阅读说明：本技术 一种含支化侧链的湿固化硅烷封端聚氨酯 (Moisture-curing silane-terminated polyurethane containing branched side chain ) 是由 张桂霞 刘静韵 米扬 张继生 越磊 于 2020-12-15 设计创作，主要内容包括：本发明涉及一种含支化侧链的湿固化硅烷封端聚氨酯,是由脱水处理的聚醚多元醇与异氟尔酮二异氰酸酯反应,经氨基硅烷封端处理后,再与环氧基硅烷反应生成支化侧链,支化侧链的数量可调控。本发明所提供的含支化侧链的湿固化硅烷封端聚氨酯未固化时具有相对较低的黏度,交联固化后又具有高强度、高模量和高硬度,制备过程中不添加任何有机溶剂,经济环保。(The invention relates to a moisture-curing silane-terminated polyurethane containing branched side chains, which is prepared by reacting dehydrated polyether polyol with isophorone diisocyanate, performing amino silane end capping treatment, and reacting with epoxy silane to generate branched side chains, wherein the number of the branched side chains is adjustable. The moisture-cured silane-terminated polyurethane containing the branched side chain has relatively low viscosity when not cured, has high strength, high modulus and high hardness after crosslinking and curing, does not add any organic solvent in the preparation process, and is economic and environment-friendly.)

1. A moisture-curable silane-terminated polyurethane containing branched side chains, characterized in that: the moisture-curing silane-terminated polyurethane containing the branched side chain is prepared by the following steps:

(1) dehydrating the polyether polyol for 1-2 h at 110-120 ℃ and under the vacuum degree of not less than 0.09 MPa;

(2) reducing the temperature to 85 +/-2 ℃, adding isophorone diisocyanate, carrying out heat preservation reaction for 1 hour under the protection of nitrogen, sampling every 0.5 hour, and determining the mass percent (w) of isocyanate groups (NCO)_NCO) Up to w_NCOThe theoretical design value is reached, and NCO-terminated polyurethane is obtained;

(3) cooling to 65 + -2 deg.C, adding amino silane coupling agent, reacting for 1 hr while keeping the temperature, sampling every 0.5 hr, and measuring w_NCOUp to w_NCOLess than 0.5 percent to obtain silane end-capped polyurethane;

(4) adding a silane coupling agent containing epoxy groups, continuously reacting for 2h, and defoaming in vacuum to obtain the moisture-cured silane-terminated polyurethane containing branched side chains.

2. The moisture-curable, silane-terminated polyurethane having branched side chains according to claim 1, wherein: the addition amount of the isophorone diisocyanate and the polyether polyol is according to the molar ratio R of isocyanate groups (NCO) to hydroxyl groups (OH)_(NCO/OH)1.3-3.0: 1, feeding.

3. The moisture-curable, silane-terminated polyurethane having branched side chains according to claim 1, wherein: the number of moles of the amino-containing silane coupling agent added in step (3) is equal to the number of moles of the terminal NCO groups that have not reacted in step (2).

4. The moisture-curable, silane-terminated polyurethane having branched side chains according to claim 1, wherein: the mole number of the epoxy-containing silane coupling agent added in the step (4) is equal to the mole number of hydroxyl of the polyether polyol multiplied by a coefficient A, and the coefficient A is 0.2-1.

5. The moisture-curable, silane-terminated polyurethane having branched side chains according to claim 1, wherein: the polyether polyol is polypropylene oxide ether dihydric alcohol with the relative molecular weight of 400-4000, and the polyether polyol is any one or the combination of two to three or more of polypropylene oxide polyether polyol with the functionality of 3 and the relative molecular weight of 3000.

6. The moisture-curable, silane-terminated polyurethane having branched side chains according to claim 1, wherein: the amino-containing silane coupling agent is any one of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-N-butyl-3-propyltrimethoxysilane and 3-anilinopropyltrimethoxysilane.

