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Description  |
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BACKGROUND OF THE INVENTION
This invention relates to a process for the production of polyisocyanate
silicate solid or cellular solid products by reacting a polyol silicate
resinous product with a polyisocyanate to produce a polyisocyanate
silicate prepolymer, then by reacting the prepolymer with a curing agent
to produce a polyisocyanate silicate solid or cellular solid product. The
polyol silicate resinous product is produced by reacting a silicon halide
with a polyol to produce the polyol silicate resinous product.
The silicon halide may be first reacted with a fine granular silicon acid,
such as hydrated silica, to produce halosilicon acids which are then
reacted chemically with polyols to produce polyol silicon acid resinous
product. The hydrated silica used in this process may be produced by any
of the commonly known methods in the arts. Natural silicates which contain
free silicic acid groups may also be used. Hydrated silica containing Si-H
groups (silicoformic acid) may also be used in this invention. It is
preferred that the hydrated silica be in a fine granular form.
The silicon halides which may be employed are those which have the
structural formula:
R.sub.y SiX.sub.z
wherein X is any halogen or mixture thereof, with the preferred being
chlorine; wherein R is independently selected from the group consisting of
a monovalent hydrocarbon radical, a monovalent alkoxy radical, and a
monovalent aryloxy radical; wherein y is an integer from 0-2, inclusive;
wherein z is an integer and the sum of y plus z is equal to 4. Each of the
R radicals should, preferably, although not essentially, contain less than
seven carbon atoms since the compounds containing these radicals are more
readily available and have been found to be the most useful. The R
radicals may be the same or different. Illustrative hydrocarbon, alkoxy
and aryloxy are as follows: alkyl radicals, such as methyl, ethyl, propyl,
isopropyl, butyl, hexyl, octyl, decyl, dodecyl, etc.; alkenyl radicals,
such as ethenyl, propenyl, etc.; alkynyl radicals such as ethynyl,
propynyl, etc.; cycloalkyl radicals, such as cyclopropyl, cyclobutyl,
cycloamyl, cyclohexyl, etc.; cycloalkenyl radicals, such as cyclobutenyl,
cyclopentenyl, cyclohexenyl, etc.; aryl radicals, such as phenyl,
anthracyl, naphthyl, etc.; aralkyl radicals, such as benzyl, phenyl-ethyl,
phenyl-propyl, etc.; alkaryl radicals, such as xylyl, tolyl, ethylphenyl,
p-butylphenyl, p-diisobutyl phenyl, etc.; alkoxy radicals, such as
methoxy, ethoxy, propoxy, etc.; and aryloxy radicals such as phenoxy,
p-butylphenoxy, etc. In addition, the hydrocarbon, alkoxy or aryloxy group
may be substituted with non-interfering substituents, such as halo (i.e.,
chloro, bromo, fluoro or iodo), nitro, sulfo, etc. The X substituent in
the silicon halide is any halogen or mixture thereof, with the preference
being chloride. Silicon trihalides may be used in certain cases.
Exemplificative silicon halides include, but are not limited to, the
following compounds: silicon tetrachloride; silicon tetrabromide; silicon
tetrafluoride; silicon tetraiodide; methyltrichlorosilane;
dimethyldichlorosilane; diethyldichlorosilane; di-n-butyl-dichlorosilane;
diphenyldichlorosilane; phenyltrichlorosilane; ethyl phenyldichlorosilane;
methyl ethyldichlorosilane; methyl propyldichlorosilane; etc.
Silicon tetrachloride is the preferred silicon halide. The silicon
tetrachloride may be utilized with any of the listed silicon halides or
mixtures of the listed silicon halides.
For the purpose of this invention, the products produced by the chemical
reaction of hydrated silica with a silicon tetrahalide will be called
halosilicon acid; the products produced by the chemical reaction of
hydrated silica with an organic halosilane will be called an organic
halosilicon acid. The product produced by reaction of the halosilicon acid
with a polyol will be called a polyol silicon acid. The product produced
by the reaction of the polyol silicon acid with a polyisocyanate will be
known as polyisocyanate silicate solid or cellular solid product. The
product produced by the reaction of a silicon halide with a polyol will be
known as a polyol silicate resinous product. The product produced by the
reaction of a polyol silicate resinous product with a polyisocyanate will
be known as a polyisocyanate silicate solid or cellular solid product.
