Basf Aktiengesellschaft

Hermann Tatzel

Isidoor De Grave

Ludwig Zuern

Udo Haardt

Wolfram Koegel

Klaus Hahn

Hans D Zettler

Arndt Christian Caesar

Gilbert Beck

Erhard Seiler

Walter Heckmann

Frank Braun

Juergen Kerth

Wolfgang Loth

Guiscard Gl&uuml;ck

Rainer Alexander Werner

Harald Schwager

Karl-Heinz Wassmer

Rolf Henn

Reinhold Weber

Onno Graalmann

Hans-Dieter Schwaben

Manfred Weilbacher

Friedrich Domas

Joachim Fischer

Wolfgang Schneider

Uwe Blumenstein

Klaus Hinselmann

Gerhard Dembek

Fritz E Krueckau

Christof M&ouml;ck

Sandwich panel

The invention relates to expanded polypropylene beads having a density of from 5 to 200 g/l and a bead diameter of from 1 to 10 mm which comprise from 0.002 to 20% by weight of graphite particles.

Expanded polypropylene particles

The invention relates to sound-absorbent foam moldings which have a sound-absorption level according to DIN 52215 of from 30 to 95% in the frequency range from 0.5 to 4 kHz. The foam is an incompletely fused molded polyolefin or polystyrene foam with from 10 to 40% interstitial volume.

Sound-absorbent foam moldings

The invention relates to expandable styrene polymers for elastic polystyrene foams, comprising

Expandable styrene polymers

Moldings made from polyolefin particle foams having a mean density of from 0.015 to 0.100 g/cm.sup.3 and having at least two different regions whose densities differ by from 0.005 to 0.030 g/cm.sup.3 have a transition zone between the different density regions having a thickness of not more than 25 mm. A method of forming the moldings, using removable mold dividing walls, is described.

Method of forming foam moldings having varied density regions

A shock-absorbing propylene polymer composite molding contains

Shock-absorbing propylene polymer composite moldings

Moldings made from polyolefin particle foams having a mean density of from 0.015 to 0.100 g/cm.sup.3 and having at least two different regions whose densities differ by from 0.005 to 0.030 g/cm.sup.3 have a transition zone between the different density regions having a thickness of not more than 25 mm.

Foam moldings having various density regions, the production thereof,

Novel foams having a density of from 0.01 to 0.1 g/cm.sup.3, based on a copolymer comprising ethylene, propylene and a C.sub.4 - to C.sub.8 -.alpha.-olefin, and having a torsion modulus of from 100 to 800 N/mm.sup.2 have high tensile, compressive and flexural strengths and at the same time high elongation at break.

Foams based on an olefin copolymer

Foam particles of propylene polymers which have shrunk from 40 to 95% of their original volume and have a bulk density of from 10 to 30 g/1 can be expanded if they are treated with air or nitrogen under superatmospheric pressure, subsequently decompressed. If desired post-foamed by heating and, after aging, re-treated with air or nitrogen under superatmospheric pressure, subsequently decompressed and aged under atmospheric pressure until the pressure in the cells has dissipated.

Expansion of shrunk foam particles of propylene polymers

Foams having high compressive strength are obtained by extrusion of a mixture of a styrene polymer and from 3 to 9% by weight of a blowing agent consisting of from 80 to 100% by weight of CO.sub.2 and from 0 to 20% by weight of one or more halohydrocarbons or hydrocarbons which are gaseous at room temperature, the mixture being extruded into a zone under from 0.1 to 2 bar gage pressure and the foam being allowed to stabilize under this pressure.

Preparation of foams having a high compressive strength

Polyolefin foams which have a density of from 30 to 300 g/l, do not exhibit after-shrinkage and possess taut cells are prepared by letting down a polyolefin/blowing agent gel, the latter first being let down to 0.1-10 bar gage pressure and the foam being kept at this pressure until it has cooled to at least 20.degree. C. below the expansion temperature.

Preparation of polyolefin foams

Shaped articles are produced by heating and compressing particles of foamed olefin polymer containing crosslinked portions in molds, the pressure being reduced during compression in the mold.

Manufacture of shaped articles of foamed olefin polymers

Foam moldings of olefin polymers are prepared by heating, and pressing together, foamed particles of an olefin polymer, containing crosslinked constituents, in molds, a temperature gradient of from 0.5.degree. to 25.degree. C per cm of loose mass of particles being established in the mold, which has a gas-permeable wall on the lower-temperature side.

Growing community of inventors

Weinheim, Germany

Hermann Tatzel