PAPERmaking! Vol8 Nr2 2022

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‡Žƒ–‹‘•Š‹’„‡–™‡‡™‡––ƒ„‹Ž‹–› ‘ˆ’—Ž’Ƥ„‡”•ƒ†–‡•‹Ž‡•–”‡‰–Š



‘ˆ’ƒ’‡”†—”‹‰”‡ › Ž‹‰ ƒ‹Žƒ ‹ ͷǡͺ * ǡ›‘–ƒ‘•‡ ͸ ǡ‘„—•Š‹‰‡ƒ†ƒ ͹ Ƭƒƒ›—‹ƒ›ƒƒ ͸ *

Š‡™‡––ƒ„‹Ž‹–›‘ˆ–Š‡’ƒ’‡”•—”ˆƒ ‡‹•‰”‡ƒ–Ž›ƒơ‡ –‡†„›–Š‡™‡––ƒ„‹Ž‹–›‘ˆ–Š‡’—Ž’Ƥ„‡”•Ǥ‡ ‘†— –‡†–Š‹••–—†›‹‘”†‡”–‘—†‡”•–ƒ†–Š‡”‡Žƒ–‹‘•Š‹’„‡–™‡‡–Š‡™‡––ƒ„‹Ž‹–›‘ˆƒ•‹‰Ž‡Ƥ„‡” ‘ˆ”‡ › Ž‡†’—Ž’ƒ†–Š‡•–”‡‰–Š‘ˆ”‡ › Ž‡†’ƒ’‡”ǡƒ•™‡ŽŽƒ•–Š‡‹–‡”ǦƤ„‡”„‘†‹‰•–”‡‰–ŠǤŠ‡ ‘–ƒ –ƒ‰Ž‡™ƒ•†‡–‡”‹‡†ˆ”‘ƒ•‡”‹‡•‘ˆ’Š‘–‘‰”ƒ’Š•‘ˆ–Š‡’—Ž’Ƥ„‡”ƒ†–Š‡™ƒ–‡”•‹ŽŠ‘—‡––‡• ƒ––Š‡’‘‹–‘ˆ ‘–ƒ –ǤŠ‡ ‘–ƒ –Ž‹‡ƒ†’”‘ƤŽ‡Š‹•–‘”›™‡”‡ ‘–‹—‘—•Ž›’Š‘–‘‰”ƒ’Š‡†‹‡˜‡”› ͷ•ƒˆ–‡”–Š‡‹‹–‹ƒŽ ‘–ƒ –ǤŠ‡”‡ › Ž‡†•‘ˆ–™‘‘†”ƒˆ–’—Ž’Ƥ„‡”•™‡”‡ Ž‡ƒ”Ž›— ŠŽ‡••Š›†”‘’Š‹Ž‹  –Šƒ–Š‡‘”‹‰‹ƒŽƤ„‡”•ǡ”‡‰ƒ”†Ž‡••‘ˆ™Š‡–Š‡”–Š‡Ƥ„‡”•Šƒ†„‡‡„Ž‡ƒ Š‡†‘”‘–ǤŠ‡ ‘–ƒ –ƒ‰Ž‡ ‘ˆ–Š‡‘”‹‰‹ƒŽ Š‡‹Ǧ–Š‡”‘‡ Šƒ‹ ƒŽ’—Ž’Ƥ„‡”™ƒ•— ŠŠ‹‰Š‡”–Šƒ–Šƒ–‘ˆ–Š‡‘”‹‰‹ƒŽ•‘ˆ–™‘‘† „Ž‡ƒ Š‡†”ƒˆ–’—Ž’Ƥ„‡”Ǥ —”–Š‡”‘”‡ǡ‹ ”‡ƒ•‡†—„‡”‘ˆ”‡ › Ž‹‰†‡ ”‡ƒ•‡†–Š‡ ‘–ƒ –ƒ‰Ž‡ ‘ˆ–Š‡ Š‡‹Ǧ–Š‡”‘‡ Šƒ‹ ƒŽ’—Ž’Ƥ„‡”ǤŠ‡ƒ‰‡‡“—ƒ–‹‘™ƒ•—•‡†–‘‡˜ƒŽ—ƒ–‡–Š‡•–”‡‰–Š ‘–”‹„—–‹‘•‘ˆ•‹‰Ž‡Ƥ„‡”ƒ†Ƥ„‡”ȂƤ„‡”„‘†‹‰–‘–‡•‹Ž‡•–”‡‰–Š‘ˆ’ƒ’‡”Ǥ•ƒ”‡•—Ž–ǡƒ ‹ ”‡ƒ•‡‹™‡ƒ‡••ˆƒ –‘”‘ˆƤ„‡”ȂƤ„‡”„‘†‹‰•–”‡‰–Š™ƒ•‘„–ƒ‹‡†ˆ‘”–Š‡”‡ › Ž‡†•‘ˆ–™‘‘† ”ƒˆ–’—Ž’Šƒ†•Š‡‡–Ǥ–Š‡‘–Š‡”Šƒ†ǡ–Š‡™‡ƒ‡••ˆƒ –‘”‘ˆ–Š‡‘”‹‰‹ƒŽ Š‡‹Ǧ–Š‡”‘‡ Šƒ‹ ƒŽ ’—Ž’Šƒ†•Š‡‡–†‡ ”‡ƒ•‡†™‹–Š”‡ › Ž‹‰Ǥ ƒ††‹–‹‘ǡ–Š‡™‡ƒ‡••ˆƒ –‘”‘ˆƤ„‡”ȂƤ„‡”„‘†‹‰ •–”‡‰–Šƒ†–Š‡ ‘–ƒ –ƒ‰Ž‡•‘ˆ–Š‡’”‘˜‹†‡†•‘ˆ–™‘‘†„Ž‡ƒ Š‡†”ƒˆ–’—Ž’Ƥ„‡”•„‘”‡ƒ ’”‘’‘”–‹‘ƒŽ”‡Žƒ–‹‘•Š‹’–‘‡ƒ Š‘–Š‡”Ǥ Paper is said to be environmentally friendly as a natural recycling material and a sustainable recycling resource. The paper recycling system has been constructed as an advanced field of recycling. In particular in Japan, recy- cling of used paper has been promoted from the viewpoint of effective use of resources and solution of waste problems. The wastepaper recovery rate began a rapid and long-term rise as recovery efforts in recent years. The recovery rate in Japan had reached 79.5% in 2019 1 . The wastepaper utilization rate at 64.3% within Japan was trailing by 15.2% compared with the recovery rate. However, the ratio of wastepaper to the raw material of paper and paperboard in Japan is one of the world’s