Kourtney Kardashian, Kendall Jenner Khloe Kardashian & Kylie Jenner. Picture: Instagram

Documents filed to the United States Patent and Trademark Office show that the Kardashians sisters - Kim, Kourtney and Khloe - are trying to block Blac Chyna from trademarking the name 'Angela Renée Kardashian'.

The Kardashians are trying to block Blac Chyna from trademarking Angela Renée Kardashian.

The legal representatives for Kim, Khloe and Kourtney Kardashian have filed documents to the United States Patent and Trademark Office to block the 28-year-old model's company Lashed LLC from trademarking her name with Kardashian tagged alongside it.

The lawyers claim the Kardashians will "suffer damage, including irreparable injury, to their reputation and goodwill" if Chyna's request is granted. In the documents, the Kardashians' attorneys claim the sisters "own and control the rights in the 'Kardashian' brand and related trademarks and services marks."

They continued: "[They have] spent, and continue to invest, a substantial amount of time, resources and money in protecting, advertising and promoting the 'Kardashian' marks [and] the public has come to associate goods and services bearing the 'Kardashian' marks [with them].

A photo posted by Blac Chyna (@blacchyna) on

She is deliberately seeking to profit from the goodwill and popularity [of the Kardashians and it is] likely to cause confusion, or to cause mistake, or to deceive consumers." However, a source insists there is no bad blood between the Kardashian sisters and Chyna, who is engaged to their brother Rob.

A source told E! News: "Their trademark attorneys automatically oppose anyone trying to trademark 'Kardashian'. I doubt the girls were even aware. Everyone loves each other. It's just business."

Meanwhile, Rob recently took to social media to gush about his baby girl Dream. Sharing a picture of the little girl, he wrote: "Sleep baby,,,, best thing that has ever happened to me in my life (sic)" And Rob and Chyna are reportedly busy trying to find a camera-friendly venue for their wedding in the hope they can secure a deal for it to be filmed for television.