Renia Primers: Solving Difficult Shoe Repairs with Contact Adhesives

When it comes to modifying or repairing shoes, especially those made from tricky materials like 'plastic soles' often found in cheaper footwear, it can feel like nothing will stick. This is a common issue for professionals such as podiatrists and orthotists when patients bring in either a newly purchased pair of shoes or their favourite, well-worn pair, asking for orthopaedic adjustments.

You might be tempted to turn to a classic contact adhesive, like Neoprene cement, or even resort to Superglue. However, while Superglue may seem like a quick fix, it often makes materials brittle and prone to cracking. Plus, it’s not cost-effective - those small bottles add up over time.

So, is there a better solution when contact adhesives don’t seem to do the trick? The answer lies in understanding the materials you’re dealing with and preparing them properly using the right primers, like Renia Primers, to create a strong, lasting bond.

The Challenge: Polyurethane (PUR) and Thermoplastic Rubber (TR) Soles

Two common materials where traditional contact adhesives, such as Neoprene cement, struggle are Polyurethane (PUR) and Thermoplastic Rubber (TR). These materials are commonly found in modern footwear, especially mass-produced or budget-friendly options. However, they can be notoriously difficult to bond using standard methods.

Polyurethane (PUR) Soles: Combating Ageing and Adhesion Problems

Polyurethane, or PUR, is frequently used in shoe soles, which often have a smooth, tough exterior and a foamy, porous interior. Unfortunately, foamed PUR does not age well—it’s particularly vulnerable to sunlight and moisture, which can cause it to degrade over time. Even when it’s fresh, many traditional contact adhesives, including Neoprene-based ones, simply don’t bond well to PUR.

This is where Renia adhesives come into play. These contact adhesives provide excellent bonding to PUR, whether the material is new or showing signs of wear. If the PUR sole is ageing and starting to break down, Renia - Primer for PUR offers a great solution. This specialised primer reinforces the aged PUR, creating a stronger foundation for the contact adhesive to adhere to. While it won’t help if the sole is already falling apart, it can make a huge difference for older PUR soles that are still intact.

Renia - Primer for PUR: A small but powerful tool for improving adhesion on ageing PUR soles.

Thermoplastic Rubber (TR) Soles: Proper Surface Preparation is Key

Thermoplastic Rubber (TR) poses its own challenges. In most workshops, you would typically sand a surface before applying a contact adhesive, but with TR, this approach simply doesn’t work. Sanding doesn’t adequately prepare the surface for bonding, making it difficult to achieve a lasting repair.

In large-scale shoe manufacturing, TR is typically prepared through halogenating—a process where the surface is treated with chlorine rather than sanded. This is why TR soles are so difficult to bond using standard methods. To overcome this issue, Renia offers Renia - Rehagol (Primer for TR). This halogenating agent acts like a “chemical sanding,” preparing the TR surface for a much stronger bond with contact adhesives.

For best results, Renia - Rehagol should be used in conjunction with Renia - Colle de Cologne or Renia - Syntic Total adhesives. These contact adhesives are specially formulated to work with Rehagol, ensuring a chemical bond that is much stronger than what could be achieved with traditional methods. By using this combination, you can recreate the factory-level halogenating process in your own workshop, delivering professional-quality results.

Renia - Rehagol (Primer for TR): A professional solution for bonding TR soles.

Contact Adhesives and Primers: The Right Combination for Success

When it comes to tricky shoe modifications involving difficult materials like PUR and TR, using the right contact adhesive is only half the battle. Proper preparation of the surface is essential for ensuring a secure, long-lasting bond. Renia Primers are specifically designed to address the unique challenges presented by these materials, giving you the tools you need to achieve professional results.

By using Renia - Primer for PUR to reinforce ageing PUR soles and Renia - Rehagol (Primer for TR) to properly treat TR soles, you can significantly improve the success of your repairs. These primers, when used with contact adhesives like Renia - Colle de Cologne or Syntic Total, create a bond that is both chemical and mechanical, ensuring durability and strength.

Technical and Safety Information

For detailed technical specifications and Material Safety Data Sheets (MSDS), please visit our website. All documents are regularly updated to comply with the latest government regulations and industry standards, ensuring that you always have access to the most current information.

Conclusion: Tackling Difficult Shoe Repairs with Confidence

When you’re faced with difficult shoe repairs involving materials like Polyurethane (PUR) and Thermoplastic Rubber (TR), don’t settle for subpar solutions like Superglue or ineffective contact adhesives. By understanding the materials and using Renia Primers in combination with high-quality Renia contact adhesives, you can confidently tackle even the toughest repairs.

Whether you’re reinforcing an ageing PUR sole or preparing a TR sole for bonding, Renia provides the specialised products you need to achieve lasting results. Keep your patients happy and their shoes in great condition by relying on Renia’s trusted range of primers and contact adhesives—ensuring that your repairs stand the test of time.

Original article kindly supplied by Renia GMBH.

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