KR100489984B1 - Roll printing paper suitable for cold set printing and its manufacturing method - Google Patents

Abstract

A coated roll printing paper suitable for printing with cold-set offset printing inks is based on paper containing paper fibres and mineral filler and has a coating containing ground calcium carbonate (CaCO3) pigment in a synthetic binder. The novel features are that: (a) not less than 50 wt.% of the pigment is a natural ground CaCO3; (b) all the pigment has a fineness of not less than 80% being less than 2 mu m; and (c) the dry binder fraction is less than 13 wt.% with respect to the pigment. Also claimed is a method of making the paper.

Description

Roll printing paper suitable for cold set printing, and a manufacturing method thereof.

The present invention is a coating suitable for printing with a cold-set offset printing ink using a base paper as a carrier paper formed from a fiber material and a mineral filler and a coating comprising a calcium carbonate ground from a synthetic binder and a coating pigment as a binder. Related to roll printing paper. The present invention relates to the use of such papers and their manufacturing processes.

Currently, newspapers are almost all printed by an offset process using cold set inks. Compared to heat set inks they do not need to be exposed to heat for drying. Instead, the water of the printing ink emulsion and the oil in the ink are dried when absorbed by the carrier, i.e. paper, and the ink pigments remain on the paper surface. Oxidative drying also takes place here.

Although smoother carriers and smaller ink consumption improve the print quality, smoother papers are generally less absorbent, resulting in slower absorption of the ink emulsifier. This causes stains on the print press guides and deposits on the piles and folders of copies. Excessive absorption, on the other hand, further penetrates the ink into the paper, causing inadequate impressions, i.e. poor dot separation and printing on the back of the paper. Standard printing paper must satisfy the conditions for proper rapid drying of the cold set ink, but as is known the quality of the image on the printing paper is limited. Standard print paper is uncoated natural paper. Its pore volume is therefore not covered with a coating that can prevent absorption of the ink emulsion.

Newspaper rotary presses usually only work during certain times of the day. It is therefore reasonable to use these expensive facilities for other print jobs during this idle period. However, in booklet enclosures and the like, such work generally requires a higher quality printed image than in standard newsprint. Thus, there have been a number of experiments aimed at producing improved newsprint papers available for this purpose. They can penetrate SC (super calender) paper, ie high gloss paper fields used in headset offset printing. As coated paper they can penetrate the field of LWC (low weight coated) paper. However, previous experiments failed to be accepted in the market. European patent application 0 377 983 discloses coated newspaper papers suitable for use in cold sets with minimally needle-like pigments in coating pigments and exhibiting at least some oil absorption values. Such paper was not commercially available. Needle-like pigments such as Satin White, precipitated calcium carbonate and delaminated or structured kaolin are recommended but are very expensive. In addition, because of their structure, the use of the binder needs to be increased, thereby increasing the manufacturing cost.

It would therefore be desirable to provide a roll printing paper that can be economically produced, suitable for printing with cold set inks, is visually distinguishable from standard newspaper papers and can be processed on such printing machines at a printing speed common to that of offset printing of newspapers. It is an object of the present invention.

One feature of the present invention in achieving the above and other objects is a cold set offset using a coating comprising a synthetic binder as a binder and a ground calcium carbonate as a coating pigment and a base paper comprising a fibrous material and mineral filler as a carrier paper. The coated roll printing paper suitable for printing by the method is characterized in that the calcium carbonate is ground natural calcium carbonate, which accounts for at least 50% by weight of the coating pigment.

Another feature of the invention is characterized in that the total coating pigment has a powder degree of at least 65% and less than 2 μm and the proportion of binder as dry weight for the coating pigment is less than 13%.

