FI123481B - Process for producing printing paper and blend composition - Google Patents

Description

METHOD FOR PREPARING PAPER PAPER AND COMPOSITION COMPOSITION

FIELD OF THE INVENTION

The invention relates to a method for producing printing paper as defined in the preamble of claim 1 and to a mixture composition as defined in the preamble of claim 6 for surface sizing of printing paper.

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BACKGROUND OF THE INVENTION

Various methods of making various printing papers are known in the art. In addition, various papers are known in the art for use in printing, e.g., various ink-jet based printing.

With inkjet based printing techniques, it is important to ensure sufficient ink absorption in high-speed inkjet papers to obtain sufficient color prints. It is important that the inks of different colors do not mix. For uncoated papers, sufficient absorption can be guaranteed with a low level of hydrophobic sizing of the base paper, as disclosed, for example, in WO 25/2006067273.

It is known that an anionic water-based ink should be bound to paper in order to make the print tL waterproof. Water resistance is essential, for example, in bank statements and other similar printing products. It is known that water resistance can be

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£ shore by adding cationic polymers to the surface of the paper to the surface of the adhesive or coating. The most commonly used polymer is polyDADMAC. Many fixtures used in the wet end of a paper machine are suitable for this purpose. Patent application WO 2006067273 discloses a surface treatment of a printing paper with a cationic polymer in combination with a pulp sizing treatment of the paper. The optimum amount is suggested to be 2 g / m 2, whereby about half of the amount of surface adhesive should be replaced by 5 cationic polymers. The amount of cationic polymer described above raises the cost of producing the paper to be printed.

PURPOSE OF THE INVENTION

The object of the invention is to eliminate the above-mentioned drawbacks. It is a further object of the invention to provide a novel process and surface adhesive composition for producing printing paper. In particular, it is an object of the invention to provide a new way of improving the printability of printing paper.

SUMMARY OF THE INVENTION

The process and composition of the invention are characterized by what is set forth in the claims.

The invention is based on a process for producing printing paper, in which uncoated paper is formed. According to the invention, a surface adhesive mixture containing 25 starches and polyvinylpyrrolidone containing less than 5% crosslinker is provided on the uncoated paper to improve the printability of the paper. o cvj Wettability refers to print quality, water resistance, and / or color absorption rate and - i cd 30 speed. Print quality refers to the sharpness and / or smoothness of the print, cc

The invention is specifically based on improving the printability of an inkjet by means of a new surface adhesive composition in uncoated papers. [0035] In this context, "paper" refers to any fiber-based paper, board or fiber product or the like. The paper may have been formed from pulp, mechanical pulp, chemimechanical pulp and / or the like. The paper may be in the form of a sheet, web or sheet, or in any other suitable form. The paper may contain suitable fillers and additives.

In one embodiment of the invention, the process generally uses uncoated fine paper without mechanical pulp, e.g., WFU or 10 UWF. Alternatively, uncoated paper containing mechanical pulp, e.g. SC paper or newsprint may be used.

In one embodiment of the invention, high speed inkjet paper with good printability is produced.

In one embodiment of the invention, the adhesive composition is in the form of a solution, dispersion or paste. The mixture may be arranged or applied to the surface of the paper in any manner known per se in the art.

In one embodiment, the surface adhesive composition is applied to the surface of the formed paper web during web formation, e.g., during drying. In one embodiment, the mixture is applied to the surface of the formed web in a separate step after its formation.

In a method embodiment, a base paper web is formed in a manner known per se, which is cut to the correct width. The web is coated with a surface adhesive compound. If desired, the web is cut into sheets or sheets

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and the paper or articles cut from it are subjected to the desired printing in the desired manner.

V 30 In one application, printing can be done on a digital-

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Ί printing method, eg inkjet based jr technique.

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Further, the invention is based on a blend composition for use in the production of printing paper. According to the invention, the alloy composition contains starch and poly cm vinyl pyrrolidone and less than 5% crosslinker, and the alloy composition can be provided on the surface of uncoated paper as a surface sizing agent.

The cross-linker may be, for example, an epoxy-based, glyoxal-based or zirconium-based cross-linker.

In one embodiment of the invention, the blend composition comprises a cationic polymer. In one embodiment, the blend composition contains less than 15% cationic polymer.

In one embodiment of the invention, the blend composition 10 contains 45 to 99% starch.

