From material selection to printing to finished products, explain the whole process of shrink film sleeve label production

From material selection to printing to finished products, explain the whole process of shrink film sleeve label production

Shrink-sleeve labels are becoming more and more popular in the market due to their combination of high-quality graphics and distinctive shapes. What are the characteristics, advantages, design principles and production points of shrink film labels?

Concept and Advantages

Shrink film sleeve label is a film sleeve label printed on plastic film or plastic tube. It has the following characteristics:

1. The shrink film sleeve label is easy to process, the packaging is sealed, anti-pollution, and has good protection for goods;

2. The film sleeve is close to the product, the packaging is compact, and the product shape can be displayed, so it is suitable for irregular products that are difficult to package;

3. When labeling the shrink film sleeve label, no adhesive is required, and the same transparency as glass can be obtained;

4. The shrink film sleeve label can provide 360° all-round decoration to the packaging container, and can print product information such as product descriptions on the label, so that consumers can understand the performance of the product without opening the package;

5. The printing of the shrink film sleeve label belongs to the inner printing of the film (the picture and text are on the inside of the film sleeve), which can protect the imprint, and the label has better wear resistance.

Design points and material selection principles

1. Label design

The design of the decorative pattern on the film sleeve should be determined according to the thickness of the film. When designing a pattern, first of all, it is necessary to find out the horizontal and vertical shrinkage rates of the film, as well as the allowable shrinkage rate in each direction after packaging and the allowable deformation error of the decorative pattern after shrinking, so as to ensure that the shrinked pattern and text can be accurately restored.

2. Film thickness and shrinkage

The materials used for shrink film sleeve labels should focus on three factors: environmental protection requirements, film thickness and shrinkage performance.

The basis for determining the film thickness is the application field of the label and the cost factor. Of course, price is not a decisive factor, because each film has its own uniqueness, and users and trademark printers must identify the film used and the process most suitable for the material before signing the contract. In addition, the indicators required by the processing equipment and other process factors also directly affect the choice of thickness. Generally, the thickness of the film required to make the shrink film sleeve label is 30 to 70 μm, among which, the films of 40 μm and 50 μm are used more. In addition, there are certain requirements for the shrinkage rate of the film, and the transverse (TD) shrinkage rate is higher than the longitudinal (MD) shrinkage rate. The transverse shrinkage rates of commonly used materials are 50% to 52% and 60% to 62%, and can reach 90% in special cases. The longitudinal shrinkage rate is required to be 6% to 8%. When making shrink film sleeve labels, materials with a small longitudinal shrinkage rate should be selected as much as possible.

Film material

The materials for making shrink film sleeve labels are mainly PVC (polyvinyl chloride) film, PET (polyester) film, PETG (modified polyester) film, OPS (oriented polystyrene) film, etc. Its performance is as follows:

1. PVC film

PVC film is currently the most widely used film material. It is low in price, has a large temperature shrinkage range, and does not require high heat sources. The main processing heat sources are hot air, infrared rays or a combination of the two. However, PVC is difficult to recycle, and it produces toxic gas when burned, which is not conducive to environmental protection. It has been banned in Europe and Japan.

2. OPS film

As a substitute for PVC film, OPS film is increasingly widely used. It has good shrinkage performance and is also environmentally friendly. The domestic market of this product is in short supply. At present, high-quality OPS mainly relies on imports, which has become an important factor restricting its development.

3. PETG film

PETG copolymer film is not only conducive to environmental protection, but also can adjust the shrinkage rate in advance. However, due to the excessive shrinkage, it is also limited in use.

4. PET film

PET film is an internationally recognized environmentally friendly heat shrinkable film material. Its technical indicators, physical properties, application scope and usage methods are all close to PVC heat shrinkable film, but the price is cheaper than PETG, and it is the most advanced one-way shrinkable film at present. Its transverse shrinkage rate is 70%, and its longitudinal shrinkage rate is less than 3%, and it is non-toxic and non-polluting. It is the most ideal material to replace PVC.

In addition, the heat-shrinkable film tube is also a material for the production of shrinkable film sleeve labels, and can be formed at one time without sewing in production. Compared with laterally flattened film, the cost of producing shrink sleeve labels with heat shrinkable film tubes is lower, but the surface printing of the tube body is more difficult to achieve. At the same time, the graphics and texts of the heat-shrinkable film tube labels can only be printed on the surface of the film, and the graphics and texts are easily worn during transportation and storage, thus affecting the packaging effect.

Shrink film sleeve label printing

1. Printing

Printing on selected films. At present, the printing of shrink film sleeves mainly adopts gravure printing, using solvent-based inks, followed by flexographic printing. With the development of flexo printing technology, the printing color is bright and clear, which is comparable to gravure printing, and has the thick and high gloss of gravure printing. In addition, flexo printing mostly uses water-based inks, which is more environmentally friendly.

2. Slitting

Use a high-performance slitting machine to slit the printed roll film material longitudinally, and at the same time process the edge of the film to make it smooth, flat and not curled. When using the slitting machine, care should be taken to avoid heating the blade, because the heated blade will cause the part of the film to be wrinkled.

3. Suture

The slitted film is centrally sewed with a sewing machine, and the nozzles are glued to form a film sleeve required for packaging. The material allowance required for suture depends on the suture accuracy and the skill of the operator. The maximum allowable amount of suture is 10mm, usually 6mm.

4. Horizontal cutting

Pack the film sleeve on the outside of the product, and use a slitting machine to cut it horizontally according to its packaging size. When the shrink film is heated at an appropriate temperature, its length and width will shrink sharply (15% to 60%). Generally, the size of the film is required to be about 10% larger than the maximum size of the product.

5. Heat shrinkage

Heated by hot tunnel, hot oven or hot air gun. At this time, the shrink label will quickly shrink along the outer contour of the container and closely fit the outer contour of the container to form a label protective layer that is completely consistent with the outer contour of the container.

In the production process of shrink film sleeve labels, each process must be strictly inspected by a special inspection machine to ensure production accuracy.

Scope of application

Shrink labels are highly adaptable and can be used for surface decoration and decoration of packaging containers such as wood, paper, metal, glass, and ceramics. They are widely used in the packaging and decoration of food, daily chemical products, and chemical products, such as various beverages and cosmetics , children's food, coffee, etc. In the field of pharmaceutical labels, paper is still the main substrate, but the development of film packaging has been increasing rapidly. At present, the key to the development of shrink film sleeve labels is to reduce costs, and only in this way can we improve competitiveness and gain a larger market share.