Carbamate-based silane-terminated polyether as well as preparation method and application thereof

Abstract

The invention provides carbamate-based silane-terminated polyether as well as a preparation method and application thereof. The preparation method of the carbamate-based silane-terminated polyether comprises the following steps: S1, under the protection of nitrogen, mixing carbonic ester, aminoalkyl silane and a catalyst, reacting under reflux until the content of aminoalkyl silane in a system is less than or equal to 0.3%, adjusting the pH value of the system to 6-7 after the reaction is finished, and collecting carbamate-based silane at 140-180 DEG C and-0.07--0.09 MPa; and S2, under the protection of nitrogen, mixing the carbamate-based silane obtained in the step S1 with polyol, and reacting under micro-reflux. The carbamate-based silane-terminated polyether provided by the invention has the advantages of easily available raw materials and mild reaction conditions, is suitable for polyethers with all molecular weights, and is suitable for various aminoalkyl silanes with different activities, and the prepared sealant has moderate surface drying time and good tensile strength.

Description

Technical Field

[0001] The invention relates to the technical field of adhesive synthesis, and more specifically to a carbamate silane-terminated polyether and a preparation method and application thereof. Background Art

[0002] Silane-modified sealants have the advantages of both silicone and polyurethane adhesives, and are widely used in the construction, home improvement and other industries. Conventional silane-modified polyether sealants are mainly based on terminal silane polyether (MS), which can be prepared by hydrosilylation, addition, isocyanate and epoxy ring-opening methods. However, in the prior art, conventionally obtained silane-modified polyether sealants sometimes cannot match the market demand very well. For example, in the prior art, the silane-modified polyether prepared by Michael reaction of low molecular weight polyether amine and aminosilane has a high reaction activity, but when it is prepared into MS glue, gel and other problems are prone to occur during the production process. The silane-modified polyether prepared by ring opening of polyether amine and epoxy silane is prone to yellowing, and the application scenarios are limited. The use of allyl-terminated polyether and hydrogen-containing silane hydrosilylation has double bond polymerization, drought silane compound disproportionation dehydrogenation, and insufficient end-capping rate. In the prior art, polyether sealants cannot take into account both surface drying time and tensile strength very well. Summary of the invention

[0003] In order to solve or at least partially solve the problems in the prior art and to obtain a polyether sealant with a moderate surface drying time and tensile strength, a carbamate silane-terminated polyether and a preparation method thereof are proposed.

[0004] The preparation method of the carbamate silane-terminated polyether provided by the present invention comprises the following steps:

[0005] S1, under nitrogen protection, carbonate, aminosilane and catalyst are mixed, and reacted under reflux until the content of aminosilane in the system is ≤0.3%, after the reaction, the pH value of the system is adjusted to 6-7, and carbamate silane is collected at 140-180° C. and -0.07--0.09 MPa;

[0006] S2, under nitrogen protection, mixing the carbamate silane obtained in step S1 with polyol, distilling and dealcoholizing under reflux until no obvious fraction is produced, removing unreacted carbamate silane, and cooling to room temperature under nitrogen protection to obtain.

[0007] The preparation method provided by the present invention has readily available raw materials, is simple in method, does not require the preparation of isocyanate silane, and has no isocyanate residue. The applicant has found that the sealant prepared by using the carbamate silane-terminated polyether obtained by the preparation method has a moderate surface drying time and the tensile strength of the sealant will not be reduced. In the preferred embodiment, the tensile strength is further improved.

[0008] In a preferred embodiment of the present invention, in step S1, the carbonate is a single or mixed carbonate such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, etc., preferably dimethyl carbonate. In the present invention, the applicant has found that carbonate is easy to absorb water. In order to obtain a solution that can achieve the purpose of the present invention, before use, the water content in the raw material carbonate acid needs to be controlled below 500ppm.