Any suitable polyol may be used in this invention. It is preferred to use
polyols, in particular, polyol compounds and/or polyol polymers which
contain 2 to 8 hydroxyl groups, e.g. polyhydroxyl compounds and
polyesters, polyethers, polythioesters, polyacetals, polycarbonates or
polyester amides containing at least 2, generally from 2 to 8, but
preferably from 2 to 4 hydroxyl groups. Polyhydroxyl compounds (polyols)
which already contain urethane or urea groups, modified or unmodified
natural, e.g. castor oil, carbohydrates and starches, may also be used.
Additional products of alkylene oxides with phenolformaldehyde resins or
urea-formaldehyde resins are also suitable for the purpose of the
invention. Polybutadiene polymers with free hydroxyl groups, polysulfide
polymers, polybutadiene-styrene copolymers and butadiene-acrylonitrile
copolymer chains are also suitable for the purpose of the invention.
The hydroxyl group-containing polyesters (polyols) may be, for example,
reaction products of polyhydric alcohol, preferably dihydric alcohols and
polybasic, preferably dibasic carboxylic acids. The corresponding
polycarboxylic acid anhydride or corresponding polycarboxylic acid esters
of lower alcohols or their mixture may be used instead of the free
polycarboxylic acids for preparing the polyesters. The polycarboxylic acid
may be aliphatic, cycloaliphatic, aromatic, and/or heterocyclic and may be
substituted, e.g. with halogen atoms and may be unsaturated. Examples
include succinic acid, adipic acid, suberic acid, azelaic acid, sebacic
acid, phthalic acid, isophthalic acid, trimellitic acid, phthalic acid
anhydride, tetrahydrophthalic acid anhydride, hexahydrophthalic acid
anhydride, tetrachlorophthalic acid anhydride, glutaric acid anhydride,
maleic acid, maleic acid anhydride, fumaric acid, dimeric and trimeric
fatty acids such as oleic acid, optionally mixed with monomeric fatty
acids, dimethylterephthalate and bis-glycol terephthalate.
Suitable polyhydric alcohols may be used such as, for example, ethylene
glycol, propylene-1,2- and -1,3-glycol, butylene -1,4- and -2,3-glycol,
hexane-1,6-diol, octane-1,8-diol, neopentyl glycol,
cyclohexanedimethol-(1,4-bis-hydroxy-methylcyclohexane),
2-methyl-propane-1,3-diol, glycerol, trimethylol propane,
hexane-1,2,6-triol, butane-1,2,4-triol, trimethylol ethane,
pentaerythritol, quinitol, mannitol, sorbitol, glucose, starches,
fructose, cane sugar, dextrines, castor oils, methylglyoside, diethylene
glycol, triethylene glycol, tetraethyleneglycol, polyethylene glycols,
dipropene glycol, polypropylene glycols, dibutylene glycol and
polybutylene glycols. The polyesters may also contain a proportion of
carboxyl end groups. Polyesters of lactones, such as
.epsilon.-caprolactone, or hydroxycarboxylic acid, such as
.omega.-hydroxy-caproic acid, may also be used.
The polyethers with at least 2, generally from 2 to 8 and preferably 2 or 3
hydroxy groups, used according to the invention, are known and may be
prepared, e.g. by the polymerization of epoxides, e.g. ethylene oxide,
propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide, or
epichlorohydrin, each with itself, e.g. in the presence of BF.sub.3, or by
addition of these epoxides, optionally as mixtures or successively, to
starting components which contain reactive hydrogen atoms such as alcohols
or amines, e.g. water, ethylene glycol, propylene-1,3'- or -1,2-glycol,
trimethylol propane, 4,4'-dihydroxydiphenylpropane, aniline, ammonia,
ethanolamine or ethylenediamine. Sucrose polyethers such as those
described, e.g. in German Pat. Nos. 1,176,358 and 1,064,938 may also be
used according to this invention. It is frequently preferred to use
polyethers which contain primary OH groups, (up to 90% by weight, based on
the total OH group content of the polyester). Polyethers modified with
vinyl polymers such as those which may be obtained by polymerizating
styrene or acrylonitrile in the presence of polyethers (U.S. Pat. Nos.
