Single-component high-adhesion dealcoholized room-temperature vulcanized silicone sealant and preparation method thereof
By using terminal alkoxyaminopropyl polydimethylsiloxane as the base adhesive, along with specific fillers and catalysts, a one-component de-alcoholized room temperature vulcanizing silicone sealant was prepared, solving the bonding problems of fluoroplastics, fluororubbers, and fluorosilicone rubbers. It exhibits good bonding performance and stability, and achieves damping performance over a wide temperature range.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BAIMTEC MATERIAL CO LTD
- Filing Date
- 2023-06-21
- Publication Date
- 2026-07-24
Smart Images
Figure CN116790223B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer materials and their production technology, specifically to a single-component, high-adhesion, alcohol-free, room-temperature vulcanizing silicone sealant and its preparation method. Background Technology
[0002] One-component condensation-type room temperature vulcanizing silicone sealant (also known as one-component condensation-type room temperature vulcanizing silicone rubber) is the most common and widely used type of room temperature vulcanizing silicone sealant. Due to its ease of use, it is widely applied in construction, automotive, electronics, machinery, chemical, and light industry sectors. One-component condensation-type room temperature vulcanizing silicone sealant can be classified according to the crosslinking agent into ketoxime-free, alcohol-free, acetone-free, and amide-free types. Currently, the ketoxime-free and alcohol-free types are the main types of one-component room temperature vulcanizing silicone sealant used in engineering applications.
[0003] Adhesion is the most important concern for the application of one-component condensation-type room temperature vulcanizing silicone sealants. According to literature reports, existing one-component condensation-type room temperature vulcanizing silicone sealant solutions do not address the adhesion of fluoroplastics, fluororubbers, and fluorosilicone rubbers, which have high surface inertness and low surface energy. Theoretically, achieving good adhesion to these materials should also be difficult. This may be due to two reasons: firstly, silicone sealants themselves are debonding, resulting in varying adhesion to different substrates; secondly, fluoroplastics, fluororubbers, and fluorosilicone rubbers have extremely low surface activity, making them difficult to bond and technically challenging.
[0004] Existing literature and patents have extensively studied the bonding of polyolefin materials such as polypropylene, polyethylene, and polyvinyl chloride with single-component condensation-type room temperature vulcanizing silicone sealants, which are relatively difficult to bond. The main methods include: (1) using a combination of multiple silanes or condensation polymers, such as patent CN102277126A, which uses multiple aminosilanes to achieve good bonding of polypropylene; and using mercaptoalkoxysilanes and polyisocyanates as tackifiers to achieve good bonding of polypropylene (Elastic Sealants and Adhesives [M]. Huang Yingchang, Lü Zhengyun. Beijing). : Chemical Industry Press, 2003: 358); A condensation silane containing amino and epoxy groups is used as a tackifier to achieve good adhesion to polyvinyl chloride (Elastic sealant and adhesive [M]. Huang Yingchang, Lü Zhengyun. Beijing: Chemical Industry Press, 2003: 320); (2) The tackifier system of 1,3,5-tris(trimethoxysilylpropyl) polyisocyanate can achieve adhesion performance to a variety of substrates (Huang Wenrun, Preparation of single-component room temperature vulcanizing silicone rubber (X), Organosilicon Materials, 2004, 18(1): 35-39).
[0005] However, the methods described above are not suitable for bonding more difficult-to-bond fluoroplastics, fluororubbers, and fluorosilicone rubbers. Patent CN114958291A utilizes highly reactive γ-aminopropylbutanone oxime silanes to produce deketoxime-type and dealcohol-type room-temperature vulcanizing silicone sealants with good adhesion to fluoroplastics, fluororubbers, and fluorosilicone rubbers with high surface inertness and low surface energy. For the dealcohol-type room-temperature vulcanizing silicone sealant, hydroxyl-terminated polydimethylsiloxane is used as the raw material. However, this prior art cannot solve the problem of long-term storage stability (short product shelf life, at most 6 months). Summary of the Invention
[0006] The purpose of this invention is to provide a single-component, high-adhesion, de-alcoholized, room-temperature vulcanizing silicone sealant and its preparation method. Using terminal dialkoxyaminopropyl polydimethylsiloxane as the base adhesive, the prepared de-alcoholized silicone sealant exhibits good adhesion to substrates that are extremely difficult to bond, such as fluoroplastics, fluororubbers, and fluorosilicone rubbers. It also has excellent damping properties over a wide temperature range, as well as good mechanical properties and storage stability.
