CN106589310B - Water-based polyurethane emulsion for heat-resistant transfer coating and preparation method thereof - Google Patents

Abstract

The invention discloses a waterborne polyurethane emulsion for a temperature-resistant transfer coating and a preparation method thereof, and the key points of the technical scheme are as follows: the material composition comprises the following components in parts by weight: 6-14% of oligomer polyol, 10-14.2% of diisocyanate, 1.2-1.6% of hydrophilic chain extender, 1.5-3% of cross-linking agent, 16-18% of acetone, 2-4% of NMP, 4.0-4.5% of amine chain extender, 0.006-0.010% of catalyst, 43.69-51.49% of ice pure water and 0.8-1.2% of neutralizer. The invention provides the aqueous polyurethane emulsion for the temperature-resistant transfer coating, which has good transferability and good temperature resistance on the premise of not increasing the cost of raw materials by using main raw materials such as low polymer polyol, diisocyanate, a hydrophilic chain extender, a cross-linking agent, an amine chain extender and the like and using a two-step method of a prepolymer method.

Description

Water-based polyurethane emulsion for heat-resistant transfer coating and preparation method thereof

【Technical field】

The invention relates to a water-based polyurethane emulsion for a temperature-resistant transfer coating and a preparation method thereof, belonging to the technical field of coatings.

【Background technique】

By coating a layer of solvent-based transfer coating on PET, then aluminized, and then transferred to paper through water-based wet compound glue, this used to be a huge reform in the cigarette pack industry, because it is more efficient than directly aluminized on PET. Environmentally friendly and easier to degrade. However, in recent years, due to the increasingly stringent domestic environmental protection regulations, solvent-based transfer coatings are more and more restricted due to large VOC emissions, strong odor, and inflammability and explosion. Therefore, the trend of requiring water-based is becoming more and more obvious, but at present, two kinds of water-based products are mainly used to replace solvent-based transfer coatings on the market. One way is to replace solvent-based transfer coatings with water-based polyurethane-based water-based transfer coatings. However, the water-based transfer coating with water-based acrylic emulsion as the linking material has good printability and good temperature resistance, but the stripping property is not good; the water-based transfer coating with water-based polyurethane as the linking material has good stripping property and poor temperature resistance.

【Content of invention】

The purpose of the present invention is to use the main raw materials such as oligomer polyol, diisocyanate, hydrophilic chain extender, cross-linking agent and amine chain extender, with the two-step method of prepolymer method, without increasing the cost of raw materials On the premise, a water-based polyurethane emulsion for a temperature-resistant transfer coating with good transferability and good temperature resistance is provided.

Another object of the present invention is to provide a method for preparing a water-based polyurethane emulsion for heat-resistant transfer coatings.

A water-based polyurethane emulsion for heat-resistant transfer coatings, comprising the composition of the following weight components:

Preferably, the oligomer polyol is any one of polycarbonate diol (PCDL), neopentyl glycol adipate diol (PNA), and polytetrahydrofuran ether diol (PTMG).

Preferably, the diisocyanate is any one of H12MDI and IPDI.

Preferably, the hydrophilic chain extender is any one of dimethylolpropionic acid (DMPA) and dihydroxybutyric acid.

Preferably, the crosslinking agent is a mixture of trimethylolpropane, CHDM and BEPD.

Preferably, the catalyst is stannous octoate.

Preferably, the amine chain extender is a solution obtained by dissolving DMEA in 3% ice pure water, and the ice pure water is water at 0-4°C.

Preferably, the neutralizing agent is any one of triethylamine and hexamethylenediamine.

A preparation method of water-based polyurethane emulsion for heat-resistant transfer coating, comprising the following steps:

1) Under the protection of dry nitrogen, dehydrate and vacuum 6-14% oligomer polyol at 100-110°C for 1 hour, and cool down to 50-60°C;

2) Add 10-12% diisocyanate, heat up to 85°C±3 from exotherm, react for 2 hours, and cool down to 52-54°C;

3) Mix 12-16% of hydrophilic chain extender, 1.5-3% of cross-linking agent and 2-4% of NMP, add after mixing, pay attention not to raise the temperature too fast, react at 70-75°C for 1 hour ;

4) Add 0.006-0.012% catalyst and react at 60-65°C for 2 hours;

5), while cooling down, add 12-18% acetone to lower the temperature below 30-35°C;

6) Discharge the prepolymer into the dispersion bucket, quickly add the amine chain extender, and disperse at high speed for 1 minute;

7) Quickly add neutralizer and ice pure water within 1 minute, and disperse at high speed for 20 minutes;

8), evacuating at 57-60° C. for 1 hour to remove the solvent to obtain a water-based polyurethane emulsion for heat-resistant transfer coating.

