WO2007003608A1

WO2007003608A1 - Liquid tank consisting of a melamine/formaldehyde foam

Info

Publication number: WO2007003608A1
Application number: PCT/EP2006/063760
Authority: WO
Inventors: Klaus Hahn; Armin Alteheld; Christof MÖCK; Bernhard Vath; Volker Frenz
Original assignee: Basf Aktiengesellschaft
Priority date: 2005-07-06
Filing date: 2006-06-30
Publication date: 2007-01-11
Also published as: DE102005031851A1

Abstract

The invention relates to a liquid tank consisting of an open-cell foam based on a melamine/formaldehyde condensation product with a metal or plastic coating, and to the use thereof as a fuel tank, an oil tank, or a tank container for tankers, tank trailers or tank ships, especially for storing or transporting liquid hazardous substances, environmentally damaging substances or cryogenic liquids.

Description

Liquid storage of melamine / formaldehyde foam

description

The invention relates to a liquid storage of an open-cell foam based on a melamine / formaldehyde condensation product with a Ummante- treatment of metal or plastic, and use as a fuel tank, oil tank, tank container for tankers, tank trailers or tankers, especially for the storage or transport of liquid hazardous substances , environmentally hazardous substances or cryogenic liquids.

Open-cell foams based on a melamine / formaldehyde condensation product are known for various heat and sound insulation applications in buildings and vehicles, as well as insulating and shock-absorbing packaging material. The open-cell structure allows the recording and storage of suitable cleaning abrasive and polishing agent when used as a cleaning grinding and polishing sponge (WO 01/94436).

From German Utility Model 94 19 804, the use of open-cell foams of duromer plastics, eg. B. based on a melamine / form aldehyde condensation product, known as a sound absorption element for a cylinder head cover. In order to prevent the surface of the foam is added by oils or fats, it is proposed to coat this with an oil-resistant plastic film or non-woven fabric.

US 5,457,136 describes crosslinked gelatin foams for thermal insulation, in particular of pipes. For this purpose, the aqueous gelatin with glutaraldehyde as a crosslinker and optionally a secondary crosslinking agent, for. B foamed a melamine / formaldehyde condensation product and dried.

EP-A 1 498 680 describes a cooling and holding battery of melamine / formaldehyde foam, the cell pores of which are completely or partially filled with a flowable heat carrier and which may be a jacket, for example of a polyolefin foil.

Tank containers for the transport of hazardous substances are often equipped with a multi-layer shell and a division of the tank into several chambers to reduce the amount of leaking dangerous goods in accidents (US 2005/0115621). In addition, the splitting of the tank into several chambers or the insertion of sheets or ribs inside the tank counteracts an excessive movement of the liquid in the tank and the associated shift of the center of gravity. Object of the present invention was to remedy the aforementioned disadvantages and provide a liquid storage, which is leak-proof and binds the liquid even at low level in the interior, so that the center of gravity does not shift during transport.

Accordingly, the above-described liquid storage has been found.

As open-cell foams are preferably elastic foams based on a melamine / formaldehyde condensation product having a specific gravity of 5 to 100 g / l, in particular from 8 to 20 g / l used. The cell count is usually in the range of 50 to 300 cells / 25 mm. The tensile strength is preferably in the range of 100 to 150 kPa and the elongation at break in the range of 8 to 20%.

For the preparation according to EP-A 071 672 or EP-A 037 470 a highly concentrated propellant-containing solution or dispersion of a melamine-formaldehyde precondensate can be foamed and cured with hot air, water vapor or by microwave irradiation. Such foams are commercially available under the name Basotect® from BASF Aktiengesellschaft.

The molar ratio of melamine / formadehyde is generally in the range of 1: 1 to 1: 5. For the production of particularly low-formaldehyde foams, the molar ratio in the range of 1: 1, 3 to 1: 1, 8 is selected and a sulfite group-free precondensate used, such as. B described in WO 01/94436.

In order to improve the performance properties, the foams can then be tempered and pressed. The foams can be cut to the desired shape and thickness and laminated on one or both sides with cover layers. In the case of the jacket, a cover layer is usually not necessary.

The jacket of the liquid reservoir preferably consists of a torsionally rigid material, such as metal or plastic, in particular of steel, aluminum or fiber-reinforced plastic. Suitable plastics are polyethylene, polypropylene, epoxy or polyester resins, which may optionally be reinforced with carbon or glass fibers, wovens or mats.

The sheath may additionally comprise a heat-insulating sheath layer, for. As polyurethane foam and / or fluid barrier layer, such as plastic films. The Ummantellung serves the stability and protection of the liquid storage. The cross section is usually round or oval. It can be mounted as a storage tank on concrete or metal racks or placed on road or rail vehicles, trailers or in containers or ships or installed. For stability reasons larger tanks with a content of z. B. more than 5 m ³ additionally be divided into several chambers. In this case, not every chamber or not the entire volume of the sheath must be filled with the open-cell foam. However, preferably 50 to 100% by volume, in particular 80 to 95% by volume, of the volume available for storage or transport is filled with the open-cell foam.

Owing to the low density of the foam and the open-celledness, more than 95% by volume, in particular more than 98% by volume, of the tank region filled with the open-cell foam is available for receiving the liquid.

The liquid storage device according to the invention can be used for storing various liquids and is suitable due to the extensive chemical resistance of the melamine / formaldehyde condensate in particular as a fuel tank, oil tank, tank container for tankers, tank trailers or tankers.

Further uses of the liquid reservoirs according to the invention are containers for brake, washing, cooling or hydraulic fluids which are used, for example, in air conditioners or in the automotive sector, or liquid reservoirs which are exposed to strong accelerations, for example ink reservoirs in inkjet printers.

