Manufacturing technology and product characteristics of PVC heat shrinkable film

Heat shrinkable film is mainly made by mixing and extruding several different brands of poly (vinyl chloride) resins, which has the properties of puncture resistance and good quality. The goods stacked on pallets are wrapped and packed, which makes the packages stable and tidy, and is not afraid of water. It is widely used in foreign trade import and export, paper making, hardware, plastic chemical industry, building materials and food industry.

In addition, heat shrinkable film's main uses: this packaging material can be used not only in the food industry, but also in the packaging of wine, sporting goods, stationery, video products and handicrafts. Not only that, the application of this kind of packaging material is common in our life, and it is almost always used in packaging. What is important is that you can color print various patterns and make shrink labels, which can mark the products and enhance the aesthetics of the products. By virtue of the high shrinkage, it can solve the problem that many special-shaped products can't use ordinary stickers. heat shrinkable film as a label by thermal transfer is a good film packaging material.

The outstanding feature of heat shrinkable film is the phenomenon of contraction and recovery. That is, when the heat shrinkable film is created, the heating well is stretched in the corresponding direction, and then the inkstone is cooled, so that the chain molecules are arranged in the stretching direction. When the film is reheated to the quietness during stretching, the chain molecules return to the original disordered state, and the thin size also returns to the size before stretching, that is, the phenomenon of shrinking X is produced. The heat shrinkable label is mainly gravure printing, and the printed graphics and texts are bright in color and good in saturation. Because it can decorate the packaging container closely, it can highlight the appearance of the goods and enhance the appearance decoration of the goods, which can produce a good shelf effect. In the process of labeling, the label and container can be integrated without using adhesive, which can realize the large-scale on-line operation of goods and reduce the production cost.

Preparation technology of PVC heat shrinkable film;

1. Production Principle The stable state of polymer chain tends to curl. When the polymer is in a high elastic state when heated and melted, the orientation of the polymer chain is stretched and straightened under the action of external force, and the orientation state of the polymer chain is frozen after rapid cooling reaches the glass transition temperature. When the temperature rises again, the polymer chain tends to be stable and curls, which is macroscopically manifested as contraction. According to its shrinkage principle, there is no chemical change, so it is called "physical reducibility". Using the above principle, the PVC heat shrinkable film made by blow molding is made after twice inflation and rapid cooling.

2. The conical twin-screw extruder is selected as the basic technological condition of granulation. The main equipment parameters are as follows: the screw diameter is 80/143 mm; Screw length 1800mm；; The rotation direction is measured outwards; The screw speed is 3.7-37r/min; The extrusion amount is 300 kg/h; The driving power is 60kw.

3. The practice of material mixing shows that the material mixing sequence has great influence on the product performance, and the following mixing sequence is beneficial to the improvement of product quality. PVC+ lubricant (mixed at low speed at normal temperature), liquid additive (mixed at 80℃), MBS and ACR (mixed at 120℃), cold mixed to 40℃ and discharged.

Heat shrinkable film's product features:

1. heat shrinkable film has a good transparency and a light transmittance of 80%, which can display products and publicize them invisibly, thus reducing the distribution faults in the logistics link.

2. heat shrinkable film has good flexibility, is not easy to be damaged, has strong explosion resistance, strong impact resistance, strong tear resistance and strong tensile force, and can replace box packaging.

3. heat shrinkable film is a clean, odorless and clean packaging material.

4. heat shrinkable film has a large shrinkage rate, which can tightly wrap articles after thermal shrinkage. If the PE straight-through bag (with openings at both ends of the bag) is made after thermal shrinkage, the articles can be lifted at both ends of the opening, which can accept the weight of 15KG and is convenient to carry.

5, heat shrinkable film, not afraid of water and dust, can not only achieve the packaging function, but also beautiful products and maintenance products.

PVC is easy to break when printed in heat shrinkable film. It is not that the quality of PVC shrink film is poor, but that there is a solvent in the printing ink used for PVC that will dissolve the PVC film, and the volatility of this solvent is small. Therefore, if there is too much solvent in the solvent used for PVC ink, the PVC shrink film will dissolve and be broken during printing. However, if the printing ink for PVC is not used, the printing fastness is not good.