SE192540C1

SE192540C1 -

Info

Publication number: SE192540C1
Authority: SE
Publication date: 1964-01-01

Description

Uppfinnare: E Munk, 11 G Haas och D Eissfeldt Prioritet begard feat den 30 mars 1961 (Forbundsrepubliken Tgskland) Foreliggande uppfinning avser ett forfarandie for framstallning av formstycken av en fyllmassa, som bestar av fyllmedel och ett i varme hardbart bindemedel. Som fyllmedel i kanda fyllmassor anvandas exempelvis traspan, tramj81, textilsnitscl, papperssnitsel, halmhackelse eller andra spanformiga, fiberformiga, pulverformiga eller smakorndga material. De i varme hardbara bindemedlen ha den egenskapen, att de joke bli harda vid van-hg rumstemperatur eller att de hardas sã langsamt, att de kunna forvaras exempelvis flera timmar eller dagar, sa att fyllmassor, vilka innehalla dylika bindemedel kunna fyllas I en pressform utan att darvid bli harda. Vid fyilmassans upphettning i en pressform daremot hardas bindemedlet pa mycket kort lid, I. ex. mom 'Agra minuter. I kanda fyllmassor anvandas exempelvis melaminharts, fenolharts och andra bindemedel. I sarskilt hog grad kan forfarand'et enligt uppfinningen anvandas for fyllmassor med en ringa halt bindemedel. Genom anvandning av dylika fyllmassor, vilka aven betecknas som icke expanderande pressmassor, reduceras materialkostnaden vid framstallning av formstycken. Inventors: E Munk, 11 G Haas and D Eissfeldt Priority Begard feat March 30, 1961 (Federal Republic of Germany) The present invention relates to a process for the production of moldings of a filler consisting of filler and a heat-curable binder. As fillers in known fillers, for example, rag spans, tramj81, textile cuttings, paper cuttings, straw chops or other chip-shaped, fibrous, powdery or flavored materials are used. The heat-curable binders have the property that they joke become hard at ordinary room temperatures or that they harden so slowly that they can be stored, for example, for several hours or days, so that fillers containing such binders can be filled in a mold without to thereby become hard. When the fill mass is heated in a mold, on the other hand, the binder hardens in a very short time, i.e. mom 'Agra minutes. In known fillers, for example, melamine resin, phenolic resin and other binders are used. To a particularly high degree, the process according to the invention can be used for fillers with a low content of binder. By using such filling masses, which are also referred to as non-expanding press masses, the material cost in the production of moldings is reduced.

Uppfinningen avser speciellt ett forfarande for framstallning av sadana formstycken, vilka aro forsedda med ett plastskikt. Medan fyllmassan i regel ger formstycket en mindre tilltalande yta, och dessutom ytan vid anvandning av fyllmassor med ringa bindemedelhalt kan bli grov eller porig, skall genom plastskiktet dais en slat och sluten yta erhal- Dupl. kl. 39 a7: 5/04 las och dels en yta med onskad farg, masurering eller monster. For dylika plastskikt, aven betecknas som overlay eller dekorskikt, anvandas t. ex. trafaner, som impregnerats med melaminharts eller fenolharts eller nagot annat konstharts, textilvavnader, som impregnerats med plast, folier av mest olika material, som belagts med plast, eller pappersbanor, som belagts med plast, vilka alla kunna vara enfargade eller tryckta med masurering eller dekor. The invention relates in particular to a process for the production of such moldings, which are provided with a plastic layer. While the filler generally gives the molding a less attractive surface, and in addition the surface when using fillers with a low binder content can become coarse or porous, a smooth and closed surface must be obtained through the plastic layer. at 39 a7: 5/04 read and partly a surface with desired color, masuration or monster. For such plastic layers, also referred to as overlay or decorative layers, e.g. transformers impregnated with melamine resin or phenolic resin or any other synthetic resin, textile fabrics impregnated with plastics, foils of the most diverse materials coated with plastics, or paper webs coated with plastics, all of which may be monochromatic or printed with masuration or decoration .