The viscosity of the obtained water-based polyurethane emulsion for the temperature-resistant transfer coating is 14±2 seconds/25°C.

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

1. The water-based polyurethane emulsion of a kind of temperature-resistant transfer coating of the present invention adopts oligomer polyol, diisocyanate, hydrophilic chain extender, crosslinking agent and amine chain extender, and uses the two-step method of prepolymer method To prepare the prepolymer, quickly stir emulsification, vacuumize the solvent, and control the temperature of the reaction, the density of the crosslink, and the degree of chain extension to generate a water-based polyurethane emulsion with a larger molecular weight;

2. A water-based polyurethane emulsion for a temperature-resistant transfer coating of the present invention adopts a suitable hydrophilic chain extender and a suitable ratio to achieve a comprehensive index of water-based polyurethane emulsion with less particle size and good leveling, and adopts a suitable cross-linking agent The appropriate molecular weight can be achieved by using the combination and ratio of the additives, so that the product has good heat resistance, and at the same time, taking into account the characteristics of easy peeling, the prepared water-based polyurethane emulsion for temperature-resistant transfer coatings has excellent performance, and the film can be easily peeled off. The temperature can reach 160 ℃, no yellowing and sticking phenomenon, which is better than similar foreign products;

3. The method for preparing a water-based polyurethane emulsion of a temperature-resistant transfer coating of the present invention has simple synthesis process, easy control of reaction, good repeatability, appropriate particle size of the emulsion, good production quality, good heat resistance, environmentally friendly and safe process synthesis , very little smell,;

4. A method for preparing a water-based polyurethane emulsion for a temperature-resistant transfer coating of the present invention uses a two-step method of the prepolymer method to prepare the prepolymer, which overcomes the large particle size range of the traditional polyurethane emulsion, coarse particle size, and stable storage There are many deficiencies such as poor performance and poor physical properties of the film-forming material.

【Detailed ways】

The present invention will be further described below in conjunction with specific embodiment:

Example 1:

A water-based polyurethane emulsion for heat-resistant transfer coatings, comprising the following components by weight:

The preparation method of the water-based polyurethane emulsion of the temperature-resistant transfer coating of embodiment 1 may further comprise the steps:

1) Under the protection of dry nitrogen, dehydrate and vacuum polycarbonate diol (PCDL) at 110°C for 1 hour, and cool down to 60°C;

2) Add H12MDI, heat up to 88°C from exotherm, react for 2 hours, then cool down to 54°C;

3) Mix dimethylolpropionic acid (DMPA), TMP, CHDM, BEPD cross-linking agent and NMP, then add, the temperature should not rise too fast, react at 75°C for 1 hour;

4) Add the catalyst and react at 65°C for 2 hours;

5), while cooling down, add acetone and cool down to 35°C;

6) Discharge the prepolymer into the dispersion bucket, quickly add DMEA, and disperse at high speed for 1 minute;

7) Quickly add triethylamine and ice pure water within 1 minute, and disperse at high speed for 20 minutes;

8), evacuating at 60° C. for 1 hour to remove the solvent to obtain a water-based polyurethane emulsion for heat-resistant transfer coating.

Example 2:

A water-based polyurethane emulsion for heat-resistant transfer coatings, comprising the following components by weight:

The preparation method of the water-based polyurethane emulsion of the temperature-resistant transfer coating of embodiment 2 may further comprise the steps:

1) Under the protection of dry nitrogen, dehydrate polycarbonate diol (PCDL) at 105°C for 1 hour and then cool it down to 55°C;

2) Add H12MDI, heat up to 86°C from exotherm, react for 2 hours, then cool down to 53°C;

3) Mix dimethylolpropionic acid (DMPA), TMP, CHDM, BEPD cross-linking agent and NMP, then add, the temperature should not rise too fast, react at 72°C for 1 hour;

4), add the catalyst, react at 63°C for 2 hours,

5), while cooling down, add acetone and cool down to 33°C;

6) Discharge the prepolymer into the dispersion barrel, quickly add DMEA aqueous solution, and disperse at high speed for 1 minute;

7) Quickly add triethylamine and ice pure water within 1 minute, and disperse at high speed for 20 minutes;

8), evacuate at 58°C for 1 hour to remove the solvent, and obtain a water-based polyurethane emulsion for heat-resistant transfer coating.

