carreducker Renia Video

YouTube video posted by carréducker with an overview of products by Renia’s president, Rainer Buccholz

Notes

• company began in shoe repair, but since that has declined, branched out into orthopedic, bespoke, saddlery, and leathercraft
• Acquired SIEMA in 2018. They handle shoe industry.
• describes Top-Fit as the go-to cement for soling
• notes that entire line of solvent-based adhesives is replicated in their water-based Aquilim line

Industry versus Bespoke

• typically similar materials
• work in different ways
• industry needs primers for everything
• industry double coats, let dry completely, reheat, join, sometimes cooling tunnels
• industry likes hot melts, e.g. for lasting, where bespoke would use rubber cement
• Industry doesn’t hammer. They always press.

Rubber Solution

• natural rubber
• shoemakers used to make it themselves
• put shavings in benzene
• very hazardous solvents!
• plantation rubber / plantation crepe
• basically a weak contact adhesive
• i.e. coat both sides, let cure, bring in contact, it bonds
• bonds usualy stitched through
• allows some adjustability without damage
• doesn’t stick to needles or threads

Water-Based

• same basic raw materials with similar functions
• can replicate nearly any solvent-based adhesive in water-based
• Hirschkleber is a starch paste, also water-based
  • different purpose
  • similar to adhesives for paper bonding
  • stiffen as they cure

Contact Adhesive

• mostly two classes
  • polyurethane
    • dominant in industry
    • heat-activated
    • needs lots of pressure
    • bonds synthetics well
  • polychloroprene (CR)
    • “neoprene” a trademark of DuPont
    • plus resins, adhesion promoters
    • also in water-based

Renia Line

• each has its place
• rubber solution for uppers, lasting
• paste for toes and heel counters
• contact adhesives for soling, some upper construction
• leather to leather, leather to rubber: Top-Fit, probably strongest for that
• add PVC, vinyl, thermoplastic rubber, polyurethane: Colle de Cologne (modified polychloroprene) or Syntic-Total (polyurethane)
• thermoplastic rubber demands a primer

No Fume Extraction?

• use Aquilim (water-based) products
• solvent-based can be safe if used the right way, but may not be possible in particular environments
• water-based can’t do everything

Wet Leather?

• Top-Fit

Performance

• rubber solution
• Aquilim SG: PVA-based, pressure-sensitive, never cures, always sticky, works one-sided

Relocating

• peeling: rubber solution, Aquilim SG
• sliding: have to work with adhesive wet, but much longer drying time

Health and Safety

• solvent-based from anyone is hazardous
• MSDS
• e.g. no open flames, electrostatic discharges
• some still have toluene, MEKs
• less hazardous than 1950s, but don’t have a place today, especially toluene
• easy replacements, especially dangerous
• toluene: harmful to fetuses
• easiest way to bring down concentration: fume extraction or ventilation
• water-based can still cause allergic reactions

Environment

• adhesive content in shoes small
• have regulations on solvent per pair
• but so many exceptions
• biggest one: manufacture even worse, somewhere else
• most inputs are fossil-based
• are plant- and animal-based products, but currently don’t work as well
• long chemical industry supply chains
• can calculate impacts, but it’s complex and expensive
• don’t pour unused adhesives in the sink
• many emissions break down when exposed to sunlight in atmosphere
• carbon dioxide and water
• solvent evaporation concern is workplace safety first
• air exhaust treatment
• don’t have to do it at their factory

Future

• big forces pushing toward green approach
• plant-based resins
• large-scale manufacturing has shifted to water-based
• repair, bespoke, small manufacturers still using solvent
• “make stuff repairable” not yet in shoes
• bonding recycled materials can be challenging
• really cheap shoes can’t be made sustainably
• need to shift from consumption item to investments