EP4662259A1 - Blocked polyisocyanates - Google Patents

Blocked polyisocyanates

Info

Publication number
EP4662259A1
EP4662259A1 EP24705597.3A EP24705597A EP4662259A1 EP 4662259 A1 EP4662259 A1 EP 4662259A1 EP 24705597 A EP24705597 A EP 24705597A EP 4662259 A1 EP4662259 A1 EP 4662259A1
Authority
EP
European Patent Office
Prior art keywords
weight
ionic
aqueous dispersion
blocked polyisocyanates
polyisocyanate
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.)
Pending
Application number
EP24705597.3A
Other languages
German (de)
French (fr)
Inventor
Stefano CARBONI
Riccardo CAPRIFOGLIO
Karine Coget
Thomas Gallo
Marco Luoni
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.)
Lamberti SpA
Original Assignee
Lamberti SpA
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 Lamberti SpA filed Critical Lamberti SpA
Publication of EP4662259A1 publication Critical patent/EP4662259A1/en
Pending legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/08—Processes
    • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/2805—Compounds having only one group containing active hydrogen
    • C08G18/285—Nitrogen containing compounds
    • C08G18/2865—Compounds having only one primary or secondary amino group; Ammonia
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/48—Polyethers
    • C08G18/4833—Polyethers containing oxyethylene units
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/703—Isocyanates or isothiocyanates transformed in a latent form by physical means
    • C08G18/705—Dispersions of isocyanates or isothiocyanates in a liquid medium
    • C08G18/706—Dispersions of isocyanates or isothiocyanates in a liquid medium the liquid medium being water
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/72—Polyisocyanates or polyisothiocyanates
    • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
    • C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
    • C08G18/7614—Polyisocyanates or polyisothiocyanates cyclic aromatic containing only one aromatic ring
    • C08G18/7621—Polyisocyanates or polyisothiocyanates cyclic aromatic containing only one aromatic ring being toluene diisocyanate including isomer mixtures
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/72—Polyisocyanates or polyisothiocyanates
    • C08G18/80—Masked polyisocyanates
    • C08G18/8061—Masked polyisocyanates masked with compounds having only one group containing active hydrogen
    • C08G18/807—Masked polyisocyanates masked with compounds having only one group containing active hydrogen with nitrogen containing compounds
    • C08G18/808—Monoamines
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
    • D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
    • D06M15/37—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D06M15/564—Polyureas, polyurethanes or other polymers having ureide or urethane links; Precondensation products forming them
    • D06M15/568—Reaction products of isocyanates with polyethers
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
    • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
    • D06P1/44—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders
    • D06P1/52—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders using compositions containing synthetic macromolecular substances
    • D06P1/5264—Macromolecular compounds obtained otherwise than by reactions involving only unsaturated carbon-to-carbon bonds
    • D06P1/5285—Polyurethanes; Polyurea; Polyguanides

Definitions

  • the present invention relates to stable aqueous dispersions of non-ionic blocked polyisocyanates obtained by reacting a polyisocyanate composition, a specific non-ionic alkoxylated diol and N-dibutyl amine as blocking agent.
  • the invention also relates to oil- and/or water-repellent textile finishing compositions and textile printing pastes comprising said aqueous dispersions.
  • oil- and/or water-repellent finishing agents such as fluorocarbon emulsions and/or dispersions to be applied onto the article by thermal treatment
  • oil- and/or water-repellent finishing agents are often formulated with aqueous dispersion of blocked polyisocyanates.
  • the isocyanate groups are temporarily reacted with protective groups, so that no reaction of the isocyanate group occurs under normal storage conditions (e.g. 0-80°C).
  • the blocked polyisocyanates e.g. by raising the temperature to the de-blocking or higher temperature, e.g. to >80°C (typically during or after application on the textile of the oil- and/or water-repellent finishing agent that contains the blocked polyisocyanate)
  • the protective groups are detached, the regenerated isocyanate groups are thus able to cross-link the oil- and/or water-repellent agent and to fix it to the textile substrate.
  • the point in time of the crosslinking or bonding can be selected as desired by adjusting the activation conditions.
  • the formulations of oil- and/or water-repellent finishing agents with aqueous blocked polyisocyanates enhances the amount of finished materials which is fixed to the textile and improves considerably its resistance to wear and washing.
  • Cationic, anionic or hydrophilic non-ionionic groups can be incorporated in significant amounts in the blocked polyisocyanate to stabilise their dispersions, but such groups partially impair the hydrophobic treatment of textiles, since the hydrophilic groups exhibit a strong rewetting effect, meaning that the desired water-repelling effect cannot be achieved.
  • WO 2004/050736 discloses a method for solving the stability problem of aqueous dispersions of non-ionic blocked polyisocyanates by incorporating non-ionic, alkoxylated, 1,2- or 1,3-diols and by the use of blocking agents of the reversible kind, such as the compounds containing active methylenic groups (such as the derivatives of malonic acid and its esters, acetylacetone, acetoacetic acid and its esters); oximes; e- caprolactames and lactames; pyrazoles; and imidazoles. Oximes and pyrazoles being preferred, in particular butanone oxime and 3,5- dimethylpyrazole,.
  • aqueous dispersions of the invention are especially useful in combination with oil- and/or water-repellent finishing agent, such as organic perfluorinated polymeric compounds, in the oil- and/or water-repellent finishing of textiles, as they provide an excellent fixing of finishing agent on textiles and high washing stability.
  • oil- and/or water-repellent finishing agent such as organic perfluorinated polymeric compounds
  • aqueous dispersions of non-ionic blocked polyisocyanates of the invention possess a good compatibility with other adjuvants normally used in textile finishing, independently from their ionicity.
  • these dispersions are also useful as cross-linkers for textile printing pastes.
  • stable dispersions we mean dispersions having average particle diameters (by volume) lower than 1000 nm and that do not show sedimentation after one month at 40 °C.
  • aromatic polyisocyanates examples include toluene diisocyanate (e.g. 2,4-TDI, 2,6-TDI and their mixtures), di phenyl methane diisocyanate (e.g.4,4'-MDI, 2,4'-M DI, 2,2'- MDI), naphthalene-1,5-diisocyanate (NDI), meta-tetramethylxilylene diisocyanate, and mixtures thereof.