Vid framstallning av formstycken av en fyllmassa, vilka forsetts med ett plastskikt, kan som bekant en hogvardig, spegelglatt och porfri yta uppnas, om man anvander pressformar med en hogglanspolerad yta, om det oversta skiktet av plastskiktet innehaller tillracklig mangd plast och om formstycket pressas. under Mgt tryck i pressformen. For att 5.stadkomma dylika presstryck, ãr som bekant en motsvarande hog komprimering av fyllmassan nodvandig. Man maste har aven arbeta med forhallandevis star specifik invagning, vilket betyder, att en forhallandevis stor volym fyllmassa maste uppvagas eller uppmatas och fyllas i formarna och sammanpressas till de fardiga fornastyckenas volym. In the production of moldings of a filling mass, which are continued with a plastic layer, a well-preserved, mirror-smooth and pore-free surface can be obtained, if press molds with a high-gloss polished surface are used, if the top layer of the plastic layer contains sufficient plastic and if the molding is pressed. under Mgt pressure in the mold. In order to produce such press presses, it is known that a correspondingly high compression of the filling mass is necessary. You also have to work with relatively specific weighting, which means that a relatively large volume of filling mass must be weighed or fed and filled into the molds and compressed to the volume of the finished furnace pieces.

En stor specifik invagning innebar, att for framstallning am ett formstycke med vies volym en relativt stor mangd fyllmassa erfordras .och att salunda materialkostnaden blir hog. N grund am den stora mangd fyllmassa, som komprimeras till formstycket, erhaller detta aven hog specifik vikt. For att fram- 2— — stalla sa latta formstyeken som mojligt av en sâ liten rnangd fyllmassa som mojligt med anvandning av en sâ lag komprimering som mojligt och for att producera billiga alster sa ekonomiskt som mojligt, efterstravar man som bekant att halla den specifika invagningen sa lag som mojligt, sä att formstycket an-dock erhaller den fasthet, som motsvarar pa, frestningarna. Vid dessa kanda forfaranden har det visat sig, att antingen icke nagon hogvardig, sluten yta ails kan uppnas eller att ytart myeket ofta uppvisar s. k. oppna stallen eller porer. Sadana fel kunna redan upptackas med blotta 8gat. Dessa felaktiga stallen upptaga latt smuts under formslyekenas anvfindning, exempelvis som bordsskivor, sitsar eller dylikt, varigenom det mindervfirdiga formstycket snabbt blir mindre tilltalande. Della forsva'rar till exempel anvandning av enfargade dekorskikt, sâ att man maste valja dekorskikt med sadana monster, hos vilka felaktiga och av smuts missfargade stallen aro mindre iogonfallande. En. stor olagenhet är den stora andelen utskottsvara och den darned forbundna osakerheten vid produktionen. A large specific weighing meant that for the production of a molding with a large volume a relatively large amount of filling mass is required and that the material cost is thus high. Due to the large amount of filling mass which is compressed into the molding, it also receives a high specific gravity. In order to produce as light moldings as possible from as small a filling mass as possible using as low a compression as possible and in order to produce cheap products as economically as possible, one strives, as is well known, to maintain the specific weighting. as lawful as possible, so that the molding nevertheless acquires the firmness corresponding to the temptations. In these known procedures it has been found that either no high-density, closed surface ails can be obtained or that the surface type often has so-called open stalls or pores. Such errors can already be detected with mere 8gat. These faulty stables absorb light dirt during the use of molds, for example as table tops, seats or the like, whereby the inferior mold piece quickly becomes less attractive. Della defends, for example, the use of single-colored decorative layers, so that one must choose decorative layers with such monsters, in which faulty and dirt-discolored stables are less conspicuous. One. great inconvenience is the large proportion of committee goods and the associated uncertainty in production.

