NL7908749A - AGENT AGAINST SENSITIVITY OF INK. - Google Patents

Description

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Remedy for the sensitivity of starch to ink.

The invention relates to an agent against the sensitivity of starch to ink, in particular flexographic ink, such as is used in the manufacture of corrugated board and which enters the starch by using water which for cleaning is prepared for its preparation. of the printing machines has been used.

By "agent" is meant a method of preparing the adhesive, an additive for smelling therein, and the preparation of the adhesive is used and to which such an additive has been added.

Starch lijra is usually prepared in three different ways. According to the Stein-Hall process, an aqueous suspension of gelatinized starch is mixed with starch milk, the gelatinized starch serving as "carrier" for the starch granules in the milk. According to a second method, a starch milk is used, the granules of which are partially gelatinized, which makes the use of a carrier unnecessary. According to a third method, an aqueous dispersion of granular starch, a base and a product which is at least partially soluble in cold water is used, for example a starchy product, carboxymethyl cellulose or polyvinyl alcohol.

Corrugated board is usually printed flexographically using an ink of a complex composition in which the colorant, the solvent and the surfactant are the major ingredients.

When the pressure equipment has been cleaned with water, the wash water contains flexographic ink, which means that it cannot be removed without a problem due to environmental pollution.

Purification requires extremely large equipment in 7908749 t

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2 related to the volume and concentration of the wash water (concentration on the order of 1-3%). However, even if a corrugated board factory has a purifier, it is usually inadequate because one flexographic ink is very different from another so that it is impossible to foresee how the wash water will behave in the purifier.

It has been proposed to use the flexographic ink-containing wash water for the preparation of starch adhesive for corrugated manufacturing, but it has been found that certain inks are incompatible with starch or that starch does not tolerate certain inks, so that at least some inks adversely affect the gelatinization point and the viscosity of the starch.

To illustrate these difficulties, the results of tests with an adhesive to which various types of flexographic ink have been added are set forth below.

The adhesive was of a kind used for manufacturing corrugated board which is provided with a web of thin board on both sides of the corrugated sheet. The starch was prepared according to the Stein-20 Hall process by preparing a "carrier" by partial gelatinization of starch with lye and addition of water, untreated starch and borax. To this end, a mixture of 450 l of water and 50 kg of corn starch was made at 45 ° c heated after which 9 kg of lye were added sufficient to gelatinize the starch After stirring for 15 min, 25 were added successively 700 l of water, 250 kg of starch and 6 kg of borax After stirring for another 15 min, 35 kg of an A indicated flexographic ink, which amount corresponds to 5% water in the starch milk The ink was previously adjusted to a viscosity of 20 seconds with a Ford cup No. 4.

The ink-containing adhesive was coated with the

Lory viscosity (outflow time) determined with a device from Braive Instruments, Liège, Belgium, the Brookfield (shear) viscosity with a RVF type viscometer from Brookfield, Massachusetts, USA America and the gelatinization point 35 with a Brabender viscosigraph from Brabender, OHG, Duisburg.

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In determining the gelatinization point, the mixture is heated in the bowl of the viscose and the temperature at which the untreated starch gelatinizes in the starch milk is measured, which is evidenced by a sharp increase in viscosity. The results 5 are summarized in Table A below.

TABLE · A

Viscosity Lory visco- Brookfield Gelatin van lory sity & 4 viscosity point (sec.) Hours standing, cp (° c) 10 (sec.)

Blank (without ink) 19 21 280 50

Blue 18 18 275 55

Yellow 18 24 310 54 yg Blue 15.5 16 250 54

Green 15 16 240 54

Chromate yellow "1" 39 21 780 59

Chromate yellow "3" not measurable 19 29,000 58

Black 15 16 230 52 20 Red 43 27 2,200 56

Orange, 17 19.5 350 53.5

Blue 20.5 10.5 400 54

Yellow 15 15 230 53.5 The results show that the gelatinization point is significantly increased by the ink, and that some inks also have an unfavorable influence on the viscosity. With regard to the latter, it must be taken into account that the washing water from cleaning the printing machines contains mixtures of different inks and that in practice there is always one which has an adverse effect on viscosity. The use of wash water containing flexographic ink for the preparation of starch glue for corrugated board has therefore practically been abandoned.

It has further been proposed to use the wash water to prepare starch glue for corrugated board, but to remove the harmful ink components by flocculating and removing, for example, by filtering, then 0 0 7 Λ a g V ^ V 3 t v 4. However, such treatment is complicated and requires extensive equipment so that it is not eligible for practical application.

