DE1694808A1 - Process for the production of moiekuiar oriented polyester films coated with an adhesive layer - Google Patents

Description

PATENT LAWYERS · · - "

DR ₁ -ING-VONKREiSLSR DR.-ING. SCHÖNWALD 1 69480-8

or. p

COLOGNE 1, DEiCHMANNHAUS

Cologne, January 2nd, 1968

-Mr / Br en

. .- ... ■■ - ·, -.- Applicant in: ". ..."

EGG. du Pont de Nemours & Company "- · 'Wilmington ..... Delaware. 1.9 898

"■■ · ■ ·". ■ p ·· ''"' ^r - ^ - -.- ^ United States of America"' ^N '

Process for the production of molecularly oriented polyester films coated with an adhesive layer

"The invention relates to a method of manufacture of polyester films coated with an adhesive interlayer. "" \

Made from polyesters such as polyethylene terephthalate, photographic film supports have relatively hydrophobic / surfaces and do not adhere well to those hydrophilic, photosensitive layers containing gelatin or; other • natural. Or synthetic, water-permeable, organic, contain colloidal binders. Since the poly -.-, ester whether it is relatively chemically resistant, | will she not by the usual solvents for the insensitive Layer solved. ' Therefore 'becomes a - mechanical marriage There is no connection between the layer and the film base easily achieved. To overcome this' difficulty, a coating is placed on the surface of the support. Usually applied from a synthetic, organic copolymer, this resin layer then serves as a Binder to anchor a hydrophilic layer on the support.

009842 / 18-5-2 bad original

Ξ, ξ is known ;, a resin layer on a polyester carrier to apply in two-stage working method, in which first stage the cast beam for the purpose of biaxial orientation before. Apply an aqueous emulsion to the Seeken "vvird. The second stage is the application of an adhesive layer made of gelatine on the stretched base, (YgI, USA patents 2 627 088 and 2 698 255). This adhesive layer system requires the application of a synthetic material organic mixed polymers "existing layer before the rear process Film carrier prevents. because the simultaneous presence of Ilischpolymeren affects the recovery of Reject product. In addition, it is desirable to find a '/ experienced in which the polyester base in connection with the keck process with the. Adhesive layer is provided, · ■ -um in that the synthetic resin substrate does not suffer any unnecessary "abrasion" when it passes through the rollers.

The object of the present invention is the application of a synthetic, organic copolymer on a polyester silicone backing based on an aqueous dispersion of the mixed polymer after the cast.! film carrier has been stretched and heat-treated to achieve dimensional stability. -... · .-.

The invention is based on a method for producing a biaxially oriented polyester film coated with an adhesive layer, the surface of which has been pretreated. As characteristic is considered that, to the e pretreated film surface with an aqueous dispersion coated, the 1 to 15: ~ wt% of a mixed polymer Removing at least _■;.. "Contains two ethylenically unsaturated monomers .., of which" one "is an aliphatic ·, unsaturated carboxylic acid-, where ·, the transition temperature of the second order of the copolymer is between -30 ° and +30 ⁰ O, after which one den -beschAoliteiieii .; film dries, especially "at temperatures aisohea 60 wsxu. 100 ° ö ι and the mixed polymer on the PolyeateKfilth: ziam J && m ~ γ -

hard at least 7 sec .. on tempex ^ atures between 120 to 180 ° ö heated.

The copolymers which can preferably be used according to the process according to the invention include the following:

l.) 'A copolymer of (a) 70 to 90% by weight of an unsaturated ester of a monocarboxylic acid, the alcohol component of the ester containing no more than, A carbon atoms j (b) about 7 to 20 Qevi.- fp an,! aliphatic polyfunctional compound which contains at least two unsaturated molecular components, at least one of these components being represented by an allyl or vinyl group, by glycidyl acrylate, glycidyl methacrylate or by a methacrylic acid ester, the alcohol component of which is substituted by a hydroxyl group is, 'or by fumaric acid and (c) about 3 to JO% by weight of an unsaturated acid from the series itaconic acid, fumaric acid, acrylic acid or methacrylic acid, where, if (b) fumaric acid (c) is itaconic acid.

2.) A copolymer from (a) about 70 to 90 parts by weight "Vinyl acetate, (b) about 7 to 40 parts by weight of a lower Alkyl acrylate and (c) about 3 to JO parts by weight of an unsaturated Acid from the series itaconic acid, fumaric acid. Acrylic acid or methacrylic acid.

