A one-component solvent-based polyurethane anti-counterfeiting pressure-sensitive adhesive, its preparation method and application

Abstract

The invention belongs to the technical field of polymer materials, and specifically relates to a one-component solvent-type polyurethane anti-counterfeiting pressure-sensitive adhesive and a preparation method and application thereof. The preparation method is as follows: after a polyether polyol and an antioxidant are mixed and dehydrated, a small molecule diol is added to mix and dissolve, and the temperature is lowered, and then a diisocyanate is added to react, and after the temperature is lowered, an amine chain extender is added to mix and react at a higher temperature, and after the reaction is completed, the temperature is lowered, and then a diisocyanate is added to mix and react at a higher temperature, and finally a monohydric alcohol is added to react, and the material is discharged to obtain a one-component solvent-type polyurethane pressure-sensitive adhesive. The advantages of the invention are that the raw materials are easily available, the reaction conditions are mild, and the process is simple and easy. The one-component polyurethane pressure-sensitive adhesive prepared by the invention has low viscosity, high stability, and good operability. It has good initial adhesion, high peel strength, and good heat resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a single-component solvent-based polyurethane anti-counterfeiting pressure-sensitive adhesive and a preparation method and application thereof. Background Art

[0002] At present, the pressure-sensitive adhesive used for anti-counterfeiting labels is acrylic adhesive, and the solvent contains harmful organic solvents such as xylene or toluene, which produces unpleasant odors during use and causes physical harm to operators. In addition, when the anti-counterfeiting label is heated to about 120°C, the 180° peel strength with the substrate is very low, far less than the standard requirement of 180° peel strength greater than 8N / 25mm. As a result, when the anti-counterfeiting label is peeled off at about 120°C, it cannot be destroyed and cannot play the role of product anti-counterfeiting. Some counterfeit products impact the market, causing negative impact on corporate image and reputation. Enterprises have used various adhesives, but have not been able to obtain satisfactory results. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a one-component solvent-based polyurethane anti-counterfeiting pressure-sensitive adhesive and a preparation method and application thereof.

[0004] The object of the present invention is achieved through the following technical scheme: A method for preparing a one-component polyurethane solvent-based pressure-sensitive adhesive comprises the following steps:

[0005] S1. Weigh the following raw materials by mass: 150-200 parts of polyether polyol, 48.2-68.3 parts of diisocyanate, 0.03-0.04 parts of organic bismuth catalyst, 0.15-0.2 parts of antioxidant, 7.5-10 parts of small molecule diol, 1.5-3 parts of amine chain extender, 4-6 parts of monohydric alcohol, and 300-410 parts of organic solvent;

[0006] S2, after mixing and dehydrating the raw material polyether polyol and antioxidant, adding a small molecule diol and mixing and dissolving to obtain product 1;

[0007] S3, 34.5-49.3 parts of diisocyanate are mixed with product 1, the temperature is raised to 80-90° C. for reaction, and then an organic bismuth catalyst and 90-120 parts of an organic solvent are added to continue the reaction to obtain product 2;

[0008] S4, mixing an amine chain extender with 90-120 parts of an organic solvent, and then adding the product 2 to react to obtain a product 3;

[0009] S5, mixing 13.7 to 19 parts of diisocyanate and 120 to 170 parts of an organic solvent, and reacting the mixture with the product three to obtain a product four;

[0010] S6. Mix the monohydric alcohol and the product four to react to obtain the one-component polyurethane solvent-based pressure-sensitive adhesive.

[0011] Furthermore, in step S2, the dehydration is vacuum dehydration; preferably, the vacuum dehydration conditions are gradually heated and stirred evenly, the temperature is raised to 105-110° C., dehydration is performed for 2 to 2.5 hours, and the vacuum degree is -0.08 to -0.085 MPa;

[0012] And / or, in step S3, before the diisocyanate is mixed with the product one, the product one needs to be cooled to 60-80°C; the temperature is raised to 80-90°C for reaction for 0.5-1h, and then the organic bismuth catalyst and the organic solvent are added to continue the reaction for 2-2.5h;

[0013] And / or, in step S4, before the reaction of product 2, the temperature needs to be lowered to 45-55°C; the time for adding product 2 is 0.5-1h, and the reaction temperature is 45-55°C;

[0014] And / or, in step S5, before the product 2 reacts, the temperature needs to be controlled at 45-55°C; the time for reacting with the product 3 is 2-3h, and after mixing, the temperature is gradually raised to 80-90°C;

[0015] And / or, in step S6, the time for mixing the monohydric alcohol and the product four to react is 0.5 to 1 hour.

