CH624693A5 - Process for the production of mouldings having a cell structure - Google Patents

Description

624 693

2nd

PATENT CLAIMS

1. Process for the production of molded parts with a cell structure by polymerization or curing emulsions of 25-90 parts by weight of water in 75-10 parts by weight of a polymerizable or curable, liquid resin-monomer mixture in the presence of Catalysts at normal or elevated temperature under shaping, characterized in that in the emulsion at least 5% by weight, based on the finished emulsion with all the additives, of a non-combustible inorganic substance or mixture of substances or in finest distribution in powder form with an average Grain size of not more than 50 [i diameter evenly distributed and the emulsion is adjusted in its degree of dispersion so that a predominantly open cell structure is formed after the polymerization or curing and the water introduced is easy to remove by drying, and that the emulsion is Shaping and maintaining at least 90% of that with the water-in-oil emulsion The total volume is polymerized or cured and then the drying of the molded part lowers its unbound water content to 0 to 8% by volume.

2. The method according to claim 1, characterized in that the non-combustible inorganic substances or mixtures are used which release water at a higher temperature.

3. Process according to claims 1-2, characterized in that non-combustible inorganic substances or mixtures of substances are used which release carbon dioxide when exposed to flame.

4. The method according to claims 1-3, characterized in that in addition to the non-combustible inorganic substances or mixtures of substances, which are dissolved in water or incorporated in powder form in the emulsion in the manner specified in claim 1, compounds are used which split off flame-retardant gases at higher temperatures.

5. The method according to claims 1-4, characterized in that in addition to the non-combustible inorganic substances or mixtures of substances which are dissolved in water or in powder form of the emulsion in the manner specified in claim 1, and those mentioned in claim 4 Compounds which split off flame-retardant gases at higher temperatures are added, compounds which expand at higher temperatures to form flame-retardant cover layers which form a foam which is insulating against heat and flame.

6. The method according to claims 1-4, characterized in that the moldings are additionally impregnated with compounds used in the form of a varnish or a solution, which expand at a higher temperature to form flame-retardant cover layers, which form an insulating foam against heat and flame.

7. The method according to claims 1-6, characterized in that the non-combustible inorganic substances mentioned in claim 1 in amounts of 5-30 wt .-% - based on the total weight of the finished emulsion with all additives - are stirred into this.

8. The method according to claim 1, characterized in that a residue of unbound water of 0-5% by volume remains in the molded part.

9. The method according to claim 1, characterized in that the polymerization or curing takes place in the presence of emulsifiers, wetting agents, accelerators, inhibitors, crosslinking compounds, plasticizers, fillers and dyes.

10. Molded parts produced by the process according to claim 1, the cell structure of which has a pore volume of 25-85% by volume and the majority of which are open, characterized by a non-combustible inorganic compound content of 5-20% by weight. % - based on the wet weight of the molded part - and a non-bound water content of 0 to 8% by volume - based on the total volume of the molded part.

11. Molded parts according to claim 10, characterized by a content of unbound water of 0-5 vol .-%, based on the total volume of the molded part.

Plastics are preferably used as molded parts for a wide variety of areas. They are easier to manufacture in series and have a number of advantages in terms of their strength. In many cases, however, the flammability and flammability of these plastics, which are suitable per se for the application in question, prevent such use. For example, for materials that are used as building materials and for the interior of rooms, not only the flammability per se, but also the behavior during a fire against radiant heat, the extinguishing behavior, the thermal conductivity, especially at higher temperatures above 600/800 ° C significant. There has been no shortage of attempts to make such flammable plastics flame-resistant. Halogen, phosphorus and antimony compounds are preferred. However, it has been found that with a number of plastics, many of these flame retardant components migrate to the surface of the molded part and are removed from there by mechanical influences. This results in a permanent depletion of the plastic on flame retardant components with a corresponding increase in the flammability of the plastic.

Particularly in the case of foamed plastics, there are not inconsiderable difficulties in adapting the products and molded parts produced therefrom to the requirements which are placed on flame-resistant plastics, in particular when they are used as building materials.

According to a process known from German Offenlegungsschrift 1 544 857, incombustible, sound-absorbing building or construction elements are produced in such a way that a water-in-oil emulsion of styrene and / or methacrylic acid ester and / or vinyl ester with a minimum content of 25% water polymerized out. The incombustibility is achieved in that the emulsion water largely remains in the molding or construction element and is kept in the long term.

However, it is unavoidable that the water slowly escapes from the molded parts which have been produced by this known method. This is associated with a shrinking and warping of the molded parts as well as a loss of flame resistance corresponding to the amount of water escaped.

Dewatered, hardened emulsions or emulsion foams, as they are to be called below, cannot be adequately protected against the effects of flame by the usual means due to the very large surface area.

Therefore, possibilities were sought to adjust the flame resistance of emulsion foams in such a way that the molded parts made from them withstand even high fire temperatures and this protective effect does not diminish as the density of the emulsion foams decreases.

