Affected by subjective and objective factors, self-adhesive labels in the labeling process often appear label warping, wrinkles, blisters, backing paper breaks and other problems, customer complaints, so that the label printing enterprises headache. Among them, warping is the most common in the labeling process. Today, let's take a look at the other five causes of label warping.
1. Labeling surface state on the impact of labeling warpage
The roughness of the labeling surface has a great impact on the labeling effect. The rougher the labeling surface, the more likely to appear labeling warpage bad problem. In addition, if the labeling surface has impurities such as oil, water droplets, dust, etc., it is equivalent to pasting glue on these impurities instead of pasting on the labeling surface, and it is also easy to appear labeling warpage.
In addition, whether the surface of the labeled object after special treatment may also affect the final labeling effect. For example, when filling small-diameter glass bottles, the surface of the bottles will be cleaned with silicone water in advance, as it is not allowed to hang the potion on the wall. After cleaning, if there is more silicon residue, the label will warp after labeling.
2. Labeling environment will also lead to labeling warpage
In general, the labeling temperature requirements generally include labeling temperature, labeling temperature, labeling environment temperature, labeling after 24h storage temperature has four aspects, the details are as follows:
1) Each self-adhesive labeling material technical parameters clearly marked the minimum labeling temperature and the use of temperature range.
2) labeling, the ambient temperature must comply with the minimum labeling temperature of the label, only then, in order to make the labeling glue normal flow, play normal degree.
3) The surface temperature of the pasted material must be higher than the minimum paste standard temperature, so that originally has the fluidity of the glue in the paste to the low temperature surface will not deteriorate or stop flowing, resulting in viscosity reduction.
4) The ambient temperature after labeling is also important. In order to maintain the fluidity of the adhesive, it is necessary to convert the labeled adhesive from initial viscosity to final viscosity in an environment above the minimum labeling temperature.
3. The effect of the shape of the labeled object on label warpage
In order to achieve the desired labeling effect, the labeling surface of the labeled object should become a flat surface after unfolding. If the label surface is curved in both directions after unfolding (spherical label surface), it is difficult to achieve the desired labeling effect. Therefore, the bottle design should try to avoid such a shape, or try to avoid such a position.
In addition, due to production cost pressures, blow molding factories often reduce the gram weight of the bottle to make the bottle thinner, resulting in greater deformation of the bottle before and after filling, unable to apply greater labeling pressure, such as labeling after hot filling 30 ~ 40 ℃ liquids, the bottle part of the bottle will be raised and deformed, and the bottle will be retracted after cooling, resulting in labeling warping of the undesirable phenomenon.
4. Labeling equipment on the impact of labeling warpage
For different labeling surfaces and labeling requirements, different labeling mechanisms should be selected, such as sponge wheels, pulleys, labeling boards and so on. Labeling machine should be labeled with the appropriate labeling pressure to ensure that the label and labeling machine perfect fit.
When the labeling pressure is insufficient, such as using soft brushes, labeling plates that are too soft, sponge wheels, pulleys that are too widely spaced from the bottle, etc., the label will warp due to insufficient labeling pressure. In addition, if the tender mechanism is aging, it will affect the tender pressure, which may lead to labeling problems.
5. The effect of labeling process on labeling warpage
Different labeling processes can also affect labeling warpage. An ice cream brand, in the ambient temperature of 10 ℃ to ice cream plastic box filled with ice cream, automatic lid, and then in the box lid and box around the automatic labeling, and finally in the -15 ℃ ambient temperature in the quick-freeze molding, 1 ~ 2h into a large-scale cold storage, found that most of the label in the quick-frozen warped, transferred to a large-scale cold storage, most of the labels fall off.
The above are a few of the regular labeling warping reasons we routinely encountered, pls follow us Sinopack Industry the next issue we share a few other reasons!