CN113549421B

CN113549421B - Waterborne polyurethane adhesive and preparation method thereof

Info

Publication number: CN113549421B
Application number: CN202110788169.8A
Authority: CN
Inventors: 鲁岗; 王甫俊
Original assignee: Wenzhou Dabao Macromolecule Material Co ltd
Current assignee: Wenzhou Dabao Macromolecule Material Co ltd
Priority date: 2021-07-13
Filing date: 2021-07-13
Publication date: 2022-10-21
Anticipated expiration: 2041-07-13
Also published as: CN113549421A

Abstract

The application relates to a waterborne polyurethane adhesive and a preparation method thereof, and the waterborne polyurethane adhesive comprises the following raw materials in parts by weight: 25-30 parts of polytetrahydrofuran ether glycol, 8-15 parts of isophorol diisocyanate, 0.8-1.2 parts of 1, 4-butanediol, 1-2 parts of dimethylolpropionic acid, 1-1.5 parts of triethylamine, 0.2-0.5 part of ethylenediamine, 10-15 parts of diethylformamide, 5-7 parts of undeceneamide, 2-3 parts of pentaerythritol tetramercaptoacetate, 0.2-0.3 part of a crosslinking agent and 50-60 parts of deionized water; a preparation method of a water-based polyurethane adhesive comprises the steps of preparing matrix polyurethane; mixing a matrix polyurethane with the undeceneamide and pentaerythritol tetramercaptoacetate crosslinked product. In the application, linear undeceneamide and pentaerythritol tetramercapto-acetic ester generate a crosslinking reaction to form a compact winding structure to obtain a tough network crosslinking substance, and the tough network crosslinking substance is further mixed with matrix polyurethane, so that the strain-induced crystallization tendency is promoted, and better initial adhesion and mechanical properties are obtained.

Description

Waterborne polyurethane adhesive and preparation method thereof

Technical Field

The application relates to the technical field of adhesives, in particular to a water-based polyurethane adhesive and a preparation method thereof.

Background

Polyurethane (PU) adhesives are adhesives containing urethane groups (-NHCOO-) or isocyanate groups (-NCO) in the molecular chain, and can be classified into two major classes, polyisocyanate and polyurethane. Because the polyurethane adhesive contains the two groups and shows higher activity and polarity, the polyurethane adhesive is applied to a plurality of substrates, such as porous materials of foam, plastic, wood, leather, fabric, paper, ceramic and the like, and materials with smooth surfaces of metal, glass, rubber, plastic and the like, and has excellent adhesive force; however, the current aqueous polyurethane adhesives have a problem of low initial tack and are still to be further improved.

Disclosure of Invention

In order to improve the initial viscosity of the polyurethane adhesive, the application provides a water-based polyurethane adhesive and a preparation method thereof.

In a first aspect, the application provides a water-based polyurethane adhesive, which adopts the following technical scheme:

the waterborne polyurethane adhesive comprises the following raw materials in parts by weight:

25-30 parts of polytetrahydrofuran ether glycol;

8-15 parts of isophorol diisocyanate;

0.8-1.2 parts of 1, 4-butanediol;

1-2 parts dimethylolpropionic acid;

1-1.5 parts of triethylamine;

0.2-0.5 parts of ethylenediamine;

10-15 parts of diethylformamide;

5-7 parts of undeceneamide;

2-3 parts of pentaerythritol tetramercaptoacetate;

0.2-0.3 part of a crosslinking agent;

50-60 parts of deionized water.

By adopting the technical scheme, the linear chain molecule undeceneamide and the pentaerythritol tetrasulfamoyl acetate generate a crosslinking reaction, a compact winding structure can be formed, a tough network crosslinking substance is obtained, the tendency of promoting strain induced crystallization is realized, and better initial viscosity and mechanical property are obtained; the matrix polyurethane obtained by the reaction is further mixed with a cross-linking substance, so that the cohesive force of a glue layer of the polyurethane adhesive can be improved, and the initial adhesion and the bonding strength are further effectively improved.