Another feature of the present invention is a method of making a roll printing paper composition comprising a fiber material and a mineral filler, which base is coated with a coating color comprising pulverized calcium carbonate as a coating pigment and a synthetic binder as a binder. The preparation of coatings used for coating comprises at least 50% by weight of a coating pigment, which is ground natural calcium carbonate, the total coating pigment having an average powder degree of at least 65% of less than 2 μm, and the proportion of binder to 13% by weight of the coating pigment. Is less than

It has been found that the printability of the coated roll printing paper can be obtained with the cold set printing ink if the coating has an appropriate microcapillary phenomenon and affinity for the emulsifier of the cold set printing ink. These properties result in particles in which the coating pigment comprises a minimum proportion, i.e., 50% of natural milled (non-needle-shaped) calcium carbonate, and the total pigmentity of the coating pigment is at least 65% by weight of the pigment having a size of less than 2 μm. It can be obtained if the proportion of binder based on dry weight is less than 13% by weight of the coating pigment. Sufficiently fine grades of kaolin are known to provide high pigment porosity, but they need to have high binder usage because of their high specific surface area. This is especially true of kaolin that has been delaminated and pretreated. Calcium carbonate, on the other hand, has an inert hydrophobic surface and requires less binder in the coating.

The use of milled calcium carbonate in coatings is known from European patent application 0 377 983. However, it is only used as a blending pigment with the claimed needle-like pigment.

According to the present invention, the calcium carbonate used should have a high powder mediator such that the applied coating layer has a high microcapillary phenomenon to ensure fast drying of the cold set printing ink. The finer the capillary, the higher the capillary pressure, the faster the phase separation of the printing ink emulsified in some water. Coating pigments are 90 to 100% by weight calcium carbonate having a particle size of at least 80% of particles having a size of less than 2 μm or 75 to 85 weight 5 of a powder having at least 90% of particles having a size of less than 2 μm. Has calcium carbonate. Ink absorption time and water absorption capacity on the paper surface appear to be important for satisfactory drying of cold set printing inks. Two properties must be kept at least for satisfactory printing, but to some extent one property may be compensated for by another. Ink absorption time decreases as the fineness of the coating pigment increases but the water absorption capacity increases. At the same time, the specific surface area of the pigment increases with the degree of powder, thereby increasing the binder requirement. This reduces the preferred printing properties. One skilled in the art should find the best match between the powder of the coating pigment and the proportion of binder used.

Aluminum hydroxide is a particularly suitable blending pigment because of its form and powderiness. It can be used in proportions up to about 20% by weight of the coating pigment. Otherwise kaolin with a particle size of at least 65% of particles having a size of less than 2 μm may be used as a blending pigment as far as printability permits. Talc, titanium dioxide and gypsum are used as suitable blending pigments in small proportions as long as they do not adversely affect the capillary phenomenon of the coating.

Bentonite sodium is also good as a blending pigment with high water absorption capacity. 25% by weight of grades having a specific surface area of 600 m 2 / g are used and limited by the effect on the rheology of the coating pigments.

It is desirable to use a very active binder so that the cold setability of the coating is not reduced by too many binders. The following types of binders are commonly used for paper coatings: polymer dispersions (eg styrene-butadiene, acrylates, styrene-acrylates), polymer alcohols, proteins or casein, starch. Polymer binders and polyvinyl alcohols (PVA) are preferably used according to the invention in order to achieve high binding action with the lowest possible proportion of binder. PVA has the ability to bind reversibly to a surface that is quite inert, such as calcium carbonate, with binding capacity. Therefore PVA is preferably used in combination with plastic binders. According to the invention it is preferred to use less than 12% of the binder, in particular less than 9.5% by weight of the binder relative to the coating pigment. In general, the proportion of binder used is actually 6.5% by weight. If starch is also used, the nature of the binder is near the upper limit. Depending on the pigment mixture, a somewhat hydrophobic binder, starch or CMC (carboxymethyl cellulose) is used with PVA to control the ink absorption time.

