Drafting an Israeli patent application for a chemical composition or advanced material requires careful attention to Israeli patentability and disclosure rules, not merely the translation of claims prepared for the USPTO or EPO. Drori Stav IP assists companies, investors and foreign patent counsel with chemical and materials patent applications before the Israel Patent Office, including claims concerning polymers, coatings, compositions and manufacturing processes.
Chemical and materials patent drafting presents a particular challenge: the inventive contribution does not always involve creating an entirely new substance. It may result from combining known materials, selecting a particular concentration range, changing a material’s internal structure or developing a manufacturing process that gives the resulting material new properties.
The drafting task is to define the technologically valuable contribution in the claims while ensuring adequate support in the specification and experimental results. An inappropriate limitation concerning a component, a numerical range or a physical property may unnecessarily narrow the protection or create difficulties when novelty and inventive step are examined.
Israeli Patent Law: Requirements for Chemical and Materials Claims
Sections 3–5 of the Israeli Patents Law, 5727-1967, govern patent eligibility, novelty and inventive step. Section 12(a) requires a specification describing how the invention can be carried out by a person skilled in the art; Section 13(a) requires each claim to be reasonably supported by the description. Regulation 20(a)(3) of the Patents Regulations requires the claims to define the invention clearly and concisely. These rules apply to chemical compositions, material structures and process inventions filed in Israel.
The Israel Patent Office’s official filing guidance calls for the specification to explain the technical field, relevant prior art, differences from known technology, methods of performing the invention and experimental results where available. Its published patent examination instructions address claims, disclosure, unity of invention, novelty and inventive step, including the examination of chemical alternatives and material properties.
For an Israeli application, the drafting question is therefore not simply how broadly a family of chemicals can be described. It is whether the claimed compositions or processes are new and inventive under Israeli law, clearly defined, and sufficiently supported by the material disclosed at filing. This is particularly important when the Israeli application relies on a PCT specification or an earlier US or European filing that contains broader functional language than the experimental evidence supports.
Drafting Claims for Chemical Compositions: Which Components Are Essential?
Consider a company developing an industrial coating with improved corrosion resistance. The coating is based on a polymer resin, a crosslinking agent and an additive that improves adhesion to metal.
If the inventive contribution arises from an interaction between the resin and the additive, the drafter must consider whether the claims should be limited to the particular additive tested in the experiments or whether a broader family of compounds with shared characteristics can achieve the same effect.
The choice directly affects the scope of protection. A claim limited to a particular commercial additive may allow a competitor to use an alternative compound. Conversely, a claim covering every substance that improves adhesion, without supported chemical or functional characteristics, may be broader than the invention warrants.
One way to express chemical alternatives is through Markush claims, which describe a family of compounds by reference to a common chemical structure and variable substituent groups.
The Israeli examination instructions address Markush practice expressly in Annex D, Section 4.2, under the statutory requirement for unity of invention in Section 8. The alternatives must share the same activity, technical effect or use, together with either a significant common structural element relevant to that effect or membership in a recognized class of compounds for which comparable behavior may reasonably be expected. The examination also considers whether cited prior art destroys the technical concept common to the alternatives.
This Israeli guidance should be the starting point for structuring Markush claims in a patent application examined in Israel. The EPO Guidelines concerning Markush groupings provide a useful comparison for corresponding European claims, but the Israeli examiner applies the Israeli Patents Law and the Israel Patent Office’s examination instructions.
Concentration Ranges and Component Ratios: When Is a Narrow Selection Inventive?
In chemical manufacturing, product characteristics may be particularly sensitive to the quantity of an individual ingredient.
Suppose development of an industrial cleaning composition shows that a specific concentration of surfactant offers a useful combination of cleaning efficiency and solution stability. An overly broad claim may cover known formulations or concentrations that do not provide the stated technical benefit.
In an Israeli patent application, a selected concentration range must be examined under the novelty and inventive-step tests in Sections 4 and 5, alongside the supporting disclosure required by Sections 12 and 13. The drafter should identify the prior-art examples, the boundaries of the selected range and the technical effect demonstrated across the range. A comparative illustration appears in the 2026 EPO Guidelines on selection inventions: a detergent composition with 3% to 6% by weight of surfactant, compared with an earlier 1% to 30% range and an example at 25%. The example illustrates a technical issue, not a substitute for analysis under Israeli law.
In the circumstances described by the Guidelines, the narrower range may satisfy novelty because it is relatively narrow and sufficiently removed from the earlier example. By contrast, an earlier specific example at 4.5% could destroy the novelty of the claimed range.
Novelty alone is not sufficient. The selected range must also satisfy the requirement of inventive step. A particular concentration may be considered obvious if it is the predictable result of routine optimization. Where the claimed range produces a technical advantage, the specification should ideally include results demonstrating the significance of the selection, especially comparisons between concentrations within and outside the range.
For alloys, polymer blends and composite materials, the contribution may depend on the relationship among several components rather than a single concentration. The claims should reflect the relevant technical combination instead of treating each numerical range in isolation.
Patents for Polymers and Advanced Materials: Beyond the Chemical Formula
Two products with similar chemical compositions may behave very differently. The properties of polymers, for example, may depend on molecular weight, molecular weight distribution, crystallinity, pore structure and processing conditions.
Consider a company developing a polymer membrane for industrial filtration. The difference between the new membrane and existing products may arise not from the starting material but from its pore geometry, mechanical strength or a particular balance between permeability and separation selectivity.
The drafter must assess whether to define the invention through structural characteristics, such as pore size or pore density, measurable properties, such as permeability or burst pressure, or a combination of the two.
