali metal silicate solution used can be formed in situ, for example by adding a soluble alkali metal silicate powder and water to a polyol with agitation whereby the silicate dissolves in the water before, during or after it is emulsified into the polyol.

The proportion of the total weight of polyisocyanate and polyol or tar or pitch that is polyol or tar or pitch

may vary within strict limits. It will usually not be less than 25% and may be as high as 95%, for example when elastomeric products are formed from high molecular weight polyols, for example 10,000 molecular weight diols.

The mixing of the components to produce the emulsion can be carried out by methods known in the field. The degree of mixing required to produce a fine emulsion will vary with the nature of the components. In some cases, simple agitation is sufficient, but in others, high-speed, high-shear mixing may be necessary. The addition of emulsifiers, for example non-ionic types such as ethylene oxide/propylene oxide block copolymers, may be beneficial but is rarely necessary.

Microscopic examination of the emulsions formed by the method according to the invention indicates that they are often of the water-in-oil type and are frequently of a tertiary nature, that is to say that they are of the oil-in-water-in-oil type.

In the event that the polyisocyanate and the polyol or the tar or the pitch have not reacted before emulsification, it is often preferable to prepare the emulsion in two steps, for example it is particularly preferred if the silicate solution and the polyol or the tar or the pitch are emulsified in a first step and the polyisocyanate is added in another step. The absence of mutually reactive chemicals in the first stage emulsion means that it can be stored or produced in bulk if desired.

If it takes place in reverse order, that is

that one first emulsifies silicate solution and polyisocyanate, it is necessary to ensure that the polyol or tar or pitch is added before the water/isocyanate reaction has taken place to a particularly large extent, whereby insufficient NCO groups remain to react with the polyol or tar or pitch.

When added in the second step of the two-step process, the polyisocyanate cannot, initially at least, be soluble in the polyol or the tar or pitch. Naturally, the polyisocyanate is not soluble'! the silicate solution, and therefore a multiphase emulsion is formed. This usually takes the form of a continuous phase consisting of the polyol or tar or pitch with two dispersed phases, namely silicate solution and polyisocyanate. The usual process in such cases is that reaction of polyisocyanate with polyol or tar or pitch takes place at the interface,

as the products from this reaction improve the mutual solubility of the remaining polyisocyanate and polyol or tar or bbk which results in them forming a homogeneous phase. The water in the silicate solution 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 tar or pitch compounds with an excess of polyisocyanate which can be used in the method according to the invention can be prepared by conventional means. Such reaction products are well known in the polyurethane field under the name of prepolymers. The known techniques for preventing premature gelation, for example addition of acidic materials and selection of amounts of branched reactants, are applicable to the present invention.

The reaction between the polyisocyanate and the water in the silicate solution results in the formation of carbon dioxide, which in turn reacts with the silicate to form silicon dioxide. To ensure the formation of solid, non-foamed products, sufficient alkali metal silicate must be present to react with most, preferably all, of the carbon dioxide that is released, and in practice it is usually desirable to have an excess of alkali metal silicate.

The amount and concentration of silicate solution used should be such as to ensure that sufficient water is present to react with all isocyanate groups not used in reaction with polyol or tar or pitch. It is common-

it is desirable to have an excess of water, but this can be provided with relatively small parts by weight of water due to the water's

low equivalent weight in the reaction with isocyanates. The water and silicate should be present in sufficient quantities to at least satisfy the equation: 4NC0 + 3H20 + Me20.xSi022(NH)2C0 + 2MeHC03+ xS102

The formation of the solid, unfoamed copolymer products containing silicon dioxide, by the method according to the invention, will often take place at room temperature after the emulsification of the components, but heating can be used to speed up the reaction.

