Views: 0 Author: Site Editor Publish Time: 2026-04-29 Origin: Site
Throughout the entire production and usage chain of self-adhesive labels, the backing paper (also known as release paper or liner paper) is often regarded as the "behind-the-scenes hero" - although it does not directly appear on the final product's appearance, it determines the success or failure of label printing, die-cutting, waste removal, and even labeling application. Choosing the wrong backing paper can lead to a decrease in production efficiency at best, and even cause a failure in the labeling of the entire batch at worst, resulting in huge losses.
The three main types of base papers currently available on the market - gelatin-based base paper, laminated base paper and PET base paper - each have their own specific application scenarios. This article will comprehensively analyze the underlying logic of these three types of base papers from six dimensions: color, label adhesion, thickness, physical properties, cost and process limitations.
Grasind base paper is made by super-pressurizing the original paper to form a high-density, highly smooth, and dense surface, which is then coated with silicone oil. Its colors mainly consist of white, blue, and yellow. Among them, blue Grasind is the "standard color" in the industry, providing better visual recognition and facilitating operators to quickly distinguish the stripping surface of the base paper.
The stiffness and tensile strength of the Glasind base paper are perfectly balanced. In low-speed automatic labeling scenarios (typically referring to labeling speeds of 30-60 sheets per minute or 20-30 meters per minute), it can smoothly pass through the stripping plate of the labeling machine without wrinkling or breaking due to being too soft, nor causing the labels to fly off due to being too hard. As long as the silicone coating on the base paper is uniform and the label stripping force is stable, problems such as "label dropping" or "label extraction failure" are rarely encountered.
Five gradient options are provided: 40g, 50g, 60g, 70g, and 80g:
40-50g: Suitable for extremely small-sized labels (such as medicine bottles, small samples of cosmetics), requiring extremely thin backing paper to increase the number of rolls per meter and reduce the frequency of roll changes.
60-70g: The most common specification in the industry, covering daily chemical products (shampoo, cleaners), food and beverages, logistics labels, etc.
80g: Suitable for slightly larger or irregularly shaped labels, requiring the backing paper to provide greater die-cutting support.
Ultra-thinness: Under the same roll diameter, Grafix base paper can accommodate 30% to 50% more label length than laminated base paper, significantly reducing the replacement time.
High cost-effectiveness: The production process is mature and the cost of raw materials is controllable. Compared to PET base paper, the cost per unit area can be reduced by 30% to 50%.
Die-cut friendly: The fiber base paper has moderate toughness, long knife mold lifespan, smooth waste removal, and is less prone to breaking.
The biggest drawback of Grasind base paper - its inability to resist curling. Once it is no longer in the rolled form and is cut into single sheets (flat sheets), the base paper will curl severely due to internal stress release, causing the single sheet labels to get stuck on the printing machine (offset printing, screen printing) or have poor paper feeding. Therefore, for any post-processings involving single-sheet printing, manual labeling, or flat sheet die-cutting, Grasind should be abandoned decisively.
The laminated base paper uses ordinary raw paper (kraft paper, white paper, or yellow paper) as the base material. A layer of polyethylene (PE) or polypropylene (PP) film is applied to the surface, and then silicon is coated on the laminated layer. Common colors include white, yellow, and kraft paper color. Among them, the kraft paper laminated base paper is widely used in industrial labels, warehouse signs, etc., emphasizing texture or requiring handwritten labels.
The labels on the laminated base paper are clearly marked as "Not Suitable for Automatic Labeling", and there are two main reasons for this:
Uneven thickness and rigidity: The physical properties of the laminated layer and the base paper differ significantly. During the peeling process, the base paper is prone to irregular deformation, resulting in significant fluctuations in the peeling force, and the sensor of the automatic labeling machine has difficulty in stably tracking.
Layered delamination and blistering: During high-speed peeling or temperature changes, the laminated layer may sometimes separate from the base paper or the original paper, resulting in the scrapping of the entire label.
Therefore, laminated base paper labels are almost exclusively recommended for manual labeling or semi-automatic labeling, such as large warning signs, heavy industrial barrels, and frozen food boxes.
Available in specifications of 70g, 90g, 120g, 140g, 170g, etc. The minimum 70g is already close to the conventional upper limit of Grasins. For large-sized or thick material labels, this thickness actually becomes an advantage - the backing paper can provide strong tear resistance, ensuring that the backing paper will not accidentally tear when manually peeled off.
Thick: The texture is solid, it is not prone to bending or deforming, suitable for large-sized and heavy-duty labels (for example, attaching to plastic buckets that forklifts have carried).
Excellent rigidity: When placed flat or stacked, the labels can remain flat, making them suitable for pre-printing onto single sheets for storage and distribution.
Water-resistant and low-temperature resistant: The laminated layer offers certain moisture-proof properties, and is more stable in cold storage environments compared to Grasini.
