EP1636422A1 - Microspheres - Google Patents

Microspheres

Info

Publication number
EP1636422A1
EP1636422A1 EP04735699A EP04735699A EP1636422A1 EP 1636422 A1 EP1636422 A1 EP 1636422A1 EP 04735699 A EP04735699 A EP 04735699A EP 04735699 A EP04735699 A EP 04735699A EP 1636422 A1 EP1636422 A1 EP 1636422A1
Authority
EP
European Patent Office
Prior art keywords
paper
expandable microspheres
microspheres
propellant
fibres
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP04735699A
Other languages
German (de)
French (fr)
Inventor
Anna Kron
Örjan Söderberg
Ingela Eriksson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Akzo Nobel NV
Original Assignee
Akzo Nobel NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Akzo Nobel NV filed Critical Akzo Nobel NV
Priority to EP04735699A priority Critical patent/EP1636422A1/en
Publication of EP1636422A1 publication Critical patent/EP1636422A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/02Making microcapsules or microballoons
    • B01J13/06Making microcapsules or microballoons by phase separation
    • B01J13/14Polymerisation; cross-linking
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP 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
    • D21H21/00Non-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
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/16Making expandable particles
    • C08J9/18Making expandable particles by impregnating polymer particles with the blowing agent
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP 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
    • D21H21/00Non-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
    • D21H21/50Non-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 form
    • D21H21/52Additives of definite length or shape
    • D21H21/54Additives of definite length or shape being spherical, e.g. microcapsules, beads
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP 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
    • D21H27/00Special paper not otherwise provided for, e.g. made by multi-step processes
    • D21H27/30Multi-ply

