CN108530603B - Mica modified waterborne polyurethane emulsion, adhesive and preparation method thereof - Google Patents

Abstract

The invention discloses a mica modified waterborne polyurethane emulsion, an adhesive and a preparation method thereof. Pre-polymerizing oligomer polyol and diisocyanate, adding KH-580 modified mica, adding a carboxylic acid type hydrophilic monomer, a chain extender and a cross-linking agent after reaction, adding acetone for viscosity reduction, neutralizing, dispersing and emulsifying, and removing the acetone by reduced pressure distillation to obtain the mica modified waterborne polyurethane emulsion. And adding the obtained emulsion into auxiliaries such as a water-based thickening agent, a flatting agent, a defoaming agent, a plasticizer and the like to prepare the mica modified water-based polyurethane adhesive. The invention improves the water resistance, mechanical property and bonding strength of the waterborne polyurethane adhesive, and is suitable for bonding shoe materials and leather. The adhesive prepared by the invention has excellent hardness, adhesive force, peeling strength, water resistance and the like after being formed into a film. The pencil hardness is 3H at most, the adhesive force can reach 0 grade at most, the water absorption rate can reach 3.3% at least, and the peel strength is 205-220N/2.5 cm.

Description

Mica-modified waterborne polyurethane emulsion, adhesive and preparation method thereof

technical field

The invention relates to the field of water-based adhesives, in particular to a mica-modified water-based polyurethane emulsion, a mica-modified water-based polyurethane adhesive and a preparation method thereof.

Background technique

Waterborne polyurethane is a polyurethane system with water instead of organic solvent as the dispersion medium, also known as water-dispersed polyurethane, water-based polyurethane or water-based polyurethane. Water-based polyurethane uses water as a solvent and has the advantages of no pollution, safety and reliability, excellent mechanical properties, good compatibility, and easy modification. In recent years, it has been widely used in coatings, adhesives, fabric coatings and finishing agents, and leather finishing. agent, paper surface treatment agent and fiber surface treatment agent. At present, polyurethane adhesives have been widely used in the shoe industry due to their excellent bonding properties. However, most of the domestic polyurethane adhesives for shoes are mainly solvent-based, and toxic and harmful organic solvents can easily cause environmental pollution and damage human life safety. The environmentally friendly water-based polyurethane adhesive uses water as the dispersion medium, and has the advantages of adjustable hardness, low temperature resistance, good flexibility, flame retardant, low odor, and no environmental pollution. Considering the factors of human environment and life safety, the development and application of environmentally friendly water-based polyurethane adhesives for shoes will definitely become the mainstream direction in the future (Sudipta M, Krishanmurti N. Synthesis and characterization of aqueouscationomeric polyurethanes and their use as adhesives[J].J]. .Appl.Polym Sci, 1996, 62:1993-2003.). At present, domestic high-quality environmentally friendly water-based polyurethane adhesives for shoes are still rare in the market. The main reason is that the solid content is low, and there are still low initial adhesion, slow curing speed, and adhesion to non-polar materials in use. It has the disadvantages of low bonding strength, poor mechanical properties and poor water resistance (Noble K L. Waterborne polyurethane [J]. Progress in Organic Coatings, 1997, 32 (3): 131-136).

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a mica-modified water-based polyurethane emulsion, an adhesive and a preparation method thereof.

To achieve the above object, the present invention has adopted the following technical solutions:

The preparation method of mica-modified water-based polyurethane emulsion comprises the following steps:

In step 1, diisocyanate is added dropwise to the anhydrous oligomer polyol, and under stirring, the catalyst is added dropwise, and the reaction is carried out at 80 to 85° C. for 1 to 2 hours to obtain the first intermediate, wherein the oligomer polyol and the polyol are added dropwise. The weight ratio of isocyanate is 1800～2400:1200～1500;

Step 2, taking the total mass of oligomer polyol, diisocyanate, polyhydroxy carboxylic acid, small molecule diol monomer and crosslinking agent as the total amount, according to γ-mercaptopropyl triethoxysilane (KH- 580 modified) mica (hereinafter referred to as mica) and the total weight ratio of 6 to 14:50, the mica and the first intermediate are mixed and reacted with stirring to obtain the second intermediate;

Step 3, cooling the second intermediate to 60-70 °C, adding dry polyhydroxycarboxylic acid, and reacting for 2-3 hours to obtain the third intermediate;

