Crosslinking curing agent for dealcoholized organosilicon sealant and preparation method of crosslinking curing agent

Abstract

The invention provides a crosslinking curing agent for a dealcoholized organosilicon sealant and a preparation method of the crosslinking curing agent. Comprising the following components in parts by weight: 55 to 75 parts of polymethyl triethoxysilane, 15 to 35 parts of orthosilicate, 1 to 2 parts of amino alkoxy silane, 4 to 6 parts of secondary amino bis (trialkoxy) silane, 1 to 2 parts of epoxy trialkoxy silane, 1.4 to 1.7 parts of acetic acid acetyl ethyl ester, 0.1 to 0.2 part of anhydrous nickel chloride and 0.1 to 0.5 part of an organic tin catalyst. The cross-linking curing agent has dual functions of a traditional cross-linking agent and a coupling agent, has high stability and high performance at the same time, can realize a preparation process of replacing alkoxy-terminated 107 on the basis of conventional hydroxyl-terminated 107 when being applied to a double-component alcohol type adhesive and an alcohol type transparent adhesive, ensures a good storage period and better mechanical properties, and is suitable for industrial production. And finally, the production, the performance and the cost are greatly optimized.

Description

Technical Field

[0001] The invention relates to the technical field of dealcoholized organosilicon sealants, and in particular to a cross-linking curing agent for dealcoholized organosilicon sealants and a preparation method thereof. Background Art

[0002] In the decarbinolation type transparent silicone sealant and two-component alcohol type adhesive system, organic tin catalysis is currently generally used instead of titanium catalysis. Due to the transparency requirement, decarbinolation type transparent silicone sealant cannot use titanium catalysis; two-component alcohol type adhesive also needs to choose tin catalysis because titanium catalysis seriously affects the overall curing effect of the adhesive, and the viscosity peak brings production difficulties. Furthermore, under ordinary decarbinolation type crosslinking agents and tin catalysis, decarbinolation type transparent silicone sealant has strict requirements on the selection of 107 glue. A large amount of experimental data and professional works have proved that conventional hydroxyl-terminated 107 is very likely to cause gel and dry glue in this case, and only alkoxy-terminated 107 can be selected as the basis for preparation. However, compared with hydroxyl-terminated 107, due to the complex synthesis process of alkoxy-terminated 107, the market price is generally higher, which ultimately leads to a significant increase in product costs. On the other hand, the same problem still exists in the preparation of two-component dealcoholized silicone sealants. Although sometimes component B can choose to replace 107 with silicone oil, combined with ordinary dealcoholized cross-linking agents and tin catalysts to avoid the problem of gel dry glue, the two-component silicone sealant prepared based on silicone oil not only has certain restrictions on the content of silicone oil. When the content exceeds a certain amount, the glue is prone to oil seepage and the surface becomes sticky. In addition, its mechanical properties and storage properties are poor. Summary of the invention

[0003] The present invention provides a cross-linking curing agent for dealcoholized organosilicon sealant and a preparation method thereof, the purpose of which is to solve the above-mentioned problems existing in the background technology.

[0004] In order to achieve the above object, an embodiment of the present invention provides a cross-linking curing agent for a dealcoholized silicone sealant, which comprises the following components in parts by weight:

[0005] 55-75 parts of polymethyltriethoxysilane, 15-35 parts of orthosilicate, 1-2 parts of aminoalkoxysilane, 4-6 parts of secondary aminobistrialkoxysilane, 1-2 parts of epoxytrialkoxysilane, 1.4-1.7 parts of ethyl acetate, 0.1-0.2 parts of anhydrous nickel chloride and 0.1-0.5 parts of an organic tin catalyst.

[0006] Preferably, the degree of polymerization of the polymethyltriethoxysilane is 3-6.

[0007] Preferably, the orthosilicate is at least one of methyl orthosilicate, ethyl orthosilicate and propyl orthosilicate.

[0008] Preferably, the aminoalkoxysilane is at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-aminoethyl-γ-aminopropyltrimethoxysilane, and amino-modified silane oligomer.

[0009] Preferably, the epoxytrialkoxysilane is at least one of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0010] Preferably, the organic tin catalyst is at least one of dibutyltin dilaurate and dibutyltin diacetate.

[0011] Preferably, the dealcoholization type silicone sealant includes a two-component dealcoholization type silicone sealant and a one-component dealcoholization type transparent silicone sealant.

