Rubber sealing ring accessory for coffee pot

Abstract

The invention discloses a rubber sealing ring accessory for a coffee pot, and the rubber sealing ring accessory is prepared from the following components in parts by weight: 95 to 105 parts of raw silicone rubber, 38 to 43 parts of fumed silica, 5 to 8 parts of hydroxyl silicone oil, 1 to 3 parts of hyperbranched cross-linking agent, 0.1 to 0.14 part of Karst catalyst, 0.05 to 0.07 part of inhibitor and 1.0 to 1.2 parts of vulcanizing agent, the hyperbranched cross-linking agent and the vulcanizing agent are adopted for cross-linking the silicone rubber, a uniform three-dimensional cross-linked network can be formed, and the obtained rubber sealing ring has excellent aging resistance and mechanical performance.

Description

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a rubber sealing ring accessory for a coffee pot. Background Art

[0002] In the past few years, the global coffee market has shown a steady growth trend, which is mainly due to the increasing popularity of global coffee consumption culture and people's pursuit of high-quality coffee, which in turn has driven the growth of demand for coffee pots. With the continuous expansion of the domestic coffee consumption market, consumers' requirements for coffee quality are constantly improving. As an important tool for making coffee, the market demand for coffee pots is also increasing.

[0003] As one of the main accessories of coffee pots, rubber seals have various configurations. Among them, O-type seals are simple in overall structure and low in cost, and are widely used in various types of coffee pots or coffee machines. Silicone rubber has excellent chemical stability, weather resistance, electrical insulation, hydrophobic recovery and physiological inertness, and other high-value practical properties. However, due to the structural characteristics of the molecular chain of the rubber material itself and the influence of the high temperature of coffee during use, rubber seals are prone to aging. As time goes by, the aging degree of the rubber seal accumulates, resulting in a decrease in its elasticity and sealing performance.

[0004] The high temperature resistance of silicone rubber is closely related to the structure of the rubber molecular chain, the content of water and impurities, and the use environment. There are several ways to improve the high temperature resistance of silicone rubber: (1) Modify the polymer molecular structure, which can be divided into main chain modification and side chain modification; (2) Use a suitable cross-linking agent to improve the stability of the cross-linking bond; (3) Use high temperature resistant additives. The stability of the cross-linking bond between silicone rubber molecular chains has a great influence on the high temperature resistance of the product. The better the thermal stability of the cross-linking bond, the better the high temperature resistance of the rubber, thereby improving the aging resistance of the rubber seal. Summary of the invention

[0005] Based on this, the present invention provides a rubber sealing ring accessory for a coffee pot and a preparation method thereof. The silicone rubber is cross-linked with a hyperbranched cross-linking agent and a vulcanizing agent to form a uniform three-dimensional cross-linked network. The obtained rubber sealing ring has excellent anti-aging ability and mechanical properties.

[0006] The technical solution for achieving the purpose of the present invention is as follows:

[0007] A rubber sealing ring accessory for a coffee pot, the rubber sealing ring accessory, comprising the following components by weight: 95-105 parts of silicone rubber raw rubber, 38-43 parts of fumed silica, 5-8 parts of hydroxy silicone oil, 1-3 parts of hyperbranched crosslinking agent, 0.1-0.14 parts of Custer catalyst, 0.05-0.07 parts of inhibitor, and 1.0-1.2 parts of vulcanizing agent; the preparation method of the hyperbranched crosslinking agent is as follows:

[0008] S1. Add 1 eq of N,N'-methylenebisacrylamide to a reaction kettle containing methanol and water, stir at a temperature of 30 to 35°C until completely dissolved, then add 1.05 to 1.1 eq of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, and stir at 55 to 65°C for 22 to 24 hours;

[0009] S2. 2.0 to 2.1 eq of the modified methacrylate monomer is added to the mixed solution of step S1, stirred at 55 to 65 ° C for 22 to 24 h, and then the solution is removed by rotary evaporation. The solid is washed with deionized water and a mixed solution of petroleum ether and ethyl acetate to obtain a hyperbranched crosslinker;

[0010] The modified methacrylate monomer has the following molecular structure:

[0011]

[0012] Preferably, the silicone rubber raw rubber is methyl vinyl silicone rubber, and the vinyl content of the methyl vinyl silicone rubber is 0.03% to 0.24%.

