DE1961374A1 - Film materials with improved adhesive layers - Google Patents

Description

PATENT DEPARTMENT

LEVERKUSEN

_{Gs / ¥ s}

! Film materials with improved adhesive layers

The invention "relates to improved adhesive layers of film recording materials and the film materials themselves provided with such adhesive layers. I

In the published Dutch patent application 6813952 film recording materials are described which consist of a layer (A) which is directly adhered to the hydrophobic film support. This layer consists of a mixed polymer composed of 45-99 »5% by weight of at least one of the chlorine-containing monomeric vinylidene chloride and vinyl chloride, further of 0.5-10% by weight of an ethylenically unsaturated hydrophilic monomer and of 0-54 »5% by weight of at least one other copolymerizable, ethylenically unsaturated monomer. On top of this layer (A) is a layer (B) which, in a weight ratio of 1: 3 to 1: 0.5, contains a mixture of gelatin and a copolymer of 30-70% by weight butadiene and at least one copolymerizable Contains ethylenically unsaturated monomers.

The term "film recording materials" in the above application stands for materials which can be used for a wide variety of light recording systems. Examples of such systems are the known photosensitive silver halide emulsions, electrophotographic and electrographic systems, and a recently developed photosensitive system in which the recording is carried out by means of photosensitive semiconductor substances.

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It has now been found that when a polyester film, for example a polyethylene terephthalate film, is used as the base. the above-described second adhesive layer composed of a mixture of gelatin and a butadiene copolymer can be omitted if, after the application of the first adhesive layer, the surface of this first layer is exposed to a high voltage corona discharge.

The invention thus relates to a method for improving the adhesion of a hydrophilic layer of a recording material on a layer which consists of a copolymer, the at least one of the chlorine-containing monomers Contains vinylidene chloride and vinyl chloride. The layer containing the mixed polymer lies on a polyester film and the method consists in the surface of this layer prior to the application of the hydrophilic layer of a Suspend corona discharge.

The method according to the invention can be carried out in such a way that the film substrate provided with the adhesive layer is passed, for example, between a grounded orphan and a corona electrode, the polymer layer facing the corona electrode. The corona electrode is connected to a source of alternating current so that it provides a high frequency corona discharge.

The treatment with the corona discharge can take place at any time before the application of the second layer to the coated polyester film. However, it is advantageous to carry out the treatment immediately before applying the second layer. The frequency range of 10-100 kHz has proven to be particularly suitable. Suitable current intensities are in the range between 0.5 × 10 ^J and 1.5 × 10 ^J A / cm, based on the length of the corona electrode.

Hydrophobic polyester film substrates suitable for the process according to the invention consist of high-polymer linear polyesters such as, for example, polyethylene terephthalate. Such film substrates are coated with layers of vinylidene chloride and / or vinyl chloride copolymers and exposed to an ooron exposure, creating a layer system which can be used in a variety of ways.

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For example, a hydrophilic layer can be applied to the electrically treated adhesive layer, either transferred from another material or applied as a liquid. The hydrophilic layer may contain one or more of the following substances:

a) semiconductor substances in a suitable binder;

b) electrically conductive substances in a suitable binder;

c) pigments in a photo-curable or soluble binder;

d) matting agents or opaque white pigments in a suitable binder;

e) light-sensitive substances, as well as photosensitive silver halide, and other photoconductive substances lichtempfind- ä Liehe compounds such as diazonium salts and diazosulfonates;

f) dissolved dyes, e.g., a bleachable dye;

g) Color couplers, such as those used in silver halide color photography common color coupler;

h) Development nuclei such as those used in the production of silver images by the silver halide reversal diffusion process are common.

In the case of recording processes which produce a hydrophilic relief image, a hydrophilic layer can be transferred by peeling off a temporary support onto a final layer support, which is then provided with an adhesive layer according to the invention. According to a particular exemplary% form contains the hydrophilic layer photosensitive semiconductor compounds, mixtures or materials that are capable of forming a latent recording upon image-wise exposure, which is then developed with an aqueous solution (see "Unconventional Photographic System ^11, Second Symposium, October 26-28, 1967, Washington DO, pages 116-117). the sheet material according to the invention can also be used as cover material, especially if it is provided with layers calibrated specifically suitable for receiving printing. on the other hand, allows the sheet material but also as a sign

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use film.

A particularly interesting field of application of the invention Sheet material are recording materials which carry a hydrophilic pigment layer, e.g. pigmented Gelatin layers, which are used to create relief images suitable, which are generated by means of a photoreaction which hardens or solubilizes the layer. Such Pigment layers are mainly used in the graphic sector interesting and especially for color testing as described in the published Dutch patent application 6907436, as well as in Example 16 of published Dutch patent application 6909129.

