(1) gravure printing

Definition: a method of direct printing, in which the ink contained in the concave points of gravure is directly imprinted on the substrate.

(2) Flexographic printing

Definition: printing method of transferring ink to substrate by elastic relief.

Gravure printing picture

Small characters and lines of flexographic printed pictures (1) should be designed as a single package to avoid multi-color misregister. The width of thin thread should not be less than 0. 1mm, otherwise it will be easily lost or unclear when printing. The clear height of Chinese fonts shall not be less than 1.8mm, and that of English fonts shall not be less than1.5mm. ..

(2) Pay special attention to the design of prominent characters. If the text is small, especially if the strokes are thin, please use monochrome. We should also pay attention to the selection of fonts, such as round head, bold body, isobar body, etc., while fonts with too big difference in strokes, such as Song Ti and Lao Song Ti (horizontal thin and vertical thick), should be used with caution. If this font is used in the design, it should be noted that the clear height of Chinese font is not less than 2.5mm, and the clear height of English font is not less than 2 mm, and it can only be used after being made into various packaging bags with warm-printed composite soft packaging materials. There are two ways to make bags. One way is that the packaging factory fills the rolled film in the automatic packaging machine and shapes it into various packaging bags. The other is because the bag-making machine makes all kinds of packaging bags and then loads the contents. Because the professional bag-making control is accurate, the bag shape is beautiful, the bag-making changes greatly and there are many bag types, so in quite a few cases, the bag is made first. The main types are: three-sided sealed bag (folding bag), back sealed bag, folding bag (organ bag), upright bag and so on. , as shown in the figure below.

Figure 1

Three-sided sealed bag

Figure 2

Back sealing bag

Figure 3

Bellows bag

Figure 4

Upright bag

Vacuum packaging is mainly used for food packaging, such as meat, cereal processed food and food that is easy to be oxidized and deteriorated. It can also be used for fluffy products such as mechanical parts, instruments, down products and wool products.

With the gradual improvement of people's living standards and quality of life requirements, vacuum packaging has occupied an indispensable position in contemporary people's lives. It is a typical vertical extension of packaging technology and plays an irreplaceable role. Vacuum packaging, in short, its most important function is to remove oxygen, thus helping to prevent food from spoilage.

The principle of vacuum packaging is simple. The main cause of food mildew and deterioration is the activity of microorganisms, and the survival of microorganisms (such as mold and yeast) needs oxygen. Vacuum packaging is to use this principle to extract oxygen from packaging bags and food cells, so that microorganisms lose their "living environment." At the same time, it also prevents food from being stale and deteriorating due to oxidation, thus achieving the effect of long-term storage and preservation of food. The properties of food vacuum packaging materials directly affect the shelf life and taste changes of food. In vacuum packaging, selecting good packaging materials is the key to successful packaging.

When it comes to vacuum packaging materials, it is essential to classify the materials. The following are the characteristics of various materials suitable for vacuum packaging:

1.PE is suitable for low temperature use, and RCPP is suitable for high temperature cooking;

Secondly, PA increases physical strength and puncture resistance;

Third, aluminum foil is to increase the barrier performance and shadow;

Fourthly, PET increases the mechanical strength and has excellent rigidity.

Then, according to the demand, combination and various properties, there are also transparent, water-resistant PVA high barrier coatings to increase the barrier performance. Generally speaking:

PA/PE or PA/RCPP

PET/PE or PET/RCPP

There are also three floors and four floors. In order to improve the texture and properties of materials:

PET/PA/PE

PET/AL/RCPP

PA/AL/RCPP

PET/PA/ AL/RCPP retort pouch, vacuum bags are used to package all kinds of cooked meat, which is convenient and hygienic.

Materials: NY/PE, NY/AL/RCPP, NY/PE.

Features: moisture-proof, temperature-resistant, shading, fragrance-preserving and strong.

Application: high-temperature sterilized food, ham, curry, roasted eel, grilled fish and gravy products.

At present, the most widely used vacuum packaging is film material, of course, there are also bottles and cans. The film materials used in food vacuum packaging should ensure the best packaging effect, aesthetics and economy of various foods. At the same time, vacuum packaging of food also requires high light resistance and stability of materials. When a single material cannot meet these requirements, packaging is often composed of many different materials. 1, high barrier property: the film is extruded by using the high barrier properties of different plastic materials to achieve the effect of high barrier to oxygen, water, carbon dioxide and odor.

2. Stable performance: oil resistance, moisture resistance, low-temperature freezing resistance, quality preservation, freshness preservation and taste preservation, and can be used for vacuum packaging, aseptic packaging and inflatable packaging.

