DE2713984A1 - STORAGE MOLDING - Google Patents

Description

"".
*.! ··· ·
Bayer Aktiengesellschaft —_ -j
t
'(
· ■ ·
• ·
• *
• ·
• * ί 2713984
Central area
Patents, trademarks
and licenses Storable molding compound 5090 Leverkusen, Bayerwerk
Kb / AB
2a March 1977
ί

The present application relates to storage-stable, cold-formable low-density molding compositions that are difficult or even difficult are non-flammable and are mainly composed of inorganic material and, to a lesser extent, polyisocyanates exist as a binder and a process for the production of mold parts from these molding compounds.

It is known from various starting materials such as wood chips, waste materials, molding sand or gravel with polyisocyanates to produce moldings as a binder. However, these starting materials are very irregularly shaped Formations so that they either become a complete superficial one Coverage by the binding agent or require a relatively large amount of binding agent due to a certain pumping speed, or only partially provided with the binder. The moldings obtained thereby have one thing in them quite inhomogeneous structure, so that some homogeneity-related quality features, e.g. uniform or optimally developed Strength is lacking.

Le A 17 899

809840/0297

It is also known to use e.g. hollow glass spheres as a filler for plastics. Here they are either incorporated into the pre-formed plastics, e.g. thermoplastics, or the liquid synthetic resins, e.g. polyester resins or epoxy resins are added before curing, these synthetic resins, in order to cure through, very carefully with the necessary Hardeners, e.g. peroxides or amines, must be homogenized. Such plastics filled with hollow glass spheres mostly contain less than 50% by weight of inorganic filler.

Because of the possible shortage of organic raw materials and the risk of fire in human living and To reduce the working range, there is a need for materials that are easy to process, good mechanical and thermal Have properties and are largely composed of inorganic material. In the manufacture and processing The materials sought should also include, for example, the use of peroxides and physiologically questionable amines or relatively volatile, i.e. ecologically questionable, compounds should be avoided.

DOS 2 357 931 describes the bonding of organic or inorganic, foamed, porous or solid, uniform or irregularly shaped particles due to polyisocyanates.

This method can be used when using non-volatile Polyisocyanates, due to their curability through moisture, partially solve the above-mentioned problems however, it also leads to relatively inhomogeneous molded parts and is unsatisfactory in terms of the amount of binder required, since foamed, porous particles are either relatively large and thus produce relatively inhomogeneous molded parts,

Le A 17 899 - 2 -

809840/0297

or the porosity of the particles the absorption of the binder favored. In addition, the use of massive inorganic particles affects production more easily and thus easily manageable, material-saving and, if necessary, heat-insulating molded parts.

There is therefore a need for heat-resistant and, if necessary, temperature-resistant materials and / or moldings which can be produced using uncomplicated processes, ie from storage-stable premixes that are as deformable as possible. .ε contain volatile substances, peroxides or physiologically questionable hardeners and have mechanical properties that are as isotropic as possible at liter weights below 1000 grams, the content of organic material being below 30% by weight.

Surprisingly, these requirements can be met with mixtures meet those of more than 50 wt .-% inorganic hollow spheres with a bulk weight below 800 g / l, grain diameters less than 1 mm, which as a 50% mixture with distilled water gives a pH value of 5-7 and less than 50% by weight consist of non-volatile liquid polyisocyanates in which the hollow beads are coated with the polyisocyanate. These Mixtures are shaped, if appropriate after the addition of water and other auxiliaries, and then at room temperature and exposure to atmospheric moisture and / or heating, optionally cured under pressure to temperatures of up to 280 ° C.

Accordingly, the present process for the production of molded parts with largely isotropic properties, weights per liter less than 10OO grams and largely inorganic in character from stable, cold-deformable raw materials with safe handling, characterized in that the starting material is mixtures of

Le A 17 899 - 3 -

809840/0297

70-98% by weight of inorganic hollow spheres with a bulk density below 800 g / l and grain diameters below 1 mm, which have a pH value in a 50% mixture with distilled water of 5-7 and 2-30 wt .-% polyisocyanate with a boiling point of more than 150 ° C at 1 Torr and used this is shaped optionally after adding water and other auxiliaries and then at room temperature and Ingress of humidity and / or heating, possibly under pressure, hardens.

Inorganic hollow spheres are understood to be those which consist of more than 95% by weight of inorganic material. They have a bulk density of less than 800 g / l, preferably 200-6OO g / l. The grain diameter is less than 1 mm, preferably between 3 and 500 microns. The hollow pearls can be used as a sieved fraction with a narrow grain size distribution however, they are preferably used unfractionated with a broad grain size distribution. Are preferred Hollow beads in spherical shape that are not or only slightly porous. If you make a 50% suspension of the hollow spheres in distilled water, this suspension should not have a pH value above 7 after 24 hours. The pH value is preferably between 6 and 7.

Hollow beads that meet these requirements are known and are commercially available. They are made of silica or quartz, from clays, from non-basic glasses, preferably from, optionally iron-containing, aluminosilicates. For example, they have the following chemical composition:

Silica as SiO ₂ - 50 - 65%

Alumina as Al ₃ O ₃ = 20 - 35%

Iron oxide as Fe ₃ O ₃ = 2 - 15%

Le A 17 899 - 4 -

809840/0297

Calcium as CaO Na ₂ O + = 0, 1 - 0.9% Magnesium as MgO K ₂ O = o, 5 - 4% Alkaline £ Components, J - o, 3 - 5%

Such beads can, especially after careful drying, for example by heating to 150-25O ° C with the invention Surprisingly, polyisocyanates to be used can be stored almost indefinitely in the absence of air or moisture Mixtures are processed, i.e. apparently also occur during storage when using e.g. aluminosilicate beads no catalytic effects that lead to premature changes in the consistency of the mixture.