  • Toluene diisocyanate and diphenylmethane diisocyanate are preferred. Toluene diisocyanate being the most preferred.
  • Suitable aliphatic polyisocyanates include hexamethylene diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate and 2,4,4-trimethyl-hexamethylene diisocyanate. Hexamethylene diisocyanate is preferred.
  • step II) the oligomer obtained in step I) is then reacted with an amount of N-dibutyl amine such that the equivalent ratio of the isocyanate groups of the oligomer and the blocking agent is from 1:0.50 to 1:1.20, preferably from 1:0.80 to 1:1.20, more preferably from 1:0.97 to 1:1.20 and most preferably from 1:0.99 to 1:1.10.
  • the blocked polyisocyanate obtained from step II) is dispersed into water under vigorous stirring to obtain a dispersion having a solid content of from 15 to 50% by weight, preferably from 20 to 40% by weight, more preferably from 25 to 35% by weight.
  • Step II I of the process according to the invention may be preceded by dilution of the reaction mixture obtained in step I I) with from 0.05 to 0.50 parts by weight of a water-mixable polar solvent, said solvent being possibly and preferably completely removed by distillation after completing of step I I I);
  • a water-mixable polar solvent such as methyl ethyl ketone, acetone, cyclohexanone, glycol ethers.
  • the process of the invention allows the direct preparation of aqueous dispersions of stable non-ionic blocked polyisocyanates without the need of emulsifiers, surfactants or external dispersants.
  • the aqueous dispersion can advantageously contain from 0.1 to 5.0 % by weight, based on the total weight of the dispersion, of a dispersant.
  • a dispersant examples include non-ionic, amphoteric and anionic surfactant, such as alkoxylated fatty alcohols, alkyl polyglycoside, amine and aminoamide oxides, salts of alkoxylated fatty alcohols sulfates, salt of alkoxylated fatty alcohols sulfosuccinates and salts of alkoxylated fatty alcohols phosphates.
  • Sodium 2-[(2-aminoethyl)-amino]ethane sulfonate is another example of suitable dispersant.
  • the solid content of the aqueous dispersions of non-ionic blocked polyisocyanates essentially consists of the blocked polyisocyanate and optional dispersant.
  • the water content of the aqueous dispersions of non-ionic blocked polyisocyanate is complementary to the solid content, the aqueous dispersion being devoid of any solvents.
  • the aqueous dispersions of blocked non-ionic polyisocyanates of the invention can advantageously be used in the preparation of textile finishing compositions, and particularly in the preparation oil- and/or water-repellent textile finishing compositions.
  • the finishing agent used in the compositions according to the invention necessary for achieving a water-repellent effect, can, or do not, contain fluorine.
  • a fluorocontaining finishing agent such as a perfluorinated polymeric compounds (i.e. a polymeric compound obtained from polymerizable perfluoroalkyl substances). Suitable perfluorinated polymeric compounds are those normally used for these applications; among them we cite:
  • the oil- and/or water-repellent textile finishing agent of the invention can also comprise fluorine-free finishing agents.
  • fluorine-free finishing agents are natural and synthetic waxes, such as, for example, Ca-Cso polyolefines, (co)polymer of hydrophobic acrylate monomers, such as, for example, C1-C22 alkyl (meth)acrylates copolymers; polyurethanes; fatty-acid modified melamines; organopolysiloxanes; metal salts of fatty acids; fatty acid condensation products; or combinations thereof.
  • the oil- and/or water-repellent textile finishing agent comprises at least one perfluorinated polymeric compound.
  • the aqueous dispersions of the invention are normally used in an amount of from 1 to 50 g/l, preferably from 3 to 30 g/l, based on the total volume of the composition.
  • the weight ratio between the solid fractions of the aqueous dispersion of the invention and the finishing agent in the oil- and/or water-repellent compositions is comprised between 1:1 and 1:12, more preferably between 1:2 and 1:7.
  • the finishing step can be performed by using the conventional techniques, for example by impregnation or spray technique, followed by heat treatment at 130-200 °C for 0.5 - 6 minutes.
  • compositions for the oil- and/or water-repellent finishing of texiles containing the aqueous dispersions of the invention are stable and the textiles treated therewith exhibit high washing stability.
  • aqueous dispersions of blocked polyisocyanate of the invention are moreover particularly useful as cross-linkers for textile printing pastes, giving high colour and washing fastness to the printed textiles.
  • the aqueous dispersions of the invention are used in an amount of from 3 to 50 g/kg, preferably of from 8 to 35 g/kg, based on the total weight of the paste.
  • the printing paste of the invention comprise also a pigment.
  • pigment includes insoluble, finely divided substances, such as titanium dioxide, normally used to colour fibers, yarns or fabrics.
  • Useful pigments include all known, customary textile printing pigments which are commercially available and are well known to the skilled person.
  • pigments can be based on azo or phthalocyanine compounds.
  • DM PA Dimethylol Propionic Acid
  • DIBA N-Di-n-Butyl Amine
  • DM P Dimethyl Pyrazole
  • MEKO Methyl Ethyl Ketoxime
  • DMM Dipropyleneglycol Dimethyl Ether
  • TEA T riethyl Amine
  • EVS-10 Sodium 2-[(2-aminoethyl)-amino]ethane Sulfonate
  • the residual NCO content before the reaction with the blocking agent was determined according to the ASTM D2572 standard method.
  • the stability of the dispersion was determined by storing the dispersion at 40 °C for 1 month.
  • the determination of the content of the blocking agent content was carried out by means of ion exchange chromatography.
  • a ICS 5000 DC ion chromatograph equipped with a Corona® Veo® Charged Aerosol Detector (Thermo Scientific) and an lonpac CS17 + Guard column were used.
  • a 70% TFA 100 mM /25 % H2O / 5 % AcCN solution at a flow of 1.0 ml/min was used as eluent.
  • the sample solutions were
  • the average particle size by volume of the blocked non-ionic polyisocyanate dispersions was determined with a Coulter N4 Plus.
  • a reaction vessel equipped with internal thermometer, stirrer and cooler, was filled, under nitrogen atmosphere and at room temperature with 238.01 g (610.5 meq) of PIC 1 and 50.79 g of DMM, then 82.34 g (109.8 meq) of PE 1 were added under stirring.
