AU652880B2 - Polyolefin tanks internally coated with moisture hardening coating compositions and a process for their preparation - Google Patents

Polyolefin tanks internally coated with moisture hardening coating compositions and a process for their preparation Download PDF

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Publication number
AU652880B2
AU652880B2 AU31123/93A AU3112393A AU652880B2 AU 652880 B2 AU652880 B2 AU 652880B2 AU 31123/93 A AU31123/93 A AU 31123/93A AU 3112393 A AU3112393 A AU 3112393A AU 652880 B2 AU652880 B2 AU 652880B2
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AU
Australia
Prior art keywords
weight
coating
coating composition
polyolefin plastic
tank
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Ceased
Application number
AU31123/93A
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AU3112393A (en
Inventor
Wolfgang Henning
Michael Hense
Werner Kubitza
Rolf Rummel
Franz-Ferdinand Zollner
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Carl Diederichs & Co GmbH
Bayer AG
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Diederichs Carl & Co KG
Bayer AG
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Publication of AU3112393A publication Critical patent/AU3112393A/en
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
    • C09D175/04—Polyurethanes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
    • B60K15/03—Fuel tanks
    • B60K15/03177—Fuel tanks made of non-metallic material, e.g. plastics, or of a combination of non-metallic and metallic material
    • 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
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/02—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to macromolecular substances, e.g. rubber
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B1/00—Layered products having a non-planar shape
    • 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
    • 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
    • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
    • C08G18/78—Nitrogen
    • C08G18/7806—Nitrogen containing -N-C=0 groups
    • C08G18/7818—Nitrogen containing -N-C=0 groups containing ureum or ureum derivative groups
    • C08G18/7831—Nitrogen containing -N-C=0 groups containing ureum or ureum derivative groups containing biuret groups
    • 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
    • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
    • C08G18/78—Nitrogen
    • C08G18/7806—Nitrogen containing -N-C=0 groups
    • C08G18/7818—Nitrogen containing -N-C=0 groups containing ureum or ureum derivative groups
    • C08G18/7837—Nitrogen containing -N-C=0 groups containing ureum or ureum derivative groups containing allophanate groups
    • 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
    • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
    • C08G18/78—Nitrogen
    • C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
    • 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
    • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
    • C08G18/78—Nitrogen
    • C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
    • C08G18/791—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing isocyanurate groups
    • C08G18/792—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing isocyanurate groups formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates
    • 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
    • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
    • C08G18/78—Nitrogen
    • C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
    • C08G18/798—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing urethdione groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
    • C08J7/04—Coating
    • C08J7/0427—Coating with only one layer of a composition containing a polymer binder
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
    • C08J7/04—Coating
    • C08J7/043—Improving the adhesiveness of the coatings per se, e.g. forming primers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
    • C09D175/02—Polyureas
    • 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
    • C08G2390/00—Containers
    • C08G2390/40—Inner coatings for containers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2475/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Materials Engineering (AREA)
  • Paints Or Removers (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Polyurethanes Or Polyureas (AREA)
  • Cooling, Air Intake And Gas Exhaust, And Fuel Tank Arrangements In Propulsion Units (AREA)
  • Details Of Rigid Or Semi-Rigid Containers (AREA)
  • Wrappers (AREA)
  • Laminated Bodies (AREA)

