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Environment-friendly siloxane-terminated polyurethane sealant and preparation method thereof

The technology of siloxane-terminated polyurethane and siloxane-terminated polyurethane is applied in the field of siloxane-terminated polyurethane sealant and its preparation, and can solve the problems of low tensile strength, surface pollution of substrate, high viscosity of prepolymer, etc. problems, to achieve the effect of excellent tensile strength and elongation at break, good storage stability, and good oil stain resistance.

Active Publication Date: 2017-09-29
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method also has disadvantages: the reaction of the synthetic prepolymer is quick and easy to gel; the storage stability of the obtained sealant is poor, and it is easy to be cured when it is improperly stored; during the construction process, polyurethane will release carbon dioxide when it is cured by moisture, resulting in a sealant. There are bubbles inside the film, which affects its performance; the obtained sealant has poor bonding effect on glass, metal and other smooth and low surface energy substrates; the viscosity of polyurethane prepolymer is relatively high, which causes inconvenience in later construction
However, this method also has some disadvantages: the surface of the substrate needs to be treated during the construction of the sealant; there is molecular leakage, which will pollute the surface of the substrate; it has a certain irritating smell when it is cured; it is smooth to the surface of glass, metal, etc. Poor adhesion to low surface energy substrates
However, this method also has some disadvantages: the obtained sealant has poor heat resistance, low tensile strength and low hardness.

Method used

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  • Environment-friendly siloxane-terminated polyurethane sealant and preparation method thereof
  • Environment-friendly siloxane-terminated polyurethane sealant and preparation method thereof
  • Environment-friendly siloxane-terminated polyurethane sealant and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] (1) Preparation of NCO-terminated polyurethane prepolymer

[0038] Composition mass (g)

[0039]

[0040] According to the above proportion, the mixture of 30 g of polytetrahydrofuran ether diol 2000 and 60 g of polyglycerol 5000 and 15 g of diphenylmethane diisocyanate were sequentially added to a 250 mL four-neck round bottom flask, and the water bath was heated to 60 °C for 1 h. Then the temperature was raised to 75°C, 0.08 g of stannous octoate was added dropwise to the round-bottomed flask, and nitrogen gas was introduced into the flask to isolate the air. The reaction was carried out at 75°C for 2 hours. Measure the NCO content every 30min, when the NCO content reaches or is less than the theoretical capping value. Cooling and cooling to obtain terminal NCO polyurethane prepolymer.

[0041] (2) Synthesis of a hydroxyl-containing siloxane

[0042] Composition mass (g)

[0043]

[0044] Add 10g methyldiethoxyhydrosilane, 10g allyl alcohol, 20g concentrate...

Embodiment 2

[0054] (1) Preparation of NCO-terminated polyurethane prepolymer

[0055] Composition mass (g)

[0056]

[0057] According to the above ratio, the mixture of 30 polytetrahydrofuran ether diol 1000 and 60 g polyglycerol 6000 and 17 g diphenylmethane diisocyanate were sequentially added to a 250 mL four-neck round bottom flask, and the water bath was heated to 70 °C for 1 h. Subsequently, the temperature was raised to 75° C., 0.08 g of dibutyltin dilaurate was added dropwise to the round-bottomed flask, and nitrogen was introduced into the flask to isolate the air. The reaction was carried out at 75°C for 2 hours. Measure the NCO content every 30min, when the NCO content reaches or is less than the theoretical capping value. Cooling and cooling to obtain terminal NCO polyurethane prepolymer.

[0058] (2) Synthesis of a hydroxyl-containing siloxane

[0059] Composition mass (g)

[0060]

[0061] Add 10g methyldiethoxyhydrosilane, 10g allyl alcohol, 20g concentrated sul...

Embodiment 3

[0071] (1) Preparation of NCO-terminated polyurethane prepolymer

[0072] Composition mass (g)

[0073]

[0074]According to the above ratio, the mixture of 30 g of polytetrahydrofuran ether diol 2000 and 60 g of polyglycerol 6000 and 16 g of toluene diisocyanate were sequentially added to a 250 mL four-neck round bottom flask, and the water bath was heated to 70 °C for 1 h. Subsequently, the temperature was raised to 75°C, 0.1 g of dimorpholine diethyl ether was added dropwise to the round bottom flask, and nitrogen gas was introduced into the flask to isolate the air. The reaction was carried out at 75°C for 2 hours. Measure the NCO content every 30min, when the NCO content reaches or is less than the theoretical capping value. Cooling and cooling to obtain terminal NCO polyurethane prepolymer.

[0075] (2) Synthesis of a hydroxyl-containing siloxane

[0076] Composition mass (g)

[0077]

[0078] Add 10g methyldiethoxyhydrosilane, 10g allyl alcohol, 20g concentra...

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Abstract

The invention discloses an environment-friendly siloxane-terminated polyurethane sealant and a preparation method thereof. First, a NCO-terminated polyurethane prepolymer is prepared, hydroxypropyl siloxane is synthesized, the NCO-terminated polyurethane prepolymer is put in a reaction kettle, a silane coupling agent and the obtained hydroxypropyl methyldiethoxysilane are added into the reaction kettle for heating to 50 to 70 DEG C for reacting for 2-3H; NCO content is tested, and when the NCO content is close to zero, a small molecule volatile capping agent is added, and stirring is performed; triethyl orthoformate is added and stirred after cooling to room temperature, and a siloxane-terminated polyurethane prepolymer is discharged; a plasticizer and an inorganic filler are added, mixed and cooled to room temperature, and an additive and a catalyst are added, and mixed under vacuum conditions; and the obtained environment-friendly siloxane-terminated polyurethane sealant has good stability, can be fast cured at room temperature to obtain an elastic sealant with good mechanical properties, has a very good adhesion effect on glass, metal and other matrixes without a primer.

Description

technical field [0001] The invention relates to a polyurethane sealant, in particular to a siloxane-terminated polyurethane sealant and a preparation method thereof. Background technique [0002] Since the appearance of polyurethane in the 1940s, its prepolymer has been widely used in adhesives and sealants, and is a multifunctional polymer material. Adhesives and sealants are composed of polymers with the highest possible strength. Most adhesives and sealants contain as base materials high molecular weight organics or reactive organics that are precursors to polymers and react during the bonding and sealing process to form polymers. Polyurethane contains a characteristic unit structure. The urethane (-NH-CO-) chain contains alternating soft segments and hard segments, making its aggregated structure a multiphase structure, which determines that the polyurethane material has excellent wear resistance. flexibility and other properties. [0003] At present, the general-purp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09J175/08C09J11/04C09J11/06C08G18/66C08G18/48C08G18/38C08G18/12C08G18/20
CPCC08G18/12C08G18/2081C08G18/4812C08G18/4854C08K3/04C08K3/36C08K13/02C08K2003/2206C08K2003/265C08L2201/08C09J11/04C09J11/06C09J175/08C08G18/289C08L91/06C08K3/26C08K3/22
Inventor 傅和青谢金刚
Owner SOUTH CHINA UNIV OF TECH
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