These mixtures contain 70-98% by weight of the hollow beads, preferably 75-97% by weight, and can also contain auxiliaries such as pigments, Contain lubricants or fillers not present in hollow spherical form, provided that these are the ones to be considered not adversely affect the required storage stability.

The polyisocyanates are contained in the mixtures in amounts of 2-30% by weight, preferably 3-25% by weight. Here is from Significance that mixtures containing the polyisocyanates in amounts between about 6 and 2 wt .-% lead to moldings, which are classified in fire class A 2 according to DIN 4102 and are therefore of particular technical interest.

In order to be able to handle the mixtures safely, the polyisocyanates to be used according to the invention should not be volatile and accordingly have boiling points above 150 ° C at 1 Torr. These can be pure polyisocyanates or mixtures of polyisocyanates Act. Such polyisocyanates or mixtures preferably have average molecular weights above 300

Le A 17 899 - 5 -

809840/0297

In order to be able to shape the mixtures well, it is not always necessary, but advantageous, if the polyisocyanates used are liquid at room temperature, because the mixtures then have a certain inherent tack and can be easily introduced into joints, for example, as a raw molding have a good cohesion and can adapt well to complicated shapes.

Polyisocyanates, which are not volatile and are therefore to be regarded as safe, have at least 2 isocyanate groups in the molecule, however, they can also be tri-, tetra- and higher functional.

Preference is given to using polyisocyanates obtained by phosgenation accessible from aniline-formaldehyde condensates and by distilling off or by extracting volatile components have been refined to reactants of the low volatility set forth. Such polyisocyanates are in trade. They are generally by-products of the production of pure diphenylmethane diisocyanate, which, in addition to this diisocyanate, contain proportions of multinuclear polyisocyanates. It has been shown that just such technical polyisocyanate mixtures of the type described can be used particularly well in accordance with the process, which at Are liquid at room temperature and have a high proportion of such highly condensed polyisocyanates with a three-core and multi-core character contain.

In addition to this preferred group of polyisocyanates come of course also other aromatic, araliphatic and aliphatic Consider polyisocyanates that meet the requirement of non-volatility. These are especially those that are liquid at room temperature and have molecular weights above 300, preferably have over 400.

Le A 17 © 9 - 6 -

809840/0297

These polyisocyanates, which can be at least bifunctional, but also tri-, tetra- and higher-functional, belong also those polyisocyanates which have a more complex composition and are obtained if one has di- and higher-functional parts Isocyanates, e.g. to allophanes, biurets and carbodiimides !! or by cyclization, e.g. to isocyanurates, to polyisocyanates with increased molecular weight and in particular those more complex polyisocyanates that are obtained when at least bifunctional isocyanates with, based on the polyisocyanate groups contained in the polyisocyanate used, stoichiometric amounts of those compounds which are at least two reactive with isocyanates Have groups, so that higher molecular weight addition compounds are formed, which in turn at least contain two isocyanate groups per molecule. Such higher molecular weight NCO-functional compounds are state of the art and are often referred to as NCO prepolymers.

Compounds that can be used for the formation of such NCO prepolymers, which have at least two isocyanate-reactive groups, compounds are in principle suitable with Zeriwitinoff-active hydrogen atoms. In addition to such Compounds with amino groups are particularly suitable for use according to the invention, especially polyhydroxy compounds Compounds containing two to eight hydroxyl groups, especially those with a molecular weight of 800 to 10,000, preferably 1,000 to 6,000, e.g. at least two, usually 2 to 8, but preferably 2 to 4, hydroxyl groups containing polyesters, polyethers, polythioethers, " Polyacetals, polycarbonates and polyester amides, such as those used for the production of homogeneous and cellular polyurethanes are known per se.

Le A 17 89 9 - 7 -

809840/0297

The one in question. Polyester containing hydroxyl groups are, for example, reaction products of polyvalent, preferably divalent, and possibly additionally trivalent Alcohols with polyhydric, preferably dihydric. Carboxylic acids. Instead of the free polycarboxylic acids can also use the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or their mixtures can be used to produce the polyesters. The polycarboxylic acids can be aliphatic, cycloaliphatic ^ aromatic and / or heterocyclic in nature and optionally, e.g. by halogen atoms, substituted and / or unsaturated.

Examples include: succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, Phthalic acid, isophthalic acid, trimellitic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, Tetrachlorophthalic anhydride, endomethylenetetrahydrophthalic anhydride, Glutaric anhydride, maleic acid, maleic anhydride, fumaric acid, dimeric and trimeric fatty acids such as oleic acid, if appropriate in a mixture with monomeric fatty acids, dimethyl terephthalate and terephthalic acid bis-glycol esters. Examples of polyhydric alcohols include ethylene glycol, Propylene glycol- {1,2) and - (1,3), butylene glycol- (1,4) and - (2,3), hexanediol- (1,6), octanediol- (1,8), neopentyl glycol, Cyclohexanedimethanol, 4-bis-hydroxymethylcyclohexane), 2-methyl-1,3-propanediol, glycerine, trimethylolpropane, Hexanetriol (1,2,6), butanetriol (1,2,4), trimethylolethane, Pentaerythritol, quinitol, mannitol and sorbitol, methyl glycoside, also diethylene glycol, triethylene glycol, Tetraethylene glycol, polyethylene glycols, dipropylene glycol, polypropylene glycols, dibutylene glycol and polybutylene glycols in question. The polyesters can have a proportion of terminal carboxyl groups. Also made of polyester

Le A 17 899 - 8 -

809840/0 2 97

Lactones, e.g. fc-caprolactone or hydroxycarboxylic acids, e.g. tu-hydroxycaproic acid can be used.

