DE2126517A1 - Hardened polymer mouldings mfre - by treating polymers with water glass - Google Patents

Abstract

Hardened mouldings are produced from polymers and aq. silicate solns. (1) by mixing polymer particles (or particulate polymer mixtures) which have an expansion of 10-5-10 cm. in >=1 of the three spatial coordinates and which contain acidic gps., with (I) and then allowing the moulding to harden. A wide variety of polymers may be used, e.g. (A) polymers contng. acidic gps. in their mol. structure such as (co)polymers of itaconic or maleic acid or anhydride, (meth)acrylic acid etc.; (B) polymer which are non-reactive per se but contain additives with acidic functions, e.g. m-phosphoric acid, benzoic acid etc. Such polymers are PF, UF, epoxides, PVC, PVAc, fluoro resins etc. Mouldings harden after convenient pot-life to form dimensionally stable articles. Used e.g. in mfre. of light structural elements.

Description

Process for the production of hardened moldings The invention relates to a process for the production of hardened moldings from polymers or polymer mixtures which chemically incorporated or groups with acidic character as a component of an admixture physically incorporated into the polymer particles contain on the one hand and aqueous silicate solutions on the other hand.

It is known to use finely divided polymers, for example in the form of hollow beads, to mix with silicate solutions and the mixtures after distilling off or after Evaporation of the water to be converted into moldings, as polymers to be used were polystyrene, polyethylene, polyvinyl chloride, formaldehyde resins and ethylene-vinyl chloride copolymers recommended (see US Pat. No. 2,797,201 and British Pat. No. 1,170 999). Such mixtures remain practically unlimited, especially in the absence of air Liquid and malleable. Only after the water has been completely distilled off can this be removed Molded bodies are produced Object of the present invention it was hardened moldings from mixtures of polymers and silicate solutions that after a certain "dripping time" (period of use, time in which the mixture is processed can be) completely solidify and thereby form a stable molded body.

The object was achieved in that polymers or polymer mixtures, the groups with acidic character incorporated chemically or as part of one of the Polymer parts physically incorporated admixture with aqueous silicate solutions were mixed.

The invention thus relates to a process for the production of hardened moldings made of polymers and aqueous silicate solutions, characterized in that that one polymer particles or particles of polymer blends, at least in one of the three spatial directions have an extension of wood 5 cm to 3 cm and the groups Incorporated with an acidic character, mixed with aqueous silicate solutions and can be obtained while shaping.

In this application, the term "incorporated" is understood to mean that the polymers or polymer mixtures incorporated groups with acidic character chemically contain. It is also understood that the polymers or polymer mixtures without built-in acidic groups, a compound with an acidic character, which is gaseous, can be liquid or solid, physically incorporated, dissolved or adsorbed may contain.

According to this process, moldings made from polymers are very easy to achieve produce without the need for complex processing equipment, as is usually the case the processing of plastics, for example thermoplastics, are common, would be required. In addition, the process also enables cross-linked, i.e. thermal un any more deformable polymers in moldings. Shape and of large dimensions to convict. In the production of the molded body is the application of heat or pressure is not absolutely necessary, but can be used without any disadvantages in To be considered. There is also no discharge in the process according to the invention of reaction heat necessary, which is an advantage over many reaction casting processes of plastics is to be valued.

The polymer particles used should be in at least one Spatially have an extension of 10 5 cm to 3 cm. When using large dimensioned particles is due to poorer flow behavior of the mixtures Processing less cheap. Polymer particles are preferred which are in at least one spatial direction have an extension of wood 5 cm to 1 cm, in turn preference is given to particles in the two other spatial directions have an extension of 10 5 cm to 5 cm.

The polymer particles can be homogeneous or inhomogeneous, i.

they can contain fillers or other additives and, for example be compact or porous or hollow eder foam particles. The polymer particles can have regular or any shape and, for example, fibers, threads, Ribbons, plates, pieces of foil, chopsticks, dumbbells, spirals, lenses, pearls or broken compact or foamed particles obtained by milling processes represent any shape. Of course, mixtures are also designed differently or sized particles can be used. The best flowability of the mixtures results from spherically shaped polymer particles, such as spheres, ellipsoids.

