SK124799A3 - Paper sized with 2-oxetanone sizing agent made from normal and branched fatty acids - Google Patents

Abstract

The present invention relates to a method of manufacturing a paper grade containing precipitated calcium carbonate as filler. According to the invention, the ink-jet printability of said paper grade is advantageously improved by using a 2-oxetanone size which is made starting from non-branched and branched-chain fatty acids having main chain comprising 6-22 carbons linked with each other by saturated bonds.

Description

Paper sized with 2-oxethanone-based sizing agent prepared from normal and branched fatty acids

Technical field

The present invention relates to a process for the production of an additive type of paper using alkaline hydrophobizing glues. The glues used have reactive functional groups that can form covalent bonds with the cellulose fiber. The bound hydrophobic chains are thus directed from the outside of the cellulose fiber.

BACKGROUND OF THE INVENTION

The production volumes of fine paper types, which are produced in an alkaline manner, are rapidly increasing due to the use of crystalline calcium carbonate, which increases the paper's resistance to aging and maintains its gloss. Its further advantage is to increase the proportion of circulating water in the paper machine.

Simultaneous use of fine types of paper for printing (eg contactless method, especially inkjet printing) places particular emphasis on sizing. Conventional types of office paper are expected to be largely usable and suitable for a variety of copiers and printers, including inkjet printers. However, they do not yet meet the requirements of the so-called. multipurpose types of office paper, i. high-quality printing, both for both types of printers (inkjet and laser) and for copying machines (Wochenblatt fur Papierfabrikation, 10,1996,0. Malstrôm, K.H. Maier, "Leimungsstrategien fur PCC-haltige Buropapiere").

Inkjet printers design uses two basic printing technologies with permanent ink jet or discrete drop formation. Inkjet printing is currently used in a wide range of applications; from black and white office printers to photo-quality four-color printers, real-time identification and marking equipment, and large format plotters printing on sheets or continuous paper. Inkjet printers have the highest number of different uses compared to other types of contactless printers, and are particularly prized for color and fast printing capability. Compared to other methods, inkjet printing also has a low cost.

The printing process on an inkjet printer can be easily controlled by a computer, making all data processing techniques readily available. For example, color control or color balance can be easily controlled.

Based on the experience gathered about inkjet printing, it can be said that its quality is influenced by the fiber composition of the paper, i. especially the ratio of coniferous and deciduous trees. As with the quality of the paper produced, the structure and topography of the pores is critical to the result of inkjet printing. The print quality is determined by the incompressible sheet texture and other parameters that characterize the ability of the sheet to absorb ink in terms of paper quality. The type of inkjet paper should absorb ink sufficiently, but so that the ink can dry quickly enough before it begins to spread along the fibers or into the pores in the sheet structure. Chemical interactions between the ink and the sheet surface are therefore important in the inkjet field.

In addition to the basic factors related to the structure of the paper, the quality of the inkjet printing can be influenced by the additives used in the manufacture of the paper (e.g. hydrophobizing internal glues and internal sizing formulations, surface sizing starches and pigments for highly specific surfaces).

Paper sizing formulations have been developed to modify the chemical properties of the surface and to improve the quality of monochrome monochrome printing through the increased hydrophobicity of the paper. By increasing the hydrophobicity of the paper, better black ink printing results have been achieved, due to improved capillary force control of ink absorption into the sheet structure, both sideways and inwards. This approach resulted in sharply bounded edges of the printed pattern and reduced black ink spreading across the sheet.

The most commonly used size formulations that are suitable for the alkaline fine paper process are based on alkenyl succinic anhydrides and alkyl ketone dimers (DAK). Both types of sizing have reactive functional groups capable of forming a covalent bond with the cellulose fiber so that the hydrophobic chains extend away from the fiber. The nature and orientation of these chains make the fiber water repellent. Alkenyl-succinic anhydride-based glues and DAK are dispensed as a slurry at the wet end of the paper machine. The actual sizing process takes place in the drying section and rolling mill.