7. The moisture-curable, silane-terminated polyurethane having branched side chains according to claim 1, wherein: the silane coupling agent containing epoxy groups is any one of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane and gamma- (2, 3-epoxypropoxy) propyl triethoxy silane.

8. The moisture-curable, silane-terminated polyurethane having branched side chains according to claim 2, wherein: said R_(NCO/OH)1.5-2.5: 1.

9. the branched side chain-containing moisture-curable silane-terminated polyurethane of claim 1, wherein: the viscosity of the moisture-curing silane-terminated polyurethane containing the branched side chain is 10-80 Pa.s, the tensile strength is 6-19 MPa after curing, the tensile modulus is 40-1.7 GPa, the elongation at break is 20-200%, and the Shore hardness is 50-70.

10. Use of the branched side chain containing moisture-curable silane-terminated polyurethane according to any one of claims 1 to 9 as an adhesive or sealant.

Technical Field

The moisture-curing silane-terminated polyurethane containing the branched side chain can be used as a base resin of adhesives, sealants, coating materials and composite materials and the like to be applied to the fields of buildings, corrosion prevention, transportation, automobile manufacturing and the like.

Background

The chain ends of the one-component moisture-curing silane-terminated polyurethanes (SPUs) are hydrolyzable siloxane groups, which form stable Si-O-Si networks via hydrolysis-condensation reactions under the action of moisture at room temperature, and cure crosslinking is achieved. CO is not released in the curing process₂The problem of air bubbles in the traditional NCO-terminated polyurethane during moisture curing can be avoided. The network structure formed after SPU curing has the dual characteristics of polyurethane chain and Si-O-Si bond, is convenient to construct good balance in the aspects of mechanical property, adhesion property, aging resistance and the like through raw material selection and formula adjustment, and can be used for conventional substrates such as metal, glass, cement, PVC and the like without primer coating. And SPU does not contain free isocyanate, does not produce the polluting exudation while solidifying, colorless and tasteless, will not cause the pollution to substrate and environment, safe and environment-friendly.

Patent CN 103910847 a discloses a silane-terminated polyurethane oligomer and a preparation method thereof, wherein the main material comprises a micromolecular chain extender, a dry solvent, a diisocyanate ester, a catalyst, polyether polyol, secondary aminosilane and the like. The surface drying time of the prepared silane-terminated polyurethane is 0.5-24 h, the actual drying time is 24-100 h, the tensile strength is 0.8-10 MPa, and the elongation at break is 20-300%. Patent CN 108148174A discloses a medium-high modulus silane modified polyurethane resin material and a preparation method thereof, wherein the medium-high modulus silane modified polyurethane resin material is prepared by reacting specific polyether polyol with organic polyisocyanate to obtain a polyurethane prepolymer, and then reacting the polyurethane prepolymer with an aminosilane end-capping agent. The tensile strength of the prepared medium-high modulus silane modified polyurethane resin material is 1.1-1.8 MPa, the elongation at break is 180-270%, and the modulus is 1.3-1.67 MPa.

Practice proves that the moisture-cured siloxane end-capped polyurethane with high strength and adhesion, high modulus and high hardness has wider application window, and is particularly suitable for the fields of fixed adhesion and sealing of structural members such as home decoration, buildings, industrial assembly and the like. However, to achieve high strength, high modulus and high hardness, it is known to give the SPU a relatively dense crosslinked network structure, i.e., to increase the content of hard segments in the SPU, which are derived from isocyanate, and to increase the number of urethane bondsThis results in a higher density of hydrogen bonding when the SPU is uncured, which increases the viscosity of the system. On the other hand, the urea bond generated after the reaction of the terminal NCO group of the SPU blocked by the aminosilane has stronger hydrogen bond generating function, so that the viscosity of the SPU blocked by the aminosilane is further increased and even is in a gelatinous solid-like state. In order to avoid the influence of overhigh viscosity on the construction performance, a solvent is more used for preparing the SPU, or lower R is adopted_(NCO/OH)And higher relative molecular mass polymer polyols, which are not environmentally and healthful, and the modulus, hardness and strength of the cured article are relatively reduced.

