WO2022086456A1 - Process for deinking and desiliconizing paper product - Google Patents

Process for deinking and desiliconizing paper product Download PDF

Info

Publication number
WO2022086456A1
WO2022086456A1 PCT/TH2021/000064 TH2021000064W WO2022086456A1 WO 2022086456 A1 WO2022086456 A1 WO 2022086456A1 TH 2021000064 W TH2021000064 W TH 2021000064W WO 2022086456 A1 WO2022086456 A1 WO 2022086456A1
Authority
WO
WIPO (PCT)
Prior art keywords
paper
process according
silicone
paper product
pulp
Prior art date
Application number
PCT/TH2021/000064
Other languages
French (fr)
Inventor
Nikorn LAOCHAROEN
Taweewat TRIPATTHARANAN
Jarun LOMRATSIRI
Pattira PATTARASOPACHAI
Original Assignee
Scg Packaging Public Company Limited
Thai Paper Company Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from TH2001006094A external-priority patent/TH2001006094A/en
Application filed by Scg Packaging Public Company Limited, Thai Paper Company Limited filed Critical Scg Packaging Public Company Limited
Publication of WO2022086456A1 publication Critical patent/WO2022086456A1/en

Links

Classifications

    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21BFIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00Fibrous raw materials or their mechanical treatment
    • D21B1/04Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
    • D21B1/12Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
    • D21B1/30Defibrating by other means
    • D21B1/32Defibrating by other means of waste paper
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21CPRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C5/00Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
    • D21C5/02Working-up waste paper
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00Technologies for solid waste management
    • Y02W30/50Reuse, recycling or recovery technologies
    • Y02W30/64Paper recycling

