SK113096A3 - Agent for deinking printing ink and a method of deinking - Google Patents

Abstract

A method of de-inking non-impact printed paper comprises contacting repulped paper with a formulation comprised of a derivatized ethylene oxide/propylene oxide polymer and a petroleum hydrocarbon distillate. The process separates the ink from the paper and agglomerates the separated ink into particles of a size sufficient that they can be efficiently removed from the paper fibers.

Description

Technical field

The present invention relates to methods and means for removing color from paper containing printed matter to which non-impact printing methods have been applied. More specifically, the invention relates to methods and compositions that separate ink from paper and agglomerate the separate ink into particles of a size sufficient to effectively remove them from the paper.

BACKGROUND OF THE INVENTION

Currently, the increase in environmental conscience has prompted the increasing use of recycled paper. At the same time, the increasing use of non-contact reprographic printing processes such as electrographic photocopying (eg xerography), laser printing, ink jet printing has greatly increased the difficulties faced by paper recycling methods.

When recycled paper is recycled, the ink must be substantially or preferably completely removed, allowing the production of high quality paper with recycled or secondary fibers. Conventional paint removal methods remove conventional water or oil based paints by mechanically pulping the printed paper and then contacting the pulped paper with an aqueous medium containing a surfactant to remove the color from the fiber slurry. The separated color is then removed by washing or flotation.

However, conventional color removal methods cannot be satisfactorily used to recycle color-printed paper for touch-free printing. This drawback results from the composition of inks for touchless printing. In general, the non-contact printing inks are formed by a thermoplastic binder which, during conventional pulping and de-inking, produces particles that are too large to be removed by washing or flotation, but too small to satisfactorily be removed by screening or centrifugation.

Several methods have been verified to agglomerate these polymer-based paints into larger, more compact particles that can be removed by sieve or centrifugation. For example, U.S. Pat. Nos. 4,820,379 and 5,102,500 disclose agglomeration of reprographic inks with alkoxy terminated polyethylene oxide additives in the presence of polymeric materials and optionally a chelating agent. U.S. Pat. No. 5,141,598 discloses color removal from electrostatically printed paper using a mixture of aliphatic petroleum distillate, alkyffenoxy (ethyleneoxy) ethanol and ethoxylated polyoxypropylene glycol. The blend has a combined HLB of less than 10 and a weight ratio of 6: 1: 3.

SUMMARY OF THE INVENTION

Correspondingly, the present invention is directed to a method for removing color from a non-impact printed paper, which substantially eliminates one or more of the problems due to the limitations and disadvantages of currently used methods of color removal. In one aspect, the present invention provides a method of de-inking, wherein reprographic or biased inks are removed from the fibrous paper fibers and agglomerated to a size sufficient to allow them to be removed from the fibers. The method comprises the step of contacting the fibrous fibers comprising a non-contacting printed article with the added composition for a time and at a temperature sufficient to separate the fibrous paper color and agglomerate the separated color into particles of a size sufficient to allow removal from the fibers. The added composition comprises (1) 85 to 10% by weight of at least one petroleum distillate and (2) 15 to 90% by weight of at least one derivatized ethylene oxide / propylene oxide polymer having the structural formula I:

R (CH ₂ CH ₂ -O) _x (CHCH ₂ -O) _y H.

CH ₃ wherein both x and y are integers from 1 to 20 and R is a derivatizing radical selected from

(a) an aliphatic alcohol residue having the formula

R-C - ^ - o;

(b) an aliphatic acid residue having the formula:

(c) a phenolic residue of the formula:

where R- | is a linear or branched, saturated or unsaturated hydrocarbon chain having 1 to 20 carbon atoms.

The invention also provides a composition useful for carrying out the method. The composition comprises (1) 85 to 10% by weight of at least one petroleum distillate; and (2) 15 to 90% by weight of at least one derivatized ethylene oxide / propylene oxide polymer of Formula I:

RíCHjCHj-O-VCCH-CH-O ^ H

CH, (1) wherein x and y are integers from 1 to 20 and R is a derivatizing radical selected from (a) an aliphatic alcohol moiety having the formula:

RpCHj -O-;

(b) an aliphatic acid residue having the formula:

about

R ^ _R c;

about-

(c) a phenolic residue of the formula:

where R- | is a linear or branched, saturated or unsaturated hydrocarbon chain having 1 to 20 carbon atoms.

