Polysulfydryl-containing silane as well as preparation method and application thereof

Abstract

The invention provides polysulfydryl-containing alkyl silane as well as a preparation method and application thereof, and relates to the technical field of sulfydryl alkyl silane preparation. The preparation method of the polymercapto-containing alkyl silane comprises the following steps: mixing pentaerythritol tetra (3-mercapto alkyl propionate) and a catalyst under a stirring condition, preheating a mixed solution, dropwise adding isocyanate group-containing silane into the mixed solution, heating, preserving heat and stirring to obtain the polymercapto-containing alkyl silane. The alkyl silane containing multiple sulfydryl groups prepared by the method contains multiple sulfydryl groups, and the preparation method is simple, mild in reaction condition, easy to obtain raw materials, low in cost and suitable for industrial large-scale production. Meanwhile, the reaction process is easy to control, the operation safety is high, the product has no obvious foul smell, and the problem of unpleasant smell commonly accompanied by the traditional sulfydryl alkyl compound is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of mercaptoalkylsilane preparation, in particular to a polymercaptoalkylsilane and a preparation method and application thereof. Background Art

[0002] Mercaptoalkylsilane is an important class of organosilicon compounds, widely used as silane coupling agents, with excellent chemical reactivity and functionalization potential. As a type of silane coupling agent, it plays a bridging role between inorganic materials and organic polymers, and can significantly improve the mechanical properties, weather resistance and interfacial bonding strength of composite materials. In addition, mercaptoalkylsilane also has the ability to undergo addition reactions with unsaturated bonds, which makes it have important application value in the development of photocuring (UV curing) systems, such as for the preparation of new materials such as silicone resins and silicone rubbers, and has a wide range of uses in modifying organic polymers. In the field of polymer materials, mercaptoalkylsilane can participate in a variety of polymerization reactions. In particular, in ultraviolet light curing systems, this type of compound can not only achieve rapid curing through photoinitiation, but also further enhance the adhesion of the material to the substrate through the moisture curing mechanism, giving the material better overall performance.

[0003] Currently, the synthesis methods of mercaptoalkylsilanes mainly include the hydrogen sulfide method, the thiourea method, and the sodium hydrosulfide method. The hydrogen sulfide method is one of the earliest synthesis routes, and is usually formed by the direct reaction of halogenated alkylsilanes with hydrogen sulfide under high temperature and high pressure conditions. However, due to the severe toxicity of hydrogen sulfide and the harsh reaction conditions, its widespread application in industry is limited. The thiourea method is currently a more commonly used method in industry. Its principle is to allow halogenated alkylsilanes to undergo nucleophilic substitution reaction with thiourea, followed by hydrolysis to obtain the target product. Although this method is relatively safe and easy to operate, it has problems such as low yield and the production of foul-smelling guanidine salts as by-products, which affect production efficiency and environmental friendliness. The sodium hydrosulfide method uses chloroalkylsilanes and sodium hydrosulfide as raw materials to synthesize mercaptoalkylsilanes through a condensation reaction. In theory, this method is simple and feasible, but in actual operation it faces environmental problems such as difficulty in reaction control, low yield, and complex wastewater treatment. Furthermore, most mercaptosilane products currently available on the market are monofunctional, such as mercaptopropyltrihexylsilane (MPTS) and mercaptopropyltriethoxysilane (MPTES), which contain only one mercapto group (-SH) per molecule. While these monomercaptosilanes exhibit a certain degree of reactivity, the limited number of functional groups results in low efficiency in cross-linking reactions, making them difficult to meet the high-density cross-linking network requirements of high-performance materials.

[0004] Therefore, there is an urgent need to develop a polythioalkylsilane to improve its crosslinking ability and scope of application. Summary of the Invention

[0005] In view of this, the present invention provides a polythioalkylsilane having mild reaction conditions, simple operation process, high product yield and no unpleasant odor and a preparation method thereof.

