JP2001081691A - Newsprint paper for offset printing - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide newsprint paper for offset printing containing a high proportion of waste paper pulp (DIP), and particularly to effectively prevent vessel pick trouble during offset printing and to cause blanket piling and the like. To provide newsprint paper for offset printing which is excellent in printing workability. A newspaper for offset printing obtained by applying and drying a surface treatment agent on the surface of a base paper, wherein the surface treatment agent comprises an aqueous composition containing a phosphate esterified starch as a main component. Paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to newsprint, particularly newsprint containing a high percentage of waste paper pulp (DIP), which effectively prevents vessel pick trouble during offset printing and does not cause blanket piling or the like. The present invention relates to newsprint paper for offset printing having excellent printing workability.

[0002]

2. Description of the Related Art In recent years, offset printing, color printing, and high-speed newspaper printing have been rapidly advanced. Along with that, newsprint paper that is a printing medium is required to have even better color printability and print workability. Conventionally, newsprint paper is mainly made of mechanical pulp or waste paper pulp. It has been requested. By the way, waste paper raw materials used in the production of newsprint are mainly composed of old newsprint, and a large number of leaflets containing hardwood pulp such as uncoated paper and coated paper are mixed in addition to the old newsprint. When such used paper is used as a papermaking raw material for newsprint, as the blending amount of the used paper pulp increases, a vessel (conduit) peculiar to hardwood pulp comes to be more and more mixed into the manufactured newsprint. As a result, the vessels scattered near the surface of the newsprint are peeled off from the paper surface during printing, causing white spots (vessel picking) in the printed image, which causes printing troubles such as blanket piling. And the printing quality deteriorates.

[0003] Offset printing is a method in which dampening solution and printing ink are supplied to a printing plate, and then the ink is transferred to a rubber plate called a blanket, and then transferred to paper for printing. In order to use a printing ink having a relatively high tack compared to a printing method, a paper having a high surface strength is required. If the surface strength is weak, fibers and fillers released from the paper due to paper peeling etc. become paper powder and accumulate on the blanket, so-called blanket piling,
When they are mixed with the ink, so-called blurring or the like occurs on the printing surface of the paper surface, causing troubles such as a decrease in print quality and a decrease in print workability. In particular, the troubles of the vessel picking described above occur in a relatively short time from the start of printing as compared with blanket piling due to paper dust, filler, etc. There is a problem that not only the printing workability is significantly reduced but also the printing quality is lowered.

[0004] As a method for solving various problems caused by the decrease in surface strength during offset printing as described above, conventionally, a high-molecular material such as starch, PVA, polyacrylamide, or the like is used as a component on the surface of newsprint. It is common practice to apply a surface treatment agent. Compared with fine fibers and fillers scattered near the surface layer of paper, much coarser vessels do not cause picking during printing, and in order to maintain a state of staying on the paper surface, the surface described above must be used. It is a general prescription to increase the amount of the treatment agent used and to prevent the vessel from falling off. On the other hand, when the amount of the surface treatment agent as described above is increased, not only the cost is increased, but also the paper surface tends to exhibit adhesiveness called "Nepari property" when the paper surface is wet. When the slimness increases, the blanket piling particularly in the non-image area may be increased, or the paper surface may stick to the blanket during printing, resulting in running troubles such as wrinkles and paper breaks. Not preferred. Among these surface treatment agents, starch and polyacrylamide are widely used due to their relatively low nepari properties, but all of them have high solubility in water, so they are easily dissolved in dampening water during printing. There is a drawback that the material is easily deposited on the blanket together with the filler and the filler, and so-called blanket piling is easily caused.

[0005] In view of the above situation, various methods have been conventionally proposed, especially for the problem of vessel picking. For example, JP-A-6-220790 discloses a method of treating a pulp slurry containing hardwood with a kneader at a high concentration, and JP-A-10-266090 discloses a printing paper or coated printing base paper containing ozone-treated hardwood pulp. JP-A-10-273897 proposes a coated paper or the like containing a specific styrene-butadiene copolymer latex and starch. However,
In the above proposals, equipment costs are high and the cost is high, so that it is difficult to apply to waste paper pulp, or as in newsprint, relatively low U.S.P., and more than 40% by weight of waste paper pulp is blended. In such high-rate compounded products, the measures against vessel picking have not yet been sufficiently satisfied.

