Bi-component high-wear-resistance waterborne polyurethane coating for paper package surface protection and preparation method thereof

Abstract

The invention relates to the technical field of waterborne polyurethane coatings, and discloses a two-component high-wear-resistance waterborne polyurethane coating for paper package surface protection and a preparation method thereof. The water-based paint comprises the following components in percentage by adding: 20% of water-based matte polyurethane, 30% of a water-based acrylic polymer, 45% of water-based bright polyurethane, 0.5% of dimethylethanolamine, 0.3% of a water-based organic silicon defoaming agent, 1.5% of pasty ultra-high molecular weight polydimethylsiloxane dispersion liquid, 0.2% of a water-based organic silicon flatting agent, 2% of dipropylene glycol butyl ether, 0.2% of an organic tin drier and 0.2% of a Digao TEGO WET 270 base material wetting agent. And 0.4% of a polyether polyurethane associated rheological additive with 25% of active parts. The problems that a traditional paper package surface protection technology is long in degradation period, poor in environmental protection property and low in quality are effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waterborne polyurethane coatings, in particular to a two-component high-wear-resistance waterborne polyurethane coating for paper packaging surface protection and a preparation method thereof. BACKGROUND

[0002] Waterborne polyurethane is a new type of polyurethane system using water as the dispersion medium instead of organic solvents, also known as water-dispersed polyurethane, water-based polyurethane or water-based polyurethane. Waterborne polyurethane uses water as the solvent, has no pollution, is safe and reliable, has excellent mechanical properties, good compatibility, easy modification and other advantages, and is widely used in paper packaging surface protection.

[0003] The existing paper packaging surface is generally coated with plastic film using BOPP coating process, or protected with solvent-based gloss oil or water-based plastic oil. The coating method using plastic film increases the degradation period, the method using solvent-based gloss oil increases VOC emission, and the method using water-based plastic oil increases the drying time, reduces the wear resistance, folding resistance and alcohol cleaning resistance. Therefore, we provide a two-component high-wear-resistance waterborne polyurethane coating for paper packaging surface protection and a preparation method thereof. SUMMARY

[0004] To solve the problems of long degradation period, poor environmental protection and low quality of the traditional paper packaging surface protection process in the background art, the present application provides a two-component high-wear-resistance waterborne polyurethane coating for paper packaging surface protection and a preparation method thereof.

[0005] The present application adopts the following technical solution: a two-component high-wear-resistance waterborne polyurethane coating for paper packaging surface protection, which comprises the following components in the proportion of addition:

[0006] Waterborne matte polyurethane 20%, waterborne acrylic polymer 30%, waterborne glossy polyurethane 45%, dimethyl ethanolamine 0.5%, waterborne silicone defoaming agent 0.3%, paste-like ultra-high molecular weight polydimethylsiloxane dispersion 1.5%, waterborne silicone leveling agent 0.2%, dipropylene glycol butyl ether 2%, organic tin catalyst 0.2%, DiGao TEGO WET 270 substrate wetting agent 0.2%, 25% active polyether polyurethane associated rheological additive 0.4%.

[0007] The preparation method of the two-component high-wear-resistance waterborne polyurethane coating for paper packaging surface protection comprises the following steps:

[0008] The water-based matte polyurethane, water-based acrylic polymer and water-based glossy polyurethane are added into a container and stirred and dispersed for 30-40 min, then dimethyl ethanolamine, water-based silicone defoaming agent, paste-like ultra-high molecular weight polydimethylsiloxane dispersion, water-based silicone leveling agent, dipropylene glycol butyl ether, organic tin catalyst, Di Gu TEGO WET 270 substrate wetting agent and 25% active polyether polyurethane associated rheological additive are added, stirring and dispersing for 30-40 min, and then adding water-based aliphatic polyisocyanate curing agent after the finished product is prepared and stirring and dispersing for 20-30 min to make it uniformly mixed.