Preferably, the weight part ratio of the undeceneamide to the pentaerythritol tetramercapto-acetate is 3.

By adopting the technical scheme, experiments prove that when the weight part ratio of the undecene amide to the pentaerythritol tetramercapto acetic ester is 3.

Preferably, the raw material also comprises 0.1 to 0.2 part of N-methoxymethyl amine by weight.

By adopting the technical scheme, a proper amount of N-methoxymethyl amine is added to improve the reaction activity of pentaerythritol tetramercapto acetic ester, the higher the activity is, the faster the reaction speed is, and the higher the crosslinking density is, which is beneficial to further improving the initial viscosity and the bonding strength.

Preferably, the raw material also comprises 5-6 parts of 1, 6-hexanediol diglycidyl ether by weight.

By adopting the technical scheme, the addition of the 1, 6-hexanediol diglycidyl ether can increase the hydroxyl content and improve the crystallinity, so that the initial viscosity of the matrix polyurethane can be improved to a certain extent; and the 1, 6-hexanediol diglycidyl ether has small molecular volume and easy diffusion, can permeate into a bonded material, and achieves the aim of improving the adhesive force.

Preferably, the raw materials also comprise 1-2 parts of epoxybutene and 0.4-0.6 part of di (propylene glycol) butyl ether by weight.

By adopting the technical scheme, the di (propylene glycol) butyl ether and the epoxy compound epoxybutene react to obtain a product which can improve the compatibility of all components during blending and increase the interfacial adhesion, thereby improving the initial viscosity and the adhesion strength of the polyurethane adhesive.

Preferably, the crosslinking agent is 2-ethylimidazole.

By adopting the technical scheme, compared with the benzoyl peroxide, the 2-ethylimidazole adopted as the cross-linking agent can improve the initial viscosity and the bonding strength of the polyurethane adhesive to a certain extent.

In a second aspect, the present application provides a method for preparing a water-based polyurethane adhesive, which adopts the following technical scheme:

a preparation method of a water-based polyurethane adhesive comprises the following steps:

s1, dehydrating polytetrahydrofuran ether glycol for 1-1.5h at 100-120 ℃ and under the condition that the vacuum degree is less than or equal to-0.8 MPa; adding 1, 4-butanediol, isophorone diisocyanate and 0.2-0.3 part of catalyst at 80-90 ℃, and reacting for 3-4h; cooling to 50-60 ℃, adding 7-10 parts of dimethylolpropionic acid dissolved in diethylformamide, reacting for 4-5h under heat preservation, stirring and adding the rest diethylformamide; cooling to less than or equal to 50 ℃, and then adding triethylamine to react for 8-10min; stirring at the rotating speed of 700-800r/min, adding deionized water, adding ethylenediamine, and stirring to obtain matrix polyurethane;

s2, stirring and mixing the cross-linking agent and the undecylenic amide for 5-8min, heating to 70-80 ℃, continuously adding pentaerythritol tetramercaptoacetate, and stirring for reacting for 1-2h to obtain a cross-linked product; finally, the cross-linked product and the matrix polyurethane are mixed and stirred for 40-50min.

By adopting the technical scheme, 1, 4-butanediol is used as a chain extender, the diethylformamide is added twice, and the diethylformamide added for the second time has a viscosity reducing effect, so that the components are more compatible.

