A gage printed liner and method of making and use in a printing press cylinder

Abstract

The application discloses a printing pad with a scale, a preparation method of the printing pad and application of the printing pad in a printing machine roller, and belongs to the technical field of the printing pad. The printing pad is composed of a base material and a PET film with scale marks printed on the surface. The base material is mainly EVA with a VA content of 25-28%, supplemented with modified guta-percha, ethylene-propylene-diene rubber, modified composite filler, and a small amount of antioxidant and lubricant. The printing pad provided by the application has the functions of high elastic recovery, tear resistance and size visualization, is suitable for covering the printing machine roller, and can significantly improve the plate mounting efficiency and service life.

Description

Technical Field

[0001] This application belongs to the technical field of printing pads, specifically relating to a pad with a scale for printing, its preparation method, and its application in printing press cylinders. Background Technology

[0002] The printing press cylinder liner is a crucial elastic buffer layer between the blanket and the plate cylinder in an offset printing press. Its performance directly affects dot reproduction, printing pressure uniformity, and equipment lifespan. Existing liner materials are mostly fiber-rubber composite boards or pure rubber sheets, and generally suffer from the following defects:

[0003] 1. Hardness is not visible: Traditional pads have no reference scale, and the only way to adjust the pressure during plate mounting is through repeated test pressure and padding paper, which is time-consuming, material-intensive, and has low precision.

[0004] 2. Poor elastic recovery: It is prone to permanent deformation under high-frequency impact and heat accumulation conditions, resulting in printing pressure drift and requiring frequent replacement;

[0005] 3. Insufficient mechanical strength: Ordinary rubber has low tear strength and is easily torn during disassembly or high-speed operation, causing downtime;

[0006] IV. Uneven packing material dispersion: Single inorganic packing material is prone to agglomeration, which leads to local stress concentration in the gasket and accelerates fatigue failure.

[0007] Therefore, developing a new type of pad that combines "visible scale, high elastic recovery, and excellent mechanical strength" has become a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0008] In view of the shortcomings of the prior art, the purpose of this invention is to provide a novel pad that combines a visible scale, high elastic recovery, and excellent mechanical strength.

[0009] To achieve the above objectives, the present invention discloses the following technical solutions:

[0010] In a first aspect, the present invention provides a pad with a ruler printed on it, the pad containing a base material and a PET film, wherein the PET film is printed with ruler markings;

[0011] The matrix material contains the following components by mass parts:

[0012]

[0013]

[0014] Preferably, the antioxidant is at least one of antioxidant 626, antioxidant 1010, and antioxidant 1076;

[0015] Preferably, the lubricant is at least one of fatty acid amide, stearic acid, polyethylene wax, and ethylene bis-stearamide.

[0016] Preferably, the VA content in the EVA is 25-28%.

[0017] Preferably, the preparation method of the modified Eucommia ulmoides gum includes the following steps:

[0018] Step 1-1. Put the eucommia gum into a mixer and mix for 1 minute until it is melted and uniform;

[0019] Step 1-2. Add maleic anhydride and antioxidant 1010 to the internal mixer and mix for 2 minutes;

[0020] Steps 1-3. After heating dicumyl peroxide into a liquid, slowly inject it into the mixing chamber and mix for 3 minutes. Then raise the temperature to 175±5℃, reduce the rotor speed to 40r / min, and continue the reaction for 5-8 minutes. After the reaction is completed, discharge the material to obtain modified Eucommia ulmoides gum.

[0021] More preferably, the temperature of the internal mixer in step 1-1 is 160-170℃, and the rotor speed is 60-70 r / min.

[0022] More preferably, the mass ratio of the eucommia gum, maleic anhydride, antioxidant 1010 and dicumyl peroxide is 100:(1.5-3.0):(0.2-0.5):(0.3-0.8).

[0023] Preferably, the method for preparing the modified filler includes the following steps:

[0024] Step 2-1. Mix KH-550 with anhydrous ethanol at a volume ratio of 1:(9-11)v / v, stir at 200r / min for 10min, then add deionized water at a mass of 7-9% of KH-550, hydrolyze for 30min to obtain hydrolyzed KH-550.