The at least }

two, usually two to eight, preferably two to \

three, hydroxyl-containing PolyKther are such!

of the type known per se and are e.g.

merization of epoxides such as ethylene oxide, propylene oxide, |

Butylene oxide, tetrahydrofuran, styrene oxide or epichloro | hydrin with itself, for example in the presence of BF ^, or \ through the addition of these epoxides, optionally in the gel

mixed or in succession, of starting components with reac-;

capable hydrogen atoms such as water, alcohols, \

Ammonia or amines, such as ethylene glycol, propylene ^;

glycol- (1,3) or - (1,2),? rimethylolpropane, 4,4'-dihydroxydiphenylpropane, aniline, ethanolamine or
Ethylenediamine produced. Also sucrose polyether,
as they are, for example, in the German interpretative publications
1,176,358 and 1,064,938
according to the invention in question. In many cases, those polyethers are preferred which are predominantly (up to 90% by weight,
based on all existing OH groups in the polyether)
have primary OH groups. Also modified by vinyl polymers polyethers, such as those by
Polymerization of styrene and acrylonitrile in the presence
of polyethers (American patents
3 383 351, 3 304 273, 3 523 093, 3 110 695, German
Patent specification 1,152,536) are suitable, as are polybutadienes containing OH groups. \

Among the polythioethers are in particular the condensates |

cation products of thiodiglycol with itself and / ϊ

or with other glycols, dicarboxylic acids, formaldehyde, jj

Aminocarboxylic acids or amino alcohols listed. Each \

after the co-components it is the product I polythio mixed ethers, polythioether esters or polythioether ester amides.

Le A 17 899 - 9 -

809840/0297

As polyacetals come e.g. those from glycols, such as diethylene glycol, triethylene glycol, 4,4'-dioxäthoxydiphenyldimethylmethan, Hexanediol and formaldehyde preparable compounds in question. Also through polymerization cyclic acetals can be produced according to the invention suitable polyacetals.

Polycarbonates containing hydroxyl groups are those of the type known per se, e.g. by converting diols such as propanediol (1,3), butanediol (1,4) and / or hexanediol (1,6), diethylene glycol, Triethylene glycol or tetraethylene glycol produced with diaryl carbonates, e.g. diphenyl carbonate, or phosgene can be.

The polyester amides and polyamides include, for example, those made from polyvalent saturated and unsaturated carboxylic acids or their anhydrides and polyvalent saturated and unsaturated amino alcohols, diamines, polyamines and their mixtures, predominantly linear condensates.

Polyhydroxy compounds already containing urethane or urea groups and optionally modified natural polyols, such as castor oil, carbohydrates or starch, can also be used. Addition products of alkylene oxides to phenolformaldehyde resins or even with urea-formaldehyde resins are used according to the invention.

Le A 17 899 - 10 -

809840/0297

Representatives of these compounds to be used according to the invention are, for example, in High Polymers, Vol. XVI, "Polyurethanes, Chemistry and Technology", written by Saunders-Frisch, Interscience Publishers, New York, London, Volume I, 1962, pages 32-42 and pages 44-54 and Volume II, 1964, pages 5-6 and 198-199, as well as in the Kunststoff-Handbuch, Volume VII, Vieweg-Höchtlen, Carl-Hanser-Verlag, Munich, 1966, e.g. on pages 45-71, described.

Mixtures of the abovementioned compounds with at least two opposite isocyanates can of course be used reactive hydrogen atoms with a molecular weight of 400-10,000, e.g. mixtures of polyethers and polyesters can be used.

As starting components optionally to be used according to the invention there are also compounds with at least two isocyanate-reactive hydrogen atoms with a molecular weight of 32-400 in question. Even in this case this is understood to mean hydroxyl groups and / or amino groups and / or thiol groups and / or Compounds containing carboxyl groups, preferably compounds containing hydroxyl groups and / or amino groups, which serve as chain extenders or crosslinking agents. These connections show in the Usually 2 to 8 isocyanate-reactive hydrogen atoms, preferably 2 or 3 reactive hydrogen atoms.

Le A 17 899 - 11 -

809840/0297

Examples of such compounds include: ethylene glycol, propylene glycol (1,2) and - (1,3), butylene glycol {1,4) and - (2,3), pentanediol (1,5), hexanediol (1,6), octanediol- (1,8), neopentylglycol, 1,4-bishydroxymethyl-cyclohexane, 2-methyl-1,3-propanediol, glycerine, trimethylolprcpane, hexanetriol- (1,2,6), TrI- methylolethane, pentaerythritol, quinitol, mannitol and sorbitol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycols with a molecular weight of up to 400, dipropylene glycol, polypropylene glycols with a molecular weight of up to 400, dibutylene glycol, dibutylene glycol, dihydric glycol, polybutylene glycol with a molecular weight of up to 400, hydroxymethyl-hydroquinone, ethanolamine, diethanolamine, triethanolamine, 3-aminopropanol, xthylenediamine, 1,3-diaminopropane, i-mercapto-3-aminopropane, 4-hydroxy- or -amino-phthalic acid, succinic acid, adipic acid, hydrazine, Ν, Ν ' -Dimethylhydrazin, 4,4'-diaminodiphenylmethane, toluene diamine, methylene bis-chloroaniline, methylene bis-anthranil acid esters diaminobenzoic acid esters and the isomeric chlorophenylenediamines.

