CA2058101A1

CA2058101A1 - Sheet-like structures capable of intumescence, their production and their use

Info

Publication number: CA2058101A1
Application number: CA002058101A
Authority: CA
Inventors: Wulf Von Bonin; Ulrich Von Gizycki
Original assignee: Individual
Current assignee: Bayer AG
Priority date: 1990-12-22
Filing date: 1991-12-19
Publication date: 1992-06-23
Also published as: DE4041470A1; JPH04296543A; EP0492248A3; EP0492248A2

Abstract

Sheet-like structures capable of intumescence, their production and their use A b s t r a c t New sheet-like structures which are capable of intumes-cence contain a layer of granular intumescence material between two textile sheet-like structures which are stitched or sewn to one another.

Le A28 101 - Foreign countries

Description

2 ~

Sheet-like structures_capable of intumescence, their ~roduction and their use Sheet-like structures which are capable of intumescence, that is to say capable of thermal expansion, and if appropriate are flexible are of interest for the purpose of fire protection and for the production of construction elements.

It is known that structures which are capable of intumes-cence can be produced by coating textiles with intumes-cence materials. However, these have the disadvantagethat because of the of~en low flexibility of the coat-ings, these break and crumble, and that in~umescence active compounds can be employed for the production of such structures only with a binder and often also with a solvent, which is frequently undPsirable.

Sheet-like structures which are capable of intumescence have now been found, which are characterised in that they contain a layer of a granular intumescence agent between two textile sheet-like structures which are stitched or sewn to one another.

A process has also been found fox the production oE
optionally flexible intumescing sheet-like structures without using solvents or binders, which also leads to sheet-like structures ha~ing good mechanical properties Le A 28 101 - 1 -and is suitable in principle for all solids which intumesce.

The process according to the invention for the production of sheet-like structures which are capable of in~umes-cence is characterised in that a layer of a granularintume~cence agent is applied to a textile sheet-like structure, a second textile sheet-like structure is applied to this coating and th~ two sheet-like structures are then stitched or se~n to one another. A type of sandwich structure with a central layex which is capable of intumescence is thus formedO

Embodiments of the present invention in which at least one of the textile sheet-like structures is a non-woven of cellulosic material and expandable graphite or formulations containing e~pandable graphite have been used as the granular intumescence agen~ are of particular interest.

Glass fibres and/or mineral fibres can advantageously be integrated into the sheet-like structures according to the invention which are capable of intumescence, for example as a constituent of the tex~ile sheet-like structures or as an additional layer in woven ox non-woven form or as a loose concomitant ~ubstance in the layer of granular intumescence materLal.

Surprisingly, ~heet-like structure~ according to the invention can be highly fle~ible and mechanically Le A 28 101 - 2 -2 ~

resistan~, even if the intumescence ma~erial itself is rigid and crystalline. This is present in the finished product in an outstandingly fixed state, even if it has been employed in powder form or as granules. A
par~icularly good fixing is obtained if non-wovens are employed as the textile sheet-like structures and these are joined to one another by stitching.

It is furthermore suxprising that the stitching process also results in advantageous products w;ith thick layers of the intumescence agen~, in particular expandable gra-phite, the needles undergoing no damage even if the intumescence agent is employed in the fol~m of relatively large parPicles, for example particles having a diameter of 0.3 - 3 mm.

Possible textile sheet-like structures are, preferably, stitchable woven fabrics, kni~ted fabrics, loop fabrics, laid fabrics and in particular non-wovens. If products according to the invention are to be obtained by sewing, films and layers of foam can also be considered in~tead of the textile sheet-like structures. It is preferable to use textile sheet-like structures and to stitch these.
Multiple stitching can also be carried out, it being pos~ible for the sandwich structure formed to be doubled once or several times, if appropriate.

The textile sheet-like structure , preferably non-wovens, to be ~mployed as the starting material can have, for example, weights per unit area of 20 to 600 g/m2 or more, Le A 28 101 ~ 3 -2~8~

preferably 50 ~o 250 g/m2. They are preferably prestitched or if appropriate compacted by a binder. A prestitched non-woven can be handled more effectively and is therefore preferred. The fibre length (staple length) in the non-woven can be, for example, at leas~ 5 mm, preferably more than 20 mm.