Definitions

  • the used paper that contains contaminants such as printing ink will be recycled to remove the ink, and then the recycled pulp obtained will be reused for paper production.
  • the used silicone coated paper or siliconized glassine paper are usually disposed, for example, by means of incineration or landfill, which will subsequently cause environmental problems.
  • a recycling method for separating or removing silicone from the paper by optimizing the conditions of the existing printing and writing paper deinking process is a low- cost method since this can be done using devices or machines existing in the printing and writing paper deinking process and can help solve the paper waste management problems and environmental problems by reusing the recycled pulp as a raw material in the paper production.
  • US 5,634,405 discloses a method for deinking the substrate comprising thermoplastic resin. Such method comprises contacting the substrate with an aqueous solution of glycol ether for a sufficient period of time under an effective condition.
  • US 5,567,272 discloses a process for recycling silicone coated paper by using monophosphoric ester salt. Such process comprises a step of pulping using a disintegrator under the basic pH of 10- 12 and at the temperature ranging from 60- 80 °C with one or more types of monophosphoric ester salt, and a step of paper sheet reformation.
  • US 1,628,931 discloses a method of recycling waxed paper using trisodiumphosphate in the basic environment. Such recycling method can be used to remove wax and ink from the paper at the same time.
  • the prior arts above disclose the methods of deinking and/ or desiliconizing the paper, there is still a need to invent and develop the highly effective methods of deinking and desiliconizing the paper product that can be applied to the existing printing and writing paper deinking process, and that yields the recycled pulp with no silicone or minimum amount of silicone left which does not negatively affect the properties of pulp or paper made of the recycled pulp in application e.g., strength, printing quality, etc.
  • the objective of the present invention is to provide a process for deinking and desiliconizing paper product using chemicals in conjunction with adjustment the conditions of the existing deinking processes for printing and writing paper so that the invented process can be used for recycling the silicone coated paper or siliconized glassine paper in a highly effective manner, and to obtain the recycled pulp with the minimum amount of contaminants, particularly silicone, preferably less than 100 ppm, which will not affect the properties of pulp or paper made of such recycled pulp, especially the strength and printing properties.
  • the present invention relates to a process for deinking and desiliconizing paper product comprising the steps of:
  • step (ii) removing ink and silicone from the slurry of the treated pulp of step (i).
  • the present invention also relates to the recycled pulp obtained from the process for deinking and desiliconizing paper product according to the present invention, as well as the paper made of such recycled pulp.
  • the process for deinking and desiliconizing paper product according to the present invention provides a high deinking efficiency of 95-98% and a high siliconizing efficiency of about 90-99%. Furthermore, the paper made of the recycled pulp obtained from the deinking and desiliconizing process according to the present invention has better physical properties e. g. , strength and density than those of paper made of the conventional recycled pulp and can also be used for printing.
  • Fig. 1 is an example of color printing on paper samples, i.e., (a) a paper sample which is made of the recycled pulp obtained from the printing and writing paper that has not undergone the deinking and desiliconizing process according to the present invention, (b) a paper sample which is made of the recycled pulp obtained from the paper product sample comprising the printing and writing paper and silicone coated paper that have not undergone the deinking and desiliconizing process according to the present invention, (c) a paper sample which is made of the recycled pulp obtained by putting the printing and writing paper into the deinking and desiliconizing process according to the present invention, and (d) a paper sample which is made of the recycled pulp obtained by putting the paper product sample comprising the printing and writing paper and silicone coated paper into the deinking and desiliconizing process according to the present invention.
  • Fig. 2 is a graph that shows a comparison of physical properties of (a) a paper made of recycled pulp obtained from the conventional deinking process and (b) a paper made of the recycled pulp obtained from the deinking and desiliconizing process according to the present invention.
  • the process for deinking and desiliconizing paper product comprising the steps of:
  • step (ii) removing ink and silicone from the slurry of the treated pulp of step (i).
  • paper product is meant to encompass used paper, piece of paper or paper waste.
  • the paper product that can be used in the deinking and desiliconizing process according to the present invention may be used paper of any types such as the printing and writing paper, silicone coated paper, siliconized glassine paper or a mixture thereof.
  • the paper product for the deinking and desiliconizing process according to the present invention is a mixture of a used printing and writing paper and a used silicone coated paper.
  • the silicone coated paper includes the siliconized glassine paper.
  • a ratio of the printing and writing paper to the silicone coated paper used in the deinking and desiliconizing process according to the present invention is in a range of 75- 99: 1- 25, preferably in a range of 75-90:10-25, more preferably 80:20.
  • the aqueous solution used in step (i) is a mixed solution of alkylene glycol ether, sodium hydroxide, sodium silicate, hydrogen peroxide, and surfactant in water.
  • such aqueous solution comprises alkylene glycol ether in an amount ranging from 0.1-1 wt% based on the weight of silicone coated paper.
  • the alkylene glycol ether may be selected from a group consisting of ethylene glycol ether, propylene glycol ether, and a mixture thereof.
  • the alkylene glycol ether is ethylene glycol ether.
  • the aqueous solution comprises sodium hydroxide in an amount ranging from 1-5 kg/ton of paper product.
  • the aqueous solution comprises sodium silicate in an amount ranging from 1 -5 kg/ton of paper product.
  • the aqueous solution comprises hydrogen peroxide in an amount ranging from 1-4 kg/ton of paper product.
  • the surfactant is a nonionic surfactant, whereby the nonionic surfactant can be selected from a group consisting of alcohol alkoxylate, alcohol ethoxylate, and a mixture thereof.
  • the nonionic surfactant can be selected from a group consisting of alkoxylated phosphate ester, ethoxylated alkyl amine, and a mixture thereof.
  • the nonionic surfactant is a mixture of alkoxylated phosphate ester and ethoxylated alkyl amine.
  • the surfactant according to the present invention comprises alkoxylated phosphate ester in an amount ranging from 0.1-1 kg/ton of printing and writing paper. Still more preferably, the surfactant according to the present invention comprises ethoxylated alkyl amine in an amount ranging from 0.01- 0. 1 wt% based on the weight of silicone coated paper.
  • the pulp fractionation and paper product treatment in step (i) are performed by using a mechanical treatment in conjunction with a chemical treatment at a temperature ranging from 50- 60 °C , pH ranging from 9- 11, for 15-30 minutes, more preferably 25-30 minutes.
  • the slurry of the treated pulp of step (i) has a consistency ranging from 12-17%.
  • the removal of ink and silicone from the pulp slurry in step (ii) is performed by means of screening, centrifugation, or flotation.
  • the removal of ink and silicone from the pulp slurry in step (ii) is performed by means of flotation comprising passing the slurry of the treated pulp of step (i) into a flotation apparatus/system or a flotation cell which contains a mechanical mechanism for producing many air bubbles.
  • a flotation apparatus/system or a flotation cell which contains a mechanical mechanism for producing many air bubbles.
  • the ink and silicone particles which are hydrophobic will attach to the air bubbles formed and float to the top surface of aqueous solution.
  • such bubbles with the ink and silicone particles attached will be separated and transferred for disposal, e. g. , by means of incineration to produce heat energy at a boiler.
  • step (ii) the removal of ink and silicone from the pulp slurry in step (ii) is performed by means of flotation at a temperature ranging from 50-60 °C, under an air pressure ranging from 30-40 kPa.
  • the removal of ink and silicone from the pulp slurry in step (ii) may comprise ensuring the slurry of the treated pulp of step (i) has a consistency of 1% prior to flotation.
  • the removal of ink and silicone from the pulp slurry in step (ii) is performed by applying flotation twice.
  • the second flotation is applied at the temperature ranging from 50- 60 °C , under the air pressure ranging from 10-20 kPa.
  • the removal of ink and silicone from the pulp slurry in step (ii) may further comprise a size reduction and dispersion of ink, silicone, and other contaminants which are carried out after the first flotation.
  • the size reduction and dispersion of ink, silicone, and other contaminants are carried out by means of a mechanical treatment at a temperature ranging from 100- 120 °C, by intensive kneading with a specific energy consumption (SEC) ranging from 100-130 kWh/ton of paper product.
  • SEC specific energy consumption
  • the SEC used for the size reduction and dispersion of ink can be optimized based on the initial pulp freeness. For example, the SEC used in intensive kneading can be increased up to 150 kWh/ton of initial paper product sample.
  • the deinking and desiliconizing process of this invention may further comprise soaking the paper product in an aqueous solution at a temperature ranging from 50-60 °C, pH ranging from 9-11, for 15-30 minutes before proceeding to step (i).
  • step (ii) that is performed by means of flotation can be performed in many ways. For example:
  • the removal of ink and silicone from the pulp slurry in step (ii) comprises applying flotation only once.
  • the removal of ink and silicone from the pulp slurry in step (ii) comprises the first flotation and the second flotation, respectively.
  • the removal of ink and silicone from the pulp slurry in step (ii) comprises the first flotation, the size reduction and dispersion of ink, silicone, and other contaminants, and the second flotation, respectively.
  • the removal of ink and silicone from the pulp slurry in step (ii) comprises soaking the paper product in the aqueous solution with components of the type and in the amount as specified above, the first flotation, the size reduction and dispersion of ink, silicone, and other contaminants and the second flotation, respectively.
  • the size of bubbles formed in the flotation cell of the second deinking and desiliconizing flotation would be smaller than those formed in the flotation cell of the first deinking and desiliconizing flotation, allowing better performance of the pulp deinking and desiliconizing process.
  • the amount of ink and silicone contained in the pulp before and after the first and second flotations was measured for comparison of deinking and desiliconizing efficiencies of the process.
  • Paper product samples are:
  • the silicone coated paper used in this test comprises approximately 50% long- fiber pulp and approximately 50% short-fiber pulp.
  • Aqueous solution samples are:
  • Aqueous Solution 1 comprising sodium hydroxide in the amount of 2 kg/ ton of paper product, sodium silicate in the amount of 3 kg/ ton of paper product, hydrogen peroxide in the amount of 2 kg/ton of paper product, and alkoxylated phosphate ester surfactant in the amount of 0.1 kg/ton of paper product,
  • Aqueous Solution 2 comprising sodium hydroxide in the amount of 2 kg/ton of paper product, sodium silicate in the amount of 3 kg/ton of paper product, hydrogen peroxide in the amount of 2 kg/ton of paper product, and fatty alcohol alkoxylate surfactant in the amount of 0.1 kg/ton of paper product,
  • Aqueous Solution 3 comprising sodium hydroxide in the amount of 2 kg/ton of paper product, sodium silicate in the amount of 3 kg/ton of paper product, hydrogen peroxide in the amount of 2 kg/ton of paper product, and a mixture of alkoxylated phosphate ester surfactant, alcohol ethoxylate surfactant and propylene glycol ether in the amount of 0. 1 kg/ton of paper product,
  • Aqueous Solution 4 comprising sodium hydroxide in the amount of 2 kg/ton of paper product, sodium silicate in the amount of 3 kg/ton of paper product, hydrogen peroxide in the amount of 2 kg/ton of paper product, and a mixture of alkoxylated phosphate ester surfactant, alcohol ethoxylate surfactant and ethylene glycol ether in the amount of 0. 1 kg/ton of paper product,
  • - Aqueous Solution 5 comprising sodium hydroxide in the amount of 2 kg/ton of paper product, sodium silicate in the amount of 3 kg/ton of paper product, hydrogen peroxide in the amount of 2 kg/ton of paper product, and a mixture of alkoxylated phosphate ester surfactant, ethoxylated alkyl amine surfactant and ethylene glycol ether in the amount of 0.1 kg/ton of paper product,
  • Aqueous Solution 6 comprising sodium hydroxide in the amount of 2 kg/ton of paper product, sodium silicate in the amount of 3 kg/ton of paper product, hydrogen peroxide in the amount of 2 kg/ton of paper product, and a mixture of alkoxylated phosphate ester surfactant, ethoxylated alkyl amine surfactant and propylene glycol ether in the amount of 0. 1 kg/ton of paper product.
  • the silicone content in paper and pulp will be determined using the applied method based on the standard test method TAPPI T 574-pm04.
  • the method was done by first extracting the paper sample or pulp sample of a certain weight with an organic solvent which can dissolve silicone such as cyclohexane, n- hexane, ethyl acetate, etc., and then evaporating the solvent from the solvent layer containing silicone at the temperature of 105 °C for 2 hours in a pre- weighed container.
  • the silicone content was calculated using the equation below.
  • the moisture content of the sample was obtained by measuring the moisture content of the sample after evaporating moisture by heating in the oven at the temperature of 105 °C for 24 hours.
  • W c is a dry weight of the container and the extracted silicone
  • W t is a dry weight of the container
  • W s is a weight of the sample
  • M is the moisture content of the sample.
  • test results obtained by putting the paper product samples ( A-B) into the deinking and desiliconizing process using the aqueous solution samples 1-6 under the condition specified above are as shown in Tables 1 and 2.
  • Table 1 shows the deinking and desiliconizing efficiencies measured from the resulting pulp from the 1 st flotation.
  • Table 2 shows the deinking and desiliconizing efficiencies measured from the resulting pulp from the 2 nd flotation.
  • the blockage occurred might be because the silicone coated paper contains a high content of long-fiber pulp (i.e. , containing about 50% long- fiber pulp) and because the currently existing process was not designed for applying to the piece of paper with a high content of long- fiber pulp.
  • the use of an excessive proportion of silicone coated paper in the paper product or, in other words, the use of paper product with an excessive content of long-fiber pulp might be the cause of such issue.
  • the process according to the present invention using the aqueous solution samples 3, 4, 5, and 6, that is, the aqueous solution comprising (1) alkylene glycol ether, i.e., propylene glycol ether or ethylene glycol ether, and (2) surfactant, i. e. , alcohol ethoxylate or ethoxylated alkyl amine (Examples 1-4) show a high desiliconizing efficiency of 90-99% while the process using aqueous solution sample without alkylene glycol ether and such surfactant shows a significantly lower desiliconizing efficiency.
  • the process using the aqueous solution sample comprising ethylene glycol ether and ethoxylated alkyl amine surfactant shows a high paper product desiliconizing efficiency of 99%.
  • the overall deinking efficiency of the process according to the present invention is as high as 95-98% (Examples 1-4 in Table 1) and the overall desiliconizing efficiency of the process according to the present invention is high, approximately 90-99% (Examples 1-4 in Table 2).
  • the first step of deinking and desiliconizing by flotation shows the desiliconizing efficiency of over 50%, that is, 54-56% (Examples 1-4 in Table 1) and the second step of deinking and desiliconizing by flotation helped enhance the desiliconizing efficiency to 90-99% (Examples 1-4 in Table 2).
  • the remaining silicone content of the resulting pulp was found to be below 100 ppm which had a technical advantage in that the paper made of the recycled pulp obtained from the deinking and desiliconizing process according to the present invention can be used for printing as equivalent to the common printing and writing paper or the paper made of the recycled pulp obtained by putting the printing and writing paper into the process of the present invention.
  • the paper samples 1-4 were tested by color printing, and the resulting printing qualities were observed.
  • the paper samples used in this test are as follows:
  • paper sample 4 shown in Fig. 1 (d) can be used for continuous color printing, offering smooth colors without leaving any dots or white marks on the printing surface as equivalent to the paper made of the recycled pulp obtained from the paper product sample A that has not undergone the deinking and desiliconizing process according to the present invention (paper sample 1 shown in Fig. 1(a)) and the paper made of the recycled pulp obtained by putting the paper product sample A into the deinking and desiliconizing process according to the present invention (paper sample 3 shown in Fig. 1(c)).
  • paper sample 2 shown in Fig. 1(b) shows non- continuous and uneven color printing with white marks on the paper surface in the printing area.
  • paper sample 4 the paper made of the recycled pulp obtained by putting the paper product sample B into the deinking and desiliconizing process according to the present invention was subject to an additional test in the offset printing and laser toner printing systems by comparing the ink density of the printing material with that of the paper made of the recycled pulp obtained by putting the paper product sample A into the deinking and desiliconizing process according to the present invention (paper sample 3).
  • the test result is shown in Table 3.
  • Table 3 shows the ink density of the paper sample made of pulp obtained from the deinking and desiliconizing process according to the present invention and the paper made of conventional recycled pulp.
  • the paper sample 4 has ink absorption and ink set-off properties similar to the paper sample 3.
  • the paper sample 4 does not have a problem regarding shallow penetration which is similar to the quality of paper sample 3.
  • the similar properties of both paper samples are consistent with the similar ink density as shown in Table 3.
  • the test result above shows that the paper made of the recycled pulp obtained from the deinking and desiliconizing process according to the present invention has the printing properties, in both offset or laser toner printing systems, that are not different from the paper made of conventional recycled pulp obtained by recycling the printing and writing paper (paper product sample A).
  • stiffness index which is the paper stiffness value that is a tensile stiffness ratio measured according to the ISO 5628:1990 standard
  • paper sample 4 the paper made of the recycled pulp obtained from the deinking and desiliconizing process according to the present invention
  • paper sample 4 has the tear index increased by 35%, the tensile index increased by 28% and the density increased by 15% compared with the paper made of conventional recycled pulp (paper sample 3, (a)) as shown in Fig. 2.
  • Such improved physical properties may be because the recycled pulp obtained according to the present invention was obtained by using the paper product comprising silicone coated paper with 50% long- fiber pulp.
  • the paper product comprising silicone coated paper with 50% long- fiber pulp.

