Isocyanate modified silane coupling agent and preparation method thereof

Abstract

The invention discloses an isocyanate-modified silane coupling agent and a preparation method thereof, the isocyanate-modified silane coupling agent satisfies the following conditions (1) and (2) when stored at 40 DEG C for 80 days: (1) in the stored isocyanate-modified silane coupling agent, the increase of the content of an isocyanate polymer is less than 0.5 wt%; and (2) the color number of the stored isocyanate-modified silane coupling agent is increased by not more than 20% of the initial color number of the isocyanate-modified silane coupling agent. Under the condition that the isoisocyanate modified silane coupling agent is stored at 40 DEG C for 80 days, the content stability and color number stability of the isocyanate polymer are also obviously improved, and the stability of the product can be further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of silane coupling agent modification, and in particular relates to a storage-stable isocyanate-modified silane coupling agent and a preparation method thereof. Background Art

[0002] Isocyanate-modified silane coupling agent is a functional organosilicon compound that has the properties of aliphatic isocyanate and silane coupling agent. It is generally added to organic materials to improve their chemical resistance, thermal stability and mechanical properties. It can be used as a raw material for coatings and adhesives in various industrial products, especially in adhesives.

[0003] As is well known, patent application DE 3524215A mentions that an isocyanate-modified silane coupling agent can be obtained by reacting a chlorine-modified silane coupling agent with a cyanate, without using highly toxic chemicals such as phosgene, with a simple process route and low investment cost. This process route is simple and has low cost. CN 110437273A proposes a method for preparing 3-isocyanate propyltriethoxysilane based on ionic liquid, using ionic liquid as a solvent, which can improve the phenomenon of poor solubility of the reaction raw materials and low yield. Since catalysts, additives, etc. are inevitably added during the reaction process, other metal ions and Lewis acid groups will enter, which are difficult to effectively remove in the post-processing and separation process, which will affect the final stability of the product, resulting in quality problems such as increased polymer content and improved color number of the final product.

[0004] Therefore, there is an urgent need in the art to provide a method that can improve the stability of products during long-term storage. Summary of the invention

[0005] The object of the present invention is to provide a storage-stable isocyanate-modified silane coupling agent (TSPI) and a preparation method thereof, wherein the reaction solution is pretreated by a heat treatment process, and the stability of the polymer content and the color number stability of the final product after the treatment are significantly improved when stored at 40°C for 80 days.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A storage-stable isocyanate-modified silane coupling agent, which satisfies the following conditions ① and ② when stored at 40° C. for 80 days:

[0008] ① The increase in the content of isocyanate polymer in the isocyanate-modified silane coupling agent after storage is less than 0.5wt%;

[0009] ② After storage, the color number of the isocyanate-modified silane coupling agent shall not increase by more than 20% of its initial color number.

[0010] According to the preparation method provided by the present invention, in some embodiments, when the isocyanate-modified silane coupling agent composition is stored at 40° C. for 80 days, the color number increase does not exceed 20% of its initial color number (for example, the color number increase is 18%, 14%, 10%, 6%, 4%, 2%, 1%, 0.5% of its initial color number).

[0011] The color number increase mentioned herein may refer to the percentage of the absolute value of the change difference between the product color number measured at 40° C. for 80 days and its initial color number to its initial color number. The initial color number mentioned here may refer to the product color number before storage.

[0012] In some embodiments, the increase in the polymer content of the isocyanate-modified silane coupling agent is less than or equal to 0.8 wt % when stored at 40° C. for 80 days. The “increase in polymer content” or “increase in isocyanate polymer content” mentioned herein refers to the absolute difference in the isocyanate polymer content in the isocyanate-modified silane coupling agent before and after storage under the storage conditions described above.

[0013] Preferably, the structural formula of the isocyanate-modified silane coupling agent is shown in formula (I):

[0014]

[0015] In formula (I), R2, R3, and R4 are the same or different, and are independently saturated alkyl and / or saturated alkoxy groups, and at least one of R2, R3, and R4 is a saturated alkoxy group (for example, R2 is a saturated alkoxy group, or R3 is a saturated alkoxy group, or R4 is a saturated alkoxy group, or R2 and R3 are both saturated alkoxy groups, or R2 and R3 are both saturated alkoxy groups); preferably, the saturated alkyl group is a saturated alkyl group of C1 to C6; the general formula of the saturated alkoxy group is R5O—, in which R5 is preferably a saturated alkyl group of C1 to C6;

[0016] R1 is a branched or straight-chain alkylene or cycloalkylene, arylene or aralkylene, preferably the branched or straight-chain alkylene or cycloalkylene contains 1-12 carbon atoms, preferably the arylene contains 6-10 carbon atoms, preferably the aralkylene contains 7-10 carbon atoms, and R1 is more preferably a branched or straight-chain alkylene containing 1-6 carbon atoms.