Examples of binder combinations include 1.0 to 4.0 weight percent PVA and 4.5 to 5.5 weight percent synthetic binder, such as butadiene-styrene binder or styrene-acrylate binder. Polymeric dispersions in combination with PVA are considered very active binders. Addition of a crosslinker may be necessary for some binders.

Coating pigments according to the invention have the following typical components:

CaCO ₃ 65% <2 μm 50-100%

CaCO ₃ 90% <2 μm 50-90%

Kaolin 65% <2 μm 0-50%

Kaolin 80% <2 μm 0-50%

Al (OH) ₃ 98% <2 μm 0-20%

Bentonite Sodium 600㎡ / g 0-25%

Polymer binder 3-10%

PVA 0-5%

Protein 0-5%

Starch 0-5%

Coating pigments used may include useful additives such as melamine-formaldehyde resin as wet strength enhancer, up to 0.4% carboxymethyl cellulose (CMC) as a brightener in solution, and / or pH adjusters such as NaOH. Can be.

Crushed natural calcium carbonate suitable for the present invention is commercially available as a commodity such as C60HS, C70 and C90 HS from ECC International. The C60 HS grade has a proportion of 63 ± 3% by weight particles smaller than 2 μm, less than 2% by weight particles larger than 10 μm and less than 0.01% by weight particles larger than 45 μm. The C90 grade is 90 ± 3 wt% less than 2 μm, less than 1 wt% greater than 10 μm and less than 0.01 wt% greater than 45 μm. These grades are provided as slurries with a solids content of 78 ± 1% by weight. Omya is a moderately graded calcium carbonate manufacturer. The coating pigments according to the invention are processed in aqueous slurries with solids having a dry weight of 30-65% by weight. Applicable coating methods include doctor blade coating methods such as inverted blades, jet flow, roll coating systems such as Massey coating machines, film presses such as Jagenberg film presses, Beloit's Speed sizer or Metering size presses. Thus, the process of the present invention and the paper produced are independent of the nature of the coating process, even under one condition even if one coating method yields better results than the other. As you know, the doctor blade coating method smoothes the paper surface and provides varying coating thicknesses depending on the location, and the roll coating system provides a more uniform coating thickness that can be beneficial for ink absorption in some situations. Mild drying of the coating is also important. This is because the movement of the binder may damage the microcapillary phenomenon of the uniformly distributed coating.

The present invention considers the coating weight of a single coated paper to be at least 4 g / m 2 on both sides of the base paper. Preference is given to 7-12 g / m 2 coating weight on each side, in particular 8 g / m 2.

However, the present invention is not limited to a single coated paper. The present invention is also applicable to double coated paper. Double coatings have a coating weight per unit area of at least 15 g / m 2, in particular 20 g / m 2, on each side, the coating weight being equally divided between the two coatings. Top coat is important for the nature of the paper according to the invention. When referring to the coating without particular mention it is meant a single coating for a single coated paper and generally means a top coating of a double coated paper but may also mean an entire coating.

The first coat of the double coat is always called the first coat.

Top coat is very important for the properties of the double coated paper according to the invention. Therefore, the requirements and conditions described in terms of application to a single coated paper must be met. The first coat need not have the same powder or microcapillary phenomenon as the preferred embodiment of the coating described previously. However, even the first coat contains at least 50% by weight of ground natural calcium carbonate and has a dry weight ratio of binder for the coating pigment and the requirement for a total coating pigment having a particle size of at least 65% of particles smaller than 2 μm. Need to be less than 13%. The minimum requirements described above are also valid for single and double coated papers. This applies even if the top coat exhibiting preferred embodiments in composition and powderiness exceeds the minimum requirements and the first coat does not necessarily meet the minimum requirements. It may be practical to pre-smoothe the base before applying a single coating or the first coating, such as in a smooth machine at the end of a paper machine where a "soft-nip" can be equipped.