[0025] Step 2-2. Disperse silica particles in anhydrous ethanol at a solid-liquid mass-to-volume ratio of 1:(10-15) g / mL, sonicate for 30 min, then heat to 55-60℃, slowly add hydrolyzed KH-550 under a nitrogen atmosphere, the amount of KH-550 added is 5-8% of the mass of silica particles, stir at 100 r / min for 4 h, centrifuge the resulting solid-liquid mixture, discard the liquid and collect the solid, wash the solid three times with anhydrous ethanol by centrifugation, and dry to obtain modified silica;

[0026] Steps 2-3. Place the aluminum nitride ceramic balls in a high-speed mixer and spray in a KH-550 / toluene solution with a concentration of 20 v / v%. The amount added is 4-5% of the mass of the aluminum nitride ceramic balls. Mix at 3000 r / min for 15 min to obtain modified aluminum nitride ceramic balls.

[0027] Steps 2-4. Mix modified silica and modified aluminum nitride ceramic balls at a mass ratio of (6-7):1, and add 80 v / v% ethanol aqueous solution. Sonicate for 30 min, then heat to 55-60℃ and stir at 200 r / min for 2 h. Finally, centrifuge to collect the solid and dry to obtain the modified filler.

[0028] Preferably, the silica particles have a particle size of 1-3 μm;

[0029] The aluminum nitride ceramic balls have a particle size of 5 μm.

[0030] Preferably, in steps 2-4, the mass-to-volume ratio of modified silica and modified aluminum nitride ceramic balls to the ethanol aqueous solution is 1:10 g / mL.

[0031] In a second aspect, the present invention provides a method for preparing the pad with scale printing as described in the first aspect, the method comprising the following steps:

[0032] Step 3-1. EVA and EPDM rubber are put into a mixer and melted at 120℃ and 50r / min for 2 minutes. The temperature is raised to 170℃ and modified eucommia rubber is added and mixed for 6 minutes. Modified filler, antioxidant and lubricant are added in sequence at 170℃ and 200r / min and mixed for 30 minutes. After cooling to 110℃, the material is discharged to obtain the matrix material.

[0033] Step 3-2. The substrate material is stretched into a film, and then a layer of PET film is attached. The film is pressed at 160°C and 10-20MPa to form a sheet. After printing the scale and size on the PET film, it is cut into individual sheets to obtain the pad with the scale printing.

[0034] Thirdly, the present invention provides the application of the scale-printed pad described in the first aspect in a printing press cylinder.

[0035] The beneficial effects of this invention are:

[0036] 1. The pad provided by the present invention has a layer of PET film attached to its surface, and a scale is printed on its surface. The plate-mounting personnel can intuitively read the thickness and pressure compensation value, changing the traditional experience-based "test pad" to a precise "reading", thus shortening the plate-mounting time.

[0037] 2. The anhydride groups of the modified Eucommia ulmoides gum form chemical bonds with the ester groups of EVA, and with the help of the EPDM crosslinking network, in conjunction with the SiO2 / AlN rigid skeleton, the molecular chain slippage is significantly inhibited, the mechanical properties of the liner are significantly improved, the compression set rate is reduced, and the service life is increased.

[0038] 3. This invention adopts a one-step mixing-film stretching-hot pressing process, which eliminates the need for adhesive coating and lamination, resulting in low energy consumption, high thickness accuracy of the finished product, and a simple process suitable for large-scale production. Detailed Implementation

[0039] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments and comparative examples. The purpose of this description is to provide a detailed understanding of the invention, not to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention.

[0040] Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this invention are all commonly used ordinary reagents and instruments.

[0041] In this invention:

[0042] Silica particles: Micron-sized silica microspheres with an average particle size of 3μm, purchased from Yumu (Ningbo) New Materials Co., Ltd.

[0043] Aluminum nitride ceramic balls: Micron-sized aluminum nitride ceramic balls with an average particle size of 5μm, purchased from Yumu (Ningbo) New Materials Co., Ltd.

[0044] Antioxidant 1010: Purchased from Jiangsu Jiyi New Materials Co., Ltd.;

[0045] All other raw materials are commercially available.

[0046] Example

[0047] Preparation of modified Eucommia ulmoides gum

[0048] Step 1-1. Preheat the internal mixer to 170℃, adjust the rotor speed to 70r / min, add the eucommia gum into the internal mixer, and mix for 1 minute until it melts evenly;

[0049] Step 1-2. Slowly add maleic anhydride and antioxidant 1010 to the internal mixer and mix for 2 minutes;

[0050] Steps 1-3. After heating dicumyl peroxide into a liquid, slowly inject it into the mixing chamber and mix for 3 minutes. Then raise the temperature to 175°C, reduce the rotor speed to 40 r / min, and continue the reaction for 8 minutes. After the reaction is completed, discharge the material to obtain modified Eucommia ulmoides gum.

