- Core Principles for Selecting Materials for “Scrapable Labels”
The ease of removing a label largely depends on three key material properties: surface tension, surface hardness, and chemical stability.
Surface tension and smoothness: The smoother the surface and the lower the tension (e.g., laminated or coated surfaces), the harder it is for the adhesive layer to bond firmly, making scraping cleaner with little residue and minimal damage. In contrast, rough surfaces (e.g., untreated wood, frosted plastics) trap adhesive, making removal difficult.
Surface hardness: The hardness of the surface must match the “scraping tool” (cloth, plastic scraper, blade). If too soft (e.g., foam, soft rubber), the surface is easily damaged. If too hard (e.g., tempered glass, metal), the scraper must avoid slipping or scratching while still effectively lifting the adhesive.
Chemical stability: If alcohol, acetone, or other solvents are used to clean adhesive residue, the material must resist corrosion, deformation, or oxidation and remain non-toxic (especially for food-contact and children’s products).
- Material Options and Logic Across Different Scenarios
(1) Food-Contact Applications (food packaging, tableware, insulated bottles)
Core requirements: Food-grade safety, easy cleaning, temperature resistance (cold storage / heating), no residue risk.
Preferred materials:
Food-grade stainless steel (304/316): Smooth, dense surface; adhesive bonds only superficially; easy to scrape with a soft tool; withstands high temperatures (dishwasher-safe); no harmful release. Avoid metal blades to prevent scratches.
Borosilicate glass: High surface hardness (Mohs 6.5); labels (typically pressure-sensitive) can be loosened with warm water; residue removable with alcohol without corrosion. Transparent, odorless—ideal for jars and cups.
Food-grade PP plastic (polypropylene): Smooth surface, wide temperature tolerance (-20℃ to 120℃); labels often use removable adhesives, minimizing residue. Lightweight, durable, widely used in food containers and drink bottles. Avoid recycled or plasticizer-added PP to prevent deformation or toxic release.
Excluded materials: Soft PVC (may contain plasticizers), unpolished aluminum alloy (prone to oxidation and adhesive embedment).
(2) Home & Decorative Applications (furniture, appliances, wall finishes)
Core requirements: Aesthetic integrity (no trace after removal), scratch resistance, style compatibility.
Preferred materials:
Laminated MDF/particle board: Surfaces laminated with PVC or PET films are smooth and hard (abrasion resistance ≥400 cycles). Labels (pressure-sensitive) can be scraped with a plastic tool; residue removable with essential oils or mild solvents. Common in wardrobes, desks.
Matte/glossy painted metal (appliance casings): e.g., refrigerator or washing machine steel panels. Paint layer is smooth and chemically resistant; adhesive lifts easily; residue removable with alcohol (avoid strong solvents like acetone).
Washable latex-painted walls: Matte latex paint with “washability ≥1000 scrubs.” Paper-based labels can be moistened and scraped off; residues cleaned with erasers. Avoid textured or freshly painted walls.
Excluded materials: Unsealed solid wood (adhesive seeps into grain, removal damages surface), frosted plastics (rough texture traps residue).
(3) Industrial & Tool Applications (equipment housings, tool handles, pallets)
Core requirements: Wear resistance, impact resistance, adaptability to oil, heat, or outdoor exposure.
Preferred materials:
Cold-rolled steel plate (powder-coated): Common for equipment casings. Coating hardness ≥2H; industrial labels (thicker adhesive) can be peeled with a blade, residue removable with diesel without damaging coating. Durable against impact and corrosion.
Nylon 66 (tool handles): Glossy surface; labels (laser-printed or removable adhesives) can be scraped easily. Resistant to oils and aging; residues removable with diesel, suitable for hand tools.
HDPE plastic (high-density polyethylene): Used in pallets and outdoor housings. Smooth, solvent-resistant surface (resistant to acids, alkalis, organic solvents). Adhesive residue can be cleaned with any solvent. Performs well in low temperatures (-40℃) and outdoor environments.