Commercially available DAK-based glues containing one β-lactone ring are prepared by dimerization of two straight chain fatty acid chlorides. The most commonly used DAK-based glues are prepared from palmitic acid and / or stearic acid. Alkenyl succinic anhydrides (ASA compounds) are obtained by reacting long chain olefins (C 18 -C 18) with maleic anhydride. In order to achieve higher hydrophobicity of the paper in internal sizing, it was necessary to add higher doses of alkenylsuccinic anhydride and DAK-based glues to the paper machine. This, however, worsened the work of the machine and increased problems with the occurrence of various types of contamination.

Unfortunately, the method of increasing the degree of hydrophobicity for controlling black ink in printing does not provide optimal results in color printing. In this way, it is possible to improve the ink drying, which can increase the print density. However, in color printing, the amount of ink used is higher than in black and white. This, together with higher absorption has frequently caused any inconvenience to the lack of slow drying of printed color inks, resulting the spreading ua mixing ut * _t · overlapping colors to printed sheet (known as color bleeding).

For these reasons, various attempts have been made to improve the quality of color inkjet printing, e.g. by varying the amount of fillers with a higher specific surface area. Another possibility to influence the print quality on paper is to use surface sizing.

To date, various methods have been proposed for improving the absorbency of the sheet and for a balanced degree of hydrophobicity that is sufficient for inkjet printing. However, alternative methods of producing fine, alkaline paper grades having optimum properties for multi-color inkjet printing are still being sought.

Description of the invention

Good inkjet print quality is achieved with those types of paper that are produced under neutral or alkaline conditions with the addition of additives (especially crystalline calcium carbonate as a filler), achieved by using a 2-oxethanone-based glue. These oxetanones are produced from one or more fatty acids having a saturated backbone containing 6 to 22 carbon atoms, of which at least one has a branched carbon chain.

The use of 2-oxethanone-based glues in papermaking has been known for a long time (e.g., US Pat. No. 2,627,477 and Tappi, 39 (1), 1956, JW Davis et al., "A new sizing agent for down-alkylketene dimers"). "). However, there is no mention in the literature of the use of 2-oxethanes prepared from saturated fatty acids, of which at least one has a branched carbon chain.

Like conventional DAK-based glues, these new glues can be prepared from fatty acids. It is essential that at least one fatty acid has a branched carbon chain, but which does not contain any double bond. The length of this carbon chain in the starting fatty acid may be between 6 and 22 carbon atoms.

According to one aspect of the invention, it has been found that, in particular, mixtures of linear and branched chain fatty acids (e.g. in a 50:50 ratio) provide optimum properties for the type of paper to be used for inkjet printing. This paper can therefore serve as a "multipurpose" paper. In terms of paper production, it should be emphasized that the amount of sizing required to achieve the desired effect will be lower in the case of the novel process than with conventional sizing formulations. This will lessen the problems of contamination and adherence of impurities caused by the presence of sizing in the paper machine.

The invention also relates to a type of paper in which 2-oxethanone-based sizing is used, which is produced from fatty acids, at least one of which comprises a branched carbon chain. The paper may comprise alum and crystalline calcium carbonate.

Stable emulsions of novel sizes may be prepared by the same procedures as standard emulsions based on DAK.

The type of paper produced according to the present invention is generally sized by adding at least 200 g, more preferably at least 600 g and most preferably 1 kg of glue per ton of paper. This type of paper is best suited for inkjet printing, but can also be used for copiers and laser printers ("multipurpose" paper).

One type of sizing formulation according to the present invention is a 2-oxethanone-based sizing agent made from 16-methylheptadecanoic acid or a mixture of fatty acids, preferably containing at least 40% 16-methylheptadecanoic acid or some other branched carbon chain fatty acids.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

To evaluate this method, test sheets with a basis weight of 80 g / m @ ² were prepared using a standardized SCAN test method using a water-circulating sheet, wet pressing and a drying cylinder. The pulp was prepared from birch and pine pulp (60:40 ratio), Raisamyl 135 ESP internal sizing starch (manufactured by Raisio Chemicals Oy, 0.3% fiber weight), filler (crystalline calcium carbonate, 22% weight) sheet) and retention aid (0.16% of the total fiber weight). The internal glues were added to the cellulose slurry in amounts of 0.06, 0.12 and 0.20% by weight of the fibers.