Step 4, drop a small molecule diol monomer into the third intermediate, and add an organic solvent to reduce the viscosity until the solution is colorless, heat up to 70-80 ° C, and react for 1-2 hours to obtain the fourth intermediate;

In step 5, a cross-linking agent is added dropwise to the fourth intermediate, and the reaction is carried out at 60-70° C. for 2-3 hours to obtain the fifth intermediate;

Step 6, cooling the fifth intermediate to 20-35° C., adding organic amine to neutralize and forming a salt under stirring, and reacting for 0.5-1 hour to obtain the sixth intermediate;

Step 7, adding water to the sixth intermediate for shear emulsification, the shear speed is controlled at 2000-3000 r/min, the reaction is performed for 0.5-1 hour, and the organic solvent is removed by rotary evaporation to obtain a mica-modified aqueous polyurethane emulsion.

In step 1, the number average molecular weight of the oligomer polyol is 1000-4000, and the oligomer polyol is selected from polycaprolactone diol, polyhexamethylene adipate diol, One or both of polytetrahydrofurandiol, hydroxyl-terminated polybutadiene, and hydroxyl-terminated polybutadiene-acrylonitrile.

In step 1, the diisocyanate is selected from norbornane diisocyanate, lysine diisocyanate, naphthalene diisocyanate, diphenylmethane-4,4'-diisocyanate, xylylene diisocyanate, cyclohexane One or more of alkane diisocyanate, tetramethylisoxylylene diisocyanate, and 2-methylpentane diisocyanate.

In step 1, the catalyst is stannous octoate or dibutyltin dilaurate.

In step 2, the mass ratio of the diisocyanate, the polyhydroxycarboxylic acid, the small molecule diol, and the crosslinking agent is 720-2600:430-650:160-360:400-600.

In step 3, the polyhydroxy carboxylic acid is selected from one or both of dimethylol propionic acid and dimethylol butyric acid.

In step 4, the small molecule diol monomer is selected from 2-methyl-2,4-pentanediol, TCD tricyclic diol, trimethylpentanediol, methylpropanediol, 1,6- One or more of hexanediol and neopentyl glycol; the organic solvent is selected from one or more of acetone, butanone and nitrogen methyl pyrrolidone.

In step 5, described cross-linking agent is selected from a kind of in triethanolamine, pentaerythritol and glycerol;

In step 6, the organic amine is selected from a kind of triethylamine, ammonia water and sodium hydroxide, and the molar ratio of the organic amine to the polyhydroxycarboxylic acid is 1:1.

The present invention also provides the mica-modified aqueous polyurethane emulsion prepared by the above preparation method.

Further, the present invention provides an adhesive based on the above-mentioned mica-modified water-based polyurethane emulsion, in parts by weight, comprising the following components:

Mica-modified water-based polyurethane emulsion 80-110 parts,

Aqueous thickener 0.1～0.3 part,

Water-based leveling agent 0.15～0.25 parts,

Water-based defoamer 0.2 to 0.4 parts,

4 to 7 parts of plasticizer,

14-26 parts of talcum powder,

Titanium dioxide 2 to 6 parts,

Fumed silica 0.2 to 0.8 parts,

3 to 8 parts of water-based curing agent.

Further, the present invention provides the preparation method of the above-mentioned mica-modified water-based polyurethane adhesive, comprising the following steps:

80-110 parts by weight of mica-modified water-based polyurethane emulsion are added with 0.1-0.3 parts by weight of water-based thickener, 0.15-0.25 parts by weight of water-based leveling agent, 0.2-0.4 parts by weight of water-based defoamer, and 4-7 parts by weight of plasticizer agent, 14-26 parts by weight of talc, 2-6 parts by weight of titanium dioxide and 0.2-0.8 parts by weight of fumed silica, and stir, add 3-8 parts by weight of water-based curing agent, and stir for 10-20 minutes to obtain a mica-modified water-based solution. Polyurethane adhesive.

The aqueous thickener is selected from one of Borchi Gel LW44, Borchi Gel L75N, BENAQUA 4000 and BENAQUA 1000.

The water-based leveling agent is selected from one of BYK-361N, BYK-359, BYK-356 and BYK-350.

The water-based defoamer is selected from one of BYK-019, BYK-021, BYK-024, BYK-093 and BYK-1730.