Definitions

  • the present invention relates to a process for the production of paper or nonwoven and thermoplastic expandable microspheres useful therefore.
  • Expandable thermoplastic microspheres comprising a thermoplastic polymer shell and a propellant entrapped therein are commercially available under the trademark EXPANCEL ® and are used as a foaming agent in many different applications.
  • the propellant is normally a liquid having a boiling temperature not higher than the softening temperature of the thermoplastic polymer shell. Upon heating, the propellant evaporates to increase the internal pressure at the same time as the shell softens, resulting in significant expansion of the microspheres.
  • the temperature at which the expansion starts is called T start> while the temperature at which maximum expansion is reached is called T ma ⁇ .
  • Expandable microspheres are marketed in various forms, e.g. as dry free flowing particles, as an aqueous slurry or as a partially dewatered wet-cake. Expandable microspheres can be produced by polymerising ethylenically unsaturated monomers in the presence of a propellant. Detailed descriptions of various expandable microspheres and their production can be found in, for example, US Patents 3615972, 3945956, 5536756, 6235800, 6235394 and 6509384, and in EP 486080.
  • the invention thus concerns use of thermally expandable microspheres comprising a thermoplastic polymer shell and from about 17 to about 40 wt%, preferably from about 18 to about 40 wt%, most preferably from about 19 to about 40 wt%, particularly most preferably from about 20 to about 35 wt% of a propellant entrapped in said polymer shell, and having a volume-average diameter from about 17 to about 35 ⁇ m, preferably from about 18 to about 35 ⁇ m, more preferably from about 19 to about 35 ⁇ m, most preferably from about 20 to about 30 ⁇ m, particularly most preferably from about 21 to about 30 ⁇ m, in the production of paper or non-woven for increasing the bulk thereof.
  • expandable microspheres refers to expandable microspheres that have not previously been expanded, i.e. unexpanded expandable microspheres.
  • volume-average diameter refers to values obtained by measuring according to ISO 13319:2000, "Determination of particle size distributions - Electrical sensing zone method". Detailed description of this measuring method can be obtained from, for example, Swedish Institute For Standards, Sweden.
  • the invention further concerns a process for the production of paper or nonwoven from fibres comprising the steps of adding thermally expandable microspheres comprising a thermoplastic polymer shell and a propellant entrapped therein to a stock comprising fibres or to a web of fibres, forming paper or nonwoven from the stock or the web, and applying heat to raise the temperature of the microspheres sufficiently for them to expand and thereby increase the bulk of the paper or the nonwoven.
  • the expandable microspheres have a volume-average diameter from about 17 to about 35 ⁇ m, preferably from about 18 to about 35 ⁇ m, more preferably from about 19 to about 35 ⁇ m, most preferably from about 20 to about 30 ⁇ m, particularly most preferably from about 21 to about 30 ⁇ m.
  • the amount of propellant in the expandable microspheres is from about 17 to about 40 wt%, preferably from about 18 to about 40 wt%, most preferably from about 19 to about 40 wt%, particularly most preferably from about 20 to about 35 wt%.
  • An embodiment of the invention concerns a process for the production of paper comprising the steps of adding expandable microspheres as described above to a stock containing cellulosic fibres, dewatering the stock on a wire to obtain paper, and drying the paper by applying heat and thereby also raising the temperature of the microspheres sufficiently for them to expand and increase the bulk of the paper.
  • the expandable microspheres may be added separately or together with one or more other additive used in the papermaking process.
  • the expandable microspheres can be added in any form, although it from a practical point of view is most preferred to add them in the form of an aqueous slurry, preferably having a solids content from about 5 to about 55 wt %, most preferably from about 40 to about 50 wt%.
  • the slurry preferably also comprises a thickener compatible with paper making, such as anionic or cationic starch, optionally in combination with a salt such as sodium chloride.
  • a thickener compatible with paper making such as anionic or cationic starch
  • a salt such as sodium chloride.
  • Starch may, for example, be present in the slurry in an amount from about 0.1 to about 5 wt%, preferably from about 0.3 to about 1.5 wt%.
  • Sodium chloride, or another salt may, for example, be present in the slurry in an amount from about 0.1 to about 20 wt%, preferably from about 1 to about 15 wt%.
  • the amount of expandable microspheres added to the stock is preferably from about 0.1 to about 20 wt%, most preferably from about 0.2 to about 10 wt% dry microspheres of the dry content in the stock. Any kind of paper machine known in the art can be used.
  • paper is meant to include all types of cellulose-based products in sheet or web form, including, for example, board, cardboard and paperboard.
  • the invention has been found particularly advantageous for the production of board, cardboard and paper board, particularly with a basis weight from about 50 to about 1000 g/m 2 , preferably from about 150 to about 800 g/m 2 .
  • the paper may be produced as a single layer or a multi-layer paper. If the paper comprises three or more layers, the expandable microspheres are preferably not added to the portion of the stock forming any of the two outer layers.
  • the stock preferably contains from about 50 to about 100 wt%, most preferably from about 70 to about 100 wt% of cellulosic fibres, based on dry material. Before dewatering, the stock besides expandable microspheres, may also contain one or more fillers, e.g.
  • mineral fillers like kaolin, china clay, titanium dioxide, gypsum, talc, chalk, ground marble or precipitated calcium carbonate, and optionally other commonly used additives, such as retention aids, sizing agents, aluminium compounds, dyes, wet-strength resins, optical brightening agents, etc.
  • aluminium compounds include alum, alumina- tes and polyaluminium compounds, e.g. polyaluminium chlorides and sulphates.
  • retention aids include cationic polymers, anionic inorganic materials in combination with organic polymers, e.g. bentonite in combination with cationic polymers or silica-based sols in combination with cationic polymers or cationic and anionic polymers.
  • sizing agents include cellulose reactive sizes such as alkyl ketene dimers and alkenyl succinic anhydride, and cellulose non-reactive sizes such as rosin, starch and other polymeric sizes like copolymers of styrene with vinyl monomers such as maleic anhydride, acrylic acid and its alkyl esters, acrylamide, etc.
  • the paper, and thereby also the microspheres is preferably heated to a temperature from about 50 to about 150°C, most preferably from about 60 to about 110°C. This results in expansion of the microspheres and thereby also a bulk increase of the paper.
  • the magnitude of this bulk increase depends on various factors, such as the origin of cellulosic fibres and other components in the stock, but is in most cases from about 5 to about 50 % per weight percentage of retained microspheres in the dried paper, compared to the same kind of paper produced without addition of expandable microspheres or any other expansion agent.
  • Any conventional means of drying involving transferring heat to the paper can be applied, such as contact drying (e.g. by heated cylinders), forced convection drying (e.g. by hot air), infrared techniques, or combinations thereof.
  • contact drying e.g. by heated cylinders
  • forced convection drying e.g. by hot air
  • infrared techniques or combinations thereof.
  • the temperature of the contact surfaces e.g. the cylinders
  • the paper may pass a series of several cylinders, e.g. up to 20 or more, of increasing temperature.
  • the cellulosic fibres in the stock may, for example, come from pulp made from any kind of plants, preferably wood, such as hardwood and softwood.
  • the cellulosic fibres may also partly or fully originate from recycled paper, in which case the invention has been found to give unexpectedly good results.
  • Another embodiment of the invention concerns a process for the production of nonwoven comprising the steps of forming a web of fibres, adding to said web a binder and expandable microspheres as described above, and forming nonwoven and applying heat to raise the temperature of the microspheres sufficiently for them to expand and thereby increase the bulk nonwoven.
  • the expandable microspheres and the binder may be added separately or as a mixture.
  • the amount of expandable microspheres added is preferably from about 0.1 to about 30 wt% of dried product, most preferably from about 0.5 to about 15 wt% of dried product.
  • the amount of binder added is preferably from about 10 to about 90 wt% of dried product, most preferably from about 20 to about 80 wt% of dried product.
  • nonwoven as used herein is meant to include textiles made from fibres bonded together by means of a binder.
  • the web of fibres can be formed in any conventional way, for example by mechanical or aerodynamical dry methods, hydrodynamical (wet) methods, or spunbonded processes.
  • the binder preferably pre-mixed with expandable microspheres, can then be added to the web also in any conventional way, for example by any kind of impregnation method such as immersion of the web in a bath of binder or coating the web by kiss roll application or knife coating with a doctor blade or floating knife.
  • the web comprising a binder and expandable microspheres can then be heated to a temperature sufficient for the microspheres to expand, preferably from about 70 to about 200°C, most preferably from about 120 to about 160°C.
  • a temperature sufficient for the microspheres to expand preferably from about 70 to about 200°C, most preferably from about 120 to about 160°C.
  • curing of the binder takes place at the same time.
  • the heating can be effected by any suitable means, such as contact drying (e.g. by heated cylinders), forced convection drying (e.g. by hot air), infrared techniques, or combinations thereof.
  • the fibres can be any kind of commercially available fibres, natural fibres, mineral fibres, as well as synthetic inorganic and organic fibres.
  • useful fibres include polypropylene, polyethylene, polyester, viscose, and polyamide fibres, as well as fibres made from two or more of the above polymers.
  • the binder can be any kind of natural or synthetic adhesive resin, such as resins of polyacrylates and co-polymers thereof, polymethacrylates and co-polymers thereof, rubber latexes such as styrene/butadiene copolymers, acrylonitrile/butadiene copolymers, poly(vinyl chloride) and copolymers, poly(vinyl ester) such as poly(vinyl acetate) and co- polymers, e.g. with ethylene, poly(vinyl alcohol), polyurethane, and aminoplast and phenoplast precondensates such as urea/ formaldehyde, urea/ melamine / formaldehyde or phenol/ formaldehyde.
