Application method of chromium nitride coating on surface of silicone rubber mold

Abstract

The invention provides an application method of a chromium nitride coating on the surface of a silicon rubber mold, which comprises the step of spraying the chromium nitride coating with the thickness of 0.3-0.5 mu m on the surface of the silicon rubber mold by adopting a magnetron sputtering method to improve the demolding property of the silicon rubber mold. The application method disclosed by the invention is simple to operate, the chromium nitride coating is sprayed on the surface of the silicon rubber mold, so that the silicon rubber mold can be ensured to have very good demolding property, the wear resistance and hardness of the silicon rubber mold can be improved, the service life of the mold is prolonged, and the application method has a wide-range popularization and application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of mold processing, and in particular to an application method of a chromium nitride coating on the surface of a silicone rubber mold. Background Art

[0002] At present, the surface of silicone rubber molds made of mold steel is sprayed with Teflon coating to improve the mold surface demoulding properties. Teflon coating is a high molecular polymer made by polymerization of tetrafluoroethylene as a monomer. This material has the characteristics of acid and alkali resistance and resistance to various organic solvents, and is almost insoluble in all solvents. At the same time, polytetrafluoroethylene has the characteristics of high temperature resistance, its friction coefficient is extremely low, and it hardly adheres to any substance, so it has become an ideal coating for many molds.

[0003] However, Teflon itself is not very wear-resistant. In long-term use, the Teflon coating is easily worn and cracked or peeled off, and has been adsorbed on the surface of silicone rubber products, which reduces the product yield. In addition, since more chemicals and high-temperature production processes are required when manufacturing Teflon coatings, this will cause environmental pollution and energy waste. Moreover, once the Teflon coating is burned, it will release toxic gases, which are harmful to human health and the environment.

[0004] CN109943871A discloses a surface coating of a die-casting mold and a preparation method thereof. The coating is a composite coating, which includes a transition bonding layer, an electroplating layer and a ceramic protective layer in order from a mold steel substrate to the outside; the mold steel substrate is electroplated to form an electroplating layer; the electroplating layer is subjected to arc impact to cause the electroplating layer and elements of the mold steel substrate to diffuse with each other, metallurgically bond, and form a transition bonding layer; the ceramic protective layer is formed by in-situ oxidation of metal elements on the outer surface of the electroplating layer during the die-casting process.

[0005] CN115874238A discloses a method for plating a molding mold. An aqueous solution containing a compound of a plating metal, conductive salts, a buffer, a pH regulator and additives is injected into a plating tank and stirred to form a plating solution. The workpiece to be plated is used as a cathode and the plating metal made into an anode is immersed in the plating solution inside the plating tank. The workpiece to be plated and the plating metal are connected to the negative electrode and the positive electrode of a direct current power supply respectively, so that the metal ions in the plating solution move to the cathode to form a plating layer under the action of the potential difference, and titanium chromium aluminum nitride is electroplated on the surface of the mold to form a nano-level coating.

[0006] CN103397295A discloses a TiN double-layer coating on the surface of a tool and mold material and a preparation method thereof, comprising the following steps: (1) mechanically grinding and then cleaning the ion-plated TiN layer on the surface of the tool and mold material; and (2) plating the TiN layer using a magnetic filtration ion plating device to obtain the TiN double-layer coating.

[0007] However, the above-mentioned mold coating methods are complicated to operate, and these coatings cannot effectively improve the demoulding properties of the silicone rubber mold. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides a method for applying a chromium nitride coating on the surface of a silicone rubber mold. The chromium nitride coating is sprayed on the surface of the silicone rubber mold by a magnetron sputtering method, which can greatly improve the demolding performance of the silicone rubber mold, while improving the wear resistance and hardness of the mold and extending the service life of the mold.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] The present invention provides a method for applying a chromium nitride coating on the surface of a silicone rubber mold, the method comprising:

[0011] A chromium nitride coating with a thickness of 0.3 to 0.5 μm is sprayed on the surface of a silicone rubber mold by a magnetron sputtering method to improve the demoulding property of the silicone rubber mold.