The process according to the invention for producing molded parts with a cell structure by polymerizing or curing emulsions of 25-90 parts by weight of water in 75-10 parts by weight of a polymerizable or curable, liquid resin-monomer mixture in the presence of catalysts

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Toren at normal or elevated temperature under shaping is characterized in that in the emulsion at least 5 wt .-%, based on the finished emulsion with all additives, a non-combustible inorganic substance or mixture of substances or in the finest distribution in powder form with an average Grain size of not more than 50 (x diameter evenly distributed and the emulsion is adjusted in its degree of dispersion so that a predominantly open cell structure is formed after the polymerization or curing and the water introduced is easy to remove by drying, and that the emulsion is under Shaping and maintaining at least 90% of the total volume specified with the water-in-oil emulsion polymerized or cured and then, by drying the molded part, its content of unbound water was reduced to 0-8% by volume.

In particular, for this purpose the emulsion is first set to a degree of dispersion which is in a range which is characteristic of the emulsion in question and then polymerized or cured while shaping and maintaining at least 90% of the total volume specified with the water-in-oil emulsion, wherein The characteristic range of the degree of dispersion extends from the beginning of the dispersion, which increases in the distribution of the dispersed phase, to the beginning of the stable state of dispersion, in which the static emulsion no longer changes the phase structure under the influence of the polymerization or hardening reaction or decays due to phase change.

The drying can of course also take place at temperatures above 50 ° C, but then in a period of a few hours.

Any polymerizable or hardenable liquid substance which is emulsifiable with water is suitable per se for producing the emulsion foams by the process of the invention. The following are suitable as examples: Monomers, preferred mixtures of resins and monomers with a relatively low molecular weight, optionally mixed with organic liquids copolymerizing therewith. These monomers should usually contain at least one olefinic double bond in the molecule, for example CH2 = C <or R-CH = C <or -CO-CH = CH-CO-.

Such compounds include, for example, those which have vinyl or α-alkylvinyl groups bonded to an aromatic nucleus, such as, for example, styrene, divinylbenzene, trivinylbenzene, methylstyrene, α-methylvinylbenzene. Suitable compounds also include esters and ethers of vinyl alcohol, such as vinyl acetate, divinyl phthalate, divinyl maleate, vinyl butyl ether, divinyl ethane diol ether, and esters of acrylic or methacrylic acid, such as, for example, ethyl acrylate, 1,2-propanediol diacrylate, methyl methacrylate, ethyl methacrylate, Ethanediol methacrylate, butene-2-dioI-l, 4-dimethacrylate, cyclohexyl methacrylate or maleinates, such as diethyl maleinate and fumaric acid esters, or also olefinically unsaturated halogenated hydrocarbons or unsaturated organic cyanides, such as, for example, vinylidene chloride, allyl chloride, chloroprene, acrylonitrile and unsaturated for example isoprene, and ethers and esters of allyl or methally alcohol, such as, for example, diallyl phthalate, methallyl methyl fumarate, 1,2,3-tri (allyloxy) propane, diallyl diglycol carbonate and diallyl maleate. These and other suitable starting materials are essentially described, for example, in US Pat. No. Re 27,444, in German Pat. No. 1,137,554. Gaseous or solid monomers can also be mixed with these liquid monomers, provided that they, such as butadiene, vinyl chloride, vinyl naphthalene, vinyl carbenzene and the like, form a liquid mixture with the liquid monomer.

The monomer or monomer mixture can optionally also serve as a solvent or diluent for the resin component. This resin component can be a high molecular weight homopolymer or copolymer which is able to copolymerize with the monomers or monomer mixture. In addition to unsaturated polyesters, copolymers of styrene and butadiene are also suitable for this. Unsaturated polyesters which have condensed dihydric alcohols, such as ethanediol, 1,2-propanediol, 1,3-propanediol, diethylene glycol, l-allyl-2,3-hydroxypropanediol, on the one hand with an aβ-ethylenically unsaturated have proven particularly useful Dicarbonic acid such as maleic acid, fumaric acid and the like can be obtained. In addition, the unsaturated polyesters can also contain other dibasic and polyvalent carboxylic acids, such as, for example, endomethylene tetrahydrophthalic acid, tetrahydrophthalic acid, phthalic acid, succinic acid, adipic acid, propionic acid, benzenetricarboxylic acid, benzenetetracarboxylic acid, or else other lower alcohols, such as benzyl alcohol (1,2-di AlIyloxi) -3-propanol-Glycerol, pentaerythritol, and hydroxycarboxylic acids, such as 4-hydroxymethalcyclohexane carboxylic acid. These substances are also essentially known from US Pat. No. Re 27,444 and from German Offenlegungsschrift 2,046,575 and from German Patent Specifications 1,024,654,1 067,210 and 1,081,222. In conjunction with self-emulsifying polyesters, epoxy compounds with more than one epoxy compound can also be used as the polymerizable phase, as indicated in German Offenlegungsschrift 1,495,843.

Unsaturated polyesters which copolymerize with vinyl monomers and are dissolved in a mixture of styrene and methyl methacrylate in a weight ratio of 1: 4 to 4: 1 are particularly advantageously used. Instead of the methyl methacrylate, it is also possible to use a monomeric vinyl compound whose solubility in water is equal to or higher than that of methyl methacrylate.