In this case too, mixtures of different compounds having at least two isocyanate-reactive hydrogen atoms with a molecular weight of 32-400 can be used.

Le A 17 893 - 12 -

809840/0297

With the help of this NCO prepolymer technique can also be volatile polyisocyanates are converted into modified polyisocyanates that meet the requirements outlined above Non-volatility suffice.

Polyisocyanates which are suitable for the preparation of such complex polyisocyanates with greatly reduced volatility are aliphatic, cycloaliphatic, araliphatic ^, aromatic and heterocyclic polyisocyanates such as are used, for example, in US Pat. B. by W. Siefken in Justus Ileblfs Annalen der Chemie, 562, pages 75 to 136, are described, for example ethylene diisocyanate, 1,4-tetraethylene diisocyanate, 1,6-Heacamethylene diisocyanate, 1,12-dodecane diisocyanate, cyclobutane-1, 3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate and any mixtures of these isomers, i-isocyanato-S ^ .S-tri methyl-5-isocyanatomethyl-cyclohexane (DAS 1 202 785, American patent 3 401 190), 2,4- and 2,6-hexahydrotoluylene diisocyanate and any mixtures of these isomers, hexahydro-1,3- and / or -A , 4-phenylene diisocyanate, perhydro-2,4 ¹ - and / or ^^ ' -diphenylmethane diisocyanate, 1,3- and 1,4-phenylene diisocyanate, 2,4- and 2,6-toluene diisocyanate and any mixtures of these isomers, diphenylmethane-2,4 ¹ - and / or -4,4'-diisocyanate, Naphthylene-1,5-diisocyanate, triphenylmethane-4,4 ', 4 ^H -triisocyanate, polyphenyl-poOjmethylene-polyisocyanate, as obtained by aniline-formaldehyde condensation and subsequent phosgenation and aB in British patents 874 430 and 848 671, m- and p-isocyanatophenylsulfonyl isocyanates according to American patent 3 454 606, perchlorinated aryl polyisocyanates, as described, for example, in German Auslegeschrift 1 157 601 (American patent 3 277 138 ) , Polyisocyanates containing carbodiimide groups, as described in German Patent 1 092 007 (American Patent 3 152 162)

Le A 17 899 - 13 -

809840/0297

are described »Diisocyanates as described in US Pat. No. 3,492,330, polyisocyanates containing allophanate groups, as described in 8.B. in British patent specification 994 890, Belgian patent specification 761 626 and published HollXndl patent application 7 102 524, polyisocyanates containing isocyanurate groups, such as those described, for example, in American patent specification 3 001 973, in German patents 1 022 789, 1 222 067 and 1,027,394 and in German Offenlegungsschrift 1,929,034 and 2,004,048, polyisocyanates containing urethane groups, as described in Belgian patent 752 261 or in American patent 3,394,164, polyisocyanates containing acylated urea groups according to the German patent 1,230,778, polyisocyanates containing biuret groups, such as those described, for example, in German Patent 1,101,394 (American Patents 3,124,605 and 3,201,372) and in British Pat P. atentschrift 3,654,106 describes estergruppen containing polyisocyanates as they are described for example in British Patents 965,474 and 1,072,956, referred to in United States Patent Specification 3,567,763 and in German Patent 1,231,688, imple- mentation products of the abovementioned isocyanates with Ac βtale n according to German patent specification 1,072,385 , polyisocyanates containing polymeric fatty acid residues according to American patent specification 3,455,883.

It is also possible to use the distillation catalysts containing the isocyanate groups obtained in the technical isocyanate production, optionally dissolved in one or more of the abovementioned polyisocyanates. It is also possible to use any desired compositions of the aforementioned polyisocyanates.

Le A 17 83 9 - 14 -

809840/0297

As a rule, those that are technically easy are particularly preferred accessible polyisocyanates, e.g. 2,4- and 2,6-tolylene diisocyanate and any mixtures of these isomers ("TDI"), Polyphenyl-polymethylene-polyisocyanates, such as those produced by aniline-formaldehyde condensation and subsequent phosgenation ("crude MDI") and carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or polyisocyanates containing biuret groups ("modified polyisocyanates").

Le A 17 899 - 15 -

80984070297

The mixtures of inorganic hollow beads and non-volatile polyisocyanates to be used according to the method are exposed to moisture cured in the form of water or steam. It is surprising that in contrast to other cast resin systems the substance that acts as a hardener, namely the water in the mixture, is also a fully satisfactory one Effect develops when it is not homogeneously distributed in the binder. For example, if water is added to the mixture, a simple brief mixing by means of a mixing drum or a stirrer is sufficient for hardening, with the Isocyanate normally immiscible water is by no means homogeneously distributed in the overall mixture.

The hardening is still surprisingly insensitive to this the amount of water used. In addition to the simple access of air humidity or water vapor, e.g. when storing the preformed mixture at room temperature, amounts of water from 0.1 to 20% by weight and higher, based on the total mixture used, are used. Preferably 0.5 to 10 wt .-% Water added to the mixture before the deformation process. But it is also possible to use anhydrous moldings in To harden water vapor.

_{Furthermore, it is surprising that the CO 2} produced during the hardening brought about by the reaction of the water with the polyisocyanate, even with relatively high polyisocyanate contents, for example around 20% by weight, even when the press is operated at about 150 ^° C. does not explode or damage the molded part obtained. The tendency of some polyisocyanates to foam up on reaction with moisture does not appear to have any adverse effect on the moldings obtainable according to the process either.