[0007] Therefore, in a first aspect, the present invention provides a single-component, alcohol-free, room-temperature vulcanizing silicone sealant, which comprises the following raw materials by weight: 100 parts of terminal dialkoxyaminopropyl polydimethylsiloxane, 100-200 parts of reinforcing filler, 3-8 parts of alkoxysilane crosslinking agent, and 0.1-1 parts of organotin catalyst; wherein the reinforcing filler comprises sheet filler.
[0008] In some embodiments, the sheet-like filler includes at least one of the following: mica powder, zirconium phosphate, and talc powder.
[0009] In some embodiments, the mass percentage of the sheet-like filler in the reinforcing filler is more than 50%; for example, it can be about 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, etc.
[0010] In some embodiments, in addition to the sheet-like filler, the reinforcing filler also includes at least one selected from the group consisting of zinc oxide, silica powder, quartz powder, calcium carbonate, and silica.
[0011] In some embodiments, the viscosity of the terminal alkoxyaminopropyl polydimethylsiloxane is 5000–80000 mPa·s; for example, about 5000 mPa·s, 6000 mPa·s, 10000 mPa·s, 20000 mPa·s, 30000 mPa·s, 40000 mPa·s, 50000 mPa·s, 60000 mPa·s, 70000 mPa·s, 80000 mPa·s, etc.
[0012] In some embodiments, the terminal dialkoxyaminopropyl polydimethylsiloxane comprises at least one selected from the group consisting of terminal dimethoxyaminopropyl polydimethylsiloxane and terminal diethoxyaminopropyl polydimethylsiloxane.
[0013] In some embodiments, the method for preparing the terminal dialkoxyaminopropyl polydimethylsiloxane includes: reacting the terminal hydroxyl polydimethylsiloxane with aminopropyltrialkoxysilane in the presence of an alkaline gel catalyst to obtain the terminal dialkoxyaminopropyl polydimethylsiloxane; wherein the alkaline gel catalyst is prepared by reacting tetramethylammonium hydroxide with dimethylcyclotetrasiloxane.
[0014] In some embodiments, 100 parts by weight of hydroxyl-terminated polydimethylsiloxane are reacted with 2 to 5 parts by weight of aminopropyltrialkoxysilane.
[0015] In some embodiments, 100 parts by weight of hydroxyl-terminated polydimethylsiloxane are reacted with 2 to 5 parts by weight of aminopropyltrialkoxysilane in the presence of 0.1 to 0.5 parts by weight of alkaline gel catalyst.
[0016] In some embodiments, the reaction conditions of the terminal hydroxyl polydimethylsiloxane with aminopropyltrialkoxysilane include: 60–75°C under vacuum; for example, about 60°C, 65°C, 70°C, 75°C, etc.
[0017] In some embodiments, the hydroxyl-terminated polydimethylsiloxane is pretreated, the pretreatment including vacuum dehydration.
[0018] In some embodiments, after the step of reacting terminal hydroxyl polydimethylsiloxane with aminopropyltrialkoxysilane in the presence of an alkaline gel catalyst, the steps further include: heating to destroy the alkaline gel catalyst; and vacuum removal of low molecular weight compounds.
[0019] In some embodiments, the preparation method of the terminal dialkoxyaminopropyl polydimethylsiloxane includes: preparing the alkaline gel catalyst by reacting tetramethylammonium hydroxide with dimethylcyclotetrasiloxane under vacuum at 50-70°C; preparing the terminal dialkoxyaminopropyl polydimethylsiloxane by reacting 100 parts by weight of dehydrated terminal hydroxyl polydimethylsiloxane, 0.1-0.5 parts by weight of the alkaline gel catalyst and 2-5 parts by weight of aminopropyltrialkoxysilane under vacuum at 60-75°C; and optionally, a subsequent step: heating to 140-150°C to destroy the alkaline gel catalyst, and then removing low molecular weight compounds under vacuum.
[0020] In some embodiments, the alkoxysilane crosslinking agent includes at least one of the following: methyl orthosilicate, ethyl orthosilicate, vinyltrimethoxysilane, vinyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane.
[0021] In some embodiments, the organotin catalyst includes at least one of the following: dibutyltin dilaurate and dibutyltin dioctanoate.
[0022] In some embodiments, the raw materials of the one-component dealcoholized room temperature vulcanizing silicone sealant include, by weight parts:
[0023] 100 parts terminal diekoxyaminopropyl polydimethylsiloxane;
[0024] 100-200 parts of reinforcing filler; for example, the number of parts of reinforcing filler can be approximately 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200 parts, etc.
[0025] 3 to 8 parts of alkoxysilane crosslinking agent; for example, the number of parts of alkoxysilane crosslinking agent can be about 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, etc.