Disclosure of Invention

The invention aims to provide the moisture-curing silane-terminated polyurethane containing the branched side chain, which is used for solving the problem of contradiction between high performance and viscosity, namely the provided moisture-curing silane-terminated polyurethane containing the branched side chain has relatively low viscosity when not cured, has high strength, high modulus and high hardness after crosslinking and curing, is not added with any organic solvent in the preparation process, and is economic and environment-friendly.

The purpose of the invention is realized by the following technical scheme:

a moisture-curable, silane-terminated polyurethane containing branched side chains, said moisture-curable, silane-terminated polyurethane containing branched side chains being prepared by the steps of:

(1) adding polyether polyol, heating to 110-120 ℃, and dehydrating for 2 hours under the vacuum degree of not less than 0.09 MPa;

(2) reducing the temperature to 85 +/-2 ℃, adding isophorone diisocyanate, keeping the temperature for reaction for 1 hour, sampling every 0.5 hour to determine the mass percent (w) of isocyanate groups_NCO) Up to w_NCOReaching the theoretical design value;

(3) reducing the temperature of the reaction kettle to 65 +/-2 ℃, adding the silane coupling agent containing amino, keeping the temperature for reaction for 1 hour, sampling every 0.5 hour, and measuring w_NCOUp to w_NCOLess than 0.5%; (ii) a

(4) Adding a silane coupling agent containing epoxy groups, continuing the reaction for 2 hours, and discharging to obtain the moisture-cured silane-terminated polyurethane containing branched side chains.

SaidThe amount of isophorone diisocyanate and polyether polyol added is according to the molar ratio R of isocyanate groups (NCO) to hydroxyl groups (OH)_(NCO/OH)Feeding is carried out for 1.3-3.0, and preferably R_(NCO/OH)Is 1.5 to 2.5. And (3) adding an amino-containing silane coupling agent in the step (3), wherein the mole number of the amino-containing silane coupling agent is equal to that of the unreacted NCO in the step (2). And (3) the mole number of the epoxy-containing silane coupling agent added in the step (4) is equal to the mole number of hydroxyl of the polyether polyol multiplied by a coefficient A (the coefficient A is 0.2-1) in the step (1).

The polyether polyol is polypropylene oxide ether dihydric alcohol with the relative molecular mass of 400-4000, and the polyether polyol is any one or the combination of two to three or more of polypropylene oxide polyether polyol with the functionality of 3 and the relative molecular weight of 3000; the amino-containing silane coupling agent is any one of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-N-butyl-3-propyltrimethoxysilane and 3-anilinopropyltrimethoxysilane; the silane coupling agent containing epoxy groups is any one of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane and gamma- (2, 3-epoxypropoxy) propyl triethoxy silane.

The moisture-curing silane-terminated polyurethane containing the branched side chain has the viscosity of 10-80 Pa.s, the tensile strength of 6-19 MPa after crosslinking and curing, the tensile modulus of 40-1.7 GPa, the elongation at break of 20-200% and the hardness (Shore D) of 50-70, can be used as an adhesive and a sealant, and is suitable for the fields of fixing, bonding, sealing and the like of structural members.

The moisture-curing silane-terminated polyurethane containing the branched side chain is prepared by reacting dehydrated polyether polyol with isophorone diisocyanate, performing amino silane end capping treatment, and reacting with epoxy silane to generate the branched side chain, wherein the number of the branched side chain is adjustable. The moisture-cured silane-terminated polyurethane containing the branched side chain has relatively low viscosity when not cured, has high strength, high modulus and high hardness after crosslinking and curing, does not add any organic solvent in the preparation process, and is economic and environment-friendly.