The layer consisting of a copolymer of vinylidene chloride and / or vinyl chloride is hereinafter referred to as the "vinylidene chloride copolymer" layer are designated. The tinylidene chloride copolymer contains 0.5-10 wt .- ^ Ethylenically unsaturated hydrophilic monomer units. These units can be of ethylenically unsaturated mono- or Dicarboxylic acids such as acrylic acid, methacrylic acid and itaconic acid can be derived. Also other hydrophilic units, e.g. those that derived from N-vinylpyrrolidone come into consideration.

The vinylidene chloride copolymer can be composed of vinylidene chloride and / or vinyl chloride and hydrophilic monomeric units can be produced solely in the ratio given above. Preferably, up to 54.5% by weight of other repetitive Units, e.g. acrylamides, methacrylamides, acrylic acid esters, methacrylic acid esters, maleic acid esters, N-alkyl maleimides and / or butadiene may be involved. Examples of suitable vinylidene chloride copolymers are: the mixed polymer of vinylidene chloride, N-tert.-butyl acrylamide,

n-butyl acrylate and N-vinylpyrrolidone (70: 23: 3: 4), the mixed polymer of vinylidene chloride, N-tert.-butyl acrylamide,

η-butyl acrylate and itaconic acid (70: 21: 5: 4), the mixed polymer of vinylidene chloride, N-tert-butyl acrylamide

and itaconic acid (88: 10: 2),
the mixed polymer of vinylidene chloride, N-tert-butyl acrylamide, n-butyl acrylate and methacrylic acid (65: 15: 3: 17),

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the mixed polymer of vinylidene chloride, ri-butyl maleimide and Itaconic acid (90: 8: 2),

the mixed polymer of vinylidene chloride, N-tert.-butyl acrylamide, Butadiene and itaconic acid (70: 18: 10: 2),

the mixed polymer of vinyl chloride, vinylidene chloride and methacrylic acid (65: 30: 5),

the mixed polymer of vinylidene chloride, vinyl chloride and itaconic acid (70: 26: 4),

the mixed polymer of vinyl chloride, n-butyl acetate and itaconic acid (66: 30: 4),

the mixed polymer of vinylidene chloride, n-butyl acrylate and Itaconic acid (80: 18: 2),

the mixed polymer of vinylidene chloride, methyl acrylate and

Itaconic acid (90: 8: 2),

the mixed polymer of vinyl chloride, vinylidene chloride, N-tert-butyl acrylamide and itaconic acid (50: 30: 18: 2),

the mixed polymer of vinyl chloride, vinylidene chloride, n-butyl acrylate and itaconic acid (63: 30: 5: 2).

The figures in brackets here represent weight ratios represent.

The abovementioned copolymers are only examples of possible combinations of different monomers, i.e. the Invention is not intended to be limited to them.

The abovementioned monomers can be copolymerized by various methods, for example in an aqueous j Dispersion containing a catalyst and an activator. Another possibility is to use the monomeric components polymerize in bulk without a diluent or the monomers react in a suitable organic medium allow.

All known methods can be used for applying the vinylidene chloride copolymers to the polyester film base. For example, the surface of the film can be dipped into a solution of the coating material, or the application is carried out by spraying using a brush, a roller, a doctor blade or an air brush. The thickness of the dried layer should preferably be between Q _f 3 and 3 / u AG 584 - 5 -

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lie.

If the vinylidene chloride mixed polymer layer is applied from an aqueous dispersion, then various Wetting or dispersing agents can be used. When the interpolymer is produced by an emulsion polymerization process this dispersion is obtained directly. A special adhesion to the base is achieved if the applies aqueous dispersion of the vinylidene chloride copolymer before or during the stretching of the polyethylene terephthalate film .

The aqueous dispersion can be applied to at least one side of the unstretched film, but it can be also on a biaxially oriented polyethylene terephthalate film shed. The vinylidene chloride copolymer layer can also be used also on at least one side of one that is stretched in only one direction, for example one that is elongated Apply polyester film and those equipped with the adhesive layer Then stretch the film again perpendicular to the first direction, in this case in the transverse direction. The following examples serve to illustrate the invention. The vinylidene chloride copolymers used in these examples are made according to the procedure described in published Dutch patent application 6813952 manufactured.

example 1

The following mixture is applied in a ratio of 1.4 g / m to one side of a biaxially oriented polyethylene terephthalate film with a thickness of 180 / u? Mixed polymer of vinylidene chloride,
n-tert-butyl acrylamide, n-butyl acrylate and N-vinylpyrrolidone
(70: 23: 3: 4)

Methylene chloride 1,2-dichloroethane Methanol

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5 G 60 ml 35 ml 5 ml

After the layer has dried, its surface is exposed to four successive corona discharges, which are generated by means of a high-frequency high-voltage source. The high-voltage source supplies a pulsating voltage in which pulses of 500 kV are followed by low voltages of 5 kV. The frequency is about 35 kHz, the current intensity for each electrode 1.5 x 10 ^-5 A / cm and the film speed is 10 m / min.

