DK157178B - PROCEDURE FOR DIRECTLY JOINING A TRANSFERABLE POLYESTER LAYER IN THE MAIN PROCEDURE WITH A DRAWING BASE - Google Patents

Description

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Opfindelsen angâr en fremgangsmâde af den i krav l's indledning angivne art.The invention relates to a method of the kind set forth in claim 1.

En pâ denne mâde fremstillet beholderbund er egnet til at anvendes til levnedsmidler og lignende. Den har et 5 plastlag pâ i det mindste den ene overflade, sædvanlig- vis den overste overflade, og kan uden at beskadiges udsættes for temperaturer op til ca. 204°C i et kort tidsrum, nâr den er tom, og i sâ lang tid soin 45 minut-ter, nâr den indeholder levnedssmidler eller andre stof-10 fer, soin fra begyndelsen har stuetemperatur eller lavere temperatur.A container bottom made in this way is suitable for use in foodstuffs and the like. It has a plastic layer on at least one surface, usually the upper surface, and can be exposed to temperatures up to approx. 204 ° C for a short period of time when empty, and for as long as 45 minutes when containing foodstuffs or other substances, initially from room temperature or lower temperature.

Det har længe været kendt, at forskellige termoplastma-terialer, som omfatter polyestere, kan sammenfojes ved hjælp af varme og tryk med et praeformet og konturformet 15 legeme, som er fremstillet af fibermassemateriale. Dette frembringer en attraktiv og meget fugtbevarende be-holder, som er anvendelig som tallerken, skàl eller lignende til levnedsmiddelopbevaring. Disse kendte pro-dukter er imidlertid ikke egnet til brug som ovnfaste 20 beholdere, der udsættes for hoje temperaturer i lang tid, blandt andet fordi plastbeklædningen enten smelter eller krymper og losner sig fra den formede fibermasse-bund, nâr beklædningen udsættes for hoje temperaturer.It has long been known that various thermoplastic materials comprising polyesters can be joined together by heat and pressure with a preformed and contoured body made of fibrous material. This produces an attractive and very moisture-retaining container which is useful as a plate, bowl or the like for food storage. However, these known products are not suitable for use as oven proof containers which are exposed to high temperatures for a long time, partly because the plastic coating either melts or shrinks and detaches from the shaped fibrous pulp floor when the coating is exposed to high temperatures.

Desuden udviser fibermassen en betydelig uonsket brun-25 farvning eller endda direkte forkulning, nâr den udsættes for sâdanne temperaturer i lang tid. Repræsentative eksempler pâ sâdanne kendte beholdere fremgâr af det folgende.In addition, the pulp exhibits considerable undesired brownish staining or even direct charring when exposed to such temperatures for a long time. Representative examples of such known containers are given in the following.

Fra beskrivelsen til USA-patent nr. 2 590 221 kendes 30 en fremgangsmâde til at smelte eller binde en film af termoplastmateriale, f.eks. polyethylen, sammen med et formgivet legeme af produktmasse, ved at man opvarmer overfladen pâ det termoplastiske materiale, som skalFrom the disclosure of U.S. Patent No. 2,590,221, a method of melting or bonding a film of thermoplastic material is known, e.g. polyethylene, together with a shaped body of product mass, by heating the surface of the thermoplastic material to be

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2 forbindes med massen, til smeltepunktet, medens den anden side holdes ved en temperatur, som er under smel-tepunktet.2 is connected to the mass, to the melting point, while the other side is maintained at a temperature below the melting point.

Fra beskrivelsen til USA-patent nr. 3 616 197 kendes 5 en fremgangsmâde til at klæbe en beklædning af polypro-pylenfolie med en konturformet produktmasse ved hjælp af et mellemliggende lag klæbestof, f.eks. pigmenteret polyamidsværte eller en pigmenteret harpiksemulsion.From the disclosure of U.S. Patent No. 3,616,197, a method of adhering a polypropylene film coating to a contoured product mass is known by means of an intermediate layer of adhesive, e.g. pigmented polyamide ink or a pigmented resin emulsion.

Fra beskrivelsen til ÜSA-patent nr. 3 657 044 kendes 10 en fremgangsmâde til at binde en film af termoplastma-teriale, som indeholder polyester, til et formgivet masselegeme ved brug af overtryk til at presse termo-plastmaterialet imod stobeformen.From the specification of USA patent No. 3,657,044, 10 is a method of bonding a film of thermoplastic material containing polyester to a molded pulp body by using overpressure to press the thermoplastic material against the mold.

Fra beskrivelsen til USA-patent nr. 3 697 369 kendes 15 en fremgangsmâde til at smelte eller binde en beklædning af polypropylenfilm til en formgivet massetaller-ken ved hjælp af et mellemliggende lag af polethylen, som sikrer bindingen med den formgivne masse.From the disclosure of U.S. Patent No. 3,697,369, a method of melting or bonding a coating of polypropylene film to a shaped pulp plate is known by means of an intermediate layer of polyethylene which ensures bonding with the molded pulp.

Fra beskrivelsen til sydafrikansk patent nr. 73/2988 20 kendes en fremgangsmâde til at binde et laminat af po-lypropylen og polyethylen, som i forvejen er ekstrude-ret sammen, til et formgivet masselegeme.From the specification of South African Patent No. 73/2988 20, a method of bonding a laminate of polypropylene and polyethylene, which is already extruded together, is known to a shaped pulp body.

Det-har fornylig vist sig, at ovnfaste beholdere, som er egnet til brug ved genopvarmning og/eller yderlige-25 re tilberedning af fodevarer i mikrobolgeovne og kon-ventionelle ovne kan fremstilles ud fra en plade af karton", som er forsynet med et overtræk af i hovedsa-gen amorft polyethylenterephthalat, som er sammenfojet ved sit eget materiale til i det mindste en overflade 30 deraf. Disse fodevarebeholdere har imidlertid mange ulemper, f.eks. er presformningen eller foldningen og 3It has recently been found that oven-proof containers suitable for use in reheating and / or further preparing food in microwave ovens and conventional ovens can be made from a board of cardboard "which is provided with a coatings of generally amorphous polyethylene terephthalate which are joined by their own material to at least one surface 30. However, these food containers have many disadvantages, for example, the molding or folding and 3

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klæbningen af beholderen af det plane ark dyr, og der er risiko for, at belægningen vil sprænges ved bukke-og foldelinierne. Sâdanne beholdere er sædvanligvis hverken sâ stærke eller sâ attraktive som formede be-5 holdere. Desuden har den presformede eller opfoldede beholder nodvendigvis plisséer eller folder og/eller hjorneâbninger, som er helt uacceptable ved visse ar-ter beholdere, f.eks. tebolle-bageforme, og de udeluk-ker hermetisk lukning ved omhylning med plast. Repræ-10 sentative eksempler pâ sâdanne kendte beholdere er fol- gende:the adhesive of the container of the planar sheet of animal, and there is a risk that the coating will burst at the bending and folding lines. Such containers are usually neither as strong nor as attractive as shaped containers. In addition, the preshaped or folded container necessarily has pleated or folds and / or corner openings which are completely unacceptable in certain types of containers, e.g. teaspoon baking molds, and they exclude hermetic closure by wrapping with plastic. Representative examples of such known containers are as follows:

Fra beskrivelsen til USA-patent nr. 3 924 013 kendes fremstillingen af en ovnfast fodevarebeholder af et laminat, som indeholder karton, som ikke brunes, med 15 en belægning af i det væsentlige amorft polyethylen-terephthalat, som er ekstruderet som en varm harpiks direkte derpâ og bundet dertil ved hjælp af sin egen substans.From the disclosure of U.S. Patent No. 3,924,013, the manufacture of a furnace-resistant food container of a laminate containing non-brown cardboard is known with a coating of substantially amorphous polyethylene terephthalate extruded as a hot resin directly thereto and bound thereto by its own substance.

Fra beskrivelsen til USA-patent nr. 4 147 836 kendes 20 fremstillingen af en ovnfast fodevarebeholder af et laminat, som indeholder karton, som ved en procès, som omfatter en corona-udladning til kartonen, er belagt med polyethylenterephthalat, idet det bemaerkes, at sidst-nævnte stofs krystallisation ikke væsentlig pâvirker 25 belægningens klæbning til kartonen.From the specification of U.S. Patent No. 4,147,836, it is known to produce an ovenproof food container of a laminate containing carton which, in a process comprising a corona discharge to the carton, is coated with polyethylene terephthalate, noting that the crystallization of the latter substance does not substantially affect the adhesion of the coating to the carton.