Description

Our Ref: 453930 P/00/011 652 8 Regulation 3:2
AUSTRALIA
Patents Act 1990
ORIGINAL
COMPLETE SPECIFICATION STANDARD PATENT 0. 00 e Applicant(s): Bayer Aktiengesellschaft D-5090 Leverkusen Bayerwerk
GERMANY
Carl Diederichs Co GmbH
DUSSELDORF
GE1'MANY Address for Service: Invention Title: DAVIES COLLISON CAVE Patent Trade Mark Attorneys Level 10, 10 Barrack Street SYDNEY NSW 2000 Polyolefin tanks internally coated with moisture hardening coating compositions and a process for their preparation The following statement is a full description of this invention, including the best method of performing it known to me:- 5020 Mo-3831 LeA 28,854-US POLYOLEFIN TANKS INTERNALLY COATED WITH MOISTURE HARDENING COATING COMPOSITIONS AND A PROCESS FOR THEIR PREPARATION BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a process for coating the inside of polyolefin plastic tanks, in particular fuel tanks, with moisture-hardening coating compositions based on organic O polyisocyanates and to the resulting coated polyolefin plastic tanks.
Description of the Prior Art The use of polyolefin plastics for the production of fuel tanks is known. It is also known that such fuel containers require a surface treatment on the interior of the wall for 15 producing extreme imperviousness, for preventing diffusion of the fuel to the outside. Treatment of the surface with fluorine or fluorine compounds has the effect of a diffusion barrier, but also has the disadvantage of not being sufficiently environmentally friendly because the emission of hydrogen fluoride takes place when the synthetic resin is 20 thermally recycled.
This disadvantage can be overcome by coating the internal surfaces of tanks with halogen-free coating compositions.
However, this alternative is also not satisfactory because 1) \conventional coating compositions emit noxious substances since they contain organic solvents and 2) the bond strength of o conventional organic coatings on polyolefin surfaces is not sufficient when the surfaces are continuously subjected to the action of fuels, even if the surfaces have been pretreated, by corona discharge, plasma irradiation, etc.
35052TWR811 LeA 28 854-US -2- It has now been surprisingly found that the moisturehardening, solvent-free coating compositions according to the invention, which are described in detail below and contain certain polyisocyanates which are liquid at room temperature, are eminently suitable for coating the inside of polyolefin plastic tanks used for liquid hydrocarbons, in particular fuels. These coatings retain the necessary bonding strength even when permanently subjected to such hydrocarbons. They Salso provide the necessary resistance to hydrocarbons and, thus, prevent permeation of the liquid hydrocarbons, in particular fuels, to the outside.
This observation is also surprising in view of the teachings of DE-OS 2,845,514 since according to the this publication it is necessary to use mixtures of lacquer 15 polyisocyanates with certain monoisocyanates as binders for solvent-free, one-component polyurethane coating compositions.
In addition, this publication does not suggest the suitability ::oo of the mixtures described therein for coating the inside of tanks made of polyolefin hydrocarbons.
In a similar manner the teachings of EPA 0,085,309 relate to coating PVC substrates, and not to coating the inside of hydrocarbon tanks made of polyolefin plastics. Accordingly, S this publication does not suggest the solution of the problem solved by the present invention. The coating of comparatively polar PVC surfaces does not allow any conclusions to be drawn to the possibility of coating comparatively apolar polyolefin surfaces which are known to be difficult to coat.
SUMMARY OF THE INVENTION The present invention relates to a process for coating the inside of a polyolefin plastic tank for storing liquid hydrocarbons by I) coating the inside of the tank with a moisture-hardening, coating composition having a viscosity at 23°C of 60 to 2,500 mPa.s and containing Mo3831 a) at least one polyisocyanate having average polyisocyanate functionality of greater than 2 and containing biuret, isocyanurate, uretdione and/or allophanate groups which is liquid at room temperature, is prepared from hexamethylene diisocyanate and has an isocyanate content of at least by weight and a free hexamethylene diisocyanate content of less than by weight, and b) 0 to 5% by weight, based on the weight of the coating composition, of an organic solvent for polyisocyanates which is inert towards isocyanate groups and II) curing the coating under the influence of moisture.
1o The present invention also relates the resulting coated polyolefin plastic tanks for storing liquid hydrocarbons, in particular gasoline or diesel fuel.
DETAILED DESCRIPTION OF THE INVENTION The coating compositions to be used according to the invention have a viscosity at 23*C of 60 to 2,500 mPa.s, preferably 100 to 1000 mPa.s. Since the coating compositions to be used according to the invention are preferably solvent-free systems, polyisocyanate component a) also preferably conforms to these viscosity requirements.
Component a) is selected from "lacquer polyisocyanates," in particular allophanate, (ii) biuret, (iii) isocyanurate or (iv) isocyanurate and uretdione group containing polyisocyanates, which are prepared from "a hexamethylene diisocyanate. Mixtures of these polyisocyanates 25 may also be used. The polyisocyanates have an average isocyanate functionality of greater than 2, preferably 2.1 to 6 i and more preferably 2.5 to 4; an isocyanate content of at least by weight, preferably 20 to 25% by weight; and a free hexamethylene diisocyanate content of less than 0.5% by weight.
30 The polyisocyanates a) are prepared in known manner by the reaction of hexamethylene diisocyanate to introduce biuret groups, allophanate groups, isocyanurate groups or both isocyanurate and uretdione groups. Any excess hexamethylene diisocyanate present after the reaction is removed in known manner, preferably by distillation, so that the free hexamethylene diisocyanate content is less than 0.5% by weight.
The preparation of polyisocyanates containing b t groups may be carried out in known manner using biuretizing agents such as tert.-butanol or by the reaction of hexamethylene diisocyanate with subequivalent quantities of hexamethylene diamine to form biuret.
The preparation of polyisocyanates containing allophanate groups may be carried out by the reaction of hexamethylene diisocyanate with simple alcohols such as methanol, ethanol, propanol, butanol, etc.. The reaction proceeds through an intermediate where the polyisocyanates contain urethane groups which are then converted to allophanate groups.
The preparation of polyisocyanates containing isocyanurate is groups is carried out in known manner using suitable trimerization catalysts such as quaternary ammonium bases.
S"The preparation of polyisocyanates containing isocyanurate Sand uretdione groups is carried out in known manner by the oligomerization of hexamethylene diisocyanate in the presence of phosphine catalysts.
