Lithographic band for electrochemical graining, as well as method for its manufacture

FIELD: metallurgy.

SUBSTANCE: band for electrochemical graining consists of a rolled aluminium alloy. Band surface has a topography, the maximum peak height Rp or Sp of which is not more than 1.4 mcm, preferably not more than 1.2 mcm, in particular not more than 1.0 mcm. Besides, the invention relates to a manufacturing method of a lithographic band, as per which a lithographic band consisting of an aluminium alloy is subject to cold rolling and as per which, after the last run of the cold rolling, it is subject to degreasing treatment with an etching stage with a water etching medium, which contains at least 1.5-3 wt % of the mixture of 5-40% sodium tripolyphosphate, 3-10 wt % of sodium gluconate, 3-8 wt % non-ionic and anionic SAS, and when necessary, 0.5-70% of soda. Concentration of sodium hydroxide in the water etching medium is 0.1-5 wt %, and surface erosion as a result of degreasing treatment with simultaneous etching stage is at least 0.25 g/m2.

EFFECT: improvement of properties.

16 cl, 8 dwg, 3 tbl

 

The invention relates to lithographic tape for an electrochemical granulation consisting of rolled aluminum alloy. In addition, the invention relates also to a method of manufacturing lithographic tapes, which consists of aluminum alloy lithographic tape is subjected to cold rolling and in which lithographic tape after the last pass of the cold rolling is subjected to a degreasing treatment with a simultaneous stage etching aqueous pickling environment and water etching medium contains at least 1.5 to 3 wt.% a mixture of 5-40% of sodium tripolyphosphate, 3-10 wt.% gluconate sodium, 3-8 wt.% non-ionic and anionic surface-active agents (surfactants), and optionally 0.5 to 70 wt.% soda, and the concentration of sodium hydroxide in aqueous pickling environment is 0.1-5 wt.%. Finally, the invention relates to a method of manufacturing the basics of the printing form, and it provides the advantage of the application.

The nature of the surface of the lithographic tapes, i.e., aluminum tapes for the manufacture of lithographic basics of printing forms, very high requirements. Lithographic tape is customarily stage electrochemical granulation, the purpose of which shall be continuous, the grain size and structureless. Granulated structure is important for the application of photosensitive with the HH on made from lithographic tapes basics of printing forms. Therefore, in order to create a uniform granulated surface, necessary especially smooth surface of a lithographic strips. The topography of the surface of the lithographic tape is essentially an impression of the topography of the rolls during the last pass of the cold rolling. Elevations and depressions on the surface of the rolls are a consequence of the grooves and protrusions respectively on the surface of the lithographic tapes, which on further stages of the manufacturing bases of printed forms may be partially preserved. The quality of the surface of the lithographic printing plates depends, therefore, on the quality of the surface of the rolls, and, consequently, on the one hand, from grinding technologies while processing the surface of the rolls, and, on the other hand, from the current wear of the rolls.

Measure to determine the quality of the surface of the lithographic tape is the average roughness Raaccording to DIN EN ISO 4287, DIN EN ISO 4288. When using modern manufacturing methods lithographic tapes in the last pass of the cold rolling already created a surface with an average roughness Raapproximately from 0.15 μm to 0.25 μm. These roughness values are valid for many applications.

In recent years, however, a growing demand for printed forms with very shallow structures granulation and/or relative activities is but a thin photosensitive coating. They are used, for example, in the increasingly widespread CtP (Computer to Plate "computer - printed form") technology, in which the printing plate can be exposed directly digitally through a computer. In addition, decreases as the thickness of the applied coatings and increases their complexity. When using currently available in the basic printing forms in these technologies often print defects. Flat topography lithographic sheet after rolling is therefore becoming an increasingly important quality criterion for lithographic tapes.

Attempts were made to optimize the grinding rolls to get less pronounced patterns rolls. Grinding technologies, however, is already optimized so that to further improve the quality of the way it is now very difficult. In addition, the surface quality after grinding rolls as a result of wear and tear when rolling decreases again, so is needed frequent re-grinding rolls. And finally, a very smooth surface of the rolls may have on the surface of a lithographic tape only minor friction effect, it may be slippage between the roller and lithographic tape and as a consequence, the violation of the rolling process or damage l tographically tape.

From EP 1172228 A2, EP 0778158 and EP 1232878 A2 known the basics of printing plates for lithographic printing.

