In T 57/82 (OJ 1982, 306) it was stressed that the subject-matter of an application relating to new chemical end products, processes for their preparation, and to new intermediates for those end products at all events had unity within the meaning of Art. 82 EPC 1973 if all these subject-matters were technically interconnected and integrated into a single overall concept by being oriented towards the end products. In this context, starting materials which were used in a process for preparing end products and which were themselves products of a disclosed, albeit unclaimed, production process were also considered to be intermediates. This principle was confirmed in T 110/82 (OJ 1983, 274) for low-molecular products. According to that board, an invention relating to new low-molecular end products and to several groups of new low-molecular intermediates invariably had unity if the groups of intermediates prepared and oriented towards the end-products were technically closely interconnected with the end products by the incorporation of an essential structural element into the end-products and if due account was taken of the regulatory function of Art. 82 EPC 1973 (prohibition of unjustified saving of fees, need for ready comprehensibility).
This was confirmed by T 35/87 (OJ 1988, 134) and T 470/91 (OJ 1993, 680). The intermediates in the latter case - unlike those in earlier ones - were not structurally related to each other. However, they provided both the essential structural elements present in the end products. The intermediates of the application were therefore only made available with a view to obtaining the end products and they were sufficiently closely technically interconnected with those end products. Thus, they were integrated into a single overall inventive concept by being oriented towards the end products. This was not prejudiced by the fact that the two sets of intermediates were not structurally related to each other since the orientation of the intermediates towards the end products permitted the individual technical problems addressed by the intermediates to be combined into a unitary overall problem to the solution of which both sets of purpose-made intermediates contributed.
In W 35/91 the board ruled that the requirements of unity of invention as set out in R. 13.1 and R. 13.2 PCT were met if the novel intermediates designed to give rise to the novel end products were technically sufficiently closely related by their contribution to an essential structural element of the end products.
In W 7/85 (OJ 1988, 211) the board stated that there was sufficient technical information to justify a prima facie finding of unity between a claim to a mixture and a claim to one essential component of that mixture or a narrowly defined version thereof. If a finding of unity was justified in cases of chemical intermediates and end products even when, as was often the case, only a part of the intermediate structure was actually incorporated, there was all the more reason to view the intact components and the corresponding compositions in a mixture as technically interconnected by incorporation. The former were not even destroyed when the admixture was prepared and fully retained their properties and functions in the product, unlike typical intermediates, which lost their identity in the process. Thus, both inventions could be considered to fall within the same general inventive concept. In such cases the requirement that the means for preparing the end product should be "specially designed for carrying out the process" appeared to be fulfilled since none of the means led or was related to an end product outside the scope of its definition. In view of this the character of the invention in the component was, prima facie, also dependent on the existence of an invention in the end product.