Possible fibre ma~erials for the textile sheet-like structures are, pxeferably, cellulosic fibres, if appro-priate together with mineral fibres, or even mineral fibres as such. Other examples of the fibre material for the textile sheet-like structures are: wood (mechanical wood pulp), viscose staple fibres, viscose fibres and cellulose ester fibres, cotton, hemp, jute, sisal, coconut fibres, paper pulp, waste paper pulp, asbestos, customary glass fibres, extra fine glass fibres, rock wool, kaolin fibres, aluminium oxide fibres, carbon fibres, metal fibres and fibres and extra fine fibres based on aliphatic, araliphatic or aromatic, organic polymeric compounds, such as polyolefins, polydiolefins, polyamides, polyimides, polyvinyl alcohols, polyacrylates, poly(meth)acrylates, polyacrylonitriles and oxidation and/or pyrolysis products thereof, polyesters, polyethers, polyurethanes, polyureas, polysiloxanes, polyphospha~enes, proteins and polycarbodiimides.

Mixtures of various fibres can of cour~e also be present in the textile sheet-like structures.

Le A 28 101 - 4 -2 ~3 ~

Metal fibres, for example those of steel, high-grade steel, copper and/or silver, are also possible, preferably as a fibre mixture component.

The textile sheet-like structures to be employed can be identical or different.

In the production process according to the inven~ion for sheet-like structures which are capable of intumescence a procedure can be followed in which a dry layer, which can be sprinkled or is free-flowing, of an intumescence a~ent is preferably applied to an initial taxtile sheet-like structure, preferably a prestitched cellulose or cotton non-woven, which also additionally contains mineral fibres if appropriate. The intumescence agent can also be a mixture of different intumescence agents, an intumescence agent formulation or an intumescence formu-lation. Although application from a liquid phase, for example from an aqueous dispersion, or as a pasty formu-lation is possible, this is not preferred, since solvent-free working with intumescence material which can be sprinkled is technologically advantageous. Other fibrous structures, for example layers of mineral fibres, mineral fibre non-wovens, glass fabric or strands of carbon fibres, can also additionally be placed on the material or incorporated, if appropriate, befora, during or after application of the intumescence agent.

Preferred intumescence agents are graphites which are capable of thermal expansion or formulations containing 2 ~ 3 ~hese. Such graphites can have, for example, particle diameters of 0.1 to 5, preferably 0.4 to 3 mm. They are so-called intercalation compounds of graphite or so-called graphite salts. Those expandable graphites which are obtainable by treatment of graphites with nitric acid andtor sulphuric acid, if appropriate in fuming form, and if appropriate together with H2O2, and contain water, NO~
and/or SO~ as the blowing agent, are preferably used. Such graphites can be employed in the form in which they are formed, but also in neutralised form, for example neut-ralised with alkalis, ammonia or amines.

The expansion process of such expandable graphites, which can lead to volume increases of more than 100 %, starts from about 180C and has in general ended at about 600C.
However, the present invention no longer relates to the complete expansion of the expandable graphite or of other intumescence agents.

If appropria~e, the expandable graphites can also be employed together with other intumescence materials or with glass flakes, powders or fibres or other minerals, or in a form coated with a binder.

Examples of intumescence agents other than expandable graphites are micas which expand at temperatures up to 900C, preferably up to 600C, such as perlites, vermicu-lites or expandable borosilicates, aluminates, water-glass gels, water-containing alkali metal silicates and addition products of ammonia or amines on acid aluminium Le A 28 101 - 6 -phosphates, it also being possible, for example, for the la~ter to be used as the binder or coating agent for expandable graphite. Other intumescence agents can be, for example: ammonium and amine phosphates, ammonium and amine polyphosphates, such as phosphates ox polyphospho-nates of ethylenediamine and ammonia, of melamine ox of urea and its condensation products or combinations which, in addition to carbohydrates or pentae~ythritol and/or condensation products thereof andtor mel~mine, contain urea, dicyandiamide and/or methylol compounds thereof and if appropriate additionally also ammonium phosphates and sre known in principle as intumescence mixtures. Expand-able cork powder, expandable cereal grains, starch formulations and bark powder, if appropriate together with ammonium phosphate, are also possible, or powder of expandable polyurethane, such as are described, for example, in DE-A 3,302,416 and 3,302,417.

In addition to expandable graphites, expandable silicates which contain water and~or split off water are of par-ticular interest for the present invention.

In principle, all the granular intumescence materialswhich are capable of being sprinkled can be used. The particle sizes (average diameter) can be, for example, O.05 to 5 mm, preferably 0.3 to 3 mm.