Le A 17 899 - 16 -

809 8 4 0/0297

The further fillers and auxiliaries to be considered according to the process can either be the mixture of inorganic Hollow beads and non-volatile polyisocyanates can be added or, for example, the water used if necessary Mixture can be added immediately before the "forming process".

The latter case occurs when the auxiliaries are substances that react with the isocyanates. Emulsifiers, water repellants, pigments such as TiO ₂ , carbon black, chromium oxides, iron oxides, dyes, fluxes such as fluorspar, borates, organic or inorganic halogen compounds, metal powders, alkali or alkaline earth silicates, calcium sulfates, cements or other fillers other than Hollow spherical shape, for example in the form of powders with massive particles, the grain size of which should also be below 1 mm. The amounts of these auxiliaries are preferably such that the weight limits for the content of hollow beads and polyisocyanate in the molded mixture to be observed according to the process are not violated, ie that the molded mixture contains at least 70% by weight of inorganic hollow beads and at least 2% polyisocyanate.

Furthermore, the following are understood as aids: activators or modifiers for the steering or acceleration of the Isocyanate curing reaction, such as alkali metal alcoholates or carboxylates, e.g. sodium acetate, tin octoate, iron acetylacetonate, Amine activators known in polyurethane chemistry, such as tertiary amines such as triethylamine, Tributylamine, N-methyl-morpholine, N-Xthyl-mor-

Le A 17 899. - 17 -

809840/0297

Le A 17 899 - 18 -

809840/0297

pholine, N-cocomorpholine, N, N, N ', N'-tetramethyl-ethylenedi- I amln, 1,4-diaza-bicyclo- (2,2,2) -octane, N-methyl-N'-dimethyl-

amlnoethyl-piperazine, Ν, Ν-dimethylbenzylamine, BIs- (N, N-di- j

äthylaminoäthyl) adipate, Ν, Ν-diethylbenzylamine, pentamethyl [

diethylenetriamine, Ν, Ν-dimethylcyclohexylamine, N, N, N ¹ , N ¹ - |

Tetramethyl-1,3-butanediamine, Ν, Ν-dimethyl-ß-phenylethyl- I

amine, 1,2-dimethylimidazole _K 2-methylimidazole. As a catalysis \

gates also come from Mannich bases known per se from secondary if

Amines, such as dimethylamine, and aldehydes, preferably |

Formaldehyde, or ketones such as acetone, methyl ethyl ketone or I.

Cyclohexanone and phenols such as phenol, nonylphenol or bis- |

phenol in question. I.

Tertiary amines containing hydrogen atoms active towards isocyanate groups as catalysts are, for example
Triethanolamine, trilsopropanolamine, N-methyldiethanolamine, N-ethyl-diethanolamine, N, N-dimethyl-ethanolamine, and their reaction products with
Alkylene oxides such as propylene oxide and / or ethylene oxide.

Of the activators, those of particular interest are
which are not very volatile and physiologically largely harmless
are, for example, alkanolamines or N-alkylalkanolamines, in particular triethanolamine and its oxyalkylation products and
Oxyalkylation products of ethylene or propylene diamine.

While the usual amine activators in amounts of O, O1 to
3% by weight based on isocyanate can be used
it is, for example, a weakly effective activator with triethanolamine
advisable to use amounts of 0.5-10, preferably 1-5% by weight
on isocyanate, to use if you want to achieve strong acceleration effects.

In addition, auxiliaries are also understood to be those compounds, which can serve as plasticizers or elasticizing reactants for the isocyanate. Such connections correspond to the compounds that are already considered compounds with at least two Zerewitinoff-active hydrogen atoms in the Production of any prepolymers to be used were listed on page 5. Again, there are polyhydroxyl compounds of the type mentioned should preferably be considered.

The mixtures according to the process are produced by customary methods, e.g. by tumbling on, spraying on in mixing drums, Special mixers or kneading units, kneading screws, etc. These mixtures can be stored if they are excluded of activating substances very well, e.g. in the case of the preferred hollow bead types with a weakly acidic reaction in water, if the hollow beads beforehand at an elevated temperature, around 150-25O ° C were dried. Of course, moisture exclusion is necessary, e.g. by using appropriately equipped silos or containers or in tin drums that can be soldered or in welded, polyolefin-coated aluminum foil packs. If you want to process a freshly prepared mixture immediately, protective measures are not necessary, because a freshly prepared mixture can be processed for several hours even after the addition of water, provided that Temperatures below 25 ° C are maintained. Of course, this processing latitude is with the use of accelerators less.

The mixtures, optionally containing accelerators, can be subjected to cold forming without further addition of water Stamping, rolling, pressing, extruding, shaking in, blowing in, etc. at room temperature or elevated temperatures Cure exposure to air humidity or water vapor. When working at elevated temperatures, e.g. between 50 and 180 ° C

Le A 17 899 - 19 -

809840/029 7

be

or when introducing the mixtures into closed molds, it is of course advisable to use Water. The hardening depends on the temperature and is also dependent on the geometry of the molded part or the given temperature. depending on the thermal conductivity of the molded part. Accordingly, curing times can range from a few seconds up to about Occur 24 hours and more. Even with parts that are manufactured at elevated temperatures, e.g. in the press were, post-reactions are still possible, the strength of the molded part is generally improved somewhat on storage. Parts hardened by humidity at room temperature reach their final strengths depending on their geometry possibly only after approx. 30 days, similar to concrete parts.

A particular advantage of the method according to the invention is;

the possibility of cold forming the previously manufactured I.

Mixtures, while the hardening then, if necessary, at |

elevated temperature is made. So is a special |

Procedure for the production of moldings with special J

This low density is characterized in that the |

according to the invention, optionally water and other help- '>

Medium-containing mixture of hollow beads and polyisocyanates ί

is first converted into the form of preforms and \. these preforms can then be used to produce the final molded article.

