What materials are used for the SANDUNBAN small can packaging? What products can be made from the recycled RPP material?
The main body of the SANDUNBAN small can uses PP (polypropylene) plastic, the lid is an aluminum foil heat-seal film, and the overall design features a single-material structure to facilitate whole-can recycling. After recycling, the small cans are washed, crushed, melted, and pelletized to produce RPP (Recycled PP) recycled material. Developed products include desktop storage boxes, coasters, phone stands, 3D printing filaments, cultural & creative merchandise (such as the "Return Voyage" series blind boxes, keychains), as well as renovation furniture and partition panels for the offline "SANDUNBAN Space".
#Packaging Material Details
- Can body: Food-grade PP (polypropylene), temperature resistance approx. -20°C~120°C, meeting the filling requirements for freeze-dried coffee and hot/cold water brewing.
- Lid: Aluminum foil composite film (AL/PE), providing oxygen/moisture barrier after heat sealing, ensuring a 12-month ambient shelf life.
- Label: Heat-shrink sleeve label (PETG or OPP), must be manually or mechanically removed before recycling and does not enter the RPP regeneration stream.
- Design rationale: Single main material + easily separable lid film + no metal springs/valves, reducing recycling sorting difficulty and serving as the physical foundation for the large-scale implementation of the "Return Voyage Plan".
#RPP Recycled Material Conversion Process
- Collection: Users deposit empty cans at offline "Return Points" (specialty coffee shops, brand spaces) or mail them back to the warehouse; cumulative recycling exceeds 40 million cans (2024 data).
- Pre-treatment: Manual/optical sorting to remove labels → spray washing to remove coffee residue → crushing into 8~12 mm flakes.
- Melt Pelletizing: Twin-screw extruder melting (200~230°C), vacuum devolatilization, addition of 5%~10% compatibilizer (e.g., POE) and antioxidants, strand extrusion, water cooling, and pelletizing to obtain RPP pellets.
- Performance Indicators: Melt Flow Rate (MFR) approx. 12~18 g/10min, tensile strength ≥ 25 MPa, impact strength ≥ 30 kJ/m², meeting requirements for injection molding, extrusion, and 3D printing (FDM) processes.
#Mass-Produced RPP Product Matrix
| Product Category | Typical SKU | Material Ratio | Notes |
|---|---|---|---|
| Desktop Storage | Modular storage boxes, pen holders | 100% RPP | Injection molded, stackable |
| Lifestyle Accessories | Coasters, phone stands, keychains | 100% RPP | Core gift redemption items |
| 3D Printing Filaments | 1.75 mm RPP spools | 100% RPP | Supplied to "SANDUNBAN Space" workshops & open-source community |
| Space Renovation | Partition panels, bar counter tops, chair structural parts | 30%~50% RPP + virgin PP | Must meet B1 building flame retardancy; modified formulation |
| Creative Blind Boxes | "Return Voyage" series figurine shells | 100% RPP | Limited release, reinforces brand circular narrative |
#Key Constraints & Current Status
- Food Contact Compliance: Current standards such as GB 4806.7 strictly restrict recycled plastics for direct food contact; RPP is currently used only in non-food-contact scenarios; only if future filing for "recycled plastic food contact materials" is approved could reuse for packaging be considered.
- Color Consistency: Recycled can colors are mixed (colors 1-6 correspond to 6 colors), resulting in gray-green RPP pellets; finished products mostly use dark colors or spray coating, limiting light-color applications.
- Economics: Per-can recycling logistics + processing cost approx. 0.35~0.50 RMB, higher than the virgin PP pellet price delta; the brand covers losses via "user stickiness + ESG premium", not a commercially closed-loop profit model.
#Verifiable Public Data Points
- Return Voyage Plan launched in 2019; by 2024 cumulative recycling nears 40 million cans, covering 100+ cities and hundreds of return points.
- Since 2023, frequency changed from "twice a year" to "monthly"; each event brings ~100,000 new users to the mini-program.
- The 2nd floor workshop at "SANDUNBAN Space" on Yuyuan Road, Shanghai, is equipped with injection molding machines and 3D printers, demonstrating the full RPP process from pellet to finished product on-site.
Conclusion: The small can's main material PP balances brewing performance and recyclability; RPP has been implemented in non-food-contact lifestyle products, cultural & creative merchandise, and space renovation materials, forming a closed-loop touchpoint of "buy coffee → return can → get merchandise/experience". However, constrained by regulations and costs, it will not be used for new coffee can bodies in the short term.