WO2022094735A1 - Paper impregnation method with antimicrobial effect, for covering wooden boards - Google Patents

Paper impregnation method with antimicrobial effect, for covering wooden boards Download PDF

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Publication number
WO2022094735A1
WO2022094735A1 PCT/CL2020/050189 CL2020050189W WO2022094735A1 WO 2022094735 A1 WO2022094735 A1 WO 2022094735A1 CL 2020050189 W CL2020050189 W CL 2020050189W WO 2022094735 A1 WO2022094735 A1 WO 2022094735A1
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Prior art keywords
paper
impregnation
resin
mixture
impregnation process
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PCT/CL2020/050189
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Spanish (es)
French (fr)
Inventor
Bruno GORRINI BELMAR
Simón PARDO HOLTHEUER
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Investigaciones Forestales Bioforest S.A.
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Publication of WO2022094735A1 publication Critical patent/WO2022094735A1/en

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    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N25/00—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N25/00—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
    • A01N25/22—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests containing ingredients stabilising the active ingredients
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N25/00—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
    • A01N25/34—Shaped forms, e.g. sheets, not provided for in any other sub-group of this main group
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N55/00—Biocides, pest repellants or attractants, or plant growth regulators, containing organic compounds containing elements other than carbon, hydrogen, halogen, oxygen, nitrogen and sulfur
    • A01N55/02—Biocides, pest repellants or attractants, or plant growth regulators, containing organic compounds containing elements other than carbon, hydrogen, halogen, oxygen, nitrogen and sulfur containing metal atoms
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N59/00—Biocides, pest repellants or attractants, or plant growth regulators containing elements or inorganic compounds
    • A01N59/16—Heavy metals; Compounds thereof
    • A01N59/20—Copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B29/00—Layered products comprising a layer of paper or cardboard
    • B32B29/06—Layered products comprising a layer of paper or cardboard specially treated, e.g. surfaced, parchmentised
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
    • C08J7/04—Coating
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H19/00—Coated paper; Coating material
    • D21H19/02—Metal coatings
    • D21H19/06—Metal coatings applied as liquid or powder
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H19/00—Coated paper; Coating material
    • D21H19/36—Coatings with pigments
    • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
    • D21H19/56—Macromolecular organic compounds or oligomers thereof obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H19/58—Polymers or oligomers of diolefins, aromatic vinyl monomers or unsaturated acids or derivatives thereof
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
    • D21H21/36—Biocidal agents, e.g. fungicidal, bactericidal, insecticidal agents

Definitions

  • the present invention is related to the application of antimicrobial compounds that comprise copper nanoparticles (Cu NPs), these being added to the paper impregnation process with amino resins (urea-formaldehyde (UF), melamine-formaldehyde (MF), melamine -urea-formaldehyde (MUF)), for the coating of wooden boards.
  • Cu NPs copper nanoparticles
  • the resulting product comprises a melamine-coated wood-based board that has high antimicrobial effectiveness.
  • the paper is impregnated with urea and melamine resins, using a partial polymerization process.
  • the paper rolls are loaded into the unwinding machine and fed through a series of rollers into one or more impregnation baths, where there is a mixture of resins in addition to other impregnation additives.
  • the previous mixture of resin and impregnation additives is soaked in the paper, which must then be dried in ovens at a carefully controlled temperature depending on the speed.
  • the finished product dry impregnated paper
  • the finished product is automatically cut to the required size (dry impregnated paper sheets) for the wood board melamine process.
  • the stacked sheets are stored in racks, where with the help of the anti-blocking agent (part of the rest of the impregnation additives) the sheets are prevented from sticking together.
  • Impregnation additives refer to chemical compounds, such as anti-dust, humectants, anti-blocking, release agents, etc., that i they are incorporated into the process of applying ammica resins in said papers, which confer properties both to the paper and to the surface of the resulting board.
  • Copper has historically demonstrated a high bactericidal power as it is an inhibitor of their growth by acting through molecular mechanisms, such as the alteration of cell membrane proteins and the provocation of oxidative stress. Therefore, it has been thought that using copper as an impregnation additive could then confer antimicrobial properties to the melamine board.
  • Patent US 8,563,020 B2 "Compositions and methods for antimicrobial metal nanoparticles” refers to the use of copper nanoparticles in various industrial applications, with the aim of conferring antimicrobial properties to the final product. However, its use as an impregnation additive in amino resins for the production of melamine boards is not mentioned, nor is the method of adding them to achieve antimicrobial properties on the board surface.
  • Patent application WO 2013/086647 A1 "Active-powder biocidal composition comprising at least one copper salt and at least one zinc salt and the method for the production thereof", mentions the use of copper and zinc salts in melamine resins for post-formed panel applications. Said patent mentions the benefits of applying copper as an antimicrobial agent, but always acting as salts. This antimicrobial capacity in amino resins is also not related to the size of the copper particles.
  • Patent US 10,105,875 B2 "Enhanced surfaces, coatings, and related methods" mentions a method of applying a liquid with wide-range particles to confer properties on the surface coating. The mentioned range includes that of nanoparticles, but no mention is made of an application as an additive in ammica resins for impregnation of paper whose final product is a melamine-coated wood board.
  • Copper solutions tend to have an intense hue, which could directly affect the color of the paper (especially white), transferring this effect to the resulting board. Therefore, it is necessary to control this effect in order not to obtain significant color differences with respect to the standard.
  • copper in solution causes changes in the reactivity of the resin, which generates variations in the time it takes to polymerize (turbidity time). These variations can be reduced by lowering the copper concentration in the resin, but the decrease in the copper concentration in the impregnation bath is opposed to achieving a concentration such that the antimicrobial effect is significant.
  • Figure 1 represents a flow diagram of the impregnation process for wood panel covering papers.
  • Figure 2 shows the values of the reduction of the bacterial load represented by %l (percentage reduction of the inoculum with respect to the initial), at 2, 6, 8 and 24 hours after applying the Cu NPs on both sides.
  • Figure 3 shows the values of the reduction of the bacterial load represented by %l (percentage reduction of the inoculum with respect to the initial), at 2, 6, 8 and 24 hours after applying the Cu NPs on the surface side.
  • Figure 4 shows the color differences in white melamine boards compared to the control group (standard without Cu NPs), when using a concentration of 10,000 ppm and 7,500 ppm, at an application of 0.003% w/w of Cu NPs. relative to the MF resin.
  • Figure 5 shows the differences in the turbidity time of the MF resin when using Cu NPs with respect to the operational standard.
  • Figure 6 shows the cloud time versus the percentage of catalyst used.
  • the present invention reveals that a solution of copper nanoparticles (Cu NPs) in an aqueous or organic medium, with a particle size in a range between 0.1 nm and 20 nm, has a high dispersion capacity in amino resins such as such as urea-formaldehyde (UF), melamine-formaldehyde (MF), melamine-urea-formaldehyde (MUF) and when used as an impregnation additive in decorative paper for melamine boards, it confers high antimicrobial properties to the resulting surface.
  • amino resins such as such as urea-formaldehyde (UF), melamine-formaldehyde (MF), melamine-urea-formaldehyde (MUF)
  • the paper impregnation process for the coating of wood boards includes the following stages: 1) Preparation stage of the solution with copper nanoparticles (Cu NPs):
  • the liquid medium (12) may comprise one or more solvents, including water, ions, polar solvents, non-polar solvents, organic solvents, inorganic solvents, oils, surfactants, dispersants, stabilizers or crosslinkers.
  • the amount of additives (22) in said mixture (23) is 0.1% - 0.4% w/w of catalyst; 0.1% - 0.5% w/w wetting agent; 0.2% - 0.8% w/w buffer; and 0.1% - 0.5% w/w of anti-blocking agent with respect to the resin.
  • a mixture 2 that will be used in a second impregnation bath (36) or later (not shown in Figure 1), which comprises a MF resin (24) and one or more additives (25) selected from catalysts , wetting agents, anti-dusting agents, mold release agents, antiblocking agents and buffers.
  • the amount of additives (25) in said mixture is 0.1% - 0.4% w/w of catalyst; 0.1% - 0.5% w/w wetting agent; 0.05% - 0.3% w/w anti-dusting agent; 0.1% - 0.6% w/w release agent; 0.1% - 0.5% w/w of antiblocking agent; and 0.2% - 0.8% w/w of buffer with respect to the resin.
  • the Cu NPs dispersion (14) is added either to mixture 1 (23), to mixture 2 (26) or to both (in figure 1 only the option of adding the Cu NPs solution (14 ) to mixture 2 (26)).
  • the amount of total resin (21, 24) in the system corresponds to 50% - 60% in relation to the total weight of the formed paper.
  • the amount of resin (24) in mixture 2 (26) is 30-50 g/m 2 (grams of resin per square meter of MF resin).
  • Catalysts promote the progress of the resin reaction in the target pressing times; wetting agents break the surface tension of liquids, helping the resin to penetrate easily into the paper, in turn reducing the viscosity of the mixture; anti-dust agents decrease the tendency for resin bubbles to form on the paper; anti-blocking agents prevent the impregnated sheets from clumping together when stored together; the release agents allow the demoulding of the sheet when it is hot pressed, thus preventing the sheets from sticking to the press plates; and the buffers or buffers that fulfill the function of neutralizing the pH changes in the resin that it may suffer.
  • Buffers or buffers generate increases in turbidity times (TT) since they directly counteract the effect of the catalyst in lowering the pH. That is, the resin becomes more "resistant” to lowering its pH due to the effect of the catalyst when it is in the presence of a buffer and consequently the TT increases.
  • the addition of buffers helps to reduce the reaction rate of the resin, so as to enable the addition of the Cu NPs (which increase the rate of the reaction).
  • the addition of buffers is not necessary. Therefore, the buffer is added to the mixture in which the Cu NPs are added.
  • Buffers can be selected from theethanolamine and borax.
  • the amount of Cu NPs (14) is in a range between 0.001% and 0.005% in dry weight of Cu NPs with respect to the resin used.
  • the impregnation time of the paper in the first impregnation bath (32) depends on the speed with which the paper passes through this bath, where the speed is in a range from 20 m/min to 90 m/min.
  • the impregnation time of the paper in the second impregnation bath (36) depends on the speed with which the paper passes through this bath, where the speed is in a range from 20 m/min to 90 m/min.
