DE2214513A1 - Method and apparatus for coating plastic film - Google Patents

Description

PATHNTANWAL ^ TSBÜBO THOMSEN - TlEDTKE - B

ÜHLING

TEL. (0811) 530211 TELEX: 5-24 303 lopat

530212

PATENT LAWYERS Munich: Frankfurt / M .: Dlpl.-Chem. Dr. D. Thomson Dipl.-Ing. W. Weinkauff Dlpl.-Ing. H. Tiedtke (Fuchihohl 71)

Dipl.-Chem. G. Buehling Dipl.-Ing. R. Kinne Dipl.-Chem. Dr. U. Eggere

8000 Munich 2

Kaiser-Ludwlg-Platz6 March 24, 1972

22U513

Imperial Chemical Industries Limited
London, UK

Method and apparatus for coating plastic film

The invention relates to a method and a device for coating tubular art fabric films.

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It is often necessary or desirable to use tubular Plastic film to apply a coating, for example as a heat-weldable coating or as a barrier to serve for gases. It is often useful to apply the coating after the tubular film or Tubular film has been folded in flat form, with the coating either simultaneously on the two surfaces the lay-flat film web is applied or separately first on one side and then on the other. It was however found that conventional coating methods - for example, those in which the coating is in excess applied to the surface, then spread and finally the excess material by a doctor blade or the like Device is removed or where a continuous coating is applied directly by extrusion will - are unsatisfactory when used for coating a lay-flat tubular film. The reason the main reason for this is that the resilient property of the film completely collapses the tube prevented at the side folds and accordingly the applied coatings on and in the direction of the side folds are thinner than in the sections in or towards the center of the tubular film, i.e. away from the side gussets.

The invention provides a method by which substantially uniform coatings on tubular plastic

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- 3 films of fabric can be applied in flat form »

According to the invention there is a method for coating of tubular plastic film laid flat in it, that on the outer surface of a tubular film web a plurality of lines of the coating material softened in extrudable form extruded, these lines running parallel to the longitudinal direction of the tubular film and substantially are uniformly spaced across the width of the film surface and all with substantially the same Rate are deposited, and that then applied to this outer surface, a pressure that is sufficient to the deposited Spreading the coating materials and allowing them to merge into one another, thereby covering the outer surface and finally curing or allowing the resulting coating to cure.

The invention also provides an apparatus for coating tubular plastic films as characterized is through a plurality of nozzles, which are essentially at the same distance and through each of which a flowable Coating material can be extruded at substantially the same rate by means of advancement of the tubular film in the laid flat state in the longitudinal direction past the nozzles to pick up a multitude of lines of coating material running across the surface are distributed, and by a device for application

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_ ty -—: ■ '(. «

Apply a pressure on the surface that is sufficient for the deposited Spreading lines of coating material on the surface and allowing them to merge into one another.

A planar or flat shape to a collapsed tubular film has a Außenobe ^ f ^ <lllQirmit zwedrjSeiteiujr simultaneously öäer ^j isolated "with dTe ^ fi ^ can be coated bffchichtungsmaterial.

The inventive ^1; Ve "rli ^ -r% n sfcih Van den bek'arin4: en" method daViri "" that "the desired amount of coating material can be applied directly to the tubular film and is therefore zealous outer-Fiimöberfläcn ¥ n evenly "distributed" throw ^1. '"'

Im f öigQÄäe.iTiwirxfc a; preferred -Äusf Uhrtuvgs'form 'des Invention device treachery and the device according to the invention on an example; with reference-to the attached Zej.) cfein ^ B.g · eriljiiuitel ^ äi.e .sehematiaoh-schäUbildlich a

in action show * _- ■ <■ - ■■

Jes Fulvers

In de _; rji2fe ^ ohjHingu |> ezieä-chnet · the reference character 1 a

Bahn au-ö-Feia ^ üehfilm ^ in fiächterögter POrIn, 'die with the help

of a pair located downstream of the device rites forms; »

driven pinch rollers (not shown) is continuously moved further; the reference numeral 2 denotes an accumulator with a plurality of outlets, each of which is connected to a pipe 3

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^ -J b.

22H513

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small diameter are connected, these pipes

i £ n ^ nto are,

5 the

is reduced. The range of parameters allowed and it is her. Distance .with reference to the width of the

With the changes, aurcnxes are defined

jÖfiff ¹ M WnI ⁰ üeiEße ^p 5Shn-grams and day, a porosity of 60 ⁽ p when laying together. The pressure accumulator ^ 2 is made by a flexible

press aes powder with a pressure of about

7scpraä3ear ZnhÜiXfeaähme one

100 mA / cm at "room temperature for electrodes with

Pump can be adjusted to achieve the desired rate of deposition of Üjiner porosity of oO jo. ^B.

To obtain coating material on the tubular film web.

