Self-adhesive labels, also known as pressure-sensitive label materials, are composite materials that use paper, film, or special materials as the face material, with an adhesive coated on the back and silicone-coated release paper as the backing paper. They are widely used in packaging, labeling, and advertising for their high adhesiveness and excellent printing quality.
1. Types of Self-Adhesive Labels
Self-adhesive labels can be broadly divided into two categories: paper-based materials and film-based materials.
- Paper-based Materials
Paper-based materials include coated paper, offset paper, kraft paper, glassine paper, laser paper, fluorescent paper, gold-plated paper, aluminum foil paper, tamper-evident (security) paper, silver-plated paper, textured paper, fabric label (Tyvek/Nylon) paper, pearlized paper, sandwich coated paper, variable information paper, etc.
Paper-based self-adhesive labels are widely used in liquid detergent products and mass-market personal care products.
- Film-based Materials
Film-based materials include transparent polyvinyl chloride (PVC), polyester (PET), polypropylene (PP), polycarbonate (PC), synthetic paper, PS, PE, Shape Memory Polymer (SMP) for security applications, and others.
Film-based self-adhesive labels are widely used in mid-to-high-end daily chemical products and come in three types: white, matte, and transparent.
1.1 Applications of Paper-Based Self-Adhesive Labels
- Coated Art Paper and Offset Paper Labels
These multipurpose label papers are suitable for information labels and barcode printing labels, especially ideal for high-speed laser printing, but also applicable for inkjet printing. They are mainly used for price tags for handwriting in supermarkets, tea shops, and other retail businesses.
- Coated Art Paper Self-Adhesive Labels
Coated art paper self-adhesive labels have a smooth and fine surface, which allows for fluid printing colors and strong color reproduction, satisfying most people's high requirements for print quality. Their advantages include low cost and broad printing adaptability, making them suitable for various industries and a top choice in the current market. The downside is that they are not waterproof, oil-resistant, or tear-resistant. However, after lamination, they can become waterproof, oil-resistant, and less prone to tearing.
Coated art paper self-adhesive labels can be used for pharmaceuticals, food, alcoholic beverages, electrical products, cultural goods, etc. (The paper surface is clean, smooth, and glossy). They can undergo lamination (glossy film, matte film, laser film, etc.), single-color, multi-color printing, hot stamping, and silver stamping processes.
- Mirror Coated Art Paper Self-Adhesive Labels
Also known as glassine adhesive paper, mirror-coated art paper self-adhesive labels are high-gloss label papers used for high-end multi-colored product labeling. They can be used for information labels on pharmaceuticals, food, edible oils, alcoholic beverages, beverages, electrical appliances, and cultural goods.
- Kraft Paper Self-Adhesive Labels
Kraft paper inherently has color, which means that color printing will not be very vibrant, but its simple design and textured feel deliver a nostalgic and vintage color performance. Black and white printed kraft paper labels exude a higher sense of sophistication, making them a favorite among handcraft entrepreneurs. Kraft paper self-adhesive labels can be used for wine labels, cultural goods, ethnic style labels, etc. They can also undergo lamination (glossy or matte film) and hot stamping (gold, silver, purple, etc.) processes.
- Aluminum Foil Self-Adhesive Labels
With no paper or film as the support base, these labels are not easily affected by environmental temperature and humidity after pasting. This ensures that the labels do not curl or deform for a long time. They can be used for high-end information labels for pharmaceuticals, food, and cultural goods.
- Fragile Paper Self-Adhesive Labels
The feature of fragile paper self-adhesive labels is that after peeling off the adhesive seal, the label paper immediately breaks and cannot be reused. They are mainly used for anti-counterfeit seals for electrical appliances, mobile phones, pharmaceuticals, food, etc.
- Laid Paper Self-Adhesive Labels
Laid paper self-adhesive labels adhere tightly but are easy to remove, and they are also resistant to high temperatures, melting, and water. They present natural colors, excellent consistency, strong adhesion, and a classic touch. The advantages are the textured feel, retro, simplicity, high-end, and elegant representation. They are mainly used for labels for products such as red wine, tea, cosmetics, etc.
- Thermal Paper Self-Adhesive Labels
Thermal self-adhesive labels are suitable for price tags and other retail information labels.
- Heat Transfer Paper Self-Adhesive Labels
Heat transfer paper self-adhesive labels are suitable for microwave ovens, weighing machines, computer printers to print labels.
- Removable Glue, Washable Glue Self-Adhesive Labels
The face materials of removable glue, washable glue self-adhesive labels include coated paper, mirror coated paper, PE (polyethylene), PP (polypropylene), PET (polyester), etc. They are mainly used for information labels for tableware, household appliances, fruits, etc. After peeling off the adhesive label, no trace is left on the product.
