JP6573557B2 - Paper manufacturing method - Google Patents
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- JP6573557B2 JP6573557B2 JP2016010287A JP2016010287A JP6573557B2 JP 6573557 B2 JP6573557 B2 JP 6573557B2 JP 2016010287 A JP2016010287 A JP 2016010287A JP 2016010287 A JP2016010287 A JP 2016010287A JP 6573557 B2 JP6573557 B2 JP 6573557B2
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Description
本発明は紙の製造方法に関し、より詳しくは古紙を含む製紙原料の離解工程において特定量の硫酸カルシウムを添加することを含む、紙の製造方法に関する。 The present invention relates to a paper manufacturing method, and more particularly, to a paper manufacturing method including adding a specific amount of calcium sulfate in a disaggregation step of a papermaking raw material containing used paper.
近年の環境問題等を考慮して古紙の再利用が実施されている。例えば特許文献１には、廃石膏ボードから石膏残渣等を除去して古紙パルプを回収する方法が提案されている。 In consideration of environmental problems in recent years, waste paper has been reused. For example, Patent Document 1 proposes a method of recovering waste paper pulp by removing gypsum residues from waste gypsum board.
ところで紙の製造においては種々の薬品が使用されるので、各工程において薬品の反応等に起因して不溶性または難溶性の物質が生成して装置等に付着するという、いわゆるスケールがしばしば発生する。 By the way, since various chemicals are used in the manufacture of paper, a so-called scale is often generated in which an insoluble or hardly soluble substance is generated and adhered to an apparatus or the like due to a chemical reaction or the like in each process.
古紙原料を用いると硫酸カルシウムスケールの問題が特に顕著になる。これは添加される硫酸バンド由来の硫酸イオンと古紙原料に含まれる炭酸カルシウム由来のカルシウムイオンとの反応によって硫酸カルシウムが生成し、装置の壁等の表面で結晶化することが一因である。特に、硫酸カルシウムは強固で固いスケールを発生させるので除去が困難であり操業性を著しく低下させる。以上を鑑み、本発明は硫酸カルシウムスケールを低減した紙の製造方法を提供することを課題とする。 When waste paper raw materials are used, the problem of calcium sulfate scale becomes particularly noticeable. One reason for this is that calcium sulfate is generated by the reaction between the sulfate ion derived from the added sulfuric acid band and the calcium ion derived from calcium carbonate contained in the used paper raw material, and crystallizes on the surface of the wall of the apparatus. In particular, calcium sulfate generates a strong and hard scale, which makes it difficult to remove and significantly reduces operability. In view of the above, an object of the present invention is to provide a paper manufacturing method with reduced calcium sulfate scale.
発明者らは、離解工程において特定量の硫酸カルシウムを添加することで前記課題を解決できることを見出し、本発明を完成した。すなわち、前記課題は以下の本発明により解決される。
（１）古紙を含む製紙原料の固形分１００重量部に対し０．１〜２０重量部の硫酸カルシウムを添加し、前記原料を離解して紙料を得る工程、および前記紙料を抄紙する抄紙工程を含む、紙の製造方法。
（２）前記硫酸カルシウムがＣａＳＯ４・２Ｈ２ＯまたはＣａＳＯ４・０．５Ｈ２Ｏである、（１）に記載の製造方法。
（３）前記硫酸カルシウムを添加する工程が、石膏ボード由来の古紙原料であって硫酸カルシウムを含有する古紙原料を添加する工程である、（１）に記載の製造方法。
（４）前記抄紙工程において、ヘッドボックス内の前記紙料の硫酸カルシウムの２０℃における過飽和度が０．１〜２．０である、請求項１に記載の製造方法。
The inventors have found that the above problem can be solved by adding a specific amount of calcium sulfate in the disaggregation step, and have completed the present invention. That is, the said subject is solved by the following this invention.
(1) A step of adding 0.1 to 20 parts by weight of calcium sulfate to 100 parts by weight of a solid content of a papermaking raw material containing waste paper to obtain a stock by deaggregating the raw material, and papermaking for making the stock A method for producing paper, including a process.
(2) The production method according to (1), wherein the calcium sulfate is CaSO 4 · 2H 2 O or CaSO 4 · 0.5H 2 O.
(3) The manufacturing method according to (1), wherein the step of adding calcium sulfate is a step of adding a waste paper raw material derived from gypsum board and containing calcium sulfate.
