FR2524514A1 - IMPROVED COLOR COATED COMPOSITION FOR PAPER - Google Patents

Abstract

THE COATING COMPOSITION ACCORDING TO THE INVENTION INCLUDES AN AQUEOUS FILLER OR DISPERSION WHICH HAS BEEN TINTED WITH A WATER-SOLUBLE POLYCATIONIC DYE, COMBINED WITH A BINDING AGENT. APPLICATIONS: COLOR COATED PAPER PRODUCTION.

Description

It is common practice in paper making to use

  fillers that are usually white inorganic pigments These papers are frequently dyed, by

  example, with direct, acidic or basic dyes

  direct dyes are used predominantly to dye paper that is free of wood or has a low wood content, while basic dyes are suitable for dyeing wood-rich paper. It is desirable that dyestuff also be as much as possible on the paper fibers, for

  avoid subsequent exudation of color.

  The fillers can be added to the pellet from which the paper is made, but the high quality papers are often coated with a composition comprising an aqueous slurry of the filler with a binder, for example starch or synthetic resin, and optionally a dispersing agent For coated paper, another method of coloring the paper consists in applying to it a colored coating composition, generally containing one or more colored pigments either as a single filler or in conjunction with a white pigment. However, when using a mixture of white and colored pigments, these pigments frequently migrate to different degrees during the drying process, which can lead to non-uniform dyes In addition, the use of pigments is less effective than that of dyes

  soluble, especially for deep shades.

  It is known to add soluble dyes to

  water to coating compositions containing a white pigment.

  This presents a number of disadvantages, however, in

  especially for high quality paper This is due in part

  Due to the insufficient exhaustion of the dye on the substrate, resulting in insufficient strength properties. In a very general way, for any water-soluble dyes used in conjunction with white pigments, the difference in migration properties, particularly when A dye mixture is used which leads to non-uniform dyes and variations in depth. In addition, especially with basic dyes, the light fastness is poor; and the addition of cationic dyes to a stabilized coating system by

  anionic often causes precipitation.

  The Applicant has discovered according to the invention that these disadvantages can be overcome by coloring the filler with a water-soluble polycationic dye before incorporating it into the coating composition.

  especially good by the use of selected groups of

  cationic agents, as described below.

  The invention thus provides a colored coating composition for paper comprising an aqueous paste or dispersion of a filler which has been dyed by a polycationic dye.

  soluble in water together with a binding agent.

  Suitable fillers may be organic, for example urea / formaldehyde condensation products such as the commercial products "Pergopak" from Ciba-Geigy or "Lytron" from Monsanto, but they are preferably inorganic. white inorganic pigment Examples of fillers are finely divided silicates, for example kaolin (porcelain clay), talc (saponite), diatomite (kieselguhr or Foulon earth), French chalk, asbestine, calcium silicate (obtained in particular form). appropriate by mixing a cold concentrated solution of Ca C 12 with a cold concentrated solution of sodium silicate), quartz sand and asbestos sulfates, eg gypsum, annaline, lenzine, satin white (calcium sulfoaluminate), heavy spar and barite white (both BaSO 4); carbonates, eg calcium carbonate (eg lime), magnesite, whiterite, lead white, dolomite and calamine oxides or hydroxides, for example alumina, barite, titanium dioxide, slaked lime, calcined magnesia and zinc white; sulphides, for example lithopone and zinc sulphide; and sulfites, for example calcium sulphite. The preferred fillers for dyeing with cationic dyes are kaolin, calcium carbonate, talc, barite white, and titanium dioxide, especially kaolin, calcium carbonate, and the like. Talc It is surprising that even inexpensive fillers such as chalk give excellent results, especially with the chosen cationic dye groups.

24514.