FOreliggande uppfinning avser ett forfarande for att av en fyllmassa framstalla formstycken, som aro forsedda med ett plastskikt, enligt vilket farfarande de ovan angivna ola.- genheterna vid de kanda forfarandena elimineras, utskottmaterial undvikes oeh en sin-ten, parfri yta med absolut sakerhet erhalles vid framstallningen i synnerhet Oven nar en fyllmassa med en ringa halt hindemedel anvandes och en lag invagning och lag komprimering tillampas, i syfte att astadkomma formstycken med ekonomisk materialfOrbrukfling och lag specifik vikt. The present invention relates to a process for producing moldings from a filler which are provided with a plastic layer, according to which process the above-mentioned oligomers in the known processes are eliminated, waste material is avoided and a sintered, pair-free surface with absolute certainty is obtained. in the manufacture in particular When a filler with a low content of inhibitor is used and a layer of weighing and a layer of compaction are applied, in order to provide moldings with economical material consumption and a specific weight.

Det for uppfinningen ntmarkande fir i forsta hand, att ett plastskikt am/Tides, vars gasgenomslapplighet är mindre an fyllmassans gasgenomslapplighet och att filminstone under hardningstiden ett sadant gastryck skapas i formstyckets inre i plastskiktets omrade, som ger upphov till ett specifikt uttryck pa formstyckets -yta, 'liken bilda.s av plastskiktet narmast formvaggen, vilket yttryck ligger ovanfar angtrycket fOr de flyktiga bestandsdelarna vid radande temperatur. The object of the invention is primarily that a plastic layer am / Tides, whose gas permeability is less than the gas permeability of the filling mass and that at least during the curing time such a gas pressure is created in the interior of the molding in the plastic layer area, which gives rise to a specific expression on the molding surface. The corpse is formed by the plastic layer closest to the mold wall, which surface pressure is above the angular pressure of the volatile constituents at radiating temperature.

Verkan av forfarandet enligt uppfinningen kan forklaras pa foljande salt. Vid press- ningsforloppets borjan, dvs. med tilltagande uppvarmning av fyllmassan, tillslutes pressformen mer och mer, varvid fyllmassan kom- primeras mer och mer, tills formdelarna vid fullstandigt tillsluten pressform med sina distanslister, knivkanter eller trycklister an- ligga mot varandra och fyllmassan kompri- merats till det fardiga formstyckets volym. Under den foljande presstiden kan a ena si- dan en ytterligare komprimering av fyllmassan inte figa rum genom den slutna pressformen. A andra sidan avtar den motkraft ytterligare, som av den komprimerade fyllnaassan utova.s pa formen, pa grund av materialets tilltagande upparmning, bindemedlets flytning i materialet och slutligen joke minst pa grund av det avtagande gas- och angtryeket genom de gaser och angor, som avga ur pressformen. Med detta fortskridande tryekfall i formstycket sjunker aven det specifika yttrycket pa formstyckets yta. Det har emellertid visat sig, att plastskikt alltefter sammansattning och anvand plasttyp maste pressus med ett hestamt, specifikt yttryck for att en sluten och porfri yta skall kunna erhallas. Det foreligger dad& risk, speciellt em man arbetar med lag irrvagning, att det specifika yttrycket vid formstyckets yta pa grund av tryckfallet inne i formstycket sjunker under det minimitryck, som erfordras for plastskiktet och att darigenom felaktiga ytor uppsta. Vidare innehalla fyllmassor och plastskikt alltefter sin sammansattning olika flyktiga bestandsdelar, sasom egen fuktighet, som uppsta'tt vid framstallningen eller under lagringen, reaktionsvatten, som avspjalkats vid hardningen, fri formaldehyd och andra flyktiga bestandsdelar. Om salunda trycket i pressformen sjunker under det angtryek for de flyktiga bestandsdelarna, som motsvarar den radande temperaturen, maste dessa ga Over frail den flytande fasen till angfasen. Det har nu visat sig, att orsaken till att ytorna bli poriga och icke slutna, ar att stika hos anghlasor, vilka ofta are mikroskopiskt smd on orsakats, av flyktiga bestandsdelar. The effect of the process according to the invention can be explained by the following salt. At the beginning of the pressing process, ie. with increasing heating of the filling mass, the mold is closed more and more, whereby the filling mass is compressed more and more, until the mold parts with completely closed press mold with their spacers, knife edges or pressure strips abut each other and the filling mass is compressed to the finished molding volume. During the following pressing time, on the one hand, a further compaction of the filling mass cannot take place through the closed mold. On the other hand, the counterforce further exerted by the compressed filling shaft on the mold, due to the increasing build-up of the material, the flow of the binder in the material and finally jokes at least due to the decreasing gas and vapor pressure through the gases and vapors depart from the press form. With this progressive pressure drop in the molding, the specific surface pressure on the surface of the molding also decreases. It has been found, however, that plastic layers, depending on the composition and type of plastic used, must be pressed with a horse-drawn, specific surface pressure in order to obtain a closed and pore-free surface. There is a risk, especially if working with law weighing, that the specific surface pressure at the surface of the molding due to the pressure drop inside the molding drops below the minimum pressure required for the plastic layer and that incorrect surfaces thus arise. Furthermore, fillers and plastic layers, depending on their composition, contain various volatile constituents, such as their own moisture, which has arisen during manufacture or during storage, reaction water which has been decomposed during curing, free formaldehyde and other volatile constituents. Thus, if the pressure in the mold decreases below the ang pressure of the volatile constituents corresponding to the radiating temperature, these must give over frail the liquid phase to the ang phase. It has now been found that the reason why the surfaces become porous and not closed is to stick in contact lenses, which are often microscopically smudged, by volatile constituents.