[0012] The method for applying the chromium nitride coating on the surface of a silicone rubber mold described in the present invention sprays a chromium nitride coating with a thickness of 0.3 to 0.5 μm on the surface of the mold, thereby greatly improving the demoulding property, wear resistance and hardness of the mold surface, making it easy for the mold to peel off the silicone rubber product. Moreover, no chromium ions are generated during the preparation of the chromium nitride coating, and there is no pollution to the environment throughout the process. When the thickness of the chromium nitride coating is thin, the surface finish of the mold is poor, the wear resistance is poor, and it cannot play a protective role; when the thickness of the chromium nitride coating is thick, the wear resistance and hardness of the mold surface are significantly improved, and at the same time, the friction between the mold and the product is increased, which is not conducive to demoulding; the appropriate coating thickness can not only ensure low friction, but also provide higher wear resistance and hardness.

[0013] The invention solves the problem that the demoulding property of the silicone mold is poor during the production process, the product is easily adsorbed on the upper film surface of the mold, so that the product cannot be completely removed, resulting in the product being unable to be smoothly produced or the complete product yield being low.

[0014] The thickness of the chromium nitride coating of the present invention is 0.3-0.5 μm, for example, 0.3 μm, 0.35 μm, 0.4 μm, 0.43 μm, 0.45 μm or 0.5 μm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] Preferably, the material of the silicone rubber mold includes any one of P20 mold steel, S50C mold steel, 718H mold steel or S136 mold steel.

[0016] Preferably, the purity of the sputtering gas argon in the magnetron sputtering is ≥99.99%, for example, it can be 99.991%, 99.992%, 99.993%, 99.995%, 99.997% or 99.998%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, the flow rate of the argon gas is 20 to 80 mL / min, for example, it can be 20 mL / min, 30 mL / min, 40 mL / min, 50 mL / min, 60 mL / min or 80 mL / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] Preferably, the working pressure of the argon gas is 0.2-0.8 MPa, for example, it can be 0.2 MPa, 0.3 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa or 0.8 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] Preferably, the purity of the reactive gas nitrogen in the magnetron sputtering is ≥99.999%, for example, it can be 99.9991%, 99.9992%, 99.9994%, 99.9995%, 99.9997% or 99.9998%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] Preferably, the nitrogen flow rate is 20 to 80 mL / min, for example, 20 mL / min, 30 mL / min, 40 mL / min, 50 mL / min, 60 mL / min or 80 mL / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] The preferred nitrogen flow rate of the present invention is 20-80 mL / min, which ensures that a chromium nitride coating is formed on the surface of the silicone rubber mold, greatly improving the wear resistance and hardness of the silicone rubber mold. Because as the nitrogen flow rate increases, the sputtering voltage will increase, which will cause the thin film formed by magnetron sputtering on the surface of the silicone rubber mold to change. When the nitrogen flow rate is low, the deposited film layer is mainly Cr and Cr2N; when the nitrogen flow rate gradually increases; when the Cr content increases, the film layer structure is Cr2N and CrN; when the nitrogen flow rate is high, the film deposition layer is mainly CrN.

[0022] Preferably, the working pressure of the nitrogen is 0.2-0.8 MPa, for example, 0.2 MPa, 0.3 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa or 0.8 MPa, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the vacuum degree of the deposition chamber in the magnetron sputtering is 2×10 -3 ~7×10 -3 MPa, for example, it can be 2×10 -3 MPa, 2.5×10 -3 MPa, 3×10 -3 MPa, 5×10 -3 MPa, 6×10 -3 MPa or 7×10 -3 MPa, etc., but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the purity of the chromium target in the magnetron sputtering is ≥99.5%, for example, it can be 99.5%, 99.53%, 99.55%, 99.6%, 99.7% or 99.8%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] Preferably, the temperature of the silicone rubber mold in the magnetron sputtering is 200-350°C, for example, it can be 200°C, 210°C, 250°C, 270°C, 300°C, 320°C or 350°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0026] Preferably, the distance between the chromium target and the silicone rubber mold is 20 to 100 mm, for example, 20 mm, 30 mm, 50 mm, 70 mm, 90 mm or 100 mm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the target voltage in the magnetron sputtering is 300-600V, for example, 300V, 350V, 400V, 450V, 500V, 550V or 600V, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0028] The present invention preferably uses a target voltage of 300 to 600 V in the magnetron sputtering to control the deposition rate of the chromium nitride coating and ensure that the final thickness is 0.3 to 0.5 μm. The higher the target voltage, the faster the target material atom sputtering rate and the faster the chromium nitride coating deposition rate. When the target voltage is small, the chromium nitride coating will be thinner, and the hardness and wear resistance of the silicone rubber mold will still be poor; when the target voltage is large, the chromium nitride coating will be thicker and will fall off.