The intumescence agents can be applied to the tex~ile sheet-like structure, for example, in an amount of 10 to 5,000 g/m2 or more, preferably 50 to 1,000 g/m~O They can Le A 28 101 - 7 -2 ~

be applied with a uniform layer thickness, but also in the form of stripes or a pa~tern. Certain part areas can remain non-sprinkled or be sprinkled with an increaRed amount of material. A procedure can then be followed in which a second web, which can preferably be stitched, of textile matarial is placed on the granular layer of intumescence material and the sandwich thus formed is sewn or preferably stitched. The stitching units which are customary for processlng non-wovens and have the mo~t diverse customary needle shapes, numbers, densities and arrangements are suitable for the stitching. The two textile sheet-like structures are preferably stitched ~hrough. However, only partial penetration of the needles into the textile sheet-like structure lying underneath is also possible.

As a result of the single or xepeated stitching which is preferably carried out over the entire surface, but if appropriate also over a part surface in the form of a pattern, the sandwich formed is compacted and the intu-mescence material present in the sandwich as the internallayer is bound in the sandwich so that it usually trickles out only insignificantly, even at fresh cut edges.

Although it is possible for optionally thermoplastic or reactive binders al80 to be u~ed, this is no~ preferred.

The sandwich thus prepared (= sheet-like structure according to the invention which is capable of Le A 28 101 - 8 -intumescence) can then be used or after-treated either directly or after suitable cutting. The after-treatment can be, for example, a biocidal, hydrophobic or oleophobic treatment, as well as colouring or printing.
It is advantageous for the freshly stitched sheet-like structure also to be ironed or flattened, if appropriate with steam being supplied, it being possible for tempexatures of up to 200C, preferably 80 to 150C, and pressures of, for example, up to 50 kg/cm2 or more, preferably 1 to 5 kg/cm2, to be used. During such ironing or flattening, it should be ensured that the intumescence agent in the sandwich expands only partly, if at all.

In special cases, the sheet-like structure according to the invention can be after-treated by brief heating to temperatures of, for example, between 150C and 300C, for example in a press, o that a certain expan~ion of its internal layer already occurs a~ this proce~s stage, that is to say before the sheet-like structure which is capable of intumescence is used as intended. This expan-sion can lead to stiffening of the material and/or to an even better binding of the intumescence materials and to a reduction in ~pecific gravity. In the case of expand-able graphite, a certain felting of the now partly expanded expandable graphite particles embedded in the structure also occurs, which further improves the binding of the expandable graphite particles to one another and to the total sheet-like structure without substantially limiting thé flexibility thereof.

Le A 28 101 - 9 -Sheet-like structures according to the invention which are capable of intumescence can al60 be produced in the form of several layers and/or stitched or sewn in the ~orm of several layers. They can be passed to other coating and impregnating processes, for example in order to be even further compacted on one or both sides over the entire area or in the form of a pattern, rendered waterproof, providèd with adhesive layers or strengthened or protected against mechanical stresses. They can also be used for the production of so-called prepregs, that is to say synthetic resin impregnates, which can be stored for minutes, days or months and can be hardened by heating, for example to 80 to 600C, preferably 100 to 300C, if appropriate while shaping.

The hardening reaction of the synthetic resin here can be combined, if appropriate, with the expansion of the sheet-like structure according to the invention serving as the base, by which procedure fibre-reinforced light-weight mouldings can be produced.

Possible synthetic resins are, in addition to thermo-plastics, such as polyolefins, polyvinyl aromatics, polyvinyl esters, polyacrylates, polyamides, polyesters, polyurethanes, polycarbonates and polyethers, also the customary thermosetting resin , for example un~aturated polyester resins, aminoplast resins, phenolic resins, epoxy resins, polyisocyanates, polyisocyanates in com-bination with polyols and/or epoxides, melamine rssins, cyanate resins and polyimide resins.

Le A 28 101 - 10 -2 ~ V ~

Sheet-like structures according to the invention which are capable of intu~escence and contain covering layers of thermoplastic material can also be used for the production of sandwich-like lightweight shaped articles by allowing the intumescence agent contained in the sheet-like structures according to the invention to expand at temperatures in the range from 200 to 2000C, preferably 300 to 900~C, while shaping. Such sandwich-like lightweight shaped articles, their production and their use form ~he subject matter of their own earlier patent application.

It is also possible for sheet like structures according to the in~ention, the covering layers of which consist of non-thermoplastic material, to be heated in moulds up to, for exalnple, 180 to 900C, preferably also 200 to 600C, to allow the intumescence agent to expand. The sheet-like structures according to the invention which are capable of intumescence can be cut in the desired manner before-hand and if appropriate also be introduced into the mould in several layers, if appropriate also in the form of windings around a mould core. During expansion, the mould, usually a metal mould of steel or aluminium, but also a ceramic mould, is then filled by the intumescence foam formed, so that a lightweight shaped article re-sults, the surfaces of which are formed by the pyrolysisproduct of the sheet-like structure which is capable of intumescence employed. As with other shaping processes, the release agents customary in industry can also he used Le A 28 101 here, for example those based on silicone, Teflon~ or boron nitride, and also starch solutions or dispersions of aluminium oxide, talc, cellulose or graphite.