According to the invention, there is provided a means of preparing starch glue using washing water-derived printing machines for flexographic printing of corrugated board without the ink present in the washing water adversely affecting the gelatinization point and the viscosity of the glue.

The agent according to the invention consists of a 3+ salt or oxide of Ca, Mg, Mn, Ni, Ba, Co, Cr, Al, Fe, Zn, Sr, Pb,

Sn, Ti, V, Cu, Mo, Cd, Sb, W, Bi, as well as silicone aluminates, activated carbon, cement and silicates.

Preferably salts and oxides of 3+ are used

Ca, Mg, Mn, Ni, Co, Cr, Fe, as well as silicoaluminates, activated carbon and cement, and in particular a silicate.

The invention therefore relates to a method for preparing an adhesive for corrugated board using washing water from flexographic printing machines, characterized in that, on a raw material for the adhesive, in particular starch, on a washing water, a suspension of gelatinized starch ("carrier") or of starch milk (ungelatinized starch) with which the gelatinized starch slurry is mixed before adding the wash water and adding at least one of the aforementioned agents at the usual pH for preparing corrugated board adhesive and if necessarily a base, all in quantities chosen such that the ink in the detergent does not adversely affect the properties of the adhesive.

The invention further relates to an additive for the preparation of corrugated cardboard adhesive using washing water from flexographic printing machines, characterized in that the addition is selected from one of the aforementioned agents and at pH used for preparing corrugated cardboard adhesive. is added to the washing water, as a raw material for golf.- jö o ά 9, · f · »* * **,

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-5 cardboard adhesive in particular starch and even more in particular a gelatinized starch suspension ("carrier") or starch milk with which the gelatinized starch suspension is mixed.

The invention furthermore relates to starch 5 for the preparation of corrugated cardboard adhesive using washing water from flexographic printing machines, characterized in that the starch contains at least one of the aforementioned additives and further, if necessary, a base, such selected amounts that the flexographic ink in the wash water does not adversely affect the viscosity and gelatinization point of the finished adhesive.

The amount in which the agent or the additive according to the invention is used depends on its nature and on the content of ink in the wash water used, originating from the flexographic printing machines. Apart from the silicates, the amount is generally 0.01-10% by weight, and preferably 0.05-5% by weight, based on the total amount of starch used for the preparation of the glue and the agent or addition .

For the silicates, the amount is generally 0.01-49% by weight, preferably 0.05-20% by weight, and in particular 0.1-6% by weight, based on the total amount of starch and silicate. .

To correct deviations from the gelatinization point, a base is used because otherwise the properties of the adhesive and the production speed of the corrugated machines must be adjusted. When these deviations occur, the base is applied in an amount selected so that the deviations are corrected.

The use of a base is not necessary when a silicate of, for example, sodium, potassium and / or calcium is used.

With regard to the amount of silicate, it is also noted that the upper limit is not critical because excess silicate has no harmful influence on the properties of the glue.

The additive according to the invention is added to a raw material for the preparation of the glue, in the 7903749 6 * in particular starch (milk or "carrier") or to the washing water, either in liquid or solid form. The silicates of sodium, potassium and calcium are available as powders and liquids and can thus be added in one of these forms to the starch, the starch milk or the gelatinized starch suspension. Solid silicates can be pre-incorporated into the starch by pulverizing with liquid silicates, and powdered silicates simply by blending without further ado. Powdered silicates have no free alkalinity, which could affect the stability of the mixture on storage.

The ratio of silicon to oxide of sodium, potassium and calcium in the silicates is not limited, but is usually between 2 and 2.4 for sodium silicate and between 3 and 3.5 for potassium silicate.

With silicates such good results are obtained that the wash water of the flexographic printing machines can be used not only in starch milk or gelatinized starch suspension ("carrier") as used in the preparation of starch glue according to the Stein-Hall process, but also in suspensions of unsupported partially gelatinized starch as used in the above second process, for continuous preparation, in particular gelatinizing the aqueous gelatinized starch suspension at elevated temperature.

A versatile product according to the invention as regards its application possibilities consists of a mixture of starch for the preparation of starch glue for the manufacture of corrugated board and silicate in such an amount that washing water from flexographic printing machines can be prepared for the preparation of the starch glue. used wherein the amount of silicate is generally 0.01-49 wt%, preferably 0.05-20 wt%, and more preferably 0.1-6 wt% based on the total amount of starch and silicate.