[0017] In the present invention, the C1-C6 saturated alkyl group may be, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, or an n-pentyl group.

[0018] The branched or straight chain alkylene or cycloalkylene group containing 1 to 12 carbon atoms may be, for example, methylene, ethylene, n-propylene, isopropylene, n-butylene, n-pentylene, hexylene, heptylene, octylene. The aralkylene group containing 7 to 10 carbon atoms may be, for example, methylenephenyl, ethylenephenyl.

[0019] In some examples, the isocyanate polymer includes one or more of an isocyanurate structure, a carbamate structure, an allophanate structure, a biuret structure, an iminooxadiazinedione structure, a uretdione structure, a carbodiimide structure, and a uretonimine structure.

[0020] In some preferred examples, the isocyanate polymer is a trimer polyisocyanate, a biuret polyisocyanate or a uretdione polyisocyanate.

[0021] For example, the trimer polyisocyanate may include one or more of an isocyanurate structure, a carbamate structure, an allophanate structure, an iminooxadiazinedione structure, a uretdione structure, a carbodiimide structure, and a uretonimine structure.

[0022] For example, the biuret polyisocyanate may include one or more of a biuret structure, a carbodiimide structure, a uretdione structure, and a uretonimine structure.

[0023] For example, the uretdione polyisocyanate may include one or more of a uretdione structure, an isocyanurate structure, a carbamate structure, an allophanate structure, an iminooxadiazinedione structure, a carbodiimide structure, and a uretonimine structure.

[0024] The present invention also provides a method for preparing the isocyanate-modified silane coupling agent, comprising: in the presence of a catalyst system, using a chlorine-modified silane coupling agent to react with a solid cyanate to obtain an isocyanate reaction liquid; performing solid-liquid separation on the solid raw materials and by-product chloride salts remaining in the obtained isocyanate reaction liquid to obtain a filtrate; heat-treating the obtained filtrate to obtain the heat-treated isocyanate-modified silane coupling agent; and separating the heat-treated reaction liquid to obtain the isocyanate-modified silane coupling agent.

[0025] The heat treatment temperature is 5-10°C higher than the color-sensitive temperature of the obtained isocyanate-modified silane coupling agent, and the heat treatment time is 15-45min;

[0026] The "reaching a suitable conversion rate" mentioned here can be understood as a conversion rate pre-set according to the product to be produced. Different types of isocyanate-modified silane coupling agent products have different conversion rates to be achieved, which can be converted and reflected by controlling the residual amount of raw materials in the reaction system; this is well known to those skilled in the art and will not be elaborated in this article.

[0027] The color-sensitive temperature of isocyanate-modified silane coupling agent mentioned in this article can be understood as follows: the isocyanate-modified silane coupling agent product is heated at 100-200°C, and the temperature range of heating is divided into multiple isothermal intervals and the color number of the heated product is tested at this temperature interval; that is, within the temperature range of 100-200°C, a point can be selected every 5°C and heated for 2 hours, and the product color number corresponding to the temperature point is tested, and then the measured color number points and the corresponding temperature points are plotted into a color number-temperature curve. In the resulting curve, the temperature corresponding to the increase of the product color number by 1.5 times is the sensitive temperature at which the color number is prone to drastic changes, referred to as the color-sensitive temperature.

[0028] Different types of isocyanate-modified silane coupling agent products may have different corresponding color-sensitive temperatures.

[0029] In some examples, the isocyanate-modified silane coupling agent having an ethoxy group has a color-sensitive temperature of 155-170° C. (eg, 157° C., 160° C., 163° C., 168° C.).

[0030] In some examples, the isocyanate-modified silane coupling agent having a methoxy group has a color-sensitive temperature of 140-155° C. (eg, 142° C., 146° C., 148° C., 152° C.).

[0031] The reaction liquid is first heat treated before entering the separation device for separation treatment, and then the isocyanate monomers that do not participate in the reaction in the system are separated, and the storage stability of the final product (especially the color number stability and the stability of the polymer) is greatly improved. The inventor found based on a large number of embodiments that if the reaction liquid is heat treated under high temperature conditions higher than the color-sensitive temperature of the product, the active groups present in the system, such as water, catalyst residues, chlorine, and metal elements, can be preferentially destroyed. If directly separated without heat treatment, on the one hand, these components will enter the product, thereby promoting the polymerization of the product during long-term storage, increasing the color number, and thus affecting the downstream application performance. On the other hand, these components may be destroyed during the distillation process, but will affect the ability of distillation and / or treatment, increase the cost of treatment, and increase the risk of product degradation. After heat treatment, the active components in the separated product are less, making the separation capacity of the distillation tower more stable, which can make the molecular weight composition of the final product change less, and then make the color number change very little, and will not have an adverse effect on the downstream application performance.