Overraskande nog har det visat sig, att yid forfarandet enligt uppfinningen uppkomsten av dylika angbubblor och darav fororsakade porer i formstyckenas yta kan undvikas genom att i farmstyckenas lure alstras ett gastryek, som ãr storre an de flyktiga bestandsdelarnas, angtryck vid radande temperatur, sa att de flyktiga bestandsdelarna icke kunna Overgâ till angfasen. Det enligt uppfinningen anvanda plastskiktet, vars gasgenomslapplighet är mindre an fyllmassans gasgenomslapplighet, verkar harvid pa liknande satt som ett relativt gastatt membran sasom barriar eller sparrskikt for gasen och tryckes av gastrycket mot pressformens vagg med ett specifikt yttryck, som ãr hogre an angtrycket, varfor angblasor icke kunna uppsta. vid plastskiktets yta. Fyllmassans gasgenomslapplighet är beroende exempelvis av arten och kornstorleken hos fyllmedlet i fyllmassan, av fyllmassans halt av bindemedel, av fyllmassans komprimeringsgrad i pressformen m. m. Den i varje enskilt fall erforderliga mindre gasgenomslappligheten hos plastskiktet kan faststallas p0 enkelt satt genom forsok. Anvandas plastskikt av en med konstharts impregnerad pappersbana eller liknande plastskikt, fir deras gasgenomslapplighet I regel mindre an gasgenomslappligheten hos fyllmassans i pressformen. Nar plastskiktet hardats., kun- — —3 na uppstaende hngblasor givetvis inte langre fororsaka porbildning. Det är ddrfor Whackligt, om gastrycket yid forfarandet enligt uppfinningen alstras atminstone under den tid, nar hardningen sker i plastskiktets omrade, och det dr icke erforderligt att aven uppratthalla gastrycket under hardningen av formstyckets, inre. Bestammande for storleken av det gastryck, som enligt uppfinningen alstras i formstyckets inre, dro inte heller tryckforhallandena i formstyckets karna, utan, tryckforhallandena vid formstyckets yta, som bildas av det mot formvaggen anliggande plastskiktet. Om salunda exempelvis vid tjockvaggiga formstycken gastrycket a-vtar i riktning frau karnan till ytan, bor i formstyckets inre alstras ett sadant gastryck, att vid formstyckets, yta racier ett specifikt yttryck, som är storre an de flyktiga bestandsdelarnas hngtryck. Surprisingly, it has been found that in the process according to the invention the appearance of such vapor bubbles and consequent pores in the surface of the moldings can be avoided by generating in the lure of the farm pieces a gas pressure greater than that of the volatile constituents, so that they the volatile constituents cannot transition to the vapor phase. The plastic layer used according to the invention, the gas permeability of which is less than the gas permeability of the filling mass, acts in a similar manner as a relatively gas-tight membrane such as barriers or barrier layers for the gas and is pressed by the gas pressure against the mold mold wall with a specific surface pressure. not be able to arise. at the surface of the plastic layer. The gas permeability of the filler depends, for example, on the nature and grain size of the filler in the filler, on the content of binder in the filler, on the degree of compression of the filler in the mold, etc. The smaller gas permeability of the plastic layer required in each case can be easily determined. Plastic layers are used from a paper web impregnated with synthetic resin or similar plastic layers, for their gas permeability As a rule less than the gas permeability of the filling mass in the mold. When the plastic layer has hardened, the rising hanging blisters can of course no longer cause pore formation. It is therefore unfortunate if the gas pressure in the process according to the invention is generated at least during the time when the curing takes place in the area of the plastic layer, and it is not necessary to also maintain the gas pressure during the curing of the interior of the molding. Determining the magnitude of the gas pressure generated according to the invention in the interior of the molding also did not draw the pressure conditions in the cores of the molding, but, the pressure conditions at the surface of the molding, which are formed by the plastic layer abutting the mold wall. If, for example, in the case of thick-walled moldings, the gas pressure decreases in the direction from the core to the surface, such a gas pressure is generated in the interior of the molding that a specific surface pressure racier at the surface of the molding is greater than the volatile constituents of the volatile constituents.