Preferably, the method further comprises the following steps:

after matrix polyurethane is obtained in the S1, adding 1, 6-hexanediol diglycidyl ether, and stirring for 15-20min;

mixing epoxybutene and di (propylene glycol) butyl ether, heating to 50-60 ℃, and stirring for 30-40min to obtain a blending component;

mixing pentaerythritol tetramercaptoacetate and N-methoxymethyl amine, and stirring for 15-20min;

in the S2, stirring and mixing the cross-linking agent and the undecenamide for 5-8min, heating to 70-80 ℃, continuously adding a mixture of pentaerythritol tetramercaptoacetate and N-methoxymethyl amine, and stirring for reacting for 1-2h to obtain a cross-linked product; finally, blending the crosslinking product and matrix polyurethane mixed with 1, 6-hexanediol diglycidyl ether, and stirring at 60-65 ℃ for 40-50min; finally adding the blending component, preserving the temperature and stirring for 30-40min.

To sum up, the application comprises the following beneficial technical effects:

1. the linear chain molecule undeceneamide and pentaerythritol tetrasulfamoyl acetate generate a crosslinking reaction, a compact winding structure can be formed, a tough network crosslinking substance is obtained, the tendency of promoting strain induced crystallization is realized, and better initial viscosity and mechanical property are obtained; the matrix polyurethane obtained by the reaction is further mixed with a cross-linked substance, so that the cohesive force of a glue layer of the polyurethane adhesive can be improved, and the initial adhesion and the bonding strength are further effectively improved;

2. when the weight part ratio of the undeceneamide to the pentaerythritol tetramercapto acetate is 3;

the N-methoxymethyl amine improves the reactivity of pentaerythritol tetramercapto acetic ester, and the higher the activity is, the faster the reaction speed is, the higher the crosslinking density is, thus being beneficial to further improving the initial viscosity and the bonding strength;

4. the di (propylene glycol) butyl ether and epoxy compound epoxybutene react to obtain a product which can improve the compatibility of all components during blending and increase the interface bonding force, so that the initial viscosity and the bonding strength of the polyurethane adhesive are improved;

the addition of 1, 6-hexanediol diglycidyl ether can increase the hydroxyl content and improve the crystallinity, thereby improving the initial tack of the matrix polyurethane to a certain extent; and the 1, 6-hexanediol diglycidyl ether has small molecular volume and easy diffusion, can permeate into the bonded material and achieves the purpose of improving the adhesive force.

Detailed Description

The present application is described in further detail below.

In this application, polytetrahydrofuran ether glycol is available from Xiaooxing Korea; isophorol diisocyanate was purchased from knifing, germany; 1, 4-butanediol was purchased from Mitsubishi, japan; dimethylolpropionic acid was purchased from Jiangxi Jiyu New materials Co., ltd; triethylamine, ethylenediamine and diethylformamide are all purchased from Shanghai Bai chemical Co., ltd; 1, 6-hexanediol diglycidyl ether is available from Zhejiang Bomo New materials, inc.; in the application, stannous octoate is used as the catalyst.

The raw materials used in the following embodiments may be those conventionally commercially available unless otherwise specified.

Examples

Example 1

The application discloses a water-based polyurethane adhesive, which comprises the following raw materials:

polytetrahydrofuran ether glycol, isophorol diisocyanate, 1, 4-butanediol, dimethylolpropionic acid, triethylamine, ethylenediamine, diethylformamide, undeceneamide, pentaerythritol tetramercaptoacetate, a crosslinking agent and deionized water; wherein the cross-linking agent is 2-ethylimidazole.

s1, dehydrating polytetrahydrofuran ether glycol for 1h at 100 ℃ and under the condition that the vacuum degree is less than or equal to-0.8 MPa; adding 1, 4-butanediol, isophorol diisocyanate and 0.2 part of catalyst stannous octoate at 80 ℃ to react for 3 hours; cooling to 50 ℃, adding 7 parts of dimethylolpropionic acid dissolved in diethyl formamide, reacting for 4 hours under heat preservation, stirring, and adding the rest diethyl formamide; cooling to less than or equal to 50 ℃, and then adding triethylamine to react for 8min; stirring at the rotating speed of 100r/min, adding deionized water, adding ethylenediamine, and stirring to obtain matrix polyurethane;

s2, stirring and mixing the cross-linking agent and the undecylenic amide for 5min, heating to 70 ℃, continuously adding pentaerythritol tetramercaptoacetate, and stirring for reacting for 1h to obtain a cross-linked product; finally, the cross-linked product and the matrix polyurethane are mixed and stirred for 40min.