[0006] The technical solution of the present invention is achieved as follows:

[0007] In a first aspect, the present invention provides a polythiocarbyl silane having a structural formula as shown in formula (I):

[0008]

[0009] In formula (I), R1 is -CH2 or -C3H6, R2 is -CH3 or -C2H5, and R3 is selected from one of -CH3, -OCH3 or -OC2H5.

[0010] In a second aspect, the present invention relates to a method for preparing the above-mentioned polythiocarbylsilane, comprising the following steps:

[0011] Pentaerythritol tetrakis (3-mercaptoalkyl propionate) and a catalyst are mixed under stirring, the mixed solution is preheated, and then isocyanate-containing silane is added dropwise to the mixed solution, and the mixture is heated and stirred to obtain polymercaptoalkyl silane.

[0012] In one or some possible embodiments, the isocyanate-containing silane is selected from one or more of isocyanatepropyltrimethoxysilane, isocyanatepropyltriethoxysilane, isocyanatepropylmethyldimethoxysilane, isocyanatemethyltrimethoxysilane or isocyanatemethyltriethoxysilane.

[0013] In one or some possible embodiments, the molar ratio of the pentaerythritol tetrakis(3-mercaptoalkylpropionate) to the isocyanate-containing silane is 1:1-2.

[0014] Furthermore, the molar ratio of the pentaerythritol tetrakis (3-mercaptoalkyl propionate) to the isocyanate-containing silane is 1:1.

[0015] In one or some possible embodiments, the catalyst is a basic catalyst; the basic catalyst is selected from triethylamine and / or pyridine.

[0016] In one or some possible embodiments, the amount of the alkaline catalyst used is 0.05 to 0.5% of the total mass of the pentaerythritol tetrakis(3-mercaptoalkylpropionate) and the isocyanate-containing silane.

[0017] Furthermore, the amount of the catalyst used is 0.1 to 0.2% of the total mass of the pentaerythritol tetrakis (3-mercaptoalkyl propionate) and the isocyanate-containing silane.

[0018] In one or some possible embodiments, the conditions for heat preservation and stirring include: a heat preservation temperature of 25 to 100° C. and a time of 0.5 to 4 hours.

[0019] Furthermore, the conditions for heat preservation and stirring include: heat preservation temperature of 30 to 80° C. and time of 0.5 to 2 hours.

[0020] In a third aspect, the present invention relates to the use of the above-mentioned polythiocarbyl silane in a UV curing system.

[0021] The polythiocarbyl-containing silane of the present invention and its preparation method and application have the following beneficial effects compared with the prior art:

[0022] (1) The polythiol-containing silane molecules of the present invention contain multiple thiol groups and have higher reactivity than traditional monothiol silanes. During the polymerization or cross-linking reaction of the material, the compound can provide multiple reaction sites, thereby effectively increasing the cross-linking density and improving the mechanical properties and thermal stability of the material. In addition, the presence of polythiol groups also helps to enhance the interfacial bonding between the material and the substrate, significantly improving adhesion, and enabling it to exhibit more excellent application performance in the fields of coatings, adhesives, composite materials, etc.

[0023] (2) The method of preparing polythiol-containing silanes of the present invention has the advantages of simple process and mild reaction conditions. The raw materials used are readily available and low in cost, making it suitable for large-scale industrial production. Furthermore, the reaction process is easy to control, highly operational, and the product has no noticeable odor, thus overcoming the unpleasant odor often associated with conventional thiol compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is the infrared spectrum of the polythioalkylsilane prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0026] 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 embodiments described 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 making creative efforts are within the scope of protection of the present invention.

[0027] When manufacturing high-performance electronic packaging materials, coatings, adhesives, and other materials, it is often necessary to consider increasing the material's crosslinking density, enhancing physical and mechanical properties, and improving adhesion to various substrates to meet these high demands. Although monomercaptosilane exhibits good performance in certain applications, its ability to participate in crosslinking reactions is limited due to the presence of only one mercapto group per molecule. This limits its effectiveness in applications requiring a high-density crosslinked network.

