Cardboard refers to a paper product that is thicker, heavier, and stiffer than paper, generally quantifying over 400g/m2. There are six kinds of binding board thickness: 0.7mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc. The thickness of the commonly used book shell board is 1.5-2.5mm.

Cardboard is one of the main materials for binding processing, especially for indispensable materials such as hardcover, antique thread and various folders. As the bones of the book case, the thickness, tightness, flatness, moisture content, and strength of the cardboard are closely related to the processing effects of the books. Therefore, the type, performance, and quality of the cardboard are understood, and the correct selection is appropriate. The cardboard required for each type of processing is very important for the production of high quality products. Cardboard refers to a paper product that is thicker, heavier, and stiffer than paper, generally quantifying over 400g/m2. There are six kinds of binding board thickness: 0.7mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc. The thickness of the commonly used book shell board is 1.5-2.5mm.

Cardboard is one of the main materials for binding processing, especially for indispensable materials such as hardcover, antique thread and various folders. As the bones of the book case, the thickness, tightness, flatness, moisture content, and strength of the cardboard are closely related to the processing effects of the books. Therefore, the type, performance, and quality of the cardboard are understood, and the correct selection is appropriate. The cardboard required for each type of processing is very important for the production of high quality products.

Bookbinding type and performance

There are three kinds of common paperboard for binding, namely, gray board, grass board and yellow board.

1 gray board white paper

Dull whiteboard paper, also known as bookcase cardboard, is a type of cardboard that is designated as a bookcase in the national industry standard. Since the late 1970s, it has been applied to the production of book shells, and the effect is good. It has been used up to now.

The gray-white board paper is made of multi-layer (usually three-layer) structure made of groundwood pulp, semi-chemical wood pulp, straw pulp and the same waste pulp. The gray-white paper surface is smooth (calendered) and suitable for making all kinds of book cases.

Gray-white board paper is currently the most widely used type of cardboard for making book cases and folders. Due to the stringent material selection and production requirements of this kind of paperboard, it has the advantages of proper water content, small elongation, good elasticity, proper tightness, smooth surface, and not easy to deform after being glued. This is a processing unit for books and periodicals. It was favored and was identified as a special cardboard for the book case.

At present, there are many manufacturers of gray board in China, but the product quality is not stable enough. There are often problems such as uneven board surface, excessive moisture content, large thickness tolerances, inaccurate layers (cutting and easy layering), and block defects. It has caused great trouble for the binding processing. Although the quality of products has improved in recent years, the impact of imported cardboard is still inevitable. In order to ensure the smooth progress of processing, the following points should be taken into account when using grey-end whiteboard paper.

(1) According to the grade of the workpiece, choose the appropriate grade of cardboard, and choose the appropriate thickness according to the thickness of the book, the size of the format, etc.

(2) When the water content of the board purchased in winter is too large, do not rush to use the material. Store it for a period of time to allow the water to evaporate naturally and use it after the ambient humidity reaches a balance. Do not dry after drying. This will cause the size of the bookcase to shrink and prevent it from fitting with the book block.

(3) When using the automatic hot stamping machine, if it is found that the tolerance of the paperboard thickness is large, it must be checked and selected beforehand, and the thickness may be roughly divided. It may also be processed by a manual hot stamping machine.

(4) When the material was found, the paperboard layer was found to be poorly adhered (stratified). At this time, neither the paperboard nor the medium-diameter paperboard would be cut to a small size. The appearance of unevenness, convexity, warping, etc., affects the appearance of books.

Gray whiteboard paper format is generally 1100mm × 800mm, 1350mm × 920mm and several other types, using the flat form of packaging, each piece weight does not exceed 250kg.

2. Grass cardboard

Grass cardboard is also called horse dung paper. Its surface is rough and yellow. The main raw material is straw fiber. Grass cardboard is a kind of binding cardboard used earlier in our country, and it is also a kind of cardboard that is widely used. The thickness of grassboard is generally 0.7mm, and the thickness can be increased after twisting. This kind of cardboard has low tightness, high elongation, poor toughness, strong surface moisture absorption and penetration, and it is easy to warp and deform due to moisture penetration after the rubber is glued. However, it has low price and can be used for processing low-grade book shells. Due to the differences in raw materials and processing technology between grey cardboard and white cardboard, the following points should be noted when using this type of cardboard for book covers.

(1) Do not hurry to use after buying grass cardboard. Store it for a period of time to make it smooth and obtrusive.

(2) When it comes to wet cardboard, it must be stored for a period of time to allow it to dry naturally to a certain degree before use. If conditions can be used before the use of pressure platen heating (heating temperature is generally at about 65 °C), pressure, so that the rough surface of grass cardboard flat, tight increase, humidity appropriate (to save a reasonable internal moisture).

(3) When the book shell is pasted, apply a binder with less moisture, fast drying, and good viscosity, and improve the scouring process so that the sealing force (sealing 2 and sealing 3) is greater than the sealing force and avoids post-processing. The book shell warps outward.

(4) When making a book cover with a size of 16 or more pages, it should be lined with a single liner in order to achieve a balance of greater surface tension.

