Often use vacuum bags friend must have met a vacuum packaging is faulty, vacuum packaging bags small make up detailed anatomy for everyone today, vacuum packaging bags appear smell has the following four effects: one, the influence of the resin itself 1, film is usually made by a high molecular weight resin, resin is composed of molecular sizes, and different molecular weight distribution of the resin, the content of low molecular is different also.
Low molecular substances in extrusion process is easy to oxide volatilization, smell.
2, resin synthesis process solution method and meteorology act, two different synthesis itself also have differences in odor: after removing solution after solution method in the synthesis of the process, a lot of low molecular substances is to get rid of, so the taste is better than meteorology act in theory.
3, to add a lot of additives to improve the performance of the resin, the additive is the largest source of taste: smooth agent is generally amido compounds, some sweet taste.
Antistatic agent very pungent taste, may not be used in low odor packaging.
Opening agent general is given priority to with inorganic substances, usually of calcium carbonate and silica.
But in terms of opening effect, and silicon dioxide is far better than that of calcium carbonate.
But as for the taste of calcium carbonate is better in silicon dioxide.
Antioxidants are usually phenol kind thing, have some flavor.
General linear molecule with catalyst residue problem, so you must add antioxidants.
Commonly used white color masterbatch, masterbatch usually add some wax and stearate as dispersant and lubricant.
These low molecular substances will precipitate during processing, the taste is very big, therefore in the multi-layer co-extrusion as far as possible in the middle.
Second, the influence of membrane process in general processing temperature, the higher the smell are produced.
Because in the processing of high temperature resin of low molecular substances in the environment will be more volatile.
Due to the high temperature oxidation and produce a small amount of carbonic acid, aldehyde, etc can cause very strong smell.
So stretch processing theory will be higher than the taste of blown film.
A cold inside equipment must be better than no cold equipment.
The lowest in the taste of water.
Three, flexible packaging and processing process shall not consider the influence of the flavor of the film, ink, adhesives, solvent and in the flexible packaging processing compound printing process control effect on taste of thin films is very big also.
1, the printing ink has the branch of benzene, no benzene, no benzene class and polyurethane and alcohol soluble ink, different base material use different ink, each series of ink for resin, paint different tastes differ in thousands ways.
So choose low taste, solvent release ink with good effect is particularly critical in the flexible packaging processing.
2, we usually use in composite processing is a two-component solvent-based polyurethane adhesives, two-component solvent aliphatic adhesive and bi-component solvent free pu adhesives, etc. , in order to keep the bags of different performance requirements, on the choice of adhesive, there are a lot of knowledge, a variety of brands of adhesive function is very strong, the performance difference is relatively large, so we should not only consider the adhesive on the choice itself to film strength between taste and to take into account the influence of compound layer whether meet the requirements of customers to use.
3, we found that in odor evaluation of membrane used for dilution of the adhesive solvent in printing ink and composite process without fully evaporate, would lead to excessive solvent residues in composite membrane interlayer, the migration of solvent after a slow, gradually contact with contents, bring some changes to the taste of food, and thus set a reasonable process parameters, is very important for effective online.
In addition, with the rapid development of industry in recent years, solvent-free coating technology has been widely adopted, it can effectively avoid solvent residual risk, it should be said that composite processing a good choice.
Four, the placement of storage conditions of resin and finished products to far away from the odor source.
Placed in odorous environment for a long time, stimulating molecules can cause the taste of some special adsorption on the surface.
The same is true in transit.
Storage temperature is lower than 35 degrees, or low molecular substances will migrate out fast, leading to higher taste.
In the processing workshop environment temperature is not too high, or low molecular substances in the process of production will precipitate.
Anyway, if you want to achieve the goal of low odor, first consider chooses on thin film design formula of resin, the formula of all kinds of additives to as little as possible, as far as possible the processing temperature is low, had better choose to take under cold equipment or blow water cooling process.
Only in this way, the soft bag factory to achieve customer satisfaction, low taste of the film.