DE3500814A1 - MARKING PROCEDURE - Google Patents

Description

^ÄDS398 3 35008 HC *

description

The invention relates to a method for marking Fluoropolymer articles. This method is used to color code these items. The procedure is special useful for marking wires coated with a fluoropolymer.

It is difficult to mark fluoropolymer items since pigments do not adhere well to fluoropolymer surfaces; it is therefore desirable to find new, pigment-containing compositions that adhere well to fluoropolymer surfaces.

The inventive method is a method for Marking a fluoropolymer surface by application a composition on this surface, wherein the composition is a dispersion of an organic Liquid with a surface tension below 40 dynes / cm,

measured at 25 ⁰ C, contains the %

a) 5-95% by weight of at least one copolymer 50-90% by weight of tetrafluoroethylene units and 5-50% by weight of hexafluoropropylene units, with a molecular weight of more than 20,000,

b) 5-95% by weight of at least one epoxy compound and

c) 1-25% by weight pigment

has, and then drying the marked surface.

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Ad 5398 / j

35008H

In a preferred embodiment of the invention the dispersion composition is applied to an elongated fluoropolymer body, such as a fluoropolymer insulation coating on a wire, like copper wire, while the body is on a dispersion applicator moved past.

An organic dispersion containing components (a) and (b) defined above constitutes a system for adhering pigments to fluoropolymer surfaces to disposal. The organic liquid has a surface tension below 40 dynes / cm at 25 ° C and can be an aromatic hydrocarbon such as benzene or toluene, a ketone such as methyl isobutyl ketone Medium gasoline with a boiling range of 94 to 175 ° C, naphtha or a chlorinated hydrocarbon and the like be.

The copolymer preferably contains 75-95% by weight of tetrafluoroethylene units and 5-25% by weight of hexafluoropropylene units.

The epoxy compound can be the diglycidyl ether of bisphenol Be a. Known crosslinking agents such as melamine formaldehyde or benzoguanamine formaldehyde can be used will. The pigment can be any conventional pigment which is dispersible in the dispersion, such as Red 2B, carbon black, phthalocyanine green or blue, molybdenum orange, alizarin brown, titanium dioxide, chrome yellow and the like.

The dispersion can be prepared by combining all of the ingredients except for the pigment, as described in US Pat. No. 3,661,831. and then stirring in the pigment.

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When used, the dispersion is simply applied to the surface of a fluoropolymer article that can be marked, taped, or color-coded target. The dispersion is particularly useful for making elongated fluoropoly animal bodies, such as fluoropolymer coatings on electrical wires, to be provided with a band-shaped marking. There are different possibilities, to do this; this includes application by means of a cushion brush, roller or spray nozzle.

The fluoropolymer surface can be made from any fluoropolymer resin be made, e.g. from tetrafluoroethylene horopolymers or from copolymers of tetrafluoroethylene and at least one fluorinated, ethically unsaturated comonomer copolymerizable therewith.

Examples of copolymerizable, fluorinated, ethylenic unsaturated comonomers are those of the general form in:

Cl Η _χ

\ C ~ CF ₂ , C = CF ₂ or C = CH ₂ ,

R ₁ FR ₂

wherein R _{1 is} -Rf, -RfX, -O-Rf, or -O-RfX, wherein -Rf is a perfluoroalkyl radical having 1-12 carbon atoms, -Rf- is a linear perfluoroalkylene radical having 1-12 carbon atoms, in which the free bonds are at the ends of the linear chain, and XH or Cl; and wherein R _{2 is} -Rf or -RfX.

Exemplary comonomers are hexafluoropropylene, perfluorohexene-1, Perfluorononen-1, Perfiuor- (methyl vinyl ether), Perfluoro (n-propyl vinyl ether), perfluoro

i. AD 5398. £ ■ 350081 Λ

(n-heptyl-vinyl-ether), perfluoromethyl-ethylene, perfluorobutyi-ethylene, ω -Hydroperf luorpenten-1,3-Hydroperfluor- (propyi-vinyl-ether) and mixtures thereof, such as a mixture of hexafluoropropylene and perfluoro (propyl vinyl ether).

The copolymerizable, fluorinated, ethylenically unsaturated comomer is preferably selected from the group of perfluoro (alkyl vinyl ethers) of the formula Rf-O-CF = CF ₂ , where Rf is an alkyl group with 1-5 carbon atoms, or the perfluorinated, Terminally unsaturated olefins of the formula Rf-CF = CF ₂ , in which Rf is an alkyl group with 1-5 ^w carbon atoms, or the perfluoroalkylethylenes with 3-7 carbon atoms of the formula Rf-CH = CE ₂ , in which Rf is an alkyl group with 1 -5 carbon atoms.