[0009] As a further improvement of the above scheme, the preparation method of the water-based matte polyurethane is:

[0010] S1, adding oligomer polyol and diisocyanate to the water-based polyurethane dispersion as the base material, stirring and dispersing, heating to 50-60℃, and reacting for 2.3-3h, obtaining a prepolymer after the reaction is completed;

[0011] S2, adding a chain extender, heating to 40-50℃ and stirring for 0.5-1h, then heating to 60-65℃ and keeping for 1-1.5h, obtaining a high molecular weight polyurethane after the reaction is completed;

[0012] S3, adding water-based fumed silica matt filler to the above polyurethane dispersion and stirring and dispersing, forming a matte effect after 8h of surface drying.

[0013] As a further improvement of the above scheme, the preparation method of the water-based acrylic polymer is:

[0014] S1, adding water and emulsifier to a container, adding initiator after heating to 80℃, controlling the temperature at 85℃±2℃, and adding mixed monomers dropwise, keeping for 1h after the dropwise addition is completed;

[0015] S2, cooling to 75℃, adding tackifier and crosslinking agent and continuing to stir for 1h to complete polymerization.

[0016] As a further improvement of the above scheme, the mixed monomers include acrylic acid, butyl acrylate, styrene and vinyl acetate, and the mixed monomers need to be added dropwise within 2h.

[0017] As a further improvement of the above scheme, the preparation method of the water-based glossy polyurethane is:

[0018] S1, adding oligomer polyol and diisocyanate to a flask in proportion, heating to 80℃ and reacting for 2h;

[0019] S2, adding a chain extender and a hydrophilic group chain extender after cooling, continuing to react for 2h until the NCO content meets the standard;

[0020] S3, adding acetone to adjust viscosity, and adding neutralizing agent to neutralize carboxyl group;

[0021] S4, adding deionized water under high speed stirring to form emulsion;

[0022] S5, adding post chain extender to perform secondary chain extension to enhance gloss.

[0023] As a further improvement of the above scheme, the molecular weight of the oligomer polyol is generally about 2000.

[0024] As a further improvement of the above scheme, the ratio of the oligomer polyol to diisocyanate is 1:1.

[0025] As a further improvement of the above scheme, the adding ratio of the water-based aliphatic polyisocyanate curing agent is 2%.

[0026] As a further improvement of the above scheme, the prepolymer needs to have a molecular weight of 800-14000 Dalton / mol, a branching degree of 0-3.0 mol / kg, and an isocyanate functionality of 2.0-6.0.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] The present application replaces the traditional paper packaging surface protection process, not only has the advantages of degradability, environmental protection, and reduction of natural garbage, but also can ensure the protection effect on the surface of paper packaging, and has strong practicability. DETAILED DESCRIPTION

[0029] In the following, the present application will be further described in conjunction with specific embodiments. It should be noted that the embodiments described below or the technical features thereof can be combined with each other to form new embodiments without conflict.

[0030] Embodiment 1:

[0031] The two-component high-wear-resistance water-based polyurethane coating for paper packaging surface protection of the present embodiment includes the following components in the adding ratio:

[0032] Water-based matte polyurethane 20%, water-based acrylic polymer 30%, water-based bright polyurethane 45%, dimethyl ethanolamine 0.5%, water-based silicone defoaming agent 0.3%, paste-like ultra-high molecular weight polydimethylsiloxane dispersion 1.5%, water-based silicone leveling agent 0.2%, dipropylene glycol butyl ether 2%, organic tin catalyst 0.2%, DiGao TEGO WET 270 substrate wetting agent 0.2%, 25% active polyether polyurethane associated rheological additive 0.4%.