The prepared test sheets were subjected to the Cobbôo water absorption test and the Schröder ink penetration test immediately after drying, the next day before curing and after drying and curing. The curing of the test sheets was done in a heating chamber (10 minutes at 105 ° C).

A common conventional DAK-based sizing agent (Raisafob 5105) was used in this example as a comparative sizing formulation. DAK-based sizing agent derived from 16-methylheptadecanoic acid was dispersed in the same manner as conventional DAK-based sizing agent using cationic starch.

Table 1

acid 60:40 palmitic / stear ratio 0.06 0.12 0.20 65 18.7 15.0 37 15.9 14.0 34.1 16.3 13.9 5 > 1000> 1000 25 > 1000> 1000 27 > 1000> 1000 acid 40:60 palmitic / stear ratio 0.06 0.12 0.20 29.8 3.17 16.3 23.1 16.0 12.8 26.1 6.15 14.6 47 > 1000 > 1000 70 > 1000> 1000 112 > 1000> 1000 DAK-based glues derived from 16- methylheptadecane (100% branched chains) 0.06 0.12 00:20 through 70.0 45.6 through 55.0 33.4 through 52.3 32.3 0 0 10 0 0 22 0 2 25 DAK-based glues derived from 16- methylheptadecane (50:50 ratio of branched and unbranched chains) 0.06 0.12 0.20 through 22.8 17.3 through 24.7 16.2 through 19.8 15.7 0 165 775 0 137 > 1000 0 217 > 1000

The results shown in Table 1 show that DAK-based sizing derived from 16-methylheptadecanoic acid (50:50 branched and unbranched chain ratio) provides comparable sizing quality to conventional palmitic-stearic sizing.

Example 2

Different types of DAK-based glues have also been evaluated on a pilot mill paper machine at a speed of 60 m.min ^-1 (4.1 kg.min ^-1 ), which produces a fine type of paper weighing 80 g.m ^-2 .

The blend for the pilot plant tester contained birch and pine pulp (75:25 blended), which was ground to a Shopper Riegler index of 25, filler (crystalline calcium carbonate, 22% by weight of paper), Raisamyl 135 internal sizing starch (manufacturer) Raisio Chemicals (0.5% fiber weight) and a retention aid (0.22% total fiber weight).

The internal glues were added to the pulp in amounts of 0.15 and 0.20

I * t i 'I% the weight of the fibers. Raisamyl 408 SP (manufactured by Raisio Chemicals, in an amount of 8% based on dry weight) was used as the surface sizing.

The hydrophobicity of the sheet produced on a pilot plant paper machine was evaluated using the Cobb ' water absorption test on samples taken directly from the Pope Winder, which were treated 10 minutes before the test. The hydrophobicity of the sheet produced on a pilot mill paper machine was further evaluated on rolling-cured specimens in both the Cobbôo water absorption test and the HST ink penetration test. Hubble evaluates ink penetration into the sheet. The method is based on monitoring the reflectance of the ink spot over a given time, e.g. the time during which reflectance is reduced to 80% of its original value. The usability of ink samples for inkjet printing has been tested on a commercially available inkjet printer (manufactured by Hewlett-Packard). We bleed and bleed the colors on the printed test sheets were assessed visually, using an image analysis device and measuring the optical density of the color printed areas.

