JP2001279589A - Method for manufacturing ink-removed pulp and paper containing the ink-removed pulp obtained by the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing ink-removed pulp from newspaper, magazines, copy paper or the like, in which the printing paper produced by compounding the pulp and subjecting the compounded pulp to papermaking process is free from the generation of hair-like ink stains and excellent in printing property when printed with an inkjet-type printer especially using an aqueous ink, and also provide the printing paper. SOLUTION: The method for manufacturing ink-removed pulp comprises a defibring process for waste paper and a successive process using a surfactant- based ink-removing agent. In the method, a sizing agent is added. Another objective paper is made by using the ink-removed pulp.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing deinked pulp produced from newspapers, magazines, copy paper, etc., and to the recording suitability of an ink jet method, particularly an ink jet method using an aqueous ink, containing the deinked pulp. It relates to paper having

[0002]

2. Description of the Related Art Conventionally, deinked pulp is used as a raw material for papermaking together with wood pulp, and is widely used in the fields of newspapers, magazines, copy paper, and the like. A common method for producing deinked pulp is to separate the ink and pulp by washing or flotation, etc., following a waste paper disintegration process, a stirring process such as kneading in the presence of a deinking agent and alkali, and then washing or flotation. )
Thereafter, washing and bleaching are performed as necessary. For example,
Waste paper on which newspapers, magazines, etc. have been printed is disintegrated with an alkaline chemical or the like using a disintegrator such as a pulper, and further an alkaline chemical, hydrogen peroxide and a surfactant are added, and the disintegrated pulp is immersed in these chemicals ( The pulp fibers are swollen by using mechanical agitation together with alkali soaking to separate the ink and the pulp, and then the ink is separated from the pulp by washing or flotation to produce deinked pulp.

Recently, research and development of eco-friendly products (eco-products) have been promoted from the viewpoint of protection of the global environment, and the use of deinked pulp, which is a recycled product, in the paper pulp field is increasing.

According to such a situation, not only ordinary paper, but also the recording paper such as copy paper, the blending ratio of waste paper pulp is increasing, but when the above-described deinked pulp is blended, Feathering (whisker-like bleeding of ink) occurs significantly when recording with an ink jet printer that has become extremely popular with the spread of computers, which makes characters difficult to read and records variable data such as bar codes. In such a case, there is a problem that reading of a barcode or the like becomes difficult. In order to solve this, when making a paper using a pulp slurry containing deinked pulp, a large amount of an internal sizing agent is added, or the surface sizing agent is applied to the surface of the paper using a size press device or the like. Despite the fact that it has been applied, a satisfactory product has not yet been obtained.

[0005]

SUMMARY OF THE INVENTION In view of the above situation, an object of the present invention is to provide an ink jet method, particularly when recording is performed on a paper made by mixing deinked pulp using an aqueous ink as an ink. An object of the present invention is to provide a method for producing a deinked pulp capable of preventing or significantly improving feathering (whisker-like bleeding of ink) and a paper containing the pulp.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found the following method which has never been considered before. That is, in a method for producing a deinked pulp including at least a waste paper disintegration step and a deinking step using a surfactant-based deinking agent, a sizing agent is added to any of the plurality of steps. And a method for producing deinked pulp in the presence of a sizing agent. A more preferred position for adding the sizing agent is the defibration step, and more preferably the sizing agent is added together with the alkaline chemical. The paper containing the deinked pulp thus obtained was free of feathering (whisker-like bleeding of the ink) or significantly improved paper was obtained when recording was performed using an ink jet method, particularly an aqueous ink. .

Although the reason why the above-mentioned object is achieved by the present invention is not necessarily clear, it 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 to make it easier to loosen, and the fibers are rubbed with each other by mechanical stirring to separate the paper into individual fibers. The ink is easily separated and peeled from the fibers in a subsequent deinking process. A surfactant-based deinking agent is added to the disintegrated pulp together with an alkaline chemical, and the ink is separated and separated from the fibers by mechanical stirring or frictional force. Subsequently, the ink separated from the fibers by a washing method or a flotation method is discharged out of the system. Further, if necessary, washing and bleaching are performed to obtain a deinked pulp having a desired whiteness. In the deinked pulp produced by this method, the deinking agent mainly composed of a surfactant is firmly bonded to the fiber surface or penetrates into the fiber. With a degree of washing, the surfactant cannot be completely washed away. When the deinked pulp thus obtained is blended to make paper, even if a sizing agent is internally added as usual or applied (externally added) to the paper surface using a size press device or the like, the fiber The adhesion of the sizing agent to the surface is sufficient. Even if the amount of the sizing agent is increased, the adhesion amount does not increase beyond a certain amount. Therefore, when recording is performed on the paper thus obtained by using the ink jet method, particularly, the aqueous ink, a lot of feathering occurs and the recording quality deteriorates.