Man har sâlede endnu ikke været i stand til at tilveje-bringe en billig éngangsbeholder, som er formgivet i tre dimensioner uden plisséer eller folder, og som blandt andet er i stand til at indeholde fodevarer, som udsæt-30 tes for hoje temperaturer i lang tid enten i en mikro-bolgeovn eller en konventionel ovn, uden at plastbelæg-ningen smelter eller krymper og losner sig fra det form-givne underlag, uden væsentlig uonsket bruning af bun- 4Soldings have not yet been able to provide a cheap disposable container, which is designed in three dimensions without pleated or folds, and which is capable, among other things, of containing food products which are exposed to high temperatures for a long time. time either in a microwave oven or a conventional oven, without the plastic coating melting or shrinking and detaching from the molded substrate, without significant undesired browning of the bottom.

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den og uden nogen skadelig virkning pâ beholderen eller fodevarerne.it and without any detrimental effect on the container or foodstuffs.

Dette opnâs ved den indledningvis angivne fremgangsmâde, der ifolge opfindelsen er ejendommelig ved det i krav l's kendetegnende del angivne.This is achieved by the method set out in the introduction, which according to the invention is characterized by the characteristic part of claim 1.

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De produkter, som opnâs ved fremgangsmâden ifolge opfindelsen, udgores af en præformet konturformet bund, som er formet af fibermasse og med en beklædning, som er direkte forbundet med i det mindste en konturformet del pâ i det mindste den ene side af bunden. Beklædnin-10 gen bestâr i det væsentlige af polyethylenterephthalat, som ikke varmekrymper eller skilles fra den konturfor-mede bund, hvis den udsættes for en temperatur pâ ca.The products obtained by the method according to the invention are formed by a preformed contour-shaped bottom, which is formed of fibrous pulp and with a coating directly connected to at least one contour-shaped part on at least one side of the bottom. The coating consists essentially of polyethylene terephthalate which does not shrink or separate from the contoured bottom if exposed to a temperature of approx.

204°C.204 ° C.

Opfindelsen skal i det folgende nærmere beskrives med 15 henvisning til tegningen, hvorpâ: fig. 1 er et perspektivisk billede af en relativ enkel og fladt formgivet serveringsbeholder fremstillet ifolge opfindelsen, fig. 2 er et perspektivisk billede af en relativ kom-20 pliceret og dybt udformet tebolle-bageform fremstillet ifolge opfindelsen, fig. 3 er et snit gennem en del af et antal représentative tomme beholdere, som er stablet inden i hinanden i en stabel til transport og oplagring, 25 fig. 4 er et snitbillede i storre mâlestok og med stærkt overdrevet mâlestoksforhold af tydelighedsgrunde og viser et formgivet massegrundlag med en polyesterbeklæd-ning, som ved sin egen substans er bundet til den over-30 ste overflade, og 5The invention will now be described in more detail with reference to the drawing, in which: FIG. 1 is a perspective view of a relatively simple and flat shaped serving container made in accordance with the invention; FIG. Figure 2 is a perspective view of a relatively complicated and deeply formed tea bowl baking mold made in accordance with the invention; 3 is a section through a portion of a number of representative empty containers stacked within one another in a stack for transport and storage; FIG. 4 is a sectional view on a larger scale and with a greatly exaggerated scale ratio for reasons of clarity and shows a shaped mass basis with a polyester lining bonded to the upper surface by its own substance, and 5

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fig. 5 er et stærkt skematisk tværsnitsbillede, som igen i overdrevet mâlestok viser de væsentlige elementer ved apparatet til ud0vel-se af fremgangsmâden if0lge opfindelsen til sammenklæbning af det·præ-formede grundlag og filmen.FIG. 5 is a highly schematic cross-sectional view, which again shows, in exaggerated scale, the essential elements of the apparatus for selecting the method of the invention for bonding the preformed base and the film.

5 Opfindelsen beskrives detaljeret ved f0rst at beskrive det præ-formede formgivne massegrundlag, for det aridet poly-ethylenterephthalatfilmen, for det tredje fremgangsmâden til at binde filmen til grundlaget, og for det fjerde det polyesterbeklædte stobte masseprodukt, som opnâs derved.The invention is described in detail by first describing the preformed molded pulp base, for the arid polyethylene terephthalate film, the third method of bonding the film to the base, and fourthly the polyester coated pulped pulp product obtained thereby.

10 For det forste bestemmer det præ-formede massegrundlag formen og storrelsen af produktet, som dimensioneres ud fra den anvendelse, som tilsigtes med produktet. Grundlaget kan opnâs ved én eller flere af de velkendte former for massestobeteknik.10 First, the preformed mass basis determines the shape and size of the product, which is dimensioned based on the application intended for the product. The basis may be obtained by one or more of the well known forms of mass casting technique.

15 Til fremstilling af produkter med hoj kvalitet, f.eks. ovn-faste beholdere til at fremme salget af fodevareprodukter, opnâs det stobte massegrundlag ved npræcisionsformningsM processen. Præcisionsst0bte masseemner opnâs ved at forme fibermasse af en vandig opslemning, som anbringes pâ en 20 filterdækket âben sugeform til en i det væsentlige færdig form og dernæst terre den fugtige præ-form under kraftigt tryk, som pâferes med et par opvarmede stâlforme. Dette kan f.eks. gérés med det fra USA patent nr. 2 183 869 kendte apparat og de derfra kendte fremgangsmâder. Præci- 25 sionsformede fibermasseemner har stor massefylde, er hârde og træagtige med en yderst glat, varmglattet overfladekva-litet. Sâdanne præcisionsstebte fibermasseemner har været kendt og solgt i form af éngangstallerkener, skâle og lig-nende under varemærket "Chinet".15 For the manufacture of high quality products, e.g. oven-solid containers to promote the sale of food products, the solid mass basis is obtained by the precision forming process. Precision molded pulp blanks are obtained by forming fibrous pulp of an aqueous slurry which is applied to a filter-covered open suction mold to a substantially finished mold and then terrains the moist preform under high pressure applied with a pair of heated steel molds. This can be done, for example. is made by the apparatus known from United States Patent No. 2,183,869 and the methods known therefrom. Precision shaped fiber pulp blanks have a high density, are hard and woody with an extremely smooth, hot-smooth surface quality. Such precision cast fiber pulp blanks have been known and sold in the form of disposable plates, bowls and the like under the trademark "Chinet".

30 Foruden fibermassegrundproduktet, som blev frembragt ved præcisionsformeprocessen, kan stebte masseemner fremstillet i overensstemmelse med den kendte "friterrings" eller "âben-t0rrings"-fremgangsmâde tilsvarende benyttes ifelge opfindelsen. Frit0rringsprocessen betyder formning af fibermasse 6In addition to the fiber pulp base product produced by the precision molding process, molded pulp blanks made in accordance with the known "deep fryer" or "open-dry" method can similarly be used in accordance with the invention. The drying process means forming fiber pulp 6

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ud fra en vandig opslemning pâ en skærm-dækket âben suge-fom, som i det væsentlige giver emnet sin endelige form, og derefter terres det fugtige og endnu ikke færdigformede emne i et frit rum, f.eks. pâ et transportbând og fores 5 langsomt gennem en opvarmet torreovn. Sâdanne formede masse-emner er karakteriseret ved en ikke-kompakt konsistens, elastisk blodhed og en uregelmæssig fiberagtig fomemmelse ved beroring og udseende. Hvis der anvendes et friterret formet fibermassegrundlag ved fremgangsmâden ifelge opfin-10 delsen,, kræver den ru, fibrose overflade, at filmen ved bindingsprocessen presses mod fibermassegrundlagets overflade ved en temperatur og/eller et tryk, der er noget mindre, for at sikre, at filmen stadig har tilstrækkelig styrke, sâledes at den ikke punkteres af fibermassegrund-15 lagets upressede fiberoverflade.from an aqueous slurry on a screen-covered open suction chamber, which essentially gives the workpiece its final shape, and then the moist and not yet finished workpiece is tarred in a free space, e.g. on a conveyor belt and passed slowly through a heated drying oven. Such shaped mass blanks are characterized by a non-compact consistency, elastic bloodiness, and an irregular fibrous appearance by touch and appearance. If a deep-fat fibrous pulp base is used in the method of the invention, the rough fibrous surface requires the film to be pressed against the surface of the pulp base at a temperature and / or pressure somewhat less during the bonding process to ensure that the film still has sufficient strength so that it is not punctured by the unpowered fiber surface of the pulp base.