  • impregnation baths subsequent to the second bath (36), followed by subsequent drying stages may be impregnation baths subsequent to the second bath (36), followed by subsequent drying stages.
  • the speed of the process during the impregnation and drying is in a range between 20 to 90 m/min (advance of the paper in the line).
  • the resulting paper (39) from the drying stage is stored (43) in racks (44) for later use.
  • mixture 2 used in the second impregnation bath is prepared with 300 kg of MF resin, a buffer of theethanolamine or borax in a range of 0.2 to 0.8% by weight with respect to to the resin, a catalyst (chosen between Alton HM 1010, DeuroCure KS-XL, where the main component corresponds to paratoluenesulfonic acid) in a range of 10% to 40% with respect to the operational standard (2.9 kg of catalyst v/ s 13.9 kg used as standard) and the solution of Cu NPs in an amount of 0.58 kg, at a concentration of 3,750 ppm.
  • a catalyst chosen between Alton HM 1010, DeuroCure KS-XL, where the main component corresponds to paratoluenesulfonic acid
  • the operational standard 2.9 kg of catalyst v/ s 13.9 kg used as standard
  • Cu NPs in an amount of 0.58 kg, at a concentration of 3,750 ppm.
  • the resulting impregnated paper was pressed on a 15-mm-thick particleboard (PB) to which quality tests were carried out after being melamine.
  • PB 15-mm-thick particleboard
  • a solution of Cu NPs with a concentration of 7,500 ppm is prepared, where the size of the nanoparticles is between 7 and 8 nm and the liquid medium comprises a stabilizing agent.
  • a first impregnation bath which comprises a urea-formaldehyde (UF) resin and additives selected from wetting agents (such as Deurowet MA11, Alton WLF 14), catalysts (such as DeuroCure FC, Alton HM 1448) and agents.
  • wetting agents such as Deurowet MA11, Alton WLF 14
  • catalysts such as DeuroCure FC, Alton HM 1448
  • agents. anti-blocking (DeuroSlide FA) mixture 1 which confer properties to the paper to prevent its agglomeration and/or facilitate the passage of the resin to the center of the paper.
  • the amount of wetting agent is in the range of 0.1% to 0.5% w/w with respect to the UF resin; the amount of catalyst is in the range of 0.1 to 0.4% w/w with respect to the UF resin; and the amount of antiblocking agent is in the range of 0.1% to 0.5% w/w with respect to the UF resin.
  • the gel time of the resin is regulated by adjusting the amount of catalyst used, such that the value of the gel time is in a range of 2'30" to 3'.
  • a second impregnation bath which comprises a melamine-formaldehyde (MF) resin, additives selected from release agents (such as DeuroLease PHO, Alton R 1014), anti-dust agents (such as DeuroChem ADV, Alton ES 700), catalysts (such as DeuroCure KS-XL, Alton HM 1010), and the solution of Cu NPs in an amount of 7.5 g of Cu NPs per kg of liquid MF resin (mix 2).
  • release agents such as DeuroLease PHO, Alton R 1014
  • anti-dust agents such as DeuroChem ADV, Alton ES 700
  • catalysts such as DeuroCure KS-XL, Alton HM 1010
  • the amount of release agent is in the range of 0.1% to 0.6% w/w with respect to the MF resin; the amount of catalyst is in the range of 0.1 to 0.4% w/w with respect to the MF resin; and the amount of the anti-dusting agent is in the range of 0.05% to 0.3% w/w with respect to the MF resin.
  • the turbidity time of the resin is regulated by adjusting the amount of catalyst used such that the value is in a range of 6' to 6'30”.
  • a white paper with a weight of 80 g/m 2 is impregnated in the first impregnation bath, adding an amount of mixture 1 such that the final weight (gram weight) of the paper with the resin and the additives is 145 g/m 2 dry weight (paper plus resin).
  • the paper is dried by means of a dryer in stages with forced air with temperatures in the range of 100 to 220°C at a speed of 50 m/min, until reaching a humidity of 12% to 14%.
  • the resulting paper is re-impregnated in the second impregnation bath, adding an amount of mixture 2 such that the final weight (grammage) of the paper with the resin and the additives is 185 g/m 2 in dry weight (paper plus resin).
  • the paper is dried a second time by a forced air stage dryer with temperatures in the range of 100 to 220°C at a speed of 50 m/min.
  • the parameters of the oven temperature and the speed of the paper line are adjusted so that the humidity at the paper outlet is in a range of 4.5 to 5%.
  • the resulting impregnated paper is pressed onto the chipboard (PB) in a hot press at a specific pressing pressure between 20 and 50 kg/cm 2 and a temperature between 170°C and 220°C, for a time that varies between 9 and 25 seconds in order to obtain a uniform melamine surface.
  • Figure 2 shows a high antimicrobial efficiency for both the S. aureus strains and the E. coli strain, where already after 2 hours of contact a reduction of the initial inoculum of over 99.9% is achieved.
  • the percentage I (%l) corresponds to the percentage of reduction of the bacterial load with respect to the initial inoculum, where it is calculated according to the following formula: 100
  • A bacterial concentration of the control after incubation.
  • the gel time as well as the turbidity time corresponds to the time in which the resin reacts when immersed in a water bath at 100°C. It corresponds to a quality parameter, which strongly depends on the type of product (darker papers require more time and lighter paper less time). It must be considered that these values with which the plants work should not be altered, regardless of the type of components/additives that are added to the impregnation baths. This is how the addition of Cu NPs to the second impregnation bath significantly decreases the turbidity time values. To avoid these changes in the gel time and turbidity values, the amount of catalyst used in the mixtures of both should be reduced.
  • a solution of Cu NPs with a concentration of 10,000 ppm will be prepared, where the size of the nanoparticles is between 7 and 8 nm and the liquid medium comprises a stabilizing agent.
  • a first impregnation bath which comprises a urea-formaldehyde (UF) resin and additives selected from wetting agents (such as Deurowet MA11, Alton WLF 14), catalysts (such as DeuroCure FC, Alton HM 1448) and agents.
  • wetting agents such as Deurowet MA11, Alton WLF 14
  • catalysts such as DeuroCure FC, Alton HM 1448
  • agents. anti-blocking such as DeuroSlide FA) (mixture 1) which confer properties to the paper to prevent its agglomeration and/or facilitate the passage of the resin to the center of the paper.
  • the amount of wetting agent is in the range of 0.1% to 0.5% w/w with respect to the UF resin; the amount of catalyst is in the range of 0.1 to 0.4% w/w with respect to the UF resin; and the amount of anti-blocking agent is in the range of 0.1% to 0.5% w/w with respect to the UF resin.
  • the gel time is regulated the rest by adjusting the amount of catalyst used, such that the value of the gel time is in a range of 2'30” to 3'.
  • Two second impregnation baths are prepared, where one of the second impregnation baths contains the Cu NPs solution at a concentration of 10,000 ppm (only for the upper face of the paper) and the other does not (for the lower face of the paper). ).
  • These baths comprise a melamine-formaldehyde (MF) resin, additives selected from mold release agents (such as DeuroLease PHO, Alton R 1014), anti-dust agents (such as DeuroChem ADV, Alton ES 700), catalysts (such as DeuroCure KS-XL, Alton HM 1010).
  • mold release agents such as DeuroLease PHO, Alton R 1014
  • anti-dust agents such as DeuroChem ADV, Alton ES 700
  • catalysts such as DeuroCure KS-XL, Alton HM 1010
  • the amount of Cu NPs used in the second impregnation bath that contains them is 10 g of Cu NPs per kg of liquid MF resin (mix 2).
  • the amount of release agent is in the range of 0.1% to 0.6% w/w with respect to the MF resin; the amount of catalyst is in the range of 0.1 to 0.4% w/w with respect to the MF resin; and the amount of surfactant is in the range of 0.05% to 0.3% w/w with respect to the MF resin.
  • the turbidity time of the resin is regulated by adjusting the amount of catalyst used so that the value is in a range of 6' to 6'30".
  • a white paper with a weight of 80 g/m 2 is impregnated in the first impregnation bath, adding an amount of mixture 1 such that the final weight (gram weight) of the paper with the resin and the additives is 145 g/m 2 dry weight (paper plus resin).
  • the paper is dried by means of a dryer in stages with forced air with temperatures in the range of 100 to 220°C at a speed of 50 m/min, until reaching a humidity of 12% to 14%. • The resulting paper is impregnated again in the second impregnation baths, where the upper face is impregnated in the second impregnation bath that contains the Cu NPs and the lower face is impregnated in the second impregnation bath that does not contain them. contains. A total amount (of resin + additives) is added such that the final weight (grammage) of the paper with the resin and the additives is 185 g/m 2 in dry weight (paper plus resin).
  • the paper is dried a second time by a forced air stage dryer with temperatures in the range of 100 to 220°C at a speed of 50 m/min.
  • the parameters of the oven temperature and the speed of the paper line are adjusted so that the humidity at the paper outlet is in a range of 4.5 to 5%.
  • the resulting impregnated paper is pressed onto the chipboard (PB) in a hot press at a specific pressing pressure between 20 and 50 kg/cm2 and a temperature between 170°C and 220°C, for a time that varies between 9 and 25 seconds in order to obtain a uniform melamine surface.
  • PB chipboard
  • Test A application of Cu NPs on the upper face of the paper: 30 samples of approximately 12 mm height
  • Test B application of Cu NPs on both sides of the paper: 30 samples approximately 12 mm high
  • the inoculated volume in each of the samples was 400 pl and a McFarland 0.5 Standard was used to obtain a concentration of 1.0x10 6 CFU/ml in each of the strains used.
  • the bacteria were recovered using sterile tweezers to add the film to a tube with 10 ml of SCDLP medium and then the sample was collected using pieces of KIMTECH WS cloth (50% Rayon/50% Polyester) sterilized in pupinel.
  • Table 1 shows the average count of E. coli and S. aureusen (CFU/cm 2 ) and the base 10 logarithm of the analyzed samples.
  • Table 1 shows the antibacterial activity of the samples evaluated after 2 and 24 hours of incubation for the 2 strains used and the percentage of count reduction in CFU/cm 2 comparing each of the samples with and without treatment.
  • Figure 4 shows that there are no significant color differences (AE ⁇ 1.0) when using copper NPs in impregnated white paper if used in the stipulated range.