[0051] The mass ratio of Eucommia ulmoides gum, maleic anhydride, antioxidant 1010 and dicumyl peroxide is 100:2:0.3:0.5, and the mass ratio among them can be selected from 100:(1.5-3.0):(0.2-0.5):(0.3-0.8).

[0052] Preparation of modified fillers

[0053] Step 2-1. Mix KH-550 with anhydrous ethanol at a volume ratio of 1:10 v / v, stir at 200 r / min for 10 min, then add deionized water at 8% of the mass of KH-550, and hydrolyze for 30 min to obtain hydrolyzed KH-550.

[0054] Step 2-2. Disperse silica particles in anhydrous ethanol at a solid-liquid mass-to-volume ratio of 1:15 g / mL, sonicate for 30 min, then heat to 60 °C, slowly add hydrolyzed KH-550 under a nitrogen atmosphere, the amount of KH-550 added is 8% of the mass of silica particles, stir at 100 r / min for 4 h, centrifuge the resulting solid-liquid mixture, discard the liquid and collect the solid, wash the solid three times with anhydrous ethanol by centrifugation, and dry to obtain modified silica;

[0055] Steps 2-3. Place the aluminum nitride ceramic balls in a high-speed mixer and spray in a KH-550 / toluene solution with a concentration of 20 v / v%. The amount added is 5% of the mass of the aluminum nitride ceramic balls. Mix at 3000 r / min for 15 min to obtain modified aluminum nitride ceramic balls.

[0056] Steps 2-4. Modified silica and modified aluminum nitride ceramic balls are mixed at a mass ratio of 6:1, and an 80 v / v% ethanol aqueous solution is added simultaneously. The mass-volume ratio of the mixture to the ethanol aqueous solution is 1:10 g / mL. The mixture is ultrasonically treated for 30 min to trigger the interfacial condensation reaction. Then, it is heated to 60℃ and stirred at 200 r / min for 2 h to enhance crosslinking. Finally, the solid is collected by centrifugation and dried to obtain the modified SiO2 / AlN filler.

[0057] Preparation of pads with printed scales

[0058] Step 3-1. By weight, take 60-70 parts of EVA with a VA content of 25-28%, 25-30 parts of modified Eucommia ulmoides rubber, 10-15 parts of EPDM rubber, 8-10 parts of modified filler, 0.3-0.5 parts of antioxidant 1010, and 0.5-0.7 parts of lubricant, according to the specific weight proportions in Table 1.

[0059] Step 3-2. EVA and EPDM rubber are put into a mixer and melted at 120℃ and 50r / min for 2 minutes. The temperature is raised to 170℃ and modified eucommia rubber is added and mixed for 6 minutes. Modified filler, antioxidant and lubricant are added in sequence at 170℃ and 200r / min and mixed for 30 minutes. After cooling to 110℃, the composite material is discharged, which is the base material of the gasket.

[0060] Step 3-3. The composite material is stretched into a film, then a layer of PET film is attached, and the film is pressed at 160°C and 15MPa. After printing the scale and size on the PET film, it is cut into individual sheets to obtain the pad with the scale printing.

[0061] Table 1. Raw material mass fractions

[0062]

[0063]

[0064] Note: " / " in the table indicates no addition.

[0065] Comparative Example

[0066] Preparation of Comparative Example 1

[0067] The preparation method of Comparative Example 1 is the same as that of Example 2, except that modified Eucommia ulmoides gum is not used and the missing amount is made up with EVA. Otherwise, it is the same as Example 2.

[0068] Preparation of Comparative Example 2

[0069] The preparation method of Comparative Example 2 is the same as that of Example 2, except that EPDM rubber is missing and the missing amount is made up with EVA. Otherwise, it is the same as Example 2.

[0070] Preparation of Comparative Example 3

[0071] The preparation method of Comparative Example 3 is the same as that of Example 2, except that the modified filler is missing and the missing amount is made up with EVA. Otherwise, it is the same as Example 2.

[0072] Preparation of Comparative Example 4

[0073] The preparation method of Comparative Example 4 is the same as that of Example 2, except that the modified filler is replaced with modified silica.

[0074] The preparation method of the modified silica refers to steps 2-1 and 2-2 in the preparation method of modified filler.

[0075] Preparation of Comparative Example 5

[0076] The preparation method of Comparative Example 5 is the same as that of Example 2, except that the modified filler is replaced with modified aluminum nitride ceramic balls.

[0077] The preparation method of the modified aluminum nitride ceramic balls refers to steps 2-3 in the preparation method of modified fillers.

