Patent classes and keywords

In order to get data about patent activities of chemical firms we used two different methodologies. 

End-of-pipe technologies are recorded by the German Patent Office in the class C02F of the International Patent Classification (IPC) Treatment of water, waste water, sewage or sludge. This class is further divided into six subclasses  

C02F - 1/00 treatment of water, waste water, or sewage (3/00 to 9/00 take precedence) 

In order to select the individual firms for the empirical investigation we classified the population of chemical firms into four groups according to the number of employees (see table 2, first column). 

Firm size Total of West German Selected firms 

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It is often appropriate to look at all the patents assigned to a specific class/subclass. However, it is important to use keywords to search the titles, abtracts, and claims, and sometimes even the full text of patents within a broader range of patent classes in order to capture all patents of interest. 

Data about patent applications in the field of production-integrated technologies that reduce waste water at source could not be obtained because the main claim of the patent application does not indicate that emissions are avoided at source. Hence, the use of keywords was not possible. Figure 2 takes up figure 1 and depicts the classes of patents and keywords we used to obtain data on patent activities at the firm level. 

Figure 2. Classes of patents and keywords to measure R D that reduces water pollution.

We measured corporate inventive activities with by means of patent applications. In order to get data about patent applications in the field of water benign process technologies we selected the patent class C02F and used keywords. 

The U.S. Patent and Trademark Office is located in Crystal City, VA, and more importantly on the Internet as USPTO.com. It offers an extensive database, which can be accessed easily. One can search by inventors, assignees, titles, keywords, patent classes, etc. It is updated every Tuesday. 

Lexis-Nexis Academic Universe (http //web.lexis-nexis. com/universe/) is a useful site for legal and government information on the internet. A separate section under Legal Research leads to Patent Research . Keyword searching of the Patents section is available, with an option to narrow fields by type of patent, etc. The Class section is searchable by patent number. The database covers patents back to 1971. Results are returned in HTML format, and pictures are (currently) not available. 

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