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
  • 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
  • B05D7/50—Multilayers
  • B05D7/52—Two layers
  • B05D7/54—No clear coat specified
• • 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
  • B05D7/14—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 metal, e.g. car bodies
  • B05D7/148—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 metal, e.g. car bodies using epoxy-polyolefin systems in mono- or multilayers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S138/00—Pipes and tubular conduits
  • Y10S138/06—Corrosion
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S138/00—Pipes and tubular conduits
  • Y10S138/07—Resins
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
  • Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
  • Y10T428/1355—Elemental metal containing [e.g., substrate, foil, film, coating, etc.]
  • Y10T428/1359—Three or more layers [continuous layer]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31511—Of epoxy ether
  • Y10T428/31515—As intermediate layer
  • Y10T428/31522—Next to metal
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31678—Of metal
  • Y10T428/31681—Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31678—Of metal
  • Y10T428/31692—Next to addition polymer from unsaturated monomers
  • Y10T428/31699—Ester, halide or nitrile of addition polymer

Definitions

• an adhesive is continuously applied to steel pipes before coating, in particular before heating; the tubes are then brought to the temperature required for melting the powdered plastic, then coated with the plastic in a fluidized bed process and then cooled. After the coating, a web of reinforcing material is applied to the still plastic plastic coating and embedded in the plastic.
• EP-A-26 906 has also already described a process for coating metal pipes by applying polyethylene powder to preheated pipes, first using a polyethylene with a melt index of 15 to 70, preferably 17 to 25 g / 10 min. on a metal tube, which has a temperature of at least 200 ° C, applies the coating to a temperature of about 110 to 170 ° C, preferably 110 to 120 ° C and then cool at this temperature in a third stage a self-supporting polyethylene film, for example a tape with a melt index of 0.1 to 7 g / 10 min. applies.
• the polyethylene powder adding an additional resin in the form of a polymer, for example polyvinyl acetate, ethylene-vinyl acetate copolymer, ethylene-acrylic acid and / or acrylic ester copolymer, if appropriate with further comonomers, or applying these polymers to the pipe before the polyethylene powder is applied, in both cases in a proportion of 2 to 5 wt .-%, based on polyethylene.
• the melting indices refer here and below to 190 ° C / 2.16 kg.
• Another known method provides for the coating of metal pipes by applying polyethylene to preheated pipes, initially using a polyethylene powder with a melt index of about 1.2 to 1.7 g / 10 min. or a strip emerging directly from an extruder with a melt index of at most 1.7 g / 10 min. on a metal pipe, which has a temperature of at least 300 ° C in the case of powder coating and a maximum of 250 ° C in the case of coating by the extruder, allows the coating to cool to a temperature of about 110 to 170 ° C and then at this temperature in the third stage a self-supporting, light-stabilized, light-colored polyethylene film with a melt index of 0.4 to 1.1 g / 10 min. applies.
• the aforementioned polymers can be mixed with the polyethylene or applied separately to the pipe.
• the present invention relates to a method for coating metallic substrates of the type defined in the claims.
• the method according to the invention makes it possible, for example, to produce coated pipes which can also withstand difficult installation conditions, for example transport over heavy or stony soils, without the coating being damaged.
• better, at least equally good adhesion as is known from the prior art, is achieved.
• the process is considerably simplified. It is no longer necessary to apply the adhesion promoter separately; rather, all the favorable properties of the coating are achieved by applying the powder mixture of the various components used according to the invention to the heated substrate.
• the final polyolefin layer which is firmly attached to the base layer, only serves for external protection.
• the metallic substrate is expediently preheated to a temperature of 200 to 360 ° C., preferably 240 to 310 ° C., before the first powder layer is applied.
• the heating temperature depends on the content of polyolefin in the powder mixture.
• the layer applied in the first stage generally has a thickness of 40 to 450, preferably 100 to 350, in particular 150 to 250 ⁇ m. A sufficient hardness, adhesive strength and temperature resistance of this layer is ensured by applying a layer of a curable resin A), copolymer B) and optionally polyolefin C). This layer can be applied, for example, electrostatically, by spraying under pressure (spray gun), by bulk sintering or in a trickle process.
• the proportion of component A) in the mixture is 10-45, preferably 15-35% by weight, based on components A) and B).
• the compounds required for curing the resins used are added to the mixture in customary amounts, but commercial resin-hardener mixtures are also sometimes used.
• the proportion of the hardener substances is contained in the quantitative data for component A).
• the epoxy resins are particularly preferred. Suitable are e.g. solid resins based on diphenylolpropane and / or diphenylolmethane and epihalohydrin such as epibromohydrin, but especially epichlorohydrin with an epoxy equivalent weight of 600 to 2000, preferably 700 to 1500, in particular 875 to 1100, optionally also a mixture of several epoxy resins.