  • Figure 6 corresponds to an example where the variations in the turbidity time (TT) were observed when changing the amount of catalyst (0%, 0.1%, 0.2% and 0.3%) and buffer (theethanolamine (TEA), 0.2%, 0.35%, 0.5%) in the MF resin. It is determined that the optimal condition in this case (TT range between 4'30” and 4'50”, between the lower limit (LCI) and the upper limit (LCS)) would be using an addition of 0.35% w/w triethanolamine and 0.25% w/w catalyst relative to MF resin.
  • TT turbidity time
  • the present invention achieves the production of a melamine board with antimicrobial properties conferred by the copper present in the form of NPs.
  • the addition of these NPs in solution as an impregnation additive allows a high antimicrobial efficiency at low concentrations, which allows the process to operate normally without significant modifications.
  • Through the present invention it is possible to obtain melamine boards as difficult as black and graphite, without presenting quality problems. Furthermore, in espresso boards no bright spots are observed with the use of Cu NPs.

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  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Pest Control & Pesticides (AREA)
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  • Plant Pathology (AREA)
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Abstract

Disclosed is a paper impregnation method for covering wooden boards, with antimicrobial effect, which does not interfere with the final colour of the paper. The method comprises the steps of: preparing a copper nanoparticle dispersion, to be included in a mixture used in at least one impregnation bath, the bath also comprising resins and additives; Impregnating the paper in two or more impregnation baths, separated by steps of drying, wherein the nanoparticles can be impregnated on both sides of the paper or on only one side; and lastly, pressing the paper onto the wooden board and subsequently cutting to the size of the board.

Description

PROCESO DE IMPREGNACION DE PAPEL PARA RECUBRIR TABLEROS DE MADERA CON EFECTO ANTIMICROBIANO PAPER IMPREGNATION PROCESS TO COVER WOODEN BOARDS WITH ANTIMICROBIAL EFFECT
Campo de la Invención: Field of the Invention:
La presente invención se relaciona con la aplicación de compuestos antimicrobianos que comprenden nanopartículas de cobre (NPs de Cu), siendo éstas adicionadas al proceso de impregnación de papeles con resinas amínicas (urea-formaldehído (UF), melamina- formaldehído (MF), melamina-urea-formaldehído (MUF)), para el recubrimiento de tableros de madera. The present invention is related to the application of antimicrobial compounds that comprise copper nanoparticles (Cu NPs), these being added to the paper impregnation process with amino resins (urea-formaldehyde (UF), melamine-formaldehyde (MF), melamine -urea-formaldehyde (MUF)), for the coating of wooden boards.
El producto resultante comprende un tablero a base de madera recubierto con melamina que posee una alta efectividad antimicrobiana. The resulting product comprises a melamine-coated wood-based board that has high antimicrobial effectiveness.
Estado del Arte: State of the Art:
En los canales tradicionales de impregnación para la producción de tableros melaminizados, el papel se impregna con resinas ureicas y melamínicas, utilizando un proceso de polimerización parcial. Los rollos de papel se cargan en la máquina desbobinadora y se alimentan a través de una serie de rodillos en uno o más baños de impregnación, en donde se tiene una mezcla de resinas además de otros aditivos de impregnación. La mezcla anterior de resina y aditivos de impregnación se empapa en el papel, el cual posteriormente debe ser secado en hornos a una temperatura cuidadosamente controlada en función de la velocidad. Después de pasar por el horno, el producto terminado (papel impregnado seco) se corta automáticamente al tamaño requerido (láminas de papel impregnado seco) para el proceso de melaminizado de los tableros de madera. Finalmente, las láminas apiladas son almacenadas en racks, en donde con la ayuda del agente anti-blocking (parte del resto de los aditivos de impregnación) se evita que las láminas se peguen entre sí. In the traditional impregnation channels for the production of melaminized boards, the paper is impregnated with urea and melamine resins, using a partial polymerization process. The paper rolls are loaded into the unwinding machine and fed through a series of rollers into one or more impregnation baths, where there is a mixture of resins in addition to other impregnation additives. The previous mixture of resin and impregnation additives is soaked in the paper, which must then be dried in ovens at a carefully controlled temperature depending on the speed. After going through the oven, the finished product (dry impregnated paper) is automatically cut to the required size (dry impregnated paper sheets) for the wood board melamine process. Finally, the stacked sheets are stored in racks, where with the help of the anti-blocking agent (part of the rest of the impregnation additives) the sheets are prevented from sticking together.
Los aditivos de impregnación se refieren a compuestos químicos, tales como antipolvo, humectantes, anti-blocking, desmoldantes, etc., que i se incorporan al proceso de aplicación de resinas am micas en dichos papeles, los cuales confieren propiedades tanto al papel como a la superficie del tablero resultante. Impregnation additives refer to chemical compounds, such as anti-dust, humectants, anti-blocking, release agents, etc., that i they are incorporated into the process of applying ammica resins in said papers, which confer properties both to the paper and to the surface of the resulting board.
El cobre ha demostrado históricamente un alto poder bactericida al ser un inhibidor del crecimiento de éstas al actuar mediante mecanismos moleculares, tales como la alteración de proteínas de la membrana celular y de la provocación de estrés oxidativo. Por lo que se ha pensado que al utilizar cobre como un aditivo de impregnación se le podrían entonces conferir propiedades antimicrobianas al tablero melaminizado. Copper has historically demonstrated a high bactericidal power as it is an inhibitor of their growth by acting through molecular mechanisms, such as the alteration of cell membrane proteins and the provocation of oxidative stress. Therefore, it has been thought that using copper as an impregnation additive could then confer antimicrobial properties to the melamine board.
La patente US 8.563.020 B2: “Compositions and methods for antimicrobial metal nanoparticles” hace referencia al uso de nanopartículas de cobre en diversas aplicaciones industriales, con el objetivo de conferir propiedades antimicrobianas al producto final. Sin embargo, no se menciona su utilización como un aditivo de impregnación en resinas amínicas para producción de tableros melaminizados, ni al método de adición con éstas para conseguir las propiedades antimicrobianas en la superficie del tablero. Patent US 8,563,020 B2: "Compositions and methods for antimicrobial metal nanoparticles" refers to the use of copper nanoparticles in various industrial applications, with the aim of conferring antimicrobial properties to the final product. However, its use as an impregnation additive in amino resins for the production of melamine boards is not mentioned, nor is the method of adding them to achieve antimicrobial properties on the board surface.
La solicitud de patente WO 2013/086647 A1 : “Active-powder biocidal composition comprising at least one copper salt and at least one zinc salt and the method for the production thereof’, menciona el uso de sales de cobre y zinc en resinas melamínicas para aplicaciones en paneles post-form ados. Dicha patente menciona los beneficios de la aplicación de cobre como agente antimicrobiano, pero siempre actuando como sales. Esta capacidad antimicrobiana en resinas amínicas tampoco es relacionada con el tamaño de partículas del cobre. Patent application WO 2013/086647 A1: "Active-powder biocidal composition comprising at least one copper salt and at least one zinc salt and the method for the production thereof", mentions the use of copper and zinc salts in melamine resins for post-formed panel applications. Said patent mentions the benefits of applying copper as an antimicrobial agent, but always acting as salts. This antimicrobial capacity in amino resins is also not related to the size of the copper particles.
La patente US 10.105.875 B2: “Enhanced surfaces, coatings, and related methods” menciona un método de aplicación de un líquido con partículas de amplio rango para conferir propiedades en el recubrimiento de superficies. El rango mencionado incluye el de las nanopartículas, pero no se hace mención de una aplicación como aditivo en resinas am micas para impregnación de papeles cuyo producto final sea un tablero de madera melaminizado. Patent US 10,105,875 B2: "Enhanced surfaces, coatings, and related methods" mentions a method of applying a liquid with wide-range particles to confer properties on the surface coating. The mentioned range includes that of nanoparticles, but no mention is made of an application as an additive in ammica resins for impregnation of paper whose final product is a melamine-coated wood board.
Existen problemas al tratar de aplicar al cobre como parte de los aditivos de impregnación para papeles que posteriormente serán utilizados en el recubrimiento de tableros de madera. There are problems when trying to apply copper as part of the impregnating additives for papers that will later be used in the coating of wood boards.
Las soluciones de cobre tienden a presentar una tonalidad intensa, la cual podría afectar directamente el color del papel (especialmente el color blanco) traspasando dicho efecto al tablero resultante. Por lo que es necesario el control de este efecto para no obtener diferencias de color significativas respecto al estándar. Copper solutions tend to have an intense hue, which could directly affect the color of the paper (especially white), transferring this effect to the resulting board. Therefore, it is necessary to control this effect in order not to obtain significant color differences with respect to the standard.
Por otra parte, el cobre en solución provoca cambios en la reactividad de la resina lo que genera variaciones en el tiempo que demora ésta en polimehzar (tiempo de turbidez). Dichas variaciones pueden disminuirse bajando la concentración de cobre en la resina, pero la disminución de la concentración de cobre en el baño de impregnación se contrapone con el propósito de conseguir una concentración tal que el efecto antimicrobiano sea significativo. On the other hand, copper in solution causes changes in the reactivity of the resin, which generates variations in the time it takes to polymerize (turbidity time). These variations can be reduced by lowering the copper concentration in the resin, but the decrease in the copper concentration in the impregnation bath is opposed to achieving a concentration such that the antimicrobial effect is significant.
Por lo tanto, es necesario encontrar un proceso de impregnación de papel que incluya al cobre como parte de los aditivos de impregnación, que evite la interferencia con el color final del papel y siga manteniendo su efecto antimicrobiano en el papel que recubrirá posteriormente a los tableros de madera. Therefore, it is necessary to find a paper impregnation process that includes copper as part of the impregnation additives, which avoids interference with the final color of the paper and continues to maintain its antimicrobial effect on the paper that will later cover the boards. of wood.
Descripción de las figuras: Description of the figures:
La figura 1 representa un diagrama de flujo del proceso de impregnación para papeles de recubrimiento de paneles de madera. La figura 2 muestra los valores de la reducción de la carga bacteriana representado por %l (porcentaje de reducción del inoculo respecto al inicial), a las 2, 6, 8 y 24 horas después de aplicar las NPs de Cu por ambas caras. Figure 1 represents a flow diagram of the impregnation process for wood panel covering papers. Figure 2 shows the values of the reduction of the bacterial load represented by %l (percentage reduction of the inoculum with respect to the initial), at 2, 6, 8 and 24 hours after applying the Cu NPs on both sides.
