Molecular sieve for refrigerator molecular sieve drying filter and preparation method thereof

Abstract

The present invention discloses a molecular sieve for a refrigerator molecular sieve drying filter, and relates to the technical field of molecular sieves. The molecular sieve comprises: 100-120 parts of molecular sieve raw powder, 5-25 parts of a binder, 1-3 parts of a surface modifier, 5-20 parts of a structural enhancement powder, and 3-8 parts of a lubricant; the binder comprises clay, a silicone acrylic emulsion, and a nano-alumina sol in a weight ratio of (14-17):(2-4):(1-2). The molecular sieve is prepared by: uniformly mixing the molecular sieve raw powder, the binder, the surface modifier, the structural enhancement powder, and the lubricant to obtain a ready-to-use material; and molding, drying, and calcining the ready-to-use material to obtain the molecular sieve. The molecular sieve of the present application has a static water adsorption rate of 16-21%, a strength of 70-100N, and an abrasion rate of 0.15-0.85%. It can be used for drying and dehydrating a variety of refrigerants. It has high physical properties, strong water absorption capacity, high strength, and low abrasion rate. It can effectively absorb moisture in the refrigerant and prevent corrosion and freezing of the refrigeration system caused by refrigerant freezing.

Description

Technical Field

[0001] The present invention relates to the technical field of molecular sieves, and in particular to a molecular sieve for use in refrigerator molecular sieve drying filters. Furthermore, the present application also relates to a method for preparing the molecular sieve for use in refrigerator molecular sieve drying filters. Background Art

[0002] Molecular sieves are a type of adsorbent or film-like substance with uniform micropores whose pore size is comparable to the size of general molecules. They can be used to screen fluid molecules of different sizes and are widely used in fields such as air conditioners and refrigerators.

[0003] In the prior art, molecular sieve filters in refrigerators are used to filter moisture from the refrigerant, thereby drying the refrigerant. Therefore, the molecular sieve used in refrigerator molecular sieve filters must possess excellent drying properties. However, molecular sieves operate normally within refrigerator molecular sieve filters at a certain flow rate and pressure. Typical molecular sieves are not strong enough and have a high wear rate. This often leads to the molecular sieve pulverizing, causing quality issues such as blockage of refrigeration lines, reduced cooling efficiency, or even refrigeration failure, significantly shortening the service life of the refrigerator molecular sieve filter. Summary of the Invention

[0004] In order to reduce the pulverization of molecular sieves used in molecular sieve drying filters for refrigerators, the present application provides a molecular sieve used in molecular sieve drying filters for refrigerators.

[0005] In a first aspect, the present application provides a molecular sieve for a molecular sieve drying filter in a refrigerator, which adopts the following technical solution:

[0006] A molecular sieve for a molecular sieve drying filter in a refrigerator comprises the following components in parts by weight: 100-120 parts of molecular sieve raw powder, 5-25 parts of a binder, 1-3 parts of a surface modifier, 5-20 parts of a structure-reinforced powder, and 3-8 parts of a lubricant; the binder comprises clay, a silicone-acrylic emulsion, and a nano-alumina sol in a weight ratio of (14-17):(2-4):(1-2).

[0007] By adopting the above technical solution, the surface modifier can modify the surface of the molecular sieve raw powder and the structure-enhanced powder, so that the molecular sieve raw powder and the structure-enhanced powder can be better compatible with other components. Clay is a sticky soil with good plasticity. Clay is any one or a mixture of two of kaolin and attapulgite. Kaolin is clay and clay rock mainly composed of kaolinite clay minerals. It has good plasticity and a fine texture. It can effectively improve the strength of the finished molecular sieve and reduce the wear rate of the finished molecular sieve. Attapulgite is a hydrated magnesium-aluminum silicate clay mineral with a chain-layered structure. It has a fine texture, good plasticity, and strong water absorption. It can not only reduce the wear rate of the finished molecular sieve, but also improve the hygroscopic properties of the finished molecular sieve. It can effectively absorb moisture in the refrigerant to avoid corrosion and freezing of the refrigeration system caused by freezing of the refrigerant.

