UV fission ink for cigarette box outer packaging and preparation method thereof

Abstract

The present application relates to the field of inks, and discloses a UV fission ink for cigarette box outer packaging and a preparation method thereof. A UV fission ink for cigarette box outer packaging is prepared from the following raw materials in weight percentage: 32-50% polyurethane acrylate, 30-40% functional monomer, 6-10% active amine, 4-8% photoinitiator, 6-8% fission regulator, 2-4% polyethylene wax, 0.5-1% defoamer, 1.5-3% leveling agent; the fission regulator is made of fumed silica, polydipentaerythritol hexaacrylate, silane coupling agent and dispersant. The UV fission ink prepared in the present application maintains good fluidity, and the irregular wrinkle structure or pattern edge formed by printing is not easy to deform, has good three-dimensional sense and clear lines, and the wrinkle structure or pattern edge is not easy to change color and fall off.

Description

Technical Field

[0001] The present application relates to the field of inks, and more specifically, to a UV fission ink for cigarette box outer packaging and a preparation method thereof. Background Art

[0002] In order to enhance the texture of the outer packaging of cigarette boxes and provide better protection for them, multiple layers of base ink are printed on the surface of the outer packaging of cigarette boxes through a printing process. After curing, the multiple layers of base ink are superimposed on each other to form a base ink pattern layer on the surface of the outer packaging of cigarette boxes. Then, a layer of ink is printed on the surface of the base ink pattern layer. After curing, a protective layer with wrinkle structures or patterns such as fine lines, hammer lines, etc. with snowflake or fission textures is formed.

[0003] The ink commonly used for the protective layer is generally formed by curing the ink made of polyurethane resin, diluent, photoinitiator and additives such as polydimethylsiloxane. Polydimethylsiloxane can adjust the viscosity and fluidity of the ink, making the ink easy to print during the printing process; however, the addition of polydimethylsiloxane will make the ink easy to deform during the printing process. When the printed wrinkle structure or pattern is an irregular shape, the edge area of ​​the wrinkle structure or pattern is more likely to deform, thereby reducing the three-dimensional sense and stability of the printed lines of the wrinkle structure or pattern. The edge area of ​​the wrinkle structure or pattern is prone to discoloration and falling off during storage, reducing the protective effect on the base ink. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a UV fission ink for cigarette box outer packaging and a preparation method thereof.

[0005] In the first aspect, the present application provides a UV fission ink for the outer packaging of a cigarette box, which adopts the following technical solution:

[0006] A UV fission ink for cigarette box outer packaging is prepared from the following raw materials in percentage by weight:

[0007]

[0008] The fission regulator is made of fumed silica, polydipentaerythritol hexaacrylate, a silane coupling agent and a dispersant.

[0009] By adopting the above-mentioned technical scheme, the UV fission ink of the present application uses polyurethane acrylate as the main body of the ink, and is compounded with functional monomers, photoinitiators, fission regulators, polyethylene wax, defoaming agents and leveling agents. It can be printed on the surface of the outer packaging of cigarette boxes, and can be cured under the action of photoinitiators. When cured, it can fission to form wrinkle structures and patterns such as fine lines and hammer lines with good three-dimensional sense and stability, avoiding the problem of easy deformation of the edge areas of the wrinkle structure and pattern due to the addition of rheological additives such as polydimethylsiloxane, thereby improving the printing quality and stability of the wrinkle structure or the edge area of ​​the pattern, preventing the problem of discoloration and falling off of the wrinkle structure and the edge area of ​​the pattern during storage, and enhancing the protective effect on the base ink.

[0010] The present application is compounded with a preferably used amount of a fission regulator and polyethylene wax, so that the UV fission ink forms fine particles and a crystal-cured ink layer when solidified, and has a rough and uniform fission texture, thereby forming a three-dimensional wrinkle structure and pattern such as fine lines and hammer lines. The fission regulator is made of fumed silica, polydipentaerythritol hexaacrylate, a silane coupling agent and a dispersant. Under the action of the silane coupling agent, the fumed silica, polydipentaerythritol hexaacrylate and the dispersant form a stable interwoven dispersion system, increase the molecular distance between fumed silica molecules, and can further be dispersed and interwoven with polyurethane acrylate and functional monomers, while improving the fluidity of the UV fission ink, it has good cohesion, so that when the UV fission ink is used to print irregular wrinkle structures and patterns, the fine line edge area formed is not easy to deform, and a stable three-dimensional texture and clear edge lines can be formed, thereby improving the problem of discoloration and shedding of the wrinkle structure and pattern edge area during storage.