Formede fibermassegrundlag, der er produceret efter andre velkendte fiberformningsprocesser, er ligeledes anvendelige ved udovelse af opfindelsen. Dette gælder ogsâ formede fibermasseemner, som ferst er formet i overensstemmelse 20 med -fpitorringsprocessen, og dernssst "efterpresset" pâ den i USA patent nr. 2 704 493 angivne mâde. Dette gælder ogsâ formede fibermasseemner, som ferst formes i overens-stemmelse med fritorringsprocessen, og dernæst anbringes i âbne”forme, som forhindrer emnerne x at slâ sig. Formene 25 bevæger si g pâ et transportbând gennem en torreovn og hol-der blot emnerne for at modvirke deformationer pâ grund af, at emnerne slâr sig under terringsprocessen, hvilket f.eksT er beskrevet i USA patent nr. 3 185 370.Molded fiber pulp foundations produced by other well-known fiber forming processes are also useful in practicing the invention. This also applies to molded fiber pulp blanks, which are molded in accordance with the coating process, and then "post-pressed" in the manner disclosed in U.S. Patent No. 2,704,493. This also applies to molded fiber pulp blanks, which are molded in accordance with the frying ring process, and then placed in open molds that prevent blanks x from settling. The molds 25 move a conveyor belt through a drying furnace and simply hold the blanks to counteract deformation due to blanks during the tearing process, as described, for example, in U.S. Patent No. 3,185,370.

Ved fremgangsmâden ifolge opfindelsen anvendes fortrinsvis 30 en masse af hovedsagelig 100% blegede fibre af krafttræ.In the method of the invention, preferably a mass of substantially 100% bleached kraft wood fibers is used.

Dette materiale foretrækkes, fordi det ikke bliver brunt i den betydning, at det ved udsættelse for en temperatur pâ omkring 204°C i 15 minutter ikke ændrer sin attraktive hvide farve i vaesentlig grad til en meget uonsket brun, 7This material is preferred because it does not turn brown in the sense that, upon exposure to a temperature of about 204 ° C for 15 minutes, it does not substantially change its attractive white color to a very undesirable brown, 7

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men mâske en smule mere gui, og exnnet vil helt sikkert ikke blive svedet eler forkullet. Nâr f0devarer eller lignende indhold ved stuetemperatur eller derunder er i umiddelbar nærhed af materialet, fungerer indholdet 5 soin et varmedræn for emnet, sâledes at dette kan udsaet-tes for temperaturer op til 232°C i 15 minutter uden væsentlig tegn pâ bruning.but maybe a little more gui, and the exnnet will certainly not be sweated or charred. When food or similar contents at room temperature or below are in the immediate vicinity of the material, the contents will function as a heat sink for the workpiece, so that it can be subjected to temperatures up to 232 ° C for 15 minutes without any significant sign of browning.

André typer og grader af fibermasse kan imidlertid anvendes, nâr slutproduktet ikke skal udsættes for sâdanne tempera-10 turer i den nævnte tid.However, different types and grades of fiber pulp can be used when the final product is not to be subjected to such temperatures during the said time.

Uanset formningsprocessen eller typen eller graden af masse til opnâelse af grundlaget kan denne behandles med fluor-carbonolie, som skyende overfladelag og/eller reaktiv syn-tetisk vandoverfladelag eller andre kendte overfladelag, 15 som helt overraskende ikke griber forstyrrende ind i bin-dingsfasen, som er forklaret i det folgende.Regardless of the molding process or the type or degree of mass to obtain the base, it can be treated with fluorocarbon oil as a cloud surface layer and / or reactive synthetic water surface layer or other known surface layer which, surprisingly, does not interfere with the bonding phase which is explained in the following.

Hvad enten det formede fibermassegrundlag er fremstillet i overensstemmelse med præcisionsformeprocessen eller af én af de mange variationer af fritorringsprocessen, er de 20 i aile tilfælde formet til næsten færdig tre-dimensional form, som kan formes enkelt eller kompliceret, fladt eller dybt, ait efter den brug, man skal gore af det polyester-beklædte produkt. I hvert tilfælde indeholder kontureme vandrette vægomrâder og skrânende vægomrâder, men i det 25 væsentlige ingen lodrette vægomrâder.Whether the molded fiber pulp foundation is manufactured in accordance with the precision molding process or one of the many variations of the fryer ring process, the 20 are in all cases formed into almost complete three-dimensional molding, which can be formed simply or complicated, flat or deep, according to it. use, one must make of the polyester-coated product. In each case, the contours contain horizontal wall areas and sloping wall areas, but essentially no vertical wall areas.

Yed at undgâ væsentlige lodrette vægomrâder bortset fra mindre lodrette skuldre eller fremspring af den type, som benyttes til at modvirke klemning eller væltning, hvis emneme er stablet oven pâ hinanden, er det muligt, at en 30 mængde af ens tomme grundlag og naturligvis ogsâ de fra grundlagene færdige beklædte produkter, kan anbringes oven pâ hinanden til en kompakt stabel, der billigt og nemt kan transporteres og opbevares. Af samme grund har det formede fibermassegrundlag og de deraf fremstillede færdige beklæd- 8In order to avoid significant vertical wall areas other than smaller vertical shoulders or protrusions of the type used to counteract clamping or overturning if the blanks are stacked on top of one another, it is possible that a 30 amount of even blank base and of course the from the finished finished products can be placed on top of each other into a compact stack that can be transported and stored cheaply and easily. For the same reason, the molded fiber pulp base and the finished coatings made therefrom 8

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te produkter en næsten ensartet enkelt tykkelse hen over det hele, forstâet pâ den mâde, at ethvert omrids, som rager ud fra produktets ene side, svarer til en tilsvarende fordybning i den anden side af produktet.tea products an almost uniform single thickness over the whole, in the sense that any outline projecting from one side of the product corresponds to a corresponding depression in the other side of the product.

5 For det andet er polyethylenterephthalatfilmen, hvoraf be-klædningen pâ det formede fibermassegrundlag frembringes, en tynd film af varmedeformerbart, i det væsentlige amorf ikke orienteret polyethylenterephthalat, som forstâs at hâve en relativt hej molekylevægt. Skent sâdant polyethylen-10 terephthalat er tilgængeligt i pladeform med en tykkelse pâ omkring 0,025 mm,· foretrækkes det at udeve opfindelsen med et sâdant materiale i tyndere filmform med en tykkelse pâ mindre end omkring 0,025 mm. Et sâdant materiale er kommer-cielt tilgængeligt under navnet "Petra", og mange af de i 15 det efterf0lgende omtalte egenskaber er formentlig forkla-ret i det'tyske patentskrift nr. 2 125 978.Second, the polyethylene terephthalate film from which the coating is formed on the fibrous pulp basis is a thin film of heat-deformable, substantially amorphous, non-oriented polyethylene terephthalate which is understood to have a relatively high molecular weight. It is preferred that such polyethylene terephthalate is available in plate form having a thickness of about 0.025 mm, it is preferred to practice the invention with such a thin film material having a thickness of less than about 0.025 mm. Such a material is commercially available under the name "Petra" and many of the properties mentioned in the following are probably explained in German Patent Specification No. 2 125 978.

Ifolge en foretrukket udforelsesform, hvor en film med et sâdant polyethylenterephthalat er bundet til et grundlag med en glat overflade, som er fremstillet ud fra præcisions-20 formeprocessen, foretrækkes en film pâ imellem 0f012 mm og 0,050 mm, og film med en tykkelse pâ omtrent 0,025 mm, nem-lig i omrâdet mellem 0,022 mm og 0,031 mm har vist sig meget tilfredsstillende. Hvis man ifolge opfindelsen frem-stiller meget indviklede og dybe beholdere, sâsom tebolle-25 bageforme med et antal dybe, tætliggende lommer eller for-dybninger.^ eller med formet fibermassegrundlag. ud fra fri-torringsprocessen med relativt ru overflader, kan noget tyk-kere film imidlertid være tilrâdelige for at afhjælpe al-vorlig strækning eller for at sikre sig, at der ikke opstâr 30 uenskede smâ huiler.According to a preferred embodiment, in which a film having such a polyethylene terephthalate is bonded to a smooth surface formed from the precision molding process, a film between 0x012 mm and 0.050 mm is preferred, and films having a thickness of approx. 0.025 mm, in the range of 0.022 mm to 0.031 mm has proved very satisfactory. If according to the invention, very intricate and deep containers are produced, such as teaspoon baking molds having a plurality of deep, dense pockets or depressions or with shaped pulp foundations. however, from the free-drying process with relatively rough surfaces, somewhat thicker films may be advisable to alleviate severe stretching or to ensure that 30 undesirable small weights do not occur.