3,383,351; 3,304,273; 3,525,093 and 3,110,695 and German Pat. No.
1,152,536) and polybutadienes which contain OH groups are also suitable.
By "polythioethers" are meant, in particular, the condensation products of
thiodiglycol with itself and/or with other glycols, dicarboxylic acids,
formaldehyde, aminocarboxylic acids or amino alcohols. The products
obtained are polythio-mixed ethers, polythioether esters or polythioether
ester amides, depending on the cocomponent.
The polyacetals used may be, for example, the compounds which may be
obtained from glycols, e.g. diethylene glycol, triethylene glycol,
(4,4'-dihydroxydiphenyldimethylmethane) hexanediol and formaldehyde.
Polyacetals suitable for the invention may also be prepared by the
polymerization of cyclic acetals.
The polycarbonates with hydroxyl groups used may be of the known kind, e.g.
those which may be prepared by reacting diols, e.g. propane-1,3-diol,
butane-1,4-diol and/or hexane-1,6-diol or diethylene glycol, triethylene
glycol or tetraethylene glycol, with diarylcarbonates, e.g.
diphenylcarbonate or phosgene.
The polyester amides and polyamides include, e.g. the predominantly linear
condensates obtained from polyvalent saturated or unsaturated carboxylic
acids or their anhydrides and polyvalent saturated and unsaturated amino
alcohols, diamines, polyamines and mixtures thereof.
Examples of these compounds which are to be used according to the invention
have been described, e.g. in "High Polymers", Vol. XVI, "Polyurethanes,
Chemistry and Technology", published by Saunders-Frisch, Interscience
Publishers, New York, London, Vol. I, 1962, pages 32 to 42 and pages 44 to
54 and Vol. II, 1964, pages 5 to 6 and 198 to 199, and in
Kunststoff-Handbuch, Vol. VII, Vieweg-Hochtlen, Carl-Hanser-Verlag,
Munich, 1966, e.g. on pages 45 to 71.
Any suitable polyisocyanate or polyisothiocyanate may be used in this
invention. For example, arylene polyisocyanates, such as tolylene,
metaphenylene, 4-chlorophenylene-1,3-, methylene-bis (phenylene-4-),
biphenylene-4,4'-, 3,3'-dimethoxybiphenylene -4,4'-,
3,3'-diphenylbiphenylene-4,4'-, naphthalene-1,5-, and
tetrahydro-naphthalene-1,5-diisocyanates and triphenylmethane
triisocyanate, alkylene polyisocyanates such as ethylene, ethylidine,
propylene-1,2-, butylene-1,4-, butylene-1,3-, hexylene-1,6-,
decamethylene-1,10-, cyclohexylene-1,2-, cyclohexylene-1,4-, and
methylene-bis (cyclohexyl-4,4'-) diisocyanates.
Any suitable polyisocyanate or polyisothiocyanate may be used in this
invention. For example, arylene polyisocyanates, such as tolylene,
metaphenylene, 4-chlorophenylene-1,3-, methylene-bis (phenylene-4-),
biphenylene-4,4'-, 3,3'-dimethoxybiphenylene -4,4'-,
3,3'-diphenylbiphenylene-4,4'-, naphthalene-1,5-, and
tetrahydro-naphthalene-1,5-diisocyanates and triphenylmethane
triisocyanate, alkylene polyisocyanates such as ethylene, ethylidine,
propylene-1,2-, butylene-1,4-, butylene-1,3-, hexylene-1,6-,
decamethylene-1,10-, cyclohexylene-1,2-, cyclohexylene-1,4-, and
methylene-bis (cyclohexyl-4,4'-) diisocyanates. Phosgenation products of
aniline-formaldehyde condensation may be used such as
polyphenyl-polymethylene polyisocyanates. Polyisothiocyanates, inorganic
polyisothiocyanates, polyisocyanates which contain carbodiimide groups as
described in German Pat. No. 1,092,007 and polyisocyanates which contain
urethane groups, allophanate groups, isocyanurate groups, urea groups,
imide groups or biuret groups may be used to produce polyisocyanate
prepolymers or polyisocyanate organic silicate solid or cellular solid
products. Mixtures of the above mentioned polyisocyanates may be used.