[0011] Preferably, the dispersant is composed of trimethylolpropane diallyl ether and 1,4-cyclohexanedimethanol diglycidyl ether in a weight ratio of (1-3):1.

[0012] By adopting the above technical scheme, the dispersant composed of trimethylolpropane diallyl ether and 1,4-cyclohexanedimethanol diglycidyl ether in an optimal dosage ratio can improve the dispersibility of the fission regulator in the UV fission ink, so that the UV fission ink has good fluidity and the edge area is not easy to deform when printing fission to form irregular fine lines and hammer lines and other wrinkle structures and patterns, and has good discoloration resistance and adhesion.

[0013] Preferably, the fission modifier is prepared from the following raw materials in parts by weight:

[0014] 40-50 parts of fumed silica

[0015] 8-12 parts of polydipentaerythritol hexaacrylate

[0016] Silane coupling agent 8-10 parts

[0017] Dispersant 6-8 parts.

[0018] Preferably, the fission modifier is prepared by the following steps:

[0019] The silane coupling agent is added to the fumed silica, and the mixture is kneaded and stirred at a temperature of 80-100° C. Then, polydipentaerythritol hexaacrylate and a dispersant are added, and the mixture is kneaded and stirred evenly to obtain a fission regulator.

[0020] By adopting the above technical solution and optimizing the distribution ratio of each component of the fission regulator and the preparation process, the performance stability of the UV fission ink can be improved, and the problem of easy deformation of the edge area of ​​the wrinkle structure or pattern formed by the fission of the ink during the printing process can be further improved.

[0021] Preferably, the functional monomers are composed of 1,6-hexanediol diacrylate, trimethylolpropane triacrylate and triisopropylsilyl methacrylate in a weight ratio of 1:(1-2):(3-4).

[0022] By adopting the above technical scheme, using 1,6-hexanediol diacrylate, trimethylolpropane triacrylate and triisopropylsilyl methacrylate in a relatively optimal weight ratio as functional monomers, the fluidity and curability of UV fission ink can be improved, and the flexibility and stability of the wrinkle structures and patterns such as fine lines and hammer lines formed can be enhanced.

[0023] Preferably, the active amine is one or a combination of ethylenediamine, propylenediamine and isopropylenediamine.

[0024] By adopting the above technical solution, the above active amine can effectively promote the cross-linking reaction rate of UV fission ink during the curing process, and improve the adhesion, discoloration resistance and stability of the ink layer.

[0025] Preferably, the photoinitiator is KIP150 and / or TPO.

[0026] By adopting the above technical solution, KIP150 and / or TPO as photoinitiators can quickly initiate the polymerization reaction of UV fission ink under UV light irradiation, thereby improving the curing speed and curing efficiency of the ink, thereby reducing the deformation, discoloration and falling off of the wrinkle structures such as fine lines and hammer lines and the edges of the patterns.

[0027] Preferably, the viscosity of the UV fission ink is 800-1200 mPa·s.

[0028] By adopting the above technical solution, the better viscosity makes the UV fission ink have good fluidity during the printing process, and can also improve the stability and three-dimensional sense of wrinkle structures or patterns such as fine lines and hammer lines formed during printing, and reduce the problem of deformation in the edge area.

[0029] In the second aspect, the present application provides a method for preparing UV fission ink for cigarette box outer packaging, using the following technical solution:

[0030] A method for preparing UV fission ink for cigarette box outer packaging, comprising the following steps:

[0031] Adding the fission modifier to part of the functional monomers and mixing them evenly to obtain a mixture A;

[0032] Adding the photoinitiator to part of the functional monomers and mixing them evenly to obtain a mixture B;

[0033] Adding polyurethane acrylate to the remaining functional monomer and mixing them evenly to obtain a mixture C;

[0034] Add mixture A and mixture B into mixture C, mix evenly, then add active amine, polyethylene wax, leveling agent, defoamer and colorant, mix evenly and grind to prepare UV fission ink for cigarette box outer packaging.

