A new material for 5G optical communication ceramic ferrule and a preparation method and application thereof

Abstract

The application belongs to the technical field of ceramic materials, and particularly relates to a new material for a 5G optical communication ceramic ferrule and a preparation method and application thereof. The new material comprises the following raw material components in parts by weight: 70-90 parts of mullite powder; 10-20 parts of feldspar powder; 0.5-5 parts of cooked talc or dolomite powder; and 1-5 parts of zirconium oxide powder. The mullite powder is prepared from aluminum oxide and silicon oxide and has a particle size of less than 100 nm. The new material is obtained by taking nanoscale mullite as the main body, adding appropriate feldspar powder, a small amount of cooked talc or dolomite, and zirconium oxide, and is used in a 5G optical communication ceramic ferrule. The new material has good stability, high precision, excellent anti-aging performance, and low cost, and is an ideal material for a new generation of ceramic ferrules.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ceramic materials, and particularly relates to a new material for a 5G optical communication ceramic ferrule and a preparation method and application thereof. BACKGROUND

[0002] The 5G optical communication ceramic ferrule, also known as an optical fiber ceramic ferrule or a ceramic ferrule body, is a key component in an optical fiber connector plug. It is used to realize physical butt joint of optical fibers, ensure that two end faces of the optical fibers can be accurately butt jointed, so that optical signals can be continuously transmitted to form an optical path. In a 5G optical communication system, the ceramic ferrule, as a core component of an optical fiber connector, plays a vital role.

[0003] At present, the ceramic ferrule is mainly prepared by injection molding of zirconium dioxide (ZrO2) powder material. The zirconium dioxide material has the characteristics of high hardness, high melting point and wear resistance, so that the obtained ceramic ferrule can maintain high-precision butt joint effect. However, with the continuous development of solid-state battery technology, the market demand for zirconia is increasing, which makes its price rise continuously. Since the zirconium dioxide used by the ceramic ferrule is in a large amount, it directly affects the manufacturing cost of the ceramic ferrule. At the same time, although the zirconium dioxide has excellent mechanical properties and chemical stability, its tetragonal phase is easily affected by the external high-temperature and high-humidity environment to transform into a monoclinic phase, which easily leads to volume shrinkage and stress generation, not only affecting the anti-aging performance of the zirconium dioxide ceramic material and shortening the service life, but also affecting the precision and stability of the ceramic ferrule after phase transformation, and to some extent, increasing the optical fiber loss and greatly reducing the performance. Therefore, it is necessary to seek a new type of ceramic powder that can replace zirconium dioxide and be applied to the 5G optical communication ceramic ferrule. SUMMARY

[0004] In view of the deficiencies of the prior art, the application provides a new material for a 5G optical communication ceramic ferrule and a preparation method and application thereof. The new material takes mullite as the main body, and the obtained new material is used in the 5G optical communication ceramic ferrule, has good stability, high precision, excellent anti-aging performance, long service life and low cost, and can effectively solve the deficiencies of the prior art.

[0005] In order to achieve the above-mentioned purpose, the application provides the following technical scheme:

[0006] The first object of the application is to provide a new material for a 5G optical communication ceramic ferrule, which comprises the following raw material components in parts by weight:

[0007] 70-90 parts of mullite powder;

[0008] 10-20 parts of feldspar powder;

[0009] 0.5-5 parts of ground talc or dolomite powder;

[0010] 1-5 parts of zirconia powder;

[0011] The mullite powder is prepared from aluminum oxide and silicon oxide, and has a particle size of less than 100 nm.

[0012] Specifically, the particle size of the feldspar powder is 1-10 pm;

[0013] The particle size of the ground talc or dolomite powder is 0.5-3 pm;

[0014] The particle size of the zirconia powder is 0.1-1 pm.