When using other well-known from the prior art WO 2006/122852 A1 and WO 2007/141300 A1 ways lithographic sheet after rolling is subjected to etching to remove the interference which the oxide Islands on the surface of the tape and, thus, to improve subsequent electrochemical graining. Although the quality of the surface of the fundamentals of printed forms in this way, in principle, and improving, the problem of the above-mentioned print defects in the future still remains.

Proceeding from this prior art in the basis of the present invention have the task to offer lithographic tape and method of its manufacture, on the basis of which you can eliminate or at least weaken the manifestation known from the prior art disadvantages.

This task is relevant to the generic concept of lithographic sheet in accordance with the invention is solved due to the fact that the belt surface has a topography, the maximum height of peaks Rpand/or Spwhich is not more than 1.4 μm, preferably not more than 1.2 μm, particularly preferably not more than 1.0 μm.

Under the surface topography of the ribbon understand its deviation from an ideal plane. It can be described by the function Z (x,y), which every point of the surface ribbon (x,y) before anyway local deviation from the average surface height. The average value of the function Z (x,y), i.e. the average position of the surface, installed under this to 0, as follows from the following formula:

Z(x,y)=1FZ(x,y)dxdy=0(1)

F - value of the integration area. Local elevation correspond to the positive indicators, and local depressions correspond to negative indicators that are measured in the Z (x,y).

The properties of this topography can be expressed in various ways. The usual rate is the average roughness Raor mean square roughness Rqaccording to DIN EN ISO 4287, DIN EN ISO 4288. These indicators are defined by the following equations:

Ra=1L|Z(x)|dx

Rq=1LZ (x)2dx(2)

Z(x) is the surface profile, i.e., one-dimensional section of the function Z(x,y), L is the length of the integration interval. To determine the quality of the surface plane in practice in different areas of the surface are measured one-dimensional profiles Z(x) by linear scanning, and define the appropriate indicators Raand Rq.

Values of Saand Sqdetermined on the basis of the results of the two-dimensional measurement of the surface, so the topography Z(x,y). Calculation of values of Saand Sqmanufactured using the following equation, where A is the magnitude of the integration surface:

Sa=1A|Z(x,y)|dxdy

Sq=1AZ(x,y)2dxdy(3)

In the framework of the present invention it was found that known in the prior art print defects are often caused by individual especially high ledges of the rolls, in which the production process can partially imprinted on the basics of printing forms. In the coating process on the basis of printed forms in the region of these roll projections can then be gaps in the photosensitive layer, when using printed forms lead to print defects. High roller ledges for printing forms a flat structure granulation and/or relatively thin photosensitive coating proved to be particularly problematic.

The presence of some high ridges on the rollers used is still an indicator of Raor Sato characterize the surface of the lithographic tape recorded, however, only to an insufficient extent. On the contrary, the probability of a high roller ledges and, thereby, occurrence of the above-mentioned printing defects may be reduced due to the fact that the lithographic tape or the method of its manufacture is optimized with regard to another is still not taken into account the measure of roughness. By limiting the maximum peak height Rpand/or Spto not more than 1.4 μm, preferably not more than 1.2 μm, particularly not more than 1.0 μm, it is possible to provide for the use of litor the specific tape, which meet the current high requirements to the surface quality, for example, when using CtP technology.

To determine the maximum peak height Rplithographic tapes in practice in three places lithographic tape across the direction of rolling to measure profiles Z(x) each time through, for example, 4.8 mm, to determine the value of Rp. For each of these profiles has the power

Rp=max(Z(x)) (4)

moreover, the function max (Z) represents the maximum value of Z(x). Spdetermined by the results of the measurement surface using the equation

Sp=max(Z(x,y)) (5)

moreover, the function max Z(x,y) represents the maximum value of Z(x,y). Subject to the measurement surface can be, for example, square and have a side length of 800 μm.

It is preferable to determine the maximum peak height Rpevery time is measured profile Z(x) in the middle and on the sides of the lithographic tape.

Needless to say that the measurement of the profile Z(x) or topography Z(x,y) is provided only in the areas of lithographic tapes, of which in the following shall be made the basis of printed forms. Damaged areas or areas with defects in rolling, for example, was not provided.