X 3) A blended polymer of (a) 70 to 95 wt .-% methyl or ethyl acrylate, (b) 3 to 30 wt -.? ·% Diallyl phthalate or divinylbenzene, and (c) 2 to 20 wt .- o Itaeonsäure.

But also other mixed polymers, e.g. those in the IFSA- * patents 2,627,088, 2,69.8,235, etc. can be used.

The film carrier used in accordance with the invention can consist of any suitable polyester consist »e.g. of polyethylene terephthalate, Polyethylene terephthalate / isophthalate according to the British

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U.S. Patent 766,290 and films described in U.S. Patent $ "052 543". The polyester films can Pigments or dyes or various matting agents, such as egg el acid particles. Particularly those according to US Pat. No. 2,779,684 by polyester formation from a dicarboxylic acid and a are suitable dihydric alcohol-made films.

The pretreatment of the film surface is carried out according to known methods. The following have proven to be useful, for example: (l) The effect of electrical! ¹ discharges, with the electrodes being charged by a high-voltage generator at 10,000 V, 1.4 amps and 1100 watts (cf. USA Patent 3 "112 208); (2) the action of a flame generated by the combustion of air / propane ( see U ^ A file transcript "-3 145 242). Other treatment methods for increasing the adhesion can be used, such as treating the surface with peroxides together with liatrium peroxides, with chromic acid in sulfuric acid and with oxygen or ozone in the presence of ultraviolet light.

After the film has been appropriately prepared, i.e. biaxially oriented and made dimensionally stable by heat treatment, a coating of a synthetic, organic mixed polymer layer is applied in the form of an aqueous dispersion. The liquid portion of this aqueous dispersion can consist of 90 to 100% water, but up to 10 % other liquid additives, such as alcohols, are permissible. Good to excellent anchoring was obtained when the preferred terpolymer used was (l) an unsaturated ester, namely either betayl acrylate, ethyl acrylate, vinyl acetate or η-butyl acrylate, (2) a bifunctional compound: and (3) either itaconic acid or fumaric acid contained. The main component of the polymer in the system should expediently have a transition temperature of the second "order, ie the temperature at which the component changes from the amorphous to the crystalline state.

in the range from -30 to + '' K) ⁰ .

"9 8 4 2/1852 BAD ORIGINAL

It has been found that the unsaturated acid in the polymer enmolekül is required for good anchoring. the bifunctional compound serves to make the polymeric molecule to make them insoluble in water, which in turn increases the degree of adhesion · The bifunctional monomer in the preferred polymer also serves as a crosslinking agent. These compounds have the purpose of depositing the polymer insoluble in the solvent, and ensuring dimensional stability of the resulting latex and increase the molecular weight.

The adhesive layer can be applied to the. Carrier web according to known / experienced applied vrerdeii, e.g. by application with wiping off, by extrusion coating or application using co-rotating rollers.

.uacri the coating should be the film at temperatures of preferably 60 to 100 ° are dried.

The film coming out of the dryer can be heat treated and cured immediately. The heat treatment serves two purposes: firstly, it relaxes the substrate and secondly, it hardens the coating. The oriented polyester film, which is coated with a copolymer, is heated to a temperature between 120 and 180 ° for at least 7 seconds.

It has been found that the adhesion preliminary of the copolymer in the aqueous solution is directly related to the curing temperature. If the parameters of the thermal relaxation with regard to time and temperature are related to one another, the following general results are obtained: An increase in the curing time without changing the other conditions leads to improved anchoring. The same result also resulted in an increase in the hardening temperature to 120 to 180 °.

BADORlGtNAU _ ₆ _

009842/1852

The proportion of solids in the copolymer resin is closely related to the extent of anchoring. With the "preferred Working methods give a low solids content sufficient anchoring, while a high solids content good Anchoring results. The aqueous dispersion can be 1 to 15 λ>, preferably 2.5 to 10%, mixed polymer contain.

Should the film be combined with a photographic emulsion containing formaldehyde, precautions should be taken to protect the adhesive layer from resin protect, as formaldehyde tends to destroy the anchorage ζμ. It is therefore advisable to use a protective gelatin layer to be applied to the film to enhance the effect of fox-maldehyde cancel or reduce. In the process of manufacture of such films, the gelatin layer is expediently after a pretreatment of the surface, e.g. electrostatic discharge can be caused on the Biaxially stretched base is applied and then the synthetic, organic copolymer adhesive layer is applied.