[0029] Target current density is 10~50mA / cm 2 , for example, it can be 10mA / cm 2 , 15mA / cm 2 , 20mA / cm 2 , 25mA / cm 2 、30mA / cm 2 or 50mA / cm 2 The above range is not limited to the listed values, and other values ​​not listed within the above range are also applicable.

[0030] Preferably, before spraying the chromium nitride coating, the silicone rubber mold is sequentially cleaned, polished and sandblasted.

[0031] Preferably, the cleaning process comprises an ultrasonic cleaning process;

[0032] Preferably, the frequency of the ultrasonic wave in the ultrasonic cleaning process is 20 to 30 KHz, for example, it can be 20 KHz, 22 KHz, 25 KHz, 27 KHz, 29 KHz or 30 KHz, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, the cleaning liquid used in the cleaning process includes a water-based cleaning agent, specifically an ultrasonic cleaning agent JX-401B.

[0034] Preferably, the temperature of the cleaning treatment is 40-70°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C or 70°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0035] Preferably, the cleaning treatment time is 25 to 50 minutes, for example, it can be 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes or 50 minutes, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the polishing liquid used in the polishing treatment is a water-soluble polishing liquid, which has good degreasing, rust-proofing, cleaning and gloss-enhancing properties, can make the metal product show a true metallic luster, and has stable performance, is non-toxic, and does not pollute the environment.

[0037] Preferably, the grit used in the sandblasting process includes brown corundum with a particle size of 80 to 120 meshes, for example, it can be 80 mesh, 90 mesh, 100 mesh, 110 mesh, 115 mesh or 120 mesh, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] Preferably, the distance between the silicone rubber mold and the sandblasting nozzle during the sandblasting process is 100 to 200 mm, for example, 100 mm, 110 mm, 120 mm, 150 mm, 170 mm or 200 mm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the pressure of the sandblasting treatment is 0.2-0.8 MPa, for example, it can be 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.7 MPa or 0.8 MPa, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the flow rate of the sandblasting treatment is 5 to 15 L / min, for example, it can be 5 L / min, 7 L / min, 8 L / min, 10 L / min, 13 L / min or 15 L / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] Preferably, the angle of the nozzle in the sandblasting process is 60-75°, for example, it can be 60°, 62°, 65°, 67°, 70° or 75°, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] As a preferred technical solution of the present invention, the application method comprises:

[0043] After the silicone rubber mold is cleaned, polished and sandblasted in sequence, a chromium nitride coating with a thickness of 0.3 to 0.5 μm is sprayed on the surface of the silicone rubber mold by a magnetron sputtering method to improve the demoulding property of the silicone rubber mold;

[0044] The cleaning process includes ultrasonic cleaning process; the frequency of the ultrasonic wave in the ultrasonic cleaning process is 20 to 30 KHz; the cleaning liquid used in the cleaning process includes a water-based cleaning agent; the temperature of the cleaning process is 40 to 70° C., and the time is 25 to 50 minutes; the polishing liquid used in the polishing process is a water-soluble polishing liquid;

