DE102008022065A1 - Material used for screening a building or parts of a building from electromagnetic fields and/or for heat insulation purposes comprises a porous matrix partly made from a magnetizable material - Google Patents

Abstract

Material comprises a porous matrix partly made from a magnetizable material. An independent claim is also included for a building material containing the above material.

Description

Of the Protecting rooms inside buildings from electromagnetic Fields, such as those caused by power lines, wireless Communication, radio links, high-frequency positioning systems and other electrotechnical applications arise, always attained greater importance. In particular, rooms with sensitive electrical equipment, such as under in information-processing sectors, healthcare, in safety-relevant areas as well as in accredited testing laboratories encountered, require reliable protection against interference and information misdirections. It plays, depending on the local Conditions and requirements, the shielding of the wall or floor area, the roof and ceiling area of the rooms or buildings and cable ducts, or several of these areas at the same time, a central role. In many cases, the need exists at the same time a good thermal insulation of said areas, which results for reasons of energy efficiency.

From the publication WO 02/13311 For example, a material having thermal insulating properties is known which also has shielding properties against electromagnetic fields. It is an absorber granulate whose porous glass and / or ceramic granules are coated with an electrically conductive material, and which can be applied together with a binder as a plaster on masonry.

The publication DE 4439739 discloses a thermal barrier panel containing magnetic tape pieces in a resin matrix and thereby also having electromagnetic radiation shielding properties.

The known shields have the disadvantage that they after the Building a room or building on walls, Floors, ceilings and / or cable-carrying shafts must be attached in further steps. It is desirable to do the work of building Buildings or individual rooms with good thermal insulation and at the same time effective shielding of electromagnetic Reduce fields.

Of the The invention is therefore based on the object of specifying a material, the next to a sufficient for building materials mechanical Strength also insulating properties and in addition to shielding properties has electromagnetic fields. In addition, supposedly on-site processing of said product with the known Procedure be possible.

According to the invention this task by a material according to the independent claim 1 solved.

Of the Proportion of the magnetizable material on the porous matrix is preferably more than 80% by weight. The porosity of the material is preferably between 40 and 90 Volume-%. The porous matrix is preferably at least partly of a conductive and / or semiconductive material. Possibly The matrix may additionally contain stabilizers which contribute to the mechanical strength of the material. The matrix material consists preferably at least partially made of ferrite, since ferrite is a small Has thermal conductivity. Among the ferrite materials Particularly preferred are manganese-zinc ferrite, magnesium-zinc ferrite and / or nickel-zinc ferrite.

Under a magnetizable material should be understood here as a material whose relative permeability μ, at a Frequency of 10 kHz and measured at a modulation of 0.25 mT, greater than 10, preferably larger is greater than 100, more preferably greater than 500.

The magnetizable material is preferably a soft magnetic material, more preferably, a soft magnetic material having a coercive force less than 1000 A / m, more preferably a soft magnetic material with a coercive force of less than 150 A / m.

The Production of the porous matrix takes place z. B. by drying an aqueous suspension of ferrite raw materials - at a manganese-zinc ferrite, for example, from the raw materials iron oxide, Zinc oxide and manganese oxide - under suitable conditions, preferably under hydrothermal conditions. The suspension is in a converted to porous solid. By a subsequent ceramic firing process results in an inventive Material consisting of a porous ferrite matrix. Out this material existing components can in a desired Form, for example in plate or brick form, are produced or after the firing process, for example by cutting or Sawing, be brought into the desired shape. The components thus obtained have sufficient strength, around them with known methods, such as walls or in Dry construction, to be able to process on site. Required for thermal insulation materials Properties, also with regard to pressure resistance and fire protection, are complied with by these components.

Preference is given to component thicknesses of the thermal insulation material between 1 and 50 cm, be particularly Preference is given to component thicknesses between 3 and 37.5 cm. Lower component thicknesses lead to a low electromagnetic shielding attenuation, larger thicknesses are problematic from an economic point of view.

