MULTILEVEL WRAPPING MATERIAL

The Erfindüng concerns a wrapping material, consisting of a layer of Sohaumplastik with fine void structure and homogeneous plastic films, which are arranged at both sides of this foam plastic layer, whereby those-foamed plastic layer exists a thickness of 0, 5 to 2 n m made of polystyrene foam and a density of 0, 05 to 0, 15 g/cm3 exhibits. In packing method often packing material used, which is compound from several layers, e.g. paper and plastic or cardboard and plastic, whereby paper or Kaßon task has to lend packaging material mechanical stiffness while the plastic serves on the one hand for it, to make to form work material with reference to packaged material closely and on the other hand protective film ftir paper, which otherwise easily humidity or liquid absorbs, if the paper thereby in contact ko t, whereby the mechanical characteristics, which are used, are lost. Even where it is possible to protect in the way indicated above the paper layer by coats from plastic or wax and prevent a Fl'üssigkeitsabsorption, nevertheless a considerable problem remains in connection with the planes of section of the layer packaging material, which exhibit an unprotected paper surface, through which a liquid absorption takes place easily and to leads that at least partly a decrease of the firmness of the finished packing eintrit. Wennes also in most cases succeeds to e.g. stick this mentioned problem with Paplerverbundpackstoffen by Abdeekstreifen - plastic material over the planes of section - to solve, was it sees desired to since-long to produce a mehrsehichtiges wrapping material which does not exhibit a liquid however nevertheless absorhieß the necessary Steifheitseigensehaf EN. A way, this problem too solve exists in it that in place of a Kopierschicht as reinforcing NIaterial relaüv a thick Schaumplastikmateria], e.g. polystyrene one uses. The foam plastic material for itself alone does not possess remarkable physical properties, but w n one it with two homogeneous plastic films combined and these in a certain distance from each other fastened, is obtained a bar effect at the bonding material, which causes very good safety characteristics, even if the homogeneous plastic material in this bonding material does not possess this Eigenschaf±. Such Verbundpaekmaterial absorbs no humidity and absorbs no liquid, since the foamed plastic material consists of a large number of closed pores or cells. But a disadvantage of such a packing material exists in the fact that it is relatively fragile and that the homogeneous plastic films often break, if they are exposed to the effect of a ST it e.g. with the production of a packing, if the Verpackungsmaterisl is folded strong or if the finished packing is exposed to impacts during transport and reloading. Natural is it particularly important that the homogeneous plastic film, which forms the inside of the finished packing does not exhibit tears and that can is reached by use of a Paekmaterials in accordance with the invention, and zw. a wrapping material, which is essentially by it characterized that those homogeneous plastic film of the compound wrapping material, which is turned to the packed property consists of a mixture of styrene and butadiene, a modulus of elasticity from 14000 to 20000 and a dead weight from 50 to 100 g/m2 possesses and that the homogeneous plastic film of the bonding material, which is to form the exterior that-finished packing consists essentially only of Polys yrol and a Elastizitätsmodu] from 30000 to 50000 and a dead weight from 30 to 80 g/m2 possesses. That lead one soIeherart zusam nengesetzten packing material exists therein that it notice-noticing who is rigid, so that the packings, which are produced with this Verpackungsmaterlal, are very rigid and firm. If such a packing is extremely stressed, e.g. with the Zubodenstürzen of the package, the internal layer from PolystyroI Bu&adien functions as Gum ischicht, which means that the danger of a blow-out of the internal layer is very small. Compound wrapping material above mentioned kind possesses interior layer, which not breaks, if it demands suspended, since butadiene, which is added to the polystyrene material, effect higher Brnchdehnung effectuation, which is called the material has the characteristic that it stretches, if it is suspended mechanical loads to a remarkable extent, before it rubs. A further characteristic of the invention consists of that the Kunststeffschicht, which is to form the inside of the feßigen packing exhibits an elongation at rupture border from 10 to 100% and the Kunststoffsehicht, which Außenseiteder packing is to form an elongation at rupture border from 2 to 10%. Finally is it still vorteflhaß, if between the foamed plastic film and possibly or both the homogeneous Kunststoffschlchten one is relatively gas density layer from nylon, Satan, PVC, Barex od. such arranged. In the following a compound wrapping material is more near described in accordance with the invention, whereby to the designs is referred. Fig. 1 shows an increased cross section by a compound wrapping material and a Fig. a course stretch diagram for dle layers shows 2 --1 and 3-- the compound wrapping material, of which the layer --1-- the inside of the finished packing to form is. On the x axis of the Coordinatensystems the stretch (or aspect ratio) of the material is laid on in per cent of its original length, during on the y axis Zugbzw. Druckbelasümgen of the material in kp/cm2 are laid on. From absolute data had to be refrained, because the Delmung of the material is dependent on its special composition. The cross section of the compound packing material, that in Fig. 1 is shown, points a middle thicker layer--2--from foamed polystyrene with small closed cells up. The thickness of this layer --2--can do 0, 5 to 2 mm, preferably approximately 1 mm and the density of the material is 0, 5 to 0, 15 g/cm3 to amount to. The layer --1-- the compound wrapping material, which is to form the Innenselte of the finished packing, consists of a layer of so-called hochst ßfestem