[0033] The preparation method of the paper packaging surface protection two-component high-wear-resistant water-based polyurethane coating comprises the following steps:

[0034] The water-based matte polyurethane, the water-based acrylic polymer, and the water-based glossy polyurethane are added to a container and stirred and dispersed for 30-40 min, then dimethyl ethanolamine, a water-based silicone defoaming agent, a paste-like ultra-high molecular weight polydimethylsiloxane dispersion, a water-based silicone leveling agent, dipropylene glycol butyl ether, an organic tin drier, Di Gu TEGO WET 270 substrate wetting agent, and 25% active polyether polyurethane associated rheological auxiliary agent are added, and stirring and dispersion are continued for 30-40 min, and then the water-based aliphatic polyisocyanate curing agent is added to the finished product and stirring and dispersion are continued for 20-30 min to uniformly mix.

[0035] The water-based aliphatic polyisocyanate curing agent is added in a proportion of 2%.

[0036] The preparation method of the water-based matte polyurethane is as follows:

[0037] First step, the oligomer polyol and diisocyanate are added to the water-based polyurethane dispersion as a base material, stirring and dispersion, the temperature is increased to 50-60℃, the reaction time is 2.3-3h, and the prepolymer is obtained after the reaction is completed;

[0038] Second step, the chain extender is added, the temperature is increased to 40-50℃ and stirring is performed for 0.5-1h, then heating is performed to 60-65℃ and the temperature is kept for 1-1.5h, and the high molecular weight polyurethane is obtained after the reaction is completed;

[0039] Third step, the water-based matting filler of fumed silica is added to the polyurethane dispersion and stirring and dispersion are performed, and the matte effect is formed after 8h of surface drying.

[0040] The preparation method of the water-based acrylic polymer is as follows:

[0041] First step, the water and emulsifier are added to a container, the temperature is increased to 80℃ after heating, the initiator is added, the temperature is controlled at 85℃±2℃, and the mixed monomers are added dropwise, and the temperature is kept for 1h after the dropwise addition is completed;

[0042] Second step, the temperature is decreased to 75℃, the tackifier and crosslinking agent are added, and stirring is continued for 1h to complete the polymerization.

[0043] The mixed monomers include acrylic acid, butyl acrylate, styrene, and vinyl acetate, and the mixed monomers need to be added dropwise within 2h.

[0044] The preparation method of the water-based glossy polyurethane is as follows:

[0045] First step, the oligomer polyol and diisocyanate are added to a flask in a proportion, and heating is performed to 80℃ for 2h;

[0046] The second step, after cooling, chain extender and hydrophilic group chain extender are added, and the reaction is continued for 2h until the NCO content reaches the standard;

[0047] The third step, acetone is added to adjust the viscosity, and a neutralizing agent is added to neutralize the carboxyl group.

[0048] The fourth step, under high-speed stirring, deionized water is added to form an emulsion.

[0049] The fifth step, a post-chain extender is added for secondary chain extension to enhance gloss.

[0050] The molecular weight of the oligomer polyol is generally around 2000, and the ratio of the oligomer polyol to diisocyanate is 1:1.

[0051] Example 2:

[0052] This example is based on example 1, and the further improvement is that the prepolymer has a molecular weight of 800-14000 daltons / mol, a branching degree of 0-3.0 mol / kg, and an isocyanate functionality of 2.0-6.0.

[0053] The components of the present application are all general standard components or components known to those skilled in the art, and their structures and principles can be known by technical personnel through technical manuals or through conventional experimental methods. It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any mark in the claims should not be considered as limiting the claims involved.

