FR2558167A1 - FLUOROPOLYMER OBJECT MARKING METHOD - Google Patents

Abstract

THE INVENTION RELATES TO THE MARKING OF OBJECTS. IT CONCERNS A PROCESS FOR MARKING OBJECTS IN FLUOROPOLYMER, CHARACTERIZED IN THAT THE SURFACE IS MARKED BY DEPOSITING A COMPOSITION THEREIN WHICH IS A DISPERSION IN AN ORGANIC LIQUID HAVING A SURFACE TENSION LESS THAN 40DYNESCM, MEASURED AT 25C, CONTAINING .5 TO 95 BY WEIGHT OF AT LEAST ONE COPOLYMER OF 50 TO 90 BY WEIGHT OF TETRAFLUOROETHYLENE UNITS AND FROM 5 TO 50 BY WEIGHT OF HEXAFLUOROPROPYLENE UNITS, HAVING A MOLECULAR WEIGHT GREATER THAN 20,000; B.5 TO 95 BY WEIGHT OF AT LEAST ONE EPOXIDE COMPOUND; C.1 TO 25 BY PIGMENT WEIGHT, AFTER THE MARKED SURFACE IS DRYED. USE ESPECIALLY FOR MARKING METAL WIRES BEARING AN INSULATING COATING IN FLUOROPOLYMER.

Description

BACKGROUND OF THE INVENTION The invention relates to a method of marking

  of fluoropolymer objects for the coding of objects by color. The method is especially useful for marking fluoropolymer coated wire. It is difficult to mark fluoropolymer objects because the pigments do not adhere well to fluoropolymer surfaces and so it is desirable

  to provide new compositions containing pig-

  which adhere well to fluoropolymer surfaces.

  Definition of the invention The method of the invention is a method of marking a fluoropolymer surface by depositing, on the surface, a composition which is a dispersion in an organic liquid having a surface tension of less than 4C dynes / cm, measured at 25 ° C., containing: (a) 5 to 95% by weight of at least one copolymer of 50 to 90% by weight of tetrafluoroethylene units and 5 to 50% by weight of

  hexafluoropropylene units, having a molecular weight of

  greater than 20,000, (b) 5 to 95% by weight of at least one 4-oxide compound, (c) 25% by weight of pigment,

  after which the marked surface is dried.

  In a preferred aspect, the composition will be deposited on an elongate fluoropolymer body, such as a fluoropolymer which forms an insulating coating on a wire such as a copper wire, as the body passes an applicator. dispersion,

Description of the invention

  It has been discovered that an organic dispersion containing components (a) and (b) as defined above constitutes a system for adhering a pigment to fluoropolymer surfaces. The organic liquid has a surface tension of less than 40 dynes / cm at 25 ° C and can be an aromatic hydrocarbon such as

  benzene or toluene, a ketone such as methyl-

  isobutyl ketone, mineral spirits, naphtha or

  chlorinated hydrocarbon, and the like.

  The copolymer is preferably one of those in which the tetrafluoroethylene units are present

  at 75 to 95% by weight and the hexafluoro-

  propylene in a proportion of 5 to 25% by weight.

  The epoxidized compound may be diglycidyl ether of bis-phenol. Common crosslinking agents such as melamine / formaldehyde may be used.

or benzoguanamine / formaldehyde.

  The pigment may be any common pigment

  persistant in the dispersion, such as Red 2B, carbon black green or phthalocyanine blue, molybdenum orange, alizarin brown, TiO2, chrome yellow,

and the like.

  The dispersion can be prepared by combining all the ingredients except the pigment, as described in U.S. Patent 3,661,831, and then incorporating the pigment with stirring. For use, the dispersion is simply applied to the surface of a fluoropolymer article to mark, zebra, color code, etc. Dispersion is particularly useful for marking bodies

  elongated fluoropolymers such as fluoro coatings

  ropolymer on an electric wire. There are several ways to do this, which include applying by means of a

  brush, wheel or spray.

  The fluoropolymer surface may be formed of any fluoropolymer resin. It may be a homopolymer of tetrafluoroethylene or copolymers of tetrafluoroethylene and at least one fluorinated comonomer

  copolymerizable with ethylenic unsaturation.

  Representative copolymerizable fluoronomeric ethylenically unsaturated comonomers include those of the formulas:

FC. H

FI- .. CCF C = CF-2 and C = eH

- 21 2 C = CH2

/ 2

R1 F R2

  in which R 1 is -Rf, -RfX, -O-Rf or -O-RfX, where Rf is a perfluoroalkyl radical of 1 to 12 carbon atoms, -Rf is a linear perfluoroalkylene radical of 1 to 12 carbon atoms in which the bonding valences are at each end of the linear chain, and X is H or C1; and R2 is Rf or -RfX. Representative comonomers include hexafluoropropylene, -1

  perfluorohexene-1, perfluorononen W, perfluoro-

  (methyl vinyl ether), perfluoro- (n-propyl vinyl ether), perfluoro- (n-heptyl ether)

  and vinyl), perfluoromethyl-ethylene, perfluoro-

  butyl-ethylene, W-hydroperfluoropentene-1, 3-hydroxy-

  perfluoro- (propyl vinyl oxide) and the like,

  or mixtures thereof such as a mixture of hexafluoro-

  propylene and perfluoro- (propyl vinyl oxide).