The present invention is not limited to the use of special paper. Paper with or without wood chips can be used and paper with a significant proportion of recycled paper fibers can be used. For example, 78% chemical pulp; 20% mineral filler consisting of 15% calcium carbonate, 2.5% kaolin and 2.5% talc; Raw materials free of crushed wood in raw materials with 1% starch and 1% other additives are suitable.

However, due to cost, paper containing wood pulp and a certain amount of recycled waste paper is preferred. In general, base paper containing groundwood pulp has the advantage of printing at higher opacity. The fiber content of the base paper, including groundwood pulp and waste paper, may be 20% chemical pulp, 20% groundwood pulp and 60% waste paper as dry matter for the entire fiber. This material may contain up to 50% mineral fillers based on fiber content, and the filler may be the material. As you know, this proportion of filler material does not remain entirely on paper and some enter wastewater.

When the ground wood fiber is referred to as the fiber component, the term applies to all materials in the papermaking art which means ground wood pulp, thermal wood pulp (TMP), and thermochemical wood pulp (CTMP).

A requirement for printing with cold set inks with satisfactory ink drying is the dimensional stability of the paper. Since water from cold set ink penetrates not only the coating but also the base paper, it affects the bonding between fibers and the dimensional stability of paper. This effect is greater than that of ordinary newspapers. Paper accounts for a smaller proportion of weight when coated paper having a weight per unit area comparable to the coating is used as a carrier for the coating. That is, the base paper is thinner. The dimensional stability of the paper exposed to moisture can be improved by additives such as starch. Therefore, it is common sense to add about 0.5% starch to the raw material. Paper made on an open Fourdrinier or "hybridizer" carrying a Fourdrinier screen only after the top dewatering screen is formed may have dimensional stability suitable for use in cold set printing without starch addition to the paper. Because of this manufacturing method they have a fiber orientation of 1: 2 up to 1: 2.5 which is a fairly preferred aspect ratio. Since the fibers are oriented primarily in the manufacturing direction, i.e. in the long direction of the paper, the deficiency in dimensional stability appears to be transverse shrinkage, which is increased by the tension of the paper in the printing press.

Large-scale printing paper is currently produced on high-speed Foudrinier machines, in which state-of-the-art "gap formers" are used in which sheets are formed in the gap running between two screens. Papers made on these state-of-the-art machines have poor transverse / vertical fiber orientations of about 1: 3 to 1: 4. This causes the paper to have worse lateral stability. According to the invention the dimensional stability of the paper produced on the gap former is improved by adding at least 1%, up to 2%, and generally 1.5% of starch to the input material. A surprising feature is that the paper, including high starch, can be made in a gap former, not the effect of starch on the paper. This is made possible according to the invention with modified and highly positive starch. The surprising effect is that about 1.4% of the starch was added to the input material when 1.5% of the starch was added to the input material, which shows that the starch has a very high retention of starch in sheet formation. Higher starch ratios on the input material do not have a significant impact on the raw material and, at best, increase wastewater load and cost. When tested with very positive starch, paper could be produced at a rate of 1220 meters / minute without reducing the machine speed.

For cold set ink printing paper, a study of measuring measurable paper properties has been conducted to determine the suitability of the paper. It has been found that the limits in ink absorbency, in particular the limits of surface wettability, are important. In the company of the present inventors a modified absorption test was used to measure the ink absorbency. This test uses a multipurpose test printer (Dr. Durner System, "Prufbau Dr. Ing. Herbert Durner", peisenberg). Surface wettability is measured as a time dependent decrease in the contact angle of droplets lying on the surface. FIBRO 1100 Dynamic Absorption Tester (FIBRO-System AB, Stockholm) is used. Test procedures are attached as Appendix A and B.

The test prints are made with standard printing inks under defined conditions in the absorbency test. After a certain period it is compressed with supporting paper. The ink concentration delivered to the supporting paper is measured with a densitometer. The following data shows the concentration for supporting paper after 30 seconds.

