Polyurethane ink resin as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of polyurethane resin, and particularly relates to polyurethane printing ink resin as well as a preparation method and application thereof, and the polyurethane printing ink resin comprises the following components in percentage by weight: 10-20wt% of polyether polyol, 10-20wt% of polyether polyol, 10-20wt% of polyether polyol, 10-20wt% of polyether polyol 5 to 15 wt% of hydroxyl-terminated hydrogenated polybutadiene; 5 to 15 weight percent of isocyanate; 1 to 5 wt% of polyethyleneimine; 0.5 wt% to 3 wt% of an end-capping reagent; 0.01 wt% to 0.5 wt% of a catalyst; and 50-70 wt% of an organic solvent. The adhesive force of the obtained polyurethane ink resin on BOPP and PE is improved, and meanwhile, pigment particles can be better wrapped, so that the anti-precipitation performance of ink is improved.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane resin technology, and particularly relates to a polyurethane ink resin, its preparation method, and its application. Background Technology

[0002] In the current flexible packaging printing field, there are various types of composite inks, such as polyamide inks, nitrocellulose inks, and chlorinated polypropylene inks. Polyurethane inks, due to their excellent substrate adhesion, printability, and greater safety and environmental friendliness, have gradually replaced other ink systems in recent years and become the mainstream in the market.

[0003] Polyurethane resin is a high-molecular polymer composed of polyols and isocyanates. Its flexibility can be improved by adjusting the ratio of hard and soft segments. Polyurethane resin has good flexibility, substrate adhesion, low odor, and good temperature resistance, and is compatible with a variety of resins such as nitrocellulose, vinyl chloride resin, and polyketone resin. As the requirements for polyurethane-based inks become increasingly stringent, the development of high-performance polyurethane ink resins is also making continuous progress.

[0004] For example, Chinese patent document CN106554476A discloses a polyurethane resin for gravure printing inks on flexible packaging and its preparation method. This ink resin can improve the pigment dispersibility, transparency, and drying speed of the ink. Chinese patent document CN 113122122A discloses a high-solids polyurethane ink resin and its preparation method. By introducing special functional amine chain extenders and end-capping agents, a high-solids ink resin is obtained, which can be used to prepare more environmentally friendly high-solids, low-viscosity inks. US patent document US20080226880A1 discloses a solvent-based high-performance polyurethane resin. By adjusting the molecular weight distribution of polyurethane, an ink resin with good resolubility and printability is obtained. This resin can be used to prepare high-speed printing inks.

[0005] However, current polyurethane-based ink resins still have some shortcomings in practical applications. For example, while polyurethane resins exhibit good adhesion to plastic substrates such as PET and NY, their adhesion to non-polar substrates such as BOPP and PE is poor, requiring the addition of adhesion promoters, curing agents, and other additives to meet customer requirements. This undoubtedly increases ink costs and operational complexity. Furthermore, conventional polyurethane resins do not provide ideal wetting and dispersibility for some pigments, leading to sedimentation problems during storage and affecting the ink's usability. Summary of the Invention

[0006] The purpose of this invention is to address some existing problems with polyurethane inks by providing a polyurethane ink resin, its preparation method, and its application. The polyurethane ink resin obtained by this invention has improved adhesion to BOPP and PE, and can also better encapsulate pigment particles, thereby improving the ink's anti-settling properties.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] In a first aspect, a high-performance polyurethane ink resin is provided, comprising the following components in weight percentages (e.g., based on a total weight of 100 wt%):

[0009] Polyether polyols, 10–20 wt% (e.g., 12 wt%, 14 wt%, 15 wt%, 16 wt%, 18 wt%);

[0010] Hydroxyl-terminated hydrogenated polybutadiene, 5–15 wt% (e.g., 6 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%);

[0011] Isocyanates, 5–15 wt% (e.g., 6 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%);

[0012] Polyethyleneimine, 1–5 wt% (e.g., 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%);

[0013] End-capping agent, 0.5wt% to 3wt% (e.g., 0.6wt%, 0.8wt%, 1.0wt%, 1.5wt%, 2.0wt%, 2.5wt%);

[0014] Catalyst, 0.01wt% to 0.5wt% (e.g., 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.1wt%, 0.2wt%, 0.25wt%, 0.3wt%, 0.4wt%, 0.45wt%);

[0015] Organic solvent, 50–70 wt% (e.g., 55 wt%, 60 wt%, 65 wt%, 68 wt%).

[0016] In some embodiments of the polyurethane ink resin provided by the present invention, the polyether polyol is polyoxypropylene glycol.

[0017] In some embodiments, the number average molecular weight of the polyoxypropylene glycol is 1,000 to 4,000 (e.g., 1,200, 1,500, 1,800, 2,000, 2,500, 3,000, 3,500).

[0018] In some embodiments, the number average molecular weight of the hydroxyl-terminated hydrogenated polybutadiene is 1,000 to 4,000 (e.g., 1,200, 1,500, 1,800, 2,000, 2,500, 3,000, 3,500).

[0019] In this invention, for example, the hydroxyl-terminated hydrogenated polybutadiene can be GI-2000 from Nippon Soda Corporation or Krasol HLBH-P 2000 from Cray Valley Corporation of the United States.

[0020] In some embodiments, the isocyanate is selected from one or more of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, isoflurone diisocyanate, and hexamethylene diisocyanate.

[0021] In some embodiments, the number-average molecular weight of the polyethyleneimine is 1000 to 2000.