[0016] Further, the polyether polyol is one or both of polytetramethylene glycol (PTMG), polyethylene glycol (PEG) and polypropylene glycol (PPG), preferably polypropylene glycol (PPG).

[0017] Further, the small molecule diol is methyl propylene glycol (MPD), ethylene glycol (EG), hexylene glycol (HDO), neopentyl glycol (NGP), 1,3-propylene glycol (PDO) and 1,4-butanediol (BDO). Preferably, the small molecule diol is 1,4-butanediol (BDO).

[0018] Furthermore, the diisocyanate is one or more of isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI) and toluene diisocyanate (TDI), preferably isophorone diisocyanate (IPDI).

[0019] Furthermore, the amine chain extender is one or more of ethylenediamine, butanediamine, pentanediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine and isophoronediamine, preferably diethylenetriamine.

[0020] Furthermore, the small molecule monohydric alcohol is one or more of ethanol, butanol and isopropanol, preferably isopropanol.

[0021] Furthermore, the organic solvent is ethyl acetate or dimethyl carbonate, preferably ethyl acetate; and / or the antioxidant is antioxidant 1010.

[0022] The present invention also provides the one-component polyurethane solvent-type pressure-sensitive adhesive prepared by the above preparation method.

[0023] The present invention also provides an application of the above-mentioned single-component polyurethane solvent-based pressure-sensitive adhesive in the bonding of anti-counterfeit labels.

[0024] The principle of the present invention is: after the reaction of polyether polyol, small molecule diol and isocyanate, the amount of residual isocyanate is controlled, and then amine reaction is performed to form urea bond, and isocyanate is added for a second reaction to increase the molecular weight of the polymer, enhance the peel strength and heat resistance of the pressure-sensitive adhesive, and finally monohydric alcohol is added for reaction and end-capping to obtain a single-component polyurethane anti-counterfeiting pressure-sensitive adhesive.

[0025] The beneficial effects of the present invention are:

[0026] 1. The one-component solvent-based polyurethane adhesive prepared by the present invention has good stability, can fully meet the production needs of the company's existing gluing production line, improve the working environment, protect the health of workers, has good bonding performance, good anti-counterfeiting effect, and the peel strength under high and low temperature conditions can meet the standard requirements.

[0027] 2. The raw materials of the present invention are easily available, the reaction conditions are mild, the process is simple and easy, and it is conducive to large-scale production and application. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described in detail below, but the protection scope of the present invention is not limited to the following.

[0029] Example 1

[0030] A method for preparing a one-component polyurethane solvent-based pressure-sensitive adhesive comprises the following steps:

[0031] S1. Weigh the following raw materials by mass: 175 parts of polypropylene glycol (PPG), 58 parts of isophorone diisocyanate (IPDI), 0.035 parts of organic bismuth catalyst, 0.175 parts of antioxidant 1010, 8.75 parts of 1,4-butanediol (BDO), 2.25 parts of diethylenetriamine, 5 parts of isopropanol, and 360 parts of ethyl acetate;

[0032] S2. Mix the raw material polypropylene glycol (PPG) and the antioxidant 1010 for vacuum dehydration, then add 1,4-butanediol (BDO) and mix and dissolve to obtain product 1; the vacuum dehydration conditions are as follows: gradually heat and stir evenly, raise the temperature to 107.5°C, dehydrate for 2.25h, and the vacuum degree is -0.0825MPa;

[0033] S3, cooling the product 1 to 70° C., mixing 41 parts of isophorone diisocyanate (IPDI) with the product 1, heating to 85° C. to react for 0.75 h, adding an organic bismuth catalyst and 110 parts of ethyl acetate to continue the reaction for 2.25 h, and obtaining the product 2;

[0034] S4, mixing an amine chain extender with 110 parts of ethyl acetate, and then adding product 2 to react for 0.75h (the product 2 was cooled to 50°C before the reaction), to obtain product 3;

[0035] S5, 17 parts of isophorone diisocyanate (IPDI) and 140 parts of ethyl acetate were mixed, and then mixed with product three, and then gradually heated to 85° C. to react for 2.5 hours to obtain product four;

[0036] S6. Mix the monohydric alcohol and the product four and react for 0.75 h to obtain the one-component polyurethane solvent-based pressure-sensitive adhesive.