[0032] The temperature needs to be controlled during the heat treatment step. If the heat treatment temperature is too high, the color and viscosity of the product will change greatly; if the heat treatment temperature is too low, it will not improve the stability. Therefore, based on the color-sensitive temperature of the product, the appropriate heat treatment temperature is selected to ensure the ideal treatment effect. If the heat treatment time is too long, the color and viscosity of the product will change greatly; if the heat treatment time is too short, it will also not improve the stability.

[0033] In the synthesis process of the isocyanate-modified silane coupling agent, the structural formula of the raw material chlorine-modified silane coupling agent is shown in formula (III):

[0034]

[0035] In formula (II), R2, R3, and R4 are the same or different, and are independently saturated alkyl and / or saturated alkoxy groups, and at least one of R2, R3, and R4 is a saturated alkoxy group; preferably, the saturated alkyl group is a saturated alkyl group of C1 to C6; the general formula of the saturated alkoxy group is R5O—, in which R5 is preferably a saturated alkyl group of C1 to C6;

[0036] R1 is a branched or straight-chain alkylene or cycloalkylene, arylene or aralkylene, preferably the branched or straight-chain alkylene or cycloalkylene contains 1-12 carbon atoms, preferably the arylene contains 6-10 carbon atoms, preferably the aralkylene contains 7-10 carbon atoms, and R1 is more preferably a branched or straight-chain alkylene containing 1-6 carbon atoms.

[0037] Preferably, the process of synthesizing the isocyanate-modified silane coupling agent using the chlorine-modified silane coupling agent in the presence of the catalyst system of the present invention can be understood as firstly contacting the chlorine-modified silane coupling agent TSPC represented by formula (II) with a cyanate raw material and reacting in the presence of a catalyst to obtain the isocyanate-modified silane coupling agent (TSPI) represented by formula (I), and the reaction formula is as follows:

[0038]

[0039] In some embodiments, the cyanate raw material is selected from one or more alkaline metal cyanates, and the alkaline metal can be selected from alkali metals such as Ca, K, Na, Mg and / or alkaline earth metals.

[0040] In some embodiments, in the reaction step, the molar amount of the cyanate raw material is 0.9-4.0 times (eg, 1 times, 1.5 times, 2.5 times, 3 times, 4 times) of the chlorine-modified silane coupling agent, preferably 1.0-2.0 times.

[0041] The catalyst is selected from one or more of chain polyethylene glycol, chain polyethylene glycol dialkyl ether, cyclic crown ether, quaternary ammonium salt, tertiary amine, quaternary ammonium base, quaternary phosphonium salt, and metal chloride, preferably one or more of tetrabutylammonium bromide, tetrabutylammonium chloride, 18-crown ether, zinc chloride, and pyridine.

[0042] Isocyanate groups are generated during the reaction. Isocyanate groups are at risk of polymerization at high temperatures, and lower temperatures require longer reaction times. Therefore, the reaction temperature needs to be within an appropriate range to avoid self-polymerization of isocyanate groups. At the same time, in the presence of a phase transfer catalyst, a lower temperature can meet the reaction requirements. On the other hand, too much catalyst will promote the self-polymerization of isocyanate. At the same time, too much catalyst may cause the system to terminate, which is not conducive to the subsequent separation step. Therefore, the amount of catalyst used should be coordinated with the reaction temperature to increase the reaction rate while ensuring the product yield.

[0043] In some embodiments, the molar amount of the catalyst is 0.001-0.05 times (eg, 0.001 times, 0.005 times, 0.01 times, 0.02 times, 0.04 times) of the chlorine-modified silane coupling agent, preferably 0.005-0.01 times.

[0044] The reaction temperature of the reaction is 60 to 130°C, for example, 40°C, 60°C, 80°C, 100°C), preferably 85 to 105°C.

[0045] In the corresponding reaction step, an inert organic solvent may be optionally used to dilute the reaction system to reduce the polymerization reactivity of the raw materials. The inert organic solvent may be selected from aromatic hydrocarbons, halogenated aromatic hydrocarbons, halogenated aliphatic hydrocarbons, aliphatic ester compounds or aromatic ester compounds, aliphatic hydrocarbons or aromatic hydrocarbon organic solvents.

[0046] After the reaction is complete, the solids and / or salts are separated by filtration or centrifugation, preferably by filtration or centrifugation of the product stream from the phase transfer to separate the solids, preferably at 30-100° C., more preferably at 50-80° C. The filtration can be carried out through a membrane, an adsorber / adsorbent or a fiber pad, by vacuum filtration or pressure filtration.

