FI73015B - FOERFARANDEN FOER ATT AVLAEGSNA BLAECK FRAON SEKUNDAERA FIBER. - Google Patents

Description

7301 5

The invention relates to methods for removing ink or other contaminants from waste and scrap cellulose fibers (i.e., not first-time or original fibers) or fiber sources. In particular, the invention relates to washing methods for removing ink from recycled cellulosic fibers, in particular to washing methods using aqueous media containing surfactant detergents.

At least since the days of the ancient Egyptians, man has found it advantageous to make and use paper. Until very recently, the majority of paper around the world has been made by converting paper into original, ie previously unused, fibers, such as vegetable fibers such as wood or cotton fibers. Recently, a significant portion of the 15 cellulosic pulps used in papermaking in the United States of America have been waste or scrap fibers, i.e., fibers that have been converted to paper at least once in the past. Categories of such recycled fibers include waste pulp, which is treated waste and recycled pulp from a paper mill, and recycled fibers which have previously been completely converted to their end-use and are generally returned to the paper mill for re-use. Both of these 25 types of fibers are hereinafter referred to as "waste fibers".

According to the invention, recycled fibers are preferably used from which the ink can be removed.

To supplement or replace the original pulps with waste fibers of approximately the same quality, such fibers, e.g., business accounting paper, newsprint, magazine paper, computer writing paper, paperboard, etc., must be treated with ink and numerous other non-cellulosic materials, binders, binders, binders, or contaminants. to remove wet strength resins, pigments initially added to the paper to impart desired properties such as wet bone strength, color, gloss, etc. to the paper). Each 2,70101

The first step in any conventional treatment to remove harmful non-cellulosic contaminants is the re-defibering of such materials, i.e. the treatment of recycled waste fibers to restore them to the shape of actual cellulose fibers. Refiberization (usually performed by contacting these recycled fibers with a heated, usually basic aqueous medium, which may contain a wide variety of processing aids or chemicals) seeks to detach and separate non-cellulosic materials from cellulosic fibers so that these non-cellulosic fibers contaminants can be isolated from these fibers.

Conventionally, two different and very different methods are used to isolate non-cellulosic components after re-fiberization and thus to produce ink-purified fibers. Both of these methods are referred to as “flotation” and “washing.” The application of flotation methods to isolate ink 20 is generally based on passing an air bubble stream through a water stream of dispersed cellulosic fibers (i.e., re-fiberized cellulosic fiber slurry). promote the adhesion of the ink particles to air bubbles.The air bubbles rise to the surface of the fibrous sludge and carry the ink particles with them and thus develop foam which can be removed from the flotation cell.This method is based on the uneven distribution of ink and fibers in the sludge formation foam.

30 In other words, it is assumed that the fibers remain low in the slurry, while the ink rises to the surface with the bubbles. In the case of the "washing method", in turn, the ink and the fibers are more or less evenly distributed throughout the slurry, and foaming or the formation of bubbles 35 are not particularly desirable, although these phenomena also occur. The purpose of the washing method is to cause the ink to migrate from the fibers to the aqueous medium and then to separate the aqueous medium from the fibers. Thus, the washing process typically involves re-defibering the waste fibers in an ink-removing aqueous medium, preferably under low-foaming conditions, by which the ink (and any other non-cellulosic contaminants present) is mechanically and / or chemically removed from the fibers and more or less evenly distributed throughout. medium. This is followed by a at least partial modification of the aqueous medium, e.g. dilution and / or screening, after the re-fiberization step.

10 The ink can be removed to some extent from the fibers by the washing method alone under the influence of water mixed with the fibers. However, most of the ink can be removed by mixing a surfactant with water.

This surfactant detergent can enhance the ability of the aqueous medium 15 to remove ink from the fibers. Unfortunately, some surfactant detergents that effectively facilitate the removal of ink from the fibers do not particularly effectively maintain low-foam conditions. Conventional deinking treatments in which the surfactant detergents 20 have been used in a wash-type deinking treatment have often developed excessive foaming (in the re-fiberization, washing, separation or cleaning steps) to a degree where different overflow tanks or removal boxes have to be used. receiving. One proposed solution to this problem is based on the addition of chemical defoamers to the pulp to reduce foam. These defoaming chemicals increase the overall efficiency of ink removal, but their primary function is to reduce foaming alone.

Ink removal performed using a variety of conventional flotation methods can have several disadvantages. First, the capital investment in flotation treatment is higher than the capital investment required in washing treatment.

35 Second, the flotation treatment is effective only if the pulp fed has an appropriate consistency. Variations in this consistency cause variations in the rate at which air bubbles rise through the flow of fibers, which in turn develop detrimental variations in the rate at which contaminants are removed from the slurry. Other variations 5 in the pulp fed can also cause difficulties. For example, if the waste fibers are from specially coated paper, the foaming medium may be adversely affected by the natural or synthetic sizing agents or other non-cellulosic materials present in this paper, as described in DE-10 publication 2,143,912, published March 8, 1973, p. 2, third paragraph. In addition, the weight percentage of cellulosic fibers in the fed pulp when applying the flotation treatment is generally lower than during the washing treatment, which forces the use of more water. Third, the diameter of the bubbles evolving in the flotation-15 cell must be within certain limits in order for these bubbles to efficiently carry ink particles from the cellulosic fibers. The development of fixed-size air bubbles is not technically difficult but complicates processing. Finally, foam treatments typically generate foam that must be collected, drained and returned to the environment.

The object of the present invention is to avoid or reduce the disadvantages of washing-type ink removal methods and at the same time to achieve the advantages of these methods, especially compared to more complex, more capital-intensive and more sensitive flotation methods.