  • the reaction temperature was increased to 65 °C and maintained at 60-65 °C for about two hours, until the titrimetric determination of the free NCO-groups gave a value of 6.94 % by weight (NCO-Int).
  • the temperature was reduced to 40 °C and, subsequently, 79.55 g (500.7 meq) of DI BA were added dropwise over a period of about 1 hour.
  • the blocked non-ionic polyisocyanate was checked to be NCO- negative according to the IR analysis and it was dispersed into demineralised water (689.12 g) in the presence of EVS-10 (8.63 g) under high stirring speed.
  • Example 2 The percentage by weight of ethylene oxide groups related to the solids was of 21%.
  • the reaction temperature was increased to 65°C and maintained at 60-65 °C for about two hours, until the value of NCO-Int was 11.4 % by weight.
  • the temperature was reduced to 40 °C and subsequently 109.57 g (427.2 meq) of DBA are added dropwise over a period of about 1 hour.
  • the prepolymer was checked to be NCO-negative according to the IR analysis and 5.70 g (28.4meq) of TEA was added dropwise. After five minutes of stirring the polymer was dispersed into demineralised water (852.19 g) in presence of CAPAO (19.5 g) under high stirring speed.
  • a stable finely divided dispersion was obtained having a solid content of about 30% by weight and a pH of 7.0 and with an average particle size of 66 nm.
  • the dispersion of blocked polyisocyanate of Example 11 was prepared following the same procedure of Example 2 using DIPA as blocking agent.
  • Table 1 lists the polyisocyanates, polyethers and blocking agents used in the preparation of the blocked polyisocyanate dispersions of Examples. Furthermore, it reports the content of NCO groups (in wt%) before the reaction with the blocking agent and the stability of the obtained dispersions.
  • Example 1 The dispersion of Example 1, according to the invention, showed a content of free DI BA of 0.3 % by weight.
  • the dispersions of comparative Examples 6 and 11 showed a content of free DI PA higher than 4 % by weight.
  • the printing pastes were applied on white cotton fabrics on a Zimmer magnetic table, using a 55 threads/cm screen and a 6 mm steel rod at a rate of 50, a pressure of 3, single passage.
  • the printed fabrics were treated in a Mathis-Werner oven at 85, 100, 120, 140 and 160 °C for 2.0 min.
  • the treated printed fabrics were subject to 3 cycles of washing at 60 °C in accordance with the standard method AATCCTM135-2O18T (Test Method for Dimensional Changes of Fabrics after Home Laundering).
  • the colour change of the printed fabrics were determined spectrophotometrically with a Datacolor Spectraflash DE 600.
  • the results (Table 3) are given as a value on the Gray Scale from 1 to 5 (1 very bad - 5 excellent).
  • the grey value is directly related to the deblocking of the polyisocyanate and allows to indirectly determine its de-blocking temperature.
  • the product is considered de-blocked at a value greater than 3.
  • Table 3 reports the de-blocking temperature in °C of the blocked polyisocyanates of the Examples.
  • Table 4 shows the de-blocking efficiency evaluated with spectrophotometric analysis of the printed fabrics after 3 washing cycles at 60°C. The higher the value, the greater the crosslinking efficiency of the polyisocyantes of the Examples at the given temperature. Table 4 * Comparative
  • the water repellency performances of the finishing composition comprising the dispersions of the Examples were evaluated according to the standard method: AATCC TM22-2017e, Test Method for Water Repellency: Spray. Test.
  • Cotton fabrics were impregnated at Foulard with aqueous finishing compositions (Table 5 in g/l) comprising the dispersion of the Examples and a water-based fluorinated polymer emulsion (Hexafor T-63) or a fluorine-free polymer emulsion (Hydrosin NF-18). See Table 5 (in g/l)
  • the impregnated fabrics were then squeezed in the padding mangle to an approximately 50 % liquor pick-up, dried and treated at 160 °C for 2.0 minutes.
  • the water-repellency performances of the fabrics was also evaluated after 30 washing cycles at 40 °C according to the standard method AATCC TM135-2O18T (Test Method for Dimensional Changes of Fabrics after Home Laundering). After drying, the fabrics reactivated with a 2.0 min treatment at 160 °C and then tested (C6-3O and C0-30). Table 6 reports the results obtained with the various dispersions.
  • the dispersion comprising aromatic polyisocyanates blocked with N-dibutyl amine show water-repellency performances similar or superior to those comprising polyisocyanates blocked with prior art blocking agents, such as M EKO or 2-POO.
  • the performance of the blocked polyisocyanate dispersions of the Examples can be also evaluated by determining the stiffness of a fabric impregnated with a simple water solution of the dispersions.
  • white cotton fabrics were impregnated and squeezed with a foulard loaded with a 150 g/L solution of blocked polyisocyanate dispersions. The fabrics were then dried and treated at 160°C for 2.0 min.
  • the dispersions containing blocked aromatic polyisocyanates always give a higher stiffening than dispersion comprising blocked aliphatic polyisocyanates.
  • the dispersions comprising aromatic polyisocyanates blocked with N-dibutyl amine show cross-linking efficiency similar or superior to the one containing polyisocyanates blocked with MEKO.

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  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Dispersion Chemistry (AREA)
  • Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
  • Polyurethanes Or Polyureas (AREA)

Abstract

Stable aqueous dispersions of non-ionic blocked polyisocyanates obtained by reacting i) an aromatic polyisocyanate composition, ii) a specific non-ionic alkoxylated diol and iii) N-dibutyl amine as blocking agent, and oil- and/or water-repellent textile finishing compositions comprising said aqueous dispersions provide an excellent fixing of the finishing agent on textiles and high washing stability.

Description

BLOCKED POLYISOCYANATES
TECHNICAL FIELD
The present invention relates to stable aqueous dispersions of non-ionic blocked polyisocyanates obtained by reacting a polyisocyanate composition, a specific non-ionic alkoxylated diol and N-dibutyl amine as blocking agent. The invention also relates to oil- and/or water-repellent textile finishing compositions and textile printing pastes comprising said aqueous dispersions.
PRIOR ART
The use of aqueous dispersions of blocked polyisocyanates in textile, paint and coating industry is well known.