3. Low cost: Compared with plastic packaging such as glass packaging and aluminum foil packaging, to achieve the same barrier effect, * * * extruded film has great advantages in cost. Due to the simple process, the cost of the produced film products can be reduced by 10-20% compared with dry composite films and other composite films. 4. Flexible specifications: can meet your different needs for different products.

5. High strength: * * The extruded film has the characteristics of stretching during processing, and the strength of plastic after stretching can be improved accordingly. Nylon, polyethylene and other plastic materials can also be added in the middle, so that it has a composite strength that exceeds that of ordinary plastic packaging, does not delaminate, has good flexibility and excellent heat sealing performance.

6. Small volume ratio: * * Extruded film can be packed in vacuum, and the volume ratio is close to 100%, which is incomparable to glass, tin cans and paper packaging.

7. No pollution: no adhesive is added, no residual solvent pollution, and environmental protection.

Vacuum packaging bag is moistureproof+antistatic+explosion-proof+anticorrosion+heat insulation+energy saving+single perspective+ultraviolet shielding+low cost+small volume ratio+no pollution+high barrier effect. Vacuum packaging technology originated in the 1940s. Since the plastic film was successfully applied to commodity packaging in 1950s, vacuum packaging technology has developed rapidly. The level of packaging reflects a country's scientific and technological level and wealth to a certain extent. The research and application of vacuum packaging technology in China is still in its infancy.

1. In 1962, Ordal proposed that the oxygen impermeable membrane can inhibit the growth of pathogenic microorganisms, and packaging fresh meat can prolong its shelf life.

Secondly, Baltzer thinks that the shelf life of vacuum-packed fresh meat is longer than that of oxygen-packed fresh meat because:

(1) The total number of microorganisms increased slowly under anaerobic conditions;

(2) decay and mucus reduction;

(3) After storage, the number of final microorganisms in vacuum packaging is less than that in aerobic packaging. This shows that after the oxygen in the vacuum packaging of fresh meat is converted into carbon dioxide, the oxygen-tight film can prevent external oxygen from entering the packaging, so vacuum packaging can prolong the shelf life of fresh meat.

Thirdly, in 1970, Pearson et al. proposed that vacuum packaging created an "ecosystem" for selecting microbial species and levels. 1974, SCOPA company first applied MAP (Modified Sphere Package) to meat packaging.

4.Pesis et al. (1986) put forward that vacuum packaging is the best preservation method to keep persimmon fruit quality and hardness. It can be seen that the development and popularization of storage and preservation technology are paid more and more attention by producers, operators and consumers.

Another part of the equipment needed for vacuum packaging is the packaging container. There are many kinds of packaging containers, including composite materials such as plastic, paper and aluminum foil, glass bottles, metal containers and hard plastics. The choice of packaging containers should be based on the nature of vacuum-packed food, such as glass bottles or metal cans for canned food and aluminum foil or plastic for Chinese herbal medicines. Although there are many kinds of vacuum packaging containers, the most common one is plastic film. If you ask us, what kind of packaging bag should we choose when choosing packaging bags? So, let's introduce it to you: So what is the reason? Next, I'll introduce you to two reasons.

First, it has a good "gas barrier". We know that things, especially food, are particularly afraid of oxygen, because oxygen is an important basis for the survival of many creatures. But bacteria are also living things. Some bacteria can multiply in large numbers in the presence of oxygen, and will never endanger the quality of food and other items. The vacuum packaging bag, as its name implies, must be in a vacuum or near vacuum state in order to play a good "gas isolation role." In fact, vacuum packaging bags can not only isolate oxygen, but also isolate gases such as carbon dioxide.

Second, vacuum packaging bags are safe to use. The vacuum packaging bag adopts the "green" production concept, and no chemicals such as adhesives are added in the production process, so it is a green product. Vacuum packaging bag is a product packaging method, in which the air in the bag is pumped out and sealed after the product is put into the bag. Some long-distance oily foods, such as halogen products, ham, grilled fish, Beijing roast duck, Texas braised chicken and other oily foods that are easy to deteriorate after long-term contact with oxygen in the air, must choose vacuum packaging bags, and it is best to cook at high temperature. The packaging bag sterilized at high temperature not only provides a safer storage environment for food, but also ensures the safety of the aluminum foil bag itself. In addition to high-temperature cooking sterilization technology, it also provides aluminum foil reflective materials that can perfectly avoid light for foods that cannot be exposed to sunlight. In order to prevent the bag from being punctured, PA was specially added. With vacuum packaging bags, the fresh taste and color of oil products can be preserved until Kaifeng.