(4) The manufacturing method according to claim 1, wherein in the paper making step, the supersaturation degree at 20 ° C of calcium sulfate of the stock in the head box is 0.1 to 2.0.
本発明により硫酸カルシウムスケールを低減した紙の製造方法が提供できる。 According to the present invention, a paper manufacturing method with reduced calcium sulfate scale can be provided.
以下、本発明を詳細に説明する。本発明において「〜」はその両端の値を含む。すなわち「Ｘ〜Ｙ」との範囲は両端の値ＸおよびＹを含む。 Hereinafter, the present invention will be described in detail. In the present invention, “to” includes values at both ends thereof. That is, the range of “X to Y” includes the values X and Y at both ends.
１．紙の製造方法
古紙を含む製紙原料の固形分１００重量部に対し０．１〜２０重量部の硫酸カルシウムを添加し、前記原料を離解して紙料を得る工程、および前記紙料を抄紙する抄紙工程を含む。
1. A method for producing paper A step of adding 0.1 to 20 parts by weight of calcium sulfate to 100 parts by weight of a solid content of a papermaking raw material including waste paper, obtaining a stock by deaggregating the raw material, and papermaking the stock Includes paper making process.
（１）古紙を含む製紙原料
古紙を含む製紙原料とは、一度製造された紙から回収した古紙を含む製紙用の原料である。したがって当該原料から得られる紙料は、パルプ繊維以外に填料や塗工層由来の顔料等を含む。本発明においては、例えば、印刷用紙、板紙等の通常の紙由来の古紙を含む製紙原料を使用できる。以下、本発明で用いる古紙を含む製紙原料を「原料Ａ」ともいう。後述するとおり、本発明は原料Ａに硫酸カルシウムを添加するために、原料Ａに石膏ボード由来の古紙を添加する態様を含む。石膏ボード由来の古紙は通常、原料の全固形分中１０〜５０重量％程度の石膏（硫酸カルシウム）を含む。よって、本発明で使用する原料Ａは硫酸カルシウムを含まないか、前記濃度未満の硫酸カルシウムを含むことが好ましい。
(1) Papermaking raw material containing used paper The papermaking raw material containing used paper is a raw material for papermaking containing used paper collected from paper once produced. Therefore, the paper stock obtained from the raw material contains fillers and pigments derived from the coating layer in addition to pulp fibers. In the present invention, for example, a papermaking raw material containing used paper derived from normal paper such as printing paper and paperboard can be used. Hereinafter, the papermaking raw material containing waste paper used in the present invention is also referred to as “raw material A”. As will be described later, the present invention includes a mode in which waste paper derived from gypsum board is added to the raw material A in order to add calcium sulfate to the raw material A. Waste paper derived from gypsum board usually contains about 10 to 50% by weight of gypsum (calcium sulfate) in the total solid content of the raw material. Therefore, it is preferable that the raw material A used in the present invention does not contain calcium sulfate or contains calcium sulfate of less than the above concentration.
（２）硫酸カルシウム
本工程では前記原料（原料Ａ）に硫酸カルシウムを添加する。硫酸カルシウムとはカルシウムの硫酸塩であり、無水物（ＣａＳＯ２）、０．５水和物（ＣａＳＯ４・０．５Ｈ２Ｏ）、および２水和物（ＣａＳＯ４・２Ｈ２Ｏ）が存在する。本発明においては入手が容易であることから、２水和物または０．５水和物が好ましく、２水和物がより好ましい。粒状の硫酸カルシウムを添加することが好ましい。
(2) Calcium sulfate In this step, calcium sulfate is added to the raw material (raw material A). Calcium sulfate is a sulfate of calcium, and there are anhydrous (CaSO 2 ), 0.5 hydrate (CaSO 4 · 0.5H 2 O), and dihydrate (CaSO 4 · 2H 2 O). To do. In the present invention, since it is easily available, dihydrate or 0.5 hydrate is preferable, and dihydrate is more preferable. It is preferable to add granular calcium sulfate.
