Dealcoholized single-component transparent silicone sealant and preparation method thereof

Abstract

The present application belongs to the technical field of dealcoholized single-component silicone sealant, and specifically discloses a kind of dealcoholized single-component transparent silicone sealant and preparation method, the dealcoholized single-component transparent silicone sealant, according to mass fraction, including alkoxyl end-capped polydimethylsiloxane: 100 parts;Fumed silica filler: 5-30 parts;Surface modifier: 2-10 parts;Crosslinking agent: 10-30 parts;Catalyst: 0.5-2 parts;Adhesion promoter: 0.5-2 parts;Wherein, the surface modifier is diisopropoxy aluminum of diacetyl acetic acid ethyl ester, acetyl acetic acid ethyl ester and vinyl trimethoxysilane are obtained under the condition of 60-80 DEG C for 2-3h and the reflux material of reaction.The dealcoholized single-component transparent silicone sealant prepared by the present application has excellent adhesion to glass, metal, PC, PBT, PET, PVC, ABS and other materials, excellent storage stability and transparency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dealcoholized single-component silicone sealant, in particular to a dealcoholized single-component transparent silicone sealant and a preparation method thereof. BACKGROUND

[0002] Room temperature vulcanized silicone rubber (RTV) has excellent resistance to ultraviolet light, aging and high temperature and humidity. As an important part of RTV silicone rubber, single-component room temperature vulcanized silicone sealant has been favored by many industries due to its excellent durability and ease of operation. The most widely used single-component room temperature vulcanized silicone sealant currently mainly includes dealcoholized, deketoxime, deacetic acid and deamidohydroxylamine products. The dealcoholized product has the advantages of no irritating odor, no corrosion to materials, no cracking during vulcanization, and good physical properties and electrical properties in harsh environments, and is a single-component RTV silicone rubber with good comprehensive performance, which is widely used in the fields of construction, electronic devices, lighting devices, mechanical equipment and automobiles.

[0003] There is a kind of transparent product in dealcoholized single-component silicone sealant. Due to the special requirements of transparency, there are many restrictions on the production raw materials of the product, such as polydimethylsiloxane-based glue, fillers, catalysts and tackifiers, and there are also many technical defects in the actual production process, for example:

[0004] (1) Poor bonding universality

[0005] Due to the many restrictions on the production raw materials of polydimethylsiloxane-based glue, fillers, catalysts and tackifiers, the dealcoholized single-component transparent silicone sealant commonly seen on the market can bond inorganic materials such as glass and metal, but the bonding stability and universality of organic materials such as PC, PBT, PET, PVC and ABS are obviously insufficient.

[0006] (2) Poor storage stability and easy thickening

[0007] In order to improve the mechanical properties, dealcoholized single-component transparent silicone sealant generally needs to add fumed silica filler. If the use process of fumed silica filler is improper, the sealant system will gradually thicken during storage at room temperature, thereby affecting the storage stability and use performance of the product.

[0008] (3) Poor transparency and easy whitening

[0009] Transparent silicone sealant is generally applied to the substrate with high appearance requirement, and the transparency index of the product has important influence on the appearance of the substrate. The transparency index of the dealcoholized single-component transparent silicone sealant is generally affected by the fillers, catalysts and tackifiers and other raw materials, and improper selection of the types and addition amount of the raw materials will result in poor transparency and whitish color of the product. SUMMARY

[0010] In view of the above-mentioned deficiencies, the present application provides a dealcoholized single-component transparent silicone sealant and a preparation method. The dealcoholized single-component transparent silicone sealant prepared by the present application has excellent adhesion to glass, metal, PC, PBT, PET, PVC, ABS and other materials, excellent storage stability and excellent transparency.

[0011] In order to achieve the above-mentioned purposes, the present application provides a dealcoholized single-component transparent silicone sealant, which comprises, in terms of mass fraction:

[0012]

[0013] The surface modifier is a refluxing product of diacetylacetate diisopropoxy aluminum, ethyl acetoacetate and vinyl trimethoxysilane under the condition of 60-80℃ for 2-3h.