In addition to the production of shaped articles, sheet-like structures according to the invention which are capable of intumescence can be employed, in particular, in the field of fire p~otection, specifically preventive fire protection. The material according to the inven~ion can be employed here in the form of sheet-like coverings, wallpapers, in the form of wrappings or cut sacks, seals, sheaths, adhesive tapes and fillings as protective agen~s which intumesce when flamed and are usually low-smoking.
In the event of a fire, penetration of the flames, heat, smoke and fire gases, for example through cable ducts, door leaves, wall elements, window joints, gaps, join~s and installation conduits, is then prevented. The sheet-like structures which are capable of intumescence, are preferably produced using expandable graphite or formulations containing expandable graphite, which in particular also contain glass fibres or mineral fibres and are provided with covering layers of predominantly cellulosic fibres are particularly suitable for the~e purposes. These hardly burn, especially if they also additionally contain phosphates, develop little smoke and expand effectively when exposed to flames.

Using the sheet-like structures according to the inven-tion, it is possible, for example, to line or glue roof surfaces, floors, suspended intermediate ceilings, door Le A 28 101 - 12 -2 ~
leaves, container walls and wall surfaces, to block wall ducts and cable bulkheads, to fill hollow spaces, to wind cables and pipelines and to fit windows, so that these are protected from fir~. Smoke gas barriers for, for example, air conditioning ducts or ven~ilation openings can also be produced by grid-like arrangements or a loose coil through which material can flow axiallyl which close due to expansion when exposed to flamesO Seals or joint fillings of sheet-like structures according to the invention whîch close due to expansion in the event of a fire are also possible. The sheet like structures according to the invention can also be u~ed as extinguishing blankets and for covering metal or oil fires.

If plastic pipes or thin-walled metal pipes are surrounded by coils of the sheet-like structures accord-ing to the invention and are optionally also protected by an outer shell, for example of sheet metal, such pipes are pressed against the coil area by the expansion acting inwards on exposure to flames and passage of the fire is thus prevented. As a result of the expansion of the sheet-like structures which takes place during heating or exposure to flames, they can also be used, especially if installed in several layers, to release safety switches, open or clo~e bulkheads, and operate levers.

The invention is explained by way of examples and pro~o-types below. The parts and percentages stated relate to the w~ight, unless stated otherwise.

Le A 28 101 - 13 -2 ~

Examples:

General To produce the sheet-like structures which are capable of intumescence, a stitching machine customary in industry (produced by Dilo XG, Type NDLP/6D) was used, in front of the intake of which a sprinkling bench was assembled, over which a textile web (non-woven web) was fed to the machine. About 80 cm before the intake, a second textile web (non-woven web) was fed via a roll to the bench and was placed flush on top of the first web and thus introduced into the stitching unit as a double layer.

A sprinkling device was assembled over ~he first textile web running over the bench, with the aid of which the web running over the feed bench was sprinkled over its en~ire surface.

A prestitched viscose staple fibre non-woven having a weight per unit area of 100 g/m2 with a titre of 1.7 dtex and a staple length of 40 mm was used as the underneath textile web (1) (textile sheet-like structure). Either the same material or a different material additionally described was used as the textile web ~2) fed in from ~he top. The flow rate was 1.2 m/minute. Ironing was carried out on a continuously operating flattening roll at 130C
under a pressing pressure of 3 bar over a residence time of 25 seconds.

Le A 28 101 - 14 -Example 1 Textile webs 1 and 2 were the same. 600 g/m2 of a commer-cially available china expandable graphite (NO~-SOx type, expansion capacity about 1,200 ~ by volume at 600C, average particle diameter 1~8 mm) were sprinkled on.
After the first passage through the stitching unit, the sheet-like structure formed was turned and stitched again from the other side. The sandwich formed was then ironed and was then capable of use. It was a highly flexible and mechanically stable sheet-like structure 2.7 mm thick, from which virtually no expandable graphite trickled out on cutting.

Example 2 The procedure was analogous to Example 1, but commercial-ly available SO~ expandable graphite of the same average particle size as in Example 1 was used. The amount sprinkled on was also increased to 1.1 kg/m2.