  • adhesive resin such as resins of polyacrylates and co-polymers thereof, polymethacrylates and co-polymers thereof, rubber latexes such as styrene/butadiene copolymers, acrylonitrile/buta
  • thermoplastic polymer shell of the expandable microspheres is suitably made of a homo- or co-polymer obtained by polymerising ethylenically unsaturated monomers.
  • Those monomers can, for example, be nitrile containing monomers such as acrylonitrile, methacrylonitrile, ⁇ -chloroacrylonitrile, -ethoxyacrylonitrile, fumaronitrile or crotonitrile; acrylic esters such as methyl acrylate or ethyl acrylate; methacrylic esters such as methyl methacrylate, isobornyl methacrylate or ethyl methacrylate; vinyl halides such as vinyl chloride; vinyl esters such as vinyl acetate other vinyl monomers such as vinyl pyridine; vinylidene halides such as vinylidene chloride; styrenes such as styrene, halogenated styrenes or ⁇ -methyl styrene; or dienes such as butadiene, isoprene and chloroprene.
  • monomers such as acrylonitrile, methacrylonitrile, ⁇ -chloroacrylon
  • the monomers comprise at least one acrylic ester or methacrylic ester monomer, most preferably methacrylic ester monomer such as methyl methacrylate.
  • the amount thereof in the polymer shell is preferably from about 0.1 to about 80 wt%, most preferably from about 1 to about 25 wt% of the total amounts of monomers.
  • the monomers comprise at least one vinylidene halide monomer, most preferably vinylidene chloride.
  • the amount thereof in the polymer shell is preferably from about 1 to about 90 wt%, most preferably from about 20 to about 80 wt% of the total amounts of monomers.
  • the monomers comprise both at least one acrylic ester or methacrylic ester monomer and at least one vinylidene halide monomer.
  • the monomers comprise at least one nitrile containing monomer, most preferably at least one of acrylonitrile and methacrylonitrile, particularly most preferably at least acrylonitrile.
  • the amount thereof in the polymer shell is preferably from about 1 to about 80 wt%, most preferably from about 20 wt% to about 70 wt% of the total amounts of monomers.
  • the monomers comprise at least one acrylic ester monomer, at least one vinylidene halide and at least one nitrile containing monomer.
  • the polymer shell may then, for example, be a co-polymer obtained from monomers comprising methyl methacrylate in a preferred amount from about 0.1 to about
  • 80 wt% most preferably from about 1 to about 25 wt% of the total amounts of monomers, vinylidene chloride in a preferred amount from about 1 to about 90 wt%, most preferably from about 20 to about 80 wt% of the total amounts of monomers, and acrylonitrile in a preferred amount from about 1 to about 80 wt%, most preferably from about 20 to about
  • the monomers for the polymer shell also comprise crosslinking multifunctional monomers, such as at least one of divinyl benzene, ethylene glycol di(meth)acrylate, di(ethylene glycol) di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1 ,4-butanediol di(meth)acrylate, 1 ,6- hexanediol di(meth)acrylate, glycerol di(meth)acrylate, 1 ,3-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1 ,10-decanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, triallylformal tri(meth)acrylate, allyl me
  • the amount thereof in the polymer shell is preferably from about 0.1 to about 10 wt%, most preferably from about 0.1 to about 1 wt%, particularly most preferably from about 0.2 to about 0.5 wt% of the total amounts of monomers.
  • the propellant is normally a liquid having a boiling temperature not higher than the softening temperature of the thermoplastic polymer shell and may comprise hydrocarbons such as propane, n-pentane, isopentane, neopentane, butane, isobutane, hexane, isohexane, neohexane, heptane, isoheptane, octane or isooctane, or mixtures thereof.
  • hydrocarbon types can also be used, such as petroleum ether, or chlorinated or fluorinated hydrocarbons, such as methyl chloride, methylene chloride, dichloroethane, dichloroethylene, trichloroethane, trichloroethylene, trichlorofluoromethane, perfluorinated hydrocarbons, etc.
  • Preferred propellants comprise isobutane, alone or in a mixture with one or more other hydrocarbons.
  • the boiling point at atmospheric pressure is preferably within the range from about -50 to about 100 °C, most preferably from about -20 to about 50 °C, particularly most preferably from about -20 to about 30 °C.
  • the microspheres may comprise further substances added during the production thereof, normally in an amount from about 1 to about 20 wt%, preferably from about 2 to about 10 wt%.
  • Such substances are solid suspending agents, such as one or more of silica, chalk, bentonite, starch, crosslinked polymers, methyl cellulose, gum agar, hydroxypropyl methylcellulose, carboxy methylcellulose, colloidal clays, and/or one or more salts, oxides or hydroxides of metals like Al, Ca, Mg, Ba, Fe, Zn, Ni and Mn, for example one or more of calcium phosphate, calcium carbonate, magnesium hydroxide, barium sulphate, calcium oxalate, and hydroxides of aluminium, iron, zinc, nickel or manganese.
  • solid suspending agents such as one or more of silica, chalk, bentonite, starch, crosslinked polymers, methyl cellulose, gum agar, hydroxypropyl methylcellulose, carboxy methylcellulose, coll
  • these solid suspending agents are normally mainly located to the outer surface of the polymer shell. However, even if a suspending agent has been added during the production of the microspheres, this may have been washed off at, a later stage and could thus be substantially absent from the final product.
  • thermoplastic polymer shell made of a co-polymer obtained by polymerising ethylenically unsaturated monomers comprising at least one acrylic ester or methacrylic ester monomer and at least one vinylidene halide monomer, and from about 17 to about 40 wt%, preferably from about 18 to about 40 wt%, most preferably from about 19 to about 40 wt%, particularly most preferably from about 20 to about 35 wt% of a propellant entrapped in said polymer shell, wherein the expandable microspheres have a volume-average diameter from about 17 to about 35 ⁇ m, preferably from about 18 to about 35 ⁇ m, more preferably from about 19 to about 35 ⁇ m, most preferably from about 20 to about 30 ⁇ m, particularly most preferably from about 21 to about 30 ⁇ m.
  • novel expandable microspheres can be prepared by polymerising the monomers in the presence of the propellant with the same methods as described in the earlier mentioned US Patents 3615972, 3945956, 5536756, 6235800, 6235394 and 6509384, and in EP 486080.
  • the polymerisation is conducted as described below in a reaction vessel.
  • one or more polymerisation initiator preferably in an amount from about 0.1 to about 5 parts
  • aqueous phase preferably in an amount from about 100 to about 800 parts
  • one or more preferably solid colloidal suspending agent preferably in an amount from about 1 to about 20 parts
  • the temperature is suitably maintained from about 40 to about 90°C, preferably from about 50 to about 80°C, while the suitable pH depends on the suspending agent used.
  • a high pH preferably from about 6 to about 12, most preferably from about 8 to about 10, is suitable if the suspending agent is selected from salts, oxides or hydroxides of metals like Al, Ca, Mg, Ba, Fe, Zn, Ni and
  • Mn for example one or more of calcium phosphate, calcium carbonate, chalk, magnesium hydroxide, barium sulphate, calcium oxalate, and hydroxides of aluminium, iron, zinc, nickel or manganese.
  • a low pH preferably from about 1 to about 6, most preferably from about 3 to about 5, is suitable if the suspending agent is selected from silica, bentonite, starch, methyl cellulose, gum agar, hydroxypropyl methylcellulose, carboxy methylcellulose, colloidal clays.
  • Each one of the above agents have different optimal pH, depending on, for example, solubility data.
  • promoters are organic materials and may, for example, be selected from one or more of water-soluble sulfonated polystyrenes, alginates, carboxymethylcellulose, tetramethyl ammonium hydroxide or chloride or water-soluble complex resinous amine condensation products such as the water-soluble condensation products of diethanolamine and adipic acid, the water-soluble condensation products of ethylene oxide, urea and formaldehyde, polyethylenimine, polyvinylalcohol, polyvinylpyrrolidone, amphoteric materials such as proteinaceous, materials like gelatin, glue, casein, albumin, glutin and the like, non-ionic materials like methoxycellulose, ionic materials normally classed as emulsifiers, such as soaps, alkyl sulfates and sul
  • initiators are suitably selected from one or more of organic peroxides such as dialkyl peroxides, diacyl peroxides, peroxy esters, peroxy dicarbonates, or azo compounds.
  • Suitable initiators include dicetyl peroxy dicarbonate, tert-butyl cyclohexyl peroxy dicarbonate, dioctanoyl peroxide, dibenzoyl peroxide, dilauroyl peroxide, didecanoyl peroxide, tert-butyl peracetate, tert-butyl perlaurate, tert-butyl perbenzoate, tert-butyl hydroperoxide, cumene hydroperoxide, cumene ethylperoxide, diisopropyl hydroxy dicarboxylate, azo-bis dimethyl valeronitrile, azo-bis isobutyronitrile, azo-bis (cyclo hexyl carbonit
  • microspheres are normally obtained as an aqueous slurry or dispersion, which can be dewatered by any conventional means, such as bed filtering, filter pressing, leaf filtering, rotary filtering, belt filtering or centrifuging to obtain a so called wet cake that can be used as such.
  • any conventional means such as bed filtering, filter pressing, leaf filtering, rotary filtering, belt filtering or centrifuging to obtain a so called wet cake that can be used as such.
  • it is also possible to dry the microspheres by any conventional means, such as spray drying, shelf drying, tunnel drying, rotary drying, drum drying, pneumatic drying, turbo shelf drying, disc drying or fluidised bed-drying.
  • EXAMPLE 1 A three layer paper board with a basis weight of about 180 g/m 2 was produced in a pilot paper machine with a machine speed of 7 m/min and having recirculated process water.
  • the pulp was composed of 40 wt% hardwood and 60 wt% softwood pulp and was beaten to a Schopper-Riegler value of 25°SR and then dispersed to give a pulp slurry/stock.
  • An aqueous slurry of expandable microspheres was before the mixing pump added to the stock used for the middle layer in an amount of about 1 wt% dry microspheres of the dry substance in the stock.
  • As retention aid 0.1 wt% PolyminTM SK was used.
  • EXAMPLE 2 A single layer paper board with a basis weight of about 200 g/m 2 was produced in a pilot paper machine with a machine speed of 4 m/min and not having recirculated process water.
  • the pulp was composed of 50 wt% hardwood and 50 wt% softwood pulp and was beaten to a Schopper-Riegler value of 25°SR and then dispersed to give a pulp slurry/stock.
  • An aqueous slurry of expandable microspheres was before the mixing pump added to the stock in an amount of about 1.75 wt% dry microspheres of the dry substance in the stock.
  • As retention aid Compozil ® 0.1% BMA-OTM and 0.75% RaisamylTM 135, was used.