In addition, high molecular weight polymers which do not copolymerize with the monomer can be added to the emulsion. These are preferably polymers of styrene, vinyl chloride, esters of methacrylic acid and optionally unsaturated polyesters which can be copolymerized with monomers such as styrene, methyl methacrylate, etc.

In order to emulsify an emulsion of the water-in-oil type, it is possible to use emulsifiers which are capable of forming water-in-oil emulsions whose molecules consist of hydrophobic and hydrophilic components which can be used individually or in a mixture. Emulsifiers which have been partially dissolved in the monomeric portion of the water-in-oil emulsion in the presence of water have proven particularly useful. The suitability of such emulsifiers can be demonstrated, for example, by a simple experiment: For this purpose, 5-10% by weight of the emulsifiers to be tested or of the mixture of emulsifiers are dissolved in the monomers of the portion of the emulsion to be polymerized or hardened, and some to about 10 cm3 of this solution Drop of water added. In the case of the particularly effective emulsifiers, the water is visibly separated.

As low molecular weight water-in-oil emulsifiers e.g. Esters of higher fatty acids with polyhydric alcohols, amides of higher fatty acids, salts of alkyl sulfonic acids can be used. From the large number of high molecular weight compounds, polymers or polycondensates have proven themselves, which are completely or almost water-insoluble and hydrophilic groups, such as carboxyl, carboxylate, carboxamide, hydroxyl groups, ester or ether groups, amino, ammonium, sulfonic acid - And / or contain sulfoxide residues.

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Such emulsifiers are described, for example, in German Patent 1 301 511. Copolymers with an acid number between 8 and 12, which consist of a polymerizable carboxylic acid, such as acrylic acid on the one hand and styrene on the other hand, and in which the free carboxyl groups are completely or partially neutralized with organic or inorganic bases, can be used with equal success. Polymers or copolymers of styrene, methyl methacrylate or vinyl acetate can also be used as emulsifiers if these polymers or copolymers have been produced in the emulsion polymerization process in the presence of persulfates and consequently contain sulfonic acid residues. Saturated and unsaturated polyesters can also be effective as emulsifiers, especially if they have been partially or completely saponified with alkalis or if they contain a sufficient number of free hydroxyl groups. These emulsifiers are described in more detail, for example, in German patent application 1 199 982 or in German patent document 1 267 845. These can be the same polyesters that can also be used as a resin component of the resin-monomer mixture. Graft copolymers which can be produced from styrene in the presence of polyalkylene oxides and are described, for example, in German Laid-Open Specification 1,169,671 can also be used as emulsifiers. Film-forming polymers, such as, for example, cyclo rubber or copolymers of vinyl compounds with a radical containing 8 C atoms, which are described in German Patent Specification 1,148,382, can also be used as emulsifiers. Hydrophobic polymerization products of organic compounds which preferably contain 0.5-60% by weight of oxyethylene groups as the hydrophilic component can also be used as emulsifiers. The hydrophobic portion of these emulsifiers can preferably be composed of polyoxypropylene and should then have a molecular weight of over 600. Mixed polymers with a total molecular weight of more than 800, which consist of 90-200% by weight of polyoxypropylene glycol and 10 to 80% by weight of polyoxyethylene glycol, are suitable emulsifiers, as is known from German Offenlegungsschrift 1,495,227. Further suitable emulsifiers are described in German Offenlegungsschriften 2,046,575 and 1,928,026. The effectiveness of the emulsifiers soluble in the organic phase can be increased by water-soluble, low molecular weight, organic compounds which contain both a hydrophilic and a hydrophobic component. Compounds of this type are in particular alcohols, organic acids, ethers, ketones, wetting agents and the like. Of course, the aforementioned emulsifiers can be used individually or in a mixture. The amount of the emulsifier or emulsifier mixture to be used is to be adjusted according to the desired degree of dispersion of the emulsion; it is preferably in a range from 0.05 to 10.0% by weight. Then usually 75-90 parts by weight of water are emulsified in 75-10 parts by weight of this polymerizable mixture. In order to distribute the water in the organic phase, customary stirrers, dissolvers or similar devices can be used.

In order to polymerize or harden the polymerisable or hardenable portions of this emulsion, catalysts and optionally accelerators can be added to the emulsion. These catalysts, such as alkali, formaldehyde, sulfoxylates, persulfates, hydrogen peroxide, sodium bisulfite or cobalt chloride, can be water-soluble. However, there is also the possibility of using catalysts or accelerators such as benzyl peroxide, lauryl peroxide, ethyl methyl ketone peroxide, cyclohexanone

peroxide, azodiisobutyronitrile, N, N-diisopropyl-p-toluidine, tertiary amines such as dimethylparatoluidine, dimethyl- or diethylaniline, and cobalt naphthenate are soluble in the polymerizable phase. In some cases it may be advantageous to use a catalyst which is soluble in the phase to be polymerized in addition to a water-soluble catalyst or accelerator. These catalytically active substances should generally be added to them in amounts of 0.1-10%, based on the total weight of the emulsion. Furthermore, this emulsion can also inhibitors, for. B. 4-ethyl pyrocatechol, 3-methyl pyrocatechol, tertiary butyl pyrocatechol, toluhydroquinone, hydroquinone, 2-, 5-di-third-butylquinone, P-benzoquinone, plasticizer, fillers and dyes .