By way of example, oil- and/or water-repellent finishing agents (such as fluorocarbon emulsions and/or dispersions to be applied onto the article by thermal treatment) are often formulated with aqueous dispersion of blocked polyisocyanates.
In the blocked polyisocyanates, the isocyanate groups are temporarily reacted with protective groups, so that no reaction of the isocyanate group occurs under normal storage conditions (e.g. 0-80°C). By activating the blocked polyisocyanates, e.g. by raising the temperature to the de-blocking or higher temperature, e.g. to >80°C (typically during or after application on the textile of the oil- and/or water-repellent finishing agent that contains the blocked polyisocyanate), the protective groups are detached, the regenerated isocyanate groups are thus able to cross-link the oil- and/or water-repellent agent and to fix it to the textile substrate. The point in time of the crosslinking or bonding (fixing) can be selected as desired by adjusting the activation conditions. As a result, the formulations of oil- and/or water-repellent finishing agents with aqueous blocked polyisocyanates enhances the amount of finished materials which is fixed to the textile and improves considerably its resistance to wear and washing.
One of the problems often encountered in the formulation of aqueous dispersions of non-ionic blocked polyisocyanates for use in hydro-repellent finishes is their stabilization.
Cationic, anionic or hydrophilic non-ionionic groups can be incorporated in significant amounts in the blocked polyisocyanate to stabilise their dispersions, but such groups partially impair the hydrophobic treatment of textiles, since the hydrophilic groups exhibit a strong rewetting effect, meaning that the desired water-repelling effect cannot be achieved.
WO 2004/050736 discloses a method for solving the stability problem of aqueous dispersions of non-ionic blocked polyisocyanates by incorporating non-ionic, alkoxylated, 1,2- or 1,3-diols and by the use of blocking agents of the reversible kind, such as the compounds containing active methylenic groups (such as the derivatives of malonic acid and its esters, acetylacetone, acetoacetic acid and its esters); oximes; e- caprolactames and lactames; pyrazoles; and imidazoles. Oximes and pyrazoles being preferred, in particular butanone oxime and 3,5- dimethylpyrazole,.
Unfortunately, butanone oxime has revealed to be a potential carcinogen. 3,5- dimethylpyrazole, on the other hand, shows a too low de-blocking temperature, especially with aromatic polyisocyanates, and it is also suspected to be harmful to health. Therefore, there is still the need of non-noxious blocking agents which allow the preparations of stable dispersions of non-ionic blocked polyisocyanates that possess the appropriate performances in the oil- and/or water-repellent finishing of textile products. It has now been found that the aqueous dispersions of non-ionic blocked polyisocyanates obtained from the reaction of an aromatic polyisocyanate composition, N-dibutyl amine as blocking agent and the specific non-ionic alkoxylated 1,2- or 1,3-diols of WO 2004/050736 show at least the same stability of dispersions of non-ionic analogous polyisocyanates blocked with oxime or pyrazole groups. Said dispersions are more stable than the dispersions of analogous polyisocyanates blocked with different disubstituted amines and are particularly suited for the use in the textile field, in particular for the preparation of textile finishing compositions.
The aqueous dispersions of the invention are especially useful in combination with oil- and/or water-repellent finishing agent, such as organic perfluorinated polymeric compounds, in the oil- and/or water-repellent finishing of textiles, as they provide an excellent fixing of finishing agent on textiles and high washing stability.
In addition, the aqueous dispersions of non-ionic blocked polyisocyanates of the invention, unlike the analogous ionic compounds, possess a good compatibility with other adjuvants normally used in textile finishing, independently from their ionicity. Finally, these dispersions are also useful as cross-linkers for textile printing pastes.
In the present text with the expression "stable dispersions" we mean dispersions having average particle diameters (by volume) lower than 1000 nm and that do not show sedimentation after one month at 40 °C.
DESCRIPTION OF THE INVENTION
It is therefore an object of the present invention an aqueous dispersion of non-ionic blocked polyisocyanates obtained from the reaction of:
A) a polyisocyanate composition comprising at least 60 % by weight of an aromatic polyisocyanate;
B) a non-ionic alkoxylated diol having general formula I:
R1CH2O-(-CH2CH2O)n-(CH2CHCH3O)m-R2
(I) wherein: or
R2 and R3 are equal or different and are chosen among methyl, ethyl, n-propyl, i- propyl, n-butyl and i-butyl; n is a number from 0 to 40; m is a number from 0 to 40; n + m is a number from 20 to 80, preferably from 20 to 40;
C) N-dibutyl amine as blocking agent, the dispersion having a solid content of from 15 to 50% by weight, preferably from 20 to 40% by weight, more preferably from 25 to 35% by weight.
Textile finishing compositions comprising, based on the total volume of the composition: a) from 1 to 50 g/l of said aqueous dispersion; b) at least one oil- and/or water-repellent finishing agent; are another object of the invention.
Textile printing pastes comprising, based on the total weight of the composition: a1) from 3 to 50 g/kg of said aqueous dispersion; b1) at least one pigment; are a further object of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The stability of the aqueous dispersions of the present invention is the more unexpected as the use of the analogue dialkyl amines, instead of the N-dibutyl amine, leads to the obtainment of unstable dispersions, that are not suited for the industrial use.
The polyisocyanate composition suitable for the preparation of the aqueous dispersion of non-ionic blocked polyisocyanates of the invention comprises at least 60 % by weight, preferably at least 70 % by weight, more preferably at least 80 % by weight, and most preferably 100 % by weight of aromatic polyisocyanates; the remaining part, when present, being made of polyisocyates of the aliphatic, or the cycloaliphatic type or mixtures thereof.
A polyisocyanate within the meaning of the invention is considered to be a basic structure with at least two free isocyanate groups. The suitable polyisocyanates are those commercially available and contain from 2 to 10 isocyanate groups per molecule. By "aromatic polyisocyanate" we mean a polyisocyanate containing at least one aromatic ring.