La figura 3 muestra los valores de la reducción de la carga bacteriana representado por %l (porcentaje de reducción del inoculo respecto al inicial), a las 2, 6, 8 y 24 horas luego de aplicar las NPs de Cu por la cara superficial. Figure 3 shows the values of the reduction of the bacterial load represented by %l (percentage reduction of the inoculum with respect to the initial), at 2, 6, 8 and 24 hours after applying the Cu NPs on the surface side.
La figura 4 muestra las diferencias de color en tableros melaminizados con color blanco respecto al grupo control (estándar sin NPs de Cu), al utilizar una concentración de 10.000 ppm y 7.500 ppm, a una aplicación de 0,003% p/p de NPs de Cu respecto a la resina MF. Figure 4 shows the color differences in white melamine boards compared to the control group (standard without Cu NPs), when using a concentration of 10,000 ppm and 7,500 ppm, at an application of 0.003% w/w of Cu NPs. relative to the MF resin.
La figura 5 muestra las diferencias en el tiempo de turbidez de la resina MF al utilizar NPs de Cu respecto al estándar operacional. Figure 5 shows the differences in the turbidity time of the MF resin when using Cu NPs with respect to the operational standard.
La figura 6 muestra el tiempo de turbidez versus el porcentaje de catalizador utilizado. Figure 6 shows the cloud time versus the percentage of catalyst used.
Descripción detallada de la invención: Detailed description of the invention:
La presente invención revela que una solución de nanopartículas de cobre (NPs de Cu) en un medio acuoso u orgánico, con un tamaño de partículas en un rango entre 0,1 nm y 20 nm, posee una alta capacidad de dispersión en resinas amínicas tales como urea-formaldehído (UF), melamina-formaldehído (MF), melamina-urea-formaldehído (MUF) y que al utilizarse como aditivo de impregnación en papeles decorativos para tableros melaminizados le confiere propiedades a la superficie resultante de alto poder antimicrobiano. The present invention reveals that a solution of copper nanoparticles (Cu NPs) in an aqueous or organic medium, with a particle size in a range between 0.1 nm and 20 nm, has a high dispersion capacity in amino resins such as such as urea-formaldehyde (UF), melamine-formaldehyde (MF), melamine-urea-formaldehyde (MUF) and when used as an impregnation additive in decorative paper for melamine boards, it confers high antimicrobial properties to the resulting surface.
El proceso de impregnación de papel para el recubrimiento de tableros de madera comprende las siguientes etapas: 1) Etapa de preparación de la solución con nanoparticulas de cobre (NPs de Cu): The paper impregnation process for the coating of wood boards includes the following stages: 1) Preparation stage of the solution with copper nanoparticles (Cu NPs):
Preparar (13) una dispersión (14) de NPs de Cu (11 ) con un tamaño de partículas entre 0,1 nm y 20 nm en un medio líquido (12). En donde las NPs de Cu (11 ) tienen un nivel de pureza mayor a 95% en una concentración de 1.000 a 10.000 ppm. Prepare (13) a dispersion (14) of Cu NPs (11) with a particle size between 0.1 nm and 20 nm in a liquid medium (12). Where the NPs of Cu (11) have a purity level greater than 95% in a concentration of 1,000 to 10,000 ppm.
El medio líquido (12) puede comprender uno o vahos solventes, incluyendo agua, iones, solventes polares, solventes no-polares, solventes orgánicos, solventes inorgánicos, aceites, surfactantes, dispersantes, estabilizantes o entrecruzantes. The liquid medium (12) may comprise one or more solvents, including water, ions, polar solvents, non-polar solvents, organic solvents, inorganic solvents, oils, surfactants, dispersants, stabilizers or crosslinkers.
2) Etapa de mezclado de la resina con los aditivos: 2) Stage of mixing the resin with the additives:
Preparar una mezcla 1 (23) que será utilizada en un primer baño de impregnación (32), la cual comprende una o más resinas (21 ) seleccionada de: UF, MF, MUF o una mezcla de las mismas y uno o más aditivos (22) seleccionados de: catalizadores, agentes humectantes, tampones o búfers y agentes anti-blocking. Prepare a mixture 1 (23) that will be used in a first impregnation bath (32), which comprises one or more resins (21) selected from: UF, MF, MUF or a mixture thereof and one or more additives ( 22) selected from: catalysts, wetting agents, buffers and anti-blocking agents.
La cantidad de aditivos (22) en dicha mezcla (23) es de 0, 1 % - 0,4% p/p de catalizador; 0,1 % - 0,5% p/p de agente humectante; 0,2% - 0,8% p/p de búfer; y 0,1 % - 0,5% p/p de agente anti-blocking con respecto a la resina. The amount of additives (22) in said mixture (23) is 0.1% - 0.4% w/w of catalyst; 0.1% - 0.5% w/w wetting agent; 0.2% - 0.8% w/w buffer; and 0.1% - 0.5% w/w of anti-blocking agent with respect to the resin.
Preparar una mezcla 2 (26) que será utilizada en un segundo baño de impregnación (36) o posteriores (no mostrado en la figura 1 ), la cual comprende una resina (24) MF y uno o más aditivos (25) seleccionados de catalizadores, agentes humectantes, agentes antipolvo, agentes desmoldantes, agentes antiblocking y tampones o búfers. Prepare a mixture 2 (26) that will be used in a second impregnation bath (36) or later (not shown in Figure 1), which comprises a MF resin (24) and one or more additives (25) selected from catalysts , wetting agents, anti-dusting agents, mold release agents, antiblocking agents and buffers.
La cantidad de aditivos (25) en dicha mezcla es de 0,1 % - 0,4% p/p de catalizador; 0,1 % - 0,5% p/p de agente humectante; 0,05% - 0,3% p/p de agente antipolvo; 0,1 % - 0,6% p/p de agente desmoldante; 0,1 % - 0,5% p/p de agente antiblocking; y 0,2% - 0,8% p/p de bufer con respecto a la resina. The amount of additives (25) in said mixture is 0.1% - 0.4% w/w of catalyst; 0.1% - 0.5% w/w wetting agent; 0.05% - 0.3% w/w anti-dusting agent; 0.1% - 0.6% w/w release agent; 0.1% - 0.5% w/w of antiblocking agent; and 0.2% - 0.8% w/w of buffer with respect to the resin.
La dispersión de NPs de Cu (14) se agrega ya sea a la mezcla 1 (23), a la mezcla 2 (26) o a ambas (en la figura 1 sólo se muestra la opción de agregar la solución de NPs de Cu (14) a la mezcla 2 (26)). The Cu NPs dispersion (14) is added either to mixture 1 (23), to mixture 2 (26) or to both (in figure 1 only the option of adding the Cu NPs solution (14 ) to mixture 2 (26)).
La cantidad de resina total (21 , 24) en el sistema corresponde a un 50% - 60% en relación al peso total del papel formado. Por su parte la cantidad de resina (24) en la mezcla 2 (26) es de 30 - 50 g/m2 (gramos de resina por metro cuadrado de resina MF). The amount of total resin (21, 24) in the system corresponds to 50% - 60% in relation to the total weight of the formed paper. For its part, the amount of resin (24) in mixture 2 (26) is 30-50 g/m 2 (grams of resin per square meter of MF resin).
Los catalizadores promueven el avance de la reacción de la resina en los tiempos de prensado objetivo; los agentes humectantes rompen la tensión superficial de los líquidos ayudando a que la resina penetre de manera fácil en el papel, disminuyendo a su vez la viscosidad de la mezcla; los agentes antipolvo disminuyen la tendencia de la formación de burbujas de resina en el papel; los agentes anti-blocking permiten que las hoja impregnadas no se aglutinen unas con otras al estar almacenadas juntas; los desmoldantes permiten el desmolde de la lámina al prensarse en caliente, evitando así que las láminas se peguen a los platos de la prensa; y los tampones o búfers que cumple la función de neutralizar los cambios de pH en la resina que ésta pueda sufrir. Catalysts promote the progress of the resin reaction in the target pressing times; wetting agents break the surface tension of liquids, helping the resin to penetrate easily into the paper, in turn reducing the viscosity of the mixture; anti-dust agents decrease the tendency for resin bubbles to form on the paper; anti-blocking agents prevent the impregnated sheets from clumping together when stored together; the release agents allow the demoulding of the sheet when it is hot pressed, thus preventing the sheets from sticking to the press plates; and the buffers or buffers that fulfill the function of neutralizing the pH changes in the resin that it may suffer.
Los búfers o tampones generan aumentos en los tiempos de turbidez (TT) ya que contrarrestan directamente el efecto del catalizador de disminuir el pH. Es decir, la resina se vuelve más “resistente” a disminuir su pH por efecto del catalizador cuando está en presencia de un búfer y en consecuencia el TT aumenta. Buffers or buffers generate increases in turbidity times (TT) since they directly counteract the effect of the catalyst in lowering the pH. That is, the resin becomes more "resistant" to lowering its pH due to the effect of the catalyst when it is in the presence of a buffer and consequently the TT increases.
En aquellas plantas en donde los tiempos de reacción de la resina, es decir los TT son medio/altos, la adición de búfers ayuda a disminuir la velocidad de reacción de la resina, de modo de posibilitar la adición de las NPs de Cu (las cuales aumentan la velocidad de la reacción). En tanto para plantas en donde los TT son bajos no es necesaria la adición de búfers. Por lo tanto, el búfer es agregado a la mezcla en la cual se adicionen las NPs de Cu. In those plants where the reaction times of the resin, that is, the TT are medium/high, the addition of buffers helps to reduce the reaction rate of the resin, so as to enable the addition of the Cu NPs (which increase the rate of the reaction). As for plants where the TT are low, the addition of buffers is not necessary. Therefore, the buffer is added to the mixture in which the Cu NPs are added.
Los búfers se pueden seleccionar de thetanolamina y bórax. Buffers can be selected from theethanolamine and borax.
La cantidad de NPs de Cu (14) se encuentra en un rango entre 0,001 % y 0,005% en peso seco de NPs de Cu respecto a la resina utilizada. The amount of Cu NPs (14) is in a range between 0.001% and 0.005% in dry weight of Cu NPs with respect to the resin used.
