JP3222462B2 - Processing of absorbent physiological paper products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the treatment of absorbent sanitary paper products in a manner that provides materials that can be recycled for subsequent use. As used herein, absorbent sanitary paper products include disposable diapers, incontinence products, feminine hygiene products, bed pads and other related absorbent and adsorptive products.

Absorbent sanitary paper products typically comprise (i) a nonwoven sheet made from a liquid permeable material, such as a liquid permeable membrane made from polypropylene, polyethylene, or a nonwoven sheet made from cotton or rayon. A product, (ii) a liquid-impermeable backsheet made of, for example, polyethylene, polypropylene, starch-based degradable plastic film, woven fabric or rubber, and (iii) an air-containing, commonly called air felt. (Laid)
It consists of an absorbent or absorbent core of wood pulp fluff and / or synthetic pulp containing polypropylene or polyethylene filaments which may be bonded or unbonded hemp or other adsorbent fibrous material.
The core is typically creped of wet strength tissue paper or a material having similar properties (cr
eped) Wrapped or encased in a mantle. The wrap over the core may or may not be absorbable, biodegradable, odor degradable, or degradable or soluble by other means. This core also usually
It includes a superabsorbent polymer (SAP) material, which can be synthetic, typically in particulate, fibrous or laminated form, and which binds to water, urine or other bodily fluids, or Polyacrylates, polyacrylamides, cross-linked starches, or other hydrophilic components that have the power to retain them without substantial release or discharge from the absorbing moiety. Diapers and incontinence products
Typically, a pressure sensitive adhesive or similar closing mechanism for a re-securable tape tab is utilized. Women's hygiene pads and incontinence products often use pressure sensitive adhesives for adhesive lines that attach the pad or liner to the user's underwear. Diapers and incontinence products typically utilize a resilient, polyurethane, pleated and coherent or adhesive to create a tight mounting cuff around the leg and waist opening to provide a more leaktight fit.

Absorbent sanitary paper products are usually disposed of by incineration or into landfill sites together with refuse generated by households, institutions and hotels. Incineration tends to result in air or other pollution.

Thus, the consequences of the convenience or necessity of using absorbent paper products include problems with the disposal of such products. In addition, the use of either incineration or landfill disposal is not the recycling of some or all of those components to the same or other end use, but the loss or destruction of components of the absorbent sanitary paper product. As a result. This disposal problem is becoming an increasing concern with respect to environmental and governmental authorities, and there is a need for means for effective disposal and utilization of used absorbent sanitary paper products.

A continuous batch type washing machine for washing fabric goods is disclosed in U.S. Patent No. 4,485,509 issued December 4, 1984 by NLPellerin et al. And issued December 29, 1981 by JM Katzfey. Canadian Patent No. 1,115,
No. 075. U.S. Patent No. 4,162,019 to CGJoa, issued July 24, 1979, describes cutting a sanitary article to expose the filler and recovering the filler using subsequent suction means. The plastic backing film is discarded. B. Steffe issued on February 19, 1985
US Patent No. 4,500,040 to NS describes shredding of a sanitary article and subsequent recovery of the filler using suction means. US Patent No. 4,303, issued December 1, 1981,
In 501, Steffens describes the use of a sieve to collect lint from discarded sanitary articles and cut absorbent material. In U.S. Pat. No. 4,592,115 issued June 3, 1986, S. Holmstrom discloses an apparatus and method for separating cellulosic fluff fibers from waste fibrous material using an open cylindrical separator. Is disclosed. It is understood that the methods described above are directed to dry separation and recovery of components of the rejected product, rather than recovery of components from the product used by the consumer. RR
Albers discloses U.S. Patent No. 4,39, issued July 5,1983.
No. 1,108 discloses a drum for a continuously operated laundry processing machine.

The absorbent physiological paper product can be treated in a manner that allows for the recovery of some or all components of such a product in a manner that facilitates recycling or other use of these components. Here's what you can do.

Accordingly, the present invention is directed to a method for the treatment of such absorbent sanitary paper products to separate them into their components in a form suitable for recycling or reuse, comprising the steps of: Comprises plastic, cellulose and superabsorbent polymer moieties, the method comprising the steps of: (a) subjecting the product to non-destructive separation into its components and to assist in separating particulate and / or soluble materials; Treating the product in at least one bath of an aqueous solution with: and (b) dividing the product into at least two parts, one consisting essentially of a soluble material and the other comprising a plastic; Subsequently separating a part consisting essentially of at least one of the cellulose and superabsorbent polymer moieties.

In a preferred embodiment of the method according to the invention, in step (b) the product is divided into at least two parts,
That is, one consists essentially of particulate and soluble materials and the other separates into parts consisting essentially of plastic parts, and separates the superabsorbent polymer and cellulose parts in particulate form.

The present invention further provides the method of the present invention wherein (c) at least one portion from step (b) comprises:
Treating with at least one aqueous washing solution and with at least one aqueous solution of at least one of a bleach, a brightener and an antimicrobial; and (d) the plastic, cellulose and superabsorbent thus treated. Recovering a separate stream of the polymer portion from the method.

In a preferred embodiment of the method of the present invention, the conditions that aid the separation include the temperature of operation of the bath, the composition of the bath, and mechanical measures.

In another embodiment, the absorbent physiological paper product comprises a superabsorbent polymer, and the superabsorbent polymer is separated in particulate form.

In another embodiment, the superabsorbent polymer in particulate form is a crosslinked superabsorbent polymer.

In another embodiment, the method is a continuous batch method.

The present invention combines a superabsorbent polymer with an aqueous solution of at least one water-soluble compound of an alkali metal, alkaline earth metal, aluminum, copper (II), iron (III) and zinc, preferably with an aqueous solution of aluminum. There is further provided a method for treatment of a superabsorbent polymer comprising steps.

In a preferred embodiment of this method, the superabsorbent polymer is an aqueous or alkaline earth metal water-soluble compound and at least one water-soluble compound of aluminum, copper (II), iron (III) and zinc. Treat with solution.

The invention also relates to water-soluble compounds of at least one of alkali metals, alkaline earth metals, aluminum, copper (II), iron (III) and zinc, in particular water-soluble compounds of alkali or alkaline earth metals, aluminum, copper ( II), iron (II
A cured superabsorbent polymer treated with a mixture of I) and at least one water soluble compound of zinc.

In a preferred embodiment of the superabsorbent polymer and method of treating the cured superabsorbent polymer, the polymer is an acrylic polymer.

In addition, the present invention is an apparatus for the treatment of an absorbent sanitary paper product for separating such components into suitable components for recycling or reuse, comprising: A) a rotatable and tiltable cylindrical drum having a first end and a second end and capable of holding an aqueous solution, wherein the drum is from a horizontal position, the second end being lower than the first end; Tiltable to a tilted position, the first end adapted to insert the product into the interior of the drum and retain the product therein, and the second end is adapted to receive the product from the drum; (B) means for rotating the drum in at least one of a horizontal and tilted position; and (c) means for tilting the drum from a horizontal position to a tilted position. An apparatus characterized by comprising: To.