Expensive: The lamination process involves an additional step, and the base paper has a higher weight, resulting in a generally higher unit cost compared to similar grades of Glasfiber.
Not suitable for automatic labeling: This severely limits its application in large-scale, high-speed labeling production lines. This implies high labor costs and low efficiency.
PET base paper is a type of polyester film type release film. Its most distinctive feature is total transparency. Through the base paper, one can directly see the adhesive surface and the backside of the substrate. This is very beneficial for visual inspection systems (such as automatic inspection machines), as it enables real-time identification of adhesive bubbles, impurities, or uneven coating.
The dimensional stability of PET base paper is the highest among all base papers. During the operation of high-speed automatic labeling machines (with a speed of 80-120 meters per minute or even higher), PET base paper hardly undergoes stretching deformation, and the peel force is extremely linear. Therefore, for high-speed labeling lines involving pharmaceuticals, vaccine bottles, and high-end cosmetics, almost exclusively PET base paper is used.
Maximum thickness range: 30g, 36g, 50g, 75g, 100g, 150g.
30 - 36g: Suitable for labels on extremely small diameter medicine bottles or syringes, minimizing the roll diameter to the greatest extent.
50 - 75g: The main model for general automated labeling, balancing strength and roll capacity.
100 - 150g: Suitable for ultra-large size electronic tags or special die-cutting processes.
High cost-effectiveness: Perhaps it will come as a surprise - among film-based base papers, the production process of PET base paper is highly mature, and when purchased in large quantities, the unit area cost is even lower than that of some high-end laminated base papers.
Excellent transparency: facilitating quality inspection, visual alignment, and automated sensor detection.
Wide temperature tolerance range: from -20℃ cold storage to 150℃ high-temperature baking (with special formula), far superior to paper-based substrates.
Difficult die-cutting: PET is a film material with high toughness. Ordinary flat-to-flat cutting dies are prone to not cutting through or cutting through the backing paper, resulting in the backing paper being lifted along with the face material when the label is discarded (commonly known as "dropping the backing"). Specialized cutting dies with sharp corners, high-precision round-to-round cutting dies, or an additional backing paper cutting depth control system are required.
High requirements for the smoothness of the adhesive: Due to the extremely smooth and transparent surface of the PET base paper, any unevenness in the adhesive application (such as adhesive lines, bubbles, or missing adhesive) will be magnified infinitely, affecting the appearance of the finished product. Therefore, only a high-precision coating line can ensure the stable production of non-drying PET base paper adhesive.
Indicator Grassin Base Paper Coated Base Paper PET Base Paper
Color White, Blue, Yellow White, Yellow, Kraft Transparent
Suitable Labeling Method Low-speed Automatic Labeling Manual Labeling High-speed Automatic Labeling
Thickness Range (g) 40-80 70-170 30-150
Thickness Sensation Thin Thick Can be extremely thin or extremely thick
Cost Low Higher Medium
Die-cutting Difficulty Easy Easy Difficult
Single Sheet Process Adaptability Not Suitable Suitable Suitable (Requires Anti-static Measures)
Visual Inspection Friendliness Opaque Opaque Extremely Good
V. Selection Decision Tree: One Picture to Determine Which Type of Base Paper to Choose
Manual labeling → Laminated base paper (If cost is a concern and the label is not large, you can also consider Grasins single-sided printing, but the risk is high)
Automatic labeling → Proceed to the next step
Low speed (< 30 meters per minute) → In most scenarios, Graisin base paper is sufficient.
Medium-high speed (> 50 meters per minute) or extremely high stability requirements → PET base paper
For single-sheet offset printing, screen printing, and flat-to-flat single-sheet die-cutting → Avoid using gelatin, choose laminated film or PET instead
Roll-to-roll production → All three are possible
It is → The PET base paper is the best.
This is generally correct for paper-based base papers (grazing, laminated). However, for PET base papers, a 30g PET has an tensile strength that exceeds that of 80g grazing. Thickness does not equal strength.
For a small usage volume, it is more expensive; however, for high-speed labeling lines, due to the reduced downtime for changing rolls and the decreased labeling waste caused by the use of PET base paper, the overall cost is actually lower.
Just the difference in color does not affect performance. Blue was first popularized by a certain international giant as the "default color", not due to any technical advantage.
The selection of self-adhesive backing paper is essentially a "speed, cost, and process compatibility" triangular game.
Glasind Tape: Roll packaging, low-speed automatic labeling, the ideal choice for controlling the number of rolls and costs. Remember its red line - never use it for single-sheet processing.
Laminated base paper: A permanent option for manual labeling, large-sized, thick labels. If you are still using laminated machines for automatic labeling, it's time to reassess your scrap rate.
PET base paper: The future trend of high-speed automatic labeling. The advantages brought by transparency in quality inspection are irreplaceable. As long as your die-cutting accuracy can keep up, PET is often the most convenient and long-term choice.
