EP0870623A1 - Recording material for receiving water-based inks - Google Patents

Abstract

A recording material (I) having at least one colour receiving layer (A) for absorption of a water-soluble dye solution, in which the layer (A) contains (i) an epoxide-crosslinkable, carboxylic acid group-containing, cationic copolymer (II); (ii) an epoxide-containing metal oxide (III); and (iii) a water-soluble polymer (IV). Also claimed is a process for the production of (I), by making a coating solution from copolymer (II), metal oxide sol (III) and polymer (IV), coating this solution onto a substrate material, gelling and then drying to form layer (A).

Description

The invention relates to a recording material for water-dilutable Inks, especially for use with inkjet printers, and a process for its manufacture.

Image recording or reproduction using inkjet printers is a common method because it is direct and fast implementation of electronic image data is possible. Modern printer technology allows image reproduction with a Resolution, which is the resolution of the image displayed with the corresponds to conventional silver halide photography, below Use of various print media such as paper backing or transparent films. The quality of the pictures, in particular The resolution depends on both the possibilities of the used Printer as well as crucial from the properties ds recording material. The recording material further determines the further handling and the possible applications of the finished pictures. The aim is that the Recording material meets the following requirements: good Ink absorption to achieve high color densities; low Diffusion of the ink (dye solution) in the recording material, to keep the droplet size small and thus high sharpness of contours and good resolution achieve; fast drying and good smudge resistance after the Ink application; low stickiness even with high air humidity; high transparency of the recording material Training as projection screen; and low sensitivity to water and therefore suitability for outdoor applications.

Conventional recording materials realize this Requirements are not and are therefore in their application limited.

In the case of recording materials with paper substrates, a fast ink absorption and smudge resistance thanks to Modification of a color absorption layer with high pigment quantities realized (DE 3 024 205, EP 379 964). This occurs however, a strong cloudiness, so that modified in such a way Recording materials are not suitable as projection foils are. It is known to make ink-receptive layers from water-soluble Polymers, e.g. Polyvinyl alcohol, polyvinyl pyrrolidone, To provide gelatin etc. (US 4,503,111, US 4,680,235, US 4,555,432, DE 4,405,969). These polymers are characterized by a high moisture influence Stickiness and lack of water resistance. The stake of cationic polishing as a binder for fixing the Dyes in a color absorption layer and to increase the Wipe resistance is known from DE 3 707 624 or EP 514 633. Polymer mixtures of polyvinyl alcohol or polyalkylene oxides can also be used can be used with cationic polymers (EP 379 964, EP 634 284, JP 56-84992, JP 59-20696).

The use of metal oxide sols as fillers is in the EP 524 626 and DE 4 405 969. To improve the Smudge resistance is known to silane the binder solutions add to form matrix polymers (see EP 583 141, EP 482 837). To reduce water sensitivity proposed acidic, water-insoluble in EP 233 703 Polyacrylates and polyvinyl pyrrolidone as a color receiving layer to use.

It is also known to manufacture 2-layer systems, one microporous polyvinyl acetate top layer to improve the Have smudge resistance. However, this will increase transparency reduced, so that an application as a projection film is impossible. It is therefore proposed for film carriers water-soluble copolymers based on acrylic acid or p-styrene sulfonic acid with polyfunctional aziridines network (EP 482 838). Through this networking, however Drying time of the applied ink is negatively affected.

The known recording materials meet the above Requirements not. In particular, they are not for Suitable applications where a moisture or Water contact is possible because the swelling or solution Color receiving layer dye extracted from the layer is, so that the color densities achieved and develops poor contour definition.

The object of the invention is to provide a new recording material, which has improved moisture and water resistance owns, and a process for its preparation specify. The recording material is intended in particular to have a wider range of applications and practical drying times after ink application.

This object is achieved by a material according to claim 1 and Method according to claim 8 solved. Advantageous embodiments result from the subclaims.