3) Etapa de impregnación del papel: 3) Paper impregnation stage:
Impregnar un papel (31 ) con un gramaje entre 35 a 120 g/m2, en un primer baño de impregnación (32) que comprende la mezcla 1 (23), alcanzando una carga de resina (peso seco más papel) entre 100 a 220 g/m2. El tiempo de impregnación del papel en el primer baño de impregnación (32) depende de la velocidad con la cual pasa el papel a través de este baño, donde la velocidad se encuentra en un rango de 20 m/min a 90 m/min. Impregnate a paper (31) with a grammage between 35 and 120 g/m 2 , in a first impregnation bath (32) that includes mixture 1 (23), reaching a resin load (dry weight plus paper) between 100 and 220g / m2. The impregnation time of the paper in the first impregnation bath (32) depends on the speed with which the paper passes through this bath, where the speed is in a range from 20 m/min to 90 m/min.
Secar el papel impregnado (33) en el primer baño de impregnación (32) en una etapa de secado (34) con aire forzado en un secador por etapas a temperaturas que fluctúan en un rango entre 100 a 220°C, hasta alcanzar una humedad de al menos 12%. Dry the impregnated paper (33) in the first impregnation bath (32) in a drying stage (34) with forced air in a staged dryer at temperatures ranging from 100 to 220°C, until reaching a humidity of at least 12%.
Impregnar el papel secado (35) en un segundo baño de impregnación (36) que comprende la mezcla 2 (26), alcanzando una carga final de resina (peso seco más papel) entre 120 a 260 g/m2. El tiempo de impregnación del papel en el segundo baño de impregnación (36) depende de la velocidad con la cual pasa el papel a través de este baño, donde la velocidad se encuentra en un rango de 20 m/min a 90 m/min. Impregnate the dried paper (35) in a second impregnation bath (36) comprising mixture 2 (26), reaching a final resin load (dry weight plus paper) between 120 and 260 g/m 2 . The impregnation time of the paper in the second impregnation bath (36) depends on the speed with which the paper passes through this bath, where the speed is in a range from 20 m/min to 90 m/min.
Secar el papel impregnado (37) en el segundo baño de impregnación (36) en una última etapa de secado (38) con aire forzado en un secador por etapas a temperaturas que fluctúan en un rango entre 100 a 220°C, hasta alcanzar una humedad inferior a 6%. Dry the impregnated paper (37) in the second impregnation bath (36) in a final drying stage (38) with forced air in a dryer by stages at temperatures that fluctuate in a range between 100 to 220°C, until reaching a humidity of less than 6%.
Opcionalmente pueden existir baños de impregnación posteriores al segundo baño (36), seguido de etapas de secado posteriores. Optionally, there may be impregnation baths subsequent to the second bath (36), followed by subsequent drying stages.
Obtener un papel impregnado con NPs de Cu (39) con una humedad en un rango entre 4 a 6%. Obtain a paper impregnated with Cu NPs (39) with a humidity in a range between 4 to 6%.
La velocidad del proceso durante la impregnación y secado está en un rango de entre 20 a 90 m/min (avance del papel en la línea). The speed of the process during the impregnation and drying is in a range between 20 to 90 m/min (advance of the paper in the line).
4) Etapa de prensado, corte y almacenamiento: 4) Pressing, cutting and storage stage:
Prensar (41 ) el papel resultante (39) de la etapa de secado, sobre un sustrato, generalmente un tablero en base a madera, la presión especifica de prensado varía entre 20 y 50 kg/cm2, la temperatura se encuentra entre 170°C y 220°C y el tiempo de prensado varía entre 9 y 25 segundos. Press (41) the resulting paper (39) from the drying stage, on a substrate, generally a wood-based board, the specific pressing pressure varies between 20 and 50 kg/cm 2 , the temperature is between 170 ° C and 220°C and the pressing time varies between 9 and 25 seconds.
Cortar (42) el papel del tamaño del tablero de madera. Cut (42) the paper to the size of the wooden board.
Opcionalmente el papel resultante (39) de la etapa de secado, es almacenado (43) en racks (44) para su posterior uso. Optionally, the resulting paper (39) from the drying stage is stored (43) in racks (44) for later use.
En una de las modalidades de la invención, se prepara la mezcla 2 utilizada en el segundo baño de impregnación, con 300 kg de resina MF, un búfer de thetanolamina o bórax en un rango de 0,2 a 0,8% en peso respecto a la resina, un catalizador (elegido entre Alton HM 1010, DeuroCure KS-XL, en donde el componente principal corresponde al ácido paratoluensulfónico) en un rango de 10% a 40% respecto al estándar operacional (2,9 kg de catalizador v/s 13,9 kg utilizado de forma estándar) y la solución de NPs de Cu en una cantidad de 0,58 kg, a una concentración de 3.750 ppm. Eiemplos: In one of the embodiments of the invention, mixture 2 used in the second impregnation bath is prepared with 300 kg of MF resin, a buffer of theethanolamine or borax in a range of 0.2 to 0.8% by weight with respect to to the resin, a catalyst (chosen between Alton HM 1010, DeuroCure KS-XL, where the main component corresponds to paratoluenesulfonic acid) in a range of 10% to 40% with respect to the operational standard (2.9 kg of catalyst v/ s 13.9 kg used as standard) and the solution of Cu NPs in an amount of 0.58 kg, at a concentration of 3,750 ppm. Examples:
Los ejemplos de aplicación se llevan a cabo con la adición de NPs de Cu y una resina de melamina-formaldehído a la mezcla 2 utilizada en el segundo baño de impregnación. The application examples are carried out with the addition of Cu NPs and a melamine-formaldehyde resin to mixture 2 used in the second impregnation bath.
El papel impregnado resultante fue prensado sobre un tablero aglomerado (particleboard, o PB por sus siglas en inglés) de 15 mm de espesor al cual se le realizaron los ensayos de calidad del mismo, luego de ser melaminizado. The resulting impregnated paper was pressed on a 15-mm-thick particleboard (PB) to which quality tests were carried out after being melamine.
Ejemplo 1: Example 1:
• Se prepara una solución de NPs de Cu con una concentración de 7.500 ppm, donde el tamaño de las nanopartículas está entre 7 y 8 nm y el medio líquido comprende un agente estabilizante. • A solution of Cu NPs with a concentration of 7,500 ppm is prepared, where the size of the nanoparticles is between 7 and 8 nm and the liquid medium comprises a stabilizing agent.
• Se prepara un primer baño de impregnación el cual comprende una resina de urea-formaldehído (UF) y aditivos seleccionados de agentes humectantes (tales como Deurowet MA11 , Alton WLF 14), catalizadores (tales como DeuroCure FC, Alton HM 1448) y agentes anti-blocking (DeuroSlide FA) (mezcla 1 ) los cuales confieren propiedades al papel para evitar su aglomeración y/o facilitar el paso de la resina al centro del papel. La cantidad de agente humectante se encuentra en el rango de 0, 1 % a 0,5% p/p con respecto a la resina UF; la cantidad de catalizador se encuentra en el rango de 0,1 a 0,4% p/p con respecto a la resina UF; y la cantidad de agente antiblocking se encuentra en el rango de 0,1 % a 0,5% p/p con respecto a la resina UF. Se regula el tiempo gel de la resina ajustando la cantidad de catalizador utilizado, tal que el valor del tiempo gel se encuentre en un rango de 2’30” a 3’. • A first impregnation bath is prepared which comprises a urea-formaldehyde (UF) resin and additives selected from wetting agents (such as Deurowet MA11, Alton WLF 14), catalysts (such as DeuroCure FC, Alton HM 1448) and agents. anti-blocking (DeuroSlide FA) (mixture 1) which confer properties to the paper to prevent its agglomeration and/or facilitate the passage of the resin to the center of the paper. The amount of wetting agent is in the range of 0.1% to 0.5% w/w with respect to the UF resin; the amount of catalyst is in the range of 0.1 to 0.4% w/w with respect to the UF resin; and the amount of antiblocking agent is in the range of 0.1% to 0.5% w/w with respect to the UF resin. The gel time of the resin is regulated by adjusting the amount of catalyst used, such that the value of the gel time is in a range of 2'30" to 3'.
• Se prepara un segundo baño de impregnación el cual comprende una resina melamina-formaldehído (MF), aditivos seleccionados de agentes desmoldantes (tales como DeuroLease PHO, Alton R 1014), agentes antipolvo (tales como DeuroChem ADV, Alton ES 700), catalizadores (tales como DeuroCure KS-XL, Alton HM 1010), y la solución de NPs de Cu en una cantidad de 7,5 g de NPs de Cu por kg de resina MF líquida (mezcla 2). La cantidad de agente desmoldante se encuentra en el rango de 0,1 % a 0,6% p/p con respecto a la resina MF; la cantidad de catalizador se encuentra en el rango de 0,1 a 0,4% p/p con respecto a la resina MF; y la cantidad de agente antipolvo se encuentra en el rango de 0,05% a 0,3% p/p con respecto a la resina MF. Se regula el tiempo de turbidez de la resina ajustando la cantidad de catalizador utilizado tal que el valor se encuentre en un rango de 6’ a 6’30”. • A second impregnation bath is prepared which comprises a melamine-formaldehyde (MF) resin, additives selected from release agents (such as DeuroLease PHO, Alton R 1014), anti-dust agents (such as DeuroChem ADV, Alton ES 700), catalysts (such as DeuroCure KS-XL, Alton HM 1010), and the solution of Cu NPs in an amount of 7.5 g of Cu NPs per kg of liquid MF resin (mix 2). The amount of release agent is in the range of 0.1% to 0.6% w/w with respect to the MF resin; the amount of catalyst is in the range of 0.1 to 0.4% w/w with respect to the MF resin; and the amount of the anti-dusting agent is in the range of 0.05% to 0.3% w/w with respect to the MF resin. The turbidity time of the resin is regulated by adjusting the amount of catalyst used such that the value is in a range of 6' to 6'30”.
• Se impregna un papel blanco de gramaje 80 g/m2 en el primer baño de impregnación, agregando una cantidad de la mezcla 1 tal que el peso (gramaje) final del papel con la resina y los aditivos sea de 145 g/m2 en peso seco (papel más resina). • A white paper with a weight of 80 g/m 2 is impregnated in the first impregnation bath, adding an amount of mixture 1 such that the final weight (gram weight) of the paper with the resin and the additives is 145 g/m 2 dry weight (paper plus resin).