On the other hand, according to the present invention, as a result of performing the deinking treatment in the presence of the sizing agent in advance, the sizing agent is sufficiently fixed on the fiber surface. In particular, if the surfactant-based deinking agent is deinked by adding the deinking agent before entering the fiber, that is, after adding the sizing agent in the defibration process, the sizing agent will have a surfactant in the deinking agent. Since there is almost no effect of the sizing agent, it is considered that a sufficient sizing agent is fixed on the surface of the deinked pulp obtained.

The paper containing such deinked pulp can be used as it is, or can be used as a base paper for coating. In particular, when used as an electrophotographic transfer paper, it is possible to preferably respond to the demand for adding a barcode or the like to the electrophotographic transfer paper, which has been increasing in recent years, by aqueous inkjet recording.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The sizing agents usable in the present invention are alkenyl succinic anhydride (ASA) type, alkyl ketene dimer (AKD type), rosin type, styrene type, acrylic type, styrene / acrylic type, olefin type sizing agent. etc,
Known sizing agents can be used. Although the ionicity of the sizing agent to be added can be either anionic or cationic, it is preferable to use a cationic sizing agent rather than an anionic agent when considering fixing of the sizing agent to pulp fibers. .

The amount of the sizing agent is preferably in the range of 0.1 to 5.0% by weight based on 100 parts by weight of waste paper pulp.
In particular, the range of 0.2 to 2.5% by weight is preferable. When the amount of the sizing agent is 0.1% by weight or less based on 100 parts by weight of waste paper pulp, an ink-jet printer or the like using a water-based ink on paper made by mixing the pulp and virgin chemical pulp is used. When recording, feathering tends to increase and the recording quality tends to be inferior. On the other hand, when the amount of the sizing agent added is more than 5.0% by weight with respect to 100 parts by weight of waste paper, the effect of improving feathering is not particularly changed, and the cost is significantly increased. Is not preferred.

The surfactant-based deinking agent of the present invention includes:
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, fatty acid and alkylol amide type, amino acid type, betaine type etc. There are double-sided surfactants and the like, which can be used alone or in combination. Known alkaline chemicals used in the present invention include caustic soda, soda ash, sodium bicarbonate, sodium silicate, and the like. From the viewpoint of handling and cost, it is preferable to use caustic soda. In addition, when an alkaline chemical is used in the defibration step, the addition amount is preferably 1.0% or less with respect to the pulp because the effect of the sizing agent used in combination may be reduced.

The deinked pulp treated in the presence of the sizing agent obtained by the present invention may be used alone or, if necessary, mixed with pulp such as virgin LBKP, NBKP, LBSP or NBSP in an arbitrary ratio. Can be used.

At the time of papermaking, at least the deinked pulp of the present invention is contained, and if necessary, a filler can be internally added. The filler can be appropriately selected from known fillers and used. . Examples of such a filler include talc, kaolin, illite, clay, heavy or light calcium carbonate, and titanium dioxide.
The amount of filler used is usually in the range of 3 to 20% by weight of the filler in paper.

The size of the internal sizing agent used as needed in papermaking is not particularly limited, and any of those commonly used as internal sizing agents in the field of paper can be used. In particular, known internal sizing agents used in copy paper or ink jet recording paper, such as ASA-based, AKD-based, rosin-based, styrene-based, acrylic-based, styrene-acrylic-based, olefin-based sizing agents, etc. One type or two or more types may be selected as appropriate. The addition amount of the internal sizing agent is, for example, usually adjusted in the range of 0.05 to 0.7 parts with respect to the weight of pulp in the case of a rosin-based rosin-modified rosin emulsion sizing agent. Further, if necessary, an antifoaming agent, p
H adjusters, dyes and color pigments for adjusting hue, and fluorescent dyes for improving luminous whiteness can also be used.

Further, a water-soluble polymer can be provided on the paper surface for the purpose of imparting surface strength to the paper. The water-soluble polymer that can be used is not particularly limited as long as it has strong adhesion to paper and does not cause blocking between papers, and oxidized starch, esterified starch, enzyme-modified starch,
Starches such as cationized starch, casein, soy proteins, carboxymethyl cellulose, cellulose derivatives such as hydroxyethyl cellulose, styrene-acrylic resin, isobutylene-maleic anhydride resin, acrylic emulsion, vinegar emulsion, A vinylidene chloride emulsion, a polyester emulsion, a styrene-butadiene latex, an acrylonitrile butadiene latex, or the like can be used alone or in combination, and the amount of the synthetic polymer used is adjusted within a range that does not impair the effects of the present invention.