[0026] 0.1 to 1 part of organotin catalyst; for example, the amount of organotin catalyst can be about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 part, etc.
[0027] A second aspect of the present invention provides a method for preparing the single-component dealcohol-type room temperature vulcanizing silicone sealant, comprising: weighing each raw material according to the weight parts; mixing the terminal alkoxyaminopropyl polydimethylsiloxane and reinforcing filler; heating and vacuuming and stirring to prepare a first material; adding an alkoxysilane crosslinking agent to the first material; continuing to heat and vacuum and stirring to prepare a second material; adding an organotin catalyst to the second material; vacuuming and stirring; and then cooling to room temperature before discharging to obtain the single-component dealcohol-type room temperature vulcanizing silicone sealant.
[0028] In some embodiments, the reinforcing filler is pretreated, the pretreatment including drying and dehydration.
[0029] Compared with the prior art, the technical solution of the present invention has the following advantages:
[0030] (1) This invention provides a one-component, alcohol-free, room-temperature vulcanizing silicone sealant. This room-temperature vulcanizing silicone sealant exhibits good adhesion to fluoroplastics, fluororubbers, and fluorosilicone rubbers with high surface inertness and low surface energy, achieving excellent bonding. Furthermore, it possesses good mechanical properties and exhibits good stability under long-term storage conditions.
[0031] (2) The single-component de-alcoholized room temperature vulcanizing silicone sealant provided by the present invention uses terminal dialkoxyaminopropyl polydimethylsiloxane as the base adhesive. The present invention also provides a preparation method for terminal dialkoxyaminopropyl polydimethylsiloxane as the base adhesive. The preparation method is simple to operate, and the purity and yield of the product can meet the needs of industrial applications.
[0032] (3) This invention also provides a method for preparing a one-component dealcohol-type room temperature vulcanizing silicone sealant. This method yields a one-component dealcohol-type room temperature vulcanizing silicone sealant with excellent properties. The preparation method is simple, easy to operate, and highly stable, and has broad prospects for industrial application. Attached Figure Description
[0033] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. In the drawings:
[0034] Figure 1 According to some embodiments of the present invention, the damping performance test results of a single-component high-adhesion de-alcoholized room temperature vulcanizing silicone sealant are presented. Detailed Implementation
[0035] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
[0036] Unless otherwise specified in the following detailed embodiments, conventional experimental procedures and commercially available reagents in the art are used. In each embodiment, the amount of raw materials used is expressed in "parts" or "parts by weight," both referring to parts by weight.
[0037] The raw materials and their amounts used in the following examples and comparative examples are shown in Table 1.
[0038] Table 1. Components and dosages in room temperature vulcanizing silicone sealant formulations.
[0039]
[0040]
[0041] Example 1
[0042] (1) Preparation of terminal dimethoxyaminopropyl polydimethylsiloxane
[0043] First, in a vacuum reactor, 1 part tetramethylammonium hydroxide and 100 parts dimethylcyclotetrasiloxane were reacted under vacuum at 60°C for 3.5 h to remove the generated water, thus preparing an alkaline gel catalyst. Then, in the same vacuum reactor, 100 parts of hydroxyl-terminated polydimethylsiloxane (viscosity 10540 mPa·s) were dehydrated under vacuum at 100°C for 3.0 h.
[0044] In a vacuum reactor, 100 parts of dehydrated hydroxyl-terminated polydimethylsiloxane, 0.4 parts of alkaline gel catalyst, and 3 parts of aminopropyltrimethoxysilane were reacted under vacuum at 60°C for 3.0 h; then the temperature was raised to 140°C to destroy the alkaline gel catalyst, and low molecular weight compounds were removed under vacuum to obtain hydroxyl-terminated aminopropylpolydimethylsiloxane.
[0045] The viscosity of the prepared terminal dimethoxyaminopropyl polydimethylsiloxane was 10860 mPa·s. When 100 parts of the prepared terminal dimethoxyaminopropyl polydimethylsiloxane were mixed with 1 part of tetrabutyl titanate, the viscosity remained almost unchanged during the mixing process, indicating that the end-capping rate was close to 100%.
[0046] (2) Preparation of a single-component, high-adhesion, alcohol-free, room-temperature vulcanizing silicone sealant
[0047] In an oven, the filler was dried at a temperature above 100°C for 5.0 hours to remove moisture. According to Table 1, each component was weighed. 100 parts by weight of terminal dimethoxyaminopropyl polydimethylsiloxane and 150 parts by weight of talc were placed in a vacuum kneader, heated to 60°C, and subjected to vacuum and uniform stirring. Then, 4 parts by weight of tetraethyl orthosilicate were added, and the mixture was heated to 60°C, subjected to vacuum and uniform stirring. Next, 0.7 parts by weight of dibutyltin dilaurate were added, and the mixture was further vacuumed and stirred uniformly at 60°C for a period of time. After cooling to room temperature, the mixture was discharged and sealed in a plastic packaging tube.
