JP2002173884A - Recording paper and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain recording paper including deinked pulp generated from waste paper such as newspaper, magazines and the likes, generating no feathering even when recorded by ink jet printer, excellent in strengths and capable of being used as shared copy paper and provide a method for producing the same. SOLUTION: In a method for producing recording paper by using deinked pulp produced through plural processes having at least a digesting process of waste plural processes having at process, the recording paper is produced by adding minutely fibrillated cellulose to raw material pulp blended with deinked pulp obtained by treating the pulp by adding a cationic polymer in either one or more of a plurality of the processes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording paper manufactured from deinked pulp made from used paper such as newspapers and magazines and a method for manufacturing the same. The present invention also relates to a recording sheet and a method for manufacturing the recording sheet which can also be used.

[0002]

2. Description of the Related Art Deinked pulp is used as a raw material for papermaking together with wood pulp from the viewpoint of resource saving and measures against municipal waste treatment, and is widely used in the fields of newspapers and magazines. In general, the method for producing deinked pulp is to separate the ink and the pulp by washing or flotation, etc., after the waste paper disintegration process, the deinking process such as kneading in the presence of a deinking agent and alkali, etc. ), Followed by washing and bleaching as necessary. For example, waste paper on which newspapers or magazines are printed is disintegrated with an alkaline chemical or the like using a disintegrator such as a pulper, and alkali soaking (alkali immersion) is further performed by adding an alkaline chemical, hydrogen peroxide or a surfactant.
At the same time, the pulp fibers are swollen by using mechanical stirring force, the ink and the pulp are separated, and then the ink is separated from the pulp by washing or flotation to produce deinked pulp. In Japan, the recovery rate of used paper as a raw material for paper is about 50%, but with the aim of using more recycled paper,
The use of waste paper pulp is increasing in general paper as well as in recording paper such as copy paper. In recent years, personal computers have spread not only in offices but also in homes, and accordingly, the spread of inkjet printers has been remarkable. As the output paper of the inkjet printer, there is a special coated paper, but a copy paper is also used. However, when ink jet recording is performed on copy paper containing deinked pulp, characters become difficult to read due to feathering (whisker-like bleeding of ink),
When variable data such as a barcode is recorded, there is a problem that it is difficult to read the barcode or the like. In order to solve this, when making paper using pulp slurry containing pulp containing deinked pulp, add a large amount of internal sizing agent, or use a size press device or the like on the surface of the paper made. For example, a surface sizing agent is applied, but a satisfactory product has not been obtained. In addition, deinked pulp deteriorates due to deterioration due to repeated wetting and drying, and aging due to the effects of humidity, temperature, atmospheric oxygen and ultraviolet rays. In addition, various troubles occur because the strength of the pulp is inferior to that of the pulp made of only virgin. For example, when used in a laser beam printer or a copier, which is widely used as an output of a personal computer, paper powder is generated due to low surface strength, which adversely affects the printer. As a method for improving the surface strength, a surface treatment agent such as starch or polyvinyl alcohol may be applied to the surface, but these methods have a limitation in improving the surface strength, and the coating components However, such problems as sticking to the drum may not be sufficient measures.

[0003]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a newspaper / magazine which does not cause feathering when recorded by an ink jet printer and has excellent strength and can be used as a co-paper for copying. It is an object of the present invention to provide a recording paper containing deinked pulp recycled from waste paper such as paper, and a method for producing the same.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found the following method. That is, in a method for producing a deinked pulp comprising a plurality of steps including at least a disintegration step of waste paper and a deinking step using a surfactant-based deinking agent, the method includes any one or more of the plurality of steps. The present invention is achieved by adding a cationic polymer, and adding fine fibrillated cellulose to the raw pulp containing the deinked pulp produced by the method of deinking in the presence of the cationic polymer to form a paper. Reached. The paper containing the deinked pulp obtained by this method has no or significantly improved feathering when recorded using an ink jet method, especially an aqueous ink, and has excellent surface strength and other laser beam printers. And a paper that could be used with a copier.