The above-mentioned water-soluble polymer may be, if necessary, an antifoaming agent, a pH adjuster, a dye or a color pigment for adjusting the hue,
It is provided on the paper surface by applying a coating solution to which a fluorescent dye or the like for improving visual whiteness is added. The coating method may be one-sided, if necessary, using a known coating method such as various size press coating, various blade coating, roll coating, air-knife coating, bar coating, or the like. Alternatively, it can be provided on both sides, but from the viewpoint of operability and cost, it is preferable to use size press coating that can be applied simultaneously on both sides by on-machine. Paper obtained by making paper using the deinked pulp manufactured according to the present invention is particularly effective for ink-jet paper, such as recording paper and printing paper such as electrophotographic transfer paper and thermal transfer paper. Also available.

[0018]

EXAMPLES Hereinafter, the method for producing deinked pulp of the present invention and the specific constitution of paper using the deinked pulp will be described in Examples, and the characteristics of this paper will be compared with Comparative Examples. Although described, the invention is not limited thereby.
In the examples, “%” indicates “% by weight”, and “parts” indicates “parts by weight”. [Example 1] Disintegration processing step 1: Used newspaper and tobacco used paper were mixed in equal amounts by weight ratio, added to an experimental pulper, and 100 parts of the mixed used paper was subjected to a cationic styrene sizing agent (manufactured by Arakawa Chemical Industries, Ltd.). Product name: PM-360) 2.5% and caustic soda 0.
1% was added, and the mixture was diluted to a pulp slurry concentration of 5% and disintegrated.

The waste paper pulp slurry obtained in the defibration treatment step 1 is dehydrated to a concentration of 25%, water is added to the waste paper pulp slurry to a concentration of 15%, and a surfactant-based deinking agent is further added. 1.0% of pulp (manufactured by Kao, trade name: DI-767) was added to the pulp, and the mixture was kneaded with a test kneader for 1 hour, followed by washing and dehydration with a test flotator to obtain a 25% concentration waste paper pulp slurry. Obtained. Subsequently, water is added so that the waste paper pulp slurry concentration becomes 15%, and a surfactant-based deinking agent (manufactured by Kao, trade name: D
I-767) to pulp at 1.0% and bleach at 0.1%.
After adding 5%, kneading with a test kneader for 1 hour, washing and dehydrating with a test flotator, concentration of 25%
Pulp was obtained.

20 parts of the deinked pulp obtained above and a degree of beating of 4
50ml hardwood bleached kraft pulp (L-BKP) 80
Part of pulp slurry, 7 parts of talc, 1 part by weight of aluminum sulfate, sizing agent (Arakawa Chemical Industries, trade name: N
T-76) and 0.12 parts of a yield improver (trade name: High Holder 331, manufactured by Kurita Kogyo Co., Ltd.) were added, and hand-milled. This hand paper was coated with the following coating solution 1 on both sides by a test size press, and the coating amount per side was 1.
Coating was performed so as to be 5 g / m ² to obtain paper having a basis weight of 82 g / m ² . <Coating liquid 1> Starch: MS # 3600 (manufactured by Nippon Shokuhin Kako Co., Ltd.) 100 parts Sizing agent: Polymalon 482 (manufactured by Arakawa Chemical Co., Ltd.) 0.4 parts Antifoaming agent: Nopco 8034L (manufactured by San Nopco) 0.09 parts [ example 2 except that defibration step 1 cationic styrene sizing agent was 0.1% was obtained paper of example 1 in the same manner as basis weight 82 g / m ^2. Example 3 A paper having a basis weight of 82 g / m ² was obtained in the same manner as in Example 1 except that the cationic styrene sizing agent in the disintegration step 1 was changed to 5.0%. [Example 4] An anionic styrene / acrylic sizing agent (Arakawa Industry, trade name: PM)
-1343), and a paper having a basis weight of 82 g / m ² was obtained in the same manner as in Example 1 except that the addition amount was changed to 0.2%. Example 5 A paper having a basis weight of 82 g / m ^{2 was} prepared in the same manner as in Example 1 except that the sizing agent in the disaggregation step 1 was changed to an anionic styrene-acrylic sizing agent, and the amount added was changed to 2.5%. I got Changing the Example 6 sizing agents of the macerating step 1 to rosin sizing agent, except that the added amount of 2.5% was obtained paper of Example 1 in the same manner as basis weight 82 g / m ^2. [Example 7] Disintegration treatment step 2: Newspaper wastepaper and leaflet wastepaper were mixed in equal amounts by weight ratio, 100 parts of this mixed wastepaper was added to an experimental pulper, and 0.1% of caustic soda was added. Was diluted by adding water so as to be 5%.