Table 2

acid 60:40 palmitic / stear ratio 50.3 41.9 38 0.13 0.20 23.2 19.3 345 acid 40:60 palmitic / stear ratio 0.13 0.20 52.0 19.9 43.3 18.9 27 385 acid-based DAK-size 16-methylheptadecane (100% branched chains) 0.13 0.20 57.7 39.9 48.1 33.3 12 54 acid-based DAK-size 16-methylheptadecane (50:50 ratio of branched and unbranched chains) 0.13 0.20 51.5 20.2 42.6 19.2 33 355

The results shown in Table 2 show that DAK-based sizing derived from 16-methylheptadecanoic acid (50:50 branched and unbranched chain ratio) achieves a comparable degree of hydrophobicity as conventional DAK-based glues.

Table 3 f? i '. ^From .

- <qt <lg i

/ · X · * - jx · - 5 ^{ς J} : * · * ·· - 'Λ ζ I t b > % í ^Λ /> í ΐ / h *; ' ¹

black and white Inkjet press drying time bleeds density 7 6.5 1.38 8 6.3 1.44 immediately 10 1.1 6 5.5 1.42 Full color press bleeding area print circumference print density> (aema) 7.4 50749 2045 1.24 7.5 51850 2016 1.28 6.5 49595 1949 0.98 t ‘ 6.5 48440 1905 1.27 Surface glue consumption [l.mm ¹ ] 1.51 1.43 1.60 1.33

The results shown in Table 3 show that DAK-based sizing derived from 16-methylheptadecanoic acid (50:50 branched and unbranched chain ratio) achieves an optimum balance in monochrome printing between parameters that characterize the thickness of the printed contours (bleeding, spreading, area and perimeter of the test pattern) and glue consumption. In addition, the advantage of the glue prepared according to the present invention is that it is neither necessary to add conventional hydrophobizing agents nor to use other techniques to increase the surface hydrophobicity.

Example 3

The internal size sizing agent prepared according to the present invention, in particular DAK-based sizing agent derived from 16-methylheptadecanoic acid (50:50 branched and unbranched chain ratio), achieved the best results in laboratory and pilot plant tests. Its further testing was carried out on an industrial scale on a paper machine for the production of fine paper. Comparative samples were made using conventional DAK-based glues. The composition of the paper produced was identical to the typical types of fine paper which contain crystalline calcium carbonate and were therefore suitable for inkjet printing. The basis weight of the paper produced in the test was 70 g / m @ ² . The size was added at 1.3 kg per ton of paper.

The test sheets were taken from several packages that were produced during the trial operation. Hydrophobicity (Cobbeo and HST) and parameters characterizing usability for inkjet printing (bleed, bleeding and optical densities) were tested on the top of the test sheets.

Table 4

Cobb 0 µg-m ² test 22.2 28.8 HST [s] surface 86.5 54 Inkjet printing we are spreading on the surface bleeding on the surface J 2 4 2 Inkjet printing black black, combined cyan červenofialová yellow 1.84 1.10 1.37 0.93 0.91 1.4 1.13 1.36 0.92 0.88

Comparing the applicability of 16-methylheptadecanoic acid-based DAK-size sheets to commercially available size-sized sheets

II D-AK glues for inkjet printing (according to the results shown in Table 4) show that the 16-methylheptadecanoic acid D-AK glues provide a clearly better result for both black and color printing. The paper that was glued with 16-methylheptadecanoic acid-based DAK-size showed neither ink penetration of the sheet, nor bleeding or bleeding. In addition, the density of the printed ink was significantly better than that of paper samples that were sized with commercially available DAK-based glues. Thus, high sheet quality suppression was achieved even without hydrophobizing the sheet surface.

Industrial-scale tests have proven that test paper is not only suitable for inkjet printing, but also meets the additional requirements for “multipurpose” paper, such as a sufficient degree of hydrophobicity for copiers and laser printers. The work of the machine was faultless during the test and there was no sticking of dirt or contamination of the surface of the paper machine components.

Example 4

In this example, the paper type was surface treated. For this treatment, a certain degree of hydrophobicity has already been achieved by internal sizing in the pulp phase of papermaking. According to the test Cobbôo hydrophobic effect was achieved at the level of 30 grams per square meter ^'second The surface sizing was performed on a Helior, in which a sheet of paper is deposited on a rotating roller and the surface sizing starch is applied together with the admixed surface hydrophobizing agent using the selected coating knife pressure.