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)

Abstract

The present invention relates to a process for deinking and desiliconizing paper product comprising the steps of (i) pulp screening and treating the paper product using an aqueous solution comprising alkylene glycol ether, sodium hydroxide, sodium silicate, hydrogen peroxide, and surfactant to obtain a slurry of the treated pulp, and (ii) removing ink and silicone from the slurry of the treated pulp of step (i).

Description

PROCESS FOR DEINKING AND DESILICONIZING PAPER PRODUCT
TECHNICAL FIELD
Chemistry related to a process for deinking and desiliconizing paper product
BACKGROUND OF THE INVENTION
Currently, the used paper that contains contaminants such as printing ink will be recycled to remove the ink, and then the recycled pulp obtained will be reused for paper production. However, there is no method that can efficiently remove or separate the contaminants, especially silicone coatings, from the printing and writing paper using an existing deinking process since the printing and writing paper deinking process was designed for extracting ink from the printing and writing paper only. Thus, the used silicone coated paper or siliconized glassine paper are usually disposed, for example, by means of incineration or landfill, which will subsequently cause environmental problems.
A recycling method for separating or removing silicone from the paper by optimizing the conditions of the existing printing and writing paper deinking process is a low- cost method since this can be done using devices or machines existing in the printing and writing paper deinking process and can help solve the paper waste management problems and environmental problems by reusing the recycled pulp as a raw material in the paper production.
Due to the above reasons, there remains a need to invent and develop the effective methods or processes for desiliconizing and deinking the paper. Examples of the prior art related to the methods or processes for deinking and/or desiliconizing the substrate or paper are as follows.
US 5,634,405 discloses a method for deinking the substrate comprising thermoplastic resin. Such method comprises contacting the substrate with an aqueous solution of glycol ether for a sufficient period of time under an effective condition.
US 5,567,272 discloses a process for recycling silicone coated paper by using monophosphoric ester salt. Such process comprises a step of pulping using a disintegrator under the basic pH of 10- 12 and at the temperature ranging from 60- 80 °C with one or more types of monophosphoric ester salt, and a step of paper sheet reformation.
US 1,628,931 discloses a method of recycling waxed paper using trisodiumphosphate in the basic environment. Such recycling method can be used to remove wax and ink from the paper at the same time. However, though the prior arts above disclose the methods of deinking and/ or desiliconizing the paper, there is still a need to invent and develop the highly effective methods of deinking and desiliconizing the paper product that can be applied to the existing printing and writing paper deinking process, and that yields the recycled pulp with no silicone or minimum amount of silicone left which does not negatively affect the properties of pulp or paper made of the recycled pulp in application e.g., strength, printing quality, etc.
SUMMARY OF THE INVENTION
The objective of the present invention is to provide a process for deinking and desiliconizing paper product using chemicals in conjunction with adjustment the conditions of the existing deinking processes for printing and writing paper so that the invented process can be used for recycling the silicone coated paper or siliconized glassine paper in a highly effective manner, and to obtain the recycled pulp with the minimum amount of contaminants, particularly silicone, preferably less than 100 ppm, which will not affect the properties of pulp or paper made of such recycled pulp, especially the strength and printing properties.
In one aspect, the present invention relates to a process for deinking and desiliconizing paper product comprising the steps of:
(i) pulp screening and treating the paper product using an aqueous solution comprising alkylene glycol ether, sodium hydroxide, sodium silicate, hydrogen peroxide, and surfactant to obtain a slurry of the treated pulp, and
(ii) removing ink and silicone from the slurry of the treated pulp of step (i).
In another aspect, the present invention also relates to the recycled pulp obtained from the process for deinking and desiliconizing paper product according to the present invention, as well as the paper made of such recycled pulp.
The process for deinking and desiliconizing paper product according to the present invention provides a high deinking efficiency of 95-98% and a high siliconizing efficiency of about 90-99%. Furthermore, the paper made of the recycled pulp obtained from the deinking and desiliconizing process according to the present invention has better physical properties e. g. , strength and density than those of paper made of the conventional recycled pulp and can also be used for printing.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an example of color printing on paper samples, i.e., (a) a paper sample which is made of the recycled pulp obtained from the printing and writing paper that has not undergone the deinking and desiliconizing process according to the present invention, (b) a paper sample which is made of the recycled pulp obtained from the paper product sample comprising the printing and writing paper and silicone coated paper that have not undergone the deinking and desiliconizing process according to the present invention, (c) a paper sample which is made of the recycled pulp obtained by putting the printing and writing paper into the deinking and desiliconizing process according to the present invention, and (d) a paper sample which is made of the recycled pulp obtained by putting the paper product sample comprising the printing and writing paper and silicone coated paper into the deinking and desiliconizing process according to the present invention.
Fig. 2 is a graph that shows a comparison of physical properties of (a) a paper made of recycled pulp obtained from the conventional deinking process and (b) a paper made of the recycled pulp obtained from the deinking and desiliconizing process according to the present invention.
DETAILED DESCRIPTION
Any aspects shown herein shall encompass the application to other aspects of the present invention as well, unless specified otherwise.
Unless specified otherwise, technical and scientific terms used herein have meanings as understood by a person skilled in the art.
The terms “consist(s) of”, “comprise(s)”, “contain(s)” and “include(s)” are open-ended verbs. For example, any methods “consisting of”, “comprising”, “containing” or “including” one or more components or one or more steps are not limited to said one or more components or one or more steps but also encompass components or steps that are not specified.
Any tools, equipment, methods, materials, or chemicals mentioned herein, unless specified otherwise, mean the tools, equipment, methods, materials, or chemicals generally used or practiced by a person skilled in the art.
Process for deinking and desiliconizing paper product
The process for deinking and desiliconizing paper product comprising the steps of:
(i) pulp screening and treating the paper product using an aqueous solution comprising alkylene glycol ether, sodium hydroxide, sodium silicate, hydrogen peroxide, and surfactant to obtain a slurry of the treated pulp, and
(ii) removing ink and silicone from the slurry of the treated pulp of step (i).
The term “paper product” as used herein, is meant to encompass used paper, piece of paper or paper waste. The paper product that can be used in the deinking and desiliconizing process according to the present invention may be used paper of any types such as the printing and writing paper, silicone coated paper, siliconized glassine paper or a mixture thereof. Preferably, the paper product for the deinking and desiliconizing process according to the present invention is a mixture of a used printing and writing paper and a used silicone coated paper.