Examples of suitable aromatic polyisocyanates are toluene diisocyanate (e.g. 2,4-TDI, 2,6-TDI and their mixtures), di phenyl methane diisocyanate (e.g.4,4'-MDI, 2,4'-M DI, 2,2'- MDI), naphthalene-1,5-diisocyanate (NDI), meta-tetramethylxilylene diisocyanate, and mixtures thereof. Toluene diisocyanate and diphenylmethane diisocyanate are preferred. Toluene diisocyanate being the most preferred. Examples of suitable aliphatic polyisocyanates include hexamethylene diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate and 2,4,4-trimethyl-hexamethylene diisocyanate. Hexamethylene diisocyanate is preferred.
Examples of suitable cycloaliphatic polyisocyanates are 1-isocyanate-3-isocyanate- methyl-3,5,5-trimethyl-cyclohexane (or isophorone diisocyanate), 4,4'-dicyclohexyl- methanediisocyanate, 2,4-cyclohexyldiisocyanate and 2,6-cyclohexyldiisocyanate. Isophorone diisocyanate is preferred.
Other examples of suitable polyisocyanates include tri- and higher-functionalised polyisocyanates, such as triphenylmethane-4,4',4"-triisocyanate or compounds obtained by condensation of trimethylol propane or other polyols having functionality functionality greater than or equal to three, with the above diisocyanates, in particular with aromatic diisocyanates.
Further examples of suitable polyisocyanates include compounds containing at least three isocyanate groups per molecule obtained by trimerization, biuretization, urethanization or allophanation of the polyisocyanates described above.
According to a preferred embodiment, the polyisocyanate composition comprises at least 60 % by weight of polyisocyanates obtained by condensation of trimethylol propane or other polyols having functionality greater than or equal to three and aromatic diisocyanates whereuin the toluene diisocyanate (2,4-TDI, 2,6-TDI and their mixtures) is the preferred aromatic diisocyanate.
More preferably, polyisocyanate composition comprises at least 60 % by weight, preferably at least 70 % by weight, more preferably at least 80 % by weight, and most preferably 100 % by weight, of the polyisocyanates obtained by condensation of trimethylol propane and toluene diisocyanate, such as Polurene® AD from S.A.P.I.C.I. S.p.A., Italy.
The preferred non-ionic alkoxylated diols useful for the preparation of the non-ionic blocked polyisocyanate of the invention have the general formula I:
R1CH2O-(-CH2CH2O)n-(CH2CHCH3O)m-R2
(I) wherein:
R2 is methyl, R3 is ethyl, n is a number from 15 to 30 and m is a number from 0 to 10.
Examples of said diols are the commercially available Tegomer® D-3403 and Tegomer® D-3123 from Evonik Operations GmbH (DE).
In the definition N-dibutyl amine, the term dibutyl includes all possible isomers of the butyl radical, namely n-butyl, sec-butyl, iso-butyl and tert-butyl. Also included are amines substituted with two different butyl isomers. N-di-n-butyl amine is the preferred N-dibutyl amine.
The aqueous dispersions of non-ionic blocked polyisocyanates of the invention can be prepared following a process-comprising the following steps:
I) a polyisocyanate composition comprising at least 60 % by weight of an aromatic polyisocyanate and a non-ionic alkoxylated diol of the general formula (I) as described above are reacted at a temperature of 0-120 °C, their equivalent ratio being such that the percentage by weight of free isocyanate groups in the resulting oligomer is from 3 to 10 % and the percentage in weight of ethoxyl groups is from 10 to 40 %, preferably from 20 to 30%;
II) the oligomer obtained in step I) is then reacted with an amount of N-dibutyl amine such that the equivalent ratio of the isocyanate groups of the oligomer and the blocking agent is from 1:0.50 to 1:1.20, preferably from 1:0.80 to 1:1.20, more preferably from 1:0.97 to 1:1.20 and most preferably from 1:0.99 to 1:1.10.
III) the blocked polyisocyanate obtained from step II) is dispersed into water under vigorous stirring to obtain a dispersion having a solid content of from 15 to 50% by weight, preferably from 20 to 40% by weight, more preferably from 25 to 35% by weight.
Step II I of the process according to the invention may be preceded by dilution of the reaction mixture obtained in step I I) with from 0.05 to 0.50 parts by weight of a water-mixable polar solvent, said solvent being possibly and preferably completely removed by distillation after completing of step I I I); the preferred water-mixable polar solvents are aliphatic ketones, such as methyl ethyl ketone, acetone, cyclohexanone, glycol ethers.
The process of the invention allows the direct preparation of aqueous dispersions of stable non-ionic blocked polyisocyanates without the need of emulsifiers, surfactants or external dispersants.
However, to reduce the final viscosity, the aqueous dispersion can advantageously contain from 0.1 to 5.0 % by weight, based on the total weight of the dispersion, of a dispersant. Examples useful dispersants are non-ionic, amphoteric and anionic surfactant, such as alkoxylated fatty alcohols, alkyl polyglycoside, amine and aminoamide oxides, salts of alkoxylated fatty alcohols sulfates, salt of alkoxylated fatty alcohols sulfosuccinates and salts of alkoxylated fatty alcohols phosphates. Oxides of aminoamides with alkyl chains greater than or equal to C10, and in particular cocoamidopropylamine oxide (CAS Number: 68155-09-9), are among the preferred suitable dispersants. Sodium 2-[(2-aminoethyl)-amino]ethane sulfonate is another example of suitable dispersant.
The solid content of the aqueous dispersions of non-ionic blocked polyisocyanates essentially consists of the blocked polyisocyanate and optional dispersant.
Most preferably, the water content of the aqueous dispersions of non-ionic blocked polyisocyanate is complementary to the solid content, the aqueous dispersion being devoid of any solvents.
The aqueous dispersions of blocked non-ionic polyisocyanates of the invention can advantageously be used in the preparation of textile finishing compositions, and particularly in the preparation oil- and/or water-repellent textile finishing compositions. The finishing agent used in the compositions according to the invention, necessary for achieving a water-repellent effect, can, or do not, contain fluorine. To achieve an oilrepellent effect, however, it is preferred for the compositions to contain a fluorocontaining finishing agent, such as a perfluorinated polymeric compounds (i.e. a polymeric compound obtained from polymerizable perfluoroalkyl substances). Suitable perfluorinated polymeric compounds are those normally used for these applications; among them we cite:
1) homopolymers of acrylic monomers having general formula: CnF2n+lCH2CH2OC(O)-C(R) = CH2 wherein R is methyl or hydrogen and n is a number from 5 to 12;
2) homopolymers of acrylic monomers having general formula: CnF2n+iSO2N(R')-CH2CH2OC(O)-C(R)=CH2 wherein R and R' are an alkyl group or hydrogen and n is a number from 5 to 12.
