DE1696168B2 - Method for gluing paper - Google Patents

Description

The present invention relates to a method using surface sizing of paper a new combination of certain known means for this purpose.

It is common knowledge to make paper in bulk using rosin and related products To glue fabrics ("resin glue") and aluminum salts.

From FR-PS 9 31 044 it is also known to improve the strength properties to impregnate finished paper with copolymers containing carboxyl groups. A gluing, so one an improvement in water and ink resistance associated with a certain degree of water repellency but not achieved here.

From BE-PS 6 54 889 sizing agents are known, which by reaction of a copolymer from a «-olefin and maleic anhydride with a diamine and subsequent crosslinking of the reaction product with an epihalohydrin. According to the teaching of the patent, only crosslinked copolymers can be used as sizing agents.

The US-PS 31 65 486 relates to copolymers of olefins and maleic anhydride with vinyl esters Ethylenically unsaturated carboxylic acids are crosslinked. Dispersions of the alkali, amine or Ammonium salts of the crosslinked copolymers are recommended for various purposes, e.g. B. as a thickener in printing pastes or door the treatment of the wastewater from paper mills, but not as surface sizing agents for paper.

The sizes achieved with the previously known agents are often insufficiently alkali-resistant and often applicable only with unsatisfactory results to high-filler papers. Object of the invention is to show a process for the surface sizing of paper, in which one is glued papers ίο contains, which have a high alkali resistance.

The object is achieved according to the invention in that Al ^{+ + +} - or Fe ^{+ + +} cations contain "^ - paper on the surface with water-soluble Sab> of copolymers made from

(A) vinyl alkyl ethers and / or vinyl cyclohexyl ethers and

(b) maleic anhydride and / or maleic acid monoalkyl esters

are constructed as characteristic comonomers, is impregnated.

Aluminum sulphate ("alum"), aluminum acetate, basic aluminum chloride, basic aluminum acetate and iron (III) chloride are particularly suitable for stirring in the Al ^{+ + +} or Fe ^{+ + + cations.} The aluminum salts are recommended for white paper, while the iron III) salts can be used for papers in which a brownish-yellow tinge does not interfere, in both cases about 0.005 to 0.5, preferably 0.02 to 0.1 percent by weight of the cations, based on the amount of fiber. The salts are expediently added to the paper pulp; but you can also impregnate the finished paper with a solution of the salts before treating it with the copolymer.

The vinyl alkyl ethers (a) used to build up the copolymers should preferably be 3 to 12, in particular Contain 5 to 8 carbon atoms. The vinyl alkyl ethers with branched

th Cj- to C _e -alkyl radicals proved. The proportion of this

Comonomers should be about 50 to 70, preferably 50 to 60, mol percent, based on the amount of the copolymer.

For the preparation of the copolymers by

customary radical copolymerization for the

takes place moderately in organic solution or dispersion, maleic anhydride is preferred and then hydrolyzes the polymer. The amido or alkyl groups are then through subsequent amidation or esterification introduced into the copolymer, unless the maleic acid monoalkyl ester used as starting monomers (b). The alkyl groups in the last-mentioned compounds should preferably have 1 to 4 carbon atoms contain; this also applies to the alcohols with which the copolymers are subsequently esterified. The decisive factor for the average degree of amidation or esterification is that the salts of the carboxyl group-containing Copolymer remain soluble in water. The mean degree of amidation or esterification can therefore generally be up to 70% of all available carboxyl groups.

As copolymers, those from about 50 to 60 mol percent vinyl butyl ether and 40 bis have proven to be useful 50 mole percent maleic anhydride is particularly good.

In addition to the comonomers (a) and (b), the

Copolymers up to about 20 mol percent of other polymerizable compounds (c)

^ u ^^^ ViU:

be constructed, including.:. B. from acrylic acid, methacrylic acid, Acrylonitrile, methacrylonitrile, acrylamide. Methacrylamide, the Ci- to Q-alkyl esters of acrylic acid and methacrylic acid, the vinyl esters of C 1 -C 4 alkyl carboxylic acids, vinyl chloride and styrene.

For the preparation of the water-soluble salts of the copolymers which have free carboxyl groups or Contain anhydride groups, not all of the carboxyl groups need to be neutralized, but is sufficient a degree of neutralization of 60%, based on the number of all carboxyl or anhydride groups, im general already out.