[0047] If a solvent is used, the inert organic solvent is recovered by distilling the inactive solvent from the reaction solution using a known distillation tower after the solid phase separation step. It is worth noting that the recovery of the inert solvent is generally carried out under reduced pressure, such as a pressure of 0.3 kPa or more, preferably 0.45 kPa or more, such as 50 kPa or less, preferably 30 kPa or less. Under preferred pressure conditions, the preferred boiling point of the inert solvent is 60 to 120 ° C. If a solvent with a higher boiling point is used, it will lead to difficulty in separation, increase energy consumption, and affect the purity of the final product.

[0048] The purification treatment is vacuum distillation and / or rectification.

[0049] When purification is performed by distillation, the distillation tower may be a plate tower or a packed tower. Specifically, the number of theoretical plates of the distillation tower (packed tower) is, for example, 2 or more, preferably 5 or more, for example, 60 or less, preferably 40 or less. In addition, the top pressure of the distillation tower is, for example, 0.1 kPa or more, preferably 0.15 kPa or more, for example, 4 kPa or less, preferably 2.5 kPa or less. In addition, the top reflux ratio of the distillation tower is, for example, 0.01 or more, preferably 0.1 or more, for example, 60 or less, preferably 40 or less.

[0050] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0051] (1) In the present invention, the stability of the cyanate-modified silane coupling agent obtained by the invention is greatly improved. When stored at 40° C. for 80 days, the color number increase does not exceed 20% of its initial color number, and the change range of the polymer content is also very small.

[0052] (2) The method provided by the present invention does not use highly toxic chemicals, has mild reaction conditions, and all solvents can be recycled, which meets environmental protection requirements; conventional equipment is used for combination, the equipment is simple, and it is easy to realize industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is the color-sensitive temperature curve of TMSPI. DETAILED DESCRIPTION

[0054] In order to understand the technical features and contents of the present invention in detail, the preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described in the embodiments, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described here.

[0055] Where specific experimental steps or conditions are not specified in the examples, the corresponding conventional experimental steps or conditions in the art can be used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be purchased commercially.

[0056] Sources of materials and explanations of abbreviations involved

[0057] 3-Chloropropyltrimethoxysilane (TMSPC), Inokane;

[0058] 3-Chloropropylmethyldiethoxysilane (DESPC), Inokite;

[0059] 3-Chloropropyltriethoxysilane (TESPC), Inokite;

[0060] 3-isocyanatepropyltrimethoxysilane (TMSPI), Tangshan Sanfu New Materials;

[0061] 3-isocyanatepropylmethyldiethoxysilane (DESPI), Tangshan Sanfu New Materials;

[0062] 3-isocyanatepropyltriethoxysilane (TESPI), Tangshan Sanfu New Materials;

[0063] Product color sensitivity temperature and test method

[0064] Heat TMSPI at 100-200℃ for 2h at 5℃ intervals, and test the product color number corresponding to the point, and then plot the measured color number points and the corresponding temperature points into a color number-temperature curve. In the obtained curve, the temperature corresponding to the product color number increasing by 1.5 times is defined as the sensitive temperature at which the color number is prone to drastic changes, which is referred to as the color sensitive temperature. The color sensitive temperature of TMSPI is 140℃.

[0065] The color sensitivity temperature of DESPI is 150℃ and the color sensitivity temperature of TESPI is 155℃.

[0066] TSPI products can be qualitatively and quantitatively analyzed by liquid chromatography; instrument: Agilent 1260; chromatographic column: Agilent Extend C18 RRHD 2.1×100mm 1.8μm; column temperature: 40℃; flow rate: 0.2ml / min; mobile phase: A: pure water, B: pure acetonitrile; injection volume: 20μL; detection wavelength: 210nm.

[0067] Product viscosity determination method: Dynamic mechanical viscosity was determined using a BrookField DV-IPrime viscometer with an S21 rotor at 25°C;

[0068] Product color number determination method: Based on the method of GB / T 3143-1982, the color number is measured in a 50mm disposable rectangular cuvette using LICO400 from HACH Lange.

[0069] Example 1

[0070] The preparation method of an isocyanate-modified silane coupling agent comprises the following steps:

[0071] (A) Reaction process

[0072] Use a 500ml glass reactor as a phase transfer reactor, prepare 120g of pretreated 3-chloropropyltrimethoxysilane (TMSPC), first place 60g of TMSPC in the phase transfer reactor, add 0.97g of tetrabutylammonium bromide catalyst and 41.5g of sodium cyanate, and then heat to 80°C. Then add the remaining 60g of TMSPC at 5ml / min through a peristaltic pump, and react for 120min under normal pressure. Obtain a reaction solution containing TMSPI product. The reaction formula is as follows:

[0073]

[0074] (B) Solid-Liquid and Distillation Separation Process

[0075] The reaction solution obtained by the phase transfer reaction is filtered under reduced pressure to remove the solid salt insoluble in the system.

