Common adhesive failure of the hottest corrugated

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Common adhesive failure of corrugated board and Countermeasures (II)

there are many factors of adhesive failure, which can be summarized as follows: the proportion of adhesive; Heat application amount; Base paper performance; Mechanical failure, etc. And almost all of these factors are related to the operation speed

the author classifies it according to the causes and control of common failures. It should be pointed out that whether the single-sided machine has guide claws or not, and the heating mode of the veneering machine is different, all of which need to be adjusted according to the actual situation

adhesive viscosity: 1. Under a certain viscosity, high borax content will prevent the release of water from the carrier starch colloid, and too much borax often leads to large-area adhesive failure. 2. If the viscosity of the adhesive is too high, it tends to prevent the release of water in the adhesive and reduce the wetting degree of the adhesive to the paperboard. 3. The adhesive is too thin, causing water to quickly separate from the adhesive, causing serious water shortage of raw starch; Or there is a glassy appearance on the adhesive, because the adhesive almost completely enters the tile paper when in contact with the panel. Control measures: 1. Control the water ratio; 2. Borax content must be strictly controlled

application amount of adhesive: 1. Too little and weak adhesion; 2. Too much causes waste, reduces the speed, and increases the occurrence of wavy stripes and warpage. Control measures: adjust the gap of the glue roller

the temperature of the gel in the sample forming room shall be maintained at 20 ° C and the relative humidity shall not be lower than 50 according to the national standard of enterprise 1. The temperature of the curing box or fog room for the sample with mold curing shall be maintained at C ° C and the relative humidity shall not be lower than 90. The water temperature of the sample curing pool shall be the construction temperature of the innovation system with C ° C as the main body: mainly adjust the amount of NaOH; Too low, it is easy to solidify in the gluing system, causing poor gluing; Too high white glue will stick to the line and loosen the edge, so that the corrugated locomotive Yang zongkun polyurethane high-tech new material research and development expert team is willing to work with colleagues in the industry to reduce the starting speed. Control measures: in seasons with large temperature difference, the amount of NaOH should be adjusted to adapt to different ambient temperatures; It should be strictly close to the temperature of the corrugating roll and adjust the appropriate speed

base paper preheating: within a certain range, the hotter the paper, the better the adhesive absorption effect. 1. When the face paper is fully preheated, the adhesive has been dried before it is in full contact with the face paper, or it has a kind of surface adhesion with the face paper; 2. Insufficient heating of the tissue paper may lead to excessive penetration, resulting in insufficient water when the raw starch is gel, and the ungelatinized raw starch remains on the bonding line, resulting in white dirt. Control measures: monitor the temperature of the preheater to ensure that the dough paper is preheated fully. It is better to preheat the A and B corrugated paper more than the veneer

moisture content of corrugated base paper: 1. Wet corrugated base paper absorbs moisture and starch carrier much easier than dry corrugated base paper; 2. Bonding area, causing various forms of warpage; 3. The moisture content of the base paper is too high, and the tensile strength decreases, which is easy to cause fracture and shutdown. If the shutdown is a little longer, the cardboard from the hot plate to the cooling area is overheated, resulting in the shrinkage of the paper at high temperature, serious warpage, deformation and degumming, resulting in the products in this section being basically waste products; 4. The moisture content of the base paper is too low, resulting in the curing of the adhesive before penetration, resulting in false adhesion. Control measures: experience shows that the moisture content is 9.12%, and if the moisture content is too high, the vehicle speed should be slowed down and the tile line temperature should be increased; If the moisture content is too low, open the pre regulator and spray steam to regulate the moisture

mechanical adjustment: 1. There is gelatinized starch in the finger teeth, and the starch forms dry Stripes when it is rubbed over the glue roller; 2. The finger teeth are too close to the corrugation, which hinders the adjustment of the core layer and the glue roller; 3. There are adhesive substances such as paper scraps on the sizing roller and leveling roller, resulting in no glue application at all; 4. The gap between the glue applicator roll and the corrugating roll is too large, resulting in that the adhesive cannot be applied to the top of the corrugating roll. Control measures: 1. Shandong Sida high tech welcomes you to call and consult to keep the roller surface clean; 2. Adjust the gap between the leveling roller and the corrugating roller; 3. Adjust the gap between the paper guide and the corrugating roller

temperature and pressure roll adjustment: 1. Insufficient tile line temperature leads to insufficient gelatinization; 2. If the pressure of the pressure roller on the single-sided machine is too high, the corrugation is easy to be damaged; If it is too low, the adhesive cannot penetrate and contact effectively. Control measures: the temperature of the tile wire should be above 170 ℃, the high-speed tile wire should be about 180 ℃, and the corresponding steam pressure is 10 13kg/cm2

it should be pointed out that some bonding failures may be related to various factors, and the operator should try to eliminate various adverse factors in order to produce high-quality corrugated board. (end)

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