[0006]

SUMMARY OF THE INVENTION Under the circumstances described above,
The present inventors have intensively studied and studied a formulation that suppresses the occurrence of vessel picking and paper dust during offset rotary printing, particularly in newsprint containing a high percentage of waste paper pulp, and enables a stable printing operation. . As a result, the present invention is to provide newsprint paper for offset printing which improves the resistance strength of paper to a vessel pick efficiently with a small amount of application of a surface treating agent, and is excellent in printing quality and printing workability.

[0007]

According to the present invention, there is provided an offset printing newsprint obtained by applying a surface treating agent to the surface of a base paper and drying the same, wherein the surface treating agent is mainly composed of a phosphorylated starch. Newsprint paper for offset printing characterized by comprising an aqueous composition. Further, the present invention includes the following embodiments. That is, the above-described newsprint paper for offset printing using a base paper containing aluminum sulfate as the base paper, and the coating amount of the phosphate esterified starch is 0.05 to 0.7 g / m ² per one side in dry weight. This is newsprint paper for offset printing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, newsprint paper for offset printing has conventionally been generally coated with a surface treating agent mainly composed of starch, PVA, polyacrylamide, or the like. I have. Each of these surface treatment agents has a certain effect in suppressing the generation of paper dust, but in order to prevent vessel picking, it is necessary to increase the application amount. As a result, another problem such as an increase in the nappiness occurs, and in actuality, in a continuous printing for a long time, a satisfactory result is not always obtained.

The present inventors have reviewed and studied the types of starch as a surface treating agent. as a result,
The use of phosphate esterified starch, in particular,
The improvement of surface strength, which is a measure against vessel picking of newsprint containing a lot of P (deinked waste paper pulp), can be remarkably exhibited.
As a result, they found that blanket piling at the time of offset printing can be reduced and the nepari property can be effectively reduced, and the present invention has finally been completed. The reason why the use of the phosphorylated ester starch effectively suppresses the vessel picking and reduces the Neppari property is not necessarily clear, but is presumed as follows.

That is, like ordinary newsprint base paper, aluminum sulfate [Al ₂ (SO ₄ ) ₃ ] is contained in the base paper, and the acid-formed paper is coated with the phosphorylated starch and dried. As a result, the phosphate groups of the phosphate esterified starch have aluminum ions (A
l ³⁺ ), synergistically improves the adhesive strength of the phosphate esterified starch coating, effectively prevents vessel picking with a smaller coating amount, and reduces the amount of starch in combination with the lower starch amount. It is estimated to be reduced.
In addition, among the phosphorylated esterified starches, those having a reduced viscosity are particularly easy to penetrate into the inside of the paper layer when applied to the paper surface, and the effect of improving the strength as a whole is obtained. This is a desirable mode because it acts more effectively on

The starch raw material for obtaining the phosphate esterified starch is not particularly limited, and conventionally known and used starch raw materials are used. For example, untreated starch such as corn, potato, tapioca, wheat, rice and the like, and starch subjected to oxidation treatment and the like can be mentioned. In addition, the surface treatment agent mainly composed of phosphate esterified starch, other adhesives as appropriate as long as the initial effect of the present invention is not impaired, for example, modified starches, latexes such as styrene-butadiene copolymer, Pigments such as polyvinyl alcohol and polyacrylamide, as well as kaolin and calcium carbonate, can also be added. It is necessary that the amount of the phosphate esterified starch in the surface treatment agent accounts for at least 30% by weight of the total solid content. By the way, if it is less than 30% by weight, there is a possibility that the effects desired by the present invention may not be obtained. Further, various assistants such as an antifoaming agent, a waterproofing agent, a surface sizing agent and a preservative are added to the surface treating agent (coating liquid) as required. The solid content concentration of the surface treatment agent is not particularly limited, but is appropriately adjusted depending on a coating device and a target coating amount, but is usually 2 to 15% by weight.