The polymer particles should contain groups with an acidic character. Such groups are to be understood as meaning both groups in the presence of aqueous Medium has an acidic function, for example by hydrolysis or thermal Decay reactions are able to develop, such as anhydride groups or acid halide groups 502 or CO2 also represent such groups in this sense, since they are in aqueous Medium as well as free halogen to acidic reaction give Atlas as well as groups, whose acidic character is already manifest, such as carboxyl groups, Sulfonic acid groups, sulfimide groups, carbonimide groups.

The groups with acidic character react within the pot life with the aqueous silicate solution and run through controlled precipitation of silica to harden the molding. Phenolic hydroxyl groups are in the context of the invention no groups with acidic character.

Polymer particles containing such groups with acidic character, are hereinafter referred to as "active polymer particles".

It is possible to use mixtures of active polymer particles and non-active particles of various origins synthetic polymers, fillers of a mineral or organic character, Use metal, glass, ceramic or wood.

The most favorable ratio of active to inactive particles depends on the desired pot life of the mixture according to the process and is also from the chemical and topological character of the active particles, i.e. their Ratio of weight to surface and its shape dependent, or on whether e.g. act as active groups carboxyl or sulfonic acid groups.

The most favorable ratio of active to inactive particles However, it can easily be related to the desired use and the desired Processing conditions determine by a few preliminary tests, if the additional use of inactive particles appears to be indicated at all.

The active polymer particles can be divided into basically two categories (A and B) can be distinguished. Once A in those in which the contained groups with acidic character are part of the polymer selbat and on the other hand B in those in which the contained groups with acidic character form part of a admixture incorporated into the polymer.

This admixture of B must itself be k Xn polymer, it can be an incorporated solid, a swollen, dissolved or trapped solid Act as flasigkait or a dissolved, absorbed or trapped gas. Of the Solid can have an inorganic or organic character and e.g. metaphosphoric acid, an acidic phosphate, isocyanate or benzoic acid, better citric acid, maleic acid, Fumaric acid, phthalic acid and their anhydrides or a strongly acidic bleaching earth. In addition to, for example, inorganic or organic liquids are suitable Polyphosphoric acid, toluene diisocyanate, benzoyl chloride, tosyl chloride, fatty acids from formic acid to oleic acid or acetic anhydride, if gases are hydrogen halides, Phosgene or preferably SO2 and CO2 are suitable.

These admixtures can of course also be used in a mixture with one another. They can be used to convert inactive polymers into active polymer particles transform or to achieve additional effects with active polymers, e.g. in order to influence the pot life of the mixture according to the process.

Polymers that are inherently inactive and by incorporation of the above-identified admixtures in active Polymer particles can be transferred, are in principle all non-acidic polymers be it that they are obtained from natural substances or through polymerization, polycondensation, Polyaddition, polyoxidation or other synthetic routes are accessible. For example are listed as examples: phenolic resins, melamine resins, urea resins, cellulose resins, Alkyd resins, epoxy resins, polyesters, polyethers, polyamides, polysulfones, polyimides, Polyurethane, polyethylene, polypropylene, polystyrene, poly (meth) acrylate, polybutadiene, Polyisoprene, polyvinyl chloride, polyvinyl acetate, polyacrylonitrile, polyfluoroalkenes, Silicone resins and the most varied of mixed types, whether through copolymerization or mix available.

Active polymer particles of category A in the sense of the invention are based on polymers which as such already contain groups with an acidic character. These can be obtained by, for example, monomer molecules that already exist contain the acidic groups identified above, alone or with other monomers into polymers, for example by homo- or copolymerization convicted. However, it is also possible to convert the groups with acidic character into a polymer, e.g. from the group of inactive polymers, to be introduced subsequently, including oxidation, Sulfonation or chlorosulfonation processes or saponification processes on ester or polymers containing amide groups. may be mentioned by way of example. Also through subsequent grafting of molecules with acidic groups such as acrylic acid or Maleic anhydride or vinyl sulfonic acid on preformed polymers are useful active polymers accessible.

The active polymer particles which can be used according to the process can also composed of homogeneous or heterogeneous mixtures of active and inactive polymers be or from polymer blends of the categories A and above identified B of active polymers.