In the first embodiment, the lithographic tape surface is the efficiency of the tape has a topography, reduced height Rpkpeaks and/or Spkwhich is not more than 0.4 μm, preferably less than 0.37 μm. It was found that the surface quality of the tape in the absence of print defects can be enhanced even more by the additional control of its reduced height Rpkpeaks and/or Spk.

Reduced the height of peaks Rpkdetermined according to DIN EN ISO 13 565. Reduced the height of the peaks of Spkalso determined according to DIN EN ISO 13 565 by measuring surface. In practice, the profile Z(x) or topography Z(x,y) can be defined in the same way as described above for Rpor Sp.

In yet another embodiment, the thickness of the lithographic sheet is from 0.5 mm to 0.1 mm, it Turned out that conventional lithographic sheet of small thickness can have a high roller ledges. Therefore, the surface quality thinner lithographic tapes by limiting the maximum height of peaks Rpand/or Spor the reduced height of the peaks Rpkand/or Spkcan be improved particularly.

Good material properties lithographic tapes are achieved in another embodiment, the lithographic tapes due to the fact that the lithographic tape consists of alloy AA1050, AA1100, AA3103 or AlMg0.5.

In yet another prefer enom embodiment, the alloy lithographic tape has the following composition (in wt.%):

0,3%≤Fe≤1,0%,

0,05%≤Mg≤0,6%,

0,05%≤Si≤0,25%,

Mn≤0,05%,

Cu≤0,04%,

the rest is Al and impurities, individually, a maximum of 0.5%, amounting to a maximum of 0.15%.

Thanks lithographic tape, taking into account the scope of its application, can be especially improved in respect to its strength and heat resistance.

High resistance to bending symmetric cycle while simultaneously very good heat resistance lithographic tapes in one embodiment, can be achieved due to the fact that the dopant in the alloy lithographic tapes have the following shares (in wt.%):

0,3%≤Fe≤0,4%,

0,2%≤Mg≤0,6%,

0,05%≤Si≤0,25%,

Mn≤0,05%,

Cu≤0,04%.

In yet another embodiment, the doped impurity in the alloy lithographic tapes have the following shares (in wt.%):

0,3%≤Fe≤0,4%,

0,1%≤Mg≤0,3%,

0,05%≤Si≤0,25%,

Mn≤0,05%,

Cu≤0,04%.

This way can improve the characteristics of the lithographic sheet in respect of granulation and heat resistance.

According to another variant implementation of the maximum concentration of impurities in the alloy lithographic sheet as follows (in wt.%):

Cr≤0,01%,

Zn≤0,02%,

Ti≤0,04%,

B≤50 million-1(ppm).

Titanium may be added specifically to a concentration of 0.04 wt.% to reduce the grain size.

The above task in another idea of the invention according to stoysin generic concept of a method of manufacturing a lithographic tape in accordance with the invention is solved by that surface erosion by a degreasing treatment with a simultaneous stage etching is at least 0.25 g/m2preferably at least 0.4 g/m2.

It is established that preventing high roller protrusions on the surface of the lithographic tape after the last pass of the cold rolling can be reduced by special degreasing treatment with a simultaneous stage of etching. Etching treatment to remove the oxide Islands known, targeted deletion of the roll of tabs so far been unknown. By the use of appropriate pickling or degreasing environment and technological options now may instead or additionally to create the topology of the surface of the lithographic tapes, which in comparison with known still lithographic tapes has significantly less exposure to print defects due to the high roller ledges. As degreasing treatment with the stage of etching the surface of the lithographic tape is a very critical process, the method requires a very precise selection of process parameters. In particular, the composition of the etching medium, and the temperature of the etching and the etching duration must be set such that, on the surface lithographica the ribbon during a degreasing treatment with the stage of the etching surface erosion has been reached, at least 0.25 g/m2. In this way may give the surface of the lithographic sheet, the maximum height of Rppeaks and/or Spwhich is not more than 1.4 μm, preferably not more than 1.2 μm, especially preferably not more than 1.0 μm.

Under surface erosion refers to the remote during a degreasing treatment with stage etching weight lithographic tapes per square. To determine surface erosion lithographic tape is weighed before and after a degreasing treatment with the stage of etching. Defined in this way, the weight loss divided by the size of the treated area represents the surface erosion. When bilateral degreasing treatment with stage etching lithographic tape is necessary, therefore, to summarize the area of the front side and rear side.