The plasticizer is selected from the group consisting of dimethyl phthalate, diethyl phthalate and dibutyl phthalate.

The water-based curing agent is selected from one of water-based polyisocyanate curing agents Desmodur DN, Bayhydur3100, Bayhydur XP2487/1, Bayhydur XP2547 and Bayhydur XP2451.

Compared with the prior art, the present invention has the following advantages:

In the invention, the water-based polyurethane emulsion is modified by mica, and the prepared mica-modified water-based polyurethane adhesive has strong adhesion, good bonding performance, improved film-forming property, and improved water resistance and mechanical properties. Mica-modified water-based polyurethane emulsion is combined with other additives, and the obtained water-based polyurethane adhesive has excellent peeling force and tensile strength. The mica-modified water-based polyurethane adhesive prepared by the invention is especially suitable for the fields of shoe materials, packaging films, leather and the like. The experimental results show that the adhesive prepared by this method has excellent hardness, adhesion, peel strength and water resistance after film formation. The pencil hardness is up to 3H, the adhesion is up to grade 0, the water absorption rate is up to 3.3%, and the peel strength is 205-220N/2.5cm.

Detailed ways

In order to better understand the present invention, the present invention will be further described in detail below with reference to the embodiments. The claimed scope of the present invention is not limited to the scope represented by the embodiments.

Comparative Example 1: Unmodified Waterborne Polyurethane Adhesive

(1) Synthesis of waterborne polyurethane emulsion

raw material:

Polycaprolactone diol 10.54g Hydroxy-terminated polybutadiene 8.10g xylylene diisocyanate 20.87g Dibutyltin dilaurate 0.2g KH-580 modified mica 0 Dimethylolpropionic acid 3g TCD tricyclic diol 3.05g acetone 15ml Pentaerythritol 3.31g triethylamine 0.92g Deionized water 130g

Preparation method: add polycaprolactone diol, 2000 hydroxy-terminated polybutadiene 2000 and xylylene diisocyanate into a three-necked flask, add dibutyltin dilaurate and react at 82 ° C for 2 hours to obtain polyurethane prepolymer body, cooled to 65°C, added dimethylolpropionic acid to react for 2h, heated to 75°C, added TCD tricyclic diol, reacted for 1.5h, added 15ml acetone to reduce the viscosity of the reaction system until the solution was colorless and smooth Stir. Then add pentaerythritol, react for 2.5h, cool down to 20°C, add triethylamine for neutralization reaction, neutralize for 0.5h, finally add deionized water for shear emulsification, react for 0.5h, remove acetone by rotary evaporation, and obtain water-based polyurethane emulsion .

(2) Synthesis of water-based polyurethane adhesive

Add 0.2g water-based thickener Borchi Gel LW44, 0.2g water-based leveling agent BYK-361N, 0.3g water-based defoamer BYK-019, 6g plasticizer dimethyl phthalate, 18g of talc, 4g of titanium dioxide, 0.7g of fumed silica, and 5g of water-based curing agent Bayhydur3100 are used to obtain a water-based polyurethane adhesive.

Comparative Example 2: Mica-modified water-based polyurethane adhesive (the weight ratio of mica to the total amount is 2:50)

(1) Synthesis of mica-modified aqueous polyurethane emulsion

raw material:

Polycaprolactone diol 10.54g Hydroxy-terminated polybutadiene 8.10g xylylene diisocyanate 20.87g Dibutyltin dilaurate 0.2g KH-580 modified mica 2g Dimethylolpropionic acid 3g TCD tricyclic diol 3.05g acetone 15ml Pentaerythritol 3.31g triethylamine 0.92g Deionized water 130g

Preparation method: add polycaprolactone diol, 2000 hydroxy-terminated polybutadiene 2000 and xylylene diisocyanate into a three-necked flask, add dibutyltin dilaurate and react at 82 ° C for 2 hours to obtain polyurethane prepolymer body, add 2g KH-580 modified mica, and react for 2h. Cool to 65°C, add dimethylolpropionic acid to react for 2h, heat up to 75°C, add TCD tricyclic diol, react for 1.5h, add 15ml acetone to reduce the viscosity of the reaction system until the solution is colorless and can be stirred smoothly. Then add pentaerythritol, react for 2.5h, cool down to 20℃, add triethylamine for neutralization reaction, neutralize for 0.5h, finally add deionized water for shear emulsification, react for 0.5h, remove acetone by rotary evaporation, and obtain mica modification Waterborne polyurethane emulsion.