[0045] The grit used in the sandblasting process includes brown corundum with a particle size of 80 to 120 meshes; the distance between the silicone rubber mold and the sandblasting nozzle in the sandblasting process is 100 to 200 mm; the pressure of the sandblasting process is 0.2 to 0.8 MPa, the flow rate is 5 to 15 L / min, and the angle of the nozzle in the sandblasting process is 60 to 75°;

[0046] The material of the silicone rubber mold includes any one of P20 mold steel, S50C mold steel, 718H mold steel or S136 mold steel;

[0047] The purity of the sputtering gas argon in the magnetron sputtering is ≥99.99%; the flow rate of the argon is 20-80 mL / min; the working pressure of the argon is 0.2-0.8 MPa;

[0048] The purity of the reactive gas nitrogen in the magnetron sputtering is ≥99.999%; the nitrogen flow rate is 20-80 mL / min; the working pressure of the nitrogen is 0.2-0.8 MPa;

[0049] The vacuum degree of the deposition chamber in the magnetron sputtering is 2×10 -3 ~7×10 -3 MPa; the purity of the chromium target in the magnetron sputtering is ≥99.5%; the temperature of the silicone rubber mold in the magnetron sputtering is 200-350°C; the distance between the chromium target and the silicone rubber mold is 20-100mm;

[0050] The target voltage in the magnetron sputtering is 300-600V; the target current density is 10-50mA / cm 2 .

[0051] Compared with the prior art, the present invention has at least the following beneficial effects:

[0052] The method for applying the chromium nitride coating on the surface of a silicone rubber mold provided by the present invention is simple to operate and has a low application cost. By spraying the chromium nitride coating on the surface of the silicone rubber mold, it can be ensured that the silicone rubber mold has good demoulding properties and can improve the wear resistance and hardness of the silicone rubber mold, so that the mold is not easily scratched during cleaning, thereby extending the service life of the mold to a certain extent. In addition, the chromium nitride coating will not cause pollution to the environment during the spraying process, and is an ideal silicone rubber mold coating. DETAILED DESCRIPTION

[0053] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0054] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0055] The following are typical but non-limiting embodiments of the present invention:

[0056] Example 1

[0057] This embodiment provides a method for applying a chromium nitride coating on the surface of a silicone rubber mold, the method comprising:

[0058] After the silicone rubber mold is subjected to sandblasting, polishing and cleaning in sequence, a chromium nitride coating with a thickness of 0.5 μm is sprayed on the surface of the silicone rubber mold by a magnetron sputtering method to improve the demoulding property of the silicone rubber mold;

[0059] The grit used in the sandblasting process includes brown corundum with a particle size of 100 mesh; the distance between the silicone rubber mold and the sandblasting nozzle in the sandblasting process is 130 mm; the pressure of the sandblasting process is 0.5 MPa, and the flow rate is 8 L / min; the angle of the nozzle in the sandblasting process is 68°;

[0060] The polishing liquid used in the polishing process is a water-soluble polishing liquid; the cleaning process includes an ultrasonic cleaning process; the frequency of the ultrasonic wave in the ultrasonic cleaning process is 23KHz; the cleaning liquid used in the cleaning process includes a water-based cleaning agent; the temperature of the cleaning process is 60°C and the time is 40 minutes;

[0061] The silicone rubber mold is made of P20 mold steel;

[0062] The purity of the sputtering gas argon in the magnetron sputtering is 99.99%; the flow rate of the argon is 60 mL / min; the working pressure of the argon is 0.5 MPa;

[0063] The purity of the reactive gas nitrogen in the magnetron sputtering is 99.999%; the nitrogen flow rate is 50 mL / min; the working pressure of the nitrogen is 0.3 MPa;

[0064] The vacuum degree of the deposition chamber in the magnetron sputtering is 3×10 -3 MPa; the purity of the chromium target in the magnetron sputtering is 99.5%; the temperature of the silicone rubber mold in the magnetron sputtering is 250°C; the distance between the chromium target and the silicone rubber mold is 60mm;

[0065] The target voltage in the magnetron sputtering is 400 V; the target current density is 30 mA / cm 2 .