The comonomer content in the TFE copolymers can be from 0.005 mole percent up to about 20 mole percent, with more than 1 comonomer being present. Accordingly, the TFE comonomers can be both melt processable % TFE copolymers and melt non-processable TFE copolymers. The comonomer content is so low that the copolymers are not elastomers but plastics, ie they are partially crystalline and after extrusion do not show a rapid return to the original length from the 2X stretched state at room temperature. For example, if a perfluorinated olefin is the comonomer, the content can preferably be 0.02-20 mol%, and if a perfluoroalkylethylene is the comonomer, the comonomer content can preferably be between 0.02-7 mol%. If the comonomer is a perfluoro (alkyl vinyl ether), the comonomer content is preferably between 0.02-2.3 mol%. The copolymer tends towards the lower part of these ranges

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usually in addition, not processable in the melt while in the upper part of these ranges the copolymer normally tends to be melt processable to be.

The articles are made by sintering method, melt extrusion method depending on the type of fluoropolymer or paste extrusion processes.

Example;

A tape marking of wire was carried out by the dispersion composition was pumped through two oscillating, opposed nozzles that did not were directly aligned. The oscillating movement caused the dispersion in a serpentine pattern raft. The period of oscillation determined the distance between each band. The first nozzle supplied the first half of the belt, the second nozzle was synchronized in such a way that that she completed the tape.

The tape marker was downstream but near the Extruder, which was used to coat the wire with fluoropolymer resin, arranged. That was the heat of the resin cures the dispersion composition and thus achieves excellent adhesion, without the use of an inline arranged post heater was required.

In this application the dispersion composition passed the end:

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1. methyl isobutyl ketone solvent mixture,

2. Tetrafiuoräthylen / Hexafluorpropyiencopolymer (85/15), with a molecular weight over 20,000,

3. diglycidyl ether of bis-phenol A,

4. Soot, added in a carrier material

5. a vinyl resin,

6. Ketone / alcohol extender

7. Benzoguanamine-Formaldehyde.

Component 6 was about 44% by weight of the dispersion, while components 1-5 were about 56%. The carbon black and vinyl resin base "were about 1.8% and 4%, respectively. Component 1 was present in an amount of about 27%, component 2 in about 12-13%, component 3 in an amount of about 8-9%, and component 7 of about 2.%

The fluoropolymer coating was a copolymer of tetrafluoroethylene and hexafluoropropylene (85/15). A copper wire was covered with it.

Anilox rollers or offset rollers can be used.

Anilox rollers are generally used for identification used by regular surfaces. The reel usually has symbols embossed on its circumference and runs through a belt of dispersion. Excess dispersion is then passed off the roller a scraper removed and the dispersion in the wells then transferred to the wire insulated with fluoropolymer resin.

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An offset roller is used for irregular surfaces. The principle is the same as with the anilox roller, except that the offset roller removes the marking from the anilox roller and then applies it to the wire surface transmits.

Claims (3)

Patent Attorneys European Patent Attorneys W. Abitz 35008 14 D.F. Morf- D l) | fh Abitz. Morf. Gritschnulcr. by Wiitucnstein. P.O. Box 86 (Il IW. XIHH) Munich Sn Dr. l) i | i |. fhcm. ! M. Gritschneder Dipl.-I'lm. A. Frhr. von Wittgenstein Or. Dipl .- ("hem. Postal address / Postal Address Postfach 86 01 (WD - 8 (XM) Munich 86 January 11, 1985 AD 5398 EI DU PONT DE NEMOURS AND COMPANY Wilmington, Delaware, V.St.A. Marking method claims 1. method of marking fluoropolymer articles; characterized by providing a fluoropolymer surface by applying a composition marked, which is a dispersion of an organic * Liquid with a surface tension below 40 dynes / cm, measured at 25 ° C, contains the Munich - Bogenhausen Phone: 5 23 - 1 -
Telex: Fax (II & III - automat. ): Telegram: Poschingerstraße 6 (089) 98 32 22 992 {abitz el) (089) 98 40 37 Cheniindus Munich a) 5-95% by weight of at least one copolymer 50-90% by weight of tetrafluoroethylene units and 5-50% by weight of hexafluoropropylene units, with a molecular weight of more than 20,000, b) 5-95% by weight of at least one epoxy compound and a crosslinking agent for these and c) 1-25% by weight pigment has, and then the marked surface dries. 2. The method according to claim 1, characterized in that that the dispersion is applied to an elongated fluoropolymer body. 3. The method according to claim 2, characterized in that ^ That the elongated fluoropolymer body has a coating / is on a wire or cable.