The products formed by the method according to the invention can be in the form of molded articles, for example by pouring the emulsified components while they are still liquid into a mold where they harden, possibly under pressure. They can be used as binders in composite fiber products, for example by impregnating mats of woven or non-woven fibers with the emulsified components. Suitable fibers include cotton, jute, glass or charcoal. Such composite products can take different forms, for example sheets or tubes which are useful in the construction industry. The products according to the invention can also be used to a large extent for coating purposes. For example, they can be used to provide floor or roof covering, pipe-line coating and protective and decorative finishes on a wide range of substrates, for example wood, metal or concrete. The more flexible products are useful as sealants, for example for joints in buildings. The coatings can be applied by any known method, for example by brush or by spraying.

The new method offers advantages compared to the usual way of incorporating silicon dioxide filler into polymer products which are based on organic polyisocyanate condensation products in that

(a) the silica filler is produced in colloidal form in situ. This removes all mechanical mixing and pumping problems often associated with direct addition of siliceous fillers

to the polymer precursor (for example, thixotropy, settling, etc.)j (b) in solid, filled polyurethane polymers, the added filler must be thoroughly dried to avoid "gassing", due to CO2 evolution.

The new procedure completely removes this problem.

The invention shall be illustrated in the following,

but not be limited, by examples where parts and percentages indicate weight.

Example 1

100 parts of the resin obtained as described below, and 100 parts of 65% aqueous sodium silicate are stirred together to form an emulsion. To this emulsion is added 100 parts of a "raw" diphenyl ether diisocyanate with an NCO value of 30.0, and the mixture is stirred so that an emulsion is obtained. It cures to a hard, non-foaming solid within 4 hours.

The resin used in this example can be obtained in the following way: Rosin, glycerol and a resole resin (obtained by condensation of one mole of diphenylolpropane with approximately 4 moles of formaldehyde under aqueous alkaline conditions) in the ratio 8.2:1.1:1.0 by weight are heated together at a temperature of approx. 275°C in an inert atmosphere until the acid number of the product is less than

20 mg KOH/g.

4 parts castor oil and 1 part of this product are then heated together at approx. 240°C for 45 minutes.

Example 2

The procedure from example 1 is repeated, with the exception that 50 g of a 3.2 mm granulated car tire thread rubber is added before the addition of the polyisocyanate.

A hard, slightly flexible connection is produced.

Example 3

30 parts of the reaction product between oxypropylated ethylene glycol with MV 1000 and the polyisocyanate used in example 1 in an NC0:0H ratio of 10:1, 50 parts of 65% aqueous sodium silicate and 20 parts of coal tar (viscosity 25 pois at 25° C) was mixed together so that an emulsion was obtained. The mixture has a processing time of approx. 10 minutes and hardens to a tough, slightly flexible, unfoamed solid within 4 hours.

Example 4

50 parts each of a hydroxyl-terminated polybutadiene polyol with MV 2650, 65% aqueous sodium silicate and the polyisocyanate used in Example 1 were mixed together, poured into 101.6 mm x 50.8 mm x 12.7 mm greased polymethyl methacrylate molds and allowed to cure. A tough, elastomeric product was obtained by curing for 8 hours.

Example 5

The procedure of Example 4 was repeated, except that the polybutadiene polyol was replaced by 50 parts of a hydroxyl-terminated styrene butadiene polymer with MV 3500.

A tough, elastomeric product was obtained by curing for 8 hours.

Example 6

50 parts of a hydroxyl-terminated polybutadiene polyol (MV 2650) and 50 parts of 65% sodium silicate solution were mixed into an emulsion. To this emulsion was added

400 parts "Garside 21" sand

200 pieces "Flintag Grade 3"

200 pieces "Flintag Grade 4"

and everything stirred until it was homogeneous.

To this mixture was added 50 parts of the polyisocyanate used in example 1, and everything was stirred until it was uniform.

The prepared mixture was poured into 76.2 mm x 76.2 mm x 76.2 mm greased mild steel molds and allowed to cure for 7 days, after which the compressive strength of each test cube was measured.

During compression, the cubes behaved elastically and had a final compressive strength of 154 kg/cm<2>.