Example 3 40 parts of a 50 % strength aminoethanol solution in water were added to 100 parts of a 50 ~ strength solution of aluminium tris-phosphate in water, while stirring.
60 parts of the hot æolution of the aluminium phosphate salt thus prepared were stirred with 70 parts of NO2 expandable graphite. The slurry formed was dried and the Le A 28 101 - 15 2 ~
cake thus formed was comminuted and sieved to a particle diameter of 1.8 mm. An expandable graphite coated with 30 % of an aluminium phosphate binder was thus obtained.
The granular material thus prepared was sprinkled in an amount of 700 g/m2 onto the textile web (1), the web was stitched in a double layer with ~n identical textile web (2) and the structure was flattened.

Example 4 The sheet-like structure obtained according to Example 3 was doubled on the stitching unit. After ironing, it was 5 mm thick, highly flexible and mechanically stable. On cutting, virtually no intumescence material trickled out.

Example 5 The procedure was as in Example 3, but a glass non-woven having a weight per unit area of 300 g/m2 was also placed on the textile web (1) before the sprinkling process, so that the intumescence material sprinkled on lay on the glass non-woven, which became a constituent of the sandwich middle layer after ~titching analogou~ to Example 3. After ironing, a flexible sheet-liXe structure 2.8 mm thick was obtained.

Example 6 The procedure was analogous to Example 5, but the glass non-woven was placed on the web only after the expandable Le A 28 101 - 16 2~3~a 3 graphite formulation had been sprinkled on, 50 that the subsequent viscose staple fibre non-woven (textile web (2)) lay on this. During stitching, which was carried out three times, a stablP sheet-like structure was obtained, which, after ironing, had a thickness of 3 mm and was outstandingly suitable as an extin~uishing blanket.

Example 7 Before stitching and before being covered with the textile web (2), commercially available kaolin fibres shortened to a length of about 5 mm were first sprinkled onto the textile web (1) in an amount of 300 g/m2. The expandable graphite composition also used in Example 3 was sprinkled onto this layer in an amount of 700 g/m2, this was then covered with another layer of 300 g/m2 of the kaolin fibres and finally with the textile web (2) and the structure was stitched three times. A flexible, mechanically stable sheet-like structure 3.6 mm thick was obtained.

Example 8 The procedure was analogous to Example 3, but the expand-able graphite formulation (700 parts) was mixed homogen-eously with short glass fibres (MG glass fibres, Bayer AG, 700 parts) before being sprinkled on and the mixture was sprinkled on in an amount of 1,400 g/m2. The sheet-like structure (sandwich) obtained after double Le A 28 101 - 17 -2 ~ ~ ~3 stitching and subsequent ironing was mechanically stable and flexible and had a thickness of 3.1 mm.

Example 9 The procedure was analogous to Example 1. However, a mixture of equal parts of neutral e~hylenediamine ortho-phosphate and expandable graphite was sprinkled on in an amount of 1,000 g/m2. The stable sheet-like struc~ure ~hus obtained was highly flexible and had a thickness of 2.9 mm.

Example 10 The procedure was as in Example 5, but instead of the glass non-woven a glass fabric in a linen weave with a weight per unit area of 650 g/m2 was inserted. After ironing, a sheet-like structure which was flexible but less rea~ily deformable over its surface and was used as a fire protection covering and fire protection sub~trate for cableways was obtained.

Example 11 The procedure was as in Example 3, but instead of a viscose staple fibre non-woven, a cotton woven fabric (nettle) with a weight per unit area of 200 g/m2 was u~ed as the textile web (1). After double stitching on both sides and ironing, a mechanically resistant, flexible sheet-like structure which had a good bonding strength, Le A 28 101 - 18 -2 ~ ul J
so that virtually no expandable graphite material trickled out on cutting, was obtained.

ExamPle 12 The procedure was as in Example 6, but in each case a polyamide fibre non-woven having a weight per unit ~rea ~f 150 g/m2 was used as the ~extile webs 1 and 2.

Example 13 The procedure was as in Example 3, but a polypropylene fibre non-woven having a weight per unit area of 200 g~m2 was employed as the textile web (2). The ironing tempera-ture was reduced to 120C.

Example 14 The procedure was as in Example 2, but instead of the expandable graphite, a sodium silicate in the form of lS flakes and containing 12 ~ of water (Portil~ A, produced by Henkel) was used and the ironing temperature was reduced to 95C.

Example lS

The procedure was as in ~xample 14. However, the poly-propylene fibre non-woven described in Example 13 was used as the textile webs 1 and 2. The ironing temperature was also reduced to 95C.

