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The question is explicitly aimed at paper electronics. No classic/typical PCB (fiber glass or typical material PCB's are made of) is attached to the paper. The circuit layout is directly printed/fabricated onto the paper. The components are also fabricated onto paper (not necessarily printed onto the main PCB, It could be separately manufactured and then attached). All the components are thin film and material exist of some conductive/semi conductive/dielectric polymers, metallic ink, metallic salts and metallic oxide ink mixtures.

The question has two branches, which depends on how expensive the final product will be and at the same time prevents to over complicate the assembly process for the user.

Pre-assembled

Shipping a piece of paper as an assembled circuit with semiconductor components that are capable of oscillating above 9kHz and even potentially into the MHz range. The same conditions hold as in the intro but all components are already attached/stuffed on to the main PCB, it only needs a power source to start operating.

Components are not stuffed on to the main PCB

The components are contained on the same paper, but no electrical connection during shipping. It needs to be removed and then being glued back on to the main circuit board with some conductive glue or paint. Again this is thin film printed components that can perform the same function as standard shelf components.

More Info

To refine the assumptions further. It will contain no Cadmium and Mercury or other harmful substances, so RoHS should easily be satisfied, but still wants to prevent RoHS certification. Some components may have RF capability 2.4GHz, but no Bluetooth or WiFi for now. The user much supply its own power source, it won't have standard sockets.

Possibility of adding thin film batteries

I want to expand the scope just a bit, but this should not be the focus of the question. How does it effect the overall requirement by adding zinc graphite, some organic electrolyte + manganese electrode to form a thin film battery/capacitor onto the paper.

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    \$\begingroup\$ Same requirements as for any PCB: EMC, RoHS, WEEE and so on directives. In case it contains RF parts then also RED and LVD. \$\endgroup\$
    – Lundin
    Jul 5, 2022 at 13:39
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    \$\begingroup\$ An initial question you should ask yourself: do any of the laws on the matter specifically mention FR4 or another traditional substrate? If not, why would paper be a special case that differs from following that law the same way you would for any other substrate? \$\endgroup\$
    – nanofarad
    Jul 5, 2022 at 13:43
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    \$\begingroup\$ The fact it's paper based has no bearing on the certification required. The RoSH REACH, saftey, CE will be required for the EU (and UKCA for the UK). There is a similar range for the US: UL and FCC marking and certification will be required. Adding batteries always complicates matters, but that depends on the chemistry, which you don't seem sure of yourself, so that can't be answered eaisly here. \$\endgroup\$
    – Puffafish
    Jul 5, 2022 at 14:15
  • \$\begingroup\$ It is much more apparent now that the substrate type is irrelevant regarding certification, but rather how it behaves. In that regard I have receive some useful answers. I was hoping to market it as something else than a PCB since it is paper, but that also accounts for any PCB type, so paper has no advantage it seems. I also embedded in my post another method to avoid certification, which is also not specific to paper. Some of the posted answers also addressed that particular. \$\endgroup\$
    – HackEagle
    Jul 6, 2022 at 7:47

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FR stands for “flame retardant” and indicates that the material is compliant with the UL94V-0 standard on plastic material inflammability. The 94V-0 code can be found on all FR-4 PCBs. It guarantees the non-propagation of fire and its rapid extinguishing when the material burns.ref

There are more rules regarding toxicity and disposal and differences between EU and USA. https://www.allaboutcircuits.com/news/how-europe-and-us-take-different-stances-pcb-material-regulation/

This seems like a good idea for a flexible printed circuit board until you consider the faults in fire retardant ratings or the trace reliability due to repeated flexures from shearing or microcracks.

Although fiberglass reinforced paper (cellulose) PCBs rated for FR4 (fire retardant level 4) are still popular in one-sided PCBs, low-cost, high-volume, low-density applications. Bromide is used as an additive in FR4 for flame retardant.

The preferred choice for flex printed circuit (FPC) material is a polyurethane tradename Kapton that comes in rolls with many options.

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  • \$\begingroup\$ This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. - From Review \$\endgroup\$
    – Jens
    Jul 5, 2022 at 21:25
  • \$\begingroup\$ TY @Jens The implied answer is that paper is not FR4 compliant unless treated. \$\endgroup\$
    – Tony Stewart EE75
    Jul 5, 2022 at 21:55
  • \$\begingroup\$ OK, I understand \$\endgroup\$
    – Jens
    Jul 5, 2022 at 23:01
  • \$\begingroup\$ Although it only addresses a particular part of certification, it is still relevant and useful to the question and particular meaningful to what I am trying to accomplish. Even if certification can be avoided, the product should still be absolutely safe. \$\endgroup\$
    – HackEagle
    Jul 6, 2022 at 7:55
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The components are contained on the same paper, but no electrical connection during shipping. It needs to be removed and then being glued back on to the main circuit board with some conductive glue or paint.

This allows you to circumvent quite a lot, because it becomes a "kit" and doesn't require RF emissions testing or most of the ETSI tests. I'm not sure if it even still requires CE marking.

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  • \$\begingroup\$ That was also my initial thoughts. But it turns out that a kit still produces an end product to the user and can even makes certification even more difficult, since I have no quality control over the "manufacturing" of the final product. The key is to market it as a "sub-assembly" according to Andy Eadie \$\endgroup\$
    – HackEagle
    Jul 6, 2022 at 8:15

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