The advantage of the present invention is to be seen in the fact that a synthetic, organic copolymer adhesive layer can be applied to a hydrophobic polyester substrate after the substrate has been cast and stretched. This makes it possible, if desired, to carry out the casting and stretching process in one operation and the coating in another. Furthermore, rejects that arise during casting and stretching can be reused without additional process steps. Another advantage is that the heat treatment following the stretching, if carried out separately from the hardening of the copolymer, makes it possible to maintain the desired properties of the polyester film without having to forego proper hardening of the copolymer.

To improve the adhesion »Ohromkcaplex«, wit »ie • pielaweiee in dta USA patent * ol) .rift «n 2 544 66? uad 2 §49

'2/1 * 6 2'

are described, the Beschichtuiigsmaaseii are added.

The usual sensitometric "exposed and developed" films described above were performed Tests showed that none of the interpolymers tested adversely affected the photographic properties of the film. "

The invention is illustrated in more detail by the following examples. Share and percentages relate in each case on weight.

example 1

Zv: Polyethylene terephthalate films were cast and at about 88 ° 0 to three times the original longitude and latitude stretched, with film thicknesses set iron 0.1 and 0.18 mm became; The films were then fixed in accordance with Example 1 of US Pat. No. 2,779,684. One followed Surface treatment according to USA patent 3 113 2C8. The electrodes were connected to a high voltage generator charged at 1.4 amps, 1100 watts and 10,000 tonnes.

100 parts of methyl acrylate (not inhibited), 10 parts of diallyl malonate, 6 parts of itaconic acid, 5 parts of a 30% strength sodium lauryl sulfate solution and 300 parts of water are mixed with one another to obtain a copolymer. The mixture was about 15 minutes under nitrogen Bu ^ chleiten stirred, increasing the temperature to 75 ° 0 and 0.5 feile ammonium persulfate! Dissolved in 10 parts water was added. The slightly milky-white colored solution immediately became translucent while the temperature rose to 80 °. The reaction temperature was maintained for 1 hour between 70 and 80 °, wherein a müchig-white kreiclear1> strength Substans was incurred, the mt with distilled water to a substance F was diluted concentration of 3%. D <,. s copolymers had a transition temperature of the second order between 0 and 5 °

009842/1852 BAD ORIGINAL ~ ⁸ ~

The resulting aqueous dispersion became one side coated a biaxially oriented polyethylene terephthalate film, the coating with wiping off with . done with a squeegee; '' Temperature of the polymer coating compound: 35 ° C. The coated film was then 2 min. At 1530 ° C relaxed. A gelatin-silver halide emulsion was then applied to the surface coated with the polymer layer applied for lithographic purposes, each containing 82 mg of silver halide 52 mg of gelatin (30 mol .-% AgBr and 70 mol .- ^ AgCl), also hardening-inhibiting substances, 2j4-dihydroxybenzaldehyde and polyhydroxybenzene corresponding to U.S. Patent 2,591,54-2. -

The films had excellent tack strength when wet, as demonstrated by exposing samples to hot light, developing and fixing them in a standard hydroquinone-paraformaldehyde-type lithographic developer solution, after washing but before drying at etxtfa Turn 70 ° with a playback needle zx ^ ei 5 »! 1 cm long lines were scratched through the emulsion layer at a distance of 1.3 cm and rubbed over these marks with a rubber stick. The coatings did not tend to peel off the documents. The test of the adhesive strength in the dry state was carried out by exposing a sample of the film coated as above to white light and further treating it as described. Four parallel lines were then scratched into the dried sample with the aid of a playing needle at a distance of 0.6 cm. A group of lines was then drawn through these lines at an angle of 60 degrees, with a distance of jex to 0.6 cm being maintained. In this way 9 rh erb al three figures were carved into the emulsion layer woz'deii. A piece of pressure-sensitive adhesive tape made of regenerated cellulose was pressed onto the area provided with incised lines, the loose end of the cover was grasped and untex * at an angle of 90 ° ₌₎ based on the area of the obex. In this way an arbitrary measure of the adhesive strength could be kept, if in each case a group of

00 9 £ 42/1852

BftD

694808

10 samples with a series of St and ardprob s known adhesive strength was compared, the adhesion strength between "excellent ¹¹ and""'have." Excellent "is in the" very low · iTergleichsskala by the number 0, very low due to the' ΔθΙιΙ 5. In general, an excellent adhesive strength was determined in the dry state.