[0035] By adopting the above technical solution, the fission regulator is first dispersed evenly, and then mixed and ground with other components to improve the dispersion uniformity of the fission regulator in the ink system, thereby improving the system stability of the prepared UV fission ink.

[0036] Preferably, the grinding rate is 100-300 r / min, and the grinding time is 30-60 min.

[0037] By adopting the above technical solution, the better grinding conditions improve the uniformity and stability of the UV fission ink during the grinding process, improve the fineness and dispersibility of the UV fission ink particles, and further improve the uniformity and stability of the obtained wrinkle structure or pattern.

[0038] In summary, this application has the following beneficial effects:

[0039] 1. The UV fission ink for the outer packaging of cigarette boxes of the present application uses polyurethane acrylate as the main body of the ink, and is compounded with functional monomers, photoinitiators, fission regulators, polyethylene wax, defoamers and leveling agents. It can be printed on the surface of the outer packaging of cigarette boxes and can be cured under the action of photoinitiators. When cured, it can fission to form wrinkle structures and patterns such as fine lines and hammer lines with good three-dimensional sense and stability, avoiding the problem of easy deformation of the edge areas of the wrinkle structure and pattern due to the addition of rheological additives such as polydimethylsiloxane, thereby improving the printing quality and stability of the wrinkle structure or the edge area of ​​the pattern, preventing the problem of discoloration and falling off of the wrinkle structure and the edge area of ​​the pattern during storage, and enhancing the protective effect on the base ink.

[0040] 2. A fission regulator is made of fumed silica, polydipentaerythritol hexaacrylate, silane coupling agent and dispersant, and is compounded with a preferred amount of fission regulator and polyethylene wax. While improving the fluidity of UV fission ink, it has good cohesion, so that when UV fission ink is used to print irregular wrinkle structures and patterns, the fine lines formed at the edge of the ink are not easily deformed, and a stable three-dimensional texture and clear edge lines can be formed, thereby improving the discoloration and shedding problems of the wrinkle structure and pattern edge areas during storage.

[0041] 3. The dispersant composed of trimethylolpropane diallyl ether and 1,4-cyclohexanedimethanol diglycidyl ether in a better dosage ratio can improve the dispersibility of the fission regulator in the UV fission ink, so that the UV fission ink has good fluidity, and the edge area is not easy to deform when printing fission to form irregular fine lines and hammer lines and other wrinkle structures and patterns, and has good discoloration resistance and adhesion.

[0042] 4. The preparation method of the present application improves the dispersion uniformity of the fission regulator in the ink system by first uniformly dispersing the fission regulator, and then mixing and grinding with other components, thereby improving the system stability of the prepared UV fission ink. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the surface of the UV fission ink of this application after printing and curing. DETAILED DESCRIPTION

[0044] The following is combined with Figure 1 The present application is further described in detail with reference to the accompanying drawings and embodiments.

[0045] The following are the sources and specifications of some raw materials of this application. The raw materials used in the preparation examples and embodiments of this application can be obtained from the market, including but not limited to the raw materials of the following models and manufacturers. Raw materials with equivalent performance can be used:

[0046] 1. Polyurethane acrylate: Allnex EBECRYL 5130;

[0047] 2. Polyethylene wax: Honeywell AC 400A;

[0048] 3. Fumed silica: AEROSIL 200;

[0049] 4. Polydipentaerythritol hexaacrylate: CAS No. 29570-58-9, content 98%;

[0050] 5. Trimethylolpropane diallyl ether: CAS No.: 682-09-7, content 99%;

[0051] 6. 1,4-Cyclohexanedimethanol diglycidyl ether: CAS number: 14228-73-0, content 99%.

[0052] Preparation Example of Fission Moderator

[0053] Preparation Example 1

[0054] Preparation Example 1 discloses a fission modifier, which is prepared by the following steps:

[0055] 0.8 kg of vinyl trimethoxysilane as a silane coupling agent was added to 4 kg of fumed silica, and the mixture was kneaded and stirred at a temperature of 80°C for 30 min. Then, 1.2 kg of polydipentaerythritol hexaacrylate and 0.6 kg of a dispersant (composed of 0.3 kg of trimethylolpropane diallyl ether and 0.3 kg of glycidyl methacrylate) were added, and the mixture was kneaded for 30 min. The mixture was kneaded and stirred evenly to obtain a fission regulator.

