Coated cardboard: features, density and types

2024 Author: Sierra Becker | [email protected]. Last modified: 2024-02-26 03:46

Many of us have daily contact with products made of cardboard. Their main difference is the material itself - cardboard differs in density, shade, size, price and surface roughness. One of the most common is coated cardboard.

What is chalking?

The coating process is the application of a special coating to cardboard or paper, which gives them gloss and specific properties. The composition applied to the surface consists of plasticizing and adhesive elements and various pigments, which are kaolin or chalk. Coating is carried out in several ways: machine, cast and non-machine. The last two types require the use of special equipment, while the first can be carried out on conventional paper machines.

There is another kind of coating - scraper. This method consists in spraying an excess amount of coating on the surface of cardboard or paper, which is then smoothed out using a long thin plate - a scraper.

Depending on destination,Coated cardboard can be coated with several layers of composition. A large number of layers gives the material a shine, an attractive appearance, and its surface has a snow-white tint.

What is coated board?

Coated board, or chrome board - a material on the surface of which a special coating is applied, consisting of glue, pigment and plasticizer. It can be of several types: design, packaging and printing.

Depending on the purpose for which the chrome board is made, it may differ in the number of layers and thickness of the coating, double or one-sided coating.

Characteristics of coated paperboard

The main properties of coated cardboard, which are paid attention to when buying it, are:

• Rigidity.
• Strength to delamination, fracture and tear.
• Absorption.
• Weight, density, size.
• Resistance to bending, moisture, bursting.
• Number of layers and surface whiteness.

The quality of the raw materials used in the production and the method of processing the layers directly affect the mechanical properties of the cardboard.

A layer of adhesives and dyes is applied to the surface of the cardboard using special coating equipment. The composition is sprayed both in one and in several layers. In multi-layer coating, a maximum of three layers are applied to the front surface of the cardboard, and one to the back.

The thickness of the application of layers varies from 4 to 40g/m². Depending on the thickness of the coated layer, the printing characteristics of the cardboard change. Coated paperboard, whose density is 230-520 g/m^{2, can be used in various fields of human activity.}

Often, coated paperboard is referred to by terms such as triplex and duplex.

1. Duplex is the most common type of cardboard. The number of coating layers does not exceed three, it is mainly used for packaging. Multi-layer coating is performed according to the classical scheme: one layer is applied to the reverse side of the sheet, three or two layers are applied to the front side. The top and bottom layers are made from high-quality raw materials - bleached waste paper, cellulose or wood pulp. The insert is made from low quality recycled paper, pulp or wood pulp;
2. Triplex is an expensive and high quality type of cardboard. The quality and composition of the material of the liner does not change. The front and back layers are double-sided coated, which is why their properties are strikingly different from those of the duplex.

Differences between coated and uncoated board

The main difference between coated cardboard is the application of a special composition to its surface. White coated paperboard with a smooth surface is significantly better than uncoated counterparts for long-term print retention, as it is mainly used for markings, text signs and brand logos.

Coated paperboard is often used to produce products that cannot be made from conventional paperboardfor aesthetic reasons, since coated surfaces can be printed or varnished. The disadvantages of such cardboard can only be attributed to its high cost.

Coated board classification

Coated board according to the European classification is divided into several categories: SBB, FBB and WLC.

The first category - SBB, or SBS - means cardboard made from bleached pulp and coated on one or both sides with a coated coating. Product weight - 185 to 390 g/m2.

The second type - FBB - is also called chrome ersatz. Its density is 170-850 g/m2. It consists of three layers, the liner is made of wood pulp, the lower and upper layers are made of chemically bleached pulp. Both sides of the cardboard are coated.

The third type is WLC. It is a coated paperboard made from recycled paper with a small addition of wood pulp. The insert is made of cheap cardboard, and high quality waste paper is used for the manufacture of the lower and upper layers. Chalking is done on one or both sides.

In the German classification, coated paperboard is divided into four categories: uncoated, duplex, triplex and cardboard made from virgin fibres. The manufacturer of the material sets its own marking.

According to Russian standards, coated cardboard is marked with the letter "M" and some others indicating additional properties. For example, MNO - coated cardboard on an unbleached basis, MO -cover, the cover is made from it. Coated bleached paperboard – M.

Advantages of coated board

The main advantage of coated board is its versatility. The distinctive features of chrome cardboard include glossy sheen, whiteness, high-quality composition, and the ability to use varnishes. Colored cardboard coated for a long time retains clarity, brightness and saturation of the hue. The quality of the materials used and the number of layers of coating play an equally important role in maintaining color.

Chromeboard is used very widely, thanks to which its production is cost-effective and fully pays off, not to mention the fact that in some production areas it is simply irreplaceable.

Scope of application

Initially, cardboard was created and used as an environmentally friendly and safe, affordable, cheap and convenient container for packaging, storage and shipment of pharmaceutical, food, agricultural and light products, protecting it from various influences. Over time, cardboard packaging has become widely used for advertising, marking and marking. It is not uncommon for a coated board box to be made to produce high quality packaging.

To create a high-quality coating, the top layers of the front surface are fully coated. This type of cardboard is mainly used for varnishing, embossing and transferring images frombright colors. This includes not only packaging tubes, boxes and boxes, but also children's products - toys, kits, printed materials, booklets and covers.

High-quality cardboard is used in almost all industries that impose special requirements on the smoothness and whiteness of the surface of the product. Coated cardboard is often used as packaging for gift and food products.

Cardboard recycling

Coated cardboard is disposed of in the same way as ordinary cardboard. Waste paper recycling in the Russian Federation falls on those enterprises that have been working in this service for a long time. The capacities of such corporations allow processing about 50 thousand tons every year.