Thanks to the invention, an even better washing method is obtained in which non-ionic surfactants belonging to a certain class lead to both controlled foaming (i.e., defoaming phenomena) and high ink removal efficiency. The washing-type ink removal methods of this invention generate little or no foam. Another demonstration of the effectiveness of the process of the invention has surprisingly been found in the key step of treatment 35 (i.e., re-fiberization) to be performed at relatively low temperatures. In addition, the type of aqueous medium used for re-fiberization, i.e. washing, can be simplified because a single nonionic surfactant selected from the class of surfactants (or, if desired, a combination of surfactants selected from this class) can be used and thus at the same time achieving both very high ink removal efficiency and good defoaming effects.

In short, the invention provides an improved washing process for producing substantially deflated waste fibers, one step of which comprises: suspending these waste fibers in a hot aqueous medium heated to a temperature in the range of about 27 to about 82, preferably 35 to 60 ° C; a surfactant is present having an oxyethylene glycol chain in which the hydroxyl at one end of the chain has been replaced by an aliphatic or alkyl aromatic ether group and the hydroxyl at the other end has been replaced by a polyoxypropylene group or a benzyl ether group.

In the process of the invention, the contaminated waste fibers are mixed with water and a surfactant detergent, which causes the contaminants, e.g. ink, to separate from the fibers and more evenly distributed in the aqueous medium, after which the substantially released fibers are separated or isolated from the contaminated aqueous medium, e.g. by centrifugation, decantation, decantation. especially by screening. After the decontaminated fibers have been separated or recovered from the aqueous medium, the treatment can be continued with a concentration or dilution step, followed by other washing-type steps, e.g., dilution and / or screening, these steps can be performed by mixing the diluted fiber slurries. In the practice of the invention, the removal of ink is particularly advantageously initiated by re-fiberizing the waste fibers, whereby the surfactant detergent used according to the invention may be present during the re-fiberization step.

6 73015

Surprisingly, the effectiveness of the surfactant detergents used in accordance with this invention, as determined by standard fiber whiteness tests, does not correlate with similar whiteness tests used to determine the effectiveness of cotton washing. Thus, it is difficult to explain the high level of ink removal efficiency achieved by using the surfactant detergents of the invention. The invention is not bound by any theory, but it is now assumed that a certain balance between hydrophilic and hydrophobic or lipophilic properties can be achieved by modifying the oxyethylene glycol chain as mentioned above, and this balance emphasizes both deinking efficiency and defoaming. Thus, the aliphatic or alkyl aromatic ether of oxyethylene glycol 15 terminates in either a benzyl ether group or a polyoxypropylene group, which contributes at least as much to the balance of hydrophobic and hydrophilic properties as the benzyl ether group would have done instead. The resulting non-ionic surfactant detergent has a "defoaming temperature" (defined below), and is typically above room temperature, but preferably not above 82 ° C, with a typical "defoaming temperature" in the range of 10 to 82 ° C. ° C, optionally below 60 ° C.

The invention is illustrated by the accompanying drawings, in which Figures 1 and 2 illustrate the isotherms of the foam dissipation ability of the various surfactant detergents of the invention (as defined below).

In this application, the following 30 meanings have the following meanings; "ink removal" means the actual chemical removal of ink in which the aqueous medium chemically removes ink from the waste fibers. Such chemical de-inking must be distinguished from "mechanical" de-inking, in which the action of water in a heavily mixed water-35 mass physically removes ink from the surface of the fibers and disperses or distributes this ink throughout the aqueous medium.

7 73015

The phrase "evenly distributed" means a suspended and / or dispersed and / or dissolved substance. Dispersed materials or dispersed phases are considered colloidal and / or non-settling, while suspended materials may settle over time.

The terms "deinking" and "decontamination" are generally used interchangeably herein to mean the removal of non-cellulosic contaminants from waste fibers. Such contaminants typically include printing ink or other types of inks (including ink flaps, dyes such as dyes or pigments, etc.) but may also include coatings, binders, paper pigments, adhesives, adhesives, and any other contaminants typically present in such inks. jätekuiduissa.

15 "Foam Dissipation Temperature" measures the behavior of a surfactant in an aqueous medium, and this term is more commonly used as an alternative to the well-known same spot test. The inventors of this application have found that foam decomposition temperature measurements provide a more reliable indication of the ability of a given surfactant detergent to remove foam than conventional cloud point determinations, especially in paper mill handling and ink removal operations. For some surfactant detergents, the defoaming temperature is essentially the same as the cloud point temperature determined from a 1% solution. However, when a nonionic surfactant with a high ethylene oxide to propylene oxide ratio (E0 / PO0 ratio) is used, the foam disposal temperature and the cloud point temperature can differ considerably, quite under actual ink removal conditions.

The defoaming temperatures are measured by adding about 0.1% by weight of the nonionic surfactant to be tested to 3 liters of temperature-controlled cold water in a 3-liter metal cup. Extending about 60 cm upward from the edge 35 of this cup is a glass cylinder for collecting the foam developing in this cup, and this glass β 73015 cylinder has a vertical scale for measuring the height of the developing foam column. Near the open end of the glass cylinder is a 30/15 "V-Jet" syringe nozzle directed into the cup, which is connected to a pressure-adjustable water-5 pump. This water pump circulates the contents of the goblet through the nozzle. For the assays used herein, the pump applies a pressure of 70 kPa to the nozzle. Shortly after the pump is started, an equilibrium foam height develops in the glass cylinder, and this equilibrium weight height is considered to be a characteristic of a given surfactant detergent and aqueous solution at a given temperature. At this point, the temperature of the water in the tank is gradually raised and the height of the foam column is recorded at approximately 2.8 ° C intervals. The temperature at which the height of the foam column 15 drops to a height of about 7.5 to 13 cm above the surface of the water in the goblet is said to be the defoaming temperature of the material to be tested. This defoaming temperature has been found to correlate well with the defoaming ability of the material in actual ink removal treatments.

