JPH0593392A - Mechanical paper for printing - Google Patents

Abstract

PURPOSE:To obtain the subject mechanical paper, having glossiness within a prescribed range, excellent in white paper glossiness, printed surface quality and printing operation efficiency and suitable for offset multicolor printing, etc., by applying a clear sizing coating onto a specific paper substrate. CONSTITUTION:The objective mechanical paper is obtained by applying a clear sizing coating layer onto at least one surface of a paper substrate containing mechanical pulp and/or deinked waste paper pulp in an amount of 50-80wt.% in the total pulp component with 5-25wt.% ash content (JIS P-8128) so as to provide 0.2-1.5g/m<2> coating amount. The glossiness of the coated surface is 15-25%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium-quality paper for printing, and more specifically, it is suitable for use in a heat set type offset printing machine capable of obtaining a good printing effect even in multicolor printing and also for gravure printing. The present invention also relates to a suitable medium-quality printing paper having a clear-size coating layer on the surface of the medium-quality paper.

[0002]

2. Description of the Related Art The demand for printing papers having excellent printing finish and sharpness is remarkably increasing, and their applications are expanding in various fields. Especially in recent years, there has been a strong tendency toward colorization and visualization.
This tendency has also reached magazines, leaflets and newspaper inserts that publish large numbers of copies.

It is necessary to design the printing paper for these uses in a well-balanced manner in order to meet various needs such as low cost, excellent workability of offset printing, excellent printing surface quality, light weight and high opacity. There is. As a printing paper with improved printing finish and definition in offset printing, inorganic or organic pigments such as coated paper, art paper, cast coated paper, medium coated paper, and lightly coated paper are coated on a base paper for support together with an adhesive. Known coated paper is known, but these coated papers have problems in complexity of the manufacturing process, manufacturing efficiency, and operation efficiency even if the printing surface quality is good, and they are also required in terms of cost reduction. There is a problem that it does not match. On the other hand, there is a demand for printing paper that can be printed by both the offset printing machine and the gravure printing machine in order to correct the uneven operating rate of the printing machine. There is no such thing.

On the other hand, among offset printings, a large amount of printing papers not coated with pigments, which achieves a low printing cost while ensuring a printing surface quality to some extent, such as newspaper offset printing. However, these printing papers are unsuitable for gravure printing because of the sharpness of the printed surface and the low glossiness of the printed matter, and are differentiating from other competing products that are required for high-quality products or leaflets, advertisements, etc. At present, however, it is not satisfactory.

Further, when a surface treatment is performed with a calender such as a machine calender or a super calender in order to obtain a beautiful printed matter having a high gloss, there is a problem that the desired gloss is hardly achieved.

Further, even if the paper support is surface-treated by the above-mentioned calendering device under stronger treatment conditions, in this case, the pulp fibers constituting the paper support are crushed or rubbed so that the pulp fibers constituting the paper support are crushed or rubbed. By breaking, binding of pulp fibers, breaking of entanglement,
The fibers on the surface of the paper support are damaged, and the phenomenon of a decrease in surface strength occurs.

When this excessively calendered paper support is printed by an offset printing machine, a so-called picking phenomenon occurs, and there is a problem that it adheres to or deposits on a blanket of the printing machine and impairs the printing surface quality.

As described above, in so-called non-coated paper in which a coating layer containing an inorganic or organic pigment is not provided on a paper support, glossiness and smoothness are improved by a calender device such as a machine calender or a super calender. Although it is possible to do so, there is the drawback that the surface strength is reduced.

In order to improve the surface strength of this paper support, polyvinyl alcohol (PVA), starch, polyacetic acid can be applied with a coating machine such as a double roll size press, a gate roll coater, a bell papa blade coater or a short dwell coater. It is generally considered to apply a size coating solution such as vinyl or styrene-butadiene copolymer.

However, when these size coating solutions are applied, gloss and smoothness are often difficult to develop and the surface strength is improved, but the surface strength tends to decrease as the calendering treatment is strengthened. There is no change. Also, when a large amount of these size coating solutions is applied, the opacity decreases,
Since the tensile strength is reduced, the purpose cannot be achieved only by applying the size coating solution.

On the other hand, as a method for improving glossiness and smoothness of a paper support subjected to calendering,
Inorganic fillers such as talc, calcium carbonate, hydrous silicate,
It is possible to improve smoothness and glossiness even under the same calendering conditions by internally adding organic filler made of synthetic resin such as urea formalin resin and polystyrene to the paper, but on the other hand, these fillers are included. Has a drawback that the tensile strength, tear strength, and surface strength of the paper are significantly reduced due to its weak binding force with pulp fibers.