1.2 Applications of Film-Based Self-Adhesive Labels
- PE Self-Adhesive Labels
PE self-adhesive labels have transparent, glossy milky, matte milky face materials, and they have resistance to water, oil, and chemicals. They are commonly used for information labels for bathroom products, cosmetics, and other squeeze packaging.
- PP Self-Adhesive Labels
PP self-adhesive labels have transparent, glossy milky, matte milky face materials. They are resistant to water, oil, and chemicals. They are commonly used for bathroom products and cosmetics and are suitable for heat transfer printing information labels.
- PET (Polypropylene) Self-Adhesive Labels
PET self-adhesive labels have transparent, bright gold, bright silver, matte gold, matte silver, milky, matte milky face materials. They are resistant to high temperature, water, oil, chemical corrosion, and have stronger scratch resistance. They are mainly used for pharmaceuticals, food, alcoholic beverages, cultural goods, etc.
- PVC Self-Adhesive Labels
PVC self-adhesive labels have transparent, glossy milky, matte milky face materials. They are resistant to water, oil, and chemicals. They are mainly used for bathroom products, cosmetics, electrical appliances, hardware, especially suitable for high-temperature product information labels.
- PVC Shrink Film Self-Adhesive Labels
PVC shrink film self-adhesive labels are suitable for exclusive trademark labels for batteries.
- Laser Holographic Film Self-Adhesive Labels
Products adorned with holographic film exhibit a dazzling array of logos, text, and background patterns under white light due to different diffraction angles. This creates a strong visual impact on consumers. Laser holographic film self-adhesive labels possess strong anti-counterfeiting features, are aesthetically pleasing, environmentally friendly, resistant to ink erosion, etc. They are primarily used for packaging of high-end liquor, cosmetics, electronic products, and more.
- Glossy Gold/Silver Self-Adhesive Labels
Glossy gold/silver self-adhesive labels have a special metallic quality and are resistant to water, oil, chemicals, and tearing. They are mainly used for electrical appliances, hardware, mechanical equipment, electronic devices, and more.
- Matte Gold/Silver Self-Adhesive Labels
Matte gold/silver self-adhesive labels are opaque with a metallic texture and have the advantages of being waterproof, oil-resistant, scratch-resistant, and chemically corrosive resistant. They are mainly used for electrical appliances, hardware, machinery, electronic equipment, and more.
2. Procurement, Transportation, and Storage Precautions for Self-Adhesive Stickers
In the production process of self-adhesive products, inspection is an essential step to ensure that the product quality meets standards and customer requirements.
2.1 Appearance Requirements
The surface appearance should be free of obvious dirt, damage, and wrinkles. The printing should be free of color bleed, fading, and other defects. The cutting should be neat, with no significant skew, burrs, or other defects.
The printed content, font, font size, CMYK values, patterns, and positioning should be consistent with the sample. There should be no overprinting, misprinting, missing prints, or obvious streaks.
2.2 Performance Acceptance Tests
The performance acceptance tests for self-adhesive stickers include four aspects: adhesion testing of the printed content, durability of the adhesive performance of the sticker surface, testing of the sticker's layer adhesion, and constant temperature and humidity testing.
- Adhesion testing of the printed content. A cotton cloth soaked with 75% alcohol should be rubbed repeatedly on the printed surface of the sticker with normal pressure for 15 seconds; the printed portion should not peel off.
- Durability of the sticker adhesive performance. After actual assembly, there should be no curling, bubbling, edge rolling, or peeling after being placed at room temperature for seven days.
- Layer adhesion testing of the sticker. Attach the target sticker to a clean, smooth surface, seal a corner with standard transparent tape (packing tape) pressing down firmly, then at a 45-degree angle, quickly tear off the tape. Repeat this operation three times for each corner of the sticker; the target sticker should not show any signs of delamination.
- Constant temperature and humidity testing. The sticker should not fall off or bubble after one hour at -20°C, nor should it fall off or bubble after one hour at 66°C with 95% humidity. When peeled off after testing, there should be no residual adhesive left on the surface.
2.3 Transportation and Storage Requirements
Self-adhesive label materials are made from materials such as paper, plastic, and chemicals, undergoing multiple processes. Improper storage can affect the quality of printing or labeling during use, so storage and usage conditions are more particular.
- Avoid direct sunlight, and protect against dampness, high temperatures, and extremely low temperatures.
- Store separately from flammable and volatile goods; do not mix store.
- Self-adhesive materials should be wrapped in moisture-proof paper or film for storage, and resealed after each use.
- Roll materials should be stored vertically, while flat materials should be neatly stored on pallets or shelves, with the goods at least 10cm above the ground.
- Recommended storage conditions for the warehouse are around 22°C for temperature and approximately 50% for relative humidity.