• Possible hardeners for the epoxy resins are, for example: polycarboxylic anhydrides, polyamidoamines, secondary and tertiary amines, dicyandiamide and biguanide and substituted compounds derived therefrom, amine resins such as melamine resins, H examethylentetramin in combination with phenol resins of the T yp novolak resins, phenolic resins, COOH-functional polyester and acrylic resins, individually or in a mixture.
• Suitable curable polyesters are, for example, unsaturated polyesters with free OH groups, which are cured with polycarboxylic acids, their anhydrides and / or with - optionally blocked - polyisocyanates.
• curable acrylic resins e.g. Self-crosslinking etherified methoxylated resins based on acrylic and / or methacrylamides are suitable.
• Resins made from acrylic and / or methacrylic acid esters of polyhydric alcohols can also be used, which are cured with amines, especially amine resins or with polyisocyanates.
• Acrylic resins with built-in glycidyl groups which are hardened with polycarboxylic acid components are also suitable.
• the particle size of the resins A) in the powder mixture can vary widely. So epoxy resins with e.g. 0.2-300, preferably 1-100 ⁇ m are used; the size of the particles of the other resins A) is e.g. between 0.5 and 600, preferably between 1 and 300, in particular between 1 - 100 ⁇ m.
• Component B) of the powder mixture in which the term "vinyl compounds” includes (meth) acrylic derivatives, generally has and contains from 55 to 90, preferably from 65 to 85% by weight, based on components A) and B) as an essential constituent of at least one copolymer based on ethylene and (meth) acrylic acid and optionally at least one further copolymerizable monomer.
• copolymers which are free from (meth) acrylic acid can also be used.
• Copolymerizable monomers are, for example, vinyl acetate, (meth) acrylic acid esters with 1 to 18 carbon atoms in the alkyl radical and others.
• Component B) can have a different chemical composition have, the proportion of vinyl acetate in the copolymer can be completely or partially hydrolyzed to form the vinyl alcohol residue.
• It can, for example, a) a vinyl acetate-ethylene (meth) acrylic acid (meth) acrylic acid ester copolymer (melt index, for example, about 15-30 g / 10 min), b) a vinyl acetate-ethylene (meth) acrylic acid copolymer (Melt index, for example, about 20-35 g / 10 min), c) vinyl acetate-ethylene-vinyl alcohol copolymer (Schmelzindes, for example, about 55-75 g / 10 min), d) (meth) acrylic acid-ethylene copolymer with at least 85% by weight .-% ethylene (melt index, for example, about 5 to 80 g / 10 min.) Or e) (meth) acrylic ester (meth) acrylic acid-ethylene copolymer with at least 80% by
• the monomer content for the preparation of the copolymer can a) for example 5 to 10% by weight of vinyl acetate, 5 to 10% by weight of acrylic and / or methacrylic acid, 0.5 to 10% by weight of acrylic and / or methacrylic acid ester and at least 70% by weight of ethylene, the copolymer b) 0.5 to 10% by weight of vinyl acetate, 5 to 10% by weight of acrylic and / or methacrylic acid and at least 80% of ethylene, the copolymer c) 0.5 to 10% by weight of vinyl acetate, 5 to 25% of vinyl alcohol and at least 65% by weight of ethylene, of the copolymer d) 1 to 15% by weight of (meth) acrylic acid and at least 85% by weight of ethylene and the copolymer e ) 0.5 to 10 wt .-% (meth) acrylic acid, 0.5 to 10 wt .-% (meth) acrylic acid and at least 80 wt .-% ethylene.
• the ester group of the acrylic or methacrylic acid ester component is derived from monohydric alcohols with 1 to 18 carbon atoms.
• the copolymers of component B) are stabilized against the influence of heat.
• the particle size of the copolymers B) can be, for example, between 0.5 and 600, preferably between 1 and 200 ⁇ m.
• a polyolefin can be added as component C) to the mixture of the thermosetting resin A) and the copolymer B).
• Additives such as polyvinyl acetate, carbon black and heat stabilizers can also be added to component C).
• the proportion of component C) of the total mixture A) to C) 0 to 25, preferably 5 to 15% by weight, based on the sum of components A) and B).
• the additives contained in C) can total up to 10 wt .-%, based on C).
• the layer of olefin polymer applied in the second stage which can be approximately up to 6 mm, preferably 1.5 to 4 mm thick, serves to protect the base layer against injuries. It is expediently light-colored and can also be light-stable. It can e.g. as a powder or in the case of objects of suitable shape, in particular tubes, in the form of a tape with a thickness of 100 to 400 ⁇ m, preferably 150 to 250 ⁇ m, for example 0.2 mm in thickness.
• Suitable olefin polymers have e.g. a melt index of 0.3 to 25, preferably 0.5 to 20 g / 10 min. For example, it is made of polyethylene, e.g.
• polyethylene powder from the group LLD, LD (low density), HD (high density) or mixtures thereof, polypropylene or ethylene copolymers, e.g. those made from the same components as in the copolymers of the adhesive layer: the copolymers can also differ from those of the adhesive layer.
• LLD low density
• HD high density
• polypropylene or ethylene copolymers e.g. those made from the same components as in the copolymers of the adhesive layer: the copolymers can also differ from those of the adhesive layer.
• Suitable light stabilizers for the light-colored polyolefin film are compounds of the benzotriazole type, but also other compounds customary for stabilization. ,
• a light colored top layer has e.g. the advantage of good protection of the pipes against excessive heating when stored outside for long periods under the influence of heat, e.g. caused by sunlight or by laying in very warm soil layers.
• light colored olefin polymer material it is preferably white. However, a different color can also be selected, e.g. the warning color yellow, but also light orange, light blue, light green or the like. If necessary, the light-colored tapes can also be used to identify the pipes.