polystyrene, i.e. from a mixture from PolystyroI with butadiene and the material is to possess a Elastizttätsmodul between 14000 and 20000. The layer--i-- a dead weight of 50 to 100 g/m2 preferably approximately 70 g/m2 is to possess and dle elongation at rupture border is between I0 and 100% to lie. The layer --3--, which should be the exterior of the packings made of the VerpackungsverbundmaterlaI, consists preferably of a crystalline polystyrene layer or a Polystyrolschlcht with a certain additive at butadiene. The Auftragsgewlcht (Elgengewicht of the layer) is to amount to 30 to 80 g/m2 and preferably 50 g/m2. The Elastizltätsmodul of the material, that the layer --3-- , is between 30000 and 50000 to lie and the elongation at rupture forms 2 to 10% amount to. DerVerpackungsschichtsteffwtrd preferably so manufactured that the foamed Plastikschtoht --2-- in actually well-known way is extruded and that afterwards the Überzugsschlchten --1 and 3-- with the help of the extruding procedure on both sides of the Schaumplastlkschicht in such a way to be added that a good adhesion between the outside layers --1 and 3-- and the Sohaumplastlkschlcht --2-- one obtains. The course stretch curves, those in Fig. 2 is represented, refers slch to the outside layers --1 and 3--, those in Fig. are shown 1 and the curves mlt for the sake of simplicity the same Bezugszelchen designated, i.e. also--1 and/or 3--. For better comprehensibility the Elasttzitätsmodale than a function of the derivative of the curves becomes following --1 and/or 3-- defined, while dle values of the materials indicated for the Elastlzltätsmoduls refer above to elasticity modules within the Porportlonalitätsgrenzen, i.e. on the first straight piece of the curves, where pressure, (course) and stretch of the material essentially stand to each other in linear relationship. Wle from the Fig. 2 to be taken can do, if one the curve --1-- regarded, those itself on the Überzugssohicht --1-- , has the material at the beginning refers a EIastlzItätsmodul (thus that modulus of elasticity in the ProportionalItätsbereioh), which is smaller than the appropriate Elastlzitätsmodul of the coat layer --3--. W is reached nn a Zugbelasümg, those in Fig. 2 with A it is more bezelchner then there is no linear relationship more between load, (course) and stretch, alIgemein is then stated that the material begins to give way, is called it stretches slch relatively more with relative gerin - towards Zugoder Druckznnahmen. If the Belasümg on the Materlalschicht --1-- up to the height of B, is very small the summit of the curve rose, i.e. the value of the modulus of elasticity at this point falls to a value, which can lie between 200 and 600 kg/cm2. This Weße of the elasticity modules is proportional the angles and/or fi, which are indicated in the designs and the dle angle of the tangent indicate, which includes it with the horizontal plane in a certain point. A further increase in the load of the material layer --1-- causes break, but slch the material around approximately 100% then already stretched. One knows thus the material as relatively tough descriptive, although it is relatively rigid within the first range of stress up to the Nachgtebigkeltsgrenze A and only small tendency points to the Strecknng. The material layer --3-- , like one has likewise the Fig. to infer it can do 2, a higher Elastizltätsmodul which means that the material with higher pressure - or tensile stress is less flexible, but this material layer reach very much rapidly its rupture stress, without the Elongation constitutes more than 2 to 10%, that means that the material is relative spröd and exhibits no Dehnungskapazltät during increased load, however its stiffness up to the point keeps, to the break effected. If now the Mehrsohichtverpackungsmaterial in accordance with Fig. 1 is used for the packing, then it shows particularly good stiffness characteristics, there both the outside layer--3--like also the internal layer --1-- and these are relatively rigid are combined with a relatively thick middle class --2--, which gives a check effect to the laminated material, i.e. a large moment at inertia, which causes high Starrhelt. If the material is exposed to Druckeinwlrknngen and impacts during shipping or at transport, the loads at the outside layers will increase suddenly and the mentioned loads below border the named A to remain so long, nothing special will happen on the material. If the impacts are so violent however that the load over the border A outside go and the border B to reach, then wlrd the material layer --1-- begin to give way, i.e. the modulus of elasticity for the adjusting Belasümgsbedingungen disappears and the material becomes tough and stretches. The danger of breaking the internal layer --1-- is small from there since the material possesses a very high StreckkapazitKt. The packing material loses naüirlieh a little from its stiffness, so for a long time the load lasts, there the modulus of elasticity of the layer--1--is presently/immediately reduced. As soon as however the pressure load stops, eßangL the material again its old stiffness, there the modulus of elasticity for the layer --1-- again achieves his normal value, if the pressure load under the value of the Elastizit£tsgrenze, which is named A, falls. Contained in cases, in which the compound packing material is used for packing FüllmateriaHen, the one gas, or which from e.g. the effect by air is to be protected, is favourable it to plan a further Plastiksehicht e.g. such from polyvinyl chloride, PP (nylon), Polyviuylidenchlorid (Saran) or Nitrilgumra| modified Acetylnitr lmethylacrylatcopolymere (cash). These plastic materials are arranged appropriately between the internal homogeneous plastic layer and the looking plastic material. In the case of use of the Mehrschichtverpackungsmaterlals according to invention it is thus possible to produce very rigid bags which in addition no liquids absorb and which have the characteristic that the Innenschlcht does not tear up, even if the sudden pressure load increase becomes very large.