Le A 28 101 - 19 -Example 16 The procedure was as in Example 2. However, an intimate mixture of the expandable graphite according to Example 3 t300 parts)~ the silicate according to Example 14 (200 parts) and the glass fibre according to Example 8 (200 parts) was employed as the intumescence material. A
flexible sheet-like structure with a good bonding of the materials and good mechanical stability was obtained. On cutting, virtually no intumescence material trickled out.

Example 17 A 50 ~ strength solution of aluminium tris phosphate in water was mixed intensively in an amount of 100 parts with 19 parts of ethylenediamine. The neutral 6alt slurry formed by this procedure was dried and the product was comminuted to particle sizes of between 0.18 and 1 mm. A
free-flowing powder which intumesces when exposed to flames was obtained. This was processed analogously to Example 2 instead of the expandable graphite. A mechanic-ally stable sandwich which had a good flexibility and can be used in the form of wrappings, sheaths or coverings to protect cables from the action of fire was obtained.

Example 18 (Testing of the intumescence) To test the ability to intumesce, squares each of edge length 3 cm were cut out of the sheet-like structures obtained according to Examples 1 to 17 and were placed on Le A 28 101 - 20 -f2 f3 b~
a str~tched metal ~ie~e of steel and introduced in~o a cabinet preheated to 600C. After 30 minutes, the samples were removed from the cabinet. In all cases, the original volume of the sheet-like structure had increased by more than 100 ~.

Example 19 Four layers of the sheet-like structure obtained according ~o Example 1 (about 34 g) were placed in a lidded box of finely perforated steel sheet 5 mm thick with internal dimensions of 10 x 10 x 2 cm. The box mould was then closed and placed in an oven, which reached 600C in the course of one hourO The mould was then removed from the oven and cooled and the shaped ar~icle formed was removed. It still had a weight of 23 g, corresponding to a specific gravity of 0.11 g/cm3. The parallelepiped thus produced had a covering layer of pyrolysed viscose staple and an indentation resistance, averaged over the area, of 9.5 kg/cm2, measured using a 0.25 cmZ steel measuring stamp.

Example 20 A layer of the non~woven sandwich obtained according to Example 2 was placed in the steel mould according to Example 19. The mollld was then closed and introduced into an oven preheated to 650~C. After one hour, the mould was removed from the oven, cooled and opened. A stable parallelepiped having an average specific gravity of Le A 28 101 - 21 -2 ~
0.05 g/cm3~ the surfaces of which consisted of viscose staple pyrolysis product, was obtained. The indentation resistance, averaged over the area, was 6.5 kg/cm2.
Such shaped articles have a foam-like ductile character.
They are suitable as soundproofing elements, can be machined, have high electrical conductivities and with exclusion of oxygen have high heat resistances of more than 2,000C.

Example 21 The procedure was analogous to Example 19, but two layers of the sheet-like structure from Example 3 were used. A
lightweight parallelepiped having an average specific gravity of 0.055 g/cm3 was obtained. This waæ introduced, together with a parallelepiped which had been obtained according to Example 20 and had not yet been heattreated, into an oven preheated to 700C, air having access to the inside thereof. After 6 hours, the parallelepipeds were removed. The weight loss of ~he parallelepiped according to Example 20 was more than 50 %, and it had virtually no further mechanical strength, while the weight 10BS of the parallelepiped according to Example 21, which was protected from oxidation by the binder, was only 9 % and this also showed no loss in respect of volume and mechanical properties.

Example 22 A piece of the sheet-like structure from Example 1 0.5 m2 Le A 28 101 - 22 -~ ~'3 in size was heated at 260C for three minutes in a heating press with a separation of 3 mm betw~en the two press plates which can be heated. The sheet-like structure which was modified in this way and was now 3 mm thick had a more textile-like handle than before and felt "fullerll, without having lost flexibility. Expansion by more than 100 % by volume also took place on exposure to flames.

Example 23 A wall element into which PVC pipes of 8 cm diameter were incorporated perpendicular to the surface was installed in a test oven. The pipe connections projecting 30 cm into the oven were enclosed, immediately before the installation wall, in a 10-layered, 15 cm wide coil of the sheet-like structures produced according to Examples 1, 2, 3, 4, 7, 8, 9, 12, 13, 14, 15 and 16, the last layer in each case being protected by a collar of 1 mm sheet steel.

The test oven constructed and operated in accordance with DIN 4102 was fired in accordance with the standard temperature curve. After an operatiny time of 30 minutes, all the PVC pipes had been pressed together due to the expansion of the coil positioned on the flame side and had become impermeable to the flame gases.

Le A 28 101 - 23 -.
.

