Hui HU | Jan 18, 2019

For an invention application of materials, the inventive concept thereof, as a core, effectively  connects four items, i.e. the technical field, the technical problem to be solved by the application, the technical solution and the advantageous effect. In a response to an inventive-step Office Action, these four items should be considered as a whole to determine the inventive concept of the technical solution. Then, the technical principle should be expounded, and the inventive- step of a claim should be further argued following a“three-step” approach.

Introduction
In order to assess the inventive-step of an invention application, two parts, i.e.“prominent substantive features” and “notable progress”, would be examined. It is one of the keys to argue the non-obviousness of a technical solution for responding to an inventive-step Office Action in a “three-step” approach. For this, the technical solution should be considered as a whole, but should not be split into individual elements. In fact, both of the claimed invention and reference document(s) should be viewed respectively as an inseparable whole.
Clarifying the inventive concept of an invention application is crucial for understanding the claims and technical solutions cited therein. For an invention application of materials, it is also crucial to determine and understand the inventive concept, which is the soul of the application, for responding to objections raised, especially to inventive-step objections. Therefore, in order to get a grant of an invention application of materials, it is indispensable that the inventive-step of the application is argued following the “three-step” approach by connecting the technical field, the technical problem to be solved by the application, the technical solution, and the advantageous effect along the inventive concept, considering them as a whole and expounding the technical principle implied by the inventive concept.

Use of inventive concept in a response to an inventive-step objection
Case
Application No.: 2013104595492;
Title of invention: A preparation method of microcapsule- coated ammonium polyphosphate with low viscosity.
In the first Office Action, the examiner cited two reference documents:
D1, CN102936429A; and D2, CN 102827399A.
According to the examiner, the technical solution of claim 1 differed from that of D1 in that: (1) a blocking agent was added after a coating reaction in the claimed invention, while a formaldehyde catching agent was added in D1; and (2) cooling conditions and drying time after the reflux reaction of the claimed invention were different from those of D1. The technical problem to be solved by the claimed invention was how to reduce the viscosity of melamine formaldehyde resin coated ammonium polyphosphate.
 
Regarding the distinguishing technical feature (1), the examiner indicated that D2 provided a technical inspiration of adopting a solvent such as ethanol as a dispersing agent. Generally, the skilled person would be motivated to add ethanol, which functions as a dispersing agent, after the coating reaction. In addition, ethanol is a specific term of the blocking agent and the formaldehyde catching agent can be added or not added.
Regarding the distinguishing technical feature (2), the examiner considered that it only belonged to conventional adjustment and selection of parameters.
On this basis, the examiner deemed that claims 1-8 lacked inventive step.
After receiving this Office Action, we made careful analysis and evaluation. We incorporated the technical features of original claims 2-8 into claim 1 and further defined the blocking agent.
First, we analyzed the inventive concept and technical principle of the claimed invention, in combination with the existing technical problem in the prior art. In the prior art, when ammonium polyphosphate is coated with melamine formaldehyde resin prepolymer, the coating layer would form many branches, the surface thereof would thus be irregular and the gap in the powder would be increased: that results in relatively high viscosity in practical applications. However, both D1 and D2 do not provide any technical inspiration for solving the technical problem of the irregular surface of the coating layer of ammonium polyphosphate powder.
The inventive concept of the claimed invention
In order to overcome the above problem in the coating process, melamine formaldehyde resin prepolymer is used in the claimed invention to perform microcapsule-coating, and the blocking agent is added at a later stage of the reaction to inhibit crosslinking, thereby ensuring the uniformity of the surface of the coating layer, i.e. producing significant technical effect.
According to the above inventive concept, the distinguishing technical features between claim 1 and D1 are determined as following:
(1)the blocking agent is added after dropping a curing agent and performing a reaction; and
(2)the reaction parameters are different from those of D1.
The technical principle of the claimed invention is that: when the ammonium polyphosphate powder is coated with melamine formaldehyde resin prepolymer, the curing of the resin prepolymer would continue during the reaction, and a part of active groups such as hydroxymethyl group would be still exposed at the surface and continue to crosslink even though the powder has been coated. As a result, many branches of different length are formed at the surface of the coating layer, which makes the surface of the coated powder particles “rough and thorny”. Thus, the coated particles cannot be packed densely, and the viscosity thereof is relatively high in practical application.
 In the claimed invention, the crosslinking can be inhibited by the added blocking agent, and the resulted coating layer is uniform. Direct experimental evidences are provided in the description of the claimed invention. The following are SEM images (i.e. Figs. 1 and 2) of the products of Examples 1 and 6 of the claimed invention.

