DE1260291B - Paper coating slip containing elastomers - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

Number:
File number:
Registration date:
Display day:

D21h

German class: 55 f- 15/20

O 10108 VI b / 55 f
April 25, 1964
1st February 1968

The invention relates to coating slips which contain elastomers in latex form as binders and to themselves particularly suitable for coating paper.

The use of coating slips to improve appearance, water resistance, strength and printability as well as to produce other desirable properties in paper, paperboard and the like has long been known. The coating slips used for this consisted essentially of one suitable pigment, such as. B. clay calcium carbonate, titanium dioxide and the like, and a binder or adhesive in aqueous dispersion. Starch and protein have been used extensively as binders or adhesives. It has also been known for a long time to use such coating slips either instead of or together with Add starch or protein adhesives, elastomers or resins in latex form.

The use of elastomers or resins in latex form as adhesives in paints for However, paper has not been entirely satisfactory, particularly in terms of wet abrasion resistance Coating.

To overcome the previous disadvantages of using such latexes in coatings and to further improve the properties of these coating slips, the use of a Latex from an elastomer or resin with one or more functional groups in the polymer structure suggested. Such latex types are well known and readily available in the industry brought significant advantages through their use in paper coating. As well as others Latex types for paper coating led the latex types with functional groups to coatings with insufficient water resistance.

Elastomers or resins with functional groups include, inter alia, copolymer, terpolymer or multipolymer emulsion systems, as they are variously used as adhesives, pigment binders or film formers are described, understood. These substances contain one or more comonomers, the reactive vinyl group necessary for the formation of the polymer latex and one more or more functional groups, such as. B. Carboxyl groups and organic hydroxyl groups, wear, or combinations of comonomers with the same groups, with or without additional, functional amino or amido groups carrying comonomers. These reactive comonomers can be those with carboxyl groups, such as. B. acrylic acid, methacrylic acid, maleic acid or maleic anhydride and itaconic acid, or paper coating slip containing those containing hydroxyl elastomers

Applicant:
5

Oxford Paper Company,

New York, N.Y. (V. St. A.)

Representative:

Dr.-Ing. E. Maier, patent attorney,
7000 Stuttgart 1, Werastr. 24

Named as inventor:
Robert Thompson Hart,
Rumford, Me. (V. St. A.)

Claimed priority:

V. St. v. America May 16, 1963 (281030) - -

groups, like ζ. B. hydroxyethyl methacrylate, hydroxypropyl methacrylate and N-methylol acrylamide.

It is already known that certain water-soluble adhesives, such as. B. starch and egg white, can be made water-insoluble by adding ammonium zirconyl carbonate.
The present invention is based on the knowledge that coating slips which contain elastomers having functional groups as binders in latex form and small amounts of ammonium zirconyl carbonate are insoluble in water.

The exact effect of ammonium zirconyl carbonate in terms of changing durability and the water resistance of the coating slip according to the invention cannot be matched Determine security. Obviously, this is not a matter of making the copolymer insoluble, rather an increase in the adhesion or cohesion of the binder, perhaps both and possibly some crosslinking of the copolymers.

The paper coating slips according to the invention are of particular advantage when the in Elastomer present in latex form is a functional group-containing styrene-butadiene copolymer is. The best results are achieved when the functional groups are carboxyl groups are. A styrene-butadiene copolymer containing carboxyl groups is in latex form from the

709 747/511

Koppers Company, Inc., and sold under the trade name "Dylex K-55". The product has the following composition:

Solids content 48 ± 1 ° / o

Ratio of carboxyl-containing styrene and butadiene im

Copolymer 60:40

Viscosity of the latex at 25 ^° C. .... 40 to 50 cP

pH at 25 ^° C. 9.5 ± 0.5

Specific gravity 1.015

Weight per liter about 1 kg

Favorable results are also obtained when using a very similar one containing carboxyl groups Styrene-butadiene-based copolymer latex available from The Borden Chemical Company under is sold under the trade name »Polyco 0415« and has the following properties:

Solids content 48 ± 0.5%

Ratio of carboxyl-containing styrene and butadiene in the copolymer .. 60:40

Viscosity (max.) 5OcP

pH at 25 ° C 9 to 10

Particle size 0.1 to 0.3 microns

Weight per liter about 1 kg

Another cheap to use, carboxylated styrene-butadiene copolymer latex is from The Dow Chemical Comp, manufactured and sold under the trade name "QX 3367.1". The product has the following characteristics:

Solids content 48.0 ° / ₀

'pH 9.0

Specific gravity of the latex 1.001

Specific gravity of the solids .. 1.002

Weight of latex per liter about 1 kg

Surface tension 40.00

Emulsion of an acrylic terpolymer containing carboxyl groups expelled. The product has the following properties:

Solids content 45 ± 0.5 ° / ₀

Ionization non-ionized emulsion

pH 5.5 to 6.5

Particle size less than 1.0 micron

Yet another functional group elastomer latex to be used with advantage is one of The Goodyear Tire and Rubber Company and sold under the trade name "Pliolite Latex 460" Carboxyl group-containing styrene-butadiene copolymer latex with the following properties:

Total solids 52%

pH 8.5

Viscosity 200 cP

Surface tension 32 dynes / cm

Specific gravity of latex solids 1.02

a ₅ Average particle size 2500 Ä

Solids content 1.95 kg / 1.951

Latex lkg / 1

In addition, the following copolymeric elastomer latices can advantageously be used in the process according to the invention can be used with functional groups:

One manufactured by Union Carbide Chemicals Comp, and under the tradename Acrylic latex sold "UCAR-40". One manufactured by Union Carbide Chemicals Comp, and under the trade name "UCAR-110" marketed styrene-butadiene copolymer with functional Groups. A manufactured by Röhm and Haas and sold under the trade name »Rhoplex B-15« sold acrylic polymer latex with functional groups, pH 6.5, and a solids content of 46%.

Excellent results have been obtained using a similar copolymeric elastomer latex with functional groups based on styrene-butadiene, also from The Dow Chemical Comp, manufactured and sold under the trade name "Dow-Latex 636". The product has the following properties:

Solids content 48%

pH 9.5

Specific weight of the latex

at 25 ° C 1.003

Specific weight of the solids

at 25 ° C 1.008

Weight per liter about 1 kg

Viscosity 40 cP

Another elastomer latex with functional groups, which can be used favorably in the process according to the invention, is manufactured by Crown Chemical Corporation and under the trade name "Acrylic Emulsion MC-100" in the form of an aqueous solution. All that is needed is ammonium zirconyl carbonate to be dispersed in the coating slip present in the form of an aqueous dispersion and to allow the coating slip to dry at room temperature after application. The resulting coating does not need to be heated for satisfactory curing of the copolymer ^{, but heating at about 95 °} C. for 1 to 3 minutes causes accelerated curing.

The invention is particularly suitable for those elastomers or resins which are not heat-curable at the working temperatures customary in the paper industry.
The amount of ammonium zirconyl carbonate to be added to the coating slip can vary within wide limits and is advantageously between about 0.5 and about 20%, based on the weight of the latex solids. The particular amount to be used depends on the results desired and the types of latex and other adhesives present in the coating slip.

If only air drying is being considered, a larger amount of ammonium zirconyl carbonate should be used

can be used than when drying at elevated temperature.

With a clear advantage was for this purpose commercial Ammoniumzirkonylkarbonat with 10 ° / ₀ · solids based on zirconium dioxide ZrO ₂ content is used. To carry out the process according to the invention, however, preference is given to an ammonium zirconyl carbonate solution which is prepared by reacting zirconium oxychloride with a theoretical amount of an aqueous ammonium carbonate solution containing a small amount of ammonia, ie about 1 percent by weight of the ammonium carbonate. This reaction can be easily carried out by pouring the Zirkonoxychlorids immersed in a 20 to 3O ° / _O, a small amount of added 28% aqueous ammonia containing ammonium carbonate, wherein the reaction starts at room temperature immediately. The resulting solution contains 5.75 ° / ₀ solids, based on the Zirkondioxydgehalt. In addition to the ammonium zirconyl carbonate, the reaction produces ammonium chloride, which remains in the ammonium zirconyl carbonate solution and appears to catalyze the effect of the ammonium zirconyl carbonate on the elastomers.

Instead of zirconium oxychloride, other soluble zirconium salts, e.g. B. zirconium sulfate is used will; however, excellent results are obtained when using zirconium oxychloride, especially with regard to the presence of ammonium chloride in the solution obtained.