It is generally preferred to use commercial, readily available
polyisocyanates such as toluene-2,4- and -2,6-diisocyanate and any mixture
of these isomers, ("TDI"), ("crude MDI"),
polyphenyl-polymethylene-isocyanates obtained by aniline-formaldehyde
condensation followed by phosgenation, and modified polyisocyanates which
contain carbondiimide groups, urethane groups, allophanate groups,
isocyanurate groups, urea groups, imide groups or biuret groups,
("modified polyisocyanates").
Other polyisocyanates may be used in this invention such as polyisocyanates
which contain ester groups such as listed in British Pat. Nos. 956,474 and
1,086,404 and in U.S. Pat. Nos. 3,281,378 and 3,567,763, polyisocyanate
reaction products with acetals according to German Pat. No. 1,072,385,
polyisocyanates prepared by telomerization reactions as described in
Belgian Pat. No. 723,640, polyphenyl-polymethylene polyisocyanates as
described in British Patent specification Nos. 874,430 and 848,671,
polyisocyanates which contain carbodiimide groups as described in German
Pat. No. 1,092,007, perchlorinated arylpolyisocyanates such as those
described, e.g. in German Pat. No. 1,157,601, polyisocyanates which
contain allophanate groups as described, e.g. in British Pat. No. 994,890
and in Belgian Pat. No. 761,628, and the diisocyanates described in U.S.
Pat. No. 3,492,330, polyisocyanates which contain biuret groups as
described, e.g. in German Pat. No. 1,101,394, in British Pat. No. 889,050
and in French Pat. No. 7,017,514, polyisocyanates which contain
isocyanurate groups as described, e.g. in German Pat. Nos. 1,022,789 and
1,027,394 and in British Pat. Nos. 1,091,944, 1,267,011 and 1,305,036,
polyisocyanates which contain acylated urea groups according to U.S. Pat.
No. 3,517,139 and polyisocyanates which contain urethane groups as
described in Belgian Pat. No. 752,261 or in U.S. Pat. No. 3,394,164.
Mixtures of the above polyisocyanates may be used. Organic polyisocyanates
which are modified with ionic groups, for example, with carboxyl and/or
carboxylate groups and/or sulphonate groups may be used with the
polyisocyanates in this invention. Polyisocyanates may be reacted with
alkali metal silicates such as sodium metasilicate pentahydrate, potassium
metasilicate pentahydrate, dry granular crude sodium silicate and dry
granular lithium silicate to produce alkali metal polyisocyanate silicate
prepolymers with terminal isocyanate, used in this invention. Any of the
suitable non-ionic hydrophilically modified organic polyisocyanates may be
used in this invention.
Suitable polyisocyanates such as the aromatic diisocyanates may be reacted
with organic compounds which contain at least two hydrogen atoms capable
of reacting with isocyanates, preferably with a molecular weight of
generally from 300 to about 10,000 and in the ratio of 50 to 99 mols of
aromatic diisocyanate with 1 to 50 mols of said organic compounds to
produce isocyanate-terminated reaction products. It is preferred to use
polyols, in particular compounds and/or polymers wich contain 2 to 8
hydroxyl groups, especially those with a molecular weight of from about
800 to about 10,000 and preferably from 1,000 to about 6,000, e.g.
polyesters, polyethers, polythioethers, polyacetals, polycarbonates, or
polyester amides containing at least 2, generally from 2 to 8, but
preferably from 2 to 4 hydroxyl groups, of the kind known for producing
homogenous and cellular polyurethanes. The polyols were previously listed
in this Specification.
Any suitable curing agent and/or activator may be used in this invention.