The contents of the components are shown in table 1 below.

Example 2

s1, dehydrating polytetrahydrofuran ether glycol for 1.5h at 120 ℃ under the condition that the vacuum degree is less than or equal to-0.8 MPa; adding 1, 4-butanediol, isophorol diisocyanate and 0.3 part of catalyst stannous octoate at 90 ℃ to react for 4 hours; cooling to 60 ℃, adding 10 parts of dimethylolpropionic acid dissolved in diethylformamide, reacting for 5 hours under heat preservation, stirring and adding the rest diethylformamide; cooling to less than or equal to 50 ℃, and then adding triethylamine to react for 10min; stirring at the rotating speed of 200r/min, adding deionized water, adding ethylenediamine, and stirring to obtain matrix polyurethane;

s2, stirring and mixing the cross-linking agent and the undecylenic amide for 8min, heating to 80 ℃, continuously adding pentaerythritol tetramercaptoacetate, and stirring for reacting for 2h to obtain a cross-linked product; and finally, mixing the cross-linked product with the matrix polyurethane, and stirring for 50min.

The contents of the components are shown in table 1 below.

Example 3

s1, dehydrating polytetrahydrofuran ether glycol for 1.2h at the temperature of 110 ℃ and the vacuum degree of less than or equal to-0.8 MPa; adding 1, 4-butanediol, isophorol diisocyanate and 0.3 part of catalyst stannous octoate at 85 ℃ to react for 3.5h; cooling to 55 ℃, adding 8 parts of dimethylolpropionic acid dissolved in diethyl formamide, reacting for 4.5 hours under the condition of heat preservation, stirring and adding the rest diethyl formamide; cooling to less than or equal to 50 ℃, and then adding triethylamine to react for 9min; stirring at the rotating speed of 150r/min, adding deionized water, adding ethylenediamine, and stirring to obtain matrix polyurethane;

s2, stirring and mixing the cross-linking agent and the undecylenic amide for 6min, heating to 75 ℃, continuously adding pentaerythritol tetramercaptoacetate, and stirring to react for 1.5h to obtain a cross-linked product; and finally, mixing the cross-linked product with the matrix polyurethane, and stirring for 45min.

The contents of the components are shown in table 1 below.

Example 4

polytetrahydrofuran ether glycol, isophorol diisocyanate, 1, 4-butanediol, dimethylolpropionic acid, triethylamine, ethylenediamine, diethylformamide, undeceneamide, pentaerythritol tetramercaptoacetate, a crosslinking agent, deionized water, N-methoxymethylamine, 1, 6-hexanediol diglycidyl ether, epoxybutene, di (propyleneglycol) butyl ether; wherein the cross-linking agent is 2-ethylimidazole.

s1, dehydrating polytetrahydrofuran ether glycol for 1h at 100 ℃ and under the condition that the vacuum degree is less than or equal to-0.8 MPa; adding 1, 4-butanediol, isophorol diisocyanate and 0.2 part of catalyst stannous octoate at 80 ℃ to react for 3 hours; cooling to 50 ℃, adding 7 parts of dimethylolpropionic acid dissolved in diethylformamide, reacting for 4 hours under heat preservation, stirring and adding the rest diethylformamide; cooling to less than or equal to 50 ℃, and then adding triethylamine to react for 8min; stirring at the rotating speed of 100r/min, adding deionized water, adding ethylenediamine, and stirring to obtain matrix polyurethane; adding 1, 6-hexanediol diglycidyl ether, and stirring for 15min;

s2, mixing epoxybutene and di (propylene glycol) butyl ether, heating to 50 ℃, and stirring for 30min to obtain a blending component;