The invention provides a wet product containing branched side chainsThe cured silane-terminated polyurethane can be packaged in one component and is free of CO during curing₂The release can give a colorless, transparent, bubble-free product.

Compared with the prior art, the invention has the following beneficial effects:

(1) the ring-opening addition reaction of the epoxy group and N-H groups contained in the urethane bond and the urea bond in the SPU molecular chain ensures that SPU molecules contain branched side chain structures, so that the number of hydrogen bond generating groups in the SPU molecules is reduced, the space blocking of the branched side chains also increases the distance between the SPU molecules, the SPU hydrogen bond action degree is weakened, and the reduction of viscosity is facilitated. The magnitude of the viscosity reduction of the uncured SPU can be controlled by the number of branched side chains formed.

(2) The constructed SPU branched side chains with adjustable quantity contain siloxane groups which can chemically react with water, and a plurality of Si-O-Si crosslinking bonds can be generated during curing, so that the crosslinking density of a three-dimensional curing network is greatly improved, and the properties of the material, such as strength, modulus, hardness and the like, can be greatly improved.

(3) The silanol groups generated by a plurality of controllable branched side chains during curing can generate chemical bonding action with metal, glass, polymers containing active groups and the like, and the application field and the application level are expanded.

Drawings

FIG. 1 is an infrared spectrum of the NCO-terminated polyurethane (a) obtained in step (1), the silane-terminated polyurethane (b) obtained in step (2), and the silane-terminated polyurethane (c) having a branched side chain obtained in step (3) of example 1 of the present invention.

FIG. 2 is an infrared spectrum of the NCO-terminated polyurethane (a) obtained in step (1), the silane-terminated polyurethane (b) obtained in step (2), and the silane-terminated polyurethane (c) having a branched side chain obtained in step (3) of example 2 of the present invention.

FIG. 3 is an infrared spectrum of the NCO-terminated polyurethane (a) obtained in step (1), the silane-terminated polyurethane (b) obtained in step (2), and the silane-terminated polyurethane (c) having a branched side chain obtained in step (3) according to example 3 of the present invention.

FIG. 4 is a rheological profile of NCO-terminated polyurethane (a) obtained in step (1), silane-terminated polyurethane (b) obtained in step (2), and silane-terminated polyurethane (c) having a branched side chain obtained in step (3) according to example 3 of the present invention.

FIG. 5 is a rheological profile of NCO-terminated polyurethane (a) obtained in step (1), silane-terminated polyurethane (b) obtained in step (2), and silane-terminated polyurethane (c) having a branched side chain obtained in step (3) of example 4 of the present invention.

FIG. 6 is a rheological profile of NCO-terminated polyurethane (a) obtained in step (1), silane-terminated polyurethane (b) obtained in step (2), and silane-terminated polyurethane (c) having a branched side chain obtained in step (3) of example 5 of the present invention.

FIG. 7 is a stress-strain curve of a cured film of silane-terminated polyurethane containing branched side chains obtained in example 5 of the present invention.

Detailed Description

The present invention is further illustrated in detail with reference to the following examples, but the contents of the present invention are not limited to only the following examples.

The test involved in the invention is carried out as follows:

curing of moisture-curing silane-terminated polyurethanes containing branched side chains: pouring into a polytetrafluoroethylene template, wherein the thickness is 2.0 +/-0.2 mm, dibutyl tin dilaurate is used as a drier, and curing is carried out for 14 days at the temperature of 25 ℃ and the relative humidity (50 +/-5%).

A TH-210 digital Shore D durometer is adopted to carry out hardness test according to GB/T531-1999. The test points are spaced 10mm apart, and the arithmetic mean of the values of 5 test points is taken.

According to GB/T12824-2002, the cured samples are tested by an electronic tensile testing machine, the tensile speed is 5mm/min, the room temperature is 25 ℃, the humidity is 50%, each group of samples tests 5 samples, and the results are averaged.