These, for example, extruded preforms have the shape of cylinders with diameters of approx. 1-10 mm or of small tubes, hemispheres, pipe half-shells or twisted tapes with similar diameters and are then filled in the form of smaller fragments or continuously in forms such as a plate shape and there compacted under low pressure and then hardened. The density of panels produced in this way can be 50-200 kg / m ³ lower than panels produced directly from the mixture

Le A 17 899 -2O-

809840/0297

Another interesting processing variant is characterized in that the optionally water and further Mixture containing auxiliaries by a piston or Screw injection molding machine or other conveying units, in which, if necessary, even the mixture production itself can be made, at temperatures between 0 and about 100 ° C, preferably 15 and 60 ° C is injected into a closed mold or presses, which either immediately after filling or previously to temperatures between 100 and 250, preferably 120 and 180 ° C »is heated. To this Way can be from the mixtures according to the invention in short cycle times produce moldings.

The simplest way of processing the mixtures, which may contain water, accelerators and other auxiliaries, is tamping, pouring or blowing into a mold and then allowing to harden, optionally under pressure and heating. Interestingly, the production is of sheet goods on pressing at temperatures between 1OO and 25O ° C, preferably from 12O to 180 ⁰ C, and pressures of from 0.5 to about 50 kp / cra.

Of course, internal or, preferably, external release agents can be used in the production of molded parts. aside from that is the introduction of reinforcement elements into the molded parts in the form of metal or non-metal rods or wires, -fibers, -woven, -woven, -knit into consideration.

The mixtures or molded parts obtainable from them can be used for insulation purposes, e.g. in the form of pipe half-shells or building blocks and plates are used as binders for pumice, expanded glass or expanded clay particles, as putty or mortar or as everyday objects, Components, cover panels, acoustic panels, for the production of wall elements, filters, sandwich constructions

Le A 17 899 - 21 -

809840/0297

with the help of various top surfaces, these top surfaces e.g. can be applied in one operation during the production of press plates. The molded parts can be as Carriers for fragrances and biological agents are used as a floating body, filler or joint filler material, as Plaster or coatings for rigid substrates, as a fire-retardant and insulating filling or sealing compound for structural cable and pipe penetrations, as screeds, as material for furniture production or semi-finished products for further processing, mostly using machining processes. The moldings are also after thermal stress up to approx. 30 ° C and stable when stored in water.

The hardened molded parts can be sawn, nailed, screwed or glued. You can use hydraulic binders or coated with organic layer formers based on latices, dispersions, solutions, pastes or melts will. They can be painted, galvanized or laminated after appropriate pre-treatment, whereby due to the in the area of brick lying low thermal expansion coefficient of the molded body to the correct one Dimensioning and selection of the top layers must be taken into account. As a bonding agent, e.g. in lamination with Metals or wood and other outer layers, often polyolefins or copolymers of olefins with e.g. vinyl acetate, Acrylates and / or (meth) acrylic acid have been tried and tested, which result in a good bond during the pressing process. Of course you have Adhesives based on epoxies or e.g. polyvinyl acetate dispersions have also proven to be suitable.

In the following, the method is to be explained by way of example. The parts and percentages given are based on weight.

Le A 17 899 - 22 -

809840/0297

Hollow balls with closed walls are used as inorganic hollow balls, for example the following Composition or properties have:

Silica as SiO ₂ Na ₂ O + - 55 - 60% Alumina as Al ₂ O-, K ₂ O - 25th - 30% Iron oxide as Fe ₂ O, - 4th - 10% Calcium as CaO »0.2 - 0.6% Magnesium as MgO " 1 - 2% Alkaline "7
Components - * - 0.5 - 4%

Shape: small, hollow glass spheres Color: light gray

Specific weight: 0.6 Bulk weight: 400 g / l Fineness: 10 - 250 microns Average grain size: 100 microns

15% below 50 microns 20% above 125 microns

Wall thickness: approx. 10% of the diameter. Melting point: 1,200 ° C

Hardness: Mohs scale 5

A 50% suspension of the hollow spheres in dist. At room temperature, water has a pH of 6.3 after 24 hours.

The polyisocyanate used is, for example, a polyisocyanate which is liquid at room temperature and which is industrially produced by phosgenation of aniline-formaldehyde condensates and distilling off the volatile components and part of the formed Diphenylmethandiisocyantes is obtained. It is about accordingly a polyisocyanate from the sump of the technical

Le A 17 899

- 23 -

809840/0297

Production or distillation of diphenylmethane diisocyanates, The polyisocyanate used, which in addition to phenylmethane diisocyanate also contains complex multinuclear isocyanates, is characterized as follows

Isocyanate content 30-32%

hydrolyzable chlorine: max. 0.3%

Total chlorine: max. 0.8% Viscosity at 25 ° C: 400 - 50 c Sediment: max. 1% Density dj * 1.235 g / cm ³ Viscosity at 20 ° C: 580 - 100 cP Flash point: over 200 ° C Boiling point at 1 Torr above 150 ° C

A closed propeller mixer is used to produce the mixture, so that mixtures can also be excluded can be carried out by humidity.

The percentages in the following examples are always percentages by weight, unless stated otherwise.

Le A 17 899 - 24 -

809840/0297

example 1 Preparation of a storage-stable premix

The hollow spheres are dried ^{at 150 ° C. for 24 hours.} Then you put them in the mixer filled with dried air and start the mixing propeller. 7.5 parts of the polyisocyanate are then metered into 92.5 parts of the beads in about 5 minutes. After a further 5 minutes the mixture is homogeneous; under the microscope it can be seen that all hollow spheres are coated with the polyisocyanate. The mixture is filled into polyethylene-lined metal drums with the exclusion of atmospheric moisture, and the drums are hermetically sealed.

