Manufacturing method of in-machine coating art paper

Abstract

The invention discloses a manufacturing method of in-machine coating art paper, which comprises the following operation steps: S1, proportioning: respectively pulping softwood pulp, hardwood pulp and cotton pulp, and mixing according to a certain weight ratio to form mixed pulp; s2, auxiliary materials are added into the mixed pulp, then wet paper sheet papermaking, pre-drying, in-machine coating with a coating, post-drying and calendaring are sequentially conducted, and finally the art paper with the quality meeting the requirement is prepared. According to the manufacturing method of the in-machine coating art paper, the manufactured art paper is fine and smooth in product surface, uniform in coating and rich and unique in texture and texture, the ink absorption performance is good after color printing, images are clear and vivid, the color is bright and full, the layering sense is high, and the color reducibility is good.

Description

Technical Field

[0001] The present invention relates to the field of papermaking methods, and particularly to a method for manufacturing in-machine coated art paper. Background Art

[0002] Cultural printing paper occupies an important position in China's paper products and has always been a very important part of China's paper industry. Traditional cultural printing paper can generally be classified into newsprint, writing paper, offset paper, lightly coated paper, coated paper and other varieties according to product quality.

[0003] Art paper is a new type of cultural printing paper. Art paper is made from specific raw materials through specific process technologies. It is a special paper with rich and unique textures on the paper surface and has certain artistic aesthetic value. It is significantly different from traditional ordinary printing papers (such as coated paper, offset paper, lightly coated paper, newsprint, etc.) and is widely used in products such as fine packaging, picture albums, book covers, binding, cards, etc.

[0004] Art paper has many special features in terms of paper structure and performance. The production and quality requirements of art paper are quite different from those of ordinary printing paper. In terms of pulp, art paper has relatively high quality requirements for pulp, mostly pure wood pulp with more long fibers, and some also contain cotton fiber components. After being formed by such pulp, the paper has good strength, toughness, good stiffness and elasticity of the paper, and relatively bright colors. In addition, art paper generally requires special paper processing equipment and process technologies to ensure that the manufactured finished paper has unique and rich colors and unique textures, good ink absorption performance after printing, high color saturation, and can avoid phenomena such as back sticking and print powdering caused by slow ink drying. Specifically speaking, the important features of art paper lie in its color, texture and texture.

[0005] With the development of the times and the progress of technology, people's increasing demand for personalized design aesthetics, design products mainly based on paper pay more and more attention to the creative use of paper. Traditional coated paper, lightly coated paper and offset paper have limitations in both variety and material performance. Art paper caters to the trend of modern design aesthetics with its diverse varieties, fast update speed and diversified texture and texture styles, and is widely developed and applied in multiple fields such as commodity packaging, books, clothing, and home design.

[0006] Therefore, how to provide a manufacturing method that can manufacture art paper with better quality is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a method for manufacturing in-machine coated art paper. The art paper manufactured by the method has a delicate product surface, uniform coating, rich and unique texture and grain, good ink absorption performance after color printing, clear and realistic images, bright and full colors, strong layering, and good color reproduction.

[0008] The technical solution provided by the present invention is as follows: A method for manufacturing in-machine coated art paper comprises the following steps: S1. Mixing ingredients: beating coniferous wood pulp, hardwood wood pulp and cotton pulp separately and mixing them in a certain weight ratio to form a mixed pulp; S2. Add auxiliary materials into the mixed slurry, and then go through wet paper sheet making, pre-drying, in-machine coating with coating, post-drying, and calendering in sequence to finally produce art paper with quality that meets the requirements. The pre-drying dries the wet paper sheet with a dryness of about 50% to a dryness of about 95%; the post-drying dries the wet paper sheet with a dryness of about 20% to a dryness of about 93%.

[0009] Preferably, in step S1, the weight ratio of pulp is coniferous wood pulp: hardwood wood pulp: cotton pulp = 15-25: 55-70: 10-20.

[0010] Preferably, in step S1, the freeness of the pulp after beating is: 318-358 ml for coniferous wood pulp, 355-395 ml for hardwood pulp, and 210-250 ml for cotton pulp.