Embodiment 3:

A water-based polyurethane emulsion for heat-resistant transfer coatings, comprising the following components by weight:

The preparation method of the water-based polyurethane emulsion of the temperature-resistant transfer coating of embodiment 3 may further comprise the steps:

1) Under the protection of dry nitrogen, dehydrate and vacuum neopentyl glycol adipate (PNA) at 108°C for 1 hour, and cool down to 55°C;

2) Add H12MDI, heat up to 85°C from exotherm, react for 2 hours, then cool down to 52°C;

3) Mix dimethylolpropionic acid (DMPA), TMP, CHDM, BEPD cross-linking agent and NMP, then add, the temperature should not rise too fast, react at 72°C for 1 hour;

4) Add the catalyst and react at 62°C for 2 hours;

5), while cooling down, add acetone and cool down to 32°C;

6) Discharge the prepolymer into the dispersion barrel, quickly add DMEA aqueous solution, and disperse at high speed for 1 minute;

7) Quickly add triethylamine and ice pure water within 1 minute, and disperse at high speed for 20 minutes;

8), evacuate at 58°C for 1 hour to remove the solvent, and obtain a water-based polyurethane emulsion for heat-resistant transfer coating.

Embodiment 4:

A water-based polyurethane emulsion for heat-resistant transfer coatings, comprising the following components by weight:

The preparation method of the water-based polyurethane emulsion of the temperature-resistant transfer coating of embodiment 4 may further comprise the steps:

1) Under the protection of dry nitrogen, dehydrate and vacuum neopentyl glycol adipate (PNA) at 103°C for 1 hour, and cool down to 52°C;

2) Add IPDI, heat up to 84°C from exotherm, react for 2 hours, then cool down to 53°C;

3) Mix dimethylolpropionic acid (DMPA), cross-linking agent of TMP1, CHDM and BEPD and NMP before adding, the temperature should not rise too fast, react at 71°C for 1 hour;

4), then add the catalyst and react at 62°C for 2 hours;

5), while cooling down, add acetone and cool down to 31°C;

6) The prepolymer is discharged into the dispersion bucket, and the DMEA aqueous solution is quickly added, and the dispersion is performed at a high speed for 1 minute;

7) Quickly add triethylamine and ice pure water within 1 minute, and disperse at high speed for 20 minutes.

8), evacuate at 59° C. for 1 hour to remove the solvent, and obtain a water-based polyurethane emulsion for heat-resistant transfer coating.

Embodiment 5:

A water-based polyurethane emulsion for heat-resistant transfer coatings, comprising the following components by weight:

The preparation method of the water-based polyurethane emulsion of the temperature-resistant transfer coating of embodiment 5 may further comprise the steps:

1) Under the protection of dry nitrogen, dehydrate polytetrahydrofuran ether glycol (PTMG) at 100°C for 1 hour and then cool it down to 50°C;

2) Add H12MDI, heat up to 83°C from exotherm, react for 2 hours, then cool down to 52°C;

3) Mix dimethylolbutyric acid with TMP, CHDM, BEPD cross-linking agent and NMP, then add, pay attention not to raise the temperature too fast, react at 70°C for 1 hour;

4) Add the catalyst and react at 60°C for 2 hours;

5), while cooling down, add acetone and cool down to 30°C;

6) Discharge the prepolymer into the dispersing barrel, quickly add the DMEA aqueous solution, and disperse at high speed for 1 minute;

7) Quickly add hexamethylene diamine and ice pure water within 1 minute, and disperse at high speed for 20 minutes;

8), evacuate at 57° C. for 1 hour to remove the solvent, and obtain a water-based polyurethane emulsion for heat-resistant transfer coating.