[0048] Example 2
[0049] Except for the following steps, and the raw material components and dosages according to Table 1, the same operation as in Example 1 was performed to prepare a single-component high-adhesion de-alcoholized room temperature vulcanizing silicone sealant.
[0050] Hydroxyl-terminated polydimethylsiloxane with a viscosity of 12940 mPa·s was used as the raw material; the viscosity of the prepared dimethoxyaminopropyl polydimethylsiloxane was 13190 mPa·s. When 100 parts of the prepared dimethoxyaminopropyl polydimethylsiloxane were mixed with 1 part of tetrabutyl titanate, the viscosity remained almost unchanged during the mixing process, indicating that the end-capping rate was close to 100%.
[0051] Example 3
[0052] Except for the following steps, and the raw material components and dosages according to Table 1, the same operation as in Example 1 was performed to prepare a single-component high-adhesion de-alcoholized room temperature vulcanizing silicone sealant.
[0053] Hydroxyl-terminated polydimethylsiloxane with a viscosity of 22520 mPa·s was used as the raw material; the viscosity of the prepared dimethoxyaminopropyl polydimethylsiloxane was 23660 mPa·s. When 100 parts of the prepared dimethoxyaminopropyl polydimethylsiloxane were mixed with 1 part of tetrabutyl titanate, the viscosity remained almost unchanged during the mixing process, indicating that the end-capping rate was close to 100%.
[0054] Example 4
[0055] Except for the following steps, and the raw material components and dosages according to Table 1, the same operation as in Example 1 was performed to prepare a single-component high-adhesion de-alcoholized room temperature vulcanizing silicone sealant.
[0056] Hydroxyl-terminated polydimethylsiloxane with a viscosity of 12940 mPa·s was used as the raw material, and aminopropyltrimethoxysilane was replaced with aminopropyltriethoxysilane to prepare terminally ethoxyaminopropyl polydimethylsiloxane with a viscosity of 13250 mPa·s. When 100 parts of the prepared terminally ethoxyaminopropyl polydimethylsiloxane were mixed with 1 part of tetrabutyl titanate, the viscosity remained almost unchanged during the mixing process, indicating that the end-capping rate was close to 100%.
[0057] Example 5
[0058] Except for the following steps, and the raw material components and dosages according to Table 1, the same operation as in Example 4 was performed to prepare a single-component high-adhesion de-alcoholized room temperature vulcanizing silicone sealant.
[0059] Hydroxyl-terminated polydimethylsiloxane with a viscosity of 52120 mPa·s was used as the raw material, and aminopropyltrimethoxysilane was replaced with aminopropyltriethoxysilane; the viscosity of the prepared diethoxyaminopropylpolydimethylsiloxane was 55650 mPa·s. When 100 parts of the prepared diethoxyaminopropylpolydimethylsiloxane were mixed with 1 part of tetrabutyl titanate, the viscosity remained almost unchanged during the mixing process, indicating that the end-capping rate was close to 100%.
[0060] Comparative Examples 1-5
[0061] Except for the raw material components and dosages as per Table 1, the same procedure as in Example 3 was followed to prepare a dealcohol-type room temperature vulcanizing silicone sealant.
[0062] Experimental Example
[0063] Performance tests were conducted on the room temperature vulcanizing silicone sealants prepared in Examples 1-5 and Comparative Examples 1-5. First, standard test pieces of the room temperature vulcanizing silicone sealants were prepared using a polytetrafluoroethylene mold according to HB 5246. Then, hardness, tensile strength, elongation at break, and 180° peel strength were tested. Hardness, tensile strength, and elongation at break were tested again after one year of storage at room temperature. Specifically: the hardness of the room temperature vulcanizing silicone sealant was tested according to GB / T 531-1999; the tensile strength and elongation at break were tested according to GB / T 528-2008; and the 180° peel strength was tested according to HB 5249-1993. The test results are shown in Table 2. The loss factor of the room temperature vulcanizing silicone sealant at -50℃ to 200℃ was tested using the single cantilever beam method (at a frequency of 2.0Hz). The test results are shown in Table 2. Figure 1 As shown.