When emulsifying the water in the polymerizable phase, the emulsion is preferably first set to a degree of dispersion which is in the range which is characteristic of the emulsion in question. The polymerizable portion of the emulsion is then expediently cured in a manner known per se with shaping and the resulting molded part is optionally dried, as is already known.

It is essential for the process of the invention and the molded parts produced according to it that the finest possible open porous foam is produced with an average cell diameter of not more than 50 μm, preferably less than 20 μm, in which the flame retardant component is dissolved or as a finely divided solid is contained in an even distribution. These flame retardants can apparently build a barrier layer with the plastic at elevated temperatures, which is resistant even at temperatures above 800 ° C and prevents the flame and thus the fire from spreading. The extraordinarily fine-porous material structure of the 35 open-pored emulsion foam usually also seems to be essential for the formation of such a stable barrier layer.

While halogen-containing organic compounds, together with antimony trioxide as a flame retardant component in emulsion foams, hardly offer any flame retardancy, even with small amounts of the inorganic substances to be used as barrier layer formers in the process according to the invention, an effect is obtained which generally exceeds the use of the same agents in non-porous plastics. 45 inorganic compounds which release water at higher temperatures, for example water glass in the form of sodium or potassium disilicate and tri-silicate, calcium sulfate, advantageously as dihydrate, silicates such as magnesium or aluminum Silicate, boron compounds such as borax, aluminum-50 minium hydroxide, asbestos or salts, which contain more or less water bound in the form of water of crystallization, which they release at higher temperatures. Another good flame retardant effect can be achieved with non-combustible inorganic substances which release carbon dioxide when exposed to flame, such as calcium carbonate, chalk and the like. These flame retardant components can be introduced into the emulsion in the form of an aqueous solution or as powdery solids.

In addition, it is possible, for example, to use compounds which split off flame-retardant gases such as nitrogen, CO2, SO2, e.g. B. sodium bicarbonate, ammonium phosphate, ammonium sulfate. However, the latter compounds should generally only be used with the preferred flame retardant components, which form a well-insulating barrier layer when the emulsion foam is exposed to flame.

Also compounds such as paraformaldehyde, urea, phosphates, dicyandiamide, phosphoric acid esters

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Pentaerytris, which inflate to flame-retardant insulation layers at higher temperatures (220-300 ° C), can be used. The insulating layer formers can, for example, also be applied to the finished molded parts as lacquers or solutions for impregnation, while the other flame retardant components to be used according to the invention are introduced as barrier layer formers into the emulsion before curing.

Even with small amounts of the aforementioned barrier-forming flame retardant components, for example 5-20% by weight, based on the emulsion, excellent flame retardancy is obtained even at high temperatures above 1000 ° C.

The flame-retardant molded parts produced by the process according to the invention usually also have the advantage that they can be easily extinguished with water and are hardly distorted under the action of high temperatures. Such resistance to the effects of fire could not have been foreseen, since the same effect can hardly be achieved with compact resins.

According to a preferred variant of the process of the invention, fibrous substances and / or light fillers, including coarser grains, are also added to the water-in-oil type emulsion to be used according to the invention. For example, plastics and foams that do not dissolve in the emulsion or that do not disintegrate due to dissolving or swelling have proven successful, in the form of the smallest, possibly expandable particles, hollow spheres, solid spheres, and fillers with possibly larger particle sizes, such as those made of polyurethanes, Melamine, urea, formaldehyde, phenol, epoxy resins, polyamides, PVC, polyvinylidene chloride, acrylonitrile, polymethacrylate, etc., or from expanded inorganic substances such as glass, perlites, vermiculites, slag, pumice. Heavy aggregates such as quartz, gravel, asbestos are also suitable. The aforementioned additional fillers or additives can significantly increase the mechanical properties, in particular the bending strength, of the molded parts produced according to the invention in the form of fibers.

It is also possible to use a wide variety of additives and fillers in combination in order to vary the density and the mechanical properties, such as compressive strength and flexural strength, of the molded parts produced according to the invention.

The fillers or additives can be used in such coarse grain sizes (e.g. 10-30 mm and more diameter) that the water-in-oil emulsion, which already contains the inorganic flame retardant components, can be filled into the spaces between the additives, this emulsion can also contain additives in fine, slippery grain (0.05-2 mm diameter).

For the implementation of the method and the desired effects, for example, the removal of the water within a short time is still important. Studies have shown that the final shrinkage level in emulsion foams is usually only reached when approx. 75-85% of the water introduced is removed.

A higher water content of the molded part consisting of emulsion foam and produced according to the invention usually impairs the good insulating effect of the porous material against heat and thus also the stability of this material at higher temperatures.