In one aspect of the present invention, the silicone coated paper includes the siliconized glassine paper.
A ratio of the printing and writing paper to the silicone coated paper used in the deinking and desiliconizing process according to the present invention is in a range of 75- 99: 1- 25, preferably in a range of 75-90:10-25, more preferably 80:20.
Step (i) Pulp Screening and Paper Product Treatment
According to a preferred embodiment of the present invention, the aqueous solution used in step (i) is a mixed solution of alkylene glycol ether, sodium hydroxide, sodium silicate, hydrogen peroxide, and surfactant in water.
In particular, such aqueous solution comprises alkylene glycol ether in an amount ranging from 0.1-1 wt% based on the weight of silicone coated paper.
The alkylene glycol ether may be selected from a group consisting of ethylene glycol ether, propylene glycol ether, and a mixture thereof. Preferably, the alkylene glycol ether is ethylene glycol ether.
In particular, the aqueous solution comprises sodium hydroxide in an amount ranging from 1-5 kg/ton of paper product.
In particular, the aqueous solution comprises sodium silicate in an amount ranging from 1 -5 kg/ton of paper product.
In particular, the aqueous solution comprises hydrogen peroxide in an amount ranging from 1-4 kg/ton of paper product.
According to the present invention, the surfactant is a nonionic surfactant, whereby the nonionic surfactant can be selected from a group consisting of alcohol alkoxylate, alcohol ethoxylate, and a mixture thereof.
The nonionic surfactant can be selected from a group consisting of alkoxylated phosphate ester, ethoxylated alkyl amine, and a mixture thereof. Preferably, the nonionic surfactant is a mixture of alkoxylated phosphate ester and ethoxylated alkyl amine.
More preferably, the surfactant according to the present invention comprises alkoxylated phosphate ester in an amount ranging from 0.1-1 kg/ton of printing and writing paper. Still more preferably, the surfactant according to the present invention comprises ethoxylated alkyl amine in an amount ranging from 0.01- 0. 1 wt% based on the weight of silicone coated paper.
According to the present invention, the pulp fractionation and paper product treatment in step (i) are performed by using a mechanical treatment in conjunction with a chemical treatment at a temperature ranging from 50- 60 °C , pH ranging from 9- 11, for 15-30 minutes, more preferably 25-30 minutes.
In this regard, the slurry of the treated pulp of step (i) has a consistency ranging from 12-17%.
Step (ii) Removal of Ink and Silicone
According to the present invention, the removal of ink and silicone from the pulp slurry in step (ii) is performed by means of screening, centrifugation, or flotation.
Preferably, the removal of ink and silicone from the pulp slurry in step (ii) is performed by means of flotation comprising passing the slurry of the treated pulp of step (i) into a flotation apparatus/system or a flotation cell which contains a mechanical mechanism for producing many air bubbles. Thereby, the ink and silicone particles which are hydrophobic will attach to the air bubbles formed and float to the top surface of aqueous solution. Then, such bubbles with the ink and silicone particles attached will be separated and transferred for disposal, e. g. , by means of incineration to produce heat energy at a boiler.
In particular, the removal of ink and silicone from the pulp slurry in step (ii) is performed by means of flotation at a temperature ranging from 50-60 °C, under an air pressure ranging from 30-40 kPa.
Furthermore, the removal of ink and silicone from the pulp slurry in step (ii) may comprise ensuring the slurry of the treated pulp of step (i) has a consistency of 1% prior to flotation.
In this regard, such removal of ink and silicone by flotation may be performed only once or may be repeated multiple times.
In one aspect, the removal of ink and silicone from the pulp slurry in step (ii) is performed by applying flotation twice.
In particular, the second flotation is applied at the temperature ranging from 50- 60 °C , under the air pressure ranging from 10-20 kPa.
In a further aspect of the invention, the removal of ink and silicone from the pulp slurry in step (ii) may further comprise a size reduction and dispersion of ink, silicone, and other contaminants which are carried out after the first flotation. Preferably, the size reduction and dispersion of ink, silicone, and other contaminants are carried out by means of a mechanical treatment at a temperature ranging from 100- 120 °C, by intensive kneading with a specific energy consumption (SEC) ranging from 100-130 kWh/ton of paper product. However, the SEC used for the size reduction and dispersion of ink can be optimized based on the initial pulp freeness. For example, the SEC used in intensive kneading can be increased up to 150 kWh/ton of initial paper product sample.
The deinking and desiliconizing process of this invention may further comprise soaking the paper product in an aqueous solution at a temperature ranging from 50-60 °C, pH ranging from 9-11, for 15-30 minutes before proceeding to step (i).
As described above, the removal of ink and silicone from the pulp slurry in step (ii) that is performed by means of flotation can be performed in many ways. For example:
In one embodiment, the removal of ink and silicone from the pulp slurry in step (ii) comprises applying flotation only once.
In another embodiment, the removal of ink and silicone from the pulp slurry in step (ii) comprises the first flotation and the second flotation, respectively.
In a preferred embodiment, the removal of ink and silicone from the pulp slurry in step (ii) comprises the first flotation, the size reduction and dispersion of ink, silicone, and other contaminants, and the second flotation, respectively.
In another preferred embodiment, the removal of ink and silicone from the pulp slurry in step (ii) comprises soaking the paper product in the aqueous solution with components of the type and in the amount as specified above, the first flotation, the size reduction and dispersion of ink, silicone, and other contaminants and the second flotation, respectively.
In this regard, the conditions applied in the operation of the removal of ink and silicone from the pulp slurry in step (ii) in the above embodiments are as previously specified.
The exemplary embodiments of the present invention will now be described in more detail with reference to the examples, test results, and appended drawings. In any case, the examples exhibited herein are not intended to limit the scope of the present invention.
Example
1. Deinking and Desiliconizing Process
To study the effect of steps and factors such as the ratio of the printing and writing paper to the silicone coated paper, types of the surfactant and ethylene glycol ether used in the process on the paper product deinking and siliconizing efficiencies, the paper product sample that contains the used printing and writing paper and the used silicone coated paper was deinked and desiliconized using the process of which the steps and details are as follows:
1) soaking the paper product sample in the previously prepared aqueous solution under the condition with the temperature ranging from 50- 60 °C and pH ranging from 9- 11 for 30 minutes,
2) pulping with the disintegrator in the aqueous solution under the temperature ranging from 50- 60 °C and pH ranging from 9- 11 for 25- 30 minutes to obtain the pulp stock that is the slurry with a consistency in a range of 12-17%,
3) screening large dirt, scrap, or piece of paper by passing the pulp slurry to a sieve,
4) ensuring the screened pulp above has a consistency of 1% by diluting it with water,
5) passing the pulp slurry to the flotation cell for the first deinking and desiliconizing flotation under the temperature ranging from 50-60 °C and the air pressure ranging from 30-40 kPa,