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 "Silicolapse 430" (a polymethyl siloxane flow agent) are mixed and 40 parts of a 40% solution of sodium silicate are added while the mixture is exposed to high-speed stirring. The resulting emulsion remained pourable for 25-30 minutes. Sheets cast from this emulsion in "Perspex" molds could be removed from the mold after three hours and had the following properties after 7 days at room temperature»

Example 8

An emulsion prepared as indicated in Example 7 is mixed with 5 parts of 12 mm glass fibers and cast as described in Example 7. The resulting composite product had the following properties

The castings from this and the previous example will not sustain combustion in the absence of an external flame or other heat source.

Example 9

100 parts of the reaction product of poly(tetrahydrofuran) with MV 2000 and pure diphenylmethane diisocyanate in an NCO:OH ratio of 3:1 (NCO value = 6.21%) are mixed with 11.3 parts of a 40% sodium silicate solution so that you get a creamy emulsion.

The emulsion is hardened in a compression mold at 140 kg/cm /110 C for 3 hours so that you get a 2 mm sheet with good elastomeric properties, that is, good tensile and tear strength and elongation over 300%.

Example 10

100 parts of the reaction product of poly(tetrahydrofuran) with MV 1000 and pure diphenylmethane diisocyanate in an NCOsOH ratio of 2.5:1 (NCO value = 7.8%) and 14.2 parts of 40% sodium silicate solution are emulsified and hardened as in example 9, so that a similar elastomer is obtained.

Example 11

60 parts of oxypropylated glycerol with MV 3000 and 30 parts of sodium silicate powder (with approximate composition 85% NajSiO-j, 15% water) are stirred together while 25 parts of water are gradually added and the stirring continues until the sodium silicate dissolves. 50 parts of the crude polyisocyanate used in example 1 are added while stirring. The resulting emulsion remains pourable for 1 minute and hardens rapidly so that a tough, non-foaming product is obtained.

Example 13

50 parts of "Epicote 828" (a commercially available tiifttnyiolpropah/epichlorohydrin condensate) and 50 parts of 40% sodium silicate solution are emulsified by stirring under high speed. 50 parts of the crude polyisocyanate used in Example 1 is added with stirring, and the resulting emulsion is poured into "Perspex" moulds, where it hardens at room temperature to a hard, glassy substance.

Example 14

50 parts of the reaction product of pure diphenylmethane diisocyanate with a 4:1 mixture of polypropylene glycol (MV 1000)

and oxypropylated glycerol (MV 1500) in an NCOsOH ratio of 2.4:1 (NCO value 7.3%) and 30 parts of a 40% sodium silicate solution are emulsified by stirring and poured into moulds. The mixture hardens at room temperature to a soft elastomer (hardness 50° Shore a) which is suitable for use as a sealant for joints.

Example 15

50 parts of the reaction product of p^iy#r.opyl$trølyJcQl with MV 1000 and pure diphenylmethane diisocyanate in an NCOjOH ratio of 4:1 (NCO value - 12.6%) and 40 parts of a 40% sodium silicate solution are emulsified upon stirring and is poured onto a polyethylene sheet where it hardens at room temperature to a tough, flexible film.

Example 16

Example 7 is repeated by replacing the reaction product of oxypropylated ethylene glycol and crude diphenylmethane diisocyanate with a similar product of oxypropylated glycerol (MV 1000) and crude diphenylmethane diisocyanate so that a hardened product with the following properties is obtained:

Examples 17 - 19

Emulsions similar to those in examples 9, 10 and 11 are prepared, but in all cases the amount of sodium silicate solution is increased to 40 parts. The resulting emulsions are cured in a

2 mm sheet compression mold under 140 kg/cm<2>at room temperature for 3 hours. After 7 days at room temperature, the molded sheets had the following properties:

Example 20

An emulsion similar to that from example 9 is prepared, but using 20 parts of sodium silicate solution instead of the 11.3 parts that were used in the aforementioned example.

The emulsion is poured into a 2 mm sheet compression mold and cured at 140 kg/cm2 for 3 hours at 110°C.