[0013] Preferably, the inhibitor is one or more of 1-ethynylcyclohexanol, diallyl maleate and diethyl fumarate; and the vulcanizing agent is 2,5-dimethyl-2,5-tert-butyl peroxide hexane.

[0014] More preferably, the inhibitor is 1-ethynylcyclohexanol.

[0015] Preferably, the volume ratio of methanol to water in step S1 is 3:1-2.

[0016] Preferably, the preparation method of the modified methacrylate monomer is as follows:

[0017] 1) 1 eq of hexamethylcyclotrisiloxane was placed in a round-bottom flask, and under an argon atmosphere, 1 eq of dimethyl monochlorosilane and 20-30 eq of acetonitrile were added, and then a catalytic amount of dimethylformamide was added. After the mixture was stirred at room temperature for 60-70 hours, the reaction mixture was directly purified by vacuum distillation, and a fraction of 39-41° C. was collected at 1.1 mbar;

[0018] 2) Under a nitrogen atmosphere, at a temperature of 0 to 5° C., 2.0 to 2.5 eq of hydroxyethyl methacrylate and 2.5 to 3.0 eq of triethylamine were dissolved in dry dichloromethane and added to a reaction kettle, 1 eq of the fraction obtained in step 1) was dispersed in dry dichloromethane and slowly added dropwise to the reaction kettle, stirred for 20 to 30 min, heated to room temperature and stirred for 4 to 5 h, the solvent was removed, and the modified methacrylate monomer was purified by column chromatography to obtain.

[0019] More preferably, the dimethylformamide in step 1) is 1% of the mass of hexamethylcyclotrisiloxane.

[0020] Preferably, the preparation method of the rubber sealing ring accessory is as follows:

[0021] (1) Pour fumed silica into a vacuum kneader, then slowly add silicone rubber raw rubber, close the vacuum valve and exhaust valve of the kneader and then mix, add hydroxy silicone oil, hyperbranched crosslinking agent and inhibitor in batches during the mixing process, after the filler and the raw rubber are evenly mixed, heat the kneader to 150° C. and mix for 2 h, then vacuum knead at 120° C. and mix for 1 h, and cool to room temperature to obtain a silicone rubber masterbatch;

[0022] (2) Adding Custer catalyst and vulcanizing agent to the masterbatch by a double-roll mill, mixing evenly to form a sheet, which is then placed in a mold and vulcanized for 18 to 20 minutes in a flat vulcanizer at 165°C and 8MPa. After cleaning, the rubber sealing ring accessories are obtained.

[0023] Beneficial Effects

[0024] The present invention has the following beneficial effects: providing a rubber sealing ring with excellent anti-aging ability and mechanical properties, cross-linking the silicone rubber by a hyperbranched cross-linking agent and a vulcanizing agent, and being able to form a uniform three-dimensional cross-linking network; the amide groups in the molecules can be used as antioxidant stabilizers, the multiple cross-linking structures limit the penetration of oxygen, and provide long-term stability of mechanical strength, and the complex spatial structure slows down the diffusion rate of water molecules; the diversity of cross-linking points provides structural redundancy, and the overall performance can be maintained even if it is partially degraded. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The steps for synthesizing the modified methacrylate monomer of the present invention;

[0026] Figure 2 The following are the steps and schematic diagram for synthesizing the hyperbranched crosslinking agent of the present invention;

[0027] Figure 3 The figure is a comparison diagram of the hydrogen NMR spectra of the methacrylate monomer modified by the present invention and the hyperbranched crosslinking agent.

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0030] The raw materials and equipment used in the embodiments and comparative examples are described as follows:

[0031] Vacuum kneading machine: Model SH-5, Jiangsu Rugao Shengteng Kneading Machinery Co., Ltd.;

[0032] Double-roll mixing mill: Model XSK1608, Dongfang Machinery, Huzhou, Zhejiang;

[0033] Flat vulcanizing press: Model XLB-D400×400, Dongfang Machinery, Huzhou, Zhejiang;

[0034] Methyl vinyl silicone rubber (MVQ110-0): vinyl content of 0.03-0.06%, purchased from Hesheng Silicon Industry Co., Ltd.;

