Polyurethane Systems

We offer a comprehensive range of polyurethane systems, with a number of different grades of raw material formulations available, each providing significant benefits such as strength, density, flexibility, UV resistance and flammability resistance.

Speed and precision

Here we have our polyurethane soft foam moulding cell, capable of producing 10,000 armrest foam pads per week for a high-volume automotive customer.

With our automatic carousel and KUKA robot for automatic precision pouring we are able to produce 1/2 million armrests a year at our Linecross Cannock site.

What are Polyurethane Systems used for?

Our extensive polyurethane range of systems include:

Flexible soft foam systems

Suitable for e.g. armrests, waist-rails and console lids.

Soft PU foam, also known as flexible polyurethane foam, is a type of polyurethane foam that is engineered to be soft, cushiony, and highly comfortable. It is widely used in a variety of applications where comfort and support are essential. Soft PU foam is produced through a chemical reaction between polyols and isocyanates, which generates a foam with an open-cell structure.

The cell structure allows air to flow freely within the foam, giving it its characteristic softness and resilience. The level of softness can be adjusted during the manufacturing process by varying the formulation of the foam. This allows for a range of firmness options, from very soft and plush to slightly firmer, depending on the intended use.

Soft Foam Over Moulded Armrest 900 900 85 s c1

Integral skin (self-skinning) systems foam

Suitable for use in grab handles and energy absorbent restraints.

Integral PU foam, also known as integral skin polyurethane foam or simply integral foam, is a type of polyurethane foam that possesses a unique structure. It is called "integral" because the outer skin and the core are formed together in a single manufacturing process.

The integral PU foam is created using a chemical reaction that involves two main components: a polyol blend and an isocyanate. When these components are mixed, they undergo a foaming reaction. During this process, the outer skin of the foam is formed due to the rapid reaction of the chemicals, while the core remains in a more liquid state.

The outer skin of integral PU foam has a higher density and a more compact structure compared to the inner core, which remains softer and less dense. This results in a material with a tough, durable, and abrasion-resistant outer layer, while the inner core remains lightweight, flexible, and comfortable.

At Linecross we use this process to manufacture a variety of products for our clients such as armrests, handles, and other applications where a combination of durability and comfort is required. It is well-suited for items that need to withstand wear and tear while still providing a pleasant tactile experience.

Structural Reaction Injection Moulding (SRIM)

SRIM combines the benefits of traditional injection moulding and composite materials, resulting in parts that exhibit enhanced strength, stiffness, and impact resistance.

The SRIM process involves injecting liquid reactive components, typically a mixture of resin and fibre reinforcement, into a mould. The mould is usually heated and pressurised to facilitate the chemical reaction and curing of the resin. The reaction creates a solid composite part with high strength-to-weight ratio, excellent dimensional accuracy, and complex shapes (typically 20-30% lighter than injection mouldings)

Examples include front-end modules, boot floors, bulkheads, instrument panels, door panels, and reinforcement for engine covers.

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What are the advantages of SRIM

The Structural Reaction Injection Moulding (SRIM) process offers several advantages to produce composite structures:

Lightweight & strong

SRIM produces composite parts that have excellent strength-to-weight ratios. The combination of resin and fibre reinforcement results in lightweight components that still possess high structural integrity.

Design flexibility

SRIM allows for the creation of complex shapes and intricate designs. The liquid nature of the injected material enables it to flow and fill detailed moulds, providing greater design freedom compared to traditional manufacturing methods.

High-strength composites

The use of fibre reinforcements, such as fiberglass or carbon fibre, adds significant strength and stiffness to the finished parts. This makes SRIM components suitable for load-bearing applications and structural elements.

Fast production cycle

The reaction and curing process in SRIM is relatively quick, resulting in shorter production cycles compared to other composite manufacturing methods like hand lay-up.

Integrated parts

SRIM enables the incorporation of multiple functions into a single part. This reduces the need for assembly and can simplify the overall product design, leading to cost savings and improved efficiency.

Excellent dimensional accuracy

The use of moulds and the controlled injection process in SRIM contribute to high dimensional precision and consistency in the produced parts.


While SRIM may have higher initial tooling costs compared to other processes, it becomes cost-effective for medium to high production volumes due to its efficient cycle times and the ability to produce multiple parts simultaneously.

Enhanced part surface finish

Components can be in-moulded with a surface foil (UEV or TPU / TPO) for aesthetic finishes.

Overall, SRIM combines the advantages of composite materials with the efficiency of the reaction injection moulding process, making it a preferred choice for manufacturing structurally strong yet lightweight components used in various industries, including automotive, aerospace, and construction.

Get in touch

At Linecross we provide a complete ‘concept to production’ service from customised product development to assembly and sequenced supply. Find out more about how our range of processes can support your business.

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