Abstract

The invention relates to a process for the production of paper or nonwoven from fibres comprising the steps of adding thermally expandable microspheres comprising a thermoplastic polymer shell and a propellant entrapped therein to a stock comprising fibres or to a web of fibres, forming paper or nonwoven from the stock or the web, and applying heat to raise the temperature of the microspheres sufficiently for them to expand and thereby increase the bulk of the paper or the nonwoven, wherein said expandable microspheres comprise from about 17 to about 40 wt% propellant and have a volume-average diameter from about 17 to about 35 µm.The invention also concerns certain expandable microspheres and use thereof.

Description

MICROSPHERES
The present invention relates to a process for the production of paper or nonwoven and thermoplastic expandable microspheres useful therefore.
Expandable thermoplastic microspheres comprising a thermoplastic polymer shell and a propellant entrapped therein are commercially available under the trademark EXPANCEL® and are used as a foaming agent in many different applications.
In such microspheres, the propellant is normally a liquid having a boiling temperature not higher than the softening temperature of the thermoplastic polymer shell. Upon heating, the propellant evaporates to increase the internal pressure at the same time as the shell softens, resulting in significant expansion of the microspheres. The temperature at which the expansion starts is called Tstart> while the temperature at which maximum expansion is reached is called Tmaχ. Expandable microspheres are marketed in various forms, e.g. as dry free flowing particles, as an aqueous slurry or as a partially dewatered wet-cake. Expandable microspheres can be produced by polymerising ethylenically unsaturated monomers in the presence of a propellant. Detailed descriptions of various expandable microspheres and their production can be found in, for example, US Patents 3615972, 3945956, 5536756, 6235800, 6235394 and 6509384, and in EP 486080.
It has been disclosed to use microspheres in papermaking, for example in US Patents 3556934 and 4133688, JP Patent 2689787 and in O. Soderberg, "World Pulp & Paper Technology 1995/96, The International Review for the Pulp & Paper Industry" p. 143-145.
It is an object of the invention to provide a process for the production of paper or nonwoven with low bulk density. It is another object of the invention to provide expandable thermoplastic microspheres that can be used in the production of paper or nonwoven with low bulk density.
It has previously been believed that expandable thermoplastic microspheres of large size would have poor expansion properties. However, it has now been found that such microspheres, when also having high content of propellant, give higher expansion than expected when used in the production of paper or nonwoven for increasing the bulk thereof.
The invention thus concerns use of thermally expandable microspheres comprising a thermoplastic polymer shell and from about 17 to about 40 wt%, preferably from about 18 to about 40 wt%, most preferably from about 19 to about 40 wt%, particularly most preferably from about 20 to about 35 wt% of a propellant entrapped in said polymer shell, and having a volume-average diameter from about 17 to about 35 μm, preferably from about 18 to about 35 μm, more preferably from about 19 to about 35 μm, most preferably from about 20 to about 30 μm, particularly most preferably from about 21 to about 30 μm, in the production of paper or non-woven for increasing the bulk thereof. The term expandable microspheres as used herein refers to expandable microspheres that have not previously been expanded, i.e. unexpanded expandable microspheres.
All figures for volume-average diameter given herein refer to values obtained by measuring according to ISO 13319:2000, "Determination of particle size distributions - Electrical sensing zone method". Detailed description of this measuring method can be obtained from, for example, Swedish Institute For Standards, Stockholm.
The invention further concerns a process for the production of paper or nonwoven from fibres comprising the steps of adding thermally expandable microspheres comprising a thermoplastic polymer shell and a propellant entrapped therein to a stock comprising fibres or to a web of fibres, forming paper or nonwoven from the stock or the web, and applying heat to raise the temperature of the microspheres sufficiently for them to expand and thereby increase the bulk of the paper or the nonwoven. The expandable microspheres have a volume-average diameter from about 17 to about 35 μm, preferably from about 18 to about 35 μm, more preferably from about 19 to about 35 μm, most preferably from about 20 to about 30 μm, particularly most preferably from about 21 to about 30 μm. The amount of propellant in the expandable microspheres is from about 17 to about 40 wt%, preferably from about 18 to about 40 wt%, most preferably from about 19 to about 40 wt%, particularly most preferably from about 20 to about 35 wt%.
An embodiment of the invention concerns a process for the production of paper comprising the steps of adding expandable microspheres as described above to a stock containing cellulosic fibres, dewatering the stock on a wire to obtain paper, and drying the paper by applying heat and thereby also raising the temperature of the microspheres sufficiently for them to expand and increase the bulk of the paper. The expandable microspheres may be added separately or together with one or more other additive used in the papermaking process. The expandable microspheres can be added in any form, although it from a practical point of view is most preferred to add them in the form of an aqueous slurry, preferably having a solids content from about 5 to about 55 wt %, most preferably from about 40 to about 50 wt%. The slurry preferably also comprises a thickener compatible with paper making, such as anionic or cationic starch, optionally in combination with a salt such as sodium chloride. Starch may, for example, be present in the slurry in an amount from about 0.1 to about 5 wt%, preferably from about 0.3 to about 1.5 wt%. Sodium chloride, or another salt, may, for example, be present in the slurry in an amount from about 0.1 to about 20 wt%, preferably from about 1 to about 15 wt%.
The amount of expandable microspheres added to the stock is preferably from about 0.1 to about 20 wt%, most preferably from about 0.2 to about 10 wt% dry microspheres of the dry content in the stock. Any kind of paper machine known in the art can be used.
The term "paper", as used herein, is meant to include all types of cellulose-based products in sheet or web form, including, for example, board, cardboard and paperboard.
The invention has been found particularly advantageous for the production of board, cardboard and paper board, particularly with a basis weight from about 50 to about 1000 g/m2, preferably from about 150 to about 800 g/m2.
The paper may be produced as a single layer or a multi-layer paper. If the paper comprises three or more layers, the expandable microspheres are preferably not added to the portion of the stock forming any of the two outer layers. The stock preferably contains from about 50 to about 100 wt%, most preferably from about 70 to about 100 wt% of cellulosic fibres, based on dry material. Before dewatering, the stock besides expandable microspheres, may also contain one or more fillers, e.g. mineral fillers like kaolin, china clay, titanium dioxide, gypsum, talc, chalk, ground marble or precipitated calcium carbonate, and optionally other commonly used additives, such as retention aids, sizing agents, aluminium compounds, dyes, wet-strength resins, optical brightening agents, etc. Examples of aluminium compounds include alum, alumina- tes and polyaluminium compounds, e.g. polyaluminium chlorides and sulphates. Examples of retention aids include cationic polymers, anionic inorganic materials in combination with organic polymers, e.g. bentonite in combination with cationic polymers or silica-based sols in combination with cationic polymers or cationic and anionic polymers. Examples of sizing agents include cellulose reactive sizes such as alkyl ketene dimers and alkenyl succinic anhydride, and cellulose non-reactive sizes such as rosin, starch and other polymeric sizes like copolymers of styrene with vinyl monomers such as maleic anhydride, acrylic acid and its alkyl esters, acrylamide, etc. At drying, the paper, and thereby also the microspheres, is preferably heated to a temperature from about 50 to about 150°C, most preferably from about 60 to about 110°C. This results in expansion of the microspheres and thereby also a bulk increase of the paper. The magnitude of this bulk increase depends on various factors, such as the origin of cellulosic fibres and other components in the stock, but is in most cases from about 5 to about 50 % per weight percentage of retained microspheres in the dried paper, compared to the same kind of paper produced without addition of expandable microspheres or any other expansion agent. Any conventional means of drying involving transferring heat to the paper can be applied, such as contact drying (e.g. by heated cylinders), forced convection drying (e.g. by hot air), infrared techniques, or combinations thereof. In the case of contact drying, the temperature of the contact surfaces, e.g. the cylinders, is preferably from about 20 to about 150°C, most preferably from about 30 to about 130°C. The paper may pass a series of several cylinders, e.g. up to 20 or more, of increasing temperature.