A at the same time sufficient mechanical strength, good thermal insulation properties and absorption capacity for electromagnetic Radiation is at a porosity between 40 and 90% by volume, preferably between 60 and 80% by volume, more preferably between Achieved 65 and 75% by volume. Here under the porosity the proportion of pore volume in the total volume of the material body is understood.

The Suspension used to make the components described above preferably contains between 30 and 99% by weight of the raw materials for the magnetizable powder particles, more preferably between 50 and 75 wt .-% of the powder particles described above. smaller Parts by weight of the powder lead to an insufficient Shield attenuation, larger shares to one insufficient thermal insulation of the components.

pictures

1 schematically shows the structure of a thermal insulation material according to the invention with its matrix ( 1 ) and the pores ( 2 ).

2 shows the shield attenuation perpendicular to a 1.5 cm thick component according to the invention as a function of frequency.

3 shows the honeycomb structure of a thermal insulation material with the shielding matrix ( 3 ) and the perpendicular to the image plane extending endless pores ( 4 ).

The The following examples illustrate the invention without them restrict.

embodiments

A mixture of 69% by weight of iron oxide, 16% by weight of manganese oxide and 15% by weight of zinc oxide is suspended in water. The solids content of the suspension is 65% by weight. The homogenized suspension is poured into a mold, e.g. B. of polytetrafluoroethylene, poured, which is geometrically similar to the component to be produced. The suspension is dried in the mold under hydrothermal conditions. The resulting porous shaped body is then sintered at 1050 ° C in a nitrogen atmosphere. The porosity of the sintered body is about 70% by volume. The screen attenuation measured on the sintered body is dependent on the frequency in the 2 to see. The thermal conductivity of the component is 0.3 W / (m · K).

ever according to the height of the sintering temperature or according to the duration of their Influence can be application-relevant properties, such as porosity, shielding attenuation and adjust the strength specifically. Leave the components obtained z. B. by sawing in their dimensions. Their on-site processing is identical to that of other heat-insulating Building materials.

A Special alignment of the pores can be achieved by extrusion become. The extrudable for this type of shaping necessary Mass requires the addition of temporary plastic components, which burn during subsequent sintering. A mixture of 71% by weight Iron oxide, 15 wt .-% manganese oxide and 14 wt .-% zinc oxide is at Calcined 900 ° C. The calcine will be added afterwards milled in a ball mill for 120 minutes. The crushed Ground stock in a kneader 12 wt .-% hydroxyl ethyl cellulose as plasticizer, 4.5% by weight of polyvinyl alcohol as binder and 2.5% by weight of polyethylene glycol as a lubricant. The Extrusion of the plasticized mass to components with per se known honeycomb structure, also referred to as "honeycomb structure" then leads to a porous shaped body. The sintering takes place at 1080 ° C under slow heating within 28 hours in nitrogen atmosphere and generated a coarsely porous ceramic structure. The porosity the sintered body is about 78% by volume. The thermal conductivity of the component is 0.23 W / (m · K) perpendicular to the extrusion direction.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• WO 02/13311 [0002]
• - DE 4439739 [0003]

Claims (11)

Material consisting of a porous Matrix, wherein the porous matrix at least partially made of magnetizable Material exists. Material according to claim 1, wherein the proportion of the magnetizable material on the porous matrix more than 80% by weight. Material according to one of the preceding claims, in which the porosity of the material is between 40 and 90 Volume%. Material according to one of the preceding claims, wherein the porous matrix is electrically conductive and / or semiconductive Contains ingredients. Material according to one of the preceding claims, wherein the porous matrix is partly or completely made of manganese-zinc ferrite. Material according to one of claims 1-4, wherein the porous matrix is partly or completely consists of magnesium-zinc ferrite. Material according to one of claims 1-4, wherein the porous matrix is partly or completely made of nickel-zinc ferrite. Material according to one of the preceding claims, wherein the porous matrix has a honeycomb structure. Material according to one of the preceding claims, the porous matrix containing stabilizers, which contribute to the mechanical strength. Use of the material according to one of Claims 1 to 9 for shielding a building or parts of a building or other demarcated Spaces against electromagnetic fields and / or for thermal insulation. Building material, consisting of a material according to a of claims 1-9.