The test was carried out in an air atmosphere using a DHR-2 rotational rheometer. Selecting rheometer flat plates with the diameter of 25mm, wherein the distance between the flat plates is 1.0mm, and the steady-state frequency scanning is as follows: the test temperature is 30 ℃, and the shear rate ranges from 1 s to 1000s^-1。

Example 1

(1) In the presence of N₂Inlet, vacuum pumping, heating and stirringAdding 50g of polyether polyol DL400D (Shandong Lanxingdong chemical industry Co., Ltd.) and 50g of polyether polyol DL2000D (Shandong Lanxingdong chemical industry Co., Ltd.) into a reaction kettle of the device, heating to 110-120 ℃, and dehydrating for 2h under the vacuum degree of not less than 0.09 MPa;

(2) the temperature of the reaction kettle is reduced to 85 plus or minus 2 ℃, and N is filled₂Protection according to the molar ratio R of the isocyanate groups of the isophorone diisocyanate to the hydroxyl functional groups of the polyether polyol_(NCO/OH)(w 1.5) Isofluorone diisocyanate (50 g) was added, and after keeping the reaction for 1 hour, the mixture was sampled every 0.5 hour to determine the mass percentage of isocyanate groups (w)_NCO) Up to w_NCOReaching the theoretical value of 4.15 percent to obtain NCO-terminated polyurethane;

(3) reducing the temperature of the reaction kettle to 65 +/-2 ℃, adding 15.8g of 3-phenylaminopropyl trimethoxy silane (UP-908 from Nanjing Yoypu chemical Co., Ltd.) according to the mole number equal to the mole number of the unreacted terminal NCO group in the step (2), keeping the temperature for reaction 1, sampling every 0.5h, and measuring w_NCOUp to w_NCOLess than 0.5 percent to obtain silane terminated polyurethane;

(4) adding 20g of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane, continuing to react for 2h, defoaming in vacuum, and discharging to obtain the moisture-curing silane end-capped polyurethane containing branched side chains.

As shown in FIG. 1, infrared spectroscopic analysis was performed on the NCO group-terminated polyurethane, silane-terminated polyurethane and silane-terminated polyurethane having a branched side chain obtained as described above, and the results of the analysis were as follows: 2265cm after silane blocking^-1the-NCO isocyanate characteristic peak disappears, which indicates that the NCO reaction is complete; 821cm^-1The peak of Si-O stretching vibration and 1635cm^-1The absorption peak of the urea carbonyl group appears, which indicates that the blocking agent reacts with the terminal NCO group to form a urea bond.

The viscosity of the moisture-curing silane-terminated polyurethane containing the branched side chain is 73Pa.s, the tensile strength after curing is 18.3MPa, the tensile modulus is 0.98GPa, the elongation at break is 79 percent, and the hardness (Shore D) is 68.

Example 2

(1) In the presence of N₂Polyether polyol DL400D 60g and DL are added into a reaction kettle with an inlet, a vacuumizing device and a stirring device4000.6 g of 4000D (Shandong Lanxingdong chemical industry Co., Ltd.) and 10g of polypropylene oxide polyether polyol MN-3050DF (Shandong Lanxingdong chemical industry Co., Ltd.) are heated to 110-120 ℃ and dehydrated for 2 hours under the vacuum degree of not less than 0.09 MPa;

(2) the temperature of the reaction kettle is reduced to 85 plus or minus 2 ℃, and N is filled₂Protection, adding 87.9g of isophorone diisocyanate for reaction, sampling every 0.5h after 1h to determine the mass percent of isocyanate groups (w)_NCO) Up to w_NCOThe theoretical design value is reached to 10.1 percent;

(3) reducing the temperature of the reaction kettle to 65 +/-2 ℃, adding 74.8g of N-N-butyl-3-propyltrimethoxysilane (UP-905, Nanjing Yopu chemical Co., Ltd.), keeping the temperature for reaction for 1h, sampling every 0.5h, and measuring w_NCOUp to w_NCOLess than 0.5%;

(4) adding 19g of gamma- (2, 3-epoxypropoxy) propyltriethoxysilane, continuing to react for about 2h, carrying out vacuum defoamation, and discharging to obtain the moisture-cured silane-terminated polyurethane containing branched side chains.