The following are examples of curing agents, but are not limited to these:
1. Water.
2. Water containing 10% to 70% by weight of an alkali metal silicate, such
as sodium and/or potassium silicate. Crude commercial alkali metal
silicate may contain other substances, e.g. calcium silicate, magnesium
silicate, borates or aluminates and may also be used.
3. Water containing 20 to 50% of ammonium silicate.
4. Water containing 5 to 40% by weight of magnesium oxide in the form of a
colloidal dispersion.
5. Alkali metal metasilicate pentahydrate such as sodium silicate,
potassium silicate, and commercial dry granular sodium and potassium
silicate.
6. Water containing 20 to 70% by weight of silica gel.
7. Water containing 0.001 to 10% by weight of an activator (catalyst) such
as:
A. tertiary amines, e.g. triethylamine, tributylamine, N-methyl-morpholine,
N-ethyl-morpholine, N-coco-morpholine, N,N,N'N'-tetramethylene-diamine,
1,4-diazo-bicyclo(2,2,2)-octane, N-methyl-N'-dimethylaminoethyl
piperazine, N,N-dimethylbenzylamine, bis(N,N-diethylaminoethyl-adipate),
N,N-diethylbenzylamine, pentamethyldiethylenetriamine,
N,N-dimethylcyclohexylamine, N,N,N',N'-tetramethyl-1,3-bis-tanediamine,
N,N-dimethyl-beta-phenylethylamine, and 1,2-dimethylimidazole. Suitable
tertiary amine activators which contain hydrogen atoms which are reactive
with isocyanate groups include, e.g. triethanolamine, triisopanolamine,
N,N-dimethylethanolamine, N-methyldiethanolamine, N-ethyl-diethanolamine
and their reaction products with alkylene oxides, e.g. propylene oxide
and/or ethylene oxide.
B. organo-metallic compounds, preferably organo-tin compounds such as tin
salts of carboxylic acid, e.g. tin acetate, tin octoate, tin ethyl hexoate
and tin laurate and the dialkyl tin salts of carboxylic acids, e.g.
dibutyl tin diacetate, dibutyl tin dilaurate, dibutyl tin maleate or
dioctyl tin diacetate.
C. silaamines with carbon-silicon bonds, as described in British Pat. No.
1,090,589, may also be used as activators, e.g.
2,2,4-trimethyl-2-silamorpholine or
1,3-diethylaminomethyl-tetramethyl-disiloxane.
D. other examples of catalysts which may be used according to the invention
and details of their action are described in Kunststoff-Handbuch, Volume
VII, published by Viewig and Hochtlen, Carl-Hanser-Verlag, Munich, 1966,
e.g. on page 96 and 102.
8. Water containing 20 to 70% by weight of a water-binding agent, being
capable of absorbing water to form a solid or a gel, such as hydraulic
cement, synthetic anhydrite, gypsum or burnt lime.
9. Water containing 1 to 10% by weight of bases which contain nitrogen such
as tetraalkyl ammonium hydroxides.
10. Water containing 1 to 10% by weight of alkali metal hydroxides such as
sodium hydroxide, alkali metal phenolates such as sodium phenolate or
alkali metal alcoholates such as sodium methylate.
11. Water containing 1 to 10% by weight of sodium polysulfide.
Surface active additives, (emulsifiers and foam stabilizers) may also be
used according to the invention. Suitable emulsifiers are, e.g. the salts
of fatty acids with amines, e.g. oleic acid diethylamine or stearic acid
diethanolamine. Other surface active additives are alkali metal or
ammonium salts of sulphonic acid, e.g. dodecylbenzene sulphonic acid or
dinaphthyl methane disulphonic acid, or of fatty acids, e.g. ricinoleic
acid, or of polymeric fatty acids.
The foam stabilizers used are mainly water-soluble polyester siloxanes.
These compounds generally have a polydimethylsiloxane group attached to a
copolymer of ethylene oxide and propylene oxide. Foam stabilizers of this
kind have been described, e.g. in U.S. Pat. No. 3,629,308. These additives
are preferably used in quantities of from 0% to 20% by weight, based on
the reaction mixture.