Emulsion water that remains in the product or escapes very slowly usually indicates that the water needs to diffuse out of closed cells. It is precisely this condition that generally leads to irregular a) distortion and b) severe cracking under the influence of flame. There are usually openings through which the flames penetrate.

Predominantly closed-pore material decreases

In general, hardly any moisture diffuses out of the water. In the case of open-pore emulsion foams, the residual moisture which is advantageous for flame retardancy can generally be set and maintained by taking hygroscopic substances and those which physically contain water which is released at high temperatures into consideration, taking the air humidity into account. When exposed to heat, the water vapor can escape from the open pores without building up pressure. Open-pore foams can be filled with water during a fire or when there is a risk of fire, so that additional extinguishing and fire protection effects are usually obtained. The water usually dries out quickly without damage. Impregnation with flame retardants can also be carried out.

According to the invention it is therefore necessary, for example, to adjust the structure of the material so that drying can take place without hindrance and the water is not forced to diffuse through cell walls, i.e. the open porosity must be sufficiently guaranteed. This can be done by the speed of the drying process itself, as well as by testing for the passage of liquids and gases, but also in the alternative by the rate of absorption of liquids, e.g. in the drop absorption test. For the flame-retardant molding compounds, molded parts and construction elements produced by the process, it is therefore necessary to have the lowest possible water content after drying, preferably not more than 0-5%, which usually also occurs automatically due to the air humidity.

The setting of the open porosity of the end product cured from a water-in-oil emulsion can advantageously be achieved in that the degree of dispersion of the emulsion, preferably with finely divided flame retardants, optionally using emulsifiers, the mechanical fine distribution via the stirrer, the number of turns and the stirring time the emulsion is adjusted

that the required degree of dryness is obtained in the desired time after curing. At the same time, the mechanical properties are also set, which are essentially dependent on the pore volume, the structural fineness and the ratio between open and closed cells.

The required degree of dispersion can be obtained in a simple manner by a new process by relating the viscosity of the emulsion to its stability during curing and the drainability of the cured product, as is already known.

With about six test trials, a curve can usually be determined from which the degree of dispersion can be clearly seen, in which the emulsion has to be adjusted in order to drain the finished molded part briefly after curing.

For this purpose, about six samples of the water-in-oil emulsion with increasing viscosity, which can be adjusted by increasing the number of revolutions, stirring time, temperature, but also with the emulsifiers, are cured under otherwise identical batch conditions. Of these six cured samples, the wet weight and drainage are typically determined by drying at a temperature of 23 ° C with ventilation. The method can also be shortened by determining the weight loss shortly after the hardening and after the water has been sucked off under reduced pressure. If the percentage weight loss or water loss is related to the viscosity, a curve is formed from which the most suitable viscosity is determined

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that leads to a sufficiently firm product on the one hand and a quick-drying product on the other.

The relationship between open and closed pores can usually be easily determined, as mentioned above, by the speed and amount of absorption of liquids (water, alcohol) in test specimens.

It should be taken into account that the addition of flame retardants and fillers can significantly change the behavior of the water-in-oil emulsion. An emulsion that has a sufficient drying rate or open porosity after hardening can lead to an almost closed cell system due to filler additives. The degree of dispersion should therefore be adjusted with these additives if possible

1 shows the changes in the drying speed as a function of the viscosity on the basis of a graphic representation. For example, it can be clearly seen that the properties of the cured products are predetermined with the setting of the degree of dispersion.

The values shown graphically in FIG. 1 were obtained with a water-in-oil emulsion consisting of 45 parts by weight of an unsaturated polyester casting resin and 55 parts by weight of water. During the tests, the viscosity was changed and the associated test piece was dewatered by suction. The percentage water loss determined after vacuuming is related to the viscosity before curing. The change in water loss in connection with the viscosity is related to the stability of the emulsion during curing. As can be clearly seen, the open porosity can be adjusted via the degree of dispersion, as is already known.

The degree of dispersion is usually set in a still favorable drying range between 1500-200 cP, since the mechanical values increase in this range.

The molding compositions and moldings produced by the new process usually achieve flame resistance and mechanical properties at low densities from approx. 0.15, which were not to be expected.

For example, a 4 cm thick plate produced according to the invention, which is made from an emulsion with a water content of 60%, a styrene-modified polyester resin and 34 vol.% Expanded glass (grain size 1-5 mm), has a density after drying 0.38. In comparison with a corresponding and previously known method made of expanded polystyrene and cement and a material made with polyester foam and expanded glass, the following strength values result:

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material

density

print

Bend

warmth

g / ccm strength strength guide number

kp / qcm kp / qcm

X

Polystyrene

0.3

3rd

2nd

0.1

foamed / cement

0.5

15

4th

0.15

polyester

foamed / expanded glass

0.37

32.5

-

0.06

Emulsion foam /

Expanded glass

0.37

60

30th

0.047

If the above-mentioned emulsion foam plate is directly exposed to flame with a butane burner, which produces 1600 ° C on the surface of the plate, a temperature of 140 ° C is only measured after 55 minutes on the back of the plate with a thermocouple. It can be established that the fillers used for reasons of saving not least favor the temperature conduction to the disadvantage of flame resistance.

