Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D1/00—Processes for applying liquids or other fluent materials
  • B05D1/36—Successively applying liquids or other fluent materials, e.g. without intermediate treatment
• • 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
  • C08G18/16—Catalysts
• • 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
  • C08G18/16—Catalysts
  • C08G18/18—Catalysts containing secondary or tertiary amines or salts thereof
• • 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
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/302—Water

Definitions

• HYDRATED CATALYST COMPLEX AND PROCESS This invention relates to the drying of coatings, films and the like. By the invention there is provided an improved process (and resultant product) whereby said drying is carried out more efficaciously than before.
• Two component systems with their infinitely variable formulation possibilities and above average dried film characteristics, have served the purpose well of introducing the VAPOCURE (TM) Process to the industrial coating arena.
• TM VAPOCURE
• This paint by definition, has to be a one component type whose viscosity and other rheological properties remain stable indefinitely while being used in conjunction with a pressurised recirculation system.
• the paint has to cope with being left in the feed lines during extended stoppages, such as breakdowns or holiday periods, and flow at the push of a button when again required.
• the two component system with its finite pot life, its constantly varying viscosity characteristics and its sensitivity to pressure, is clearly unsuitable under these circumstances.
• the one component paint system will rapidly polymerise to give dried films of initial hardness and chemical resistance which overshadow the established bench marks achieved with the two component formulations.
• a one component system needs a finite amount of water to be present if complete polymerisation is to take place.
• the water enters the film in a gaseous state from the air surrounding the painted article, as does the catalyst.
• a concentration gradient needs to exist for this water and also for the catalyst.
• the invention provides a process for forming a dried coating upon a suitable substrate comprising applying a vehicle, such as a one-component vehicle, upon a substrate and subjecting the vehicle to treatment with a drying agent as hereinafter defined.
• a vehicle such as a one-component vehicle
• the invention finds application in the drying of paints, lacquers, varnishes, printing vehicles and printing inks, liquid adhesives, surface coatings, caulking compounds and the like. Definitions 1.
• coating when used as a noun, is, for the purposes of this invention, to be understood as synonymous with “film” (or the like).
• drying includes within its ambit “curing” and (ii) indicates that the coating is either free from “tack”, insoluble in solvent, possessed of an advanced degree of integrity, or able to withstand reasonable abrasion or pressure without damage.
• substrate includes any surface to which the vehicle can be adheringly applied, and upon which it will be retained while treatment with the agent is being effected.
• vehicle includes all paints, lacquers and the like which contain free isocyanate groups.
• drying agent means the agent which effects the drying of the coated vehicle and is multi-component comprising a first component, water, together with at least one further component selected from an amine, or any other hydratable compound - such as an organo metal or inorganic metal salt - which, in association with the water, will accelerate the desired reaction pathway.
• free isocyanate groups includes any compound having potentially free such groups, ie. the pre-polymer has isocyanate groups which are releasable, or available, for reaction with water molecules (for the purposes of polymer propagation and/or film formation); and includes not only polyisocyanates with urethane and urea structure but also those with polyisocyanurate, biuret, and allophanate structure.
• amine includes tertiary amines and alkanolamines and these can either be; a) Polyfunctional, b) Aromatic, C) Aliphatic or Cycloaliphatic in nature. Specific examples are triethylamine and dimethylethanolamine (DMEA) , and ditertiary amines such as N,N,N',N'-tetramethylethylenediamine (TMEDA) and N,N,N',N',2-pentamethyl-1,2-propanediamine (PMT) - and, indeed, any combination of such amines, proportioned as required, whereby advantage may be taken of the synergistic effect of such a combination.
• DMEA triethylamine and dimethylethanolamine
• TMEDA N,N,N',N'-tetramethylethylenediamine
• PMT N,N,N',N',2-pentamethyl-1,2-propanediamine
• the word "atmosphere” relates to the gaseous environment in the drying chamber.
• organo metals examples include dibutyl tin dilaurate, lead tetraethyl, titanium acetyl acetonate, dimethyl tin dichloride, and stannous and zinc octoates.
• inorganic metal salts are bismuth nitrate and ferric chloride.
• the drying agent preferably effects its treatment in the vapour-phase.
• vapour-phase denotes that the agent is in gaseous, vapour, or other entrained air-borne form (e.g. dispersion, fog or aerosol) in which it is available for reaction. Attainment of this phase is achieved by the atomisation of predetermined quantities of water and the selected further component. The concentration levels (of water and further component (s)) may be varied in accordance with situational requirements. However, there appears to be a relationship between the extent of hydrated complex formation and the acceleration of drying. usually a substrate, coated with the vehicle, is subjected to treatment in an atmosphere containing water atomised to provide a Relative humidity level within the range 40%-80% dependant upon the existing temperature which can lie within the range 10°C - 40°C.
• the further component (s) is usually present at a "parts per million” level, and varies with the selected component.
• the "atmosphere” can contain 500 to 5000 parts per million, for TMEDA 250 to 2500 parts per million and PMT 200 to 2000 parts per million.
• the present invention is particularly suitable for the drying of commercially available one-component vehicles. It is well known that one-component systems traditionally require extended periods to reach a full crosslinked state of dryness under ambient (temperature and humidity) conditions as the moisture necessary for curing must permeate into an environment that is essentially hydrophobic. Acceleration of the cure by increasing the temperature has been found to be counterproductive as this has the effect of minimizing available water at reaction sites. These factors previously have made one-component moisture curing systems unviable on a commercial scale.
