FI116574B - Print material and printing method - Google Patents

Description

116574

Printing Material and Printing Method

The invention relates to printing material consisting of surface-treated paper for use in the heatset web offset printing process. The invention also relates to a printing method in which surface-treated paper is printed by the heatset web offset method. The paper of the invention can also be used in the gravure printing process.

LWC papers with suitable surface properties are printed using the heatset web-10 offset method. This printing method transfers a subject to be printed from the actual printing plate through a special offset rubber roll (so-called offset blanket) to the paper fed in the form of a continuous web. The offset transfer of the printed subject to the paper is based on the transfer of color from a flat surface (rubber roll surface) onto which it is applied from a printing plate whose oil-based ink has been transferred to the oleophilic areas after application of wetting water. The printing plate can also operate by the dry offset method without wetting water. Once the subject has transferred to the paper, the ink is dried by heat to evaporate the solvent from the ink. At the same time, the paper shark: '-20 brings water from the offset rubber roller and much of the paper: / · j's own moisture.

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Certain quality properties are required for printing paper for the heatset offset method. Papers developed for this printing method. * •• 25 ribs having the desired properties for the printing method are known among others. European Patent 5,392,771 and GB-2047568. These are characterized by the use of CaCO 3 pigment to increase porosity and optimization of the porosity of the paper. The printing process itself has been described e.g. in German Application Publication DE! '* .30 3207463.

In the prior art, printing papers have been developed based on the fact that the paper must be somewhat porous to absorb transferable wetting water and to remove moisture evaporating from the paper during hot air drying.

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The object of the invention is to provide a completely new type of printing material having a surface suitable for the heatset web offset printing process. To accomplish this purpose, the printing material of the invention is essentially characterized by what is set forth in the characterizing part of claim 1 of the appended claims.

It is also an object of the invention to provide a novel heatset web offset printing method in which the printing material is fed continuously through one or more printing units, in which the ink 10 is transferred to the substrate, after which the web is dried.

The print material is dense, oleophilic paper. By this definition is meant that the oil displaces water on the surface of the paper. These properties have been achieved by suitable surface treatment of the base paper, in particular by coating and subsequent paper finishing. To avoid problems with color transfer and drying, the printing material differs from current porous and water absorbent paper used in heatset web offset printing. The printing material ensures that the ink dries as a surface: -20 phenomenon, whereby the moisture of the paper itself is not evaporated during drying, i.e. \ * ·; the final moisture content of the paper remains high. In addition, these surface properties: · minimize the amount of wetting water transferred to the paper and the need for color ·: ··: (the oleophilic dense surface repels wetting water and prevents its transfer to the paper structure).

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The printing process using the printing material according to the invention can be optimized by using a printing ink having suitable properties and wetting water. The ink is of an easy-drying nature (low solvent content and / or low solvent boiling point and low solvent retention in ink binder). Dense paper allows for easy drying and settling of ink (no problems with ink settling). The wetting water is preferably non-alcoholic.

The printing material according to the invention satisfies the following conditions: 3 116574 1) The tS value of the EMCO water absorption is greater than 0.5 seconds. This property describes the time at which water absorption from paper changes from capillary absorption to fiber absorption.

2) The Tack build-up value obtained by ISIT measurement on paper is greater than 5,100 seconds for ink having a Tmax of 270-300 s achieved in Tack-O-Scope Density Measurement. with the well-known Sun-Challenge ink. The result of the ISIT measurement describes the ink settling rate, which correlates with the porosity of the paper surface. ISIT measures the porosity of a paper surface in terms of ink absorption.

Preferably, the paper is a coated paper containing a sheet-like pigment as a coating pigment. By selecting the coating composition (coating paste) for the pigment and the latex binder and the quality of the latex binder 15, the surface properties can be further adjusted. The shape factor of the sheet-like pigment, i.e. the ratio of the diameter of the pigment to the thickness, is greater than 2 and preferably greater than 4. The shape factor is preferably still greater than the above values to obtain a dense surface. Therefore, talc is preferably used as the pigment for the coating, either alone or in admixture with kaolin. The flatness of the talc, i.e.: * ·. · A large shape factor, preferably greater than 25, contributes to the surface tightness. Similarly, the softer the latex used (low Tg) and the higher the amount of latex relative to the pigment, the thicker. . the latter is the surface. Also, increasing the cross-linking of latex increases the seal -. '.. 25 cores.

