DE2423487A1 - LAYER MATERIAL FOR ROOF STRUCTURES AND METHODS FOR ITS MANUFACTURING - Google Patents

Description

PATENT LAWYERS

Dlpl.-lng. P. WIRTH Dr. V. SCHMIED-KOWARZIK DlpL-lng. G. DANNENBERG Dr. P. WEINHOLD Dr. D. GUDEL

281134 β FRANKFURT AM MAIN

TELEF ^{N C061D} _{2870] 4} GR. ESCHENHEIMER STBASSE 39

SK / SK 73T121

Koppers Company, Inc. 1450 Koppers Building Pittsburgh, Pa. 15219 / USA

Layered material for roof structures and processes for its manufacture

The present invention relates generally to a sheet material "from a layer of polystyrene foam'und'-onef Layers of lightweight cementitious preparation integrally bonded together; it relates in particular on built-up roof structures

Composite roof structures used to be made from alternating Layers of bituminous material and felt are formed, which are put together in place and over a sub-layer were applied. The underlayer was usually made of lightweight concrete, such as one made of Portland; cement, water, and one Lightweight aggregate (aggregate) such as vermiculite or perlite, prepared slurry that has been allowed to harden.

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Polystyrene foam sheets of substantial width, length and thickness are commercially available from various manufacturers. Such a polystyrene foam sheet is ideal roof insulation. Their closed cell structure excludes excessive moisture the end; for example, the water absorption of a foamed

2 polystyrene of 0.02 g / ccrr serves only 290 g of water per m after 48 hours of immersion, and the water vapor permeability is only 0.6-0.8'perm-in. The plate keeps the thermoregulation permanently low; For example, foamed polystyrene with a density of 0.02 g / ccm has a k-factor of 0.230 at -4.4 C. average Temperature, which reduces the harmful blistering of composite roofs. The lightweight polystyrene foam panels are easy to handle and reduce the load on the roof.

One problem with using expanded polystyrene for Roof structures is that the bituminous material used in composite roofing materials attacks the polystyrene, which is why the latter must be protected from such an attack. One solution to this problem was found in US Pat 3 094 447 proposed. Another solution is to use a top insulation made of expanded polystyrene sheets Layer of lightweight concrete, usually of the vermiculite or perlite type, to be poured. This latter construction provides the against an attack on the roofing bitumen materials by the polystyrene necessary protection, but the solution led to one another problem by adding the portland cement slurry or the

the
The concrete obtained does not adhere well to the foamed polystyrene plate and a weak interfacial surface between the plate made of foamed polystyrene and the upper cast layer made of lightweight concrete

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connection exists.

It is well known in the roofing industry how important it is that all components of the "roof structure system" are fully interconnected are. 3the loss of bond between the main building structure and the roof structure, between the latter and the Insulation or between this and the assembled roof can easily be the main factor in failure of the entire con-

(-structure)

be construction. Roof truss / »insulation and roof covering must act as an integral unit when they are exposed to the stresses developed by changes in heat that affect the service life of the roof constantly appear, should prove itself.

It has now been found that a low density cementitious preparation of an inorganic hydraulic cementitious Binder, expanded polystyrene particles and a homogenizing agent for maintaining the expanded polystyrene particles in uniform dispersion in the aqueous slurry until it hardens and bonds the pearls with the hydraulic binder, in a surprising way binds itself to a sheet of polystyrene foam. So, using a layer of a polystyrene foam sheet a fully integrated, joined together Roof system are produced.

The accompanying drawing is a perspective view of an embodiment of a roof system according to the invention in which certain parts were disclosed.

The roof system shown in the drawing includes roof purlins. 21, a pad or base 23, a lightweight concrete mass

C-

25, a sheet of expanded polystyrene 27, another

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Lightweight concrete mass 29, a bituminous layer 31 and a gravel layer 33.

("purlins")
The purlins are common structural parts on a building that are used to support the base 23. The pad or
Base 23 is made of any suitable material, ujie wood, metal usuj. It can have the shape for pouring the concrete layer 25.