[0015] Mullite has high hardness, melting point and thermal stability, excellent acid and alkali resistance, and good insulation, and can maintain the original physical properties in a high-temperature environment, improving the high-temperature stability, wear resistance, corrosion resistance and insulation of the material; Feldspar contains barium and potassium components, which can effectively reduce the sintering temperature, prevent abnormal grain growth of the material, optimize the internal structure of the material, and reduce the attenuation of optical signals in the transmission process; Ground talc or dolomite can enhance the density and precision of ceramics, while reducing the thermal expansion and contraction performance of the product and improving the stability to temperature changes; Zirconia has high chemical stability, high hardness and wear resistance, high toughness and electrical insulation, and is a good raw material for ceramic ferrules, but due to its high cost, a small amount of zirconia is added as a reinforcing agent in the present application, which can enhance the performance of the material while achieving the dispersion effect. Therefore, the new material of the present application mainly contains nanoscale mullite, and a proper amount of feldspar powder, a small amount of ground talc or dolomite, and zirconia are added, so that the new material has small particle size and excellent overall performance, and is used for preparing 5G optical communication ceramic ferrules, which have good density, high precision, excellent anti-aging performance, and can greatly reduce the cost.

[0016] Further, in the above technical solution, the preparation method of the mullite powder is as follows: aluminum oxide and silicon oxide are mixed, a small amount of water is added and ground for 40-50 min, then pressed into a shape and placed in a sintering furnace, the temperature is raised to 1200-1400 DEG C for pre-sintering for 20-30 min, then the temperature is raised to 1600-1700 DEG C for sintering for 30-50 min, and then cooled, crushed, ground and sieved to obtain the mullite powder. The mullite powder used in the present application is obtained by self-preparation, and has small and uniform particle size and stable performance, so there is no need to worry about the instability of market materials.

[0017] Further, in the above technical solution, the molar ratio of the aluminum oxide and the silicon oxide is 2-3:1-2.

[0018] Further, in the technical scheme, the feldspar powder is a mixture of barium feldspar and potassium feldspar in a mass ratio of 3-5:1. In the technical scheme, the feldspar is mainly barium feldspar, which can reduce the alkali metal elements such as potassium and sodium brought by potassium feldspar, improve the physical and chemical properties of the material, and at the same time, utilize the characteristics of barium feldspar such as low linear expansion coefficient, small dielectric loss at high temperature, high strength, and aging resistance, to ensure the high thermal stability of the material and the transmission quality of the signal, and prolong the service life; by adding an appropriate amount of potassium feldspar, the sintering temperature of the material can be significantly reduced, the energy consumption and cost can be reduced, and the internal grain structure of the material can be optimized to a certain extent, and the attenuation of the optical signal can be reduced.

[0019] Further, in the technical scheme, the preparation method of the barium feldspar is as follows: after mixing aluminum oxide, silicon oxide and barium carbonate uniformly, a small amount of water is added and ground for 40-50 min, then the mixture is pressed into a square and stacked in a sintering furnace, the temperature is raised to 950-1050 DEG C for primary sintering, the sintering time is 60-80 min, then the temperature is raised to 1180-1220 DEG C for secondary sintering, the sintering time is 30-50 min, after cooling, crushing, grinding and screening, the barium feldspar powder is obtained.

[0020] Further, in the technical scheme, the molar ratio of the aluminum oxide, the silicon oxide and the barium carbonate is 1:2:1-1.2.

[0021] Further, in the technical scheme, the zirconium oxide is tetragonal zirconium oxide.

[0022] The second object of the application is to provide a preparation method of a new material for a 5G optical communication ceramic ferrule, which comprises the following steps: weighing mullite powder, feldspar powder, cooked talc or dolomite powder, and zirconium oxide powder according to the proportion, adding them into a grinder, then adding water with a volume of 0.5-1.2 times of the powder, grinding at 500-800 rpm until the powder D 50 After 0.2-0.3 μm, after spray drying, the new material powder is obtained. Specifically, the feeding speed of spray drying is 5-20 mL / min, and the hot air temperature is 150-300 DEG C.

[0023] The application also provides application of a new material for a 5G optical communication ceramic ferrule, and a method for preparing the 5G optical communication ceramic ferrule, which comprises the following steps: mixing a new material powder, a high-molecular thermoplastic resin, a dispersing agent and a lubricant in a mixer at a temperature of 150-180 DEG C for 90-120 min, granulating the mixture into injection molding particles with a diameter of 2 mm and a length of 2 mm, and then injecting the particles into a ferrule mold in a ceramic injection molding machine at a temperature of 150-180 DEG C and a pressure of 50 MPa at a speed of 80-100 mm / s to obtain a ferrule blank, and finally sintering the ferrule blank at a temperature of 1250-1350 DEG C for 10-15 h after defatting at a temperature of 400-550 DEG C for 3-5 h to obtain the 5G optical communication ceramic ferrule.