Therefore, the conventional technique has a problem in that it is impossible to produce an uncoated paper which can give a printed surface quality as close as possible to a coated paper, and its development has been desired.

[0013]

SUMMARY OF THE INVENTION The present invention provides a clear size coating layer on a paper support without providing a coating layer containing a pigment on the paper support. Medium quality paper for printing, which uses medium quality paper mainly composed of waste paper pulp and has a pigment coating layer on the medium quality paper and has white paper glossiness, printing surface quality and printing workability comparable to that of medium quality coated paper. The purpose is to provide.

In view of the above-mentioned problems, the present inventors completed the present invention as a result of multi-faceted examination of pulp blending, filler blending, clear size coating amount and calendering conditions of medium quality paper.

[0015]

According to the present invention, 50-80% by weight of all pulp components is mechanical pulp and / or deinked waste paper pulp, and the ash content (JIS P-8128) is 5-25% by weight. %, A clear size coating layer is coated on at least one side of 0.2 to 1.5 g / m ² on a paper support, and the glossiness of the coated surface is 15 to 25%. It is a medium quality paper.

The mechanical pulp used in the present invention includes pressurized stone ground pulp (PGW), thermomechanical pulp (TMP) and stone ground pulp (G).
P), refiner ground pulp (RGP), and other mechanical pulps.

The deinked waste paper pulp (DIP) used in the present invention includes the above-mentioned PGW, TMP, GP and R.
There is DIP deinked from newspaper printing waste paper and medium quality printing waste paper containing at least one kind of mechanical pulp such as GP.

In the present invention, 50 to 50% of all pulp components are used.
It is necessary to contain 80% by weight of mechanical pulp and / or deinked waste paper pulp, and the preferable content is 65-80% by weight.
Is. The remaining 50 to 20% by weight is soda pulp (AP), sulfite pulp (SP), kraft pulp (K
P) and other chemical pulps.

The above-mentioned mechanical pulp and DIP are used alone or as a mixture to make paper. The mixing ratio in the case of mixing mechanical pulp and DIP for papermaking is about 5 to 80 parts by weight of DIP with respect to 100 parts by weight of mechanical pulp.
The most preferred mechanical pulp used in the present invention is pressure stone ground pulp (PGW). This PG
Since W does not contain a bundle in the pulp fiber and is flexible and is fibrillated, the smoothness and surface roughness of the paper support are improved by using this PGW. Stone ground pulp (GP) is also preferably used.

Incidentally, regarding mechanical pulp (mechanical pulp), Paper Pulp Gijutsu, Vol. 41, No. 10 (1987).
(October, 2010), pages 14-25.
Regarding the properties of PGW, Pulp and Paper Journal, 40th
Volume 11 (July 1986), pages 9-19.

These mechanical pulps and / or DIPs are blended in an amount of 50 to 80% by weight based on the total pulp components. If they are blended in excess of 80% by weight, printing is performed when a clear size coating layer is provided on the paper support. Although the aptitude improves,
The paper strength represented by the tensile strength, tear strength and burst strength of paper is reduced.

When the mechanical pulp and / or DIP content in the total pulp is less than 50% by weight, the paper strength is satisfactory when a clear-size coating layer is provided on the paper support, but the glossiness is high. Is difficult to develop, and the opacity decreases.

In the present invention, the remaining 20 to 50% by weight of pulp to be blended with mechanical pulp and / or deinked waste paper pulp is chemical pulp, and preferred one is kraft pulp (KP), Is preferably a softwood (N material). Chemical pulp is blended in unbleached, semi-bleached or bleached pulp according to the quality design.

The paper support used in the present invention is blended with the above pulp so that the ash content of the paper is 5% to 25% by weight, preferably 10 to 20% in a conventionally known paper machine. Talc, calcium carbonate,
Kaolinite clay, hydrous silicate and other paper fillers are added, and if necessary, sulfuric acid bands, sizing agents, paper strength enhancers, retention aids, pigments, colorants, fluorescent dyes, defoamers and Other paper-making chemicals are added to make paper as acidic paper or neutral paper.

In the present invention, a clear size coating layer is further provided on the paper support, and this coating layer is starch, oxidized starch, esterified starch, etherified starch, cationized starch, enzyme-modified den powder, etc. Modified den powder, cellulose derivatives such as carboxymethyl cellulose, hydroxyethyl cellulose and methyl cellulose, polyvinyl alcohol, carboxyl modified polyvinyl alcohol, modified polyvinyl alcohol such as acetoacetylated polyvinyl alcohol, styrene-maleic anhydride copolymer, styrene-butadiene copolymer Coated, an aqueous solution containing an adhesive selected from polyvinyl acetate, a vinyl chloride-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, polyacrylic acid ester, etc., or an aqueous latex. That.