Distilled water was used for contact angle measurements to determine standard wettability. The contact angle measured after 2 seconds with the FIBRO tester is recorded next.

It has been found that ink absorbency is important for suitability for cold set printing processes. It should be less than 1.1, in particular less than 0.8. The contact angle measured after 2 seconds with a FIBRO meter should be less than 70 °, in particular less than 55 °. For example, a standard newsprint has a value of 42 ° after 2 seconds. Such natural paper has high wettability. The two species mentioned above balance each other. For example, a two second contact angle of 45 DEG and an absorbency of 0.5 on both sides of the paper result in excellent printing. Papers with a contact angle of less than 50 ° and an absorbency of less than 0.7 are suitable for cold set printing.

The paper according to the invention is essentially a paper with a Bekk smoothness value of 10 to 50 seconds which is not glossy or slightly glossy. These are mat grades. The high gloss on paper according to the present invention reduces the picking resistance of the surface necessary for printability and can result in the loss of microcapillary phenomenon required for cold set ink drying.

The term "otro" refers to an oven dried state.

Example 1

The following raw materials are used to produce paper at a machine speed of approximately 1200 meters / minute on a high speed Fourdrinier machine with a double screen former (gap former):

Application fee

12.3% groundwood pulp

Chemical Pulp 13.0%

Abolition 40.0%

Filling 33.0%

High starch 1.5%

0.2% preservative

Ground test data

Weight per Unit Area 40.3g / ㎡

Filling ratio 15.2%

Vertical Break Stress 41.8N

Transverse Break Stress 11.8N

Fiber orientation (landscape aspect ratio) 1: 3.5

Brightness 73.5%

1.538 cm3 / g

Example 2

The base paper prepared according to Example 1 is coated with a coating having the following composition.

Natural CaCO ₃ , 95% <2㎛ 80%

Al (OH) ₃ , 98% <2 μm 20%

                                    100%

Binders and Additives Based on Coating Pigments

Styrene-Acrylic Binder 10%

Professional solution 3%

0.25% CMC (carboxymethyl cellulose) solution

Melamine-Formaldehyde Resin 0.8%

Varnish 1.3%

This coating has a weight per unit area of about 8 g / m 2 per side. The following measurements were made on the finished paper:

Weight 56.6g / ㎡ per unit area

Ash 35.3% when burned at 600 ℃

1.18 cm3 / g

Bekk smoothness (top) 22 seconds

Beek smoothness (bottom) 15 seconds

2 second contact angle (FIBRO measuring instrument) 58。

Absorbent 0.42 in 30 seconds

Cold set suitability, that is, proper ink drying of the present paper, was satisfied.

Example 3

The base paper according to Example 1 is coated with a coating having the following composition:

Coating Pigment

Natural CaCO ₃ , 90% <2 μm 100%

Binders and Additives for Coating Pigments

Butadiene-Styrene Binder 5.0%

PVA solution 3.5%

Melamine-formaldehyde resin 1.3%

Polishing 1.3%

This paper has the following surface properties:

2 second contact angle (FIBRO measuring instrument) 45。

Absorption value 0.50 after 30 seconds

Other test data is the same as the paper of Example 2. The paper produced in this example showed significant cold set suitability.

Example 4

The base paper prepared in Example 1, instead of the polyacrylate dispersant, the pigment became a cationic pigment slurry with a high amine content positive dispersant and the cationic polymer binder was coated using the coating pigment used to prepare the coating pigment. The finished paper had the following surface properties:

2 sec FIBRO contact angle 50。

Absorbent 0.39 / 0.47 after 30 seconds

The printability of this paper in the cold set process was very good.