(2) Synthesis of mica-modified water-based polyurethane adhesive

Add 0.2g water-based thickener Borchi Gel LW44, 0.2g water-based leveling agent BYK-361N, 0.3g water-based defoamer BYK-019, 6g plasticizer phthalic acid per 100g of mica-modified water-based polyurethane emulsion Dimethyl ester, 18 g of talc, 4 g of titanium dioxide, 0.7 g of fumed silica, and 5 g of water-based curing agent Bayhydur3100 to obtain a mica-modified water-based polyurethane adhesive.

Comparative Example 3: Mica-modified water-based polyurethane adhesive (the weight ratio of mica to the total amount is 4:50)

(1) Synthesis of mica-modified aqueous polyurethane emulsion

raw material:

Polycaprolactone diol 10.54g Hydroxy-terminated polybutadiene 8.10g xylylene diisocyanate 20.87g Dibutyltin dilaurate 0.2g KH-580 modified mica 4g Dimethylolpropionic acid 3g TCD tricyclic diol 3.05g acetone 15ml Pentaerythritol 3.31g triethylamine 0.92g Deionized water 130g

Preparation method: add polycaprolactone diol, 2000 hydroxy-terminated polybutadiene 2000 and xylylene diisocyanate into a three-necked flask, add dibutyltin dilaurate and react at 82 ° C for 2 hours to obtain polyurethane prepolymer body, add 4g KH-580 modified mica, and react for 2h. Cool to 65°C, add dimethylolpropionic acid to react for 2h, heat up to 75°C, add TCD tricyclic diol, react for 1.5h, add 15ml acetone to reduce the viscosity of the reaction system until the solution is colorless and can be stirred smoothly. Then add pentaerythritol, react for 2.5h, cool down to 20℃, add triethylamine for neutralization reaction, neutralize for 0.5h, finally add deionized water for shear emulsification, react for 0.5h, remove acetone by rotary evaporation, and obtain mica modification Waterborne polyurethane emulsion.

(2) Synthesis of mica-modified water-based polyurethane adhesive

Add 0.2g water-based thickener Borchi Gel LW44, 0.2g water-based leveling agent BYK-361N, 0.3g water-based defoamer BYK-019, 6g plasticizer phthalic acid per 100g of mica-modified water-based polyurethane emulsion Dimethyl ester, 18 g of talc, 4 g of titanium dioxide, 0.7 g of fumed silica, and 5 g of water-based curing agent Bayhydur3100 to obtain a mica-modified water-based polyurethane adhesive.

Comparative Example 4: Mica-modified water-based polyurethane adhesive (the weight ratio of mica to the total amount is 16:50)

(1) Synthesis of mica-modified aqueous polyurethane emulsion

raw material:

Polycaprolactone diol 10.54g Hydroxy-terminated polybutadiene 8.10g xylylene diisocyanate 20.87g Dibutyltin dilaurate 0.2g KH-580 modified mica 16g Dimethylolpropionic acid 3g TCD tricyclic diol 3.05g acetone 15ml Pentaerythritol 3.31g triethylamine 0.92g Deionized water 130g

Preparation method: add polycaprolactone diol, 2000 hydroxy-terminated polybutadiene 2000 and xylylene diisocyanate into a three-necked flask, add dibutyltin dilaurate and react at 82 ° C for 2 hours to obtain polyurethane prepolymer body, add 16g KH-580 modified mica, and react for 2h. Cool to 65°C, add dimethylolpropionic acid to react for 2h, heat up to 75°C, add TCD tricyclic diol, react for 1.5h, add 15ml acetone to reduce the viscosity of the reaction system until the solution is colorless and can be stirred smoothly. Then add pentaerythritol, react for 2.5h, cool down to 20℃, add triethylamine for neutralization reaction, neutralize for 0.5h, finally add deionized water for shear emulsification, react for 0.5h, remove acetone by rotary evaporation, and obtain mica modification Waterborne polyurethane emulsion.

(2) Synthesis of mica-modified water-based polyurethane adhesive

Add 0.2g water-based thickener Borchi Gel LW44, 0.2g water-based leveling agent BYK-361N, 0.3g water-based defoamer BYK-019, 6g plasticizer phthalic acid per 100g of mica-modified water-based polyurethane emulsion Dimethyl ester, 18 g of talc, 4 g of titanium dioxide, 0.7 g of fumed silica, and 5 g of water-based curing agent Bayhydur3100 to obtain a mica-modified water-based polyurethane adhesive.