The width of grassboard is generally 1092mm×787mm, 787mm×660mm, and 787mm×546mm, and it is packaged in the form of a flat plate. The weight of each piece is generally not more than 150kg.

The quality of grass paperboard is lower than that of gray paperboard, but its price is low. It is used for general medium and low-grade books. As long as the scientific method is used in the process, the quality can be guaranteed.

3. Yellow cardboard

Yellow cardboard is a kind of cardboard which is smoke-brown (the same color as kraft paper), with smooth surface, hard texture, and high toughness. It is commonly used for shoes (doing hall bottom) and box making (internal bones). At the time of binding, it is mainly used for the manufacture of outer envelopes and partial book envelopes for books. The outer envelope of a book made of yellow cardboard is durable and hard to wear, and can protect books and improve the quality of books. Because of its high tightness and small thickness error, it is also conducive to grasping the hot stamping pressure. There are two main forms of outer envelopes for making books with yellow cardboard: one is using yellow cardboard to indent and die-cut and then directly paste into the envelope; the other is to make a layer of paper or fabric on the surface after making the envelope. Material, used to decorate the appearance of the envelope. The following points should be noted in the processing when making shells and sleeves.

(1) The yellow cardboard is hard and has high toughness. Once warping and deforming is difficult to correct, the press or stacking method is applied after the shell to give a certain pressure to prevent warping and deformation of the book case.

(2) Yellow board hardness, suitable for hot embossed imprints, and strong and durable deformation, but the stamping pressure is greater than other cardboard.

(3) When finishing the lining of the finished product, it is necessary to make the sealing pull greater than the external pull, so as to prevent the upward pull of the book shell from warping upwards and it is not easy to level.

The yellow cardboard is generally 1350mm x 920mm, 1120mm x 990mm, etc., and is packaged in a flat plate. Each piece weighs no more than 250kg.

Card type and performance

Jam is a kind of paper product with a thickness between the paper and the cardboard. Its basis weight is generally between 250 and 400 g/m2. There are two kinds of cardboard: one is a double-sided white card, and the other is a gray card (white on the surface and gray on the bottom).

1. Gray Card Gray card is also called single-sided gray cardboard. It consists of three layers: the surface is white, smooth and flat, and can be printed; the middle layer is a filler layer, and the raw material is poor; the bottom layer is gray and rough. The gray card texture is soft, thin, crisp, and resistant to folding, and the bottom layer is hygroscopic. It is commonly used in various kinds of packing boxes. After compounding, it can be used as a stamp album, CD sleeve, etc.

Stapling uses this material mainly for the processing of soft bookcases, looper liners, slipcovers, medium-diameter cardboard, and bookbacks. Gray card used in the binding should pay attention to the following points.

(1) When making soft shells, appropriate adhesives should be selected according to the material to be adhered to prevent stickiness or deformation.

(2) When using a flat-lock adhesive-backed paper jam, soak it in hot water for about 10 hours before use so that the paper is soaked and soft. Then use a small amount of animal bone in the soaking water to prevent cutting. When raising the hair line).

(3) When the looper is hard-linered, the bottom surface should be glued to the loop lining, because the bottom surface is rough, the penetrating power is strong, the paper is easy to bond, and the surface layer can be exposed to facilitate the nesting of the book block and the book cover (insertion sleeve) .

(4) When used in the book case medium-diameter paperboard, care should be taken to be limited to the round-backed book case, not to the back ridge, and the adhesive surface should be exposed at the bottom.

(5) When the gray card is used for compounding, attention should be paid to the selection of the adhesive and the correct application of the adhesive application process, so as to ensure that the composite is flat and firm and does not separate from the layer.

2. White card (double white)

The white card is higher than the gray card, and the white card is composed of three layers: the surface layer and the bottom layer are white, smooth and flat, and can be used for double-sided printing; the middle layer is a filler layer and the raw materials are poor. The white card texture is relatively hard, thin and crisp, and has a wide range of uses, such as various high-grade packaging boxes, cigarette cases, cups, and children's books. The white card for binding is mainly used for soft-faced book cases, paperback covers, manuals, and hard linings.

Cardboard storage and storage

The correct storage and storage of cardboard (including cardboard) is one of the most important factors in guaranteeing the quality of books and books.

Storage condition

Cardboard should be stored in a well-ventilated warehouse or workshop, with appropriate temperature and humidity. Cardboard should not be exposed to moisture, so as to avoid deformation or aging separation; also can not be placed in the open air, because the cardboard itself needs to maintain a reasonable amount of water inside, if the cardboard long-term exposure to the sun, heating baking, etc., will make the normal moisture evaporation, the fiber becomes brittle , Reduced strength, resulting in surface warpage, causing unnecessary losses.

2. Storage method

The purchased cardboard must first understand the production date, the short delivery time and the cold pressure method must not be used immediately, and must be stored for a period of time before use. Because the newly-purchased cardboard is generally more flexible and less flexible, after a reasonable period of storage, it can make the cardboard less flexible, flexible, flat and neat and easy processing.

The time for storing cardboard is generally 3 to 6 months. If the cardboard is stored for more than 1 year, it is necessary to carry out a stockpile to balance the moisture content of the cardboard stack. When storing, care should also be taken to stack the paperboard on the paper table and avoid direct contact with the ground.