As an important and traditional information carrier, paper production has always been prosperous, and it is increasingly related to printing technology. Economic development, technological advancement, constantly put new demands on the variety of paper, the quality of paper and the performance of paper. In the 1980s, the Chinese printing industry and the Chinese paper industry jointly completed the transition from letterpress printing to offset printing and from the production of letterpress printing paper to the production of offset printing paper. At present, the use of letterpress printing for Chinese prints is rare and rare. Offset printing is almost entirely replaced by offset printing. Although China's paper industry still regards letterpress printing paper as a key product of industry statistics, the actual production is not past letterpress printing paper, and most of them are offset book and paper. There is no stop on the road of development. Modern offset printing requires that the printing paper has a smoother surface, better printing performance, and can withstand large changes in temperature and moisture without curling. Internationally, the variety of printing papers has been extended upwards and a series of new varieties of mechanical pulp printing papers have been developed. In recent years, digital printing technology, office automation and the development of personal computers have brought newer and higher requirements to paper. Internationally, new series of laser printing papers and inkjet printing papers have been developed in the field of chemical pulp printing papers.
Now, consumer demand for print has increased. People not only want to obtain the necessary knowledge and information, but also hope that they can enjoy the enjoyment of beauty and leisure through reading and browsing of printed matter. Therefore, the variety of paper must continue to innovate. The 21st century is the era of knowledge economy. The core of the knowledge economy is innovation. The knowledge economy can also be called "innovation economy." Innovation is also the soul and life of a company. Some forward-thinking papermakers have vowed to “beyond self, develop products, meet market demands, and conscientiously implement the development strategy of aligning the paper industry with the printing industryâ€, which should attract the attention of the paper industry professionals. In a long period of time, the production and consumption of paper will continue to develop steadily. However, the paper varieties will undergo major changes. Some old varieties will be eliminated and some new varieties will emerge. New information technology will promote new paper varieties. At the same time, the paper industry will also face new challenges brought by consumers' desire to spend less, do more things, and do good things.
At the beginning of the 21st century, the basic trends in the development and development of printing paper varieties will be:
Meet the requirements of multi-color printing;
Improve strength and reduce ration;
Improve the paper's optical performance and surface performance;
Increase the amount of fillers and pigments;
Use a variety of effective chemical additives;
Adapt to the requirements of new printing ink, printing process and printing equipment, with good printability and operating efficiency;
To create conditions for continuously expanding the use of recycled fiber pulp (DIP);
Develop a series of products to achieve a balance between use, quality and production costs.
With regard to the development of new varieties of international printing paper, a series of mechanical pulp printing paper series and chemical wood pulp printing paper series are briefly introduced below.
The new varieties of mechanical pulp printing paper series can be divided into two categories: the first is the improvement, enhancement and development of new types of extended non-coated machinery wood pulp printing paper based on newsprint, and the second is for color A new type of printing machinery, wood pulp printing paper.
1. New varieties of uncoated mechanical pulp printing paper.
After a revolution in printing technology in which relief printing was transformed into offset printing, offset printing and thermosetting inks have become the mainstream of newspaper printing. At the same time, newsprint users no longer care about newsprint ash content below 3% of the quality indicators, but hope that newsprint should be low-quantity, high-intensity, good optical performance and printing performance. Therefore, paper companies have added fillers to newsprint in order to improve the opacity of newsprint paper and the ink repellency of printing inks; and on the surface of newsprint papers, surface treatment is performed to prevent them from falling off during offset printing. In the raw materials, the use of recycled wood pulp has also been minimized with chemical pulp, and a series of new varieties have been developed, such as refined newsprint (IN paper) and advanced newsprint (Super Improved Newsprint, SIN for short). Paper), super calendered paper (SC paper), surface-treated supercalendered paper (ST/SC paper), and pigmented paper (MFP paper).