Comparative Example 5: Mica-modified water-based polyurethane adhesive (the weight ratio of mica to the total amount is 18:50)

(1) Synthesis of mica-modified aqueous polyurethane emulsion

raw material:

Preparation method: add polycaprolactone diol, 2000 hydroxy-terminated polybutadiene 2000 and xylylene diisocyanate into a three-necked flask, add dibutyltin dilaurate and react at 82 ° C for 2 hours to obtain polyurethane prepolymer body, add 18g KH-580 modified mica, and react for 2h. Cool to 65°C, add dimethylolpropionic acid to react for 2h, heat up to 75°C, add TCD tricyclic diol, react for 1.5h, add 15ml acetone to reduce the viscosity of the reaction system until the solution is colorless and can be stirred smoothly. Then add pentaerythritol, react for 2.5h, cool down to 20℃, add triethylamine for neutralization reaction, neutralize for 0.5h, finally add deionized water for shear emulsification, react for 0.5h, remove acetone by rotary evaporation, and obtain mica modification Waterborne polyurethane emulsion.

(2) Synthesis of mica-modified water-based polyurethane adhesive

Add 0.2g water-based thickener Borchi Gel LW44, 0.2g water-based leveling agent BYK-361N, 0.3g water-based defoamer BYK-019, 6g plasticizer phthalic acid per 100g of mica-modified water-based polyurethane emulsion Dimethyl ester, 18 g of talc, 4 g of titanium dioxide, 0.7 g of fumed silica, and 5 g of water-based curing agent Bayhydur3100 to obtain a mica-modified water-based polyurethane adhesive.

Embodiment 1: Mica-modified water-based polyurethane adhesive (the weight ratio of mica to the total amount is 6:50)

(1) Synthesis of mica-modified aqueous polyurethane emulsion

raw material:

Preparation method: add polycaprolactone diol, 2000 hydroxy-terminated polybutadiene 2000 and xylylene diisocyanate into a three-necked flask, add dibutyltin dilaurate and react at 82 ° C for 2 hours to obtain polyurethane prepolymer body, add 6g KH-580 modified mica, and react for 2h. Cool to 65°C, add dimethylolpropionic acid to react for 2h, heat up to 75°C, add TCD tricyclic diol, react for 1.5h, add 15ml acetone to reduce the viscosity of the reaction system until the solution is colorless and can be stirred smoothly. Then add pentaerythritol, react for 2.5h, cool down to 20℃, add triethylamine for neutralization reaction, neutralize for 0.5h, finally add deionized water for shear emulsification, react for 0.5h, remove acetone by rotary evaporation, and obtain mica modification Waterborne polyurethane emulsion.

(2) Synthesis of mica-modified water-based polyurethane adhesive

Add 0.2g water-based thickener Borchi Gel LW44, 0.2g water-based leveling agent BYK-361N, 0.3g water-based defoamer BYK-019, 6g plasticizer phthalic acid per 100g of mica-modified water-based polyurethane emulsion Dimethyl ester, 18 g of talc, 4 g of titanium dioxide, 0.7 g of fumed silica, and 5 g of water-based curing agent Bayhydur3100 to obtain a mica-modified water-based polyurethane adhesive.

Example 2: Mica-modified water-based polyurethane adhesive (the weight ratio of mica to the total amount is 8:50)

(1) Synthesis of mica-modified aqueous polyurethane emulsion

raw material:

Preparation method: add polycaprolactone diol, 2000 hydroxy-terminated polybutadiene 2000 and xylylene diisocyanate into a three-necked flask, add dibutyltin dilaurate and react at 82 ° C for 2 hours to obtain polyurethane prepolymer body, add 8g KH-580 modified mica, and react for 2h. Cool to 65°C, add dimethylolpropionic acid to react for 2h, heat up to 75°C, add TCD tricyclic diol, react for 1.5h, add 15ml acetone to reduce the viscosity of the reaction system until the solution is colorless and can be stirred smoothly. Then add pentaerythritol, react for 2.5h, cool down to 20℃, add triethylamine for neutralization reaction, neutralize for 0.5h, finally add deionized water for shear emulsification, react for 0.5h, remove acetone by rotary evaporation, and obtain mica modification Waterborne polyurethane emulsion.