[0008] Nano-alumina sol contains nano-scale alumina particles, and silicone-acrylic emulsion has high adhesion and high flexibility. Using clay, silicone-acrylic emulsion, and nano-alumina sol as a binder helps improve the bonding effect and density of the finished molecular sieve. The structural reinforcement powder can increase the compressive strength of the finished molecular sieve. Therefore, the combined action of the binder and the structural reinforcement powder helps to improve the hardness of the finished molecular sieve. This application also adds a lubricant to reduce the friction coefficient of the finished molecular sieve, thereby reducing the wear rate of the finished molecular sieve. Therefore, the synergistic action of the above-mentioned components can improve the strength of the finished molecular sieve while reducing the wear rate of the finished molecular sieve, thereby reducing the pulverization of the molecular sieve, resulting in a specialized molecular sieve that is more suitable for refrigerator molecular sieve drying filters.

[0009] In a specific embodiment, the structure-reinforcing powder includes at least one of lime powder, alumina powder or silicon carbide powder.

[0010] By adopting the above technical solution, the gray calcium powder not only enhances the strength of the finished molecular sieve, but also improves the bonding effect and density of the finished molecular sieve after mixing with the binder. Furthermore, the gray calcium powder is fine and smooth and has good moisture absorption, which helps reduce the wear rate of the finished molecular sieve and improve its moisture absorption effect. This further reduces molecular sieve pulverization and refrigerant freezing, thereby reducing corrosion and freezing blockage in refrigerator refrigeration systems. Alumina powder and silicon carbide powder both have high hardness, which can improve the strength of the finished molecular sieve and reduce molecular sieve pulverization and breakage.

[0011] In a specific embodiment, the surface modifier includes a silane coupling agent.

[0012] By adopting the above technical solution, the silane coupling agent can modify the surface of the molecular sieve raw powder and the structure-enhanced powder, promote the chemical bonding between the molecular sieve raw powder and the structure-enhanced powder and the organic components, and thus help improve the density of the molecular sieve finished product and enhance the strength of the molecular sieve finished product.

[0013] In a specific embodiment, the surface modifier further comprises polymethyl methacrylate and ethylene dichloride.

[0014] By adopting the above technical solution, polymethyl methacrylate is dissolved in ethylene dichloride, and after the surface of the molecular sieve raw powder and the structure-enhanced powder is modified, a very tough structure can be formed between the particles, which helps to reduce particle shedding and thus reduce the pulverization of the molecular sieve finished product.

[0015] In one specific embodiment, the lubricant includes fluorinated graphite.

[0016] By adopting the above technical solution, graphite fluoride has a low friction coefficient, a long friction life, and excellent thermal and chemical stability. It can maintain good lubrication properties in almost all atmospheres and is particularly suitable for use under harsh conditions such as high temperature, high pressure, high speed, high load, and corrosive media. Therefore, the use of graphite fluoride can improve the adaptability of the finished molecular sieve in refrigerator molecular sieve drying filters and reduce the pulverization of the finished molecular sieve.

[0017] In a specific embodiment, the static water adsorption rate of the molecular sieve is 16-21%, the strength of the molecular sieve is 70-100N, and the attrition rate of the molecular sieve is 0.15-0.85%.

[0018] By adopting the above technical solution and the above raw material ratio, a molecular sieve within the above performance index range can be prepared. Compared with ordinary molecular sieves, the molecular sieve prepared in the present application has a higher static water adsorption rate, greater strength, and lower abrasion rate. Therefore, the molecular sieve of the present application is not easy to pulverize, and can better adsorb moisture in the refrigerant, thereby reducing corrosion or freezing of the refrigerator's refrigeration system.

[0019] In a specific embodiment, the molecular sieve raw powder is 3A molecular sieve raw powder with a potassium exchange rate of 18%-45%.

[0020] By adopting the above technical solution, under the above raw material ratio, and selecting the molecular sieve raw powder with the above potassium exchange rate, the prepared molecular sieve finished product is suitable for the dehydration and drying of most refrigerants such as R-401A, R404a, R404b, and has a wider range of applications.