[0011] Preferably, the auxiliary material in step S2 is prepared by mixing a sizing agent alkyl ketene dimer, a filler, a cationic starch, a retention aid polyacrylamide and modified diatomaceous earth in a certain weight ratio.

[0012] Preferably, the amount (weight percentage) of auxiliary materials to the absolute dry pulp in step S2 is: sizing agent alkyl ketene dimer 0.24-0.28%, filler 7-11%, cationic starch 0.9-1.1%, retention aid polyacrylamide 0.04-0.06%, modified diatomaceous earth 0.2-0.3%.

[0013] Preferably, the coating in step S2 comprises the following components by weight: 10 to 30 parts of heavy calcium carbonate, 70 to 90 parts of kaolin, 10 to 15 parts of styrene-butadiene latex, 2 to 4 parts of surface enhancer, 0.2 to 0.6 parts of rheology modifier, 0.2 to 0.6 parts of CMC, 0.5 to 1.0 parts of lubricant, 0.5 to 1.0 parts of water repellent, and an appropriate amount of water.

[0014] Preferably, the solid content of the coating in step S2 is 60-65%.

[0015] Preferably, the coating conditions in step S2 are as follows: the pressure in the drive-side nip / the pressure in the operator-side nip is 17 - 20 / 17 - 20 kN / m, the pressure applied to the upper roller metering rod / the pressure applied to the lower roller metering rod is 0.8 - 1.5 / 0.8 - 1.5 bar, and the coating weight is 20 - 24 g / m 2 ; the set value of the paper tension in the sizing section is 180 - 220 N / m.

[0016] Preferably, the calendering conditions in step S2 are as follows: the calender uses a 1+7 nip mode, the temperature of the hot roller in the first nip is 45 - 55 °C, the linear pressure is 12 - 18 kN / m, the temperature of the hot roller in the seventh nip is 45 - 55 °C, and the linear pressure is 12 - 18 kN / m.

[0017] Preferably, the basis weight of the art paper prepared in step S2 is 80 - 100 g / m 2 , the moisture content is 5.0 - 7.0%, the whiteness is ISO 83 - 85%, the opacity is 90 - 92%, the bulk is 1.15 - 1.19 cm 3 / g, the surface absorption weight is 25 - 30 g / m 2 , the longitudinal breaking length is ≥5500 m, the smoothness is 50 - 70 s, and the printing surface strength is ≥1.0 m / s.

[0018] The present invention has the following advantages over the prior art: The art paper produced by the manufacturing method of the present invention has a delicate surface, uniform coating, rich and unique texture, good ink absorption performance, and high artistic aesthetic value. The manufacturing method of the in-machine coated art paper of the present invention involves in-machine coating with a special coating formulation and finishing the surface of the base paper using a super soft calender with a special elastic roll. The calender nip of an ordinary paper machine calender consists of two relatively hard chilled cast iron rolls. For a paper sheet with an uneven surface, the roll surface only contacts the raised parts of the surface, and the low parts are not contacted. The compactness of the contacted parts increases, and bright spots are formed when pressure is increased, resulting in uneven surface characteristics. The calender nip of the soft calender used in the present invention consists of a chilled cast iron roll that can be heated and temperature-adjusted and a soft roll with a controllable width and an elastic material-coated roll shell. The prominent advantage of the soft roll surface is that it produces a wider and softer calender nip. The paper web stays in the calender nip for a long time, forming a surface contact in the calender nip. The pressure applied to the paper web per unit area is small, and the surface of the paper web is treated more gently. The unevenness of the paper surface is absorbed by the deformation of the elastic roll, so that the paper surface is completely in contact with the roll surface. After calendering, the compactness of the paper sheet changes gently and continuously. Since the elastic roll covering material has elasticity, during the pressurization process, it has a greater adaptability to the unevenness of the paper basis weight. Therefore, a very uniform fine smoothness and texture can be obtained throughout the paper surface. This finishing method not only effectively improves the delicate performance of the paper surface, but also endows the paper surface with rich and unique texture. This texture is neither as cold and slippery as that of some high-grade papers, nor as rough and rigid as that of ordinary papers, but a texture and sense of touch close to human skin. The art paper produced by the manufacturing method of the present invention has clear, vivid, bright, full-color, strong layering, and good color reproducibility after color printing. It is widely used in the printing of high-grade books and periodicals, color pictorials, color albums, binding, cards, and fine magazines due to its exquisite printing, and is deeply welcomed by customers with broad market prospects. Detailed implementation manners