Vid kanda metoder är det ofta nodvandigt att avleda de heta angorna, som uppsta under pressningen, da i annat fall de ur pressformen uttagna fardiga formstyckena brista. Man har darfor artvant pressformar, vilka aro forsedda med oppningar, genom vilka de heta angorna kunna utstromma ur formen. Man har avert anvant dessa Oppningar for att skynda fyllmassans hardning genom tillforsel av va..rme, narmare bestamt genom periodiskt omvaxlande tillfarsel av heta gaser in i pressformens inre och avledning air de heta gaserna tillsammans med de vid fyllmassan.s upphettning bildade och frigjorda angorna En sadan omvaxlande tillf8rsel och avledning av luft kan desto lattare genomforas, ju mind-re fyllmassans komprimering är och ju star-re foljaktligen formstyckets gasgenomslapplighet ãr. For forbattrad spolverkan har man aven anvant fordelarstycken, som ph den sida air formstycket, som icke erhaller flagon yta av plastskikt, inforas i fyllmassans inre. Vid anvandning av pressformar air derma typ kan forfarandet .enligt uppfinningen genomforas pa sh satt, att pressformens oppningar tillslutas i plastskiktets omrade under hardningstiden. Forutsattning harvid är givetvis., att pressformen är tillrackligt tat och att genom fyllmassans upphettning ett tillrackligt Mgt gastryck uppstar i pressformens inre, exesu- pelvisinnesluten luft, sh att vid den yta av formstycket, vilken bildas av plastskik- let, ett sadant specifikt yttryck bildas, som är storre an angtrycket hos de flyktiga be- standsdelarna. Efter plastskiktets hardning kunna pressformens oppningar Ater oppnas for att avleda angorna ur formen och armed fOrhindra, att formstycket senare spricker. In known methods, it is often necessary to divert the hot vapors which arise during the pressing, otherwise the finished moldings removed from the pressing mold will burst. For this purpose, mold molds are provided, which are provided with openings through which the hot vapors can flow out of the mold. These openings have been used to accelerate the curing of the filling mass by supplying heat, more precisely by periodically alternating supply of hot gases into the interior of the mold and diverting the hot gases together with the vapors formed and released during heating of the filling mass. Such an alternating supply and dissipation of air can be carried out more easily, the smaller the compression of the filling mass and the consequently the gas permeability of the molding is. For improved flushing action, distributor pieces have also been used, as the side air molding, which does not receive a flat surface of plastic layer, is inserted into the interior of the filling mass. When using molds of this type, the method according to the invention can be carried out in such a way that the openings of the mold are closed in the area of the plastic layer during the curing time. The condition here is, of course, that the mold is sufficiently sealed and that by heating the filling mass a sufficient gas pressure arises in the inner, for example enclosed air, of the mold, that at the surface of the mold, which is formed by the plastic sheet, such a specific surface pressure is formed. , which is greater than the pressure of the volatile constituents. After the plastic layer has hardened, the openings of the mold can be re-opened to divert the vapors from the mold and prevent the mold from cracking later.