pentaerythritol tetramercaptoacetate and N-methoxymethyl amine are mixed and stirred for 15min;

stirring and mixing the cross-linking agent and the undecylenic amide for 5min, heating to 70 ℃, continuously adding a mixture of pentaerythritol tetramercapto-acetic ester and N-methoxymethyl amine, and stirring for reacting for 1h to obtain a cross-linked product; finally, mixing the cross-linked product with the matrix polyurethane, and stirring for 40min; finally adding the blending components, preserving the temperature and stirring for 30min.

The contents of the components are shown in table 1 below.

Example 5

s1, dehydrating polytetrahydrofuran ether glycol for 1.5h at 120 ℃ and under the condition that the vacuum degree is less than or equal to-0.8 MPa; adding 1, 4-butanediol, isophorol diisocyanate and 0.3 part of catalyst stannous octoate at 90 ℃ to react for 4 hours; cooling to 60 ℃, adding 10 parts of dimethylolpropionic acid dissolved in diethylformamide, reacting for 5 hours under heat preservation, stirring and adding the rest diethylformamide; cooling to less than or equal to 50 ℃, and then adding triethylamine to react for 10min; stirring at the rotating speed of 200r/min, adding deionized water, adding ethylenediamine, and stirring to obtain matrix polyurethane; adding 1, 6-hexanediol diglycidyl ether, and stirring for 20min;

s2, mixing epoxybutene and di (propylene glycol) butyl ether, heating to 60 ℃, and stirring for 40min to obtain a blending component;

pentaerythritol tetramercaptoacetate and N-methoxymethyl amine are mixed and stirred for 20min;

stirring and mixing the cross-linking agent and the undecylenic amide for 8min, heating to 80 ℃, continuously adding a mixture of pentaerythritol tetramercaptoacetate and N-methoxymethyl amine, and stirring for reacting for 2h to obtain a cross-linked product; finally, mixing the cross-linked product with the matrix polyurethane, and stirring for 50min; finally adding the blending components, preserving the temperature and stirring for 40min.

The contents of the components are shown in table 1 below.

Example 6

s1, dehydrating polytetrahydrofuran ether glycol for 1.2h at 110 ℃ under the condition that the vacuum degree is less than or equal to-0.8 MPa; adding 1, 4-butanediol, isophorol diisocyanate and 0.3 part of catalyst stannous octoate at 85 ℃ to react for 3.5h; cooling to 55 ℃, adding 8 parts of dimethylolpropionic acid dissolved in diethyl formamide, reacting for 4.5 hours under the condition of heat preservation, stirring and adding the rest diethyl formamide; cooling to less than or equal to 50 ℃, and then adding triethylamine to react for 9min; stirring at the rotating speed of 150r/min, adding deionized water, adding ethylenediamine, and stirring to obtain matrix polyurethane; then adding 1, 6-hexanediol diglycidyl ether, and stirring for 17min;

s2, mixing epoxybutene and di (propylene glycol) butyl ether, heating to 55 ℃, and stirring for 35min to obtain a blending component;

mixing pentaerythritol tetramercaptoacetate and N-methoxymethyl amine and stirring for 17min;

stirring and mixing the cross-linking agent and the undecylenic amide for 6min, heating to 75 ℃, continuously adding a mixture of pentaerythritol tetramercaptoacetate and N-methoxymethyl amine, and stirring for reacting for 1.5h to obtain a cross-linked product; finally, mixing the cross-linked product with matrix polyurethane, and stirring for 45min; finally, adding the blending components, preserving the temperature and stirring for 35min.

The contents of the components are shown in table 1 below.

Example 7

The difference from example 1 is that the raw material components of the aqueous polyurethane adhesive also include N-methoxymethyl amine, and the content of each component is shown in Table 2 below.