[0012] Based on a general concept of the invention, an embodiment of the present invention provides a method for preparing the above-mentioned cross-linking curing agent for dealcoholized silicone sealant, comprising the following steps:

[0013] S1: 55-75 parts of polymethyltriethoxysilane and 15-35 parts of orthosilicate are placed in a reaction kettle, and 1.4-1.7 parts of ethyl acetate and 0.1-0.2 parts of anhydrous nickel chloride are added in sequence, stirred and heated to 60-70°C, reacted under dry nitrogen protection for 1-2 hours, cooled and filtered, and the filtrate is distilled under reduced pressure to obtain polymer A;

[0014] S2: 1-2 parts of epoxytrialkoxysilane and 0.1-0.5 parts of organotin catalyst are placed in another reaction kettle, heated to 80-90°C under nitrogen protection and stirring, 1-2 parts of aminoalkoxysilane are added dropwise within 1 hour, reacted for 2 hours, and distilled under reduced pressure to obtain polymer B;

[0015] S3: Add the polymer A and 4 to 6 parts of secondary aminobistrialkoxysilane to polymer B in sequence, stir under nitrogen protection, keep the temperature at 80 to 90° C., further undergo random copolymerization, react for 2 to 3 hours, perform reduced pressure distillation and filtration, and obtain a cross-linking curing agent.

[0016] The invention is realized based on the following principles: in the first step, polymethyltriethoxysilane, orthosilicate and ethyl acetate are heated to a suitable temperature and for a sufficient time to undergo ester exchange and chain extension reactions with anhydrous nickel chloride as a reaction catalyst, and the obtained polymer A is a silicon-oxygen copolymer with a high degree of polymerization and an alkoxyl group or alkoxyl active functional group at the end of the alkoxyl group. Under the preferred weight fraction of the invention, the obtained polymer A has a high purity; in the second step, polymer B is a polymer blend containing amino, epoxy or hydroxyl active functional groups obtained by ring-opening polymerization of epoxytrialkoxysilane and aminoalkoxysilane in the presence of an organic tin catalyst; in the third step, secondary aminobistrialkoxysilane is used as an intermediate, six alkoxy groups at both ends are used as "mobile bridges", and in the presence of organic tin, at a suitable temperature and for a sufficient time, a random copolymerization reaction of polymer A and polymer B is further realized, and a cross-linking curing agent is finally obtained.

[0017] The above scheme of the present invention has the following beneficial effects:

[0018] The cross-linking curing agent of the present invention has the dual functions of a traditional cross-linking agent and a coupling agent, and has high stability and high performance. Especially when applied to two-component alcohol-type adhesive and alcohol-type transparent adhesive, it can realize the preparation process based on conventional hydroxyl-terminated 107 instead of alkoxy-terminated 107, and ensure a good storage period and better mechanical properties, and ultimately the production performance and cost are greatly optimized. DETAILED DESCRIPTION

[0019] In order to make the technical problems to be solved, technical solutions and advantages of the present invention more clear, they are described in detail below in conjunction with specific embodiments.

[0020] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0021] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0022] In view of the existing problems, the present invention provides a cross-linking curing agent for dealcoholized organosilicon sealant, which comprises the following components in parts by weight:

[0023] 55-75 parts of polymethyltriethoxysilane, 15-35 parts of orthosilicate, 1-2 parts of aminoalkoxysilane, 1-2 parts of epoxytrialkoxysilane, 1.4-1.7 parts of ethyl acetate, 0.1-0.2 parts of anhydrous nickel chloride and 0.1-0.5 parts of an organic tin catalyst.

[0024] Preferably, the degree of polymerization of the polymethyltriethoxysilane is 3-6.

[0025] Preferably, the orthosilicate is at least one of methyl orthosilicate, ethyl orthosilicate and propyl orthosilicate.

[0026] Preferably, the aminoalkoxysilane is at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-aminoethyl-γ-aminopropyltrimethoxysilane, and amino-modified silane oligomer.

[0027] Preferably, the epoxytrialkoxysilane is at least one of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0028] Preferably, the organic tin catalyst is at least one of dibutyltin dilaurate and dibutyltin diacetate.

[0029] Preferably, the dealcoholization type silicone sealant includes a two-component dealcoholization type silicone sealant and a one-component dealcoholization type transparent silicone sealant.