The following are some examples within the meaning of the invention Category A active polymers are listed that make up the active polymer particles can be constructed without this list claiming to be complete target.

Homo- or copolymers of (meth) acrylic acid, preferably maleic acid, Maleic anhydride, maleic acid or fumaric acid half-star or ion-itaconic acid half-esters, hemiamides or other monomers containing carboxyl groups.

Homo- or copolymers of sulfonic acid or sulfimide groups containing Monomers such as vinyl sulfonic acid or (meth) acryloyl taurine. Homo- or copolymers of other monomers with acidic groups or groups that interact with water to generate react to an acidic reaction such as maleimide, methacrylic anhydride, (meth) acrylic chloride.

Some of the most common copolymerization components are exemplary named: olefins such as ethylene, butadiene; Vinyl aromatics such as styrene, vinyl toluene, methyl styrene; Vinyl halides such as vinyl chloride; Vinylidene chloride; Vinyl ethers and esters such as vinyl acetate, -propionate; (Meth) acrylonitrile; Esters of (meth) acrylic acid such as methyl methacrylate, Ethyl acrylate, butyl acrylate, oxypropyl methacrylate, (meth) acrylamides; Vinyl amides and like that.

Further active polymers of group A are graft polymers of the monomers with acidic character on a wide variety of polymeric substrates such as cellulose, Polyamide, polyethylene, polyvinyl chloride, rubber and graft products of maleic anhydride on rubber, graft polymers of (meth) acrylic acid on polyethylene or polyamides or cellulose and sulfonation products of crosslinked or uncrosslinked polystyrene, Phenolic resin, containing saponification products of fumaric or acrylic esters incorporated Polymers, reaction products of polymers containing hydroxyl groups with anhydrides such as phthalic or maleic anhydride.

The active or inactive polymers are prepared according to known methods.

Particularly suitable active polymer particles are based on carboxyl groups Obtained polymers, for example based on copolymers of acrylic acid or male and half esters with styrene, vinyl chloride, ethylene, isobutylene, butadiene, or (Meth) acrylates, by bulk polymerization processes, bead polymerization, Emulsion polymerization and possibly

subsequent crushing.

The content of groups with acidic character in the polymer particles can between 0.5 and 75% by weight, preferably between 3 and 50% by weight. Too little Acid group contents lead to incomplete or too slow gelation.

The active polymer particles can optionally be mixed with inactive material be used in dry or moist form by using them with predominantly mixed aqueous silicate solutions and allowed to solidify the mixture while shaping.

The aqueous silicate solution is preferably sodium or potassium silicates, known as water glass. The highest The concentration of these silicate solutions, which is permissible according to the procedure, is given the viscosity-related processability of such solutions, d. H. she is not rigidly defined, but is expediently not significantly above 55% by weight lie. The dilution of the silicate solution is quite possible and will only be limited by the fact that if the dilution is too high, the resulting shaped bodies have a often have unsatisfactory strength. It is advisable not to under-dilute a solids content of 5% by weight.

Preferably we will be techn «. soda water glass with a solids content of approx. 10 - 40% by weight are used.

A suitable diluent is water, but aqueous ones can also be used Solutions e.g. of water-soluble polymers or aqueous polymer latexes or polymer dispersions e.g.

of mono- or copolymers of ethylene, vinyl acetate, vinyl chloride, Find styrene, acrylonitrile, ethyl or butyl acrylate use.

According to the process, the polymer particles are optionally with the addition of Diluents such as water and possibly other additives such as emulsifiers, foam stabilizing agents, wetting agents, thickening agents, lubricants, possibly flammability-reducing additives such as antimony, phosphorus or halogen compounds and other fillers or dyes or possibly also propellants with the aqueous Mixing the silicate solution.

In this case, all polymer particles should preferably have at least the Be wetted with the silicate solution, it is better if the polymer particles are wetted and the spaces between the polymer particles with the silicate solution at least are partially filled. In the resulting structure of the mixture, the Polymerizatteilchen touch each other or through a layer of the silicate solution be at least partially separated from each other. There can also be gas bubbles between the polymer particles, for example when a gas is incorporated during the mixing process will.

