Electrolytic oxidation-free metal printing plate base and application thereof

Abstract

The invention belongs to the technical field of printing, and relates to an electrolytic oxidation-free metal printing plate base and application thereof, the electrolytic oxidation-free metal printing plate base comprises a metal base material and a super-hydrophilic layer coated on the metal base material; the contact angle of the metal base material in air and water is smaller than or equal to 10 degrees, and the binding force of the super-hydrophilic layer and the metal base material is larger than or equal to 2 N / 2 cm. The metal printing plate base does not need electrolysis, oxidation and other treatment processes in a traditional production process, the cost is greatly saved, the consumption of water and electricity is reduced, and emission of waste acid, waste alkali and other waste chemicals is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of printing, and relates to an electrolytic oxidation-free metal printing plate substrate and application thereof. Background Art

[0002] Offset printing has the advantages of high printing quality, high production efficiency, mature technology, suitability for large-scale production, good cost-effectiveness, and strong adaptability. It is still the most important printing method. The annual global use of offset printing plates exceeds 500 million square meters.

[0003] Offset printing uses the fact that oil and water are immiscible, and the image part of the offset printing plate is oleophilic, while the non-image part is hydrophilic. At present, the base material of the offset printing plate is aluminum or aluminum alloy. In order to increase the hydrophilicity of the aluminum plate base, a series of chemical treatments such as electrolytic oxidation sealing are required to form a porous aluminum oxide grain structure, so that the non-image part of the printing plate has good hydrophilicity and water retention, while improving the bonding strength between the plate base and the photosensitive resin layer and improving the printing durability.

[0004] However, a large amount of electricity is required during the chemical treatment of aluminum substrates, with more than 0.5 kWh consumed to produce 1 square meter of substrate. In addition, a large amount of waste acid, waste alkali and other waste liquids are generated during the production process, causing a great impact on the environment.

[0005] In order to improve these problems in the production of offset printing plate base, some solutions have been proposed, but there are still certain defects.

[0006] In Chinese patent CN103587272A, a large amount of organic solvent is required for the hydrophilic layer, which will cause VOC emissions during the drying process and pollute the environment; and because most of the cross-linking agents selected are not hydrophilic enough, the problem of dirt is prone to occur during printing, affecting the printing quality.

[0007] In Chinese patent CN105313517B, the hydrophilic layer mainly relies on hydrophilic oxide particles. However, the hydrophilicity of these oxides is not enough. If there is no special structure, the contact angle with water is generally large. During the printing process, the water-ink balance is slow, the print quality is poor, and the effect of saving water, ink and waste paper cannot be achieved. Summary of the invention

[0008] The present invention provides a metal printing plate substrate free of electrolytic oxidation, which does not require electrolysis, oxidation and other treatment processes of traditional production processes, greatly saves costs, reduces the use of water and electricity, and avoids the discharge of waste acid, waste alkali and other waste chemicals.

[0009] In order to achieve the above technical purpose, the technical solution adopted by the present application is: an electrolytic oxidation-free metal printing plate substrate, comprising a metal substrate and a super-hydrophilic layer coated on the metal substrate;

[0010] The contact angle between the metal substrate and water in air is ≤10°, and the bonding force between the super hydrophilic layer and the metal substrate is ≥2N / 2cm.

[0011] As an improved technical solution of the present application, the metal substrate is an aluminum plate, an iron plate, a zinc plate, a copper plate or an alloy thereof.

[0012] As an improved technical solution of the present application, the super hydrophilic layer is achieved by coating the aqueous emulsion on the metal substrate;

[0013] The aqueous emulsion is composed of the following substances in parts by weight:

[0014] 4-15 parts by weight of hydrophilic macromolecular organic matter

[0015] Hydrophilic inorganic substance 1-10 parts by weight

[0016] Emulsifier 0.1-2 parts by weight

[0017] Water 82.2-89 parts by weight;

[0018] The hydrophilic macromolecular organic substance is one or more of natural cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, polymethyl methacrylate, polyvinyl alcohol, polyacrylic acid, polyacrylate, polyacrylamide and modified compounds thereof in any weight ratio;

[0019] The hydrophilic inorganic substance is one or more of aluminum oxide, silicon oxide, titanium oxide and zinc oxide in any weight ratio;

[0020] The emulsifier is one of sodium dodecylbenzene sulfonate, calcium dodecylbenzene sulfonate, sodium dodecyl sulfate, gelatin, and gum arabic, or several of them in any weight ratio.

[0021] As an improved technical solution of the present application, the aqueous emulsion needs to be heated at a temperature of 50-200° C. for 30 seconds to 5 minutes during the curing process.

[0022] As an improved technical solution of the present application, the thickness of the super hydrophilic layer is 0.3g / ㎡-5g / ㎡.

[0023] Another object of the present application is to provide an application of an electrolytic oxidation-free metal printing plate substrate, which can be applied to offset printing plates of PS plates, CTcP plates, thermal CTP plates, violet laser CTP plates or processing-free CTP plates.

[0024] Beneficial Effects

[0025] The contact angle between the metal printing plate substrate and water described in the technical solution of the present application is ≤10°, and the bonding force between the super-hydrophilic layer and the metal substrate is ≥2N / cm. The super-hydrophilic layer is formed by emulsion solidification and has the characteristics of acid resistance, alkali resistance, organic solvent resistance, wear resistance and super-hydrophilicity. The metal printing plate substrate does not require electrolysis, oxidation and other treatment processes of traditional production processes, which greatly saves costs, reduces the consumption of water and electricity, and avoids the discharge of waste acid, waste alkali and other waste chemicals.

[0026] In practical application, the metal printing plate substrate of the present invention has the characteristic of super hydrophilicity, and the plate material using the substrate has good hydrophilicity, which accelerates the water-ink balance in the printing process and reduces the water consumption in the printing process.

[0027] After the water-based emulsion is baked and cured, the coating has a strong bonding force with the aluminum plate base, which improves the stability and durability of the plate.

[0028] Compared with the surface of the traditional electrolytic oxidation substrate, the substrate surface is smoother, the edges of the formed dots are sharper, and the image quality is better.

[0029] The CTP plate material using the plate base of the present invention has good hydrophilicity of the non-image and text part when it is printed on the machine, and the water-ink balance is faster during the printing process, which can reduce the amount of water by more than 30% and the amount of ink by more than 20%, and reduce waste paper by more than 50% when starting the machine, thereby reducing production costs and being more environmentally friendly. DETAILED DESCRIPTION

[0030] The technical solution of the present application is clearly and completely described below in conjunction with specific implementation methods.

[0031] An electrolytic oxidation-free metal printing plate substrate comprises a metal substrate and a super-hydrophilic layer coated on the metal substrate; the contact angle of the metal substrate with water in air is ≤10°, and the bonding force between the super-hydrophilic layer and the metal substrate is ≥2N / 2cm.

[0032] The most basic printing principle in offset printing plates is to use the fact that oil and water are immiscible, the non-image part (blank base) is hydrophilic, and the image part is oleophilic, so that the ink and water are kept in balance on the printing plate to achieve the transfer of text and images. The hydrophilicity of the base is crucial to the performance of the plate. When the contact angle between the base and water in the air is ≤10°, the base can quickly retain water, thereby achieving ink-water balance faster, making the quality of the printed product higher and saving paper wasted in the ink-water balance process.

[0033] Offset printing plates need to print tens to hundreds of thousands of copies, so the bonding between the super-hydrophilic layer and the base must be strong enough to meet the needs of long printing runs.

[0034] In some embodiments, the metal substrate is an aluminum plate, an iron plate, a zinc plate, a copper plate or an alloy thereof. In order to form a porous grain structure, the traditional offset printing plate needs to be electrolytically oxidized to achieve a hydrophilic and wear-resistant effect, so an aluminum plate must be used. The electrolytic oxidation-free metal printing plate base of the present invention does not require electrolytic oxidation treatment, has lower requirements on the metal substrate, and commonly used low-cost metal plates can be used.

[0035] As an improved technical solution of the present application, the super hydrophilic layer is achieved by coating the aqueous emulsion on the metal substrate;

[0036] The aqueous emulsion is composed of the following substances in parts by weight:

[0037] 4-15 parts by weight of hydrophilic macromolecular organic matter

[0038] Hydrophilic inorganic substance 1-10 parts by weight

[0039] Emulsifier 0.1-2 parts by weight

[0040] Water 82.2-89 parts by weight;

[0041] The hydrophilic macromolecular organic substance is one or more of natural cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, polymethyl methacrylate, polyvinyl alcohol, polyacrylic acid, polyacrylate, polyacrylamide and modified compounds thereof in any weight ratio;

[0042] The hydrophilic inorganic substance is one or more of aluminum oxide, silicon oxide, titanium oxide and zinc oxide in any weight ratio;

[0043] The emulsifier is one of sodium dodecylbenzene sulfonate, calcium dodecylbenzene sulfonate, sodium dodecyl sulfate, gelatin, and gum arabic, or several of them in any weight ratio. The hydrophilic macromolecular organic matter is wrapped on the surface of the hydrophilic inorganic matter, and under the action of the emulsifier, it is evenly dispersed in water to form an emulsion; after being coated on the surface of the metal substrate, the hydrophilic macromolecular organic matter and the hydrophilic inorganic matter are evenly distributed, ensuring the hydrophilicity and wear resistance of the substrate.

[0044] As an improved technical solution of the present application, the aqueous emulsion needs to be heated at a temperature of 50-200° C. for 30 seconds to 5 minutes during the curing process. The hydrophilic polymer is cured at high temperature to form a firm coating.

[0045] As an improved technical solution of the present application, the thickness of the super hydrophilic layer is 0.3g / ㎡-5g / ㎡, which controls the cost while ensuring the wear resistance of the super hydrophilic coating.

[0046] Another object of the present application is to provide an application of an electrolytic oxidation-free metal printing plate substrate, which can be applied to offset printing plates of PS plates, CTcP plates, thermal CTP plates, violet laser CTP plates or processing-free CTP plates.

[0047] Embodiment 1:

[0048] A 1060 aluminum plate with a thickness of 0.263 mm was selected as the metal substrate. An aqueous emulsion consisting of 4 parts by weight of polyvinyl alcohol (hydrophilic polymer organic matter), 10 parts by weight of aluminum oxide (hydrophilic inorganic matter), 1 part by weight of sodium dodecyl sulfate (emulsifier) ​​and 85 parts by weight of water was evenly coated on the surface of the aluminum plate, and then heated in an oven at 200°C for 5 minutes to solidify it to form a super hydrophilic layer with a thickness of 1 g / ㎡.

[0049] Sample 1 was obtained as described above.

[0050] Embodiment 2:

[0051] A 1060 aluminum plate was selected as the metal substrate with a thickness of 0.263 mm. An aqueous emulsion consisting of 15 parts by weight of hydroxyethyl cellulose (hydrophilic polymer organic matter), 1 part by weight of silicon oxide (hydrophilic inorganic matter), 1.5 parts by weight of sodium dodecylbenzene sulfonate (emulsifier) ​​and 82.5 parts by weight of water was evenly coated on the surface of the aluminum plate, and then heated in an oven at 140°C for 2 minutes to solidify it to form a super hydrophilic layer with a thickness of 1 g / ㎡.

[0052] Sample 2 was obtained as described above.

[0053] Embodiment 3:

[0054] A 1060 aluminum plate was selected as the metal substrate with a thickness of 0.263 mm. An aqueous emulsion consisting of 6 parts by weight of PVA fiber-modified polyacrylate (hydrophilic polymer organic matter), 3 parts by weight of zinc oxide (hydrophilic inorganic matter), 2 parts by weight of gelatin (emulsifier) ​​and 89 parts by weight of water was evenly coated on the surface of the aluminum plate, and then heated in an oven at 145°C for 3 minutes to solidify it to form a super-hydrophilic layer. The thickness of the super-hydrophilic layer is 1 g / ㎡.

[0055] Sample 3 was obtained as described above.

[0056] Embodiment 4:

[0057] A 1060 aluminum plate was selected as the metal substrate with a thickness of 0.263 mm. An aqueous emulsion consisting of 10 parts by weight of polyacrylamide (hydrophilic macromolecular organic matter), 7 parts by weight of titanium oxide (hydrophilic inorganic matter), 0.1 parts by weight of gum arabic (emulsifier) ​​and 82.9 parts by weight of water was evenly coated on the surface of the aluminum plate, and then heated in an oven at 150°C for 3 minutes to solidify it to form a super hydrophilic layer. The thickness of the super hydrophilic layer is 5 g / ㎡.

[0058] Sample 4 was obtained as described above.

[0059] Embodiment 5:

[0060] SPCC cold-rolled steel coil was selected as the metal substrate with a thickness of 0.15 mm. An aqueous emulsion consisting of 5 parts by weight of natural cellulose and 5 parts by weight of hydroxyethyl cellulose (hydrophilic polymer organic matter), 4 parts by weight of aluminum oxide and 3 parts by weight of silicon oxide (hydrophilic inorganic matter), 0.8 parts by weight of calcium dodecylbenzene sulfonate (emulsifier) ​​and 82.2 parts by weight of water was evenly coated on the surface of the aluminum plate, and then heated in an oven at 150°C for 3 minutes to solidify it to form a super hydrophilic layer. The thickness of the super hydrophilic layer is 1 g / ㎡.

[0061] Sample 5 was obtained as described above.

[0062] Comparative Example 1:

[0063] The substrate was made of 1060 aluminum plate, which was treated as follows to obtain a hydrophilic surface.

[0064] (1) Decontamination

[0065] The aluminum plate was decontaminated by soaking it in an aqueous solution of sodium hydroxide and sodium gluconate at 45 degrees Celsius for 30 seconds.

[0066] (2) Electrolysis

[0067] The plate is required to have good oleophilicity for the graphic part and good hydrophilicity for the blank part; the good hydrophilicity of the blank part requires the aluminum plate to be grained so that the blank grained part can store water and not be oleophilic. The grains are formed by electrolysis, with the aluminum plate and graphite as two electrodes, the electrolyte: 13g / L hydrochloric acid solution, 50HZ alternating current, current 80A / d㎡, liquid temperature 30-60℃, electrolysis time 25 seconds, and control Ra=0.45-0.55um.

[0068] (3) Oxidation

[0069] In order to improve the mechanical strength, wear resistance and hydrophilicity of the aluminum plate surface, the aluminum plate surface must be anodized. Use 24% sulfuric acid solution, 45°C temperature, 35 seconds of electrolysis, aluminum ion concentration: 2.3g / L, use direct current, current 3A / d㎡. Control the oxide film 2.7-3.3g / ㎡.

[0070] (4) Sealing

[0071] There are many micropores on the surface of the aluminum plate after electrolysis and anodization. The purpose of sealing is to block these micropores. Sodium silicate aqueous solution is used to soak to achieve hydrophilization and sealing.

[0072] Comparative Sample 1 was obtained as described above.

[0073] Method for testing the contact angle between substrate and water:

[0074] The contact angle between the substrate and water was measured using the OCA contact angle meter from Dataphysics. The substrate was fixed to the OCA contact angle meter, and a drop of water was dropped onto a clean, scratch-free substrate through the instrument. The contact angle of the water drop on the substrate was measured after 10 seconds.

[0075] Super hydrophilic layer and metal substrate bonding strength test method:

[0076] A 2 cm wide PET sheet was bonded to the above substrate using special tire repair glue, and the bonding strength between the super hydrophilic layer and the metal substrate was tested using an electronic peeling tester.

[0077] The performance of the substrate is shown in Table 1:

[0078] Table 1 Plate base performance test

[0079]

[0080]

Claims

1. An electrolytic oxidation-free metal printing plate substrate, characterized in that: It comprises a metal substrate and a super hydrophilic layer coated on the metal substrate; The contact angle between the metal substrate and water in air is ≤10°, and the bonding force between the super hydrophilic layer and the metal substrate is ≥2N / 2cm.

2. The electroless oxidation metal printing plate substrate according to claim 1, characterized in that: The metal substrate is an aluminum plate, an iron plate, a zinc plate, a copper plate or an alloy thereof.

3. The electroless oxidation metal printing plate substrate according to claim 1, characterized in that: The super hydrophilic layer is achieved by coating the aqueous emulsion on the metal substrate; The aqueous emulsion is composed of the following materials in parts by weight: composition: 4-15 parts by weight of hydrophilic macromolecular organic matter Hydrophilic inorganic substance 1-10 parts by weight Emulsifier 0.1-2 parts by weight Water 82.2-89 parts by weight; The hydrophilic macromolecular organic substance is one or more of natural cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, polymethyl methacrylate, polyvinyl alcohol, polyacrylic acid, polyacrylate, polyacrylamide and modified compounds thereof in any weight ratio; The hydrophilic inorganic substance is one or more of aluminum oxide, silicon oxide, titanium oxide and zinc oxide in any weight ratio; The emulsifier is one of sodium dodecylbenzene sulfonate, calcium dodecylbenzene sulfonate, sodium dodecyl sulfate, gelatin, and gum arabic, or several of them in any weight ratio.

4. The electroless oxidation metal printing plate substrate according to claim 3, characterized in that: The curing process of the water-based emulsion requires heating at a temperature of 50-200°C for 30 seconds to 5 minutes.

5. The electroless oxidation metal printing plate substrate according to claim 1, characterized in that: The thickness of the super hydrophilic layer is 0.3 g / ㎡-5 g / ㎡.

6. The use of an electroless oxidation-free metal printing plate substrate according to claims 1-6, characterized in that: The metal printing plate substrate can be applied to offset printing plates of PS plates, CTcP plates, thermal CTP plates, violet laser CTP plates or treatment-free CTP plates.

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