Instead of producing the ammonium chloride in the production of ammonium zirconyl carbonate, can it is also added subsequently to a commercially available ammonium zirconyl carbonate solution, if desired or are added separately in catalytic amounts to the coating slip.

The advantageous application of the method according to the invention is illustrated by the following examples Explained latex of the type described as a solid adhesive containing paper coating slips. With these In a series of tests, the quality of the individual coatings was determined by the customary wet abrasion test.

Unless otherwise stated, the amounts given are amounts by weight.

example 1

A coating composition was prepared in the form of an aqueous dispersion of 60 ° / ₀ solids and contained 100 parts of dry clay and the "K-55 as described above," latex in a 15 parts, based on

ό the dry weight of the copolymer, appropriate Lot. A portion (A) was taken from this coating slip as a comparison sample. A second, severed one Portion (B) of the same coating mass was 10 percent by weight of a commercially available, 1.5 parts of ammonium zirconyl carbonate solution containing ammonium zirconyl carbonate (AZC) were added. A further portion (C) of the coating slip (A) was given 20 parts by weight of one as described above ammonium zirconyl carbonate solution produced

ao given. This contained a small AZC equivalent to about 1.15 parts dry weight Amount of ammonium chloride.

A further portion (D) of the coating slip (A) was a urea-formaldehyde resin in one

The ratio of 3 parts resin to 15 parts latex solids was added. One portion (E) of the coating slip (A) was added to 15 parts of the "K-55" latex solids an amount of the ammonium zirconyl carbonate prepared as described above corresponding to about 0.86 part of AZC and about 1 to ¹ I ₂ parts of urea-formaldehyde Resin added.

Each of the coating slips produced in this way was on

sized base paper in an amount of about 4.5 kg / ream (25 "x 38" / 50O) based on the dry weight, applied and dried in the air at room temperature without external heat supply. With Paper coated in a similar manner to the corresponding coating slips was for 1, 2 and 3 minutes hardened in the oven at a temperature of about 95 ° C.

All samples were evaluated within 2 hours of coating; the results are given in the following table:

Table 1

Prank
Dimensions Solids
% viscosity
cP after drying
in the air
Room temperature Nassabriel
η
1 minute Devaluation
after drying at 95 ° ^C
2 minutes C.
3 minutes A. 60 136 bad bad bad sufficient B. 60 5616 outstanding outstanding outstanding outstanding C. 57.2 5368 outstanding outstanding outstanding outstanding D. 58.0 56 bad bad bad bad E. 57.3 2952 outstanding outstanding outstanding outstanding

Example 2 nelle groups of the "Polyco 0415" designated,

carboxylated styrene-butadiene latex was used

Another series of tests was carried out under the same 65 and that in the coating slip E only half of the in Conditions and using the same urine coatings used as the coating slip E of Example 1 carried out exactly as in Example 1, substance-formaldehyde resin amount was used. It where only instead of the latex »K-55« with function is a table with the evaluation of this test series:

Table 2

Prank
Dimensions Solids
% viscosity
cP after drying
in the air
Room temperature Wet abrasion rating
after drying at 95 ° ^C
1 minute I 2 minutes bad C.
3 minutes A. 65.1 9180 bad bad outstanding sufficient B. 55.5 8340 outstanding outstanding outstanding outstanding C. 55.0 10300 outstanding outstanding bad outstanding D. 59.5 806 bad bad outstanding bad E. 55.9 7040 outstanding outstanding outstanding

Example 3 groups of latex designated _{as "MC: 100"}

Another series of tests was applied under the same and in coating slip E the same Conditions and using the same amount of urea-formaldehyde resin as in coating slip carried out as in Example 1, except that 20 mass E of Example 2 was used. The following that instead of the latex "K-55" with a functional table, the evaluation of the test series contains:

Table 3 Prank
Dimensions Solids
% viscosity
cP after drying
in the air
Room temperature Wet abrasion rating
after drying at 95 ° C
1 minute | 2 minutes | 3 minutes sufficient A. 63.7 352 bad sufficient outstanding B. 62.2 2384 outstanding outstanding outstanding C. 61.4 1616 outstanding outstanding Well D. 63.2 372 bad sufficient outstanding E. 61.7 1464 outstanding outstanding

