US 4,886,697 · Granted 1989-12-12
The Thermobonded Pad Patent Behind Disposable Car Seat Liners
This patent describes how to bind fibers and absorbent materials together using heat, then seal the edges to keep everything from falling apart or fraying. The edges stay soft and comfortable even after cutting, and the whole thing can be designed to tear apart along dotted lines when you want to replace it.
The plain-English version
What it protects
The claim covers a composite material made by mixing thermoplastic fibers with other fibers, heating them to bond together, and then densifying (compacting and hardening) the outer edges or margins of the eventual product. What's protected is the specific method of creating a soft-edged article by densifying only the periphery while leaving the interior softer, and the ability to add absorbent layers that stay locked in place through this thermobonding process. Also covered are versions with perforations or weakened tear lines built into densified sections.
Why it matters
This patent gave Weyerhaeuser a competitive advantage in manufacturing absorbent composite materials for infant car seat liners and similar products where you need durability at the edges but comfort and flexibility in the middle. The densified edge prevents fraying and unraveling during use and washing, while the soft interior maintains the article's intended feel. The ability to build in tear lines made the product user-friendly for consumers who need to replace liners regularly.
Real-world use
When you slide a disposable car seat liner into place and notice the edges don't fray or peel apart after repeated use, you're experiencing the result of this thermobonding and edge-densification process.
Original USPTO abstract
Materials have at least one layer comprising a mixture of thermoplastic and other fibers. This latter layer may be thermobonded together and then densified along at least a section of the eventual peripheral edge margin of an article to be formed from the material. Thermoplastic material-containing cover sheets may also be secured to the core and densified in this manner. The entire eventual peripheral edge margin of the article is typically densified. The material is cut within the densified region or slightly outside the densified region to provide a soft peripheral edge. Absorbent materials may be thermobonded within the layer and surrounded by a densified edge to fix them within the article. The composite materials are used in manufacturing infant car seat liners and other articles. In addition, sections of the material may be densified and provided with weakened areas, such as perforations, to enable users to selectively separate the articles along the perforations.
Patent details
- Publication number
- US 4,886,697
- Filing date
- 1988-04-29
- Grant date
- 1989-12-12
- Assignee
- Weyerhaeuser Company
- Inventor(s)
- PERDELWITZ, JR; LEE E., YOUNG; ROBERT H., IFF; RON H., HANKE; DAVID E., ALLISON; KATHLEEN S., RAHKONEN; RAIMO K., NEOGI; AMAR N.
- CPC class
- B32B7/12
Want to file your own patent?
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