Corrugated board performance improvement (on)

Keywords: packaging, corrugated, corrugated board, functionalization

In the increasingly serious environmental pollution and destruction, the development and application of green packaging materials with good compatibility with the environment has become an inevitable trend. Therefore, the paper packaging has been further developed.

Among many paper materials, corrugated paperboard is an indispensable material for manufacturing packaging containers because of its unique advantages such as light weight, low cost, high bending strength, high adaptability to processing and structuring, and good printability. So far, corrugated cardboard has become one of the most widely used packaging materials in modern packaging, and its usage is steadily increasing. It is expected that by 2010, the world demand for cartonboard will increase at a rate of 2.8% per year and reach 125 million tons by 2010. According to the forecast of experts, in 2005, the consumption of paper and paperboard in China was about 50 million tons, and the consumption of corrugated paperboard and paperboard would be measured at 30%. By that time, the consumption of corrugated paperboard in China will reach 15 million tons. With China's accession to the World Trade Organization, the demand for paper product packaging is even greater. This is undoubtedly the development of corrugated paper packaging, bringing with it a golden opportunity for development J. As a product packaging, its main function is to protect the performance. In addition, people also pay great attention to the Decoration of the packaging and attracting effect. With the improvement of the material and cultural living standards and the development of the packaging industry, the performance requirements of corrugated paperboard by packaging designers are getting higher and higher, which promotes the development of corrugated board structure and functionalization, and the performance of corrugated board is continuously improved. Improve.

1, the application of micro watts

Corrugated high and low density and density affect the strength characteristics of corrugated board, according to the provisions of GB/T6544-1999, may have four kinds of rake type shown in Table 1 for packaging design choice.

Generally, the corrugation height is high and the cushioning property is good because of its large cross-section size and good edge compressive strength. On the other hand, there are many corrugated ridges, and there are many support points in the plane, and the flat pressing strength is high, and the printing effect on the plane is also good. The general type C is the most commonly used. In a multi-layer corrugated cardboard, a layer of a C-type structure is contained. Type E is suitable for small and exquisite packaging, or for internal packaging.

In recent years there have been smaller-sized corrugated sheets, called micro-flutes. The original A, B, and C size corrugated sheets can be used as outer packing boxes to obtain cushioning and protective properties, and solid cardboard is often used as the inner packing and packing cartons. Microwax is used instead of solid cardboard to make interior and sub-carton boxes. This kind of micro-wax has more advantages than solid cardboard, such as: light weight, good cushioning, saving resources, the surface layer and core layer of the paperboard can use different quality of raw paper, good heat insulation, lower cost and so on. Table 2 shows the specifications of several microvars.

With these corrugated corrugated paperboards, the lower embossing height makes the paperboard structure firmer, while the smaller twisting distance increases the flat-pressing performance of the paperboard, and provides a smooth surface, so that it can be directly offset, The pattern printing effect is the same as that of the folding box board, minimizing the wrinkling of the board.

2 functional corrugated cardboard

The so-called functional corrugated paperboard, through some kind of processing or processing, makes the corrugated board obtain some function and improve its performance. There are mainly three kinds of processing and processing technologies for functional corrugated board: (1) Secondary processing or coating, or impregnation, or compounding of the produced corrugated paper or corrugated board, through a series of physical or chemical Processed to produce packaging containers with special properties that can meet special needs; (2) To modify paper fiber materials, that is, to add functional additives to the original papermaking raw material ingredients; (3) Select specific raw materials and press for normal copying Paper process, made of corrugated paper with waterproof, preservation and other functions.

2.1 Recyclable waterproof corrugated cardboard

Waterproof corrugated cardboard can be used to package frozen or fresh fish and aquatic products, or used as a vegetable box that needs to be pre-cooled, and a fish processing box. In the past, waterproof corrugated paperboard was mainly processed by two methods: one was to dip wax or wax the corrugated board; the other was to coat the surface of the base paper made of corrugated paper with wax emulsion or wax, or compounded with plastic film and metal foil. , and then made of corrugated cardboard. Although these corrugated cardboards have good water resistance, they are difficult to recycle. In order to protect the environment and save resources, people have recently focused on the development of recyclable waterproof corrugated cardboard. There are two main types: (1) Apply a water-repellent agent that does not affect recovery and regeneration on the surface of the linerboard. (2) Coat the surface of the liner and corrugated paper with this water-repellent agent that does not affect recycling. This will not only prevent water from penetrating into the interior of the corrugated medium, but also make the starch adhesive between the core paper and linerboard water-resistant. It has been greatly improved. The key technology of these two types of waterproof corrugated paperboards is the development of water-resistant coatings that do not affect recycling. General latex and latex coating, coating amount 4-15g/m2.

A kind of corrugated paper called “Rosin paper” in southern China is also a kind of waterproof corrugated paperboard. It is made of bagasse, rice straw, and slurry. It is named after relatively increasing the dose of rosin. It has better water resistance than ordinary paper, so it uses it. The corrugated packaging boxes are widely used in the refrigeration packaging and storage of vegetables, fruits, flowers, etc. The advantages are that the carton has higher compressive strength and strong moisture resistance, and generally the cartons enter the cold storage, and the strong force is lost for 2-3d and the stacking deformation occurs. Or collapse, and the storage time of Rosin cartons can be as long as 15 days to one month or even longer, stacking complete.

2.2 Preservative corrugated cardboard

This type of corrugated board is mainly used for the preservation of fruits and vegetables. The key to its preservation is to have certain gas barrier properties, namely, airtight and moisture-proof. In this way, when packaging fruits and vegetables, the CO2 and water vapor produced by the fruits and vegetables can be enclosed in the box, and the concentration of oxygen is reduced to form a high CO2 and high water vapor atmosphere, which is conducive to maintaining the freshness of the fruits and vegetables.

There are two approaches to preservation, 1) combining corrugated boxes with special plastic wraps, preservatives and helium coolants; 2) modifying traditional corrugated paperboards to make them fresh-keeping, which is obviously economical and easy. . The original fresh-keeping corrugated board is compounded with a plastic (polyethylene, polypropylene, etc.) film, or a 2-layer cardboard is pasted with this film. The disadvantage of this type of fresh-keeping corrugated board is that it cannot be recycled and it does not meet the requirements of environmental protection; and because the gas barrier property of the plastic film is too high, the fruits and vegetables are vulnerable to condensation caused by low oxygen and high humidity. The new type of fresh-keeping corrugated board can overcome these two shortcomings. It uses a sodium alginate aqueous solution or a water-dispersible resin to form a gas barrier layer on a paperboard. The gas barrier property of the gas barrier layer is lower than that of a plastic film, and can also be dissociated in water, thereby providing a superior performance and environment-friendly preservation layer. cardboard.

The use of new additives has increased the number of fresh-keeping corrugated paperboards. Recently, a kind of tomaline has been added to paperboard to make use of its negative ions to keep corrugated paperboard for fruits and vegetables fresh, and a silicate stone powder is used as an additive to pulp to make good use of this kind of stone powder for various gases. Adsorption can maintain freshness for a long period of time so that the weight of fruits and vegetables will not be reduced. It is particularly suitable for long-distance storage and transportation. In the pulp, micro-powders of cristobalite and activated carbon are mixed and the corrugated paper produced can not only absorb ethylene gas. It also prevents moisture from evaporating and has a good absorption of hydrogen sulfide that causes spoilage and spoilage of flowers.