[0056] Preparation Example 2-3

[0057] The difference between Preparation Example 2-3 and Preparation Example 1 is that the amount of raw materials used and the preparation conditions are different, see Table 1 below for details.

[0058] Table 1 Raw material dosage and preparation conditions of Preparation Examples 1-3

[0059]

[0060]

[0061] Preparation Example 4

[0062] The difference between Preparation Example 4 and Preparation Example 1 is that the dispersant is different. The dispersant in Preparation Example 4 is composed of trimethylolpropane diallyl ether and 1,4-cyclohexanedimethanol diglycidyl ether. The amount of trimethylolpropane diallyl ether is 0.3 kg, and the amount of 1,4-cyclohexanedimethanol diglycidyl ether is 0.3 kg. The rest is the same as Preparation Example 1.

[0063] Preparation Example 5

[0064] The difference between Preparation Example 5 and Preparation Example 1 is that the dispersant in Preparation Example 5 is composed of trimethylolpropane diallyl ether and 1,4-cyclohexanedimethanol diglycidyl ether, the amount of trimethylolpropane diallyl ether used is 0.45 kg, the amount of 1,4-cyclohexanedimethanol diglycidyl ether used is 0.15 kg, and the rest is the same as Preparation Example 1.

[0065] Preparation Comparative Example 1

[0066] The difference between Preparation Comparative Example 1 and Preparation Example 1 is that an equal amount of polydipentaerythritol hexaacrylate is replaced by glycidyl methacrylate, and the rest is the same as Preparation Example 1.

[0067] Example

[0068] Example 1

[0069] Example 1 discloses a UV fission ink for cigarette box outer packaging, which is prepared by the following steps:

[0070] 0.8 kg of the fission modifier prepared in Preparation Example 1 was added to 0.5 kg of a functional monomer (composed of 1,6-hexanediol diacrylate, trimethylolpropane triacrylate and hydroxypropyl acrylate in a weight ratio of 1:1:3), and mixed at 600 r / min for 30 min to prepare a mixture A;

[0071] 0.8 kg of photoinitiator was added to 0.5 kg of functional monomer (composed of 1,6-hexanediol diacrylate, trimethylolpropane triacrylate and hydroxypropyl acrylate in a weight ratio of 1:1:3), and mixed at 600 r / min for 10 min to prepare a mixture B;

[0072] 4 kg of polyurethane acrylate was added to 2.35 kg of functional monomer (composed of 1,6-hexanediol diacrylate, trimethylolpropane triacrylate and hydroxypropyl acrylate in a weight ratio of 1:1:3), and mixed at 600 r / min for 20 min to prepare a mixture C;

[0073] Mixture A and mixture B were added to mixture C and mixed evenly, and then 0.6 kg of ethylenediamine as an active amine, 0.2 kg of polyethylene wax, 0.2 kg of silicone acrylate as a leveling agent and 0.05 kg of silicone defoamer were added and mixed evenly, and ground for 30 minutes at a grinding rate of 100 r / min to obtain UV fission ink for cigarette box outer packaging; the silicone acrylate was TEGO Rad 2100; the silicone defoamer was RP-6053 from Ruike Chemical.

[0074] Example 2-3

[0075] The difference between Example 2-3 and Example 1 is that the amount of raw materials used and the preparation conditions are different, see Table 2 below for details.

[0076] Table 2 Raw material dosage and preparation conditions of Examples 1-3

[0077]

[0078]

[0079] Example 4

[0080] The difference between Example 4 and Example 1 is that the fission modifier is derived from Preparation Example 4, and the rest is the same as Example 1.

[0081] Example 5

[0082] The difference between Example 5 and Example 1 is that the fission modifier is derived from Preparation Example 5, and the rest is the same as Example 1.

[0083] Example 6

[0084] The difference between Example 6 and Example 4 is that the functional monomers are different. The functional monomers in Example 6 are composed of 1,6-hexanediol diacrylate, trimethylolpropane triacrylate and triisopropylsilyl methacrylate in a weight ratio of 1:1:3, and the rest are the same as Example 4.

