EP1502662A1 - A method of electrostatically coating plastic objects - Google Patents

A method of electrostatically coating plastic objects Download PDF

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Publication number
EP1502662A1
EP1502662A1 EP04466018A EP04466018A EP1502662A1 EP 1502662 A1 EP1502662 A1 EP 1502662A1 EP 04466018 A EP04466018 A EP 04466018A EP 04466018 A EP04466018 A EP 04466018A EP 1502662 A1 EP1502662 A1 EP 1502662A1
Authority
EP
European Patent Office
Prior art keywords
basecoat
application
born
plastics
paint
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP04466018A
Other languages
German (de)
English (en)
French (fr)
Inventor
Pavel Neuman
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.)
Peguform Bohemia AS
Original Assignee
Peguform Bohemia AS
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 Peguform Bohemia AS filed Critical Peguform Bohemia AS
Publication of EP1502662A1 publication Critical patent/EP1502662A1/en
Withdrawn legal-status Critical Current

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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
    • B05D7/56—Three layers or more
    • B05D7/57—Three layers or more the last layer being a clear coat
    • B05D7/577—Three layers or more the last layer being a clear coat some layers being coated "wet-on-wet", the others not
    • 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
    • B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
    • B05D1/04—Processes for applying liquids or other fluent materials performed by spraying involving the use of an electrostatic field
    • B05D1/045—Processes for applying liquids or other fluent materials performed by spraying involving the use of an electrostatic field on non-conductive substrates
    • 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
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D2201/00—Polymeric substrate or laminate
    • B05D2201/02—Polymeric substrate
    • 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
    • B05D7/56—Three layers or more
    • B05D7/57—Three layers or more the last layer being a clear coat
    • B05D7/574—Three layers or more the last layer being a clear coat at least some layers being let to dry at least partially before applying the next layer