The coating amount is 0.2 to 1.5 g / m ² on at least one side of the support. When it is applied to both sides of the paper, it is necessary to apply each to 0.5 to 1.5 g / m ² , preferably 0.8 to 1.0 g.
/ M ² It is applied in the range.

Further, it is of course possible to appropriately add various auxiliaries such as a dispersant, a flow modifier, an antifoaming agent, a dye, a lubricant, a water-proofing agent and a cross-linking agent to the clear size coating solution, if necessary. ..

In the present invention, the clear size coating solution is a conventionally known two roll size press, an air knife coater, a roll coater, a gate roll coater, or a blade coater in which the blade is a hebel and a vent type coater. Coating is performed on-machine or off-machine with various coating devices such as bill blades and twin blades.

In the present invention, the clear size coating layer has a glossiness (JIS P-8142) of 15 to maintain the properties suitable for offset printing multicolor printing.
It should be in the range of 25%, preferably 20-25%. When extreme conditions are selected so that the glossiness exceeds 25%, the surface strength of the clear size coated surface becomes weak. Further, when the glossiness is less than 15%, it is difficult to obtain a beautiful color print which is the object of the present invention.

In order to obtain the above-mentioned gloss of 15 to 25%, it is necessary to surface-treat the clear size coated surface with a calendar device such as a machine calendar or a super calendar.
Total nip pressure of 1400 to 2 in step 11 nip paper passing process
It is preferable to impart glossiness at 000 Kg / cm.

The basis weight of the paper support is in the range of 35 to 65 g / m ² , the thickness is 42 μm to 70 μm, and the basis weight as a product is 3
Those in the range of 5.4 to 70 g / m ² are preferable.

Further, in order to obtain whiteness, opacity, smoothness, surface strength, and glossiness in accordance with quality design, pulp blending, filler blending, adhesive blending, and calendering conditions can be appropriately changed. Needless to say.

[0033]

EXAMPLES The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. The parts and% in the examples and comparative examples are parts by weight and% by weight, unless otherwise specified. The pulp used in Examples and Comparative Examples has the physical properties shown in Table 1 below.

[0034] * 1 Measured according to JIS P-8121 * 2 Adjusted according to JIS P-8209, JIS P-81
Measured at 18

Example 1 Radiator pine (New Zealand) material TMP1
An internal additive sizing agent (SPG, manufactured by Arakawa Chemical Co., Ltd.) was added to 100 parts of a pulp composition consisting of 5 parts, 15 parts of GP, 35 parts of PGW and 35 parts of NBKP (all parts by weight of absolutely dry pulp).
Parts, 1.0 parts of sulfuric acid band, and 20 parts of talc were added to prepare a pulp slurry having a concentration of 1.5% by using a paper machine capable of making newsprint paper with a basis weight of 54.2 g / m ² and a thickness of 57 μ.
A paper support having m and an ash content of 16% was produced.

On the other hand, steamed oxidized starch (Oji Ace, manufactured by Oji Constarch Co., Ltd.) was adjusted to a concentration of 6.8%, and the coating amount on both sides was 1.0 g / m ² at 980 m / min using an on-machine blade coater. The coating was carried out so as to obtain a supercalendering treatment under the conditions of a sheet passing speed of 500 m / min, a total nip pressure of 1900 kg / cm and a bottom nip pressure of 240 kg / cm. The total nip pressure is the total nip pressure of the rolls applied to the paper. Table 2 shows the results of the physical property test of the starch-coated paper. The glossiness was 22.0%, the surface strength of the paper was strong, and good offset printing paper and gravure printing paper were obtained.

Example 2 Radiator pine material TMP 15 parts, GP 20 parts, PG
In a pulp composition consisting of 35 parts of W and 35 parts of NBKP, a sizing agent, a sulfuric acid band, and talc were added in the same manner as in Example 1 to obtain a basis weight of 54.2 g / m ² , a thickness of 57 μm, and an ash content of 1
A 7% paper support was made into paper.

On the other hand, polyvinyl alcohol (Gosenal manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was used as the adhesive and steamed.
It was adjusted to a concentration of 5% and was coated on-machine using a blade coater at 980 m / min so that the coating amount on both sides would be 0.5 g / m ² , and was supercalendered under the same conditions as in Example 1. .. Table 2 shows the results of the physical property test. The glossiness was 24%, the surface strength of the paper was strong, and good offset printing paper and gravure printing paper were obtained.

Example 3 The pulp composition, the sizing agent, and the amount of sulfuric acid band added to the paper support were the same as in Example 1, except that the amount of internally added talc was changed, and the basis weight was 54.2 g / m ² . A paper support having a thickness of 58 μm and an ash content of 20% was produced.

