Why Your Labels Aren't Sticking And How To Fix It？

 

In industrial production, warehousing and logistics, retail consumption and other scenarios, labeling or adhesive failure not only affects the efficiency of information transfer, but also may lead to compliance risks - such as chemical labeling leading to safety accidents, or food packaging label residual offset triggering consumer complaints. According to industry data, more than 60% of labeling failures are due to improper surface treatment or material selection. In this paper, we will analyze the scientific principles, practical solutions to the industry to help you accurately solve the problem of labeling.

 

 

 

 

1. What Causes Labels to Not Stick?

1) Surface contamination
Even if the naked eye clean surface, there may be residual grease, dust or water vapor. For example, warehouse shelves are often due to equipment lubricants evaporate to form a film of oil invisible to the naked eye, the surface of food packaging may be residual mold release agent. These contaminants can block the molecular contact between the adhesive and the substrate, leading to the label edge to take the lead in warping. One logistics company had 15% of its shipping labels fall off in transit due to uncleaned pallet grease, and eventually reduced the problem to less than 3% by wiping the pretreatment with isopropyl alcohol.
2) Curing time misconceptions
Most labels require 24 hours to complete the adhesive curing process. Rapidly putting them into use (e.g., handling them immediately after labeling) is likely to cause the adhesive layer to break due to external forces. Typical case: A cosmetic factory packed the labeled bottles in advance to meet the deadline, and the next day found that 20% of the label edges were curled, resulting in a loss of more than ten thousand US dollars.
3) Adhesive type mismatch
Adhesive selection needs to match the strength of the scene:
● Permanent adhesive: suitable for industrial equipment nameplates, outdoor billboards, using acrylic adhesive or rubber-based adhesive, tensile strength up to 50N/cm² or more.
● Removable adhesives: retail price labels, medical record stickers need to use low-tack silicone, no residue after peeling.
● Specialty adhesives: automotive engine compartment labels need to withstand high temperatures up to 200°C, labels for laboratory reagent bottles need to pass acid and alkali corrosion tests.
4) Material and environmental mismatch
Label material determines environmental tolerance:
● Low-temperature scenarios: -18 ℃ cold storage need to use freezer-grade PET material, ordinary coated paper will be brittle due to water absorption and peeling.
● Outdoor scenarios: UV resistant vinyl can withstand 2000 hours of sunlight testing with less than 5% fade rate.
5) Temperature Extremes Challenge
Temperature extremes directly alter the physical state of the adhesive:
● Low Temperature Failure: Ordinary pressure-sensitive adhesives will harden and lose adhesion below 0°C. Misuse of standard labels in an ice cream factory resulted in labels falling off in their entirety after being stored at -25°C.
● High-temperature failure: silicone-based labels are required for oven equipment, and ordinary adhesive will carbonize and become brittle above 80℃.
6) Chemical erosion
In chemical and medical scenarios, labels are often exposed to alcohol, solvents or disinfectants. A biological laboratory has been due to the use of ordinary labels, in 75% alcohol wiped within 3 days after the text fuzzy, the edge of the crimp, change to fluorocarbon coated labels after the number of wipe resistance to enhance to more than 500 times.
7) Surface Texture
Rough surfaces such as wood and corrugated plastics require "aggressive adhesives" - such layers contain micron-sized filler particles that can be embedded in surface gaps of 0.1-0.5mm. After a furniture manufacturer upgraded its sheet labeling adhesive to a grid-textured structure, shedding rates plunged from 20% to 3%.
8) Insufficient Adhesive Pressure
When applying labels by hand, finger pressure generates only 0.1-0.3kg/cm², whereas ideal adhesion requires more than 0.5kg/cm². It is advisable to use a plastic squeegee to push the label from the center to the edges at an even rate, or to purchase a small rolling machine (e.g. label laminator) to ensure even pressure.
9) High humidity
When humidity exceeds 70%, ordinary paper labels can cause the adhesive to break as the fibers expand. After a bathroom brand switched to polypropylene (PP) labels, the labels remained intact for more than 6 months in a 40°C high humidity test environment, while the original paper labels lasted only 2 weeks.
10) Outdoor aging
Qualified outdoor labels pass a triple test:
● UV test: 3 years of simulated sunlight (500kJ/m²) with a color delta E <3;
● Rain test: 50mm/h of rain for 2 hours with no warping of the edges;
● Temperature difference cycle: -30℃ to 80℃ cycle 50 times, adhesive strength retention rate>90%.