Negative catalysts, for example, substances which are acidic in reaction,
e.g. hydrochloric acid or organic acid halides, known cell regulators,
e.g. paraffins, fatty alcohols or dimethyl polysiloxanes, pigments or
dyes, known flame retarding agents, e.g. tris-chloroethylphosphate or
ammonium phosphate and polyphosphates, stabilizers against aging and
weathering, plasticizers, fungicidal and bacteriocidal substances and
fillers, e.g. barium sulphate, kieselguhr, carbon black or whiting, may
also be used according to the invention.
Further examples of surface active additives, foam stabilizers, cell
regulators, negative catalysts, stabilizers, flame retarding substances,
plasticizers, dyes, fillers and fungicidal and bacteriocidal substances
and details about methods of using these additives and their action may be
found in Kunststoff-Handbuch, Volume VI, published by Vieweg and Hochtlen,
Carl-Hanser-Verlag, Munich 1966, e.g. on pages 103 to 113. The halogenated
paraffins and inorganic salts of phosphoric acid are the preferred fire
retardant agents.
SUMMARY OF THE INVENTION
I have discovered that polyol silicate resinous products and polyol silicon
acid resinous products will react chemically with a polyisocyanate
compound or prepolymer to produce a polyisocyanate silicate prepolymer and
that the prepolymer will react with a curing agent to produce a
polyisocyanate silicate solid or cellular solid product.
The preferred method to produce polyisocyanate silicate solid or cellular
solid is to react 1 mol of a silicon halide with 1 to 4 mols of a polyol
by slowly mixing while agitating to produce a polyol silicate resinous
product. The polyol silicate resinous product should contain 2 or more
free hydroxyl groups per mol. The polyol silicate resinous product is then
mixed with a polyisocyanate in the amount so that an excess of
polyisocyanate is used to produce isocyanate-terminated polyisocyanate
silicate prepolymer; the mixture is agitated for 10 to 60 minutes at
ambient temperature and pressure, thereby producing an
isocyanate-terminated polyisocyanate silicate prepolymer. The prepolymer
may be cured by heating at a temperature of 60.degree. to 160.degree. C.
for 20 to 120 minutes or by mixing with a curing agent in the amount of
3% to 200% by weight, based on the prepolymer, at a temperature of
20.degree. to 60.degree. C. and ambient pressure; the reaction is
completed in a few seconds to about 12 hours, thereby producing
polyisocyanate silicate solid or cellular solid product. The preferred
method may be altered to where the silicon halide, polyol and
polyisocyanate are mixed simultaneously while agitating at ambient
temperature and pressure for 10 to 60 minutes, thereby producing an
isocyanate-terminated polyisocyanate silicate prepolymer.
An alternate method to produce polyisocyanate silicate solid or cellular
solid products is to react 1 part by weight of a dry, fine, granular
hydrated silica with about 1 to 2 parts by weight of a silicon halide,
preferably silicon tetrachloride, to produce a white granular solid,
halosilicon acid. The halosilicon acid is then mixed with a polyol in the
ratio of 4 to 8 OH groups in the polyol to 1 to 3 halogen groups in the
halosilicon acid. There should be at least 2 free OH groups per molecule;
it is preferred that the polyol silicon acid resinous product contains 2
to 8 hydroxyl groups per molecule. The polyisocyanate will also react
chemically with the free silicic acid groups present in the polyol silicon
acid resinous product. The methods to produce halosilicon acids and polyol
silicon acid resinous product may be found in U.S. Pat. Application No.
845,464, filed Oct. 25, 1977, by David H. Blount now U.S. Pat. No.
4,120,937. The polyol silicon acid resinous product is mixed with a
polyisocyanate in the ratio of 1 to 50 mols of the polyol silicon acid
resinous product to 50 to 99 mols of the polyisocyanate or in the amount
of 0.5 to 2 parts by weight of the polyol to 1 to 10 parts by weight of
the polyisocyanate and then is agitated for 10 to 60 minutes, thereby
producing an isocyanate-terminated polyisocyanate silicate prepolymer. A
curing agent in the amount of 3% to 200% by weight, based on the weight of
the polyisocyanate silicate prepolymer, is added to the
isocyanate-terminated polyisocyanate silicate prepolymer while agitating
until the mixture begins to expand or solidify, thereby producing
polyisocyanate silicate solid or cellular solid product.