In a preferred embodiment of the device of the invention, the drum has inlet means for the introduction of a fluid into the drum.

The method of the present invention relates to the treatment of absorbent sanitary paper products to recover these components for recycling or other reuse, as an alternative for incineration or landfill disposal of the absorbent sanitary paper products. In a preferred embodiment, the method of the present invention utilizes a rotating multi-shell drum, an example of which is described herein below. The method can also be used in tunnel washing machines or continuous batch types used in washing clothes, bedding and other articles in institutions, hospitals, hotels and other places where large quantities of dirty articles have to be washed. An apparatus of a type generally similar to the apparatus known as a washing machine may be used. Continuous batch type washing machines are based on two different modes of operation: one using an Archimedes screw to transfer clothing through the device and one using a modular system with mechanical means for clothing movement. Characterized.

The invention is described below with particular reference to the embodiments shown in the drawings. In the drawings, FIG. 1 is a schematic diagram of a continuous batch apparatus used in the method of the present invention, FIG. 2 is a drum for use in a preferred embodiment of the method of the present invention, and FIG. , An alternating tiltable drum for use in the method of the present invention.

In one embodiment of the invention, the method of the invention is operated in an apparatus having a plurality of modules, and the product is transferred between the modules. In another embodiment, the method may be operated by a single module, and the product is sequentially exposed to multiple solutions in the single module. In a preferred embodiment, the method operates by part of the method being performed in a first module and part of the method being operated in one or more subsequent, i.e., non-first, modules. Is done.

FIG. 1 relates to an embodiment in which the method of the invention is operated with a plurality of modules and generally represents a continuous batch apparatus 1 consisting of a series of modules indicated by I-XI.
Each module has a drum or basket mounted, in particular rotatably mounted, inside a bath of liquid, but only the module itself is shown diagrammatically in FIG. Module I is shown as being in an adjacent relationship with module II, and module II is now shown as being in an adjacent relationship with module III, and so on. Module I has an inlet 2 through which an absorbent sanitary paper product, often referred to herein as raw material, is supplied to module I. As shown, module I also has a water inlet 3, through which water can be supplied to module I. The direction of movement of the absorbent paper product or a portion thereof through modules IX is indicated by arrow 4.

Module I is made from module I
Connected to Module II so that it can pass through II. Module II is shown having a liquid outlet 5 connected to a settling tank 6. Other equipment can be used to effect separation or removal of material portions from the method of the present invention. The settling tank 6 is shown having a liquid outlet 7. Although module I is shown having a water inlet 3 and module II is shown having a liquid outlet 5, module I may also be connected to a settling tank, in particular a settling tank 6, It should be understood that there can be an outlet. Similarly, module II can have a water inlet. It is to be understood that the actual structure of the modules, liquid inlets and separation devices should reflect the nature of the product supplied to the method of the invention.

The drums (or baskets) in modules I and II preferably have an inner drum and an outer drum, and in a preferred embodiment, as shown in FIG. The drum in subsequent modules may be of similar construction, but in some cases may need to be adapted to facilitate the addition of solid materials, such as cellulosic materials.

The outer drum has relatively large holes, openings or pipe connections to allow movement of liquid therethrough.
The inner drum is formed with small holes that resemble a mesh sieve, and these holes will allow the passage of liquids and fine particulate matter, but will retain most of the product inside the inner drum . For example, a sieve having holes of 100-200 mesh may be used, which may vary depending on the mode of operation of the process of the invention. The device of the present invention is usually used for holes (about 9 mm in diameter) typically found in linen washing machines.
Would have substantially smaller holes. These holes may have various shapes. Sieves are materials that are inert with respect to the solution inside the module during operation, for example with respect to the livelihood or growth of bacteria, viruses or the like,
For example, they should be made of metal, especially stainless steel, plastic or fiberglass. The inner drum preferably cleans the holes under pressure in a continuous or intermittent manner with fresh or recycled water or other aqueous solution to remove material deposits from the holes and thus to close the sieve. It has a water spray suitable for maintaining high cleaning efficiency by eliminating and allowing free flow of liquid into and out of the inner drum. In modules I and II, such a wash
Helps remove particles and solubles, such as organics, from the feedstock.

Tunnel washing machines of the monoshell or Archimedes screw type can be used in processes of the type described herein, but are less preferred. Tunnel washing machines of the monoshell and Archimedes screw type tend to have a relatively small area for the netting, and this increases the ease of liquid flow into and out of such washing machine sections. Hinder. In addition, there is no absolute isolation of the device sections, and the device is also not easily adaptable to increasing or decreasing the number of device sections, and is not easily assembled or retrofitted. The modular system offers different speeds of rotation in different modules, isolation of processing steps,
It allows flexibility in the direction of rotation and in the transport of material, as well as flexibility in scale and process control. Existing double drum washing machines can be retrofitted to allow use in accordance with the preferred embodiments described herein.

A preferred example of a module I drum is shown in FIG. 2 and described later herein. The preferred use of this drum is also described.

FIG. 1 shows modules I and II as being of the same size as the remaining modules in the method of the present invention. However, the modules I and II can be of a different size than the remaining modules, in particular a few times the size of the remaining modules. Such oversize of modules I and II can be important with respect to the expansion of the feedstock containing SAP, as discussed herein, and the oversized module containing the feedstock, SA
This occurs during the processing of P and still provides the appropriate size load for subsequent modules. An alternative is to have module I or modules I and II in the form of a binary module, for example to have module I in the form of two modules, both modules I feeding into module II.

Module II is connected to module III, which is shown having a liquid outlet 8. In the embodiment shown, module IV has an inlet 9 for liquid shown as a detergent, although module III can have an inlet for liquid, and module
III has an outlet 8 for the liquid and the liquid in module IV moves to module III countercurrent to the feed stream.

As shown in FIG. 1, module V has neither an inlet nor an outlet for liquid, while module VI has an inlet 10 for liquid, shown as an aqueous solution of peroxide, preferably hydrogen peroxide. Have. However, other bleaching and / or
Alternatively, a microbial agent may be used. It is preferred not to use chlorine as a bleach for environmental reasons. The aqueous solution of peroxide moves countercurrently from module VI to outlet 8 in module III.

Module VII is shown having a water inlet 11 and a liquid outlet 12. Module VIII is shown having an inlet 13 and a liquid outlet 4 that may be used for acid solutions or for additional solution processing chemicals. Modules IX-XI are shown having water inlets 15, 16 and 20, respectively, and module XI has an outlet 17. Outlet 17 is shown moving to separator 18 having outlet 19. The separator 18 may in fact be a dewatering device, a dryer or an additional processing tank in addition to or instead of the separation equipment.

Each module preferably measures the amount of solid and / or dissolved material for the determination of temperature, the nature and concentration of the selected species, and in the various solutions used in the methods of the present invention. Has a sensor for measurement. In addition, these sensors are preferably connected to means for monitoring and controlling parameters important in the method of the invention.