 

2. Ways to Fix Label Adhesion Issues

 

(1) Quick repair
● Deep Cleaning: Dampen a lint-free cloth with 75% isopropyl alcohol and wipe the surface in the same direction to ensure no oil residue (for smooth substrates such as metal and glass).
● Extended resting: labeled with "24 hours curing" warning, low temperature environment can be extended to 48 hours.
● Local reinforcement: For warped labels, a small amount of silicone adhesive can be applied to the edges (must be compatible with the original label).
(2) Material Upgrade

Scenario Requirements	Recommended Adhesive Type	Substrate Selection	Additional Properties
Industrial equipment labeling	Permanent acrylic adhesive	PET + matte coating	Oil-and scratch-resistant
Fresh food refrigeration labels	Low-temperature rubber-based adhesive	Frozen grade PP	-40℃ Anti-brittle
Cosmetic Bottle Labels	Removable Water Adhesive	Transparent PVC	Easy Peel, No Residue
Chemical Drum Warning Label	Chemical Resistant Silicone	Vinyl + Fluorocarbon Coating	Acid & Alkali Resistant, Solvent Resistant

(3) Professional Collaboration
It is recommended that the following information be provided to the labeling vendor:
● Substrate samples: e.g., shaped bottles, special textured sheets for easy testing of adhesive fit;
● Environmental parameters: including temperature intervals, frequency of chemical exposure, length of outdoor exposure;
● Application frequency: manual labeling or mechanical assembly line, which affects adhesive drying speed selection.
● A medical device company has customized 135℃-resistant, alcohol-resistant PP labels by providing the sterilization process (high-temperature and high-pressure steam) to its suppliers, completely solving the problem of label peeling off after sterilization.

 

3. Common application scenarios of labels

(1) Warehousing and logistic
● Pallet labeling: using permanent rubber-based adhesive + PET material, surface covered with anti-friction coating, can withstand forklift collision and winding film pulling;
● Cold chain labeling: -25℃ environment choose polyurethane (PU) substrate, the adhesive needs to be FDA approved (for food-grade pallets);
● Dangerous Goods Labeling: GHS compliant labels need to use fluorescent color ink + tamper-proof design, and display the word "VOID" when torn by external force.

 

(2) Food Retail:
● Fresh food labeling: removable starch-based adhesive + biodegradable paper, adhesive residue <0.1mg/cm² when peeled off, meets EU food contact standards;
● Ready-to-eat packaging: refrigeration-resistant (4℃) labels need to use water-resistant white ink to avoid condensation infiltration leading to blurred graphics;
● Environmental trends: a coffee brand launched "plantable labels", peeled off and soaked and germinated can grow into vanilla plants, user repurchase rate increased by 12%.

(3) Medical laboratory:
● Sample test tubes: cryogenic (-80°C) liquid nitrogen environment using nylon substrate + acrylic adhesive, resistant to more than 10 freeze-thaw cycles;
● Pharmaceutical packaging: child-resistant opening labels with "Pressure Sensitive + Tear Mark" design, requiring more than 2kg of vertical force to peel off;
● Sterilization scenarios: autoclave (121°C, 30 minutes) labels need to be made of polyimide (PI) with a shrinkage rate of <0.5%.

(4) Outdoor equipment:
● Mountaineering equipment: sunscreen, sweat erosion environment selection of silicone rubber + PETG material, friction resistance test (500 times wipe) after the graphic clarity> 95%;
● Automotive components: engine compartment labels using 250 ℃ resistant polytetrafluoroethylene (PTFE), with pressure-sensitive adhesive to achieve "immediate paste curing";
● Marine equipment: a yacht brand uses 316 stainless steel etched labels to replace traditional stickers, which can withstand seawater immersion for more than 5 years without corrosion.

4. Frequently asked questions

Q1: What if the edge of the label continues to curl?
Check the curvature of the substrate: Curved containers should be made of stretchable material (such as PE film) to avoid cracking of rigid PVC due to stress;
Optimize the design: change the right angle labels to R5mm rounded corners to reduce the stress concentration at the edges;
Environmental control: When the humidity is >60%, the storage environment needs to be equipped with dehumidifiers (target humidity 45%-55%).
Q2:Transparent labels show fingerprints affecting aesthetics?
Material selection: matte PET is less likely to show fingerprints than glossy PVC;
Operation standard: Wear cotton gloves or finger cots, avoid touching the adhesive surface directly;
Surface treatment: add anti-fingerprint coating (AF coating) when printing, and reduce the coefficient of friction to below 0.2.
Q3: Can waterproof labels really be soaked in water?
Short-term waterproofing: High quality PP labels can withstand 24 hours of immersion (e.g. beer bottle labels), but long-term underwater environments (e.g. diving equipment) require the use of vulcanized rubber labels;
Test standards: through the ASTM D570 water absorption test, the weight increase after 24 hours of immersion <1.5% is qualified.

 

Labeling failures may seem small, but they can trigger a chain reaction - from the direct loss of product recalls to the hidden loss of brand trust. Instead of reactively remedying the problem after it occurs, it is better to establish a three-dimensional matching system of "material - environment - technology" at the source.
YuCai, as the industry's leading label manufacturer, is your partner. Contact our professional team to customize your labeling solution and make every label a guardian of safety and efficiency.