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The invention will now be described in more detail with reference to some examples:: '': which are not limiting of the invention.

> I t 30 Papers * 'In the printing material of the invention, the base paper was; Typical LWC base paper, 12% ash content and fiber composition:. j 40% chemical pulp and 60% mechanical pulp (TMP).

The basis weight was about 36 g / m 2 and the density was about 660 kg / m 3.

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The paper was coated with coating compositions having the following components

Talc (C10X0 or C15) pigment

Kaolin (Supragloss95) pigment

Styrene Butadiene Latex (Rhodopas 388) Latex Binder Starch (Raisamyl 302) Binder

Surface Chemistry Adjustment of Styrene Maleic Anhydride (Raiprint D100 or D200)

Calcium stearate (Raisacoat 50) Calendering aid

Optiblank N F Optical Brightener

Glyoxal Cross-linking The coating paste had a dry solids content of 58% and a pH of 7.5. Latex Rhodopas 288 had a Tg value of 0 ° C, i.e., a Tg value (glass transition temperature) lower than normal offset printing paper latex. For example, the use of latex having a Tg of less than 5 ° C can improve the sealing of the coating.

. '• Λ0 The following table shows the compositions (in parts by weight) of the different coating pastes.

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Table 1 • · I I | titi. Coating pastes no. 1_2_3__4_5_6_8_ C10XQ__70_70_____40_70_70_: ·· *: C15 _____ 7Ό_JOO ____

Supragloss__30 30 30 _60 30 30

Rhodope SB 388 _10_J5_JO_JO_JO_JO_JO_ \ .J Raisamyl 302__2_3_3_ 3_3_3 3_ D200___3_3_3 3_3__! ···. D100 * __ J________, Λ RC Cas 50__0.5 0.5 0.5 0.5 0.5 0.5 0.5 \ .V Optiblanc N F__0.2 0.2 0.2 0.2 0.2 0, 2 0.2

Glyoxal | θ, 2 | θ, 2 10.2 [0.2 | o, 2 [0.2 | θ, 2 * D100 was cooked together with starch

The paper was coated with a blade coating (Opticoat-Jet). The upper side (coarser) of the paper having a basis weight of 36 g / m2 was first coated. The coating application target was 12+ 12 g / m 2. The final humidity target was 5.3% before calendering.

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After coating, the web was dried in an infrared and fluidized bed dryer.

The coated paper was rolled into rolls. Rolls for super-calendering with the top of the paper facing the first die roll. The conditions for supercalendering-10 were as follows:

upper: 120 ° C

middle: 110 ° C

area: 90 ° C

Payload: 320 kN / m

Speed: 500 m / min

Number of nipples: 9 pcs

The measured properties of the finished bilaterally coated papers are shown in Table 2 below. The numbers refer to the coating paste. : d to 5 digits.

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6116574

Table 2. Characteristics of Finished Papers _____ POST 1 (kp2) 5 (kp8) 6 (pcs 0) 3 (kp12) 8 (kp18) 4 (kp22)

Physical features________

Weight basis_g / m2 59.8 61.7 61.7 62.7 62.7 63.7 TP-coated g / m2 50.1 49.7 48.6 50.1 49.9 51 basis weight ________ Coating_g / m2 9.7__12 , 0__13J__12,6__12,8 12.7

Thickness PaperLab_pm 48_4 / 9__49__48_4β__48_

Density_kg / m3 1239 1262 1265 1298 1302 1319

Bulk_dm3 / kg 0.81 0.79 0.78 0.77 0.77 0.76

Surface Properties_________ PPS 10 VP_pm 0.96 1.05 1.04 1.07 0.93 1.10 PPS 10 VP_pm 0.99 1.01 0.91 0.91 0.73 1.10

Kiilto YP _% _ 63.0 67.5 63.3 59.4 65.2 49.1

Kiilto VP _% _ 58.6 67.2 64.5 59.3 65.0 48.6

Optical Properties________

Lightness VP% 74.5 73.3 73.4 71.7 73.6 72.9

Luminance VP% 78.0 77.6 77.2 76.2 77.1 76.4

Opacity VP _% _ 91.3 91.0 91.0 90.2 91.5 89.6

Hi, wavelength VP nm 573.1 573.6 573.1 573.7 573.2 572.6; '·· Stimulus purity VP _% _ 32_32_32_42_3.4 3,4_ • Porosity and Absorption • ·, i.e. Properties • ------— ~ -......