DETAILED DESCRIPTION OF THE INVENTION

When removing ink from the waste paper containing the contactless printed material, the paper is typically treated in a water pulper to form an aqueous slurry of spun paper fibers. Typically, the fiber slurries contain 3 to 20, and often about 4 to 8 weight percent of the filament paper fibers based on the total weight of the slurry.

Additives commonly used in paint stripping operations include surfactants, bleaches, brighteners, emollients, antifoams, dispersants, and chelating agents. Commonly used de-inking pulping agents such as ethoxylated alcohols and phenolic ethoxylates may also be present. Phenol ethoxylates are especially used when the slurry contains a mixture of contactless printed paper together with conventional touch printed paper. These additives and additives may be added to the aqueous pulpers at any time before, during or after the pulping. As the crushing itself lasts only a very short time, additives are usually added to the water crusher at the beginning of the crushing operation.

To remove ink from the contactless printed paper in accordance with the present invention, the fibrous paper fibers are contacted with a composition comprising at least one petroleum distillate and at least one polymer of formula I below. The composition typically comprises 10 to 85% by weight of a petroleum distillate, preferably 15 to 40%, and 5 to 90% by weight of a derivatized ethylene oxide / propylene oxide polymer of formula I, preferably 60 to 85%, more preferably 65 to 80%. A preferred composition comprises about 25% petroleum distillate and 75% polymer.

The petroleum distillate is preferably a relatively high boiling hydrocarbon fraction having a boiling point between about 185 ° C and 275 ° C. Such a fraction typically comprises a mixture of aliphatic and naphthenic hydrocarbons with a low level of aromatic hydrocarbons. Petroleum distillates with these characteristics are commercially available, for example, under the trade names Vista LPA-140 (CAS # 6472-47-8), boiling range 187-232 ° C, Vista LPA-210 (CAS # 64742-47-8 ), boiling range 203-278 ° C, both supplied by Vista Chemical Company, and ArcoPrime 55 (CAS # 8042-47-5) supplied by Lyondell Petrochemical Company.

The polymers used in the paint stripping process of the invention are derivatized ethylene oxide / propylene oxide polymers. These polymers, which may be random or block copolymers, are represented by the following formula I:

RICHjCHj-O-CH = CH-O-JY-H

CH ₃ (I)

Commercially available polymers of Formula I are supplied by Chemax, Inc. under the trade name Chemal DA-5P8, PPG Industries, Inc. under the trade name

Macol LF110 and Macol LF120, and BASF as Afranitf.

The ratio of ethylene oxide to propylene oxide units, x: y, in the polymer may vary from about 1 to 20 to 20 to 1. Preferably, the ratio is not greater than about 1 to 1, and more preferably less than about 1 to 1, i. j. propylene oxide units will prevail. The ethylene oxide and propylene oxide units can be arranged in a random or block configuration in the polymer structure.

As shown in Formula I, the derivatizing radical R is derived from (a) a linear or branched, saturated or unsaturated aliphatic alcohol, (b) a saturated or unsaturated aliphatic carboxylic acid, or (c) a phenolic residue.

The aliphatic alcohol residue (a) has the formula:

R _r CH ₂ -O-;

The aliphatic acid residue (b) has the formula:

about-

Phenolic residue (c) has the formula:

about-

In each of formulas (a), (b) and (c), R 1 is a linear or branched, saturated or unsaturated hydrocarbon chain of 1 to 20 carbon atoms.

When the derivatizing radical R is an alcohol moiety (a), the radical R @ 1 is preferably a saturated radial of 1 to 20 and more preferably of 8 to 14 carbon atoms in either a linear or branched chain. When the residue is branched, it is preferred that it has about 5 to 10 carbon atoms in the long chain.