[0024] Further, in the technical solution, the mass ratio of the new material powder, the high-molecular thermoplastic resin, the dispersing agent and the lubricant is 80-90:6-15:2-3:2-4; the high-molecular thermoplastic resin is an acrylic resin; the dispersing agent is stearic acid or oleic acid; and the lubricant is microcrystalline paraffin wax.

[0025] Compared with the prior art, the application has the following beneficial effects:

[0026] The application can improve the strength, anti-aging performance and fiber loss performance of the material, reduce the sintering temperature, save energy and protect the environment by optimizing the formula, taking nano-mullite as the main component, adding an appropriate amount of feldspar while controlling the proportion of barium feldspar and potassium feldspar, adding a small amount of cooked talc or dolomite to enhance the ceramic density and precision and reduce the thermal expansion and contraction performance of the product and improve the stability to temperature change, and adding a small amount of zirconia as a reinforcing phase to improve the dispersion effect and play a reinforcing role.

[0027] The raw materials used in the application have a wide source, good environmental adaptability, easy grinding, excellent processing performance, good density and precision, high bending strength, excellent anti-aging and fiber loss performance, excellent overall performance, long service life, and can greatly reduce the production cost, and is an ideal material for a new generation of ceramic ferrules. DETAILED DESCRIPTION

[0028] The experimental methods in the following examples are conventional methods unless otherwise specified. The raw materials involved in the following examples are ordinary commercially available products and can be purchased on the market.

[0029] The above technical features of the present application and the technical features described in detail below (such as the examples) can be combined with each other to form new or preferred technical solutions.

[0030] The raw materials involved in the embodiments of the present application are either existing commercially available products or can be prepared according to existing methods, and the test method is an industry method.

[0031] Embodiment 1

[0032] A new material for a 5G optical communication ceramic ferrule, including the following raw material components by weight:

[0033] 70 parts of mullite powder;

[0034] 10 parts of feldspar powder;

[0035] 2 parts of talc powder;

[0036] 3 parts of tetragonal zirconia powder;

[0037] The preparation method of the mullite powder is as follows: aluminum oxide and silicon oxide are mixed in a molar ratio of 3:2, a small amount of water is added for grinding for 40 minutes, and then the mixture is pressed into a shape and placed in a sintering furnace, the temperature is increased to 1200 DEG C for pre-sintering for 30 minutes, then the temperature is increased to 1600 DEG C for sintering for 50 minutes, and then the mixture is cooled, broken, ground and sieved to obtain mullite powder with a particle size of less than 100 nm;

[0038] The preparation method of the barium feldspar is as follows: aluminum oxide, silicon oxide and barium carbonate are mixed uniformly in a molar ratio of 1:2:1, a small amount of water is added for grinding for 40 minutes, and then the mixture is pressed into a square shape and stacked in a sintering furnace, the temperature is increased to 1000 DEG C for primary sintering, the sintering time is 80 minutes, then the temperature is increased to 1200 DEG C for secondary sintering, the sintering time is 50 minutes, and then the mixture is cooled, broken, ground and sieved to obtain barium feldspar powder with a particle size of 1-10 microns. Then the obtained barium feldspar powder and potassium feldspar powder with a particle size of 1-10 microns are mixed to obtain feldspar powder in a mass ratio of 3:1;

[0039] The particle size of the talc powder is 0.5-3 microns;

[0040] The particle size of the zirconia powder is 0.1-1 micron;

[0041] The preparation method comprises the following steps:

[0042] The mullite powder, feldspar powder, talc powder and tetragonal zirconia powder are weighed according to the proportion and added into a grinding machine, then water with a volume of 0.8 times that of the powder is added, and the mixture is ground at 500 rpm until the powder D 50After spray drying at a feeding speed of 5 mL / min and a hot air temperature of 150 DEG C, a new material powder is obtained.