3) copolymers of the above cited fluorinated acrylic monomers with: butadiene, isoprene, chloroprene, styrene, a-methylstyrene, p-methylstyrene, vinyl halides (such as vinyl chloride, vinylidene chloride, vinylidene fluoride), vinyl esters (such as vinyl acetate, vinyl propionate, vinyl stearate), vinyl methyl ketones, esters of acrylic or methacrylic acid (such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate or methacrylate, decyl acrylate, lauryl acrylate or methacrylate, stearyl methacrylate, N,N- dimethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate or glycidyl methacrylate), acrylamide, methacrylamide, N-methylol acrylamide, acrylonitrile, methacrylonitrile, N-substituted maleic imides, acrylates or methacrylates of ethoxylated alcohols having molecular weight smaller than 2000 daltons, or mixture thereof.
The oil- and/or water-repellent textile finishing agent of the invention can also comprise fluorine-free finishing agents. Examples of fluorine-free finishing agents are natural and synthetic waxes, such as, for example, Ca-Cso polyolefines, (co)polymer of hydrophobic acrylate monomers, such as, for example, C1-C22 alkyl (meth)acrylates copolymers; polyurethanes; fatty-acid modified melamines; organopolysiloxanes; metal salts of fatty acids; fatty acid condensation products; or combinations thereof.
In a preferred embodiment of the invention, the oil- and/or water-repellent textile finishing agent comprises at least one perfluorinated polymeric compound.
For the preparation of the compositions useful for the oil- and/or water-repellent finishing of textiles, the aqueous dispersions of the invention are normally used in an amount of from 1 to 50 g/l, preferably from 3 to 30 g/l, based on the total volume of the composition.
Advantageously, the weight ratio between the solid fractions of the aqueous dispersion of the invention and the finishing agent in the oil- and/or water-repellent compositions is comprised between 1:1 and 1:12, more preferably between 1:2 and 1:7.
The finishing step can be performed by using the conventional techniques, for example by impregnation or spray technique, followed by heat treatment at 130-200 °C for 0.5 - 6 minutes.
The compositions for the oil- and/or water-repellent finishing of texiles containing the aqueous dispersions of the invention are stable and the textiles treated therewith exhibit high washing stability.
The aqueous dispersions of blocked polyisocyanate of the invention are moreover particularly useful as cross-linkers for textile printing pastes, giving high colour and washing fastness to the printed textiles.
For the preparation of the printing pastes, the aqueous dispersions of the invention are used in an amount of from 3 to 50 g/kg, preferably of from 8 to 35 g/kg, based on the total weight of the paste.
The printing paste of the invention comprise also a pigment. The term "pigment" includes insoluble, finely divided substances, such as titanium dioxide, normally used to colour fibers, yarns or fabrics.
Useful pigments include all known, customary textile printing pigments which are commercially available and are well known to the skilled person. For example, pigments can be based on azo or phthalocyanine compounds.
The examples that follow are presented to better illustrate the invention.
EXAMPLES
In the examples the following compounds are used:
PE 1 = Tegomer® D-3403, ethoxylated diol having molecular weight 1220 g/mol, commercialized by Evonik Operation Gmbh; • PIC 1 = Polurene® AD, reaction product of trimethylol propane and toluenediisocyanate, having a NCO content of 13.0 ± 0,5% by weight, in ethyl acetate (with an active content of 75% by weight), commercialized by S.A.P.I.C.I. S.p.A. (Italy); HDT-LV = Tolonate® HDT-LV (HDI Trimer), from Vencorex;
M-PEG = Methoxy-Polyethylene Glycol (MW = 750);
DM PA = Dimethylol Propionic Acid;
CL = s-Caprolactam;
DIPA = N-Dipropyl Amine;
DIBA = N-Di-n-Butyl Amine;
DCHA = N-Dicyclohexyl Amine;
DM P = Dimethyl Pyrazole;
MO = Morpholine;
MEKO = Methyl Ethyl Ketoxime;
2-POO = 2-Pentanone Oxime;
PY = Pyrrolidine;
DMM = Dipropyleneglycol Dimethyl Ether;
TEA = T riethyl Amine;
EVS-10 = Sodium 2-[(2-aminoethyl)-amino]ethane Sulfonate;
CAPAO = Cocoamidopropylamine Oxide.
Characterization Method
The residual NCO content before the reaction with the blocking agent was determined according to the ASTM D2572 standard method.
The absence of NCO groups in the final products was evaluated by following the disappearance of the peak at 2265 cm-1 in the IR spectrum.
The stability of the dispersion was determined by storing the dispersion at 40 °C for 1 month.
The determination of the content of the blocking agent content was carried out by means of ion exchange chromatography. A ICS 5000 DC ion chromatograph equipped with a Corona® Veo® Charged Aerosol Detector (Thermo Scientific) and an lonpac CS17 + Guard column were used. A 70% TFA 100 mM /25 % H2O / 5 % AcCN solution at a flow of 1.0 ml/min was used as eluent. The sample solutions were
The average particle size by volume of the blocked non-ionic polyisocyanate dispersions was determined with a Coulter N4 Plus.
A reaction vessel, equipped with internal thermometer, stirrer and cooler, was filled, under nitrogen atmosphere and at room temperature with 238.01 g (610.5 meq) of PIC 1 and 50.79 g of DMM, then 82.34 g (109.8 meq) of PE 1 were added under stirring. The reaction temperature was increased to 65 °C and maintained at 60-65 °C for about two hours, until the titrimetric determination of the free NCO-groups gave a value of 6.94 % by weight (NCO-Int).
The temperature was reduced to 40 °C and, subsequently, 79.55 g (500.7 meq) of DI BA were added dropwise over a period of about 1 hour.
After 1 hour of reaction, the blocked non-ionic polyisocyanate was checked to be NCO- negative according to the IR analysis and it was dispersed into demineralised water (689.12 g) in the presence of EVS-10 (8.63 g) under high stirring speed.