In alternate methods, a polyol may be reacted with the polyisocyanate to
produce an isocyanate-terminated polyurethane prepolymer, then reacted
with the polyol silicon acid resinous product and/or polyol silicate
resinous product, or the polyol may be added with the polyol silicon acid
resinous product, then reacted with the polyisocyanate to produce an
isocyanate-terminated polyisocyanate silicate prepolymer.
In another alternate method, the polyol silicate resinous product and/or
polyol silicon acid resinous product, the polyisocyanate and the curing
agent are mixed simultaneously to produce a polyisocyanate silicate solid
or cellular solid product.
In still another alternate method, the silicon halide, silicon acid, polyol
and the polyisocyanate may be added simultaneously to produce an
isocyanate-terminated polyisocyanate silicate prepolymer. The prepolymer
is then cured by the addition of a curing agent and/or heat to produce a
polyisocyanate silicate solid or celluloar solid resinous product.
The reactions of this invention may take place at any suitable temperature
or pressure. Although most reactions will take place at ambient
temperature and pressure, in certain reactions, a lower or elevated
temperature and elevated pressure may be necessary.
Mixtures which contain more than 30% by weight of water are usually soft
solid products which may be used as putties, surface coatings, adhesive
bonds, grouting compositions, and may be used for producing foams by
adding a blowing agent. The blowing agents are usually inert liquids with
boiling points ranging from -25.degree. to 80.degree. C.
The organic blowing agents used may be, e.g. acetone, ethyl acetate,
methanol, ethanol, halogenated alkanes, e.g. methylene chloride,
chloroform ethylidene chloride, vinylidene chloride,
monofluorotrichloromethane, dichlorodifluoromethane, butane, hexane,
heptane or diethylether. Compounds which decompose at temperatures above
room temperature with liberation of gases, e.g. nitrogen, such as azo
compounds, azoisobutyric acid nitrile, may also act as blowing agents.
Other examples of blowing agents and details about the use of blowing
agents are described in Kunststoff-Handbuch, Volume VII, published by
Vieweg and Hochtlen, Carl-Hanser-Verlag, Munich 1966, e.g. on pages 108
and 109, 453 to 455 and 507 to 510. Compressed air may be used as the
blowing agent.
The proportions of the components may be adjusted to obtain the desired
product from a solid to a highly cellular solid. When water is used, it
reacts with the NCO group to produce CO.sub.2 and pores are produced in
the product by the evolved CO.sub.2. In certain cases the CO.sub.2 is
rapidly evolved and escapes before the product hardens, and a solid
product can be produced nearly completely free of air cells. The hardening
times generally increases with additives. When a high silicate content,
from 80% to 99% by weight, is desirable, such as when the final product is
required to have mainly the properties of an inorganic silicate plastic,
in particular high temperature resistance and complete flame resistance,
an alkali metal silicate is added to the curing agent. The function of the
polyisocyanate in this case is that of a non-volatile hardener whose
reaction product is a high molecular weight polymer which reduces the
brittleness of the product.
When an alkali silicate or an alkali curing agent is used in the invention,
fine metal powder, e.g. powdered calcium, magnesium, aluminum or zinc, may
also act as blowing agents by bringing about the evolution of hydrogen.
These metal powders also have a hardening and reinforcing effect.
Various resin extenders in the amount of 0% to 50% by weight, based on the
weight of the polyisocyanate silicate prepolymer, may be added to the
polyisocyanate silicate prepolymer, such as mineral oil, coal tar,
poly-alpha-methylstyrene, and mixtures thereof.
Various plasterizers in the amount of 0% to 50%, based on the weight of the
polyisocyanate silicate prepolymer, may be added to the polyisocyanate
silicate prepolymer such as benzoate ester or phthalate ester or polyester
benzoate, e.g. dipropylene glycol benzoate, dodecyl phthalate or propylene
glycol phthalate.