Supercalendered paper (SC paper) is a non-coated mechanical wood pulp printing paper that was first developed by the Finnish paper industry using mechanical pulp as the main fiber material, adding a considerable number of fillers, and finishing with a supercalender. It can also be said graphically that SC paper is a high-fill, high-ash, high-grade newsprint paper. The SC paper has a basis weight of about 60 g/m 2 . There are three types of SC paper, SC-A paper filler content (20 ~ 30)%, SC-B paper filler content of 15%, SC-C paper without filler.
SC crepe paper is a typical high grade non-coated mechanical wood pulp paper. In the European market, the competition between SC paper and low weight coated paper (LW paper) is very intense. Some Finnish paper companies believe that the performance quality of SC paper can catch up with LWC paper. SC paper is still rare in the Chinese market. Domestically, Fujian Longyan Paper Industry Co., Ltd. invested RMB 6.8 billion to establish a production line that can produce SC paper. This production line was trial-produced in 1998. It produced high-quality newsprint in 1999 and was welcomed after it was put on the market. The plant uses the masson pine as raw material for pulping and is now adjusting its technology to meet the requirements for the production of SC paper.
Refined newsprint (IN paper) and premium newsprint (SIN paper) are premium newsprints with fillers and surface treatments. After this treatment, not only can the optical properties and printing performance of the paper be improved, but also the whiteness of the paper can be improved, overcoming the problem of insufficient whiteness due to the use of recycled pulp.
The surface-treated supercalendered paper (ST/SC paper) was surface treated with a predetermined amount of size press and was finished with soft calendered SC paper. ST/SC paper has good smoothness, gloss, and gloss contrast.
Pigmenting Paper, also called Machine Finished Pigmented Paper (MFP paper for short), is a new type of mechanical pulp printing paper developed in Japan. It is called "Bitokoshi" in the Japanese market. The quantification of MFP paper is (49-54) g/m2, which is a cheap substitute for LWC paper. The amount of fillers and pigments on the surface of MFP paper increases, and printing performance and whiteness improve.
2. A new type of mechanical pulp printing paper coating machine.
New types of coated mechanical pulp printing papers include: Lightweight Coated Paper (LWC), Film Coated Offset Paper (FCO), and Machine Finishing (Machine) -finished Coated Paper (MFC paper for short). These varieties all have good color printing performance, and can be used to print inserts, leaflets, coupons, catalogues, samples, magazines, and Other printed materials, of which LWC paper is particularly popular in the market. The three kinds of papers are described as follows:
Low weight coated paper (LWC paper): In the international market, North America's No. 5 low-quantity coated paper is used as the standard product. The basis weight of LWC paper is (58-61) g/m2, and the coating amount per side does not exceed 7 g/m2. The raw material of LWC paper base paper is still mechanical pulp, but in order to meet the strength requirements of raw paper, there are more bleached sulfate chemical wood pulp. The whiteness, gloss, and smoothness of the LWC paper and the chemical pulp ratio in the base paper are the highest in the mechanical pulp printing paper product line. LWC paper has good opacity and bulk. Some “low-quantity coated paper†in the Chinese market, the raw material of fiber in the base paper is chemical wood pulp and chemical grass pulp, and no or less mechanical wood pulp is used, so all the quality indicators cannot meet the requirements of genuine LWC paper. In the Chinese market, more and more imported LWC papers have been imported, and imports have increased exponentially over the years. China's Yueyang Paper Group Corporation introduced advanced equipment such as alkaline hydrogen peroxide bleaching chemical mechanical pulp and technical equipment, as well as advanced equipment such as size press and soft calendering, to bleach the poplar chemical machinery pulp. Raw materials, and the use of neutral paper technology, produced a qualified low-weight coated paper 65g/m2 (Note, the magazine had a special report). The company's low-quantity coated paper has high smoothness, good surface strength and high gloss. After the trial printing, the paper has uniform ink, good ink absorption, clear printing colors, clear images and good development prospects.