The reason why the above-mentioned object is achieved by the present invention is not necessarily clear, but is considered as follows.
The production of deinked pulp includes the steps of defibration, deinking, washing, and bleaching, and is performed by combining these steps according to the type of waste paper and the purpose of use of the deinked pulp. When disintegrating waste paper with a pulper, an alkaline chemical is added to increase the water absorption of the waste paper, and the fibers are rubbed by mechanical agitation to separate the waste paper into individual fibers and the ink is separated from the fibers. -Peel off. Further, a surfactant-based deinking agent is added together with an alkaline chemical to promote separation and peeling of the ink from the fiber, and subsequently, the ink separated from the fiber by a washing method or a flotation method is discharged out of the system. In the deinked pulp manufactured by this method, a deinking agent mainly composed of a surfactant is firmly bonded to the fiber surface or penetrates into the fiber. Since the surfactant cannot be completely washed away with the washing degree of, such deinked pulp is blended with virgin pulp, and when recording is performed on an ink-jet recording system using a water-based ink on a recording paper, the ink is partially removed. It is considered that feathering occurs due to extremely large bleeding.

In the present invention, when producing deinked pulp,
By treating the pulp with a cationic polymer, it was possible to obtain a recording paper free of this feathering.
We do not know exactly how this works, but we believe it is for the following reasons. The ink dye used in the ink jet system has an anionic group such as a sulfonic acid group and a carboxyl group. By treating waste paper pulp with a cationic polymer, a cationic group is present on the surface or inside of the pulp fiber. For this reason, it is considered that an ionic bond and a coordination bond occur between the cationic polymer and the dye in the ink to form a complex or a complex salt, and the dye becomes water-insoluble, and the dye is instantaneously separated and fixed from the ink solution layer. Can be

[0007] The fine fibrillated cellulose added to the raw pulp is mechanically, physically and mechanically added to the cellulose fiber.
It is made fine by chemical treatment. For example, when the pulp slurry is refined and observed with an optical microscope, when the water retention value is 210 to 250%, the fiber width is 20 to 30 μm.
m of pulp fiber is partially destroyed, and fibrils with a fiber width of 3 to 5 μm increase, and these fibers are in a shape in which several to several tens of fibers are partially bound or entangled. When the fibers are observed with a scanning microscope, fine fibers having a fiber width of 0.5 μm or less are also observed. It is presumed that such a fine fiber width of the fine fibrillated cellulose contributes to an increase in the fiber surface area and an increase in the number of networks between fibers, and serves to strengthen the inter-fiber bonds of the pulp, thereby improving the strength.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the treatment with a cationic polymer is preferably carried out before adding a surfactant-based deinking agent, and more preferably after adding an alkaline chemical. Good before adding black ink. Further, it can be added to a plurality of steps of the deinking pulp manufacturing process. It is preferable that the amount of the alkaline chemical added is as small as possible.

The cationic polymer used in the present invention is not particularly limited. For example, dicyandiamide / alkylamine polymer, dicyandiamide / formalin polymer, polyethyleneimine derivative, alkylamine / epichlorohydrin polymer, Commercially available chemicals such as ammonia / epichlorohydrin-based polymer compounds, polymethacrylic acid-based quaternary ammonium salt derivatives, and dimethyldiallylammonium chloride-based polymer can be mentioned, and among them, alkylamine / epichlorohydrin-based polymer compounds and dimethyl The use of a diallylammonium chloride-based polymer is preferable because the effect is obtained even in a smaller amount than other cationic polymers.

In the present invention, the amount of the cationic polymer to be added is preferably in the range of 0.2 to 5.0% by weight, more preferably in the range of 1.0 to 2.5% by weight, based on the absolute dry weight of the deinked pulp. Is preferred. When the amount of the cationic polymer is less than 0.2% by weight based on the absolute dry weight of the deinked pulp,
When recording is performed by an ink jet printer using an aqueous ink on recording paper made by mixing the pulp and virgin chemical pulp, feathering tends to increase and the recording quality tends to be inferior. On the other hand, when the amount of the cationic polymer added is more than 5.0% by weight based on the absolute dry weight of the deinked pulp and treated, the cation concentration may be too high to cause flocking of the pulp fiber. In addition, the effect on feathering does not change significantly, which is not preferable from the viewpoint of cost.

The surfactant-based deinking agents of the present invention include:
Anionic surfactants such as carboxylic acid type, sulfate ester type, sulfonic acid type and phosphate ester type, nonionic surfactants such as ether type, ester type and fatty acid alkylol amide type, amphoteric type such as amino acid type and betaine type Surfactants can be used. These can be used alone or in combination.