[0021] In a second aspect, the present application provides a method for preparing a molecular sieve for a molecular sieve drying filter in a refrigerator, using the following technical solution:

[0022] A method for preparing a molecular sieve for a molecular sieve drying filter in a refrigerator comprises the following steps:

[0023] Preparation of materials: molecular sieve raw powder, binder, surface modifier, structure enhancement powder and lubricant are mixed evenly to obtain the standby material;

[0024] Finished product: The spare materials are formed, dried and calcined to obtain molecular sieve.

[0025] In a specific embodiment, in the step of preparing the materials, the molecular sieve raw powder, the surface modifier and the structure-enhancing powder are uniformly mixed in advance to obtain the modified material; and then the modified material, the binder and the lubricant are uniformly mixed to obtain the standby material.

[0026] By adopting the above technical solution, the preparation method of the present application can improve the compatibility between the molecular sieve raw powder and the structure-enhancing powder and other organic components, help to form chemical bonds, improve the density and strength of the molecular sieve finished product, reduce the wear rate of the molecular sieve finished product, and thus reduce the pulverization problem of the molecular sieve finished product.

[0027] In a specific embodiment, in the product manufacturing step, the prepared material is formed, dried and calcined to obtain a crude product, and the surface of the crude product is polished to obtain the molecular sieve.

[0028] By adopting the above technical solution, the surface of the coarse product is polished, which helps to further reduce the wear rate of the finished molecular sieve product and reduce the powdering phenomenon of the finished molecular sieve product.

[0029] In summary, this application includes at least one of the following beneficial technical effects:

[0030] 1. The molecular sieve of this application can be used for drying and dehydrating a variety of refrigerants. It has high physical properties, strong water absorption capacity, high strength, and low wear rate. It can effectively absorb moisture in the refrigerant and prevent corrosion and freezing of the refrigeration system caused by refrigerant freezing.

[0031] 2. This application improves the strength of the molecular sieve product and reduces the wear rate of the molecular sieve product through the synergistic effect of various components such as molecular sieve raw powder, binder, surface modifier, structure-enhancing powder and lubricant;

[0032] 3. The preparation method of the present application can further reduce the pulverization of molecular sieves. DETAILED DESCRIPTION

[0033] The inventors found that the molecular sieves used in the molecular sieve drying filters of old refrigerators on the market were of average quality and often had the following quality problems:

[0034] 1. Due to the insufficient strength of the molecular sieve, the molecular sieve often becomes powdered, which will cause the refrigeration pipeline to be blocked and the refrigeration equipment to fail to refrigerate;

[0035] 2. The molecular sieve abrasion rate data is too high. When the refrigerator molecular sieve filter drier is working normally, there is a certain flow rate and pressure. If the abrasion rate data is too high, it will gradually cause the molecular sieve to pulverize, greatly shortening the service life of the entire refrigerator molecular sieve filter drier, causing the refrigerator refrigeration system to have a reduced cooling effect and other quality problems;

[0036] 3. Due to the limited water absorption capacity of molecular sieve, the refrigerant often contains too much water, the refrigerant freezes, or the refrigeration system is corroded and blocked.

[0037] Through research, the inventors have invented a molecular sieve for refrigerator molecular sieve drying filters. This molecular sieve can be used for drying and dehydrating a variety of refrigerants. It has high physical properties, strong water absorption capacity, high strength, and low wear rate. It can effectively absorb moisture from the refrigerant, avoiding corrosion and freezing of the refrigeration system caused by refrigerant freezing. It can also greatly extend the service life of the molecular sieve drying filter and reduce the quality risk of the refrigerator refrigeration system. It is suitable for the dehydration and drying of most refrigerants such as R-401A, R404a, and R404b.

[0038] The present application is further described in detail below with reference to the embodiments.

[0039] Example

[0040] Example 1

[0041] This embodiment provides a binder, which uses the following components in a weight ratio: kaolin: ZK-885 silicone acrylic emulsion: JR14W nano alumina sol = 15.5:3:1.5.

[0042] Add kaolin, silicone-acrylic emulsion and nano-alumina sol into a reaction kettle and stir until uniform to obtain a binder.

[0043] This embodiment provides a molecular sieve, using the following components: 110 kg of 3A molecular sieve raw powder with a potassium exchange rate of (18±2)%, 15 kg of binder, 2 kg of KH560 silane coupling agent, 12 kg of gray calcium powder and 6 kg of graphite fluoride.