The favorable results of the emulsion foam produced according to the invention can obviously be explained by

that due to the structural fineness of the hardened emulsion, excellent temperature insulation is achieved with the escape of water, which hardly changes even at higher temperatures. so

The slight change in the coefficient of thermal conductivity (kcal /

m • h • ° C) with increasing temperatures results from the following table:

ss

() 0C 20 ° C 6 () ° C

Emulsion foam without

Filler, density 0.3 0.047 0.048 0.049

Emulsion foam with filler

(expanded mineral), 60

Resin: filler = 1: 1,

Density 0.35 0.0475 0.0485 0.05

This shows that the change in the coefficient of thermal conductivity is generally less than that known for conventional insulating foams such as polystyrene. In order to characterize the properties under the action of flame, comparative tests are listed below, with the flame retardant components to be used being added to compact resins and emulsion foams.

As already mentioned, when carrying out the method of the invention, the proportion of open cells in the cured product is predetermined by setting the degree of dispersion and it enables, for example, 75-85% of the water introduced with the emulsion to be removed without effort in the shortest possible time. This can maintain the open cell structure apparently necessary for the flame protection of the products produced according to the invention and, in the molded part produced according to the invention, the setting of the residual water, taking into account the air humidity, addition of hygroscopic substances and such additives which contain water physically bound, to an amount of preferably between 0 and 5%, maximum 8%, based on the volume.

The advantageous residual water content generally varies depending on the density and flammability of the material and its filler content. It is advantageous if, when carrying out the process of the invention, emulsifiers and measures are taken into account which lead to open-pored foams and in US Pat. No. Re 27,444, in US Pat. No. 3,734,867 and in Belgian Patents 785,091 and 741 308 are described.

However, in these publications, for example, the measures which lead to a small amount of water remaining in the dried product are not specified. In the following investigations, based on three recipes for emulsion foams, the adjustment of the low water content in the end product is usually carried out

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made the degree of dispersion. The following table shows, for example, the composition of the formulation for the emulsion foams and, with the viscosity indicated, the value is determined which guarantees appropriate drainage and open-cell porosity of the product with the flame retardants introduced.

The composition of the samples normally only varies in the amount of water added to the emulsion, in the viscosity and in the various flame retardants tested in the fire test. The samples are prepared in a known manner: the polymerizable parts of the batch and the additive soluble therein - without accelerator - are mixed with water to form the water-in-oil emulsion. The flame retardant is optionally added to the finished water-in-oil emulsion, the water or the resin, and finally the peroxide is mixed in with the fillers. The emulsion is poured into a 7 X 7 X 3 cm polyethylene container and cured. Before the casting is removed, the wet weight is determined and the sample is dried to constant weight at 23 ° C. The residual water content is determined and the fire test is carried out. In the fire test s (see Table 2), the sample is clamped vertically and flamed at a right angle with a butane burner, which produces a temperature of 1600 ° C in its light blue flame core. The flame core of 1600 ° C is aligned with the surface of the test specimen in such a way that a temperature of approx. 1600 ° C is created on an area with a diameter of approx. 15-20 mm. On the back of the test part, the temperature is monitored with a thermocouple over a period of 5 minutes via a hole 10 mm from the flame core. In addition, the depth of the fire bowl in the center caused by the flaming is measured after the charred parts have been removed.

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Table I

Experiment no.

l

3-13

14

15

16

17th

18th

19th

resin

UPI

UP 2

UPI

X

X

X

X

X

X

80

90

80

X

X

X

X

X

X

Polymers

Monomers

MMA

Styr.

MMA

X

X

X

X

X

X

20th

10th

20th

X

X

X

X

X

X

Benzoyl peroxide paste with% by weight benzoyl peroxide

3.0

3.0

3.0

X

X

X

X

X

X

Accelerator dimethyl-p-toluidine

0.3

0.3

0.3

X

X

X

X

X

X

Inhibitors

C10

C10

C10

X

X

X

X

X

X

Emulsifier P123

Condensation product

Propylene and ethylene glycol

1.5

1.0

1.5

X

X

X

X

X

X

water

125

125

125

125

150

200

300

125

X

Stirring time in sec.

150

180

150

180

180

180

210

180

X

Emulsion temperature in ° C

25th

23

23

23

24th

24th

24th

23

X

Viscosity in cP

1500

1600

1800

2600

2800

3800

3500

1800

X

Gel. Time in minutes

12

5.5

6

5

5

6

5

5.5

6

UP = Unsaturated polyester resins

Abbreviations explained below are used in Table 1:

1. Commercial product from maleic and phthalic anhydride and propylene glycol;

Styrene content 35%, viscosity 650-100 cP at 20 ° C, acid number below 30 = UP 1

2. Commercially available polyester casting resin based on hetic acid;

Type 1110 according to DIN 14946, chlorine content 27%, acid number max. 30, styrene content 25% = UP 2