Example 4 Groups of those labeled "B-15" by Rohm and

Haas sold elastomer latex with functional

Another series of tests was used among the same groups and in coating slip B the Conditions and using the same same amount of urea-formaldehyde resin as in Coating slips carried out as in Example 1, except that 45 coating slip E from Example 2 was added, that instead of the latex "K-55" with functional table 4, the evaluation of the test series contains:

Table 4

Prank
Dimensions Solids
% viscosity
cP after drying
in the air
Room temperature Nassabriel
η
1 minute Devaluation
after drying at 95 '
2 minutes C.
3 minutes A. 65 148 bad sufficient sufficient Well B. 61 7520 outstanding outstanding outstanding outstanding C. 58.5 6912 outstanding outstanding outstanding outstanding D. 63.6 148 bad bad sufficient Well E. 61.2 5608 outstanding outstanding outstanding outstanding

B e i s ρ i e 1 5 65 that this time the elastomer called »QX 3367.1«

Another series of tests was carried out under the same merlatex from Dow Chemical Comp, which was used.

Conditions and using the same In Table 5 is the evaluation of this series of experiments

Coating slips carried out as in Example 1, except stated:

Table 5

10

Prank
Dimensions Solids
% viscosity
cP after drying
in the air
Room temperature Wet bread
η
1 minute valuation
after drying at 95 ° ^C
2 minutes C.
3 minutes A. 65.1 956 bad bad bad bad B. 59.9 7368 sufficient Well very good very good C. 54.8 9960 sufficient Well very good very good D. 63.5 752 bad bad bad bad E. 58.5 11900 sufficient Well Well very good

Example 6 * 5 coating slip carried out as in Example 1, except

that this time the elastomer called »Dow-636«

Another series of tests was carried out under the same latex that was used. In Table 6 is the evaluation conditions and given using the same direction of this test series:

Table 6

Prank
Dimensions Solids
% viscosity
cP after drying
in the air
Room temperature Wet abrasion rating
after drying
1 minute at 95 ° C
2 minutes A. 65.7 100 bad sufficient sufficient B. 59.0 3192 outstanding outstanding outstanding C. 55.5 3456 outstanding outstanding outstanding D. 63.3 124 bad sufficient sufficient E. 58.4 2988 outstanding outstanding outstanding

From the above results it can be seen that the layers made with the control samples without AZC had poor wet abrasion resistance unless they were cured by external heat. In contrast, most of the tests carried out according to the method according to the invention gave excellent results, even when drying was carried out at room temperature. The control samples had even after 3 minutes long curing at 95 ⁰ C, a significantly poorer wet abrasion resistance than the inventively prepared samples after air drying.

As already mentioned, the in the invention

The amount of AZC used in accordance with the method can be varied considerably. This is done through the the following examples:

Example 7

In this series of tests, a comparative sample identical to that used in Example 1 was prepared. The separated portions of this comparative sample was AZC in amounts of 1 to 10 ° / _0, based on the dry weight of the elastomer is added. Each of these coating slips was evaluated as in the previous examples. The results are given in the following table:

Table 7

Coating Solids
7o viscosity
cP after drying
in the air
Room temperature Naßab
1 minute friction rating
after drying
2 minutes mg at 95 ° C
3 minutes 4 minutes Comparative sample 65 188 S. S. S. A. A. + 1% AZC 65 296 S. A. A. A. G + 2% AZC 64.6 232 S. SG SG H H + 3% AZC 64.5 412 S. H H H H + 4% AZC 64.4 336 S. H H H H + 5 "/ ₀ AZC 64.2 530 G H H H H + 6% AZC 64.0 628 SG H H H H + 7 ° / ₀ AZC 63.9 1042 H H H H H + 10% AZC 63.5 2256 H H H H H A = sufficient. S = bad. ■ ...... - ^ ._ - - - ^ -. - -._- _r: -. 709 747/511

Claims (1)

11 12 claims: 2. coating mass according to claim 1, characterized 1. Paper coating slip, which elastomers are characterized in that the elastomer is a functional Contains latex form as a binder, thereby styrene-butadiene-co- containing nelle groups characterized in that it is small amounts of polymer. Contains ammonium zirconyl carbonate and that the 5 3rd coating mass according to claim 1 or 2, da- it contains elastomer functional groups characterized in that the functional groups having. pen are carboxyl groups. 709 747011 1.68 © Bundesdruckerei Berlin