Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
  • B41N3/00—Preparing for use and conserving printing surfaces
  • B41N3/03—Chemical or electrical pretreatment
  • B41N3/038—Treatment with a chromium compound, a silicon compound, a phophorus compound or a compound of a metal of group IVB; Hydrophilic coatings obtained by hydrolysis of organometallic compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
  • B41N3/00—Preparing for use and conserving printing surfaces
  • B41N3/03—Chemical or electrical pretreatment
  • B41N3/036—Chemical or electrical pretreatment characterised by the presence of a polymeric hydrophilic coating

Definitions

• the invention relates to plate, film or ribbon-shaped support materials for offset printing plates based on aluminum with a hydrophilic coating, a process for the production of these materials and the use of the materials in the production of offset printing plates.
• Backing materials for offset printing plates are provided either by the consumer directly or by the manufacturer of precoated printing plates on one or both sides with a light-sensitive layer (copying layer), with the aid of which a printing image is generated photomechanically.
• the support carries the printing image areas and at the same time forms the hydrophilic background for the lithographic printing process in the non-image areas (non-image areas).
• Aluminum, steel, copper, brass or zinc, but also plastic films or paper can be used as the base material for such layers. These raw materials are processed through suitable operations such as e.g. Grain, matt chrome plating, surface oxidation and / or application of an intermediate layer are converted into layer supports for offset printing plates.
• Aluminum, which is probably the most frequently used base material for offset printing plates today, is roughened on the surface by known methods by dry brushing, wet brushing, sandblasting, chemical and / or electrochemical treatment. To increase the abrasion resistance, the roughened substrate can be subjected to an anodizing step to build up a thin oxide layer.
• DE-B 10 56 931 describes the use of water-soluble, linear copolymers based on alkyl vinyl ethers and maleic anhydrides in light-sensitive layers for printing plates.
• these copolymers those in which the maleic anhydride component has not been reacted with, or more or less completely, with ammonia, an alkali metal hydroxide or an alcohol are particularly hydrophilic.
• DE-B 10 91 433 describes the hydrophilization of printing plate support materials based on metals with film-forming organic polymers such as polymethacrylic acid or sodium carboxymethyl cellulose or
• water-soluble polyfunctional amino-urea-aldehyde synthetic resins or sulfonated urea-aldehyde synthetic resins are first used, which are in a water-insoluble state on the metal support be cured.
• the hydrophilic layer on a printing plate support material according to DE-C 21 07 901 is formed from a water-insoluble hydrophilic acrylate or methacrylate homopolymer or copolymer with a water absorption of at least 20% by weight
• DE-A 23 08 1 96 discloses hydrophilizing roughened and anodized aluminum printing plate supports with ethylene or methyl vinyl ether / maleic anhydride copolymers, polyacrylic acid, carboxymethyl cellulose, sodium poly (vinyl benzene) 2,4-disulfonic acid) or polyacrylamide
• the layer weight of the hydrophilic adhesive layer on cellulose ether is 0.2 to 1.1 mg / dm 2 , an equal layer weight is also given for the water-soluble salts .
• the mixture of cellulose ether and salt is applied to the support in aqueous solution, optionally with the addition of an organic solvent and / or a surfactant.
• hydrophilizing agents for printing plate support materials according to US Pat. No. 4,049,746 contain acidic reaction products made from water-soluble polyacrylic resins with carboxyl groups and polyalkyleneimine-urea-aidehyde resins.
• GB-A 1 246 696 describes hydrophilic colloids such as hydroxyethylceliulose, polyacrylamide, polyethylene oxide, polyvinylpyrrolidone, starch or gum arabic as hydrophilizing agents for anodized aluminum printing plate supports.
• SU-A 647 142 uses a copolymer of acrylamide and vinyl monomers for the hydrophilization of offset printing plates.
• DE-C 10 91 433 describes a process for the aftertreatment of offset printing plate supports with polymers of methacrylic acid, methyl vinyl ether and maleic anhydride.
• DE-A 29 47 708 describes u.a. Ni salt solutions of acrylamide and acrylic acid as well as acrylamide and vinyl pyrrolidone.
• the object of the invention is therefore to produce substrates for offset printing plates with good hydrophilization properties that they are equally suitable as supports for positive, negative or electrophotographic photosensitive layers without reducing the shelf life, reactions between the hydrophilizing agent and the photosensitive layer occur or that Shift liability is reduced.
• the invention is based on a plate, film or tape-shaped carrier material for offset printing plates consisting of optionally pretreated aluminum or one of its alloys, which has a hydrophilic coating of a phosphonic acid compound on at least one side.
• the hydrophilic coating consists of a) a polymer of acrylamidoisobutylenephosphonic acid or b) a copolymer of acrylamide and acrylamidoisobuylenephosphonic acid or c) a salt of a) or b) with at least one divalent metal cation.
• the metal cations are generally used in the form of their salts with mineral acid anions or as acetates; the divalent, trivalent or tetravalent, in particular the divalent, are preferred.
• the cations are in particular V 5+ , Bi 3+ , Al 3+ , Fe 3+ , Zr 4+ , Sn 4+ , Ca 2+ , Ba 2+ , Sr 2+ , Ti 3+ , Co 2+ , Fe 2+ , Mn 2+ , Ni 2+ , Cu 2+ , Zn 2+ or Mg 2+ ions.
• reaction products can be prepared in a simple manner in aqueous solution at temperatures from 20 to 100 ° C., preferably at 25 to 40 ° C.
• the metal salt is slowly added dropwise to the aqueous polymer solution, dissolved in water or, if necessary, dissolved in dilute mineral acid. This leads to the immediate conversion of the reaction components to the previously described products.
• the rapid onset of reaction is shown - depending on the metal cation used - in the immediately changing color of the solution or through the formation of precipitation.
• the products can be precipitated by neutralizing the reaction solution with dilute alkali hydroxide or ammonia solutions, the unreacted starting products remaining in the solution.
• the yields of these reactions are above 90%.
• acid forms of the polymers described it is also possible to use their salt forms with a monovalent cation such as sodium or ammonium salt.
• the aqueous solutions of the copolymers are used in concentrations of 0.02 to 5%, preferably in concentrations of 0.1 to 1%.
• the isolated and dried reaction products are preferably in 0.1 to 10%, in particular 0.5 to 3%, mineral acids, preferably phosphoric acid, in concentrations of 0, 05 to 5%, especially in concentrations of 0.1 to 1%, dissolved
• the treatment of these substrates with the solutions is expediently carried out by dipping formats or by passing the substrate tape through a bath of these solutions. Temperatures of 20 to 95 ° C., preferably of 25 to 60 ° C. and residence times of 2 seconds to 10 minutes, preferably of 10 seconds to 3 minutes, are found to be the most favorable for practical use. An increase in the bath temperature accelerates the chemisorption of the copolymers and the polymer-metal complexes on the substrate. This makes it possible, particularly in the case of continuous strip treatment, to significantly reduce the residence times.
• the immersion treatment is then advantageously followed by a rinsing step with water. The substrate treated in this way is then expediently dried at temperatures from 110 to 130.degree.
• the treatment of the aluminum substrate with the salts of the copolymers can also be carried out as a two-hour process.
• the substrate is immersed, for example, in a 0.01 to 10%, preferably 0.1 to 5%, aqueous solution of the starting polymer.
• the substrate can then be transferred to a second bath without prior rinsing or drying. which contains a 0.1% to saturated, preferably up to 10% aqueous salt solution with the polyvalent metal ions listed above.
• the rinsing and drying is carried out as in the one-step process.
• the reaction products described above are formed on the substrate during the treatment.
• This process variant can also be used to apply the reaction products of trivalent metal ions which are poorly soluble in strongly acidic media to the substrate.
• the support materials according to the invention thus produced can then be coated with various light-sensitive layers for the production of offset printing plates.
• the method according to the invention can also be applied to other aluminum alloys.
• the aluminum support materials for printing plates which are very common in practice, are generally mechanically (e.g. by brushing and / or with abrasive treatments), chemically (e.g. by etching agents) or electrochemically (e.g. Roughened, for example by AC treatment in aqueous HCI or HNO 3 solutions)
• Aluminum printing plates with electrochemical roughening are used in particular for the present invention.
• the process parameters in the roughening stage are in the following ranges: the temperature of the electrolyte is between 20 and 60 ° C, the active ingredient (acid, set concentration between 5 and 100 g / l, the current density between 15 and 130 A / dm ', the residence time between 10 and 100 sec and the electrolyte flow rate on the surface of the workpiece to be treated between 5 and 100 cm / sec; alternating current is usually used as the type of current, but they are also modified Stromar like alternating current with different amplitudes of the current strength for the anode and cathode current possible.
• the average roughness depth R z of the roughened surface is in the range from about 1 to 15 ⁇ m, in particular in the range from 4 to 8 ⁇ m.
• the roughness depth is determined in accordance with DIN 4768 (in the version from October 1970).
• the roughness depth R z is then the arithmetic mean of the single roughness depths of five adjacent single measuring strains.
• the entraining depth is defined as the distance between two parallels to the middle line, which touch the roughness profile at the highest or lowest point within the individual measuring distances.
• the individual measuring section is the fifth part of the length of the part of the roughness profile which is used directly for evaluation and is projected perpendicularly onto the middle line.
• the middle line is the line parallel to the general direction of the roughness profile from the shape of the geometrically ideal profile, which flattened the roughness profile in such a way that the sum of the material-filled areas above it and the material-free areas below it are the same.
• Direct current is preferably used for the anodic oxidation, however alternating current or a combination of these types of current (eg direct current with superimposed alternating current) can also be used.
• the layer weights of aluminum oxide range from 1 to 10 g / m 2 , corresponding to a layer thickness of approximately 0.3 to 3.0 ⁇ m.
• all layers are suitable as light-sensitive layers which, after exposure, optionally with a subsequent development and / or fixation, provide an image-like area from which printing can take place. They are either applied by the manufacturer of presensitized printing plates or directly by the consumer on one of the usual carrier materials
• photoconductive layers such as are described, for example, in DE-C 11 17 391, 15 22 497, 15 72 312, 23 22 0 4 6 and 23 22 0 4 7, on the support materials, as a result of which highly light-sensitive, electrophotographic Layers arise.
• the coated offset printing plates obtained from the carrier materials according to the invention are developed in a known manner by imagewise exposure or irradiation and washing out the non-image areas with a developer kler, preferably an aqueous developer solution, transferred to the desired printing form.
• a developer kler preferably an aqueous developer solution
• offset printing plates, the base carrier materials of which have been treated according to the invention have a significantly lower color haze and improved hydrophilicity compared to plates which have been treated with homopolymeric acrylamide, with polymeric vinylphosphonic acid or only with hot water.
• the adhesion of the light-sensitive layer to the surface of the support was also better in the samples treated according to the invention than in the comparison samples.
• a bright rolled aluminum strip (DIN material no. 3.0255) with a thickness of 0.3 mm is degreased with an aqueous alkaline 2% pickling solution at an elevated temperature of around 50 to 70 ° C.
• the electrochemical roughening of the aluminum surface takes place with alternating current and in an electrolyte containing HNO 3 ; a surface roughness with an R 2 value of 6 ⁇ m is obtained.
• the subsequent anodic oxidation is carried out in an electrolyte containing sulfuric acid in accordance with the process described in DE-A 28 11 396; the oxide weight is about 3.0 g / m 2 .
• a carrier produced in this way is designated by the number 1 in Tables 2 and 3
• the aluminum strip prepared in this way is then passed through a 60 ° C. bath from a 0.5% solution which contains one of the polymers according to the invention or one of the comparison substances (N1 to NV13).
• the compositions of these solutions are listed in Table 1.
• the residence time in the bath is 30 seconds.
• the excess solution is then removed with tap water in a rinsing step and the strip is dried with hot air at temperatures between 100 and 130 ° C.
• a bright rolled aluminum strip (DIN material no. 3.0515) with a thickness of 0.3 mm is degreased with an aqueous alkaline 2% pickling solution at an elevated temperature of around 50 to 70 ° C.
• the electrochemical roughening of the aluminum surface takes place with alternating current and in an electrolyte containing hydrochloric acid; a surface roughness with an R z value of 6 ⁇ m is obtained.
• the subsequent anodic oxidation is carried out in an electrolyte containing sulfuric acid in accordance with the process described in DE-A 28 11 396; the oxide weight is about 3.0 g / m 2 .
• a carrier produced in this way is designated in Table 2 and 3 with the number 2.
• the aluminum strip prepared in this way is then passed through a 50 ° C. bath from a 0.5% strength solution which contains one of the polymers according to the invention or one of the comparison substances (N1 to NV13).
• the compositions of these solutions are listed in Table 1.
• a carrier produced in this way is designated by the number 3 in Tables 2 and 3.
• the carriers prepared in this way are immersed in a 60 ° C. bath of an aqueous solution of 0.4% of one of the polymers listed in Table 1 under N1 to NV13.
• the residence time in the bath is 60 seconds.
• the excess solution is then desalted in a rinsing step Water is removed and the carrier is air-dried
• Carriers from Example A2 are immersed in a 0.2% solution of the preparations N1 to NV12 (Table 1) at 40 ° C.
• the carriers are shaded as an anode and treated with direct current at 10 V for 20 seconds.
• the current falls off during this treatment initially 3 A / dm 2 to 0.2 A / dm 2 .
• the excess solution is then removed in a rinsing step with deionized water, and the supports are dried in air.
• Table 3 lists the supports thus produced and the results of the measurements described below
• the test is carried out using wetting angle measurements against a drop of water.
• the angle is determined between the carrier surface and a tangent placed through the point of contact of the drop; it is generally between 0 ° and 90 °. The smaller the angle, the better the wetting.
• the information in column 5 of Table 2 relates to these contact angle measurements.
• the carriers are dried as described under 3.
• the carriers are dried as described under 3.
• Table 2 shows that the products according to the invention are better than the prior art in many properties, but not worse in none.
• Table 3 shows that the electrochemically aftertreated supports have correspondingly good values as in Table 2, the values for the zincate test in particular being still improved.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Printing Plates And Materials Therefor (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

Applications Claiming Priority (2)

Publications (3)

Family

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Family Applications (1)

Country Status (9)

Cited By (7)

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• 1985
  • 1985-02-08 DE DE19853504331 patent/DE3504331A1/de not_active Withdrawn
• 1986
  • 1986-01-28 DE DE8686101090T patent/DE3670804D1/de not_active Expired - Fee Related
  • 1986-01-28 EP EP86101090A patent/EP0190643B1/fr not_active Expired - Lifetime
  • 1986-02-03 CN CN86101022A patent/CN1010897B/zh not_active Expired
  • 1986-02-05 CA CA000501187A patent/CA1299007C/fr not_active Expired - Fee Related
  • 1986-02-06 ZA ZA86876A patent/ZA86876B/xx unknown
  • 1986-02-06 AU AU53280/86A patent/AU5328086A/en not_active Abandoned
  • 1986-02-06 ES ES551694A patent/ES8705981A1/es not_active Expired
  • 1986-02-07 BR BR8600541A patent/BR8600541A/pt unknown
  • 1986-02-07 JP JP61024266A patent/JPS61182988A/ja active Pending

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