The hardened sheet had the following properties:

Example 21

2000 parts of polypropylene glycol with MV 2000 and 522 parts of toluene diisocyanate (mixed 2,4- and 2,6- in the ratio 80/20) were reacted so that a prepolymer with an NCO content of 6.68% was obtained. 50 parts of this prepolymer were mixed with 20 parts of a sodium silicate solution as used in example 7 by stirring at high speed. The resulting emulsion, which had a pot life of 40 minutes, was cast into a shallow polyethylene mold and allowed to cure at room temperature for 24 hours.

An elastomeric solid composite product with no trace of foaming was produced.

Example 22

50 parts of a polybutadiene polyol with an OH number of 46.6 mg KOH/g, ("R-45HT" from Atlantic Richfield) and 30 parts of isoporone diisocyanate were reacted in the presence of 0.5 part dibutyltin dilaurate for 48 hours. 50 parts of the resulting prepolymer was added to 50 parts of a sodium silicate solution as used in Example 1, with good stirring. The resulting emulsion was cast into a mold and cured at room temperature for 2 weeks. An elastomeric, solid, composite product with no trace of foaming was obtained silenced.

Example 23.

Example 7 was repeated but using 40 parts potassium silicate grade 120 from J. Crossfields Ltd.

instead of the sodium silicate. The resulting emulsion was pourable for 10 minutes and had a higher exotherm than the corresponding sodium silicate mixture from Example 7. Sheets cast from the mixture could be removed from the mold after 1 hour and had properties similar to the composite products of Example 7.

Example 24

100 parts of a liquid coal tar ("Orgol Tar No.1" from British Steel Corporation) and 80 parts of a sodium silicate solution as used in Example 7 were mixed using high speed stirring to obtain a dispersion of sodium silicate solution in tar . 80 parts of a crude diisocyanate as used in example 1 were added with stirring. After 24 hours, a hard, black, solid product was obtained.

Example 25

300 parts of "Special Pitch No.3" (from British Steel Corporation) and 100 parts of butyl benzyl phthalate were mixed. 200 parts of castor oil (from the first pressing) were added slowly while stirring so that a black mixture was obtained which was thixotropic.

500 parts of sodium silicate solution as used in example 7 were added with stirring to the above mixture, and after thorough mixing 250 parts of a crude diisocyanate as used in example 1 were added.

After 24 hours, a black, flexible product was obtained, useful as a roof or floor covering.

Claims (1)