In one embodiment of the invention, the blend composition contains from 1% to 50% polyvinylpyrrolidone. Polyvinylpyrrolidone may be in any form and may exist as a pure substance or mixture.

Significant advantages over the prior art are achieved by the method and surface adhesive composition of the invention.

The surface sizing composition of the present invention provides a printing paper having excellent print quality and improved printability properties. In addition, the surface sizing composition of the invention provides a shorter color absorption / settling rate during printing.

The invention provides an industrially applicable easy and fast way to produce printing paper. The process according to the invention is easy, simple and inexpensive to carry out in the production process. The process according to the invention is suitable for use in the production of various printing papers, especially those of the high-speed inkjet type.

Er in the manufacture of printing papers.

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? DETAILED DESCRIPTION OF THE INVENTION

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Example 1 In the experiments of this example, various surface sizing compositions for use in WFU paper for high speed inkjet printing were investigated. The experiments were performed on a laboratory scale.

The experiments investigated and tested the effect of PVP (polyvinylpyrrolidone) as a surface sizing agent in non-pigmented compositions for surface sizing of paper. The results obtained were compared with those obtained with the reference composition. The reference composition 10 was a predominantly starch-containing surface adhesive which did not contain PVP.

Lightweight, uncoated fine paper with a basis weight of about 82 g / m 2 and Cobb values of about 60 to about 15 5 g / m 2 was used as the base paper. The paper was glued on one side with an RK lab coat and a rod of about 3 g / m2. The compositions of the topcoat compositions are shown in Tables 1 and 2. The pH of the topcoat mixture was 7.5.

The surface-bonded papers were printed with two 20 inkjet printers; Epson Stylus C46 with Versamark Ink and Canon Pixma iP3000.

Printed papers were determined for printing ink absorption, line spreading and roughening, water resistance (K, M), water resistance to abrasion, and density. The visual properties of the printed papers were examined by three persons.

Waterfastness refers to c / d after irrigation / d prior to irrigation x ^ 100%. A higher value indicates better water resistance; The value of V 30 can be over 100%. When scrubbing with water (wet

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i-rub) refers to the darkness of the white area,

No after / black area darkness before rubbing.

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A lower value indicates better water resistance to rubbing x 100%; the value may be zero, o ^ 35 Table 1 shows the o cm substances used in the experiments. Table 2 shows the surface sizing compositions used in the various tests. The dry solids content of the compositions was about 12%. Table 3 shows the results determined from printed paper.

Table 1 5

Substance Substance Composition A cationic starch B aqueous solution of PVP (polyvinylpyrrolidone) C cationic polyalkylamide polymer_ D epoxy based crosslinker_ _E__glyoxal based crosslinker and_

In the experiments, PVP used a homopolymer of N-vinyl-2-pyrrolidone. It is soluble in water and in many organic solvents such as alcohols, amines, acids, chlorinated hydrocarbons and amides. In solution it has excellent wetting properties and good film forming ability. It is more hydrophilic than starch and a better OBA activator, but it is more difficult to cross-link.

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Table 2

Composition Ref 8 9 15 20 _A__100 70 50 90 70 _B___30 50 10 30 C \ j _C__15 15 15 15 15 O n 5 c \ j ______5_ τΐ [E_I 5 I 5 I 5 I 5 _

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£ 20 Table 3 c \ j O ------ O Score, Low Ref Ref 8 Ref 9 Ref 15 Ref 20 = C \ 1 Better Score _ 7

Absorption 1 1 1 1.5 2

Water resistance 1-2 1-2 2 0.5 0.5

Water resistance to rubbing 2 1 2 0.5 1 t

The cost of printing on 2-3 1 1 1.5 2, Griffin______

Density (C) 3222 1

Density (C) 3322 1.5

In experiments, it was found that the use of PVP in combination with starch in surface sizing provided good water resistance and water resistance to abrasion on printed paper without substantially reducing the density compared to other compositions. PVP was found to persist on the surface of the paper, i.e., it has a lower migration into the paper than starch. Therefore, PVP provided a faster ink absorption, lower ink dispersion and better water resistance. A fast ink absorption time is beneficial in reducing ink dispersion.

Experiments found that PVP in combination with starch significantly improves the water resistance of the print and the quality of the black and white print, such as the sharpness and smoothness of the print, compared to the reference alloy treated paper o (Ref).

