一、 The characteristics of the oil drum industry and the labeling requirements

1. The characteristics of the oil drum

The main component of the oil drum is PE, which will add color masterbatch and additives in different proportions according to the color or other requirements during the production process. The oil barrel is blow-molded, and the temperature is very high when it comes out of the mold. It takes 24 to 48 hours to completely cool down, stabilize the size, and release small molecular substances in the barrel.

The surface of the oil drum is relatively rough due to the requirement of demolding, and the surface energy is relatively low. PE material has a large thermal expansion coefficient, and the size of the barrel changes greatly when the temperature difference is relatively large across the country.

2. The labeling process of the oil drum

The barrel is produced and placed in a breathable plastic bag for 48 hours (cooling, shaping, release) ---- machine or manual labeling ---- placed above the minimum labeling temperature for 24 hours (glue viscosity play) ---- Inspection delivery

3. Requirements for labels

1) Low surface energy and rough surface-----high-viscosity thickened glue

2) The expansion of the barrel body after filling brings the demand for resistance to friction-----abrasion resistance varnish or coating

3) Different printing appearance effects-a variety of surface materials are available

4) PE material has a large thermal expansion coefficient-it is best to choose PE surface material to adapt to the huge temperature difference across the country

 

二、 Introduction to the application of oil barrel label and common failure modes

1. Introduction

At present, there are many kinds of oil drum labels on the market, and the application is complicated. The summary is as follows:

2. Surface material: coated paper, mirror coated paper, synthetic paper, white PE, bright silver PE, etc.

3. Glue: thickened high-viscosity glue.

4. Label surface treatment method: glazing oil, glazing film.

5. Labeling method: machine labeling, manual labeling.

6. Labeling process: most of them are completed by the bottle factory and then sent to the filling factory, and a small number of online labeling and canning operations.

7. Type of failure: label curling or falling off; label curling or bell mouth; label blistering

 

三、 Methods to avoid these three types of label failure

1. The labeling is upturned

The stickiness of the glue is the guarantee of perfect labeling, but there are other factors if we do not pay attention to it, there will also be a risk of warping:

2. Temperature problem

Winter is a period of high occurrence of oil drum label warping. We should prevent it from the following aspects:

1) The label should be stored in an environment above the minimum labeling temperature, or the label should be placed in the environment 24 hours before labeling to warm up to ensure the activity of the glue;

2) Ensure that the temperature of the barrel is above the minimum labeling temperature;

3) The barrel is placed above the minimum labeling temperature within 24 hours after labeling to ensure that the glue viscosity continues to reach the maximum level. In the examples, there have been many cases in which the labels were moved to an outdoor or cold warehouse immediately after the label was put on in winter, or the labels were lifted or even fell off due to direct shipment.

Tips: Install a heating lamp on the labeling machine to increase the temperature of the label before labeling, which can increase the viscosity of the glue and improve the labeling effect. The labeling factory can adjust the heat preservation time after labeling according to the actual test results, subject to no warping.

3. Humidity issues

The humidity problem is often overlooked by everyone, but occasionally such problems occur.

1) When the humidity is high in the rainy season, a water film may be formed on the surface of the barrel, and the viscosity of the glue when the label is attached to the water film will decrease, which will cause the label to warp;

2) Unfinished rolls may be produced during labeling. After being returned to the warehouse, they are not packaged in waterproof bags. Exposure to the air will cause the water in the glue to volatilize, and the glue will become weak, or even become dry glue, completely losing its viscosity.

Tips: The labeling factory can prepare some ziplock bags for packaging the opened label rolls.

4. Surface energy of the barrel

Additives may be added during the production of barrels due to various reasons, some of which will precipitate out of the barrel, causing the barrel surface to be oily and low in surface energy; in addition, the surface of the mold cavity of the production barrel will also accumulate some substances after long-term use. As a result, the surface energy of the barrel is reduced, which affects the labeling effect. It is recommended that the surface energy of the barrel should be above 34 dyne.

Tips: The barrel body can be flame treated to increase the surface energy before labeling

5. The pressure of petting bidders

Self-adhesive is also called pressure-sensitive adhesive. Only under proper pressure can the viscosity of the glue be brought into play.

1) Manual labeling: Compared with the stability of large-scale machine production, the manual labeling actions of personnel may be affected by factors such as physical condition, working hours, and operational proficiency, and the labeling quality is not so stable. The label may be lifted due to insufficient pressure to touch the label.

2) Machine labeling: The marking device is the key. The brushes, sponge wheels and other devices on the market are not advisable. It is recommended to use an appropriately flexible marking plate and hold it with the upper and lower arms.

6. Label flatness problem:

1) When the label is covered with a film, if the tension of the film is too large, the film will shrink after die cutting, which will drive the label to curl upwards and warp after labeling;

2) When the film is covered on paper materials, the PP film may shrink due to the low temperature of the labeling environment;

3) It is not recommended to use hot film, the temperature is about 90 degrees when laminating, and the shrinkage is severe when it cools down.

4) The label with varnish may have curled edges due to ink shrinkage.

Tips: The shrinkage of the film is unidirectional, and the shrinkage of the ink is omnidirectional. The printing factory should check the flatness of the label in time when die-cutting. The film-coated label is preferably rolled down slightly.