Types and applications of binding cloth paper
Cardboard is one of the main materials for binding processing, especially indispensable materials for making hardcover, ancient thread binding and various folders. The thickness, tightness, flatness, moisture content, strength, etc. of cardboard as the bones of the book cover are closely related to the processing effect of books. Therefore, understand the types, performance and quality of cardboard, and choose the right one. The cardboard required for each type of processing is very important to produce high-quality products.
Types and applications of binding cloth paper :
There are 3 kinds of cardboards commonly used for binding, namely gray-bottomed white paper, straw cardboard and yellow cardboard.
1. Grey bottom white board paper
Gray-bottomed whiteboard is also called book cover paperboard, which is a kind of paperboard used as book cover specified in the national industry standard. Since the late 1970s, it has been applied to the production of book envelopes, and the effect is good, and it has been used today. Gray-bottomed whiteboard paper is made of ground wood pulp, semi-chemical wood pulp, straw pulp and the same waste paper pulp in a multi-layer (generally three-layer) structure. The gray-bottomed white paper has a smooth surface (after calendering treatment), which is suitable for making all kinds of book envelopes.
Gray-bottomed white board paper is currently the largest type of cardboard used to make book envelopes and various folders. Due to the strict requirements for material selection and production of this paperboard, it has the advantages of proper moisture content, low elongation, good elasticity, proper tightness, smooth surface, and non-deformation after gluing. It is a processing unit for books, magazines and books. Favored and determined to be a special cardboard for book cover making.
At present, there are many manufacturers of gray-bottomed whiteboard paper in my country, but the quality of the products is not stable enough. There are often problems such as uneven surface of the cardboard, excessive moisture content, large thickness tolerance, weak layers (easy to be cut), and block scars. Brings a lot of trouble to the binding process. Although product quality has improved in recent years, it is still unavoidable from the impact of imported cardboard. In order to ensure smooth processing, the following points should be paid attention to when using gray-bottomed white paper.
(1) The appropriate grade of cardboard should be selected according to the grade of the processed product, and the appropriate thickness should be selected according to the thickness of the booklet and the size of the format.
(2) When buying cardboard in winter when the moisture content is too large, do not rush to open the material for use. Store it for a period of time to allow the moisture to evaporate naturally, and then use it after reaching a balance with the environmental humidity. Do not dry the material after opening, as this will reduce the size of the book envelope and fail to fit the book block.
(3) When using an automatic hot stamping machine to process, if you find that the cardboard thickness tolerance is large, you must check and select in advance, and roughly separate them according to the thickness. You can also use a manual hot stamping machine for processing.
(4) It is found that the cardboard layer is not firmly bonded (separation) when opening the material. At this time, neither cut into small format nor suitable for medium-diameter cardboard, because the cardboard paste between the layers is not strong when it is made into the book cover. The appearance of unevenness, bulging, warping and other phenomena will affect the appearance quality of the book.
Gray-bottom whiteboard paper generally has 1100mm×800mm, 1350mm×920mm, etc., and it is packaged in flat form, and each piece weighs no more than 250kg.
2. Straw cardboard
Straw cardboard is also called horse dung cardboard. Its surface is rough and yellow, and its main raw material is straw fiber. Straw cardboard is a kind of binding cardboard used earlier in our country, and it is also a kind of cardboard with a wide range of uses. The thickness of straw board is generally 0.7mm, and the thickness can be increased after laminating. This kind of paperboard has low tightness, high elongation, poor toughness, and strong surface moisture absorption and permeability. After glue, it is easy to warp and deform due to moisture penetration, but its price is low, and it can be used for processing low-grade book envelopes. Because the raw material and processing technology of straw paperboard are different from that of gray-bottomed whiteboard paper, the following points should be paid attention to when using this paperboard as book cover.
(1) Don't rush to use the straw paperboard after you buy it. Store it for a period of time to make it smooth and sticky.
(2) When encountering damp cardboard, it should be stored for a period of time to allow it to naturally dry to a certain extent before use. If possible, use a cardboard press to heat it before use (the heating temperature is generally about 65°C) and pressurize to make the rough surface of the straw cardboard smooth, tighter, and humidity appropriate (save reasonable internal moisture).
(3) When making the book case by pasting, apply a binder with less moisture, fast drying, and good viscosity, and improve the lining process to make the inner seal (sealing two and three) greater than the outer seal, to avoid post-processing The book cover is warped outwards.
(4) When making a book cover with a size of 16 or more, a single lining should be mounted on the cover to achieve a larger-format tension balance.
The format of straw board is generally 1092mm×787mm, 787mm×660mm, 787mm×546mm, etc. It is packaged in flat form, and the weight of each piece is generally not more than 150kg.
The quality of straw paperboard is worse than that of gray-bottomed whiteboard paper, but the price is low. It is used for general middle and low-end books. As long as the process adopts scientific methods, the quality can be guaranteed.