An alternative and preferred device is shown, in part, in FIG. The device, shown generally as 100, has a drain opening 10 located at its lowest part.
It has an outer shell 101 with two. Inside the outer shell 101 is an inner basket 103. Inner basket 103
Is rotatable in either direction inside the outer shell 101. A plurality of agitators 104 and separation chambers 105 are arranged on the inner surface of the inner basket 103. Separation chamber 105
Comprises a sieve 106 and a roof portion 107, which may be a solid or a sieve. Inner basket at the end of the separation chamber 105 opposite the sieve 106
Within 103 is an orifice 108.

The drain opening 102 has two valves 109 and 110 for separation of liquid or material.

The inner basket 103 may have a constraining screen 111 on its inner surface at a location other than the separation chamber 105. Still further, the inner basket 103 may have a plurality of shark teeth or other cutter blades (not shown) on its inner surface for cutting material contained within the inner basket 103. Such blades may be formed from hardened stainless steel or carbide steel.

Another embodiment of the drum is shown in FIG. The drum 201 includes an outer drum 202 and an inner drum 203. The outer drum 202 is cylindrical in shape, but has a truncated base 204 having a valve 205 and an outlet pipe 206 at its lower end. The inner drum 203 has a perforated base 207, and the size of these holes depends on the size of the solid material to be passed through the holes. Inside the inner drum 203 but side by side with the holes 207 there are blades 208 of pulper 209. Blade 208 is driven by shaft 210 which is coupled to a motor (not shown).

The drum 201 can be tilted around the pivot 211,
The direction of the drum 201 is changed from the vertical shown in FIG. 3 to a non-vertical direction, in particular a horizontal direction.

In operation of the method of FIG. 1, the apparatus may have from one to eighteen or more modules in sequence, and the embodiment shown in FIG. The number of modules will depend in particular on the material to be processed in the method of the invention and the degree or type of processing required. A number of modules allow for the incorporation of additional processing steps, increase capacity, or allow for the division of one or more processing steps.

Absorbent physiological paper product or raw material is supplied to module I through inlet 2. In embodiments, the raw materials are bags, containers or containers containing such materials that have been conveniently included in the packaging of the absorbent sanitary paper product by their manufacturer for use in the disposal of used products. In other packaging materials.

The amount of feedstock is usually weighed prior to feeding to module I, and preferably is a water jet cutter,
Shred or reduce the size using a serrated or rotating knife, blade, shear, or other rotary cutting, chopping or granulating device. Water jet cutters are preferred. Shredding of the ingredients releases the ingredients, especially if it is packaged, taped or encased in bags, containers or other packaging materials, and covers soiled material such as feces, Or to facilitate purification of the raw material without the presence of folds or the like that trap liquids. Such covered soiled material or trapped liquid can contaminate the solution in subsequent modules. Shredding also reduces the size of plastic components, especially plastic sheets, in the raw material, but this otherwise covers the holes in the drum and prevents the exchange of liquids into and out of the drum. And shredding also reduces the likelihood of liquid contamination during subsequent steps in the method of the invention due to carryover to subsequent modules.

The method of the present invention is used in the manufacture of raw materials although it is operated under conditions that assist in the release of the raw materials, e.g., the thinning of the components of the raw materials and the melting of certain adhesives used in the manufacture of the raw materials. Certain possible adhesives and / or tabs, such as relatively high melting adhesives, rubber-based adhesives and welded parts, retain their identity in the method of the present invention. It is to be understood that there is a possibility. Shredding is an important preliminary step for raw materials with such adhesives and labels. Nevertheless, the manufacture of absorbent physiological paper products using an adhesive that is soluble under the conditions of the method of the present invention would be advantageous.

Water is supplied to module I through inlet 3. This water may be fresh water or it may be a stream discharged downstream of the module in the process of the invention. The liquids in Module I and Module II are maintained under conditions that aid in the removal of waste and other soluble or particulate matter from the raw materials, for example, under the use of detergents and under conditions that facilitate release of the raw materials. . The latter may also be achieved by the composition of the solutions used in modules I and II and the temperature of those solutions. The temperature is preferably maintained at a temperature not higher than about 70 ° C and especially not higher than about 68 ° C. Water temperatures as low as ambient temperature may be used. Higher temperatures may be used, but tend to cause possible deinking of the print on the raw material and / or cause excessive exfoliation of the product supplied to the process of the present invention, for example, The presence of ink, spandex, hot melt adhesive, crimped portions, tape labels or other small components can lead to difficulties in later processing or separation in the method of the present invention.

Absorbent physiological paper products are usually manufactured using superabsorbent polymers (SAP). Such polymers promote the wetting and wicking properties of the product, especially the cellulosic core normally present in the product, and increase the liquid holding capacity, especially of the absorbent sanitary product. Superabsorbent polymers tend to be acrylic polymers and starch-based polymers. At least the acrylic polymer is usually cross-linked in the manufacturing process and is discussed herein.
SAP bridging is another bridging that occurs in steps in embodiments of the method of the present invention.

As a result of SAP's inherent water absorbency, SAP tends to swell upon contact with water. The addition of SAP-containing feedstock to the process of the invention has a great influence on the capacity of the process of the invention, the operation of the process of the invention, the chemical consumption, and the type and quality of the product separated. The feedstock containing SAP swells to 2-5 or more times its dry (feed) capacity when introduced into the process of the present invention, and mechanical steps such as increasing module size, temperature, pressure And / or if no chemical steps are taken, it can cause significant capacity limitations. Chemical steps are performed in-situ SA in Modules I and II
Includes the addition of agents that reduce P crosslinking and / or SAP swelling and / or alter SAP particle shape and specific gravity. S
It is believed that the reduction or shrinkage of the swelling of the AP must be performed prior to or substantially simultaneously with the crosslinking of the SAP. Water-soluble alkali and alkaline earth metal compounds are believed to cause SAP shrinkage, while aluminum, copper,
Iron and zinc compounds are believed to cause crosslinking.
The treatment of SAP must be carried out in an acidic or substantially neutral solution, in particular at a pH of about 3 to 8, which limits the alkali and alkaline earth metal compounds that can be used . SAP, especially S produced from acrylic polymer
Examples of chemical compounds that can be added to the liquids in modules I and II, usually in the form of a mixture, to effect AP crosslinking include alkali metals, alkaline earth metals, aluminum, copper (II) , Iron (III) and zinc. Examples of such salts are calcium chloride, calcium nitrate, calcium sulfate, magnesium chloride, magnesium nitrate, magnesium sulfate, disodium phosphate, barium chloride, sodium carbonate and bicarbonate, trisodium phosphate, sodium silicate, sulfide Includes potassium, aluminum sulfate, sodium bisulfate, zinc sulfate, aluminum chloride and sodium sulfate. Aluminum salts such as sulfates and chlorides are preferred. A preferred crosslinking agent is aluminum sulfate, especially in an amount of 0.25 to 5% by weight, and preferably 0.5 to 1% by weight.
Acids such as acetic acid, hydrochloric acid, sulfuric acid, citric acid and nitric acid, especially 3
Acetic acid used at a pH in the range of ７7 can also be added.