Brings the greatest benefit was installed surface erosion in the range of between 0.25 g/m2and 0.6 g/m2, preferably in the range between 0.4 g/m2and 0.6 g/m2. Such erosion, on the one hand, large enough to reduce the high ledges, on the other hand, is not greatly reduced the thickness of the lithographic tape. In principle it would be desirable to avoid as less erosion to the loss of material during degreasing of the development to the stage of etching was as little as possible.

The topography of the surface of the lithographic tape in a preferred embodiment, the method can be improved due to the fact that the concentration of sodium hydroxide in aqueous pickling environment is 2-3,5 wt.%, and, if necessary, a degreasing treatment with stage etching is performed at a temperature of 70-85°C for 1-3,5 sec. At these concentrations, temperatures, and duration of treatment can be achieved particularly reliable conforming to the invention topography.

Further improvement is achieved due to the fact that the concentration of sodium hydroxide in aqueous pickling environment is 2.6-3.5 wt.% and/or the temperature of the etching is 76-84°C. this makes possible a shorter duration of treatment when still even removing the high roller ledges. Further improvements in speed degreasing treatment with stage etching lithographic tape can be achieved due to the fact that the duration of the etching is 1-2 with, preferably 1,1-1,9 C.

According to another variant of the method of lithographic tape in the last pass of the cold rolling rolled to a final thickness of from 0.5 mm to 0.1 mm, preferably Under these specified values of the thickness of the rolling are particularly high roller ledges, which means the degreasing treatment with the stage of etching can be reduced significantly.

As the aluminum alloy in accordance with another embodiment uses AA1050, AA1100, AA3103 or AlMg0.5. These aluminum alloys to ensure properties lithographic tapes proved to be particularly preferred.

In yet another embodiment of the method, the aluminum alloy has the following composition:

0,3%≤Fe≤1,0%,

0,1%≤Mg≤0,6%,

0,05%≤Si≤0,25%,

Mn≤0,05%,

Cu≤0,04%,

the rest is Al and inevitable impurities, individually, a maximum of 0.05%, amounting to a maximum of 0.15%.

Action degreasing treatment with the stage of etching depends on the alloy lithographic tape. Found that when using the alloy of this composition with optimal technological parameters for degreasing treatment with the stage of etching can be achieved very good results in relation to surface topography and good material properties lithographic tapes.

In other embodiments, the method of doping impurities in the aluminum alloy is contained in the following amounts (in wt.%):

0,3%≤Fe≤0,4%,

0,1%≤Mg≤0,3%,

0,05%≤Si≤0,25%,

Mn≤0,05%,

Cu≤0,04%.

Inevitable impurities alloy lithographic tape according to another variant implementation have the following maximum allowable concentration:

Cr≤0,01%,

Zn≤0,02%,

Ti≤0,04%,

B≤50 million-1,

moreover, the titanium with the goals of the firm reduce the grain size can be added and specially to bring its concentration to 0.04 wt.%.

To confirm the advantages of the preferred compositions of the alloy are references to the corresponding variation of implementation with regard to lithographic tape.

Structural properties of lithographic tape can improve in yet another variant of the method due to the fact that the lithographic tape before cold rolling is subjected to hot rolling and, if necessary, prior to hot rolling is conducted homogenizing treatment and/or during cold rolling carry out intermediate annealing.

The aforementioned task is solved according to another idea of the present invention also due to the method of manufacturing the basics of the printing form that has a topography, the maximum height of Rppeaks and/or Spwhich is not more than 1.4 μm, preferably not more than 1.2 μm, particularly not more than 1.0 μm, and made of the relevant invention lithographic tape.

In one of the preferred embodiments of the basics of the printing form she has a photosensitive coating thickness of less than 2 microns, preferably less than 1 μm. High roller ledges on the same lithographic plates has led, particularly when thin photosensitive coatings, printing defects, so in this case there is a significant improvement in the quality of printed forms. Prefer the Ino the basis of the printing form has a transparent photosensitive layer, that provides advantages in exploiting. When these layers for full coverage of the surface of the printing form is later printing, so the defective foundations of printed forms increase the cost. By improving the topography and the resulting reduction print defects caused by defects in printing costs can thus be significantly reduced.