[0009] In a preferred embodiment of the present invention, in step S1, the aminoalkylsilane is γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, N-β-aminoethyl -γ-aminopropylmethyldiethoxysilane, N-(n-butyl)-γ-aminopropyltrimethoxysilane, N-(n-butyl)-γ-aminopropyltriethoxysilane, N-(n-butyl)-γ-aminopropylmethyldimethoxysilane, N-(n-butyl)-γ-aminopropylmethyldiethoxysilane, γ-diethylenetriaminepropylmethyldimethoxysilane, γ-diethylenetriaminepropylmethyldiethoxysilane, N,N-dimethylpropylenediaminopropylmethyl N,N-dimethylpropylenediaminopropylmethyldiethoxysilane, N,N-dimethylpropylenediaminopropyltrimethoxysilane, γ-piperazinylpropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltriethoxysilane, N-phenyl-aminopropylmethyldimethoxysilane, N-phenyl-aminopropylmethyldiethoxysilane, N-phenylα-aminomethyltrimethoxysilane , one of N-phenyl α-aminomethyl triethoxysilane, preferably N,N-dimethylpropylene diaminopropyl trimethoxysilane, γ-piperazine propyl trimethoxysilane, N-phenyl-γ-aminopropyl trimethoxysilane or N-(n-butyl)-γ-aminopropyl trimethoxysilane and other trifunctional secondary aminomethoxysilanes, and further preferably N-phenyl-γ-aminopropyl trimethoxysilane or N-(n-butyl)-γ-aminopropyl trimethoxysilane.

[0010] In a preferred embodiment of the present invention, in step S1, the molar ratio of carbonate to aminosilane is (1.8-2.3):1.

[0011] In the present invention, the catalyst in step S1 can be a titanate coupling agent, an organic tin, an alkali metal, a transition metal, an oxide of an alkali metal, a saturated alcohol solution of an alkali metal, etc., preferably a saturated alcohol solution of an alkali metal, and more preferably a saturated solution of sodium methoxide / methanol. In a specific embodiment of the present invention, the concentration of the saturated alcohol solution of the alkali metal is 10 to 30%, and in a preferred embodiment, the concentration of the saturated solution of sodium methoxide / methanol can be 29 to 29.5%. In a specific embodiment of the present invention, the amount of the catalyst in step S1 is preferably 0.2% to 0.5% of the total mass of the carbonate and aminosilane (i.e., the total mass of the system raw materials (excluding the catalyst)).

[0012] In a specific embodiment of the present invention, in step S1, the reflux temperature is 80-85° C. After the reaction is completed, the pH value of the system is usually adjusted to 6-7 after the system temperature drops to room temperature, and preferably a neutralizer is used to adjust the pH value of the system to 6-7. Among them, the neutralizer is preferably an organic acid such as acetic acid, oxalic acid, or other inorganic acid that can treat the pH to 6-7 without causing hydrolysis reaction between silane and the product, and acetic acid is more preferably used.

[0013] In a preferred embodiment of the present invention, in step S1, after the pH value of the system is adjusted to 6 to 7, atmospheric distillation can be carried out at 100 to 130° C. until no fraction is produced, and then the temperature is reduced to 70 to 90° C., and the unreacted carbonate is recovered at -0.04 to -0.06 MPa, and then the carbamate silane is collected at 140 to 180° C. and -0.07 to -0.09 MPa.

[0014] In a preferred embodiment of the present invention, in step S2, the polyol is polyethylene glycol or polypropylene glycol, and the molecular weight of the polyol is 2000 to 6000. More preferably, the polyol is polypropylene glycol with a molecular weight of 2000 to 6000 (PPG-2000 to PPG-6000), and further preferably, the polyol is polypropylene glycol with a molecular weight of 4000.

[0015] In a preferred embodiment of the present invention, in step S2, the molar ratio of the polyol to the aminosilane in step S1 is (0.45-0.5):1.

[0016] In a specific embodiment of the present invention, in step S2, the reflux temperature is 70-100° C. In the reaction, dealcoholization is carried out while reacting at the reflux temperature (usually by atmospheric distillation). When no obvious fraction is produced, it also marks the end of the reaction.