(2) Synthesis of mica-modified water-based polyurethane adhesive

Add 0.2g water-based thickener Borchi Gel LW44, 0.2g water-based leveling agent BYK-361N, 0.3g water-based defoamer BYK-019, 6g plasticizer phthalic acid per 100g of mica-modified water-based polyurethane emulsion Dimethyl ester, 18 g of talc, 4 g of titanium dioxide, 0.7 g of fumed silica, and 5 g of water-based curing agent Bayhydur3100 to obtain a mica-modified water-based polyurethane adhesive.

Example 3: Mica-modified water-based polyurethane adhesive (the weight ratio of mica to the total amount is 10:50)

(1) Synthesis of mica-modified aqueous polyurethane emulsion

raw material:

Preparation method: add polycaprolactone diol, 2000 hydroxy-terminated polybutadiene 2000 and xylylene diisocyanate into a three-necked flask, add dibutyltin dilaurate and react at 82 ° C for 2 hours to obtain polyurethane prepolymer body, add 10g KH-580 modified mica, and react for 2h. Cool to 65°C, add dimethylolpropionic acid to react for 2h, heat up to 75°C, add TCD tricyclic diol, react for 1.5h, add 15ml acetone to reduce the viscosity of the reaction system until the solution is colorless and can be stirred smoothly. Then add pentaerythritol, react for 2.5h, cool down to 20℃, add triethylamine for neutralization reaction, neutralize for 0.5h, finally add deionized water for shear emulsification, react for 0.5h, remove acetone by rotary evaporation, and obtain mica modification Waterborne polyurethane emulsion.

(2) Synthesis of mica-modified water-based polyurethane adhesive

Add 0.2g water-based thickener Borchi Gel LW44, 0.2g water-based leveling agent BYK-361N, 0.3g water-based defoamer BYK-019, 6g plasticizer phthalic acid per 100g of mica-modified water-based polyurethane emulsion Dimethyl ester, 18 g of talc, 4 g of titanium dioxide, 0.7 g of fumed silica, and 5 g of water-based curing agent Bayhydur3100 to obtain a mica-modified water-based polyurethane adhesive.

Example 4: Mica-modified water-based polyurethane adhesive (the weight ratio of mica to the total amount is 12:50)

(1) Synthesis of mica-modified aqueous polyurethane emulsion

raw material:

Preparation method: add polycaprolactone diol, 2000 hydroxy-terminated polybutadiene 2000 and xylylene diisocyanate into a three-necked flask, add dibutyltin dilaurate and react at 82 ° C for 2 hours to obtain polyurethane prepolymer body, add 12g KH-580 modified mica, and react for 2h. Cool to 65°C, add dimethylolpropionic acid to react for 2h, heat up to 75°C, add TCD tricyclic diol, react for 1.5h, add 15ml acetone to reduce the viscosity of the reaction system until the solution is colorless and can be stirred smoothly. Then add pentaerythritol, react for 2.5h, cool down to 20℃, add triethylamine for neutralization reaction, neutralize for 0.5h, finally add deionized water for shear emulsification, react for 0.5h, remove acetone by rotary evaporation, and obtain mica modification Waterborne polyurethane emulsion.

(2) Synthesis of mica-modified water-based polyurethane adhesive

Add 0.2g water-based thickener Borchi Gel LW44, 0.2g water-based leveling agent BYK-361N, 0.3g water-based defoamer BYK-019, 6g plasticizer phthalic acid per 100g of mica-modified water-based polyurethane emulsion Dimethyl ester, 18 g of talc, 4 g of titanium dioxide, 0.7 g of fumed silica, and 5 g of water-based curing agent Bayhydur3100 to obtain a mica-modified water-based polyurethane adhesive.