When the derivatizing radial R represents an aliphatic acid radical (b), it is R-, preferably a linear radical of 5 to 10 and more preferably of 8 to 12 carbon atoms. Preferably R 1 is in this case, saturated or contains more than 1 carbon-carbon bond. In another preferred embodiment, the aliphatic acid residue (b) is a fatty acid residue. Preferred fatty acid residues include oleic and linoleic fatty acids.

When the derivatizing radical R represents a phenolic radical (c), the phenolic radical may be derived from ortho-, meta- and para-phenol, preferably from parafenol. R 6 is preferably a linear saturated aliphatic radical of 1 to 30, more preferably of 8 to 14 carbon atoms.

The molecular weight of the polymer of formula I comprising a derivatizing radical may be between about 400 and 8000. Preferably, the molecular weight is between 400 and 2000, and most preferably between about 600 and 1400.

In the color removal method of the invention, the aqueous slurry of fibers is contacted with the additive at a concentration and for a time and at a temperature sufficient to remove color from the paper fibers and cause agglomeration of the removed color into particles sufficiently large to allow removal from the fibers. paper by methods known in the art, preferably by sieving or centrifugation. The additive may be used at a level of 2.27 to 13.6 kg (5 to 10 pounds), preferably 4.5 to 9 kg (10 to 20 pounds) per ton (tons) of dry weight of the fibers.

Other additives commonly used in the color removal processes discussed above with or as part of the additive composition of the present invention may also be added. A person skilled in the art is familiar with a number of additives commonly used in paint removal processes.

In the color removal method of the invention, the paper may first be fibrillated and then contacted with the additive or the fibrillation and de-inking may take place simultaneously. The present process is preferred, as in a sequential or simultaneous process a slurry may be formed by methods known in the art.

The paper to be de-inked may be treated in an aqueous pulper or other de-inking machine with an additive composition of the invention to form an aqueous slurry of about 3 to 20, preferably about 4 to 8, percent by weight of dry fibers based on the total weight of the slurry. . The slurry is preferably contacted with the additive at a temperature above the softening point of the ink, preferably when the ink becomes tacky and agglomerates. For example, the temperature required is about 40 to 100 ° C, preferably about 65 to 80 ° C, and most preferably about 70 ° C. The slurry is preferably contacted with the adjuvant at a pH of about 6 to 13, preferably a pH of 8 to 11, and most preferably a pH of about 11. A person skilled in the art will understand that these conditions may vary depending on the particular composition of color or colors included in given the bleaching process.

The ink may be separated from the fibrillated fibers and agglomerated into particles to be removed sequentially or substantially simultaneously. Again, it is advantageous to simultaneously de-ink and agglomerate. Generally, under these conditions, about 5 to 60 minutes of time is required to complete fiberizing and de-inking of the paper.

Color formulations (often referred to as tenors) used in contactless printing generally consist of low molecular weight thermoplastic polymers and pigments, typically carbon blacks, and color pigments are also often used. The polymers used are, for example, low molecular weight polystyrene, styrene / methacrylate copolymers, butadienes and polyesters. Sometimes waxes are mixed into the paints to improve their fixation efficiency. In general, the main requirements for these polymers are: (1) they must have a melting point between 120 and 200 ° C; (2) they must be stable at temperatures up to about 54 ° C; (3) they must melt on paper at about 150 ° C; and (4) have a glass transition temperature (softening point) between about 65 and 75 ° C.

Thus, preferably, the slurry is contacted with the additive composition of the invention at a temperature where the thermoplastic paint binder becomes tacky and the ink particles are more easily agglomerated into the tacky particles. Preferred agglomerated particles have a diameter of at least about 175 µm, and more preferably at least about 200 µm.

Upon completion of pulping and agglomeration of the particles, the slurry temperature is preferably lowered to a temperature below the softening point of the polymer, preferably to about 55 ° C or lower. At this point, the agglomerated polymer particles solidify to a much stronger non-tacky state, allowing them to be easily removed from the slurry by methods known in the art. This removal is preferably carried out on a sieve or by centrifugation. The cooling temperature is not critical, but needs to be sufficiently low to allow the thermoplastic binder to solidify to a sufficiently tack-free state.