[0044] The preparation method of molecular sieve is as follows:

[0045] According to the above ratio, the molecular sieve raw powder, the binder, the silane coupling agent, the gray calcium powder and the fluorinated graphite are mixed and stirred until uniform to obtain the standby material.

[0046] The prepared material is then rolled into balls, dried at 100°C for 15 hours, and the dried balls are turned into a calcining furnace, calcined at 600°C for 5 hours, and then cooled to obtain a molecular sieve.

[0047] Example 2

[0048] The only difference between this embodiment and embodiment 1 is that the molecular sieve uses the following components: 100 kg of 3A molecular sieve raw powder with a potassium exchange rate of (18±2)%, 5 kg of binder, 1 kg of KH560 silane coupling agent, 5 kg of gray calcium powder and 3 kg of graphite fluoride.

[0049] Example 3

[0050] The only difference between this embodiment and embodiment 1 is that the molecular sieve uses the following components: 105 kg of 3A molecular sieve raw powder with a potassium exchange rate of (18±2)%, 10 kg of binder, 1.5 kg of KH560 silane coupling agent, 8 kg of gray calcium powder and 5 kg of graphite fluoride.

[0051] Example 4

[0052] The only difference between this embodiment and embodiment 1 is that the molecular sieve uses the following components: 115 kg of 3A molecular sieve raw powder with a potassium exchange rate of (18±2)%, 20 kg of binder, 2.5 kg of KH560 silane coupling agent, 16 kg of gray calcium powder and 7 kg of graphite fluoride.

[0053] Example 5

[0054] The only difference between this embodiment and embodiment 1 is that the molecular sieve uses the following components: 120 kg of 3A molecular sieve raw powder with a potassium exchange rate of (18±2)%, 25 kg of binder, 3 kg of KH560 silane coupling agent, 20 kg of gray calcium powder and 8 kg of graphite fluoride.

[0055] Example 6

[0056] The only difference between this embodiment and embodiment 1 is that the binder has the following weight ratio of components: kaolin: ZK-885 silicone acrylic emulsion: JR14W nano alumina sol = 7:2:1.

[0057] Example 7

[0058] The only difference between this embodiment and embodiment 1 is that the binder has the following weight ratio of components: kaolin: ZK-885 silicone acrylic emulsion: JR14W nano alumina sol = 17:2:1.

[0059] Example 8

[0060] The only difference between this embodiment and embodiment 1 is that the 3A molecular sieve raw powder with a potassium exchange rate of (18±2)% is replaced by an equal amount of 3A molecular sieve raw powder with a potassium exchange rate of (32±2)%.

[0061] Example 9

[0062] The only difference between this embodiment and embodiment 1 is that the 3A molecular sieve raw powder with a potassium exchange rate of (18±2)% is replaced by an equal amount of 3A molecular sieve raw powder with a potassium exchange rate of (45±2)%.

[0063] Example 10

[0064] The only difference between this embodiment and embodiment 1 is that the 3A molecular sieve raw powder with a potassium exchange rate of (18±2)% is replaced by an equal amount of 5A molecular sieve raw powder with a potassium exchange rate of (18±2)%.

[0065] Example 11

[0066] The only difference between this embodiment and embodiment 1 is that kaolin is replaced by an equal amount of attapulgite.

[0067] Example 12

[0068] The only difference between this embodiment and embodiment 1 is that the kaolin is replaced by an equal amount of a mixture of kaolin and attapulgite in a weight ratio of 1:1.

[0069] The preparation method of molecular sieve is as follows:

[0070] According to the above ratio, kaolin and attapulgite are first mixed uniformly in a weight ratio of 1:1 to obtain a mixture.

[0071] Then, the molecular sieve raw powder, the binder, the silane coupling agent, the mixture and the graphite fluoride are mixed and stirred until uniform to obtain the standby material.

[0072] The prepared material is then rolled into balls, dried at 100°C for 15 hours, and the dried balls are turned into a calcining furnace, calcined at 600°C for 5 hours, and then cooled to obtain the molecular sieve.