Example 5: Mica-modified water-based polyurethane adhesive (the weight ratio of mica to the total amount is 14:50)

(1) Synthesis of mica-modified aqueous polyurethane emulsion

raw material:

Polycaprolactone diol 10.54g Hydroxy-terminated polybutadiene 8.10g xylylene diisocyanate 20.87g Dibutyltin dilaurate 0.2g KH-580 modified mica 14g Dimethylolpropionic acid 3g TCD tricyclic diol 3.05g acetone 15ml Pentaerythritol 3.31g triethylamine 0.92g Deionized water 130g

Preparation method: add polycaprolactone diol, 2000 hydroxy-terminated polybutadiene 2000 and xylylene diisocyanate into a three-necked flask, add dibutyltin dilaurate and react at 82 ° C for 2 hours to obtain polyurethane prepolymer body, add 14g KH-580 modified mica, and react for 2h. Cool to 65°C, add dimethylolpropionic acid to react for 2h, heat up to 75°C, add TCD tricyclic diol, react for 1.5h, add 15ml acetone to reduce the viscosity of the reaction system until the solution is colorless and can be stirred smoothly. Then add pentaerythritol, react for 2.5h, cool down to 20℃, add triethylamine for neutralization reaction, neutralize for 0.5h, finally add deionized water for shear emulsification, react for 0.5h, remove acetone by rotary evaporation, and obtain mica modification Waterborne polyurethane emulsion.

(2) Synthesis of mica-modified water-based polyurethane adhesive

Add 0.2g water-based thickener Borchi Gel LW44, 0.2g water-based leveling agent BYK-361N, 0.3g water-based defoamer BYK-019, 6g plasticizer phthalic acid per 100g of mica-modified water-based polyurethane emulsion Dimethyl ester, 18 g of talc, 4 g of titanium dioxide, 0.7 g of fumed silica, and 5 g of water-based curing agent Bayhydur3100 to obtain a mica-modified water-based polyurethane adhesive.

The water-based polyurethane adhesives obtained in Comparative Examples 1 to 5 and Examples 1 to 5 were prepared into films.

Preparation of film samples: The water-based polyurethane emulsion was cast in a polytetrafluoroethylene mold to form a film with a film thickness of about 1 mm, naturally dried for 48 hours, and then placed in a vacuum oven at 60 °C for vacuum drying to constant weight, then taken out and placed in a desiccator spare.

Table 1 Comparative Examples 1-5 and Examples 1-5 film performance test results:

sample name hardness Adhesion (grade) Water absorption (%) Peel Strength (N/2.5cm) Comparative Example 1 4B 4 19.2 67 Comparative Example 2 3B 3 18.4 74 Comparative Example 3 HB 3 18.2 83 Comparative Example 4 HB 3 18.8 90 Comparative Example 5 3B 3 19.6 82 Example 1 3H 0 4.5 205 Example 2 3H 0 4.2 213 Example 3 3H 0 3.3 220 Example 4 3H 0 3.5 209 Example 5 3H 0 4.7 190

It can be seen from the above table that after the water-based polyurethane adhesive is modified by mica, the performance of the coating film is significantly improved, and it has excellent hardness, adhesion, peel strength, water resistance, etc. The pencil hardness is up to 3H, the adhesion is up to grade 0, the water absorption rate is up to 3.3%, and the peel strength is 205-220N/2.5cm.

Obviously, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation manner. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. And the obvious changes or changes derived from this are still within the protection scope of the present invention.

Claims (10)