As mentioned above, the surfactants used in the present invention comprise an oxyethylene chain having an ether group at each end. The ether group at one end is aliphatic or alkylaromatic, and the ether group at the other end is an oxypropylene-25 chain, which in turn is either hydroxy-terminated or benzyl-ether-terminated. Depending on the desired balance of hydrophobic and hydrophilic properties, the second end group may be a benzyl ether group alone.

The typical structural formula of the preferred surfactant detergents of the invention is as follows:

R <cAr4-- £ -OC0H. 4 —- WC ,, Hc -) - Y

a 2 4 n 3 6 where a is 0 or 1,

Ar is aromatic, preferably the monocyclic residue R is an aliphatic group n has a value of about 3 to about 50 9 73015 m has a value of about 0 to 50 and Y is selected from hydroxy and benzyl and represents benzyl in the case where m = 0 .

The R group is typically saturated and contains at least 5 to 6 carbon atoms. When a = 0, R contains 6 to 24 carbon atoms, while a = 1, R normally contains up to 18 carbon atoms. Briefly, the R (Ar) group contains at least 6 aliphatic carbon atoms and up to a total of 24 carbon atoms. The above structural formula can be considered to include two main categories of surfactant detergents, namely (a) alkylene oxide adducts of alkylphenols, and (b) alkylene oxide adducts of higher aliphatic alcohols (containing more than 5 carbon atoms). To provide a hydrophilic segment in the nonionic molecule of a surfactant detergent, an alkylphenol or higher aliphatic alcohol is first condensed with ethylene oxide and then combined with a hydrophobic group, which may be either an oxypropylene chain (obtained by condensation with propylene oxide) or a benzyl group. an oxypropylene chain terminated by a benzyl group.

The oxyethylene chain is referred to as poly (ethylene oxide), and the polyoxypropylene chain is referred to as poly (propylene oxide), typically referring to an adjacent oxide.

Surfactant detergents containing alkylphenol-poly- (ethylene oxide) -poly- (propylene oxide) are generally prepared using alkylphenol-polyethylene oxides as starting materials. The alkylphenol-polyethylene oxides used as starting materials represent a previously known class of surfactant detergents that has long been used in a number of different industrial processes. The general structural formula of these known materials is

1 ^ 0) ~ (0Wn- 0H

10 7301 5 in which a straight-chain or branched monovalent alkyl radical of 6 to 18 carbon atoms, preferably 8 to 12 carbon atoms, and which can preferably be empirically represented by the formula CaH2a + 1 (preferably only one but also within the scope of the invention are compounds having several groups R 1), n has a value of 3 to 50, preferably 6 to 15, each (-O-C 2 H 4 -) unit is prepared by opening an ethyleneoxy-dir-ring / CH 2 - CH2 10 also known as oxirane. (Alkyl chains are sometimes described by the notation "C", where "a" is the number of carbon atoms in the chain, e.g. 2. This is to describe CaH2a + 1 in the case of saturated compounds). One particularly well-known class of alkylphenol-poly (ethylene oxide) compounds is nonylphenol-polyethylene oxide (NP-EO). Nonylphenol polyethylene oxides are characterized by an alkyl chain of nine carbon atoms attached to the aromatic core of the phenol, which is also attached (in the ortho, meta or para position to the alkyl chain 20) by a hydroxy-terminated polyether chain having 1 to 40 ethylene oxide units, i.e. is worth 1 ... 40. Although such conventional products NP-EO can be synthetically prepared as fairly pure fractions with a fairly defined value of n, these products are generally sold as molecular mixtures with a number n of several different values. These mixtures are characterized by their mean n mean, so the usual material is NP-EOg which means that there is an average of 9.5 ethylene oxide units (moles) per nonylphenol core (n = 9.5). 30 Nonylphenol polyethylene oxides with average values in the range of 1 to 40 are available from a number of companies, such as GAF Company under the trade mark "Igepal", Rohm & Haas Company under the trade mark "Triton" and Jefferson Chemical Company under the trade mark " Surfonic ".

11 7301 5

According to the invention, alkylphenol-polyethylene oxides are used which have a number of propylene oxide units (-OCgHg-) or a benzyl group attached to the distal end of the polyethylene oxide chain, the polypropylene oxide chain (if used) preferably being hydroxy-terminated (-OH) or benzyl-C-terminal to obtain the following structure

'OC2' s>; - <0C3H6> -Y

wherein Y is as defined above, Y is selected from hydroxy or benzyl, n is as defined above and m is 0 to 50, preferably about 4 to about 48 (Y is benzyl when m = 0).

It has been found necessary that the polyethylene oxide segment be located adjacent to the hydrophobic portion of the molecule (i.e., adjacent to the alkylphenoxy portion or the higher molecular weight alcohol portion) in order to achieve the preferred results of this invention.

Usually the number m has a non-zero value. When m is not zero but Y is hydroxyl, there are preferably enough propylene oxide units in the relatively hydrophobic segment represented by the group (OCgHg) m to contribute at least as much to the hydrophobic nature of the molecule as the benzyl group does. It has also been found that the replacement of the hydroxyl group terminating the oxypropylene chain with various other end groups such as benzyl has not reduced the utility of the alkylphenol-poly- (ethylene oxide) -poly- (propylene oxide) compounds of the invention. However, if the ratio of the units of propylene oxide (PO) to ethylene oxide (E0) is sufficiently high, Y is usually best a hydroxyl group.

