Moisture proof technical analysis of the hottest e

2022-08-02
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Abstract: in recent years, with the improvement of people's living standards and quality and the change and development of the mailing market, people have put forward higher requirements for envelopes, which are closely related to our daily life. Various personalized and functional envelope design technologies have been applied in envelope production

key words: envelope technology analysis moisture proof living standard design technology personalized functional mailing

within ± 1% of the set value; When the speed is ≥ 0.05%fs/s, in recent years, with the improvement of people's living standards and quality and the change and development of the mailing market, people have put forward higher requirements for envelopes, which are closely related to our daily life. Various personalized and functional envelope design technologies have been applied in the production of envelopes

moisture proof technology - as one of the technologies of envelope functional design, it has attracted more and more attention in recent years. Because it is suitable for long-distance mailing, and has moisture-proof function for the storage environment and transportation environment of mailing products, it can well protect the safety of mailing products, and can be widely used in food, electronics, medicine, machinery, instrumentation, military industry and other industries, so its market potential is huge, The development value is considerable. Foreign countries have carried out research and development earlier. Countries such as India even have special envelopes with moisture-proof function. However, the production and development of special envelopes in China started late

1 envelope moisture-proof technology

1.1 the reason is that we know that the mailbox is generally placed outdoors for people to post. However, in rainy days, the air humidity is very high, which will inevitably affect the letters in the mailbox and cause them to be damp. In addition, in some inland cities, due to the large temperature difference between day and night, it is easy to form dew drops on the surface of envelopes, resulting in serious damp of letters. We have conducted a humidity change experiment on envelopes day and night, as shown in Table 1

from the table, we can clearly see that the moisture content of the envelope paper is affected by the humidity change of the air from the coast to the mainland day and night. In particular, the closer to the mainland, the more seriously the envelope paper is affected by moisture, and even the letter handwriting may become blurred. In addition, due to the increase of international exchanges in recent years, it is difficult to boost the domestic demand orders between countries, and the number of letters has also increased. However, because the temperature and humidity in different latitudes change with each other, the relative humidity changes with the latitude. See Figure 1 for the approximate change law of the relative humidity in the northern and southern hemispheres

in this way, the humidity change caused by the change of latitude during the transportation of international letters will greatly increase the probability of envelopes being affected by moisture. In order to overcome the problems of the above envelopes during storage and transportation, it is necessary to design an envelope with moisture-proof function

1.2 moisture proof technology

paper is characterized by non-toxic, flammable, rigid, opaque, easy to print, good adhesion, box, etc. it is used in large quantities. By making use of its advantages of easy printing and rigidity, paper can be combined with various plastic films, or even aluminum foil, which can give full play to its advantages. This technology is widely used in various packaging such as milk, fruit juice, cigarettes, tea, coffee, etc, However, although the title of this article indicates that periodic weighing of ingredients is rare in China, we will discuss the development of a special envelope with moisture-proof function by using paper as the substrate and laminating the film (see Figure 2)

1) selection of envelope base material

its disadvantages are high permeability, poor moisture and moisture resistance, and low mechanical strength. Paper can be used alone as packaging materials, especially as cardboard boxes, cartons, functional protective packaging paper, packaging and decorating paper, kraft linerboard, white paper, corrugated paper, etc., which can be used as packaging paper. However, different paper materials show different properties and application ranges. See Table 2

comparison of several commonly used functional household paper. We can see from the table that different papers have different properties and application ranges, and we mainly consider the following three aspects when selecting moisture-proof base materials

. It has the characteristics of light weight, opacity and high strength. In addition, it also meets the requirements of the national standard for envelope paper, and the surface is convenient for writing and printing. In addition, environmental protection and pollution reduction should be considered when selecting materials, and pollution-free packaging materials should be used as much as possible. Therefore, we choose composite film

i, which conforms to the national standard and is now commonly used in the market

ⅱ. The composite strength with the film is good

Ⅲ. The base material has high strength and opacity, and the books can be written and printed with good performance

considering these factors, we choose kraft paper with good writing and printing effect and strength. Kraft paper is named for its tough and strong quality like cow leather. Kraft paper is a high-grade packaging paper, which is widely used. Kraft paper is divided into single-sided light, double-sided light, striped and non striped in appearance. The quantity of kraft paper is 40g/m2, 50g/m2, 60g/m2, 70g/m2, 80g/m2, 90g/m2, 100g/m2, 120g/m2. With the quantitative increase of kraft paper, the paper thickens, the bursting strength increases, and the tearing strength also increases. Its protective performance is grade B kraft paper, and the reflectivity of kraft paper will not be less than 38%

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