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Fibers in paper
- 1. FIBERS IN PAPER 2020247002 Jeon Hyeonjin 1
- 2. Topic Selection Reason • Paper physical properties are largely related to base paper, that is, fiber. • The surface properties of the paper can be adjusted through secondary processing such as coating. • But, It is impossible to completely hide the defects of the base paper by coating. • Therefore, it is important to select a base paper for proper properties. 2
- 3. Index • What is Paper? • Pulp • Refining • Fines and vessel element • Priority of important properties to paper type 3
- 4. What is Paper? • Paper : A product made by combining a large number of small fibers. • A wide variety of paper is produced according to its use. - Definition of paper 4
- 5. What is Paper? - Various fibers Average fiber length, fiber width, and length ratio by fiber type. Length(㎜) Width(㎛) Ratio (Length/Width) Wood Softwood 4.0 40 100 hardwood 2.0 22 90 Herbaceous plant Straw 0.5 9 60 Esparto 1.1 10 110 Reeds Sugar cane 1.7 20 80 Bamboo 2.8 15 180 Seed hair fiber Cotton 30 20 1,500 Linter 20 20 1,000 5 Cho HJ, Pulp and Paper Engineering, SUNJIN, 1997
- 6. What is Paper? • It is the most abundant resource. • It has high yield and economy. • Stable supply is possible. - Why wood fibers are used for papermaking 6
- 7. Pulp • Pulp : Fiber raw material for papermaking. • There are various types of pulp. - Natural pulp - dissolving pulp - Cotton-shaped pulp, etc. - What is pulp? 7
- 8. Pulp • Wood Pulp - Softwood pulp - Hardwood pulp • DIP (Deinking pulp) or Recycled Pulp • Nonwood Pulp - Straw pulp - Bagassa pulp - Bamboo pulp - Rag pulp - Bast Fiber pulp - Pulp classification by raw material 8
- 9. Pulp - Softwood and hardwood cells 9
- 10. Pulp - Softwood and hardwood cells 10 https://www.slideshare.net/Peeke/fiber-and-pulp-characteristics-for-papermaking-51877512
- 11. Pulp Softwood pulp Hardwood pulp Fiber length Long Short Fiber strength Strong Weak Main property when make paper Good strength property Bulky and good smoothness Usage Wrapping paper Printing paper, Tissues - Difference between softwood pulp and hardwood pulp 11
- 12. Pulp • Mechanical Pulp - Ground wood Pulp (GP) - Thermo Mechanical Pulp (TMP) • Semichmical Pulp - Neutral Sulfite Semichemical Pulp (NSSP) - high-yield kraft • Chmical Pulp - Kraft pulp (KP) - sulfite pulp (SP) - Pulp classification by pulping process 12
- 13. Pulp - Mechanical Pulp and Chmical Pulp. Mechanical Pulp Chmical Pulp Pulp made by mechanical decomposition Chemically de-lignined pulp. High yield Low yield Chemical composition is similar to wood High brightness and stability 13
- 14. Pulp • Pulp, the raw material of paper, determines the paper properties. • In The pulp properties, There are fundamental properties and functional properties. • Fundamental properties - Fiber length - Fiber strength - Coarseness - Flexibility - Chemical composition, etc. • Functional properties - Colour or Brightness - Fiber viscosity - Dehydration - Wet strength, etc. - Pulp fiber properties 14
- 15. Refining • The rotor rotates to apply shear stress to the fibers, changing the properties of the fibers. • Internal fibrillation and external fibrillation proceed to promote the swelling of fibers and make them soft and smooth. - What is refining? 15
- 16. Refining • Shortened by cutting action • Increased specific surface area through fibrillation • Increased fiber flexibility • Removal of the primary wall • Increased swelling properties of fibers - The effect of refining Internal fibrillation External fibrillation 16
- 17. Refining - The result of refining 17
- 18. Refining • Important structural features (length, diameter, coarseness). - The effect of fiber structure on paper properties 18
- 19. Refining • Fibrillation -> Specific surface area increase -> Hydrogen bond increase - Fiber bonding 19 https://www.slideshare.net/Peeke/fiber-and-pulp-characteristics-for-papermaking-51877512
- 20. Refining • Flexible fiber → high contact area → increased hydrogen bonding - Fiber flexibility 20 https://www.slideshare.net/Peeke/fiber-and-pulp-characteristics-for-papermaking-51877512