[0014] According to an aspect of the present application, the mass ratio of the diacetylacetate diisopropoxy aluminum, ethyl acetoacetate and vinyl trimethoxysilane is 1:2:2.

[0015] According to an aspect of the present application, the adhesion promoter is a refluxing product of γ-aminopropyl trimethoxysilane, γ-glycidyl ether oxygen propyl trimethoxysilane, N-β-(aminoethyl)-aminopropyl methyl dimethoxysilane and γ-isocyanate propyl triethoxysilane under the condition of 100-120℃ for 2-3h.

[0016] According to an aspect of the present application, the mass ratio of the γ-aminopropyl trimethoxysilane, γ-glycidyl ether oxygen propyl trimethoxysilane, N-β-(aminoethyl)-aminopropyl methyl dimethoxysilane and γ-isocyanate propyl triethoxysilane is 1:2:1:0.5.

[0017] According to an aspect of the present application, the alkoxyl-terminated polydimethylsiloxane is α,ω-bis(trimethoxysilyl) polydimethylsiloxane, and the viscosity at 25℃ is 50-20000cp.

[0018] According to an aspect of the present application, the crosslinking agent is a complex mixed crosslinking agent of methyl trimethoxysilane and polymethyl trimethoxysilane, and the mass ratio of the methyl trimethoxysilane and the polymethyl trimethoxysilane is 1:1.

[0019] According to one aspect of the present application, the catalyst is a mixed organotin catalyst of dibutyl tin dilaurate and dibutyl tin diacetate; the mass ratio of dibutyl tin dilaurate to dibutyl tin diacetate is 6:4.

[0020] Based on the same inventive concept, the present application also provides a preparation method of the above-mentioned alcohol type single-component transparent organic silicone sealant, comprising the following steps:

[0021] S1, adding alkoxyl-terminated polydimethylsiloxane and fumed silica filler into a planetary machine, stirring to make the fumed silica filler fully melt into the alkoxyl-terminated polydimethylsiloxane, then adding a surface modifier into the planetary machine, and stirring and reacting under nitrogen protection for 20-40 min;

[0022] S2, adding a crosslinking agent into the planetary machine, and continuing to stir and react under nitrogen protection for 20-40 min;

[0023] S3, adding a catalyst and an adhesion promoter into the planetary machine, slowly vacuumizing and stirring for 8-20 min, continuing to stir and react after the vacuum reaches-0.095 MPa for 50-80 min, to obtain the dealcoholized single-component transparent organic silicone sealant.

[0024] The present application has the following advantages:

[0025] (1) The present application uses the reaction reflux material of ethyl acetoacetate diisopropoxy aluminum, ethyl acetoacetate and vinyl trimethoxysilane, which improves the surface adsorption and wettability of the added fumed silica in the system under the premise of ensuring high transparency of the dealcoholized single-component transparent organic silicone sealant, and further uses the reaction reflux material of γ-aminopropyl trimethoxysilane, γ-glycidyl ether propyl trimethoxysilane, N-β-(aminoethyl)-aminopropyl methyl dimethoxysilane and γ-isocyanate propyl triethoxysilane to promote the bonding universality of the system, so that the prepared dealcoholized single-component transparent organic silicone sealant has good bonding properties for both inorganic materials such as glass and metal and organic materials such as PC, PBT, PET, PVC and ABS.

[0026] (2) The present application uses the reaction reflux material of ethyl acetoacetate diisopropoxy aluminum, ethyl acetoacetate and vinyl trimethoxysilane, which successfully eliminates the excess water molecules in the system and the residual hydroxyl groups on the surface of the added fumed silica under the premise of ensuring high transparency of the dealcoholized single-component transparent organic silicone sealant, so that the prepared dealcoholized single-component transparent organic silicone sealant has good storage stability, does not show obvious thickening phenomenon after being stored for more than six months, and has a long service life.