[0028] Therefore, the inventors prepared a new substance - polythiocarbyl silane through further exploration and research.

[0029] The polythiocarbyl-containing silane prepared by the present invention can significantly improve the polymerization reaction efficiency of unsaturated polymers under ultraviolet light (UV) conditions. Under normal circumstances, unsaturated polymer materials will undergo photopolymerization reaction after being irradiated with ultraviolet light under the action of a photoinitiator. However, due to the inhibition of oxygen and the gel effect that occurs in the system during the reaction, the polymerization reaction is difficult to continue, and the final conversion rate of double bonds is low. By introducing a polythiocarbyl-containing silane compound into the system, the present invention can not only effectively eliminate the influence of oxygen inhibition, but also transform the photopolymerization reaction from a traditional chain growth mechanism to a step-by-step growth mechanism, thereby delaying the appearance of the gel point and significantly improving the final conversion rate of the double bonds. At the same time, the alkoxy part in the silane compound can undergo hydrolysis and polycondensation reaction, realizing the dual functions of ultraviolet curing and moisture curing, and therefore shows a wide range of application prospects in multiple fields.

[0030] The present invention will be further described below with reference to specific examples, but the scope of protection of the present invention is not limited by the following examples. Unless otherwise specified, the materials mainly involved in the following examples are conventional commercial products.

[0031] Pentaerythritol tetrakis(3-mercaptoalkylpropionate), polythiol 405B, Shandong Yifeng New Materials Co., Ltd.

[0032] Example 1

[0033] This embodiment provides a method for preparing polythioalkylsilane, comprising the following steps:

[0034] Under stirring conditions, 244.33 g of pentaerythritol tetrakis (3-mercaptoalkyl propionate) and 0.35 g of triethylamine were mixed and preheated to 25° C., and 102.64 g of isocyanate propyl trimethoxysilane was slowly added dropwise to the mixture over 2 hours. The mixture was heated to 70° C. and stirred for 1 hour to obtain 346.97 g of tris (3-mercaptoalkyl propionate) pentaerythritol propionate thioamidopropyl trimethoxysilane. The content was determined to be 92% by liquid chromatography.

[0035] The reaction solution was tested by infrared spectroscopy, such as Figure 1 It was found that the reaction solution did not contain isocyanatepropyltrimethoxysilane.

[0036] The reaction equation involved in this embodiment is as follows:

[0037]

[0038] Example 2

[0039] This embodiment provides a method for preparing polythioalkylsilane, comprising the following steps:

[0040] Under stirring conditions, 244.33 g of pentaerythritol tetrakis (3-mercaptopropionate) and 0.45 g of triethylamine were mixed and preheated to 30° C., and 205.28 g of isocyanatepropyltrimethoxysilane was slowly added dropwise to the mixture. The addition was completed over 2 hours, and the mixture was heated to 80° C. and stirred for 1 hour to obtain 449.61 g of di(3-mercaptopropionate)pentaerythritol di(propionatethioamidopropyltrimethoxysilane). The content was 91.5% as determined by liquid chromatography.

[0041] Example 3

[0042] This embodiment provides a method for preparing polythioalkylsilane, comprising the following steps:

[0043] Under stirring conditions, 244.33 g of pentaerythritol tetrakis (3-mercaptoalkyl propionate) and 0.45 g of pyridine were mixed, condensed and refluxed, and preheated to 30° C., and 123.68 g of isocyanatepropyltriethoxysilane was slowly added dropwise to the mixture. The addition was completed over 2 hours, and the mixture was heated to 80° C. and stirred for 1 hour to obtain 368.01 g of tris (3-mercaptoalkyl propionate) pentaerythritol propionate-thioamidopropyltriethoxysilane. The content was determined to be 90.8% by liquid chromatography.

