Comparison of synthetic paper and coated paper

I. Material Nature and Basic Characteristics

The synthetic paper is made from plastic resins such as polypropylene (PP) and polyethylene (PE), and is formed into a film with the texture of paper through extrusion technology. Its core advantages lie in complete waterproofing, anti-tear resistance (the transverse tear strength is 3-5 times higher than that of coated paper), and chemical corrosion resistance. Moreover, the production process does not require cutting down trees and can be 100% recycled. However, due to the non-degradable nature of the plastic components, the long-term environmental impact remains controversial.

Coated paper is based on wood pulp and is coated with kaolin and other coatings. It undergoes super calendering treatment to form a smooth surface. Its whiteness can reach over 90%, and it has excellent ink absorption properties, capable of achieving a fine printing effect of over 1200dpi. However, its water resistance is weak, and it is prone to curling when the humidity exceeds 60%.

II. Key Performance Comparison

Physical Durability

Synthetic paper: It remains stable within the temperature range of -20℃ to 80℃. It passes ISTA 3E maritime simulation tests and has a compressive strength 60% higher than that of coated paper. When used outdoors, nano-coated synthetic paper can resist yellowing caused by ultraviolet rays and has a lifespan of over 5 years.

Coated paper: It is prone to ink diffusion in humid environments. For example, as shown in the case of beer labels, uncoated coated paper curls at the edges within 24 hours in refrigerated conditions. Sharp blades are required for die-cutting, otherwise, fiber tearing may occur.

Printing Adaptability

Synthetic paper: It requires an alcohol wetting system (with a concentration of 13% ± 2% alcohol) to reduce surface tension. Fine particle powder (with a particle size of < 50μm) is recommended to prevent sticking pages. The adhesion of UV ink can reach grade 4B (scratch test), but solvent-based ink requires pre-coating of a base glue.

Coated paper: Conventional offset printing and flexographic printing can achieve high glossiness. Mirror-coated coated paper can have a glossiness of over 75° (measured at 60° angle), suitable for scenarios with high visual requirements such as cosmetic labels.

Processing Technology

Synthetic paper: It can undergo further processing such as embossing and hot stamping. The die-cutting accuracy error is less than ±0.1mm, but attention should be paid to the material orientation (the difference in tear strength in the silk direction can reach 20%).

Coated paper: The die-cutting pressure needs to be controlled at 1.2-1.5 tons / square centimeter. Otherwise, edge burrs may occur. Tension control (3-5N/m) is required for roll materials to avoid wrinkling.

III. Application Scenarios Segmentation

Typical Applications of Synthetic Paper

Industrial Field: Automotive component logistics display boards use nano synthetic paper, which maintains label integrity in oil-contaminated environments, with a 80% reduction in failure rate compared to coated paper.

Outdoor Signage: High-temperature resistant synthetic paper is used for highway signs, with a color difference value ΔE < 3 after 5 years, while similar products of coated paper have a ΔE > 5 after 1 year.

Food Packaging: Freezing food labels use low-temperature resistant synthetic paper (-50℃ applicable), solving the brittleness problem of coated paper in freezing environments.

Core Scenarios of Coated Paper

High-end Packaging: Cosmetics labels use mirror-coated coated paper, combined with local UV glossing process, to achieve a metallic texture effect, with a cost 30% lower than the synthetic paper solution.

Document Management: Medical file labels use fluorescent-free coated paper, meeting ISO 10993 biocompatibility standards, while synthetic paper requires additional toxicological testing.

Short-term Promotion: Supermarket price tags use 80g coated paper, with a printing cost of only 60% of synthetic paper, and can be quickly degraded to meet green retail requirements.

IV. Cost and Environmental Balance

Direct Cost

The unit price of standard weight (80g) coated paper labels is approximately 0.8-1.2 yuan / A4, while that of synthetic paper is 1.5-2.5 yuan / A4. However, synthetic paper can reduce the frequency of replacement by 3-4 times in outdoor applications, resulting in significant long-term cost advantages. For bulk purchases, the price for coated paper can be reduced to 0.5 yuan per A4 sheet when ordering 100,000 sheets or more. However, for synthetic paper, due to its complex production process, the price remains at 1.3 yuan per A4 sheet when ordering 10,000 sheets or more.

Environmental Impact

Synthetic Paper: The production energy consumption is 15% lower than that of coated paper, but the CO₂ emissions during incineration are 20% higher than those of coated paper. The EU's "Single-Use Plastic Directive" has included synthetic paper labels in the recyclable category, but they need to be sorted separately.

Coated Paper: Products made from FSC-certified wood pulp can reduce carbon emissions by 0.8 tons per ton, but the production process requires 300 tons of water per ton of paper.

V. Technological Development Trends

Synthetic Paper Innovation:

Biobased synthetic paper (such as PLA-based substrate) has achieved mass production, with a degradation cycle shortened to 180 days, but the cost is 40% higher than that of traditional synthetic paper.

Self-repairing synthetic paper uses microcapsule technology to automatically repair surface scratches and has emerged in the field of electronic device labels.

Coated Paper Upgrade:

Nano-coated coated paper maintains printing performance while increasing water resistance to IPX4 level and has been used in smart home product labels.

Edible ink coated paper (certified by FDA) provides a new option for food packaging, but the shelf life is limited to 6 months.