A recording material according to the invention has one Color receiving layer, which contains an epoxy-crosslinkable, carboxylic acid group cationic copolymer, a water-soluble Polymer and an epoxy-containing metal oxide sol contains. The weight fractions are preferably each corresponding to 30 to 60% by weight of the copolymer, 30 to 60 % By weight of the metal oxide and 10 to 40% by weight of the water-soluble Polymer.

wobei

M:

carbonsäurehaltiges Monomer

Z:

Vinylmonomer

A:

Sauerstoff oder Stickstoff

R₁:

H, CH₃

R₂:

Alkylengruppe von C₂ bis C₈

R₃:

CH₃, C₂H₅, C₃H₇, C₄H₉

X:

Chlorid, Bromid, und

a:

10 bis 50 Mol-%, b: 0 bis 20 Mol.-%, c: 50 bis 90 Mol.-%

bedeuten.The epoxy-crosslinkable, carboxylic acid-containing cationic copolymer has the structural formula:

in which

M:

monomer containing carboxylic acid

Z:

Vinyl monomer

A:

Oxygen or nitrogen

R ₁ :

H, CH ₃

R ₂ :

Alkylene group from C ₂ to C ₈

R ₃ :

CH ₃ , C ₂ H ₅ , C ₃ H ₇ , C ₄ H ₉

X:

Chloride, bromide, and

a:

10 to 50 mol%, b: 0 to 20 mol%, c: 50 to 90 mol%

mean.

Acrylsäure-Methacryloxyethyl-trimethylammoniumchlorid-Copolymere:

Acrylsäure-Ethylacrylat-Methacryloxyethyltrimethylammoniumchlorid-Terpolymer:

Acrylsäure-Methacrylamidopropyl-trimethylammoniumchlorid-Copolymer

Examples of such crosslinkable polymers of the general structural formula given are:

Acrylic acid-methacryloxyethyl-trimethylammonium chloride copolymers:

Acrylic acid-ethyl acrylate-methacryloxyethyltrimethylammonium chloride terpolymer:

Acrylic acid-methacrylamidopropyl trimethyl ammonium chloride copolymer

The component of the crosslinkable polymer can also be a Composition from different polymers according to the general structural formula included.

The carboxylic acid-containing monomer unit is acrylic acid, Methacrylic acid or itaconic acid is preferred. In this case the content in the polymer component is preferably 20 to 35 mol%. In addition to ethyl acrylate as a comonomer component all known vinyl monomers, e.g. Vinyl pyrrolidone, Styrene, acrylamide or vinyl acetate act. The molecular weight this polymer component is usually 10,000 D to 500000 D.

• Glycidoxypropyltrimethoxysilan,
• Glycidoxypropyltriethoxysilan, und
• (3,4-Epoxycyclohexylethyltrimethoxysilan).

The metal oxide sol component is produced in a known manner by means of sol / gel technologies from epoxy-containing metal oxide sols with an organic solvent (for example methanol, ethanol) (see US 3 955 035, HI Schmidt et al. Non-Cryst. Solids 80 (1989) 557) . Hydrolysates of epoxy silanes are preferably used. Examples of the epoxy-containing, hydrolyzable silanes are:

• Glycidoxypropyltrimethoxysilane,
• Glycidoxypropyltriethoxysilane, and
• (3,4-epoxycyclohexylethyltrimethoxysilane).

The hydrolysis and condensation can be carried out in the presence of tetraalkoxysilanes, Alkyltrialkoxysilanes or dialkyldialkoxysilanes is carried out, whereby the epoxy content of the Metal oxide brine can be controlled in a targeted manner. According to the invention also metal oxide mixtures can be used by the Sol production alkoxylates of boron, aluminum or titanium as Co building blocks act.

When crosslinking the epoxy groups or gel formation (during drying) the epoxy-containing metal oxide sols react with the free carboxylic acid groups of the polymers and thus result a water-insoluble network of metal oxide and cationic Polymer. To accelerate this reaction, the Composition additional epoxy catalysts may be added.

Examples of epoxy catalysts are triethylamine, dimethylbenzylamine and N-methylimidazole. Based on the epoxy The concentration of metal oxide sol is preferably 1 to 5 % By weight.

The second, water-soluble polymer component is preferred a nonionic or cationic water soluble polymer. This can be done, for example, with polyvinyl alcohol, polyvinyl pyrrolidone, Polyacrylamide, cationic polyacrylamide, cationic polyacrylic esters or compositions thereof be formed.

The recording material according to the invention can in the color receiving layer furthermore means for controlling the layer uniformity and surface tension included. For this are particularly suitable nonionic or cationic surfactants. Hexadecyltrimethylammonium bromide is particularly preferred.

The recording material according to the invention can be used as a carrier material contain a flexible support for printing is suitable in an inkjet printer. Here are preferably paper or transparent plastic films used. However, it is also possible as a carrier material rigid or non-flexible materials such as Use glass or plastic sheets. The carrier material can be essentially flat or any Have body shape, with the application of the color receiving layer possible on any surface of the carrier material is. Finally, it is possible to use the color receiving layer to produce such a thickness that a self-supporting Recording material is formed.

The production of a recording material according to the invention is done by applying a coating solution for formation an ink receiving layer on a substrate. The approach the coating solution is made by preparing a Metal oxide sol according to the above composition and addition of the polymer components. The approach is preferably carried out in aqueous-organic solvents, e.g. in one Water-ethanol mixture. The application of the coating solution on the carrier material is done by a casting process like this for example of photochemical coating processes is known. Alternatively, the carrier material can also be used Diving, spraying or a similar application process be coated. Subsequently, the Coating solution on the carrier material, which by a Heat can be accelerated.

The recording material according to the invention has the following advantages. The recording material contains one novel ink receiving layer, which is insoluble in water, at Moisture contact does not form a sticky surface and one practical drying time. The ink receiving layer is transparent and therefore for both paper and Suitable film carrier. The ink receiving layer can be with known layers of conventional recording materials combine by using the new color receiving layer as Top layer is used. After a site-specific order from Ink (dye solution) the ink dyes become solid in the crosslinked polymer composition of the ink receiving layer anchored and will not be washed out in contact with water. As a result, the use of the recording material is not limited to printing material for inkjet printers, but also possible for outdoor or outdoor use. A bleeding from smallest ink stains do not occur, so that the recording material according to the invention for recording operations (Printing processes) with resolution requirements is suitable for use with modern printing devices Production of overhead projector foils or color prints be made from photographs.

Embodiments Example 1 (comparative example)

45 Gew.-%

Gelatine (alkalisch aufgeschlossene Knochengelatine)

35 Gew.-%

Polyvinylpyrrolidon (K 90)

20 Gew.-%

epoxidfunktionelles Metalloxidsol, hergestellt aus 80 Gew.-% Tetraethoxysilan und 20 Gew.-% Glycidooxypropyltrimethoxysilan.

With a 10% by weight water / alcohol solution (40/60), a 7.8 µm thick layer of the following composition is applied to a 100 µm thick polyester base in a known manner using a doctor.

45% by weight

Gelatine (alkaline digested bone gelatine)

35% by weight

Polyvinyl pyrrolidone (K 90)

20% by weight

epoxy-functional metal oxide sol, made from 80% by weight tetraethoxysilane and 20% by weight glycidooxypropyltrimethoxysilane.

Konturenschärfe:

gut, nach Wässerung unscharfe Abbildung

Trocknungszeit:

7,5 min

Oberflächenbeschaffenheit (85% RF):

leicht klebrig, bei Wasserkontakt starkes Quellen

Transparenz:

klare Folie.

D1 (vor Wässerung) D2 (nach Wässerung) Farbdichte (purpur) 1,9 1,3 (blau) 1,7 0,9 (gelb) 0,95 0,6 After the layer has dried at 85 ° C., the film is printed on using an HP Desjet 690C inkjet printer. To characterize the properties, the color density is determined, the sharpness of the contours is assessed visually and the transparency and tackiness of the surface are determined. To test the water resistance, the film is further brought into contact with flowing water at 25 ° C. for 30 minutes and then the color density and layer properties are checked. The following properties are obtained:

Contour sharpness:

good, blurred image after watering

Drying time:

7.5 min

Surface quality (85% RH):

slightly sticky, strong swelling when in contact with water

Transparency:

clear film.

D1 (before washing) D2 (after watering) Color density (purple) 1.9 1.3 (blue) 1.7 0.9 (yellow) 0.95 0.6

The layer is not waterproof. The dye is washed out and also diffuses in the layer.

Example 2 (comparative example)

33 Gew.-%

Na-Polyacrylat

59 Gew.-%

Polyacylsäure (vernetzt in Gegenwart von Silanen gemäß EP 583 141)

8 Gew.-%

Metalloxidsole aus Tetraethoxysilan

Analogously to Example 1, an 8.5 μm thick layer of the following composition is applied:

33% by weight

Na polyacrylate

59% by weight

Polyacrylic acid (crosslinked in the presence of silanes according to EP 583 141)

8% by weight

Metal oxide sols made from tetraethoxysilane

Konturenschärfe:

gut, nach Wässerung unscharfe Abbildung

Trocknungszeit:

6,5 min

Oberflächenbeschaffenheit (85% RF):

nicht klebrig, Schicht quillt stark bei Wasserkontakt

Transparenz:

klare Folie

D1 (vor Wässerung) D2 (nach Wässerung) Farbdichte (purpur) 1,7 1,1 (blau) 1,4 0,4 (gelb) 0,6 0,3 The following properties are obtained:

Contour sharpness:

good, blurred image after watering

Drying time:

6.5 min

Surface quality (85% RH):

not sticky, layer swells strongly when in contact with water

Transparency:

clear film

D1 (before washing) D2 (after watering) Color density (purple) 1.7 1.1 (blue) 1.4 0.4 (yellow) 0.6 0.3

The layer is not waterproof. The dye diffuses in the layer and is washed out considerably.

Example 3

45 Gew.-%

Copolymeres aus Acrylsäure und Methacryloxyethyltrimethylammoniumchlorid (20/80), Molekulargewicht 130000 D,

45 Gew.-%

Metalloxidsol, hergestellt aus 75 Gew.-% Tetraethoxysilan und 25 Gew.-% Glycidopropyltrimethoxysilan

10 Gew.-%

Polyvinylalkohol (voll verseift, Molekulargewicht 95000 D)

Analogously to Example 1, an 11.5 μm thick layer of the following composition is applied:

45% by weight

Copolymer of acrylic acid and methacryloxyethyltrimethylammonium chloride (20/80), molecular weight 130,000 D,

45% by weight

Metal oxide sol made from 75% by weight tetraethoxysilane and 25% by weight glycidopropyltrimethoxysilane

10% by weight

Polyvinyl alcohol (fully saponified, molecular weight 95000 D)

Konturenschärfe:

gut, auch nach Wässerung scharfe Abbildungen

Trocknungszeit:

7,0 min

Oberflächenbeschaffenheit:

nicht klebrig, bei Wasserkontakt klebefreie unlösliche Schicht

Transparenz:

klare Folie.

D1 (vor Wässerung) D2 (nach Wässerung) Farbdichte (purpur) 1,9 1,85 (blau) 1,6 1,5 (gelb) 0,9 0,9 The following properties are obtained.

Contour sharpness:

good, sharp images even after watering

Drying time:

7.0 min

Surface quality:

not sticky, non-sticky layer on contact with water

Transparency:

clear film.

D1 (before washing) D2 (after watering) Color density (purple) 1.9 1.85 (blue) 1.6 1.5 (yellow) 0.9 0.9

The layer is waterproof. In the case of water contact, none noticeable bleaching of the dye. After drying sharp images will be obtained again.

Example 4

55 Gew.-%

Mischpolymerisat aus Acrylsäure/Ethylacrylat/Methacryloxyethyltrimethylammoniumchlorid (28/12/60), Molekulargewicht 140000 D.

35 Gew.-%

Metalloxidsol aus 50 Gew.-% Glycidoxypropyltriethoxysilan und 50 Gew.-% Tetraethoxysilan

10 Gew.-%

Polyvinylpyrrolidon, Molekulargewicht 320000 D.

Analogously to Example 1, a 12.5 μm thick layer of the following composition is applied:

55% by weight

Copolymers of acrylic acid / ethyl acrylate / methacryloxyethyltrimethylammonium chloride (28/12/60), molecular weight 140,000 D.

35% by weight

Metal oxide sol composed of 50% by weight glycidoxypropyltriethoxysilane and 50% by weight tetraethoxysilane

10% by weight

Polyvinyl pyrrolidone, molecular weight 320,000 D.

Konturenschärfe:

gut, auch nach Wässerung scharfe Abbildungen

Trocknungszeit:

7,0 min

Oberflächenbeschaffenheit (85% RF):

nicht klebrig, bei Wasserkontakt klare nichtklebrige Schicht

Transparenz:

klare Schicht

D1 (vor Wässerung) D2 (nach Wässerung) Farbdichte (purpur) 2,1 2,0 (blau) 1,8 1,7 (gelb) 0,9 0,85 The following properties are obtained:

Contour sharpness:

good, sharp images even after watering

Drying time:

7.0 min

Surface quality (85% RH):

not sticky, clear non-sticky layer on contact with water

Transparency:

clear layer

D1 (before washing) D2 (after watering) Color density (purple) 2.1 2.0 (blue) 1.8 1.7 (yellow) 0.9 0.85

The layer is waterproof. There is no watering significant washout of the dye. After drying sharp images will be obtained again.

Example 5

48,5 Gew.-%

Copolymer aus Acrylsäure und Acrylamidopropyltrimethylammoniumchlorid (35/65), Molekulargewicht 195000 D.

40 Gew.-%

Metalloxidsol, hergestellt aus 80 Gew.-% Tetraethoxysilan und 20 Gew.-% Glycidoxypropyltrimethoxysilan

10 Gew.-%

Poly-methacrylamidopropyltrimethylammoniumchlorid, Molekulargewicht 85000 D.

1,5 Gew.-%

Hexadecyltrimethylammoniumbromid.

Analogously to Example 1, a 10.5 µm thick layer of the following composition is applied:

48.5% by weight

Copolymer of acrylic acid and acrylamidopropyltrimethylammonium chloride (35/65), molecular weight 195000 D.

40% by weight

Metal oxide sol made from 80% by weight tetraethoxysilane and 20% by weight glycidoxypropyltrimethoxysilane

10% by weight

Poly-methacrylamidopropyltrimethylammonium chloride, molecular weight 85000 D.

1.5% by weight

Hexadecyltrimethylammonium bromide.

Konturenschärfe:

gut, auch nach Wässerung scharfe Abbildungen

Trocknungszeit:

7,5 min

Oberflächenbeschaffenheit (85% RF):

nicht klebrig, auch bei Wasserkontakt

Transparenz:

klare Schicht

D1 (vor Wässerung) D2 (nach Wässerung) Farbdichte (purpur) 2,0 1,95 (blau) 1,9 1,8 (gelb) 0,8 0,8 The following properties are obtained:

Contour sharpness:

good, sharp images even after watering

Drying time:

7.5 min

Surface quality (85% RH):

not sticky, even when in contact with water

Transparency:

clear layer

D1 (before washing) D2 (after watering) Color density (purple) 2.0 1.95 (blue) 1.9 1.8 (yellow) 0.8 0.8

The layer is waterproof. There is no contact with water significant washout of the dye. After drying sharp images will be obtained.

The examples show compared to the conventional comparative examples a high density, constant after contact with water, dry, non-sticky surfaces and high transparency too after contact with water and drying again. The ink receiving layer has a largely non-toxic composition.

Claims (10)

Recording material which has at least one ink receiving layer which is provided for receiving a water-soluble dye solution,
characterized in that
the ink-receiving layer contains an epoxy-crosslinkable, carboxylic acid-containing cationic copolymer, an epoxy-containing metal oxide and a water-soluble polymer. The recording medium according to claim 1, wherein the Parts by weight of the epoxy-crosslinkable, carboxylic acid group-containing cationic copolymer 30 to 60 wt .-%, des epoxy-containing metal oxide 30 to 60 wt .-% and the water-soluble Polymers amount to 10 to 40 wt .-%. Recording material according to one of the preceding claims, in which the epoxy-crosslinkable, carboxylic acid group-containing cationic copolymer has the structural formula

owns, whereby

M:

monomer containing carboxylic acid

Z:

Vinyl monomer

A:

Oxygen or nitrogen

R ₁ :

H, CH ₃

R ₂ :

Alkylene group from C ₂ to C ₈

R ₃ :

CH ₃ , C ₂ H ₅ , C ₃ H ₇ , C ₄ H ₉

X:

Chloride, bromide

a:

10 to 50 mol%

b:

0 to 20 mol%

c:

50 to 90 mol%

mean. Recording material according to one of the preceding Claims, wherein the color receiving layer means for Control of layer uniformity and surface tension contains. Recording material according to one of the preceding Claims, wherein the at least one color receiving layer with a carrier material is connected. A recording material according to claim 5, wherein the carrier material is a transparent plastic layer or paper. Use of a recording material according to one of the Claims 1 to 6 as a printing pad for inkjet printers. A method for producing a recording material which contains at least one color receiving layer which is intended for receiving a water-soluble dye solution, comprising the steps: Preparation of a coating solution from an epoxy-crosslinkable, carboxylic acid group-containing cationic copolymer, an epoxy-containing metal oxide sol and a water-soluble polymer, Application of the coating solution on a carrier material and Gelation and drying of the coating solution to form the ink receiving layer. The method of claim 8, wherein the coating solution an epoxy catalyst is added. The method of claim 8 or 9, wherein the application the coating solution by pouring a transparent Plastic film or a paper carrier material is made.