Definitions

  • the invention relates to the method of applying the coating compositions on the surfaces of the plastics objects, or application of organic coatings on surface of the polymer substrate.
  • the plastics objects are not electrically conductive per se and because of their molecular nature adhesion of coating compositions to their surfaces is generally poor (mainly in case of polyolefin). For this reason the possibility to perform their quality coating is much more difficult compared to coating of the metallic objects. It is necessary to provide for enough strong linkage between polymeric substrate and applied coating. It can be achieved by suitable physical methods capable to partly break bonds of polymer macromolecules in a thin surface layer of the plastics object, e.g. by short flaming by a gas burner, whereby the polymer substrate surface molecules are impaired letting active molecular bonds arise able to bind themselves to the applied coating.
  • a primer is initially applied to the pre-treated plastics surface, which is a substance able to furthermore increase adhesion of the coatings successively applied onto the substrate and to ensure electrical conductivity of the surface.
  • the function of primer layer is to create the possibly strongest bond of the basecoat to the plastics surface and to enable the application of further coatings in electrostatic field, e.g. by electrostatic spraying.
  • the required coating is applied in one or more layers, consisting usually of more (most often two) different coating compositions having different properties and fulfilling different functions.
  • a basecoat which is matt after drying, is applied onto the primer, giving the plastics object the required final finish color and simultaneously ensuring the best possible adhesion of the following clear topcoat.
  • the basecoat paint is mostly a water-born one-component coating composition. Nevertheless, a solvent-born or a multi-component composition can also be used.
  • the glossy topcoat is applied, usually being clear and colorless, to fit any coloring of the basecoat.
  • This clear topcoat is mostly a solvent-born two-component composition, providing the highest gloss. Water-born clear topcoat can also be used, although it is more difficult to apply.
  • the clear topcoat layer creates the final finish of the plastic part and protects the underneath coating and the plastics object itself from weather effects and mechanical damage.
  • both pneumatic spraying and - which is more often - spraying in electrostatic field are used.
  • pneumatic application it is not necessary for the plastics surface to be conductive. Due to this fact the efficiency of the spray painting is relatively low, as substantial quantity of the paint misses the object not utilized, and it is necessary to liquidate it in an environmentally friendly way.
  • the efficiency of the electrostatic application is much higher, yet a conductive surface is required. In technical practice both methods are usually combined with the aim to obtain a reasonable compromise among technological capabilities, ecological requirements and economical interests.
  • the conductive primer is pneumatically applied on the non-conductive plastics object in the first stage. After this application, and even after drying, the surface remains electrically conductive and further coatings can be done by much more efficient electrostatic application.
  • each of the coatings - primer, basecoat and clear topcoat - is applied in separate spraying booth equipped with air-exhaustion to prevent mutual contamination of the applied coatings and to eliminate pollution of the surrounding ambience.
  • the surface of a plastics part, contaminated by dirt and especially by separator used in injection molds, is first of all thoroughly washed by detergents and pressure water and dried. After being washed the surface has to be pre-treated to activate the possibly best adhesion of the coat layers. This is done e.g. by short controlled flaming by a gas burner.
  • primer is applied by pneumatic or electrostatic application onto this freshly pre-treated surface.
  • Primer can be both water-born (which is in most cases) and solvent-born.
  • Primer layer can be applied in one spray or repeatedly, until the required total layer thickness has been reached. Usually the initial thinner layer is sprayed pneumatically and the next thicker one is applied electrostatically. Volatilizing, drying under increased temperature and cooling to ambient temperature follow.
  • the conductive primer has been applied, application of the basecoat onto thus prepared surface follows, being performed either in electrostatic or in pneumatic way.
  • the electrostatic application is used for the initial layers, while the pneumatic one usually for the final ones, particularly in case of metallic paints.
  • the basecoat paint can be applied in one spray or repeatedly to achieve required total thickness of the basecoat layer, that affects the final nuances of the respective color. Volatilizing, drying under higher temperature and cooling follow.
  • a non-conductive colorless clear topcoat is finally applied on the dry basecoat layer, the application being performed in the electrostatic way.
  • the clear and colorless topcoat can be applied in one spray or repeatedly, until the required layer thickness has been achieved. Volatilizing, drying under higher temperature and cooling to ambient temperature follow. After having passed the whole process the painted part is checked for quality and dispatched.
  • the target of the presented invention therefore is to reduce the demands regarding the paint shop technological equipment, to increase the productivity of the labor and to make the whole process more effective.
  • the target can be solved to a great extend by the method of applying the coating compositions on the surfaces of the plastics objects, by which the individual basecoat layers and the clear topcoat layers are applied either in electrostatic and/or in pneumatic way on the pre-treated surface of the plastics part until they reach the required thickness and color, both the basecoat application and the topcoat application being followed by volatilization, drying and cooling, according to the invention.
  • the principle of the invention consists in the fact that, prior to the application of the first basecoat layer, for which the standard water-born paint is used, a two-component base mixture, consisting of the respective standard water-born paint and a water-born adhesion and conductivity promoter, is applied onto the pre-treated plastics surface as undercoat, at least by one spray, in the first spraying booth, in which also the basecoat application follows. After the basecoat application is finished, a conductive clear topcoat is applied on the dry basecoat layer in the second spraying booth.
  • the principle of the method according to the invention consists further in the fact that the basecoat layers can be easily applied immediately after the application of the adhesive and conductive two-component base mixture in the same spraying booth, by spraying so to say "wet on wet".
  • the spraying booth routinely used for the primer application is eliminated now. Parameter setting of the application equipment remains the standard one.
  • the quantity of adhesion and conductivity promoter in the mixture with the water-born basecoat paint is highly variable.
  • the promoter quantity in the base mixture can directly control the efficiency of the application and thus the economic parameters of the painting process can be significantly optimized.
  • the two-component base mixture may - depending on the sort of the standard water-born paint, metallic or universal - contain from 1 up to 38 % of weight of the adhesion and conductivity promoter, which is based on binding and pigment agents and solvents, the rest is a water-born standard basecoat paint.
  • This reflects the ratio of the mixture components reaching as a maximum 60 weight parts of the promoter to 100 weight parts of the water-born basecoat paint.
  • Higher volume of the promoter increases the efficiency of the application even by 28 %, nevertheless, the basecoat layers of some paints require in such case application of higher thickness to reach the needed color.
  • a conductive clear topcoat (either water-born or solvent-born) with conductivity enhancing admixtures in the form of solvents, solvents for conductivity increase, hardeners and similar is applied, enabling thus solely electrostatic application instead of the former pneumatic one, provided the geometry of the part is suitable.
  • a conductive clear topcoat (either water-born or solvent-born) with conductivity enhancing admixtures in the form of solvents, solvents for conductivity increase, hardeners and similar is applied, enabling thus solely electrostatic application instead of the former pneumatic one, provided the geometry of the part is suitable.
  • the cleaned and washed surface of the plastics part in this case an automobile bumper, is pre-treated in the conventional way by short controlled flaming using natural gas burner, whereby physical condition for adhesion of the subsequently applied layers is improved.
  • the two-component base mixture containing 77 % of weight of metallic water-born standard basecoat paint and 23 % of weight of water-born conductivity and adhesion promoter is applied by electrostatic method on the pre-treated surface by one spray in the first spraying booth.
  • the promoter is a combination of binders with appropriate pigment and solvents, besides the usual organic solvents mainly water. In the described case the promoter is known under the commercial name Wörwag Haftzusatz A 1819.
  • electrostatic application of identical pure standard metallic basecoat paint follows in the same spraying booth immediately, no adhesion and no conductivity promoter being used in this case. If necessary, critical areas of the plastics part can be additionally treated by pneumatic application to reach the required thickness of the basecoat layer and proper color.
  • colorless conductive clear glossy topcoat mixture is applied by electrostatic way, by one spraying, in the second spraying booth.
  • This mixture contains 5 % of weight of special solvent to enhance the conductivity and 40 % of weight of standard solvent, to 100 weight parts of this mixture another 37 weight parts of hardener are added.
  • a very high efficiency of the application is achieved, being increased by 85 % compared to the application of a standard non-conductive clear topcoat.
  • critical areas of the plastics part can also be treated by additional pneumatic application to reach the required coat thickness. There is no difference whether this pneumatic application is done as the first step or as the last step when applying the topcoat. Then 10 minutes volatilizing under temperature of 25°C and relative humidity of 65 %, 50 minutes drying under 88°C, and finally 14 minutes cooling under 24°C follow.
  • the two-component base mixture containing 63 % of weight of universal water-born standard basecoat paint (no metallic) and 37 % of weight of water-born conductivity and adhesion promoter is applied by electrostatic way on the pre-treated surface, by one spray, in the first spraying booth. Then the application of identical pure standard universal basecoat paint follows in the same booth immediately. In this case two changes are obvious - the universal paint has replaced the metallic one and the content of the adhesion and conductivity promoter in the two-component mixture has been increased. With the exception of these changes the further procedure is identical with previous example.
  • the efficiency of the electrostatic application of the conductive clear topcoat in the second spraying booth is 75 % higher compared to the application of a standard non-conductive clear topcoat.
  • block 1 stands for surface treatment
  • block 2 represents the first spraying booth with the activity divided into two phases
  • 2a standing for the application of the two-component base mixture
  • 2b standing for the application of the pure standard basecoat
  • block 3 stands for volatilizing
  • block 4 for drying and block 5 for cooling
  • Block 6 follows representing the second spraying booth with electrostatic clear topcoat application
  • block 7 stands for volatilizing
  • block 8 for drying and block 9 for cooling.
  • the method described in the invention is in particular intended for the paint application onto the surface of the plastics components of automotive bodies, as e.g. bumpers, fenders, door panels, hoods and other exterior parts.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
EP04466018A 2003-07-28 2004-07-22 A method of electrostatically coating plastic objects Withdrawn EP1502662A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CZ20032055 2003-07-28
CZ20032055A CZ294230B6 (cs) 2003-07-28 2003-07-28 Způsob nanášení lakových vrstev na povrch plastových dílů