The coating weight of film-coated offset printing paper (FCO paper) is (51-60) g/m2, and the coating amount per side is (6-8) g/m2. The gloss of formed paper is close to the gloss of LWC paper, and the roughness is slightly. Above the roughness of LWC paper, bulk and opacity are better. The paper ash of FCO paper is divided into (10~15)%, and the ash content of raw paper is only (4~5)%. FCO paper base paper has more mechanical wood pulp content and less chemical wood pulp content. Therefore, the production cost of FCO paper is low. Many papermaking companies in North America and Northern Europe have produced FCO papers and believe that FCO papers have good competitiveness and market prospects. In the Chinese paper market, no FCO papers have yet been seen.
In the 1980s, the Finnish paper industry transformed small newsprint machines and developed and produced mechanical finishing coated paper (MFC paper). After 1986, 4 paper machines in Finland and 1 paper machine in Canada were converted to MFC paper. The quantification of MFC paper is not clearly defined and is generally (52-70) g/m2. The roughness of MFC paper is higher, but the whiteness and bulk are better. MFC paper is not suitable for rotogravure printing, but performs well when subjected to thermosetting offset printing. MFC paper is a low-quantity, high-fill, coated printing paper produced by blade coating. The base paper must have high strength, so it needs more chemical wood pulp, and the production cost is also higher.
At the turn of the century, digital information technology has received unprecedented attention, and the printing industry is no exception. With the continuous advancement of science and technology, new types of paper serving digital information technology are emerging. These newly developed paper types can be collectively referred to as digital printing paper.
Digital printing paper is almost always made from bleached kraft chemical wood pulp with a high degree of brightness, with a uniform blue-white color. For the production of digital printing paper, bleached conifer kraft wood pulp and bleached broad-leaved tree kraft wood pulp are commonly used to produce a paper sheet with good strength, opacity, bulk, stiffness and whiteness, and uniform organization. , Paper smooth, clean, no fiber bundles, spots and dust, lint-free powder, good optical properties and printing performance. In the manufacturing process, it is generally necessary to add certain fillers, such as precipitated calcium carbonate.
Digital printing paper uses neutral paper and neutral sizing, and applies a variety of chemical additives, such as retention aids, reinforcing agents, lubricants. It has been reported that the use of different sizing agents for non-coated ink-jet printing papers can have different effects, and therefore it is necessary to rationally select sizing agents for production. Retention aids are another common adjuvant in the production of digital printing paper. The use of retention aids tends to affect the formation of the paper. This problem should be taken into consideration when using a particulate retention aid. For papermaking using recycled fiber pulp, in order to compensate for insufficient fiber strength, starch or synthetic resin reinforcing agents may be used to increase the strength of the paper.
Digital printing paper is mostly small-size paper, and has a high requirement for the fiber binding strength, cleanliness, and two-sided difference of the paper surface. In order to prevent the paper from falling into powder and entraining burrs, shards, and confetti, the cutting blade must be sharp and sharp. In order to increase the paper fiber binding force, a predetermined amount of size press can be used for surface treatment. The paper machine should use an advanced top former to minimize the difference between the two sides of the paper sheet. Soft calendering should also be used to obtain good smoothness.
At present, some domestic joint venture papermaking companies, such as Kunshan Yalong Paper Products Co., Ltd. and Changshu Asia Pacific Paper Co., Ltd., have started to use advanced technology and equipment to produce digital printing papers such as laser printing paper and ink jet printing paper. These enterprises will It has become the main force in the production of digital printing paper in the early new century in China. It is also known that some state-owned papermaking industries are also brewing technological transformation projects for the production of digital printing paper. I hope that the state-owned enterprises in the paper industry in China can catch up and take a place in the digital printing paper market as soon as possible. Looking forward to the 21st century, papermaking and printing originating in China, with the joint efforts of a new generation of Chinese printing industry and papermaking industry colleagues, will surely re-create brilliant achievements. Pan Xiwu