The liquid penetrates into the open-cell foam and prevents unwanted leakage. Therefore, even if the casing is damaged, the liquid remains largely bound in the pores of the foam and leakage is prevented. Liquid hazardous substances or substances hazardous to the environment are kept inside the foam in the event of a leak in the outer skin of the tank and do not run out. Thus, for example, an oil spill in a tanker accident can be avoided.

Even with incomplete filling of the tank prevents the open-celled

Foam a shift of the center of gravity of the liquid reservoir during transport by vibrations of the liquid in the case of strong and sudden changes in movement, such as heavy braking or cornering.

The filling and Entlehrung of the tank can be done by means of pressure or vacuum pum. In this case, the liquid held in the pores of the open-cell foam is replaced by air or a gas. As a rule, an overpressure or underpressure in relation to the ambient pressure in the range of 0.01 to 10 bar, preferably in the range of 0.1 to 1 bar, is sufficient to fill or to empty the tank. Due to the elasticity of the open-cell foam, the cells of the foam are not broken here. Depending on whether a higher storage capacity or faster and complete emptying of the liquid reservoir is desired, the capillary forces can be adjusted by changing the cell size or the hydrophobicity or hydrophilicity of the open-cell foam targeted. Depending on the chemical nature and viscosity of the liquid to be stored, the surface of the cell structure of the open-cell foam can be completely or partially coated with a hydrophobing agent, for example an aqueous emulsion of a silicone or fluoroalkyl ester.

Due to the elasticity of the open-cell foam, this can be simple

Be inserted into already prefabricated tanks. Smaller containers can also be filled with foam puffs.

Even at low temperatures, for example below -80 ⁰ C, the foam remains elastic. Damage caused by embrittlement does not occur. The liquid spoke according to the invention is therefore also suitable for receiving cryogenic liquids, for example liquid air, nitrogen, hydrogen, noble gases, such as argon, neon or helium, and hydrocarbons, such as propylene or methane.

The liquid storage is therefore particularly suitable for the storage or transport of liquid hazardous substances, environmentally hazardous substances or cryogenic liquids.

Example:

Make a liquid store:

An open-celled melamine / formaldehyde foam with a density of about 10 kg / m ³ (Basotect® BASF Aktiengesellschaft) was cut into a cylinder with a diameter of 100 mm and a height of about 100 mm (volume 700 ml) and in a cylindrical glass apparatus with a diameter of 99.2 mm and 1, 5 I capacity fit. The glass apparatus was equipped at the upper end with a supply and exhaust air line of 5 mm diameter for filling and with a spout at the lower end with a diameter of 9.2 mm.

I. Filling and emptying a liquid reservoir with water

A volume of 700 ml of water was introduced into the apparatus through the filler neck, which was immediately taken up by the dry foam. The overpressure of the compressed air supply line was set to a value of 0.01 bar and the drain cock opened with the exhaust air line open. When the drain cock was opened, water with a volume of 500 ml flowed out of the outlet within 70 seconds. 700 ml of water were again added to the now moistened foam in the apparatus. By opening the outlet tap, the apparatus was removed at atmospheric pressure within 75 s, a volume of 620 ml of water. There remained 80 ml of the added water in the foam. This volume was taken by applying an overpressure of the compressed air line of 0.2 bar and open exhaust pipe of the apparatus within 10 s.

700 ml of water were again added to the humidified apparatus. By means of the compressed air line, an overpressure of 0.01 bar was set in the vessel with the exhaust air line closed. When the tap was opened, a volume of 700 ml ran out of the apparatus within 200 s.

700 ml of water were again added to the humidified apparatus. By means of a water jet pump, a negative pressure of 0.21 bar was set in the outlet of the apparatus with the exhaust air line closed. When the tap was opened, a volume of 700 ml was released from the apparatus within 50 seconds.

II. Infilling and draining a fluid reservoir with gasoline

A volume of 850 ml of gasoline (60/40) was filled into the apparatus via the filler neck. The inclusion of the gasoline in the dry foam was carried out within 12 s. When the outlet tap was opened under atmospheric pressure, gasoline with a volume of 750 ml flowed out of the outlet within 45 seconds.

850 ml of gasoline were again added to the no longer dry foam in the apparatus. By means of a water jet pump, a negative pressure of 0.21 bar was set in the outlet of the apparatus with the exhaust air line closed. When the drain cock was opened, gasoline with a volume of 850 ml ran out of the equipment within 30 seconds.

Claims

claims

1. Liquid storage of an open-cell foam based on a MeI- amine / formaldehyde condensation product with a sheath made of metal or plastic.

2. Liquid reservoir according to claim 1, characterized in that the open-cell foam has a specific density in the range of 5 to 100 g / l.

3. Liquid reservoir according to claim 1 or 2, characterized in that the open-cell foam of a melamine / formaldehyde condensation product having a molar ratio of melamine / formadehyde in the range of 1: 1 and 1: 5 was prepared.

4. Liquid reservoir according to one of claims 1 to 3, characterized in that the jacket consists of steel, aluminum or fiber-reinforced plastic.

5. Liquid reservoir according to one of claims 1 to 4, characterized in that the sheath additionally contains a heat-insulating sheath layer and / or liquid barrier layer.

6. Use of the liquid reservoir according to one of claims 1 to 5 as a fuel tank, oil tank, tank container for tankers, tank trailers or

Tankers.

7. Use of the liquid reservoir according to one of claims 1 to 5 as a container for brake, washing, cooling or hydraulic fluids.

8. Use of the liquid reservoir according to one of claims 1 to 5 for the storage or transport of liquid hazardous substances, environmentally hazardous substances or cryogenic liquids.