leading. Although Japan’s waste paper recovery is at a fairly high level, there is a concern that the paper and paperboard recyclability will decline as the recovery rate rises. The utilization of recovered paper for high-grade paper such as printing and communication papers has been limited because using recovered paper tends to reduce the quality of these papers. Mckee 2 performed recycling of papermaking, drying, wetting and disintegration up to 6 times using soft- wood unbleached kraft pulp (SUKP). It was reported for the first time that physical properties of paper such as paper density, tensile strength, bursting strength, elongation, bending resistance and zero span tensile strength, decreased by recycle treatment but tearing strength and Taber stiffness increased when compared at the same freeness. Numerous studies have been conducted on the papermaking potential of recycled pulp fibers during the past decades 3–6 . The cell wall of wood pulp fiber can be distinguished into a primary wall (P layer) and a secondary wall (S layer), and the S layer is further divided into an outer layer (S1), a middle layer (S2), and an inner layer (S3). Among them, the S2 layer occupies approximately 70–80% of the cell wall thickness and is the main cell wall. In the case of chemical pulp, since lignin and the like are removed in the process of pulping, voids are formed in the cell wall portion and the pulp becomes porous 7 . When the chemical pulp is repeatedly defibrated in water, ͷ ‡›ƒ„‘”ƒ–‘”›‘ˆ‹‘Ǧ„ƒ•‡†ƒ–‡”‹ƒŽ ‹‡ ‡Ƭ‡ Š‘Ž‘‰›ȋ‘”–Š‡ƒ•– ‘”‡•–”›‹˜‡”•‹–›Ȍ‹‹•–”›‘ˆ †— ƒ–‹‘ǡ‘Ǥ͸ͼ ‡š‹‰‘ƒ†ǡ ƒ”„‹ͷͻͶͶͺͶǡŠ‹ƒǤ ͸ ‹˜‹•‹‘‘ˆƒ–—”ƒŽ‡•‘—” ‡•ƒ† ‘Ǧƒ–‡”‹ƒŽ•ǡ •–‹–—–‡ ‘ˆ‰”‹ —Ž–—”‡ǡ‘›‘‹˜‡”•‹–›‘ˆ‰”‹ —Ž–—”‡ƒ†‡ Š‘Ž‘‰›ǡ͹ǦͻǦ;ƒ‹™ƒ‹Ǧ Š‘ǡ — Š—ǡ‘›‘ͷ;͹Ǧ;ͻͶͿǡ ƒ’ƒǤ ͹ ƒ —Ž–›‘ˆ‰”‹ —Ž–—”‡ǡ‘›‘‹˜‡”•‹–›‘ˆ‰”‹ —Ž–—”‡ƒ†‡ Š‘Ž‘‰›ǡ͹ǦͻǦ;ƒ‹™ƒ‹Ǧ Š‘ǡ — Š—ǡ ‘›‘ͷ;͹Ǧ;ͻͶͿǡ ƒ’ƒǤ ͺ –ƒ–‡‡›ƒ„‘”ƒ–‘”›‘ˆ‹‘„ƒ•‡†ƒ–‡”‹ƒŽƒ† ”‡‡ƒ’‡”ƒ‹‰ǡ‹Ž—‹˜‡”•‹–›‘ˆ ‡ Š‘Ž‘‰›ǡŠƒ†‘‰ ƒ†‡›‘ˆ ‹‡ ‡•ǡ ‹ƒ͸ͻͶ͹ͻ͹ǡŠ‹ƒǤ * ‡ƒ‹Žǣ‡ˆ—Œ‹Šƒ‹Žƒ̻ ͷͼ͹Ǥ ‘Ǣ‘ƒ›ƒƒ̻ Ǥ–—ƒ–Ǥƒ ǤŒ’

 ‹‡–‹Ƥ ‡’‘”–• |

(2022) 12:1560

| Š––’•ǣȀȀ†‘‹Ǥ‘”‰ȀͷͶǤͷͶ͹;Ȁ•ͺͷͻͿ;ǦͶ͸͸ǦͶͻͻͷͺǦ͸

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