The hydroxy-terminated nonylphenol-polyethylene oxide propylene oxides (ΝΡ-Ε0-Ρ0-0Η) of the invention are prepared by applying the methods 12,701,5 known in the art. Thus, the product ΝΡ-Ε0-Ρ0-0Η can be prepared by reacting NP-EO (e.g. "Igepal" or "Triton") with propylene oxide at e.g. 100-150 ° C and a pressure of about 100-400 kPa, wherein a basic catalyst, e.g. potassium hydroxide, is present. U.S. Patent 3,021,372 (Dupre et al.) Specifically describes the preparation of preferred hydroxy-terminated octylphenol and nonylphenol-polyethylene oxide-polypropylene oxides, and the teachings of this patent are incorporated herein by reference. In general, the catalyst used in the preparation of the NP-EO material is not removed before the addition of the PO segments (thus, the non-neutralized compound NP-EO should be used).

Another type of surfactant detergent used in the practice of the invention is the addition products of higher molecular weight alcohols, i.e. long chain alcohols, with hydroxy-terminated or benzyl-terminated ethylene oxide-propylene segment oxide, whereby the polyethylene oxide moiety 20 By "higher molecular weight" or "long chain" alcohols is meant herein unbranched or branched, saturated or unsaturated, primary or secondary alcohols having from 6 to about 24 carbon atoms and generally having a molecular weight in the range of about 75 to 300 . These materials are also sometimes called fatty alcohols. Nonionic surfactant detergents prepared from higher molecular weight alcohols can be represented by the following formula: wherein R 2 is a straight or branched saturated or unsaturated monovalent aliphatic chain of about 6 ... about 24 (preferably 10 to 18) carbon atoms, Y is selected from hydroxy or benzyl, n is about 13 7 3 01 5 3 to 50 (preferably 6 to 15), m is about 0 .. about 50 (preferably about 4 to about 48), wherein Y is benzyl when m = 0.

Preferably, the hydroxy-terminated EO-PO adducts of higher molecular weight alcohols can be prepared by adding EO-PO polyether segments to saturated or unsaturated alcohols having the desired carbon backbone. In this case, either synthetic alcohols (i.e., alcohols prepared by known Ziegler or carbonylation processes) or alcohols which are generally prepared by reducing naturally occurring fatty acids to fatty alcohols can be used. The fatty acids used as starting materials can be obtained by extraction from natural sources such as coconut oil, palm oil, tallow, lard and tall oil. The length and structure of the carbon chain of the alcohol are determined by the nature of the fatty acids used as starting materials or the conditions used in their synthesis. Particularly desired alcohol structures can, of course, also be prepared from natural sources by distillation or the like, or by applying the above-mentioned synthetic methods and then distilling. Particularly preferred alcohol EO-PO adducts according to the invention are prepared synthetically from a mixture of an alcohol having 16 carbon atoms and an alcohol having 18 carbon atoms to which an E05 (PO)? 3-OH-hydroxy-terminated polyether chain is attached.

As already mentioned above, the nonionic surfactants of the invention are usually hydroxy-terminated or benzyl-terminated. The hydroxy-terminated product is, of course, obtained in the case where propylene oxide units are added to the polyethylene oxide chain (which is also hydroxy-terminated). The benzyl group can be terminated in the structure by reacting benzyl chloride with a hydroxy-terminated alkylphenol-EO-PO material after reacting the NP-EO-PO-OH material with sodium metal. This can usually be done in a temperature range of about 93 to 150 ° C.

The balance of hydrophilic and hydrophobic properties of the surfactant detergents preferably used according to the invention can be roughly determined by the weight ratio of the hydrophilic moiety to the hydrophobic moiety according to the structural formula. In the case where the surfactant detergent molecule contains both E0 and PO units, the E0 / PO ratio is the main factor determining the balance between the hydrophobic and hydrophilic properties of any given R (Ar) end group. If no PO is present (m = 0), the size of the oxyethylene chain (number n value) relative to the hydrophobic contribution of the benzyl ether at the terminal position is a major factor in this equilibrium, even when the R (Ar) group is determined.

CL

In cases where the E0 / PO ratio is the main factor in determining the balance of hydrophobic and hydrophilic properties, the typical ratios of E0 to PO (i.e., ratios n: m) are in the range of about 1: 4 to 4: 1. Lower "defoaming heat-20 states" typically occur when the E0 / PO0 ratio is less than 1: 1, and especially when there are at least about 6 propylene oxide units. The selection of an appropriate balance of hydrophobic and hydrophilic properties is preferably accomplished by resorting to the aforementioned "foam decomposition temperature" rather than comparing either cloud points or theoretically calculated HLB values. As already mentioned above, defoaming temperatures are considered to be a particularly advantageous indicator when it is desired to achieve the desired balance between water solubility or dispersibility, defoaming properties and ink removal properties of the invention. Other conditions for selecting preferred nonionic surfactant detergents relate to refiberization and / or ink removal temperatures, ink removal efficiency determined by standard fiber whiteness tests, or other similar practical considerations.

15 7301 5

In the following, a method for selecting a suitable nonionic surfactant detergent will be described with reference to the accompanying figures.

Figure 1 summarizes the properties of hydroxy-terminated nonylphenol-EO-PO surfactants in terms of foam decomposition temperature. The vertical axis of Figure 1 shows the number of moles of ethylene oxide condensate (-C ^ P ^ -), and the horizontal axis shows the number of moles of propylene oxide condensate (-OC ^ Hg) per mole of nonylphenol-10 moiety (CgH ^ g-CgH ^ -). The lines of the drawing, which generally radiate from the origin (defoaming isotherm), combine the various combinations of E0 and PO to give the indicated defoaming temperature and thus give the EO-PO combination with little or no foaming.