According to the invention, the monolithic layers of concrete compound 25 and 29 comprise a homogeneous matrix of cement and expanded beads of a thermoplastic material, preferably expanded polystyrene beads, which are uniformly dispersed through the matrix and bound to the cement. A typical inventive
Concrete mix comprises 0.5-1 parts by weight of a homogenizing agent, 3 parts by weight of expanded thermoplastic beads and 50-90 parts by weight of hydrated Portland cement.

The usual portland cements, gypsum products (tuie alabaster gypsum), calcium aluminate cements,
High alumina cements and magnesia cements or combinations thereof have been used.

Expanded thermoplastic beads are commercially available, expanded beads made of polystyrene being preferably used. These polystyrene beads are expanded by heating, whereupon the blowing agent contained in the beads causes them to expand to 10 to 30 times their original size. The density of the expanded polystyrene beads is
about 0.016 g / cc.

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A description of the various surfactants and through leading synergists who are capable of making the slurry To keep them homogeneous are described in US Pat. No. 3,272,765.

The big differences in the density of the various components of the concrete compound, especially between the expanded polystyrene beads, cement and water, causes these separate in slurry form and tend to agglomerate. Homogenizing agents such as those described in U.S. patents 3,272,765 and 3,214,393 disperse the expanded Keep polystyrene beads uniform in the slurry, too maintain a uniform dispersion until the slurry hardens into the solid, state and create the bond to / ischen the expanded polystyrene beads with the cement.

The plates 27 made of polystyrene foam which can be used according to the invention can have a density between 0.16-0.32 g / ccn, with the Thickness can vary from 2.5-15 cm or more. According to the information in "Modern Plastic". Duni 1960, Vol. 37, No. 10, page 87 ff., · Such a material is available from various manufacturers. The sheets can be made by foaming the expandable polystyrene produced by the action of heat ", the Expansion is partially withheld. The foils or sheets can be bought in different widths and lengths.

The layer 21 of the bituminous material that forms the top surface the concrete mass 19 covered in the composite is the weather exposed, is waterproof and can be made into a tar compound dissolved rubber, asphalt compounds, bituminous emulsions

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sions, mixtures of aromatics and coal tar pitch usuj. exist. The bituminous layer 31 completes the concrete mass. It can be spread out and is flowable like this for sealing Minor cracks are necessary, which occur in the concrete mass due to a settling of the building structure 'during the service life of the integrated structure. Optionally, this layer of bituminous material can be different from that in usual roofs that are joined together, i.e. it can made of layers of felt, i.e. cellulos ischetn, asbestos or glass felt exist, which are connected together and to the surface of the concrete mass 19 by means of hot applied asphalt or coal tar are.

A conventional gravel layer 33 with the values established in the US standard test ASTR D-1863 for UU light resistance can be used for Protection of the bituminous layer 31 from any degradation by sunlight can be used.

During the manufacture of the integrated roof system, a slurry, preferably made of port land cement, expanded polystyrene beads, a homogenizing agent and water. A preferred composition is in U.S. Patent 3 272 765.

A typical formulation can consist of 50-9 parts by weight of Portland cement, 3 parts by weight of expanded polystyrene beads, 0.5-1 part of homogenizing agent and 35-45 parts of water. The parts become a homogeneous suspension with a mixed to such a consistency that it is easy to flow.

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Then the slurry is drawn through an ordinary pumping and piping line pumped onto the roof and laid over the base 23 in any desired thickness, the thickness preferably being at least ebiua 6. mm and the base 23 can give the shape. Then the slurry is leveled to form an even surface to accommodate the layers of υ expanded polystyrene

("screecing"). Immediately after leveling / the concrete layer 23

The polystyrene foam sheet 27 is placed in the right place the wet concrete preparation laid. Having a reasonable area

(Leveling or leveling plank.) Was covered with the polystyrene foam panels, planksY placed on the slabs, and the final top layer 29 of the lightweight concrete compound is poured on. This layer can be from any desired finished thickness; however, this thickness is usually at least 5 cm. The lightweight concrete compound binds in about 4-6 hours. Thereafter, the top layer 29 with the bituminous Layer 31 are covered. The gravel layer 33 can in the usual way for joined roof systems on the bituminous Layer 31 can be laid.