• the coating from the extruder is also very simple and time-saving without additional equipment.
• the strip emerging from the extruder advantageously has a melt index of at least 0.4 g / 10 min.
• the olefin polymer expediently has a particle size of 1 to in the powder coating in the second stage. 1600 microns, preferably 100 microns to 400 bar.
• a polyethylene film for example in pipe coating, is expediently applied in the form of a self-supporting polyethylene tape. It can be applied to a rotating tube. This has the advantage that the tape can be wound automatically.
• the bandwidth can be varied as desired. For example, it is at least 20 mm. A range of up to about 1 m is generally used.
• Resins A) are high charge carriers and move with appropriate acceleration, especially in the case of electrostatic coating, to the metal surface, where they melt immediately due to the high preheating temperature and crosslink immediately depending on the type and hardener additive. But even when sprayed with compressed air, the particles are charged by mutual friction.
• the preheating temperature should be so high that it is above the melting point of resin A ) and sufficient for crosslinking.
• the copolymers B) are largely prevented from the metal surface in this process.
• any polyolefir C) present In general, however, at least two zones are formed in which the individual components are enriched, with the presence of polyolefin C) further connecting the base layer to the olefin polymer applied in the second stage because the materials at the boundary layer are identical is improved. This is particularly true when polyolefin is applied as a sheet. A base layer is thus obtained which has individual zones with a predominant proportion of the individual components of the powder mixture.
• the olefin polymer e.g.
• Polyethylene as described, is carried out on the still hot, hardened or in the hardening process molten mixture, the substrate should have a temperature of at most 260 ° C when applying a polyolefin tape, while the temperature up to 360, preferably up to 300 ° C during powder application can be. This statement also applies to the application of the powder mixture A) to C) if it contains polyethylene.
• the substrate is cooled, e.g. in the air or by water cooling.
• the olefin polymer applied in the second process stage consists of an ethylene-vinyl acetate-acrylic or methacrylic acid copolymer
• the speed at which the coating is carried out can vary within wide limits. It depends on the layer thickness and the metallic substrate. For example, a tube with an outer diameter of 50 to 2000 mm has a minimum layer thickness between 1.5 and 4 mm for adequate corrosion protection conducive. For the coating of such a tube, which is normally 12 m in length and has a diameter of 1500 mm and a coating of 3.5 mm, the process according to the invention takes, for example, about 15 to 45, generally around 30 minutes. For the coating of a tube with a diameter of 400 mm and a layer thickness of 1.5 mm, a coating of 12 m in length generally takes about 8 to 20 minutes, for example 15 minutes.
• the requirements with regard to minimum layer thickness, freedom from pores, peel strength, impact resistance, indentation resistance, elongation at break, specific coating resistance, heat and light aging according to the regulations of DIN 30 670 and DIN 30 671 are fully met by the coatings produced according to the invention.
• the DIN 30 670 average force required for stripping the casing is 35 N / cm strip width.
• the metallic substrates coated by the process according to the invention which can consist of non-ferrous metals such as aluminum, copper, brass, bronze, zinc, but especially of iron or steel, are used in a variety of ways. It is preferably pipes which, because of their surface protection, are primarily used for pipes, e.g. for the extraction of petroleum, but also of other gaseous, liquid or highly viscous substances, for example natural gas. Water, sewage sludge, concrete, waste water, slurries or the like are suitable.
• a particular advantage is given by the fact that the pipes coated according to the invention have increased heat resistance, so that conveyed goods which have an elevated temperature, for example up to about 160 ° C., for example heated liquids, are conveyed over long periods of time without the coating being adversely affected can.
• the transport of heated liquids is necessary, for example, if the pipes are arranged behind compressor stations. In In these stations, the medium to be pumped is heated to temperatures of around 150 ° C, for example. In the subsequent pipe section there is therefore a thermal load which is between the ambient temperature and 150 ° C.
• metallic substrates other than pipes in which particularly resistant surface protection is important, can also be coated using the method according to the invention.
• large metal moldings, containers, components, etc. coated the list is not exhaustive and the process is appropriate to the circumstances, e.g. also an inner coating must be adapted.
• T means parts by weight and% by weight.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Laminated Bodies (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=6170399

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Country Status (4)

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• 1982
  • 1982-08-07 DE DE3229563A patent/DE3229563A1/de not_active Withdrawn
• 1983
  • 1983-08-02 EP EP83107590A patent/EP0100992A3/fr not_active Withdrawn
  • 1983-08-04 US US06/520,162 patent/US4481239A/en not_active Expired - Fee Related
  • 1983-08-05 CA CA000434027A patent/CA1205694A/fr not_active Expired

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