[0085] Example 7

[0086] The difference between Example 7 and Example 6 is that the functional monomer consists of 1,6-hexanediol diacrylate, trimethylolpropane triacrylate and triisopropylsilyl methacrylate in a weight ratio of 1:2:4, and the rest is the same as Example 6.

[0087] Comparative Example

[0088] Comparative Example 1

[0089] The difference between Comparative Example 1 and Example 1 is that the fission modifier is derived from the preparation of Comparative Example 1, and the rest is the same as Example 1.

[0090] Comparative Example 2

[0091] The difference between Comparative Example 2 and Example 1 is that the fission modifier is fumed silica, and the rest is the same as Example 1.

[0092] Comparative Example 3

[0093] The difference between Comparative Example 3 and Example 1 is that the amount of fission modifier used is 0.95 kg, the amount of polyethylene wax used is 0.05 kg, and the rest is the same as Example 1.

[0094] Comparative Example 4

[0095] The difference between Comparative Example 4 and Example 1 is that the amount of fission modifier used is 0.4 kg, the amount of polyethylene wax used is 0.6 kg, and the rest is the same as Example 1.

[0096] Performance testing

[0097] The following is a performance test of the UV fission ink for cigarette box outer packaging of Examples 1-7 and Comparative Examples 1-4. During the test, the irregular pattern shape to be printed is set according to the required printing, and the UV fission ink is printed using a gravure printing machine, and the printing amount of the UV fission ink is controlled to be 15g / m 2 ,After printing, at 100mW / cm 2 , and cured for 30 seconds under ultraviolet light with a wavelength of 240-365nm to form an irregular pattern layer (see attached Figure 1 ), and then test:

[0098] 1. Irregular pattern edge stereo test

[0099] Use visual inspection to observe the deformation of the edges of the cured irregular pattern and record the test results;

[0100] 2. Sun fastness test

[0101] Refer to the test method in GB / T 22771-2008 to test the light fastness of the irregular pattern layer, and test and record the test results;

[0102] 3. Adhesion test

[0103] Use the hundred-grid test method to test the adhesion of the edge area of ​​the irregular pattern, test and record the test results;

[0104] The following are the performance test data of the UV fission ink for cigarette box outer packaging prepared in Examples 1-7 and Comparative Examples 1-4, see Table 3 below for details.

[0105] Table 3 Performance test data of Examples 1-7 and Comparative Examples 1-4

[0106]

[0107]

[0108] Combining Examples 1-3 and 4-5, Comparative Examples 1-2 and Table 3, it can be concluded that the fission regulator prepared from fumed silica, polydipentaerythritol hexaacrylate and a dispersant of the present application can effectively improve the deformation problem of the UV fission ink, and is suitable for printing wrinkle structures or patterns such as fine lines and hammer lines with irregular shapes. The edge area of ​​the printed wrinkle structure or pattern has good three-dimensional sense and flatness, and is not easy to change color or fall off during storage and use. Compared with Example 1, Example 4 further optimizes the composition and proportion of the dispersant, and the edge flatness of the UV fission ink obtained is improved, and the light resistance grade and adhesion are improved. The grades are all improved, indicating that the optimal usage ratio of trimethylolpropane diallyl ether and 1,4-cyclohexanedimethanol diglycidyl ether as dispersants has a better effect on the dispersion performance of the fission regulator in UV ink; in Comparative Example 1, compared with Example 1, polydipentaerythritol hexaacrylate is replaced by glycidyl methacrylate in equal amounts, and the edges of the UV fission ink obtained have burrs and unevenness, and the light fastness grade and adhesion grade are both reduced; and in Comparative Example 2, compared with Example 1, only fumed silica is used as the fission regulator, and the edges of the UV fission ink obtained have obvious burrs and obvious unevenness, and the light fastness grade and adhesion grade are both significantly reduced.

[0109] Combining Example 4 and Examples 6-7 with Table 3, it can be concluded that the present application further optimizes the functional monomers, and uses 1,6-hexanediol diacrylate, trimethylolpropane triacrylate and triisopropylsilyl methacrylate in a better dosage ratio as functional monomers, which can further improve the light resistance and adhesion of the prepared UV fission ink. This may be because the above-mentioned functional monomers have good synergistic effects, which can improve the fluidity and curing properties of the UV fission ink, thereby improving the flexibility and stability of the edges of the formed wrinkle structures such as fine lines and hammer lines and patterns.