[0043] Example 2

[0044] A new material for a 5G optical communication ceramic ferrule comprises the following raw material components by weight:

[0045] 80 parts of mullite powder;

[0046] 15 parts of feldspar powder;

[0047] 3 parts of talc powder;

[0048] 4 parts of tetragonal zirconia powder;

[0049] The preparation method of the mullite powder is as follows: alumina and silicon oxide are mixed according to a molar ratio of 2.5:1.5, a small amount of water is added for grinding for 45 min, and then the mixture is pressed into a shape and placed in a sintering furnace to increase the temperature to 1300 DEG C for pre-sintering for 25 min, and then the temperature is increased to 1650 DEG C for sintering for 40 min, and then the mixture is cooled, broken, ground and sieved to obtain mullite powder with a particle size of less than 100 nm;

[0050] The preparation method of the barium feldspar is as follows: alumina, silicon oxide and barium carbonate are uniformly mixed according to a molar ratio of 1:2:1.1, a small amount of water is added for grinding for 45 min, and then the mixture is pressed into a square shape and stacked in a sintering furnace to increase the temperature to 1000 DEG C for one-step sintering for 70 min, and then the temperature is increased to 1180 DEG C for two-step sintering for 40 min, and then the mixture is cooled, broken, ground and sieved to obtain barium feldspar powder with a particle size of 1-10 μm. Then the obtained barium feldspar powder and potassium feldspar powder with a particle size of 1-10 μm are mixed to obtain feldspar powder according to a mass ratio of 4:1;

[0051] The talc powder has a particle size of 0.5-3 μm;

[0052] The zirconia powder has a particle size of 0.1-1 μm;

[0053] The preparation method comprises the following steps:

[0054] The mullite powder, the feldspar powder, the talc powder and the tetragonal zirconia powder are weighed according to the proportion and then added into a grinder, and then water with a volume of 1 times that of the powders is added, and the mixture is ground at 700 rpm until the powder D 50 After spray drying at a feeding speed of 10 mL / min and a hot air temperature of 200 DEG C, a new material powder is obtained.

[0055] Example 3

[0056] A new material for 5G optical communication ceramic ferrule, by weight parts, comprising the following raw material components:

[0057] Mullite powder 90 parts;

[0058] Feldspar powder 20 parts;

[0059] Dolomite powder 5 parts;

[0060] Tetragonal zirconium oxide powder 5 parts;

[0061] The preparation method of mullite powder is: mixing alumina and silicon oxide in a mass ratio of 3:2, adding a small amount of water and grinding for 50 min, pressing into a shape, then putting it into a sintering furnace, increasing the temperature to 1400℃ for pre-sintering for 20 min, then increasing the temperature to 1700℃ for sintering for 30 min, cooling, crushing, grinding and sieving to obtain mullite powder with a particle size of less than 100 nm;

[0062] The preparation method of barium feldspar is: mixing alumina, silicon oxide and barium carbonate in a molar ratio of 1:2:1.2, adding a small amount of water and grinding for 50 min, pressing into a cube, then stacking it into a sintering furnace, increasing the temperature to 1050℃ for one-step sintering, sintering time is 60 min, then increasing the temperature to 1220℃ for two-step sintering, sintering time is 30 min, cooling, crushing, grinding and sieving to obtain barium feldspar powder with a particle size of 1-10μm. Then the obtained barium feldspar powder and potassium feldspar powder with a particle size of 1-10μm are mixed to obtain feldspar powder in a mass ratio of 5:1;

[0063] The particle size of dolomite powder is 0.5-3μm;

[0064] The particle size of zirconium oxide powder is 0.1-1μm;

[0065] The preparation method comprises the following steps:

[0066] The mullite powder, feldspar powder, dolomite powder and tetragonal zirconium oxide powder are weighed according to the proportion and added into a grinder, then water with a volume of 1.2 times of the powder is added, and the powder is ground at 800rpm to a powder D 50 After the particle size in the range of 0.2-0.3μm, the powder is obtained by spray drying at a feeding speed of 20mL / min and a hot air temperature of 300℃.

[0067] Comparative Example 1

[0068] A new material for 5G optical communication ceramic ferrule, which is different from Example 1 in that the mullite powder used is a commercially available product with a particle size of more than 5μm, and the preparation method is the same.

[0069] Comparative Example 2

[0070] A new material for a 5G optical communication ceramic ferrule, which is different from Example 1 in that the feldspar is all potassium feldspar, and the preparation method is the same.