Den if0lge opfindelsen anvendte polyethylenterephthalat-film er termoplastisk i den betydning, at den bliver ter-moplastisk i sâ stor en udstrækning, at den kan strækkes og formes ved en temperatur pâ over 76°C, sâ den felger 35 konturen af de ikke sâ dybt formede fibermassegrundlag.The polyethylene terephthalate film used in accordance with the invention is thermoplastic in the sense that it becomes thermoplastic to such an extent that it can be stretched and formed at a temperature above 76 ° C to rim the contour of the not-so-deep shaped fiber pulp foundations.

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Dette materiale smelter til en væske ved temperaturer pâ over 248°C - 254°C.This material melts into a liquid at temperatures above 248 ° C - 254 ° C.

Denne film er hovedsagelig amorf, næsten gennemsigtig og indholdet af krystaller er mindre end %. Over den laveste 5 termoplastiske temperatur og under smeltepunktet vil dette materiale imidlertid spontant krystalliseres. F.eks. vil en film med en tykkelse pâ omkring 0,025 mm krystalliseres næsten helt pâ 2 til 15 sekunder ved en temperatur pâ mel-lem 121°C og 204°C. Nâr filmen holdes et sâdant tidsrum 10 inden for krystalliseringstemperaturomrâdet, ændres den fra i det væsentlige gennemsigtig til gennemskinnelig hvid, hvilket er tegn pâ foroget krystaldannelse. Samtidig bliver filmen skor og har svært ved at binde sig til'formet fiber-masse ved en temperatur pâ under ca. 204°C. Det er imidler-15 tid bemærkelsesværdigt, at en udsættelse af filmen for krystalliseringstemperaturomrâdet pâ mindre end fâ sekunder ikke medforer en skadelig foregelse af krystalindholdet som har en særlig uheldig virkning enten pâ plasticiteten eller pâ filmens bindende egenskaber. Dette er en egenskab, 20 som formentlig kan være ansvarlig for mange af de forbedre-de resultater, der opnâs ved opfindelsen, hvilket i det folgende forklares mere udferligt.This film is mostly amorphous, almost transparent and the content of crystals is less than%. However, above the lowest thermoplastic temperature and below the melting point, this material will spontaneously crystallize. Eg. For example, a film of about 0.025 mm thick will crystallize almost completely in 2 to 15 seconds at a temperature between 121 ° C and 204 ° C. When the film is kept for such a period of time within the crystallization temperature range, it is changed from substantially transparent to translucent white, which is indicative of increased crystal formation. At the same time, the film becomes brittle and has difficulty in bonding to fibrous pulp at a temperature of below approx. 204 ° C. It is noteworthy, however, that exposure of the film to the crystallization temperature range in less than a few seconds does not cause a detrimental prediction of the crystal content which has a particularly adverse effect either on the plasticity or on the film's binding properties. This is a feature that can probably be responsible for many of the improved results obtained by the invention, which will be explained in greater detail below.

Den ifolge opfindelsen anvendelige polyethylenterephthalat-film er næsten helt uorienteret, hvilket skyldes, at filmen 25 ikke forsætligt strækkes under fremstillingen. Filmen formes ved at ekstrudere polyethylenterephthalatharpiks gennem en spaltematrice ved en temperatur pâ imellem 265°C og 282°C, og afkole det flade, tynde, ekstruderede materiale pâ en poleret rulle ved en temperatur pâ imellem 15°C og 93°C. En 30 mindre grad af længdeorientering opstâr utvivlsomt under ekstruderingen af formstoffet i filmen, men det er klart, at den grad af orientering er begrænset ved ekstrudering gennem spaltematricen og afkoling pâ en poleret rulle.The polyethylene terephthalate film usable in accordance with the invention is almost completely non-oriented, which is because the film 25 is not intentionally stretched during manufacture. The film is formed by extruding polyethylene terephthalate resin through a slit die at a temperature between 265 ° C and 282 ° C, and decolorizing the flat, thin, extruded material onto a polished roll at a temperature between 15 ° C and 93 ° C. A lesser degree of length orientation undoubtedly occurs during the extrusion of the plastic in the film, but it is clear that that degree of orientation is limited by extrusion through the slit matrix and decolourization on a polished roll.

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Det formodes, at anvendelsen af polyethylenterephthalat med relativho;] molekylvægt, er et vigtigt endskent mâske ikke et kritisk træk ved opfindelsen. Det har i praksis vist sIg, at materialer med molekylvægt pâ over 15 000, 5 nemlig i omrâdet 15 000 til 30 000, har vist sig at vsere anvendelige, og er nu foretrukket. Dette er i modsætning til den polyethylenterephthalat, der har en relativ lav molekylvægt, som f.eks. ikke overstiger 10 000. Det forventes imidlertid, at en film med molekylvægt sa lav som ca.It is believed that the use of relative high molecular weight polyethylene terephthalate is an important end result, perhaps not a critical feature of the invention. In practice, it has been shown that materials with a molecular weight in excess of 15,000, namely in the range of 15,000 to 30,000, have proved to be very useful and are now preferred. This is in contrast to the polyethylene terephthalate having a relatively low molecular weight such as e.g. does not exceed 10,000. However, a molecular weight film is expected to be as low as approx.

10 12 000 alligevel kan være anvendelig til produktion af be- klædte beholdere eller andre produkter, hvor konturen er flad, sâledes at filmen strækkês minimalt for bindingen, og hvor det færdige produkts anvendelse tillader, at den me-kaniske binding mellem beklædningen og grundlaget er mini-15 mal.10 12 000 may nevertheless be applicable to the production of coated containers or other products where the contour is flat, so that the film is stretched minimally for bonding and where the use of the finished product allows the mechanical bond between the coating and the foundation to be mini-template.

For det tredje bestâr bindingsprocessen, hvor filmen bindes til grundlaget, af folgende trin: foropvarmning af det præ- fabrikerede grundlag, hvis fremstilling er forklaret oven-for; hurtig foropvarmning af en film af polyethylentereph-20 thalat med de ovenfor angivne egenskaber, og dernæst hurtig varmepresning af den foropvarmede film i beroring med over-fladen af det foropvarmede grundlag, hvorpâ en beklædning skal dannes, hvilken varmepresning udfores ved en tempera-turog i et tidsrum, som sikrer, at filmen strækkês i direk-25 te beroring med grundlaget og bliver direkte bundet ved sin egen substans til grundlaget, sâ der dannes en sammenhæn-gende beklædning derpâ, og at grundlaget og beklædningen til sidst afkoles til stuetemperatur.Third, the bonding process in which the film is bonded to the foundation consists of the following steps: preheating the pre-fabricated basis, the preparation of which is explained above; rapid preheating of a polyethylene terephthalate film having the above properties, and then rapid heat pressing of the preheated film into contact with the surface of the preheated base upon which a coating is to be formed, which heat pressing is carried out at a temperature a period of time which ensures that the film is stretched in direct contact with the base and is directly bonded by its own substance to the base, so that a cohesive coating is formed thereon, and the foundation and the coating are finally cooled to room temperature.

Mere nojagtigt, og med henvisning til fig. 5, udfores den 30 foretrukne procès pâ folgende mâde. Det præ-formede, præci-sionsformede fibermassegrundlag 10 anbringes i en âben form 12, som er dimensioneret til helt at understotte grundlaget ved at understotte dets yderste overflade, som ikke er be-lagt med polyesterbeklædningen.More precisely, and with reference to FIG. 5, the 30 preferred process is carried out as follows. The preformed, precision shaped fibrous pulp 10 is placed in an open mold 12 which is sized to fully support the base by supporting its outer surface which is not coated with the polyester lining.

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I formen 12 findes sugeâbninger 14, som er forbundet med en vakuumkilde (ikke vist), sâledes at vakuum kan tilferes gennem grundlaget under processens bindingstrin. Fortrins-vis er det tilferte vakuum i omrâdet over 50 cm kvikselv, 5 selvom mindre værdier kan være egnet til fladt udformede emner og/eller tyndere film, og hejere værdier kan være tilrâdelige for de dybere udformede emner og/eller tykke-re film.In the mold 12, suction openings 14 are provided which are connected to a vacuum source (not shown) so that vacuum can be supplied through the base during the bonding step of the process. Preferably, the applied vacuum is in the region of over 50 cm of mercury, although smaller values may be suitable for flat shaped blanks and / or thinner films, and higher values may be suitable for the deeper shaped blanks and / or thicker films.