The freshly made premix feels like moist earth. It can be deformed by pressing and pounding without, for example, a shaped ball falling apart again. The appearance is very similar when one produces mixtures that do not contain 7.5 but between 3 and 15 % polyisocyanate.

When lying in the air (50% rel. Humidity pa. ), The character of the non-compacted mixtures changes; they become less sticky, clump together and are no longer deformable after approx. 24 hours.

In the closed drums, the premix retains its consistency for at least five months; after 8 months the premixes can be deformed. A sample is then taken from the drum and left in the air, the property change described above takes place again.

Le A 17 899 - 25 -

809840/0297

Example 2 Manufacture of moldings

One 3 months with exclusion of moisture in a metal turret with a polyethylene bag stored mixture of the hollow beads and a predetermined amount of polyisocyanate is with a given amount of water in a drum mixer for approx. 3 minutes.

The mixture is then poured into a plate form to form a 4 cm thick plate, which is tamped with a small Rammer is compacted by hand.

The plate produced in this way is then cured at a predetermined temperature in a hot air cabinet, the curing time being between hours and days. Then the Plate cut out at different points and in different cutting directions Test specimens with the dimensions 4 χ 4 χ 16 cm and examined for compressive strength and flexural strength. Within the error limits, the strength values of the test specimens made from a plate are the same, regardless of the cutting direction, the following are in detail Values summarized in tabular form receive:

Tables A-C show the dependency of the mechanical values for different water additions as a function of the Curing temperature. In connection with A-C, Table D clarifies the relationships between amounts of used Polyisocyanate and mechanical values.

It is clear that there is a wide range of tolerances with regard to the amount of water that can be used. On the other hand, the great influence of temperature is evident. Nevertheless, it should be noted that one can reach at least the compressive strengths available at 70 ⁰ C at room temperature when it is measured the cure only big enough here.

Le A 17 899 - 26 -

809840/0297

The hardening properties of the mixtures according to the process are shown in Table E for room temperature. The hardening is carried out with a needle device based on DIN 1164 certainly. It turns out that with triethanolamine as an easily manageable accelerator, the times for hardening are about can cut in half.

Example 3

This effect is also observed in compression tests that are carried out in Table 7 are shown. For this purpose, the freshly prepared mixture or the mixture taken from the storage vessel is mixed with something Water and optionally dissolved accelerator (triethanolamine) are stirred, then shaken in a plate shape and under low pressure at elevated temperature <150 ° C). It can be seen that the hardening proceeds, as expected, starting from the heated press rams towards the center of the plate. Sufficient hardening in the middle of the panel depends on the temperature reached there or reaction rate at this temperature, i.e. on the thermal conductivity of the plate material. The relatively long minimum pressing time caused by this can be achieved by the The addition of accelerators can be significantly reduced, with the mechanical values even increasing.

If you put a polyethylene-coated aluminum foil in the plate form so that the polyethylene surface is facing the plate material and covers the plate from above as well from, one obtains in a pressing process e.g. according to experiment F, e, an Al-coated press plate (sandwich) with good adhesion between the plate material and the cover layer.

Le A 17 899 - 27 -

809840/0297

► · · I

The same procedure can be used with a polyester fabric that is coated on one side with an ethylene-acrylic acid copolymer is.

If you put a polyamide fleece in the mold in an analogous procedure brings in, you get a plate that is firmly provided on one or both sides with a textile layer and itself suitable as wall cladding.

If you put a plywood sheet into the plate shape, on top of it an approx. 0.3 mm thick sheet of polyethylene, that through Addition of an ethylene-acrylic acid copolymer is modified, then overlaid with the mixture according to the invention according to Experiment F, b or F, f, you get one in one pressing process Veneer-coated press board, which is suitable as a semi-finished product for the production of furniture with reduced flammability.

Example 4 Manufacture of compression molded articles

A mixture of 100 parts of the hollow beads and 15 parts of the polyisocyanate is prepared in a propeller mixer. A solution of 0.5 part of triethanolamine in 3 parts of water is then added in the same mixer.

The freshly made mixture is put into a screw injection molding machine at an operating temperature of approx. 20 ° C, and in a steel one provided with a silicone-based release agent Injection molded flower pot that is heated to 150 ° C. To 3 minutes is removed from the mold. The flower pot obtained has a weight of 150 grams. Since its walls are slightly porous, it is particularly well suited for plant purposes.

Le A 17 899 - 28 -

809840/0297

Example 5

Manufacture of molded articles from preforms ;

A mixture stored for 5 weeks according to Example 1 is removed from the pack and mixed with 3% by weight of water. Now \, the mixture is passed through a steel mesh with square [

loosely filled into a mold and pressed lightly
compacted to a 10 cm thick plate. This will
Cured overnight at 80 ° C. The resulting plate
has a compressive strength of approx. 6 Kp / cm and a density of only 290 kg / m. A plate made in the same way,
in which, however, only half the amount of polyisocyanate is used
was, had a density of 300 kg / cm
Compressive strength of 3.5 Kp / cm. As they meet the requirements
corresponds to fire class A1 according to DIN 4102, it can be used particularly well for insulation purposes.