In the practice of the invention, the deinking treatment is initiated and continued therefrom until equilibrium is reached (the treatment is continued long enough to eliminate larger temperature fluctuations). When this equilibrium state is reached, the temperature profile of the entire deinking treatment is determined (i.e., the temperature variation of the deinking medium along the various stages of the deinking treatment line). In general, there is the greatest risk of foaming in cases where washing, filtration, or mixing, etc., takes place at the lowest temperature. When selecting the surfactant to be used, the lowest treatment temperature at which the isotherm is selected from Figure 1 must be determined.

If, for example, the lowest temperature during the entire ink removal treatment is about 15 ° C, it can be assumed that either NP-EDg g-30 po -OH ta-i NP-EOg gPC ^ -OH gives an acceptably low foaming, as shown by the defoaming test.

Figure 2 shows defoaming isotherms determined for the higher molecular weight alcohol -ED-PO-OH surfactants described herein. According to Figure 2, the specially tested surfactant 16 7301 5 contains a mixture of alcohols having 10 carbon atoms, 12 carbon atoms and 14 carbon atoms (i.e., about 28 ... 34¾ ^, 35 ... 41% 3a 27. .. 33% C1Q) to which 5 polyether chains of the indicated composition have been attached. Similar isotherms are obtained with the EO-PO adducts of C16 / C18_ (about 60% C16 ', 40% C18 ^' C14 / C18 and C12 / C18 alcohols. Theoretically, it could be assumed that similar defoaming properties could be achieved with all surfactant detergents. , the use of which is explained here.

Thus, in applying the deinking method of the invention, optimization could be achieved for each class of surfactant detergents described herein and the compounds contained therein. These isotherms can be determined by measuring the defoaming temperature (as described above) for different combinations of E0 and PO units and the higher alcohol or alkylphenol used in each case.

In particular, the choice of defoaming temperature must be considered in connection with the temperature at which the washing-type ink removal treatment will be performed. In a conventional deinking treatment in which water is used as the deinking medium either alone or in combination with surfactants and / or defoamers typically used, the water mass or slurry of waste fibers must be heated to e.g. 70 ° C in the re-fiberization step. The fibrous sludge tends to cool as it is treated. It is already known that as the slurry cools, surfactant detergents usually tend to promote foaming. One technique used to reduce foam is to heat the aqueous medium above the temperature at which the surfactant used in each case causes some loss of foam. (According to the applicant's known findings, the loss of foam 35 is most likely to occur at temperatures above the heat dissipation temperature). In a typical prior art use, the slurry is heated by causing steam to flow through the slurry as this slurry travels along the ink removal treatment line.

According to the invention, it is possible to use these typical temperatures according to the prior art (which can, for example, be as high as 85 ° C), but lower re-fiberization temperatures are much more advantageously used, these temperatures being in the range from 30 ° to 60 ° C.

It has been found that once the properties of a particular deinking treatment have been determined, the surfactant detergent can be selected so that foaming can be reduced or even avoided altogether. This means that since the temperature profile of a particular deinking process changes during the year (usually the temperature of wash water simply pumped from an outdoor water source can vary several degrees from the hottest time of summer to the coldest months of winter), it may be advantageous to choose a surfactant with another 20 hydrophobic detergent. balance of hydrophilic properties (e.g. E0 / PO0 or EO / benzyl ratio) to reduce foaming. That is, the defoaming temperature will typically be adjusted to the lower end of the refiberization temperature range so that the temperature of the aqueous medium used for the refiberization is generally higher than the defoaming temperature, even after the refractory winter temperature. Conversely, the potential advantage of the relatively high summer temperature of an external water source can be exploited by selecting another surfactant detergent.

The application of the method according to the invention will be explained in more detail below. As already mentioned above, the re-fiberization of waste fibers is an important step in a typical detergent removal treatment. According to the invention, the refiberization 18 7301 5 can be carried out without the presence of a surfactant detergent, so that a person skilled in the art can transfer the addition of this detergent to a later stage of the treatment, e.g. However, the surfactant detergents of the Kek-5 invention may also be present (and are preferably present) during re-fiberization, thereby achieving significant chemical separation of the ink from the waste fibers during this key step.

The aqueous medium is preferably mixed during re-fiberization. The pH of the medium can vary within wide limits (to which both acidic and basic pH values fall) because the surfactant detergents used in this treatment are effective throughout this wide range of pH values. The consistency (i.e., solids content) during refiberization is the same as in any typical pulp. The consistencies of the pulps are usually well below 10% by weight to avoid excessive difficulty in mixing, pumping or otherwise handling the fibrous slurry 20 or pulp. On the other hand, a consistency of less than about 2% by weight would result in the use of very large amounts of water in the treatment. In the initial stages of the re-fiberization stage, typical consistencies are in the range of about 3 ...

25 about 6 or 7% cellulose fibers (calculated on the total weight of pulp, additives, etc.). Once the initial ink removal has been completed, the re-fiberized waste fibers can preferably be diluted to a 3% lower consistency to facilitate separation of the relatively ink-free fibers from the aqueous medium of slurry 30, which now contains contaminants in a more or less evenly distributed manner.

The pH of the re-fiberization medium can advantageously be adjusted, e.g. by adding 1 to 3% by weight of sodium hydroxide, based on the weight of the cellulose-35 fibers in the re-fiberization medium. Such an amount of added sodium hydroxide is typical of a pulp having a consistency of * +; .. 6% and means about 9 to 27 kg of sodium hydroxide per ton of fiber. __ 7301 5

In the re-fiberization step, any commercially available commonly used equipment can be used to re-fiberize waste fibers (e.g., 5 equipment of the "Hydrapulper" type).