DETAILED DESCRIPTION OF THE INVENTION

The following examples illustrate the invention. The examples illustrate but do not limit the present invention.

Example 1

The color of the xerographic printed paper was removed using the additive composition of the present invention. Each preparation was made from 25% by weight of petroleum distillate and 75% by weight of derivatized ethylene oxide / propylene oxide polymer according to the following list.

Preparation A - Petroleum distillate: Vista LPA-140

- Derivatized ethylene oxide / propylene oxide polymer

haphazardly ch ₃ ch ₃ Preparation B - Oil distillate: Vista LPA-140

-Derivatized ethylene oxide / propylene oxide polymer.

block CH 3 CH (CH _{2) r} -O- (CH ₂ CH _z O) ₅ - (CH-CH ₂ O) ₈ H CH ₃ CH ₃

Preparation C - Petroleum distillate: Vista LPA-140

- Derivatized ethylene oxide / propylene oxide polymer

block CH ₃ (CH ₂ ) ₍ 11.13 ₎ -O- (CH ₂ CH ₂ -O) ₅ - (CH-CH ₂ -O) ₈ -H ₃

Preparation D - Petroleum distillate: Vista LPA-140

- Derivatized ethylene oxide / propylene oxide polymer

block CH ₃ (CH ₂ ) _r CH = CH- (CH ₂ ) ₇ -CO- (CH ₂ CH ₂ -O) ₅ - (CHCH ₂ -O) ₃ -H o ch ₃

Preparation E - Petroleum distillate: Vista LPA-140

- Derivatized ethylene oxide / propylene oxide polymer

block CH ₃ CH ₃ CH 2 CH 2 O-CCH ₃ CH ₃ J ₃ -CH 2 CH ₃ CH ₃ CH ₃

A slurry of 4% by weight xerographic printed paper in aqueous liquor was prepared at pH 11.0 and 70 ° C. Each of the formulations A-E was added to the cut slurry at a concentration of about 9 kg (20 pounds) per ton (tons) of slurry. Spinning / decoloration was performed at 70 ° C for 30 minutes, then the temperature was lowered to 40 ° C to solidify the agglomerated paint / polymer particles. At the same time as the test runs, control experiments were carried out without additive and only with petroleum distillate.

The fibers were then washed at 0.5% slurry consistency in water on a 4 mm sieve (5 mesh), then on a 2 mm sieve (10 mesh) and finally on a 1 mm sieve (20 mesh) to remove agglomerated paint particles.

The polymer particle size was measured on an Thomas optical image analyzer in all experiments. It was found that using a composition of the invention consistently obtained a particle size greater than 200 µm, allowing the particles to be easily removed on the screen. Conversely, when the composition of the invention was not used, a significant number of particles smaller than 200 µm were formed which were not removed on the screen. These results are shown in Table I.

Table I

agent Average particle size (μΠΊ) Minimum particle size (μΠΊ) Particle size range (Mm) A 1300 250 250-2100 B 1200 275 275-1700 C 1400 220 220-2300 D 1200 320 320-1900 E 1400 280 280-1650 only petroleum distillate <100 <50 <50-350 inspection <100 <50 <50-350

Each batch of recycled fibers obtained in this example was processed into test sheets using conventional paper laboratory methods. To evaluate the quality, the whiteness of each sheet was determined using a General Electric whiteness meter.

Each of samples A to E showed a whiteness of paper between 80 and 83, indicating that little or no color remained in the paper. In contrast, a control experiment where no post-treatment according to the invention was used had a whiteness value of 76.3, indicating that significantly more color remained in this paper than in the samples A to E. The oil distillate preparation had a whiteness value of 76.5 . The whiteness of the original paper in its paper in its original state was 84.5. Thus, the present invention successfully recycled the xerographic paper to its closest original whiteness by removing the greatest amount of color.

Example 2

Using the same procedures and additives as in Example 1, the dose of laser-printed paper was decolorized. The color / polymer particles were removed on a sieve and their particle size was measured. The results are shown in Table II.