Formen 12 holdes pâ en temperatur i omrâdet mellem 148°C 10 og 332°C ved hjælp af traditionelle varmeorganer (der ikke er vist). Den hensigtsmæssige temperatur er valgt inden for dette omrâde for at sikre, at det formede fibermassegrund-lag i tidsrummet fra dets anbringelse i formen til bindings-fasen vil blive foropvarmet til sa hej en temperatur, at 15 den overflade, hvorpâ filmen skal anbringes, har en temperatur i omrâdet imellem 148°C og 190°C, hvilket betyder, at den modsatte overflade, som er i kontakt med den opvar-mede form, for en kort tid vil komme op pâ hejere tempera-turer. Nâr det formede fibermassegrundlag er relativt tykt, 20 og/eller nâr det har en udformning, der er relativt ind- viklet og/eller dyb, er en foropvarmning til en hejere temperatur nedvendigo Er grundlaget tyndere, hvor udformningen er relativ simpel og flad, eller kan en minimal bindings-evne mellem grundlag og film tillades, vil foropvarmnings-25 temperaturen befinde sig i den lavere ende af værdiomrâdet.The mold 12 is maintained at a temperature in the range of 148 ° C to 332 ° C by means of conventional heating means (not shown). The appropriate temperature is selected within this range to ensure that, during the time from its placement in the mold to the bonding phase, the formed fibrous pulp base will be preheated to such a temperature that the surface upon which the film is to be applied has a temperature in the range between 148 ° C and 190 ° C, which means that the opposite surface which is in contact with the heated mold will, for a short time, rise to higher temperatures. When the shaped fiber pulp foundation is relatively thick, and / or when it has a design that is relatively intricate and / or deep, a preheating to a higher temperature is downward. Is the foundation thinner where the design is relatively simple and flat, or If a minimum bonding ability between base and film is allowed, the preheating temperature will be at the lower end of the range.

I aile tilfælde er grundlaget foropvarmet for at sikre, at overfladen, hvor filmen skal bindes, har den onskede temperatur, og fortrinsvis, skent ikke n0dvendigvis, som et sim-pelt middel til at holde grundlaget 1 en opvarmet form i et 30 kort tidsrum.In all cases, the base is preheated to ensure that the surface on which the film is to be bonded has the desired temperature, and preferably, does not necessarily appear, as a simple means of keeping the base 1 in a heated form for a short period of time.

Polyethylenterephthalatfilmen 16 er ogsâ foropvarmet og an-bragt i en stilling tæt ved og oven over det formede masse-grundlags 10 overflade, hvorpâ filmen skal anbringes. Den mâde, hvorpâ filmen anbringes, er ikke et væsentligt træk 35 ved opfindelsen, siden det kan gérés pâ mange mâder. Det 12The polyethylene terephthalate film 16 is also preheated and placed in a position close to and above the surface of the formed pulp base 10 upon which the film is to be placed. The manner in which the film is applied is not an essential feature of the invention, since it can be done in many ways. It 12

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anbefales, at filmen anbringes i endelig stilling i forhold til grundlaget for eller i det mindste under foropvarmningen, da filmen hurtigt skal foropvarmes og derefter hurtigt pres--ses mod grundlaget.It is recommended that the film be placed in a final position in relation to the basis of, or at least during the preheating, since the film must be preheated quickly and then quickly pressed against the foundation.

5 Filmen kan foropvarmes pâ en hvilken som helst mâde, der sikrer, at filmens temperatur oges ved stuetemperatur til væsentlig over den temperatur, hvor den bliver termopla-stisk og pâ kort tid krystalliseres. I overensstemmelse med den foretrukne procès anbringes filmen 16 i kontakt med 10 en plade 18, som kan være overtrukket med et materiale, f.eks. teflon, for simpelthen at sikre/ at filmen 16 ikke klæber sig til pladen 18. Ved hjælp af passende opvarmnings-organer (der ikke er vist) holdes pladen 18 pâ en temperatur i omrâdet mellem ca. 162°C og 204°C, idet temperaturen inden 15 for dette omrâde vælges ud fra filmens tykkelse og dens molekylvægt. Tykkere film med en tykkelse pâ op til omkring 0,175 nm kræver, at pladen 18 holdes pâ en hojere temperatur i omrâdet, eller at filmen holdes i kontakt med pladen i et noget længere tidsrum. Er filmen tyndere med en tykkel-20 se pâ omkring 0,025 mm, kan den nodvendige foropvarmning ske hurtigere ved kontakt med en plade, hvis temperatur holdes i den nedre del af omrâdet.The film can be preheated in any way to ensure that the film's temperature rises at room temperature to substantially above the temperature at which it becomes thermoplastic and in a short time crystallizes. In accordance with the preferred process, the film 16 is placed in contact with a plate 18 which may be coated with a material, e.g. teflon, to simply ensure / that the film 16 does not adhere to the plate 18. By means of suitable heating means (not shown), the plate 18 is kept at a temperature in the range between approx. 162 ° C and 204 ° C, the temperature within this range being chosen based on the thickness of the film and its molecular weight. Thicker films with a thickness of up to about 0.175 nm require the plate 18 to be maintained at a higher temperature in the area or the film be kept in contact with the plate for a somewhat longer period of time. If the film is thinner with a thickness of about 0.025 mm, the necessary preheating can be done more quickly by contact with a plate whose temperature is kept in the lower part of the area.

Filmen bar foropvarmes hurtigt, i det mindste i den del af foropvarmningsperioden, hvor temperaturen er i det omrâde, 25 hvor. pQlyethylenterephthalatfilmen krystalliserer. Er f.eks. filmens tykkelse mellem ca. 0,012 og 0,05 mm, foropvarmes filmen fra stuetemperatur til bindingstemperaturen i et tidsrum, som ikke overstiger ca. 2 sekunder.The film should be preheated quickly, at least during the part of the preheating period where the temperature is in the range where. The pQlyethylene terephthalate film crystallizes. For example, the film thickness between approx. 0.012 and 0.05 mm, the film is preheated from room temperature to the bonding temperature for a period not exceeding approx. Two seconds.

Sâ snart filmen er blevet foropvarmet til den onskede tem-30 peratur, og grundlaget er blevet passende foropvarmet, su-ges filmen ned i kontakt med den eller de overflader i grundlaget 10, som onskes dækket, ved hjælp af et under-tryk, der virker gennem grundlaget. Filmen, sôm er i den foropvarmede tilstand, strækkes, sà den kommer i direkte 13As soon as the film has been preheated to the desired temperature and the base has been suitably preheated, the film is sucked into contact with the surface (s) of the base (10) which is desired to be covered by a vacuum which works through the foundation. The film, which is in the preheated state, is stretched so that it comes in direct 13

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kontakt med det formede grundlag, og filmen bliver tyndere i en udstrækning, der bestemmes af formeme og dybdeme af grundlagets udformning. Vedvarende anvendelse af det ved vakuum skabte tryk sikrer, at filmen bindes til det formede 5 fibermassegrundlags overste flade eller flader, idet et lag af filmen ved den flade, der vender mod grundlaget, for-deles ind imellem de torrede fibre i grundlagets overste flade eller flader.contact with the shaped base, and the film becomes thinner to an extent determined by the shapes and depths of the base design. Continuous use of the vacuum created pressure ensures that the film is bonded to the top surface or surfaces of the formed fibrous pulp foundation, a layer of the film at the surface facing the base is divided between the dried fibers in the top surface of the base or surfaces.

Hvis det onskes, kan filmen suges ind imod begge grundla-10 gets sider, f.eks. pâ undersiden af det formede fibeisnasse-grundlags yderste flange, hvilket er forklaret i.det for-nævnte USA patent nr. 3 657 044; men det er helt valgfrit.If desired, the film can be sucked in against both sides of the base layer, e.g. on the underside of the outer flange of the molded fibrous snout base, which is explained in the aforementioned United States Patent No. 3,657,044; but it is completely optional.