As mentioned above, as a result of the typical application of the re-fiberization step according to the invention, it is achieved that contaminants, in particular zinc ink, are separated from the cellulose fibers of the re-fiberized pulp at least to some extent. Since the contaminants are dispersed and / or dissolved and / or suspended throughout the aqueous medium used for re-defibering, this aqueous medium should preferably be separated from the fibers so that the contaminants will have less tendency to settle on the surfaces of the fibers. The most preferred separation method is screening, i.e., applying the pulp to a porous surface capable of retaining the fibers, while the aqueous medium flows through the holes in that surface. The fibers left on the sieve can be reslurried in water and sieved.

In this way, relatively pure or relatively low-contaminant fibers can be counted through as many separation steps as desired. This method of removing contaminants is sometimes referred to as "washing," and this method typically takes its name from the "wash" -type deinking-25 treatment. No foaming steps or foaming are required during washing. By using the nonionic surfactant detergents described herein, conventional washing machinery can be used, and thus the costs and disadvantages of flotation-type equipment can be avoided. In addition, the applicability of conventional washing equipment 30 expands because the invention allows the removal of contaminants from many different types of waste fibers. Among the conventional types of washing machines suitable for use according to the invention, mention may be made of the "Lancaster" washing machine, the wear-type washing machine and the thickener type washing machine, all of which are known in the art.

so 7301 5

In an optional step used in accordance with the invention, the refiberized fibers can be partially cleaned of foreign matter such as dirt, staples, paper-zinc, etc. This type of foreign matter can be removed from the fibers using a screen set with ever smaller mesh sizes. Centrifugal cleaners have also been used to remove this type of foreign material, as dirt, staples, paper bristles, and other foreign materials typically present in the treatment of this type of waste fiber often differ significantly in density from cellulose and its normal contaminants.

After the foreign materials have optionally been removed in this way, the re-fiberized, purified pulp can optionally be either concentrated or diluted, i.e. water can either be added or removed. Concentration of the pulp, i.e. thickening, can be done by applying various methods, e.g. filtration under reduced pressure or removal of water by means of a thickener.

During one or more of the above-mentioned washing steps, the separation of the fibers from the aqueous medium can be facilitated by applying vacuum, gravity, centrifugal filtration or other thickening methods. Of the washing machines described above, an expansive type washing machine is preferably used, since thus the lowest capital investment per unit of decontaminated fibers is achieved.

After the desired number of washing steps have been performed, the contaminated cellulosic fibers can be further treated (e.g., by bleaching) to improve color or other properties. Such additional treatments are optional within the scope of the invention.

When applying conventional deinking treatments, there is a tendency for foam to develop in many of the aforementioned deinking steps, e.g., the washing steps. In the practice of the invention, the excessive foaming has been considerably reduced, unless it has been completely removed, but still nothing has been lost in the decontamination efficiency. Reducing foaming increases the efficiency of the processing machinery (especially its processing capacity) because the volume processed by the processing machinery is not reduced by any larger proportion of foam. In addition, reducing foaming shortens the downtime of the machinery due to over-foaming into the receiving tanks. The reduction of foaming in the application of the invention also seeks to improve the efficiency of the wash-type ink removal treatment in terms of cost.

When the invention is applied on a paper mill scale, a suitable amount of waste fibers from which ink must be removed is fed to a re-fiberization device (e.g. "Hydrapulper" type-15) and a consistency of 6% is achieved, i.e. 6% fibers and 94% water mixed with these waste fibers. heated to 25 ... 85 ° C. In addition, the nonionic surfactant detergents according to the invention are added in an amount of 0.1 to 1% by weight, based on the total weight of the waste fibers.

Optionally, depending on the particular conditions applied in each case, a base such as sodium hydroxide, sodium silicate, sodium carbonate, sodium phosphate, etc. may be added up to 3% by weight of the waste fibers (optionally, acids, e.g. sulfuric acid) may be used in the refiber solution. Other processing aids may also be added, e.g. talc or water improvers which do not adversely affect the treatment according to the invention. These substances are usually added before re-fiberization. At this stage, the whole pulp is preferably mixed vigorously for 30 to 180 minutes, for example, so that the non-cellulosic materials are more easily separated from the waste fibers and the waste fibers are better separated. This mixing can be achieved, for example, in abrasive or non-abrasive fibers, and either batch or continuous treatment can be applied.

After this preferred vigorous mixing, a suspension of re-fiberized cellulosic fibers is formed, in which non-cellulosic materials such as inks, binders, etc. are suspended, which materials can be easily washed out of the cellulosic fiber suspension. This suspension contains the nonionic surfactants according to the invention, e.g. nonylphenol- (E0) g g-CPO) -OH, as well as optionally other additives.

The refiberized, partially refined fibers are then subjected to one or more washing steps, as described above, whereby the fibers can be washed in a washing machine with a nitrogen consumable, a "Lancaster" washing machine, etc. The decontaminated waste fibers thus obtained are suitable for use in a conventional paper machine, e.g. flat screening machine.

The following examples illustrate the principles of the invention and its application.

Example 1 This example illustrates the preparation of a hydroxy-terminated nonylphenol (E0) g 5_ (PO) 21+ detergent.