The properties of the foams (cellular solid) obtained from any given
formulation, e.g. their density in the moist state, depends to some extent
on the details of the mixing process, e.g. the form and speed of the
stirrer and the form of the mixing chamber, and also the selected
temperature at which foaming is started. The foams will usually expand 3
to 12 times their original volume.
The products produced by the invention have many uses. The reaction
mixtures, with or without a blowing agent, may be mixed in a mixing
apparatus; then the reaction mixture (polyisocyanate silicate prepolymer
plus a curing agent) may be sprayed by means of compressed air or by the
airless spraying process onto surfaces; subsequently, the mixture expands
and hardens in the form of a cellular solid which is useful for
insulation, filling, and moisture-proofing coating. The foaming material
may also be forced, poured or injected molded into cold or heated molds
which may be relief molds or solid or hollow molds, optionally by
centrifugal casting and left to harden at room temperature or temperature
up to 200.degree. C., optionally under pressure. In certain cases it may
be necessary to heat the mixing or spraying apparatus to initiate foaming;
then, once foaming has started, the heat evolves by the reaction between
components which continues the foaming until the reaction is complete. A
temperature between 40.degree. to 150.degree. C. may be required to
initiate foaming. Reinforcing elements may quite easily be incorporated
into the reaction mixtures.
The inorganic and/or organic reinforcing elements may be, e.g. fibers,
metal wires, foams, fabrics, fleeces or skeletons. The reinforcing
elements may be mixed with the reaction mixture, for example, by the
fibrous web impregnation or by processes in which the reaction mixtures
and reinforcing fibers are together applied to the molds, for example, by
means of a spray apparatus. The shaped products obtained in this way may
be used as building elements, e.g. in the form of sandwich elements, e.g.
in the form of sandwich elements either as such or after they have been
laminated with metal, glass, plastics or concrete; if desired, these
sandwich elements may be foamed. The products may be used as hollow
bodies, e.g. as containers for goods which may be required to be kept
moist or cool, as filter materials or exchanges, as catalyst carriers or
carriers of active substances, as decorative elements, furniture
components and fillings for cavities. They may be used in the field of
model building and mold building, and the production of molds for metal
casting may also be considered.
The blowing agents may be adeed to the prepolymer or instead of blowing
agents, finely divided inorganic or organic hollow particles, e.g. hollow
expanded beads of glass, plastic and straw may be used for producing
cellular solid products. These products may be used as insulating
materials, cavity fillings, packaging materials, building materials which
have good solvent resistance and advantageous fire resistant
characteristics. They may also be used as light-weight building bricks in
the form of sandwiches, e.g. with metal covering layers for house building
and the construction of motor vehicles and aircraft.
Organic or inorganic particles which are capable of foaming up or have
already been foamed may be incorporated in the fluid foaming reaction
mixture, e.g. expanded clay, expanded glass, wood, cork, popcorn, hollow
plastic beads, e.g. beads of vinyl chloride polymers, polyethylene,
styrene polymers or foam particles of these polymers or of other polymers,
e.g. polysulphone, polyepoxide, polyurethane, urea-formaldehyde,
phenol-formaldehyde, polyimide polymers, or, alternatively, heaps of these
particles may be permeated with foaming reaction mixture to produce
insulating material which have good fire resistant characteristics.
The cellular solid products of this invention, in the aqueous or dry or
impregnated state, may be subsequently be lacquered, metallized, coated,
laminated, galvanized, vapor treated, bonded or blocked. The cellular
solid products may be sawed, drilled, planed, polished or used in other
working processes to produce shaped products. The shaped products, with or
without fillers, may be further modified in their properties by subsequent
heat treatment, oxidation processes, hot pressing, sintering processes or
surface melting or other compacting processes.
The novel cellular solid products of the invention are also suitable for
use as constructional materials due to their toughness and stiffness, yet
they are still elastic. They are resistant to tension and compression,
have a high dimensional stability to heat and high flame resistance. They
have excellent sound absorption capacity, heat insulating capacity, fire
resistance, and heat resistance which makes the | | |