Enligt uppfinningen kan gastrycket vidare alstras pa sadant satt, att fyllmassan fore ifyllandet i pressformen forsattes med gasbildande och tryckalstrande arimen, t. ex. s. k. blasmedel. Dessa amnen, vilka vid, fyllmassans upphettning avge gaser och fh storm vo- lym, kunna vid lamplig dosering alstra det erforderliga gastrycket i pressformens hire. Deana atgard kan med sarskild fordel kombineras med den ovan beskrivna utforingsformat av fOrfarandet enligt uppfinningen, am fyllmassan ensam vid upphettning icke kan, alstra tillrackligt gastryck, vilket ofta dr fallet, sarskilt om pressformen icke ar tillrackligt tat. Man kan dd. avleda det gastryck, som Ostrats, av det amine, som tillsatts fyllmassan, efter hardningen av formstyckets yta och eventuellt foretaga den ovan beskrivna spolningen for att avlagsna de bildade hug,- orna ur formstycket. According to the invention, the gas pressure can be further generated in such a way that the filling mass for the filling in the mold is continued with the gas-forming and pressure-generating arm, e.g. so-called blowing agents. These substances, which, when the filling mass heats up, emit gases and fh storm volume, can, with appropriate dosing, generate the required gas pressure in the mold of the mold. These operations can be combined with particular advantage with the above-described embodiment of the method according to the invention, in which the filling mass alone on heating cannot produce sufficient gas pressure, which is often the case, especially if the mold is not sufficiently taken. One can dd. divert the gas pressure, which is ostrated, from the amine to which the filler has been added, after the hardening of the surface of the molding and, if necessary, carry out the flushing described above in order to remove the formed cuts from the molding.

Enligt ett annul kannetecken for uppfinningen alstras gastrycket pa sh salt, att komprimerad gas tillfores pressformens inre utrymme. Detta forfarande har den fordelen, att gastillforseln kan noga regleras, sh att oberoende air en mer eller mindre star °Millet lies pressformen ett gastryck av exakt onskad storlek och under onskad tidsrymd kan alstras i pressformens inre. Lampligen anvander man. fOr tillforseln av den komprimerade gasen fordelarstycken, som na in i formstyckets inre, i synnerhet, om formstycket har en storm vaggtjocklek och/eller en ogynnsam gasgenomslapplighet. Lampligen anTandes en het gas, sa att varme icke avdrages fran pressformen eller formstycket utan att hardningen paskyndas genom vdrmetillforseln. According to one annulus of the invention, the gas pressure is generated on sh salt, that compressed gas is supplied to the inner space of the mold. This method has the advantage that the gas supply can be carefully controlled, so that independently a more or less rigid Millet lies mold forms a gas pressure of exactly the desired size and for the desired period of time can be generated in the interior of the mold. Lampligen is used. for the supply of the compressed gas manifolds, which reach into the interior of the molding, in particular if the molding has a storm rock thickness and / or an unfavorable gas permeability. It is appropriate to use a hot gas so that heat is not dissipated from the mold or the molding without the hardening being accelerated by the heat supply.