- 21. Refining - Idealized fiber structures 21 Cho HJ, Pulp and Paper Engineering, SUNJIN, 1997
- 22. Refining • Thickness - The thicker it is, the less refining • Opacity - Thick fiber and low contact area, the more opaque • Stiffness - proportional to the strength of the fiber • Porosity - The thicker fiber and the narrower the contact surface, the higher the porosity. - Paper Properties Affected by Fiber 22
- 23. Fines and vessel element • Primary fine • Secondary fines - Primary fines and Secondary fines 23 Martin A. Hubbe, 2002, Fines Management for Increased Paper Machine Productivity, fig
- 24. Fines and vessel element • Short fiber → Less bonding between several fibers → Weak paper properties • Small contact surface area → Weak bonding → Decreased print ability, vessel picking - The influence of fines Vessel pick “Picked” vessel 24 https://vdocuments.site/hardwood-vessel-picking.html
- 25. Priority of important properties to paper type • Printing, writing paper - Optical properties (brightness, opacity, gloss) - Surface characteristics (uniformity, smoothness, water absorption) - Strength (surface strength, tensile strength, stiffness, tear strength) • Wrapping paper - Strength (stiffness, toughness) - Barrier, porosity - Hydrophobic - Optical properties (whiteness, gloss) • Sanitary paper - Absorption - Softness (low stiffness) - Strength (Wet-web strength, strain, dry strength (necessary for processing)) - Whiteness - The influence of fines 25
Editor's Notes
- 우선 주제 선정 이유부터 말씀드리겠습니다. Firstl, I will tell you the reason for the topic selection. I focused on the fiber. Paper physical properties are largely related to base paper, that is, fiber. The surface properties of the paper can be adjusted through secondary processing such as coating. But, It is impossible to completely hide the defects of the base paper by coating. Therefore, it is important to select a base paper for proper properties.
- 목차, 순서는 다음과 같습니다. The table of contents is as follows.
- 우선 우리는 종이가 무었인지 알아야 합니다. First, we need to know what paper is. 종이란 Paper : A product made by combining a large number of small fibers. A wide variety of paper is produced according to its use. Like 코리게이티드 보드, color paper, 티슈 골판지나 색상지 티슈 와 같이..
- 종이에 사용되는 섬유는 다양하다. There are a variety of fibers used in paper. 나무뿐만 아니라 짚이나 솜도 종이의 원료가 될 수 있다. Not only wood, but also straw or cotton can be a raw material for paper.
- 그렇다면 왜 목재섬유를 제지용으로 사용하는가? then, why are wood fibers used for papermaking? 왜냐하면 목재섬유는 -It is the most abundant resource. -It has high yield and economy. -Stable supply is possible.
- 다음은 펄프입니다. Next is the pulp. 펄프는 종이의 원료로, 다양한 종류의 펄프가 있다. Pulp is a raw material for paper, and there are various types of pulp.
- Pulp can be classified according to the raw material. There are Wood Pulp, Nonwood Pulp, Recycled Pulp
- 대표적으로 목질펄프에는 침엽수 펄프와 활엽수 펄프가 있다. Representatively, wood pulp includes softwood pulp and hardwood pulp. 나무는 여러 세포로 구성되는데, 침엽수와 활엽수의 세포 종류는 다르다. Trees are composed of many cells, and the cell types of softwoods and hardwoods are different.
- 또한 수종에 따라서도 세포의 구성과 크기가 다르다. Also, the cell composition and size are different depending on the species. There is a Vessel element in hardwoods, but not in softwoods.
- 침엽수 펄프와 활엽수 펄프를 비교 할 때. When comparing softwood pulp and hardwood pulp 일반적으로 섬유의 길이는 침엽수 펄프가 더 길고 generally, the fiber length is longer in softwood pulp, 섬유의 강도 또한 침엽수 펄프가 더 강하다. The strength of the fiber is also stronger in softwood pulp. 그래서 침엽수펄프는 강도적 특성이 좋아 포장지에 주로 쓰인다. So, softwood pulp is mainly used in packaging paper because of its strength property.
- Other classification methods can be pulping process. There are Mechanical Pulp, Semichmical Pulp and Chmical Pulp.
- 대표적으로 목질펄프에는 침엽수 펄프와 활엽수 펄프가 있다. Representatively, Mechanical Pulp and Chmical Pulp. 기계펄프는 물리적으로 만들어져 섬유가 파괴되고 거칠다. In contrast, chemical pulp tends to be intact. But the yield is low because there is no rignin.
- 종이의 원료인 펄프는 그 특성에 따라 종이의 특성을 좌우한다. Pulp, the raw material of paper, determines the paper properties. 펄프의 특성에는 근원적 특성과 기능적 특성이 있다. In The pulp properties, There are fundamental properties and functional properties.