• the present invention does not merely facilitate the introduction of moisture; rather, it so accelerates the crosslinking reaction that fully dried films can be produced within, for example, 3-4 minutes.
• the exposure of a standard paint test panel, coated with a one-component paint with a thickness up to 100 microns, to an atmosphere of the drying agent of the present invention can result in transition from l iquid to solid in shor tened time periods as indicated above.
• the combustimeter is an apparatus which utilises a change in the resistivity between a reference and an active filament as generated by the heat of combustion of any organic compound in the vapour phase and converts it to an output signal measured in millivolts. The millivolts generated is then propor tonal to the heat of combustion of the compound being tested and its concentration.
• the following tables and graphs indicate the results obtained when specific quantities of five different chemical substances were tested at constant concentrations and varying Relative humidity levels. Initially the output voltage obtained with the apparatus was determined to be zero and independent of Relative humidity from 0 to 100%.
• the concentration of each material in the vapour phase was chosen so that it coincides with optimum output voltages within the range under investigation.
• DMEA is represented by: line A TMEDA is represented by: line B PMT is represented by: line C Solvent Naptha 100 is represented by: line D
• Ethanol is represented by: line E
• the graph for DMEA displays a linear relationship with Relative humidity suggesting that complexing with water molecules is proportional to the cncentration of the two compounds and that the complex formed has in fact an altered heat of combustion to that of anhydrous DMEA itself.
• Two standard paint test panels of rectangular shape (the substrate) were sprayed with a one component white paint, which paint had been previously mixed with the quantity of water calculated as being necessary to effect complete crosslinking.
• the first panel was used as a control panel and allowed to dry in air, while the second panel was used as a test panel and treated as follows:
• test panel was placed in a sealed drying chamber wherein was generated, by injection of carefully metered quantities of DMEA (dimethylethanolamine), an atmosphere of this material having a concentration measured as 1250 parts per million.
• DMEA dimethylethanolamine
• the temperature was maintained at 25°C and the Relative humidity measured at 40%. This environment was recirculated at 1.5 metres per second for a period of two minutes after which a three minute purge cycle commenced. After the purge cycle had evacuated the chamber of the DMEA and replaced it with fresh air, the test panel could be safely retrieved.
• test panel displayed signs of surface skinning while the underlying regions remained quite wet. It was three - four hours before the test panel had a cure rate of 3-4 (see page 14. The control panel took some 8-10 hours to reach a similar cure rate. Comparative Example 2 In this experiment the two panels were sprayed with a one component white paint, which had been previously mixed with 0.5% w/w DMEA to catalyse the curing reaction. Again one panel was left as an air drying control while the second test panel was treated as follows:
• test panel was placed in a sealed chamber wherein was generated, by injection of carefully metered quantities of water to create an atmosphere with a Relative humidity level of 65% at a temperature of 25°C. This environment was recirculated at 1.5 m/sec for a period of 2 minutes after which a 3 minute purge cylce restored normal conditions and the test panel could be retrieved.
• test panel had experienced a slight increase in tack but it was 4 hours later before it had a cure rate of 3-4 (see page 14).
• the control panel took 6 hours to reach a similar cure rate and considerably longer to achieve resistance to solvent rub.
• MEK MEK
• the control panel was still quite wet at this point and even after a twenty four hour period could be dissolved by contact with MEK.
• Working Example 2 In this experiment the two standard paint panels were coated with the one component white, as supplied in its unmodified stable form. One panel was left to air dry as a control, while the second was tested as follows:
• test panel was placed in a sealed drying chamber, wherein was generated by injection simultaneously of carefully metered quantities of both TMEDA and water, an atmosphere containing 600 parts per million of TMEDA and a Relative humidity level of 65% at 25°c. This environment was then recirculated for 2 minutes after which a 3 minute purge cycle restored normal conditions to the chamber and the test panel was removed. The test panel was found to be fully cured at this point, and minutes later developed full resistance to contact with MEK. The control panel was quite wet and a check the next day revealed some dissolving with MEK.
• test panel was again found to be fully cured at this point and minutes later developed full resistance to contact with MEK.
• control panel was wet, and a check the next day revealed some dissolving with MEK.
• Graph III the horizontal scale indicates the Relative humidity as a percentage. For this graph, the impongement velocity was held at 1.4 metres per second, the temperature was kept at 25°C and DMEA was at a concentration of 1250 parts per million; and Graph IV: the horizontal scale indicates the impingement velocity, in metres per second.
• Table III which appears directly after Graphs II, III and IV, serves to demonstrate how the cure rate of a specifically chosen one component system is effected by those critical variables previously outlined.
• the invention provides a process for accelerating the polymerisation of isocyanate terminated prepolymers by facilitating the introduction of water into these systems by way of hydrated catalyst complexes in the vapour phase.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Paints Or Removers (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
• Polyurethanes Or Polyureas (AREA)
• Catalysts (AREA)