Example 5 (comparative example)

The base paper prepared in Example 1 was coated with a coating pigment having the following composition:

Natural CaCO ₃ , 90% <2 μm 80%

Kaolin, 80% <2 μm 20%

100%

Binders and Additives Based on Coating Pigments

Styrene-Butadiene Binder 9.5%

Starch solution 7.0%

0.25% CMC solution

Melamine-formaldehyde resin 0.8%

Polishing 1.3%

This coating pigment coated paper had the following surface properties:

2 sec FIBRO contact angle 72。

Absorption after 30 seconds 1.11 / 1.19

Ink drying was not satisfactory when printing with cold set ink. This is due to the surface properties and the high proportion of binders.

Pigments coated with 20% Al (OH) ₃ , 98% <2 μm in place of 20% kaolin in the coating pigments gave poor print results. The composition and ratio of the binders were the same.

The paper produced in Examples 3 and 4 was processed on a cold set printing press at normal production speed to show accurate image reproducibility with normal ink dryness. At the same time, ink consumption was less than newspaper paper. Water usage was also reduced. Higher whiteness compared to ordinary newspaper paper resulted in more contrast printing compared to low weight coated mat grades.

FIBRO 1100 DAT is the organization name for Fibro System AB (Stockholm S-12609, PO Box 9081). DAT is a "dynamic absorbency meter". This instrument is used to measure surface wettability. This is a paper characteristic that must be accurately measured and controlled for processes such as coating and printing. It is based on contact angle measurements and on methods developed by the Swedish Paper Research Institute.

The instrument includes a medical dropping system and a CCD (charge coupler) camera, the drop size is adjustable from 0.1 to 9.9 μl and the change in droplet deposited on a paper sample characterizing wettability can be stored in a 20 millisecond cycle time. Appears as a video image. The change in contact angle over time can be graphed so that the wettability of different paper samples can be easily compared with each other.

Distilled water is used herein for wettability determination and wettability was measured after 2 seconds.

In a counter pressure measurement called the absorbency test, a specified amount of printing ink is placed on a strip of paper. The cross section of the strip is then wound on the supporting paper strip at the specified intervals. The amount of ink transferred to the supporting paper strip is optically measured. These allow for ink absorption and alluvability of the sample strip.

Details of the test procedure are described in the multipurpose test print press (Prufbau, Dr.-Ing. Herbert Durner, Aich 17-23, D-82380 Peissenberg / Munich, dated 26 September 1972). See in particular Figures 10.5 and 14.2.

This apparatus recommends 0.3 cm 3 ink for coated paper, 30 sec ink dispensing time in the dispensing roller, and 30 sec for printing. Both the printing pressure and the counter pressure are 200 N / cm, ie 800 N for a print type width of 4 cm. Absorption test No. 52 006801 from Michael Huber Ink Factory (Munich) shall be used. The counter pressure should be applied after 30, 60, 120 and 240 seconds. Recommended press speed is 0.5 meters / second. A standard paper called APCO II / II (Scheufelen Company) is used as the test print paper.

Tests were conducted herein at the values stated but at twice the printing speed. Ink delivery to the support strip caused by the counter pressure for 30 seconds was especially evaluated.

German priority application 196 01 245.7 alc 296 01 859.7 is incorporated by reference.

Claims (29)