[0027] (3) The present application adopts multiple raw materials with good compatibility, and the prepared dealcoholized single-component transparent silicone sealant has high transparency and does not appear the phenomenon of colloid whitening. DETAILED DESCRIPTION

[0028] In order to make the present application more easily understood, the present application is further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and are not used to limit the scope of the present application. Obviously, the described examples are only a part of the examples of the present application, but not all the examples. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor are within the scope of protection of the present application. Unless otherwise defined, the professional terms used below are consistent with the meanings understood by those skilled in the art; unless otherwise specified, the raw materials and reagents involved in the present application can be purchased from the market or prepared by known methods.

[0029] Example 1

[0030] A dealcoholized single-component transparent silicone sealant, according to mass fraction, raw materials are composed of the following components:

[0031]

[0032] Among them,

[0033] The surface modifier is a refluxing product obtained by reacting ethyl bisacetylacetate diisopropoxy aluminum, ethyl acetoacetate and vinyltrimethoxysilane at a mass ratio of 1:2:2 at 80°C for 2h.

[0034] The crosslinking agent is a mixed crosslinking agent obtained by compounding methyltrimethoxysilane and polymethyltrimethoxysilane at a mass ratio of 1:1.

[0035] The catalyst is a mixed organotin catalyst of dibutyltin dilaurate and dibutyltin diacetate at a mass ratio of 6:4.

[0036] The adhesion promoter is a refluxing product obtained by reacting γ-aminopropyltrimethoxysilane, γ-glycidyl ether propyltrimethoxysilane, N-β-(aminoethyl)-aminopropyl methyl dimethoxysilane and γ-isocyanate propyl triethoxysilane at a mass ratio of 1:2:1:0.5 at 120°C for 2h.

[0037] A preparation method of a dealcoholized single-component transparent silicone sealant, comprising the following steps:

[0038] (1) In the planetary machine, add alkoxyl-terminated polydimethylsiloxane and fumed silica filler in proportion, open the stirring to gradually make the fumed silica filler completely melt into the alkoxyl-terminated polydimethylsiloxane, then add the surface modifier in proportion to the planetary machine, and stir and react for 30 min under the condition of nitrogen protection;

[0039] (2) Add the crosslinking agent in proportion to the planetary machine, and continue to stir and react for 20 min under the condition of nitrogen protection;

[0040] (3) Add the catalyst and adhesion promoter in proportion to the planetary machine, slowly vacuumize and stir for 10 min, continue to stir and react for 60 min after the vacuum reaches-0.095 MPa, to obtain the dealcoholized single-component transparent silicone sealant.

[0041] Example 2

[0042] A dealcoholized single-component transparent silicone sealant, according to mass fraction, is composed of the following components:

[0043]

[0044] Among them,

[0045] The surface modifier is the refluxate obtained by reacting ethyl bisacetylacetate diisopropoxy aluminum, ethyl acetoacetate and vinyl trimethoxysilane in a mass ratio of 1:2:2 at 80°C for 2 h.

[0046] The crosslinking agent is a mixed crosslinking agent obtained by compounding methyl trimethoxysilane and polymethyl trimethoxysilane in a mass ratio of 1:1.

[0047] The catalyst is a mixed organotin catalyst of dibutyltin dilaurate and dibutyltin diacetate in a mass ratio of 6:4.

[0048] The adhesion promoter is the refluxate obtained by reacting γ-aminopropyl trimethoxysilane, γ-glycidyl ether propyl trimethoxysilane, N-β-(aminoethyl)-aminopropyl methyl dimethoxysilane and γ-isocyanate propyl triethoxysilane in a mass ratio of 1:2:1:0.5 at 120°C for 2 h.