[0019] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] Embodiment 1: The coniferous pulp (318 - 358 ml), broadleaf pulp (355 - 395 ml), and cotton pulp (210 - 250) with the freeness meeting the requirements after beating are mixed in a weight ratio of 25%:65%:10%; then 7% calcium carbonate is added as a filler, and it is sent into a first-stage four-section conical refiner through a pulp pump for purification and slag removal, and then enters a degassing tank for degassing treatment; then it enters a pressure screen for screening treatment (0.6 kg / ton of paper of cationic PAM, 10 kg / ton of paper of cationic starch, and 2.5 kg / ton of paper of sizing agent alkyl ketene dimer are added at the inlet of the pressure screen, and 2.2 kg / ton of paper of modified diatomaceous earth is added at the outlet of the pressure screen); then it is sent into a headbox to form a web, the web-forming flow rate is adjusted, and the basis weight of the paper sheet before sizing is controlled at about 60 g / m 2 ; after the wet paper sheet exits the forming section, it enters the press section for five-roll three-pressure-zone combined pressing, and after pressing to a dryness of ≥39%, it enters the pre-drying section; the surface temperature of the dryer cylinder is controlled at 90 - 130 °C to dry the paper sheet until the dryness of the paper sheet is ≥95%; it enters a sizing press for coating surface treatment, and the coating, by weight, is: 30 parts of GCC, 70 parts of kaolin, 10 parts of latex, 4 parts of surface strengthening agent, 0.2 part of CMC, 0.3 part of rheology modifier, 0.8 part of lubricant, 0.8 part of water repellent, and an appropriate amount of water, and the solid content of the coating is 64%; the coating is stirred evenly, and a metering rod-type surface sizing machine is used to coat the reverse side of the paper sheet entering from the pre-drying section, and the coating amount is controlled at 20 g / m 2 , and then it exits the surface sizing machine and enters post-drying treatment; the wet paper sheet that has undergone surface sizing deep treatment is continuously post-dried, the dryer cylinder temperature is controlled at 40 - 130 °C, and the dryness of the paper sheet exiting the post-drying section is ≥93%; the paper sheet entering from the post-drying section enters the calendering zone for calendering treatment, and a 1 + 7 calendering zone is selected for the calender, the temperature of the hot roll is 50 °C, and the line pressure is 10 kN / m and 15 kN / m respectively; after calendering, the paper is wound up, and an art paper with a basis weight of 80 g / m 2 , a whiteness of 84% ISO can be obtained. The bulk of this product is 1.18 cm 3 / g, the smoothness is 65 s, the surface of the product is delicate, the coating is uniform, it has a rich and unique texture, good ink absorption performance, accurate overprinting, clear printed patterns, full colors, good printing effect, and high artistic aesthetic value.