1. polymethacrylic acid methyl ester (suspension polymer composed of approx. 95% MMA and 5% acrylic acid butyl ester);

Monomers

55

Polymers

Peroxide accelerator

Inhibitor emulsifier

65

Grain size approx. 20-50 u = PM

1. styrene = st

2. Methyl methacrylate = MMA

3. Acrylonitrile = AN

4. Butyl acrylate = ASB

5. Ethylene glycol dimethacrylate = EGM

1. Benzoyl peroxide 50% = BP

1. Dimethyl-p-toluidine 50% = DMT

1. C 10 (manufacturer Oxido)

1. Pluronic 123 (manufacturer Wyan-dott): condensation product of propylene and ethylene glycol = P123

624 693

8th

Table No. 2

Fire test

Sample No.

l

2nd

3rd

4th

5

6

Back temperature,

1 '100

20th

35

48

40

30th

measured according to:

2 '-

30th

100

100

100

50

3 '-

100

-

-

-

68

4 '-

-

-

-

-

77

5 '-

-

-

80

Depth of the fire bowl after removal of the charred layer in mm x = more than 10 mm x x

X

X

X

6

Flame retardant used -

Sb.iO?

Expanded clay

Quartz 2-3 mm

Foam glass 1 mm

Perlite 10-100n

Part by weight of the flame retardant per 100 parts by weight of emulsion

1.33

13.9

286

40

22.8

Gew. D. Vers. Body wet

165

170

184

275

110

115

Gew. D. Vers. Body n. 48 pieces

124

110

135

245

85

85

Gew. D. Vers. Body dry

82

85

110

238

65

68

Residual water when performing the fire test in% by weight

4.24

3.0

8.0

5.0

4.0

4.5

Fire test

((Table 2-2.

Part)

Sample No. 7 8 9 10 11 12

Rear temperature, 1 '35 33 32 23 20 30

measured according to: 2 '57 44 43 28 25 45

3 '73 55 55 34 33 50

4 '82 65 60 43 42 58_

5 '87 75 65 62 50 66_

Depth of the fire bowl after removal of the charred layer in mm x = more than 10 mm 4.5 6 7 8 5 9

Flame retardant used

chalk

chalk

AI.Na-silicate

Na-di-silicate

Weight share d. Flame retardant on 100 parts by weight of emulsion

249

22

22

10th

22

7

Gew. D. Vers. Body wet

271

147

143

170

170

148

Gew. D. Vers. Body n. 48 pieces

250

120

115

133

135

115

Gew. D. Vers. Body dry

235

112

95

92

95

93

Residual water when performing the fire test in% by weight

3.0

16

10th

5

5.8

12th

9

624 693

Fire test

((Table 2-

-3. Part))

Test with plate 20 X 33 X 4 cm

Sample No.

13

14

15

16

17th

Min. 18

19th

Back temperature 1 '

24th

30th

30th

36

30th

10 '24

25th

measured after: 2 '

27th

37

40

55

40

20 '25

25th

3 '

34

46

55

65

45

30 '35

38

4 '

45

65

58

70

50

40 '50

49

5 '

53

100

65

75

60

50 '85

90

55 '140

140

Depth of the fire bowl after removal of the charred layer in mm x = more than 10 mm

7.5

10th

6

6

6

35

35

Flame retardant used

borax

NaDi silicate

Al.-hydrox.

Al.-hydrox.

Al.-hydrox.

Al-hydrox.

Borax NaSil. 1: 5

Al.-hydrox.

Weight share d. Flame retardant on 100 parts by weight of emulsion

10th

10th

22

20th

20th

12

15

200 vol.t.

200 vol.t.

Gew. D. Vers. Body wet

170

146

170

170

200

2400

2500

Gew. D. Vers. Body n. 48 pieces

135

82

98

65

60

1800

1750

Gew. D. Vers. Body dry

88

80

67.3

85

90

1150

1175

Residual water when performing the fire test in% by weight

1.8

3.5

1.3

5.8

5.0

5

6

The experiments carried out thereafter are intended to explain the new method and the results achieved with the new method 35 by way of example.

In test 1, the sample contains no flame retardant. The sample begins to burn immediately after being exposed to flame, and a 3.5 cm wide hole is burned through the sample after only 1 minute. The attempt will be stopped. The sample has lost three quarters of its weight.

Test 2 was made with a chlorinated commercially available polyester resin, chlorine-paraffin content 20%, and with the addition of antimony trioxide 5%. After a little over 2 minutes the sample has burned out. 45

Experiments 3-5 demonstrate the behavior of the material when using fillers with a coarser grain, namely with quartz (diameter 2-3 mm),

Expanded clay (2-3 mm diameter) and borosilicate glass (1 mm diameter). These samples are not satisfactory either, since they start to burn on the throat and after a short time the maximum temperature of 100 ° C on the back is reached.

A clear improvement is now being achieved with perlite and chalk, whereby a mixture of very fine particles, grain diameter approx. 40 n, and coarser parts up to 2 mm was used for pearlite.