Le A 17 899 - 29 -

809840/0297

Holes with an edge length of 0.9 mm pressed. Here \ strands that together have a tenuous cohesion but i retain their shape emerge. These strands are now |

Tabel

-J co

VO

OO O CO OO

mixture

% Content of polyisocyanate 7.5

additive

% Water

Curing temperature

Cure time d - days

Volume weight kg / m ³

0 compressive strength kp / πΤ (DIN 1164)

0 flexural strength kp / πΓ (DIN 1164)

Heat transfer coefficient (plate 30 χ 30 cm) W / km

thermal expansion coefficient

0 2.5 room temperature 8 days

414 23.5 9.5

410 29.2 8.8

7.5

12.5 15

411 26.0 9.1

409

422

25th

421

26.6 26.7 26.8 25.4 10.1 9.4 9.1 8.1

f
(P
> Table B. vj mixture
% Content of polyisocyanate VO
VO additive
% Water Curing temperature Curing time
h - hours OO
°
co Volume weight
kg / m ³ 00
jr-
CD 0 compressive strength
kp / πΓ (DIN 1164) / 02 U) 0 flexural strength
kp / πΓ (DIN 1164) co
<» Heat transfer coefficient
(Plate 30 χ 30 cm)
W / km

£ herm. Expansion coefficient

70 ^BC

2.5

24 hours -

406 419

7.5 10 12.5 15

418 422 422

420 417

37.7 39.8 30.7 33.8 32.5 33.8 32.2 30.3

15.0 11.6 8.6 10.9 12.1 11.2 11.1 10.8

0.1

CjO CO 00

t ¹ (D

Tabel

O NJ CD

Ul to

mixture

% Content of polyisocyanate

Addition% water

Curing temperature

Hardening time h - hours

Volume weight kg / m ³

0 compressive strength kp / πΓ (DIN 1164)

0 flexural strength kp / πΓ (DIN 1164)

Heat transfer coefficient (plate 30 χ 30 cm) W / km

thermal expansion coefficient

7,
O H - 2 , 5 5 7th , 5 10 12, 5 15th ?
25th 3 V

410

406

393 406

401 398 405

46.6 48.0 48.2 38.3 43.2 44.3 39.5 51.5 20.3 20.1 18.2 16.9 17.3 19.8 16.6, 19.7

7.8-10

-6

CO CO 00

O CD OO

O isj CO

Tabel

, 00

| \ g mixture

% Content of polyisocyanate

Addition% water

Curing temperature Curing time

h - hours / day - days

Volume weight kg / ra ³

0 compressive strength kp / nr (DIN 1164)

0 flexural strength kp / m ^z (DIN 1164)

Heat transfer coefficient

(Plate 30 χ 30 cm) W / km

thermal expansion coefficient

a 3

7.5 20th

8 days 397 12.8 5.2

b 3

c 7.5

7.5 7.5

150 20

12 days 4 days

437 423

27.1 15.3

10.7 5.2

d 7.5

7.5 20

e 10

70

f 10

20th

7.5 7.5 7.5

70

Day 24 h 24 h 24 h

457 428 470

H 20th

7.5 150 24 h 466

37.2 44.7 69.7 69.9 98.5 10.6 16.8 25.1 20.9 41.5

CO O CD OO

ro

(D

VO

Tabel

mixture

% Content of polyisocyanate

Addition% water

% Triethanol amine

based on polyisocyanate

Temperature ⁰ C

Start of hardening after min (DIN 1164)

End of hardening after h (DIN 1164)

a
7.5

7.5

20th

400

b
7.5

7.5

190

c 7.5

7.5

6 20

160

Ir
(D mixture tab ell e 5 F. C. d e f > % Content of polyisocyanate a b -J additive 20th 7.5 7.5 7.5 00
VO % Haters 3 7, VO % Triethanolamine 3 3 3 - 3 based on polyisocyanate 3 3 Plate thickness - 2 - 2 cm - - Pressing temperature 4th 4th 2 2 location Press pressure 4th 4th 150 150 150 150 σ bar 150 150 co
OO Minimum pressing time 10 10 10 10 ο I. Min 10 10 O ω 0 compressive strength (DIN 1164) 9 25th 10 10 5 ro UI Kp / m 20th 20th 7th co ¹ 0 flexural strength (DIN 1164)
kP / πΤ 118.6 64.5 Volume weight 26.1 48, 49.0 21.0 Kg / m 9.3 14, 507 423 412 422

Claims (4)

1. Storage-stable, cold-deformable molding compounds consisting of 70-98% by weight of inorganic hollow spheres with a bulk weight of less than 800 g / l and grain diameters of less than 1 mm, the in 50% suspension in water have a pH of 5-7, with 2-30 wt .-% polyisocyanate with a Boiling point of more than 150 ° C at 1 Torr are coated. 2. A process for the production of molded parts with largely isotropic properties and weights per liter of less than 1000 grams from stable, cold-formable molding compositions according to claim 1, characterized in that the cold-formable molding compositions are mixtures of 70-98% by weight of inorganic hollow spheres with a bulk density of less than 800 g / l, grain diameters below 1 mm, which have a pH value of 5-7 in 50% suspension in water and I use 2-30% by weight polyisocyanate with a boiling point of more than 150 ° C at 1 Torr, and this, if appropriate }, after the addition of water and further auxiliaries, is deformed j and cured at room temperature and ingress of atmospheric moisture j and / or heating, if appropriate under pressure. 3. The method according to claim 2, characterized in that one serving as starting material molding material by means of a \ conveyor device into a closed mold and pushing in | this hardens at temperatures between TOO and 25O ° C. \ 4. The method according to claim 2, characterized in that i firstly f preforms are produced from the molding compound serving as starting material, these are then transferred into a mold and cured there, optionally after compaction. j Le A 17 899 - 36 - 809840/0297