The cellulosic fibres in the stock may, for example, come from pulp made from any kind of plants, preferably wood, such as hardwood and softwood. The cellulosic fibres may also partly or fully originate from recycled paper, in which case the invention has been found to give unexpectedly good results.
Another embodiment of the invention concerns a process for the production of nonwoven comprising the steps of forming a web of fibres, adding to said web a binder and expandable microspheres as described above, and forming nonwoven and applying heat to raise the temperature of the microspheres sufficiently for them to expand and thereby increase the bulk nonwoven. The expandable microspheres and the binder may be added separately or as a mixture. The amount of expandable microspheres added is preferably from about 0.1 to about 30 wt% of dried product, most preferably from about 0.5 to about 15 wt% of dried product. The amount of binder added is preferably from about 10 to about 90 wt% of dried product, most preferably from about 20 to about 80 wt% of dried product. The term "nonwoven" as used herein is meant to include textiles made from fibres bonded together by means of a binder.
The web of fibres can be formed in any conventional way, for example by mechanical or aerodynamical dry methods, hydrodynamical (wet) methods, or spunbonded processes. The binder, preferably pre-mixed with expandable microspheres, can then be added to the web also in any conventional way, for example by any kind of impregnation method such as immersion of the web in a bath of binder or coating the web by kiss roll application or knife coating with a doctor blade or floating knife.
The web comprising a binder and expandable microspheres can then be heated to a temperature sufficient for the microspheres to expand, preferably from about 70 to about 200°C, most preferably from about 120 to about 160°C. Preferably, curing of the binder takes place at the same time. The heating can be effected by any suitable means, such as contact drying (e.g. by heated cylinders), forced convection drying (e.g. by hot air), infrared techniques, or combinations thereof.
The fibres can be any kind of commercially available fibres, natural fibres, mineral fibres, as well as synthetic inorganic and organic fibres. Examples of useful fibres include polypropylene, polyethylene, polyester, viscose, and polyamide fibres, as well as fibres made from two or more of the above polymers. The binder can be any kind of natural or synthetic adhesive resin, such as resins of polyacrylates and co-polymers thereof, polymethacrylates and co-polymers thereof, rubber latexes such as styrene/butadiene copolymers, acrylonitrile/butadiene copolymers, poly(vinyl chloride) and copolymers, poly(vinyl ester) such as poly(vinyl acetate) and co- polymers, e.g. with ethylene, poly(vinyl alcohol), polyurethane, and aminoplast and phenoplast precondensates such as urea/ formaldehyde, urea/ melamine / formaldehyde or phenol/ formaldehyde.
Preferred expandable microspheres to be used according to the invention are described below. The thermoplastic polymer shell of the expandable microspheres is suitably made of a homo- or co-polymer obtained by polymerising ethylenically unsaturated monomers. Those monomers can, for example, be nitrile containing monomers such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, -ethoxyacrylonitrile, fumaronitrile or crotonitrile; acrylic esters such as methyl acrylate or ethyl acrylate; methacrylic esters such as methyl methacrylate, isobornyl methacrylate or ethyl methacrylate; vinyl halides such as vinyl chloride; vinyl esters such as vinyl acetate other vinyl monomers such as vinyl pyridine; vinylidene halides such as vinylidene chloride; styrenes such as styrene, halogenated styrenes or α-methyl styrene; or dienes such as butadiene, isoprene and chloroprene. Any mixtures of the above mentioned monomers may also be used. Preferably the monomers comprise at least one acrylic ester or methacrylic ester monomer, most preferably methacrylic ester monomer such as methyl methacrylate. The amount thereof in the polymer shell is preferably from about 0.1 to about 80 wt%, most preferably from about 1 to about 25 wt% of the total amounts of monomers.
Preferably the monomers comprise at least one vinylidene halide monomer, most preferably vinylidene chloride. The amount thereof in the polymer shell is preferably from about 1 to about 90 wt%, most preferably from about 20 to about 80 wt% of the total amounts of monomers.
Most preferably the monomers comprise both at least one acrylic ester or methacrylic ester monomer and at least one vinylidene halide monomer. Preferably the monomers comprise at least one nitrile containing monomer, most preferably at least one of acrylonitrile and methacrylonitrile, particularly most preferably at least acrylonitrile. The amount thereof in the polymer shell is preferably from about 1 to about 80 wt%, most preferably from about 20 wt% to about 70 wt% of the total amounts of monomers. In an advantageous embodiment the monomers comprise at least one acrylic ester monomer, at least one vinylidene halide and at least one nitrile containing monomer. The polymer shell may then, for example, be a co-polymer obtained from monomers comprising methyl methacrylate in a preferred amount from about 0.1 to about
80 wt%, most preferably from about 1 to about 25 wt% of the total amounts of monomers, vinylidene chloride in a preferred amount from about 1 to about 90 wt%, most preferably from about 20 to about 80 wt% of the total amounts of monomers, and acrylonitrile in a preferred amount from about 1 to about 80 wt%, most preferably from about 20 to about
70 wt% of the total amounts of monomers.
It may sometimes be desirable that the monomers for the polymer shell also comprise crosslinking multifunctional monomers, such as at least one of divinyl benzene, ethylene glycol di(meth)acrylate, di(ethylene glycol) di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1 ,4-butanediol di(meth)acrylate, 1 ,6- hexanediol di(meth)acrylate, glycerol di(meth)acrylate, 1 ,3-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1 ,10-decanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, triallylformal tri(meth)acrylate, allyl methacrylate, trimethylol propane tri(meth)acrylate, tributanediol di(meth)acrylate, PEG #200 di(meth)acrylate, PEG #400 di(meth)acrylate, PEG #600 di(meth)acrylate, 3- acryloyloxyglycol monoacrylate, triacryl formal or triallyl isocyanate, triallyl isocyanurate etc. The amount thereof in the polymer shell is preferably from about 0.1 to about 10 wt%, most preferably from about 0.1 to about 1 wt%, particularly most preferably from about 0.2 to about 0.5 wt% of the total amounts of monomers. The propellant is normally a liquid having a boiling temperature not higher than the softening temperature of the thermoplastic polymer shell and may comprise hydrocarbons such as propane, n-pentane, isopentane, neopentane, butane, isobutane, hexane, isohexane, neohexane, heptane, isoheptane, octane or isooctane, or mixtures thereof. Aside from them, other hydrocarbon types can also be used, such as petroleum ether, or chlorinated or fluorinated hydrocarbons, such as methyl chloride, methylene chloride, dichloroethane, dichloroethylene, trichloroethane, trichloroethylene, trichlorofluoromethane, perfluorinated hydrocarbons, etc. Preferred propellants comprise isobutane, alone or in a mixture with one or more other hydrocarbons. The boiling point at atmospheric pressure is preferably within the range from about -50 to about 100 °C, most preferably from about -20 to about 50 °C, particularly most preferably from about -20 to about 30 °C.