The organic solvent was distilled off under vacuum.
A stable finely divided dispersion having a solid content of 30 % by weight and a pH of 8.20, with an average particle size of 56 nm, was obtained.
The percentage by weight of ethylene oxide groups related to the solids was of 21%. Example 2 reaction vessel, equipped with internal thermometer, stirrer and cooler, was filled, under nitrogen atmosphere and at room temperature with 74.42 g (50.0meq) of M-PEG, 7.56 g (56.8meq) of DMPA and 39.00 g of DM M, then 192.02 g (53.4 meq) of HDT-LV are added under stirring. The reaction temperature was increased to 65°C and maintained at 60-65 °C for about two hours, until the value of NCO-Int was 11.4 % by weight.
The temperature was reduced to 40 °C and subsequently 109.57 g (427.2 meq) of DBA are added dropwise over a period of about 1 hour.
After 1 hour of reaction, the prepolymer was checked to be NCO-negative according to the IR analysis and 5.70 g (28.4meq) of TEA was added dropwise. After five minutes of stirring the polymer was dispersed into demineralised water (852.19 g) in presence of CAPAO (19.5 g) under high stirring speed.
A stable finely divided dispersion was obtained having a solid content of about 30% by weight and a pH of 7.0 and with an average particle size of 66 nm. Examples 3 - 9
The dispersions of blocked polyisocyanates of Examples 3 -9 were prepared following the same procedure of Example 1 using different blocking agents (see Table 1).
Example 10
The dispersion of non-ionic blocked polyisocyanate of Examples 10 was prepared following the same procedure of Example 1 using 8.63 g of CAPAO as dispersing agent.
Example 11
The dispersion of blocked polyisocyanate of Example 11 was prepared following the same procedure of Example 2 using DIPA as blocking agent.
Table 1 lists the polyisocyanates, polyethers and blocking agents used in the preparation of the blocked polyisocyanate dispersions of Examples. Furthermore, it reports the content of NCO groups (in wt%) before the reaction with the blocking agent and the stability of the obtained dispersions.
Table 1
Comparative The stability of the dispersions of the blocked non-ionic polyisocyanates of the invention was further confirmed by the determination of free blocking agent after one month at 40 °C.
The dispersion of Example 1, according to the invention, showed a content of free DI BA of 0.3 % by weight.
The dispersions of comparative Examples 6 and 11 showed a content of free DI PA higher than 4 % by weight.
Application Test
The dispersions of blocked polyisocyanates described in the Examples were used to prepare printing pastes according to the recipe listed in Table 2.
Table 2
Commercialized by Lamberti S.p.A.
The printing pastes were applied on white cotton fabrics on a Zimmer magnetic table, using a 55 threads/cm screen and a 6 mm steel rod at a rate of 50, a pressure of 3, single passage.
After drying, the printed fabrics were treated in a Mathis-Werner oven at 85, 100, 120, 140 and 160 °C for 2.0 min.
After 24 hours at room temperature, the treated printed fabrics were subject to 3 cycles of washing at 60 °C in accordance with the standard method AATCCTM135-2O18T (Test Method for Dimensional Changes of Fabrics after Home Laundering).
A commercial blocked non-ionic polyisocyanate, Hydrosin NF-08, commercialized by MAFLON S.p.A., was used to prepare a further comparative printing paste.
The colour change of the printed fabrics were determined spectrophotometrically with a Datacolor Spectraflash DE 600. The results (Table 3) are given as a value on the Gray Scale from 1 to 5 (1 very bad - 5 excellent). The grey value is directly related to the deblocking of the polyisocyanate and allows to indirectly determine its de-blocking temperature. The product is considered de-blocked at a value greater than 3. Table 3 reports the de-blocking temperature in °C of the blocked polyisocyanates of the Examples.
Table 3 * Comparative
Table 4 shows the de-blocking efficiency evaluated with spectrophotometric analysis of the printed fabrics after 3 washing cycles at 60°C. The higher the value, the greater the crosslinking efficiency of the polyisocyantes of the Examples at the given temperature. Table 4 * Comparative
The results of Table 4 demonstrate that the aromatic polyisocyantes blocked with DI BA and DIPA have lower de-blocking temperatures in comparison with the equivalent aliphatic polyisocyanates.
Other blocking agents, such as caprolactam, begin to unblock around 160°C but their de-blocking efficiency is insufficient. DIPA, which already give slightly unstable dispersion when reacted with aliphatic polyisocyanates, produces a completely unstable dispersion with aromatic polyisocyanates. On the contrary aromatic polyisocyanate blocked with DIBA de-blocks at optimal temperatures without compromising the stability of the dispersions.
Water Repellency Test
The water repellency performances of the finishing composition comprising the dispersions of the Examples were evaluated according to the standard method: AATCC TM22-2017e, Test Method for Water Repellency: Spray. Test.
Cotton fabrics were impregnated at Foulard with aqueous finishing compositions (Table 5 in g/l) comprising the dispersion of the Examples and a water-based fluorinated polymer emulsion (Hexafor T-63) or a fluorine-free polymer emulsion (Hydrosin NF-18). See Table 5 (in g/l)
Table 5
Commercialized by MAFLON S.p.A.
The impregnated fabrics were then squeezed in the padding mangle to an approximately 50 % liquor pick-up, dried and treated at 160 °C for 2.0 minutes.
The water-repellency performances of the fabrics was also evaluated after 30 washing cycles at 40 °C according to the standard method AATCC TM135-2O18T (Test Method for Dimensional Changes of Fabrics after Home Laundering). After drying, the fabrics reactivated with a 2.0 min treatment at 160 °C and then tested (C6-3O and C0-30). Table 6 reports the results obtained with the various dispersions.
Table d
Comparative
Even in the water repellency test, the dispersions of blocked aromatic polyisocyanates show clearly better performance than the aliphatic polyisocyanate. (Comparative Example 2 was not tested because of the too high de-block temperature).
The dispersion comprising aromatic polyisocyanates blocked with N-dibutyl amine show water-repellency performances similar or superior to those comprising polyisocyanates blocked with prior art blocking agents, such as M EKO or 2-POO.