The base plate may preferably have a width of 200-2800 mm, more preferably 800-1900 mm, in particular 1700-1900 mm and a length of 300-1200 mm, in particular 800-1200 mm

Corresponding to the invention, the base plate can be used preferably in CtP technology, i.e. for CtP printing plates. In CtP technology, the structure of the substrate surface plate is the most critical, because low patterns granulation or relatively thin photosensitive coating at high roller protrusions may lead to an increase in the number of printing defects. In addition, the CtP technology is often used transparent photosensitive layers with the previously mentioned problems. Due compared with the basics of printing plates of the prior art flat topography corresponding to the invention of the basics of the printing plate can, therefore, improve print quality and reduce costs.

Other characteristics and advantages of the STW of the present invention seen from the following further description of embodiments corresponding to the invention of lithographic sheet and corresponding to the invention method, with reference to the attached drawings. In the drawings shown

Fig.1 is a schematic representation of the procedure for determining the maximum height Rppeak and reduced height Rpkpeak according to DIN EN ISO 13 565,

Fig.2 - the option of implementing the invention method,

Fig.3 - the results of determining the surface topography of the lithographic tape after the last pass of the cold rolling,

Fig.4 - the profile shown in Fig.3 measuring the topography,

Fig.5 - the results of measuring the surface topography of the lithographic sheet of Fig.3 after carrying out variant implementing the invention method,

Fig.6 - profile shown in Fig.5 measurement of the topography,

Fig.7 - the results of measuring the surface topography of the lithographic tape after the last pass of the cold rolling,

Fig.8 - the results of measuring the surface topography of the lithographic sheet of Fig.7 after conducting the option of implementing the invention method.

Fig.1 shows a schematic representation of the procedure for determining the maximum height Rppeak and reduced height Rpkpeak according to DIN EN ISO 13 565.

In the left pane 2 Fig.1 marked the one-dimensional function Z(x) profile in the interval with bounds 0 and L. the Function Z(x) provides for ka is doy point x is Z(x), which corresponds to the local position of the actual surface, i.e. the deviation of the surface heights from the medium surface when the <Z(x)>=0 ám.

In the right pane 4 of Fig.1 applied the so-called curve ZAF(Q) 6 Abbot-Firestone (Abbott-Firestone). Under this curve refers to the cumulative probability density function of the profile Z(x) of the surface. It provides for percentage values of Q between 0 and 100% (plotted on the abscissa) the value of the altitude ZAFover which is appropriate portion of the surface. Curve ZAF(Q) Abbott-Firestone can therefore implicitly be described by the following equation:

Q=1LZ(x)ZAF(Q)dx(6).

L is the length of the measured profile Z(x), i.e. the value of the field of definition of Z(x). The integration domain is the part of the total length, which has the power inequality Z(x)≥ZAF(Q).

By conducting a tangent 8 through the inflection point of the curve 6 Abbot-Firestone, through the point of intersection of this tangent with 8 0% of line 10 and 100% of line 12 can in order to determine the Central region of the surface, the length of which is designated as the Central depth of the roughness Rk. Average height beyond the Central region of the elevations indicated as reduced height of the peaks Rpkand the average depth beyond the Central region of the depressions as reduced depth Rvkrecesses. In addition, in Fig.1 shows also the maximum height of peaks Rpthat corresponds to the removal of most of the high elevation from the mean at 0 μm.

The maximum height of peaks Rpor reduced the height of peaks Rpkin practice can be determined, for example, from the measured in different positions lithographic tape across the direction of rolling of the profile Z(x).

Reduced height Spkpeaks, in practice, may, respectively, be determined by the results of the measurement space. The calculation is similar to the reduced height of the peaks Rpkand the curve ZAF(Q) Abbott-Firestone for Spkin implicit form can be described by the following equation:

Q=1AZ(x,y)ZAF(Q)dx dy(7).

And - the value of the measured area, i.e. the size of the field of definition of Z(x,y). The integration region is part of the total area, which has the power equation Z(x,y)≥ZAF(Q).