Example 8

The difference from example 7 is that N-methoxymethyl amine was replaced with diisopropylamine, and the contents of the respective components are shown in Table 2 below.

Example 9

The difference from example 1 is that N-methoxymethylamine and pentaerythritol tetramercaptoacetate were not added and the contents of the respective components are shown in Table 2 below.

Example 10

The difference from example 1 is that the raw material components of the aqueous polyurethane adhesive further include 1, 6-hexanediol diglycidyl ether, and the content of each component is shown in table 2 below.

Example 11

The difference from example 10 is that 1, 6-hexanediol diglycidyl ether was replaced with diethyl ether, and the contents of the components are shown in Table 2 below.

Example 12

The difference from example 1 is that the raw material components of the aqueous polyurethane adhesive further include epoxybutene and di (trimethylene glycol) butyl ether, and the content of each component is shown in table 2 below.

Example 13

The difference from example 12 is that epoxybutene was replaced with 1-butene, and the contents of the respective components are shown in Table 2 below.

Example 14

The difference from example 12 is that the di (trimethylene glycol) butyl ether is replaced with isobutyl vinyl ether and the amounts of the components are shown in table 2 below.

Example 15

The difference from example 1 is that benzoyl peroxide is used as the crosslinking agent.

Example 16

The difference from example 1 is that the ratio of undeceneamide to pentaerythritol tetramercapto acetic acid was 3 parts by weight, and the contents of the respective components are shown in table 2 below.

Comparative example

Comparative example 1

Example 1 of chinese patent publication No. CN103421462A was used as comparative example 1.

Comparative example 2

The difference from example 1 is that the undeceneamide was replaced with dimethylformamide and the contents of the components are as shown in table 1 below.

Comparative example 3

The difference from example 1 is that pentaerythritol tetramercaptoacetate was replaced with ethyl acetate and the contents of the components are shown in table 1 below.

Comparative example 4

The difference from example 1 is that undeceneamide and pentaerythritol tetramercaptoacetate were not added and the contents of the components are shown in Table 1 below.

TABLE 1 component content tables of examples 1 to 6 and comparative examples 2 to 4

	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Comparative example 2	Comparative example 3	Comparative example 4
										Polytetrahydrofuran ether glycol	25	30	28	25	30	28	25	25	25
Isoversol diisocyanate	8	15	12	8	15	12	8	8	8
										1, 4-butanediol	0.8	1.2	1.0	0.8	1.2	1.0	0.8	0.8	0.8
Dimethylolpropionic acid	1	2	1.5	1	2	1.5	1	1	1
										Triethylamine	1	1.5	1.2	1	1.5	1.2	1	1	1
Ethylenediamine	0.2	0.5	0.4	0.2	0.5	0.4	0.2	0.2	0.2
										Diethyl formamide	10	15	13	10	15	13	10	10	10
Undeceneamide/dimethylformamide	5	7	6	5	7	6	5	5	/
										Pentaerythritol Tetramercaptoacetate/Ethyl acetate	2	3	3	2	3	3	2	2	/
Crosslinking agent	0.2	0.3	0.3	0.2	0.3	0.3	0.2	0.2	0.2
										Deionized water	50	60	55	50	60	55	50	50	50
N-methoxymethyl amine	/	/	/	0.1	0.2	0.2	/	/	/
										1, 6-hexanediol diglycidyl ether	/	/	/	5	6	5.5	/	/	/
Epoxybutene	/	/	/	1	2	1.5	/	/	/
										Bis (trimethylene glycol) butyl ether	/	/	/	0.4	0.6	0.5	/	/	/