However, depending on the shape of the polymer particles used and Depending on their specific weight and the desired properties of the mixture both for wetting and for embedding the polymer particles are very different Weight or volume ratios of silicate solution to solid are used need to meet the minimum conditions is only a guideline Specification of these volume ratios makes sense.

The volume ratio of silicate solution to the water-soluble polymers or may contain aqueous polymer latices or polymer dispersions, to form a solid the mixture should be between 5: 1 and 0.05: 1, preferably between 3: 1 and 0.1: 1.

The mixture of the active polymer particles with the silicate solution, if necessary in connection with other additives, can be continuous or discontinuous be carried out at room temperature or at a reduced or increased temperature, for example in agitators, kneaders or screw machines.

In general, the more silicate solution, the lower the viscosity of the mixture it contains in terms of polymer particles.

The processing equipment must also be selected accordingly. Man Once the mixture has been produced, it can be poured into moldings, for example panels, they can be poured into open or closed, heated or unheated molds, injection molding or pressing or making them directly in the molds.

The pot life of the mixtures, i.e. the time within which a Once a mixture has been produced, it can still be deformed without difficulty or loss of quality can be set in very different ways. So by increasing the pot life the amount of silicate solution or by diluting the silicate solution and adding it of additives which are not active in the sense of the process or the use of low active polymer particles; i.e. those particles that have either few groups with acidic character incorporated or included in those due to their surface properties or dimensioning the groups with acidic character take effect only slowly can, prolonged temperature increase or the choice of highly active polymer particles. i.e. those particles that take the place of the less active anhydride or carboxylic acid groups, e.g. containing the very active sulfonic acid groups or the groups with acidic character incorporated in large quantity or due to their surface properties or dimensions, these groups have an acidic character Contained in a particularly accessible form, leads to shortened pot life.

The same as for the pot life also applies to the times that pass, until the mixture, which has been brought into a mold, has solidified to such an extent that it can be removed from the mold can be extracted, i.e.

for the demolding times.

Pot and demolding times can range from a few seconds to several Hours lie.

The moldings obtainable in this way can be of almost any size and can be used in the moist or dried state, e.g. as Vessels, as structural elements, as dia- ming and insulating materials that can be largely influenced Heat resistance, as screed or construction elements of various kinds, as filter media or absorption material, for coating metals, stones or wood and textiles, for the production of sandwich elements. You can painted, coated, flocked or metallized and are in connection with wood, Metals, minerals, plaster of paris, concrete, plastics, glasses, etc. can be used.

In addition to paper, the following materials are suitable for making the molds Cardboard, wood or metals, plaster of paris, ceramics, concrete that have been surface treated, e.g. can be lacquered or laminated or hydrophobized, including silicones, rubbers, and other plastics or casting resins. In the manufacture of sandwich elements the mold material can remain on the molded body even after it has solidified. the Incorporation of reinforcement elements such as wire, wood, fabrics or fibers is also possible possible.

In the following, the method is explained by way of example, the specified Parts and percentages relate to weight, unless otherwise stated is.

Example 1: 100 parts of a copolymer of 40 parts of acrylic acid and 10 parts of acrylonitrile and 50 parts of styrene as grist with an average grain diameter from 1 mm are intensively stirred with 100 parts of 20% sodium or potassium water glass. This mixture is brought into a cup shape and solidifies there after pouring after about 6 minutes to a solid block. This block can after 30 minutes of the Form and used as such. There is drying in the circulating air cabinet easily possible (500C) and leads to a porous material with a density of approx.

0.7 g / cm3, which is used as a lightweight construction material, e.g. for filling cavities suitable is.

Example 2: A polystyrene bead polymer with an average bead diameter 1.2 mm is treated with SO2 below 3 atmospheres until there is approx. 3% by weight of SO2 recorded (solved). These pearls, which still smell faintly of SO2, become with 30% sodium silicate solution (technical water glass) poured over it and the excess Water glass thrown off. About 30% of the material thus obtained consists of the Silicate solution. Now you fill the beads sticking together in a plate shape, presses them together with about 1 atm, the material after about 50 minutes has solidified to such an extent that the mold can be opened. One lets over a. 15 hours stand and can then dry the plate if necessary, whereby a porous he Shaped body is obtained, which, however, has little resistance to mechanical stress is. Much more solid moldings are obtained when using polystyrene beads medium diameters below 0.5 mm are used.