[0030] Based on a general concept of the invention, an embodiment of the present invention provides a method for preparing the above-mentioned cross-linking curing agent for dealcoholized silicone sealant, comprising the following steps:

[0031] S1: 55-75 parts of polymethyltriethoxysilane and 15-35 parts of orthosilicate are placed in a reaction kettle, and 1.4-1.7 parts of ethyl acetate and 0.1-0.2 parts of anhydrous nickel chloride are added in sequence, stirred and heated to 60-70°C, reacted under dry nitrogen protection for 1-2 hours, cooled and filtered, and the filtrate is distilled under reduced pressure to obtain polymer A;

[0032] S2: 1-2 parts of epoxytrialkoxysilane and 0.1-0.5 parts of organotin catalyst are placed in another reaction kettle, heated to 80-90°C under nitrogen protection and stirring, 1-2 parts of aminoalkoxysilane are added dropwise within 1 hour, reacted for 2 hours, and distilled under reduced pressure to obtain polymer B;

[0033] S3: Add the polymer A and 4 to 6 parts of secondary aminobistrialkoxysilane to polymer B in sequence, stir under nitrogen protection, keep the temperature at 80 to 90° C., further undergo random copolymerization, react for 2 to 3 hours, perform reduced pressure distillation and filtration, and obtain a cross-linking curing agent.

[0034] The following is a detailed description through specific embodiments.

[0035] Example 1

[0036] A method for preparing a dealcoholized organosilicon cross-linking curing agent comprises the following steps:

[0037] S1: 55 parts of polymethyltriethoxysilane with a polymerization degree of 3 and 35 parts of ethyl orthosilicate were placed in a reaction kettle, 1.4 parts of ethyl acetate and 0.1 parts of anhydrous nickel chloride were added in sequence, the mixture was stirred and heated to 60-70°C, and the mixture was reacted for 1-2 hours under the protection of dry nitrogen, cooled and filtered, and the filtrate was distilled under reduced pressure to obtain polymer A;

[0038] S2: 1 part of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.2 part of dibutyltin dilaurate were placed in another reaction kettle, heated to 80-90°C under nitrogen protection and stirring, and a mixture of 1 part of γ-aminopropyltrimethoxysilane and 1 part of amino-modified silane oligomer (Evonik 1146) was added dropwise within 1 hour, reacted for 2 hours, and distilled under reduced pressure to obtain polymer B;

[0039] S3: Add the above polymer A and 5.3 parts of secondary aminobistrimethoxypropylsilane to polymer B in sequence, stir under nitrogen protection, keep the temperature at 80-90° C., react for 2-3 hours, and then distill and filter under reduced pressure to obtain crosslinking curing agent 1.

[0040] Example 2

[0041] A method for preparing a dealcoholized organosilicon cross-linking curing agent comprises the following steps:

[0042] S1: 75 parts of polymethyltriethoxysilane with a polymerization degree of 6 and 15 parts of methyl orthosilicate were placed in a reaction kettle, 1.7 parts of ethyl acetate and 0.2 parts of anhydrous nickel chloride were added in sequence, the mixture was stirred and heated to 60-70°C, and the mixture was reacted for 1-2 hours under the protection of dry nitrogen, cooled and filtered, and the filtrate was distilled under reduced pressure to obtain polymer A;

[0043] S2: 2 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.1 parts of dibutyltin dilaurate were placed in another reaction kettle, heated to 80-90°C under nitrogen protection and stirring, and a mixture of 1 part of γ-aminopropyltriethoxysilane and 1 part of amino-modified silane oligomer (Jianghan New Materials JH-AP1231) was added dropwise within 1 hour, reacted for 2 hours, and distilled under reduced pressure to obtain polymer B;

[0044] S3: Add the above polymer A and 4 parts of secondary aminobistrimethoxypropylsilane to polymer B in sequence, stir under nitrogen protection, keep the temperature at 80-90° C., react for 2-3 hours, and then distill and filter under reduced pressure to obtain crosslinking curing agent 2.

[0045] Example 3

[0046] A method for preparing a two-component dealcoholized organosilicon sealant comprises the following steps:

[0047] (1) 100 parts by weight of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 20,000 MPa.s at 25° C. was added into a planetary mixer, and 120 parts by weight of nano-activated calcium carbonate was added in batches. The temperature was 50° C., the vacuum degree was maintained at -0.090 to -0.100 MPa, the rotation speed was 20 Hz, and the stirring was performed for 60 min to obtain component A.

[0048] (2) 100 parts by weight of 20,000 MPa.s α,ω-dihydroxypolydimethylsiloxane and 120 parts by weight of heavy calcium carbonate were stirred and dispersed uniformly, and vacuum was applied. 7.5 parts by weight of cross-linking curing agent 1 were added, the temperature was 50° C., the vacuum degree was maintained at -0.095 to -0.100 MPa, the rotation speed was 20 Hz, and stirring was performed for 45 minutes to obtain component B.

[0049] (3) Component A and component B are mixed in a mass ratio of 1:1 to prepare a two-component dealcoholized silicone sealant.