TABLE 2 component content tables for examples 7-14 and example 16

	Example 7	Example 8	Example 9	Example 10	Example 11	Example 12	Example 13	Example 14	Example 16
										Polytetrahydrofuran ether glycols	25	25	25	25	25	25	25	25	25
Isoversol diisocyanate	8	8	8	8	8	8	8	8	8
										1, 4-butanediol	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8
Dimethylolpropionic acid	1	1	1	1	1	1	1	1	1
										Triethylamine	1	1	1	1	1	1	1	1	1
Ethylenediamine	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
										Diethyl formamide	10	10	10	10	10	10	10	10	10
Undeceneamides	5	5	5	5	5	5	5	5	6
										Pentaerythritol Tetramercaptoacetate	2	2	/	2	2	2	2	2	2
Crosslinking agent	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
										Deionized water	50	50	50	50	50	50	50	50	50
N-methoxymethylamine/diisopropylamine	0.1	0.1	/	/	/	/	/	/	/
										1, 6-hexanediol diglycidyl ether/diethyl ether	/	/	/	5	5	/	/	/	/
Epoxybutene/1-butene	/	/	/	/	/	1	1	1	/
										Bis (trimethylene glycol) butyl ether/isobutyl vinyl ether	/	/	/	/	/	0.4	0.4	0.4	/

Performance test

The bonding strength is characterized by the peel strength; reference is made to GB/T2791-1995, adhesive T peel strength test method for initial adhesion and peel strength, wherein the initial adhesion is tested 2min after sample adhesion, and the peel strength is tested 24h after adhesion; the test results are shown in table 3 below.

TABLE 3 table of results of performance test of each example and comparative example

	Initial tack (PVC/PVC, N/mm)	Peel strength (PVC/PVC, N/mm)
			Example 1	2.1	4.9
Example 2	2.4	5.2
			Example 3	2.2	5.1
Example 4	2.6	5.4
			Example 5	2.9	5.8
Example 6	2.7	5.5
			Example 7	2.4	5.2
Example 8	2.0	4.9
			Example 9	1.7	4.4
Example 10	2.3	5.0
			Example 11	2.1	4.9
Example 12	2.5	5.3
			Example 13	2.2	5.0
Example 14	2.2	5.0
			Example 15	2.0	4.8
Example 16	2.3	5.1
			Comparative example 1	1.9	4.6
Comparative example 2	1.8	4.4
			Comparative example 3	1.9	4.6
Comparative example 4	1.7	4.3

In summary, the following conclusions can be drawn:

1. according to the results of examples 1 and 7 to 9 in combination with comparative example 3 and table 3, it can be seen that the addition of N-methoxymethylamine in the present application produces a synergistic effect with pentaerythritol tetramercaptoacetate to improve the initial tack and adhesive strength of the polyurethane adhesive.

2. As can be seen from examples 1 and 10 to 11 in combination with Table 3, the addition of 1, 6-hexanediol diglycidyl ether can improve the initial tack of the polyurethane adhesive to some extent, probably because of the increased hydroxyl content, which is beneficial to improving the crystallinity and thus increasing the viscosity.

3. As can be seen from examples 1 and 12-14 in combination with Table 3, the co-addition of di (trimethylene glycol) butyl ether and the epoxy epoxybutene provides a synergistic effect which contributes to the improvement of initial tack and bond strength of the polyurethane adhesive; the reason for this is probably that the reaction product of the two improves the compatibility when the components are blended, increasing the interfacial adhesion.

4. As can be seen from examples 1 and 15 in combination with Table 3, the initial tack and adhesive strength of the polyurethane adhesive are improved to some extent by using 2-ethylimidazole as the crosslinking agent as compared with benzoyl peroxide.

5. As can be seen from example 1 and example 16 in combination with table 3, when the weight part ratio of undeceneamide to pentaerythritol tetramercapto-acetate is 3.

6. According to example 1 and comparative example 1, and in combination with Table 3, the polyurethane adhesive prepared by the method has higher initial tack and bonding strength.

7. According to example 1, comparative examples 2-4 and Table 3, the undeceneamide and pentaerythritol tetramercaptoacetate have synergistic effect, and the initial adhesion and the bonding strength of the polyurethane adhesive can be improved by adding the undeceneamide and the pentaerythritol tetramercaptoacetate together.