After the corona treatment, the vinylidene chloride mixed polymer layer is coated with the mixture described below (about 2 g ZnO / m ² ).

80 g of zinc oxide are dispersed with stirring in 450 ml of deionized water to which 1.5 g of sodium hexametaphosphate are added | Has. To this are added at 40 ⁰ C a solution of 53 g of gelatin in 550 ml of demineralized water, 7 ml of a 12.5 wt .- ^ solution of saponin in demineralized water and 7 ml of a 20 wt .-? 6igen solution of formaldehyde in demineralized water together with 45 ml of ethylene chlorohydrin. The dried photosensitive material is exposed imagewise through a transparent original and immersed in the following baths:

5 sbc in a 5 # solution of silver nitrate in demineralized Water,

5 see in a 0.6 $ solution of p-monomethylaminophenyl sulfate in demineralized water,>

30 see in an acidic fixer containing 200 g of sodium thiosulfate pentahydrate and contains 25 grams of potassium metabisulfite per liter.

The material is then washed in running water for 5 minutes and then dried. A black negative image is obtained the template.

The adhesive strength of the photosensitive layer on the base provided with an adhesive layer was both im dry as well as in the wet state very well. If the corona treatment is omitted, the adhesion is the photosensitive Layer significantly worse.

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Example 2 O

On one side of unstretched polyethylene terephthalate film is made from an aqueous suspension of a copolymer from vinyl chloride, vinylidene chloride, n-butyl acrylate and itaconic acid (63: 30: 5: 2) an adhesive layer is applied, after which the polyethylene terephthalate film is oriented. The vinylidene chloride blend polymer layer is, as described in Example 1, exposed to a corona discharge, the current intensity is reduced to 0.6 10 A / cm.

After the corona treatment, the vinylidene chloride mixed polymer layer is coated with the pigment dispersion described below.

35 g of titanium dioxide with a particle size of 15-35 nm and a specific surface area of approximately 50 m / g are stirred for 2 minutes with 150 ml of demineralized water and 0.75 g of sodium hexametaphosphate using an Ultra-Turrax mixer, so that a homogeneous dispersion is formed . A solution of 35 g of gelatin in 500 ml of demineralized water and 100 ml of ethylene chlorohydrin in 250 ml of water is added in succession to the mixture thus prepared, while stirring. Finally, 5 ml of a 4-point solution of formaldehyde in demineralized water are added.
This pigment dispersion is applied to the vinylidene chloride mixed polymer layer in such a way that the layer contains 2 g of titanium dioxide

ρ
per m contains.

The dried material is then exposed imagewise through a transparent original and then successively with it treated in the following baths:

1) 30 seconds in a 10% strength by weight solution of silver nitrate in demineralized water;

2) 30 seconds in a 3 wt .- ^ solution of p-Monomerthylaminophenylsulfat in demineralized water;

3) 60 seconds in an acidic fixer containing 200 g of sodium thiosulfate pentahydrate and contains 25 grams of potassium metabisulfite per liter.

After washing and drying, a sharp black negative silver image of the original is obtained.

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The titanium dioxide layer adheres very well to the vinylidene chloride mixed polymer layer. Without the corona treatment, the titanium dioxide layer can be easily removed from the adhesive layer of the Separate polyester film.

Example 3

Example 2 is repeated with the difference that the vinylidene chloride mixed polymer layer is replaced by a mixture of 3 parts by weight of a copolymer of vinylidene chloride, N-tert-butyl acrylamide, n ~ butyl acrylate and methacrylic acid (65: 15: 3: 17) and 2.5 parts by weight of a copolymer of vinylidene chloride, N-tert-butyl acrylamide, n-butyl acrylate and N-Viny! Pyrrolidone (70: 23: 3: 4) dissolved in 80 parts by weight Methylene chloride and 20 parts by weight of methyl glycol. |

As described in Example 1, four are used in succession Corona discharges with a? Current intensity based on 1.3 10 A / cm is reduced.

Without the corona treatment, the titanium dioxide layer adheres to the wet state not on the vinylidene chloride mixed polymer layer. After applying the corona treatment, the adhesive strength is excellent.

Example 4

Example 1 is repeated by the Vinylidenchloridmischpolymermischung is replaced by a 5 wt .- # solution of a mixed polymer of vinylidene chloride, N-tert-butyl i acrylamide, butadiene, and itaconic acid (70: 18: 10: 2) in 60 parts by volume of methylene chloride , 35 parts by volume of 1,2-dichloroethane and 5 parts by volume of methanol. The corona treatment is carried out as in Example 3. The pigment layer adheres very well, while without corona treatment it does not adhere to the vinylidene chloride layer either in the dry or in the wet state.