[0076] (C) Heat treatment process

[0077] The reaction solution was heat-treated at 148° C. for 20 min to obtain a heat-treated reaction solution.

[0078] (D) Distillation process

[0079] The material flow entering the distillation process is separated by a Weiss distillation column at a pressure of 100 Pa and a bottom temperature of 130° C. to separate the products. The distillate is distilled to obtain a TMSPI product with a content of 98.9% and a yield of 92.3%. The finished product is a colorless liquid.

[0080] The prepared TMSPI product was tested and found to have a chromaticity of 15 Hazen and a polymer content of 0.17 wt %.

[0081] After the prepared isocyanate-modified silane coupling agent was placed at 40° C. for 80 days, its chromaticity was measured to be 17 Hazen and its polymer content was 0.22 wt %.

[0082] By comparison, the absolute value of the color change difference of the product before and after storage is 2 Hazen. The absolute value of the polymer content change difference of the product before and after storage is 0.05 wt %. This shows that the stability of the product before and after storage is greatly improved.

[0083] Example 2

[0084] The preparation method of an isocyanate-modified silane coupling agent comprises the following steps:

[0085] (A) Reaction process

[0086] A 500 ml glass reactor was used as a phase transfer reactor, 120 g of pretreated 3-chloropropyltriethoxysilane (TESPC) was prepared, 60 g of TESPC was placed in the phase transfer reactor, 0.82 g of tetrabutylammonium bromide catalyst and 41.5 g of sodium cyanate were added, and then the temperature was raised to 100 ° C. The remaining 60 g of TMSPC was added at 5 ml / min through a peristaltic pump, and the reaction was carried out for 150 min under normal pressure.

[0087] A reaction solution containing TESPI product is obtained. The reaction formula is as follows:

[0088] (B) Solid-Liquid and Distillation Separation Process The reaction solution obtained by the phase transfer reaction was filtered under reduced pressure to remove the solid salt insoluble in the system.

[0089] (C) Heat treatment process

[0090] The reaction solution was heat-treated at 163° C. for 15 min to obtain a heat-treated reaction solution.

[0091] (D) Distillation process

[0092] The material flow entering the distillation process is separated by a Weiss distillation column at a pressure of 100 Pa and a bottom temperature of 140° C. to separate the products. The distillate is distilled to obtain a TMSPI product with a content of 99.1% and a yield of 93.5%. The finished product is a colorless liquid.

[0093] The prepared TESPI product was tested and found to have a chromaticity of 13 Hazen and a polymer content of 0.23 wt %.

[0094] After the prepared isocyanate-modified silane coupling agent was placed at 40° C. for 80 days, its chromaticity was measured to be 16 Hazen and its polymer content was 0.27 wt %.

[0095] By comparison, the absolute value of the color change difference of the product before and after storage is 3 Hazen. The absolute value of the polymer content change difference of the product before and after storage is 0.05 wt %. This shows that the stability of the product before and after storage is greatly improved.

[0096] Example 3

[0097] The preparation method of an isocyanate-modified silane coupling agent comprises the following steps:

[0098] (A) Reaction process

[0099] Use a 500ml glass reactor as a phase transfer reactor, prepare 160g of pretreated 3-chloropropyldiethoxymethylsilane (DESPC), first place 80g of DESPC in the phase transfer reactor, add 1.09g of tetrabutylammonium bromide catalyst and 53.9g of sodium cyanate, and then heat to 90°C. Then add the remaining 80g of TMSPC at 5ml / min through a peristaltic pump, and react for 130min under normal pressure. Obtain a reaction solution containing DESPI product. The reaction formula is as follows:

[0100]

[0101] (B) Solid-Liquid and Distillation Separation Process

[0102] The reaction solution obtained by the phase transfer reaction is filtered under reduced pressure to remove the solid salt insoluble in the system.

[0103] (C) Heat treatment process

[0104] The reaction solution was heat-treated at 158° C. for 10 min to obtain a heat-treated reaction solution.

[0105] (D) Distillation process

[0106] The material flow entering the distillation process is separated by a Weiss distillation column at a pressure of 100 Pa and a bottom temperature of 135° C. The product is separated and the distillate is distilled to obtain a DESPI product with a content of 98.3% and a yield of 91.5%. The finished product is a colorless liquid.

[0107] The prepared DESPI product was tested and found to have a chromaticity of 11 Hazen and a polymer content of 0.32 wt%.

[0108] After the prepared isocyanate-modified silane coupling agent was placed at 40° C. for 80 days, its chromaticity was measured to be 14 Hazen and its polymer content was 0.43 wt %.