As the alkaline chemical of the present invention, known chemicals such as caustic soda, soda ash, sodium bicarbonate, and sodium silicate are used, but caustic soda is preferably used in consideration of handling and cost. In addition, when an alkaline chemical is used in the defibration step, the addition amount is preferably as small as possible because the effect of the cationic polymer used may be reduced in some cases, and is preferably 1.0% by weight or less based on waste paper pulp. .

In the present invention, the addition of the fine fibrillated cellulose is preferably added to the deinked pulp before mixing the deinked pulp with the virgin pulp. The fine fibrillated cellulose used in the present invention has an average fiber length of 0.0
Those having a thickness of 1 to 0.4 mm are preferred. If it is less than 0.01 mm, the fine fibrillated cellulose is too small, and the ratio of the fine fibrillated cellulose flowing out of the papermaking net at the time of papermaking becomes large, and the effect is reduced. If the length is longer than 0.4 mm, the specific surface area is reduced, and the effect is also reduced.

Various methods have been known as methods for producing microfibrillated cellulose in the present invention, and any method may have an average fiber length of 0.01 to 0.01.
If it becomes 0.4 mm, it can be used.
For example, a method using various beaters such as beaters, refiners, etc.
A method in which a small-diameter orifice is passed at a high speed with a pressure difference of 0 psi and then collides and rapidly decelerates to perform a cutting action. The impeller is rotated by a drive shaft with a bell to impact the fiber material. Applying mechanical shearing force to cellulose fiber, such as a method of applying, a method of performing fine pulverization by a dry method using a rotor and a hammer disposed in a housing, a method using a medium stirring wet pulverizer, a method using a pulverizer such as a vibration mill, a sand mill, and the like Thus, a method of producing fine fibrillated cellulose can be mentioned. Further, not only a mechanical treatment but also a method using a combination of a chemical treatment such as an acid hydrolysis treatment, an alkali treatment, a liquid ammonia treatment, an enzyme treatment, and a steam treatment and a mechanical treatment has been proposed.

As a raw material of the fine fibrillated cellulose in the present invention, hardwood bleached kraft pulp (LBK)
P), softwood bleached kraft pulp (NBKP), hardwood bleached sulphite pulp (LBSP), softwood bleached sulphite pulp (NBSP) and other chemical pulp, groundwood pulp (GP) and thermomechanical pulp (TMP) etc. And non-wood pulp such as cotton pulp, hemp, bagasse, kenaf, esparto, kozo, mitsumata, and goose.

In the present invention, the added amount of the fine fibrillated cellulose is 0.5 to 0.5% based on the absolute dry weight of the whole pulp.
A range of 15% by weight is preferred. When the addition amount of the fine fibrillated cellulose is less than 0.5% by weight based on the absolute dry weight of the whole pulp, the effect of the addition is hardly seen. On the other hand, when the added amount of the fine fibrillated cellulose is more than 15% by weight, the drainage becomes poor at the time of paper making using this raw material, dehydration from the wire is difficult, and paper breakage is likely to occur.

As the raw material pulp of the recording paper in the present invention, a conventionally used pulp can be used in addition to the deinked pulp. For example, LBKP, NBKP, LB
Wood pulp such as chemical pulp such as SP and NBSP and mechanical pulp such as GP and TMP can be used. Furthermore, cotton pulp, hemp, bagasse, kenaf, esparto, mulberry,
Non-wood pulp such as mitsumata and goosepicks can also be used.

Further, a filler and other chemicals such as a sizing agent can be internally added to the recording paper as required. The filler internally added to the recording paper of the present invention is not particularly limited, and can be appropriately selected from known fillers and used. Examples of such a filler include talc, kaolin, illite, clay, calcium carbonate, titanium dioxide and the like. The filler is usually used in an amount of 3 to 20% by weight as a filler in paper. The internal sizing agent used for recording paper in the present invention is not particularly limited, and can be appropriately selected from known internal sizing agents used for printing paper and ink jet recording paper. Preferred internal sizing agents include, for example, hydrophobic modified rosin emulsion sizing agents. Usually, the amount of the internal sizing agent used is adjusted in the range of 0.1 to 0.7% based on the absolute dry weight of the pulp, but is not particularly limited. Further, in addition to the above, if necessary, an antifoaming agent, a pH adjuster, a dye or a color pigment for adjusting the hue, and a fluorescent dye for improving the visual whiteness are further added to the recording paper. You can also.