Example I

An adhesive for double-sided corrugated board with a thin layer of cardboard was prepared by preparing a starch milk from 450 l of water and 50 kg of starch and heating the milk at 7903749 * 7 at a temperature of 45 ° C. To the milk a solution of 9 kg of pure sodium carbonate in 20 l of water was added to effect gelatinization and thereby obtain a "carrier" or "first part". After 15 minutes of thorough stirring, 700 liters of water, 5 250 kg of starch and 6 kg of borax were added successively, which together form the starch milk or “second part.” After 15 minutes of stirring, the Lory viscosity was 19 seconds, the Brookfield viscosity was 290 cp. and the gelatinization point 54 ° C.

When the water in the "second part" was replaced by water containing 4 wt% chromographic yellow "1" type flexographic ink, the viscosity rose so much that the Lory viscosity could no longer be measured, the Brookfield viscosity was 29,000 cp and the gelatinization point had risen to 58 ° C. · This shows that the properties of the adhesive are drastically changed by the ink.

The adverse effect of the ink was offset by replacing the starch in the "second part" in the ink-containing wash water test with a dry mixture of 99.4 wt% starch and 0.6 wt% anhydrous calcium sulfate. The Lory viscosity 20 was 18 sec. and the Brookfield viscosity 250 cp. However, the gelatinization point had risen to 60 ° C but was lowered with 10.8 kg of sodium carbonate.

Example II

Proceeding according to example I, the following three tests were carried out: (1) with water in the "second part" without ink, (2) with water in the "second part" containing 4% by weight flexographic ink of the type chromate yellow "3", and (3) a mixture in the "second portion" of 99.5 wt% starch and 0.5 wt% anhydrous calcium sulfate.

The results are summarized in Table B below.

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TABLE B

Lory viscosity Brookfield Gelatinity, sec. viscosity ring point

cp ° C

5 ---—

Experiment (1) 19 280 54

Trial (2) 39 780 58

Test (3) 18 240 58 10 To lower the gelatinization point, sodium carbonate (about 1.7 kg) can be added.

Example III

The procedure was carried out according to Example X, Test 3, in which the mixture of starch and calcium sulfate was replaced by a mixture of 99% by weight of starch and 1% by weight of calcium oxalate.

The Lory viscosity was 20 sec., The Brookfield viscosity 280 cp and the gelatinization point 59.5 ° C. The gelatinization point can be corrected with about 1.6 kg of sodium carbonate.

These results show that calcium sulfate can be replaced by calcium oxalate with the same favorable results.

Example IV

The procedure of Example 1, Test 3, was carried out, in which the mixture of starch and calcium sulphate was replaced by a mixture of 98.25% by weight of starch and 1.75% by weight of magnesium-sulphate. The Lory viscosity was 22 sec., The Brookfield viscosity 410 cp and the gelatinization point 61 ° c. The gelatinization point can be corrected with 1.39 kg of sodium carbonate.

Example V

The procedure was as described in Example 1, Test 30 2, in which the chromate yellow "1" was replaced by "Orange 802" of

Millory that has an even less favorable effect on the adhesive. Furthermore, in Run 3 of Example I, the mixture of starch and calcium sulfate was replaced with a mixture of 95 wt% starch and 5 wt% iron (III) sulfate. The results are summarized in Table C below.

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TABLE C

Lory viscosity Brookfield visco-Gelatinization sec. density, cp point ° C

5 Trial (1) 19 290 54

Test (2) Immeasurable 34,800 58

Experiment (3) 18 470 69

The texture is somewhat short, but the glue is further acceptable except for the gelatinization point to be corrected with a significant amount of sodium carbonate. Therefore, iron (III) sulfate is not a primary consideration for counteracting the adverse effect of said flexographic ink.

Example VI

The procedure was carried out according to Example V, Test 3, in which the mixture of starch and iron (III) sulfate was replaced by a mixture of 99% by weight of starch and 1% by weight of powdered sodium silicate with a ratio of silicon and sodium oxide of 2. 06. The 20 Lory viscosity was 18 sec., The Brookfield viscosity 260 cp and the gelatinization point 56 ° C thus almost normal. These results show that sodium silicate is particularly suitable because it corrects both the viscosity and the gelatinization point.

Example VII

The procedure was carried out according to Example VI, using 2% by weight of the same sodium silicate instead of 1% by weight of sodium silicate. The Lory viscosity was 16 sec., The Brookfield viscosity 230 cp and the gelatinization point 55 ° C.