Strong mineral acids having a pH of less than 4 affect the properties of the cellulose fibers present in the feedstock and tend to adversely affect the quality and properties for subsequent reuse of the fibers.
For example, hot hydrochloric acid or sulfuric acid tends to cause degradation and breakage of the fibers, while when cold, those acids cause the fibers to soften and sponge.

Preferred cross-linking agents result in SAP-forming particles, especially hard particles of substantially spherical or hemispherical shape, which can be used, for example, in centrifugal cleaners of the type used for removing sand from pulp. It is easily separated with and from soluble and particulate materials using or by other suitable separation techniques. The formation of hard particles depends on whether the hard particles are untreated SAP or gelled SAP.
Does not shatter or disintegrate in such a way as to shatter or disintegrate under pressure, thus allowing the SAP to be treated like small sand. SAPs that have been crosslinked or treated to reduce swelling tend to be harder and less swelling than untreated SAPs. in addition,
The treated SAP has a specific gravity that is more distinguishable from the specific gravity of water, which aids in the separation in steps in the process of the invention, for example, centrifugation or filtration techniques become practical.

In the embodiment of FIG. 1, liquid moves from module II through outlet 5. This liquid may contain significant amounts of particulate and / or dissolved material, such as urine, excrement, blood and related substances present on or contained in the absorbent paper product. is there. The liquid moves to a settling tank, from which the liquid moves through outlet 7 and the solid material is separately removed (not shown). In such a separation, particulate matter such as cellulosic material and SAP are separated from soluble matter. The particulate matter is preferably obtained using, for example, pulp pressure screening, suction vibration screening or other screening devices, hydrocyclones, core cleaners and the like.
It is further separated into SAP and cellulose part. In a preferred embodiment, the cellulosic material is, for example, Module II
Reintroduced in the process of the invention at I, it may be subjected to a subsequent separation treatment. However, the cellulose portion may find end use or otherwise be processed without further processing. It is preferred to separate the SAP from the cellulose portion if it is to be introduced back into the process of the invention and / or if the cellulose portion is to be used for other end uses. Such separation can be complicated by the agglomeration of the fibers in the cellulose portion around the SAP particles and the resulting tendency to form "fluff balls". Although the use of a surfactant may alleviate possible problems with fluff balls, it is preferred to use a pulper as shown in FIG.

In the embodiment of FIG. 1, the raw material that is transferred from module II to module III is mainly in the form of components of the absorbent sanitary paper product, usually without the SAP and cellulose components of the absorbent sanitary paper product. is there. Subsequent steps in the process of the present invention are primarily directed to converting the feedstock into a form that can be recycled or used in a subsequent process.

In module III, the feedstock is subjected to washing, for example, to further purify the feedstock and remove additives introduced in modules I and II. The pH of the liquid will also tend to be neutral, especially if modules I and II are operated, for example, at an acidic pH.

In module IV, the raw material is further treated with water, in particular with water containing detergent. The detergent solution can enter the module IV through the inlet 9 and move countercurrently to the flow of the raw material into the module III, so that in the module IV the raw material was contacted earlier in the module III Contact with cleaner solution. In embodiments, the solution used in the processing in Module IV can be used as all or part of the feed to Module III. module
The solution in IV produces a raw material for raw material purification, detergent efficiency, bleaching and bleaching and high pH to help them
For example, it will typically have a pH of 11 or more. Preferably, the solution has a temperature of at least 62.5 ° C, and the preferred treatment time is between 4 and 30 minutes.

In modules V and VI, the raw materials are peroxide,
Especially in aqueous solutions of hydrogen peroxide, especially 50 to 500 pp in solution
m, preferably in an amount to provide a free oxygen content of at least 100 ppm. The peroxide bleaches (whitens) the cellulosic component of the feedstock and may also provide some microbicidal treatment of the feedstock. The peroxide solution enters at inlet 10 in module VI and moves through module V and into module IV in a countercurrent manner, during which it is mixed with the detergent solution. Preferably, the amount of peroxide entering module IV is slightly greater than that required to completely process the feed.

The raw material is then washed in module VII and again in module VIII. The latter can be an acidic solution,
And the acids used are weak organic or inorganic acids such as acetic acid or phosphoric acid and must be environmentally safe. In some cases, the market favors cellulosic components that have been treated with acidic solutions, but more typically cellulosic materials that are neutral to slightly alkaline.

In modules IX and X, the raw materials are washed in a countercurrent manner. In these modules, in particular in module IX, the raw material is preferably treated with a microbicide, in particular peracetic acid, but other examples of microbicides are those which release chlorine dioxide or chlorine dioxide. It is a wax medicine. Chlorine-free microbicides are preferred. Treatment with peracetic acid is preferably carried out at a pH of about 9 or greater, but treatment with chlorine dioxide may be at a different pH. The preferred amount of drug is between 100 and 500 ppm, and the preferred treatment time is at least 30 seconds, especially 1-2 minutes. An alternative method of treatment is, for example, the use of an autoclave at elevated pressure and temperature, for example at 120 ° C., using a treatment time of 15 minutes. High intensity microwave irradiation can also be an alternative.

The last processing step in the method of the embodiment illustrated in FIG. 1 is a cleaning step in module XI. The drum in module XI is preferably
It has a relatively large hole, for example about 9 mm in diameter. The washing step and the use of such a drum allows the separation of the cellulose component in the feedstock in this module from the plastic component, for example by flushing the cellulose component from a relatively large plastic component. The cellulosic component may then be dewatered, for example using a dewatering press, and dried.
Examples of dewatering presses include screw type presses and two wheel presses, and other presses that can dewater cellulose pulp material. This dewatering step must increase the solids content to 40-55% by weight, after which the cellulosic component is subjected to a drying step, usually in a flash dryer, convection dryer, infrared or microwave dryer Will. Other types of dryers for drying cellulosic components are also known. A water content of 5-7% by weight is achievable. SAP affects the ability to dry the cellulosic component, and the cellulosic component must contain only low levels of SAP. Plastic components may also be dewatered and dried. The plastic component may be further refined and / or separated into parts.

The method of the present invention has been described with particular reference to embodiments in which the SAP is separated from the method in modules I and II. This is the preferred mode of operation of the method of the invention. However, the method of the present invention also provides a module I
And can be operated without separation of SAP from this method in II. In the latter mode of operation, the level of SAP must be low, for example because the feed to the process of the invention has a low level of SAP, or S
Several steps must be taken to reduce the negative impact of the AP. For example, SAP, as mentioned above,
It may be treated with a crosslinking agent such as aluminum sulphate or a mixture of crosslinking agents.

Although the method of the invention has been described herein with reference to a particular order of steps, it should be understood that this order may be changed, especially after Module II. In some cases, the change in order may affect the resulting product and / or
Or it can have a significant effect on the efficiency of operation of the method of the invention.

In the operation of the embodiment of FIG. 1, the drum of each module is moved to agitate the ingredients in the solution in each module. Beater bars or other devices may be used to increase mechanical action. Preferably, the drum is rotated. After a period of time, the liquid is separated from the feedstock and the feedstock is transferred to the next step of the method of the invention. In this mode of operation, the contact time of the raw materials in each module is the same. If more contact time in a particular solution is required, additional modules can be added to the device for further processing of the raw materials in that solution. Instead, independent rotation of some or all of the drums makes it possible to change the processing time in each module, which can affect the throughput of the method of the invention. is there. Typical contact times are from 2 to 6 minutes, in particular from 2 to 3 minutes, but other times, for example up to 20 minutes, may be used.