As shown in FIG. 2, infrared spectroscopic analysis was performed on the NCO group-terminated polyurethane, silane-terminated polyurethane and silane-terminated polyurethane having a branched side chain obtained as described above, and the results of the analysis were as follows: 2265cm after silane blocking^-1The characteristic peak of the-NCO isocyanate at the position is not completely disappeared, which indicates that NCO is not completely reacted; 821cm^-1The peak of Si-O stretching vibration and 1635cm^-1The absorption peak of the urea carbonyl group appears, which indicates that the blocking agent reacts with the terminal NCO group to form a urea bond.

The moisture-curing silane-terminated polyurethane containing the branched side chain has the viscosity of 53Pa.s, the tensile strength of 13.5MPa after curing, the tensile modulus of 1.62GPa, the elongation at break of 56 percent and the hardness (Shore D) of 61.

Example 3

(1) In the presence of N₂Adding polyether polyol DL400D 61.4.4 g and DL4000D 30.1.1 g into a reaction kettle of an inlet, a vacuumizing and stirring device, heating to 110-120 ℃, and dehydrating for 2 hours under the vacuum degree not less than 0.09 MPa;

(2) the temperature of the reaction kettle is reduced to 85 plus or minus 2 ℃, N2 is filled for protection, 69.6g of isophorone diisocyanate is added for reaction, and every 0 is arranged after 1 hour.5h sampling to determine the mass percent of isocyanate groups (w)_NCO) Up to w_NCOThe theoretical design value is reached to 7.9 percent;

(3) the temperature of the reaction kettle is reduced to 65 plus or minus 2 ℃, 61.7g of N-N-butyl-3-propyltrimethoxysilane is added, the reaction is kept for 1 hour, and samples are taken every 0.5 hour to measure the w_NCOUp to w_NCOLess than 0.5%;

(4) adding 18.5g of gamma- (2.3-epoxypropoxy) propyl trimethoxy silane, continuously reacting for about 2 hours, defoaming in vacuum, and discharging to obtain the moisture-curing silane end-capped polyurethane containing branched side chains.

As shown in FIG. 3, infrared spectroscopic analysis was performed on the NCO group-terminated polyurethane, silane-terminated polyurethane and silane-terminated polyurethane having a branched side chain obtained as described above, and the results of the analysis were as follows: 2265cm after silane blocking^-1the-NCO isocyanate characteristic peak disappears, which indicates that the NCO reaction is complete; 821cm^-1The peak of Si-O stretching vibration and 1635cm^-1The absorption peak of the urea carbonyl group appears, which indicates that the blocking agent reacts with the terminal NCO group to form a urea bond.

As shown in fig. 4, the resulting NCO group-terminated polyurethane, silane-terminated polyurethane, and silane-terminated polyurethane having a branched side chain were subjected to rheological analysis, and the results of the analysis were: the viscosity is obviously increased after the end capping of the silane, 145Pa.s before the end capping is increased to 482Pa.s after the end capping, and the silane cannot effectively flow and deform at a high shear rate; the viscosity is obviously reduced after side chain branching, and is 72.6 Pa.s.

The viscosity of the moisture-curing silane-terminated polyurethane containing the branched side chain is 72.6Pa.s, the tensile strength after curing is 11.6MPa, the tensile modulus is 1.36GPa, the elongation at break is 34.8 percent, and the hardness (Shore D) is 57.