6) carrying out the size reduction and dispersion of ink, silicone, and other contaminants by grinding with a specific energy consumption (SEC) ranging from 100-130 kWh/ton of initial paper product sample under the temperature ranging from 100-120 °C, and
7) passing the pulp slurry that had been subject to the size reduction and dispersion of ink, silicone, and other contaminants to the flotation cell for the second deinking and desiliconizing flotation under the temperature ranging from 50-60 °C and the air pressure ranging from 10-20 kPa.
The size of bubbles formed in the flotation cell of the second deinking and desiliconizing flotation would be smaller than those formed in the flotation cell of the first deinking and desiliconizing flotation, allowing better performance of the pulp deinking and desiliconizing process.
During performing the steps as specified above, the amount of ink and silicone contained in the pulp before and after the first and second flotations was measured for comparison of deinking and desiliconizing efficiencies of the process.
The process specified above was done using the paper product and aqueous solution samples as follows.
1. Paper product samples are:
- Paper Product Sample A of which the raw material is the used printing and writing paper,
- Paper Product Sample B which is a mixture of 80% used printing and writing paper and 20% used silicone coated paper, - Paper Product Sample C which is a mixture of 70% used printing and writing paper and 30% used silicone coated paper.
The silicone coated paper used in this test comprises approximately 50% long- fiber pulp and approximately 50% short-fiber pulp.
2. Aqueous solution samples are:
- Aqueous Solution 1 comprising sodium hydroxide in the amount of 2 kg/ ton of paper product, sodium silicate in the amount of 3 kg/ ton of paper product, hydrogen peroxide in the amount of 2 kg/ton of paper product, and alkoxylated phosphate ester surfactant in the amount of 0.1 kg/ton of paper product,
- Aqueous Solution 2 comprising sodium hydroxide in the amount of 2 kg/ton of paper product, sodium silicate in the amount of 3 kg/ton of paper product, hydrogen peroxide in the amount of 2 kg/ton of paper product, and fatty alcohol alkoxylate surfactant in the amount of 0.1 kg/ton of paper product,
- Aqueous Solution 3 comprising sodium hydroxide in the amount of 2 kg/ton of paper product, sodium silicate in the amount of 3 kg/ton of paper product, hydrogen peroxide in the amount of 2 kg/ton of paper product, and a mixture of alkoxylated phosphate ester surfactant, alcohol ethoxylate surfactant and propylene glycol ether in the amount of 0. 1 kg/ton of paper product,
- Aqueous Solution 4 comprising sodium hydroxide in the amount of 2 kg/ton of paper product, sodium silicate in the amount of 3 kg/ton of paper product, hydrogen peroxide in the amount of 2 kg/ton of paper product, and a mixture of alkoxylated phosphate ester surfactant, alcohol ethoxylate surfactant and ethylene glycol ether in the amount of 0. 1 kg/ton of paper product,
- Aqueous Solution 5 comprising sodium hydroxide in the amount of 2 kg/ton of paper product, sodium silicate in the amount of 3 kg/ton of paper product, hydrogen peroxide in the amount of 2 kg/ton of paper product, and a mixture of alkoxylated phosphate ester surfactant, ethoxylated alkyl amine surfactant and ethylene glycol ether in the amount of 0.1 kg/ton of paper product,
- Aqueous Solution 6 comprising sodium hydroxide in the amount of 2 kg/ton of paper product, sodium silicate in the amount of 3 kg/ton of paper product, hydrogen peroxide in the amount of 2 kg/ton of paper product, and a mixture of alkoxylated phosphate ester surfactant, ethoxylated alkyl amine surfactant and propylene glycol ether in the amount of 0. 1 kg/ton of paper product. 2. Method of Determining Silicone Content in Paper and Pulp
According to the present invention, the silicone content in paper and pulp will be determined using the applied method based on the standard test method TAPPI T 574-pm04. The method was done by first extracting the paper sample or pulp sample of a certain weight with an organic solvent which can dissolve silicone such as cyclohexane, n- hexane, ethyl acetate, etc., and then evaporating the solvent from the solvent layer containing silicone at the temperature of 105 °C for 2 hours in a pre- weighed container. The silicone content was calculated using the equation below. The moisture content of the sample was obtained by measuring the moisture content of the sample after evaporating moisture by heating in the oven at the temperature of 105 °C for 24 hours.
Figure imgf000011_0001
wherein:
Wc is a dry weight of the container and the extracted silicone,
Wt is a dry weight of the container,
Ws is a weight of the sample, and
M is the moisture content of the sample.
3. Test Results
The test results obtained by putting the paper product samples ( A-B) into the deinking and desiliconizing process using the aqueous solution samples 1-6 under the condition specified above are as shown in Tables 1 and 2.
Table 1 shows the deinking and desiliconizing efficiencies measured from the resulting pulp from the 1st flotation.
Figure imgf000011_0002
Figure imgf000012_0001
Table 2 shows the deinking and desiliconizing efficiencies measured from the resulting pulp from the 2nd flotation.
Figure imgf000012_0002
3.1 Effect of the ratios of the printing and writing paper to the silicone coated paper From the test result on the comparison of 3 types of paper product sample: paper product sample A (100% printing and writing paper), paper product sample B (80% printing and writing paper and 20% silicone coated paper), and paper product sample C (70% printing and writing paper and 30% silicone coated paper), it was found that the ratio of the printing and writing paper to the silicone coated paper that is suitable for use in the process according to the present invention is 80% printing and writing paper to 20% silicone coated paper. When increasing the silicone coated paper content to 30% (paper product sample C), a blockage was found in the screening area before the first flotation, leading to a large difference between the input and output pressure in the system and an interruption of operation for cleaning the clogged area. This not only resulted in difficulties in the operation, but also resulted in the loss of chance due to the lower productivity. In this regard, the blockage occurred might be because the silicone coated paper contains a high content of long-fiber pulp (i.e. , containing about 50% long- fiber pulp) and because the currently existing process was not designed for applying to the piece of paper with a high content of long- fiber pulp. Thus, the use of an excessive proportion of silicone coated paper in the paper product or, in other words, the use of paper product with an excessive content of long-fiber pulp might be the cause of such issue.
3. 2 Effect of the surfactants and alkylene glycol ether on the deinking and desiliconizing efficiencies
From the test result in Table 1, it was found that the process according to the present invention shows a high deinking efficiency of 95- 98% since the first flotation (Examples 1-4) . The process using the aqueous solution sample comprising ethoxylated alkyl amine surfactant and ethylene glycol ether ( aqueous solution 5, Example 3) shows a high deinking efficiency of 98%.
Furthermore, from the test results in Table 2, it was also found that the process according to the present invention using the aqueous solution samples 3, 4, 5, and 6, that is, the aqueous solution comprising (1) alkylene glycol ether, i.e., propylene glycol ether or ethylene glycol ether, and (2) surfactant, i. e. , alcohol ethoxylate or ethoxylated alkyl amine (Examples 1-4) show a high desiliconizing efficiency of 90-99% while the process using aqueous solution sample without alkylene glycol ether and such surfactant shows a significantly lower desiliconizing efficiency. The process using the aqueous solution sample comprising ethylene glycol ether and ethoxylated alkyl amine surfactant (aqueous solution 5, Example 3) shows a high paper product desiliconizing efficiency of 99%.