The recording paper of the present invention can be coated with a sizing liquid containing a known sizing agent, binder and the like, if necessary. As means for coating, known coating devices such as various blade coaters, roll coaters, air knife coaters, bar coaters, curtain coaters, gravure coaters, gate roll coaters and the like can be used, and can be provided on one or both surfaces. Although it is possible, from the viewpoint of operability and cost, it is preferable to use a size press coating method capable of coating both surfaces simultaneously on-machine. Further, as the surface finish, various calenders such as a machine calender, a soft calender, and a super calender can be used alone or in combination.

[0020]

EXAMPLES The specific structure of the recording sheet of the present invention will be described below with reference to examples, and the characteristics of the recording sheet will be described in comparison with comparative examples. However, the present invention is not limited to this example. is not. In the examples, “%” indicates “% by weight”, and “parts” indicates “parts by weight”. Example 1 Waste newspaper was put into a test pulper with water so as to have a pulp concentration of 5%.
After adding 0% and disintegrating for 5 minutes, an alkylamine / ammonia / epichlorohydrin polycondensate (PF-700, manufactured by Showa Polymer Co., Ltd.) as a cationic polymer was added in an amount of 2.0% based on the absolute dry weight of the pulp. Stirring for 18 minutes, concentration 18
%. Water was added to the mixture to dilute it to 2%, and a surfactant-based deinking agent (DI-767, manufactured by Kao Corporation) was added to the pulp at 1.0%. The mixture was subjected to a flotation treatment for minutes, and dehydrated to a concentration of 18%. Add more water and 2
%, NaOH 2.0%, NaSiO ₃ 4.0%,
After adding 3.0% of H ₂ O _{2, the} mixture was mixed with a steam mixer and bleached at a temperature of 70 ° C. for 3 hours. Then wash and dehydrate 1
8% of deinked pulp was obtained.

70 parts of deinked pulp obtained by the above manufacturing method,
Hardwood bleached kraft pulp with a beating degree of 400 ml (L-BK
P) 5 parts of fine fibrillated cellulose having a number average fiber length of 0.15 mm, 7 parts of talc, 1.5 parts of sulfuric acid band, 0.4 part of sizing agent, 0.02 part of retention aid in 30 parts of pulp slurry A part was added and hand-sheeted. After drying, using a two-roll size press, the coating liquid 1 was applied on both sides so that the coating amount was 4 g / m ^{2 as a} solid content, and a recording paper having a basis weight of 74 g / m ² was obtained. (Coating liquid 1) Water-soluble polymer: oxidized starch MS # 3600 (manufactured by Nippon Shokuhin Kako Co., Ltd.) 100 parts Surface sizing agent: Polymalon 360 (manufactured by Arakawa Chemical) 2 parts Antifoaming agent: Nopco 8034L (manufactured by San Nopco) 0 is the amount of .1 parts example 2 microfibrillated cellulose except that the 0.5 parts to obtain a recording paper having a basis weight of 74 g / m ² in the same manner as in example 1. Example 3 Recording paper having a basis weight of 74 g / m ² was obtained in the same manner as in Example 1 except that the amount of the fine fibrillated cellulose was changed to 15 parts. Example 4 Recording paper having a basis weight of 74 g / m ² was obtained in the same manner as in Example 1 except that the amount of the cationic polymer added was 0.2%. Example 5 Recording paper having a basis weight of 74 g / m ² was obtained in the same manner as in Example 1 except that the amount of the cationic polymer added was 5.0%. Example 6 The cationic polymer was a dimethyldiallylammonium chloride polymer (PAS-H-10L, Nitto Boseki Co., Ltd.)
And a recording paper having a basis weight of 74 g / m ² was obtained in the same manner as in Example 1 except that 2.0% was added. Example 7 The cationic polymer was polyethyleneimine (Epomin P
P-061, manufactured by Nippon Shokubai Co., Ltd.), and a recording paper having a basis weight of 74 g / m ² was obtained in the same manner as in Example 1 except that 2.0% was added. Example 8 Changing the cationic polymer to polyethylene imine
A basis weight of 74 was obtained in the same manner as in Example 1 except that 0% was added.
g / m ² of recording paper was obtained. Example 9 Recording paper having a basis weight of 74 g / m ² was obtained in the same manner as in Example 1 except that the amount of the cationic polymer added was 10.0%. Example 10 Water was added to a test pulper with used newspaper paper so as to have a pulp concentration of 5%.
After adding 0% and disintegrating for 5 minutes, the mixture was dehydrated to a concentration of 18%. Water was added to the mixture to dilute it to 2%, and a surfactant-based deinking agent (DI-767, manufactured by Kao Corporation) was added to the pulp at 1.0%, and a test floatator was used for 6 minutes. , A flotation treatment, and adding 2.0% of an alkylamine / ammonia / epichlorohydrin polycondensate as a cationic polymer to the pulp absolute dry weight,
The mixture was stirred for 30 minutes and dehydrated to a concentration of 18%. Further dilute to 2% by adding water, 2.0% NaOH, NaSiO
₃ 4.0%, was mixed with H ₂ O ₂ 3.0% after addition steam mixer, bleached 3 hours at a temperature 70 ° C.. Thereafter, washing and dewatering were performed to obtain an 18% deinked pulp.