[0066] Example 2

[0067] This embodiment provides a method for applying a chromium nitride coating on the surface of a silicone rubber mold, the method comprising:

[0068] After the silicone rubber mold is subjected to sandblasting, polishing and cleaning in sequence, a chromium nitride coating with a thickness of 0.3 μm is sprayed on the surface of the silicone rubber mold by a magnetron sputtering method to improve the demoulding property of the silicone rubber mold;

[0069] The grit used in the sandblasting process includes brown corundum with a particle size of 80 mesh; the distance between the silicone rubber mold and the sandblasting nozzle in the sandblasting process is 200 mm; the pressure of the sandblasting process is 0.8 MPa, and the flow rate is 5 L / min; the angle of the nozzle in the sandblasting process is 75°;

[0070] The polishing liquid used in the polishing process is a water-soluble polishing liquid; the cleaning process includes an ultrasonic cleaning process; the frequency of the ultrasonic wave in the ultrasonic cleaning process is 20KHz; the cleaning liquid used in the cleaning process includes a water-based cleaning agent; the temperature of the cleaning process is 70°C and the time is 50 minutes;

[0071] The silicone rubber mold is made of S50C mold steel;

[0072] The purity of the sputtering gas argon in the magnetron sputtering is 99.993%; the flow rate of the argon is 80 mL / min; the working pressure of the argon is 0.2 MPa;

[0073] The purity of the reactive gas nitrogen in the magnetron sputtering is 99.9992%; the nitrogen flow rate is 20 mL / min; the working pressure of the nitrogen is 0.2 MPa;

[0074] The vacuum degree of the deposition chamber in the magnetron sputtering is 7×10 -3 MPa; the purity of the chromium target in the magnetron sputtering is 99.53%; the temperature of the silicone rubber mold in the magnetron sputtering is 350°C; the distance between the chromium target and the silicone rubber mold is 20mm;

[0075] The target voltage in the magnetron sputtering is 600 V; the target current density is 10 mA / cm 2 .

[0076] Example 3

[0077] This embodiment provides a method for applying a chromium nitride coating on the surface of a silicone rubber mold, the method comprising:

[0078] After the silicone rubber mold is subjected to sandblasting, polishing and cleaning in sequence, a chromium nitride coating with a thickness of 0.4 μm is sprayed on the surface of the silicone rubber mold by a magnetron sputtering method to improve the demoulding property of the silicone rubber mold;

[0079] The grit used in the sandblasting process includes brown corundum with a particle size of 120 mesh; the distance between the silicone rubber mold and the sandblasting nozzle in the sandblasting process is 100 mm; the pressure of the sandblasting process is 0.2 MPa, and the flow rate is 15 L / min; the angle of the nozzle in the sandblasting process is 60°;

[0080] The polishing liquid used in the polishing process is a water-soluble polishing liquid; the cleaning process includes an ultrasonic cleaning process; the frequency of the ultrasonic wave in the ultrasonic cleaning process is 30KHz; the cleaning liquid used in the cleaning process includes a water-based cleaning agent; the temperature of the cleaning process is 40°C and the time is 25 minutes;

[0081] The silicone rubber mold is made of S136 mold steel;

[0082] The purity of the sputtering gas argon in the magnetron sputtering is 99.996%; the flow rate of the argon is 20 mL / min; the working pressure of the argon is 0.8 MPa;

[0083] The purity of the reactive gas nitrogen in the magnetron sputtering is 99.9995%; the nitrogen flow rate is 80 mL / min; the working pressure of the nitrogen is 0.8 MPa;

[0084] The vacuum degree of the deposition chamber in the magnetron sputtering is 2×10 -3 MPa; the purity of the chromium target in the magnetron sputtering is 99.58%; the temperature of the silicone rubber mold in the magnetron sputtering is 200°C; the distance between the chromium target and the silicone rubber mold is 100mm;

[0085] The target voltage in the magnetron sputtering is 300 V; the target current density is 50 mA / cm 2 .

[0086] Example 4

[0087] This embodiment provides a method for applying a chromium nitride coating on the surface of a silicone rubber mold. The application method is the same as that of Embodiment 1 except that the nitrogen flow rate is 10 mL / min.