[0037] Example 2-3

[0038] The difference between Example 2 and Example 1 is that the amounts of components are different. The amounts of components in Example 2 are as follows: 150 parts of polypropylene glycol (PPG), 48.2 parts of isophorone diisocyanate (IPDI), 0.04 parts of organic bismuth catalyst, 0.15 parts of antioxidant 1010, 7.5 parts of 1,4-butanediol (BDO), 1.5 parts of diethylenetriamine, 4 parts of isopropanol, and 300 parts of ethyl acetate;

[0039] Among them, the amount of isophorone diisocyanate (IPDI) added for the first time was 34.8 parts, the amount of isophorone diisocyanate (IPDI) added for the second time was 13.7 parts; the amount of ethyl acetate added for the first time was 90 parts, the amount of ethyl acetate added for the second time was 90 parts, and the amount of ethyl acetate added for the third time was 120 parts. The other experimental conditions were the same.

[0040] The difference between Example 3 and Example 1 is that the amounts of components are different. The amounts of components in Example 3 are as follows: 200 parts of polypropylene glycol (PPG), 68.3 parts of isophorone diisocyanate (IPDI), 0.03 parts of an organic bismuth catalyst, 0.2 parts of an antioxidant 1010, 10 parts of 1,4-butanediol (BDO), 3 parts of diethylenetriamine, 6 parts of isopropanol, and 410 parts of ethyl acetate;

[0041] Among them, the amount of isophorone diisocyanate (IPDI) added for the first time was 49.3 parts, the amount of isophorone diisocyanate (IPDI) added for the second time was 19 parts; the amount of ethyl acetate added for the first time was 120 parts, the amount of ethyl acetate added for the second time was 120 parts, and the amount of ethyl acetate added for the third time was 170 parts. The other experimental conditions were the same.

[0042] Embodiment 4-7

[0043] The difference between Example 4 and Example 1 is that some components are different. The polyether polyol of Example 4 is polytetrahydrofuran diol (PTMG), the small molecule diol is methyl propylene glycol (MPD), and the amine chain extender is ethylenediamine. The components of Example 4 are used in the following amounts: 175 parts of polytetrahydrofuran diol (PTMG), 58 parts of isophorone diisocyanate (IPDI), 0.035 parts of organic bismuth catalyst, 0.175 parts of antioxidant 1010, 8.75 parts of methyl propylene glycol (MPD), 2.0 parts of ethylenediamine, 5 parts of isopropyl alcohol, and 360 parts of ethyl acetate. The remaining experimental conditions are the same.

[0044] The difference between Example 5 and Example 1 is that some components are different. The small molecule diol in Example 5 is ethylene glycol (EG), and the amine chain extender is diaminodiamine. The amount of components in Example 5 is as follows: 175 parts of polypropylene glycol (PPG), 58 parts of isophorone diisocyanate (IPDI), 0.035 parts of organic bismuth catalyst, 0.175 parts of antioxidant 1010, 6.03 parts of ethylene glycol (EG), 2.88 parts of diaminodiamine, 5 parts of isopropanol, and 360 parts of ethyl acetate. The rest of the experimental conditions are the same.

[0045] The difference between Example 6 and Example 1 is that some components are different. The small molecule diol in Example 6 is ethylene glycol (EG), and the amine chain extender is pentamethylenediamine. The amount of components in Example 6 is as follows: 175 parts of polypropylene glycol (PPG), 43.9 parts of isophorone diisocyanate (IPDI), 0.035 parts of organic bismuth catalyst, 0.175 parts of antioxidant 1010, 6.03 parts of ethylene glycol (EG), 3.34 parts of pentamethylenediamine, 5 parts of isopropanol, and 360 parts of ethyl acetate. The rest of the experimental conditions are the same.