In a preferred embodiment, the method of the present invention is illustrated in FIG.
It is carried out in an apparatus as shown in cross section. In one embodiment of the operation, the absorbent sanitary paper product in chopped form is inserted into the inner basket 103. The cleaning solution is then poured into the outer shell 101 or directly into the inner basket 103, preferably so that the liquid level is about half that of the inner basket 103. Inner basket 103
Is rotated in a predetermined direction such that the sieve 106 is a follow-up portion of the separation chamber 105, that is, the washing direction.

After a period of time, the direction of rotation is reversed. Upon reverse rotation, i.e., separation rotation, the particulate matter passes through sieve 106 into separation chamber 105 and through orifice 108 to the separation chamber.
Runs out of 105. The particulate matter then collects near the location of the drain 102 in the outer shell 101.

Liquid and particulate matter may be separately removed from outer shell 101 through valves 109 and 110.

In an embodiment, the apparatus can be used to separate SAP and cellulosic materials from plastic materials, but is capable of separating various combinations of specific particulate matter.

Inner basket 103 may be made of a sieve material, so that particulate matter will flow through the sieve into outer shell 101.

The mesh size of the sieve 106 and of any sieve forming the inner basket 103 is such that only a portion of the particulate material in the shredded absorbent sanitary paper product passes, thereby effecting size separation of the particulate material. It is understood that you can choose as follows.

Using the apparatus shown in FIG. 3, the shredded absorbent sanitary paper product is inserted into the inner basket 203. The drum 201 may be in any desired arrangement, but in a preferred embodiment is in a substantially horizontal arrangement to facilitate loading of the inner drum 203. Next, the inner drum 203 may be rotated by means not shown, and the pulper 210 is operated as required. Otherwise, the method of the present invention operates substantially as described above. Drum 201
Prior to discharging the contents of the drum 201, the drum 201 is inclined, especially in a vertical arrangement. If you are not already driving,
The pulper 209 is operated to comminute the particulate matter in the drum 203 to such an extent that the solid matter can pass through the holes 207.

The material or particulate matter and solution discharged from the drum shown in FIGS. 2 and 3 may be processed in the manner described with respect to FIG. Alternatively, the material may be recycled back into the apparatus of FIGS. 2 and 3 and subjected to further processing in these apparatuses according to the method of the present invention.

It is to be understood that in embodiments where the material is exposed to pulper and core cleaner, the solids concentration will decrease significantly from module I to core cleaner. For example, operation in module I may operate on the feedstock in its various forms such that a slurry having a solids concentration of about 6 to 12% by weight is obtained. For the pulping step, the concentration of the slurry should be reduced to about 4-6% by weight, and in the core cleaner the concentration of the slurry should be about 0.4-1.2% by weight. Similar changes in preferred concentrations will occur for other modes of operation of the method of the present invention.

In one embodiment of the present invention, a portion that includes both a cellulose portion and a plastic portion may be separated from module I, for example. The separated portion may be disinfected at a low pH, and the superabsorbent polymer present in the portion may then be crosslinked to produce particulate matter, for example, in the form of small sand. The product formed may be dried and subjected to air separation, which will give a fibrous and small sand portion.

In one preferred embodiment, the solid in module I is applied to the pulper in that module. The particulate matter discharged from module I is passed through a screening sieve to remove large particulate matter and then through one or more core cleaners.

The method of the invention has been described with particular reference to FIG. 1 and the use of a module following module II, which is in the form of a rotatable drum. Although this would be advantageous, it would also be advantageous to operate such a part of the process of the invention using other agitated devices such as agitated tanks.

Although operation has been disclosed as continuous, non-continuous operation may also be used. In the latter, a sieve may be placed over the orifice 108 and a different mesh sieve may be placed inside the separation chamber 105. When the operation is stopped, particulate matter having different particle sizes can be separated and taken out.

After washing of the absorbent sanitary paper product, the residual material is further processed in the same apparatus using a process specifically designed for the residual material using the steps previously described herein. Or may be removed from the apparatus of FIG. 2 and processed in another apparatus. In one embodiment, the material remaining in the device is removed by vacuum, especially after partial drying.

In the separation of solids or particulate matter from liquids, especially liquids used in the treatment of particulate matter, the means of separation may involve simultaneous application of a solution, especially water, to the particulate matter during the spinning or centrifugation step. It should be understood that this may include the use of spin or centrifugation techniques, including spraying. Such spraying will aid in the purification of the particulate matter, in particular the removal of other liquids present on the particulate matter.

In its entire context, the invention is provided by manufacturers of products, such as from homes, institutions and hotels,
I.e., collection of the absorbent sanitary paper product after use in a plastic bag or other suitable collection container, such as a polyethylene bag, e.g., about 0.75 micron thick, that may be included in the diaper packaging for sale. Will enable a recycling system. These containers are
It will then be transported to a processing facility and stored, usually refrigerated, prior to being processed for processing of the absorbent sanitary paper product and recovery of reusable components. The bag or collection container may remain sealed until it is actually supplied to the method of the invention. These products will then be processed according to the method of the present invention.

The cellulosic material obtainable from the process of the present invention is a relatively non-deteriorated and unpurified material as compared to cellulosic material that has been subjected to methods for the manufacture of paper, tissue or towels and the like. In addition, the cellulosic material is cleaner or whiter than the cellulosic material available from many other sources. It has potential for use in a wide variety of end uses, such as absorbent sanitary paper products, and fine and other paper making. All main dimensions are 3-6m
plastic components and mixtures of polyethylene and polypropylene in fibrous and sheet form, elastic and spandex components, small amounts of SAP and certain cellulosic materials, which are finely divided to the order of m It has been found to be particularly effective in absorbing oil from oil / water mixtures. SAP can be recovered from its bridged state, such as from module II in the above-described embodiment, and can be achieved by high intensity gamma rays or other treatment that depolymerizes SAP. It may be used for the recovery of monomers, as an abrasive or other filler and in agricultural end uses for controlled release of water or additives.
Many of the solutions used in the methods of the present invention may be processed for component recovery or may be used elsewhere or in the methods of the present invention. Plastic components may also be used as either filled or unfilled compositions, for example in the manufacture of plastic / wood products or cast or molded products, without further separation of the components. May be used. Instead, the plastic component is used to separate the elastic components, to separate the polyethylene and polypropylene components,
Further processing may be performed to separate other components that may be present. Such upgraded plastic components can be used in end-use applications that have higher requirements on the materials that can be used.

Here, a specific example of a method of separating each member constituting the sanitary paper product of the present invention will be described with reference to the batch apparatus shown in FIG.
This will be described with reference to the drum shown in FIG.

 First, used diapers are shredded.