[0078] Performance testing

[0079] The following performance tests were performed on the liner matrix materials prepared in Examples 1-3 and Comparative Examples 1-5. The specific test data are shown in Table 2:

[0080] Hardness test: The hardness test was conducted in accordance with GB / T 531.1-2008 "Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore hardness test (Shore hardness)" using a Shore hardness tester of type A.

[0081] Tear strength: The tear strength test was conducted in accordance with GB / T 529-2008 "Determination of tear strength of vulcanized rubber or thermoplastic rubber (trouser-shaped, right-angled and crescent-shaped specimens)". The tensile speed was 500 mm / min, the test temperature was 25±2℃, and the specimen was a right-angled specimen.

[0082] Tensile strength: The tensile strength test was conducted in accordance with GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". The tensile speed was 500 mm / min, the test temperature was 25±2℃, and the specimen was a type 2 dumbbell-shaped specimen.

[0083] Compression set test: The compression set test was conducted in accordance with GB / T 7795.1-2015 "Determination of compression set of vulcanized rubber or thermoplastic rubber" to evaluate the elastic recovery ability after long-term compression.

[0084] Table 2 Performance Test Results

[0085]

[0086] Results analysis:

[0087] According to the test results, the hardness of the padding matrix material in Examples 1-3 is between 55 and 60, which is moderate and meets the hardness requirements of the padding. Its tear strength reaches 30 kN·m. -1 The tensile strength reaches over 15MPa, the compression set is controlled within 25%, and it has excellent mechanical properties and elastic recovery rate, thus improving the service life of the gasket.

[0088] This invention achieves performance optimization through a triple collaborative mechanism:

[0089] First, in Examples 1-3, the anhydride groups of the modified Eucommia ulmoides gum form chemical bonds with the ester groups of the EVA molecular chain, which significantly strengthens the interfacial bonding force and enhances the mechanical properties of the matrix material. At the same time, a certain amount of EPDM rubber is introduced. EPDM rubber has good compatibility with EVA, which improves its elasticity and weather resistance, further improving the wear resistance and resilience of EVA, enhancing the elastic recovery rate of the material, and increasing the service life of the gasket.

[0090] Secondly, in Examples 1-3, when SiO2 / AlN composite fillers were used, aluminum nitride ceramic spheres, acting as a rigid framework embedded in the silica agglomerates, effectively suppressed the structural collapse of silica under high shear, allowing the filler network to maintain stable support under compressive stress. Furthermore, the rigid segments of eucommia gum (trans-1,4-polyisoprene) synergistically inhibited molecular chain slippage with the SiO2 / AlN composite filler network, further reducing the compression set and improving the elastic recovery rate. It is worth noting that the aluminum nitride content needs to be controlled at 1 / 6 of the silica content. Aluminum nitride, as a rigid particulate material... Excessive use of aluminum nitride will hinder molecular chain movement and increase the brittleness of the material, while insufficient content will fail to support the silicon dioxide structure. In the preliminary experiments of this application, we tried to reduce the aluminum nitride ratio to 1:10, which resulted in filler agglomeration. Therefore, controlling the ratio of the two to 1:6-1:7 can bring better results. The solution of this application makes the tear strength of Examples 1-3 reach more than 30MPa, while controlling the compression set rate to within 25%, which proves that the pad matrix provided by Examples 1-3 can provide excellent elastic recovery and elastic resistance to printing pads and improve the service life of the pads.

[0091] Compared with Comparative Example 4, which uses only silica, its tear strength is 26.2 MPa and its deformation rate is 28.9%. Compared with Comparative Example 5, which uses only aluminum nitride, its tear strength is 24.0 MPa and its deformation rate is 32.1%. The SiO2 / AlN composite filler improved the tear resistance by more than 19% and significantly enhanced the compression recovery ability, verifying the rigidity auxiliary value of aluminum nitride and silica.

[0092] In Comparative Example 1, the absence of modified Eucommia ulmoides gum led to a surge in the compression set rate to 36.8%, confirming that the compatibilization effect of the anhydride groups and EVA ester groups is crucial for maintaining elasticity. In Comparative Example 2, the absence of EPDM rubber resulted in a decrease in chain slip resistance and an increase in the compression set rate to 33.5%, demonstrating the stabilizing effect of the EPDM crosslinking network under long-term pressure. Comparative Example 3, with the absence of filler, exhibited a compression set rate as high as 41.2%, proving that Si... O2 / AlN filler networks are indispensable for confining permanent displacement of molecular chains.

