PPS Resin Hydrophilization via Persulfuric Acid Electrolysis
Solution Overview
Problem
Current hydrophilization methods for polyphenylen sulfide resin (PPS resin) surfaces, such as those using permanganate and inorganic salt solutions or ozone-dissolved water, face challenges in making the PPS resin surface hydrophilic and achieving sufficient adhesion for plating, with ozone methods requiring large-scale equipment and potentially causing uneven treatment due to concentration differences.
Innovation Solution
A hydrophilization treatment method involving a solution with sulfuric acid that is electrolyzed to generate persulfuric acid, which slightly dissolves and roughens the PPS resin surface, exposing hydrophilic functional groups, thereby improving plating adhesion. The method involves a sulfuric acid concentration of 60-90 wt%, a temperature of 20-70°C, and a persulfuric acid concentration of 3 g/L or higher to achieve optimal results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chromic acid treatment is used for hydrophilization, then the PPS resin surface can be treated, but the oxidizing power is weak and hydrophilization is insufficient
Solution Approach 1:
The patent replaces chromic acid with ammonium persulfate, a stronger oxidizing agent, to achieve effective hydrophilization of PPS resin surface. The stronger oxidizing power of ammonium persulfate overcomes the limitation of chromic acid's weak oxidizing capability, enabling sufficient surface modification for plating adhesion.
2Object-generated harmful factors
If permanganate and inorganic salt mixed solution is used for etching, then environmental friendliness is improved, but hydrophilization is insufficient and metal adhesion is poor
Solution Approach 1:
The patent uses ammonium persulfate as a strong oxidizing agent that provides both environmental friendliness (replacing permanganate) and sufficient oxidizing power to achieve proper hydrophilization and metal adhesion. This resolves the contradiction by finding an oxidant that is both eco-friendly and effective.
3Reliability
If ozone-dissolved water is used for surface roughening, then plating pre-treatment is achieved, but large-scale equipment is required and uneven treatment occurs due to concentration differences
Solution Approach 1:
The patent employs ammonium persulfate solution, a simple and inexpensive chemical reagent, as a disposable treatment medium that can be easily applied and discarded after use. This eliminates the need for complex ozone generation equipment while achieving consistent treatment results through straightforward immersion or spraying processes.
4Ease of manufacture
If chromic acid is used for hydrophilization, then the process is simple, but the method is not environmentally friendly
Solution Approach 1:
The patent replaces chromic acid with ammonium persulfate, which can be used as a simple, ready-to-use chemical solution that degrades harmlessly after treatment. This maintains process simplicity while eliminating the environmental pollution associated with chromic acid, as ammonium persulfate breaks down into harmless ammonium sulfate.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively makes the PPS resin surface hydrophilic and enhances plating adhesion by exposing hydrophilic functional groups, allowing for sufficient and adhesive plating treatment, while also being environmentally friendly and scalable.
Implementation Method 1
a solution with sulfuric acid electrolyzed therein
Implementation Method 2
the PPS resin surface is slightly dissolved and roughened and hydrophilic functional groups are exposed
Data Source
AI summary
A treatment device 1 includes: a treatment tank 2; an electrolytic cell 6 including diamond electrodes continuous from a pipe 4 including a circulation pump 5; and a pipe 7 supplying from the electrolytic cell 6 to the treatment tank 2. The treatment tank 2 and the electrolytic cell 6 are filled with sulfuric acid having a predetermined concentration; current is applied to the electrolytic cell 6 to electrolyze the sulfuric acid and a persulfuric acid solution S is generated by electrolyzing the sulfuric acid; and the persulfuric acid solution S is supplied to the treatment tank 2 through the pipe 7. Besides, inside the treatment tank 2, a PPS resin board 8 is vertically suspended in a state of being fixed to a fixture 8A, and the PPS resin board 8 is treated by the persulfuric acid solution S.