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Publications (2)

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• 1984
  • 1984-09-13 AU AU47164/85A patent/AU573381B2/en not_active Ceased
• 1985
  • 1985-09-03 IN IN726/DEL/85A patent/IN165343B/en unknown
  • 1985-09-04 ZA ZA856780A patent/ZA856780B/xx unknown
  • 1985-09-05 BR BR8507244A patent/BR8507244A/pt unknown
  • 1985-09-05 JP JP60504027A patent/JPS62501686A/ja active Pending
  • 1985-09-05 WO PCT/AU1985/000216 patent/WO1986001749A1/en not_active Application Discontinuation
  • 1985-09-05 IL IL76302A patent/IL76302A0/xx unknown
  • 1985-09-05 EP EP19850904408 patent/EP0194281A4/en not_active Ceased
  • 1985-09-06 YU YU01398/85A patent/YU139885A/xx unknown
  • 1985-09-09 GB GB08522285A patent/GB2166976B/en not_active Expired
  • 1985-09-10 PT PT81103A patent/PT81103B/pt not_active IP Right Cessation
  • 1985-09-10 CA CA000490288A patent/CA1263642A/en not_active Expired
  • 1985-09-11 DD DD85280520A patent/DD242622A5/de unknown
  • 1985-09-12 PL PL25534985A patent/PL255349A1/xx unknown
  • 1985-09-12 GR GR852225A patent/GR852225B/el unknown
  • 1985-09-13 ES ES85546949A patent/ES8609424A1/es not_active Expired
  • 1985-09-13 CS CS856551A patent/CS259883B2/cs unknown
  • 1985-09-13 CN CN85107196A patent/CN85107196B/zh not_active Expired
• 1986
  • 1986-05-01 KR KR860700241A patent/KR870700261A/ko not_active IP Right Cessation
  • 1986-05-13 FI FI861998A patent/FI861998A/fi not_active Application Discontinuation
  • 1986-05-13 NO NO861894A patent/NO861894L/no unknown
  • 1986-05-13 DK DK221286A patent/DK221286D0/da not_active Application Discontinuation

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