[0071] Comparative Example 3

[0072] A new material for a 5G optical communication ceramic ferrule, which is different from Example 1 in that the feldspar is all barium feldspar, and the preparation method is the same.

[0073] Comparative Example 4

[0074] A new material for a 5G optical communication ceramic ferrule, which is different from Example 1 in that no talc powder is added.

[0075] Comparative Example 5

[0076] A new material for a 5G optical communication ceramic ferrule, which is different from Example 1 in that no zirconia powder is added.

[0077] Comparative Example 6

[0078] A new material for a ceramic ferrule, which comprises the following raw material components by weight:

[0079] 83 parts of tetragonal zirconia powder;

[0080] 2 parts of talc powder;

[0081] The particle size of the zirconia powder is 0.1-1 μm; the particle size of the talc powder is 0.5-3 μm, and the preparation method is as follows: the zirconia powder and the talc powder are weighed according to the ratio and added to a grinder, then water with a volume of 0.8 times the powder is added, and the powder is ground at 500 rpm until the powder D50 is in the range of 0.2-0.3 μm, then spray drying is carried out at a feeding speed of 5 mL / min and a hot air temperature of 150°C, and finally the new material powder is obtained.

[0082] Test Example

[0083] The new material powder prepared in Examples 1-3 and Comparative Examples 1-6 is used for the preparation of 5G optical communication ceramic ferrules, and the specific preparation method is as follows: the new material powder is mixed with acrylic resin, stearic acid and microcrystalline wax in a mass ratio of 85:10:2:3, and then placed in a mixing machine at a temperature of 170°C for mixing for 100 min, and then granulated into injection molding particles with a diameter of 2 mm and a length of 2 mm, and then placed in a ceramic injection molding machine, and injected into a ferrule mold at a temperature of 170°C, a pressure of 50 MPa and a speed of 100 mm / s to obtain a SC ferrule blank, and finally after 5h of debinding at 500°C, sintering at 1300°C for 15h to obtain a 5G optical communication ceramic ferrule. Then the density, hardness, mechanical properties, anti-aging properties, etc. of the obtained ceramic ferrule are detected, and the results are shown in Table 1. Among them, the density is tested by the drainage method; the mechanical properties are tested by a universal tensile testing machine; the hardness is measured by a Mohs hardness tester; the anti-aging performance test is to measure the density change rate of the ceramic ferrule after soaking in an acidic solution with a pH of 2 for 4h and then sintering at a high temperature of 1350°C; the concentricity qualified rate is the percentage of the number of ceramic ferrules with a concentricity less than 2μm and no cracks in 1000 ceramic ferrule samples; the optical fiber loss is detected according to the ISO / IEC 11801-2 standard, and the insertion loss and return loss are detected, and 100 ceramic ferrule samples are detected and averaged.

[0084] Table 1 Performance results

[0085]

[0086] From the results in Table 1, it can be seen that the new material prepared by the formula of the present application has excellent comprehensive performance, and when used for 5G optical communication ceramic ferrules, it has good density and precision, high bending strength, and excellent anti-aging and optical fiber loss performance. The new material has a wide source of raw materials and low cost, and can be used as a new type of ceramic ferrule material.

[0087] In the comparative example 1, the commercially available mullite is used, and the density is poor due to the unstable source and the too large particle size, thereby affecting the overall performance of the subsequent; in the comparative example 2, only the potassium feldspar is used, and the potassium feldspar is too much, and the crystal phase change of the potassium and sodium alkali metal is easy to occur at high temperature, the expansion coefficient is increased, the stability of the ceramic ferrule to acid and alkali substances and the size under high temperature environment is affected, and the overall performance of the ceramic ferrule is directly affected; in the comparative example 3, only the barium feldspar is used, although the overall performance of the obtained ceramic ferrule is relatively excellent, but a higher temperature is needed in the processing process, the energy consumption is greatly improved, and the optical fiber loss is relatively large because the barium feldspar does not optimize the internal structure of the ferrule; in the comparative example 4, although the overall performance is better without adding the talc powder, the concentricity qualification rate is greatly reduced, and the precision is relatively poor; in the comparative example 5, the overall performance of the ceramic ferrule obtained by not adding the zirconia is reduced, which shows that a small amount of zirconia can play a phase increasing role; in the comparative example 6, the ceramic ferrule prepared by taking the zirconia as the main raw material has higher density and strength, but the anti-aging performance is poor, which not only affects the service life, but also has high cost.