2~3 Example 24 Steel pipes coiled several times in an S-shaped manner (wall thickness 3 mm, external diameter 4 cm) were each covered with a pipe having an internal diameter of~1.5 cm (internal wid~h) which had been cut and tailored from sheet-like structures according to the preceding ex-amples. The sheet-like structures from Examples 2, 5, 6, 7, 8, 9, 12, 13, 14, 15 and 16 were used in single-layer form. The sheet-like structure from Example 1 was used in two-layer form, and the shee~-like structure from Example 3 was used both in single-layer and in two-layer form. The pipes were then surrounded by a protective collar of sheet steel 0.2 mm thick at a distance of 1.5 cm and the structure thus obtained was heated at 500C for 30 minutes. A locking ~oin was then produced between the steel pipe and the ou~er protective collar by the expanded product foxmed, without shrink holes or hollow spaces occurring in the bonded piece.

The casings thus produced have soundproofing properties and remove the heat of the internal pipe in a slower manner (about 5 - 15 W/K m), which is desirable for exhaust pipes.

Example 25 1 m long and 20 cm wide strips of sheet-like structure~
obtained according to Examples 2 and 3 were in each case soaked to saturation on one of the two surfaces with a Le A 28 101 - 24 -2 ~

commercially available thermosetting epoxy resin mixture.
The strips were th~n placed in a mould, lined with aluminium foil~ for a pipe semi-cylindrical shell 1 m long and 1 cm thick. The mould was closed and-then heated at 300C for 5 minutes. It was then cooled and ~he resulting moulding laminated with aluminium film was removed from the mould. After removal of the aluminium foil, lightweight shaped shells having a specific gravity of less than 0.9 g/cm3, one surface of which consisted of a fibre-reinforced epoxy resin layer which imparted good mechanical strength, were present. In contrast, the inner surface which had not been impregnated with epoxy resin had a ductile character. These semi-cylindrical shells can be used as fire protection and insulating eIements for pipelines, and for the production of cable conduits.
When exposed to flames, the material still proved to be expandable, that is to say capable of intumescence, in the direction of the centre of the circle of its section, and was thus able to protect cable lying inside ayainst access by flames and further improve the insulating actions.

Example 26 The procedure was as in Example 25, but a hardening temperature of 680C was chosen and all the sheet-like structures according to Examples 1 - 10 were employed.
The oven temperature (680C) was reached in the course of 40 minutes and maintained for 10 minutes. The product was then cooled and removed from the mould. In all cases, a Le A 28 101 - 25 -~ 3~

stable pipe semi-cylindrical shell having a specific gravity of less than 0.9 g/cm3 and a hard mechanically stable surface layer where the synthetic re~in impregna-tion had previously been was obtained. No further expan-sion took place on exposure to flames.

Example 2Z

A sheet of commercially available polyphenylene sulphide (thickness 3 mm) was first placed in the mould according to Example 20, a sheet-like s~ruckure obtained according to Example 16 was then cut and placed in the mould, and an identical polyphenylene sulphide sheet was again placed in the mould. The mould was now closed and heated to 360C in an oven. When the temperature had been reached, the mould was removed from the oven. After cooling, a ligh~weight sandwich parallelepiped with polyphenylene sulphide covering layers was obtained. Such composite materials can be used in the construction of housings, loudspeaker boxes and vehicle bodies.

Example 28 The procedure was as in Example 27, but instead of polyphenylene sulphide, sheets of polypropylene wexe used, a sheet-like structure obtained according to Example 14 was employed and heating was carried out only up to 250~C. An insulating hard sandwich with polypropyl-ene covering layers and a core material of expanded~ilicate was obtained.

Le A 28 101 - 2S -2 ~ 3. ~3 ~

Example 29 Continuous joints 2 cm wide and 55 cm deep were milled into the 15 cm thick wall element of a tes~ oven accord-ing ~o Example 23, as well as circular holes of 10 cm S diameter and slots 20 x lO0 cm wide. These masonry break~
throughs were closed with sheet-like material from Examples 3, S, 6, 7 and 8 as follows:
The circular holes were filled and closed by 10 cm thick and 10 cm wide coils of ~he sandwich webs. The joints were closed by sections of the sheet-like structures folded or rolled several times, and the slots were blocked as homogeneously as possible by sandwich material crumpled like, for example, newspaper with no specific order, this being secured against falling out by a piece lS of stretched metal grid positioned on the outside. In a fire test in which firing was carried out using the standard temperature curve in accordance with DIN 4102, all the openings were closed even after a burning tLme of 3 hours.

