Do u honestly think CND would take a risk by NOT trade marking this all over the world??
If you click the links that others have posted, the word Shellac, on it's own along with other combinations HAS be trademarked by CND
If you are meaning the links I provided, they may have trademarked the word shellac, but it also means right down to the very detail of the font used, etc. It doesn't mean the word shellac no one else can use. It has to be exactly the way that CND lodged in their trademark.
Trademarks are very complicated because different countries around the world have different laws. The link I provided was American. It doesn't mean that it covers other countries. The designations TM and SM are often used for trademarks and service marks that are not registered, and serve as informal notices to the public that a word, logo, slogan, design, etc., is being used as a mark and reflects the owners intent to claim trademark rights in the mark. However, the right to use one of these symbols does not guarantee that the owner will succeed in a claim under the trademark laws.
If you read information on the Madrid Protocol, trademarks are not universal. The Madrid Protocol only covers 80 or so countries worldwide.
And to complicate matters further, trademarks are not patents. A patent is a government grant of an exclusive right to prevent others from practicing a new invention for a limited time. A patent is the only way in most countries to protect a new and useful invention and it must generally be applied for before any public disclosure of the invention. In some jurisdictions, such as the United States, a grace period is provided so that an application can be filed up to one year after disclosure.
CND C Color Shellac is currently patent pending. So that may change the whole ball game but at this stage it does not give CND exclusive right over producing Shellac. That's why other companies can do it.
At the end of the day, it would be too time consuming and cost far too much money for CND to try and stamp out other companies riding on their coat tails. They would have to take legal action against all other companies and then there would be no guarantee that they would win depending on the country the product is produced in. They are probably just happy to let their product speak for itself and the techs that use it to educate their clients what the difference between CND and other brand shellac is.