• Se seca el papel mediante un secador por etapas con aire forzado con temperaturas en el rango de 100 a 220°C a una velocidad de 50 m/min, hasta alcanzar una humedad de 12% a 14%. • The paper is dried by means of a dryer in stages with forced air with temperatures in the range of 100 to 220°C at a speed of 50 m/min, until reaching a humidity of 12% to 14%.
• Se vuelve a impregnar el papel resultante en el segundo baño de impregnación agregando una cantidad de la mezcla 2 tal que el peso (gramaje) final del papel con la resina y los aditivos sea de 185 g/m2 en peso seco (papel más resina). • The resulting paper is re-impregnated in the second impregnation bath, adding an amount of mixture 2 such that the final weight (grammage) of the paper with the resin and the additives is 185 g/m 2 in dry weight (paper plus resin).
• Se seca el papel por segunda vez mediante un secador por etapas con aire forzado con temperaturas en el rango de 100 a 220°C a una velocidad de 50 m/min. Los parámetros de la temperatura del homo y la velocidad de la línea de papel son ajustados tal que la humedad a la salida del papel esté en un rango de 4,5 a 5%. • Se prensa el papel impregnado resultante sobre el tablero aglomerado (PB) en una prensa caliente a una presión específica de prensado entre 20 y 50 kg/cm2 y una temperatura entre 170°C y 220°C, durante un tiempo que varía entre 9 y 25 segundos con el propósito de obtener una superficie melaminizada uniforme. • The paper is dried a second time by a forced air stage dryer with temperatures in the range of 100 to 220°C at a speed of 50 m/min. The parameters of the oven temperature and the speed of the paper line are adjusted so that the humidity at the paper outlet is in a range of 4.5 to 5%. • The resulting impregnated paper is pressed onto the chipboard (PB) in a hot press at a specific pressing pressure between 20 and 50 kg/cm 2 and a temperature between 170°C and 220°C, for a time that varies between 9 and 25 seconds in order to obtain a uniform melamine surface.
• Una vez finalizado el tablero melaminizado, se evalúa su calidad según análisis en laboratorio incluyendo capacidad antimicrobiana en S. aureus y E. coli, test de ácido, grafito, dureza superficial, diferencias en el color y resistencia a la abrasión. • Once the melamine board is finished, its quality is evaluated according to laboratory analysis including antimicrobial capacity in S. aureus and E. coli, acid test, graphite, surface hardness, differences in color and resistance to abrasion.
En la figura 2 se puede observar una alta eficiencia antimicrobiana tanto para las cepas S. aureus como para la cepa E. coli, en donde ya a las 2 horas de contacto se logra una reducción del inoculo inicial sobre el 99,9%. Figure 2 shows a high antimicrobial efficiency for both the S. aureus strains and the E. coli strain, where already after 2 hours of contact a reduction of the initial inoculum of over 99.9% is achieved.
El porcentaje I (%l) corresponde al porcentaje de reducción de la carga bacteriana respecto al inoculo inicial, en donde éste se calcula de acuerdo a la siguiente fórmula: 100
Figure imgf000012_0001
The percentage I (%l) corresponds to the percentage of reduction of the bacterial load with respect to the initial inoculum, where it is calculated according to the following formula: 100
Figure imgf000012_0001
Donde: Where:
C: concentración bacteriana del inoculo inicial. C: bacterial concentration of the initial inoculum.
A: concentración bacteriana del control después de la incubación. A: bacterial concentration of the control after incubation.
B: concentración bacteriana de las muestras de la invención después de la incubación. B: bacterial concentration of the samples of the invention after incubation.
El tiempo gel al igual que el tiempo de turbidez (para la resina MF) corresponde al tiempo en que la resina reacciona al sumergirse en un baño maria a 100°C. Corresponde a un parámetro de calidad, el cual depende fuertemente del tipo de producto (papeles más oscuros requieren mayor tiempo y papeles mas claros menos tiempo). Hay que considerar que no se deben alterar estos valores con los que trabajan las plantas, independientemente del tipo de componentes/aditivos que se agreguen a los baños de impregnación. Es así como la adición de NPs de Cu al segundo baño de impregnación disminuye significativamente los valores de tiempo de turbidez, para evitar estas alteraciones en los valores de tiempo de gel y de turbidez se debe reducir la cantidad de catalizador utilizado en las mezclas de ambos baños de impregnación y adicionalmente se puede considerar el uso de un búfer en la resina. En los casos en que los tiempos de turbidez son bajos (del orden de 4’ a 4’30”), no se requiere adición de ningún tipo de búfer y sólo con la reducción de la cantidad de catalizador se logra el objetivo de mantener los valores de tiempo de gel y/o turbidez dentro de los rangos normales de operación de las plantas. The gel time as well as the turbidity time (for the MF resin) corresponds to the time in which the resin reacts when immersed in a water bath at 100°C. It corresponds to a quality parameter, which strongly depends on the type of product (darker papers require more time and lighter paper less time). It must be considered that these values with which the plants work should not be altered, regardless of the type of components/additives that are added to the impregnation baths. This is how the addition of Cu NPs to the second impregnation bath significantly decreases the turbidity time values. To avoid these changes in the gel time and turbidity values, the amount of catalyst used in the mixtures of both should be reduced. impregnation baths and additionally the use of a buffer in the resin can be considered. In cases where the turbidity times are low (of the order of 4' to 4'30”), no type of buffer is required and only by reducing the amount of catalyst is the objective of maintaining the gel time and/or turbidity values within the normal operating ranges of the plants.
Ejemplo 2: Example 2:
• Se preparar una solución de NPs de Cu con una concentración de 10.000 ppm, donde el tamaño de las nanopartículas está entre 7 y 8 nm y el medio líquido comprende un agente estabilizante. • A solution of Cu NPs with a concentration of 10,000 ppm will be prepared, where the size of the nanoparticles is between 7 and 8 nm and the liquid medium comprises a stabilizing agent.
• Se prepara un primer baño de impregnación el cual comprende una resina de urea-formaldehído (UF) y aditivos seleccionados de agentes humectantes (tales como Deurowet MA11 , Alton WLF 14), catalizadores (tales como DeuroCure FC, Alton HM 1448) y agentes anti-blocking (tales como DeuroSlide FA) (mezcla 1 ) los cuales confieren propiedades al papel para evitar su aglomeración y/o facilitar el paso de la resina al centro del papel. La cantidad de agente humectante se encuentra en el rango de 0,1 % a 0,5% p/p con respecto a la resina UF; la cantidad de catalizador se encuentra en el rango de 0,1 a 0,4% p/p con respecto a la resina UF; y la cantidad de agente anti-blocking se encuentra en el rango de 0,1 % a 0,5% p/p con respecto a la resina UF. Se regula el tiempo gel de la resma ajustando la cantidad de catalizador utilizado, tal que el valor del tiempo gel se encuentre en un rango de 2’30” a 3’. • A first impregnation bath is prepared which comprises a urea-formaldehyde (UF) resin and additives selected from wetting agents (such as Deurowet MA11, Alton WLF 14), catalysts (such as DeuroCure FC, Alton HM 1448) and agents. anti-blocking (such as DeuroSlide FA) (mixture 1) which confer properties to the paper to prevent its agglomeration and/or facilitate the passage of the resin to the center of the paper. The amount of wetting agent is in the range of 0.1% to 0.5% w/w with respect to the UF resin; the amount of catalyst is in the range of 0.1 to 0.4% w/w with respect to the UF resin; and the amount of anti-blocking agent is in the range of 0.1% to 0.5% w/w with respect to the UF resin. The gel time is regulated the rest by adjusting the amount of catalyst used, such that the value of the gel time is in a range of 2'30” to 3'.
• Se preparan dos segundos baños de impregnación, donde uno de los segundos baños de impregnación contiene la solución de NPs de Cu en la concentración de 10.000 ppm (sólo para la cara superior del papel) y el otro no (para la cara inferior del papel). Estos baños comprenden una resina melamina-formaldehído (MF), aditivos seleccionados de agentes desmoldantes (tales como DeuroLease PHO, Alton R 1014), agentes antipolvo (tales como DeuroChem ADV, Alton ES 700), catalizadores (tales como DeuroCure KS-XL, Alton HM 1010). La cantidad de NPs de Cu utilizada en el segundo baño de impregnación que las contiene es de 10 g de NPs de Cu por kg de resina MF líquida (mezcla 2). La cantidad de agente desmoldante se encuentra en el rango de 0,1 % a 0,6% p/p con respecto a la resina MF; la cantidad de catalizador se encuentra en el rango de 0,1 a 0,4% p/p con respecto a la resina MF; y la cantidad de surfactante se encuentra en el rango de 0,05% a 0,3% p/p con respecto a la resina MF. Se regula el tiempo de turbidez de la resina ajustando la cantidad de catalizador utilizado tal que el valor se encuentre en un rango de 6’ a 6’30”. • Two second impregnation baths are prepared, where one of the second impregnation baths contains the Cu NPs solution at a concentration of 10,000 ppm (only for the upper face of the paper) and the other does not (for the lower face of the paper). ). These baths comprise a melamine-formaldehyde (MF) resin, additives selected from mold release agents (such as DeuroLease PHO, Alton R 1014), anti-dust agents (such as DeuroChem ADV, Alton ES 700), catalysts (such as DeuroCure KS-XL, Alton HM 1010). The amount of Cu NPs used in the second impregnation bath that contains them is 10 g of Cu NPs per kg of liquid MF resin (mix 2). The amount of release agent is in the range of 0.1% to 0.6% w/w with respect to the MF resin; the amount of catalyst is in the range of 0.1 to 0.4% w/w with respect to the MF resin; and the amount of surfactant is in the range of 0.05% to 0.3% w/w with respect to the MF resin. The turbidity time of the resin is regulated by adjusting the amount of catalyst used so that the value is in a range of 6' to 6'30".
• Se impregna un papel blanco de gramaje 80 g/m2 en el primer baño de impregnación, agregando una cantidad de la mezcla 1 tal que el peso (gramaje) final del papel con la resina y los aditivos sea de 145 g/m2 en peso seco (papel más resina). • A white paper with a weight of 80 g/m 2 is impregnated in the first impregnation bath, adding an amount of mixture 1 such that the final weight (gram weight) of the paper with the resin and the additives is 145 g/m 2 dry weight (paper plus resin).