Examples 2 to 10:

The emulsion for Eöntgen ~ z-.iecke used in these examples was a gelatin / silver iodobromide emulsion which, as described below, had been digested and prepared for coating. The emulsion containing 1.2 Mol Yes SilberJödid and 98.8 mol .-% silver bromide and the procedure described in US Patent 3 06 838 ^ G-Elatine Dextr-to-binder. The ratio of binder to silver halide was 1.1: 1. The emulsion suitable for lithographic purposes and used in the examples corresponded to that of example 1. ■

The following copolymers were used in the examples applied:

A) A mixed polymer of methyl acrylate / allyl acrylate and itaconic acid, produced according to the example

B) A mixed polymer of methyl acrylate / diallylsebazate (14 files) und_Itaconic acid, manufacture accordingly Example 1.

G) A copolymer of, diallyl phthalate, methyl

acrylate and itaconic acid in a mixture with a Ghromciiloridkomplex of methacrylic acid according to German patent application P 40 990 IXa / 57 b.

Each of the copolymers A »B and G had a transition temperature second Ordixang between ö and 5 ° ö ·

009342, '

'Blackboard

■ j ^ί! · Ro; ⁵ .el surface pretreatment watt / 2, ^ 4 cm "

Width / 30, 48 mpm

Type of

Mixed polymer layer

Gelatin conditions, the intermediate heat treatment :

Time temp. Speed (min.) ⁰ C ^: speed
-. '; (mpm)

% Mixed polymer
in the coating solution _;

degree of
"Anchoring

X-ray litho emulsion graphic

emulsion

tr./ f.; ^; tr./f.

10.8 10.8 10.8 10.8 10.8 10.8 10.8 10.8 10.8

A. no 25th • 124 5.66 A. o, 5 155 3.05 A. 1 % gel. 0.5 165 3.05 B. no 25th 124 3.66 B. Il 0.5 170 3.05 B. 1 % gel 0.5 170 5.05 Q no 25 ' ^! 124 3.66 0 no 0.5 160 5.05 σ 1 % gel. 0.5 160 ° 3jO5

4th
5
5
4th

5
5
4th

5
5

0/0
2/3
0/0
0/0

3/3
0/0
0/0
0/0
0/0

0/2 0/2 0/1 0/0 2/2 2/0 0/3 0/3 0/0

*) mpm » m / min.

**) tr - dry, f &. wet

CT5

CD

CX>

O CQ

Claims (1)

Claims I.) Process for the production of biaxially oriented polyester films provided with an adhesive layer, the surface of which has been pretreated, characterized in that the pretreated surface of the film is coated with a 1 to 15% aqueous dispersion of such a copolymer which has at least two ethylenic Contains unsaturated monomers, one of which is an aliphatic ^ unsaturated carboxylic acid, the transition temperature of the second order of the copolymer being between -30 and +30 ⁰ G, whereupon the coated film is dried, in particular at temperatures between 60 and 100 °, and the copolymer on the polyester film is heated for at least 7 seconds to temperatures between 120 and 180 ° for curing o Process according to Claim 1, characterized in that at least one film surface, which is a mixed polymer is coated with a hydrophilic, colloidal layer such as gelatin. 3. X method according to claim 2, characterized in that the hydrophilic, colloidal layer is light-sensitive, in particular a gelatin-silver halide schiant. 4.) Method according to one of the preceding claims, characterized in that the pretreatment of the FiImoberflache effected with the help of electrical discharge or by treatment with a flame » 5.) Method according to claim «! up to 4, characterized that one processed a copolymer which 70 to 90 wt .- # methyl acrylate, 3 to 30 wt .- ^ itaconic acid andbjszu. 009842/18 52 BAD OFIIGiNAt 20 wt .- o "containing compound having at least zxrei unsaturated Molekulbestandteile of which xvenigsteiis a ^r a All3 l- or one Yinylgruppe, glycidyl acrylic or methacrylate at odci" rliphatischen a bifunctional i ^»l umai '. ^{> is} acid or a methacrylic acid ester, the alcohol component of which is substituted by hydroxyl groups. " 6.) 'ferfahren according to claim 1 to 5, characterized in that a.sSl rii;.: Capoljinere r..u 70 to 90 ; o from alfcylacrylate, to / to 20 , i> from Moilylseba ^ at and: .u '-) to jö -J consists of itaconic acid. 7 ·) Method according to A-ifjjug 1 to ^, by means of which a KI sciipo linier is processed, the 70 1: 1 ·· 90% Ilethylacr ^ lat, 7 to 20 Jo diallyl phthalate and;> to yO, u Contains itaconic acid with an Ivemer Konplesr. ^0098/17/1852