Next, the shredded disposable diaper is washed with washing water in the module I to dissolve the urine absorbed in the disposable diaper in the washing water, and the washing water is removed from the module I.

Next, the disposable diaper is introduced from the module I to the drum 100 (FIG. 2) in the module II. An aqueous solution containing a water-soluble compound such as an alkali metal is introduced to half the depth in the drum 100.

Next, the drum 100 is rotated counterclockwise, and the agitator 104 is rotated.
Crush the solid part. At this time, the urine remaining in the disposable diaper is completely dissolved in the aqueous solution. Superabsorbent polymers, on the other hand, are cross-linked by water-soluble compounds, shrink, become harder, have a higher specific gravity, and are converted to particulate matter in the form of small sand.

Next, when the rotation direction of the drum 100 is reversed and changed clockwise, the superabsorbent polymer, cellulose, and the aqueous solution as particulate matter pass through the sieve 106 and are discharged from the lower part of the drum through the orifice 108. At this time, coarse plastic that cannot pass through the sieve 106 remains in the drum 100.

Next, the superabsorbent polymer, cellulose and aqueous solution discharged outside the drum are transferred to the sedimentation tank 6 (FIG. 1) via the liquid outlet 5 (FIG. 1). Next, in the sedimentation tank 6, the superabsorbent polymer and cellulose as the particulate matter are settled,
Separate from aqueous solution.

Next, the precipitated superabsorbent polymer and cellulose are separated by centrifugation using a hydrocyclone or the like (not shown) to separate the superabsorbent polymer and cellulose.

Next, the separated cellulose is re-introduced into Module III, and the plastic remaining in the drum of Module II is introduced into Module III.

Then, in each module after the module III, each operation such as washing, bleaching, whitening, disinfection, etc. is performed. Leave in. The plastic remaining in the drum is collected by vacuum suction. Thus, purified cellulose and plastic are obtained.

 The present invention is illustrated by the following examples.

Example I A series of tests were performed to test the effects of various aqueous liquids on SAP particles. 2 for each test
Times. SAP used was Greensboro, NC, USA
Favor ^™ SAB 800 superabsorbent polymer obtained from Stockhausen, Inc.

Place two SAP particles having a volume of each approximately 0.7 to 1.0 mm ³ on a microscope slide, and the dimensions of the particles were measured. The particles were then contacted with the solution and the size of the particles was monitored over a period of 20 minutes. The solution was then absorbed away from the particles and the size of the particles was further monitored.

Further experimental details and the results obtained are given in Table I. The data reported in Table I is the relative volume of the SAP particles.

These results indicate that SAP particles absorb a significant amount of water and increase in volume significantly. For example, in distilled water, SAP particles increased in size by a factor of 141. However, the addition of aqueous solutions of copper sulphate, aluminum sulphate or citric acid resulted in a substantially smaller volume increase and also caused the swollen particles of SAP to undergo a substantial decrease in volume. That is, the swelling caused by the water was reversed.

The particles change morphology and physical properties when exposed to the cross-linking agent, and become spherical in shape, undergo significant changes in specific gravity and become hard. The change in specific gravity and the increase in hardness
Leading to easier physical separation of SAP.

Example II A series of batches of diapers were subjected to the processing method disclosed herein using a laboratory 36 kg batch tunnel washing machine consisting of three modules. A total of 55 batches of soiled diapers were cut open from the collection bag and each of the following batches was subjected to the following steps: (a) a rinse cycle using water for a period of 6 minutes, (b) a total volume of 144 liters 156 ml of nonionic detergent (Ecolab detergent # 1 from Ecolab Ltd. of Mississauga, Ontario, Canada) and 1625 ml of alkali (Ecolab
(C) 57 ml of detergent in 144 liters of solution, 1573 ml of alkaline solution and 255 ml of hydrogen peroxide (Ecolab Oxybrite) in a 9 minute period using an aqueous solution containing SL2000, 29% NaOH).
(Equivalent to 35%) in a solution of about 62.5 ° C. in a main wash cycle of 6 minutes at (d) a rinse cycle of 3 minutes in water, (e) a solution of 1305 ml of acetic acid in 144 liters of solution (F) Rinse cycle in solution containing 1400 ml of chlorine dioxide (20000 ppm concentration) in 144 liters of solution.

Pouring from this method involving cellulose fibers left the plastic component. Both the cellulosic fibers and the plastic component were recovered and dried.

The diaper batch consisted of three different configurations of different proportions of diapers. Both of these diapers
Luvs ^(R) and Pampe available from Procter and Gamble
rs ^(R) , and Huggies ^(R) from Kimberly-Clark. Changed the composition of the batch. Some batches are 100% H
The batches contained uggies or 100% Pampers, but batches are more typically 37-38% Huggies, 43-49% Pampe
It contained rs and 14-20% Luvs. Each batch size was about 12 kg.

The results show good separation of SAP from the cellulose component, as well as SAP from the plastic component in the diaper.
And that very good separation of the cellulose components could be obtained. The cellulosic component was bright white with its original appearance in altitude. There was no evidence of problems due to the presence of so-called "stickies" from the adhesive on the washing machine screen or other parts. The plastic components remained in place with the spandex portions and tape tabs attached to them.

Example III A pilot plant scale device for the treatment of absorbent sanitary waste, especially diapers, was assembled by retrofitting a standard horizontal linen washing machine with a capacity of 23 kg. The washing machine was modified as follows: (a) The inner drum was lined with a fine stainless steel mesh that could hold the wood pulp, superabsorbent polymer and plastic components while allowing the liquid to pass through.

(B) In the manner shown in FIG.
oop). This created a gate into the space between the inner and outer drums. The gate was interrupted by a round hole having a diameter of 0.95 cm.

(C) A seal was placed on the washing machine door so that the wood pulp, superabsorbent polymer and plastic components were retained inside the inner drum.

(D) Three sets of sharp tooth-like blades were attached to the inner drum to increase mechanical action and to tear open the diaper inside the drum.

(E) A 50 L reservoir was added to the bottom of the outer drum to hold the liquid and slurry separated from the inner drum.

(F) The drive motor for the drum was replaced with a variable speed motor. It is understood that the rotation of the drum was opposite to that described with respect to FIG.

(G) A two-liquid port was added to the bottom of the storage tank of the washing machine. One of these ports was unblocked and was for the removal of wood pulp and superabsorbent polymer slurry from the washing machine. Another had an air pressure purification system and was for the removal of liquid from the washing machine.

(H) Two vacuum ports were added to the washing machine. One in the door
One was for the diaper addition and another in the top of the container was to create a vacuum inside the washing machine, thereby facilitating the addition of the diaper to the washing machine.

Storage containers equipped with pumps and recycling systems,
Supplied for washing and chemical solutions and, where appropriate, for use and reuse of these solutions. A settling tank was provided for the effluent from the process, from which the solid material could be drained and the liquid could be recycled back to the process.