In this case, the surface sizing was carried out with a 10% oxidized cationic starch solution for the surface sizing of Raisamyl 406 SP (manufactured by Raisio Chemiclas Oy). This solution containing 10% starch was mixed with surface sizing additives in amounts relative to the active ingredient in the dry starch. The following surface sizing additives were tested: DAK based on a mixture of 16-methylheptadecanoic acid and stearic acid, styrene-acrylate copolymer and styrene-maleic anhydride copolymer. The ratio of 16-methylheptadecanoic acid and stearic acid in the surface sizing glue was 1: 1. Raisafob P400 (manufactured by Raisio Chemicals Oy) was used as a surface sizing additive based on styrene-acrylate copolymer. Raisafob D100 (manufactured by Raisio Chemicals Oy) was used as a surface sizing additive based on styrene 12 maleic anhydride copolymer.

The results of the tests are shown in Table 5 below, where the sizing quality is represented by the Cobbeo and HST values.

Table 5

Paper mixture 0 30.4 67 Mixture + starch for surface sizing 0 46.6 60 DAK based on acid 0.5 22.4 126 16 AKD 1 22.4 137 and stearic acid 2 20.4 140 4 20.0 182 Styrene-acrylate 1 41.6 65 copolymer 2 39.2 69 4 36.0 78 styrene 1 38.4 75 maleic anhydride 2 29.2 115 copolymer 4 21.6 117

The values in Table 5 show that DAK-based glues prepared from fatty acids containing 16-methylheptadecanoic acid exhibit the best properties even at the lowest addition rates. These glues achieve the highest hydrophobicity according to Cobbeo and Hubble results.

The results of the tests that were used to evaluate the black and white print quality are shown in Table 6 below. The optical print density on paper samples was measured (Hewlett-Packard 500 C inkjet printer).

Table 6

Paper mixture 0 1.33 0.98 Mixture + starch for surface sizing 0 1.58 1.26 DAK based on acid 16-methylheptadecanoic acid and stearic acid 0.5 1 2 4 1.67 1.76 1.85 1.86 1.19 1.22 1.31 1:32 Styrene-acrylate copolymer 1 2 4 1.58 1.60 1.67 1.23 1.25 1.25 Styrene-maleic anhydride copolymer 1 2 4 1.74 1.75 1.80 1.27 1.31 1.30

The results shown in Table 6 show that even better print quality was achieved with black and white printing than with the compounds commonly used in surface paper sizing.

T

Example 5

Surface sizing additives were also tested on a pilot plant paper machine. The paper types tested were sized without pre-surface sizing in a bath and film size press. The paper blend of fine paper had a basis weight of 80 g / m @ ² and contained 20% crystalline calcium carbonate (conventional “multipurpose” office paper) as a filler. An 8% solution of Raisamyl 405 SP (oxidized cationic surfactant, manufactured by Raisio Chemiclas Oy) was used as the surface sizing. Surface sizing starch was mixed with various surface sizing hydrophobising additives: basic DAK (60:40% palmitic acid / stearic acid), 16-methylheptadecanoic acid and stearic DAK (50:50% branched and unbranched acid ratio) , styrene-acrylate copolymer (Raisafob P400, manufactured by Raisio Chemicals Oy) and styrene-maleic anhydride copolymer (Raisafob D100, manufactured by Raisio Chemicals Oy).

The following Table 7 summarizes the results of the tests that were carried out on a pilot plant paper machine with a film size press.

Table 7 - Sizing results on a pilot mill paper machine with a film size press

Paper mixture + starch for surface sizing 0 42.3 143 0.25 25.6 255 Basic DAK 0.50 23.8 273 1 20.3 310 2 19.2 380 DAK based on acid 0.25 27.8 247 16 AKD 0.5 25.7 251 and stearic acid 1 22.3 239 2 20.4 285 Styrene-acrylate 2 30.8 223 copolymer 4 25.6 229 styrene 2 25.3 266 maleic anhydride copolymer 4 21.1 282

The following table 8 summarizes the results of inkjet printing (HP 560 C printer) on paper samples. The results were analyzed according to "dry" ·> evaluation methods.

