Stauffer Chemical Co and Another v Safsan Marketing and Distribution Co (Pty) Ltd and Others

• Jurisdiction: South Africa
• Judge: Corbett JA, Viljoen JA, Hefer JA, Galgut AJA and Nicholas AJA
• Judgment Date: 18 August 1986
• Citation: 1987 (2) SA 331 (A)
• Court: Appellate Division

Corbett JA:

Before this Court are an appeal and a cross-appeal B against a decision of Nestadt J, sitting as Commissioner in the Court of the ' Commissioner of Patents, leave to appeal and cross-appeal having been granted ('in so far as it may be necessary') by Nestadt J and the parties having lodged with the Commissioner notice in writing in terms of s 76(4) of the Patents Act 57 of 1978 consenting to the appeal being heard by C this Court without any intermediate appeal.

The proceedings in the Court a quo took the form of an action instituted by first and second appellant's as plaintiffs (originally there was a third plaintiff but at some stage it withdrew from the action) against the respondents as D defendants, in which appellant's, alleging that respondents were infringing first appellant's South African patent No 72/2519, claimed an interdict and ancillary relief. In defence to the claim the respondents denied the alleged infringement and alleged upon various grounds that the patent was invalid. The alleged invalidity also formed the basis of a counterclaim by respondents for the revocation of the patent.

The Commissioner held that infringement had not been E established by appellant's and that respondents had failed to prove invalidity on any of the grounds relied upon by them. He accordingly dismissed both the claim and the counterclaim and made certain orders as to costs, to which I shall refer in more detail later. The appeal is directed against the dismissal of the claim and the cross-appeal against the dismissal of the F counterclaim and against certain aspects of the costs order.

The facts of the matter and the basic chemistry involved in the case are fully and accurately set forth in the careful judgment of Nestadt J which has been reported in Burrell's Patent Law Reports (see 1983 BP 209). Accordingly, I shall confine my G reference to the facts and the chemistry to those matters which are strictly pertinent to the reasoning of this judgment.

The Facts

First appellant, Stauffer Chemical Company, is a company incorporated in the United States of America, where it carries H on business on a very large scale as a manufacturer and distributor of, inter alia, agricultural chemicals. It is the registered proprietor of patent 72/2519, a convention patent entitled 'Herbicide Compositions', registered in South Africa on 4 May 1973, with 16 April 1971 as its priority date.

The invention described and defined in the specification of I patent 72/ 2519 consists of 'herbicidal compositions' comprising 'an active herbicidal compound' and an 'antidote' therefor. Before explaining these terms and elaborating upon the invention as described in the specification, it is necessary to take a brief look at the prior art.

The invention is, in popular parlance, a chemical weed-killer. It was evolved for use in respect of agricultural crop plants, J more especially

Corbett JA

A maize, or 'corn' as it is known in the United States of America. Weeds have always been the enemy of agricultural crops because they compete for the water and nutrients in the soil. One of the tasks of the agricultural farmer is, therefore, to eliminate weeds as far as possible from the land where his crops are growing. Earlier this was done in the United States B by tillage between the crop rows. The introduction in about 1945 of synthetic fertilisers, containing nitrogen, greatly increased the fertility of the soil. This improved the potential for crop growth, but at the same time it increased the weed menace. This problem stimulated the discovery and development of chemical herbicides designed to eradicate weeds.

C There were three methods evolved for the application of herbicides: (i) post-emergent, ie where the application is to the growing plants; (ii) pre-emergent, ie application to the soil surface after the planting of the seeds, but before the plants have emerged; and (iii) pre-plant incorporation, ie the herbicide is incorporated into the soil prior to planting.

One of the first chemical herbicides to be introduced D commercially (in about 1945) was a compound popularly known as '2,4 - D'. It was applied by the post-emergent method and was effective against broad-leaved weeds, but not against the grass species. The latter characteristic was both an advantage and a disadvantage. It was an advantage because it meant that 2,4 - E D did not harm grass-like crops, such as corn; it was a disadvantage in that the grass-like weeds, not being affected thereby and having less competition from weeds of the broad-leaved variety, multiplied rapidly. Another group of herbicides, similar in effect to 2,4 - D, were the S-triazines.