Fig. 1

Fig. 2
 
From the two images on the previous page, it can be seen that the coated ammonium polyphosphate, which is processed with the blocking agent, has a uniform surface (as shown in Fig. 1) and no redundant branches. In contrast, the coated ammonium polyphosphate, which is not processed with the blocking agent, has a rough surface (as shown in Fig. 2) and branches at the surface. In addition, it can be seen from the test data of solubility (see Table 1 of the description of the claimed invention, which is shown as follows) that the products of the claimed invention have higher water insolubility. That is, the coating of the products of the claimed invention is complete and is also uniform and smooth.

In contrast, D2 neither discloses that many branches at the surface of the coating layer can be solved by adding the blocking agent, nor provides any technical inspiration for it.
Second, it is sufficient to prove the non-obviousness of the claim 1 by arguing the distinguishing technical features based on the technical principle of the claimed invention, provided that the inventive concept of the claimed invention and the principle of the technical solution have been clarified.
 
In the second Office Action, the examiner raised again that, though the solvent cited by D2 functions as a dispersing agent, it has substantially the same function as that of the blocking agent of the claimed invention. Regarding the comments of the examiner, the applicant provided targeted responses again based on the technical principle. Particularly, the applicant provided the following argument for the distinguishing
technical features.
In D2, the dispersing agent is added into a reaction system of melamine formaldehyde resin prepolymer with a slurry obtained from the first step, with the purpose of reducing the viscosity of the reaction system. The reactive materials in the system have certain molecular weight and many polar groups. Among the polar groups, there would be strong interaction, association of hydrogen bonds and Van der Waal’s force, resulting that the reaction system is very viscous and harmful to the coating. Thus, the incorporation of the solvent (any one of water, ethanol, acetone and ethylene glycol) can reduce the solid content of the system, so as to “dilute” various acting forces, uniformly disperse the reacting materials to avoid the aggregation, and thus enhance the efficiency of the reaction.
That is, the dispersing agent of D2 as a solvent is actually used to reduce the viscosity of the reaction system. The dispersing agent of D2 performs a physical function and acts on a mixture system formed by the melamine formaldehyde resin prepolymer with ammonium polyphosphate slurry. Thus, the dispersing agent of D2 has the same function as that of the solvent of the claimed invention.
Obviously, the blocking agent of the claimed invention is not used to reduce the viscosity of the reaction system and does not perform a physical function. In fact, the blocking agent reacts with the exposed polar groups, such as hydroxymethyl, of the coated product (i.e. a product in which ammonium polyphosphate has been coated with the melamine formaldehyde resin prepolymer) to inhibit the crosslinking, thereby preventing the active groups at the surface of the coated product from “growing” into “big arms” (i.e. forming branches) due to crosslinking, preventing the formation of “acanthosphere”, which increases the distance between the particles in the surface microstructure of the final powder product and further preventing too high viscosity of the final powder product during the practical processing (e.g. during the processing of modified plastic), which is harmful to the dispersing in the matrix.
As can be seen, the function of the blocking agent of the claimed invention is to react with the active groups exposed at the surface of the coated product, so that the resulted surface is smooth and uniform, the gap in the powder is decreased, and the powder is dense. Thus, the viscosity is decreased during the practical application. That is, the function of the blocking agent of the claimed invention is different from that the dispersing agent of D2, which is used to decrease the viscosity of the reaction system.
In summary, we started with the inventive concept, analyzed the technical principle of the technical solution, finally focused on the distinguishing technical feature, i.e. the blocking agent, and fully explained the function thereof in the claimed invention. We argued that the blocking agent of claim 1 performed a quite different function from that of the solvent of D2 which functions as a dispersing agent. In view of this, we argued the technical solution of claim 1 is not obvious with respect to the prior art. We also argued the technical solution of the claimed invention has prominent progress with respect to the prior art, in combination with the experimental data and evidence. On this basis, we sufficiently demonstrated the inventive step of claim 1. The claimed invention was finally granted a patent right.

Conclusions
1. In a response to an inventive-step Office Action of an invention application of materials, the technical solution of the application shall be considered as a whole, and not be split into separated elements. Meantime, the inventive concept thereof is the clue and can be used to connect the technical problem, technical solution, and advantageous effect.
2. For an invention application of materials, the inventive concept thereof can be determined by analyzing the distinguishing technical feature(s) between the technical solution of the application and that of the reference document. Thus, the determination of the inventive concept has “weathervane” effect for the response to the Office Action.
3. In order to overcome “ex post facto” prejudice of the examiner,it is helpful for the examiner to fully understand the inventiveconcept by expounding the technical principle during a response to an inventive-step Office Action in a “three-step” approach. With the inventive concept in the mind, the examiner would assess whether the distinguishing technical feature(s) is/are obvious over the prior art, without strong subjectivity.