硫酸カルシウムを添加することでスケールが回避できるメカニズムは後述するが、硫酸カルシウムの添加量が少なすぎるとこの効果が十分でなく、多すぎると製品に含まれる硫酸カルシウムの含有量が増加し、製品強度の低下を引き起こす恐れがある。よって、硫酸カルシウムの添加量は原料の固形分の合計１００重量部に対して０．１〜２０重量部であり、好ましくは０．３〜１５重量部である。原料の固形分とは、原料Ａに含まれるすべての固形成分であり、パルプ、填料、および顔料等である。 The mechanism by which the scale can be avoided by adding calcium sulfate will be described later, but if the amount of calcium sulfate added is too small, this effect will not be sufficient, and if it is too much, the content of calcium sulfate contained in the product will increase. May cause a decrease in strength. Therefore, the addition amount of calcium sulfate is 0.1 to 20 parts by weight, preferably 0.3 to 15 parts by weight, based on 100 parts by weight of the total solid content of the raw material. The solid content of the raw material is all solid components contained in the raw material A and includes pulp, fillers, pigments and the like.
硫酸カルシウムの添加は、石膏ボード由来の古紙原料であって硫酸カルシウムを含有する古紙原料を添加することによって行ってもよい。石膏ボード由来の古紙原料であって硫酸カルシウムを含有する古紙原料とは、廃石膏ボードから得られる材料であり、石膏（硫酸カルシウム）の他にパルプ繊維等を含んでいてもよい。当該古紙原料（以下「原料Ｂ」ともいう）の配合割合は、前記硫酸カルシウムの濃度を達成できるように適宜調整されるが、１００重量部の原料Ａに対して、５０重量部未満であることが好ましく、４０重量部以下であることがより好ましく、３０重量部以下であることがさらに好ましい。原料Ｂの前記添加量が多いと抄紙した際の紙の灰分が高くなり、強度の低下などを引き起こす恐れがあるので好ましくない。したがって、原料Ｂと、これとは別の硫酸カルシウムを併用して、前記濃度を達成してもよい。 The addition of calcium sulfate may be performed by adding a waste paper raw material derived from gypsum board and containing calcium sulfate. The waste paper raw material derived from gypsum board and containing calcium sulfate is a material obtained from waste gypsum board, and may contain pulp fibers in addition to gypsum (calcium sulfate). The mixing ratio of the waste paper raw material (hereinafter also referred to as “raw material B”) is appropriately adjusted so as to achieve the calcium sulfate concentration, but is less than 50 parts by weight with respect to 100 parts by weight of raw material A. Is preferably 40 parts by weight or less, and more preferably 30 parts by weight or less. When the amount of the raw material B added is large, the ash content of the paper at the time of paper making increases, which may cause a decrease in strength and the like. Therefore, the said density | concentration may be achieved using raw material B and calcium sulfate different from this together.
（３）パルプの離解
本工程では、硫酸カルシウムが添加された原料Ａを離解する。離解はパルパー等の当該分野で通常使用される装置を用いて実施できる。離解条件等も当該分野で公知のとおりとしてよい。当該工程で得られる紙料中の硫酸カルシウム濃度は紙料中０．１〜２０重量％であることが好ましい。
(3) Disaggregation of pulp In this step, the raw material A to which calcium sulfate has been added is disaggregated. The disaggregation can be carried out using a device usually used in the field such as a pulper. The disaggregation conditions and the like may be as known in the art. The calcium sulfate concentration in the stock obtained in this step is preferably 0.1 to 20% by weight in the stock.
（４）パルプ処理、調成
上記離解後、異物を除去するために、当該分野で公知のクリーナーや丸穴スクリーン、スリットスクリーンなどの装置を用いて離解されたパルプを処理することができる。必要に応じて洗浄や濃縮処理を行ってもよい。ただしこれらの処理は必ずしも石膏分の除去を目的とはしない。また、必要に応じて歩留剤、紙力増強剤、凝集剤など、当該分野で公知の薬品を添加してもよい。
(4) Pulp treatment, preparation After the above-mentioned disaggregation, the disaggregated pulp can be treated using a device known in the art such as a cleaner, a round hole screen, and a slit screen in order to remove foreign matters. You may perform washing | cleaning and a concentration process as needed. However, these treatments are not necessarily aimed at removing gypsum. Moreover, you may add chemical | medical agents well-known in the said field, such as a retention agent, a paper strength enhancer, and a flocculant as needed.
（５）抄紙
本工程においては、前記（１）〜（４）の工程を含む方法で製造した紙料を抄紙する。抄紙工程は当該分野で公知の装置および条件を適用して実施してよい。例えば、抄紙機としては、長網型湿式抄紙機、ツインワイヤー抄紙機、ヤンキー抄紙機、円網抄紙機、円網短網コンビネーション抄紙機が挙げられる。
(5) Papermaking In this step, the paper stock manufactured by the method including the steps (1) to (4) is made. The paper making process may be performed by applying apparatuses and conditions known in the art. For example, examples of the paper machine include a long net type wet paper machine, a twin wire paper machine, a Yankee paper machine, a circular net paper machine, and a short net combination machine.