Parameter-based claims require particular precision. Where a claim specifies tensile strength, the method of measuring that strength may need to be identified. Results can vary with sample geometry, test conditions and the rate at which a load is applied.
The EPO Guidelines on claims defined by parameters address clarity and reliable determination of such parameters. Where the relevant measurement method is not self-evident to a person skilled in the art, the specification should identify a method enabling the boundaries of the claimed subject matter to be determined.
Effective patent drafting in materials science therefore requires an understanding not only of the substance itself, but also of the characterization techniques used to distinguish it from known materials.
Protecting Chemical Manufacturing Processes: The Gore Patent Example
Sometimes the inventive advance lies not in the chemical composition but in a manufacturing process that changes the material’s internal structure.
An illustrative example is US Patent No. 3,953,566, assigned to W. L. Gore & Associates and granted in 1976, concerning the production of porous articles from tetrafluoroethylene polymers, particularly PTFE.
Claim 1 does not merely claim the desired result of obtaining a porous material. It sets out a process involving stretching an unsintered PTFE article after paste extrusion and removal of the lubricant, at a rate exceeding approximately 10% per second and at a temperature between approximately 35°C and the crystalline melting point of the polymer.
The dependent claims add more specific features. Claim 13 concerns porosity of approximately 40% to 97%, while Claim 23 adds heating after stretching to a temperature above the polymer’s crystalline melting point.
The example demonstrates how a process may be protected by specifying the conditions responsible for obtaining the desired structure, rather than merely describing the intended outcome.
A distinction must also be drawn between a claim to a manufacturing process and a product-by-process claim, which defines a product by how it is made. Under the EPO Guidelines on product-by-process claims, defining a known product through its method of manufacture does not make that product novel. The European approach also addresses whether the product can adequately be defined in another manner.
In Israel, the distinction between a claim to a manufacturing process and a claim to the product itself has direct enforcement consequences. Section 50(a) of the Patents Law extends protection for a patented process to the product directly obtained by that process. Section 50(b) further establishes specific evidentiary rules in proceedings alleging infringement of a patented process for producing a product, subject to its statutory conditions. These provisions should be considered when selecting claim categories for materials manufactured inside facilities to which the patent owner will not have direct access.
The availability and construction of product-by-process claims remain questions to assess under Israeli law and Israeli patent practice. The EPO Guidelines on product-by-process claims provide comparative guidance for European filings. Markush and product-by-process claims under Israeli law are discussed in Yonatan Drori, Patent Law (Hebrew, 2023), Section 5.3.3.
Experimental Data: How Can the Technical Difference Be Demonstrated?
In chemistry and materials science, experimental results may provide the central support for an asserted technical advantage.
Suppose a company develops a polymer blend with improved thermal resistance. If it seeks claims covering a broad family of blends, a single experiment on one composition may not adequately establish that the benefit extends to all combinations within the proposed claims.
The drafter must consider whether the benefit occurs across the claimed compositions and whether the change in properties results from the inventive feature or another factor, such as the way in which the test sample was processed.
Often the most relevant comparison is not between the new material and an unrelated commercial product, but between the invention and a comparable material lacking the particular component or processing condition alleged to be inventive.
For example, if an additive is said to improve a polymer’s thermal stability, comparing otherwise identical formulations with and without the additive can help isolate its contribution.
The EPO Guidelines on inventive step and selection inventions emphasize the relationship between a claimed technical advantage and the breadth of the claim. An advantage shown only for part of the range will not necessarily support the entire range.
Experimental programs should therefore be planned with claim drafting in mind: which comparisons distinguish the invention from the prior art, and which data support the proposed scope of protection?
Claim Construction in Chemical Patents: Why Precise Language Matters
A seemingly small difference between chemical substituents or structural definitions may significantly affect the scope of protection.
In Israeli District Court proceedings involving Monsanto, the wording of the patent claims and the interpretation of chemical features from the perspective of a person skilled in the art were emphasized.
The practical implication is that the drafter should identify which chemical characteristics are essential, which components may be substituted and which limitations could permit a competitor to develop a chemically different material achieving a similar function outside the claims.
Section 12 of the Israeli Patents Law imposes a sufficiency-of-disclosure requirement. The specification must enable a person skilled in the relevant field to carry out the invention based on the disclosure and the person’s professional knowledge. Complex chemical inventions may require knowledge spanning several specialized disciplines.
Further discussion of chemical claim construction and sufficient disclosure appears in Drori, Patent Law (2023), Chapter 3.3 and Section 5.2.3.
Choosing Protection for a Material, Its Structure and Its Manufacturing Process
When drafting a patent application in chemistry or materials science, the central question is whether the technological contribution resides in the composition, the structure of the material, the manufacturing process or a combination of these.
This choice has commercial consequences. Where the composition of a competitor’s product can be determined through laboratory analysis, a composition claim may be easier to enforce. By contrast, establishing infringement of a process claim directed to manufacturing inside a closed factory may be more difficult.
In some cases, counsel should also consider the relationship between patent protection and retaining process know-how as a trade secret. However, information necessary to satisfy disclosure requirements cannot simply be omitted in order to preserve secrecy.
These decisions form part of a broader strategy for patent registration and prosecution in Israel and internationally. The aim is to secure protection that reflects the actual technical contribution and the manner in which the resulting material is expected to be manufactured, marketed and used.
Related guidance: How to Draft an Independent Patent Claim and Patent Drafting in Biotechnology and Pharmaceuticals.