In the example given, the cathode passed and

the two counter electrodes made of graphite. In practice

. The Beßchich.tungsmairerial, is on. the train in, JEoKm but can the tn? apnitKatnocte be replaced aurtrn

a ^ nM ^^ ttlöÖtUe öionodftaraäJjslllfiahnatε abMg.-Applied «ir" l <£ i? ese

are made by zinc sheets or pieces of zinc, which are in a ¥ oW ^ & m ^ & k ^ iSfl & m MniÄnteÖfäifflPfte ^ W ^ t die die M ^ g ^ agAffixddin ^ TandaugeMfeäfticlWuÄg-slmä ^] ^^

to avoid. The electrolytic and let merge into each other also with solutions excluded

mOlexions. to avoid. Spread out the electrolytic path and allow it to merge into one another. However, separation can also be carried out with solutions

^The i ^h i ^t ii5 l ^k Afi ^^

will be the stoichiometric amount of cyanide, ghelate

The drawing shows the coating device for only one side of the tubular film. Of course, both can Sides of the web at the same time by a simple modification of the

2 0 928Q49 18 / AOi i ^ £ Ü97 5 8 ^{SAD 0RSG! NAL}

a mm Q mm

2213347

device shown are coated, for which a separate

for the second side of the

Railway is provided _r un, d following the ends of the coating tubes

Fig. 1 is the side view of a vertical: 5chnit-

above against the ba ^ ft, g * i £ iaö & 1 # J «öOSriJ $ e4e # eEhatte ^^ is of the same ^^ M & t ^ läcfe ⁵ ^

the elements involved in the process and the pipe that corresponds to the pipe 6 and that dur, ch the same

the connections to a reserve tank,

peristaltic Piirape ^ JsftftBieJPiPoiyf lefo ^ ßfchSPiilfÖi stratified path runs finally «^ <äfYHfi <ötfifcSÄ

will;
each of which is on one side of the film and with this in

Fig. 2 is a plan view of the device according to contact (one roller is the roller 10) to the lines

Fig. 1 to illustrate the arrangement and

from coating

broad and ina ^ e ^ bö ^ nift ¹ ^ 4ä & §ed ^en tffe ³

adhering cathodes into the container, preferably around each roller at an angle of wrap of about

is performed, together with a design

ι. r O

⁴⁰ · the distribution pipes that have a uniform

Layer flow of the electrolyte parallel

to the abutment surfaces of the cathode The tube (or tubes) 6, can be made of rubber or a

ensures and

consist of other elastically deformable material, preferably

Fig. Ί the schematic view of an electroae,

made of silicone rubber

The tubes 5 best ^^ Vb ^^ f ^ VMs ^ aui ^ Meiff ^ iybVr ^^ i ¹ material {

Carrier is formed after the particles

for this purpose, polytetrafluoroethylene is particularly suitable .

amalgamierx and purified. °

appropriate

· 10 galvanic system used to separate particles of a

will apply ^. to on the .surface of a, hose /.! Ims a

NetaXalloy can also be formed by precipitation

Apply coating of any flowable material, which is then solidified. The invention is particularly useful for applying coatings from solutions, emulsions or dispersions, as these are exposed to ambient

2 0 9 8 £ Q9 $$ l) £ 0 7 5 8 _fAD original

22U513

temperature can be applied and the coating through

Trocknßjx, can be solidified. . So, for example, can

Troae 4ö Can, like axes ϋβΐ3'ΰλΒΛ.Βνΐ ~ ι ^ β 5.η üg _; .->-.; ._-.- ■ -

become, w oil ·. «ι ύ-? ·? '.-- "* l'alJ / örägQi" ¹ "ίϋΐΐ§1 lür 3,1® ©;.;' --- v-Easy impermeable coatings are used. The process

trisohe u / fa iiiee-ianischö 7srbiiidang of the electrode jü., -,

that the coating material to a temperature above

The creation of a PuIts ^ s slixaz = To? ^ ßi ^ rnm ■ · ■■ · τ

its melting point is maintained until the coating material

amalgamated form allows the formation "tq & l '. ·? :: -

did and consequently of the great, available to us, Be adjusted for enamel coating, irrdenPman the pressure Surface for the electrochemical reaction.

Replaces constant volume pump and

keeps the tubes 5 at an elevated temperature for the

Me v.voreschrebenen measures, allow the Zubarr used Coating material is correct.

Zinc Alloy Electrode Pressing Mic One. .. sity of 60 Ms 75 f ° t without a filler wire,. .-:

or tti ^ lrSiSÄ ^ ufg ^ r ^ i ^^^ MecklMig ^^ drying through

by the size, the shape and the quantity to .. ■ Warming film supported, for example ~ by warm air currents

tert is made up by controlling the conditions

or dte & ve & BßttUa & ym & dk & k W ^^ i ^ m ^ kii ^^^ MlhrP ^^ ä ^ Wp ^{ei an}

Radiant heaters leads. If the coating is used as a

Older circuit for the electric. ^: ol / dfen .iBt schematise '· .- ^ melt melt is applied, the coating is allowed to cool or

shown with an electric motor 50, which is a ^

'^^ FMlMmf ¹ ^ MkWf ^{1 ddn} SflLtigkeWäläßiS Mjfßesit.i-Masst.

lytes can be controlled in such a way that there is a smooth ΕΙ-ϊα, -trolyte flow upwards along the Kathodenofoerfläöhsä gD ^ aa-j ^ coating process can be used for coating

tubular plastic film are applied before or after this is oriented by stretching, provided this

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is desirable. If the film is to be oriented, the coating is preferably applied beforehand, since the orientation generally produces a significant improvement in the adhesion of the coating to the film.