Pet angivna arbetssattet kan med sarskild fOrdel anvandas aven om fOrfarandet enligt uppfinningen icke genomfores i ett steg utan I flera steg, dvs. om farmstycket framstalles i flera arbetsoperationer i stallet f6r en. Man kan I. ex. pa kant salt varmpressa fyllmassan I ett forsta arbetssteg till ett formstycke, I. ex. en. spanskiva, sa att bindemedlet hardas och sedan i ett andra arbetssteg pressa plastskiktet pa formstycket. Darvid kan det vara lampligt att yid det forsta arbetssteget inpressa kanaler i formstycket, i vilka yid det andra arbetssteget munstycken eller fordelarstyeken stracka sig, som inleda den komprime- rade gasen i formstyckets inre. Pa detta salt behover gasen endast genomtranga ett tun,- nare skikt av fyllmussan med battre gasge- nomslapplighet, och det Onskade specifika yttrycket vid formstyckets yta kan battre astadkommas. The stated method can be used with special advantage even if the method according to the invention is not carried out in one step but in several steps, ie. if the farm piece is manufactured in several work operations in the stable for one. One can I. ex. on edge salt hot press the filling mass In a first work step to a molding, I. ex. one. chipboard, so that the adhesive hardens and then in a second working step press the plastic layer on the molding. In this case, it may be expedient to press channels in the molding in the first working step, in which nozzles or the distributor pieces extend in the second working step, which initiate the compressed gas in the interior of the molding. On this salt, the gas only needs to penetrate a thin, thinner layer of the filler cap with better gas permeability, and the desired specific surface pressure at the surface of the molding can be better achieved.

Som tillsatsamnen till fyllmassan kunna vid andra modifikationer av uppfinningen sh- dana amnen anvandas, vilka sjalva eller vil- kas i varme bildade produkter genom kemisk reaktion med bindemedlet och/eller plasten I tackskiktet inleda och/eller phskynda hard- ningen. H motsvarande salt kunna amen vid tillforsel am komprimerad gas sat:lama gaser anvandas eller sadana besMndsdelar tillsattas gasen, som inleda och/eller paskynda hardningen ay bindemedlet och/eller plasten i tackskiktet. — — As additives to the filling mass, in other modifications of the invention, such substances can be used, which themselves or which in heat-formed products by chemical reaction with the binder and / or the plastic in the roofing layer initiate and / or accelerate the curing. The corresponding salt can be used in the supply of compressed gas: the gases are used or such constituents are added to the gas, which initiate and / or accelerate the curing of the binder and / or the plastic in the roof layer. - -

Claims

Patent claim:

1. A process for producing, from a filler which is a filler and a heat-curable binder, moldings which are provided with a plastic layer, characterized in that a plastic layer is used, the gas permeability of which is less than the gas permeability of the filler and that at least during the curing time such a gas pressure is created in the interior of the molding in the area of the plastic layer, which at the surface of the molding, which is formed by the plastic layer adjacent to the mold wall, produces a specific surface pressure, which is above the pressure of the volatile components at radiating temperature.

Method according to claim 1, characterized in that the gas pressure is generated by heating the filling mass, the inner space of the mold being closed at least during the hardening time of the plastic layer.

3. A method according to claim 1, characterized in that such substances are added to the filling mass, which on heating give off gases and generate a pressure.

4. A method according to claim 3, characterized in that the added substances by chemical reaction with the binder and / or the plastic in the layer initiate and / or accelerate the curing of the layer.

5. A method according to claim 1, characterized in that compressed gas is introduced into the inner space of the mold.

Method according to claim 5, characterized in that the gas contains constituents which initiate and / or accelerate the curing of the binder and / or the plastic in the layer. Listed publications: