CN109233616B - Composition for aqueous printing plate, coating for aqueous printing plate, method for producing aqueous printing plate, lithographic printing system, and application thereof - Google Patents

Abstract

The invention relates to the field of printing, and discloses a composition for an aqueous printing plate, a coating for the aqueous printing plate, a preparation method of the aqueous printing plate, a lithographic printing system and application of the lithographic printing system. A composition for an aqueous printing plate, wherein the composition comprises 10 to 50 wt% of silicone rubber, 0.01 to 5 wt% of a curing agent, 10 to 60 wt% of alkyl silicone, and 5 to 79.99 wt% of an organic solvent, based on the total weight of the composition. The invention realizes printing by using the water-based printing ink in a lithographic printing mode by adjusting the structure of a printing system and changing the composition of the printing plate, and has the advantages of environmental friendliness, low printing plate cost and resource saving.

Description

Composition for water-based printing plate, coating for water-based printing plate, water-based printing plate and preparation method thereof Lithographic printing system and its application

technical field

The invention relates to the field of printing, in particular to a composition for an aqueous printing plate, a coating for an aqueous printing plate, an aqueous printing plate, a preparation method thereof, and a lithographic printing system and application thereof.

Background technique

The printing industry is one of the most influential industries in China. In 2015, the total output value of China's printing industry reached 1,124.62 billion yuan, ranking second in the world in terms of industrial scale. The main printing method in my country is lithography, which is widely used due to its high printing accuracy and mature related technologies. However, the commonly used lithography often has the problem of polluting the environment. Its pollution to the environment comes from the electrolytic anodization during the preparation of the plate base, which produces a large amount of waste acid and waste alkali, and the development and fixing during plate making. The waste liquid containing harmful chemical components and organic solvents Emissions of volatile organic compounds (VOCs) from printing inks. Optimizing the lithographic printing method and reducing the pollution generated by each link has become a problem that green printing must quickly solve.

Since the annual VOC emissions of printing inks containing organic solvents are nearly hundreds of thousands of tons, which are more harmful to the atmosphere and human body, water-based printing inks are considered as printing inks because of their low VOC emissions, no impact on human health and easy disposal of waste liquids. The key to process greening.

However, at present, the price of gravure or flexo printing plates using water-based printing inks on the market is relatively high, because compared with the independent lithographic printing of printing plates and plate cylinders, gravure or flexo printing plates and printing plates The cylinder is one piece, and the whole is replaced every time the printing plate is replaced. For lithographic printing, the printing plate is combined with the printing plate cylinder every time it is used, and the printing plate can be replaced by simply removing the printing plate from the printing plate cylinder, and the cost is low. However, lithographic printing plates are not suitable for water-based printing inks, because traditional lithographic printing often requires plate cylinders, blanket cylinders and impression cylinders, the length of the ink path is long, and the viscosity of water-based printing plate inks is low. After the 3 rollers, the ink volume is greatly reduced, and the phenomenon of insufficient ink color or no ink often occurs; and the longer the ink path, the more process steps, the higher the operation requirements, the more harmful substances volatilized, and the energy saving is not enough. .

To sum up, the use of traditional lithographic printing systems pollutes the environment, and printing inks containing organic solvents cause a large amount of VOC emissions; while the use of water-based printing inks has low VOC emissions, but the preparation costs of traditional water-based printing inks are high. , Each time the printing plate is replaced, a large waste of resources will be generated; and the ink path length of traditional lithographic printing is long, the process flow steps are many, and the operation is not easy enough. If only the low-contamination water-based printing ink is simply combined with the traditional low-cost lithographic printing plate and the traditional lithographic printing system, when the water-based printing ink is used, the phenomenon of insufficient or no ink in the image and text often occurs.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above-mentioned problems existing in the prior art, provide a composition for water-based printing plates, coatings for water-based printing plates, water-based printing plates and preparation methods thereof and lithographic printing systems and applications thereof. The structure of the printing system, changing the composition of the printing plate, and realizing the use of water-based printing ink for printing in the lithographic printing method have the advantages of environmental friendliness, low printing plate cost and resource saving.

In order to achieve the above object, one aspect of the present invention provides a composition for an aqueous printing plate, wherein, based on the total weight of the composition, the composition contains 10-50 wt % of silicone rubber, 0.01-5 wt % of curing agent, 10-60% by weight of alkyl silicon and 5-79.99% by weight of organic solvent.

The second aspect of the present invention provides a coating for a water-based printing plate, wherein the coating is prepared by curing the above-mentioned composition for a water-based printing plate, the curing temperature is 50-100°C, and the curing time is 0.5-1 day.

A third aspect of the present invention provides a water-based printing plate, wherein the printing plate comprises: a base layer, a primer layer and a graphic layer sequentially stacked on the base layer, wherein the primer layer is the above-mentioned A coating obtained by curing a composition for an aqueous printing plate; the graphic layer is a polymer layer containing a hydrophilic group.

A fourth aspect of the present invention provides a method for preparing the above-mentioned water-based printing plate, the method comprising the following steps:

(1) coating the above-mentioned composition for aqueous printing plate on the base layer and carrying out the first curing to form an undercoat layer;

(2) Coating a hydrophilic group-containing polymer on the primer layer and performing second curing to form a graphic layer.

A fifth aspect of the present invention provides a lithographic printing system, the lithographic printing system includes an ink tank, a doctor blade, a printing plate cylinder, and an impression cylinder; wherein, the above-mentioned water-based printing plate is adhered on the outer surface of the printing plate cylinder, and A splint is arranged for fixing the water-based printing plate; a splint groove is arranged on the impression cylinder;

Among them, the water-based printing plate is immersed in the ink tank to absorb the water-based printing ink, and the excess ink on the water-based printing plate is removed with a scraper; the water-based printing plate that absorbs the water-based printing ink is rotated by rotating the printing plate cylinder to contact the front of the substrate, while rotating the water-based printing plate The impression cylinder contacts the back side of the substrate and exerts pressure to print graphic information on the front side of the substrate; the splint falls into the splint groove with the rotation of the plate cylinder, and then follows the rotation of the plate cylinder. Rotation, the splint leaves the splint groove.

The sixth aspect of the present invention provides an application of the above-mentioned lithographic printing system in water-based printing ink.

Through the above technical solutions, the use of water-based printing inks for printing in lithographic printing is realized without using printing inks containing organic solvents that emit more VOCs, and the water-based printing inks used have low VOC emissions, do not affect human health, and are easy to waste liquid processing, and the printing effect is good, the ink color is full and there is no ink shortage.

Through the above technical solution, the length of the offset printing ink path can be shortened, that is, the printing plate cylinder, the blanket cylinder and the impression cylinder in the prior art are replaced by the printing plate cylinder and the impression cylinder, which reduces the process steps, saves more energy, and reduces the consumption of VOC. emission.

Through the above technical solution, each time the printing plate is replaced, only the printing plate on the outer surface of the printing plate cylinder needs to be replaced, and there is no need to replace the whole, which saves resources and greatly reduces costs.

Description of drawings

FIG. 1 is a schematic diagram of the structure of a lithographic printing system.

Description of reference numerals

1. Ink tank 2. Scraper 3. Plate cylinder

4. Water-based printing plate 5. Impression cylinder 6. Plywood

7. Plywood groove 8. Substrate

Detailed ways

The endpoints of ranges and any values disclosed herein are not limited to the precise ranges or values, which are to be understood to encompass values proximate to those ranges or values. For ranges of values, the endpoints of each range, the endpoints of each range and the individual point values, and the individual point values can be combined with each other to yield one or more new ranges of values that Ranges should be considered as specifically disclosed herein.

The present invention provides a composition for an aqueous printing plate, wherein, based on the total weight of the composition, the composition contains 10-50 wt % of silicone rubber, 0.01-5 wt % of a curing agent, 10-60 wt % % by weight of alkyl silicon and 5 to 79.99% by weight of organic solvent.

Further, based on the total weight of the composition, the composition may contain 10-50 wt % of silicone rubber, 0.01-5 wt % of curing agent and 10-60 wt % of alkylsilyl silicon according to requirements. , the balance is organic solvent.

In the present invention, the viscosity of the silicone rubber is 1000-80000 centipoise. This viscosity is the viscosity at normal temperature.

In the present invention, the curing agent is one of ethyl orthosilicate, silicon nitride polymer, butyltin dilaurate, dibutyltin dilaurate, hydrogen-containing silicone oil and chloroplatinic acid.

In the present invention, the alkyl silicon is shown in formula (1):

Wherein, in the formula, R ₁ , R ₂ , R ₃ and R ₄ can each independently be a C ₁ -C ₁₀ alkyl or aryl group, preferably, R ₂ , R ₃ and R ₄ are the same, for example, R ₂ , Both R ₃ and R ₄ are C ₁ , C ₂ , C ₃ , C ₅ , C ₇ , and C ₁₀ . Specifically, the alkyl silicon can be represented by formula (2), formula (3), and formula (4).

In the present invention, the organic solvent may be selected from at least one of alcohols, ketones, ethers, esters and hydrocarbons.

In a preferred case, the alcohol is selected from a monohydric alcohol, a dihydric alcohol or a trihydric alcohol below _C5 , for example, it can be ethylene glycol, ethanol, propylene glycol, and glycerol.

In a preferred case, the ketone is at least one of acetone, butanone, cyclohexanone, N-methylpyrrolidone and N-ethylpyrrolidone.

In a preferred case, the ether is ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol At least one of monoethyl ether, propylene glycol dimethyl ether and propylene glycol diethyl ether.

In a preferred case, the ester is at least one of ethyl acetate, methyl acetate, ethyl formate, butyl formate and propylene glycol methyl ether acetate.

In a preferred case, the hydrocarbon is at least one of n-heptane, n-hexane, toluene and xylene.

The present invention also provides a coating for a water-based printing plate, wherein the coating is prepared by curing the above-mentioned composition for a water-based printing plate, and the curing temperature and time can be determined according to the needs, without any special limitation.

In the preferred case of the present invention, the curing temperature is 50-100°C, for example, it can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C and any two of these values in the range formed by any value.

In a preferred case of the present invention, the curing time is 0.5 to 1 day, for example, 0.5 day, 0.6 day, 0.8 day, 1 day, and any value in the range constituted by any two of these values.

The present invention also provides a water-based printing plate, which comprises: a base layer, a primer layer and a graphic layer sequentially stacked on the base layer, wherein the primer layer is for the above-mentioned water-based printing plate A coating obtained by curing the composition; the graphic layer is a polymer layer containing a hydrophilic group.

In the present invention, the base layer may be a base layer formed by a conventional substrate in the field, and the substrate may be an aluminum plate, an aluminum alloy plate, a polyethylene terephthalate (PET) plate, or a polycarbonate plate.

In the present invention, the curing conditions of the primer layer can be the same as the curing conditions of the above-mentioned water-based printing plate coating, and the specific curing conditions are not particularly limited for the purpose of achieving curing.

In the present invention, the hydrophilic group-containing polymer layer is composed of polyethylene glycol, polyethylene glycol formal, polyethylene glycol butyral, polyacrylic acid, polymethyl acrylate, polyethyl acrylate , at least one of polymethacrylic acid, polybutylmethacrylate and polyurethane is formed.

In the present invention, the base layer is a carrier.

In the present invention, the undercoat layer is a hydrophobic printing ink.

In the present invention, the graphic layer is hydrophilic printing ink.

In the present invention, the thickness of the base layer is 0.15-0.60 mm, preferably 0.20-0.40 μm.

In the present invention, the coating thickness of the primer layer is 5-100 μm, preferably 10-80 μm, more preferably 10-50 μm.

In the present invention, the thickness of the graphic layer is 5-1000 μm, preferably 10-800 μm, more preferably 10-500 μm.

The present invention also provides a method for preparing the above-mentioned water-based printing plate, which comprises the following steps:

(1) coating the above-mentioned composition for aqueous printing plate on the base layer and carrying out the first curing to form an undercoat layer;

(2) Coating a hydrophilic group-containing polymer on the primer layer and performing second curing to form a graphic layer.

In the present invention, in step (1), the curing conditions of the primer layer can be the same as the curing conditions of the above-mentioned coating for water-based printing plates, so as to be able to achieve curing, there is no special curing conditions for the specific curing conditions. limit.

In the present invention, in step (2), the formation method of the graphic layer is a conventional formation method in the field, which may be but not limited to inkjet printing and photosensitive imaging methods. Before inkjet printing or coating the photosensitive layer, the primer layer is subjected to plasma sputtering treatment for 100-300 seconds, and after inkjet printing or photosensitive imaging, it is cured at 100-200°C. Ink jet printing or photoimaging methods are conventional in the art.

In the present invention, in step (2), the curing conditions of the primer layer include the purpose of being able to be cured, and are not particularly limited. In a preferred embodiment of the present invention, the curing temperature is 100 to 200° C., and the curing time is 0.5 to 2 hours.

The present invention also provides a lithographic printing system, as shown in FIG. 1 , the lithographic printing system includes an ink tank 1 , a doctor blade 2 , a printing plate cylinder 3 , and an impression cylinder 5 , wherein, on the outer surface of the printing plate cylinder 3 The above-mentioned water-based printing plate 4 is attached, and a splint 6 is arranged to fix the water-based printing plate 5 ; a splint groove 7 is arranged on the impression cylinder 5 .

In the present invention, the ink tank is used to hold water-based printing ink for printing.

In the present invention, the water-based printing plate 4 is immersed in the ink tank 1 to absorb the water-based printing ink, and the excess ink on the water-based printing plate 4 is removed with a scraper 2; The front side of the substrate 8, while rotating the impression cylinder 5 to contact the back side of the substrate 8 and apply pressure, so that graphic information is printed on the front side of the substrate 8; into or out of the clamping plate groove 7 , and then with the rotation of the printing plate cylinder 3 , the clamping plate 6 leaves the clamping plate groove 7 .

According to an embodiment of the present invention, the graphic layer of the water-based printing plate 4 absorbs the water-based printing ink for printing graphic information, and the undercoat layer of the water-based printing plate 4 does not absorb the water-based printing ink.

In a preferred situation of the present invention, the scraper 2 scrapes the excess ink on the aqueous printing plate 4 back into the ink tank 1 .

In the present invention, the material of the scraper can be metal or non-metal.

The metal may be one of stainless steel, aluminum, copper, and aluminum alloys.

The non-metal can be one of polyisoprene, silicone rubber, polyurethane, epoxy resin, polyester, polyvinyl chloride and polytetrafluoroethylene.

In the present invention, the blade thickness of the scraper may be 0.1-1 mm, preferably 0.1-0.5 mm, more preferably 0.1-0.25 mm, and more preferably 0.15-0.2 mm.

In the preferred case of the present invention, the scraper 2 is pneumatically controlled, which is safer and more reliable.

In a preferred situation of the present invention, the size of the splint groove 7 matches the size of the splint 6 , and the depth of the splint groove 7 is consistent with the height of the splint 6 . Because the splint 6 forms a bulge after fixing the water-based printing plate 4 on the plate cylinder 3, when the bulge on the plate cylinder 3 rotates to the impression cylinder, it is ensured that the plate cylinder 3 and the impression cylinder 5 are mutually smooth. pass.

In the preferred case of the present invention, the plate cylinder 3 and the impression cylinder 5 rotate at the same time, the clamping plate 6 falls into the clamping plate groove 7 with the rotation of the printing plate cylinder 3, and then the clamping plate 6 leaves the clamping plate with the rotation of the printing plate cylinder 3. Groove 7.

The invention also provides the application of the above-mentioned lithographic printing system in the water-based printing ink, and the printed product has full ink color and no ink shortage phenomenon.

The present invention will be described in detail below by means of examples.

In the following examples,

The water-based printing ink was purchased from the gravure ink of Tianjin Yunlong Ink Co., Ltd.

Printed on a quadruple press (Heidelberg, Germany), and the run-time is calculated.

The line resolution of the product is detected by X-Rite's iCPlate 2 model plate detector.

Example 1

Examples 1-5 illustrate the method of the present invention.

(1) Preparation of water-based printing plates

A composition for preparing an aqueous printing plate: based on the total weight of the composition, the composition contains 10% by weight of a silicone rubber with a viscosity of 80,000 centipoise, 0.01% by weight of butyltin dilaurate, 60% by weight of a silicone rubber of the formula ( 2) alkyl silicon shown and 29.99% by weight of N-methylpyrrolidone,

A four-part aluminum alloy plate with a thickness of 0.20 mm was prepared as the base layer, and the above-mentioned composition for aqueous printing plates was coated thereon with a coating thickness of 10 μm, and cured at 50° C. for 1 day to obtain an undercoat layer. Then, the undercoat layer was subjected to plasma sputtering treatment for 100 seconds, and a graphic layer formed of polyethylene glycol formal was formed by inkjet printing. The graphic layer had a thickness of 500 μm, and was cured at 100° C. for 2 hours. An aqueous printing plate 4 was obtained.

(2) Install the lithography system shown in Figure 1

The lithographic printing system includes an ink tank 1, a doctor blade 2, a printing plate cylinder 3, and an impression cylinder 5; wherein, the water-based printing plate 4 prepared in step (1) is attached to the outer surface of the printing plate cylinder, and a splint 6 is provided for For fixing the water-based printing plate 4; on the impression cylinder 5, a splint groove 7 and a substrate 8 are arranged. Among them, the material of the scraper is stainless steel, the thickness is 0.15mm, and the scraper 2 is pneumatically controlled.

(3) Printing operation

Immerse the water-based printing plate 4 into the ink tank 1 to absorb the water-based printing ink, remove the excess ink on the water-based printing plate 4 with a scraper 2, and scrape the excess ink back into the ink tank 1; rotating the printing plate cylinder 3 will absorb the water-based printing ink. The water-based printing plate 4 of the printing ink contacts the front side of the white paper, and simultaneously rotates the impression cylinder 5 to contact the back side of the white paper and applies pressure, so that graphic information is printed on the front side of the white paper; the splint 6 follows the printing plate. The rotation of the cylinder 3 falls into the clamping plate groove 7 , and then with the rotation of the printing plate cylinder 3 , the clamping plate 6 leaves the clamping plate groove 7 .

The printing endurance of the water-based printing plate and the line resolution of the printed product were measured, and the results are shown in Table 1 below.

Example 2

(1) Preparation of water-based printing plates

The composition for preparing an aqueous printing plate: based on the total weight of the composition, the composition contains 50% by weight of a silicone rubber with a viscosity of 1000 centipoise, 5% by weight of butyltin dilaurate, 10% by weight of a compound such as formula ( 3) shown alkyl silicon and 35% by weight of ethylene glycol,

An aluminum plate with a thickness of 0.4 mm was prepared as a base layer, and the composition for an aqueous printing plate was coated thereon with a thickness of 50 μm and cured at 100° C. for 1 day to obtain an undercoat layer. Then, the undercoat layer was treated by plasma sputtering for 200 seconds, and then a graphic layer formed of polyethylene glycol butyral was formed by inkjet printing. An aqueous printing plate 4 was obtained.

(2) Install the lithography system shown in Figure 1

According to the method of Example 1, the difference is that the material of the scraper is silicone rubber, and the thickness is 0.2 mm.

(3) Printing operation

The printed product was prepared according to the method of Example 1.

The printing endurance of the water-based printing plate and the line resolution of the printed product were measured, and the results are shown in Table 1 below.

Example 3

(1) Preparation of water-based printing plates

A composition for preparing an aqueous printing plate: based on the total weight of the composition, the composition contains 40% by weight of silicone rubber with a viscosity of 15,000 centipoise, 3% by weight of ethyl orthosilicate, 10% by weight of The alkyl silicon shown in (4) and 47% by weight of ethylene glycol,

A quartet polycarbonate plate was prepared as a base layer with a thickness of 0.3 mm, on which the composition for an aqueous printing plate was coated with a coating thickness of 30 μm, and cured at 60° C. for 0.5 days. Then, a graphic layer formed of polyacrylic acid is formed by a photosensitive imaging method, the graphic layer has a thickness of 10 μm, and is cured at 150° C. for 1.5 hours. An aqueous printing plate 4 was obtained.

(2) Install the lithography system shown in Figure 1

According to the method of Example 1, the difference is that the material of the scraper is polyisoprene, and the thickness is 0.15 mm.

(3) Printing operation

The printed product was prepared according to the method of Example 1.

The printing endurance of the water-based printing plate and the line resolution of the printed product were measured, and the results are shown in Table 1 below.

Example 4

According to the method of Example 1, the difference is that the thickness of the base layer is 0.15 mm, the coating thickness of the primer layer is 5 μm, and the thickness of the graphic layer is 5 μm.

The printed product was prepared according to the method of Example 1.

The printing endurance of the water-based printing plate and the line resolution of the printed product were measured, and the results are shown in Table 1 below.

Example 5

According to the method of Example 1, the difference is that the thickness of the base layer is 0.60 mm, the coating thickness of the primer layer is 100 μm, and the thickness of the graphic layer is 1000 μm.

The printed product was prepared according to the method of Example 1.

The printing endurance of the water-based printing plate and the line resolution of the printed product were measured, and the results are shown in Table 1 below.

Comparative Example 1

According to the method of Example 1, the difference is: based on the total weight of the composition for aqueous printing plates, the composition contains 5% by weight of silicone rubber with a viscosity of 500 centipoise, 10% by weight of butyltin dilaurate, 80% by weight of alkyl silicon having the structure represented by formula (2) and 5% by weight of N-methylpyrrolidone.

The coating thickness of the primer layer was 5 μm, and the thickness of the graphic layer was 2 μm, which was cured at 120 °C for 0.5 days.

The printing endurance of the water-based printing plate and the line resolution of the printed product were measured, and the results are shown in Table 1 below.

Comparative Example 2

According to the method of Example 1, the difference is: based on the total weight of the composition, the composition contains 60% by weight of silicone rubber with a viscosity of 100,000 centipoise, 0.005% by weight of butyltin dilaurate, 5% by weight of Alkyl silicon having a structure represented by formula (2) and 34.995% by weight of N-methylpyrrolidone.

The coating thickness of the undercoat layer was 80 μm, and the thickness of the graphic layer was 5 μm, and was cured at 120° C. for 0.5 days, and the thickness of the graphic layer was 5 μm, which was cured at 200° C. for 0.45 hours.

The printing endurance of the water-based printing plate and the line resolution of the printed product were measured, and the results are shown in Table 1 below.

Comparative Example 3

On the basis of Example 1, only the water-based printing plate 3 of Example 1 was replaced with a conventional ordinary printing plate for lithographic printing. The printing endurance of the ordinary printing plate and the line resolution of the printed product were measured, and the results are shown in Table 1 below.

Example 4

Using conventional lithographic printing systems, water-based printing inks are used. The printing endurance of the ordinary printing plate and the line resolution of the printed product were measured, and the results are shown in Table 1 below.

Table 1

Numbering Durability (sheets) Line Resolution (μm) Example 1 9900 20 Example 2 11000 10 Example 3 9800 20 Example 4 8000 50 Example 5 7800 60 Comparative Example 1 100 55 Comparative Example 2 65 100 Comparative Example 3 50 150 Comparative Example 4 50 120

It can be seen from the results in Examples and Table 1 that the composition provided by the present invention can be used to form an undercoat layer of an aqueous printing plate, and a lithographic printing system composed of an aqueous printing plate containing the undercoat layer can achieve Using water-based printing ink for printing, in the obtained printing plate graphics, the line resolution can reach 10 μm, the prepared graphics and text information is complete and clear, the ink color is full, and there is no ink shortage phenomenon. At the same time, the printing endurance of the lithographic printing system can reach more than 7800, and it has better printing ability. Comparative Examples 1-4 did not adopt the technical solution of the present invention, and the obtained graphic information could not be clearly distinguished and had poor printing ability.

The technical scheme provided by the present invention realizes the lithographic printing that can use water-based printing ink, avoids the use of printing ink containing organic solvent that emits high VOC, reduces the emission of VOC, and has the advantages of environmental friendliness.

Moreover, by adopting the technical solution of the present invention, lithographic printing can be realized only by using two cylinders, a printing plate cylinder and an impression cylinder, which usually requires a printing plate cylinder, a blanket cylinder and an impression cylinder compared to the existing lithographic printing using ink. , shortens the length of the offset printing ink path, saves the process steps and system components, saves energy, and reduces manufacturing costs.

The preferred embodiments of the present invention have been described above in detail, however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, a variety of simple modifications can be made to the technical solutions of the present invention, including the combination of various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed in the present invention. All belong to the protection scope of the present invention.

Claims (12)

1. An aqueous printing plate, wherein the printing plate comprises: the printing plate comprises a base layer, and a bottom coating layer and an image-text layer which are sequentially stacked on the base layer, wherein the bottom coating layer is a coating layer prepared by curing a composition for the water-based printing plate; the image-text layer is a polymer layer containing hydrophilic groups;

the composition comprises 10-50 wt% of silicon rubber, 0.01-5 wt% of curing agent, 10-60 wt% of alkyl silicon and 5-79.99 wt% of organic solvent based on the total weight of the composition for the water-based printing plate;

the curing agent is at least one of ethyl orthosilicate, silicon nitrogen polymer, butyltin dilaurate, dibutyltin dilaurate and hydrogen-containing silicone oil;

the alkyl silicon is represented by the formula (1):

the compound of the formula (1),

wherein R in the formula₁、R₂、R₃、R₄Each independently is C₁～C₁₀Alkyl or aryl of (a);

the viscosity of the silicone rubber is 1000-80000 centipoises.

2. The aqueous printing plate of claim 1 wherein the alkylsilane is according to formula (1):

the compound of the formula (1),

wherein R in the formula₁、R₂、R₃、R₄Is C₁～C₁₀An alkyl group or an aryl group of (a),

R₂、R₃、R₄the same is true.

3. The aqueous printing plate according to claim 1 wherein the organic solvent is selected from at least one of alcohols, ketones, ethers, esters, and hydrocarbons;

the ketone is at least one of acetone, butanone, cyclohexanone, N-methyl pyrrolidone and N-ethyl pyrrolidone;

the ether is at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol dimethyl ether and propylene glycol diethyl ether;

the ester is at least one of ethyl acetate, methyl acetate, ethyl formate, butyl formate and propylene glycol monomethyl ether acetate;

the hydrocarbon is at least one of n-heptane, n-hexane, toluene and xylene.

4. The aqueous printing plate according to claim 3 wherein the alcohol is selected from C₅The following monohydric, dihydric or trihydric alcohols.

5. The aqueous printing plate of claim 1, wherein the hydrophilic group-containing polymer layer is formed from at least one of polyethylene glycol, polyethylene glycol formal, polyethylene glycol butyral, polyacrylic acid, polymethyl acrylate, polyethyl acrylate, polymethacrylic acid, polybutylmethacrylate, and polyurethane.

6. The aqueous printing plate according to claim 1, wherein the base layer has a thickness of 0.15 to 0.60mm, the primer layer is coated to a thickness of 5 to 100 μm, and the image-text layer is formed to a thickness of 5 to 1000 μm.

7. The aqueous printing plate according to claim 1, wherein the base layer has a thickness of 0.20 to 0.40mm, the primer layer has a coating thickness of 10 to 80 μm, and the image-text layer has a formation thickness of 10 to 800 μm.

8. The aqueous printing plate according to claim 1, wherein the base layer has a thickness of 0.20 to 0.40mm, the primer layer is coated to a thickness of 10 to 50 μm, and the image-text layer is formed to a thickness of 10 to 500 μm.

9. A method for preparing an aqueous printing plate according to any of claims 1 to 8, comprising the steps of:

(1) coating an aqueous printing plate composition on a base layer and carrying out first curing to form a primer layer;

(2) and coating a hydrophilic group-containing polymer on the base coat and carrying out second curing to form a picture-text layer.

10. The method of claim 9, wherein in step (2), the formation of the teletext layer comprises: ink jet printing, and photoimaging.

11. A lithographic system comprising an ink tank, a doctor blade, a plate cylinder, an impression cylinder;

wherein the aqueous printing plate according to any one of claims 1 to 8 is attached to the outer surface of a plate cylinder, and a clamp plate is provided for fixing the aqueous printing plate; a clamping plate groove is arranged on the impression cylinder;

wherein, the water-based printing plate is immersed into an ink tank to adsorb water-based printing ink, and a scraper is used for removing the redundant ink on the water-based printing plate; rotating the plate cylinder to enable the water-based printing plate adsorbing the water-based printing ink to be in contact with the front surface of the printing stock, and simultaneously rotating the impression cylinder to be in contact with the back surface of the printing stock and applying pressure to enable the front surface of the printing stock to be printed with image-text information; the clamp plate falls into the clamp plate groove along with the rotation of the plate cylinder, and then leaves the clamp plate groove along with the rotation of the plate cylinder.

12. Use of the lithographic system of claim 11 in an aqueous printing ink.

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