[0046] The difference between Example 7 and Example 1 is that some components are different. The small molecule diol in Example 7 is neopentyl glycol (NGP), the amine chain extender is triethylenetetramine, and the small molecule monohydric alcohol is ethanol. The amount of components in Example 7 is as follows: 175 parts of polypropylene glycol (PPG), 58 parts of isophorone diisocyanate (IPDI), 0.035 parts of organic bismuth catalyst, 0.175 parts of antioxidant 1010, 10.11 parts of neopentyl glycol (NGP), 2.4 parts of triethylenetetramine, 3.84 parts of ethanol, and 360 parts of ethyl acetate. The rest of the experimental conditions are the same.

[0047] Comparative Example 1

[0048] The difference between Comparative Example 1 and Example 1 is that the preparation method of Comparative Example 1 is different. In Comparative Example 1, steps S3 and S5 are combined, that is, all the isophorone diisocyanate (IPDI) in steps S3 and S5 are mixed with product 1 at one time for reaction, and the organic solvent is also combined and mixed with the organic bismuth catalyst and added, and the other experimental conditions are the same. However, after the reaction is completed, gelation occurs when the amine chain extender is added for reaction.

[0049] Experimental Example 1

[0050] The anti-counterfeiting pressure-sensitive adhesives prepared in Examples 1-7 were tested for peeling degree and peeling strength after high-temperature aging at multiple temperatures. The experimental method was based on GB / T2792-2014. The test results are shown in the following table:

[0051]

[0052]

[0053] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a one-component polyurethane solvent-based pressure-sensitive adhesive, characterized in that: The following steps are involved: S1. Weigh the following raw materials by mass: 150-200 parts of polyether polyol, 48.2-68.3 parts of diisocyanate, 0.03-0.04 parts of organic bismuth catalyst, 0.15-0.2 parts of antioxidant, 7.5-10 parts of small molecule diol, 1.5-3 parts of amine chain extender, 4-6 parts of monohydric alcohol, and 300-410 parts of organic solvent; S2, after mixing and dehydrating the raw material polyether polyol and antioxidant, adding a small molecule diol and mixing and dissolving to obtain product 1; S3, 34.5-49.3 parts of diisocyanate are mixed with product one, the temperature is raised to 80-90° C. for reaction, and then an organic bismuth catalyst and 90-120 parts of an organic solvent are added to continue the reaction to obtain product two; S4, mixing an amine chain extender with 90-120 parts of an organic solvent, and then adding the product 2 to react to obtain a product 3; S5, mixing 13.7 to 19 parts of diisocyanate and 120 to 170 parts of an organic solvent, and reacting the mixture with the product three to obtain a product four; S6, mixing the monohydric alcohol with the product four to obtain the one-component polyurethane solvent-based pressure-sensitive adhesive; The diisocyanate is isophorone diisocyanate.

2. The preparation method according to claim 1, characterized in that: In step S2, the dehydration is vacuum dehydration; And / or, in step S3, the temperature is raised to 80-90° C. for a reaction time of 0.5-1 h, and then the organic bismuth catalyst and the organic solvent are added to continue the reaction time of 2-2.5 h; and / or, in step S4, the time for adding product 2 is 0.5 to 1 hour; and / or, in step S5, the time for reacting with product 3 is 2 to 3 hours; And / or, in step S6, the time for mixing the monohydric alcohol and the product four to react is 0.5 to 1 hour.

3. The preparation method according to claim 1, characterized in that: The polyether polyol is one or two of polytetrahydrofuran diol, polyethylene glycol and polypropylene glycol.

4. The preparation method according to claim 1, characterized in that: The small molecule diols are methyl propylene glycol, ethylene glycol, hexylene glycol, neopentyl glycol, 1,3-propylene glycol and 1,4-butanediol.

5. The preparation method according to claim 1, characterized in that: The amine chain extender is one or more of ethylenediamine, butanediamine, pentanediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine and isophoronediamine.

6. The preparation method according to claim 1, characterized in that: The monohydric alcohol is one or more of ethanol, butanol and isopropanol.

7. The preparation method according to claim 1, characterized in that: The organic solvent is ethyl acetate or dimethyl carbonate; and / or the antioxidant is antioxidant 1010.

8. The one-component polyurethane solvent-based pressure-sensitive adhesive prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the one-component polyurethane solvent-based pressure-sensitive adhesive according to claim 8 in bonding anti-counterfeit labels.

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