[0073] Example 13

[0074] The only difference between this embodiment and embodiment 1 is that the lime powder is replaced by an equal amount of alumina powder.

[0075] Example 14

[0076] The only difference between this embodiment and embodiment 1 is that the limestone powder is replaced by an equal amount of silicon carbide powder.

[0077] Example 15

[0078] The only difference between this embodiment and embodiment 1 is that the molecular sieve uses the following components: 110 kg of 3A molecular sieve raw powder with a potassium exchange rate of (18±2)%, 15 kg of binder, 1 kg of KH560 type silane coupling agent, 12 kg of gray calcium powder, 6 kg of fluorinated graphite, 0.5 kg of polymethyl methacrylate and 0.5 kg of ethylene dichloride.

[0079] The preparation method of molecular sieve is as follows:

[0080] According to the above ratio, polymethyl methacrylate is dissolved in dichloroethane, and then evenly mixed with a silane coupling agent to obtain a surface modifier.

[0081] The molecular sieve raw powder, the binder, the surface modifier, the gray calcium powder and the fluorinated graphite are mixed and stirred until uniform to obtain the standby material.

[0082] The prepared material is then rolled into balls, dried at 100°C for 15 hours, and the dried balls are turned into a calcining furnace, calcined at 600°C for 5 hours, and then cooled to obtain a molecular sieve.

[0083] Example 16

[0084] The only difference between this embodiment and embodiment 1 is that the preparation method of the molecular sieve is as follows:

[0085] According to the above ratio, the molecular sieve raw powder, silane coupling agent and gray calcium powder are mixed and stirred until uniform to obtain a modified material, and then the modified material, binder and fluorinated graphite are stirred until uniform to obtain a standby material.

[0086] The prepared material is then rolled into balls, dried at 100°C for 15 hours, and the dried balls are turned into a calcining furnace, calcined at 600°C for 5 hours, and then cooled to obtain the molecular sieve.

[0087] Example 17

[0088] The only difference between this embodiment and embodiment 1 is that an equal amount of MQ-22 lubricant is used to replace the fluorinated graphite.

[0089] Example 18

[0090] The only difference between this embodiment and embodiment 1 is that the preparation method of the molecular sieve is as follows:

[0091] According to the above ratio, the molecular sieve raw powder, silane coupling agent and gray calcium powder are mixed and stirred until uniform to obtain a modified material, and then the modified material, binder and fluorinated graphite are stirred until uniform to obtain a standby material.

[0092] The spare material is then rolled into balls and dried at 100°C for 15 hours. The dried balls are turned into a calciner, calcined at 600°C for 5 hours and then cooled to obtain a crude product. The surface of the crude product is polished with a polishing machine to obtain a molecular sieve.

[0093] Comparative Example

[0094] Comparative Example 1

[0095] The only difference between this comparative example and Example 1 is that the molecular sieve uses the following components: 90 kg of 3A molecular sieve raw powder with a potassium exchange rate of (18±2)%, 4 kg of binder, 0.5 kg of KH560 silane coupling agent, 4 kg of gray calcium powder and 2 kg of fluorinated graphite.

[0096] Comparative Example 2

[0097] The only difference between this comparative example and Example 1 is that the molecular sieve uses the following components: 130 kg of 3A molecular sieve raw powder with a potassium exchange rate of (18±2)%, 27 kg of binder, 4 kg of KH560 silane coupling agent, 22 kg of gray calcium powder and 10 kg of graphite fluoride.

[0098] Comparative Example 3

[0099] The only difference between this comparative example and Example 1 is that the molecular sieve does not contain KH560 silane coupling agent.

[0100] Comparative Example 4

[0101] The only difference between this comparative example and Example 1 is that the molecular sieve does not contain gray calcium powder.

[0102] Comparative Example 5

[0103] The only difference between this comparative example and Example 1 is that the molecular sieve does not contain fluorinated graphite.

[0104] Comparative Example 6

[0105] The only difference between this comparative example and Example 1 is that the binder is replaced by an equal amount of kaolin in the molecular sieve.

