China Prosecution History Estoppel: SPC Clarifies Limits in New Patent Case
In a patent infringement case, the Supreme People’s Court (SPC) of China has ruled in favour of the patent holder, the German company Rose Plastic AG. The SPC clarified that statements distinguishing the invention from prior art should not automatically be interpreted as a comprehensive disclaimer of specific material variants. Consequently, the judgment of the court of first instance was overturned, patent infringement was established, and Rose Plastic was awarded damages. Experts from Shanghai K-insight Law Firm present the ruling.
The key points of the case
- The patent involved: An invention titled “Polygonal Sliding Packaging” (Patent No. ZL201310204227.3), owned by German company Rose Plastic AG.
- Procedural history: Rose Plastic sued two defendants for patent infringement. The first-instance court (Guangzhou Intellectual Property Court) dismissed all claims, applying the prosecution history estoppel. It held that the patentee, during the substantive examination, had distinguished its invention by stating its material was “rigid and bend-resistant,” thereby disclaiming the elastic plastic material used in the disputed product. Rose Plastic appealed to the SPC.
- Technical dispute: The core issue was the interpretation of the claim limitation that “the two hollow bodies are made of a rigid and bend-resistant material.” The patent’s inventive concept lies in a structural design that enables opening/closing without relying on wall deformation. The disputed product is made of plastic.
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Annie Li, Lawyer, Shanghai K-insight Law Firm – A Member of ECOVIS International, Shanghai, China
The interpretation and justification of the SPC
- Proper construction of “rigid and bend-resistant material”: The SPC ruled that the term must be interpreted in the context of the invention’s purpose. The patent’s specification aimed to overcome the problem of prior art, which required wall deformation. The claimed “rigid and bend-resistant” material refers to materials that do not undergo significant deformation under normal use, not to materials that are absolutely non-deformable. Relatively rigid plastics are not excluded.
- Rejection of overly broad application of prosecution history estoppel: The SPC clarified that a patentee’s arguments made during prosecution to distinguish prior art do not automatically constitute a clear and unambiguous disclaimer of an entire category of technical solutions. In this case, Rose Plastic’s emphasis on “rigid” material was to highlight the structural difference from prior art that relied on elastic deformation, not to expressly abandon all plastic materials capable of any deformation. Without such clear abandonment, the prosecution history estoppel principle should not be invoked to unduly narrow the scope of protection.
- Infringement Found: Applying the correct claim construction, the SPC found that the disputed product’s unlocking mechanism did not rely on wall deformation. Therefore, the plastic material used fell within the scope of “rigid and bend-resistant material” as properly construed.