[0044] Example 4

[0045] This embodiment provides a method for preparing polythioalkylsilane, comprising the following steps:

[0046] Under stirring conditions, 244.33 g of pentaerythritol tetrakis (3-mercaptoalkyl propionate) and 0.33 g of triethylamine were mixed, condensed and refluxed, and preheated to 30° C., and then 88.62 g of isocyanate methyl trimethoxysilane was slowly added dropwise to the mixture. The addition was completed over 2 hours, and the mixture was heated to 80° C. and stirred for 1 hour to obtain 333.28 g of tris (3-mercaptoalkyl propionate) pentaerythritol propionate thioamidomethyl trimethoxysilane. The content was determined to be 91.5% by liquid chromatography.

[0047] Taking tris(3-mercaptopropionate) pentaerythritol propionate-thioamidopropyltrimethoxysilane prepared in Example 1 as an example, different mass contents of the polymercaptosilane prepared in Example 1 were added to a conformal coating and further applied to the preparation of functional coatings for UV black adhesives in the field of flat-panel displays, specifically OLED and Micro-LED devices. The substrates used were cleaned ordinary glass, ITO conductive glass, and a titanium / aluminum / titanium (Ti / Al / Ti) composite metal layer structure, and their performance was evaluated. The basic formula and content of the conformal coating are shown in Table 1, and the performance test results are shown in Table 2.

[0048] Table 1 Basic formula and content of conformal coating

[0049]

[0050] Table 2 Performance test results

[0051]

[0052] The performance test results in Table 2 show that after adding 0.1% to 0.5% of polythiosilane to the free radical curing UV / moisture dual curing UV conformal paint, the 100-grid adhesion is significantly improved. When the addition amount is 0.50, the 100-grid adhesion is improved to 100-grid level 0, which is the best adhesion.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A polythiocarbyl silane, characterized in that: Its structural formula is shown in formula (I): In formula (I), R1 is -CH2 or -C3H6, R2 is -CH3 or -C2H5, and R3 is selected from one of -CH3, -OCH3 or -OC2H5.

2. A method for preparing the polythiocarbylsilane according to claim 1, characterized in that: The following steps are involved: Pentaerythritol tetrakis (3-mercaptoalkyl propionate) and a catalyst are mixed under stirring, the mixed solution is preheated, and then isocyanate-containing silane is added dropwise to the mixed solution, and the mixture is heated and stirred to obtain polymercaptoalkyl silane.

3. The method for preparing polythioalkylsilane according to claim 2, wherein: The isocyanate-containing silane is selected from one or more of isocyanate propyltrimethoxysilane, isocyanate propyltriethoxysilane, isocyanate propylmethyldimethoxysilane, isocyanate methyltrimethoxysilane and isocyanate methyltriethoxysilane.

4. The method for preparing polythiocarbylsilane according to claim 3, wherein: The molar ratio of the pentaerythritol tetrakis (3-mercaptoalkyl propionate) to the isocyanate-containing silane is 1:1-2.

5. The method for preparing polythioalkylsilane according to claim 2, wherein: The catalyst is a basic catalyst; the basic catalyst is selected from triethylamine and / or pyridine.

6. The method for preparing polythioalkylsilane according to claim 5, wherein: The amount of the alkaline catalyst used is 0.05-0.5% of the total mass of the pentaerythritol tetrakis (3-mercaptoalkyl propionate) and the isocyanate-containing silane.

7. The method for preparing polythioalkylsilane according to claim 6, wherein: The amount of the catalyst used is 0.1-0.2% of the total mass of the pentaerythritol tetrakis (3-mercaptoalkyl propionate) and the isocyanate-containing silane.

8. The method for preparing polythioalkylsilane according to claim 2, wherein: The conditions for heat preservation and stirring include: heat preservation temperature of 25 to 100° C. and time of 0.5 to 4 hours.

9. The method for preparing polythioalkylsilane according to claim 8, wherein: The conditions for heat preservation and stirring include: heat preservation temperature of 30 to 80° C. and time of 0.5 to 2 hours.

10. Use of the polythiocarbyl silane according to claim 1 in a UV curing system.

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