[0064] Table 2 Performance test results of room temperature vulcanizing silicone sealant
[0065]
[0066]
[0067] As shown in Table 2, the de-alcoholized silicone sealant prepared using terminal dialkoxyaminopropyl polydimethylsiloxane as the base adhesive exhibits good adhesion to substrates that are extremely difficult to bond, such as fluoroplastics, fluororubbers, and fluorosilicone rubbers, while also possessing excellent storage stability. Figure 1 It can be seen that the loss factor of the silicone sealant of the present invention is higher than 0.1 in the range of -50℃ to 200℃, which indicates that the silicone sealant has excellent damping and vibration reduction performance over a wide temperature range.
[0068] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A one-component, alcohol-free, room-temperature vulcanizing silicone sealant, characterized in that, The raw materials comprised by weight are: 100 parts of terminal dialkoxyaminopropyl polydimethylsiloxane, 100-200 parts of reinforcing filler, 3-8 parts of alkoxysilane crosslinking agent, and 0.1-1 parts of organotin catalyst; the reinforcing filler includes sheet-like filler, wherein the sheet-like filler accounts for more than 50% by mass in the reinforcing filler. The preparation method of the terminal dialkoxyaminopropyl polydimethylsiloxane includes: reacting terminal hydroxyl polydimethylsiloxane with aminopropyltrialkoxysilane in the presence of an alkaline gel catalyst to obtain terminal dialkoxyaminopropyl polydimethylsiloxane; wherein the alkaline gel catalyst is prepared by reacting tetramethylammonium hydroxide with dimethylcyclotetrasiloxane.
2. The single-component, alcohol-free, room-temperature vulcanizing silicone sealant as described in claim 1, characterized in that, The sheet-like filler includes at least one of the following: mica powder, zirconium phosphate, and talc powder.
3. The single-component, alcohol-free, room-temperature vulcanizing silicone sealant as described in claim 1, characterized in that, In addition to the sheet-like filler, the reinforcing filler also includes at least one selected from the group consisting of zinc oxide, silica powder, quartz powder, calcium carbonate, and silica.
4. The single-component, alcohol-free, room-temperature vulcanizing silicone sealant as described in claim 1, characterized in that, The viscosity of the terminal dialkoxyaminopropyl polydimethylsiloxane is 5000–80000 mPa·s.
5. The single-component, alcohol-free, room-temperature vulcanizing silicone sealant as described in claim 1, characterized in that, By weight, 100 parts of hydroxyl-terminated polydimethylsiloxane are reacted with 2 to 5 parts of aminopropyltrialkoxysilane.
6. The single-component, alcohol-free, room-temperature vulcanizing silicone sealant as described in claim 1, characterized in that, By weight, 100 parts of hydroxyl-terminated polydimethylsiloxane and 2-5 parts of aminopropyltrialkoxysilane are reacted in the presence of 0.1-0.5 parts of alkaline gel catalyst.
7. The single-component, alcohol-free, room-temperature vulcanizing silicone sealant as described in claim 1, characterized in that, The reaction conditions for the terminal hydroxyl polydimethylsiloxane with aminopropyltrialkoxysilane include: 60–75°C under vacuum.
8. The single-component, alcohol-free, room-temperature vulcanizing silicone sealant as described in claim 1, characterized in that, The hydroxyl-terminated polydimethylsiloxane is pretreated, and the pretreatment includes vacuum dehydration.
9. The single-component, alcohol-free, room-temperature vulcanizing silicone sealant as described in claim 1, characterized in that, The alkoxysilane crosslinking agent includes at least one of the following: methyl orthosilicate, ethyl orthosilicate, vinyltrimethoxysilane, vinyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane.
10. The single-component, alcohol-free, room-temperature vulcanizing silicone sealant as described in claim 1, characterized in that, The organotin catalyst includes at least one of the following: dibutyltin dilaurate and dibutyltin dioctanoate.
11. The method for preparing the single-component, alcohol-free, room-temperature vulcanizing silicone sealant according to any one of claims 1 to 10, characterized in that, include: Weigh each raw material according to the specified weight proportions, mix the terminal alkoxyaminopropyl polydimethylsiloxane and reinforcing filler, heat and vacuum and stir to prepare the first material; add alkoxysilane crosslinking agent to the first material, continue heating and vacuuming and stirring to prepare the second material; add organotin catalyst to the second material, vacuum and stir, then cool to room temperature and discharge to prepare the single-component dealcoholized room temperature vulcanizing organosilicon sealant.
12. The method for preparing a single-component, dealcohol-free, room-temperature vulcanizing silicone sealant as described in claim 11, characterized in that, The reinforcing filler undergoes pretreatment, which includes drying and dehydration.