The lacquer polyisocyanates which are most preferably used as component a) are polyisocyanate containing both isocyanurate and uretdione groups, wherein the molar ratio of isocyanurate groups to uretdione groups is preferably from 80:20 to 20:80.
25 These polyisocyanates have a viscosity at 23°C of 100 to 1,000 mPa.s.
The coating compositions to be used according to the invention may, if necessary, contain small quantities of isocyanate-inert solvents b) to adjust the viscosity, preferably from 0 to 5% by weight thereof, based on the weight of the coating composition. Examples of these solvents include n-butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, 2-methoxypropyl acetate, toluene, xylene and mixtures of these solvents. However, the coating compositions to be used according to the invention are preferably solvent-free systems.
Mo3831 The coating compositions to be used according to the invention may optionally contain inert auxiliary agents and additives such as those conventionally used in coating composition formulations, in particular those based on polyisocyanates. Examples of these auxiliary agents and additives include levelling agents, defoamants, catalysts for the isocyanate-water reaction (in particular known organic tin compounds, dibutyl tin dilaurate) and'plasticizer oils Sand resins which increase the elasticity. If desired or necessary, the coating compositions may also contain known fillers or pigments, optionally together with known pigment drying agents.
The plastics tanks which are to be internally coated in accordance with the present invention are tanks prepared from a. 15 polyolefin plastics, in particular polymers and copolymers of ethylene, propylene and/or the isomeric butenes, which may optionally contain small quantities of monomers having functional groups, such as acrylic or methacrylic acid, incorporated by polymerization. It is particularly preferred according to the invention to use substrates prepared from ethylene-butene copolymers, for example, Vestolen AX 4013, 1 available from Huls AG.
Before the internal coating is applied, a suitable pretreatment of the internal walls of the tank may be carried 25 out to optimize adhesion of the coatings according to the invention. Suitable pretreatment processes include corona discharge and, preferably, plasma irradiation.
The coating compositions to be used according to the invention may be applied by conventional methods but for the use according to the invention application by the centrifugal method is particularly preferred. In this process, a certain quantity of the coating composition is introduced into the tank and set in motion by a centrifugal movement so that every point on the internal surface becomes completely wetted. In order to ensure that areas of the internal surface of the tank which are Mo3831 more difficult to reach will also be wetted, sources of infra-red irradiation may be applied to the outside of these areas so that the viscosity of the coating agent is lowered and the flowability improved. A similar effect may also be produced by means of ultrasound.
The coating compositions to be used according to the invention are stable in storage when atmospheric moisture is excluded and are hardened by moisture to form tough elastic e films or coatings. The moisture required for the reaction may be available as atmospheric moisture, but the necessary moisture may also be introduced artificially as steam, in continuous processing plants.
The coating compositions to be used according to the invention are generally introduced in quantities resulting in 15 wet film thicknesses of 40 to 100 pm.
The coatings are preferably be cured at room temperature, but curing may also be accelerated by applying elevated temperatures such as, for example, 100 to 180 0 C. In this case, it is advisable to supply steam to increase the reaction velocity (drying and curing).
The invention is further illustrated but is not intended to be limited by the following examples in which all parts and percentages are by weight unless otherwise specified.
EXAMPLES
The following polyisocyanates are used in the examples: Polvisocvanate A A biuret polyisocyanate primarily containing tris-(isocyanatohexyl)-biuret and prepared by the biuretization of hexamethylene diisocyanate according to US-PS 3 903 127 followed by the removal of excess hexamethylenediisocyanate by distillation.
NCO content: 23.5% by weight.
Free hexamethylene diisocyanate content: by weight Average isocyanate functionality: >3 Viscosity: 2400 mPa.s/23"C.
Mo3831 Polvisocvanate B A polyisocyanate mixture primarily containing tris-(isocyanatohexyl)-isocyanurate and bis-(isocyanatohexyl)-dretdione which was prepared by the phosphine-catalyzed oligomerization of hexamethylene diisocyanate followed by the removal of excess hexamethylene diisocyanate by distillation.
NCO content: 22.0% by weight Free hexamethylene diisocyanate content: 0.5% by weight Average NCO functionality: 2.7 Viscosity: 200 mPa.s/23"C.
Example 1 37.7 parts by weight of polyisocyanate A, 37.7 parts by weight of polyisocyanate B and 3.5 parts by weight of a commercial pigment drying agent, tolyl sulphonyl S 15 monoisocyanate (Additive TI, available from Bayer AG, Leverkusen) were homogeneously stirred, using a stirrer with a
S
mixing disc.
0.4 parts by weight of a commercial silica derivative (Aerosil 972, Degussa AG, Frankfurt) and 19.8 parts by weight of a commercial talc were then stirred in.
To wet the inorganic components, the speed of rotation of the mixing disc was increased to 10-15 m/sec and rotation was S"continued at this speed for about 10 to 20 minutes. The reaction mixture was then cooled to room temperature and parts by weight of a commercial defoamant (Byk 351 of Byk in Wesel) were added with slow stirring together with 0.4 parts by weight of dibutyl tin dilaurate as catalyst. A storage stable, moisture hardening, one-component coating composition was obtained.
Mo3831 For test purposes, test plates of Vestolen AX 4013 plastic which had been pretreated by plasma irradiation were coated with the coating composition to provide wet film thicknesses of to 100 im. At room temperature and 50% relative humidity, the films were dust-dry after 2 h and dry to the touch after h. Their adherence to the pretreated substrate was very good. No change could be detected after several days' storage in super grade gasoline.
Example 2 Example 1 was repeated with the exception that only polyisocyanate B was used as component Due to the lower viscosity of polyisocyanate B, the viscosity of the whole formulation was reduced. The time required to reach dust-dryness of the applied films was increased to 3-4 hours 15 because of the lower reactivity of polyisocyanate B and the time for complete drying dry to the touch) was increased to about 6 hours.
•Adherence to the polyolefin plastic was very good.
Permeation of fuel through the coated polyolefin plastic was only 0.15 to 0.25% of the amount which permeated through a corresponding uncoated plastic surface.
iL' Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
Mo3831