3.3 Effect of flotation on the deinking and desiliconizing efficiencies
From the test result, it was found that the overall deinking efficiency of the process according to the present invention is as high as 95-98% (Examples 1-4 in Table 1) and the overall desiliconizing efficiency of the process according to the present invention is high, approximately 90-99% (Examples 1-4 in Table 2). The first step of deinking and desiliconizing by flotation shows the desiliconizing efficiency of over 50%, that is, 54-56% (Examples 1-4 in Table 1) and the second step of deinking and desiliconizing by flotation helped enhance the desiliconizing efficiency to 90-99% (Examples 1-4 in Table 2).
3. 4 Pulp obtained from the process for deinking and desiliconizing paper product according to the present invention and paper made of said pulp
3.4.1 The remaining silicone content and its effect on printing
When measuring the remaining silicone content in the pulp obtained from the deinking and desiliconizing process according to the present invention by using the method according to Thai patent application publication no. 162174, the method of determining the inconsistency in printing, the remaining silicone content of the resulting pulp was found to be below 100 ppm which had a technical advantage in that the paper made of the recycled pulp obtained from the deinking and desiliconizing process according to the present invention can be used for printing as equivalent to the common printing and writing paper or the paper made of the recycled pulp obtained by putting the printing and writing paper into the process of the present invention.
According to this test, the paper samples 1-4 were tested by color printing, and the resulting printing qualities were observed. The paper samples used in this test are as follows:
- Paper Sample 1 which is made of the recycled pulp obtained from the paper product sample A that has not undergone the deinking and desiliconizing process according to the present invention,
- Paper Sample 2 which is paper made of the recycled pulp obtained from the paper product sample B that has not undergone the deinking and desiliconizing process according to the present invention,
- Paper Sample 3 which is paper made of the recycled pulp obtained by putting the paper product sample A into the deinking and desiliconizing process according to the present invention,
- Paper Sample 4 which is paper made of the recycled pulp obtained by putting the paper product sample B into the deinking and desiliconizing process according to the present invention.
From the test result shown in Fig. 1, it can be seen that the paper made of the recycled pulp obtained by putting the paper product sample B into the deinking and desiliconizing process according to the present invention (paper sample 4 shown in Fig. 1 (d)) can be used for continuous color printing, offering smooth colors without leaving any dots or white marks on the printing surface as equivalent to the paper made of the recycled pulp obtained from the paper product sample A that has not undergone the deinking and desiliconizing process according to the present invention (paper sample 1 shown in Fig. 1(a)) and the paper made of the recycled pulp obtained by putting the paper product sample A into the deinking and desiliconizing process according to the present invention (paper sample 3 shown in Fig. 1(c)). On the contrary, the paper made of the recycled pulp obtained from the paper product sample B that has not undergone the deinking and desiliconizing process of this invention (paper sample 2 shown in Fig. 1(b) ) shows non- continuous and uneven color printing with white marks on the paper surface in the printing area.
In addition, the paper made of the recycled pulp obtained by putting the paper product sample B into the deinking and desiliconizing process according to the present invention (paper sample 4) was subject to an additional test in the offset printing and laser toner printing systems by comparing the ink density of the printing material with that of the paper made of the recycled pulp obtained by putting the paper product sample A into the deinking and desiliconizing process according to the present invention (paper sample 3). The test result is shown in Table 3.
Table 3 shows the ink density of the paper sample made of pulp obtained from the deinking and desiliconizing process according to the present invention and the paper made of conventional recycled pulp.
Figure imgf000015_0001
From the test result, it has been found that the paper sample 4 has ink absorption and ink set-off properties similar to the paper sample 3. For the test with the laser toner printing system, it was also found that the paper sample 4 does not have a problem regarding shallow penetration which is similar to the quality of paper sample 3. The similar properties of both paper samples are consistent with the similar ink density as shown in Table 3.
Thus, the test result above shows that the paper made of the recycled pulp obtained from the deinking and desiliconizing process according to the present invention has the printing properties, in both offset or laser toner printing systems, that are not different from the paper made of conventional recycled pulp obtained by recycling the printing and writing paper (paper product sample A).
3.4.2 Physical properties
The paper samples were subject to an additional measurement of physical properties as follows:
- the tear index which is the tear strength relative to paper weight measured according to the ISO 1974:2012 standard,
- the tensile index which is the tensile strength relative to paper weight measured according to the ISO 1924-2:2008 standard,
- the stiffness index which is the paper stiffness value that is a tensile stiffness ratio measured according to the ISO 5628:1990 standard,
- the density which is the paper weight per volume measured according to the ISO 534:2011 standard,
- the stretch of paper measured according to the ISO 1924-2:2008 standard. From the test results, it was found that the paper made of the recycled pulp obtained from the deinking and desiliconizing process according to the present invention (paper sample 4, (b)) has the tear index increased by 35%, the tensile index increased by 28% and the density increased by 15% compared with the paper made of conventional recycled pulp (paper sample 3, (a)) as shown in Fig. 2.
Such improved physical properties may be because the recycled pulp obtained according to the present invention was obtained by using the paper product comprising silicone coated paper with 50% long- fiber pulp. Thus, by putting such silicone coated paper into the deinking and desiliconizing process according to the present invention together with the common printing and writing paper with short-fiber pulp, the physical advantage mentioned above can be achieved.
All the test results above show that the deinking and desiliconizing process according to the present invention have the high deinking and desiliconizing efficiencies, and that the paper made of pulp obtained from the deinking and desiliconizing process according to the present invention exhibits good physical properties and it is suitable for printing.
The process and steps disclosed and claimed in the present invention are intended to encompass the aspects of the invention derived by conducting, practicing, modifying or altering any factors without conducting any test that is significantly different from the present invention, and obtaining things which has properties, usefulness and effects similar to those of the aspects of the present invention according to the opinion of those of ordinary skill in the art, even though it is not specifically stated in the claims. Thus, the equivalents or the analogues of the aspects of the present invention including any minor modification or alteration that is clearly apparent to the person of ordinary skill in the art shall be deemed to be within the spirit, scope, and concept of the present invention as well.
BEST MODE OF THE INVENTION
Best mode of the invention is as described in the detailed description of the invention.