A recording paper having a basis weight of 74 g / m ² was obtained in the same manner as in Example 1 except that deinked pulp was obtained by the above manufacturing method. Comparative Example 1 A basis weight of 7 was obtained in the same manner as in Example 1 except that microfibrillated cellulose was not added (the amount added was 0%).
4 g / m ² of recording paper was obtained. Comparative Example 2 No cationic polymer was added (addition amount: 0%)
Recording paper having a basis weight of 74 g / m ² was obtained in the same manner as in Example 1 except that Comparative Example 3 In the same manner as in Example 1 except that the cationic polymer was not added when producing the deinked pulp, and 40 parts of an alkylamine / ammonia / epichlorohydrin polycondensate was added to the coating liquid 1 as the cationic polymer. Recording paper having a basis weight of 74 g / m ² was obtained. Comparative Example 4 To pulp slurry consisting of 100 parts of L-BKP having a beating degree of 400 ml, 7 parts of talc, 1.5 parts of sulfuric acid band, 0.4 parts of sizing agent and 0.02 parts of retention aid were added and hand-made. Was. After drying, using a two-roll size press, the coating liquid 1 was applied on both sides so that the coating amount was 4 g / m ^{2 as a} solid content, and a recording paper having a basis weight of 74 g / m ² was obtained. An ink jet recording test and a strength test of the recording papers obtained in Examples 1 to 5 were performed by the following methods. The results are as summarized in Tables 1 and 2.

[0023]

[Table 1]

[0024]

[Table 2]

(1) Inkjet recording test The recording test was performed using an inkjet printer (BJC-420).
J: trade name, manufactured by Canon Inc.), and a predetermined pattern was recorded, and evaluated according to the following criteria. a, Ink-like bleeding of ink (feathering) Bleeding of whisker-like ink was visually evaluated.

○ No whisker-like bleeding, △ Slight whisker-like bleeding, × Many whisker-like bleeding, b, ink dryness Immediately after recording, the image area was rubbed with a finger, and the degree of dirt was visually evaluated. .

○ No dirt △ Slight dirt × Extremely dirt (2) Strength test a, Surface strength test The method of using a wax in the surface strength test method of paper and paperboard described in JIS P 8129 was used. The highest number of waxes that did not damage the paper surface when the wax was peeled was taken as the surface strength. b, Folding strength test MI of paper and paperboard described in JIS P 8115
The bending strength test method using a T tester was followed. The load applied to the test piece was 0.5 kgf.

[0028]

As described above, the present invention has been described in detail. However, according to the method for producing a deinked pulp according to the present invention, the recordability in ink-jet recording is higher than that of the conventional method. Was obtained.

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Claims (4)

[Claims] 1. A method for producing a recording sheet using deinked pulp produced through a plurality of steps including at least a waste paper disintegration step and a deinking step using a surfactant-based deinking agent. A method for producing recording paper, characterized by adding a fine fibrillated cellulose to a raw pulp containing a deinked pulp treated by adding a cationic polymer to at least one of the steps to form a paper. 2. The method according to claim 1, wherein the cationic polymer is an alkylamine.
2. The method for producing a recording sheet according to claim 1, wherein the recording medium is an epichlorohydrin polymer compound or a dimethyldiallylammonium chloride polymer. 3. The method according to claim 1, wherein 0.5 to 15% of the fine fibrillated cellulose is added to the whole pulp. 4. A recording sheet manufactured by the manufacturing method according to claim 1.