At present, most packaging companies in China use two kinds of processes for production of color boxes: (1) First to print colored paper, followed by laminating or glazing, and then manually gluing or mechanically automatically applying corrugating; (2) The color image is printed on a plastic film, covered with a hundred card paper, and then molded. Regardless of the technology used to produce the color box color box, its bearing pressure and compressive strength are much lower than the ordinary watermark carton (paperboard line production) of the same material, it is difficult to guarantee the quality of the customer's urgent need or rainy days, this problem Deeply troubled producers, how to solve it?
Everyone knows that cardboard cartons are produced by gluing, heating and bonding, and drying. After molding, color box cartons are dried without heating. The moisture in the glue penetrates into the paper. In addition to the blockage of the glossy oil and plastic film on the color surface, the moisture in the box blank cannot be distributed for a long time, and the strength is naturally reduced by softening. Therefore, we look for solutions to the problem from the following factors:
1. Paper Matching Some companies have such a misunderstanding: The greater the grammage of the paper inside, the more it can increase the bearing pressure and compressive strength of the carton. This is not the case. To increase the bearing pressure and compressive strength of the color box color box, it is necessary to enhance the core paper's pressure bearing capacity. As long as no visible traces of corrugating are found after the face paper is applied, low weight paper should be used; core paper and tile paper are best used. Grass pulp or wood pulp paper with good strength and high crush strength. Do not use medium-strength or strong-strength corrugated paper, because it is mostly a mixture of raw pulp and recycled pulp. It has fast water absorption, low ring pressure strength, and good toughness but low stiffness. After testing, the water absorbency of medium-strength serigraphy sizing paper is about 15%-30% higher than that of the medium-strength kraft paper; the gram weight can be appropriately increased in the paper. Practice has proved that reducing the weight of the paper inside and increasing the weight of the kraft paper and the core paper is a competitive advantage in terms of quality and price.
2. Quality of glue Most of the carton production now used is homemade or purchased corn starch glue. High-quality corn glue not only has good adhesive strength, but also enhances the cardboard's bearing pressure, strength, etc., and the box is not easily deformed. Advantages and disadvantages of corn starch glue are closely related to the production process, environment, raw material quality, and mixing time. Corn starch quality requirements, fineness of 98-100 mesh, ash content of not more than 0.1%; moisture content of 14.0%; acidity 20CC/100g; sulfur dioxide 0.004%; odor normal; color white or slightly yellowish.
If the quality of gelatinized starch does not meet this standard, the water ratio may be appropriately reduced depending on the situation. As the temperature rises, the water ratio should be reduced accordingly. Borax and caustic soda should be increased as appropriate. Hydrogen peroxide should be reduced in dosage. After the cooked rubber is prepared, it should not be put for a long time, especially in the summer, it is best to use with the use of formaldehyde. Add 3%-4% of formaldehyde, 0.1% of glycerin, and boric acid, which can increase the water resistance of the paper, speed up the bonding speed, and strengthen the cardboard. hardness.
In addition, in the (Article Source: China Wine News, China Wine News Network) 裱 sticker board can also use environmentally friendly chemical glue, the PVA adhesive. Its characteristic is that the corrugated corrugated cardboard is smooth, straight, adhesive, and durable without deformation. Its production method is (100kg of adhesive as an example): the ratio of materials used: polyvinyl alcohol 13.7kg, polyvinyl acetate emulsion of acetic acid 2.74kg, 1.37kg oxalic acid, 82kg water, 1:6 water ratio. First of all, the water is heated to 90° C., and the polyethylen burnt alcohol is added into the mixture. The mixture is heated until the water boils, and the temperature is maintained for 3 hours. Then, oxalic acid is added for stirring, and then the acetic acid polyvinyl alcohol emulsion is added and the mixture is evenly mixed.
3. The amount of glue No matter whether it is manual or automatic machinery, it should not be too large. In actual production, some employees have to take strict control in order to avoid degumming. The amount of glue should be 80-110g/m2. However, depending on the size of the corrugator, it is advisable to control the amount of rubber evenly to coat the peak, as long as it does not degumming, the smaller the amount of glue, the better.
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 running speed of the machine, and the technical level of the operator.
When the base paper with a reasonable and quality can meet the production needs, it is necessary to check whether the single-sided machine corrugated roller peak wear. The normal enamel type should be UV type. After a long period of use, the peak of the corrugating roll will become a semicircle due to factors such as the sand content of the paper or the hardness of the corrugating roll itself. The compressive strength is greatly reduced. In addition, if the pressure roller is over-pressurized, the temperature of the tamper machine is too high, and the single-sided cardboard corrugated board is easily broken. When similar single-sided corrugated cardboard is used to glue, it is difficult to ensure the compressive strength.
In the case of normal raw material equipment, depending on the water content of the paper, the preheater preheater area should be appropriately adjusted, the single-sided temperature should be controlled at about 200°C, and the pressure magnitude pressure should be adjusted to about 0.3-0.4kPa (as long as the corrugated paper is not broken). No cracking, good Riva paper fit).
The speed of the vehicle is controlled at the medium speed of the equipment design speed is low, and the viscosity of the adhesive is adjusted to 30-35S. If the adhesive precipitates yellowish water with odor, it should be updated immediately. The operator must be skilled and highly responsible. With good professional ethics, the pressure and speed of each roller can be flexibly adjusted according to actual production conditions, so that the quality of single-sided corrugated cardboard can be guaranteed.
5. Production environment The temperature of the production environment should not exceed 33°C, and the air humidity should not exceed 45%. Otherwise, the cardboard can easily absorb moisture, and its moisture is not volatilized, which naturally reduces the bearing pressure of the carton. In addition, it is better to mold the small box blank after rotating for 4 hours. Due to the urgent needs of customers, fans can be forced to blow air to promote the adhesion of the cardboard as soon as possible and to drive off excess moisture.
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