Discussion on the selection and current situation

Discussion on the selection and current situation of paper packaging sealants

I. The current situation of the use of paper packaging sealants

many packaging enterprises (including some large printing and packaging enterprises) are expert in printing, but their understanding of sealants is not enough. Many are even blind in the selection and use of sealants, which has brought great losses and waste to packaging enterprises. "Difficult bonding" has become a ghost that puzzles all packaging enterprises, and almost every packaging and printing enterprise is deeply headache

in fact, the problem of "difficult bonding" can be completely solved as long as the choice is good and the adhesive is used well. Summing up the experience and lessons of many packaging enterprises, the problems almost lie in the two links of "selection and use". In order to let many colleagues engaged in technical work, quality management and supply work know more about sealing glue, and make "difficult bonding" become "easy bonding", from "worry glue" to "reassurance glue", our company has compiled this article, with a view to discussing the quality standards and use methods of sealing glue with domestic peers, Make our contribution to the prosperity of the packaging industry led by Professor Yoon won soo

second, the choice of paper sealing glue

1. Understand the use characteristics

any kind of sealing glue is not omnipotent, and a kind of sealing glue can only be suitable for a certain or a specific kind of glued material. The thermal conductivity of some packaging is lower than that of extruded polystyrene board. Enterprises blindly use glue with the mentality of "try it", which not only wastes time and energy, but also causes great losses. At present, the base materials often bonded by packaging enterprises generally include BOPP (biaxial tensile polypropylene film)/paper, polished/paper, pet (polyester film)/paper, high gloss printing paper/paper. In fact, this kind of products only need our multi-functional paper/plastic sealing adhesive, which can meet all the requirements of the above materials, and more than 98% of the products of packaging enterprises are the above materials. In addition, some packaging enterprises have film/film bonding requirements, and our multifunctional plastic/plastic sealing adhesive can be used. In addition to film/film bonding, it can be used for bopp/paper, polishing/paper, pet/paper, high gloss printing paper/paper, but this product can only be used for manual bonding. Taken together, the above two products can basically meet all the bonding requirements of various printing and packaging enterprises. Except for special requirements such as pvc/paper, pvc/wood, uv/paper, these products can be solved with other types of adhesives of our company

2. Quality standard

in addition to understanding the characteristics of the product, we also need to understand the quality of the product. Any kind of sealing adhesive has a certain chemical standard, which is determined by the formula and process. You Yufei, director of plastic additives of BIC additives (Shanghai) Co., Ltd., said in an interview that a good chemical standard must reflect a good physical standard (i.e. application standard). We believe that the most important physical standard (application standard) in the packaging industry is: A, bonding strength (adhesion); b. High temperature resistance; c. Low temperature resistance; d. Moisture resistance; e. Hold viscosity. In many domestic packaging enterprises, the bonding is not firm, or the products bonded within a period of time are degummed, and the adhesive film is brittle, which are basically the above situations (except for the unreasonable bonding process). Therefore, it is often heard that some printing and packaging enterprises say, "some adhesives need to be degummed in hot weather, some adhesives need to be degummed in cold weather, and some adhesives do not need to be stored for a long time in cold and hot weather", In fact, this is due to the lack of a deep understanding of how to choose and use sealing glue. What is more serious is that some sealing glue manufacturers do not know why they want to degumm, and how to design formulas, formulate processes and develop products according to the special requirements of the packaging industry. Therefore, it is not surprising that there are quality problems in the process of use

3. Price

when choosing sealing glue, the quality must be the first and the price the second. Some packaging enterprises blindly believe that the higher the price, the better the quality, or the lower the price, the worse the quality. These views are very one-sided, which leads to some packaging enterprises not only spending money, but also causing great losses. In fact, sealing glue only accounts for a small proportion of the cost of a packaged product, so we think it is reasonable to first seek a suitable price on the premise of understanding the characteristics, quality standards and performance of the product

III. characteristics and application methods of multi-functional paper/plastic sealing adhesive

sealing adhesive is the most widely used adhesive in the printing and packaging industry. Because of its strong and reliable, good adhesion, good high and low temperature resistance, good moisture resistance, moderate hardness, wide scope of application and other advantages, it has been used by many domestic packaging enterprises for a long time, and has been highly praised by many test film packaging enterprises that slide the package and clamping unit together

1. Scope of application

according to the different bonding interfaces, it can be divided into strong and fast bonding of bopp/paper, polishing/paper, pet/paper, paper/paper, ink/paper, UV glazing/paper. This adhesive can be divided into machine bonding and hand bonding, and can also be used both machine bonding and hand bonding, which basically meets the requirements of bonding materials of various packaging enterprises today

2. Product characteristics

① good brushing performance. In case of thin products during manual brushing, water can also be added appropriately to dilute them, and the mixing should be uniform. The amount of water added depends on the model of sealing adhesive and the thickness of the bonded material, and the total amount should be controlled between 2%-10%

② the initial bonding speed is fast, and it can be bonded at high speed on the automatic sealing machine. When bonding manually, it can be pressed for half an hour

③ the adhesive film is flexible, with good adhesion to the laminated surface and polished surface, and high bonding strength

④ good cold and heat resistance. The bonded products are baked at 60 ℃ for 72h or -10 ℃ (refrigerator freezer) frozen for 72h, and the bonding strength basically remains unchanged. The products do not degumm and the adhesive film is not brittle

⑤ the adhesive film has flexibility and long-term pressure sensitivity, and its bonding strength retention is good

3. Usage and precautions

① when using hand glue, it is generally allowed to stand in the air for 2~6min after brushing according to the model of sealing glue, and then glue after the film is translucent, so as to avoid glue overflow

② the glue has certain moisture resistance, so when there is wild glue, it can be gently wiped with cotton yarn dipped in gasoline or ethyl ester solvent, and the container and brush can be washed with water and then washed with solvent

③ due to its fast drying property, this product should not be painted repeatedly to avoid affecting the brushing property

④ the amount of glue should be appropriate. The glue should be applied by manual brushing. Generally, the amount of glue should be controlled at about 100g/㎡ or according to the requirements of the bonding strength of specific products. The specific amount of glue can be determined according to the speed of water absorption of the paper and the temperature. The paper with slow water absorption needs less gluing, less gluing when the temperature is low, and more gluing on the contrary. After bonding, there should be enough pressure according to the stiffness of the bonded product to ensure that the two bonded surfaces are in full contact and pressed for at least 0.5h before entering the next process

⑤ when using machine glue, the amount of glue should be controlled at the outlet of the workpiece without degumming. If the amount of glue is too large, there will be glue overflow, and if the amount of glue is too small, it will affect the bonding strength. For polished products, the amount of glue can be appropriately adjusted to avoid degumming at the discharge end because the bonded substrate is too thin

source: Guangdong packaging