Fig.2 shows a variant implementation of the relevant the invention, a method of manufacturing a lithographic tape. According to the method 20 of the first stage 22 is molded aluminum alloy, for example, AA1050, AA1100, AA3103 or AlMg0.5, preferably the alloy of the following composition (in wt.%):

0,3%≤Fe≤1,0%,

0,05%≤Mg≤0,6%,

0,05%≤Si≤0,25%,

Mn≤0,05%,

Cu≤0,04%,

the rest is Al and inevitable impurities, individually, a maximum of 0.05%), amounting to a maximum of 0.15%. Casting can be carried out continuously or periodically, in particular, by way of continuous, semi-continuous, in particular, periodic casting. To be used when necessary stage 24 of the molded product, i.e., in particular, cast ingot or cast tape, before further processing can be subjected to a homogenizing treatment, for example, in the temperature range 480-620°C for at least two hours. At a later stage 26 cast product is optionally subjected to hot rolling, preferably to a thickness from 7 mm to 2 mm Hot rolling, for example, in the manufacture of lithographic tape way dvuhnitochnogo casting can be eliminated. In the subsequent hot-rolled tape on the stage 28 is subjected to cold rolling, in particular, to a thickness of from 0.5 mm to 0.1 mm During cold rolling, if necessary, may occur intermediate annealing. After the last pass of the cold rolling lithographic tape on the stage 30 is subjected to a degreasing treatment with stage etching aqueous etching medium, which contains at least 1.5 to 3 wt.% a mixture of 5-40% of sodium tripolyphosphate, 3-10% of sodium gluconate, 3-8% non-ionic and anionic surfactants, and optionally 0.5 to 70% soda, and the concentration of sodium hydroxide in aqueous pickling environment is 0.1-5 wt.%, preferably 2-3,5 wt.%, a degreasing treatment with stage etching is carried out at a temperature of 70-85°C for 1-3,5 and surface erosion by a degreasing treatment with the stage of etching is set at the level of at least 0.25 g/m2.

Thanks to the chosen surface erosion high roller protrusions on the surface of the tape can be reduced so that the lithographic tape after a degreasing treatment with stage etching has a topography, the maximum height of peaks Rpand/or Spwhich is not more than 1.4 μm, preferably not more than 1.2 μm, particularly not more than 1.0 μm, and particularly suitable for CtP plates.

In Fig.3 presents the 3D measure the surface topography lithographic tape after the last pass of the cold rolling. The figure shows a three-dimensional view of the function Z(x,y) surface on a square region with a side length of 800 μm. For more information about elevation can be obtained located on figure 3 to the right of the scale. Y axis is parallel to the direction of rolling lithographic tape. It is seen that the lithographic tape along the rolling direction, i.e. along the y-axis has a high roll tabs, which can be recognized in the form of bright hills. These roller protrusions can prevent, and in some places even make impossible the application of the photosensitive layer, so the use made of this lithographic tapes basics of printing forms can be print defects.

Fig.4 shows the profile Z(x) reflected in Fig.3 measuring the topography, i.e. the cross-section of the measuring topography parallel to the axis X. you Can clearly see that the high ledges in the lithographic tape after cold rolling may have a height of more than 1.6 ám. These roll projections, however, have on the average roughness Ralithographic tapes only have a small effect.

In Fig.5 shows the results of measurements of the topography on the surface of the lithographic sheet of Fig.3 after conducting a variant implementation of the relevant invention of the method, i.e. after a degreasing treatment with the stage of etching according to the of the relevant invention method. In Fig.5 essentially shows the same region as in Fig.3. Fig.6 is the same as Fig.4 shows the related profile Z(x) reflected in Fig.5 measurement of the topography. Fig.5 and 6 show that in the degreasing treatment with stage etching is particularly high roller ledges can be drastically reduced. The maximum height of Rppeaks is only about 1.3 μm and, thus, significantly below the maximum height of peaks Rpraw corresponding to Fig.4 lithographic tape.

Therefore, using the appropriate invention of the method you can create the belt surface, the maximum height of peaks Rpand/or Spwhich is not more than 1.4 μm, preferably not more than 1.2 μm, particularly preferably not more than 1.0 μm.

To actually ensure that in the production of lithographic tapes are maintained to a maximum height of peaks Rpmay , for example, be three dimension across the direction of rolling, respectively on the edges and in the middle of the tape, and the length of the profile can be, for example, 4,8 mm Value of Spcan be determined based on measurements of the square of the square of the length of the parties to 800 microns.

As shown by comparison of Fig.4 and 6, a degreasing treatment with stage etching on the average roughness profile is R apractically no effect. This option, to which attention was drawn in the normal fabrication and characterization of lithographic tapes, therefore, unsuitable for demonstrating the presence of interfering roll edges in the lithographic tape. On the contrary, the surface quality lithographic tape better regulated in terms of roughness maximum height of peaks Rpand/or Sp.