[0088] In summary, the self-made nano mullite is used as the main component, and the appropriate barium feldspar and potassium feldspar composite powder, a small amount of talc or dolomite and zirconia are added, and the new material obtained is used for manufacturing the 5G optical communication ceramic ferrule, and the new material has good density, high precision, anti-aging performance and low optical fiber loss, and has a longer service life and low cost, and has certain advantages compared with the existing zirconia ferrule, and can be used as a new ideal material of the 5G optical communication ceramic ferrule.

[0089] Finally, it should be emphasized that the above-mentioned is only the preferred embodiment of the present application, and is not used to limit the present application, and the present application can have various changes and modifications for the person skilled in the art, and any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A powder material for a 5G optical communication ceramic ferrule, characterized in that, The powder material comprises the following raw material components by weight parts: Mullite powder 70-90 parts; Feldspar powder 10-20 parts; Cooked talc or dolomite powder 0.5-5 parts; Zirconia powder 1-5 parts; The mullite powder is prepared from alumina and silica, and the particle size is less than 100 nm; The feldspar powder is a mixture of barium feldspar and potassium feldspar in a mass ratio of 3-5:

1. 2.The powder material for a 5G optical communication ceramic ferrule according to claim 1, wherein, The preparation method of the mullite powder is as follows: alumina and silica are mixed, a small amount of water is added for grinding for 40-50 min, and then the mixture is pressed into a shape and placed in a sintering furnace, the temperature is raised to 1200-1400℃ for pre-sintering for 20-30 min, then the temperature is raised to 1600-1700℃ for sintering for 30-50 min, and after cooling, the mixture is broken, ground and sieved to obtain the mullite powder. 3.The powder material for 5G optical communication ceramic ferrule of claim 1, wherein, The molar ratio of the alumina and the silica is 2-3:1-2. 4.The powder material for a 5G optical communication ceramic ferrule according to claim 1, wherein, The preparation method of the barium feldspar is as follows: alumina, silica and barium carbonate are mixed uniformly, a small amount of water is added for grinding for 40-50 min, and then the mixture is pressed into a square shape and stacked in a sintering furnace, the temperature is raised to 950-1050℃ for first sintering, the sintering time is 60-80 min, then the temperature is raised to 1180-1220℃ for second sintering, the sintering time is 30-50 min, and after cooling, the mixture is broken, ground and sieved to obtain the barium feldspar powder.

5. The powder material according to claim 4, wherein, The molar ratio of the alumina, the silica and the barium carbonate is 1:2:1-1.

2.

6. The powder material according to claim 5, wherein, The zirconia is tetragonal zirconia.

7. The method of claim 1-6, wherein the method further comprises the step of: The preparation method comprises the following steps: weighing mullite powder, feldspar powder, cooked talc or dolomite powder and zirconia powder according to a proportion, adding the powders into a grinder, then adding water with a volume of 0.5-1.2 times of the powders, and grinding at 500-800 rpm until the powders have a D 50 After spray drying, the powder material is obtained in the range of 0.2-0.3 μm. ​ 8. Use of a powder material according to any one of claims 1 to 6 for a 5G optical communication ceramic ferrule, characterized in that, The specific method for preparing the 5G optical communication ceramic ferrule is as follows: the powder material, a high molecular thermoplastic resin, a dispersing agent and a lubricant are put into a mixer at a temperature of 150-180℃ for mixing for 90-120 min, then pelletized into injection molding particles with a diameter of 2 mm and a length of 2 mm, and then put into a ceramic injection molding machine, and injected into a ferrule mold at a temperature of 150-180℃, a pressure of 50 MPa and a speed of 80-100 mm / s to obtain a ferrule blank, and finally, after debinding at 400-550℃ for 3-5 h, sintering at 1250-1350℃ for 10-15 h to obtain the 5G optical communication ceramic ferrule.

9. Use according to claim 8, characterized in that, The mass ratio of the powder material, the high molecular thermoplastic resin, the dispersing agent and the lubricant is 80-90:6-15:2-3:2-4; the high molecular thermoplastic resin is an acrylic resin; the lubricant is microcrystalline wax; and the dispersing agent is stearic acid or oleic acid.

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