[0088] Example 5

[0089] This embodiment provides a method for applying a chromium nitride coating on the surface of a silicone rubber mold. The application method is the same as that of Embodiment 1 except that the nitrogen flow rate is 90 mL / min.

[0090] Example 6

[0091] This embodiment provides a method for applying a chromium nitride coating on the surface of a silicone rubber mold. The application method is the same as that of Embodiment 1 except that the target voltage in the magnetron sputtering is 200V.

[0092] Example 7

[0093] This embodiment provides a method for applying a chromium nitride coating on the surface of a silicone rubber mold. The application method is the same as that of Embodiment 1 except that the target voltage in the magnetron sputtering is 700V.

[0094] Comparative Example 1

[0095] This comparative example provides a method for applying a chromium nitride coating on the surface of a silicone rubber mold. The application method is the same as that of Example 1 except that the thickness of the chromium nitride coating is 0.1 μm.

[0096] Comparative Example 2

[0097] This comparative example provides a method for applying a chromium nitride coating on the surface of a silicone rubber mold. The application method is the same as that of Example 1 except that the thickness of the chromium nitride coating is 0.7 μm.

[0098] Comparative Example 3

[0099] This comparative example provides a method for applying a chromium nitride coating on the surface of a silicone rubber mold, the method comprising:

[0100] After the silicone rubber mold is subjected to sandblasting, polishing and cleaning in sequence, a Teflon coating with a thickness of 20 μm is sprayed on the surface of the silicone rubber mold using a spray gun;

[0101] The grit used in the sandblasting process includes brown corundum with a particle size of 100 mesh; the distance between the silicone rubber mold and the sandblasting nozzle in the sandblasting process is 130 mm; the pressure of the sandblasting process is 0.5 MPa, and the flow rate is 8 L / min; the angle of the nozzle in the sandblasting process is 68°;

[0102] The polishing liquid used in the polishing process is a water-soluble polishing liquid; the cleaning process includes an ultrasonic cleaning process; the frequency of the ultrasonic wave in the ultrasonic cleaning process is 23KHz; the cleaning liquid used in the cleaning process includes a water-based cleaning agent; the temperature of the cleaning process is 60°C and the time is 40 minutes;

[0103] The silicone rubber mold is made of P20 mold steel;

[0104] Then, a curing treatment is carried out at a temperature of 380° C. for 60 minutes.

[0105] Observe with naked eyes the demoulding conditions of the products prepared by the silicone rubber molds treated in the above embodiments and comparative examples under the conditions of a vulcanization temperature of 140° C., a vulcanization pressure of 8 MPa, and a vulcanization time of 1200 s;

[0106] The Vickers hardness test method was used to test the wear resistance of the silicone rubber molds after the above-mentioned embodiments and comparative examples were treated. The specific steps were as follows: a regular tetrahedral diamond indenter with an angle of 136° was used to press into the sample surface under a test force of 98N, and the test force was removed after maintaining for 5 to 10 seconds. The diagonal length of the indentation was then measured to obtain the hardness of the material.

[0107] The wear resistance of the silicone rubber molds after the above-mentioned embodiments and comparative examples was tested using a friction and wear tester in a reciprocating cycle mode, and the process was as follows:

[0108] (1) Prepare test equipment and specimens: Use a wear tester to conduct the test;

[0109] (2) Test conditions: number of reciprocating cycles N = 3600 times; external load 10 N, relative slip speed V = 6 mm / s, reciprocating distance 5 mm;

[0110] (3) Conduct the test: Install the prepared specimen on the wear testing machine and start the test;

[0111] (4) Analyze the test results: After the test, measure the weight loss of the sample, that is, the reduction in the coating, to evaluate the wear resistance of the coating. By comparing the weight loss under different conditions, the wear resistance of the coating can be evaluated.

[0112] Whether the product is completely demoulded, the Vickers hardness and wear resistance of the silicone rubber mold are shown in Table 1.