[0109] By comparison, the absolute value of the color change difference of the product before and after storage is 3 Hazen. The absolute value of the polymer content change difference of the product before and after storage is 0.11 wt %. This shows that the stability of the product before and after storage is greatly improved.

[0110] Example 4

[0111] Use a 1000ml glass reactor as a phase transfer reactor, prepare 120g of pretreated 3-chloropropyltrimethoxysilane (TMSPC), add 480g of dimethyl sulfoxide (DMSO) and place it in the phase transfer reactor, add 0.97g of tetrabutylammonium bromide catalyst and 41.5g of sodium cyanate, and then heat it to 80°C. Then add 120g of TMSPC at 5ml / min through a peristaltic pump, and react for 120min under normal pressure. Obtain a reaction solution containing TMSPI product. The reaction formula is as follows:

[0112]

[0113] (B) Solid-Liquid and Distillation Separation Process

[0114] The reaction solution obtained by the phase transfer reaction was filtered under reduced pressure to remove the solid salt insoluble in the system. The reaction solvent DMSO was separated at a pressure of 300 Pa and a temperature of 80°C.

[0115] (C) Heat treatment process

[0116] The reaction solution was heat-treated at 145° C. for 10 min to obtain a heat-treated reaction solution.

[0117] (D) Distillation process

[0118] The material flow entering the distillation process is separated by a Weiss distillation column at a pressure of 100 Pa and a bottom temperature of 130° C. to separate the products. The distillate is distilled to obtain a TMSPI product with a content of 98.8% and a yield of 92.6%. The finished product is a colorless liquid.

[0119] The prepared TMSPI product was tested and found to have a chromaticity of 16 Hazen and a polymer content of 0.18 wt %.

[0120] After the prepared isocyanate-modified silane coupling agent was placed at 40° C. for 80 days, its chromaticity was measured to be 19 Hazen and its polymer content was 0.25 wt %.

[0121] By comparison, the absolute value of the color change difference of the product before and after storage is 3 Hazen. The absolute value of the polymer content change difference of the product before and after storage is 0.07 wt %. This shows that the stability of the product before and after storage is greatly improved.

[0122] Example 5

[0123] Use a 500ml glass reactor as a phase transfer reactor, prepare 180g of pretreated 3-chloropropyltrimethoxysilane (TMSPC), add 60g of TMSPC and place it in the phase transfer reactor, add 0.97g of tetrabutylammonium bromide catalyst and 41.5g of sodium cyanate, and then heat it to 80°C. Then add 120g of TMSPC at 5ml / min through a peristaltic pump, and react for 120min under normal pressure. Get a reaction solution containing TMSPI product. The reaction formula is as follows:

[0124]

[0125] (B) Solid-Liquid and Distillation Separation Process

[0126] The reaction liquid obtained by the phase transfer reaction was filtered under reduced pressure to remove the solid salts that were insoluble in the system. The reaction solvent DMSO was separated at a pressure of 300 Pa and a temperature of 80°C.

[0127] (C) Heat treatment process

[0128] The reaction solution was heat-treated at 150° C. for 15 minutes to obtain a heat-treated reaction solution.

[0129] (D) Distillation process

[0130] The material flow entering the distillation process is separated by a Weiss distillation column at a pressure of 100 Pa and a bottom temperature of 130° C. to separate the products. The distillate is distilled to obtain a TMSPI product with a content of 99.0% and a yield of 92.3%. The finished product is a colorless liquid.

[0131] The prepared TMSPI product was tested and found to have a chromaticity of 14 Hazen and a polymer content of 0.15 wt%.

[0132] After the prepared isocyanate-modified silane coupling agent was placed at 40° C. for 80 days, its chromaticity was measured to be 16 Hazen and its polymer content was 0.22 wt %.

[0133] By comparison, the absolute value of the color change difference of the product before and after storage is 2 Hazen. The absolute value of the polymer content change difference of the product before and after storage is 0.07 wt %. This shows that the stability of the product before and after storage is greatly improved.

[0134] Comparative Example 1

[0135] The operating steps are similar to those of Example 1, except that step (C) is heat treated at 165°C for 20 min.

[0136] The prepared isocyanate-modified silane coupling agent was tested and found to have a chromaticity of 21 Hazen and a polymer content of 0.21 wt %.

[0137] After the prepared isocyanate-modified silane coupling agent was placed at 40° C. for 80 days, its chromaticity was measured to be 28 Hazen and its polymer content was 0.65 wt %.

[0138] The absolute value of the color change difference of the product before and after storage is 7 Hazen. The absolute value of the polymer change difference of the product before and after storage is 0.44 wt %. This shows that the stability improvement of the product before and after storage is not as significant as that of the corresponding embodiment.