Apart from the polymer shell and the propellant the microspheres may comprise further substances added during the production thereof, normally in an amount from about 1 to about 20 wt%, preferably from about 2 to about 10 wt%. Examples of such substances are solid suspending agents, such as one or more of silica, chalk, bentonite, starch, crosslinked polymers, methyl cellulose, gum agar, hydroxypropyl methylcellulose, carboxy methylcellulose, colloidal clays, and/or one or more salts, oxides or hydroxides of metals like Al, Ca, Mg, Ba, Fe, Zn, Ni and Mn, for example one or more of calcium phosphate, calcium carbonate, magnesium hydroxide, barium sulphate, calcium oxalate, and hydroxides of aluminium, iron, zinc, nickel or manganese. If present, these solid suspending agents are normally mainly located to the outer surface of the polymer shell. However, even if a suspending agent has been added during the production of the microspheres, this may have been washed off at, a later stage and could thus be substantially absent from the final product.
Some of the microspheres described above are novel. The invention thus also concerns thermally expandable microspheres comprising a thermoplastic polymer shell made of a co-polymer obtained by polymerising ethylenically unsaturated monomers comprising at least one acrylic ester or methacrylic ester monomer and at least one vinylidene halide monomer, and from about 17 to about 40 wt%, preferably from about 18 to about 40 wt%, most preferably from about 19 to about 40 wt%, particularly most preferably from about 20 to about 35 wt% of a propellant entrapped in said polymer shell, wherein the expandable microspheres have a volume-average diameter from about 17 to about 35 μm, preferably from about 18 to about 35 μm, more preferably from about 19 to about 35 μm, most preferably from about 20 to about 30 μm, particularly most preferably from about 21 to about 30 μm. Regarding further possible and preferred embodiments of the novel microspheres, applicable parts of the above description of the process for the production of paper or nonwoven is referred to.
The novel expandable microspheres can be prepared by polymerising the monomers in the presence of the propellant with the same methods as described in the earlier mentioned US Patents 3615972, 3945956, 5536756, 6235800, 6235394 and 6509384, and in EP 486080. In a preferred batchwise procedure for producing expandable microspheres, the polymerisation is conducted as described below in a reaction vessel. For 100 parts of monomer phase (suitably including monomers and propellant, the ratio of which determines the amount of propellant in the final product), one or more polymerisation initiator, preferably in an amount from about 0.1 to about 5 parts, aqueous phase, preferably in an amount from about 100 to about 800 parts, and one or more preferably solid colloidal suspending agent, preferably in an amount from about 1 to about 20 parts, are mixed and homogenised. The size of the droplets of monomer phase obtained determines the size of the final expandable microspheres, in accordance with principles described in e.g. US Patent 3615972 and can be applied for all similar production methods with various suspending agents. The temperature is suitably maintained from about 40 to about 90°C, preferably from about 50 to about 80°C, while the suitable pH depends on the suspending agent used. For example, a high pH, preferably from about 6 to about 12, most preferably from about 8 to about 10, is suitable if the suspending agent is selected from salts, oxides or hydroxides of metals like Al, Ca, Mg, Ba, Fe, Zn, Ni and
Mn, for example one or more of calcium phosphate, calcium carbonate, chalk, magnesium hydroxide, barium sulphate, calcium oxalate, and hydroxides of aluminium, iron, zinc, nickel or manganese. A low pH, preferably from about 1 to about 6, most preferably from about 3 to about 5, is suitable if the suspending agent is selected from silica, bentonite, starch, methyl cellulose, gum agar, hydroxypropyl methylcellulose, carboxy methylcellulose, colloidal clays. Each one of the above agents have different optimal pH, depending on, for example, solubility data. In order to enhance the effect of the suspending agent, it is also possible to add small amounts of one or more promoters, for example from about 0.001 to about 1 wt%. Usually, such promoters are organic materials and may, for example, be selected from one or more of water-soluble sulfonated polystyrenes, alginates, carboxymethylcellulose, tetramethyl ammonium hydroxide or chloride or water-soluble complex resinous amine condensation products such as the water-soluble condensation products of diethanolamine and adipic acid, the water-soluble condensation products of ethylene oxide, urea and formaldehyde, polyethylenimine, polyvinylalcohol, polyvinylpyrrolidone, amphoteric materials such as proteinaceous, materials like gelatin, glue, casein, albumin, glutin and the like, non-ionic materials like methoxycellulose, ionic materials normally classed as emulsifiers, such as soaps, alkyl sulfates and sulfonates and long chain quaternary ammonium compounds.
Conventional radical polymerisation may be used and initiators are suitably selected from one or more of organic peroxides such as dialkyl peroxides, diacyl peroxides, peroxy esters, peroxy dicarbonates, or azo compounds. Suitable initiators include dicetyl peroxy dicarbonate, tert-butyl cyclohexyl peroxy dicarbonate, dioctanoyl peroxide, dibenzoyl peroxide, dilauroyl peroxide, didecanoyl peroxide, tert-butyl peracetate, tert-butyl perlaurate, tert-butyl perbenzoate, tert-butyl hydroperoxide, cumene hydroperoxide, cumene ethylperoxide, diisopropyl hydroxy dicarboxylate, azo-bis dimethyl valeronitrile, azo-bis isobutyronitrile, azo-bis (cyclo hexyl carbonitrile) and the like. It is also possible to initiate the polymerisation with radiation, such as high energy ionising radiation.
When the polymerisation is essentially complete, microspheres are normally obtained as an aqueous slurry or dispersion, which can be dewatered by any conventional means, such as bed filtering, filter pressing, leaf filtering, rotary filtering, belt filtering or centrifuging to obtain a so called wet cake that can be used as such. However, it is also possible to dry the microspheres by any conventional means, such as spray drying, shelf drying, tunnel drying, rotary drying, drum drying, pneumatic drying, turbo shelf drying, disc drying or fluidised bed-drying.
The invention will now be further described in connections with the following Examples, which, however, not should be interpreted as limiting the scope thereof. If not otherwise stated, all parts and percentages refer to parts and percent by weight.
EXAMPLE 1 : A three layer paper board with a basis weight of about 180 g/m2 was produced in a pilot paper machine with a machine speed of 7 m/min and having recirculated process water. The pulp was composed of 40 wt% hardwood and 60 wt% softwood pulp and was beaten to a Schopper-Riegler value of 25°SR and then dispersed to give a pulp slurry/stock. An aqueous slurry of expandable microspheres was before the mixing pump added to the stock used for the middle layer in an amount of about 1 wt% dry microspheres of the dry substance in the stock. As retention aid 0.1 wt% Polymin™ SK was used. In the drying section the paper web was heated by cylinders having a temperature profile from 30 to 130°C. Different kinds of expandable microspheres were tested, all having isobutane as propellant and a polymer shell from vinylidene chloride (VDC), acrylonitrile (ACN) and methyl methacrylate (MMA) but in various ratios. In order to determine the retention of the microspheres, paper samples were taken before the press section for determination of the amount of microspheres (using GC). The retention was calculated from the microspheres addition and the content of microspheres in the paper. Moreover, samples from the dried paper were taken for determination of bulk and thickness . The results are shown in Table 1. Table 1
EXAMPLE 2: A single layer paper board with a basis weight of about 200 g/m2 was produced in a pilot paper machine with a machine speed of 4 m/min and not having recirculated process water. The pulp was composed of 50 wt% hardwood and 50 wt% softwood pulp and was beaten to a Schopper-Riegler value of 25°SR and then dispersed to give a pulp slurry/stock. An aqueous slurry of expandable microspheres was before the mixing pump added to the stock in an amount of about 1.75 wt% dry microspheres of the dry substance in the stock. As retention aid Compozil®, 0.1% BMA-O™ and 0.75% Raisamyl™ 135, was used. In the drying section the paper web was heated by cylinders having a temperature profile from 65 to 122°C. Expandable microspheres with the same propellant and same monomers in the polymer shell as in Exampel 1 were tested. The retention of microspheres and the bulk/thickness of the paper were determined as in Example 1. The results are shown in Table 1 Table 2
It appears that the overall trend is that the combination of high amount of propellant and large particle diameter gives high increase of the bulk of the paper. However, due to difficulties to exactly measure the amount of retained microspheres, some individual results may be inconsistent with the overall trend.