The main cations are ammonium or mono-, di- or trialkylammonium with a total of up to 6 carbon atoms as well as further z. B. Sodium. These cations are introduced into the as usual Copolymers. i.e. through reaction with, among other things, ammonia and the free organic amines or caustic soda or sodium carbonate. ■

The required amount of the copolymers is between 0.05 and 5, preferably 0.1 and 2 percent by weight, based on the amount of fiber. The weight ratio of the amount of copolymer to the amount of ΑΓ ⁺⁺ or Fe ⁺⁺⁺ cations should preferably be between about 1:10 and 1: 300.

In addition to the salt copolymer combination to be used according to the invention for sizing, also other nonionic or anionic sizing agents, e.g. B. resin glue can also be used. Quite in general, the new agents with paper auxiliaries such as fillers, pigments, dyes, wet strength agents, Brighteners and other agents well tolerated. This applies to the manufacture of glued Papers of all strengths and types, e.g. B. for paper and cardboard made of bleached and unbleached Sulphite or sulphate pulp and wood pulp.

The method of gluing with the new means is otherwise similar to the conventional procedures the surface sizing, so that there is no need for further explanations.

According to the object of the invention, papers with excellent sizing effects are obtained, The alkali resistance and the good filler compatibility are particularly emphasized.

Unless otherwise stated, the percentages below relate to the weight.

example 1

An approximately 0.5% pulp suspension of 100% bleached sulfite pulp, which contains 0.5% (based on the amount of fiber) aluminum sulfate, is processed in the usual way to give paper with a basis weight of 80 gm ² .

This paper is then treated with a 2.4% strength aqueous solution of the ammonium salt (degree of salinity 100%) of a copolymer of 50 mol percent vinyl isobutyl ether and 50 mol% maleic anhydride to 1.2% solid absorption (based on the Amount of paper) impregnated and then dried.

In comparison, the same paper was glued as usual with resin glue in the mass, since one after this method achieves the next comparable sizing effects.

The degree of sizing was then determined according to the Cobb test (DIN standard 53/32 I min) and after the ink swim niprobc (test ink according to DIN 53I26) certainly. The results are shown in the following overview:

paper

Cobb test
after I minute

Tin swim test

According to the invention 20
glued

Conventionally 50
glues (mass)

Not very good

140

no breakdown after 5 min

Breakthrough after 3 min

Breakdown after 1 min

Example 2

A fiber suspension of freeness 38 = SR made of 30% wood pulp and 70% bleached cellulose, which contains additives (based on the amount of fiber) of 14% kaolin and 1% aluminum sulfate, is made into paper in the usual way (80g m ² ) and treats it further with the sizing agents mentioned in Example 1.

The quality of the glue is illustrated by the following values:

paper

Cohh test Tinlensehwimmprobe

1 min 5 min

According to the invention 17
seleimt

Breakdown after 10 min

Conventional
glued (mass)

Not very good

45 60 breakthrough after 6 min

120 130 breakthrough after 1 min

Example 3

A fiber suspension made of bleached sulphite pulp (= 100%), 12% kaolin and 3% aluminum sulphate is processed as usual into paper ^{with a basis weight of 80 g / m 2} and it is then impregnated with an aqueous solution containing 1.5% of the ammonium salt (degree of salinity 90%) of a copolymer of 50 mol percent vinyl butyl ether and 50 mol percent maleic anhydride and 2% hot-water-soluble oxidatively degraded starch, to about 1.5% solids absorption.

In comparison to this, a paper usually sized in the mass with resin glue is produced.

The test of the degree of sizing resulted in the following Values:

paper
60 (.'ohb test
I minute Tinlensehwimmprobe lirlindungsgcgc
glued IS Breakthrough
after 12 min Conventional
⁶⁵ glued (mass) 60 Breakthrough
after 6 min Unsized 110 Breakthrough
after 2 min

Example 4

A fiber suspension of bleached sulphite oil (= 100%), 12% kaolin, 3% aluminum sulphate and 1% of a commercially available anionic urea-formaldehyde wet-strength resin is processed in the usual way to paper with a basis weight of 80 g / m ² . The paper is then impregnated with an aqueous solution of the methylammonium salt (degree of salinity 100%) of a copolymer of 55 mol percent vinylcyclohexyl ether and 45 mol percent maleic anhydride, which also contained 0.02% of a commercially available anionic optical brightener. The solids uptake was 1.8% and in a parallel experiment 0.9%.

