1.膠黏劑的制備
危包紙箱的制作離不開(kāi)膠黏劑。合理的配方、較好的黏合強(qiáng)度，是提高危包紙箱抗壓強(qiáng)度基礎(chǔ)的保障。
在低溫低濕的環(huán)境(如冬季)下生產(chǎn)包裝紙箱時(shí)，可適當(dāng)增大水與膠黏劑的比例。其中，生產(chǎn)單瓦楞紙板的膠黏劑的黏度應(yīng)控制在 15s，固含量應(yīng)控制在17%左右;生產(chǎn)三層瓦楞紙板時(shí)，膠黏劑的黏度應(yīng)控制在40s，固含量應(yīng)控制在19%。同時(shí)，硼砂的用量減少至4千克，以促進(jìn)膠黏劑更多地滲透到瓦楞紙板內(nèi)部。
在高溫高濕的環(huán)境(如夏季)下生產(chǎn)包裝紙箱時(shí)，應(yīng)減小水與膠黏劑的比例。其中，生產(chǎn)單瓦楞紙板時(shí)，膠黏劑的黏度應(yīng)控制在 18s，固含量應(yīng)控制在1 8%左右;生產(chǎn)三層瓦楞紙板時(shí)，膠黏劑的黏度應(yīng)控制在55s，固含量應(yīng)控制在2l%。同時(shí)，硼砂的用量增加至6 千克，以增加膠膜硬度，從而減少膠黏劑滲透至瓦楞紙板內(nèi)部，達(dá)到提高包裝紙箱抗壓強(qiáng)度的目的。
2.間隙值
只有上下瓦楞輥與壓力輥之間的間隙值合理，才能保證包裝紙箱的成型效果，不然塌楞等問(wèn)題會(huì)直接降低包裝紙箱的抗壓強(qiáng)度。瓦楞機(jī)操作過(guò)程中，單瓦楞紙板涂膠間隙值、三層瓦楞紙板涂膠間隙值以及壓膠輥間隙值都會(huì)直接影響瓦楞紙板的黏合強(qiáng)度和瓦楞紙板的楞高，尤其是瓦楞紙板的楞高。若壓膠輥間隙值減小，即壓力增大，三層瓦楞紙板的楞高就會(huì)降低而無(wú)法達(dá)到標(biāo)準(zhǔn)值，三層瓦楞紙板厚度降低后，后續(xù)印刷工序采用設(shè)定正常壓力值去印刷瓦楞楞高低的三層瓦楞紙板，會(huì)導(dǎo)致印刷不實(shí)，這樣勢(shì)必會(huì)加大印刷壓力，從而二次對(duì)三層瓦楞紙板的楞高造成損傷，導(dǎo)致瓦楞挺度遭到嚴(yán)重破壞。
在正常生產(chǎn)三層瓦楞紙板時(shí)，上述3個(gè)間隙值分別為2.5mm、2.4mm、2.5mm，此時(shí)出板厚度為3.15mm。有時(shí)單瓦楞紙板涂膠后與白板紙黏合過(guò)程中會(huì)出現(xiàn)彎曲現(xiàn)象，或者打膠較差，從而造成瓦楞紙板邊緣開(kāi)膠，此時(shí)操作人員可將壓膠輥間隙值調(diào)小至1.8mm、涂膠輥間隙值調(diào)大至3.3mm，這樣做雖然可以解決瓦楞紙板的黏合強(qiáng)度問(wèn)題，但出板厚度較差(僅為2.9～3.Omm)、瓦楞紙板較軟，無(wú)法保證其抗壓強(qiáng)度，因此必須制定操作規(guī)程，規(guī)范間隙值。
1. Preparation of adhesive
The production of dangerous cartons cannot be separated from adhesives. Reasonable formula and good bonding strength are the basis for improving the compressive strength of dangerous packaging cartons.
When producing packaging cartons in low temperature and humidity environment (such as winter), the proportion of water and adhesive can be appropriately increased. Among them, the viscosity of the adhesive for the production of single corrugated board should be controlled at 15s, and the solid content should be controlled at about 17%; When producing three-layer corrugated board, the viscosity of the adhesive should be controlled at 40s and the solid content should be controlled at 19%. At the same time, the amount of borax is reduced to 4kg to promote the adhesive to penetrate more into the corrugated board.
When producing packaging cartons in high temperature and humidity environment (such as summer), the proportion of water and adhesive should be reduced. Among them, when producing single corrugated board, the viscosity of the adhesive should be controlled at 18S, and the solid content should be controlled at about 18%; When producing three-layer corrugated board, the viscosity of the adhesive should be controlled at 55s and the solid content should be controlled at 2L%. At the same time, the amount of borax is increased to 6kg to increase the film hardness, so as to reduce the penetration of adhesive into the corrugated board, so as to improve the compressive strength of the packaging carton.
2. Clearance value
Only when the gap between the upper and lower corrugating rollers and the pressure roller is reasonable, can the forming effect of the packaging carton be guaranteed, otherwise problems such as corrugation will directly reduce the compressive strength of the packaging carton. During the operation of corrugating machine, the glue gap value of single corrugated board, glue gap value of three-layer corrugated board and glue roller gap value will directly affect the bonding strength of corrugated board and the corrugated height of corrugated board, especially the corrugated height of corrugated board. If the gap value of the squeegee roller decreases, that is, the pressure increases, the corrugated height of the three-layer corrugated board will decrease and cannot reach the standard value. After the thickness of the three-layer corrugated board decreases, the subsequent printing process uses the set normal pressure value to print the three-layer corrugated board with corrugated height, which will lead to inaccurate printing. This is bound to increase the printing pressure, which will damage the corrugated height of the three-layer corrugated board twice, resulting in serious damage to the corrugated stiffness.
In the normal production of three-layer corrugated board, the above three gap values are 2.5mm, 2.4mm and 2.5mm respectively. At this time, the thickness of the board is 3.15mm. Sometimes the single corrugated board will be bent during the bonding process with the white board after gluing, or the gluing is poor, resulting in the opening of the corrugated board edge. At this time, the operator can reduce the gap value of the gluing roller to 1.8mm and increase the gap value of the gluing roller to 3.3mm. Although this can solve the problem of the bonding strength of the corrugated board, the thickness of the board is poor (only 2.9 ~ 3.0mm), and the corrugated board is soft, so its compressive strength cannot be guaranteed, Therefore, it is necessary to formulate operating procedures and standardize the clearance value.