  Polycationic dyes are understood to mean dyes having at least 1.3 cationic groups (quaternary or protonated nitrogen atom) per dye molecule, a non-integer value of the number of cationic groups to be understood as an average value for the molecules The dyestuffs in question may also contain anionic groups, in particular sulfonic acid groups, but if these groups are present, the

  number of cationic groups per molecule must be at least

  number of anionic groups per molecule If there are x cationic groups and y anionic groups per molecule, this is expressed algebraically by x> 1.3 and O <y <(x-1). The dyes

  preferred are bis-cationic dyes.

  The dyes may be metallized or metal-free, but metal dye complexes, preferably

  particularly metal-dye complexes 1: 1 and 1: 1.

  For 1: 2 complexes, containing two dye units per atom

  the condition of at least 1,3 cationic groups per

  This applies to each dye unit, not to each mole.

  As well as the azo dyes, one can use

  other cationic dyes, for example phthalate dyes

  cyanine (eg cupric phthalocyanine) and anthraquinone dyes. It is also possible to use dyes containing

  a group reactive with respect to the fibers.

  The dyes preferably have in the form of metal-free cations a molecular weight of at least 400, more preferably 500-1000.

  use, that is, they are exhausted from a solution -

  aqueous solution containing 1% dye, based on the weight of the filler, on the filler, at 20-90 ° C and without the use of dyeing auxiliaries, to a degree of at least 907. which give a high degree of exhaustion on the cotton, measured by the following test: the dye must give a ratio of exhaustion (ratio of the dye exhausted on the substrate to the total dye in the bath) from 90 to 1100%, defined in DIN 54000 or ISO RIOS / I 1959, part 1, in mercerised cotton stain at a standard depth of 1/1 from a boiling aqueous bath without electrolyte at a bath / article ratio 20: 1, dyeing time 90 min.

  The dyes fulfilling these conditions are mainly

  those having in their molecule peripheral or terminal cationic groups. A preferred dye group comprises phthalocyanine dyes containing two cationic groups.

  or more that are attached to the periphery of the phthalocyclic ring system

  planar cyanine Another preferred group of dyes has a substantially linear structure comprising at least 3 homo or heteroatomic fused ring or ring systems connected directly or by bridging groups such that there are two rings or terminal ring systems and at least one a core or median ring system, always with an average of at least 1.3 cationic groups per molecule attached to the ring or ring systems, and none elsewhere In a still preferred group, there are two or more, preferably two cationic groups per molecule, one or more, preferably one on each nucleus or

  terminal cyclical system and none elsewhere.

  Dyes having the properties and characteristics

  The above structural ticks are known in the art and described, for example, in the following published patents and patent applications: published patent applications of the Federal Republic of Germany 1,061,010, 1,064,661, 1,621,702, 2,250,676,

  2,251,041, 2,604,699, 2,627,680 and 2,810,246; US patents

  United States of America 3,709,903, 3,784,599, 3,839,426, 3,933,787, 3,935,182, 3,996,282, 4,046,502, 4,103,092, 4,146,558, 4,155,598 and 4,213,897; and published European patent applications 13,751, 14,677, 14,678,

  232, 233, 1511, 16,726, 24,321, 24,322, 34,725, 38,299,

  Nos. 616, 56,574, 62,824, 62,825, 63,261 and 65,595. Particularly preferred cationic dyes are those described in British Published Specification Nos. 2,076,421, 2,081,734, 2,082,615 A and 2,104,538. A, British Patent 2,019,873 and published European Patent Application No. 41,040, the contents of which are

  incorporated in this application for reference.

  The colored filler can be prepared by clumping the white pigment with water or by dispersing it in water using a nonionic and / or cationic dispersing agent, the solids content of the fart or the resulting dispersion being from 0.1 to 90% by weight, preferably from 10 to 70%. An aqueous 0.1 to 70% by weight solution, preferably a 5% solution, is then added to the stirred flask or dispersion. 40%, cationic dye at a temperature of 1-100 C, preferably 20-70 C The required dyeing time is 10 S to 60 min, a time of 1 to 20 min being generally sufficient.

classic fastening.

  The dry white pigment can also be vigorously mixed with the dry dye of powder or granulate and the resulting mixture mixed with water or dispersed in water using a dispersing agent. Dyeing conditions are

then the same as above.