In a preferred roof system, the bituminous material is poured over the solid concrete layer 29, preferably in a "thickness of about 1.25 cm." The bituminous material is preferably ^{heated to about 205 °} C. so that it has the correct viscosity The hot bitumen material in contact with the top surface of the solid concrete melts and disintegrates the expanded polystyrene beads on the surface of the solid concrete mass, but does not attack the expanded polystyrene beads below the surface.

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The bituminous material fills the cavities and connects mechanically with the concrete layer 29 after cooling. This ensures the unit of bituminous material and the Surface of the solid mass made of lightweight concrete. Then gravel 31 or a similar material is made over the layer given to hot bitumen material. This application of gravel and bituminous material on cement-like coffers with a light weight is described in U.S. Patent 3,667,878.

The above description related to a new insulating roof truss material in which all layers are integrally connected are. The mechanical bond between the lightweight concrete surface and the bituminous material was described.

Surprisingly, a strong bond also develops between the plate made of polystyrene foam and the lightweight concrete mass; this bond occurs on both the top and bottom surfaces of the expanded polystyrene sheet. She usually is stronger than the cohesive forces within the polystyrene foam sheet. The reason for this strong bond is unknown to it however, it is believed that the properties of the cementitious Preparation that takes it from slurry to solid state keep homogeneous, even when bonding the plate to the cementitious Preparation play a role. When a hardened lightweight concrete preparation breaks, it was found that the Rupture point practically all of the individual polystyrene foam particles in this section were split, resulting in a. Part of the polystyrene particle embedded in one fracture point and left the other part embedded in the other fracture point. The same tough one There also appears to be a bond between the lightweight concrete compound and the

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Polystyrene foam board to exist on the intermediate surfaces of the two. In laboratory tests, sheet materials were made up of a sheet of polystyrene foam sheet and a sheet of the lightweight concrete compound, which were manufactured in accordance with the invention, subjected to loads up to failure; included the breaking occurred within the polystyrene foam sheet and not at the interface between the concrete preparation and expanded polystyrene board.

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Claims (4)

Claims 1, - layer material, im. essentially consisting of a layer of over-foamed Polystyrene and a layer of a light cementitious preparation from an inorganic hydraulic, cementitious Binder, expanded particles of a thermoplastic polymer and a homogenizing agent to ensure a uniform Maintain dispersion of the beads in the slurry and create a bond with the pearls and the binder. 2.- Layer material according to claim 1, characterized in that the cement-like preparation with a slight Geu / icht from (a) 0.5-1 Geu /.- part of a homogenizing agent ) (b) 3 parts by weight of expanded thermoplastic beads Materials; and (c) 50-90 Geuj. -Share Portland cement and by mixing the above ingredients with etica 35-45 Parts by weight of water to form a slurry for application is formed on the layer of expanded polystyrene. 3, - Integrated, insulated and weatherproof roof or Roof system, consisting of (a) a base or record, (B) a first layer of a lightweight concrete preparation, the one homogeneous matrix of an inorganic cementitious binder and expanded beads of a thermoplastic, attached to the binder bound material is; (c) a polystyrene foam layer, 09 884/0883 (d) another layer of the lightweight concrete compound and (e) a layer of bituminous material on top of the latter Layer of lightweight concrete compound, luobei the layers to form an integral structural unit are connected and the bond is characterized by the absence of additional adhesive material between the layers is. 4. Roof system according to claim 3, characterized in that the bituminous layer can comprise at least one layer of felt. 5J method for producing a roof or roof system according to claim 3 and 4, on a base or pad, thereby marked that one (a) a slurry of cementitious material, expanded Applying beads of a thermoplastic material and water as a first layer to the substrate; (b) the first layer of the slurry with a plate or foamed polystyrene film covering as a second layer; (c) applying another layer of the slurry to the expanded polystyrene sheet as a third layer; and (d) after the slurry of the third layer has settled into a solid mass, the fourth layer is a bituminous material onto the surface of the third layer to disintegrate the expanded thermoplastic beads onto the surface of the third layer, whereby the fourth layer of bitumen 40988 A / 0883 minous material mechanically bound to the surface of this mass and the mass obtained from the slurry the polystyrene foam sheet is bound. The patent attorney: 409884/0883