In Fig.7 and 8 also presents the 3D measurement of the surface topography of the lithographic tape length 2146,9 μm and a width of 2071,7 μm, namely directly after the last pass of rolling (Fig 7) and after carrying out a degreasing treatment with the stage of etching according to the relevant invention of the method (Fig.8). Y axis again runs parallel to the direction of rolling lithographic tape. From the comparison of Fig.8 with Fig.7 it is clear that existing in Fig.7 high roller ledges along the rolling direction due to a degreasing treatment with the stage of etching can be highly reduced, therefore, creates a superior surface of a lithographic tape.

Lithographic tape with such a surface topography which is shown in Fig.5, 6, or 8, can be used as a particularly advantageous as the basis for printing forms with very low structures granulation and/or very thin photoacustic is lnyh coatings, as in CtP technology.

Other characteristics and properties of the invention can also be obtained from the following results of measurements of roughness on the options related to the invention of lithographic sheet.

Lithographic sheet, aluminum alloy which along with the production-related conditions impurities contains alloying components in the following proportions (in wt.%):

0,30%≤Fe≤0,40%,

0,10%≤Mg≤0,30%,

0,05%≤Si≤0,25%,

Mn≤0,05%,

Cu≤0,04%,

the rest of Al, were subjected to cold rolling to the final thickness of 0.14 mm 0,29 0,38 mm or mm With a degreasing treatment with simultaneous phase etching was set the same parameters as in the embodiment of Fig.2.

Before and after degreasing treatment roughness measurement was carried out on the upper sides of the lithographic tapes, namely, as in the marginal areas, and in the middle of the lithographic strips. When measuring the roughness was determined each time the average roughness Sathat reduced the depth of the grooves Svkthat reduced the height of the peaks of Spkand the maximum height of the peaks of Sp. Results for lithographic sheet of a thickness of 0.14 mm is presented in table 1.

Table 1
The measurement timeSaSvkSpkSp
Regional areabefore degreasing0,220,230,351,9
after degreasing0,210,270,331,0
The middlebefore degreasing0,210,260,351,6
after degreasing0,210,260,321,0

In the prior art to characterize the lithographic tapes still used the average surface roughness. Table 1 shows that this measure of roughness unfit to display the impact of the invention degreasing treatment with stage etching or surface quality lithographer the ical feeds for separate high roller ledges. Its value after a degreasing treatment with stage etching essentially unchanged. Reduced the depth of the grooves Svkalso clearly not suitable as an indicator for high roller ledges. In contrast, the figures for the maximum height of peaks Spreduced and, consequently, demonstrate improvement of the surface of the lithographic tapes in relation to preventing high roller ledges. Optimization of lithographic tapes, or method of their production on the basis of average roughness Spresults, therefore, a particularly low susceptibility to the above-mentioned print defects. The small height of the peak of Spkdue to degreasing treatment with the stage of etching is reduced and can be used as an additional measure of roughness.

Table 2
Sp(edge)Sp(middle)
Tape thicknessbefore degreasingafter degreasingbefore degreasingafter degreasing
0,14 m the 1,91,01,671,1
0.28 mm1,611,21,381,1
0,38 mm1,31,01,31,1

In table 2 the associated results for the maximum height of peaks Spfrom measurements of roughness on lithographic tapes of different thickness. In particular, corresponding to the invention is particularly advantageous for lithographic tapes with a thickness from 0.3 mm to 0.1 mm, as they directly after the last pass of the cold rolling have a relatively large excess of 1.5 μm values of Spand, therefore, subject to the above print defects. By a degreasing treatment with stage etching the maximum height of the peaks of Spcan be reduced when all of the measured indicators of the ribbon thickness is essentially the same size. Therefore, the surface quality of the thin lithographic tapes can be improved accordingly the present invention method is particularly strong.

The results in tables 1 and 2 show, in addition to the high roller ledges in particular are on the edges of the tapes. Therefore, a degreasing treatment with stage etching may occur, for example, and selectively in the outer region of the lithographic tapes.