Pâ lignende mâde kan pressefasen, hvor filmen bringes i kontakt med grundlaget, omfatte et overtryk eller mekanisk 15 tryk i stedet for eller i tilknytning til undertrykket, f.eks. kan en bevægelig formdel presse filmen imod den y-derste flange eller andre dele pâ grundlaget, endskont dette ogsâ er anset for at være en helt frivillig fremgangs-mâde. Pâ samme mâde kan filmen presses mod kun en del af 20 grundlagets overflader, f.eks. i situationer, hvor grundlaget indeholder en fordybning, der udgor en beholder, som ved hjælp af hængsler er forbundet med en lâgdel, der kan lukke beholderen, og hvor kun det inderste af fordybningen skal beklædes med plast. Endvidere kan enten grundlaget 25 eller filmen eller begge dele indeholde en pâtrykning, hvis formai er af dekorativ, informativ eller lignende art, og formâlet med opfindelsen vil ogsâ blive opnâet, hvis pâ-trykningen er beliggende i grænsefladen mellem grundlaget og filmen, eller hvis pâtrykningsmediet har klæbende egen-30 skaber.Similarly, the pressing phase in which the film is brought into contact with the base may comprise an overpressure or mechanical pressure in place of or in connection with the negative pressure, e.g. For example, a movable mold member may press the film against the outer flange or other parts of the base, although this is also considered to be a completely voluntary procedure. Similarly, the film can be pressed against only a portion of the surface of the base, e.g. in situations where the foundation contains a recess which constitutes a container, which is connected by hinges to a lid which can close the container and where only the innermost part of the recess must be covered with plastic. Furthermore, either the base 25 or the film or both may contain a print of a decorative, informative or similar nature and the object of the invention will also be achieved if the print is located in the interface between the foundation and the film or if the print medium has adhesive properties.

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Processens pressefase vedvarer i et stykke tid, f.eks. flere sekunder eller mindre, for at sikre en passende fysisk Mnding mellem filmen og grundlaget. Det har vist sig, at en usædvanlig stærk Mnding kan opnâs 5 mellem plasten og fibermassen pâ mindre end 1 sekund, nâr grundlaget og filmen er foropvarmet efter oven-nævnte metode, og filmen er presset ned til kontakt med grundlaget ved hjælp af et undertryk, hvis værdi befinder sig i omrâdet omkring 50 cm kviksolv. En po-10 lyethylenterephthalatfilm, hvis tykkelse er pâ omkring 0,025 mm, kan bâde hurtigt foropvarmes og hurtigt presses ned til kontakt med et foropvarmet grundlag pâ mindre end 1 sekund totaltid.The pressing phase of the process persists for a while, e.g. several seconds or less to ensure an appropriate physical bond between the film and the foundation. It has been found that an exceptionally strong bond can be obtained between the plastic and the fiber mass in less than 1 second, when the base and film are preheated by the above method and the film is pressed down to contact the foundation by means of a vacuum. whose value is in the region of about 50 cm of mercury. A polyethylene terephthalate film having a thickness of about 0.025 mm can be both preheated and rapidly pressed down to contact a preheated base in less than 1 second total time.

Anvendes et mekanisk tryk eller anvendes overtryk, vil 15 den nedvendige tid, der skal til for at opnâ en passende binding, være kortere, hvilket er en meget vigtig betragtning ved masseproduktion. Derefter afkoles grundlaget og beklædningen til stuetemperatur. Den nuværende foretrukne afkelingsproces bestâr i at fjerne det be-20 klædte grundlag fra den opvarmede vakuumform 12, hvor- efter produktet afk0les langsomt til stuetemperatur. Efter at det formede fibermassegrundlag er fjernet fra den varme form 12, vil grundlaget stadig indeholde varme, der langsomt forsvinder, hvilket i det mindste kræver 25 flere minutter afhængigt af emnets masse og hvorvidt em-neme med det samme bliver stablet oven pâ hinanden til afkeling fra bindingstemperaturen til stuetemperaturen.If a mechanical pressure is used or overpressure is used, the required time required to obtain a suitable bond will be shorter, which is a very important consideration in mass production. Then the foundation and cladding are cooled to room temperature. The present preferred cooling process consists in removing the coated base from the heated vacuum form 12, after which the product is slowly cooled to room temperature. After the molded fiber pulp foundation is removed from the hot mold 12, the base will still contain slowly dissipating heat, requiring at least 25 more minutes depending on the mass of the blank and whether the blanks are immediately stacked on top of each other for cooling. from the bonding temperature to the room temperature.

Passende afklipning af overskydende film og/eller fi-bermasse, f.eks. produktets kanter eller rundt om hul-30 1er gennem produktet, kan udfores fer, under eller efter enten bindingsfasen eller afkelingsfasen ved hjælp af en hvilken som helst velkendt metode. Endelig forven-tes det nu, at en hærdning til sidst kan vise sig at være nyttig ved, at beklædningen krystalliseres yderligere, 35 hvorved dens egenskaber ved visse anvendelser forbedres.Appropriate clipping of excess film and / or fiber, e.g. The edges of the product or around holes through the product can be carried out, during or after either the bonding phase or the decaying phase, by any known method. Finally, it is now expected that a cure may eventually prove useful in further crystallizing the coating, thereby improving its properties in certain applications.

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Dette gérés ved at udsætte det færdige produkt for tem-peraturer i omrâdet mellem 121°C og 204°C i adskil-lige minutter eller længere tid.This is done by exposing the finished product to temperatures in the range of 121 ° C to 204 ° C for several minutes or longer.

For det fjerde bestâr det polyesterbeklædte formede 5 fibermasseprodukt 20 i det store og hele af præfa- brikeret formgivet grundlag 10, der bestâr af fiber-masse, som i nogle tilfælde kan indeholde et eller flere bindemidler. En beklædning er direkte bundet til i det mindste et formgivet omrâde pâ i det mindste 10 en af grundlagets sider, som vist i fig. 4. Beklædnin-gen 22 er i det væsentlige uigennemtrængelig og bestâr hovedsageligt af polyethylenterephthalat, som kan ud-sættes for temperaturer pâ op til 204°C uden at krympe og lesne sig fra det formgivne grundlag 10.Fourth, the polyester coated 5 fiber pulp product 20 consists largely of prefabricated shaped base 10, consisting of fiber pulp, which may in some cases contain one or more binders. A lining is directly bonded to at least one shaped area on at least one of the sides of the base, as shown in FIG. 4. The lining 22 is substantially impervious and consists mainly of polyethylene terephthalate which can be exposed to temperatures up to 204 ° C without shrinking and reading from the molded base 10.

15 Som ferst forklaret i det foregâende i forbindelse med det præfabrikerede grundlags detailbeskrivelse frem-stilles produktets grundlag ifelge den foretrukne ud-ferelsesform ved at forme fibermasse, sâ den i det store og hele fâr den endelige fora, hvorefter fiber-20 massen terres under tryk ved hjælp af et par sammen- herende opvarmede forme. Fibermassen bestâr i det væsentlige af 100% blegede fibre af krafttræ, der ikke udviser nogen nævneværdig uensket bruning pâ grand af at det udsættes for temperaturer pâ ca. 204°C i op til 25 15 minutter.15 As previously explained in connection with the detailed description of the prefabricated base, the product base is prepared according to the preferred embodiment by forming fibrous pulp, so that it largely obtains the final forums, after which the fiber pulp is pressurized. using a pair of interlocking heated molds. The fiber pulp consists essentially of 100% bleached kraft wood fibers which exhibit no appreciable undesirable browning due to exposure to temperatures of approx. 204 ° C for up to 25 15 minutes.

Det er yderligere forklaret i det foregâende, at hvis po-lyesterterephthalatbeklædningen opnâet ved fremgangsiaâden ifelge opfindelsen adskilles fra grundlaget, vil det vise sig ikke at være let at binde det til formet fibermasse, 50 hvis temperatur er under ca. 204°C. Beklædningen har en krystallinitet pâ mindst ca. 8%, som kan være ansvarlig for det faktum, at materialet ikke let bindes til formet fibermasse pâ samme mâde som den forste film. Den stærke bin-ding, der oprindeligt opnâedes ved den procès, er imid- 16It is further explained in the foregoing that if the polyester terephthalate coating obtained by the process of the invention is separated from the foundation, it will not be easy to bond it to molded fiber pulp 50, the temperature of which is below approx. 204 ° C. The coating has a crystallinity of at least approx. 8%, which may be responsible for the fact that the material does not readily bond to molded fiber pulp in the same way as the first film. However, the strong bond originally gained by that process is 16

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lertid ikke ugunstigt pâvirket ved det efterfolgende tab af bindingsegenskaber.however, not adversely affected by the subsequent loss of binding properties.