[0049] A preparation method of a dealcoholized single-component transparent silicone sealant, comprising the following steps:

[0050] (1) In the planetary machine, add alkoxyl-terminated polydimethylsiloxane and fumed silica filler in proportion, open the stirring to gradually make the fumed silica filler completely melt into the alkoxyl-terminated polydimethylsiloxane, then add the surface modifier in proportion to the planetary machine, and stir and react for 30 min under the condition of nitrogen protection;

[0051] (2) to the planetary machine, add the crosslinking agent in proportion, continue stirring under the condition of nitrogen protection for 20 min;

[0052] (3) to the planetary machine, add the catalyst and the adhesion promoter in proportion, slowly vacuumize and stir for 10 min, continue stirring for 60 min after the vacuum reaches-0.095 MPa, and prepare the dealcoholized single-component transparent silicone sealant.

[0053] Example 3

[0054] A dealcoholized single-component transparent silicone sealant, according to mass fraction, the raw materials are composed of the following components:

[0055]

[0056] Among them,

[0057] The surface modifier is the refluxate obtained by reacting ethyl bisacetylacetate diisopropoxy aluminum, ethyl acetoacetate and vinyl trimethoxysilane in a mass ratio of 1:2:2 at 80°C for 2 h.

[0058] The crosslinking agent is a mixed crosslinking agent obtained by compounding methyl trimethoxysilane and polymethyl trimethoxysilane in a mass ratio of 1:1.

[0059] The catalyst is a mixed organotin catalyst of dibutyltin dilaurate and dibutyltin diacetate in a mass ratio of 6:4.

[0060] The adhesion promoter is the refluxate obtained by reacting γ-aminopropyl trimethoxysilane, γ-glycidyl ether propyl trimethoxysilane, N-β-(aminoethyl)-aminopropyl methyl dimethoxysilane and γ-isocyanate propyl triethoxysilane in a mass ratio of 1:2:1:0.5 at 120°C for 2 h.

[0061] A preparation method of a dealcoholized single-component transparent silicone sealant, comprising the following steps:

[0062] (1) add the alkoxyl-terminated polydimethylsiloxane and the fumed silica filler in proportion in the planetary machine, start stirring to gradually make the fumed silica filler completely melt into the alkoxyl-terminated polydimethylsiloxane, then add the surface modifier in proportion in the planetary machine, and stir under the condition of nitrogen protection for 30 min;

[0063] (2) add the crosslinking agent in proportion in the planetary machine, continue stirring under the condition of nitrogen protection for 20 min;

[0064] (3) to the planetary machine proportionally add catalyst and adhesion promoter, slowly vacuum stirring 10 min, vacuum to-0.095 MPa after continue stirring reaction 60 min, prepared dealcoholization type single-component transparent silicone sealant.

[0065] Comparative Example 1

[0066] A dealcoholization type single-component transparent silicone sealant, raw materials are composed of the following components in mass fraction:

[0067]

[0068] Among them,

[0069] The crosslinking agent is a mixed crosslinking agent obtained by compounding methyltrimethoxysilane and polymethyltrimethoxysilane in a mass ratio of 1:1.

[0070] The catalyst is a mixed organotin catalyst of dibutyltin dilaurate and dibutyltin diacetate in a mass ratio of 6:4.

[0071] The adhesion promoter is a refluxed product obtained by reacting γ-aminopropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, N-β-(aminoethyl)-aminopropylmethyldimethoxysilane, and γ-isocyanatepropyltriethoxysilane in a mass ratio of 1:2:1:0.5 at 120°C for 2 h.

[0072] A preparation method of a dealcoholization type single-component transparent silicone sealant, comprising the following steps:

[0073] (1) proportionally add alkoxyl-terminated polydimethylsiloxane and fumed silica filler in the planetary machine, start stirring to gradually make the fumed silica filler completely melt into the alkoxyl-terminated polydimethylsiloxane, and stir under nitrogen protection for 30 min;

[0074] (2) proportionally add crosslinking agent into the planetary machine, continue stirring under nitrogen protection for 20 min;

[0075] (3) proportionally add catalyst and adhesion promoter into the planetary machine, slowly vacuum stirring for 10 min, vacuum to-0.095 MPa after continue stirring reaction for 60 min, prepared dealcoholization type single-component transparent silicone sealant.

