MATERIAL-LAYER TECHNICAL DOSSIER
Protective PHBH Film
A transparent barrier separates the active layer from abrasion, water and direct contact.

01 · PRINCIPLE & RATIONALE
Intended function
and associated requirement.
A transparent barrier separates the active layer from abrasion, water and direct contact.
Enables the thermochromic signal to remain contained throughout the use cycle.
Thickness, haze, permeability, adhesion, toughness and thermal stability must protect without excessively delaying the signal.
02 · TECHNOLOGY STACK
Technologies, roles
and approval gates.
Material and process qualification
- Role
- Converts the design basis into a repeatable specification.
- Why
- Performance depends on the real commercial grade and process window.
- Approval gate
- Documented test evidence and approved specification.
03 · ARCHITECTURE
Function, material
and interfaces.
The film must remain inseparable in use and create no raised edges or accumulation points.
- Layer L06
- External environment
- Seal to L02
- Vision system
- 01Transparent film
- 02Sealed perimeter
- 03No free edge
- 04Continuous barrier
04 · MASTER PARAMETER REGISTER
Everything to be defined,
measured or certified.
A field without evidence is never filled with an invented number: it remains “To be determined”, together with the method required to close it. This is what makes the technical record verifiable.
01Identification & function1 PARAMETERS
| ID | Parameter | Symbol | Value | Unit | Tolerance | Condition | Method | Status |
|---|---|---|---|---|---|---|---|---|
| L07-X001 | Intended use | USE | To be determined | — | To be defined | Full use cycle | Design review + user study | TO BE VALIDATED |
02Geometry & metrology1 PARAMETERS
| ID | Parameter | Symbol | Value | Unit | Tolerance | Condition | Method | Status |
|---|---|---|---|---|---|---|---|---|
| L07-X002 | Nominal mass | m | To be determined | g | To be defined | 23 °C / 50% RH | Balance 0.001 g | TO BE VALIDATED |
03Material1 PARAMETERS
| ID | Parameter | Symbol | Value | Unit | Tolerance | Condition | Method | Status |
|---|---|---|---|---|---|---|---|---|
| L07-X003 | Commercial grade and supplier | GRADE | To be determined | — | Qualified grade | Production lot | CoA + traceability | TO BE VALIDATED |
04Thermal properties1 PARAMETERS
| ID | Parameter | Symbol | Value | Unit | Tolerance | Condition | Method | Status |
|---|---|---|---|---|---|---|---|---|
| L07-X004 | Service-temperature range | Tservice | To be determined | °C | To be defined | Use and transport | Climate chamber | TO BE VALIDATED |
05Mechanical properties1 PARAMETERS
| ID | Parameter | Symbol | Value | Unit | Tolerance | Condition | Method | Status |
|---|---|---|---|---|---|---|---|---|
| L07-X005 | Drop resistance | Hdrop | To be determined | m | To be defined | Defined orientations | Instrumented drop test | TO BE VALIDATED |
06Quality control1 PARAMETERS
| ID | Parameter | Symbol | Value | Unit | Tolerance | Condition | Method | Status |
|---|---|---|---|---|---|---|---|---|
| L07-X006 | Process capability | Cpk | To be determined | — | Target to be defined | Critical CTQ | SPC ≥30 samples | TO BE VALIDATED |
07Food contact1 PARAMETERS
| ID | Parameter | Symbol | Value | Unit | Tolerance | Condition | Method | Status |
|---|---|---|---|---|---|---|---|---|
| L07-X007 | Overall and specific migration | MIG | To be determined | mg/kg | Applicable limits | Simulant/time/temperature | Accredited methods | TO BE VALIDATED |
08Recyclability1 PARAMETERS
| ID | Parameter | Symbol | Value | Unit | Tolerance | Condition | Method | Status |
|---|---|---|---|---|---|---|---|---|
| L07-X008 | Territory-specific end-of-life route | EOL | To be determined | — | Country/area defined | Complete assembly | Infrastructure mapping | TO BE VALIDATED |
05 · INDUSTRIALISATION
From material
to final inspection.
Qualified material
Transparent PHBH cover film
Process within window
Film forming + perimeter sealing
Controlled interfaces
Layer L06 · External environment · Seal to L02 · Vision system
CTQ + traceability
Cutting, placement, sealing and vision inspection must create a continuous barrier around the patch.
06 · DVP&R
A function is approved
only after passing its test.
| Test | Requirement | Risk | Method | Condition | Samples | Acceptance | Output |
|---|---|---|---|---|---|---|---|
| DVP-05 | Condensation management | Wet grip | Climate + gravimetry | 25 °C/60% RH; water 4 °C | 30 | ≥60% less retained water | Mass + images |
| DVP-06 | ThermoSnow | Incorrect threshold | Thermal/colour cycles | 0–25 °C | 30 | 8±2 °C; ≤15 s | ΔE/T curves |
| DVP-12 | Food contact | Migration/NIAS | Overall/specific migration | Cold-fill water use | 3 lots | Applicable regulatory compliance | Signed report |
07 · FAILURE MODES
Failure modes,
causes and controls.
Body brittleness
EffectBreakage/leak
CausePHA thermal window
ControlDSC/TGA, rheology, process DOE
Non-uniform walls
EffectBuckling/drop failure
CauseAsymmetric geometry
ControlBlow-moulding CAE + micro-CT
AeroSkin detachment
EffectLoss of function/loose part
CauseInsufficient seal
ControlPeel, thermal cycling and drop
08 · EVIDENCE POLICY
Traceability
for every parameter.
Avoids metal supports and electronics; compatibility with the PHA route remains to be demonstrated on the full stack.
This page is the technical register for the R2 configuration. It separates design values, targets, calculations, measurements and certifications. Open fields identify the exact test or document required to close them.