Method for increasing the bearing pressure of corrugated box color box
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At present, most packaging enterprises in China use two kinds of processes to produce color boxes: 1) printing color paper after laminating or glazing, then manually laminating or mechanically fitting corrugated; 2) color graphics It is printed on a plastic film and then covered on a hundred-card paper.
Regardless of the process used to produce the color box, the pressure and compressive strength of the color box are much lower than the ordinary watermarked carton (cardboard line production) of the same material. It is difficult to guarantee the quality when the customer urgently needs or rainy days. Deeply troubled producers, how to solve it?
Everyone knows that the cardboard box production carton is formed by applying glue, heating and bonding, and drying. The color box cardboard of the paste box is not heated and dried, and the moisture in the glue penetrates into the paper. In addition, the surface of the varnish and the plastic film are blocked, and the moisture in the box blank is not released for a long time, and the softness is naturally reduced. So we look for ways to solve the problem from the following factors:
1 paper matching
Some enterprises have such a misunderstanding: the greater the weight of the paper used, the more it can increase the bearing pressure and compressive strength of the carton, but it is not. In order to enhance the bearing pressure and compressive strength of the color box, it is necessary to enhance the pressure bearing capacity of the core paper. As long as the surface paper is not visible after the crepe, the low-gram paper should be used as much as possible; the core paper and the paper paper are preferably used. Straw or wood pulp paper with good strength and high ring pressure. Do not use medium-strength, or strong-strength paper, because it is mostly a mixture of raw pulp and recycled pulp. It has fast water absorption, low ring pressure strength, good toughness but low stiffness. After the test, the water absorption rate of the strong crepe paper is 15%~30% higher than that of the squeegee paper by the Bob method; the paper can increase the gram weight appropriately. Practice has proved that reducing the weight of paper inside, increasing the weight of paper and core paper, whether it is more competitive in terms of quality or price.
2 quality of glue
Most of the carton production currently used is homemade or purchased corn starch glue. The high-quality corn gel not only has good bonding strength, but also enhances the bearing pressure, strength, etc. of the cardboard, and the casing is not easily deformed. The advantages and disadvantages of corn starch glue are closely related to the production process, environment, quality of raw materials and mixing time, etc. It is well known that it is no longer rumored.
The author only refers to the quality requirement of corn starch and the water ratio of starch glue, one of the main raw materials for making rubber. The main point of introduction of the supplementary materials is the reference point: the quality requirement of corn starch, the fineness is 98~100 mesh, and the ash content is not more than 0.1%; Water content 14.0%; acidity 20CC/100g; sulfur dioxide 0.004%; normal odor; color white or slightly yellowish.
If the quality of the rubberized starch does not meet this standard, the water ratio may be appropriately reduced as appropriate. When the temperature rises, the water ratio should be reduced accordingly. Borax and caustic soda should be increased as appropriate, and hydrogen peroxide should be reduced. After the cooked rubber is made, it should not be put for a long time. Especially in summer, it is best to use it. Add 3%~4% of formaldehyde, 0.1% of glycerin and boric acid in the glue, which can increase the water blocking capacity of the paper, speed up the bonding speed, and strengthen the cardboard. hardness.
In addition, environmentally friendly chemical glue, PVA adhesive, can also be used in the sticker board. The utility model is characterized in that the corrugated cardboard is flat, straight and bonded, and is not deformed for a long time. The preparation method is (take 100kg adhesive as an example): the ratio of materials used: polyvinyl alcohol 13.7kg, polyvinyl acetate emulsion 2.74kg, 1.37kg of oxalic acid, and 82kg of water to 1:6). First, the water is heated to 90 ° C, added to the poly-ethylene alcohol to stir evenly, continue to heat to boiling, heat for 3 hours, then add oxalic acid to stir, and finally add acetic acid polyvinyl alcohol emulsion and stir evenly.
3 amount of glue
No matter whether it is manual or automatic mechanical affixing, the amount of glue should not be too large. In actual production, some employees need to increase the amount of glue to avoid degumming. This is not enough and must be strictly controlled. The amount of glue applied should be 80~110g/m2. However, it is advisable to adjust the size of the corrugated material and grasp the amount of glue evenly to coat the peak. As long as it is not degummed, the amount of glue is as small as possible.
4 quality of single-sided cardboard
The quality of single-sided corrugated board is determined by the quality of the base paper, the corrugated type, the working temperature of the corrugating machine, the quality of the adhesive, the speed of the machine, and the skill level of the operator. When the base paper is properly matched and the quality can meet the production requirements, it is necessary to check whether the peak of the corrugating roller of the single-sided machine is seriously worn. The normal 楞 type should be UV type. After a long period of use, the peak of the corrugating roller becomes semi-circular due to the sand content of the paper or the hardness of the corrugating roller itself. The single-sided cardboard is produced in such a condition. The compressive strength is greatly reduced. Also, if the pressure roller is over pressurized, the temperature of the machine is too high, and the single-sided cardboard corrugated is easily broken. Similar single-faced corrugated cardboard has more glue when it is glued to the silicone, and its physical properties change, it is difficult to guarantee the compressive strength.
In the case of normal raw material equipment, it is necessary to adjust the preheating area of the pre-potentiometer appropriately according to the water content of the paper, and control the temperature of one surface to about 200 °C, and adjust the pressure of the pressure level to about 0.3~0.4 kPa (as long as the corrugated paper is not broken). Not cracked, Riva paper fits well).
The speed control of the vehicle speed is low at medium speed, and the viscosity of the adhesive is adjusted to 30~35S. If the adhesive precipitates yellowish water, it should be updated immediately. The operator should be skilled and have a high sense of responsibility. With good professional ethics, the pressure and speed of each roller can be flexibly adjusted according to the actual production conditions, thus ensuring the quality of single-sided corrugated board.
5 production environment
The production environment temperature should not exceed 33 ° C, the air humidity should not exceed 45%, otherwise the cardboard is very easy to absorb moisture, and its own moisture is not volatilized, naturally reducing the pressure of the carton. In addition, the small box blank is preferably rotated for 4 hours before molding. It is indeed necessary for the customer to urgently use the air blower to force the air to promote the bonding of the cardboard as soon as possible to remove excess water.
In short, in order to improve the pressure on the color box of the color box must be comprehensive analysis and consideration, and strive to reduce all kinds of unfavorable factors, can not care about this loss, otherwise all efforts are futile.