The performance test of the temperature-resistant transfer coating of Examples 1 to 5 after the water-based polyurethane emulsion is solidified into a film is shown in Table 1:

1. The production process of water-based heat-resistant transfer coating: Take 70 parts of water-based polyurethane emulsion for heat-resistant transfer coating respectively, add them to a glass cup with a volume of 150ml, and then add 27 parts of distilled water, 1 part of film-forming aid, and 1 part 0.6 parts of wetting agent, 0.2 parts of water-based leveling agent (polyether modified silicone), 0.2 parts of water-based defoamer, stirring at 350-550 rpm for 15-30 minutes , until the system is uniform, filter with a 250-mesh filter, and pour the filtrate into a black plastic tank for use.

2. Curing film forming process: Use 2# scraper bar to scrape and coat the water-based heat-resistant transfer coating on the front of the PET film respectively, numbered 1, 2, 3, 4, 5, set the oven temperature to 105°C, and the humidity 10%, place 1, 2, 3, 4, 5 films respectively for 3 hours, and solidify to form a film.

Table 1:

From the above test results, it can be seen that:

1) The water-based polyurethane emulsion of the heat-resistant transfer coating of the present invention has good leveling property, easy peeling, and high temperature resistance.

2) The water-based polyurethane emulsion of the heat-resistant transfer coating of the present invention is a water-dispersed system, has no adverse effects on the human body and the environment, and meets the requirements of national and industrial environmental protection standards.

Claims (9)

1. A water-based polyurethane emulsion for heat-resistant transfer coatings, characterized in that it comprises the composition of matter of the following weight components: Described ice pure water is the water of 0～4 ℃; Described linking agent is three kinds of mixtures of trimethylol propane (TMP), CHDM, BEPD, and the percentage by weight of described trimethylol propane (TMP), CHDM, BEPD in whole emulsion is 1%/0.80% /0.20%, or 2.0%/0.80%/0.20%, or 0.5%/0.5%/0.5%, or 1%/0.5%/1.0%, or 1%/0.8%/0.8%. 2. a kind of temperature-resistant transfer coating water-based polyurethane emulsion according to claim 1, is characterized in that: described oligomer polyol is polycarbonate diol (PCDL), neopentyl glycol adipate diol (PNA), any one of polytetrahydrofuran ether glycol (PTMG). 3. The water-based polyurethane emulsion for heat-resistant transfer coating according to claim 1, characterized in that: the diisocyanate is any one of H12MDI and IPDI. 4. a kind of temperature-resistant transfer coating water-based polyurethane emulsion according to claim 1, is characterized in that: described hydrophilic chain extender is any one in dimethylol propionic acid (DMPA) and dihydroxybutyric acid kind. 5. The water-based polyurethane emulsion of a kind of temperature-resistant transfer coating according to claim 1, characterized in that: the catalyst is stannous octoate. 6. The water-based polyurethane emulsion for a temperature-resistant transfer coating according to claim 1, wherein the amine chain extender is a solution obtained by dissolving DMEA in 3% ice pure water. 7. The water-based polyurethane emulsion for a temperature-resistant transfer coating according to claim 1, characterized in that: the neutralizer is triethylamine. 8. A preparation method of water-based polyurethane emulsion for temperature-resistant transfer coating, characterized in that it may further comprise the steps: 1) Under the protection of dry nitrogen, dehydrate and vacuum 6-14% oligomer polyol at 100-110°C for 1 hour, and cool down to 50-60°C; 2) Add 10-12% diisocyanate, heat up to 85°C±3 from exotherm, react for 2 hours, and cool down to 52-54°C; 3) Mix 12-16% of hydrophilic chain extender, 1.5-3% of cross-linking agent and 2-4% of NMP, add after mixing, pay attention not to raise the temperature too fast, react at 70-75°C for 1 hour ; 4) Add 0.006-0.012% catalyst and react at 60-65°C for 2 hours; 5), while cooling down, add 12-18% acetone to lower the temperature below 30-35°C; 6) Discharge the prepolymer into the dispersion bucket, quickly add the amine chain extender, and disperse at high speed for 1 minute; 7) Quickly add neutralizer and ice pure water within 1 minute, and disperse at high speed for 20 minutes; 8), evacuating at 57-60° C. for 1 hour to remove the solvent to obtain a water-based polyurethane emulsion for heat-resistant transfer coating. 9. The preparation method of a water-based polyurethane emulsion for temperature-resistant transfer coating according to claim 8, characterized in that: the obtained water-based polyurethane emulsion for temperature-resistant transfer coating has a viscosity of 14±2 seconds/25°C.