The present embodiment is only for explaining the present application, and the scope of protection of the present application is not limited thereby, and those skilled in the art can make modifications to the present embodiment as necessary without inventive contribution after reading the present specification, but all are protected by patent law within the scope of the claims of the present application.

Claims

1. A waterborne polyurethane adhesive is characterized in that: the raw materials comprise the following components in parts by weight:

25-30 parts of polytetrahydrofuran ether glycol;

8-15 parts of isophorone diisocyanate;

0.8-1.2 parts of 1, 4-butanediol;

1-2 parts dimethylolpropionic acid;

1-1.5 parts of triethylamine;

0.2-0.5 parts of ethylenediamine;

10-15 parts of diethylformamide;

5-7 parts of undeceneamide;

2-3 parts of pentaerythritol tetramercaptoacetate;

0.2-0.3 part of a crosslinking agent;

50-60 parts of deionized water.

2. The aqueous polyurethane adhesive of claim 1, wherein: the weight part ratio of the undeceneamide to the pentaerythritol tetramercaptoacetate is 3.

3. The aqueous polyurethane adhesive of claim 1, wherein: the raw material also comprises 0.1 to 0.2 portion of N-methoxymethyl amine according to the weight portion.

4. The aqueous polyurethane adhesive of claim 1, wherein: the raw material also comprises 5-6 parts of 1, 6-hexanediol diglycidyl ether by weight.

5. The aqueous polyurethane adhesive of claim 1, wherein: the raw materials also comprise 1-2 parts of epoxybutene and 0.4-0.6 part of di (propylene glycol) butyl ether according to parts by weight.

6. The aqueous polyurethane adhesive of claim 1, wherein: the cross-linking agent is 2-ethylimidazole.

7. The method for preparing the aqueous polyurethane adhesive of claim 1, comprising the steps of:

s1, dehydrating polytetrahydrofuran ether glycol for 1-1.5h at 100-120 ℃ and under the condition that the vacuum degree is less than or equal to-0.8 MPa; adding 1, 4-butanediol, isophorone diisocyanate and 0.2-0.3 part of catalyst at 80-90 ℃, and reacting for 3-4h; cooling to 50-60 ℃, adding 7-10 parts of dimethylolpropionic acid dissolved in diethylformamide, reacting for 4-5h under heat preservation, stirring and adding the rest diethylformamide; cooling to less than or equal to 50 ℃, and then adding triethylamine to react for 8-10min; stirring at the rotating speed of 100-200r/min, adding deionized water, adding ethylenediamine, and stirring to obtain matrix polyurethane;

8. The method for preparing the aqueous polyurethane adhesive according to claim 7, wherein: also comprises the following steps:

after matrix polyurethane is obtained in the S1, adding 5-6 parts of 1, 6-hexanediol diglycidyl ether, and stirring for 15-20min;

mixing 1-2 parts of epoxybutene and 0.4-0.6 part of di (propylene glycol) butyl ether, heating to 50-60 ℃, and stirring for 30-40min to obtain a blending component;

mixing 2-3 parts of pentaerythritol tetramercaptoacetate and 0.1-0.2 part of N-methoxymethyl amine, and stirring for 15-20min;

in the S2, 0.2-0.3 part of cross-linking agent and 5-7 parts of undecylenic amide are stirred and mixed for 5-8min, the temperature is raised to 70-80 ℃, the mixture of pentaerythritol tetramercaptoacetate and N-methoxymethyl amine is continuously added, and the stirring reaction is carried out for 1-2h, so as to obtain a cross-linked product; finally, blending the crosslinking product and matrix polyurethane mixed with 1, 6-hexanediol diglycidyl ether, and stirring at 60-65 ℃ for 40-50min; finally adding the blending component, preserving the temperature and stirring for 30-40min.