Example 5

An unstretched polyethylene terephthalate film is provided with an adhesive layer which consists of an aqueous suspension

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a mixed polymer of vinylidene chloride, methyl acrylate and itaconic acid (88: 10: 2) exists. Then the polyethylene terephthalate film oriented "

The vinylidene chloride blend polymer layer is as in Example 1 described exposed to a corona discharge, the current intensity being reduced to 1.0 χ 10 "* A / cm. Finally the pigment layer given in Example 1 is applied. The adhesive strength in the wet and dry state is very good.

Example 6

On one side of an unstretched polyethylene terephthalate film an adhesive layer is applied, which consists of 20 wt .- # of the latex of a copolymer of vinyl chloride, vinylidene chloride, n-butyl acrylate and itaconic acid (63: 30: 5: 2) and contains 3 wt .- # formamide.

The PiIm provided with the adhesive layer is biaxially oriented. The vinylidene chloride mixed polyning layer is then treated as described in Example 1 with the corona discharge.

The material is finally coated with a gelatin silver halide emulsion layer, as they are used for X-ray materials is coated. The adhesion of the emulsion layer to the adhesive layer of the base is excellent. the Fog values and the sensitivity of the photographic emulsion are hardly affected by the corona discharge.

Example 7

An unstretched polyethylene terephthalate film is provided with an adhesive layer consisting of an aqueous suspension of a copolymer of vinyl chloride, vinylidene chloride, n-butyl acrylate, β-chloroethyl acrylate and itaoonic acid (43:30: 5: 20: 2). After the film has been biaxially tarted, the rope of this film is subjected to a corona discharge according to Example 1, while the other part is left untreated.

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Both film bases are then coated with a gelatin silver halide emulsion layer coated for lithographic purposes. The adhesion of the emulsion layer is on the surface of the with of the corona discharge treated film both in the dry and in the wet state, while on the untreated film Film no liability whatsoever was found.

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Claims (12)

Claims H2 Process for improving the adhesion of a hydrophilic layer of a recording material to the layer of a Copolymers containing at least one of the chlorine-containing monomers vinylidene chloride and vinyl chloride, wherein the layer of the mixed polymer is applied to a polyester base, characterized in that the surface the layer of the copolymer is exposed to a high-voltage corona discharge before the application of the hydrophilic layer will. 2. Recording material consisting of a polyester film as a base, a layer of a mixed polymer containing at least one of the chlorine-containing monomers vinylidene chloride and vinyl chloride contains, and a hydrophilic layer whose adhesion to the layer of the mixed polymer according to claim 1 is improved has been. 3. Recording material according to claim 2, wherein the mixed polymer from 45 - 99.5 wt .- ^ at least one of the chlorine-containing Monomers vinylidene chloride and vinyl chloride, from 0.5-10 wt .- ^ an ethylenically unsaturated hydrophilic monomer and from-0 - 54.5 wt .-? δ of at least one other copolymerizable Ethylenically unsaturated monomers. 4. Recording material according to Claims 2 and 3, which is a compound as the ethylenically unsaturated hydrophilic monomer from the group of acrylic acid, methacrylic acid, itaconic acid and contains N-vinyl pyrrolidone. 5. Recording material according to claims 2-4, containing up to 54.5 wt .- # of at least one of the monomers acrylamide, Contains methacrylamide, acrylic acid esters, methacrylic acid esters, maleic acid esters, N-alkyl maleimides and butadiene. 6. Recording material according to one of claims 2-5, wherein the polyester film base is a polyethylene terephthalate film. AG 584 - 12 - 009 8 27/1890 7. Recording material according to one of claims 2-6, wherein the surface of the layer of the copolymer of a high frequency Equence corona discharge with a frequency range of 10-100 kHz —5 is exposed to the current intensities of 0.5 x 10 A / cm, based on the length of the gorona electrode. 8. A recording material according to any one of claims 2-7, wherein the layer of the copolymer of a latex of a mixed polymer of vinylidene chloride, vinyl chloride, n-butyl acrylate and itaconic acid " 9. Recording material according to one of claims 2-8, wherein the layer of the mixed polymer from a solution of a Mixed polymers of vinylidene chloride, F-tert.-butyl acrylamide, n-butyl acrylate and N-vinylpyrrolidone has been produced. ™ 10. Recording material according to one of claims 2-9, containing a photosensitive silver halide emulsion layer coated on the layer of a copolymer that has been exposed to a corona discharge. 11. Recording material according to one of claims 2-9, which contains a photosensitive semiconductor layer which has been applied to the layer of a copolymer which has been treated with a corona discharge. 12. Recording material according to claim 11, which is used as photosensitive Semiconductor material contains finely divided titanium dioxide or zinc oxide. AG 584 - 13 - 009827/1890