  The fluorinated comonomer copolymerizable with

  The ethylenic acid is preferably chosen from perfluoroalkoxides of the formula Rf-O-CF = CF 2 in which Rf is an alkyl group of 1 to 4 carbon atoms, or terminal-unsaturated perfluoroolefins of the formula Rf-CF = CF2 in which Rf is a

  alkyl group of 1 to 5 carbon atoms; or perfluoro

  wherein Rf is an alkyl group of 1 to 4 carbon atoms of the formula Rf-CH = CH2. The comonomer content of the TFE copolymers can vary from 0.005 mole% to about 20 mole%, and

  there may be more than one comonomer. Thus, the copoly-

  TFE mothers include both TFE copolymers

  can be processed in the molten state and copoly-

  TFE mothers can not be processed in the molten state. The comonomer content is low enough that the copolymers are rather plastics

  than elastomers, that is, they are partially

  crystals and after extrusion, they do not show a rapid retraction to the original length in

  from an elongated state of 2X at room temperature.

  For example, when the comonomer is a perfluoroolefin

  The content may be preferably from 0.02 to 20 mol%, and when the comonomer is a perfluoroalkyl ethylene, the comonomer content may preferably be from 0.02 to 7 mol%. When the comonomer is a perfluoro- (alkyl vinyl oxide), the comonomer content may preferably be from 0.02 to 2.3 mol%. At levels

  of these ranges, the copolymer normally tends to

  not be able to be processed in the molten state,

  say that at the top of these ranges, the copolymer tends

  normally able to be processed in the molten state.

  Depending on the type of fluoropolymer, objects are made by sintering, extrusion

  the molten state, or extrusion of paste.

EXAMPLE

  In one application, we performed the

  striping of a wire by pumping the

  dispersion through two opposing oscillating nozzles

  which are not directly aligned. Movement

  oscillation caused the dispersion to flow into a

  snake. The oscillation period determines the

  between the bands. The first nozzle provided the first half of the band and the second nozzle was

  synchronized to complete the band.

  The strip marker was placed downstream of the extruder which was used to cover the fluoropolymer resin wire, but near it. This allowed the heat of the resin to harden the dispersion compositions, ensuring excellent adhesion without the need for heating devices.

further online.

  In this application, the composition of the dispersion was as follows: 1) mixture of methyl isobutyl ketone as solvent 2) tetrafluoroethylene / hexafluoropropylene copolymer (85/15) with a molecular weight greater than 20,000, 3) diglycidyl ether of phenol A 4) carbon black, added in a vehicle of) vinyl resin 6) a ketone / alcohol diluent

7) benzoguanamine / formaldehyde.

  Component 6) constituted about 44% by weight of the dispersion while components 1) to) constituted about 56%. The carbon black and the vinyl resin carrier constituted about 1.8 and 4% respectively. Constituent 1) was present

  approximately 27%, component 2) of about 12 to 13%,

  3) of about 8 to 9% and component 7) of about 2%

  The fluoropolymer coating was a copoly

  tetrafluoroethylene and hexafluoropropylene

  (85/15). It was applied on copper wire.

  We can use engraving wheels or

  rubber transfer rollers.

  Engraving wheels are usually used to identify regular surfaces. The wheel generally has recessed symbols at its circumference and is passed through a bath of the dispersions. The excess dispersion is then removed from the wheel by means of a doctor blade and the dispersion is transferred.

  in the hollows on the wire insulated by fluoride resin

  polymer. A rubber transfer wheel is used for irregular surfaces. The principle is the same as for the engraving wheel except that the rubber transfer wheel receives the mark of the wheel of

  engraving and then transfers it to the surface of the wire.

2558167,

Claims (3)

  1. Method of marking fluoropodic objects   lymere, characterized in that the surface is marked by depositing thereon a composition which is a dispersion in an organic liquid having a surface tension of less than 40 dynes / cm, measured at 25 ° C, containing: (a) 5 to 95 % by weight of at least one copolymer of 50% by weight of tetrafluoroethylene units and 5% by weight of hexafluoropropylene units, having a molecular weight greater than 20,000, (b) 5 to 95% by weight of at least one epoxidized compound, (c) 25% by weight of pigment,   after which we dry the marked surface.   2. Method according to claim 1, characterized   rised by the fact that the dispersion is deposited on a elongated body of fluoropolymer.   3. Process according to claim 2, characterized   in that the elongated fluoropolymer body is   a coating on a wire or cable.