3. Yellow cardboard
Yellow cardboard is a kind of smoky brown (same color as kraft paper), smooth surface, hard texture, and greater toughness. It is often used for shoemaking (for the bottom of the hall) and box (inner bones). When binding, it is mainly used to make the outer cover of the book and part of the book cover. The outer envelope of the book made of yellow cardboard is durable and not easy to wear, and can protect the book and improve the grade of the book. Because of its high tightness and small thickness error, it is also conducive to mastering the stamping pressure. There are two main types of outer envelopes made of yellow cardboard: one is to make the envelope directly after embossing and die-cutting with yellow cardboard; the other is to paste a layer of paper or fabric on the surface after making the envelope. It is used to decorate the appearance of the envelope. The following points should be paid attention to during processing when it is used to make shells and envelopes.
(1) Yellow paperboard is hard and tough, and it is difficult to correct the warpage and deformation. Therefore, after the case is made, a certain pressure should be applied to the book case to prevent the warpage and deformation of the book case.
(2) Yellow paperboard has high hardness, suitable for hot stamping concave and convex marks, and is firm and durable without deformation, but the hot stamping pressure is higher than other paperboards.
(3) When processing the finished lining, make sure that the tension of the inner seal is greater than the tension of the outer seal, so as to prevent the outer tension from being too large and the book case from warping upward is not easy to level.
Yellow paperboard generally has several formats such as 1350mm×920mm, 1120mm×990mm, etc., and it is packaged in flat form, and each piece weighs no more than 250kg.
Types of jams and performance
Cardboard is a paper product with a thickness between paper and cardboard, and its basis weight is generally between 250 and 400g/m2. There are two types of paper jams: 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, which consists of three layers: the surface layer is white, smooth and flat, and can be printed; the middle layer is a filler layer with poor raw materials; the bottom layer is gray and rough. The texture of the gray card is soft, thin and firm, and resistant to folding, and the bottom layer is highly hygroscopic. It is commonly used in various packaging boxes, and can be used as stamp albums, CD jackets, etc. after being compounded.
This material is mainly used for the processing of soft book cases, looper hard linings, soft book covers, medium-diameter cardboard, and book back cardboard. Pay attention to the following points when using the gray card in binding.
(1) When making soft shells, suitable adhesives should be selected according to the material to be adhered to prevent inadequate adhesion or deformation.
(2) When used for flat-lock sticky book back jammed paper, soak it in hot water for about 10 hours before use, so that the jammed paper is soaked and soft before use (it is better to add a small amount of animal bones in the soaking water to prevent cutting the book. When the hair comes out of the guard line).
(3) When making looper hard lining, the bottom surface should be mounted on the ring lining, because the bottom surface is rough, strong penetration, easy to bond the paper, and the exposed surface can facilitate the processing of book block and book cover (insert sleeve) .
(4) When it is used for the book case medium-diameter cardboard, it should be noted that it is limited to the round-back book case, and it is not suitable for the square back false ridge. The bottom surface of the glue should be exposed.
(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 glue process to ensure that the compound is neat and tidy and firm.
2. White card (double-sided white)
The white card has a higher grade than the gray card. The white card is composed of three layers: the surface layer and the bottom layer are white, smooth and flat, and can be double-sided printing; the middle layer is a filler layer with poor raw materials. The texture of the white card is relatively hard, thin and crisp, and has a wide range of uses, such as making all kinds of high-end packaging boxes, cigarette cases, cups, and children's books. White cards for binding are mainly used for soft-faced book covers, paperback covers, manuals, hard linings, etc.
Cardboard storage and custody
The correct storage and custody of cardboard (including cardboard) is one of the important factors to ensure the binding quality of books and periodicals.
1. Storage conditions
Cardboard should be stored in a well-ventilated warehouse or workshop with proper temperature and humidity. The cardboard should not be damp, so as to avoid deformation or aging separation; it should not be placed in the open air, because the cardboard itself needs to maintain its internal reasonable moisture. If the cardboard is exposed to the sun and heating for a long time, the normal moisture will evaporate and the fiber will become brittle. , The strength is reduced, resulting in surface warpage, causing unnecessary losses.
2. Storage method
You need to know the production date of the purchased cardboard. The production time is short and it is made by cold pressing. It cannot be used immediately and needs to be stored for a period of time before use. Because newly purchased paperboard is generally tougher and less flexible, after a period of reasonable storage, the toughness of the paperboard will be reduced, the flexibility will be increased, and the plain clothes will be neat and easy to process. The storage time of cardboard is generally 3-6 months. If the storage time of cardboard exceeds 1 year, it should be dumped once to balance the upper and lower moisture content of the cardboard stack. When storing, you should also pay attention to stacking the cardboard on the paper table and avoid direct contact with the ground.