• Se seca el papel mediante un secador por etapas con aire forzado con temperaturas en el rango de 100 a 220°C a una velocidad de 50 m/min, hasta alcanzar una humedad de 12% a 14%. • Se vuelve a impregnar el papel resultante en los segundos baños de impregnación, donde para la cara superior se impregna en el segundo baño de impregnación que contiene las NPs de Cu y para la cara inferior se impregna en el segundo baño de impregnación que no las contiene. Se agrega una cantidad total (de resina + aditivos) tal que el peso (gramaje) final del papel con la resina y los aditivos sea de 185 g/m2 en peso seco (papel más resina). • The paper is dried by means of a dryer in stages with forced air with temperatures in the range of 100 to 220°C at a speed of 50 m/min, until reaching a humidity of 12% to 14%. • The resulting paper is impregnated again in the second impregnation baths, where the upper face is impregnated in the second impregnation bath that contains the Cu NPs and the lower face is impregnated in the second impregnation bath that does not contain them. contains. A total amount (of resin + additives) is added such that the final weight (grammage) of the paper with the resin and the additives is 185 g/m 2 in dry weight (paper plus resin).
• Se seca el papel por segunda vez mediante un secador por etapas con aire forzado con temperaturas en el rango de 100 a 220°C a una velocidad de 50 m/min. Los parámetros de la temperatura del homo y la velocidad de la línea de papel son ajustados tal que la humedad a la salida del papel esté en un rango de 4,5 a 5%. • The paper is dried a second time by a forced air stage dryer with temperatures in the range of 100 to 220°C at a speed of 50 m/min. The parameters of the oven temperature and the speed of the paper line are adjusted so that the humidity at the paper outlet is in a range of 4.5 to 5%.
• Se prensa el papel impregnado resultante sobre el tablero aglomerado (PB) en una prensa caliente a una presión específica de prensado entre 20 y 50 kg/cm2 y una temperatura entre 170°C y 220°C, durante un tiempo que varía entre 9 y 25 segundos con el propósito de obtener una superficie melaminizada uniforme. • The resulting impregnated paper is pressed onto the chipboard (PB) in a hot press at a specific pressing pressure between 20 and 50 kg/cm2 and a temperature between 170°C and 220°C, for a time that varies between 9 and 25 seconds in order to obtain a uniform melamine surface.
• Una vez finalizado el tablero melaminizado, se evalúa su calidad según análisis en laboratorio incluyendo capacidad antimicrobiana en S. aureus y E. coli, test de ácido, grafito, dureza superficial, diferencias en el color y resistencia a la abrasión. • Once the melamine board is finished, its quality is evaluated according to laboratory analysis including antimicrobial capacity in S. aureus and E. coli, acid test, graphite, surface hardness, differences in color and resistance to abrasion.
En la figura 3 se puede apreciar que al aplicar NPs de Cu únicamente a la cara superior del papel, los resultados muestran una alta eficiencia antibacteriana del tablero, siendo para todos los casos sobre un 99,5% a las 2 horas y sobre un 99,9% desde las 6 horas en adelante. Eiemplo 3: In figure 3 it can be seen that when applying Cu NPs only to the upper face of the paper, the results show a high antibacterial efficiency of the board, being for all cases over 99.5% at 2 hours and over 99 .9% from 6 hours onwards. Example 3:
Se sometieron a 2 cepas, Escherichia coli ATCC 25922 y Staphylococcus aureus ATCC 25923, 84 muestras de tableros melaminicos de 6x6 cm de tamaño con las siguientes características: 84 samples of 6x6 cm melamine boards with the following characteristics were subjected to 2 strains, Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923:
Color Blanco: White color:
• Prueba A (aplicación de NPs de Cu en cara superior del papel): 30 muestras de 12 mm de alto aproximado • Test A (application of Cu NPs on the upper face of the paper): 30 samples of approximately 12 mm height
• Prueba B (aplicación de NPs de Cu en ambas caras del papel): 30 muestras de 12 mm de alto aproximado • Test B (application of Cu NPs on both sides of the paper): 30 samples approximately 12 mm high
• Control (sin NPs de Cu): 24 muestras de 12 mm de alto aproximado • Control (without Cu NPs): 24 samples of approximately 12 mm height
Las muestras fueron evaluadas a las 2 y 24 horas de incubación a 35°C (humedad relativa mayor a 90%). The samples were evaluated after 2 and 24 hours of incubation at 35°C (relative humidity greater than 90%).
El volumen inoculado en cada una de las muestras fue de 400 pl y se utilizó un Standard McFarland 0,5 para obtener una concentración de 1 ,0x106 UFC/ml en cada una de las cepas utilizadas. The inoculated volume in each of the samples was 400 pl and a McFarland 0.5 Standard was used to obtain a concentration of 1.0x10 6 CFU/ml in each of the strains used.
Las bacterias fueron recuperadas utilizando pinzas estériles para agregar el film a un tubo con 10 mi de medio SCDLP y luego se recogió la muestra utilizando trozos de tela KIMTECH WS (50% Rayon/50% Polyester) esterilizadas en pupinel. The bacteria were recovered using sterile tweezers to add the film to a tube with 10 ml of SCDLP medium and then the sample was collected using pieces of KIMTECH WS cloth (50% Rayon/50% Polyester) sterilized in pupinel.
En la Tabla 1 se puede apreciar el promedio del recuento de E. coli y S. aureusen (UFC/cm2) y logaritmo en base 10 de las muestras analizadas.
Figure imgf000017_0001
Table 1 shows the average count of E. coli and S. aureusen (CFU/cm 2 ) and the base 10 logarithm of the analyzed samples.
Figure imgf000017_0001
Se puede apreciar a partir de la Tabla 1 que, a las 24 horas, no se logra apreciar un conteo de las bacterias en las muestras A y B de la invención. En la Tabla 2 se aprecia la actividad antibacteriana de las muestras evaluadas después de 2 y 24 horas de incubación para las 2 cepas utilizadas y porcentaje de reducción del recuento en UFC/cm2 comparando cada una de las muestras con y sin tratamiento. It can be seen from Table 1 that, at 24 hours, no count of bacteria can be seen in samples A and B of the invention. Table 2 shows the antibacterial activity of the samples evaluated after 2 and 24 hours of incubation for the 2 strains used and the percentage of count reduction in CFU/cm 2 comparing each of the samples with and without treatment.
Figure imgf000018_0001
Figure imgf000018_0001
Después de 2 horas de incubación, se tiene más de un 95% de reducción del recuento bacteriano para ambas cepas inoculadas. Por su parte después de 24 horas de incubación, ambas cepas presentan un 100% de reducción en el recuento bacteriano. After 2 hours of incubation, there is a greater than 95% reduction in bacterial count for both inoculated strains. On the other hand, after 24 hours of incubation, both strains show a 100% reduction in the bacterial count.
En la figura 4 se puede observar que no existen diferencias significativas de color (AE < 1 ,0) al utilizar NPs de cobre en papel blanco impregnado si se utiliza en el rango estipulado. Figure 4 shows that there are no significant color differences (AE < 1.0) when using copper NPs in impregnated white paper if used in the stipulated range.
Por su parte en la figura 5 se puede apreciar que existe un aumento significativo de la reactividad de la resina al utilizar NPs de cobre, donde se debe modificar la cantidad de catalizador (3 veces menos, equivalente a un 33% de la aplicación estándar) para obtener valores similares al grupo estándar. For its part, in figure 5 it can be seen that there is a significant increase in the reactivity of the resin when using copper NPs, where the amount of catalyst must be modified (3 times less, equivalent to 33% of the standard application) to obtain values similar to the standard group.
La figura 6 corresponde a un ejemplo donde se observaron las variaciones en el tiempo de turbidez (TT) al cambiar la cantidad de catalizador (0%, 0,1 %, 0,2% y 0,3%) y búfer (thetanolamina (TEA), 0,2%, 0,35%, 0,5%) en la resina MF. Se determina que la condición óptima en este caso (rango de TT entre 4’30” y 4’50”, entre el límite inferior (LCI) y el límite superior (LCS)) sería utilizando una adición de 0,35% p/p de trietanolamina y de 0,25% p/p de catalizador respecto a resina MF. Figure 6 corresponds to an example where the variations in the turbidity time (TT) were observed when changing the amount of catalyst (0%, 0.1%, 0.2% and 0.3%) and buffer (theethanolamine ( TEA), 0.2%, 0.35%, 0.5%) in the MF resin. It is determined that the optimal condition in this case (TT range between 4'30” and 4'50”, between the lower limit (LCI) and the upper limit (LCS)) would be using an addition of 0.35% w/w triethanolamine and 0.25% w/w catalyst relative to MF resin.
Ventajas de la invención: Advantages of the invention:
La presente invención consigue la producción de un tablero melaminizado con propiedades antimicrobianas conferidas por el cobre presente en forma de NPs. La adición de estas NPs en solución como aditivo de impregnación permite una alta eficiencia antimicrobiana a bajas concentraciones, lo que permite operar el proceso de manera normal sin modificaciones significativas. A través de la presente invención se logra obtener tableros melaminizados tan difíciles como el negro y el grafito, sin presentar problemas de calidad. Además, en tableros espresso no se observan manchas brillantes con el uso de las NPs de Cu. The present invention achieves the production of a melamine board with antimicrobial properties conferred by the copper present in the form of NPs. The addition of these NPs in solution as an impregnation additive allows a high antimicrobial efficiency at low concentrations, which allows the process to operate normally without significant modifications. Through the present invention it is possible to obtain melamine boards as difficult as black and graphite, without presenting quality problems. Furthermore, in espresso boards no bright spots are observed with the use of Cu NPs.

