There is no such thing as an international patent. If you foresee doing business in the us you must file with uspto. A patent filed in China only gives you a priority date that nobody else can file an application anywhere else. It does not give you an enforceable right outside China. Similarly, an application filed under PCT only preserves you the right in the signatory countries. PCT itself is not a patent and you must enter national or regional stage in each of countries that you will be doing business within a certain period of time to be protected.
A us patent filing is long. A typical filing takes about 3 years today. However, the cost is minimal, especially if you can claim small business status or other exemptions.
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