3M Co. filed a trademark infringement case against a Chinese company it said wrongfully claims to be using auto paint technology it developed for collision repairs.

The case, filed Friday in federal court in the U.S. Western District of Wisconsin, is against Thunder Finish Co. 3M said Thunder Finish is also wrongfully using one of its trademarks in marketing materials.

3M has filed several lawsuits over this technology, mostly against Chinese manufacturers. The Maplewood-based conglomerate is trying to protect a paint preparation system, or PPS, it created and trademarked that allows auto repair technicians to more efficiently mix and spray coatings.

The company is seeking an injunction against Thunder Finish from using or marketing the technology. In April, 3M sued California company K2 Concepts and China's Phoenix Auto Refinishing over the same use of the cup-and-liner technology related to the coating sprayer.

3M said in the lawsuit that it has made "significant investment" not only in the research and development of the PPS technology but also in industry education, sending employees to repair shops across the country to show them how to use the sprayers.

It also has provided the shops with stainless steel adapters to allow the technicians to connect the PPS system to many spray gun models.

The lawsuit was filed in Wisconsin because Thunder Finish was marketing the products to businesses in that state, court papers said.

3M declined to comment on the lawsuit. Thunder Finish representatives could not be reached for comment.

Catherine Roberts • 612-673-4292