[0035] Methyl vinyl silicone rubber (MVQ110-3): vinyl content of 0.19-0.24%, purchased from Hesheng Silicon Industry Co., Ltd.;

[0036] Fumed silica: brand HP-200, purchased from Jiangxi Hongbai New Materials Co., Ltd.;

[0037] Hydroxyl silicone oil: hydroxyl content 8wt.%, purchased from Wuhan Jiyesheng Chemical Co., Ltd.;

[0038] Hydrogenated silicone oil: hydrogen content 1.2wt.%, Shenzhen Senri Silicone Materials Co., Ltd.;

[0039] Custer catalyst: Pt content 2%, purchased from Shanghai MacLean Biochemical Technology;

[0040] Inhibitor: 1-ethynylcyclohexanol, No. E809391, purchased from Shanghai MacLean Biochemical Technology;

[0041] Curing agent: 2,5-dimethyl-2,5-bis-(tert-butylperoxy)hexane, No. T819468, purchased from Shanghai MacLean Biochemical Technology;

[0042] N,N'-Methylenebisacrylamide: No. 1084860, purchased from Shanghai Haohong Biopharmaceutical Technology Co., Ltd.;

[0043] 1,3-Bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane: Beijing Huawei Ruike Chemical Technology Co., Ltd.;

[0044] Hexamethylcyclotrisiloxane: No. H830620, purchased from Shanghai MacLean Biochemical Technology;

[0045] Dimethyl monochlorosilane: No. M01395, purchased from Shanghai Myrrel Biochemical Technology Co., Ltd.;

[0046] Hydroxyethyl methacrylate: No. H810855, purchased from Shanghai MacLean Biochemical Technology;

[0047] Modified methacrylate monomer (homemade):

[0048] 1) 1 eq of hexamethylcyclotrisiloxane was placed in a round-bottom flask, and under an argon atmosphere, 1 eq of dimethyl monochlorosilane and 30 eq of acetonitrile were added, and then a catalytic amount of dimethylformamide was added. After the mixture was stirred at room temperature for 65 h, the reaction mixture was directly purified by vacuum distillation, and the fraction at 39-41° C. was collected at 1.1 mbar;

[0049] 2) Under a nitrogen atmosphere, at a temperature of 0 to 5° C., 2.5 eq of hydroxyethyl methacrylate and 3.0 eq of triethylamine were dissolved in dry dichloromethane and added to a reaction kettle, 1 eq of the fraction obtained in step 1) was dissolved in dry dichloromethane and slowly added dropwise to the reaction kettle, stirred for 30 min, heated to room temperature and stirred for 5 h, the solvent was removed, and the modified methacrylate monomer was purified by column chromatography to obtain.

[0050] Hyperbranched crosslinker (homemade)

[0051] S1. Add 1 eq of N,N'-methylenebisacrylamide to a reaction kettle containing methanol and water, stir at 35°C until completely dissolved, then add 1.1 eq of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, and stir at 60°C for 24 h;

[0052] S2. Add 2.05 eq of the modified methacrylate monomer to the mixed solution of step S1, stir at 60°C for 24 h, and then remove the solvent by rotary evaporation. The obtained solid is washed with deionized water and a mixed solution of petroleum ether and ethyl acetate in turn to obtain a hyperbranched crosslinker.

[0053] like Figure 3 From the comparison of the H NMR spectra of the modified methacrylate monomer and the hyperbranched crosslinker, it can be seen that the double bond peaks with chemical shifts of 5.5ppm and 6.0ppm disappeared after polymerization, which can be inferred that Michael addition occurred between the amino group and the double bond.

[0054] A rubber sealing ring accessory for a coffee pot, the preparation method is as follows:

[0055] (1) Pour fumed silica into a vacuum kneader, then slowly add MVQ110-0 and MVQ110-3, close the vacuum valve and exhaust valve of the kneader and mix, add hydroxy silicone oil, hyperbranched crosslinking agent and inhibitor in batches during the mixing process, after the filler and the raw rubber are evenly mixed, heat the kneader to 150° C. and mix for 2 h, then vacuum knead at 120° C. for 1 h, and cool to room temperature to obtain a silicone rubber masterbatch;

[0056] (2) Adding Custer catalyst and vulcanizing agent to the masterbatch by a double-roll mill, mixing evenly to form a sheet, which is then placed in a mold and vulcanized for 18 to 20 minutes in a flat vulcanizer at 165°C and 8MPa. After cleaning, the rubber sealing ring accessories are obtained.