In about 1955 first appellant invented the thiolcarbamate F herbicides, which were very effective against grass-like weeds and controlled some broad-leaved varieties as well. The thiolcarbamates were only suitable for application by the pre-plant incorporation method. First appellant took out a South African patent, No 57/2419 (since expired), in respect of such herbicides. One of the embodiments of this invention was a compound generally known by the acronym 'EPTC'. This was very G effective against grass-like weeds and was a commercially successful product. But it had the disadvantage that it also tended to damage grass-like crops, such as corn, by causing malformation or stunted growth.

This problem led to the invention of the antidotes (or 'safeners'). The first of these, a compound which was H commercially exploited under the name 'Protecto', was applied as a coating to the seed of the crop before planting; but there were a number of problems (which need not be detailed) associated with this form of treatment. This led to the invention which is the subject-matter of the patent in suit. I turn now to the specification of that patent.

I In the section headed 'Background of the Invention' it is stated that among the many herbicidal compounds commercially available the thiolcarbamates, either alone or admixed with other herbicides such as the triazines, have reached a 'relatively high degree of commercial success'. Here reference is made, by way of example, to compounds described in certain J named United States patents. The section also adverts to the toxicity of these herbicides to weed pests and to the concomitant problem

Corbett JA

of injury to the crop plant. The specification then proceeds to A describe the invention in the following terms:

'It has been discovered thiolcarbamates alone or mixed with other compounds and/or the tolerance of the plants can be substantially increased to the active compounds of the above-noted US patents by adding to the soil an antidote B compound corresponding to the following formula:

wherein R can be selected from the group consisting of... C (and then follow the names of 50 or more radicals or groups of radicals)...; R1 and R2 can be the same or different and can be selected from the group consisting of... (and then follow 60 or more radicals or groups of radicals)... provided that when R1 is hydrogen R2 is other than hydrogen and halophenyl.'

The specification then describes how the compounds represented D by this formula can be synthesised and gives 42 examples of the antidote, with detailed instructions as to how each of these is to be prepared. Then follows a table of compounds (Table I) 'representative of those embodied by the present invention'. Table I lists 513 compounds (numbered from 1 to 513), all of which conform to the basic antidote formula quoted above. These compounds are referred to elsewhere in the E specification by the numbers assigned to them respectively in Table I.

Thereafter the specification describes how 'compositions of this invention', ie herbicide and antidote, were tested. The first test was a soil incorporation test. Trays ('flats') of soil were treated with varying solutions of herbicide and F antidote and seeds were planted in the soil. The trays were then kept under greenhouse conditions and the plants watered appropriately. The crop tolerance (indicated by the degree of malformation or stunting) at three weeks, four weeks and six weeks after planting was then rated. The results of this test are contained in Table II of the specification. Certain control tests were also done, ie the application of the herbicide without antidote and the results thereof are included in Table G II. The second test consisted of a corn seed treatment. The soil in trays was treated with herbicide. Seeds treated with antidotal protectant and untreated seeds were then planted in alternate rows. The trays were then kept under greenhouse conditions, with appropriate watering, and the resultant injury H (if any) to the plants at two weeks after planting and four weeks after planting was assessed. The results of this test, or series of tests, are contained in Table III of the specification.

The specification then continues to describe the invention and how it is to be performed and its preferred embodiments. Thereafter follow 44 claims. At this stage only claim 1 need be referred to. It conforms largely to the description of the I invention quoted above. I quote the relevant portion:

'1. A herbicidal composition comprising an active herbicidal compound and an antidote therefore corresponding to the formula:...'

(and then follow the formula quoted above and the same lists of J radicals from which R, R1 and R2 'can be selected'.)

Corbett JA

A As appears from the specification and the expert evidence, the novelty of the invention described in this specification resides in the composition of the antidote. This is defined by the organic chemical formula quoted above. The formula consists B of a nucleus or core, which falls under the amide functional group, represented thus -

and three radicals represented by the symbols R, R1 and R2. This core...