[0017] In a specific embodiment of the present invention, in order to further improve the performance of the obtained carbamate silane-terminated polyether, in step S2, after removing the unreacted alcohol and amino acid ester silane, it is necessary to cool down to room temperature under nitrogen protection. The applicant unexpectedly found that if the cooling step is carried out in the air or nitrogen is not continuously introduced during the cooling step, the performance of the obtained product will be greatly reduced.

[0018] Another object of the present invention is to provide a carbamate silane-terminated polyether obtained by the above preparation method.

[0019] Another object of the present invention is to provide the above preparation method or the use of the carbamate silane-terminated polyether obtained by the above preparation method in the preparation of building sealants.

[0020] The beneficial effects of the present invention are:

[0021] The preparation method of the carbamate silane-terminated polyether provided by the present invention has readily available raw materials, a simple method, mild reaction conditions, no need to prepare isocyanate silane, no isocyanate residue, and is applicable to polyethers of all molecular weights and to aminoalkylsilanes of various activities (preferably trifunctional secondary aminomethoxysilane). At the same time, without additionally increasing the proportion of polyether-modified silane and each component in the original formula, the sealant prepared by using the carbamate silane-terminated polyether obtained by the preparation method provided by the present invention has a moderate surface drying time (surface drying time is between 13 minutes and 35 minutes) and a high tensile strength (tensile strength is not less than 15.0 MPa, and the tensile strength before and after aging does not change much). DETAILED DESCRIPTION

[0022] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. In the present invention, if there is no special explanation, "%" means mass percentage.

[0023] Example 1

[0024] This embodiment provides a carbamate silane-terminated polyether, and the preparation method comprises the following steps:

[0025] S1, under nitrogen protection, 180.2g of dimethyl carbonate with a water content of 182ppm and 179.3g of γ-aminopropyltrimethoxysilane were heated in 1.2g of a methanol solution containing 29-29.5% sodium methoxide until obvious reflux occurred at about 76°C, and the reaction was kept warm for 2h. The content of γ-aminopropyltrimethoxysilane in the gas phase monitoring system was 0.21%. The mixture was cooled and neutralized with glacial acetic acid to a pH of about 6.4. The mixture was heated to 100-110°C at normal pressure to recover methanol, cooled to 72-75°C, and excess dimethyl carbonate was recovered at -0.04-0.05MPa. The mixture was then heated to 142-145°C, and the fractions were collected by distillation at -0.07-0.08MPa to obtain colorless and transparent methylcarbamate propyltrimethoxysilane.

[0026] S2, under nitrogen protection, heating the methyl carbamate propyl trimethoxysilane obtained in step S1 and 1840g PPG-4000 at 82-85°C to react until slight reflux occurs, and dealcoholizing by atmospheric distillation at the reflux temperature until no obvious fraction is produced, slowly heating to 142-145°C, and removing unreacted methyl carbamate propyl trimethoxysilane under reduced pressure of -0.07-0.08MPa, and cooling under nitrogen protection to obtain a colorless and transparent carbamate silane-terminated polyether.

[0027] Example 2

[0028] The method provided in this embodiment is the same as that in Embodiment 1, except that the aminohydrocarbonsilane is N-phenyl-γ-aminopropyltrimethoxysilane.

[0029] The parameters for collecting the product in step S1 and removing the unreacted product of step S1 in step S2 are: 172 to 175° C., -0.08 to -0.09 MPa.

[0030] Example 3

[0031] The method provided in this embodiment is the same as that in Embodiment 1, except that the aminohydrocarbon silane is N-(n-butyl)-γ-aminopropyltrimethoxysilane.

[0032] The parameters for collecting the product in step S1 and removing the unreacted product of step S1 in step S2 are: 161 to 164° C., -0.07 to -0.08 MPa.