Experiments 3-8 received the additives from the following points of view. It is assumed that the distribution relationships between the flame-retardant and burning substances are of importance for flame protection. The additions in the aforementioned experiments 3-8 were therefore made in volume fractions, namely two volume fractions of the filler were added to each volume fraction of the emulsion. Samples 3-5 with coarse fillers 6s start to burn immediately on the entire surface, the temperature of 100 ° C is reached on the back after a short time. The samples 6, 7 and 8 with pearlite and chalk, which are provided with finer fillers, differ significantly from this. A clearly effective flame retardant can already be determined here. The mixture of fine and coarser-particle pearlite already fulfills the conditions necessary for the implementation of the process, as does the chalk.

Experiments 9-13 demonstrate fire protection with various silicates and borax. It turns out that the temperature measured on the back increases slowly and moderately. The depth of the fire bowl is between 5 and 9 mm. A more or less solid, insulating layer spreads over the source of the fire, which, once removed, reveals that the material treated with the flame is in perfect condition. Experiments 14-17 are carried out with increasing concentration of flame retardants and increasing pore volume, and it is shown that flame retardancy does not decrease, but rather increases even at lower densities. In tests 18 and 19, the flame resistance is tested on 4 cm thick plates, which consist of an emulsion with 55% water and unsaturated polyester casting resin using a silicate mixture (test 18) and aluminum hydroxide (test 19) and expanded glass (grain diameter 20-30 mm) were manufactured. The volume ratio between the filler and the flame retardant emulsion is 1: 2.

Trial 19 has already been described in more detail in the preceding description.

In both experiments, a temperature of 140 ° C is only measured after 55-58 minutes at a distance of 4 cm from the temperature maximum of the opposite side. This maximum temperature after a time of approx. 55-58 minutes on the back is limited to the direct action of the burner on a circle with a diameter of approx. 25 mm. The temperature in the area drops rapidly to 60-70 ° C and reaches about 30 ° C at a distance of 6 cm from the source of the fire on the back. The part is up to the direct one

624 693

10th

Flame from the burner undamaged. The depth of the fire bowl is 35 mm. In experiment 19 the flame on the back came through after 60 minutes, while in experiment 18 the back remained completely undamaged.

To reduce the flammability per se, the same agents with a higher concentration can be used, although this can be restricted to certain parts or areas. In addition to additional surface impregnation, the flammability can be prevented by a higher concentration of the flame retardants in the surface or subsequent coating. You can also use water-binding desiccants, e.g. by adding small amounts of hygroscopic salts such as calcium chloride, lithium chloride, glycerin, higher alcohols, glycols, carbohydrates, cellulose, substances that are enriched with water due to air humidity. The resulting slight water accumulation affects the insulating ability of the material and the drying in general hardly or not at all. The moisture content can thus be set very precisely and a maximum can be maintained even at low average humidity levels of 25-30%.

The process according to the invention gives, for example, molded parts with a cell structure whose pore volumes are 25-85% by volume and whose pores are largely open. These molded parts are normally characterized by a content of non-combustible inorganic compounds in amounts of 5-20% by weight, based on the weight of the molded part, and a residual water content of at most 8% by volume, preferably 0-5% by volume. %, based on the total volume of the molded part. By means of appropriate shaping, all structural elements that are used in the construction industry can be produced using the method according to the invention. For example, it is possible, according to the method of the invention, to produce the moldings required for creating walls, such as wall panels, brick-like bodies of various shapes and dimensions, wall cladding elements, supports, beams, reinforcements, door and window frames, door panels and the like. Formwork, individual formwork elements, formwork blocks and supporting elements, e.g. With

Glass fibers are reinforced. According to the method of the invention, the reverse emulsions can also be used for pouring construction-related cavities or as screed compositions. The method of the invention can also be carried out if the reversed emulsions are sprayed onto rough walls or those which are provided with a carrier covering, such as, for example, fiberboard or expanded metal, and then hardened. According to the method of the invention, carriers for oil and water tanks as well as for bathtubs and similar devices can also be produced. Furthermore, it is possible to use the method of the invention to produce pipe jackets, insulating layers and entire insulating walls or molded parts.

But also furniture, furniture parts, interior fittings of apartments, such as, for example, panels, shelves, picture frames, devices for hanging curtains can be produced by the method according to the invention. The method according to the invention also gives the possibility of producing molded parts which can be used in a wide variety of areas of application for equipping large rooms as parts for industrial production, such as housings, temporary accommodation and roof coverings.

Since the molded parts of the invention produced by the process according to the invention turn out to be practically non-flammable when exposed to flame, these molded parts can also be used as so-called fire protection walls or walls and as fire protection doors.

The materials produced according to the invention also have the significant advantage that they are largely weatherproof and are not subject to decay. Due to their relatively high pore volume and their low free water content, the molded parts produced according to the invention are very light in comparison to a porous molded part, the pores of which are completely filled with water and generally do not show any after-shrinkage. Rather, the molded parts produced according to the invention can be described as extremely true to the original. Even under the extreme conditions of a fire storm, they usually retain their shape over a long period of time.

15

20th

25th

30th

35

B

1 sheet of drawings