２．メカニズム等
本発明によって硫酸カルシウムのスケールが低減できるメカニズムは限定されないが、添加した硫酸カルシウムが種晶のような機能を発現することによると考えられる。すなわち、添加した硫酸カルシウム表面に、紙料中や白水中（以下まとめて「系中」ともいう）に存在する硫酸イオンおよびカルシウムイオンが硫酸カルシウムを生成しながら析出する。つまり系中に存在する当該イオンを添加した硫酸カルシウムがトラップするので、装置の壁等へのスケールが妨げられると考えられる。
2. Mechanism, etc. The mechanism by which the scale of calcium sulfate can be reduced according to the present invention is not limited, but it is considered that the added calcium sulfate expresses a function like a seed crystal. That is, sulfate ions and calcium ions present in the stock and white water (hereinafter collectively referred to as “in the system”) precipitate on the added calcium sulfate surface while producing calcium sulfate. That is, it is considered that the calcium sulfate to which the ions existing in the system are added is trapped, so that the scale to the wall of the apparatus is hindered.
一方、添加した硫酸カルシウムが存在しないと、系中では硫酸イオンおよびカルシウムイオンの濃度が高くなって過飽和の状態となり、装置の壁等に核となる箇所があればそこを起点にスケールが発生する。したがって、系中の硫酸カルシウムの過飽和度により、製造工程におけるスケールの発生しやすさをモニターすることができる。過飽和度は２０℃において具体的に（硫酸イオン濃度）×（カルシウムイオン濃度）／（硫酸カルシウムの飽和濃度）として求めることができる。本発明においては紙料中の過飽和度が０．１〜２．０であることが好ましく、０．１〜１．９であることがより好ましく、０．１〜１．８であることがさらに好ましく０．１〜１．３であることが特に好ましい。また、硫酸や硫酸バンドなどの薬品を試料に添加することで過飽和度を調整することができる。本発明においてはヘッドボックス中の紙料の過飽和度が前記範囲にあることが好ましい。ヘッドボックスとは紙料を貯留し、抄紙網に紙料を供給するための装置である。 On the other hand, if the added calcium sulfate does not exist, the concentration of sulfate ion and calcium ion in the system becomes high and becomes supersaturated, and if there is a core part on the wall of the device, scale will start from there . Therefore, it is possible to monitor the ease of scale generation in the production process based on the degree of supersaturation of calcium sulfate in the system. The degree of supersaturation can be specifically obtained at 20 ° C. as (sulfate ion concentration) × (calcium ion concentration) / (saturation concentration of calcium sulfate). In the present invention, the degree of supersaturation in the paper stock is preferably 0.1 to 2.0, more preferably 0.1 to 1.9, and further preferably 0.1 to 1.8. It is particularly preferably 0.1 to 1.3. Further, the degree of supersaturation can be adjusted by adding chemicals such as sulfuric acid and sulfuric acid band to the sample. In the present invention, it is preferable that the supersaturation degree of the stock in the head box is in the above range. A head box is an apparatus for storing paper stock and supplying the stock to a papermaking net.
３．本発明で得られる紙
添加した硫酸カルシウムおよび系中の前記イオンをトラップした硫酸カルシウムは最終的に製造される紙の中に取り込まれ、取り込まれない分は製造工程中を循環する。このため、本発明によって製造された紙中の硫酸カルシウム濃度は比較的高い。硫酸カルシウムは、紙の全固形成分１００重量部中、０．１〜２０重量部含まれることが好ましい。
3. Paper obtained in the present invention The added calcium sulfate and calcium sulfate trapped by the ions in the system are taken into the paper finally produced, and the portion not taken in is circulated in the production process. For this reason, the calcium sulfate concentration in the paper produced according to the present invention is relatively high. It is preferable that 0.1-20 weight part of calcium sulfate is contained in 100 weight part of the total solid component of paper.
以下、実施例を挙げて本発明を詳細に説明する。
古紙を含む製紙原料として、段ボール古紙および雑誌古紙を５０／５０（重量比）で混合したものを用い、長網抄紙機を用いて紙を製造した。
Hereinafter, the present invention will be described in detail with reference to examples.