[0057] Table 1 Rubber sealing ring accessories formula (parts)

[0058]

[0059] The following is the test method of the performance parameters involved in the present invention:

[0060] (1) Determination of cross-link density: The cross-link density was measured by the equilibrium swelling method using toluene as solvent; the vulcanized rubber was cut into 10 mm × 10 mm × 2 mm specimens and placed in a forced air oven at 80 ° C for 24 h to remove moisture and other volatile components in the sample. After the specimens were cooled to room temperature, the original mass of the specimens (m0) was accurately measured, and then the specimens were immersed in toluene at room temperature, and the mass of the specimens was continuously recorded until the specimens reached swelling equilibrium and the mass of the swollen specimens (m s ), volume fraction of rubber after swelling Calculated according to formula 1: Crosslink density (V e ) is calculated according to Formula 2;

[0061]

[0062] In formula 1, m0 is the original mass of the spline; m s is the mass of the spline after swelling; ρ is the density of the spline; ρ t is the density of toluene; in formula 2, V0 is the molar volume of toluene, V0 = 106.54 × 10 -3 , χ is the interaction parameter between toluene and rubber,

[0063] (2) Mechanical properties test: Tensile and tear properties were tested on a tensile testing machine in accordance with ISO 37-2005 and ISO 34-1-2004 standards. Shore A hardness was tested on a Shore rubber hardness tester in accordance with ISO 7619-1-2004 standards.

[0064] (3) Hydrophobic recovery test: The rubber was cut into discs with a diameter of 25 mm and a thickness of 2 mm and placed in a plasma instrument for 30 seconds to transform the rubber surface into a completely hydrophilic surface. Then, the disc was placed in an environment of 25°C and a contact angle meter was used to continuously record the change in the water contact angle of the rubber surface until the hydrophobicity of the surface no longer changed significantly.

[0065] (5) Compression set rate: A cylindrical rubber specimen with a height of about 10 cm (±0.3) mm was prepared in accordance with GB / T 1683-2018 “Determination of compression set of vulcanized rubber at constant deformation”. The rubber sample was installed in a fixture with a compression amount of 30%. The test conditions were temperature 90°C and humidity 90%. After each selected interval, the rubber sample was taken out and the load was unloaded. After standing at room temperature for one hour, the height was measured and the measurement data was recorded.

[0066] Table 2 Crosslinking density, mechanical properties and hydrophobic recovery ability of rubber sealing ring accessories

[0067]

[0068] Table 3 Compression permanent deformation rate of rubber sealing ring accessories

[0069]

[0070]

[0071] It can be seen from the data of Examples 3 to 7 in Table 2 that as the content of the hyperbranched crosslinking agent increases, the crosslinking density, hardness, and 100% tensile strength of the obtained material gradually increase; the tensile strength, elongation at break, and tear strength first increase and then decrease; the hydrophobic recovery changes slightly at first, and suddenly decreases as it increases. As the crosslinking density increases, the migration ability of the small molecule siloxane or polysiloxane molecular chain inside the silicone rubber gradually decreases, resulting in a decrease in the ability of hydrophobic recovery. It can be seen from the data of Comparative Examples 2 and 3 that without adding the hyperbranched crosslinking agent prepared by the present invention or replacing it with a linear hydrogenated silicone oil, the prepared rubber properties, except for hydrophobic recovery and elongation at break, are not as good as the rubber prepared by Examples 3 to 7; it can be seen from the data of Comparative Example 1 that excessive addition of the hyperbranched crosslinking agent of the present invention will result in excessive hardness, which is not conducive to use as a sealing accessory.

[0072] Since the rubber sealing ring accessories of the coffee pot are in a hot and humid environment for a long time, we mainly tested the compression permanent deformation rate in the hot and humid environment;

[0073] From the data in Table 3, it can be seen that under the test environment of temperature 90°C and humidity 90%, it can be seen that with the increase of crosslinking density, the compression permanent deformation rate gradually decreases, but the improvement effect is becoming less and less obvious. Among them, the mechanical properties and hydrophobic recovery ability of Example 5 are relatively excellent, and the compression permanent deformation rate only changes by 0.18% in 192h, which is suitable for the use environment of rubber sealing ring accessories of coffee pots.