Paper containing fiber material; And A coating composition formed on said base paper containing a coating pigment and a binder, Wherein the paper is smoothed or polished with a machine with a Bekk smoothness value of 10-50 seconds, Wherein the coating pigment comprises calcium carbonate, Wherein the ink absorption test provides a value of less than 1.1, Coated roll printing paper suitable for printing with the cold set offset method. The coated roll printing paper of claim 1, wherein the surface wettability of the coated roll printing paper provides a value of less than 70 ° after two seconds by contact angle measurement according to the Fibro test. The coated roll printing paper of claim 2 wherein the contact angle provides a value of less than 55 ° after 2 seconds. The coated roll printing paper of claim 1, wherein the base paper further comprises a filler. 5. The coated roll printing paper of claim 4 wherein the base paper comprises up to 18% by weight of mineral fillers relative to the oven dried paper fibers. The method of claim 1 wherein the binder composition is dry weight with respect to the weight percent of the coating pigment, 3-10% synthetic binder, 0-5% polyvinyl alcohol (PVA), 0-5% protein; And Coated roll printing paper characterized by containing 0-5% starch. 7. The coated roll printing paper of claim 6 wherein the protein comprises casein. The coated roll printing paper of claim 1 wherein the coating pigment further comprises one or more additional coating pigments. 9. The coated roll printing paper of claim 8 wherein the additional coating pigment is selected from the group consisting of aluminum hydroxide, kaolin, talc, titanium dioxide, gypsum, and bentonite sodium. 10. The coated roll printing paper of claim 9 wherein the coating pigment comprises up to 20% by weight of aluminum hydroxide having a powder degree of at least 95% of particles having a thickness of less than 2 μm. The method of claim 9 wherein the coating pigment Kaolin with a powderiness of at least 65% of particles having a particle size of less than 2 μm up to 50% by weight; Aluminum hydroxide having a powder degree of 95% of particles having a particle size of less than 2 µm up to 20% by weight; And Coated roll printing paper comprising 25% by weight of bentonite sodium. 10. The coated roll printing paper of claim 9 wherein the coating pigment contains 20% by weight aluminum hydroxide having a powder degree of 95% particles less than 2 microns. The coated roll printing paper of claim 1, wherein the weight per unit area of coating is at least 5 g / m 2 per side. The coated roll printing paper of claim 1, wherein the weight per unit area of coating is 7-12 g / m 2 per side. The coated roll printing paper of claim 1 wherein the weight per unit area of coating is at least 15 g / m 2 per side. The coated roll printing paper of claim 1, wherein the weight per unit area of coating is 20 g / m 2 per side. The coated roll printing paper of claim 1, wherein the base paper comprises at least 1.0% by weight of cationic starch. 18. The coated roll printing paper of claim 17 wherein the base paper comprises at least 1.3% by weight cationic starch. The method of claim 1, wherein the calcium carbonate comprises at least 50% by weight of the coating pigment; The coating pigment has a powder degree of at least 65% of particles smaller than 2 μm; Coated roll printing paper, characterized in that the ratio of binder to coating pigment is less than 15% by weight as dry weight. The method according to claim 19, wherein the coating pigment comprises 50 to 60% by weight calcium carbonate having a powder degree of 60% or more particles less than 2㎛, the remainder of the pigment is less than 2㎛ the average powder degree of 80% or more Coated roll printing paper characterized by having. 20. The coated roll printing paper of claim 19, wherein the average pigmentity of the coating pigment is at least 80% of particles having less than 2 microns. 20. The coated roll printing paper of claim 19 wherein the ratio of binder to coating pigment is less than 12% by weight. 20. The coated roll printing paper of claim 19 wherein the ratio of binder to coating pigment is less than 9.5% by weight. 20. The method of claim 19, wherein the binder is in proportion to the coating pigment. 1.0-4.0 weight percent PVA; And Coated roll printing paper, characterized in that it comprises a synthetic binder selected from the group consisting of 4.5 to 5.5 wt% butadiene-styrene binder and styrene-acrylate binder. The coated roll printing paper of claim 1 wherein the ink absorption test provides a value of 0.8 or less. The coated roll printing paper of claim 1 wherein the calcium carbonate is not needle-shaped. Providing a base paper containing fiber material; And Coating the base paper with a coating pigment comprising calcium carbonate, and a coating composition comprising a binder, Wherein the paper is characterized in that the ink absorption test provides a value of less than 1.1, Process for making coated roll paper suitable for printing by cold set offset method. 28. The method of claim 27, wherein the base paper further comprises a mineral filler. 28. The method of claim 27, wherein the surface wettability of the coated roll printing paper provides a value of less than 70 ° after 2 seconds by contact angle measurement according to the Fibro test.