In comparison, the paper was sized as usual with resin glue. The exam after the Cobb test and for alkali resistance, in which the time was measured that a drop of 10% sodium hydroxide solution needed to move into the paper yielded the following values:

paper Cobb test
5 minutes Alkali Liquor Kit
IMinulenl According to the invention
glued, 1.8% 16 120 According to the invention
glued, 0.9% 25th 80 Conventional
glued (mass) 45 15th Unsized 112 <5 Example 5

Alkylrcsl in Vinyläthcr

Ink Cobb Resistance Test
(after
5 min)

C (CH ₃ )., Good 32

-CH ₂ -CH (CHj) ₂ very good 28

(CH ₂ ) ₄ -CH (CH,) ₂ good 36

-CH ₂ -CH (C ₂ Hs) - (CH ₂ )., -CH, good 42

Example 6

A fiber suspension made of bleached sulfite pulp (= 100%) is processed. 1% aluminum sulphate and 0.5% sodium aluminate as usual for paper with a basis weight of 80 g / m ² and then subjects this to surface sizing to 1.0% solids uptake with a 0.5% aqueous solution of the ammonium salt (degree of salinity 100%) ) a copolymer of 50 mol percent of maleic acid monobutyl ester and 50 mol percent of methyl vinyl ether or 50 mol percent of ethyl vinyl ether.

The results are shown in the following overview:

Alk'.lresi in the VinUether

-CH ₃
-C ₂ H ₅

35

40

A fiber suspension of bleached sulfite pulp (= 100%) and 2% aluminum sulfate is processed in the usual way to paper with a basis weight of 80 g / m ² and this paper is then subjected to surface sizing to 0.8% solids uptake with a 0.5% aqueous solution Solution of the ammonium salt (degree of salinity 100%) of a copolymer of 50 mol percent maleic anhydride and 50 mol percent of a vinyl alkyl ether, which is indicated in the following table:

55

60

Tin strength Cohb-TeM
(5 minutes) very good 40 very good 35

Example 7

A fiber suspension made of bleached sulfite pulp (= 100%) and 3% aluminum sulfate is processed as usual into paper of the basis weight 80 g nr and then glues it on the surface to 1.4% solids absorption with a 0.5% aqueous solution of the ammonium salt (degree of salinity 100%) of a copolymer of 52 mol percent Vinyl butyl ether and 48 mole percent of the maleic acid monobutyl ester. The sizing turned out to be excellent inkproof; the value for the Cobb test (5 min) was about 30.

Example 8

A fiber suspension of 30% wood pulp and 70% bleached cellulose, which contains 15% kaolin and 3% aluminum sulfate, is processed, as usual, into paper with a basis weight of 80 g / m ² . This paper is then superficially sized to 1.2% solids uptake with an aqueous solution containing 2% hot-water-soluble starch and 0.5% of the ammonium salt (degree of salinity 100%) of a copolymer of 50 mole percent vinyl isobutyl ether and 50 mole percent maleic anhydride, the anhydride groups of which according to the Polymerization with ammonia were converted into monoamide groups.

The ink floating time of the paper sized in this way was about 10 minutes, the time after the Cobb test were 17 (1 min) and 26 (5 min).

Example 9

A pulp suspension of bleached sulfite pulp (= 100%) and 2% iron (IIl) chloride is processed as usual into paper with a basis weight of 80 g / m ² and the surface is then glued to 0.8% solids absorption with a 2% aqueous solution of the ammonium salt (degree of salinity 100%) of a copolymer of 55 mol percent vinyl isobutyl ether and 45 mol percent maleic anhydride. The yellow-brown paper thus sized had good ink fastness.

Claims (6)

Patent claims: 1. A method for sizing paper, characterized in thatAl ^{+ + +} - or Fe ^{++ +} cations-containing paper on the surface with water-soluble salts of copolymers made from (A) vinyl alkyl ethers and / or vinyl cyclohexyl ethers and (b) maleic anhydride and / or maleic acid monoalkyl esters are constructed as characteristic comonomers, is impregnated. 2. The method according to claim 1, characterized in that partially esterified or amidierle Copolymers are used. 3. The method according to claim 1, characterized in that copolymers with 50 to 70 mole percent (a) and 30 to 50 mole percent (b) can be used. 4. Process according to claims 1 to 3, characterized in that copolymers, the additionally contain up to 20 mol percent of further monomers (c), can be used. 5. Process according to claims 1 to 4, characterized in that as water-soluble Salts of the copolymers ammonium or sodium salts can be used. 6. Process according to claims 1 to 4, characterized in that 0.005 to 0.5 percent by weight of Al ^{++ +} - or Fe ^{+ + +} cations and 0.05 to 5 percent by weight of copolymer salts, based on the amount of Pulp, can be used.