  The resulting colored pigment can be isolated, for example by filtration, centrifugation or spray drying, and the product can be further washed and dried if necessary.

  use the colored suspension directly in the next step.

  In the preparation of the coating composition, it is desirable to add 0.1-10% of a dispersing agent,

  polyphosphate or polyacrylate Other dispersing agents

  Suitable solvents include the condensation products of aromatic compounds sulfonated with aldehydes, for example the condensation products of naphthalene, diphenyl, diphenyl ether and similar products sulfonated with formaldehyde. Dispersing agents

  preferred are the polycondensation products of P-naphthalene-

  sulfonic acid with formaldehyde, containing structural motifs

Na 03 CH 2 CH 2-

  m / C H 2 C 20; These dispersing agents, which are known, can also be used in combination with other dispersing agents, such as polyacrylates, especially when using large amounts of dyes, or where reach low

coating viscosities.

  The coating composition may contain any dispersions or emulsions of conventional aqueous binder agents, for example those based on starch, acrylates, butadiene / acrylonitrile,

  butadiene / styrene, polyvinyl chloride, poly-

  vinylidene, polyvinyl alcohol, polyvinyl acetate and their copolymers and mixtures, as described for example in the published patent application of the Federal Republic of Germany

No. 2,938,896.

  If clear shades of color are required, the colored filler can be mixed in suitable proportions with an undyed white pigment. The colored coating compositions can be applied to paper, which can itself be white or colored, by Any conventional coating method used in the paper industry The colored coated paper according to the invention has good lightfastness and excellent resistance to abrasion.

  exudation, for example by water, alcohol, milk or soap.

  Due to the high affinity of these dyes for the charge, there is virtually no differential migration effects upon drying and even colorations are obtained even when using

combinations of dyes.

  Staining is performed with high efficiency

  and a minimum of contamination of the equipment and water

  If a cationic dye is added to a coating composition which has not been fully depleted on the filler, or if the composition contains a filler which has been dyed with an insufficiently substantive cationic dye, the dye which is in solution

  can cause agglomeration and thickening of the composition.

  The rheological properties of the composition can be sufficiently altered so that it is no longer possible to apply it by coating and the stability of the composition can be severely reduced. The present invention makes it possible to overcome this disadvantage, by giving an excellent stability of the composition. sleeping composition, as well as

  good strength properties of colored paper.

  The colored paper by the process of the invention can be bleached without difficulty, unlike coated paper with compositions containing coloring pigments. This is of considerable importance for the recycling of colored and coated paper waste. The colored paper according to the invention accepts very well the printing and it is exceptionally suitable as paper of

xerographic copy.

  The following examples illustrate the invention without, however, limiting its scope. In these examples, the parts and

  percentages are all by weight.

Example 1

  285.7 parts of a 35% aqueous dispersion of kaolin (from English China Clay Ltd) containing 100 parts of kaolin in dry weight are stirred at room temperature (20 ° C.) and parts of a solution are added. 25% aqueous dye of formula 1Cu Pc 4-4 CE 2 N And 3 Ci) 3 in which Pc denotes the rest of the phthalocyanine and Et represents the ethyl group After a dyeing time of 2 min, 1.5 is added part of a dispersing agent based on sodium polyacrylate, sold by the company BASF under the name "Polysalz F", then 20 parts of a synthetic binder with 507 butadiene / styrene-based solids, sold under the name "Dow 620" by the Dow Company The pH is adjusted to 8.5 by ammonia at 25%. A deep turquoise-blue coating composition having a solids content is obtained.

about 40%.

  This composition is applied to a non-layer paper weighing 80 g / m 2 by means of a doctor blade at an application rate of 20 g of dry substance per m. Finally, the paper is dried in

  a convection dryer at 105 ° C for 60 s.

  A layer paper, uniformly and deeply colored, having excellent water and alcohol fastness is obtained.

  wet, as well as good light fastness.