[0074] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A rubber sealing ring accessory for a coffee pot, characterized in that: The rubber sealing ring accessory comprises the following components by weight: 95-105 parts of silicone rubber, 38-43 parts of fumed silica, 5-8 parts of hydroxy silicone oil, 1-3 parts of hyperbranched crosslinking agent, 0.1-0.14 parts of Custer catalyst, 0.05-0.07 parts of inhibitor, and 1.0-1.2 parts of vulcanizing agent; the preparation method of the hyperbranched crosslinking agent is as follows: S1. Add 1 eq of N,N'-methylenebisacrylamide to a reaction kettle containing methanol and water, stir at a temperature of 30 to 35°C until completely dissolved, then add 1.05 to 1.1 eq of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, and stir at 55 to 65°C for 22 to 24 hours; S2. 2.0 to 2.1 eq of the modified methacrylate monomer is added to the mixed solution of step S1, stirred at 55 to 65 ° C for 22 to 24 h, and then the solution is removed by rotary evaporation. The solid is washed with deionized water and a mixed solution of petroleum ether and ethyl acetate to obtain a hyperbranched crosslinker; The modified methacrylate monomer has the following molecular structure:

2. A rubber sealing ring accessory for a coffee pot as claimed in claim 1, characterized in that: The silicone rubber raw rubber is methyl vinyl silicone rubber, and the vinyl content of the methyl vinyl silicone rubber is 0.03% to 0.24%.

3. A rubber sealing ring accessory for a coffee pot as claimed in claim 1, characterized in that: The inhibitor is one or more of 1-ethynylcyclohexanol, diallyl maleate and diethyl fumarate; and the vulcanizing agent is 2,5-dimethyl-2,5-tert-butyl peroxide hexane.

4. A rubber sealing ring accessory for a coffee pot as claimed in claim 1, characterized in that: The volume ratio of methanol to water in step S1 is 3:1 to 2:1; the volume ratio of the mixed solution of petroleum ether and ethyl acetate in step S2 is 10:1 to 5:

1.

5. A rubber sealing ring accessory for a coffee pot as claimed in claim 1, characterized in that: The preparation method of the modified methacrylate monomer is as follows: 1) 1 eq of hexamethylcyclotrisiloxane was placed in a round-bottom flask, and under an argon atmosphere, 1 eq of dimethyl monochlorosilane and 20-30 eq of acetonitrile were added, and then a catalytic amount of dimethylformamide was added. After the mixture was stirred at room temperature for 60-70 hours, the reaction mixture was directly purified by vacuum distillation, and a fraction of 39-41° C. was collected at 1.1 mbar; 2) Under a nitrogen atmosphere, at a temperature of 0 to 5° C., 2.0 to 2.5 eq of hydroxyethyl methacrylate and 2.5 to 3.0 eq of triethylamine were dissolved in dry dichloromethane and added to a reaction kettle, 1 eq of the fraction obtained in step 1) was dissolved in dry dichloromethane and slowly added dropwise to the reaction kettle, stirred for 20 to 30 min, heated to room temperature and stirred for 4 to 5 h, the solvent was removed, and the modified methacrylate monomer was purified by column chromatography to obtain.

6. A rubber sealing ring accessory for a coffee pot as claimed in claim 1, characterized in that: The preparation method of the rubber sealing ring accessory is as follows: (1) Pour fumed silica into a vacuum kneader, then slowly add silicone rubber raw rubber, close the vacuum valve and exhaust valve of the kneader and then mix, add hydroxy silicone oil, hyperbranched crosslinking agent and inhibitor in batches during the mixing process, after the filler and the raw rubber are evenly mixed, heat the kneader to 150° C. and mix for 2 h, then vacuum knead at 120° C. and mix for 1 h, and cool to room temperature to obtain a silicone rubber masterbatch; (2) Adding Custer catalyst and vulcanizing agent to the masterbatch by a double-roll mill, mixing evenly to form a sheet, which is then placed in a mold and vulcanized for 18 to 20 minutes in a flat vulcanizer at 165°C and 8MPa. After cleaning, the rubber sealing ring accessories are obtained.

Images