"VP \ Vibration Absorption VP__ 27.3 17.4 18.4 18.1 20.1 27.3 K&N Vibration Absorption VP__2J__1.3__1 ^ 3__1 ^ 5_1,5 3,4_ *****

Printability Properties__________ IGT Surface Strength VP_m / s 0.53 0.60 0.66 0.65 0.65 0.58

IGT surface strength VP

driving / comb direction m / s 0.53 / 0.48 0.63 / 0.58 0.75 / 0.58 0.78 / 0.53 0.78 / 053 0.68 / 0.48 * · ^ —- »* ^ 1. ........- - * - * - * - • * * * * * f «i * ·! 1 t t t 1 * * t I I t »i i t

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Even the low value of K&N color absorption (less than 4% in all cases, ranging from 1 to 4%) indicates dense paper.

5 The following known heatset web offset papers were used for comparison: SCO UPM Max 56 gsm LWCO UPM Cote 60 gsm UPM Ultra 70 gsm 10 UPM Ultra M 70 gsm (matte) MWC UPM Star 100 gsm WFC UPM Art 100 gsm

In the following, the properties of the paper, as measured by a different method, are discussed separately below.

Methods ISIT tack build-up determination method 20

The papers were subjected to an ink tack • y.j build-up test (ISIT, KCL Printing Technology). Test;: · The description is as follows.

»· ....: 25 The value of the Tack build-up, in seconds, is the time it takes for the substrate to be applied, ···. maximum ink develops on the ink. The test gives a graph of the sticky force as a function of time, and the tack build-up value (s) is the time between the start and the maximum point on the curve. In practice, the sticky force is determined by measuring the release force of the contact disc ...: 30 from the ink film on top of the paper. Using · * · .. the same color properties but different papers can be used. ···. This method also tests the surface properties of different papers.

The higher the value for the same ink, the denser is: · 'the surface of the paper.

:. '.: 35 Determination of tS value for EMCO Water Absorption 8 116574

The papers were subjected to a water absorption test in which the obtained tS value represents the time at which the water absorption of the paper changes from capillary absorption to fiber absorption. The value is obtained with a dynamic penetration measuring device DPM 27 ('' emco penetration measuring device ''), manufactured by emco 5 Elektronische Mess- und Steuerungstechnik GmbH, Leipzig.

The method is based on the use of ultrasound (frequency 2 MHz) to measure the penetration of liquid into wide surface materials (such as paper) and is based on the change in ultrasonic permeability as water penetrates the paper and the paper wetted at different stages.

10 The test paper is immersed vertically in water between the ultrasonic transmitter and the receiver. Penetration dynamics can be seen in the permeability versus time curve. The tS value is the time from the curve at which the transmission drops steepest from the start. Known uncoated papers have a low tS value, so tS-15 values can be excluded from the invention, although they (e.g. SCO paper) may have a slow capillary absorption due to their large pore size and consequently a relatively high tack build-up - value.

20 K&N Color Absorption: \ j The papers were subjected to a K&N color absorption test. The method is described below.

. ,,. 25 Paper Color Absorption, K&N Color • · *

Principle [t '] Test paper is applied to the test paper for a specified period of time. The darkness of the section left at ... $ 0 indicates the absorbency of the paper. The reflectance of the site is measured.

.Λ General I · t: ... 35 A test coat is applied to the paper sample to be examined. The unabsorbed dye is removed and the reflectance of the dyed spot 9 116574 is measured

Elrepho color meter. The paper is measured separately for the upper and lower color absorption, two test / side. The test color is applied to the side to be examined.

K&N Color 5 Coated paper grades use K&N test ink (color absorption time 2 minutes).

- Make 4 test-10 test strips of approximately 8 x 25 cm. The longer side is the machine direction of the paper.

The test strips are placed on a glass plate with 2 test strips face up and the other 2 strips face down.

The test strip is stained approximately 5 x 8 cm and the remainder is left clean. When applying the color, it is advisable to use 15 protective papers on the clean part.

The K&N test paint is thoroughly mixed in its jar with a narrow spatula and then applied to the tip of the spatula with a layer about 1 cm wide. From this, the color is applied to one test strip and the stopwatch is activated.

20 - Allow dye to absorb for 2 minutes, then remove excess: * ·· dye with a spatula and wipe the remaining non-absorbent dye with a lint-free cloth. Continue wiping until • no more lightening of the color is detected, 5-6 times.