Example 4

(1) In the presence of N₂Adding polyether polyol DL400D 49.7.7 g and polyether polyol DL4000D 49.7.7 g into a reaction kettle of an inlet, a vacuumizing and stirring device, heating to 110-120 ℃, and dehydrating for 2 hours under the vacuum degree ≧ 0.09 MPa;

(2) the temperature of the reaction kettle is reduced to 85 plus or minus 2 ℃, and N is filled₂Protection, adding 62.2g of isophorone diisocyanate for reaction, sampling every 0.5h after 1h to determine the quality of isocyanate groupsPercent by weight (w)_NCO) Up to w_NCOThe theoretical design value is reached to 7.1 percent;

(3) reducing the temperature of the reaction kettle to 65 +/-2 ℃, adding UP-90569.5 g, keeping the temperature for reaction for 1 hour, sampling every 0.5 hour, and measuring w_NCOUp to w_NCOLess than 0.5%;

(4) adding 16.1g of gamma- (2.3-epoxypropoxy) propyl trimethoxy silane, continuously reacting for about 2 hours, defoaming in vacuum, and discharging to obtain the moisture-curing silane end-capped polyurethane containing branched side chains.

As shown in fig. 5, the above-obtained NCO group-terminated polyurethane, silane-terminated polyurethane, and silane-terminated polyurethane having a branched side chain were subjected to rheological analysis, and the results of the analysis were: the viscosity of silane is obviously increased after end capping, and is increased from 129.4Pa.s before end capping to 197.3Pa.s after end capping; the viscosity is obviously reduced after side chain branching, and is 47.3 Pa.s.

The viscosity of the moisture-curing silane-terminated polyurethane containing the branched side chain is 47.3Pa.s, the tensile strength after curing is 13.9MPa, the tensile modulus is 1.56GPa, the elongation at break is 23 percent, and the hardness (Shore D) is 63.

Example 5

(1) In the presence of N₂Adding polyether polyol DL400D 48.6.6 g and DL4000D 48.4.4 g into a reaction kettle of an inlet, a vacuumizing and stirring device, heating to 110-120 ℃, and dehydrating for 2 hours under the vacuum degree not less than 0.09 MPa;

(2) the temperature of the reaction kettle is reduced to 85 plus or minus 2 ℃, and N is filled₂Protection, adding 77.5g of isophorone diisocyanate for reaction, sampling every 0.5h after 1h to determine the mass percent of isocyanate groups (w)_NCO) Up to w_NCOThe theoretical design value is reached to 7.1 percent;

(3) reducing the temperature of the reaction kettle to 65 +/-2 ℃, adding UP-90577.3g, keeping the temperature for reaction for 1 hour, sampling every 0.5 hour, and measuring w_NCOUp to w_NCOLess than 0.5%;

(4) adding 17.5g of gamma- (2.3-epoxypropoxy) propyl trimethoxy silane, continuing to react for about 2 hours, and discharging to obtain the moisture-curing silane-terminated polyurethane containing branched side chains.

As shown in fig. 6, the resulting NCO group-terminated polyurethane, silane-terminated polyurethane, and silane-terminated polyurethane having a branched side chain were subjected to rheological analysis, and the results of the analysis were: the viscosity of the silane is obviously increased after the end capping, the viscosity is increased from 22.3Pa.s before the end capping to 270.8Pa.s after the end capping, and the flow deformation capability is poor at a high shear rate; the viscosity is obviously reduced after side chain branching, and is 65 Pa.s.

As shown in fig. 7, the cured film of the silane-terminated polyurethane containing a branched side chain obtained as described above was subjected to a stress-strain curve test, and the test results were: the tensile strength was 10.3MPa, the tensile modulus was 1.23GPa, and the elongation at break was 82%.

The moisture-curing silane end-capped polyurethane containing the branched side chain has the viscosity of 65Pa.s and the hardness (Shore D) of 58.