[0110] Combining Example 1 and Comparative Examples 3-4 and Table 3, it can be concluded that the use of a better dosage ratio of fission regulator and polyethylene wax can make the prepared UV fission ink have good fluidity, and the edge area of ​​the printed wrinkle structure or pattern has good three-dimensional sense and flatness, and is not easy to change color and fall off during storage and use. In Comparative Example 3, the fission regulator is increased, and the dosage of polyethylene wax is reduced. The edge of the prepared UV fission ink has burrs and unevenness, and the light resistance level is reduced; while in Comparative Example 4, the dosage of polyethylene wax is increased, and the dosage of fission regulator is reduced. The prepared UV fission ink has serious casting, serious unevenness, and the light resistance level and adhesion level are significantly reduced.

[0111] The viscosity of the UV fission ink prepared in the present application is 800-1200mPa·s. It has good fluidity and good cohesion. When solidified, it can fission to form wrinkle structures and patterns such as fine lines and hammer lines with good three-dimensional sense and stability, avoiding the problem of easy deformation of the edge areas of the wrinkle structure and pattern due to the addition of rheological additives such as polydimethylsiloxane, thereby improving the printing quality and stability of the wrinkle structure or the edge area of ​​the pattern, and preventing the problem of discoloration and falling off of the wrinkle structure and the edge area of ​​the pattern during storage.

[0112] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A UV fission ink for cigarette box outer packaging, characterized in that: Made from the following raw materials in weight percentage: Polyurethane acrylate 32-50% Functional monomer 30-40% Active amine 6-10% Photoinitiator 4-8% Fission modifier 6-8% Polyethylene wax 2-4% Defoamer 0.5-1% Leveling agent 1.5-3%; The fission modifier is prepared from the following raw materials in parts by weight: 40-50 parts of fumed silica 8-12 parts of polydipentaerythritol hexaacrylate Silane coupling agent 8-10 parts Dispersant 6-8 parts; The dispersant is composed of trimethylolpropane diallyl ether and 1,4-cyclohexanedimethanol diglycidyl ether in a weight ratio of (1-3):

1.

2. The UV fission ink for cigarette box outer packaging according to claim 1, characterized in that: The fission modifier is prepared by the following steps: The silane coupling agent is added to the fumed silica, and the mixture is kneaded and stirred at a temperature of 80-100° C. Then, polydipentaerythritol hexaacrylate and a dispersant are added, and the mixture is kneaded and stirred evenly to obtain a fission regulator.

3. The UV fission ink for cigarette box outer packaging according to claim 1, characterized in that: The functional monomers are composed of 1,6-hexanediol diacrylate, trimethylolpropane triacrylate and triisopropylsilyl methacrylate in a weight ratio of 1:(1-2):(3-4).

4. The UV fission ink for cigarette box outer packaging according to claim 1, characterized in that: The active amine is one or a combination of ethylenediamine, propylenediamine and isopropylenediamine.

5. The UV fission ink for cigarette box outer packaging according to claim 1, characterized in that: The photoinitiator is KIP150 and / or TPO.

6. The UV fission ink for cigarette box outer packaging according to claim 1, characterized in that: The viscosity of the UV fission ink is 800-1200 mPa·s.

7. A method for preparing a UV fission ink for cigarette box outer packaging as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: Adding the fission modifier to part of the functional monomers and mixing them evenly to obtain a mixture A; Adding the photoinitiator to part of the functional monomers and mixing them evenly to obtain a mixture B; Adding polyurethane acrylate to the remaining functional monomer and mixing them evenly to obtain a mixture C; Add mixture A and mixture B into mixture C, mix evenly, then add active amine, polyethylene wax, leveling agent and defoaming agent, mix evenly and grind to prepare UV fission ink for cigarette box outer packaging.

8. The method for preparing UV fission ink for cigarette box outer packaging according to claim 7, characterized in that: The grinding rate of the grinding is 100-300 r / min, and the grinding time is 30-60 min.

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