Claims (9)

1. A process for coating the inside of a polyolefin plastic tank for storing liquid hydrocarbons which comprises I) coating the inside of said tank with a moisture-hardening, coating composition having a viscosity at 23°C of 60 to
2.500 mPa.s and comprising a) at least one polyisocyanate having average polyisocyanate functionality of greater than 2 and containing biuret, isocyanurate, uretdione and/or allophanate groups which is liquid at room temperature, is prepared from hexamethylene diisocyanate and has an isocyanate content of at least by weight and a free hexamethylene diisocyanate content of less than by weight, and b) 0 to 5% by weight, based on the weight of the coating composition, of an organic solvent for polyiso- cyanates which is inert towards isocyanate groups and II) curing the coating under the influence of moisture. 2. The process of Claim 1 wherein said polyolefin plastic tank is a fuel tank.
3. The process of Claim 1 wherein the coating composition has a viscosity at 23'C of 100 to 1,000 mPa.s.
4. The process of Claim 2 wherein the coating composition has a viscosity at 23'C of 100 to 1,000 mPa.s.
A polyolefin plastic tank for storing liquid hydrocarbons wherein the interior of the tank is coated with a moisture-hardening, coating composition having a viscosity at 25 23'C of 60 to 2,500 mPa.s and comprising a) at least one polyisocyanate having average polyisocyanate functionality of greater than 2 and containing biuret, isocyanurate, uretdione and/or allophanate groups which is liquid at room temperature, is prepared from 30 hexamethylene diisocyanate and has an isocyanate content of at least by weight and a free hexamethylene diisocyanate content of less than by weight, and b) 0 to 5% by weight, based on the weight of the coating composition, of an organic solvent for polyisocyanates which is inert towards isocyanate groups.
6. The polyolefin plastic tank of Claim 5 wherein said ,L polyolefin plastic tank is a fuel tank. *i 4 f 4
7. The polyolefin plastic tank of Claim 5 wherein the coating composition has a viscosity at 23"C of 100 to 1,000 mPa.s.
8. The polyolefin plastic tank of Claim 6 wherein the coating composition has a viscosity at 23°C of 100 to 1,000 mPa.s.
9. A coating composition or a process for coating the inside of a polyolefin plastic tank or a polyolefin plastic tank having an internal coating substantially as hereinbefore described with reference to the Examples. DATED this 8th day of January 1993, 15 BAYER AKTIENGESELLCHAFT 15 S" and CARL DIEDERICHS *CO. GMBH By Their Patent Attorney DAVIES COLLISON CAVE f *UU Mo3831 Mo-3831 LeA 28,854 POLYOLEFIN TANKS INTERNALLY COATED WITH MOISTURE HARDENING COATING COMPOSITIONS AND A PROCESS FOR THEIR PREPARATION ABSTRACT OF THE DISCLOSURE The present invention relates to a process for coating the inside of a polyolefin plastic tank for storing liquid hydrocarbons by I) coating the inside of the tank with a moisture-hardening, coating composition having a viscosity at 23*C of 60 to 2.500 mPa.s and containing a) at least one polyisocyanate containing biuret, isocyanurate, uretdione and/or allophanate groups which is liquid at room temperature, is prepared from hexamethylene diisocyanate and has an isocyanate content of at least 10% by weight and b) 0 to 5% by weight, based on the weight of the coating composition, of an organic solvent for polyiso- cyanates v..ch is inert towards isocyanate groups and II) curing the coating under the influence of moisture. The present invention also relates the resulting coated polyolefin plastic tanks for storing liquid hydrocarbons, in W particular gasoline or diesel fuel. o* r
AU31123/93A 1992-01-16 1993-01-08 Polyolefin tanks internally coated with moisture hardening coating compositions and a process for their preparation Ceased AU652880B2 (en)