1. the preparation method of mica-modified water-based polyurethane emulsion, is characterized in that, comprises the following steps: In step 1, diisocyanate is added dropwise to the anhydrous oligomer polyol, and under stirring, the catalyst is added dropwise, and the reaction is carried out at 80 to 85 ° C for 1 to 2 hours to obtain the first intermediate, wherein the oligomer polyol and the diisocyanate are mixed. The weight ratio of isocyanate is 18.64:20.87; Step 2, taking the total mass of oligomer polyol, diisocyanate, polyhydroxy carboxylic acid, small molecule diol monomer and crosslinking agent as the total amount, according to the weight ratio of KH-580 modified mica to the total amount At 6 to 14:50, the mica and the first intermediate are mixed and reacted with stirring to obtain the second intermediate; Step 3, cooling the second intermediate to 60-70° C., adding dry polyhydroxycarboxylic acid, and reacting for 2-3 hours to obtain the third intermediate; Step 4, drop a small molecule diol monomer into the third intermediate, and add an organic solvent to reduce the viscosity until the solution is colorless, heat up to 70-80 ° C, and react for 1-2 hours to obtain the fourth intermediate; In step 5, a cross-linking agent is added dropwise to the fourth intermediate, and the reaction is carried out at 60-70° C. for 2-3 hours to obtain the fifth intermediate; Step 6, cooling the fifth intermediate to 20-35° C., adding organic amine to neutralize and forming a salt under stirring, and reacting for 0.5-1 hour to obtain the sixth intermediate; Step 7, adding water to the sixth intermediate for shear emulsification, the shear speed is controlled at 2000-3000 r/min, the reaction is performed for 0.5-1 hour, and the organic solvent is removed by rotary evaporation to obtain a mica-modified aqueous polyurethane emulsion. 2. The preparation method according to claim 1, wherein in step 1, the number-average molecular weight of the oligomer polyol is 1000-4000, and the oligomer polyol is selected from the group consisting of polycaprolactone One or both of ester diol, polyhexylene adipate diol, polytetrahydrofuran diol, hydroxyl-terminated polybutadiene, hydroxyl-terminated polybutadiene-acrylonitrile, the diisocyanate Selected from norbornane diisocyanate, lysine diisocyanate, naphthalene diisocyanate, diphenylmethane-4,4'-diisocyanate, xylylene diisocyanate, cyclohexane diisocyanate, tetramethyl m-phenylene One or more of dimethylene diisocyanate and 2-methylpentane diisocyanate, and the catalyst is stannous octoate or dibutyltin dilaurate. 3. preparation method according to claim 1 is characterized in that, in step 2, the mass ratio of described diisocyanate, polyhydroxycarboxylic acid, small molecule diol, crosslinking agent is 20.87:3:3.05: 3.31. 4. The preparation method according to claim 1, wherein in step 3, the polyhydroxy carboxylic acid is selected from one or both of dimethylol propionic acid and dimethylol butyric acid. 5. preparation method according to claim 1, is characterized in that, in step 4, described small molecule diol monomer is selected from 2-methyl-2,4-pentanediol, TCD tricyclic diol , one or more of trimethylpentanediol, methylpropanediol, 1,6-hexanediol and neopentyl glycol; Described organic solvent is selected from the one in acetone, butanone, nitrogen methyl pyrrolidone or more. 6. preparation method according to claim 1 is characterized in that, in step 5, described crosslinking agent is selected from a kind of in triethanolamine, pentaerythritol and glycerol; In step 6, described organic amine is selected from Triethylamine or ammonia water, the molar ratio of the organic amine to the polyhydroxycarboxylic acid is 1:1. 7. The mica-modified aqueous polyurethane emulsion prepared according to any one of the preparation methods of claims 1 to 6. 8. a sizing agent, is characterized in that, in parts by weight, comprises the following components: 80-110 parts of the mica-modified water-based polyurethane emulsion of claim 7, 0.1 to 0.3 parts of water-based thickener, 0.15～0.25 parts of water-based leveling agent, 0.2 to 0.4 parts of water-based defoamer, 4 to 7 parts of plasticizer, 14 to 26 parts of talcum powder, 2 to 6 parts of titanium dioxide, 0.2 to 0.8 parts of fumed silica, 3 to 8 parts of water-based curing agent. 9. the preparation method of sizing agent according to claim 8, is characterized in that, comprises the following steps: 80-110 parts by weight of mica-modified water-based polyurethane emulsion are added with 0.1-0.3 parts by weight of water-based thickener, 0.15-0.25 parts by weight of water-based leveling agent, 0.2-0.4 parts by weight of water-based defoamer, and 4-7 parts by weight of plasticizer agent, 14-26 parts by weight of talc, 2-6 parts by weight of titanium dioxide and 0.2-0.8 parts by weight of fumed silica, and stir, add 3-8 parts by weight of aqueous curing agent, and stir for 10-20 minutes to obtain an adhesive. 10. preparation method according to claim 9 is characterized in that, described aqueous thickener is selected from a kind of in Borchi Gel LW44, Borchi Gel L75N, BENAQUA 4000, BENAQUA 1000, and described aqueous leveling agent is selected from the One of BYK-361N, BYK-359, BYK-356, BYK-350, the water-based defoamer is selected from BYK-019, BYK-021, BYK-024, BYK-093 and BYK-1730 A kind of, described plasticizer is selected from a kind of in dimethyl phthalate, diethyl phthalate and dibutyl phthalate, and described water-based curing agent is selected from water-based One of the isocyanate curing agents Desmodur DN, Bayhydur3100, Bayhydur XP2487/1, Bayhydur XP2547 and Bayhydur XP2451.