[0050] Comparative Example 1

[0051] A method for preparing a two-component dealcoholized organosilicon sealant comprises the following steps:

[0052] (1) 100 parts by weight of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 20,000 MPa.s at 25° C. was added into a planetary mixer, and 120 parts by weight of nano-activated calcium carbonate was added in batches. The temperature was 50° C., the vacuum degree was maintained at -0.090 to -0.100 MPa, the rotation speed was 20 Hz, and the stirring was performed for 60 min to obtain component A.

[0053] (2) 100 parts by weight of 20,000 MPa.s α,ω-dihydroxypolydimethylsiloxane and 120 parts by weight of heavy calcium carbonate were stirred and dispersed uniformly, and vacuum was applied. 5.5 parts by weight of polymethyltriethoxysilane was added and stirred in vacuum for 15 min. 1.6 parts by weight of γ-aminopropyltriethoxysilane and 0.4 parts by weight of dibutyltin dilaurate were added, and the vacuum degree was maintained at -0.095 to -0.100 MPa. The rotation speed was 20 Hz and the mixture was stirred for 30 min to obtain component B.

[0054] (3) Component A and component B are mixed in a mass ratio of 1:1 to prepare a two-component dealcoholized silicone sealant.

[0055] Comparative Example 2

[0056] A method for preparing a two-component dealcoholized organosilicon sealant comprises the following steps:

[0057] (1) 100 parts by weight of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 20,000 MPa.s at 25° C. was added into a planetary mixer, and 120 parts by weight of nano-activated calcium carbonate was added in batches. The temperature was 50° C., the vacuum degree was maintained at -0.090 to -0.100 MPa, the rotation speed was 20 Hz, and the stirring was performed for 60 min to obtain component A.

[0058] (2) 100 parts by weight of 20,000 MPa.s trialkoxysilyl-terminated polydimethylsiloxane and 120 parts by weight of heavy calcium carbonate were stirred and dispersed uniformly, and vacuum was applied. 5.5 parts by weight of polymethyltriethoxysilane were added and stirred in vacuum for 15 min. 1.6 parts by weight of γ-aminopropyltriethoxysilane and 0.4 parts by weight of dibutyltin dilaurate were added, and the vacuum degree was maintained at -0.095 to -0.100 MPa. The rotation speed was 20 Hz and the mixture was stirred for 30 min to obtain component B.

[0059] (3) Component A and component B are mixed in a mass ratio of 1:1 to prepare a two-component dealcoholized silicone sealant.

[0060] Example 4

[0061] A method for preparing a one-component dealcoholized transparent silicone sealant comprises the following steps:

[0062] Into a planetary mixer, 100 parts by weight of α,ω-dihydroxypolydimethylsiloxane at 20000 MPa.s was added, and 8 parts by weight of fumed silica was added in batches. The mixture was slowly vacuumed and stirred to be uniformly dispersed. Then, 8 parts by weight of cross-linking curing agent 2 was added. The temperature was 50°C, the vacuum degree was maintained at -0.095 to -0.100 MPa, the rotation speed was 20 Hz, and stirring was performed for 45 minutes to obtain a one-component dealcoholization transparent silicone sealant.

[0063] Comparative Example 3

[0064] A method for preparing a one-component dealcoholized transparent silicone sealant comprises the following steps:

[0065] Into a planetary mixer, 100 parts by weight of α,ω-dihydroxypolydimethylsiloxane at 20000 MPa.s was added, and 8 parts by weight of fumed silica was added in batches. Vacuum was slowly drawn, and after uniform dispersion was achieved through stirring, 5.5 parts by weight of polymethyltriethoxysilane was added. The mixture was stirred in vacuum for 15 minutes, and 1.6 parts by weight of γ-aminopropyltriethoxysilane and 0.4 parts by weight of dibutyltin dilaurate were continuously added. The vacuum degree was maintained at -0.095 to -0.100 MPa, the rotation speed was 20 Hz, and the mixture was stirred for 30 minutes to obtain a single-component dealcoholization transparent silicone sealant.

[0066] Comparative Example 4

[0067] A method for preparing a one-component dealcoholized transparent silicone sealant comprises the following steps:

[0068] Into a planetary mixer, 100 parts by weight of trialkoxysilyl-terminated polydimethylsiloxane at 20000 MPa.s was added, and 8 parts by weight of fumed silica was added in batches. Vacuum was slowly drawn, and after uniform dispersion was achieved through stirring, 5.5 parts by weight of polymethyltriethoxysilane was added. The mixture was stirred in vacuum for 15 minutes, and 1.6 parts by weight of γ-aminopropyltriethoxysilane and 0.4 parts by weight of dibutyltin dilaurate were continuously added. The vacuum degree was maintained at -0.095 to -0.100 MPa, the rotation speed was 20 Hz, and the mixture was stirred for 30 minutes to obtain a one-component dealcoholization transparent silicone sealant.