Table 3
The measurement timeSaSvkSpkSp
Before degreasing0,220,230,431,51
After degreasing0,210,240,371,13

Table 3 outlines averaged lithographic tapes of different thickness indicators roughness Sa, Svk, Spkand Sp. The results clearly show that used so far to characterize the lithographic tapes average roughness Saunsuitable for improving the surface of the lithographic tapes in relation to preventing high roller ledges. On the contrary, the maximum height of peaks Rpand/or Spand the reduced height of the peaks Rpkand/or Spkafter abusir is living with stage etching is significantly reduced, therefore, lithographic tape and method of its manufacture can be significantly improved as a result of optimization in relation to the parameter Rpand/or Spunder certain conditions, in combination with Rpkand/or Spk.

For manufacturing corresponding to the invention of the lithographic tape may, for example, be used corresponding to the invention method. However, the invention of the tape is not limited to this method of manufacturing. On the basis of the present invention, the expert can by optimizing the parameter of roughness Rpand/or Spto develop other ways to obtain the invention, a lithographic tape.

1. Lithographic tape for an electrochemical granulation consisting of laminated aluminum alloy, characterized in that the belt surface has a topography, the maximum height of the peak of the Rpand/or Spwhich is not more than 1.4 μm.

2. Lithographic tape under item 1, characterized in that the belt surface has a topography, a reduced peak height Rpkand/or Spkwhich is not more than 0.4 μm.

3. Lithographic tape under item 1 or 2, characterized in that its thickness is from 0.5 mm to 0.1 mm

4. Lithographic tape under item 1, characterized in that it consists of alloy AA1050, AA1100, AA3103 or AlMg0.5.

. Lithographic tape under item 1, characterized in that it consists of an alloy of the following composition (in wt.%):
0,3%≤Fe≤1,0%,
0,05%≤Mg≤0,6%,
0,05%≤Si≤0,25%,
Mn≤0,05%,
Cu≤0,04%,
the rest is Al and inevitable impurities, individually, a maximum of 0.05%, amounting to a maximum of 0.15%.

6. Lithographic tape under item 1, characterized in that the proportion of doping impurities (wt.%) in lithographic tape the following:
0,3%≤Fe≤0,4%,
0,1%≤Mg≤0,3%,
0,05%≤Si≤0,25%,
Mn≤0,05%,
Cu≤0,04%.

7. Lithographic tape under item 1, characterized in that the impurity alloy lithographic tapes have the following maximum allowable percentage (in weight%):
Cr≤0,01%,
Zn≤0,02%,
Ti≤0,04%,
B≤50 million-1.

8. A method of manufacturing a lithographic tapes, in particular lithographic sheet according to any one of paragraphs.1-7, which consists of aluminum alloy lithographic tape is subjected to cold rolling and in which lithographic tape after the last pass of rolling is subjected to a degreasing treatment with a simultaneous stage etching aqueous etching medium, which contains at least 1.5 to 3 wt.% a mixture of 5-40% of sodium tripolyphosphate, 3-10% of sodium gluconate, 3-8% non-ionic and anionic surfactants, and optionally 0.5 to 70% soda, and the concentration of sodium hydroxide in aqueous pickling environment is 0.1-5 wt.%, characterized in that the surface is erosion due to degreasing treatment with a simultaneous stage etching is at least 0.25 g/m2.

9. The method according to p. 8, characterized in that the concentration of sodium hydroxide in aqueous pickling environment is 2-3,5 wt.%.

10. The method according to p. 8 or 9, characterized in that the temperature of the etching is 76-84°C and/or the concentration of sodium hydroxide in aqueous pickling environment is 2.6-3.5 wt.%.

11. The method according to p. 8, characterized in that the etching duration is 1-2 C.

12. The method according to p. 8, characterized in that the lithographic tape in the last pass of the cold rolling rolled to a final thickness of from 0.5 mm to 0.1 mm

13. The method according to p. 8, characterized in that as the aluminum alloy used AA1050, AA1100, AA3103 or AlMg0.5.

14. A method of manufacturing the basics of the printing form that has a topography, the maximum peak height Rpand/or Spwhich is not more than 1.4 μm, which is the basis of the printing form is made from lithographic sheet according to any one of paragraphs.1-7.

15. The method according to p. 14, characterized in that the basis of the printing form has a photosensitive coating thickness of less than 2 microns.

16. Application basics printing plate manufactured by the method according to p. 14 or 15 for CtP printing plates.



 

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