In the same way one can proceed by instead of the massive Polystyrene beads foamed polystyrene beads with S02 using any method treated and used accordingly.

Example 3: 100 parts of a grain size of approx. 1 mm in diameter ground, crosslinked and sulfonated styrene-divinylbenzene copolymers (content 1%) and 100 parts of a phenol-formaldehyde resin brought to the same grain size (inactive component), obtained by condensation of phenol and formaldehyde in Presence of HCl, are mixed and poured into a beaker mold. Then there 100 parts of a 20% tech. Add water glass solution, stir briefly and freezes in the form. Gelling has occurred after approx. 2 minutes. The molding can then be dried if necessary and before or after by cutting Machining can be further deformed.

Example 4: Granulated polyethylene is treated with a medium Grain diameter of approx. 1.5 mm at approx. 600C with excess acetic anhydride. After about 10 hours, the polyethylene is sucked off and briefly placed in the circulating air cabinet 45 0C dried. The polyethylene powder pretreated in this way contains, by determining the solids content determined, approx. 5% by weight acetic anhydride. This powder is now with techn.

Water glass solution (40% in) and the excess silicate solution centrifuged, so that a dough-like mass with a content of silicate solution of approx. 50% by weight results. This is rammed into a hollow mold, where it is after has solidified for about 1 hour. After drying, a block with a density remains of approx. 0.6 g / cm3.

Example 5: One by copolymerization of ethylene and acrylic acid available ethylene copolymer with a built-in acrylic acid content of 25 Gew.-96 is spun from the melt into fibers. A fiber fleece is made from these fibers manufactured.

This fleece is with techn. 40% water glass solution soaked and squeezed off to a content of 50 wt .-% of silicate solution. Treated like that After 15 minutes, the flow begins to gel into an increasingly stiff material. After drying, a stiff piece of material results which, in contrast to the original fleece can be heated to 1500C without changing its shape changed significantly. The same ethylene-acrylic acid copolymer can also be in the form a powder ground to grain sizes below 1 mm with the same weight Stirred in 25 “soda water glass, poured into molds and there after approx. 30 min. gelled at room temperature. The blockware available in this way can Can be used when moist to keep plants fresh by leaving out the material e.g. manufactures transport boxes.

Example 6: Treating the ethylene-acrylic acid copolymer with Acetic anhydride at 600C, the carboxyl groups are converted into anhydride groups. The powder treated and dried in this way is then processed as above. Here, similar shaped bodies are obtained, but with the difference that the time it takes to gel is lengthened about three times.

Example 7: The greater inertia of the anhydride groups brings sometimes due to the resulting longer pot life Processing advantages. For example, when using equimolar styrene maleic anhydride copolymer. Such a powder, ground to mean grain sizes of approx. 0.3 mm, can be used with the same weight of a 40 - 5, 'own soda or. Potash water glass solution are mixed well and then forms a pourable and sprayable mixture that over Can still be processed for 30 to 70 minutes and then gels. To this In this way, large moldings can be produced without difficulty, which after approx. 2 hours can be demolded.

Example 8: 100 parts of the styrene-maleic anhydride copolymer used above are mixed with 300 parts of PVC powder and then with 300 parts of a 15figen techn. Soda water glass solution mixed. The mixture thus obtained is injected into a hollow mold and solidifies there in 45 minutes.

Example 9: 100 parts of high-pressure polyethylene are mixed with 100 parts of isobutylene-maleic anhydride copolymer (equimolar) kneaded at about 150. This mixture is reduced to a grain size Grind 1 mm. A mixture of this powder with 200 parts of the above waterglass solution begins to gel at room temperature after 65 minutes, at 60 ° C the gelation begins after just 5 minutes. A mixture produced in the same way behaves analogously from equal parts of polystyrene and styrene-maleic anhydride copolymer.