[0093] In summary, the embodiments 1-3 provided by the present invention demonstrate the optimal balance of this formulation in the application of printing pads by exhibiting moderate hardness, excellent tear strength, and excellent compression set. This balance provides rigid support to resist the impact of printing pressure while relying on the elastomer network to achieve a good service life under harsh operating conditions.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A pad with a printed ruler, characterized in that, The padding contains a base material and a PET film, on which scale markings are printed. The matrix material contains the following components by mass parts: 60-70 portions of EVA; 25-30 parts of modified Eucommia ulmoides gum; 10-15 parts of EPDM rubber; 8-10 parts of modified filler; Antioxidant 0.3-0.5 parts; Lubricant 0.5-0.7 parts; The antioxidant is at least one of antioxidant 626, antioxidant 1010, and antioxidant 1076; The lubricant is at least one of fatty acid amide, stearic acid, polyethylene wax, and ethylene bis-stearamide; The VA content in the EVA is 25-28%; The preparation method of the modified Eucommia ulmoides gum includes the following steps: Step 1-1. Add the eucommia gum into the internal mixer and mix for 1 minute until it is uniformly melted; Step 1-2. Add maleic anhydride and antioxidant 1010 to the internal mixer and mix for 2 minutes; Steps 1-3. After heating dicumyl peroxide into a liquid, slowly inject it into the mixing chamber and mix for 3 minutes. Then raise the temperature to 175±5℃, reduce the rotor speed to 40r / min, and continue the reaction for 5-8 minutes. After the reaction is completed, discharge the material to obtain modified Eucommia ulmoides gum. The mass ratio of Eucommia ulmoides gum, maleic anhydride, antioxidant 1010, and dicumyl peroxide is 100:(1.5-3.0):(0.2-0.5):(0.3-0.8). The method for preparing the modified filler includes the following steps: Step 2-1. Mix KH-550 with anhydrous ethanol at a volume ratio of 1:(9-11)v / v, stir at 200r / min for 10min, then add deionized water at a mass of 7-9% of KH-550, hydrolyze for 30min to obtain hydrolyzed KH-550. Step 2-2. Disperse silica particles in anhydrous ethanol at a solid-liquid mass-to-volume ratio of 1:(10-15) g / mL, sonicate for 30 min, then heat to 55-60℃, slowly add hydrolyzed KH-550 under a nitrogen atmosphere, the amount of KH-550 added is 5-8% of the mass of silica particles, stir at 100 r / min for 4 h, centrifuge the resulting solid-liquid mixture, discard the liquid and collect the solid, wash the solid three times with anhydrous ethanol by centrifugation, and dry to obtain modified silica; Steps 2-3. Place the aluminum nitride ceramic balls in a high-speed mixer and spray in a KH-550 / toluene solution with a concentration of 20v / v%, adding 4-5% of the mass of the aluminum nitride ceramic balls. Mix at 3000r / min for 15min to obtain modified aluminum nitride ceramic balls. Steps 2-4. Mix modified silica and modified aluminum nitride ceramic balls at a mass ratio of (6-7):1, and add 80 v / v% ethanol aqueous solution. Sonicate for 30 min, then heat to 55-60℃ and stir at 200 r / min for 2 h. Finally, centrifuge to collect the solid and dry to obtain the modified filler.

2. The pad with printed scale according to claim 1, characterized in that, In step 1-1, the temperature of the internal mixer is 160-170℃ and the rotor speed is 60-70 r / min.

3. The pad with printed scale according to claim 1, characterized in that, The silica particles have a particle size of 1-3 μm; The aluminum nitride ceramic balls have a particle size of 5 μm.

4. The pad with printed scale according to claim 1, characterized in that, In steps 2-4, the mass-to-volume ratio of modified silica and modified aluminum nitride ceramic balls to ethanol aqueous solution is 1:10 g / mL.

5. The method for preparing the pad with printed scale according to any one of claims 1-4, characterized in that, The preparation method includes the following steps: Step 3-1. EVA and EPDM rubber are put into a mixer and melted at 120℃ and 50r / min for 2 minutes. The temperature is raised to 170℃ and modified eucommia rubber is added and mixed for 6 minutes. Modified filler, antioxidant and lubricant are added in sequence at 170℃ and 200r / min and mixed for 30 minutes. After cooling to 110℃, the material is discharged to obtain the matrix material. Step 3-2. The substrate material is stretched into a film, and then a layer of PET film is attached. The film is pressed at 160°C and 10-20MPa to form a sheet. After printing the scale and size on the PET film, it is cut into individual sheets to obtain the pad with the scale printing.

6. The application of the scale-printed pad according to any one of claims 1-4 in a printing press cylinder.

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