Claims

WHAT IS CLAIMED IS:
1. A process for deinking and desiliconizing paper product comprising the steps of:
(i) pulp screening and treating the paper product using an aqueous solution comprising alkylene glycol ether, sodium hydroxide, sodium silicate, hydrogen peroxide, and surfactant to obtain a slurry of the treated pulp, and
(ii) removing ink and silicone from the slurry of the treated pulp of step (i).
2. The process according to claim 1 , wherein the paper product is a mixture of a used printing and writing paper and a used silicone coated paper.
3. The process according to claim 2, wherein a ratio of the printing and writing paper to the silicone coated paper is in a range of 75-99:1-25.
4. The process according to claim 3, wherein the ratio of the printing and writing paper to the silicone coated paper is in a range of 75-90:10-25.
5. The process according to claim 4, wherein the ratio of the printing and writing paper to the silicone coated paper is 80:20.
6. The process according to any one of claims 1-5, wherein an amount of alkylene glycol ether is in a range of 0. 1- 1 wt% based on the weight of silicone coated paper.
7. The process according to claim 6, wherein the alkylene glycol ether is selected from a group consisting of ethylene glycol ether, propylene glycol ether, and a mixture thereof.
8. The process according to claim 7, wherein the alkylene glycol ether is ethylene glycol ether.
9. The process according to any one of claims 1-5, wherein an amount of sodium hydroxide is in a range of 1-5 kg/ton of paper product.
10. The process according to any one of claims 1-5, wherein an amount of sodium silicate is in a range of 1-5 kg/ton of paper product.
11. The process according to any one of claims 1-5, wherein an amount of hydrogen peroxide is in a range of 1-4 kg/ton of paper product.
12. The process according to any one of claims 1- 5, wherein the surfactant is a nonionic surfactant.
13. The process according to claim 12, wherein the nonionic surfactant is selected from a group consisting of alcohol alkoxylate, alcohol ethoxylate, and a mixture thereof.
14. The process according to claim 13, wherein the nonionic surfactant is selected from a group consisting of alkoxylated phosphate ester, ethoxylated alkyl amine, and a mixture thereof.
15. The process according to claim 14, wherein the nonionic surfactant is a mixture of alkoxylated phosphate ester and ethoxylated alkyl amine.
16. The process according to claim 14 or 15, wherein an amount of alkoxylated phosphate ester is in a range of 0.1 -1 kg/ton of printing and writing paper.
17. The process according to claim 14 or 15, wherein an amount of ethoxylated alkyl amine is in a range of 0.01-0.1 wt% based on the weight of silicone coated paper.
18. The process according to any one of claims 1- 17, wherein the pulp screening and the paper product treatment in step (i) are performed by using a mechanical treatment in conjunction with a chemical treatment at a temperature ranging from 50-60 °C, pH ranging from 9-11, for 15-30 minutes.
19. The process according to claim 18, wherein the pulp screening and the paper product treatment in step (i) are performed by using the mechanical treatment in conjunction with the chemical treatment at the temperature ranging from 50- 60 °C, pH ranging from 9-11, for 25-30 minutes.
20. The process according to any one of claims 1-19, wherein the slurry of the treated pulp of step (i) has a consistency ranging from 12-17%.
21. The process according to claim 1, wherein the removal of ink and silicone from the pulp slurry in step (ii) is performed by means of screening, centrifugation, or flotation.
22. The process according to claim 21, wherein the removal of ink and silicone from the pulp slurry in step (ii) is performed by means of flotation at a temperature ranging from 50-60 °C, under an air pressure ranging from 30-40 kPa.
23. The process according to claim 22, wherein the removal of ink and silicone from the pulp slurry in step (ii) comprising ensuring the slurry of the treated pulp of step (i) has a consistency of 1% prior to flotation.
24. The process according to any one of claims 21-23, wherein the removal of ink and silicone from the pulp slurry in step (ii) is performed by applying flotation twice.
25. The process according to claim 24, wherein the second flotation is applied at the temperature ranging from 50-60 °C, under the air pressure ranging from 10-20 kPa.
26. The process according to claim 24, wherein the removal of ink and silicone from the pulp slurry in step (ii) further comprising a size reduction and hot dispersion of ink, silicone, and other contaminants which are carried out after the first flotation.
27. The process according to claim 26, wherein the size reduction and hot dispersion of ink, silicone, and other contaminants are carried out by means of a mechanical treatment at a temperature ranging from 100- 120 °C, by intensive kneading with a specific energy consumption (SEC) ranging from 100- 130 kWh/ ton of paper product.
28. The process according to any one of claims 1-27, further comprising soaking the paper product in an aqueous solution at a temperature ranging from 50-60 °C, pH ranging from 9-11, for 15-30 minutes before proceeding to step (i).
PCT/TH2021/000064 2020-10-20 2021-10-18 Process for deinking and desiliconizing paper product WO2022086456A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
TH2001006094 2020-10-20
TH2001006094A TH2001006094A (en) 2020-10-20 The process of removing ink and silicone from paper products.

Publications (1)

Publication Number Publication Date
WO2022086456A1 true WO2022086456A1 (en) 2022-04-28

Family

ID=81290941

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/TH2021/000064 WO2022086456A1 (en) 2020-10-20 2021-10-18 Process for deinking and desiliconizing paper product

Country Status (1)

Country Link
WO (1) WO2022086456A1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4548674A (en) * 1983-08-08 1985-10-22 Interox (Societe Anonyme) Process for the regeneration of waste paper
US5314580A (en) * 1992-07-08 1994-05-24 Mauvin Material & Chemical Processing Limited Process for the removal of ink, resin, and adhesive residues from paper, textile fabrics and solid surfaces
US5316621A (en) * 1990-10-19 1994-05-31 Kanzaki Paper Mfg. Co., Ltd. Method of pulping waste pressure-sensitive adhesive paper
JPH07145582A (en) * 1993-11-22 1995-06-06 Honshu Paper Co Ltd Production of deinked pulp
CN106065541A (en) * 2016-08-04 2016-11-02 湖北金民纤维材料科技有限公司 A kind of wastepaper deinking agent and preparation technology

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4548674A (en) * 1983-08-08 1985-10-22 Interox (Societe Anonyme) Process for the regeneration of waste paper
US5316621A (en) * 1990-10-19 1994-05-31 Kanzaki Paper Mfg. Co., Ltd. Method of pulping waste pressure-sensitive adhesive paper
US5314580A (en) * 1992-07-08 1994-05-24 Mauvin Material & Chemical Processing Limited Process for the removal of ink, resin, and adhesive residues from paper, textile fabrics and solid surfaces
JPH07145582A (en) * 1993-11-22 1995-06-06 Honshu Paper Co Ltd Production of deinked pulp
CN106065541A (en) * 2016-08-04 2016-11-02 湖北金民纤维材料科技有限公司 A kind of wastepaper deinking agent and preparation technology

Similar Documents

Publication Publication Date Title
CA2532584C (en) Methods for producing recycled pulp, methods for modifying pulp fibre surfaces and dirts, as well as pulp processing equipments
EP2400054B1 (en) A method for treating process waters by cavitation
JP4854733B2 (en) Removal of organic deposits from recycled fibers used to produce paper
US8657995B2 (en) Method of producing recycled paper pulp from waste printed paper as raw material
JP2761608B2 (en) How to deink waste paper material
JP2013519804A (en) How to remove ink from paper
US5895556A (en) Waste paper treatment process
CA2681140C (en) Method of deinking recovered paper
WO2010093220A3 (en) Method for manufacturing tissue using recovered paper from corrugated fiberboard as raw material
WO2022086456A1 (en) Process for deinking and desiliconizing paper product
WO1996008598A1 (en) Deinking composition and method for deinking waste paper
JPH05209383A (en) Method for pulping pressure-sensitive adhesive waste paper
CN101115879A (en) Method for beating pulp
JP6443290B2 (en) Method for producing deinked waste paper pulp
WO2019113410A1 (en) Removal of stickies in the recycling of paper and paperboard
Seo et al. Effect of fatty acid and non-ionic surfactant on the deinkability of mixed recovered paper
JPH04209880A (en) Method for pulping waste release paper
JP2004019025A (en) Method for producing deinked pulp and method for producing regenerated paper
JP2005240188A (en) Method for producing waste paper pulp and waste paper pulp
JP2010100984A (en) Method for deinking printed waste paper
JPH05163689A (en) Pulping method for pressure-sensitive adhesive waste paper
KR100238107B1 (en) A manufacturing method of recycling pulp
KR100217303B1 (en) The production of high brightness recycled pulp
KR20220061314A (en) Tissue manufacturing system using old corrugated container and used paper and tissue manufacturing method using the same
JP2017066570A (en) Deinking agent for floatation and manufacturing method of recycled pulp

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21883439

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21883439

Country of ref document: EP

Kind code of ref document: A1