Claims

REIVINDICACIONES
1. Un proceso de impregnación de papel para recubrir tableros de madera con un efecto antimicrobiano, que evita la interferencia con el color final del papel, CARACTERIZADO porque comprende: a) preparar (13) una dispersión (14) de nanopartículas de cobre (NPs de Cu, 11 ) con un tamaño de partículas entre 0,1 nm y 20 nm en un medio líquido (12); b) preparar una mezcla 1 (23) que será utilizada en un primer baño de impregnación (32), la cual comprende una o más resinas (21 ) seleccionada de: UF, MF, MUF o una mezcla de las mismas y uno o más aditivos (22) seleccionados de: catalizadores, agentes humectantes, tampones o búfers y agentes anti-blocking; c) preparar una mezcla 2 (26) que será utilizada en un segundo baño de impregnación (36) o posteriores, la cual comprende una resina (24) MF y uno o más aditivos (25) seleccionados de catalizadores, agentes humectantes, agentes antipolvo, agentes desmoldantes, agentes antiblocking y tampones o búfers; d) agregar la dispersión de NPs de Cu (14) a la mezcla 1 (23), o a la mezcla 2 (26), o a ambas mezclas; e) impregnar un papel (31 ) con un gramaje entre 35 a 120 g/m2, en un primer baño de impregnación (32) que comprende la mezcla 1 (23), alcanzando una carga de resina (peso seco más papel) entre 100 a 220 g/m2; f) secar el papel impregnado (33) en el primer baño de impregnación (32) en una etapa de secado (34); g) impregnar el papel secado (35) en un segundo baño de impregnación (36) que comprende la mezcla 2 (26), alcanzando una carga final de resina (peso seco más papel) entre 120 a 260 g/m2; h) secar el papel impregnado (37) en el segundo baño de impregnación (36) en una última etapa de secado (38); i) prensar (41 ) el papel resultante (39) de la etapa de secado sobre un sustrato, tal como un tablero en base a madera; j) cortar (42) el papel del tamaño del tablero de madera. 1. A paper impregnation process to coat wooden boards with an antimicrobial effect, which prevents interference with the final color of the paper, CHARACTERIZED because it comprises: a) preparing (13) a dispersion (14) of copper nanoparticles (NPs of Cu, 11) with a particle size between 0.1 nm and 20 nm in a liquid medium (12); b) prepare a mixture 1 (23) that will be used in a first impregnation bath (32), which comprises one or more resins (21) selected from: UF, MF, MUF or a mixture thereof and one or more additives (22) selected from: catalysts, wetting agents, buffers and anti-blocking agents; c) prepare a mixture 2 (26) that will be used in a second impregnation bath (36) or later, which comprises an MF resin (24) and one or more additives (25) selected from catalysts, wetting agents, anti-dust agents , mold release agents, antiblocking agents and buffers; d) add the dispersion of Cu NPs (14) to mixture 1 (23), or to mixture 2 (26), or to both mixtures; e) impregnate a paper (31) with a grammage between 35 and 120 g/m 2 , in a first impregnation bath (32) comprising mixture 1 (23), reaching a resin load (dry weight plus paper) between 100 to 220 g/m 2 ; f) drying the impregnated paper (33) in the first impregnation bath (32) in a drying step (34); g) impregnating the dried paper (35) in a second impregnation bath (36) comprising mixture 2 (26), reaching a final resin load (dry weight plus paper) between 120 and 260 g/m 2 ; h) drying the impregnated paper (37) in the second impregnation bath (36) in a final drying stage (38); i) pressing (41) the resulting paper (39) from the drying stage on a substrate, such as a wood-based board; j) cutting (42) the paper to the size of the wooden board.
2. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque las NPs de Cu (11 ) tienen un nivel de pureza mayor a 95% en una concentración de 1 .000 a 10.000 ppm. 2. The impregnation process of claim 1, CHARACTERIZED in that the Cu NPs (11) have a purity level greater than 95% at a concentration of 1,000 to 10,000 ppm.
3. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque el medio líquido (12) se selecciona de uno o varios solventes, incluyendo agua, iones, solventes polares, solventes no-polares, solventes orgánicos, solventes inorgánicos, aceites, surfactantes, dispersantes, estabilizantes o entrecruzantes. 3. The impregnation process of claim 1, CHARACTERIZED in that the liquid medium (12) is selected from one or more solvents, including water, ions, polar solvents, non-polar solvents, organic solvents, inorganic solvents, oils, surfactants, dispersants, stabilizers or crosslinkers.
4. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque la cantidad de aditivos (22) en la mezcla4. The impregnation process of claim 1, CHARACTERIZED in that the amount of additives (22) in the mixture
1 (23) es de 0,1 % - 0,4% p/p de catalizador; 0,1 % - 0,5% p/p de agente humectante; 0,2% - 0,8% p/p de tampón o búfer; y 0,1 % - 0,5% p/p de agente anti-blocking con respecto a la resina. 1 (23) is 0.1% - 0.4% w/w catalyst; 0.1% - 0.5% w/w wetting agent; 0.2% - 0.8% w/w buffer or buffer; and 0.1% - 0.5% w/w of anti-blocking agent with respect to the resin.
5. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque la cantidad de aditivos (25) en la mezcla5. The impregnation process of claim 1, CHARACTERIZED in that the amount of additives (25) in the mixture
2 (25) es de 0,1 % - 0,4% p/p de catalizador; 0,1 % - 0,5% p/p de agente humectante; 0,05% - 0,3% p/p de agente antipolvo; 0,1 % - 0,6% p/p de agente desmoldante; 0,1 % - 0,5% p/p de agente antiblocking; y 0,2% - 0,8% p/p de tampón o búfer con respecto a la resina. 2 (25) is 0.1% - 0.4% w/w catalyst; 0.1% - 0.5% w/w wetting agent; 0.05% - 0.3% w/w anti-dusting agent; 0.1% - 0.6% w/w release agent; 0.1% - 0.5% w/w antiblocking agent; and 0.2% - 0.8% w/w buffer or buffer relative to resin.
6. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque la cantidad de resina total (21 , 24) en el sistema corresponde a un 50% - 60% en relación al peso total del papel formado. 6. The impregnation process of claim 1, CHARACTERIZED in that the amount of total resin (21, 24) in the system corresponds to 50% - 60% in relation to the total weight of the formed paper.
7. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque la cantidad de resina (24) en la mezcla 2 (26) es de 30 - 50 g/m2 (gramos de resina por metro cuadrado de resina MF). 7. The impregnation process of claim 1, CHARACTERIZED in that the amount of resin (24) in mixture 2 (26) is 30-50 g/m 2 (grams of resin per square meter of MF resin).
8. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque la cantidad de NPs de Cu (14) se encuentra en un rango entre 0,001 % y 0,005% en peso seco de NPs de Cu respecto a la resina utilizada. 8. The impregnation process of claim 1, CHARACTERIZED in that the amount of Cu NPs (14) is in a range between 0.001% and 0.005% dry weight of Cu NPs with respect to the resin used.
9. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque en la etapa (f), la etapa de secado (34) se realiza con aire forzado en un secador por etapas a temperaturas que fluctúan en un rango entre 100 a 220°C, hasta alcanzar una humedad de al menos 12%. 9. The impregnation process of claim 1, CHARACTERIZED in that in stage (f), the drying stage (34) is carried out with forced air in a staged dryer at temperatures that fluctuate in a range between 100 to 220 ° C , until reaching a humidity of at least 12%.
10. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque el tiempo de impregnación del papel en el primer baño de impregnación (32) y en el segundo baño de impregnación (36) depende de la velocidad con la cual pasa el papel a través de este baño, donde la velocidad se encuentra en un rango de 20 m/min a 90 m/min. 10. The impregnation process of claim 1, CHARACTERIZED in that the impregnation time of the paper in the first impregnation bath (32) and in the second impregnation bath (36) depends on the speed with which the paper passes through of this bath, where the speed is in a range of 20 m/min to 90 m/min.
11. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque en la etapa (h), la etapa de secado (38) se realiza con aire forzado en un secador por etapas a temperaturas que fluctúan en un rango entre 100 a 220°C, hasta alcanzar una humedad inferior a 6%. 11. The impregnation process of claim 1, CHARACTERIZED in that in stage (h), the drying stage (38) is carried out with forced air in a staged dryer at temperatures ranging from 100 to 220 ° C , until reaching a humidity of less than 6%.
12. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque opcionalmente existen baños de impregnación posteriores al segundo baño (36), seguido de etapas de secado posteriores. 12. The impregnation process of claim 1, CHARACTERIZED in that there are optionally impregnation baths subsequent to the second bath (36), followed by subsequent drying stages.
13. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque el papel impregnado con NPs de Cu (39) obtenido de la etapa (h) posee una humedad en un rango de 4% a 6%. 13. The impregnation process of claim 1, CHARACTERIZED in that the paper impregnated with Cu NPs (39) obtained from stage (h) has a humidity in a range of 4% to 6%.
14. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque la velocidad del proceso durante la impregnación y secado está en un rango de entre 20 a 90 m/min (avance del papel en la línea). 14. The impregnation process of claim 1, CHARACTERIZED in that the speed of the process during impregnation and drying is in a range between 20 to 90 m/min (advance of the paper in the line).
15. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque en la etapa (i) la presión especifica de prensado varía entre 20 y 50 kg/cm2, la temperatura se encuentra entre 170°C y 220°C y el tiempo de prensado varía entre 9 y 25 segundos. 15. The impregnation process of claim 1, CHARACTERIZED in that in stage (i) the specific pressing pressure varies between 20 and 50 kg/cm 2 , the temperature is between 170°C and 220°C and the time of pressing varies between 9 and 25 seconds.
16. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque opcionalmente el papel resultante (39) de la etapa de secado es almacenado (43) en racks (44) para su posterior uso. 16. The impregnation process of claim 1, CHARACTERIZED in that the resulting paper (39) from the drying stage is optionally stored (43) in racks (44) for later use.
17. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque en la etapa (d), la dispersión de NPs de Cu (14) se agrega a la mezcla 2 (26) que será utilizada en el segundo baño de impregnación. 17. The impregnation process of claim 1, CHARACTERIZED in that in step (d), the Cu NPs dispersion (14) is added to mixture 2 (26) that will be used in the second impregnation bath.
18. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque el tampón o búfer se selecciona de thetanolamina y bórax. 18. The impregnation process of claim 1, CHARACTERIZED in that the buffer or buffer is selected from theethanolamine and borax.
19. El proceso de impregnación de la reivindicación 1 , CARACTERIZADO porque el tampón o búfer se adiciona a la mezcla con NPs de Cu. 19. The impregnation process of claim 1, CHARACTERIZED in that the buffer is added to the mixture with Cu NPs.
22 22
PCT/CL2020/050189 2020-11-09 2020-12-22 Paper impregnation method with antimicrobial effect, for covering wooden boards WO2022094735A1 (en)

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