[0033] Example 4

[0034] The method provided in this embodiment is the same as that in Embodiment 1, except that the aminohydrocarbon silane is N-β-aminoethyl-γ-aminopropyltrimethoxysilane.

[0035] The parameters for collecting the product in step S1 and removing the unreacted product of step S1 in step S2 are: 168 to 172° C., -0.08 to -0.09 MPa.

[0036] Example 5

[0037] The method provided in this embodiment is the same as that in embodiment 1, except that the carbonate is diethyl carbonate and the aminoalkylsilane is γ-aminopropyltriethoxysilane.

[0038] The parameters for collecting the product in step S1 and removing the unreacted product of step S1 in step S2 are: 155 to 160° C., -0.08 to -0.09 MPa.

[0039] Example 6

[0040] The method provided in this embodiment is the same as that in Embodiment 2, except that in step S1, the catalyst is tetrabutyl titanate.

[0041] Example 7

[0042] This embodiment provides a carbamate silane-terminated polyether, comprising the following steps:

[0043] S1, under nitrogen protection, 162.2g of dimethyl carbonate with a water content of 182ppm and 255.4g of N-phenyl-γ-aminopropyltrimethoxysilane were heated in 0.84g of a methanol solution containing 29-29.5% sodium methoxide until obvious reflux occurred at about 85-87°C, and the reaction was kept warm for 2h. The N-phenyl-γ-aminopropyltrimethoxysilane in the gas phase monitoring system was 0.24%. The temperature was lowered and glacial acetic acid was added to neutralize to a pH of about 6.5. The mixture was heated to 100-110°C at normal pressure to recover methanol, and then cooled to 81-83°C. Excess dimethyl carbonate was recovered at -0.04-0.05MPa, and then heated to 142-145°C. The fraction was collected by distillation at -0.08-0.09MPa to obtain a colorless and transparent carbamate silane.

[0044] S2, under nitrogen protection, heating the carbamate silane obtained in step S1 and 1800g PPG-4000 at 86-88°C to react until slight reflux occurs, and dealcoholizing by atmospheric distillation at the reflux temperature until no obvious fraction is produced, slowly heating to 142-145°C, and removing unreacted carbamate silane under reduced pressure of -0.08-009MPa, and cooling under nitrogen protection to obtain colorless and transparent carbamate silane-terminated polyether.

[0045] Example 8

[0046] This embodiment provides a carbamate silane-terminated polyether, comprising the following steps:

[0047] S1, under nitrogen protection, 135.2g of dimethyl carbonate with a water content of 182ppm and 255.4g of N-phenyl-γ-aminopropyltrimethoxysilane were heated in 0.40g of a methanol solution containing 29-29.5% sodium methoxide until obvious reflux occurred at about 83-86°C, and the reaction was kept warm for 2h. The content of N-phenyl-γ-aminopropyltrimethoxysilane in the gas phase monitoring system was 0.28%. The temperature was lowered and glacial acetic acid was added to neutralize to a pH of about 6.5. The mixture was heated to 100-110°C at normal pressure to recover methanol, and then the temperature was lowered to 83-85°C. Excess dimethyl carbonate was recovered at -0.04-0.05MPa, and then the temperature was raised to 174-178°C. The fraction was collected by distillation at -0.08-0.09MPa to obtain a colorless and transparent carbamate silane.

[0048] S2, under nitrogen protection, heating the carbamate silane obtained in step S1 and 1600g PPG-4000 at 86-88°C to react until slight reflux occurs, and dealcoholizing by atmospheric distillation at the reflux temperature until no obvious fraction is produced, slowly heating to 174-178°C, and removing unreacted carbamate silane under reduced pressure of -0.08 to -0.09MPa, and cooling under nitrogen protection to obtain colorless and transparent carbamate silane-terminated polyether.