The surface treating agent prepared as described above can be applied to a coating apparatus generally used in the papermaking field, for example, a size press, a blade metalling size press, a rod metaling size press, a gate roll coater, a blade coater, a bar coater, The material is applied to the surface of the base paper using a device selected from known and publicly used devices such as a rod blade coater and an air knife coater. The amount of the surface treatment agent applied by using such an apparatus is not particularly limited, but it is preferably as small as possible in consideration of operability, nepari property, cost, etc. The amount of phosphorylated starch is 0.05-
It is adjusted in the range of 0.7 g / m ² . By the way, 0.05g
If it is less than / m ^2, the effect of improving the resistance to the vessel pick and surface strength becomes insufficient, exceeds the other 0.7 g / m ^2, not only the high cost, increased Neppari, etc. are concerned You. After the surface treating agent is applied and dried, the product is passed through a calender as needed, and is pressed and smoothed to finish the product. As a calender device in such a case, using a soft calender having a metal roll / resin roll configuration as compared to a machine calender using a normal metal roll / metal roll combination does not strongly press the base paper layer. This is a more preferred embodiment because it can be smoothed and can further suppress a decrease in paper layer strength.

Next, as pulp constituting the base paper,
Chemical pulp (bleached or unbleached NKP or LKP
), High yield pulp (GP, CGP, RGP, PG
W, TMP, etc.), waste paper pulp (DIP) and the like are used in an arbitrary ratio. In the papermaking, if necessary, an amorphous silica-based inorganic pigment such as white carbon, calcined kaolin, structured kaolin, and titanium dioxide, and further a papermaking filler such as urea-formaldehyde resin are added to the stock. can do. Furthermore, in the stock, aluminum sulfate, paper strength agent,
A generally known papermaking chemical such as a retention aid, a sizing agent such as a strengthened rosin sizing agent or an emulsion sizing agent, a water-proofing agent, or an ultraviolet ray inhibitor is added, and acidic papermaking is performed with a normal papermaking machine. Further, even in the case of neutral papermaking, base paper which is made by adding a small amount of aluminum sulfate internally is also preferably used. The basis weight of the base paper is not particularly limited, but is usually in the range of about 30 to 50 g / m ² .

[0014]

EXAMPLES The present invention will be specifically described below with reference to examples. Of course, the present invention is not limited to these examples. Parts and% in Examples are parts by weight and% by weight, respectively, unless otherwise specified.

Example 1 (Preparation of base paper) Softwood kraft pulp (NKP) 14
Pulp slurry consisting of 40 parts, 40 parts of thermomechanical pulp (TMP), 7 parts of ground pulp (GP), and 39 parts of newspaper deinked waste paper pulp (DIP) is beaten with a refiner to prepare a pulp slurry having a freeness (csf) of 110 ml. did. On the pulp slurry obtained in this way,
0.3% of rosin emulsion size (trade name: SPN-773 / Arakawa Chemical Industry Co., Ltd.), 1% of aluminum sulfate, and 1% of white carbon having an average particle diameter of 15 μm are added to and mixed with pulp solid content, and mixed. A preparation was prepared. Next, papermaking was performed using the paper material using a twin-wire type paper machine to obtain a base paper having a rice area of 40 g / m ² .

(Preparation of Newsprint Paper) As a surface treatment agent, water was added to a phosphate-esterified corn starch (trade name: P-140 / Oji Cornstarch Co., Ltd.) having a solid content of 25%, which was dissolved by heating with hot water. A surface treatment agent having a concentration of 10% was prepared. Next, this surface treatment agent was applied to both sides of the base paper obtained above using a gate roll coater so that the dry weight was 0.2 g / m ² per side, and then dried. Nip processing was performed to obtain newsprint paper for offset printing.

Example 2 In Example 1, the surface treating agent was changed to a phosphorylated ester of potato starch (trade name: Neil Gum A-85 / Abebe Co.). A newsprint was obtained in the same manner as in Example 1 except that the coating was performed so as to be 0.3 g / m ² per one side and dried.

Example 3 In Example 1, 70 parts of a phosphorylated corn starch (P-140 / the above) and an oxidized starch having a solid content of 25% dissolved by heating with hot water (trade name: Ace A / Oji Cornstarch) 30 parts (each
(In terms of solid content), and water was added to the solution to prepare a surface treating agent having a solid content of 12%. Then, using this surface treating agent, the dry weight is 0.3 g per side.
/ M ² , except that coating and drying were performed in the same manner as in Example 1 to obtain newsprint.

