Admissibility of Late-Filed Evidence and Key Procedural Considerations

French version available here

Introduction

In decision T1856/22, issued on September 20, 2024, the Board of Appeal addressed key procedural and substantive issues in the context of a European patent concerning aqueous polyurethane dispersions (EP 3253812). This case revolved around the admissibility of late-filed evidence, the inventive step of the claimed subject matter, and alleged violations of procedural rights, including the right to be heard.

The decision underscores the importance of adhering to procedural rules under the Rules of Procedure of the Boards of Appeal (RPBA) and highlights the challenges of presenting additional evidence during appeal proceedings.

Summary of the Invention

The patent in question relates to aqueous polyurethane dispersions, widely used in coatings, adhesives, and sealants. The claimed invention focuses on dispersions prepared using a combination of specific chemical components, including:

1. Isocyanate-terminated prepolymers,
2. Specific water-dispersible enhancing compounds containing hydrophilic groups, and
3. A tailored range of molecular weights for polyols.

Key inventive features aim to improve the environmental profile and performance characteristics of the dispersions, particularly in terms of reduced toxicity and superior stability.

Summary of the Decision

Legal Issues

The appeal originated from a decision by the Opposition Division rejecting an opposition filed by AdvanSix Resins & Chemicals LLC against European Patent No. 3253812. The Board analyzed:

1. The admissibility of late-filed experimental evidence provided by the patentee (Taminco).
2. Whether the granted claims meet the requirements of inventive step (Article 56 EPC).

Arguments on Late-Filed Evidence

Patentee’s Position:

• Additional experiments (filed in June 2023) were submitted to address arguments from the appellant's statement of grounds.
• The patentee argued that the experiments were delayed due to logistical challenges stemming from the COVID-19 pandemic and were necessary for clarifying disputed technical effects.

Opponent’s Position:

• The appellant contended that the experiments could and should have been submitted earlier during opposition proceedings.
• Late submission violated procedural economy and fairness principles.

Board’s Findings:

• The Board rejected the late evidence under Article 12(6) and 13(1) RPBA 2020, stating that the evidence should have been submitted earlier.
• Procedural history indicated no attempts by the patentee to address these issues during opposition proceedings, undermining the justification for late filing.

Inventive Step Assessment

Opponent's Argument:

• The claimed invention lacked an inventive step over D1 (closest prior art) in combination with D4.
• The use of N-butylpyrrolidone (NBP) as a solvent, while reducing toxicity, was deemed obvious in light of D4's teaching.

Patentee’s Defense:

• Argued that the claimed polyurethane dispersions exhibited unexpected technical effects, including enhanced dispersion stability and reduced toxicity.
• Highlighted the environmental benefits of using specific hydrophilic compounds and solvent systems.

Board’s Conclusion:

• The Board agreed with the appellant, concluding that the claimed subject matter lacked an inventive step.
• The combination of prior art provided sufficient motivation to substitute the solvent system with NBP, rendering the claimed technical effects foreseeable.

Lessons Learned

Timely Submission of Evidence

• Article 12(6) RPBA explicitly discourages late submissions unless justified by new circumstances. Applicants and patentees should anticipate potential objections and prepare supporting evidence during opposition proceedings.

Importance of Procedural Compliance

• Late filings risk exclusion, even if the evidence addresses critical aspects of the case. Procedural economy and fairness are paramount in appeal proceedings.

Inventive Step and Technical Effects

• Alleged unexpected effects must be credibly linked to distinguishing features of the invention and supported by comparative tests against the closest prior art.

Link to the case : HERE 

Contact

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Legal Disclaimer

The information provided in this blog post is for generalinformational purposes only and does not constitute legal advice. The summary and analysis of the EPO case are based on publicly available information and are intended to offer insights into the decision and its implications. This content should not be used as a substitute for professional legal advice tailored to your specific circumstances. For advice related to any specific legal matters, you should consult a qualified attorney.