[0069] The physical properties of the above Examples 3 to 4 and Comparative Examples 1 to 4 were tested, and the physical property results are shown in Table 1 below.

[0070] Table 1

[0071]

[0072]

[0073] As can be seen from Table 1, Example 3, Comparative Example 1 and Comparative Example 2 are all preparation processes for two-component dealcoholization type silicone sealants, but the final effects are quite different. Comparative Example 1 uses hydroxyl-terminated 107 as the basis, and the preparation process with conventional dealcoholization type crosslinking agent, coupling agent, and organotin catalyst is completely unfeasible, while Example 3 uses hydroxyl-terminated 107 as the basis, and the preparation process compounded with a dealcoholization type silicone crosslinking curing agent provided by the present invention is successful. Compared with the preparation process using alkoxy-terminated 107 as the basis in Comparative Example 2, the two-component dealcoholization type silicone sealant prepared in Example 3 not only has good adhesion, but also has better storage life and better mechanical properties; Example 4 Comparative Examples 3 and 4 are both preparation processes for single-component dealcoholization transparent silicone sealants, but the final effects are also quite different. The preparation process of Comparative Example 3 using hydroxyl-terminated 107 as the basis, compounded with fumed silica, conventional dealcoholization crosslinking agent, coupling agent, and organic tin catalyst is completely unfeasible, while the preparation process of Example 4 using hydroxyl-terminated 107 as the basis, compounded with fumed silica, and a dealcoholization silicone crosslinking curing agent provided by the present invention is feasible, and compared with the preparation process of Comparative Example 4 using alkoxy-terminated 107 as the basis, the single-component dealcoholization transparent silicone sealant prepared in Example 4 has good adhesion, better storage life and better mechanical properties.

[0074] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A cross-linking curing agent for dealcoholized silicone sealant, characterized in that: According to parts by weight, it includes the following components: 55-75 parts of polymethyltriethoxysilane, 15-35 parts of orthosilicate, 1-2 parts of aminoalkoxysilane, 4-6 parts of secondary aminobistrialkoxysilane, 1-2 parts of epoxytrialkoxysilane, 1.4-1.7 parts of ethyl acetate, 0.1-0.2 parts of anhydrous nickel chloride and 0.1-0.5 parts of an organic tin catalyst.

2. The cross-linking curing agent for dealcoholized silicone sealant according to claim 1, characterized in that: The polymerization degree of the polymethyltriethoxysilane is 3-6.

3. The cross-linking curing agent for dealcoholized silicone sealant according to claim 1, characterized in that: The orthosilicate is at least one of methyl orthosilicate, ethyl orthosilicate and propyl orthosilicate.

4. The cross-linking curing agent for dealcoholized organosilicon sealant according to claim 1, characterized in that: The aminoalkoxysilane is at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-aminoethyl-γ-aminopropyltrimethoxysilane, and amino-modified silane oligomer.

5. The cross-linking curing agent for dealcoholized organosilicon sealant according to claim 1, characterized in that: The epoxytrialkoxysilane is at least one of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

6. The cross-linking curing agent for dealcoholized organosilicon sealant according to claim 1, characterized in that: The organic tin catalyst is at least one of dibutyltin dilaurate and dibutyltin diacetate.

7. The method for preparing a crosslinking curing agent for a dealcoholized silicone sealant according to any one of claims 1 to 6, characterized in that: The steps include: S1: 55-75 parts of polymethyltriethoxysilane and 15-35 parts of orthosilicate are placed in a reaction kettle, and 1.4-1.7 parts of ethyl acetate and 0.1-0.2 parts of anhydrous nickel chloride are added in sequence, stirred and heated to 60-70°C, reacted under dry nitrogen protection for 1-2 hours, cooled and filtered, and the filtrate is distilled under reduced pressure to obtain polymer A; S2: 1-2 parts of epoxytrialkoxysilane and 0.1-0.5 parts of organotin catalyst are placed in another reaction kettle, heated to 80-90°C under nitrogen protection and stirring, 1-2 parts of aminoalkoxysilane are added dropwise within 1 hour, reacted for 2 hours, and distilled under reduced pressure to obtain polymer B; S3: Add the polymer A and 4 to 6 parts of secondary aminobistrialkoxysilane to the polymer B in sequence, stir under nitrogen protection, keep the temperature at 80 to 90° C., react for 2 to 3 hours, and then distill and filter under reduced pressure to obtain a cross-linking curing agent.

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