[0021] Example 2: The needle wood pulp (318 - 358 ml), broad leaf wood pulp (355 - 395 ml), and cotton pulp (210 - 250 ml) with the freeness meeting the requirements after beating are mixed according to the weight ratio of 20%:65%:15%; then 9% calcium carbonate is added as a filler, and it is sent into a first-stage four-stage conical slag remover by a pulp pumping pump for purification and slag removal, and then enters a degassing tank for degassing treatment; after that, it enters a pressure screen for screening treatment (0.6 kg / ton of paper of cationic PAM, 10 kg / ton of paper of cationic starch, and 2.5 kg / ton of paper of sizing agent alkyl ketene dimer are added at the inlet of the pressure screen, and 2.2 kg / ton of paper of modified diatomaceous earth is added at the outlet of the pressure screen); then it is sent into a headbox to form a web, the web-forming flow rate is adjusted, and the basis weight of the paper sheet before sizing is controlled at about 68 g / m²; after the wet paper sheet exits the forming section, it enters the press section for five-roll three-pressure zone combined pressing, and after pressing to a dryness of ≥39%, it enters the pre-drying section; the surface temperature of the dryer cylinder is controlled at 90 - 130 °C to dry the paper sheet until the dryness of the paper sheet is ≥95%; it enters a size press for coating surface treatment, and the coating is composed of, by weight: 30 parts of GCC, 70 parts of kaolin, 10 parts of latex, 4 parts of surface strengthening agent, 0.2 part of CMC, 0.3 part of rheology modifier, 0.8 part of lubricant, 0.8 part of water repellent, and an appropriate amount of water, and the solid content of the coating is 64%; the coating is stirred evenly, and a metering rod type surface sizing machine is used to coat the reverse side of the paper sheet entering from the pre-drying section, and the coating amount is controlled at 22 g / m 2 , then it exits the surface sizing machine and enters post-drying treatment; the wet paper sheet that has undergone surface sizing deep treatment is continuously post-dried, the dryer cylinder temperature is controlled at 40 - 130 °C, and the dryness of the paper sheet exiting the post-drying section is ≥93%; the paper sheet entering from the post-drying section enters a calendering zone for calendering treatment, a 1 + 7 calendering zone is selected for the calender, the temperature of the hot roll is 50 °C, and the linear pressure is 10 kN / m and 15 kN / m respectively; after calendering, the paper is wound up, and then an art paper with a basis weight of 90 g / m 2 and a whiteness of 84% ISO can be obtained. The bulk of this product is 1.17 m 3 / g, the smoothness is 60 s, the surface of the product is delicate, the coating is uniform, it has a rich and unique texture, good ink absorption performance, accurate overprinting, clear printed patterns, full colors, good printing effect, and high artistic aesthetic value.

[0022] Example 3: The coniferous pulp (318 - 358 ml), broadleaf pulp (355 - 395 ml), and cotton pulp (210 - 250 ml) with the freeness meeting the requirements after beating are proportioned according to the weight ratio of 15%:65%:20%; then 11% calcium carbonate is added as a filler, and it is sent into a first-stage four-stage conical slag remover by a pulp pumping pump for purification and slag removal, and then enters a degassing tank for degassing treatment; after that, it enters a pressure screen for screening treatment (0.6 kg of cationic PAM per ton of paper, 10 kg of cationic starch per ton of paper, and 2.5 kg of sizing agent alkyl ketene dimer are added at the inlet of the pressure screen, and 2.2 kg of modified diatomaceous earth is added at the outlet of the pressure screen); then it is sent into a headbox to form a web, the web-forming flow rate is adjusted, and the basis weight of the paper sheet before sizing is controlled at about 76 g / m 2 ; after the wet paper sheet exits the forming section, it enters the press section for five-roll three-pressure-zone combined pressing, and after pressing to a dryness of ≥39%, it enters the pre-drying section; the surface temperature of the dryer cylinder is controlled at 90 - 130 °C to dry the paper sheet until the dryness of the paper sheet is ≥95%; it enters a sizing press for coating surface treatment, and the coating, by weight, is: 30 parts of GCC, 70 parts of kaolin, 14 parts of latex, 2 parts of surface strengthening agent, 0.2 part of CMC, 0.3 part of rheology modifier, 0.8 part of lubricant, 0.8 part of water repellent, and an appropriate amount of water, and the solid content of the coating is 64%; the coating is stirred evenly, and a metering rod-type surface sizing machine is used to coat the reverse side of the paper sheet entering from the pre-drying section, and the coating amount is controlled at 24 g / m 2 , and then it exits the surface sizing machine and enters the post-drying treatment; the wet paper sheet that has undergone surface sizing deep treatment is continuously post-dried, the dryer cylinder temperature is controlled at 40 - 130 °C, and the dryness of the paper sheet exiting the post-drying section is ≥93%; the paper sheet entering from the post-drying section enters the calendering zone for calendering treatment, and a 1 + 7 calendering zone is selected for the calender, the temperature of the hot roll is 50 °C, and the line pressure is 10 kN / m and 15 kN / m respectively; after calendering, the paper is wound up, and then an art paper with a basis weight of 100 g / m 2 , a whiteness of 84% ISO can be obtained. The bulk of this product is 1.16 cm 3 / g, the smoothness is 55 s, the surface of the product is delicate, the coating is uniform, it has a rich and unique texture and pattern, has good ink absorption performance, accurate overprinting, clear printed patterns, full colors, good printing effect, and has a high artistic aesthetic value.