1. Process for the production of solid, unfoamed urea copolymer products containing silicon dioxide, characterized in that an oil and water emulsion is formed where 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 with a molecular weight of at least 400 or an isocyanate-reactive tar or pitch, where the NCO: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 the reaction takes place between NCO groups and water at the oil/water interface and the development of carbon dioxide is prevented by reaction with the silicate, with subsequent formation of silicon dioxide. 2. Method as stated in claim 1, characterized in that an oil and water emulsion is formed where 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 with a molecular weight of at least 400, where the NCOsOH ratio is greater than 1, or the reaction product of an excess of an organic polyisocyanate with such an organic polyol, whereby the reaction takes place between NCO -groups and water at the oil/water interface and the development of carbon dioxide is prevented by reaction with the silicate, with subsequent formation of silicon dioxide. 3. Method as stated in claim 2, characterized in that a polyester is used as isocyanate-reactive polyol. 4. Method as stated in claim 3, characterized in that polyethylene adipate is used as polyester. 5. Method as set forth in claim 3, characterized in that polyethylene/propylene phthalate is used as polyester 6. Method as specified in claim 3, characterized in that polytetramethylene is used as polyester adipate. 7. Method as stated in any of claims 3 to 6, characterized in that a polyester with a molecular weight of 1000-2000 is used. 8. Process as stated in claim 2, characterized in that a polyether is used as isocyanate-reactive polyol. 9. Method as stated in claim 8, characterized in that a polyether is used which is derived from one or more alkylene oxides with three or more carbon atoms per molecule. 10. Method as stated in claim 9, characterized in that 1:2-propylene oxide is used as alkylene oxide. 11. Method as stated in claim 9, characterized in that tetrahydrofuran is used as alkylene oxide. 12. Method as stated in claim 10, characterized in that a polypropylene polyether glycol is used as polyether. - 13. Method as stated in claim 12, characterized in that a polypropylene polyether glycol with a molecular weight of 400-2000 is used. 14. Method as stated in claim 13, characterized in that a polypropylene polyether glycol with a molecular weight of 1000 is used. 15. Method as stated in claim 10, characterized in that polypropylene polyether triol is used as polyether. 16. Method as stated in claim 15, characterized in that a polypropylene teretriol with a molecular weight of 400-3000 is used. 17. Method as set forth in claim 11, characterized in that a poly-(tetrahydrofuranXdiol with a molecular weight of 1000-2000) is used as polyether. 18. Method as stated in claim 2, characterized in that castor oil is used as isocyanate-reactive polyol. 19. Method as stated in claim 2, characterized in that a hydroxylated polybutadiene with a molecular weight of 400-4000 is used as isocyanate-reactive polyol. 20. Method as stated in claim 19, characterized in that a hydroxylated poly-butadiene with a molecular weight of 400-4000 is used. 21. Method as stated in claim 20, characterized in that a hydroxylated poly-butadiene with a molecular weight of 2000-3000 is used. 22. Process for the production of solid, unfoamed urea copolymer products containing silicon dioxide, characterized in that an oil and water emulsion is formed where the water phase comprises an aqueous solution of alkali metal silicate and the oil phase comprises a mixture of an organic polyisocyanate and an isocyanate-reactive tar or pitch, where the NCO: the 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 the 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 subsequent formation of silicon dioxide. 23. Method as stated in claim 22, characterized in that coal tar is used as isocyanate-reactive tar or pitch. 24. Method as stated in claim 22, characterized in that a coal tar pitch is used as isocyanate-reactive tar or pitch. 25. A method as set forth in any one of claims 22 to 24, characterized in that an isocyanate-reactive polyol of molecular weight at least 400 is mixed into the product at any stage at which the isocyanate groups are present for reaction with it. 26. Method as stated in any of the preceding claims, characterized in that potassium silicate is used as alkali metal silicate. 27. Method as stated in claim 26, characterized in that a potassium silicate of formula K2 0.xSi02 is used where x has the value 1.43 to 2.48. 28. Method as stated in claim 26, characterized in that a potassium silicate solution containing from 27 to 52% by weight of potassium silicate is used. 29. Method as stated in any of the preceding claims, characterized in that sodium silicate is used as alkali metal silicate. 30. Method as stated in claim 29, characterized in that a sodium silicate solution containing from 35 to 60% sodium silicate is used. 31. Procedure as stated in claim 29 or. 30, characterized in that a sodium silicate is used which has a composition of Na^sSiOj of from 1:1.6 to 1:3.3. 32. Method as stated in any one of claims 29 to 32, characterized in that the sodium silicate solution is formed in situ from water and a soluble sodium silicate powder. 33. A method as set forth in any one of the preceding claims, characterized in that the alkali metal silicate solution provides more water than is necessary to react with all isocyanate groups which have not otherwise reacted, and at least sufficient sodium silicate to react with all the carbon dioxide that is developed in the process. 34. Method as stated in any of the preceding claims, characterized in that raw MDI is used as organic polyisocyanate. 35. Method as stated in any of claims 1-33, characterized in that essentially pure diphenylmethane diisocyanate is used as organic polyisocyanate. 36. Process as set forth in claim 35, characterized in that the 4,4'-isomer is used as essentially pure diphenylmethane diisocyanate. 37. Method as stated in any of the preceding claims, characterized in that it is carried out in the presence of a catalyst known to catalyze the reaction between isocyanate groups and hydroxyl groups. 38o Method as stated in any of the preceding claims, characterized in that it is carried out in the presence of a particle-lined filler. 39. Method as stated in any of the preceding claims, characterized in that it is carried out in the presence of a fibrous filler. 40. Method as stated in claim 39, characterized in that it is used as a fibrous filler one which is in the form of a woven or non-woven mass.