EPP stands for expanded polypropylene. The foam beads simply contain air (96%) in addition to plastic. That’s why EPP is environmentally friendly and easy to recycle. The material comes in many great colors, from bright orange to a rich green.

In closed-cell foam, the walls between the individual cells are completely closed. The material (e.g. PE foams) cannot absorb liquids.

In open-cell foam, the cell walls are not closed and the material can absorb air and liquid.

Polyethylene foam (PE) is a closed-cell material with excellent properties, e.g. low density and thermal insulation. PE foams are divided into cross-linked (see cross-linked PE foam) and non-cross-linked PE foam.

Polyurethane (PUR) foam is a plastic formed by polyaddition of isocyanates with polyols. There are different types of foam: From soft, rather elastic foams to hard, rather brittle foams. Open-cell soft PUR foams are used, for example, for the production of filter inserts, household sponges, transport protection, upholstery in vehicle construction, seat cushions, mattresses, packaging. Closed-cell, hard PUR foams are used in the manufacture of packaging, suitcase inserts and for thermal insulation.

The density is calculated from the mass to its volume and, in the case of porous bodies, takes into account the enclosed air, i.e. how many kilograms a foam material weighs per cubic meter (kg/m³). The higher the volume weight at constant hardness, the better the usage properties, i.e. high elasticity with low material fatigue.

Compression hardness is the physical pressure in Pascal (Pa) acting on an area in square meters (m²), which is necessary to compress the foam by 40% according to DIN 53 577. The higher the compression hardness, the harder or firmer the foam.

Our production is certified according to ISO 9001:2008 and meets all related requirements. You can view our certificates here: https://www.wetropa.de/unternehmen/zertifikate/

In crosslinked PE materials, the polymer chains are interconnected at specific points and form a three-dimensional network. There are two types of crosslinking: a) chemical: crosslinking takes place through additives b) physical: crosslinking takes place through bombardment with electrons Crosslinked PE foam has a fine, regular and closed cell structure. The closed-cell structure offers excellent heat and cold insulation properties. In addition, crosslinked PE foam cannot absorb water. With different color variations, it can be designed in a particularly attractive way, e.g. with precisely fitting milled grooves, and has a smooth surface. Almost all crosslinked PE foams have very good thermoplastic properties. Cross-linked PE foam is also available in particularly bright colors and is therefore very suitable for presentation cases, for example.

Flexible foam refers to foams that have an open cell structure and are thus permeable to air.

Reduce CO2 emissions from manufacturer to reuse and increase recycling rate.

Original means a foam board with unfinished top or bottom surface. The surface is slightly wavy or grained, visually not particularly appealing but without qualitative disadvantages. Ideally suited for applications with low demands on appearance, with the advantage of lower vertical integration and cost savings.

By top coat we mean the finishing of a surface with a cross-linked PE foam. The surface is smooth, black and closed, waterproof and easy to clean without residues. This top layer is very often used for inserts that have a colored foam as a base. If customer parts are missing in such an insert, this is immediately recognizable due to the color difference.

For die-cut folding packaging, a special 3 mm foam layer is laminated onto the PE foam used. This layer is very stable and resistant to buckling. In the case of punched packaging, this layer is not punched through at special points, thus creating a “hinge” with which parts of the packaging can be folded out. These can be, for example, “feet” of the packaging or fixings.


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