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DE4200906 1992-01-16
DE4200906A DE4200906A1 (en) 1992-01-16 1992-01-16 USE OF MOISTURIZING VARNISHES BASED ON ORGANIC POLYISOCYANATE FOR THE INTERNAL COATING OF PLASTIC TANKS

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AU652880B2 true AU652880B2 (en) 1994-09-08

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KR (1) KR100232067B1 (en)
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CA (1) CA2087284A1 (en)
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DE4206747A1 (en) * 1992-03-04 1993-09-09 Huels Chemische Werke Ag PLASTIC HOLLOW BODY WITH REDUCED PERMANENTNESS
US5461135A (en) * 1994-09-23 1995-10-24 Olin Corporation Polyisocyanates containing uretidione and allophanate groups, a process for their production, and their use in one and two component coating compositions
DE4437050A1 (en) * 1994-10-17 1996-04-18 Leybold Ag Device for treating surfaces of hollow bodies, in particular inner surfaces of fuel tanks
DE19754456C2 (en) * 1997-12-08 2001-03-29 Plastic Omnium Gmbh Barrier layer composition for plastic bodies and their use
CZ20033520A3 (en) * 2001-05-25 2004-05-12 Superfosápackagingáa@S Container of cover made of thermoplastic material and thermoplastic material treatment process
DE10303596A1 (en) * 2003-01-30 2004-08-12 Volkswagen Ag Plastic fuel container manufacture involves assembling functional components in the container wall before application of polymer barrier layer
ATE430040T1 (en) * 2005-10-27 2009-05-15 Emballator Lagan Plast Aktiebo METHOD FOR PRODUCING A COMPONENT OF A PACKAGING AND THE DESIGNED COMPONENTS
ES2388267B1 (en) * 2011-03-29 2013-09-02 Montajes Maga S L RECONVERSION OF SINGLE WALL TANK TO DOUBLE CONTAINER TANK.
MX2018008944A (en) * 2016-01-21 2018-11-09 Basf Coatings Gmbh Radiation-curable coating agent, method for creating scratch-resistant coatings, use of the coating agent, and substrate coated with a coating agent.
JP2020023664A (en) * 2018-08-07 2020-02-13 旭化成株式会社 Polyisocyanate composition, coating composition and coating film

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DE3202166A1 (en) * 1982-01-23 1983-08-04 Bayer Ag, 5090 Leverkusen USE OF CLEAR VARNISHES BASED ON ORGANIC POLYISOCYANATES FOR THE COATING OF SURFACES BASED ON POLYVINYL CHLORIDE
NL8401942A (en) * 1984-06-19 1986-01-16 Stamicarbon PROCESS FOR REDUCING THE PERMISSIBILITY OF POLYALK COATINGS FOR HYDROCARBONS.
DE3435992A1 (en) * 1984-10-01 1986-04-10 Hüls AG, 4370 Marl Fuel container made of polyethylene with reduced permeability

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JPH0798917B2 (en) 1995-10-25
CA2087284A1 (en) 1993-07-17
AU3112393A (en) 1993-07-22
EP0551819A1 (en) 1993-07-21
EP0551819B1 (en) 1995-12-06
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JPH0680929A (en) 1994-03-22
KR100232067B1 (en) 1999-12-01
MX9300106A (en) 1994-07-29

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