- 다음은 리파이닝입니다. 리파이닝이란 무었일까? 리파이닝은- 로터가 회전하여 섬유에 전단 응력을 가해 섬유의 특성을 변화시킴 The rotor rotates to apply shear stress to the fibers, changing the properties of the fibers. 내부 피브릴화 및 외부 피브릴화가 진행되어 섬유의 팽윤을 촉진시키고 부드럽고 유현하게 만든다. Internal fibrillation and external fibrillation proceed to promote the swelling of fibers and make them soft and smooth.
- 리파이닝의 효과로 by the refining The fibers are shorten and Removal of the primary wall. Slao Increased specific surface area through fibrillation And Increased fiber flexibility.
- 리파이닝의 결과로 The result of refining. We can see fibrills around the fibers.
- 앞서 말한 것처럼 섬유의 구조적 특징은 종이의 특성에 영향을 미친다. As I mentioned, the structural features of the fibers affect the paper properties. 리파이닝을 통해 우리는 이러한 주요 특징들을 다룰 수 있다. Through refining we can treat these features.
- Fibrillation이 되면, 피브릴로 인하여 표면적이 넓어지게 된다. When fibrillation occurs, the surface area becomes wider due to fibrils. 그로인해 접촉면적이 넓어지게 되고, 충분한 수소결합이 일어날 수 있다. As a result, the contact area becomes wider, and sufficient hydrogen bonding can occur.
- 유연성도 같은 기작이다. Flexibility is the same principle. 접촉면적이 넓어지게 되고, 충분한 수소결합이 일어날 수 있다. the contact area becomes wider, and sufficient hydrogen bonding can occur.
- 이 그림은 가상적인 두 가지 형태의 섬유 구조를 나타낸다. This figure shows two hypothetical types of Idealized fiber structures. 두 그림은 섬유의 수와 접촉점의 수는 같으나 The two figures show the same number of fibers and contact points 접촉 면적간 결합 가능부위는 세포벽이 얇은 B가 더 크다. But B, which has a thin cell wall, is larger in the bonding area between the contact areas.
- 섬유에 의해 영향을 받는 종이의 물성적 특성들에는 Paper Properties Affected by Fiber, There is Thickness, Opacity, Stiffness… and so on..
- 펄프에는 이상적인 크기의 섬유외에도 아주 작은 섬유들도 존재한다. In addition to fibers of ideal size, there are also very small fibers in the pulp. 우리는 이것을 미세분이라 부른다. We call this fine. 미세분에는 1차 미세분과 2차 미세분으로 구분 할 수 있다. Fines can be classified to primary fines and secondary fines. 1차 미세분은 원래 크기가 작은 세포들이며 대표적으로는 도관요소나 유세포이다. The primary fines are cells of small original size and are typically parenchyma cells or vessel elements. 2차 미세분은 공정 과정에서 발생한 짧은섬유들로 리파이닝이나 비팅에 의해 짧게 잘린 섬유들이다. Secondary fines are short fibers generated in the process of being cut short by refining or beating.
- 미세분은 제지공정과 제품에 나쁜 영향을 끼친다. Fines have a bad influence on the paper making process and products. 비표면적이 높아 스톡의 농도를 높이고 첨가제의 효율을 떨어뜨린다. The high specific surface area increases stock concentration and decreases the efficiency of additives. 또한 섬유가 짧아 여러 섬유간 결합이 적어 종이의 물성적 특성을 약화시킨다. In addition, as the fibers are short, there are few bonds between several fibers, which weakens the physical properties of paper. 그리고 결합면적이 좁아 결합이 약해져서 인쇄적성이 나빠진다. And the bonding area is narrow, the bonding is weakened, resulting in poor printability.
- 마지막으로 종이별 중요 특성 우선순위를 알아보자. In last, let's look at the priority of important properties to paper types. 종이의 사용목적에 따라서 필요로 하는 특성은 다를 것이다. Purpose of the paper, the required properties will be different. 예를들어 인쇄용지의 경우 픽업 강도가 좋아야 할 것이고 In the case of printing paper, the pickup strength should be good 포장지는 외부 충격에 버텨야 하므로 높은 강직성을 요구한다. the wrapping paper must endure external impact, it requires high stiffness. 티슈와 같은 위생용지는 습지필강도, 유연성, 흡습성이 좋아야 한다. such as tissue should have good Wet-Web Strength, flexibility, and good absorbent 우리는 다양한 목적에 따라 섬유를 어떻게 처리 할지 알아야 할 것이다. We'll need to know how to handle the fiber for its purpose.