[0113] Table 1

[0114]

[0115] From Table 1 we can see that:

[0116] (1) It can be seen from Examples 1 to 3 that the method for applying the chromium nitride coating on the surface of the silicone rubber mold provided by the present invention greatly improves the wear resistance and hardness of the silicone rubber mold, and when the silicone rubber mold is used to prepare a product, the product can be completely demoulded;

[0117] (2) Combining Example 1 with Examples 4 to 5, it can be seen that in Example 4, the nitrogen flow rate is relatively small, and the deposited film layer formed on the surface of the silicone rubber mold is mainly Cr and Cr2N. Therefore, the Vickers hardness of the silicone rubber mold is only 850 HV, the wear resistance is poor, and the friction coefficient μ is max and μ 稳定值The nitrogen flow rate in Example 5 is relatively large, and the deposited film layer formed on the surface of the silicone rubber mold is mainly CrN and Cr2N. Therefore, the Vickers hardness of the silicone rubber mold is still relatively small compared with Example 1, which is 1500 HV, and the wear resistance is also smaller than that of Example 1.

[0118] (3) Combining Example 1 with Examples 6 to 7, it can be seen that the target voltage in magnetron sputtering in Example 6 is relatively small, which will result in a thinner chromium nitride coating. The Vickers hardness of the silicone rubber mold is 1100 HV, the wear resistance is poor, and the friction coefficient μ is max is 0.45, μ 稳定值 is 0.42, which is smaller than that in Example 1, and the number of cycles at the maximum value of μ and the number of cycles at the stable value of μ are both lower; in Example 7, the target voltage in magnetron sputtering is larger, and the Vickers hardness of the silicone rubber mold is increased to 1300 HV, but the wear resistance is still poor, and the friction coefficient μ is max and μ 稳定值 Both the number of cycles and the number of cycles are smaller than those in Example 1;

[0119] (4) It can be seen from Example 1 and Comparative Examples 1 to 2 that the thickness of the chromium nitride coating in Comparative Example 1 is relatively thin, the surface finish of the mold is poor, the product cannot be completely demolded, the Vickers hardness is only 700 HV, the wear resistance is poor, and the friction coefficient μ max Only 0.38, μ 稳定值 The maximum value of μ is only 0.32, the number of cycles is only 500 / times, and the number of cycles is only 850 / times when μ is stable, which cannot play a protective role; in Comparative Example 2, the thickness of the chromium nitride coating is thicker, the Vickers hardness of the silicone rubber mold is 1900HV, and the wear resistance is significantly improved, but the friction between the mold and the product is increased, and the friction coefficient μ max is 0.70, μ 稳定值 It is 0.66, and the number of cycles at the maximum value of μ and the number of cycles at the stable value of μ are also high, but it will cause the product to be unable to be completely demoulded;

[0120] (5) It can be seen from Example 1 and Comparative Example 3 that in Comparative Example 3, a Teflon coating with a thickness of 20 μm is sprayed on the surface of the silicone rubber mold. Although the product can be completely demolded, the Vickers hardness of the silicone rubber mold is only 70 HV, and the Teflon coating is very easy to fall off and is severely worn, resulting in a short service life of the mold.

[0121] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for applying a chromium nitride coating on the surface of a silicone rubber mold, characterized in that: The application method comprises: A chromium nitride coating with a thickness of 0.3 to 0.5 μm is sprayed on the surface of a silicone rubber mold by a magnetron sputtering method to improve the demoulding property of the silicone rubber mold.

2. The application method according to claim 1, characterized in that: The material of the silicone rubber mold includes any one of P20 mold steel, S50C mold steel, 718H mold steel or S136 mold steel.

3. The application method according to claim 1 or 2, characterized in that: The purity of the sputtering gas argon in the magnetron sputtering is ≥99.99%; Preferably, the flow rate of the argon gas is 20 to 80 mL / min; Preferably, the working pressure of the argon gas is 0.2-0.8 MPa.