[0076] Performance detection and result analysis:

[0077] The key properties of the dealcoholization type single-component transparent silicone sealant prepared in Examples 1-3 and Comparative Example 1 were detected, and the results are shown in Table 1.

[0078] Table 1:

[0079]

[0080] From Table 1, it can be seen that the dealcoholized single-component transparent silicone sealant prepared in the embodiment of the application has excellent adhesion to glass, metal, PC, PBT, PET, PVC, ABS and other materials, excellent storage stability and excellent transparency.

[0081] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any change or replacement that can be easily thought of by those skilled in the art within the technical scope disclosed by the present application shall be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A de-alcoholized, one-component, transparent silicone sealant, characterized in that, The silicone sealant comprises, by weight parts: Alkoxy-terminated polydimethylsiloxane: 100 parts; Fumed silica filler: 5~30 parts; Surface modifier: 2-10 parts; Crosslinking agent: 10-30 parts; Catalyst: 0.5~2 parts; Adhesion accelerator: 0.5~2 parts; The surface modifier is a reflux obtained by reacting ethyl acetoacetate diisopropoxyaluminum, ethyl acetoacetate and vinyltrimethoxysilane at 60-80°C for 2-3 hours; the adhesion promoter is a reflux obtained by reacting γ-aminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, N-β-(aminoethyl)-aminopropylmethyldimethoxysilane and γ-isocyanate propyltriethoxysilane at 100-120°C for 2-3 hours.

2. The dealcoholized, single-component, transparent silicone sealant according to claim 1, characterized in that, The mass ratio of ethyl acetoacetate diisopropoxyaluminum, ethyl acetoacetate, and vinyltrimethoxysilane is 1:2:

2.

3. The dealcoholized, single-component, transparent silicone sealant according to claim 1, characterized in that, The mass ratio of γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, N-β-(aminoethyl)-aminopropylmethyldimethoxysilane and γ-isocyanatepropyltriethoxysilane is 1:2:1:0.

5.

4. The dealcoholized, single-component, transparent silicone sealant according to claim 1, characterized in that, The alkoxy-terminated polydimethylsiloxane is α,ω-di(trimethoxysilyl)polydimethylsiloxane, with a viscosity of 50~20000cp at 25°C.

5. The dealcoholized, single-component, transparent silicone sealant according to claim 1, characterized in that, The crosslinking agent is a mixture of methyltrimethoxysilane and polymethyltrimethoxysilane; the mass ratio of methyltrimethoxysilane to polymethyltrimethoxysilane is 1:

1.

6. The dealcoholized, single-component, transparent silicone sealant according to claim 1, characterized in that, The catalyst is a mixed organotin catalyst of dibutyltin dilaurate and dibutyltin diacetate; the mass ratio of dibutyltin dilaurate to dibutyltin diacetate is 6:

4.

7. The method for preparing the dealcoholized one-component transparent silicone sealant according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Add alkoxy-terminated polydimethylsiloxane and fumed silica filler to the planetary machine. Stir to completely integrate the fumed silica filler into the alkoxy-terminated polydimethylsiloxane. Then add a surface modifier to the planetary machine and stir and react for 20-40 minutes under nitrogen protection. S2. Add crosslinking agent into the planetary machine and continue stirring and reacting under nitrogen protection for 20-40 minutes. S3. Add catalyst and adhesion promoter into planetary machine, slowly vacuum and stir for 8~20min. After the vacuum reaches -0.095MPa, continue stirring and reacting for 50~80min to obtain de-alcoholized single-component transparent organosilicon sealant.

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