Plastic films obtained by the process according to the invention include those formed from, for example, linear polyesters such as polyethylene terephthalate, Polyolefins such as polyethylene, polypropylene and copolymers of ethylene or propylene with other olefins or others Comonomers, or polycarbonate resins.

The invention is illustrated below using an example in which the proportions are given by weight.

example

The coating process previously explained with reference to the drawing was applied to the two sides to coat a web of a tubular film made of polyethylene terephthalate. A latex made from vinylidene chloride / acrylonitrile mixed polymer (93: 7), which contained 45% by weight solids, was transferred from the reservoir 7 through two feed pipes 6 made of silicone rubber with an inner diameter of 1.587 mm, each running through the peristaltic pump 8, two pressure accumulators 2 fed. On the outlet side of each pressure accumulator there were seven pipes 5, each made of polytetrafluoroethylene and each had an inside diameter of 0.550 mm, against opposite sides of the traveling tubular film web

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held. The latex was laid down from the tubes in 7 parallel lines 6.35 mm apart and each 1.587 mm wide on each side of the web, the width of the tubular film when laid flat was 69 mm. The tubular film traveled at a speed of 30.5 m / min, and then went in a zigzag form around two spaced rollers which had a diameter of 2.54 cm and in the opposite direction with respect to the direction of travel of the film 1/5 of the film speed circulated, the wrap angle being 45 ° in each case. The parallel lines of the coating latex were flowed into one another by means of these rollers to form a uniform coating on each side of the web. The speed of the peristaltic pump was adjusted to give a coating thickness (wet state) of 0.00076 mm. Finally, the coating at a temperature of about 100 ⁰ C dried. A dry coating of highly uniform thickness was obtained on each side of the web.

The invention thus provides a method and an apparatus for coating tubular plastic films, by drawing a plurality of equally spaced lines on each surface of the laid sheet Applies coating material parallel to the length of the web and spreads the lines applied so that they become one uniform coating merge into one another.

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Claims (1)

Claims | 1 ·) Process for the coating of hose form! Plastic film in the collapsed state, characterized in that the outer surface of a tubular film web a plurality of lines of the coating material in softened, extrudable state so that the lines run parallel to the length of the tubular film and in the are substantially uniformly distributed across the width of the film surface and all at substantially the same rate are applied that you then apply a pressure on the outer surface which is sufficient to the deposited lines to spread out of coating material and so merge into one another to let them cover the outer surface and finally allowing the resulting coating to cure. 2. The method according to claim 1, characterized in that both sides of the outer surface are coated at the same time will. 3. The method according to any one of the preceding claims 1 and 2, characterized in that the lines of coating material be extruded from a large number of tubes, the free ends of which drag over the hose path. 209841/0809 22H513 - left - 4. The method according to any one of the preceding claims, characterized in that the applied lines of coating material with the aid of a circumferential in the opposite direction Roll are spread, which is in contact with the web. 5. The method according to any one of the preceding claims, characterized in that the coating as a solution, Emulsion or dispersion is applied. 6. The method according to claim 5, characterized in that the coated film for drying the coating is heated. 7. The method according to any one of the preceding claims 1 to <+, characterized in that the coating is applied as a melt. 8. The method according to claim 7, characterized in that that the melt-coated film is cooled by cooling the coated film with one or more Brings rollers into contact. ; 9. The method according to any one of the preceding claims, characterized in that the coating before or after is applied to orienting the tubular web. 209841/0809 22U513 -ίσ ιο. Apparatus for coating plastic film according to one of the preceding claims, characterized by a plurality of nozzles (3, 5) which are essentially at the same distance from one another and through which the flowable coating material is in each case extruded at essentially the same rate, through a device for the Advancing the tubular film in lay-flat form longitudinally past the nozzles to receive a plurality of lines of coating material spaced across the surface of the web and through means (10) for applying pressure to the web surface; which is sufficient to distribute the deposited lines from the coating material on the surface and to allow them to merge into one another. 11. The device according to claim 10, characterized by a plurality of nozzles for the extrusion of the coating material are arranged on both sides of a laid-flat tubular film. 12. Apparatus according to claim 10 and 11, characterized through a pressure accumulator (2) from which the coating material can be fed to the nozzles (3, 5). 13. The device according to claim 12, characterized by a peristaltic pump (8) for the delivery of the coating material to the pressure accumulator (2). 2 0 9 8 A1 / 0809 14. Device according to one of the preceding claims 10 to 13, characterized in that the device for the Applying a pressure consists of a roller (10) which rotates in opposite directions in contact with the film. 15. Device according to one of the preceding claims 10 to m, characterized by a device for solidifying the coating spread on the surface of the film. 16. The apparatus according to claim 15, characterized by means for heating the film. 209841/0809 Blank page