[0106] Performance testing

[0107] The molecular sieves (d = 1.6-2.5 mm) provided in Examples 1-18 and Comparative Examples 1-6 were subjected to performance testing in accordance with HG / T4220-2011 "Spherical Molecular Sieve Desiccant for Refrigerants," and the test results of strength, abrasion rate, and static water absorption (under constant temperature and humidity conditions of 50% humidity and 25 ± 2°C) are as follows.

[0108] Table 1

[0109]

[0110] Combining Example 1 with Comparative Examples 1-6 and Table 1, it can be seen that compared to Example 1, at least one of the strength, attrition rate, or static water absorption rate of the molecular sieves of Comparative Examples 1-6 is significantly worse. This indicates that the raw material ratio and process conditions of Example 1 are conducive to the preparation of molecular sieves with high strength, high water absorption rate, and low attrition rate. It also indicates that the lack of any one of the silane coupling agent, lime calcium powder, and fluorinated graphite will lead to worse performance of the molecular sieve. Moreover, compared to the use of kaolin, the use of the binder in Example 1 helps to improve the strength of the molecular sieve and reduce the attrition rate.

[0111] Combining Examples 1-5 and Table 1, it can be seen that the strength and static water absorption of the molecular sieves prepared in Examples 1-5 are relatively large, and the attrition rate is relatively small. This shows that within the range of raw material ratios and process conditions of Examples 1-18, it is helpful to prepare molecular sieves with high strength, high water absorption and low attrition rate.

[0112] Combining Examples 1, 6-7 and Table 1, it can be seen that the strength, static water absorption rate and abrasion rate of the molecular sieves prepared in Examples 6-7 change little, which shows that within the raw material ratio range of the above-mentioned binder, it is helpful to prepare a molecular sieve with high strength, high water absorption rate and low abrasion rate.

[0113] From Examples 1, 8-18 and Table 1, it can be seen that compared with Example 1, the strength and static water absorption of the molecular sieves prepared in Examples 8-18 are greater, and the abrasion rate is smaller. This shows that within the range of raw material ratios and process conditions of Examples 8-18, it is helpful to prepare molecular sieves with high strength, high water absorption and low abrasion rate. Under the process conditions of adding polymethyl methacrylate and dichloroethane, or polishing the molecular sieve, it is helpful to further improve the strength of the molecular sieve.

[0114] 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 non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A molecular sieve for a molecular sieve drying filter in a refrigerator, characterized in that: The invention comprises the following components in parts by weight: 100-120 parts of molecular sieve raw powder, 5-25 parts of a binder, 1-3 parts of a surface modifier, 5-20 parts of a structural reinforcement powder and 3-8 parts of a lubricant; the binder comprises clay, silicone-acrylic emulsion and nano-alumina sol in a weight ratio of (14-17):(2-4):(1-2); the static water adsorption rate of the molecular sieve is 16-21%, the strength of the molecular sieve is 70-100N, and the abrasion rate of the molecular sieve is 0.15-0.85%; and the surface modifier comprises a silane coupling agent.

2. The molecular sieve according to claim 1, characterized in that The structure-enhancing powder includes at least one of lime powder, alumina powder or silicon carbide powder.

3. The molecular sieve according to claim 1, characterized in that The surface modifier also includes polymethyl methacrylate and ethylene dichloride.

4. The molecular sieve according to claim 1, characterized in that The lubricant includes graphite fluoride.

5. The molecular sieve according to claim 1, characterized in that The molecular sieve raw powder is 3A molecular sieve raw powder with a potassium exchange rate of 18%-45%.

6. A method for preparing a molecular sieve according to any one of claims 1 to 5, characterized in that: The steps include: Preparation of materials: molecular sieve raw powder, binder, surface modifier, structure enhancement powder and lubricant are mixed evenly to obtain the standby material; Finished product: The spare materials are formed, dried and calcined to obtain molecular sieve.

7. The method according to claim 6, characterized in that In the material preparation step, the molecular sieve raw powder, the surface modifier and the structure enhancement powder are mixed uniformly in advance to obtain the modified material; Then, the modified material, the binder and the lubricant are mixed evenly to obtain the standby material.

8. The method according to claim 6, characterized in that In the product manufacturing step, the prepared material is formed, dried and calcined to obtain a crude product, and the surface of the crude product is polished to obtain the molecular sieve.

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