A 7,500 kg nonylphenol is charged to a cleanable 7500 liter stainless steel pressure reactor with stirring means and temperature control devices, which is stirred for 10 minutes while bubbling nitrogen through it. 20 kg of potassium hydroxide are added to the nonylphenol, the reaction mixture is blown several times, e.g. 3 times, clean with nitrogen, and a small excess of nitrogen is left in the reactor. At this point, the contents of the reactor are heated to about 110 ° C, at which temperature the reactor is again blown clean with dry nitrogen so that the excess pressure of nitrogen remains. Heating of the reaction components is continued to about 120 ° C, and at this point the heating is stopped and the reactor is blown several times clean, as described above. 1390 kg of ethylene oxide are then added to the reactor at a rate of 19 to 45 liters per minute, the addition of ethylene oxide and the heating or cooling of the reactor being controlled so that the reaction medium remains at 143 DEG-5.5 DEG C. During the addition of ethylene oxide, the reactor pressure must be kept below 400 kPa. Ethylene oxide is added to the point where the cloud point of nonylphenol-5 ethylene oxide is present in a 1% aqueous solution (i.e., a 1% aqueous solution of material where the material begins to precipitate from solution, as seen from turbidity) at a temperature in the range of 53-58 ° C. After the addition of EO is complete, the mixture is allowed to react at 143-5.5 at 10 ° C for 20 minutes. P0 is then added until the cloud point in the 2O% butyl carbinol solution of the EO-PO adduct is 48-50 ° C. As the addition of PO continues, the cloud point of the adduct further decreases.

After the addition of PO, the finished product is cooled to 79 ° C and 20.4 kg of glacial acetic acid are added to neutralize the potassium hydroxide, after which the product is stirred for a further 30 minutes. Thus, the synthesis of nonylphenol-EO-PO is completed.

The nonylphenol (E0) g 2 product was used to synthesize the surfactant detergents of the invention with 0, 6, 12, 18 and 24 moles of propylene oxide. These surfactant detergents were then used to determine their effectiveness in washing cotton and to determine the whiteness of hand-made ink sheets made from office paper pulp, as described in Example 2. The results of this inspection are shown in Table I. Surprisingly, the quality of the cotton wash was found to deteriorate with increasing PO amounts, while the whiteness of the handmade sheet was found to improve (both measured as described above and by measuring deviations from the standard value, i.e. delta values). In fact, the ability of the surfactant detergents of the invention to remove ink was found to be the opposite of what could be predicted from their effectiveness as a cotton detergent.

,, 7301 5 24

Table I

Whiteness Cotton wash- PO moles Reflection- Delta- Reflection quantity_meter_value_meter _ 0 77.5 13.8 55 56 78 13.6 47 12 80.5 11.2 41 18 80.5 11.2 38 24 84 7, 4 35

The effectiveness as a cotton detergent is determined by the whiteness of the washed fabric 10.

Example 2 This example illustrates the preparation of handmade sheets for testing surfactants in a laboratory.

15 g of pulp from which the ink must be removed (e.g. business book-15 holding paper) is placed in a "Waring" mixer, to which 375 ml of water is also added, followed by mixing for one minute. The contents of the stirrer are then poured into a laboratory beaker and the pH of the solution is adjusted to 10-11 by adding about 6 or 0.6 g of sodium hydroxide pellets. Then 0.1 g of test surfactant is added. The whole mixture is then heated to the desired ink removal temperature, e.g. about 65 ° C, with constant stirring, and the temperature is maintained at this value for at least 10 minutes.

The heated mixture is then diluted with water to a volume of about 3 L and poured onto a 40 mesh (US standard screen size) screen held at an angle of about 37 ° to the horizontal. This simulates a consumable type of washing machine and concentrates the fibers while washing away the ink particles.

30 Dilution and washing are repeated to produce ink-free waste fibers.

25 7 30 1 5 The fibers cleaned of the ink can then be bleached by adding a liquid bleach solution (eg "Purex") and the pH of the solution can be adjusted to 9 ... 11 by adding 3 pieces of sodium hydroxide pellets.

5 Finally, sheets are removed from the deinked fibers by hand, the whiteness of which is measured as described above. The sheets are made by hand using one of the methods commonly used in the United States, e.g., the method described in 10 TAPPI T2-5 OS-71, etc. Generally, four handmade sheets are made by diluting the washed ink-cleaned fibers with 3 liters of water, such as explained above.

Example 3 This example illustrates the preparation of a benzyl-terminated higher molecular weight alcohol and polyethylene oxide adduct.

The reactor described in Example 1 is charged with a mixture of 23% by weight (of the finished mixture) of Alfol, TC / alcohol, 0.23% by weight of potassium hydroxide and 0.23% by weight of potassium hydroxide, after which the reactor is heated to 115 to 121%. About 77% by weight of ethylene oxide is added to the heated alcohol, the reactor temperature is allowed to rise to 160 ° C and the reactor pressure is kept below 400 kPa until the total amount of ethylene oxide per mole of alcohol is added.

A second reactor similar to that described in Example 1, except that it has an air barrier suitable for the addition of sodium metal, is charged with 86% of the above-mentioned alcohol EO product, 12% of sodium metal and 12% by weight of benzyl chloride. Sodium metal is added after the alcohol EO product has been heated to about 113 ° C and the reactor has been purged several times with nitrogen. Metallic Sodium is added via an airlock 26 7 30 1 5 in small portions so that the addition is completed within about 2 hours. When metallic sodium is added to the above mixture, hydrogen gas is evolved, so it is important that the system is regularly blown completely clean with nitrogen.

After the addition of sodium, the temperature of the mixture is maintained at 113 ° C for about 2 hours, during which time the system is repeatedly blown clean to remove any hydrogen evolved.

After about 2 hours, the system is blown clean with 10 air so that the hydrogen is completely removed.