- There must be so much color that it doesn't have enough time ... 25 to get absorbed in the paper.

..... - Suspend test strips and measure after 2 hours. The upcoming measurement time is recorded.

|: Initial color meter setting * '. J.'30 • * · .. 1. Power is on.

. ··. 2. The lamps are turned on for about 5 minutes before the measurement begins.

: 3. Check that the gray filter is on: the: ..§5 mark on the meter cover is visible.

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Measuring the Reflection Number 1. Perform a meter reset.

The filter selector is in position 12.

5 - Turn the reset potentiometer to adjust the pointer to zero. The sensitizer is then depressed and the zero point adjusted again.

2. Use the filter selector to turn filter # 10 on.

10 - The internal standard is set aside.

3. Adjust the meter to 100 for the clean spot on the test strip.

Place a sheet of test paper on top of a colored test strip on top of the washer. Sheet stack 15 and test strip always in the same direction.

Place the clean spot on the test strip at the measuring opening and set the measurement drum to 100.

The meter is first reset by turning only the gray wedge and then again using the sensitizer.

20: * ·· 4. Measure the reflectance of the dyed spot.

- Move the stained spot on the test strip to the measuring hole.

·: · - The pointer is first reset to zero only by the measuring drum; : by turning and then using the sensitizer again.

.... 25. ···. The reflection number is directly measured by the measuring drum. Read the result to the nearest 0,1 unit. For each test strip, a reflectance measurement is performed as above. One measurement is made on the test strip.

Calculation of results R & D value,% = 100.0% - measured reflectance,%.

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Gurley Hill air permeability

The Gurley Hill value was determined for papers according to T536 om-88.

5 Inks 1. Sun Challenge This known color can best be characterized by the Tmax of 286 sec used in the 10 Tack-O-Scope Density Measurement known in the ink industry for determining the paper's sealing properties.

2. SICPA Mediatech Ultra Fast This color is particularly suitable for use in the heatset web offset printing process of the invention. It has 15 drying qualities and has a shorter Tmax of less than 200s. The color used in ISIT tack build-ups was between 100s and 150s.

The Tack-O-Scope measurement conditions for determining the ink properties were as follows: 0.4 g color, 30 s stabilization time at 100 20 m / min, running speed 200 m / min, and temperature 25 degrees (room temperature).

;: · Results .... The following tS values were obtained for 25 EMCO water absorption:

Papers according to the invention:. Pasta3 (kp12) 16.4 s *. / Pasta5 (kp8) 2.5 s •; · 30 Pasta 6 (pieces 0) 3.5 s

Known papers: UPM Cote 60 gsm (LWCO) 2.7 s UPM Max 56 gsm (SCO) 154 ms UPM Star 100 gsm (MWC) 7.4 s: ··· 35 UPM Ultra 70 gsm (LWCO) 1.7 s UPM Ultra M 70 gsm (LWCO) 1.5 s UPM Art 100 gsm (WFC) 6.4 s 12 116574 The following conditions were used in the ISIT tack build-up assay: 5 Suggested color amount: 100 mm3

Offset Color: 1.4 g / m2 Sun Challenge 1.5 g / m2 Sicpa Mediatech Ultra Fast Color Roll Time: 5s Roller + 5s Weight Disc Color Rotation Speed 0.7 m / s 10 One Print Per Color Spread 15 kN / m compression

Printing disc: 20 mm, rubber surface

Contact Disc Contact Time 0.5 s 15 Figure 1 graphically illustrates ISIT tack build-up values for three known papers and the inventive paper (paste 3, kp 12) when using Sun Challenge inks. The value of the paper according to the invention is more than 400 s, while it is well below 50 seconds on other papers.

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Figure 2 graphically illustrates ISIT tack build-up values for two known papers and the inventive papers (pastes 5 and 6, kp;: · 8 and 10) using Sun Challenge inks. Values for papers in accordance with the invention ·: ··· are more than 300 s, while for other papers it is clearly… 25 in less than 50 seconds.

Figure 3 is a graph showing ISIT tack build-up values for three hours. and paper according to the invention (paste 3, page 12) | using SICPA Mediatech Ultra Fast Inks. The value of the paper according to the invention *: * 30 is more than 200 s, while it is clearly less than 10 seconds on other papers.