Since these results are practically no different from those of Example VI, it can be concluded that an excess of sodium silicate does not adversely affect the adhesive.

Example VIII

The procedure was carried out according to Example VII, leaving out the ink. The Lory viscosity was 35 19 sec., The Brookfield viscosity 250 cp and the gelatinization point 70 0 9 7-5 9

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10 54 ° C. These results confirm that the silicate does not have any harmful influence on the adhesive and that with a silicate it does not matter at all whether ordinary water or flexographic ink-containing water is used.

Example IX

A starch glue for the two-sided gluing of corrugated board was prepared according to the Stein-Hall process, using wash water containing flexographic ink in both the "carrier" or the "first part" and the "second part". The "carrier" was prepared from 450 L of wash water containing 4 wt% "Orange 802" from Millory, 50 kg mixture of 98 wt% starch and 2 wt% sodium silicate with a ratio of silicon and sodium oxide of 2.06, and 9 kg of pure sodium carbonate. The "second part" was prepared from 700 l of the aforementioned ink-containing wash water, 250 kg of the aforementioned mixture of starch and silicate and 6 kg of borax.

The Lory viscosity was 19 sec., The Brookfield viscosity 460 cp and the gelatinization point 58 ° C. Although the gelatinization point deviates little from the normal gelatinization point, a correction can be made with sodium carbonate (about 1 kg). However, this is usually not necessary in practice.

Example X.

An adhesive was prepared by the above second process, i.e. a starch adhesive without a carrier. To this end, a milk of starch (commercial quality) and a sodium carbonate solution with a concentration of 3.56% by weight, based on the starch, were mixed at a temperature of 39 ° C. The starch milk was prepared from 225 kg of starch and 705 l of water .

In a first run, tap water was used and the product was subjected to the action of sodium carbonate viscosext 30 for a time "x" long enough to achieve a Brabender of 300 units.

In a second test, water containing a flexographic ink of the "Orange 802" type was used at a concentration of 4% by weight. And the time "x" was determined.

In a third test, the water of the second test was used, to which a powdered mixture of 97% wt. % of starch and 3% by weight of sodium carbonate with a ratio of silicon and sodium oxide of 2.06 were added. This milk was also subjected to the action of sodium carbonate, the time "x" being measured.

The third test was repeated in a fourth test in which the water contained no ink. The time "x" was again determined. The measured values for "x" are summarized in Table D below.

TABLE D

10 _____________

Swelling time "x" required to achieve a Brabender viscosity of 300 units, min.

Test (1) blank 22

Test (2) no swelling ^ Test (3) 21

Experiment (4) 26

The results of the first and third tests show that the sodium silicate counteracts the deleterious effect of the ink 20 as it appears from the second test in which swelling was inhibited. Furthermore, the fourth test shows that the silicate per se does not significantly change the properties of the glue.

The tests were repeated in large amounts: 250 kg of starch in 705 l of water at a temperature of 36 ° C and 8 kg of sodium carbonate in 215 l of water at a temperature of 54 ° C. The suspension and solution were mixed at a temperature of 39 ° C. The swelling time "x" was adjusted to 20 min with a 3.56 wt% aqueous sodium carbonate solution, at the end of which time 4.5 kg of boric acid was added. The Lory viscosity,. Brookfield viscosity and the gelatinization point are summarized in Table E below.

35 79 OS 7 43 Λ -. * 12 TABLE Ε

Lory viscosity Brookfield visco-Gelatinization sec. density, cp point ° C

^ Trial (1) Blank 10 780 50

Do not test (2) swelling

Test (3) 11 1280 55 Test (4) 11.5 1000 50.5 10 Comparing the results of Test (1) and Test (4) shows that the sodium silicate slightly slows swelling and slightly increases the final viscosity. When ink is present as in Test 3, the Lory viscosity is acceptable. The texture of the glue is slightly shorter. Although the gelatinization point has increased, the swelling time has stabilized.

Example XI

The procedure was carried out according to Example I, in the second test the chromate yellow "1" was replaced by Rouge 824 vein Millory, and in the third test the mixture of starch 20 and calcium sulfate was mixed with a mixture of 98 wt% starch and 2 wt .% Portland cement. The viscosities and gelatinization point are listed in Table F below,

TABLE F

25 Lory viscosity Brookfield fish- Gelatinization

see. vosity, cp point ° C

Experiment (1) 19 280 54

Test (2) immeasurable 14,200 59

Test (3) 43 410 55.5 30 ---: ---; -

Although the cement appears to be ineffective, it should be considered that the flexographic ink used in these tests is significantly more deleterious to the properties of the adhesive than the ink blends usually present in wash water from flexographic printing machines.