[0054] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A two-component high abrasion resistant waterborne polyurethane coating for paper packaging surface protection, characterized by, The following components are included in the proportion of addition: Waterborne matte polyurethane 20%, waterborne acrylic polymer 30%, waterborne glossy polyurethane 45%, dimethyl ethanolamine 0.5%, waterborne silicone defoaming agent 0.3%, paste-like ultra-high molecular weight polydimethylsiloxane dispersion 1.5%, waterborne silicone leveling agent 0.2%, dipropylene glycol butyl ether 2%, organic tin catalyst 0.2%, di-guo TEGO WET 270 substrate wetting agent 0.2%, 25% active polyether polyurethane associative rheological agent 0.4%; The preparation method of the two-component high-wear-resistant waterborne polyurethane coating for paper packaging surface protection comprises the following steps: The waterborne matte polyurethane, waterborne acrylic polymer and waterborne glossy polyurethane are added to a container and stirred and dispersed for 30-40 min, then dimethyl ethanolamine, waterborne silicone defoaming agent, paste-like ultra-high molecular weight polydimethylsiloxane dispersion, waterborne silicone leveling agent, dipropylene glycol butyl ether, organic tin catalyst, di-guo TEGO WET 270 substrate wetting agent and 25% active polyether polyurethane associative rheological agent are added, stirring and dispersion is continued for 30-40 min, after the finished product is prepared, waterborne aliphatic polyisocyanate curing agent is added and stirring and dispersion is continued for 20-30 min to uniformly mix.

2. A two-component high abrasion resistant waterborne polyurethane coating for paper packaging surface protection according to claim 1, characterized in that, The preparation method of the waterborne matte polyurethane is: S1, waterborne polyurethane dispersion is used as a base material, oligomeric polyol and diisocyanate are added, stirring and dispersion is performed, the temperature is raised to 50-60℃, the reaction time is 2.3-3h, after the reaction is completed, a prepolymer is obtained; S2, a chain extender is added, the temperature is raised to 40-50℃ and stirring is performed for 0.5-1h, then heating is performed to 60-65℃ and the temperature is kept for 1-1.5h, after the reaction is completed, a high molecular weight polyurethane is obtained; S3, fumed silica waterborne matting filler is added to the polyurethane dispersion and stirring and dispersion is performed, after 8h of surface drying, a matte effect is formed.

3. A two component high abrasion resistant waterborne polyurethane coating for paper packaging surface protection according to claim 2, characterized in that, The preparation method of the waterborne acrylic polymer is: S1, water and emulsifier are added to a container, after heating to 80℃, an initiator is added, the temperature is controlled at 85℃±2℃, mixed monomers are added dropwise, after the dropwise addition is completed, the temperature is kept for 1h; S2, after the temperature is lowered to 75℃, tackifier and crosslinking agent are added and stirring is continued for 1h to complete the polymerization.

4. A two component high abrasion resistant waterborne polyurethane coating for paper packaging surface protection according to claim 3, characterized in that, The mixed monomers include acrylic acid, butyl acrylate, styrene and vinyl acetate, and the mixed monomers need to be added dropwise within 2h.

5. A two component high abrasion resistant waterborne polyurethane coating for paper packaging surface protection according to claim 4, characterized in that, The preparation method of the waterborne glossy polyurethane is: S1, oligomeric polyol and diisocyanate are added to a flask in a proportion, heating is performed to 80℃ and the reaction is performed for 2h; S2, after the temperature is lowered, a chain extender and a hydrophilic group chain extender are added, the reaction is continued for 2h until the NCO content meets the standard; S3, acetone is added to adjust the viscosity, a neutralizing agent is added to neutralize the carboxyl group; S4, deionized water is added under high-speed stirring to form an emulsion; S5, a post-chain extender is added for secondary chain extension to enhance the gloss.

6. A two component high abrasion resistant waterborne polyurethane coating for paper packaging surface protection according to claim 5, characterized in that, The molecular weight of the oligomeric polyol is generally about 2000.

7. A two component high abrasion resistant waterborne polyurethane coating for paper packaging surface protection according to claim 6, characterized in that, The proportion of the oligomeric polyol and diisocyanate is 1:

1.

8. A two component high abrasion resistant waterborne polyurethane coating for paper packaging surface protection according to claim 9, characterized in that, The addition proportion of the waterborne aliphatic polyisocyanate curing agent is 2%.

9. A two component high abrasion resistant waterborne polyurethane coating for paper packaging surface protection according to claim 8, characterized in that, The prepolymer has a molecular weight of 800 to 14,000 Dalton / mole, a branching degree of 0 to 3.0 mol / kg, and an isocyanate functionality of 2.0 to 6.0.