[0023] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A manufacturing method of in-machine coated art paper, characterized in that, It includes the following operation steps: S1. Ingredients preparation: Softwood pulp, hardwood pulp and cotton pulp are beaten respectively and then mixed according to a certain weight ratio to form a mixed pulp; S2. Add auxiliary materials to the mixed pulp, and then successively go through wet paper sheet forming, pre-drying, in-machine coating with coating material, post-drying, and calendering to finally obtain art paper with qualified quality.

2. The manufacturing method of the in-machine coated art paper according to claim 1, characterized in that, In the step S1, the weight ratio of the pulp is softwood pulp∶hardwood pulp∶cotton pulp = 15 - 25∶55 - 70∶10 - 20.

3. The manufacturing method of the in-machine coated art paper according to claim 1, characterized in that, In the step S1, the freeness of the pulp after beating is: for softwood pulp, 318 - 358 ml; for hardwood pulp, 355 - 395 ml; for cotton pulp, 210 - 250 ml.

4. The manufacturing method of the in-machine coated art paper according to any one of claims 1-3, characterized in that, In the step S2, the auxiliary materials are prepared by mixing sizing agent alkyl ketene dimer, filler, cationic starch, retention aid polyacrylamide and modified diatomite according to a certain weight ratio.

5. The manufacturing method of the in-machine coated art paper according to claim 4, characterized in that, In the step S2, the dosage of the auxiliary materials based on the absolutely dry pulp (weight percentage) is: sizing agent alkyl ketene dimer 0.24 - 0.28%, filler 7 - 11%, cationic starch 0.9 - 1.1%, retention aid polyacrylamide 0.04 - 0.06%, modified diatomite 0.2 - 0.3%.

6. The manufacturing method of the in-machine coated art paper according to any one of claims 1-3, characterized in that In the step S2, the coating material includes the following components by weight: 10 - 30 parts of heavy calcium carbonate, 70 - 90 parts of kaolin, 10 - 15 parts of styrene-butadiene latex, 2 - 4 parts of surface strengthening agent, 0.2 - 0.6 part of rheology improver, 0.2 - 0.6 part of CMC, 0.5 - 1.0 part of lubricant, 0.5 - 1.0 part of water repellent, and appropriate amount of water.

7. The manufacturing method of the in-machine coated art paper according to claim 6, characterized in that, In the step S2, the solid content of the coating material is 60 - 65%.

8. The manufacturing method of the in-machine coated art paper according to any one of claims 1-3, characterized in that, The coating conditions in the step S2 are as follows: the pressure in the drive-side nip / the pressure in the operator-side nip is 17 - 20 / 17 - 20 kN / m, the pressure applied to the upper roller metering bar / the pressure applied to the lower roller metering bar is 0.8 - 1.5 / 0.8 - 1.5 bar, and the coating amount is 20 - 24 g / m 2 ; the set value of the paper tension in the sizing section is 180 - 220 N / m.

9. The manufacturing method of the in-machine coated art paper according to any one of claims 1-3, characterized in that The calendering conditions in the step S2 are: the calender uses a 1 + 7 nip mode, the hot roll temperature in the first nip is 45 - 55°C, the linear pressure is 12 - 18 kN / m, the hot roll temperature in the seventh nip is 45 - 55°C, and the linear pressure is 12 - 18 kN / m.

10. The manufacturing method of the in-machine coated art paper according to any one of claims 1-3, characterized in that, The basis weight of the art paper prepared in step S2 is 80 to 100 g / m 2 , the moisture content is 5.0 to 7.0%, the whiteness is ISO 83 to 85%, the opacity is 90 to 92%, and the bulk is 1.15 to 1.19 cm 3 / g, the surface absorbency weight is 25 to 30 g / m 2 , the longitudinal breaking length is ≥ 5500 m, the smoothness is 50 to 70 s, and the printing surface strength is ≥ 1.0 m / s.