Repræsentative produkter opnâet ved fremgangsmâden ifolge opfindelsen er vist i fig. 1 og 2. Fig. 1 er en perspek-5 tivtegning af en relativ simpel og flad udformet beholder 30, som er beregnet til servering af fodevarer, og som har vandrette grundflader 32, et horisontalt flangeomrâde 34, skrânende sideomrâder 36 samt skrânende adskillelses-omrâder 38, men ingen næsten vertikale vægomrâder.Representative products obtained by the method according to the invention are shown in FIG. 1 and 2. FIG. 1 is a perspective view of a relatively simple and flat shaped container 30, which is intended for serving foodstuffs, having horizontal bases 32, a horizontal flange area 34, sloping side areas 36 and sloping separation areas 38, but no vertical wall areas.

10 Fig. 2 er en perspektivtegning af en relativt indviklet og dybt udformet tebollebageform 40, der er tredimensio-nalt udformet med horisontale grundfladeomrâder 42, horisontale ovre flader 44 og stejlt skrânende relativt dybe omrâder, som udgor en mængde taet pakkede lommer 15 46, men ingen næsten vertikale vægomrâder.FIG. 2 is a perspective view of a relatively intricate and deeply formed tea bowl baking mold 40, having three-dimensional shapes with horizontal base areas 42, horizontal upper surfaces 44, and steeply sloping relatively deep areas forming a plurality of tightly packed pockets 15, but no nearly vertical vægomrâder.

I aile tilfælde er beholderen eller andre produkter opnâet ved fremgangsmâden ifolge opfindelsen tredimensio-nalt formgivet næsten uden vertikale vægomrâder for at tillade, at en mængde ens tomme beholdere, som f.eks.In all cases, the container or other products obtained by the method according to the invention are designed three-dimensionally, almost without vertical wall areas, to allow an amount of even empty containers, such as e.g.

20 beholderne'50, der er vist brudstykkevis i fig. 3, kan stables dybt eller fladt oven pâ hinanden, sâledes at stabelen kan transporteres og opbevares kompakt, bekvemt og okonomisk. Smâ vertikale vægomrâder 52 kan forekomme for at modvirke knusning af beholderne og for at lette 25 adskillelsen af de stablede beholdere, hvilket er vel-kendt.20 the containers 50 shown in fragmentary view in FIG. 3, can be stacked deep or flat on top of each other, so that the stack can be transported and stored compactly, conveniently and economically. Small vertical wall areas 52 may exist to counteract crushing of the containers and to facilitate separation of the stacked containers, as is well known.

Produktet opnâet ifolge opfindelsen, som f.eks. er en ovnfast madbeholder, kan udsættes for temperaturer pâ ca. 204°C i op til 15 minutter uden at det formede fiber-30 massegrundlag udviser en nævneværdig uonsket bruning (selv om fibermassegrundlaget vil brunes og eventuelt forkulles, hvis det holdes pâ sâ hoj en temperatur i 17The product obtained according to the invention, e.g. is an ovenproof food container, can be exposed to temperatures of approx. 204 ° C for up to 15 minutes without the shaped fibrous pulp showing a significant undesired browning (although the pulp base will brown and possibly char if kept at such a high temperature for 17

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længere tid end 15 minutter).longer than 15 minutes).

I virkeligheden kan et produkt opnâet ved fremgangsmâden if0lge opfindelsen tâle h0jere temperaturer i længere tid, nâr fodevareprodukter eller lignende opvarmes i beholderen. Hvis f.eks. bageformen i fig. 2 er fyldt med dej i aile rum og begge dele ved start har stue-temperatur, kan tebollebageformen ved bagning af teboller udsættes for temperaturer sa h0je som 232°C i op til 45 minutter, uden at beklædningen l0snes eller fibermassen brunes. Grunden til dette er, at dejen under opvarmningen og bagningen udgor et varmedræn, hvilket forhindrer, at selve formen kommer op pâ en temperatur pâ ca. 204°C i me.re end 15 minutter; dog kan de af beholderens hj®rner, som ligger længst væk fra tebollefordybningerne, udvise gulning ved slutningen af 45 minutters perioden.In fact, a product obtained by the method according to the invention can withstand higher temperatures for a longer period of time when food products or the like are heated in the container. For example, the baking mold of FIG. 2 is filled with dough in all rooms and both at room temperature have room temperature, the baking tray baking form can be exposed to temperatures as high as 232 ° C for up to 45 minutes without baking or coating the pulp. The reason for this is that during the heating and baking the dough forms a heat drain, which prevents the mold itself from reaching a temperature of approx. 204 ° C for more than 15 minutes; however, at the end of the 45-minute period, those of the container's corners, which are furthest away from the tea bunks, may show yellowing.

Ligeledes kan beholderen i fig. 1,. der er beregnet til servering af fodevarer, udsættes for temperaturer sâ ho je som ca. 232°C i op t±lr45 minutter uden at beklædningen losnes eller fibermassen brunes, hvis den indeholder en dybfrossen anretning, som skal opvarmes med eller uden yderligere væsentlig tilberedning. Tem-peraturen og tiderne afhænger af beholderens masse og særlig indflydelse har beholderens og indholdets be-gyndelsestemperatur samt den opvarmede fodevares masse og form. Desuden vil de endelige brugsparametre afhæn-ge af den mâde, hvorpâ varmen tilfores beholderen og indholdet. En sædvanlig konventionsovn til hjemmebrug tilforer varmen pâ en mâde, der er forskellig fra den mâde, hvorpâ en kontaktovn til industri tilforer varmen. Begge opvarmer dog beholderen sâvel som indholdet, hvorimod en mikrobolgeovn direkte opvarmer indholdet uden at opvarme beholderen, der kun opvarmes indirekte ved hjælp af det varme indhold.Also, the container of FIG. 1 ,. intended for serving food is exposed to temperatures as high as approx. 232 ° C for up to ± 45 minutes without loosening the lining or browning the pulp if it contains a deep-frozen device which is to be heated with or without further essential preparation. The temperature and times depend on the mass of the container and the particular influence has on the initial temperature of the container and the contents, as well as the mass and shape of the heated food. In addition, the final operating parameters will depend on the manner in which the heat is supplied to the container and the contents. A conventional home-use convention furnace supplies heat in a manner different from that in which an industrial contact furnace supplies heat. However, both heat the container as well as the contents, whereas a microwave oven directly heats the contents without heating the container, which is heated only indirectly by the hot content.

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I den sidstnævnte henseende har den ovnfaste beholder ifolge den foretrukne udforelsesform mange fordele frem for fodevarebeholdere af f.eks. aluminium. I modsaetning til aluminium er beholderen opnâet ved fremgangsmâden 5 ifolge opfindelsen gennemtrængelig for mikrobolger, sâledes at beholderen kan anvendes til enten mikrobolge-eller varmeovne. Produktet opnâet ved fremgangsmâden ifolge opfindelsen er mindre energikrævende at fremstille end aluminiumsbeholdere, og kan i modsaetning til disse 10 genbruges.In the latter respect, according to the preferred embodiment, the oven-proof container has many advantages over food containers of e.g. aluminum. Unlike aluminum, the container obtained by the method 5 according to the invention is permeable to microwaves, so that the container can be used for either microwave or heating ovens. The product obtained by the process according to the invention is less energy intensive to produce than aluminum containers and, in contrast to these, can be recycled.

Nâr et produkt opnâet ved fremgangsmâden ifolge opfindelsen opvarmes ved egentlig brug, formodes det, at polyethylenterephthalat-beklædningens krystalindhold foroges, hvilket formindsker beklaedningens tendens til 15 krympning og adskillelse fra grundlaget, selv om det kan begynde at miste nogle af dets oprindelige egenskaber pâ grund af, at grundlaget udsættes for hoje temperaturer i lang tid. Er denne formodning korrekt, har produkterne opnâet ved fremgangsmâden ifolge opfindelsen ikke faste 20 egenskaber, nâr produkterne udsættes for varme under brug; det er snarere sâdan, at varmen ændrer bâde fiber-massen og polyesterens egenskaber, men pâ en mâde, som stadig er forenelig med kravene til en ovnfast beholder til madvarer.When a product obtained by the process of the invention is heated by actual use, it is assumed that the crystal content of the polyethylene terephthalate cladding is increased, which reduces the cladding tendency to shrinkage and separation from the foundation, although it may begin to lose some of its original properties. that the foundation is exposed to high temperatures for a long time. If this assumption is correct, the products obtained by the process according to the invention do not have solid properties when the products are exposed to heat during use; rather, the heat changes both the fiber mass and the properties of the polyester, but in a way that is still compatible with the requirements of an ovenproof container for food products.