Example 4 In Example 1, as a surface treating agent, 80 parts of a phosphorylated corn starch (P-140) and polyvinyl alcohol having a solid content of 10% (trade name: PVA117 / A solution of 20 parts (Kuraray Co., Ltd., each in terms of solid content) was prepared as a mixed solution, and water was added to the solution to prepare a surface treatment agent having a solid content of 9%. Next, newsprint paper was obtained in the same manner as in Example 1 except that the surface treatment agent was applied and dried so that the dry weight was 0.3 g / m ² per one side.

Comparative Example 1 In Example 1, the surface treating agent was oxidized corn starch (trade name: Ace A / Oji Cornstarch Co., Ltd.), the solid content concentration was 11%, and the applied amount was 0.3 g / dry weight per side. m ² except that it was applied and dried.
Newsprint paper was obtained in the same manner as in Example 1.

Comparative Example 2 Comparative Example 1 was conducted in the same manner as in Comparative Example 1 except that the solid content was 13% and the amount of the surface treatment agent applied was 0.5 g / m ² per one side in terms of dry weight, and then dried. In the same manner as in Example 1, newsprint was obtained.

Comparative Example 3 In Example 1, the surface treatment agent was polyacrylamide (trade name: Santax NP-14 / Mitsui Chemicals), the solid content concentration was 10%, and the amount of the surface treatment agent applied was dry weight. A newsprint was obtained in the same manner as in Example 1 except that the coating was performed so that the weight per one side became 0.4 g / m ^2, and then dried.

Comparative Example 4 In Example 1, the surface treatment agent was polyvinyl alcohol (trade name: PVA117 / Kuraray Co.), and the solid content was 8
%, And the newspaper was obtained in the same manner as in Example 1 except that the surface treatment agent was applied and dried so that the applied amount of the surface treating agent was 0.2 g / m ² per one side in dry weight.

With respect to the newsprints obtained in the examples and the comparative examples thus obtained, the following quality evaluations were performed, and the obtained results are shown in Table 1.

(Blanket Piling) Using an offset printing machine (Komori SYSTEM-20 / Komori Corporation), printing was performed in continuous four-color printing of 5,000 copies, and then the accumulation of paper dust in the blanket non-image area was performed. The degree was visually determined. : No generation of paper dust was observed. Δ: Generation of paper powder is slightly observed. ×: A lot of paper powder is deposited on the blanket.

(Vessel Pick) Offset rotary printing ink (black ink) having a dot area ratio of 30 to 100% using an offset printing machine (Komori SYSTEMC-20 / above).
Was performed, and the degree of white spots due to a vessel having a solid area percentage of 100% was visually determined. : Almost no white spots were observed. Δ: White spots are slightly observed. ×: Many white spots occur.

(Nappari property) Two newsprint samples were cut to a suitable size, immersed in water for 10 seconds, brought into close contact with each other, passed through a calender at a linear pressure of 100 kg / cm, and allowed to stand at room temperature for 24 hours. After drying, the peel strength of the two sheets of paper was measured using a tensile tester. The larger the value, the greater the tackiness (Nepari property).

[0028]

[Table 1]

[0029]

As is clear from Table 1, the newsprint for offset printing according to the embodiment of the present invention has extremely low occurrence of vessel picking and blanket piling.
In addition, the paper was excellent in offset printability.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuhiro Nojima 4-3-1 Jokoji, Amagasaki City, Hyogo Prefecture Oji Paper Co., Ltd. Amagasaki Research Center F term (reference) 4L055 AC09 AG08 AG48 AH09 AH13 BE08 EA14 FA13 FA15 GA16

Claims (3)

[Claims] 1. An offset printing newsprint obtained by applying and drying a surface treating agent on the surface of a base paper, wherein the surface treating agent comprises an aqueous composition containing a phosphate esterified starch as a main component. Newspaper for offset printing. 2. The offset printing newsprint according to claim 1, wherein the base paper contains aluminum sulfate. 3. The newsprint paper for offset printing according to claim 1, wherein the coating amount of the phosphorylated ester is 0.05 to 0.7 g / m ² per one side in dry weight.