Example 2

  Example 1 is repeated, but using as dye parts of a 20% aqueous solution of the dye of formula O-C N 4 (223 m (CH 2 Cl 2)

N N X Q

Sg O NH (CH 2) 3 NH (CH 3) 2

Example 3

  100 parts of chalk ("Omyalite 90") are impregnated with parts of water and homogenized in a Roth disperser until a stable viscosity is obtained (approximately 10 min). Then, parts of dye presented in example 2, After stirring for 5 minutes, 1 part of dispersing agent ("Polysalz F") is added and, after another 2 minutes, the

colorful suspension.

  The filter residue remains dyed deep blue and the filtrate is virtually colorless, even after repeated washing by

  Water The product can be used as described in Example 1.

  It is to be understood that the invention is not limited to the preferred embodiments described above by way of illustration and that those skilled in the art may make modifications without

depart from the scope of the invention.

Claims (13)

R E V E N D I C A T IO N S   A colored coating composition for paper, characterized in that it comprises an aqueous mate or dispersion of a filler which has been dyed by a water-soluble polycationic dye together with a binder. Coating composition according to Claim 1, characterized in that the filler is kaolin, carbonate of calcium or talc.   Coating composition according to claim 1 or 2,   characterized in that the dye is a bis-cationic dye.   4 coating composition according to any one of   preceding claims, characterized in that the dye is   a metal dye complex.   Coating composition according to claim 4, characterized in that the dye is a metal complex of azoic dye 1: 1 or 1: 2.   6 Sleeping composition according to any one of   preceding claims, characterized in that the dye, at   the metal-free cation state has a molecular weight of at least 400.   Sleeping composition according to any one of   preceding claims, characterized in that the colorant   is depleted on the feedstock from an aqueous solution containing 17.   dye, based on the weight of the filler, at 20-90 ° C and without   the use of dyeing auxiliaries, to a degree of at least 90%.   Coating composition according to any one of   preceding claims, characterized in that the dye   a depletion rate (ratio of the dye used on the substrate to the total dye in the bath) of 90-100 X, defined by DIN 54 000 or ISO RIOS / I 1959, part 1, in the dyeing of mercerized cotton with a standard depth of 1/1 from an aqueous bath boiling without electrolyte at a liquor / article ratio of: 1, for a dyeing time of 90 min. 9 coating composition according to any one of   of the preceding claims, characterized in that the colorant   is a phthalocyanine dye containing 2 or more cationic groups which are attached to the periphery of the phthalocyanine ring system. Coating composition according to any one of   Claims 1 to 8, characterized in that the dye has a   substantially linear structure comprising three cores or systems   cyclic condensed homo or heteroaromatic or more directly connected   or by bridging groups such that there are two rings or ring systems and at least one ring or median ring system, with an average of at least 1.3 cationic groups per molecule attached to the rings or ring systems terminals, and no where else.   Coating composition according to claim 10, characterized in that the dye has a cationic group on   each kernel or terminal cyclic system and none elsewhere.   12 Coating composition according to any one of   preceding claims, characterized in that it contains   0.1-10% by weight of a dispersing agent.   Coating composition according to claim 12,   characterized in that the dispersing agent is a condensation product   of p-naphthalenesulfonic acid with formaldehyde, containing structural units CH 2   Na O 3 S SO 3 Na 14 Dyed charge, characterized in that it is selected from kaolin, calcium carbonate, talc, barite white   and titanium dioxide and is dyed with a poly- cationic.   Dyed filler according to Claim 14, characterized in that it consists of chalk dyed with a dye of formula Cu O C Q 23,322 3 (CH 2) 3 (CH 3) 2 2   in the form of a 20% aqueous solution in the presence of an agent   dispersant based on sodium polyacrylate.   Process for the production of colored coated paper, characterized in that a composition of   coating according to any one of claims 1 to 13.   17 Colored coated paper, characterized in that it is lying   with a coating composition according to any one of the 1 to 13.