[0139] Comparative Example 2

[0140] The operating steps are similar to those of Example 1, except that step (C) is heat treated at 138°C for 20 min.

[0141] The prepared isocyanate-modified silane coupling agent was tested and found to have a chromaticity of 18 Hazen and a polymer content of 0.20 wt %.

[0142] After the prepared isocyanate-modified silane coupling agent was placed at 40° C. for 80 days, its chromaticity was measured to be 26 Hazen and its polymer content was 0.56 wt %.

[0143] The absolute value of the color change difference of the product before and after storage is 7 Hazen. The absolute value of the polymer change difference of the product before and after storage is 0.36 wt %. This shows that the stability improvement of the product before and after storage is not as significant as that of the corresponding embodiment.

[0144] Comparative Example 3

[0145] The operating steps are as described in Example 2, except that step (C) is heat treated at 165°C for 50 min.

[0146] The prepared isocyanate-modified silane coupling agent was tested and found to have a chromaticity of 19 Hazen and a polymer content of 0.21 wt %.

[0147] After the prepared isocyanate-modified silane coupling agent was placed at 40° C. for 80 days, its chromaticity was measured to be 31 Hazen and its polymer content was 0.59 wt %.

[0148] The absolute value of the color change difference of the product before and after storage is 12 Hazen. The absolute value of the polymer change difference of the product before and after storage is 0.37 wt %. This shows that the stability improvement of the product before and after storage is not as significant as that of the corresponding embodiment.

[0149] Comparative Example 4

[0150] The operating steps are similar to those of Example 2, except that step (C) is heat treated at 165°C for 5 minutes.

[0151] The prepared isocyanate-modified silane coupling agent was tested and found to have a chromaticity of 19 Hazen and a polymer content of 0.20 wt %.

[0152] After the prepared isocyanate-modified silane coupling agent was placed at 40° C. for 80 days, its chromaticity was measured to be 30 Hazen and its polymer content was 0.52 wt %.

[0153] The absolute value of the color change difference of the product before and after storage is 11 Hazen. The absolute value of the polymer change difference of the product before and after storage is 0.32 wt %. This shows that the stability improvement of the product before and after storage is not as significant as that of the corresponding embodiment.

[0154] By the method of the present invention, the storage stability (e.g., change in polymer content, change in color number) is greatly improved. For example, for isocyanate-modified silane coupling agent products, in some preferred embodiments, after being placed at 40° C. for 80 days, the color number change is less than 5 Hazen, and the un-monomer content change is less than or equal to 0.25wt%.

[0155] The above describes some embodiments of the present invention, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. An isocyanate-modified silane coupling agent, characterized in that: When stored at 40°C for 80 days, the following conditions ① and ② are met: ① The increase in the content of isocyanate polymer in the isocyanate-modified silane coupling agent after storage is less than 0.5wt%; ② After storage, the color number of the isocyanate-modified silane coupling agent shall not increase by more than 20% of its initial color number.

2. The silane coupling agent according to claim 1, characterized in that When the isocyanate-modified silane coupling agent is stored at 40° C. for 80 days, the increase in the polymer contained in the isocyanate-modified silane coupling agent is less than or equal to 0.8 wt %.

3. The silane coupling agent according to claim 1 or 2, characterized in that: The structural formula of the isocyanate-modified silane coupling agent is shown in formula (I): In formula (I), R2, R3, and R4 are the same or different, and are independently saturated alkyl and / or saturated alkoxy groups, and at least one of R2, R3, and R4 is a saturated alkoxy group; preferably, the saturated alkyl group is a saturated alkyl group of C1 to C6; the general formula of the saturated alkoxy group is R5O—, in which R5 is preferably a saturated alkyl group of C1 to C6; R1 is a branched or straight chain alkylene or cycloalkylene, arylene, or aralkylene, preferably the branched or straight chain alkylene or cycloalkylene contains 1 to 12 carbon atoms, preferably the arylene contains 6 to 10 carbon atoms, preferably the aralkylene contains 7 to 10 carbon atoms, and R1 is more preferably a branched or straight chain alkylene containing 1 to 6 carbon atoms; Preferably, the C1-C6 saturated alkyl group is methyl, ethyl, n-propyl, isopropyl, n-butyl, or n-pentyl; Preferably, the branched or straight-chain alkylene or cycloalkylene group containing 1-12 carbon atoms is methylene, ethylene, n-propylene, isopropylene, n-butylene, n-pentylene, hexylene, heptylene, octylene, and the aralkylene group containing 7-10 carbon atoms can be, for example, methylenephenyl or ethylenephenyl.