The waste paper pulp slurry obtained in the defibration treatment step 2 was dehydrated to a concentration of 25%, and then water was added to a waste paper pulp slurry concentration of 15%. Next, 0.1% of a cationic styrene-based sizing agent (trade name: PM360, manufactured by Arakawa Chemical Industries) is added to the pulp and stirred, and then a surfactant-based deinking agent (trade name, manufactured by Kao, trade name: DI7
67) was added to the pulp at 1.0%, and the mixture was kneaded with a test kneader for 1 hour, followed by washing and dewatering with a test flotator to obtain a wastepaper pulp slurry having a concentration of 25%. Subsequently, water was added so that the waste paper pulp slurry concentration became 15%, and further the deinking agent was added to the pulp at 1.0%.
% And a bleaching agent 0.5%, and after kneading with a test kneader for 1 hour, washed and dehydrated with a test flotator to obtain a deinked pulp having a concentration of 25%.

[0022] 20 parts of the deinked pulp obtained above and beating degree 4
50ml hardwood bleached kraft pulp (L-BKP) 80
Part of pulp slurry, 7 parts of talc, 1 part of aluminum sulfate, 0.1 part of sizing agent (manufactured by Arakawa Chemical Industries, trade name: Size Pine NF76), and retention agent (manufactured by Kurita Industries, Ltd.)
Trade name: High holder 331) 0.02 part was added and hand-grained. The hand-made paper was coated with a coating solution 1 shown below on both sides by a test size press such that the coating amount per side was 1.5 g / m ^{2 in} solid content, and the basis weight was 82 g / m ^2.
to obtain a paper m ^2. Comparative Example 1 A paper having a basis weight of 82 g / m ² was obtained in the same manner as in Example 1 except that the sizing agent was not added in the disintegration step 1 (addition amount: 0%). [Comparative Example 2] No sizing agent was added in disintegration step 1,
A paper having a basis weight of 82 g / m ² was obtained in the same manner as in Example 1 except that the sizing agent of the coating liquid 1 was changed to 0.8 part.

An ink jet recording test of the recording papers obtained in Examples 1 and 2 was performed by the following method.

The results are summarized in Table 1. From Table 1, it can be seen that Examples 1 to 7 of the present invention have good feathering and ink drying properties, whereas the paper of Comparative Example 1 prepared with only a small amount of internal and external addition sizes was used. Feathering is poor, even in Comparative Example 2 in which the internal sizing agent was increased to 0.8 part, compared to Example 4 using deinked pulp that was deinked in the presence of a smaller sizing agent.
Feathering is very bad.

[0025]

[Table 1] (1) Inkjet recording test The recording test was performed using an inkjet printer (BJC-430).
J: trade name, manufactured by Canon Inc.), and a predetermined pattern was recorded, and evaluated according to the following criteria. a, Feathering (whisker-like bleeding of ink) Whisker-like bleeding of the ink was visually evaluated. ○ No whisker-like bleeding, △ Slight whisker-like bleeding, × Many whisker-like bleeding, b, ink drying property Immediately after recording, the image area was rubbed with a finger, and the degree of dirt was visually evaluated. ○ No dirt △ Slightly dirt × Extremely dirt

As described above, the present invention has been described in detail. However, by using the deinked pulp according to the present invention, the feathering in the case of aqueous ink jet recording was remarkably improved, and could not be achieved by the conventional method. Paper having high quality recording properties was obtained.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4L055 AA11 AE02 AE04 AE05 AE10 AG50 AG63 AG71 AH10 BA11 BA16 BA37 BB06 EA32 FA17 FA30 GA09

Claims (4)

[Claims] 1. A method for producing a deinked pulp comprising at least a waste paper disintegration step and a deinking step using a surfactant-based deinking agent, wherein a sizing agent is added to any of the plurality of steps. And a deinking treatment in the presence of a sizing agent. 2. The method for producing deinked pulp according to claim 1, wherein a sizing agent is added in the step of disintegrating the used paper. 3. The method for producing deinked pulp according to claim 1, wherein the amount of the sizing agent is in the range of 0.1 to 5.0% by weight based on 100 parts by weight of waste paper pulp. Method. 4. Paper using the deinked pulp produced according to claim 1.