Claims (9)

1. Fremgangsmâde til direkte at sammenfoje et i det væsentlige ugennemskinneligt polyesterlag med en ved konturformning fremstillet massebund, og som omfatter 5 trin med (I) foropvarmning af en i forvejen formet bund (10), som er fremstillet ved at forme fibermasse ud fra en vandig opslæmning, som er anbragt i en âben su-geform (12), der næsten giver den endelige form, som omfatter horisontale og skranende vægge, men i hovedsa-10 gen ingen vertikale vægge, af (II) foropvarmning af en polyesterfolie (16) og af (III), at man derefter presser den foropvarmede folie (16) i beroring med mindst en konturformet del af i det mindste en overflade af den foropvarmede bund (10), at folien (16) strækkes 15 til direkte beroring med den konturformede bund (10) og forbindes direkte med bunden (10), sâledes at folien danner en tæt sammenhængende og udelt beklædning (22) pâ bunden, kendetegnet ved, at polyesterfo-lien (16), som udgôres af et (a) i hovedsagen amorft, 20. hovedsagen uorienteret polyethylenterephthalat (b) forvarmes til en termoformningstemperatur inden for det omrâde, ved hvilket den i det væsentlige krystallise-res i tid, men derefter (c) hurtigt presses til kontakt med og forbindes med bunden, medens folien vedvarende 25 er amorf, og inden der er forlobet tilstrækkelig tid ved det temperaturomrâde, hvor polyethylenterephthtalatet krystalliseres til det stadium, hvor det ikke straks fæstnes til bunden, sâledes at folien (16) efter afk-0-ling til stuetemperatur ikke vil krympe og losne sig 30 fra bunden (10) som et résultat af pâ hinanden folgen-de opvarmninger, hvor den udsættes for en temperatur pâ op til ca. 204°C. DK 157178BA method of directly joining a substantially opaque polyester layer to a contoured pulp base comprising 5 steps of (I) preheating a pre-formed bottom (10) formed by forming fibrous pulp from a aqueous slurry disposed in an open suction mold (12) which gives almost the final shape, which includes horizontal and sloping walls, but substantially no vertical walls, of (II) preheating a polyester film (16) ) and (III) then pressing the preheated foil (16) into contact with at least one contoured portion of at least one surface of the preheated bottom (10) extending the foil (16) to direct contact with it. contoured bottom (10) and bonded directly to the bottom (10) so that the film forms a tightly coherent and undivided coating (22) on the bottom, characterized in that the polyester film (16) formed by a (a) in the main case amorphous, 20. mainly unoriented polyeth ylenterephthalate (b) is preheated to a thermoforming temperature within the range at which it is substantially crystallized in time but then (c) rapidly pressed into contact with and bonded to the bottom while the film is persistently amorphous and before sufficient time has elapsed at the temperature range at which the polyethylene terephthalate crystallizes to the stage where it is not immediately adhered to the bottom, so that the film (16), after settling to room temperature, will not shrink and detach from the bottom (10) as a result of consecutive heats, where it is exposed to a temperature of up to approx. 204 ° C. DK 157178B 2. Fremgangsmâde if0lge krav 1, kendetegnet vedf at folien (16), som har en tykkelse, som er min-dre end ca. 2 mm, foropvarmes til en varmeformningstempera tur i omrâdet imellem 121°C og 204°C, men at den 5 derefter hurtigt presses til ber0ring med og forbindes med bunden, inden folien (16) har haft denne varmeform-ningstemperatur længere end ca. 2 sekunder.A method according to claim 1, characterized in that the film (16) having a thickness less than approx. 2 mm, is preheated to a heat forming temperature in the range between 121 ° C and 204 ° C, but is then rapidly pressed into contact with and bonded to the bottom before the foil (16) has had this heat forming temperature longer than approx. Two seconds. 3. Fremgangsmâde ifolge krav 2, kendetegnet ved, at bunden (10) fremstilles ved, at man former fi- 10 berholdig, i hovedsagen 100% bleget papirfibermasse ud fra en vandig opslæmning, som er anbragt i en âben sugeform (12), hvorefter fibermassen terres under tryk ved hjælp af et par samvirkende varmeforme.Method according to claim 2, characterized in that the bottom (10) is made by forming fibrous, generally 100% bleached paper fiber pulp from an aqueous slurry placed in an open suction mold (12), after which the fiber mass is pressurized by a pair of cooperating heat forms. 4. Fremgangsmâde ifolge krav 1, kendetegnet 15 ved, at udgangsfolien (16) af polyethylenterephthalat er næsten amorf og har en krystallisation, som er min-dre end 5%, og at krystallisationen af beklædningen (22), som er sammenfejet med bunden (10), er foroget til mindst ca. 8%.Process according to claim 1, characterized in that the starting foil (16) of polyethylene terephthalate is almost amorphous and has a crystallization of less than 5% and that the crystallization of the coating (22) is welded to the bottom ( 10), is increased to at least approx. 8%. 5. Fremgangsmâde ifolge krav 1, kendetegnet ved, at sammenfojningen udferes pâ en sâdan mâde, at den færdige beklædning (22) af polyethylenterephthalat ikke igen let bindes til den formede fibermasse ved en temperatur, som er under 204°C, hvis beklædningen 25 adskilles fra grundlaget.Process according to claim 1, characterized in that the joining is carried out in such a way that the finished coating (22) of polyethylene terephthalate is not readily bonded to the formed fiber mass at a temperature below 204 ° C if the coating 25 is separated. from the foundation. 6. Fremgangsmâde ifolge krav 1, kendetegnet ved, at polyethylenterephthalatet har en molekylvægt i omrâdet pâ ca. 15.000.Process according to claim 1, characterized in that the polyethylene terephthalate has a molecular weight in the range of approx. 15,000. 7. Fremgangsmâde ifolge krav 1, kendetegnet 30 ved, at udgangsfolien (16) af polyethylenterephthalat er termoplastisk ved og over en temperatur pâ ca. 76°C, DK 157178 B at der udfældes krystaller i den, nâr den i mere end fâ sekunder holdes pâ en temperatur i omrâdet imellem 121°C og 204°C, og at den smelter ved temperaturer, soin ligger over 248 til 254°C.Process according to claim 1, characterized in that the starting film (16) of polyethylene terephthalate is thermoplastic at and above a temperature of approx. 76 ° C, DK 157178 B crystals are precipitated in it when held for more than a few seconds at a temperature in the range between 121 ° C and 204 ° C, and melting at temperatures above 248 to 254 ° C. 8. Fremgangsmâde ifolge krav 7, kendetegnet ved, at bunden (10) foropvarmes sâiedes, at dens over-flade, som skal beklædes, har en temperatur i omrâdet mellem 148°C og 190°C, at udgangsfolien (16) af poly-ethylenterephthalat har en tykkelse pâ imellem 0,012 mm 10 og 0,05 mm, og at den foropvarmes fra stuetemperatur til en temperatur i omrâdet mellem 162°C og 204°C i et tidsrum, som ikke er længere end 2 sekunder, samt at den foropvarmede fo'l'i’e (16) hurtigt presses i kon-takt med den foropvarmede bund (10) ved hjælp af et undertryk pâ ca. 50 cm kviksolv, der virker gennem bun-15 den i ikke længere end 1 sekund.Method according to claim 7, characterized in that the bottom (10) is preheated so that its surface to be coated has a temperature in the range between 148 ° C and 190 ° C, that the exit foil (16) is made of polyethylene. ethylene terephthalate has a thickness of between 0.012 mm 10 and 0.05 mm and is preheated from room temperature to a temperature in the range of 162 ° C to 204 ° C for a period not exceeding 2 seconds and the preheated The foil (16) is rapidly pressed into contact with the preheated bottom (10) by means of a vacuum of approx. 50 cm of mercury that acts through the bottom for no longer than 1 second. 9. Fremgangsmâde ifolge krav 1, kendetegnet ved, at udgangsfolien (16) af polyethylenterephthalat har en tykkelse pâ ca. 0,025 mm, og at den bâde hur-20 tigt foropvarmes og derefter hurtigt presses i kontakt med den foropvarmede bund (10) i et totalt tidsrum pâ mindre end ca. 1 sekund.Method according to claim 1, characterized in that the starting film (16) of polyethylene terephthalate has a thickness of approx. 0.025 mm, and that it is both rapidly preheated and then rapidly pressed into contact with the preheated bottom (10) for a total time of less than approx. 1 second.