Claims

1. Process for the production of paper or nonwoven from fibres comprising the steps of adding thermally expandable microspheres comprising a thermoplastic polymer shell and a propellant entrapped therein to a stock comprising fibres or to a web of fibres, forming paper or nonwoven from the stock or the web, and applying heat to raise the temperature of the microspheres sufficiently for them to expand and thereby increase the bulk of the paper or the nonwoven, wherein said expandable microspheres comprise from about 17 to about 40 wt% propellant and have a volume-average diameter from about 17 to about 35 μm according to IS013319:2000.
2. Process as claimed in claim 1 , wherein the expandable microspheres have a volume-average diameter from about 19 to about 35 μm according to IS013319:2000.
3. Process as claimed in claim 1 , wherein the expandable microspheres comprise from about 19 to about 40 wt% propellant.
4. Process as claimed in any one of claims 1-3, wherein the thermoplastic polymer shell is made of a co-polymer from ethylenically unsaturated monomers comprising at least one acrylic ester or methacrylic ester monomer and at least one vinylidene halide monomer.
5. Process as claimed in claim 4, wherein the thermoplastic polymer shell is a co-polymer obtained from monomers comprising methyl methacrylate, vinylidene chloride and acrylo nitrile.
6. Process as claimed in any one of claims 1-5, wherein the propellant comprise isobutane.
7. Process for the production of paper as claimed in any one of the claims 1-6 comprising the steps of adding expandable microspheres as defined in any one of the claims 1-5 to a stock containing cellulosic fibres, dewatering the stock on a wire to obtain paper, and drying the paper by applying heat and thereby also raising the temperature of the microspheres sufficiently for them to expand and increase the bulk of the paper.
8. Process as claimed in claim 7, wherein paper comprising three or more layers is produced and the expandable microspheres are not added to the portion of the stock forming any of the two outer layers.
9. Process as claimed in any one of claims 7-8, wherein the cellulosic fibres partly or fully originate from recycled paper.
10. Process for the production of non-woven as claimed in any one of the claims
1-6 comprising the steps of forming a web of fibres, adding to said web a binder and expandable microspheres as defined in any one of the claims 1-5, and forming nonwoven and applying heat to raise the temperature of the microspheres sufficiently for them to expand and thereby increase the bulk nonwoven.
11. Use of thermally expandable microspheres comprising a thermoplastic polymer shell and from about 17 to about 40 wt% of a propellant entrapped in said polymer shell, and having a volume-average diameter from about 17 to about 35 μm according to IS013319:2000, in the production of paper or non-woven for increasing the bulk thereof.
12. Thermally expandable microspheres comprising a thermoplastic polymer shell made of a co-polymer obtained by polymerising ethylenically unsaturated monomers comprising at least one acrylic ester or methacrylic ester monomer and at least one vinylidene halide monomer, and from about 17 to about 40 wt% of a propellant entrapped in said polymer shell, wherein the expandable microspheres have a volume-average diameter from about 17 to about 35 μm according to ISO13319:2000.
13. Thermally expandable microspheres as claimed in claim 12, wherein the ethylenically unsaturated monomers comprise acrylo nitrile.
14. Thermally expandable microspheres as claimed in any one of claims 12-13 having a volume-average diameter from about 19 to about 35 μm according to
ISO13319:2000.
15. Thermally expandable microspheres as claimed in any one of claims 12-14 comprising from about 19 to about 40 wt% propellant.
16. Thermally expandable microspheres as claimed in any one of claims 12-15, wherein the blowing agent comprises isobutane.
EP04735699A 2003-06-26 2004-06-01 Microspheres Withdrawn EP1636422A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP04735699A EP1636422A1 (en) 2003-06-26 2004-06-01 Microspheres

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US48249703P 2003-06-26 2003-06-26
EP03445085 2003-06-26
EP04735699A EP1636422A1 (en) 2003-06-26 2004-06-01 Microspheres
PCT/SE2004/000835 WO2004113613A1 (en) 2003-06-26 2004-06-01 Microspheres

Publications (1)

Publication Number Publication Date
EP1636422A1 true EP1636422A1 (en) 2006-03-22

Family

ID=33542576

Family Applications (1)

Application Number Title Priority Date Filing Date
EP04735699A Withdrawn EP1636422A1 (en) 2003-06-26 2004-06-01 Microspheres

Country Status (8)

Country Link
US (1) US20060102307A1 (en)
EP (1) EP1636422A1 (en)
JP (1) JP2007521410A (en)
KR (1) KR100826419B1 (en)
CN (1) CN1813105A (en)
CA (1) CA2529139A1 (en)
NO (1) NO20060372L (en)
WO (1) WO2004113613A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2295390A1 (en) 2009-09-04 2011-03-16 Manfred Jaeckel Method for producing a cellular sinter mould

Families Citing this family (39)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6866906B2 (en) 2000-01-26 2005-03-15 International Paper Company Cut resistant paper and paper articles and method for making same
RU2330911C2 (en) 2002-09-13 2008-08-10 Интернэшнл Пейпер Компани Paper of improved rigidity and bulk and method to produce thereof
CN1795307B (en) * 2003-04-07 2010-09-08 国际纸业公司 Papers for liquid electrophotographic printing and method for making same
US7361399B2 (en) * 2004-05-24 2008-04-22 International Paper Company Gloss coated multifunctional printing paper
CA2591874C (en) * 2004-12-22 2012-01-31 Akzo Nobel N.V. Microsphere and thickener containing composition and its use in the production of paper
CN101137790A (en) * 2005-03-11 2008-03-05 国际纸业公司 Compositions containing expandable microspheres and an ionic compound, as well as methods of making and using the same
CN101449002B (en) 2006-01-17 2012-02-15 国际纸业公司 Paper substrates containing high surface sizing and low internal sizing and having high dimensional stability
US7956096B2 (en) 2006-02-10 2011-06-07 Akzo Nobel N.V. Microspheres
UA92207C2 (en) * 2006-02-10 2010-10-11 Акцо Нобель Н.В. thermally expandable thermoplastic microspheres, method of producing thereof, use, water suspension containing thereof, and method for producing paper
US8388809B2 (en) 2006-02-10 2013-03-05 Akzo Nobel N.V. Microspheres
EP1981630B1 (en) 2006-02-10 2015-09-23 Akzo Nobel N.V. Microspheres
US20130303351A1 (en) 2006-04-03 2013-11-14 Lbp Manufacturing, Inc. Microwave heating of heat-expandable materials for making packaging substrates and products
PT2243719E (en) 2006-04-03 2013-01-07 Lbp Mfg Inc Thermally activatable insulating packaging
US9522772B2 (en) 2006-04-03 2016-12-20 Lbp Manufacturing Llc Insulating packaging
US9648969B2 (en) 2006-04-03 2017-05-16 Lbp Manufacturing Llc Insulating packaging
UA94460C2 (en) * 2006-06-08 2011-05-10 Акцо Нобель Н.В. Thermally expandable thermoplastic microspheres, producing method, use, water suspension containing thereof and method for producing paper
US7829162B2 (en) 2006-08-29 2010-11-09 international imagining materials, inc Thermal transfer ribbon
CN101529020A (en) * 2006-10-31 2009-09-09 巴斯夫欧洲公司 Method for producing a multi layer fiber web from cellulose fibers
WO2008066488A1 (en) * 2006-12-01 2008-06-05 Akzo Nobel N.V. Cellulosic product
PT3000933T (en) 2008-03-31 2018-10-25 Int Paper Co Recording sheet with enhanced print quality at low additive levels
RU2011101414A (en) 2008-06-17 2012-07-27 Акцо Нобель Н.В. (NL) CELLULAR PRODUCT
EP2787120A1 (en) 2008-06-20 2014-10-08 International Paper Company Recording sheet with improved optical properties
WO2010025383A1 (en) 2008-08-28 2010-03-04 International Paper Company Expandable microspheres and methods of making and using the same
US9296244B2 (en) 2008-09-26 2016-03-29 International Paper Company Composition suitable for multifunctional printing and recording sheet containing same
JP5202284B2 (en) * 2008-12-22 2013-06-05 株式会社日立産機システム Thermosetting resin composition
CA2808464C (en) 2010-09-01 2016-07-19 Lbp Manufacturing, Inc. Process of expediting activation of heat-expandable adhesives/coatings used in making packaging substrates
US9206552B2 (en) 2012-02-17 2015-12-08 International Paper Company Absorbent plastic pigment with improved print density containing and recording sheet containing same
WO2013132017A1 (en) * 2012-03-09 2013-09-12 Philip Morris Products S.A. Layered sheetlike material comprising cellulose fibres
FI124235B (en) * 2012-04-26 2014-05-15 Stora Enso Oyj Fiber-based paper or paperboard web and a process for its manufacture
FI124556B (en) 2012-04-26 2014-10-15 Stora Enso Oyj Hydrophobic-bonded fiber web and process for manufacturing a bonded web layer
US20150147507A1 (en) 2012-04-27 2015-05-28 Sa Des Eaux Minerales D'evian Saeme Article comprising foamed polylactic acid and process of making the same
US8679296B2 (en) 2012-07-31 2014-03-25 Kimberly-Clark Worldwide, Inc. High bulk tissue comprising expandable microspheres
US9624408B2 (en) 2013-03-28 2017-04-18 Basf Se Method for coagulating polymer dispersions using expandable microspheres
RU2640531C2 (en) 2013-06-12 2018-01-09 Сикпа Холдинг Са Thermo-sensitive tags for detecting adulteration
CA2963165C (en) 2014-10-01 2023-05-16 Jowat Se Aqueous coagulatable polymer dispersion and use thereof as an adhesive
CN106835785B (en) * 2016-12-19 2019-03-22 西能化工科技(上海)有限公司 The preparation method of paper pulp comprising expandable microspheres and its purposes in speciality paper
CN111851139B (en) * 2019-04-30 2022-08-12 陆筱棣 Method for preparing expandable microspheres, microspheres obtained by method and application of microspheres
CN112064194A (en) * 2019-12-06 2020-12-11 长春博超汽车零部件股份有限公司 Fiber felt, fiber board and preparation device and method thereof
CN111517901B (en) * 2020-04-28 2021-10-22 湖北航天化学技术研究所 High-activity multilayer composite microsphere and preparation method thereof

