Guide to Buy Kraft Paper in Haimu

1.  Printing Issues

Problems:

● Poor ink absorption, leading to slow drying and smudging.

● Uneven color distribution and blurry images.

● Poor ink adhesion, especially with UV printing.

Solutions:

✅ Use fast-drying inks or UV-curable inks and adjust printing pressure accordingly.

✅ Opt for low-viscosity inks to improve print uniformity.

✅ Perform surface treatments such as corona treatment or priming to enhance ink adhesion.

2.  Die-Cutting and Waste Removal Issues

Problems:

● Cast coated paper is brittle, making it prone to cracking or chipping during die-cutting.

● Difficult waste removal, reducing production efficiency.

● Uneven cutting edges, leading to labels peeling off or rough edges.

Solutions:

✅ Use sharp die-cutting blades to improve precision and minimize edge cracking.

✅ Adjust die-cutting pressure to prevent paper breakage.

✅ Modify the waste removal process by widening waste edges or optimizing the cutting layout.

3.  Adhesion Problems

Problems:

● The glossy surface makes it difficult for adhesives to bond properly.

● Labels may curl or lose adhesion over time.

● Adhesive performance weakens in cold or humid environments.

Solutions:

✅ Choose high-tack adhesives specifically designed for cast coated paper.

✅ Ensure labels are fully dry before storage to prevent adhesive degradation.

✅ Use suitable release liners (e.g., glassine or PET) to prevent curling.

4.  Water and Abrasion Resistance

Problems:

● Exposure to moisture can cause bubbling or coating detachment.

● Labels are prone to scratching or wear over time.

Solutions:

✅ Select waterproof cast coated paper or apply an additional water-resistant coating.

✅ Use scratch-resistant coatings or lamination to enhance durability.

✅ Apply UV varnish for extra abrasion resistance.

5.  Warping Due to Temperature and Humidity Changes

Problems:

● Paper deforms when exposed to moisture, affecting label application.

● High temperatures can soften the coating, reducing adhesion quality.

Solutions:

✅ Store in a controlled environment (recommended: 20-25°C, 40-60% humidity).

✅ Avoid prolonged exposure to heat or humidity during transport.

✅ Use thicker or composite materials for better stability.

6.  Environmental and Regulatory Compliance

Problems:

● Some coatings may not comply with environmental regulations, affecting exports.

● Cast coated paper is less recyclable, increasing sustainability concerns.

Solutions:

✅ Choose materials that meet ROHS, REACH, or other regulatory requirements.

✅ Use eco-friendly water-based coatings to minimize chemical impact.

✅ Opt for recyclable or biodegradable label materials to align with sustainability goals.

When using metallized paper for label production, several common issues may arise. Below is a list of potential problems and corresponding solutions:

1. Printing Issues

Problems:

● Poor ink adhesion: The smooth metallized surface makes it difficult for regular inks to adhere, leading to ink peeling or blurring.

● Slow drying speed: The metallized layer reduces ink absorption and evaporation, causing longer drying times and lower production efficiency.

● Low color reproduction accuracy: The reflective nature of the metallized surface can affect color presentation, leading to deviations in print color.

Solutions:

✅ Use specialized inks (such as UV or water-based inks) to improve adhesion and drying speed.

✅ Apply corona treatment or pre-coating to increase surface energy and improve ink adhesion.

✅ Use a white base layer or adjust color management settings to compensate for the reflective effect.

2. Coating and Surface Treatment Issues

Problems:

● Poor adhesion of UV varnish or lamination: The low surface energy of the metallized paper may cause coatings or varnish layers to peel off.

● Low surface tension: This can affect ink, coating, and adhesive performance, leading to poor processing results.

Solutions:

✅ Use corona treatment or pre-coating layers to increase surface energy, improving the adhesion of UV varnish, lamination, or top coatings.

✅ Choose specially formulated UV varnish or water-based coatings designed for metallized paper.

✅ Store the paper in a dry environment to prevent moisture from affecting the metallized layer.

3. Die-cutting and Processing Issues

Problems:

● Edge cracking or aluminum layer peeling: The metallized layer may detach during die-cutting, affecting the label’s appearance.

● Aluminum layer separation after cutting: The metallized coating may peel off when the label is bent or folded, reducing product quality.

Solutions:

✅ Use high-quality die-cutting blades and optimize pressure settings to prevent cracking or peeling.

✅ Choose flexible metallized paper to enhance adhesion and resistance to folding.

✅ Adjust the die-cutting angle to minimize direct impact on the metallized layer, reducing peeling risks.

4. Adhesion Issues

Problems:

● Weak adhesive bonding: The metallized layer can interfere with glue adhesion, making labels difficult to stick.

● Bubbles or detachment: Adhesives may form bubbles or fail in high humidity or high-temperature environments.

Solutions:

✅ Use adhesives specifically designed for metallized surfaces, such as high-adhesion solvent-based adhesives.

✅ Apply a primer or coating layer to enhance the adhesive’s bonding ability.

✅ Control humidity levels to prevent moisture absorption, which could impact adhesion performance.

5. Durability and Storage Issues

Problems:

● Moisture absorption and warping: Metallized paper has higher moisture sensitivity, leading to deformation when improperly stored.

● Poor heat resistance: High temperatures may cause oxidation or discoloration of the metallized layer.

Solutions:

✅ Store in a dry and temperature-controlled environment (recommended humidity < 50%, temperature 20-25°C).

✅ Use moisture-proof packaging to prevent humidity damage during storage and transportation.

✅ Avoid direct sunlight and high temperatures to prevent oxidation or discoloration of the metallized layer.

6. Environmental and Regulatory Issues

Problems:

● Difficult to recycle: Some metallized papers are harder to recycle due to the presence of the aluminum layer.

● Food safety concerns: Some metallized coatings may not comply with food packaging regulations.

Solutions:

✅ Choose eco-friendly and recyclable metallized paper, such as water-based coated metallized paper.

✅ Ensure compliance with FDA, EU, and other food safety standards, especially for food packaging labels.

✅ Reduce the use of solvent-based chemicals in production and adopt environmentally friendly coating technologies to lower pollution risks.

Summary Table