At this point, benzyl chloride is added, and the reaction mixture is cooled to maintain a temperature of 115-121 ° C. The rate of addition of benzyl chloride can be adjusted so that the temperature of the reaction mixture remains within the desired range of 115 to 151 ° C. After the addition of benzyl chloride, the sodium chloride formed in the reaction must be removed, which can be done by cooling the reaction mixture 9 to 3-110 ° C and extracting the sodium chloride with water. To remove any sodium chloride still present in the product, the product must be heated to 20 135 ° C and washed again with water. Finally, a filtration aid, e.g. diatomaceous earth, is added to the product, after which the product is filtered to produce a benzyl-terminated alcohol EO material.

The invention may be modified and modified in many ways by those skilled in the art without departing from the spirit and spirit thereof, and the invention is not limited to the illustrative embodiments and examples described herein.

Claims (22)

A washing method for obtaining substantially reclaimed recycled fibers from relatively contaminated recycled fibers, in which process a) suspends the relatively contaminated recycled fibers in a water medium comprising a surfactant so that the contaminants in the relatively recycled recycled fibers disperse through water. and b) substantially separating the substantially obtained pollutant-liberated recycled fibers from the resulting impurities containing the aqueous medium, characterized in that the fibers are suspended in the aqueous medium which is presently less than 1% by weight of the contaminated fibers by a single foam surface of a single foam surface. , which consists essentially of the product R- (Ar) -fOC2H4) rn- (OC3H6) nY where R represents a monovalent higher aliphatic group, A represents an aromatic residue, - (OC2H4) m- is a poly (ethylene oxide) chain - ( OC3Hg) n- is a poly (propylene oxide) chain m is about 6 ... 15, n is about 12 ... 48, m: n is less than 1, and Y is hydroxyl or benzyl wherein the surfactant is selected such that it reduces or prevents foam formation through at the coldest temperature the water medium is subjected to in the process. Process according to Claim 1, characterized in that the temperature of the aqueous medium is about 25 ... 85 ° C. Process according to claim 1, characterized in that the water mixture is heated to a temperature within the range of about 25 ... 55 ° C. Process according to claim 1, characterized in that the mixture is heated to a temperature within the range of about 25 ... 37 ° C. 5. A process according to claim 1, characterized in that the separation step further comprises mixing the fibers while heated. 6. A method according to claim 5, characterized in that the mixing takes place with the aid of a defibrillator operating with or without friction. Process according to Claim 1, characterized in that Y is hydroxyl. Method according to claim 1, characterized in that R contains 6 ... 24, e.g. about 9 ... about 15 carbon atoms. 9. A process according to claim 1 for the production of decolorized recycled fibers via an intermediate suspension of recycled fibers having mixed ink particles which can be readily isolated from the suspension by washing, characterized in that the ink particles and the recycled fibers are separated to obtain the suspension by heating the fibers to a temperature. 25 ° C and 85 ° C in an aqueous medium containing less than 1% by weight of the return fibers weight of said single non-ionic surfactant, and isolating the ink particles and surfactant from the return fibers by washing away the particles from the suspension to obtain dyed fibers. Process according to claim 9, characterized in that the water mixture is heated to a temperature within the range of about 50 ... 55 ° C. 34 7301 5 11. A process according to claim 9, characterized in that the water mixture is heated to a temperature within the range of about 25 ... 37 ° C. Process according to claim 9, characterized in that R is a monovalent alkyl group selected from octyl, nonyl and dodecyl. Process according to Claim 9, characterized in that the water mixture is alkaline. A process according to claim 13, characterized in that the alkalinity depends on the presence of a base selected from alkali metal hydroxides, silicates, carbonates or phosphates. 15. A process according to claim 9, characterized in that the water mixture is acidic. 16. A method according to claim 9, characterized in that the insulation is effected by means of vacuum, under the influence of gravity or by centrifuge filtration or concentration of the cellulose fibers. 17. A method according to claim 9, characterized in that the insulation step comprises washing the ink particles from the fibers by letting the slurry run downwards along a sloping washing device. The method of claim 1, for obtaining substantially decolorized recycled fibers from ink-containing recycled fibers, comprising the steps of a) re-etching the recycled recycled fibers into an ether-fibrous water medium containing the surfactant, wherein the ink the ink-containing recycled fibers are evenly distributed in the ether-fiber water medium during the ether-fiber, and b) deposits the substantially substantially decolorized recycled fibers on a permeable surface and allows the formed ink-containing ether-fiber-water medium to flow through the heels through the heel. , characterized in that the ether fiber is carried out in an aqueous medium containing an antifoaming amount, i.e. less than 1 wt.% by weight of the ink-containing recycled fibers of a single foam-preventing, nonionic surfactant, consisting mainly of the product R- (Ar) - (OC2H4) m- (OC3H6) new where R is a monovalent higher aliphatic group, Ar is a divalent aromatic residue, is a poly (ethylene oxide) chain, - (OC3H5) n- is a poly (propylene oxide) chain, m is about 6 ... 15, n is about 12 ... 48 , the m is less than about 1, and Y is hydroxyl or benzyl ether, the hydrogen-containing etheric fiber medium being above 25 ° C, but falling below about 60 ° C before the etheric fiber is complete. 19. A process according to claim 18, characterized in that the nonionic surfactant has the structure (O-10C2H4) m- (OC3H6) nY, wherein R is a monovalent alkyl chain of about 6 ... 18 carbon atoms, - (OC2H4) m- is a poly (ethylene oxide) chain, - (OC3H6) n "is a poly (propylene oxide) chain, m has a value from about 6 tili to 15, and n has a value from about 12 tili about 48. m is below about 1, and