4. The application method according to any one of claims 1 to 3, characterized in that: The purity of the reactive gas nitrogen in the magnetron sputtering is ≥99.999%; Preferably, the nitrogen flow rate is 20 to 80 mL / min; Preferably, the working pressure of the nitrogen is 0.2-0.8 MPa.

5. The application method according to any one of claims 1 to 4, characterized in that: The vacuum degree of the deposition chamber in the magnetron sputtering is 2×10 -3 ~7×10 -3 MPa; Preferably, the purity of the chromium target in the magnetron sputtering is ≥ 99.5%; Preferably, the temperature of the silicone rubber mold during magnetron sputtering is 200-350°C; Preferably, the distance between the chromium target and the silicone rubber mold is 20-100 mm.

6. The application method according to any one of claims 1 to 5, characterized in that: The target voltage in the magnetron sputtering is 300-600V; the target current density is 10-50mA / cm 2 .

7. The application method according to any one of claims 1 to 6, characterized in that: Before spraying the chromium nitride coating, the silicone rubber mold is cleaned, polished and sandblasted in sequence.

8. The application method according to claim 7, characterized in that: The cleaning process includes ultrasonic cleaning process; Preferably, the frequency of the ultrasonic wave in the ultrasonic cleaning process is 20 to 30 KHz; Preferably, the cleaning liquid used in the cleaning process includes a water-based cleaning agent; Preferably, the cleaning temperature is 40-70°C; Preferably, the cleaning process takes 25 to 50 minutes.

9. The application method according to claim 7, characterized in that: The polishing liquid used in the polishing process is a water-soluble polishing liquid; Preferably, the grit used in the sandblasting process includes brown corundum with a particle size of 80 to 120 mesh; Preferably, the distance between the silicone rubber mold and the sandblasting nozzle during the sandblasting process is 100 to 200 mm; Preferably, the pressure of the sandblasting treatment is 0.2-0.8 MPa; Preferably, the flow rate of the sandblasting treatment is 5 to 15 L / min; Preferably, the angle of the nozzle in the sandblasting process is 60-75°.

10. The application method according to any one of claims 1 to 9, characterized in that: The application method comprises: After the silicone rubber mold is cleaned, polished and sandblasted in sequence, a chromium nitride coating with a thickness of 0.3 to 0.5 μm is sprayed on the surface of the silicone rubber mold by a magnetron sputtering method to improve the demoulding property of the silicone rubber mold; The cleaning process includes ultrasonic cleaning process; the frequency of the ultrasonic wave in the ultrasonic cleaning process is 20 to 30 KHz; the cleaning liquid used in the cleaning process includes a water-based cleaning agent; the temperature of the cleaning process is 40 to 70° C., and the time is 25 to 50 minutes; the polishing liquid used in the polishing process is a water-soluble polishing liquid; The grit used in the sandblasting process includes brown corundum with a particle size of 80 to 120 meshes; the distance between the silicone rubber mold and the sandblasting nozzle in the sandblasting process is 100 to 200 mm; the pressure of the sandblasting process is 0.2 to 0.8 MPa, and the flow rate is 5 to 15 L / min; the angle of the nozzle in the sandblasting process is 60 to 75°; The material of the silicone rubber mold includes any one of P20 mold steel, S50C mold steel, 718H mold steel or S136 mold steel; The purity of the sputtering gas argon in the magnetron sputtering is ≥99.99%; the flow rate of the argon is 20-80 mL / min; the working pressure of the argon is 0.2-0.8 MPa; The purity of the reactive gas nitrogen in the magnetron sputtering is ≥99.999%; the nitrogen flow rate is 20-80 mL / min; the working pressure of the nitrogen is 0.2-0.8 MPa; The vacuum degree of the deposition chamber in the magnetron sputtering is 2×10 -3 ~7×10 -3 MPa; the purity of the chromium target in the magnetron sputtering is ≥99.5%; the temperature of the silicone rubber mold in the magnetron sputtering is 200-350°C; the distance between the chromium target and the silicone rubber mold is 20-100mm; The target voltage in the magnetron sputtering is 300-600V; the target current density is 10-50mA / cm 2 .

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