Table 8 - Black and white print quality on the HP 560 P printer

Paper mixture + surface size 1.07 2.1 1 0.95 49057 1834 Basic DAK 0.5% 1.19 1.6 16 0.97 51103 2019 Basic DAK 1,0% 1.22 1.5 24 0.98 49152 1923 DAK based on 16- methylheptadecanoic acid and stearic acid 0.5% 1.18 1.6 7 0.97 48313 1913 DAK based on 16- methylheptadecanoic acid and stearic acid 1,0% 1.21 1.5 13 0.98 47609 1898 Styrene-acrylate copolymer 1.0%. 1.14 1.8 2 0.95 47654 1847 Styrene-acrylate copolymer 2.0% 1.14 1.7 4 0.96 47966 1821 styrene maleic anhydride copolymer 1,0% 1.20 1.6 17 0.96 47058 1808 styrene maleic anhydride copolymer 2.0% 1.23 1.5 26 0.97 47099 1909

The values given in Tables 7 and 8 show that the use of basic DAKs in the samples evaluated yields a very good degree of hydrophobicity. However, high hydrophobicity can lead to too slow color drying, which can lead to color imbalance in color layers in color printing. These values indicate that the best balance between sizing consumption, black and white and color print quality is achieved by using DAK based on 16-methylheptadecanoic and stearic acids containing branched and unbranched carbon chains.

Industrial use

The type of paper produced according to the present invention can be advantageously used for both black and color printing, since it does not present difficulties associated with inkjet printing. In particular, the paper produced according to the present invention has achieved an optimum balance between the absorption and hydrophobicity requirements of the paper. Therefore, both black and color inks can be printed with high quality. The benefits of multilayer printing include minimal transparency, high print density, elimination of bleeding and bleeding of colors, and minimal thickness of printed outlines. In addition, a balanced printing result is achieved by virtue of the nature of the paper prepared according to the invention without the need for sheet coating, surface treatment to improve hydrophobicity or the use of a higher than commonly used amount of starch for surface sizing. The type of paper produced according to the present invention therefore fulfills the requirements for office type paper for printers and can additionally serve as "multi-purpose" paper.

Using the size formulation of the present invention, it is possible to achieve the desired inkjet printing result with a lower dose of size than with conventional DAK-based sizing. This avoids the problems of fouling of the paper machine and the adhesion of dirt and fibers to the rollers caused by conventional DAK-based glues.

Claims (5)

PATENT CLAIMS A neutral or alkaline process for the production of an additive-containing paper type (in particular crystalline calcium carbonate as a filler), wherein a sheet of 2-oxethanone-size glue is added in the pulp phase to control the hydrophobicity of the paper, in inkjet printing, this is accomplished by the addition of a 2-oxethanone-based glue prepared from one or more fatty acids having a saturated backbone of 6 to 22 carbon atoms, of which at least one has a branched chain. A process as defined in claim 1, characterized in that 2-oxethanone-based sizing agent is prepared from the mixture of linear and branched fatty acids to the pulp. A process as defined in claim 2, characterized in that 2-oxethanone-based sizing agent is prepared from the fatty acid mixture to the pulp. The ratio of unbranched and branched fatty acids in this mixture is 1: 1. . , * A process as defined in claim 1, 2 or 3, characterized in that 2-oxethanone-based sizing agent is added to the slurry in an amount of 0.05 to 0.25% by weight of the fibers in the slurry. Method according to any one of the preceding claims 1 to 4, characterized in that in addition to the internal sizing of the paper, a surface sizing is also performed, which comprises a hydrophobizing sizing as defined in the meaning of claim 1. A type of paper, characterized in that any of the processes defined in claims 1 to 5 is used in its manufacture.