Example 30 The procedure was as in Example 1, but instead of expand-able graphite, a commercially available vermiculite (thermally expandable mica) of average largest particle diameter of 3 mm was used.

The non-woven sandwich obtained was mechanically stable, only insigni~icant intumescence material trickled out at Le A 28 101 - 27 -2 ~
the cut points, and the structure was completely flexible and cQuld be rolled and folded; on exposure to flame, it foamed vigorously.

A strip of the sandwich forced U-shaped into a 1 cm wide joint between two concrete plates closed the joint on exposure to flames.

Example 31 The procedure was as in Example 1, but instead of the expandable graphite a mixture of equal parts of the expandable graphite and the vermiculite used in Example 30 was used. The resulting flexible sandwich material could be used for fire protection purposes analogously to Example 30 and for the production of shaped articles analogously to Example 20.

Example 32 100 parts of a 50 % strength solution of a reaction product of one mol of aluminium hydroxide with three mols of H3PO4 in water were neutralised with 38 parts of ethanolamine. The water was then removed in vacuo at 80C. 30 parts of the highly viscous material thus obtained, which is capable of intumescence, were needed at 80C with 70 parts of the vermiculite used in Example 30. After cooling to 22C, this gave a material mixture which was capable of being sprinkled and in which the vermiculite was coated with the binder. This material Le A 28 101 - 28 -2~J~J~

was processed to a non-woven sandwich analogously to Example 1 with an amount deposited of 1000 g/m2.

This sandwich could be used analogously to Example 30 for fire protection purposes and analogously to Example 20 S for production of mouldings.

Le A 28 101 - 29 -

Claims

1. A sheet-like structure which is capable of intumescence, which contains a layer of a granular intumescence agent between two textile sheet-like structures which are stitched or sewn to one another.

2. A process for the production of a sheet-like structure which is capable of intumescence, in which a layer of a granular intumescence agent is applied to a textile sheet-like structure, a second textile sheet-like structure is applied to this coating and the two sheet-like structures are then stitched or sewn to one another.

3. The process of Claim 2, in which at least one of the textile sheet-like structures is a non-woven cellulosic material, and expandable graphite or formulations containing expandable graphite are used as the granular intumescence agent.

4. The process of Claim 2, in which glass fibres and/or mineral fibres are integrated as a constituent of the textile sheet-like structures or as an additional layer in woven or non-woven form or as a loose concomitant substance in the layer of granular intumescence material.

5. The process of Claim 2, in which non-wovens having a weight per unit area of 20 to 600 g/m2 Le A 28 101-US - 30 -are employed as the textile sheet-like structures and these are joined to one another by stitching.

6. The process of Claim 2, in which the fibre materials used for the textile sheet-like structures are cellulosic fibres, if appropriate together with mineral fibres or mineral fibres as such, wood, mechanical woo d pulp, viscose staple fibres, viscose fibres, cellulose ester fibres, cotton, hemp, jute, sisal, coconut fibres, paper pulp, waste paper pulp, asbestos, glass fibres, extra fine glass fibres, rock wool, kaolin fibres, aluminium oxide fibres, carbon fibres, metal fibres, fibres and extra fine fibres based on aliphatic, araliphatic or aromatic, organic polymeric compounds and/or metal fibres.

7. The process of Claim 2, in which the intumescence agents used are expandable mica, expandable borosilicates, aluminates, water-glass gels, water-containing alkali metal silicates, addition prod-ucts of ammonia or amines on acid aluminium phosphates, ammonium phosphates, amine phosphates, ammonium polyphos-phates, amine polyphosphates, expandable cork powder, expandable cereal grains, starch formulations, bark powder and/or powder of expandable polyurethane.

8. The method of using the sheet-like structures of Claim 1 or produced according to Claim 2 which are capable of intumescence for the production of synthetic resin impregnates which can be stored and can be hardened by heating to 80 to 600°C, if appropriate while shaping.

Le A 28 101 - 31 -

9. The method of using the sheet-like structures of Claim 1 or produced according to Claim 2 which are capable -of intumescence and having covering layers of thermoplastic material for the production of sandwich-like lightweight shaped articles by allowing the intumescence agent contained in the sheet-like structures to expand at temperatures in the range from 200 to 2000°C, while shaping.

10. The method of using the sheet-like structures of Claim 1 or produced according to Claim 2 for the pro-duction of lightweight shaped articles, wherein the sheet-like structures which are capable of intumescence and have covering layers of non-thermoplastic material are heated up to 180 to 900°C in moulds, during which the intumescence agent is allowed to expand.

Le A 28 101 - 32 -