As a papermaking raw material containing used paper, a cardboard used paper and magazine used paper mixed at 50/50 (weight ratio) were used, and paper was manufactured using a long net paper machine.
［実施例１］
古紙を含む製原料の固形成分１００重量部に対し０．５重量部の硫酸カルシウムを添加し、パルパーを用いてパルプを離解した。その後、クリーナーを用いて重量異物を除去した後、スリットスクリーン（０．２５ｍｍ巾）を用いて異物を除去した。このようにして得た紙料をヘッドボックスから長網抄紙機に吐出して抄紙速度３００ｍ／分で抄紙して、坪量が１２０ｇ／ｍ２の紙を製造した。製造開始時点でヘッドボックス内の紙料を採取して、２０℃の雰囲気下に静置した。次いで紙料中の硫酸イオン濃度およびカルシウムイオン濃度を測定した。前述の式に基づいて硫酸カルシウム過飽和度を算出したところ、１．３であった。本例ではいずれの工程においてもスケールは発生しなかった。
[Example 1]
0.5 parts by weight of calcium sulfate was added to 100 parts by weight of the solid component of the raw material including waste paper, and the pulp was disaggregated using a pulper. Then, after removing heavy foreign substances using a cleaner, foreign substances were removed using a slit screen (0.25 mm width). The paper stock thus obtained was discharged from the head box to a long paper machine and paper was made at a paper making speed of 300 m / min to produce a paper having a basis weight of 120 g / m 2 . The paper stock in the head box was sampled at the start of production and allowed to stand in an atmosphere at 20 ° C. Next, the sulfate ion concentration and calcium ion concentration in the paper stock were measured. The calcium sulfate supersaturation calculated based on the above formula was 1.3. In this example, scale did not occur in any step.
［比較例１］
硫酸カルシウムを添加しなかった以外は実施例１と同様にして紙を製造した。製造開始時の硫酸カルシウム過飽和度は２．５であった。本例で、このまま製造を継続するとスケールが発生した。
[Comparative Example 1]
A paper was produced in the same manner as in Example 1 except that calcium sulfate was not added. The calcium sulfate supersaturation at the start of production was 2.5. In this example, when production was continued as it was, scale was generated.
［実施例２］
古紙を含む製紙原料の固形成分１００重量部に対し３．２重量部の硫酸カルシウムを添加した以外は、実施例１と同様にして紙を製造した。製造開始時点における紙料中の硫酸カルシウム過飽和度は２．０であった。本例ではいずれの工程においてもスケールは発生しなかった。
[Example 2]
A paper was produced in the same manner as in Example 1 except that 3.2 parts by weight of calcium sulfate was added to 100 parts by weight of the solid component of the papermaking raw material including waste paper. The supersaturation degree of calcium sulfate in the paper stock at the start of production was 2.0. In this example, scale did not occur in any step.
［比較例２］
硫酸カルシウムを添加しなかった以外は実施例１と同様にして紙を製造した。製造開始時の硫酸カルシウム過飽和度は２．１であった。本例で製造を継続するとスケールが発生した。
[Comparative Example 2]
A paper was produced in the same manner as in Example 1 except that calcium sulfate was not added. The calcium sulfate supersaturation at the start of production was 2.1. When production was continued in this example, scale was generated.
本発明により、スケールを発生させることなく紙を製造することが可能となる。 According to the present invention, paper can be manufactured without generating scale.
Claims (3)
前記紙料を抄紙する抄紙工程を含む、
紙の製造方法。 Adding 0.1 to 20 parts by weight of calcium sulfate not derived from used paper raw material to 100 parts by weight of the solid content of the papermaking raw material including used paper, and separating the raw material to obtain a paper material, and papermaking the paper material Including paper making process,
Paper manufacturing method.
過飽和度＝（硫酸イオン濃度）×（カルシウムイオン濃度）／（硫酸カルシウムの飽和濃度）
請求項１に記載の製造方法。 The supersaturation degree defined below at 20 ° C. of calcium sulfate of the stock in the head box in the paper making process is 0.1 to 2.0.
Supersaturation = (sulfate ion concentration) × (calcium ion concentration) / (saturation concentration of calcium sulfate)
The manufacturing method according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016010287A JP6573557B2 (en) | 2016-01-22 | 2016-01-22 | Paper manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016010287A JP6573557B2 (en) | 2016-01-22 | 2016-01-22 | Paper manufacturing method |
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