Publications (1)

Publication Number Publication Date
EP1502662A1 true EP1502662A1 (en) 2005-02-02

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP04466018A Withdrawn EP1502662A1 (en) 2003-07-28 2004-07-22 A method of electrostatically coating plastic objects

Country Status (2)

Country Link
EP (1) EP1502662A1 (cs)
CZ (1) CZ294230B6 (cs)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103624858A (zh) * 2013-12-13 2014-03-12 惠州市新金马家具制造有限公司 一种钢琴烤漆家具制作工艺
FR3008906A1 (fr) * 2013-07-25 2015-01-30 A C Ferm Procede pour le traitement de surface par laquage d'un element de fermeture, tel que fenetre ou porte, en matiere thermoplastique
CN116710747A (zh) * 2020-12-03 2023-09-05 西格马-奥尔德里奇有限责任公司 用于生物相容的固相微萃取装置的预涂层

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CZ303534B6 (cs) * 2011-09-26 2012-11-14 Magna Exteriors & Interiors (Bohemia) S.R.O. Zarízení k výrobe lakovaných produktu
CN111434441A (zh) * 2019-01-15 2020-07-21 广东长盈精密技术有限公司 金属外观件加工方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5120415A (en) * 1990-02-09 1992-06-09 E. I. Du Pont De Nemours And Company Method of improving the properties of coated reinforced thermoplastic articles and products obtained thereby
US5709909A (en) * 1993-03-19 1998-01-20 Basf Lacke & Farben, Ag Filler paste for use in basecoats for coating polyolfin substrates, basecoats, and process for the direct coating or polyolefin substrates
GB2359555A (en) * 2000-02-23 2001-08-29 Nippon Paint Co Ltd Electrically conductive coating composition

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5120415A (en) * 1990-02-09 1992-06-09 E. I. Du Pont De Nemours And Company Method of improving the properties of coated reinforced thermoplastic articles and products obtained thereby
US5709909A (en) * 1993-03-19 1998-01-20 Basf Lacke & Farben, Ag Filler paste for use in basecoats for coating polyolfin substrates, basecoats, and process for the direct coating or polyolefin substrates
GB2359555A (en) * 2000-02-23 2001-08-29 Nippon Paint Co Ltd Electrically conductive coating composition

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3008906A1 (fr) * 2013-07-25 2015-01-30 A C Ferm Procede pour le traitement de surface par laquage d'un element de fermeture, tel que fenetre ou porte, en matiere thermoplastique
CN103624858A (zh) * 2013-12-13 2014-03-12 惠州市新金马家具制造有限公司 一种钢琴烤漆家具制作工艺
CN103624858B (zh) * 2013-12-13 2016-02-10 惠州市新金马家具制造有限公司 一种钢琴烤漆家具制作工艺
CN116710747A (zh) * 2020-12-03 2023-09-05 西格马-奥尔德里奇有限责任公司 用于生物相容的固相微萃取装置的预涂层

Also Published As

Publication number Publication date
CZ20032055A3 (cs) 2004-10-13
CZ294230B6 (cs) 2004-10-13

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