[0049] Example 9

[0050] This embodiment provides a carbamate silane-terminated polyether, comprising the following steps:

[0051] S1, under nitrogen protection, 234.2g of dimethyl carbonate with a water content of 182ppm and 255.4g of N-phenyl-γ-aminopropyltrimethoxysilane were heated in 3.92g of a methanol solution containing 29-29.5% sodium methoxide until obvious reflux occurred at about 79-82°C, and the reaction was kept warm for 2h. The content of N-phenyl-γ-aminopropyltrimethoxysilane in the gas phase monitoring system was 0.12%. The temperature was lowered and glacial acetic acid was added to neutralize to a pH of about 6.5. The mixture was heated to 100-110°C at normal pressure to recover methanol, and then the temperature was lowered to 72-75°C. Excess dimethyl carbonate was recovered at -0.04-0.05MPa, and then the temperature was raised to 173-176°C. The fraction was collected by distillation at -0.08-0.09MPa to obtain a colorless and transparent carbamate silane.

[0052] S2, under nitrogen protection, heating the carbamate silane obtained in step S1 and 2400g PPG-4000 at 80-83°C to react until micro-reflux occurs, and dealcoholizing by atmospheric distillation at the reflux temperature until no obvious fraction is produced, slowly heating to 175-178°C, and removing unreacted carbamate silane under reduced pressure of -0.08 to -0.09MPa, and cooling under nitrogen protection to obtain colorless and transparent carbamate silane-terminated polyether.

[0053] Example 10

[0054] The method provided in this embodiment is the same as that in Embodiment 2, except that the polyol in step S2 is PPG-2000.

[0055] Comparative Example 1

[0056] Under nitrogen protection, 82.1g of isocyanatepropyltrimethoxysilane with a gas phase purity of 98.5% and 400g of PPG-2000 were evenly mixed at room temperature, and 0.3% of the total mass of the mixed raw materials (isocyanatepropyltrimethoxysilane and polypropylene glycol) containing 29-29.5% methanol solution of sodium methoxide was added, and the mixture was reacted at 80°C for 2h. The mixture was distilled at 140-150°C and -0.05-0.04MPa until there were no obvious bubbles.

[0057] Comparative Example 2

[0058] Under nitrogen protection, 86.9g of isocyanatepropylmethyldiethoxysilane with a gas phase purity of 98.2% and 800g of PPG-4000 were mixed evenly at room temperature, and 0.3% by mass of tetrapropyl titanate was added to the mixed raw materials (isocyanatepropyltrimethoxysilane and polypropylene glycol). The mixture was reacted at 80°C for 2h, and the mixture was distilled at 140-150°C and -0.05-0.04MPa until there were no obvious bubbles.

[0059] Experimental example

[0060] The products obtained in the examples and comparative examples of the present invention were used to prepare sealants for performance testing.

[0061] Modification of heavy calcium carbonate: Mix 5 parts of ethanol and 1 part of water evenly, add 1 part of γ-(2,3-epoxypropoxy)propyltrimethoxysilane at about 40°C, keep warm and stir for 2 hours, then add 65 parts of heavy calcium carbonate and stir evenly, dry at 80°C, -0.02~-0.03MPa for 5 hours to obtain epoxysilane-modified calcium carbonate, i.e. modified heavy calcium carbonate.

[0062] The preparation formula and method of the sealant in the experimental example of the present invention are as follows: weigh 35 parts of the carbamate silane-terminated polyether obtained in the above embodiment, 20 parts of PPG-3000, 15 parts of dibutyl phthalate, 8 parts of modified heavy calcium carbonate, and 20 parts of black cat N339 carbon black, and stir at low speed for 10 minutes until uniform; stir at high speed under the conditions of vacuum degree of -0.09 to -0.1 MPa and temperature of 110°C, and dehydrate for 1 hour; then cool to below 35°C, add 0.8 parts of 1,2-bistrimethoxysilylethane (moisture remover), and 0.8 parts of γ-aminopropyltrimethoxysilane, stir at high speed for 15 minutes under the conditions of vacuum degree of -0.09 to -0.1 MPa, add 0.4 parts of dibutyltin dilaurate, continue to stir at high speed for 10 minutes under the conditions of vacuum degree of -0.09 to -0.1 MPa, and then discharge, and prepare specimens according to the standard.