7908749 Η.

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Example XIX

The procedure was carried out according to Example I, in which in the second test the chromate yellow "1" was replaced by Rouge 824 from Millory and in the third test the mixture of starch 5 and calcium sulphate with a mixture of 99% by weight of starch and 1% by weight, % powdered activated carbon (available from CECA SA, 78140 Velizy-Villacoublay). The viscosities and gelatinization point are listed in Table G below.

TABLE G

10 _______

Lory viscosity Brookfield vis- Gelatinization sec. cosity, cp point ° C

Experiment (1) 19 280 54

Test (2) immeasurable 14,200 59

Test (3) 43 550 57

The activated charcoal appears to be ineffective, but it should be considered that the ink used in these tests is significantly more harmful to the adhesive than the ink blends usually present in wash water from flexographic printing machines. The gelatinization point can be adjusted with a little alkali if desired.

25 7908749

Claims (13)

1. A method of preparing an adhesive, in particular for corrugated board manufacture, using washing water from cleaning flexographic printing machines, characterized in that the adhesive is desensitized from the ink present in the washing water by adding raw materials for the glue, in particular starch, to the washing water, to wholly or partly gelatinized starch and / or to starch milk with which wholly gelatinised starch is mixed before adding the washing water and at pH 3 customary for the preparation of corrugated cardboard glue + a salt and / or oxide of Ca, Mg, Mn, Ni, Ba, Co, Cr, Al, Fe, Zn, Sr, Pb, Sn, Ti, V, Cu, Mo, Cd, Cb, W and / or Add bi, silicoaluminate, activated carbon, cement and / or silicate, and if necessary a base, all this in such an amount that the changes in the viscosity and gelation point of the glue caused by the ink triggered, are acceptable. Method according to claim 1, characterized in that as a means against the sensitivity of the adhesive to flexographic ink a salt and / or oxide of Ca, Mg, Mn, Ni, Co, Cr 20 and / or Fe3 +, silico is used. -aluminate, activated carbon and / or cement. Method according to claim 1, characterized in that a silicate is used as an agent against the sensitivity of the adhesive to flexographic ink. 4. Agent against the sensitivity of glue for ink, in particular against the sensitivity of glue for the corrugated cardboard manufacture of ink present in the wash water from the cleaning of flexographic printing machines and intended for use in preparing the aforementioned glue at usual pH, characterized in that the agent consists of a salt and / or oxide of Ca, Mg, Mn, 30 Ni, Ba, Co, Cr, Al, Fe3 +, Zn, Sr, Pb, Sn, Ti, V, Cu, Mo, Cd, Sb, W. and / or Bi, silicoaluminate, activated carbon, cement and / or silicate, and that the agent is added to the raw material for the glue, in particular starch and more in particular fully or partly gelatinized starch or starch milk with which it is fully gelatinized 35 starch is mixed, or to the wash water. * 7908749 Agent according to claim 4, characterized in that the agent consists of a salt and / or oxide of Ca, Mg, Mn, Ni, Co, Cr, and / or Fe 2+, silicoaluminate, activated carbon and / or cement. 6. Agent according to claim 4, characterized in that the agent consists of a silicate. Starch for the preparation of glue, in particular glue for corrugated board manufacture using washing water from the cleaning of flexographic printing machines, characterized in that the starch contains an agent according to claims 4-6. Process according to claims 1 and 2, characterized in that, apart from silicate, the agent is used in an amount of 0.01-10% by weight and preferably 0.05-5% by weight calculated on the total amount of starch and the means. Process according to claim 3, characterized in that silicate is used in an amount of 0.01-49% by weight and preferably 0.05-20% by weight, based on the total amount of starch and silicate. 10. Process according to claim 3, characterized in that silicate is used in an amount of 0.1-6% by weight, based on the total amount of starch and silicate. 11. Starch according to claim 7, characterized in that, apart from silicate, the amount of the agent in the starch is 0.01-10% by weight and preferably 0.05-5% by weight, calculated on the total amount of starch. and the means. Starch according to claim 7, characterized in that the starch contains silicate in an amount of 0.01-49% by weight and preferably 0.5-20% by weight and more preferably 0.1-6% by weight. % based on the total amount of starch and silicate. 13. Means and methods as described in the description and examples. 35 7908749