Example 10: 100 parts of an equimolar copolymer of styrene and cyclohexyl maleic acid half-ester in the form of pearls with an average diameter of 0.8 mm are used in the kneader with 150 Share 40% 1ges of soda water glass kneaded into a plastic dough.

This dough is pressed into a plate shape, which is approx.

0.4 mm thick cardboard is lined. After 5 minutes the mass is solidifies and can be demolded and dried.

A sandwich panel laminated with cardboard is obtained, which, if necessary, can be replaced by can be used as a building material after drying.

You can proceed in the same way using 20 or 10% water glass solution, in this case the times are doubled or tripled until gelling.

Likewise, you can double the amount of water glass solution, whereby the pot life increases and the strength of the mixture increases leaves.

One can proceed in the same way using the same Polymerisates, the beads of which with a mixture of equal parts of methylene chloride and Petroleum ether swollen for 15 hours and then a 5 minute heat treatment at 1800C in a circulating air cabinet, where they foam and densify between 0.1 and 0.6.

The moldings obtained with this material have after drying Densities below 0.8 g / cm³.

You can also do the same thing by adding 150 parts a mixture of equal amounts by weight of soda waterglass (40% in) and a 40% strength Latex of a copolymer (mean particle size 10 5 cm) from 80 parts of vinyl acetate and 20 parts of ethylene are used and mixed with the active copolymer. The so available moldings are more abrasion-resistant.

Example 11: 100 parts of an approximately equimolar styrene-maleic acid cyclohexyl half ester Copolymers with an average grain diameter of 0.4 mm are with 200C 200 parts 40% Soda water glass solution stirred. The mixture is flowable for approx. 7 minutes. It will turn into a cup shape in the 7th minute filled in and solidifies there within 2-5 minutes, then in principle be demolded. After drying, the molded body obtained has a density of approx. 0.8 g / cm³ and can, if necessary, be machined to remove tension. Choosing a grain diameter of approx. 0.9 mm, the pot life of the mixture is approx. 16 minutes. Do you work with a Amount of 300 parts of 40% sodium water glass, so is also a pot life of given for about 15 minutes.

Example 12: 0.5 mm thick press plates of the type used in Example 11 Polymerisates are broken and a fraction with maximum edge length between 3 and 8 mm sieved.

100 parts of this platelet fraction are mixed with 150 parts of soda waterglass stirred and placed in a horizontally arranged plate form with a thickness of 10 mm with shaking filled. After approx. 20 minutes at 35 ° C. it can be demolded.

It is advisable to dry the plate between two wire screens to prevent warping and is given a translucent sheet material, which can be used for covering purposes or decorations. In the same way can the procedure is to use fibrous rather than platelet-shaped (fused fibers, Diameter less than 0.2 mm, length 5 to 15 mm) particles of the polymer used.

Example 13: 100 parts of the polymer powder used in Example 11 30 parts of So203 and 100 parts of polyvinyl chloride powder are mixed with 300 parts of 30% strength Soda water glass solution stirred.

The mixture is flowable for approx. 12 minutes (200C) and is within During this time they are poured into a cup form where they are removed from the mold after 30 minutes can. After drying is machining the material obtained further deformable and has self-extinguishing properties that make it suitable for use in the construction sector, e.g. for cladding.

Claims (6)

Patent claims: 1. Process for the production of hardened moldings from polymers and aqueous silicate solutions, characterized in that one polymer particles or Particles of polymer mixtures that are in at least one of the three spatial directions have an extension of 10 5 cm to 3 cm and incorporate the groups with acidic character contain, mixed with aqueous silicate solutions and harden while shaping leaves. 2. The method according to claim 1, characterized in that the polymer particles in one spatial direction an extension of 10 5 cm to 1 cm and in the other two Spatial directions have an extension of 10 5 to 5 cm. 3. The method according to claim 1 and 2, characterized in that as Groups of acidic character are used by carboxyl groups. 4. The method according to claim 1 to 3, characterized in that carboxyl groups containing polymers are used as polymer particles 5. The method according to claim 1 and 2, characterized in that it is incorporated into the polymer particles as an admixture is, SO2, CO2, a carboxylic acid or a carboxylic acid anhydride can be selected. 6. The method according to claim 1 to 5, characterized in that as Silicate solution technical water glass is used.