Figure 4 graphically illustrates ISIT tack build-up values for two known papers and the inventive papers (pastes 5 and 6, kp '••• 35 8 and 10) using SICPA Mediatech Ultra Fast inks. Values for papers according to the invention are greater than 100 s, whereas for other papers they are well below 50 s.

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Figure 5 graphically shows the ISIT tack build-up values for one known paper using Sun Challenge inks and SICPA Mediatech Ultra Fast inks. Values for paper are well below 10 5 seconds.

From the results, the known, uncoated super-calendered paper UPM Max 56 gsm (SCO) has an ISIT Tack build-up of more than 100s because of its slow capillary absorption due to its high reflux rate, but its EMCO water absorption tS is only 154 ms. EMCO Water Absorption can be used to distinguish between uncoated supercalendered papers and coated dense-coated papers.

Figure 6 is a graphical representation of K&N color absorption and Gurley-Hill for four papers and known papers according to the invention.

Printing Method 20 The following is an example of a heatset web offset printing concept for which a printing material according to the invention is intended:

·; · Printing machine: Albert Frankenthal A101-S

Printing Speed: 6.2 m / s,., 25 Ink: SICPA Mediatech Ultra Fast

Humidifying Water 3% Humidifying Water Additive Sicpa Soi Alcofree Remaining Tap Water

Drying: End of line temperature 95 ° C

Length of dryer: 8 meters

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“... The printed matter can also be printed under other conditions and use. · · ·. other raw materials for the printing process.

The following is another printing paper according to the invention which: ... 35 is suitable not only for the heatset web offset but also for the gravure printing process. The papermaking process was the same as above, but the composition of the coating paste used was as follows: 14 116574

Talc (C10X0) 60 parts

Kaolin (Supragloss 95) 40 parts CMC (FinnFix 10) 0.8 parts 5 SB latex (Rhodopas PE1416) 10.5 parts

Styrene Maleic Acid (Raiprint D200) 1 part

Calcium Stearate (Raisacoat 50) 0.5 parts Optical Brightener (Optiblanc NF) 0.2 parts 10 The dry matter of the coating paste was 59% and pH 8.0. The coating application target was 10 + 10 g / m2. The final moisture target before the calender was 5.5%. The base paper was LWC base paper, chemical pulp 40%, mechanical pulp 60%, basis weight 43 and 41 g / m 2. The smoother side (top-15 side) was first coated. Calendering temperatures (upper / middle / lower) were 100 ° C / 90 ° C / 80 ° C.

The paper meets the above specifications for heatset web offset printing paper, but the selection of coating paste also takes into account the smoothness and compression properties required for gravure printing paper. As a result, the starch has been left out of the pasta paste and the latex is even softer (Tg - 20 ° C).

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Claims (11)

116574 1. an EMCO water absorption tS value greater than 0.5 seconds; and 1. an EMCO water absorption tS value greater than 0.5 seconds; and 1. A printing material which is hand-woven paper with a surface texture suitable for use as an oleophilic paper that meets the following conditions: 2. The Tack build-up value obtained by ISIT measurement is greater than 100 s with Sun-5 Challenge Ink. Printing material according to Claim 1, characterized in that the Tack build-up value is greater than 200 s, preferably more than 250 s, with said ink. 2. The Tack build-up value obtained from the ISIT measurement is greater than 100 s with a printing ink having a Tmax 10 stability of 270-300 s achieved with the Tack-O-Scope. Printing material according to claim 1 or 2, characterized in that it is coated paper. Printing material according to Claim 3, characterized in that the coating comprises a pigment. A printing material according to claim 4, characterized in that the pigment of the coating is a plate-like pigment. *: · 25 The printing material according to claim 5, characterized in that the pigment shape factor (ratio of pigment diameter to thickness) is greater than 2, preferably greater than 4. I ·. . 7. A printing material according to claim 6, characterized in that the pigment is talc either alone or in admixture with kaolin. »» * Printing material according to one of the preceding claims, characterized in that it is a heatset web offset printing material. i i « 9. A Heatset web-offset printing process wherein a paper of suitable surface finish is passed through a continuous web or one or more of 116574 weight units, characterized in that the paper is an oleophilic surface that meets the following conditions: Method according to claim 9, characterized in that the final temperature of the paper web after the printing press dryer is below 115 ° C, preferably below 100 ° C. 10 11. A method according to claim 9 or 10, characterized in that the ink is an easily drying ink having a stability Tmax of less than 200 s in Tack-O-Scope. · · <»> 116574