What Is Polyurethane Integral Skin Foam?

Integral skin foam plastic, also known as molded integral skin foam plastic. This kind of foam plastic is different from general semi-rigid foam plastics. Usually, polyurethane semi-rigid foam uses plastics such as PVC or ABS as the surface material, with PU semi-rigid foam filled inside, forming a kind of “sandwich”-like layered material, which is used in industries such as automobiles and furniture as decorative material.

Integral skin foam plastic, on the other hand, does not use other plastics as the surface material. Instead, it relies on the foam components to simultaneously form the surface layer and the foam core during foaming and molding. That is, through special processes, PU components form foam plastic products with a solid surface skin in a single step.

Its outer skin is relatively thick, about a few tenths of a millimeter to 2.3 mm. Beneath this firm outer skin lies a porous structure. The skin density is 1000 to 1200 kg/m³, while the core density is several hundred kg/m³. The mechanical properties of the PU skin can fully compete with those of olefin plastic skins, and in some aspects even surpass them, such as puncture resistance. See the following table:

Comparison of Physical Properties Between PU Integral Skin Foam Skin Layer and Vinyl Plastic Skin Layer

At present, soft PU integral skin foam products are used in automobile steering wheels, armrests, headrests, bicycle seats, motorcycle seats, recliner armrests and headrests, door handles, deflectors, and bumpers, etc.

Most polyester-type PU integral skin products are used in the footwear industry to make various leather shoes, overshoes, mining shoes, riding boots, etc.

Rigid PU integral skin products are also called “structural foams.” They are used in the furniture industry to make doors, window frames, tables, chairs, computers, typewriters, pianos, and other strong and aesthetically pleasing frames, or used in sports equipment to make ski boards, surfboards, etc. The application prospects are very promising.

Comparison of Puncture Resistance Between PU Integral Skin and Vinyl Plastic Skin

①Puncture test uses a round special needle to pierce the skin.

②Integral skin foam size: 17.78 cm × 17.78 cm × 5.08 cm.

Integral skin foam has a high-strength outer skin layer, and the physical and mechanical properties of its products greatly exceed those of ordinary foams with the same density. Therefore, under the premise of requiring the same properties, only a lower-density integral skin product is needed, thereby saving material and reducing cost.

Comparison of Properties Between PU Integral Skin Molded Foam and Common PU Foam

For integral skin foam, based on product density, it can be divided into light-type and heavy-type integral skin products. Based on raw materials, there are polyether type and polyester type. Based on product hardness, there are soft and rigid integral skin foam products.

Light and heavy integral skin foams have significantly different density distributions. Light integral skin foam has a large density difference between outer and core layers, while heavy integral skin foam has a smaller difference.

Soft PU integral skin is mainly used in automobile steering wheels, armrests, headrests, bicycle seats, motorcycle seats, recliner armrests and headrests, door handles, deflectors, and bumpers, etc.

Rigid integral skin foam, also known as "structural foam," is used in furniture for doors, window frames, tables, chairs, computers, typewriters, and pianos, etc., or used in sports equipment to make ski boards, surfboards, etc.