On the other hand, the adhesive was applied under the same conditions as in Example 1 so that the coating amount on both sides would be 0.6 g / m ² , then the paper feeding speed was 500 m / min, the bottom nip pressure was 200 kg / cm,
Super calendering was carried out under the condition of a total nip pressure of 1500 kg / cm. Table 2 shows the results of the physical property test. Gloss is 2
At 3.0%, the surface strength of the paper was strong, and good offset printing paper and gravure printing paper were obtained.

Example 4 Radiator pine material TMP 15 parts, GP 15 parts, PG
In a pulp composition consisting of W35 parts, DIP5 parts and NBKP30 parts, in the same manner as in Example 1, a sizing agent and a sulfuric acid band were added, and only the addition amount of the internally added talc was changed to obtain a basis weight of 54.2 g / m ² , A paper support having a thickness of 57 μm and an ash content of 18% was produced.

On the other hand, the coating solution was prepared in the same manner as in Example 1,
The coating was carried out so that the coating amount on both sides was 1.2 g / m ² , and super calendar treatment was carried out under the same conditions as in Example 3.
Table 2 shows the results of the physical property test. The glossiness is 22.6%,
The surface strength of the paper was strong, and good offset printing paper and gravure printing paper were obtained.

Comparative Example 1 An offset printing paper was manufactured under the same conditions except that the starch coating of Example 1 was not carried out and that no sizing agent was added. Table 2 shows the results of the physical property test. Gloss is 2
Although it is as good as 6.5%, the surface strength is weak and it is unsuitable as an offset paper.

Comparative Example 2 An offset printing paper was manufactured under the same conditions except that the coating solution of Example 4 was not applied, and no sizing agent was added. Table 2 shows the results of the physical property test. Gloss is 2
Although it is as good as 5.5%, the surface strength is weak and it is unsuitable as an offset paper.

Comparative Example 3 In a pulp composition consisting of 15 parts GP, 50 parts PGW and 35 parts NBKP, a sizing agent and a sulfuric acid band were added in the same manner as in Example 1 to change only the addition amount of the internally added talc and the basis weight. 54.2 g / m ² , thickness 62 μm, ash content 10%
The paper support of No. 3 was produced.

On the other hand, steamed oxidized starch (the same as in Example 1) was prepared in the same manner as in Example 1 and coated so that the coating amount on both sides was 1.0 g / m ² , and the sheet passing speed was 500 m.
/ Min, bottom nip pressure 180Kg / cm, total nip pressure 120
Supercalendering was performed under the condition of 0 kg / cm. Table 2 shows the results of the physical property test. Gloss strength is strong, but gloss is 1
As low as 3%, it is unsuitable for producing beautiful and well-printed printed matter, and also unsuitable as gravure printing paper.

[0047]

[Table 2]

The test methods and evaluation methods for glossiness and surface strength are as follows. Test method (1) Glossiness Murakami type gloss meter GH-26D type was used for measurement. The measurement is performed at an incident angle of 75 °. The sample is irradiated with light, and the larger the numerical value measured by receiving reflected light on the light receiver according to the gloss of the sample, the better the glossiness.

(2) RI Surface Strength A coated paper was printed under the following printing conditions by using an RI printability tester (RI-2 type, manufactured by Meisei Seisakusho Co., Ltd.), and fibers were fluffed on the surface of the printed matter and fibers were peeled off. Was evaluated.

Printing Conditions Type of Ink Polybden Ink Tack of Ink 22 Equivalent Blanket Nip Pressure 10 mm Printing Speed 30 m / min Surface strength was visually evaluated in the following three stages. ◯: Fiber peeling is 1 to 3 or less □: 3 or more fibers are peeled, but not on the entire surface Δ: Fiber peeling is generated on the entire surface or one of the peeled fibers Each one is big

(3) Missing Dod (Gravure Evaluation Method) The missing dod was printed on the coated surface under the following printing conditions using a Ministry of Finance Printing Bureau type gravure printing tester (manufactured by Kumagai Riki Kogyo Co., Ltd.), and the 20% floor The number of missing dots in the halftone dot number of 5,000 was evaluated in the adjustment part.

[0052]

INDUSTRIAL APPLICABILITY According to the present invention, a clear size coating solution is applied to a base paper containing mechanical pulp, and a glossing device is used to select and process it so that the offset multicolor printing has a good appearance. Printed matter can be obtained.

Claims (1)

[Claims] 1. A paper support having 50-80% by weight of all pulp components is mechanical pulp and / or deinked waste paper pulp, and ash content (JIS P-8128) is 5-25% by weight. The clear size coating layer has a thickness of at least one side of 0.
² to 1.5 g / m ^{2 is} applied, and the glossiness of the applied surface is 15 to 25%.