Example 6

(1) In the presence of N₂Adding polyether polyol DL400D 45.1.1 g and polyether polyol DL4000D 30.5.5 g into a reaction kettle of an inlet, a vacuumizing and stirring device, heating to 110-120 ℃, and dehydrating for 2 hours under the vacuum degree not less than 0.09 MPa;

(2) the temperature of the reaction kettle is reduced to 85 plus or minus 2 ℃, and N is filled₂Protection, adding 66.8g of isophorone diisocyanate for reaction, sampling every 0.5h after 1h to determine the mass percent of isocyanate groups (w)_NCO) Up to w_NCOThe theoretical design value is reached to 10.6 percent;

(3) reducing the temperature of the reaction kettle to 65 +/-2 ℃, adding UP-90558.4g, keeping the temperature for reaction for 1 hour, sampling every 0.5 hour, and measuring w_NCOUp to w_NCOLess than 0.5%;

(4) adding 28.5g of gamma- (2.3-epoxypropoxy) propyl trimethoxy silane, continuing to react for about 2 hours, and discharging to obtain the moisture-curing silane-terminated polyurethane containing branched side chains.

The moisture-curing silane-terminated polyurethane containing the branched side chain has the viscosity of 14.9Pa.s, the tensile strength of 10.5MPa after curing, the tensile modulus of 74.5MPa, the elongation at break of 120 percent and the hardness (Shore D) of 65.

Example 7

(1) In the presence of N₂Adding polyether polyol DL400D 59.3.3 g and polyether polyol DL4000D 31.5.5 g into a reaction kettle of an inlet, vacuumizing and stirring device, heating to 110-120 ℃, and ensuring the vacuum degree to be not less thanDehydrating for 2 hours under 0.09 MPa;

(2) the temperature of the reaction kettle is reduced to 85 plus or minus 2 ℃, and N is filled₂Protection, adding 87.7g of isophorone diisocyanate for reaction, sampling every 0.5h after 1h to determine the mass percent of isocyanate groups (w)_NCO) Up to w_NCOThe theoretical design value is reached to 10.6 percent;

(3) reducing the temperature of the reaction kettle to 65 +/-2 ℃, adding UP-90567.4g, keeping the temperature for reaction for 1 hour, sampling every 0.5 hour, and measuring w_NCOUp to w_NCOLess than 0.5%;

(4) adding 37.1g of gamma- (2.3-epoxypropoxy) propyl trimethoxy silane, continuing to react for about 2 hours, and discharging to obtain the moisture-curing silane-terminated polyurethane containing branched side chains.

The viscosity of the moisture-cured silane-terminated polyurethane containing the branched side chain is 16.1Pa.s, the tensile strength after curing is 12MPa, the tensile modulus is 41.8MPa, the elongation at break is 150%, and the hardness (Shore D) is 68.

Example 8

(1) In the presence of N₂Adding polyether polyol DL400D 49.6.6 g and DL4000D 20.4.4 g into a reaction kettle of an inlet, a vacuumizing and stirring device, heating to 110-120 ℃, and dehydrating for 2 hours under the vacuum degree not less than 0.09 MPa;

(2) the temperature of the reaction kettle is reduced to 85 plus or minus 2 ℃, and N is filled₂Protection, adding 71.9g of isophorone diisocyanate for reaction, sampling every 0.5h after 1h to determine the mass percent of isocyanate groups (w)_NCO) Up to w_NCOThe theoretical design value is reached to 10.6 percent;

(3) reducing the temperature of the reaction kettle to 65 +/-2 ℃, adding UP-90556.3g, keeping the temperature for reaction for 1 hour, sampling every 0.5 hour, and measuring w_NCOUp to w_NCOLess than 0.5%;

(4) adding 30.9g of gamma- (2.3-epoxypropoxy) propyl trimethoxy silane, continuing to react for about 2 hours, and discharging to obtain the moisture-curing silane-terminated polyurethane containing branched side chains.

The viscosity of the moisture-cured silane-terminated polyurethane containing the branched side chain is 18.6Pa.s, the tensile strength after curing is 9.7MPa, the tensile modulus is 62.3MPa, the elongation at break is 125 percent, and the hardness (Shore D) is 69.