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20 Summarizing the experiments it can be stated that "*" PVP together with starch

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an effective composition for surface sizing of printing paper.

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^ 25 Example 2 l '' - o ^ The experiments in this example investigated various surface sizing compositions for use in WFU paper for 8 high speed inkjet printing. Experiments were conducted on a pilot scale.

The experiments investigated and tested the effect of PVP (polyvinylpyrrolidone) as a surface sizing agent in 5 non-pigmented compositions for surface sizing of paper. The results obtained were compared with those obtained with the reference composition. The reference composition was predominantly a starch-containing surface adhesive which did not contain PVP.

The base paper of Example 1, which was similarly coated with a 2.5 g / m 2 surface adhesive, was used in the tests. The surface adhesive composition compositions are shown in Table 4. The compositions had a dry solids content of 12%.

15 The papers were printed with ink jet printers;

Epson Stylus C48 with Versamark Ink, Canon Pixma iP3000 and HP Deskjet 6540.

Table 4 20

Composition Ref 5 6 7 _8__11 _A__100 70 70 70 90 50 _B___30 30 30 10 50 SMA, Im- 5

press SC

740_______ C 15 15 15 15 15 15 C \ J ------- t —i D 5 5 5

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[E__ 5 __ | 5 | 5_

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In the experiments, it was observed that the Digat absorption time was reduced when using PVP in the adhesive composition cg compared to the results obtained with the reference adhesive mixture. In the experiments, the black color absorption time for o PVP (Compositions 5-8 and 11) was ≥ 100 to 200 ms and for starch alone (Ref) was above 300 ms.

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Water resistance was found to be good for all compositions, preferably above 100%. The water resistance to rubbing was also good for all compositions, preferably less than 12%.

The color density was also found to be at a good level when using PVP regardless of the printing device relative to the results obtained with the reference composition.

Example 3 This experiment investigated the printing of surface-glued papers with the compositions of Experiment 2 on digital high speed inkjet printing machines.

The water resistance of the printed paper, the water resistance to abrasion, the color run-off into the white area, the color density, the print uniformity and the printing were found to be good for all PVP-containing compositions relative to the reference composition.

Wa-terbleed refers to the darkness of the white area after watering / the black area before watering x 100%. A lower value indicates a better result. Ta-25 has a win rate of less than 10%; the value can be zero.

In addition, it was found in the experiments that the settling time of Digat ink was shorter when using a PVP-containing adhesive composition compared to the reference composition. The settling time with PVP-containing composition V 30 was generally less than 150 ms.

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The runnability and printability of ir paper containing i-PVP in the pt-sizing composition was found to be

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van good in weight tests.

In the printing experiments of Examples 2 and 3, the preferred aus35 composition for the surface sizing composition appeared to be ≤ 8 composition with 10 parts PVP and 90 parts starch.

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The results of the pilot tests (Example 2) and weight tests (Example 3) supported the results obtained on a laboratory scale. The PVP-containing adhesive composition provides excellent printing paper 5 with good printability and print quality.

The method according to the invention is suitable as a variety of applications for use in the production of a wide variety of printing papers.

The invention is not limited to the examples set forth above, but many modifications are possible within the scope of the inventive idea defined by the claims.

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Claims (9)

1. A process for making printing paper, in which an uncoated paper is formed, characterized in that a surface adhesive mixture containing starch and polyvinylpyrrolidone containing less than 5% cross-linking agent is provided on the surface of the uncoated paper. printability. 10 Process according to claim 1, characterized in that the surface adhesive mixture is in the form of a solution or a dispersion. Method according to claim 1 or 2, characterized in that the method is used mainly with uncoated fine paper which does not contain mechanical pulp. Method according to any one of claims 13, characterized in that the inkjet printability of the paper is improved. 20 Process according to any of claims 1 to 4, characterized in that high speed inkjet paper with good printability is produced. 6. A blend composition for use in the production of printing paper, characterized in that the blend composition contains starch and polyvinylpyrrolidone and under 5% crosslinking agent, and that the blend composition o can be provided as a surface adhesive on the surface of uncoated paper. Blend composition according to claim 6, characterized in that the blend contains cationic polymer. X Blend composition according to claim 6 or 7, characterized in that the blend 5 contains 1 - 50% polyvinylpyrrolidone. § 35 A blend composition according to any one of claims 6 to 8, characterized in that the blend contains 45 - 99% starch.