Fabric Impregnation
The performance of the blocked polyisocyanate dispersions of the Examples can be also evaluated by determining the stiffness of a fabric impregnated with a simple water solution of the dispersions.
Accordingly, white cotton fabrics were impregnated and squeezed with a foulard loaded with a 150 g/L solution of blocked polyisocyanate dispersions. The fabrics were then dried and treated at 160°C for 2.0 min.
The stiffness of the fabrics was evaluated after 24 hours of conditioning at room temperature against the untreated fabric (Blank). The results (Table 7) are expressed on an empirical scale ranging from 1 (no difference compared to the Blank) to 5 (strong increase in stiffness). The higher the stiffness, the better the crosslinking efficiency of the polyisocyanate. Table ?
Comparative
The dispersions containing blocked aromatic polyisocyanates always give a higher stiffening than dispersion comprising blocked aliphatic polyisocyanates. Again the dispersions comprising aromatic polyisocyanates blocked with N-dibutyl amine show cross-linking efficiency similar or superior to the one containing polyisocyanates blocked with MEKO.

Claims

1) Aqueous dispersion of non-ionic blocked polyisocyanates obtained from the reaction of:
A) a polyisocyanate composition comprising at least 60 % by weight of an aromatic polyisocyanate;
B) a non-ionic alkoxylated diol having general formula I:
R1CH2O-(-CH2CH2O)n-(CH2CHCH3O)m-R2
(I) wherein: or
R2 and R3 are equal or different and are chosen among methyl, ethyl, n-propyl, i- propyl, n-butyl and i-butyl; n is a number from 0 to 40; m is a number from 0 to 40; n + m is a number from 20 to 80.
C) N-dibutyl amine as blocking agent the dispersion having a solid content of from 15 to 50% by weight.
2) The aqueous dispersion of non-ionic blocked polyisocyanates according to claim 1, wherein n + m is a number from 20 to 40.
3) The aqueous dispersion of non-ionic blocked polyisocyanates according to claim 1, wherein the non-ionic alkoxylated diol has the general formula I:
R1CH2O-(-CH2CH2O)n-(CH2CHCH3O)m-R2 (I) wherein:
R2 is methyl, R3 is ethyl, n is a number from 15 to 30 and m is a number from 0 to 10.
4) The aqueous dispersion of non-ionic blocked polyisocyanates according to claim 1, wherein the polyisocyanate composition comprises at least 70 % by weight of an aromatic polyisocyanate.
5) The aqueous dispersion of non-ionic blocked polyisocyanates according to claim 1, wherein the polyisocyanate composition comprises at least 60 % by weight of polyisocyanates obtained by condensation of trimethylol propane or other polyols having functionality greater than or equal to three and aromatic diisocyanates.
6) The aqueous dispersion of non-ionic blocked polyisocyanates according to claim 5, wherein the polyisocyanate composition comprises at least 60 % by weight of polyisocyanates obtained by condensation of trimethylol propane and toluene diisocyanate.
7) The aqueous dispersion of non-ionic blocked polyisocyanates according to claim 1 having a solid content from 20 to 40% by weight.
8) The aqueous dispersion of non-ionic blocked polyisocyanates according to claim 1 having a solid content from 25 to 35% by weight.
9) Textile finishing compositions, comprising, based on the total volume of the composition: a) from 1 to 50 g/l of an aqueous dispersion of non-ionic blocked polyisocyanates according to any of claims from 1) to 6); b) at least one oil- and/or water-repellent finishing agent.
10) The textile finishing compositions according to claim 7), comprising: a) from 3 to 30 g/l of said aqueous dispersion; b) at least one oil- and/or water-repellent finishing agent. 11) Textile printing pastes, comprising, based on the total weight of the composition: a1) from 3 to 50 g/kg of an aqueous dispersion of non-ionic blocked polyisocyanates according to any of claims from 1) to 6); b1) at least one pigment.
12) The textile printing pastes according to claim 9), comprising: a1) from 8 to 35 g/kg of said aqueous dispersion; b1) at least one pigment.
13) Process for the preparation of aqueous dispersions of non-ionic blocked polyisocyanates comprising the following steps:
I) a polyisocyanate composition comprising at least 60 % by weight of an aromatic polyisocyanate and a non-ionic alkoxylated diol of the general formula (I)
R1CH2O-(-CH2CH2O)n-(CH2CHCH3O)m-R2
(I) wherein:
R2 is methyl, R3 is ethyl, n is a number from 15 to 30 and m is a number from 0 to 10 are reacted at a temperature of 0-120 °C, their equivalent ratio being such that the percentage by weight of free isocyanate groups in the resulting oligomer is from 3 to 10 % and the percentage in weight of ethoxyl groups is from 10 to 40 %;
II) the oligomer obtained in step I) is then reacted with an amount of N-dibutyl amine such that the equivalent ratio of the isocyanate groups of the oligomer and the blocking agent is from 1:0.50 to 1:1.20;
III) the blocked polyisocyanate obtained from step II) is dispersed into water under vigorous stirring to obtain a dispersion having a solid content of from 15 to 50% by weight. 14) Process for the preparation of aqueous dispersions of non-ionic blocked polyisocyanates comprising the following steps:
I) a polyisocyanate composition comprising at least 60 % by weight of an aromatic polyisocyanate and a non-ionic alkoxylated diol of the general formula (I)
R1CH2O-(-CH2CH2O)n-(CH2CHCH3O)m-R2
(I) wherein:
R2 is methyl, R3 is ethyl, n is a number from 15 to 30 and m is a number from 0 to 10 are reacted at a temperature of 0-120 °C, their equivalent ratio being such that the percentage by weight of free isocyanate groups in the resulting oligomer is from 3 to 10 % and the percentage in weight of ethoxyl groups is from 10 to 40 %;
II) the oligomer obtained in step I) is then reacted with an amount of N-dibutyl amine such that the equivalent ratio of the isocyanate groups of the oligomer and the blocking agent is from 1:0.97 to 1:1.20;
III) the blocked polyisocyanate obtained from step II) is dispersed into water under vigorous stirring to obtain a dispersion having a solid content of from 15 to 50% by weight.
EP24705597.3A 2023-02-09 2024-02-06 Blocked polyisocyanates Pending EP4662259A1 (en)

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