4. The silane coupling agent according to any one of claims 1 to 3, characterized in that: The isocyanate polymer includes one or more of an isocyanurate structure, a carbamate structure, an allophanate structure, a biuret structure, an iminooxadiazinedione structure, a uretdione structure, a carbodiimide structure, and a uretonimine structure; Preferably, the isocyanate polymer is a trimer polyisocyanate, a biuret polyisocyanate or a uretdione polyisocyanate; Preferably, the trimer polyisocyanate includes one or more of an isocyanurate structure, a carbamate structure, an allophanate structure, an iminooxadiazinedione structure, a uretdione structure, a carbodiimide structure and a uretonimine structure; Preferably, the biuret polyisocyanate includes one or more of a biuret structure, a carbodiimide structure, a uretdione structure and a uretonimine structure; Preferably, the uretdione polyisocyanate comprises one or more of a uretdione structure, an isocyanurate structure, a carbamate structure, an allophanate structure, an iminooxadiazinedione structure, a carbodiimide structure and a uretonimine structure.

5. A method for preparing a storage-stable isocyanate-modified silane coupling agent, characterized in that: include: In the presence of a catalyst system, a chlorine-modified silane coupling agent is reacted with a solid cyanate to obtain an isocyanate reaction liquid; the solid raw material and by-product chloride salt remaining in the obtained isocyanate reaction liquid are separated by solid-liquid separation to obtain a filtrate; the obtained filtrate is heat-treated to obtain a heat-treated isocyanate-modified silane coupling agent; and the heat-treated reaction liquid is separated to obtain an isocyanate-modified silane coupling agent.

6. The preparation method according to claim 5, characterized in that: The heat treatment temperature is 5-10° C. higher than the color-sensitive temperature of the obtained isocyanate-modified silane coupling agent, and the heat treatment time is 15-45 min; Preferably, the color-sensitive temperature is that the isocyanate-modified silane coupling agent product is heated at 100-200° C., and the temperature range of the heating is divided into a plurality of isothermal intervals and the color number of the heated product is tested at the temperature intervals. The temperature corresponding to the increase of the product color number by 1.5 times is the color-sensitive temperature. Preferably, a point can be selected every 5°C in the temperature range of 100-200°C and heated for 2 hours to test the product color number corresponding to the temperature point. The measured color number points and the corresponding temperature points are then plotted into a color number-temperature curve. In the resulting curve, the temperature corresponding to the increase of the product color number by 1.5 times is the color-sensitive temperature.

7. The preparation method according to claim 5 or 6, characterized in that: In the synthesis process of the isocyanate-modified silane coupling agent, the structural formula of the raw material chlorine-modified silane coupling agent is shown in formula (III): In formula (II), R2, R3, and R4 are the same or different, and are independently saturated alkyl and / or saturated alkoxy groups, and at least one of R2, R3, and R4 is a saturated alkoxy group; preferably, the saturated alkyl group is a saturated alkyl group of C1 to C6; the general formula of the saturated alkoxy group is R5O—, in which R5 is preferably a saturated alkyl group of C1 to C6; R1 is a branched or straight-chain alkylene or cycloalkylene, arylene or aralkylene, preferably the branched or straight-chain alkylene or cycloalkylene contains 1-12 carbon atoms, preferably the arylene contains 6-10 carbon atoms, preferably the aralkylene contains 7-10 carbon atoms, and R1 is more preferably a branched or straight-chain alkylene containing 1-6 carbon atoms.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The cyanate raw material is selected from one or more alkaline metal cyanates, and the alkaline metal is an alkali metal and / or an alkaline earth metal, preferably Ca, K, Na, Mg; Preferably, the molar amount of the cyanate raw material is 0.9-4.0 times, preferably 1.0-2.0 times, of the chlorine-modified silane coupling agent; Preferably, the catalyst is selected from one or more of chain polyethylene glycol, chain polyethylene glycol dialkyl ether, cyclic crown ether, quaternary ammonium salt, tertiary amine, quaternary ammonium base, quaternary phosphonium salt, metal chloride, preferably one or more of tetrabutylammonium bromide, tetrabutylammonium chloride, 18-crown ether, zinc chloride, pyridine; Preferably, the molar amount of the catalyst is 0.001-0.05 times, preferably 0.005-0.01 times, of the chlorine-modified silane coupling agent; Preferably, the reaction temperature of the reaction is 60-130°C, preferably 85-105°C.

9. The preparation method according to any one of claims 5 to 8, characterized in that: If there is an inert organic solvent in the reaction system, the inert organic solvent can be selected from aromatic hydrocarbons, halogenated aromatic hydrocarbons, halogenated aliphatic hydrocarbons, aliphatic ester compounds or aromatic ester compounds, aliphatic hydrocarbons or aromatic hydrocarbon organic solvents; Preferably, the inert organic solvent has a boiling point lower than the color-sensitive temperature of the product.

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