A means was provided for transporting the slurry of wood pulp and superabsorbent polymer from the washing machine reservoir to the hydropulper. This hydropulper is shown in FIG. 3 in different contexts.
Similar in design to the one shown. The pulper head was rotatable at 750 rpm. That is, 110m / min
Blade speed. The slurry from the hydropulper could be transported to a storage room, from which it was (i) vibrated barrier sieve for removal of coarse contaminants such as plastic and tissue pieces, and (ii) bridged. Positive-flow centrifugal cleaner for removal of superabsorbent polymers and other heavy contaminants, and (iii) uni-flow cleaner for removal of light weight contaminants. .

The plastic components remaining in the drum of the washing machine could be removed and pulp hydropulped, then recycled back to the washing machine and further wood pulp could be separated therefrom, as described above. The resulting plastic component could be removed from the washing machine and dried, and the pulp treated as described above.

The pulp separated from the process is dewatered, bleached,
It could be disinfected and rinsed and finally dehydrated and dried.

The apparatus described above has been configured to develop an effective method of recycling the components of a disposable diaper. Although there are many variations in the manner in which the device can be operated in accordance with the present invention, the following experiment will outline the procedure for treating diapers.

Fifty dirty diapers were collected from local households. These diapers are Pampers ^(R) diapers manufactured by Procter & Gamble, and were large size and diapers that are colored in the color of the girl. These diapers had inner and outer plastic sheets, and the inner one was permeable to moisture with an intermediate core of wood pulp containing superabsorbent polymer.

All of these diapers were placed in the washing machine. Next, the charge of the washing machine drum is rotated at a speed that saturates the charge with water and provides maximum agitation, i.e., carrying the washing machine charge to the top of the drum and then dropping it to the bottom of the washing machine drum. Rolled by rotation. This effect lasted 1 minute. It has been observed that the blades on the inner drum effectively unwind the diaper ball and tear the outer or non-woven topsheet of the diaper, thereby helping to release the wood pulp from the diaper.

Next, 100 liters of the washing solution were added to the washing machine. This solution contained 100 mL of concentrated detergent. The charge was then rolled with maximum mechanical action for a period of 3 minutes.

The concentrated solution of sodium sulfate was added to the washing machine such that the concentration of sodium sulfate in the washing solution was 0.5% by weight. The superabsorbent polymer was observed to shrink dramatically.
Rolling the charge in sodium sulfate solution for a period of 1.5 minutes,
Thereafter, the solution was pumped from the washing machine through the filter in the reservoir to the effluent tank.

The washing machine was filled with fresh rinsing water and the washing machine charge was rolled in the rinsing water for a period of 2 minutes. The rinse water was then removed from the washing machine through a filter in a reservoir and stored in a tank for subsequent reuse as a washing solution for the next batch of soiled diapers.

The washing machine was filled with a solution of a mixture of 2% sodium sulfate and 1% aluminum sulfate. The washing machine charge was then rolled in this solution for a period of 2 minutes. It was observed that the properties of the superabsorbent polymer had changed from a soft sponge-like rubbery material to a hard, small sandy material. This is believed to be a bridging effect. The solution was removed to a reservoir through an outlet with a filter and sent to a storage tank for subsequent reuse in the next batch of dirty diapers.

The washing machine was then filled with fresh water and rotated for a period of 3 minutes in the direction of separation, i.e. opposite to the direction of rotation previously used. Using moderate speed rotation, the scoop moved through the slurry inside the washing machine at moderate speed, and the pulp and superabsorbent polymer were separated from the plastic and transported into the washing machine tub. . Upon visual inspection, about 95% of the pulp / superabsorbent polymer was removed from the plastic during this separation. The pulp / superabsorbent polymer slurry was collected in a washing machine reservoir and then pumped to the hydropulper.

100 liters of water was added to the hydropulper to produce 250 liters of total liquid content. This is 1% consistency,
That is, a slurry solution having a solid content of 1% was produced. Other batches were run in the pulper at a consistency of up to 8%.

The pulper was operated for a period of 3 minutes. The resulting slurry was then transported to a storage tank and maintained in a stirred storage tank.

The plastic component was removed from the washing machine by vacuum and transferred into the hydropulper. 100 liters of water was added and the resulting slurry was pulped for 1 minute. Next, the slurry was dewatered and returned to the washing machine under vacuum. Water was added to the washing machine, and the washing machine was then operated in separation mode, ie, with reverse rotation of the drum, for a period of one minute. The recovered fiber was combined with the fiber and superabsorbent polymer slurry in the stirred storage tank. After adding more water to reduce the consistency of the slurry, i.e., reduce the solids content, the slurry is fed to a vibrating barrier sieve, a positive-flow cleaner and a uni-flow cleaner to remove the wood pulp from the superabsorbent polymer. Separated, but the superabsorbent polymer was in the form of small sand.

Plastic component is made of sodium hydroxide (pH 1
2) and disinfected in a washing machine with a solution of peracetic acid (1.5% by weight). Next, the plastic component was dewatered and rinsed with water for a period of one minute. Next, the plastic component was dried in a tumble dryer for a period of 25 minutes. This plastic component was observed to contain very little wood pulp. Most of the glue line on the diaper backsheet appeared to remain intact, indicating that most of the adhesive remained with the plastic component. It was also observed that most of the wet strength tissue (latex coated tissue) used in the diaper construction remained with the plastic component.

This plastic component was granulated into a fluffy material suitable as a commercial oil absorbent.

As noted above, the wood pulp contained in the agitated storage tank was processed sequentially through a vibrating barrier slot sieve, a hydrocyclone, a positive-flow cleaner and a hydrocyclone uni-flow cleaner.

Large pieces of tissue (about 2.5 x 2.5 cm or less) and large pieces of plastic were observed to be the major components in the rejected flow of the vibrating barrier sieve. These rejects were collected and dried in air.

The slurry from the vibrating barrier sieve was pumped through a uni-flow cleaner. It was observed that very little contaminant was present in the rejected stream in the sieve of the uni-flow cleaner. These rejects are mainly
It consisted of small pieces of tissue (0.3 x 0.3 cm), small pieces of plastic, and a very small group of wood pulp that appeared to be joined together by very small pieces of adhesive. The slurry was passed twice through a uni-flow circuit.

Next, the slurry was pumped through a positive-flow centrifuge cleaner. This cleaner aggressively removed the crosslinked superabsorbent polymer from the slurry. The slurry was passed through this circuit a total of four times. Rejects were collected in a large feed tank. Examining the rejects, they found that about 60-70% superabsorbent polymer, 30-40%
And a small amount of tissue. The slurry from the positive-flow circuit was placed in a stirred storage tank.

The reject collected from the positive-flow cleaner was stirred vigorously. The reject in the form of a slurry was then pumped through a total of three cycle positive-flow circuits. Examination of the positive flow reject thus obtained showed that the fiber content had been significantly reduced. The rejected stream now contains about 85% of the superabsorbent polymer as well as 15%.
% Fiber and other small contaminants of tissue fines and other small sand contaminants.
The fiber recovered from this method was added to the previously obtained fiber slurry.