[0063] The surface drying time of the adhesive was tested according to method A specified in GB / T 13477.5-2002, and the adhesive was cured at 23°C and 50% RH for 2 weeks. The tensile strength of the specimens was tested according to GB / T528-2009, and the tensile strength was tested again after the specimens were thermally aged at 90°C for 300 hours. The results are shown in Table 1 below.

[0064] Table 1 Performance test results

[0065]

[0066]

[0067] Finally, the method of the present invention is only a preferred embodiment and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a carbamate silane-terminated polyether, characterized in that: The steps include: S1, under nitrogen protection, carbonate, aminosilane and catalyst are mixed, and reacted under reflux until the content of aminosilane in the system is ≤0.3%, after the reaction, the pH value of the system is adjusted to 6-7, and carbamate silane is collected at 140-180° C. and -0.07--0.09 MPa; S2, under nitrogen protection, mixing the carbamate silane obtained in step S1 with polyol, distilling and dealcoholizing under reflux until no obvious fraction is produced, removing unreacted carbamate silane, and cooling to room temperature under nitrogen protection to obtain.

2. The preparation method according to claim 1, characterized in that: In step S1, the carbonate is one or more of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and ethyl methyl carbonate, preferably dimethyl carbonate.

3. The preparation method according to claim 1, characterized in that: In step S1, the aminoalkylsilane is γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, N-β-aminoethyl-γ-aminopropylmethyldiethoxysilane, N-(n-butyl)-γ-aminopropyltrimethoxysilane, N-(n-butyl)-γ-aminopropyltriethoxysilane, N-(n-butyl)-γ-aminopropylmethyldimethoxysilane, N-(n-butyl)-γ-aminopropylmethyldiethoxysilane, γ-diethylenetriaminepropylmethyldimethoxysilane, Preferably, the present invention is one of 1,2-dimethyl-1,2-diaminopropyl-methyl-diethoxysilane, γ-diethylenetriaminepropylmethyl-diethoxysilane, N,N-dimethylpropylenediaminepropylmethyl-diethoxysilane, N,N-dimethylpropylenediaminepropyl-trimethoxysilane, γ-piperazinylpropyl-trimethoxysilane, N-phenyl-γ-aminopropyl-trimethoxysilane, N-phenyl-γ-aminopropyl-triethoxysilane, N-phenyl--aminopropyl-methyl-dimethoxysilane, N-phenyl--aminopropyl-methyl-diethoxysilane, N-phenyl-α-aminomethyl-trimethoxysilane, and N-phenyl-α-aminomethyl-triethoxysilane, and more preferably N-phenyl-γ-aminopropyl-trimethoxysilane or N-(n-butyl)-γ-aminopropyl-trimethoxysilane.

4. The preparation method according to any one of claims 1 to 3, characterized in that In step S1, the molar ratio of the carbonate to aminosilane is (1.8-2.3):

1.

5. The preparation method according to claim 1, characterized in that: In step S1, the catalyst is a titanate coupling agent, organic tin, alkali metal, transition metal, alkali metal oxide or alkali metal saturated alcohol solution, preferably alkali metal saturated alcohol solution, more preferably sodium methoxide / methanol saturated solution.

6. The preparation method according to claim 5, characterized in that: In step S1, the catalyst is 0.2% to 0.5% of the total mass of carbonate and aminosilane.

7. The preparation method according to any one of claims 1 to 6, characterized in that In step S2, the polyol is polypropylene glycol, and the molecular weight of the polyol is 2000-6000.

8. The preparation method according to any one of claims 1 to 7, characterized in that: In step S2, the molar ratio of the polyol to the aminosilane is (0.45-0.5):

1.

9. The carbamate silane-terminated polyether obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the preparation method according to any one of claims 1 to 8 or the carbamate silane-terminated polyether according to claim 9 in the preparation of a building sealant.

Images