Family Cites Families (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE661981A (en) * 1964-04-03
US3615972A (en) * 1967-04-28 1971-10-26 Dow Chemical Co Expansible thermoplastic polymer particles containing volatile fluid foaming agent and method of foaming the same
BE758373A (en) * 1967-11-27 1971-05-03 Dow Chemical Co PAPER MANUFACTURING PROCESS
US3779951A (en) * 1972-11-21 1973-12-18 Dow Chemical Co Method for expanding microspheres and expandable composition
SE389696B (en) * 1973-10-26 1976-11-15 Kema Nord Ab PROCEDURE FOR PAPER PAPER CONTAINING PLASTIC PARTICLES
US4133688A (en) * 1975-01-24 1979-01-09 Felix Schoeller, Jr. Photographic carrier material containing thermoplastic microspheres
US3945956A (en) * 1975-06-23 1976-03-23 The Dow Chemical Company Polymerization of styrene acrylonitrile expandable microspheres
DE2921011C2 (en) * 1979-05-23 1981-04-23 Matsumoto Yushi-Seiyaku Co., Ltd., Yao, Osaka Method for creating a relief
SE8204595L (en) * 1982-08-05 1984-02-06 Kema Nord Ab PROCEDURE FOR THE PREPARATION OF HEART-IMPREGNATED FIBER COMPOSITION MATERIAL
US5125996A (en) * 1990-08-27 1992-06-30 Eastman Kodak Company Three dimensional imaging paper
SE9003600L (en) * 1990-11-12 1992-05-13 Casco Nobel Ab EXPANDABLE THERMOPLASTIC MICROSPHERES AND PROCEDURES FOR PRODUCING THEREOF
JP3659979B2 (en) 1992-04-15 2005-06-15 松本油脂製薬株式会社 Thermally expandable microcapsule and its production method
JPH09324399A (en) * 1996-06-04 1997-12-16 Oji Paper Co Ltd Production of pulp mold
US6379497B1 (en) 1996-09-20 2002-04-30 Fort James Corporation Bulk enhanced paperboard and shaped products made therefrom
EP1054034B2 (en) * 1998-01-26 2007-12-12 Kureha Corporation Expandable microspheres and process for producing the same
JP4460768B2 (en) * 1998-02-24 2010-05-12 松本油脂製薬株式会社 Thermally expandable microcapsule, method for producing the same and method for using the same
JP4172871B2 (en) * 1998-02-24 2008-10-29 松本油脂製薬株式会社 Thermally expandable microcapsule and method for producing the same
US6235800B1 (en) * 1998-03-13 2001-05-22 Matsumoto Yushi-Seiyaku Co., Ltd. Heat-expandable microcapsules and method of utilizing the same
WO2001045940A1 (en) * 1999-12-22 2001-06-28 Akzo Nobel N.V. Abrasion-resistant decor sheet
US6866906B2 (en) * 2000-01-26 2005-03-15 International Paper Company Cut resistant paper and paper articles and method for making same
RU2243308C2 (en) * 2000-01-26 2004-12-27 Интернэшнл Пэйпер Компани Items made out of paperboard of low density
US6497787B1 (en) * 2000-04-18 2002-12-24 Owens-Corning Veil Netherlands B.V. Process of manufacturing a wet-laid veil
US6509384B2 (en) * 2000-04-28 2003-01-21 Akzo Nobel N.V. Chemical product and method
US7252882B2 (en) * 2000-04-28 2007-08-07 Kureha Corporation Thermally foamable microsphere and production process thereof
US6582633B2 (en) * 2001-01-17 2003-06-24 Akzo Nobel N.V. Process for producing objects
CN1265055C (en) * 2001-04-11 2006-07-19 国际纸业公司 Cut resistant paper and paper articles and method for making same
JP4721596B2 (en) * 2001-09-28 2011-07-13 株式会社クレハ Low density foamed paper and method for producing the same
JP3826772B2 (en) * 2001-11-20 2006-09-27 凸版印刷株式会社 Thermally expandable laminate and foamed paper container using the laminate

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2004113613A1 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2295390A1 (en) 2009-09-04 2011-03-16 Manfred Jaeckel Method for producing a cellular sinter mould
DE102009040258A1 (en) 2009-09-04 2011-03-24 Jaeckel, Manfred, Dipl.-Ing. Process for producing a cellular sintered body
EP2679564A1 (en) 2009-09-04 2014-01-01 Manfred Jaeckel Method for producing a cellular sinter mould

Also Published As

Publication number Publication date
NO20060372L (en) 2006-01-24
CN1813105A (en) 2006-08-02
JP2007521410A (en) 2007-08-02
KR100826419B1 (en) 2008-04-29
CA2529139A1 (en) 2004-12-29
KR20060028774A (en) 2006-04-03
US20060102307A1 (en) 2006-05-18
WO2004113613A1 (en) 2004-12-29

Similar Documents

Publication Publication Date Title
KR100826419B1 (en) Microspheres
US8388809B2 (en) Microspheres
EP2026902B1 (en) Microspheres
EP1981631B1 (en) Microspheres
US9062170B2 (en) Microspheres
EP1981630B1 (en) Microspheres
US20060000569A1 (en) Microspheres
US20070287776A1 (en) Microspheres
CA2591874C (en) Microsphere and thickener containing composition and its use in the production of paper
MX2008010292A (en) Microspheres

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20051123

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL HR LT LV MK

RIN1 Information on inventor provided before grant (corrected)

Inventor name: ERIKSSON, INGELA

Inventor name: SOEDERBERG, OERJAN

Inventor name: KRON, ANNA

17Q First examination report despatched

Effective date: 20090129

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20101231