The superabsorbent polymer slurry was dewatered on a fine mesh sieve, collected and placed in a fine mesh polyolefin bag. The bag and its contents were then washed with detergent in a standard household washing machine and dried in a household dryer. It was observed that the superabsorbent polymer and the wood pulp fiber spontaneously separated from each other during the drying process. Fiber has a diameter of about 0.6 ~
Gathered together as a small 1.0mc ball. The superabsorbent polymer and fibers were then separated from each other using a small vibrating sieve. The holes in the sieve were about 0.3 cm square.
Next, a solution of sodium hydroxide (pH 11) was added to the measured and measured amount of superabsorbent polymer. The superabsorbent polymer absorbs caustic solution to reduce its size by about 5-10
Double swelling was observed. Thus, the caustic solution appears to reverse the supercross-linking effect created by aluminum sulfate. The recycled superabsorbent polymer is charged with nitrogen and other nutrients, and it is believed that it can be used as a controlled release agent in fertilizer or agriculture.

The wood pulp or fiber slurry was transferred to a hydropulper. In the hydropulper, the slurry was prepared by adding sodium hydroxide (pH 12) and hydrogen peroxide (1%) at 75 ° C.
Dehydrated in a hot bath. The slurry was pulped for a period of 3 minutes. Next, the slurry was dewatered and a new batch was introduced. The new batch is sodium hydroxide (pH 9.
5) and a hot solution (75 ° C.) of peracetic acid (1.5%).
The slurry was pulped in this solution for a period of 3 minutes. Next, the slurry was dewatered and rinsed with fresh water. A small amount of acid (citric acid) was added to the rinse solution to adjust the pH to 7. Next, the slurry was dewatered on a fine mesh sieve.

The pulp was observed to be substantially free of any contaminants. The superabsorbent polymer could not be detected visually or by touch. The pulp appeared vivid white and very smooth and silky to the touch. Upon close inspection, only a very small number of plastic debris and very small sands could be detected. In the first test, the pulp appears to have a shine and physical entity that is reused in sanitary paper applications. A previous morphological test in a previous recycle test batch is consistent with this observation.

Continued on the front page (72) Inventor J.Just, François El0R 1Canada 1B5 Ontario Beamsville Fraison Boulevard 5006 (72) Inventor Smith, Michael Davids 6Educs 2Canada 2Doubleau 5 Ontario Canada Brampton Rose Bud 74 (56) References Special Table 58-186615 (JP, A) MONWOVENS WORLD vol. 56, No. 2, August 1990, page 12 (58) Fields investigated (Int. Cl. ⁷ , DB name) D21B 1/32-1/34 A61F 13/15-13/551 B09B 3/00 C08J 3/24

Claims (30)

(57) [Claims] 1. A method of treating a sanitary paper product comprising a superabsorbent polymer, said product comprising plastic, cellulose and a solid portion of a superabsorbent polymer, said method comprising: Treating in at least one bath of an aqueous solution, (b) dissolving a soluble substance from the product in the aqueous solution, and (c) converting the superabsorbent polymer to an alkali metal, alkaline earth metal, aluminum, copper (II) ), Treating with at least one water soluble compound of iron (III) and zinc to reduce swelling of the superabsorbent polymer in the aqueous solution. 2. The method of claim 1 wherein the superabsorbent polymer is treated to reduce swelling of the superabsorbent polymer and to crosslink the superabsorbent polymer to form a particulate material. 3. The method according to claim 2, wherein the superabsorbent polymer is crosslinked in a bath. 4. The aqueous solution in at least one bath comprises a water-soluble compound used to reduce swelling of the superabsorbent polymer, and the aqueous solution is later reused in the process. 3. The method of claim 2. 5. The method according to claim 1, wherein the operating temperature of the bath is 70 ° C. or less. 6. The method of claim 1 wherein the bath has a pH in the range of 3-8. 7. The method of claim 1, wherein step (a) comprises the use of a pulper and / or a stirrer. 8. The method of claim 1, wherein the method is performed in a single drum or using a monoshell. 9. The method of claim 1 wherein the aqueous solution is reused in said method. 10. The method of claim 1, wherein the product is contained in a collection container, and the collection container is also treated in the method. 11. The method of claim 1, wherein the solid portion is treated with an antimicrobial agent. 12. The method of claim 1, wherein the product is shredded prior to treating the product in at least one bath of the aqueous solution. 13. The step of treating the product with the water-soluble compound in at least one bath comprises the step of batch washing the product in a first aqueous bath, followed by the treatment in at least one additional aqueous bath. Claims comprising the steps of:
Method according to 12. 14. The solid part in at least two parts, one of which substantially comprises particulate matter,
13. The method of claim 12, further comprising the step of separating into another part substantially comprising a plastic portion. 15. The method of claim 14, wherein the superabsorbent polymer is heated to reduce swelling of the superabsorbent polymer and to crosslink the superabsorbent polymer to form a particulate material. 16. The method of claim 14, wherein the superabsorbent polymer is separated from other particulate matter. 17. The method of claim 14, wherein the step of separating the solid portion into at least two parts comprises producing separate streams, ie, a stream containing a plastic portion and a stream containing a cellulose portion. the method of. 18. The method of claim 17, wherein the superabsorbent polymer is treated to reduce swelling of the superabsorbent polymer and to crosslink the superabsorbent polymer to form a particulate material. 19. Separating the particulate matter into two streams, one stream substantially comprising the cellulose portion and the other into a stream substantially containing the superabsorbent polymer portion. 15. The method of claim 14, further comprising: 20. The method of claim 1, wherein at least one portion of the particulate matter is treated with at least one aqueous washing solution and a bleaching agent.
20. The method according to claim 19, further comprising an additional subsequent step of treating with at least one aqueous solution of at least one of a brightener and an antimicrobial agent. 21. The method of claim 19, wherein the step of treating the superabsorbent polymer with a water-soluble compound to reduce swelling of the superabsorbent polymer changes the specific gravity of the superabsorbent polymer particles. 22. The method of claim 21, wherein the step of separating the solid portion is performed using at least one of a hydrocyclone, a positive-flow centrifugal cleaner, and a core cleaner. 23. The method of claim 22, wherein the superabsorbent polymer portion is separated in the form of small sand. 24. The water-soluble compound is an aluminum salt.
The method of claim 1. 25. The method according to claim 1, wherein the aluminum salt is aluminum sulfate. 26. The method according to claim 1, wherein the aluminum salt is aluminum chloride. 27. The amount of aluminum sulfate is 0.25 to 5% by weight.
26. The method according to claim 25, wherein 28. The amount of aluminum sulfate is 0.5 to 1% by weight.
26. The method according to claim 25, wherein 29. A method of treating a sanitary paper product comprising a superabsorbent polymer, said product comprising plastic, cellulose and a superabsorbent polymer portion, said method comprising: Treating the product with an aqueous solution under conditions that help to non-destructively separate the components; (b) crosslinking the superabsorbent polymer; and (c) subsequently separating the product into at least three parts: That is, one part substantially containing a soluble substance, the other part substantially containing a crosslinked superabsorbent polymer, and another one of at least one of a plastic part and a cellulose part. Separating into a part substantially comprising: 30. The method of claim 29, wherein the crosslinked superabsorbent polymer is separated from the cellulose moiety using a hydrocyclone or a core cleaner.