Table II

agent Average particle size (μπι) ....... Minimum particle size (µm) Particle size range (pm) A 1000 230 230-2200 B 900 270 270-1500 C 1100 240 240-1900 D 1000 250 250-1700 E 800 240 240-1200 only petroleum distillate <100 <50 <50-350 inspection <100 <50 <50-350

The whiteness of the fiber bleach test sheets of the invention ranged from about 77.8 to 80.1. This is compared with a whiteness of 75.4 for the control experiment, 84.5 for the original paper in its original state, 76.5 for the preparation using only petroleum distillate.

Claims (10)

PATENT CLAIMS h / w ·. A composition for use in removing color from paper containing a non-impact printed material, i. characterized in that it comprises: (1) 85 to 10% by weight of at least one petroleum distillate; and (2) 15 to 90% by weight of at least one derivatized ethylene oxide / propylene oxide polymer of formula I R- (CH ₂ CH ₂ O) _x - (CH-CH ₂ -O-) _f H ch ₃ where both x and y are integers from 1 to 20 and R is a derivatizing radical selected from (a) an aliphatic alcohol residue having the formula R ^CH CHO O; (b) an aliphatic acid residue having the formula: (c) a phenolic residue having the formula: wherein R- (is a linear or branched, saturated or unsaturated hydrocarbon chain having 1 to 20 carbon atoms). Composition according to claim 1, characterized in that the ratio of ethylene oxide to propylene oxide in the polymer is less than 1 to 1. Composition according to claim 1, characterized in that the petroleum distillate is a mixture of aliphatic and naphthenic hydrocarbons having a boiling point between about 185 and 275 ° C, preferably VISTA LPA-140 product. The composition according to claim 1, wherein the derivatized ethylene oxide / propylene oxide polymer is haphazardly CH ₃ CH (CH ₂ ) ₍ 9.11 ₎ -O- (CH ₂ CH ₂ -O) ₂ - (CH-CH ₂ -O) _e -H ch ₃ ch ₃ or block CH ₃ CH (CH ₂ ) _r O- (CH ₂ CH ₂ -O) ₅ - (CH-CH ₂ -O) ₈ -H ₃ CH 3 or block CH ₃ (CH ₂ ) ₍ 11.12 ₎ -O- (CH ₂ CH ₂ -O) _s CH ₃ CH-CH ₂ -O ₁₈ -H ₃ or block CH3 (CH ₂ ) ₇ -CH = CH- (CH ₂ ) _r CO (CH ₂ CH ₂ -O) ₅ (CH-CH ₂ -O) ₈ -H _or OCH ₃ block CH 3 - (CH) - (CH ₂ ) y C ₆ H ₄ -O- (CH ₂ CH _r O) _s <CH-CH 2 -O) ₈ -H ch ₃ ch ₃ A method for removing ink from a contactless printed paper, comprising the step of contacting the fibrous paper fibers comprising the contactless printed material with an additive agent according to any one of claims 1-4 for a time and at a temperature sufficient to separate the ink from the fibrous paper. and to agglomerate the separated color into particles of a size sufficient to allow removal thereof from the fibers. The method of claim 5, further comprising the steps of lowering the temperature to obtain solid and non-tacky agglomerated color particles and removing agglomerated color particles from said fibers. The method of claim 5 or 6, wherein the contacting step comprises a first step of separating the color from the fiber followed by a second step of agglomerating the separated color into particles of a size that allows them to be removed from the fibers. The method of claim 5 or 6, wherein the contacting step substantially simultaneously separates the color from the fibers and agglomerates the separated color into particles of a size that allows them to be removed from the fibers. Method according to any one of claims 5-8, characterized in that the contacting step is carried out at a temperature ranging from 60 ° C to 80 ° C and / or the composition is used in an amount of about 2.27 to 13.6 kg (5). up to 30 pounds) per ton (tons) of dry fiber weight. Method according to any one of claims 5-9, characterized in that the agglomerated color is removed on a sieve or by centrifugation.