[0022] In some embodiments, the capping agent is a small molecule monoamine with a molecular weight of, for example, 20-400; for example, it may be selected from one or more of ethanolamine, diethanolamine, n-butylamine and di-n-butylamine.

[0023] In some embodiments, the catalyst is selected from one or more of stannous octoate, dibutyltin dilaurate, and bismuth decanoate.

[0024] In some embodiments, the organic solvent is selected from one or more of ethyl acetate, n-propyl acetate, n-butyl acetate, ethanol, and isopropanol. For example, the organic solvent may be a mixture of ethyl acetate, n-propyl acetate, n-butyl acetate, and ethanol or isopropanol.

[0025] In a second aspect, a method for preparing the polyurethane ink resin as described above is provided, comprising the following steps:

[0026] (a) Mix polyether polyol and hydrogenated polybutadiene with hydroxyl groups evenly, then add isocyanate and catalyst to it and heat to 70-100°C (e.g., 75°C, 80°C, 85°C, 90°C, 95°C) to react and obtain the first reactant containing NCO groups.

[0027] (b) Add a capping agent to the first reactant and react to obtain a second reactant containing NCO groups;

[0028] (c) Mix polyethyleneimine with an organic solvent (for example, by stirring for 0.5 h, 1.0 h, 1.5 h, or 2 h) to obtain a homogeneous mixture; then add the second reactant to the homogeneous mixture and react at room temperature to obtain a polyurethane ink resin.

[0029] According to the preparation method provided by the present invention, in some embodiments, the reaction time after heating to 70-100°C in step (a) is 1-3 h (e.g., 1.5 h, 2.0 h, 2.5 h); the NCO content in the obtained first reactant is 1.2 wt%-3.0 wt% (e.g., 1.5 wt%, 1.8 wt%, 2.0 wt%, 2.2 wt%, 2.5 wt%, 2.8 wt%).

[0030] In some embodiments, the reaction time after adding the capping agent in step (b) is 0.5 to 2 hours (e.g., 1.0 hours, 1.5 hours), and the NCO content in the resulting second reactant is 0.5 wt% to 2.0 wt% (e.g., 0.6 wt%, 0.8 wt%, 1.0 wt%, 1.5 wt%, 1.8 wt%).

[0031] In some implementations, the reaction time for step (c) at room temperature is 0.5 to 2 hours (e.g., 1.0 hour, 1.5 hours).

[0032] In a third aspect, the application of the polyurethane ink resin as described above or the polyurethane ink resin prepared by the preparation method as described above in the field of flexible packaging printing inks is provided.

[0033] In this article, the application steps or operating processes of polyurethane ink resin in the field of flexible packaging printing ink can be conventional methods in this field, and will not be elaborated here.

[0034] Compared with the prior art, the beneficial effects of the technical solution of the present invention are at least as follows:

[0035] (1) The high-performance polyurethane ink resin provided by the present invention has a low polarity end-hydroxyl hydrogenated polybutadiene structure introduced into its molecular structure, which can improve its bonding force with non-polar substrates, thereby improving the adhesion of the resin to BOPP and PE.

[0036] (2) In the high-performance polyurethane ink resin provided by the present invention, polyethyleneimine is used as a chain extender to extend the chain, thereby introducing a large number of -NH- polar groups at the molecular end. These polar groups can increase the wettability of the resin to organic pigments and can better encapsulate pigment particles, thereby improving the anti-settling performance of the prepared ink. Detailed Implementation

[0037] To provide a detailed understanding of the technical features and content of this invention, preferred embodiments will be described in more detail below. While preferred embodiments are described in the examples, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply.

[0038] In the following examples and comparative examples, the sources of some reagents or raw materials used, unless otherwise specified, are all conventional products that can be purchased commercially.

[0039] Example 1

[0040] High-performance polyurethane ink resin, comprising the following components by weight percentage (based on a total weight of 100 wt%):

[0041] Polyether polyol, 20 wt%;

[0042] Hydroxyl-terminated hydrogenated polybutadiene, 5 wt%;

[0043] Isocyanate, 5 wt%;

[0044] Polyethyleneimine, 2 wt%;

[0045] End-capping agent, 1 wt%;

[0046] Catalyst, 0.01 wt%;

[0047] Organic solvent, 66.99 wt%; of which,

[0048] The polyether polyol is Wanhua Chemical's C2020, with a number-average molecular weight of 2000.

[0049] Hydroxyl-terminated hydrogenated polybutadiene is GI-2000 from Nippon Soda Co., Ltd., with a number-average molecular weight of 2000.

[0050] The isocyanate is Wanhua Chemical's 4,4'-diphenylmethane diisocyanate (MDI-100);

[0051] The polyethyleneimine used is SP-012 from Nippon Shokubai, with a number-average molecular weight of 1200.

[0052] The capping agent is di-n-butylamine;

[0053] The catalyst is stannous octoate;

[0054] The organic solvent is a mixture of ethyl acetate and isopropanol, with a mass ratio of ethyl acetate to isopropanol of 3:1.

[0055] The preparation method of high-performance polyurethane ink resin is as follows:

[0056] (a) First, add 20 kg of polyether polyol C2020 and 5 kg of hydroxyl-terminated hydrogenated polybutadiene GI-2000 to container A in sequence, turn on the stirrer to mix the materials evenly, then add 5 kg of MDI-100 and 0.01 kg of stannous octoate catalyst to it, mix evenly and heat to 70°C to react for 3 h to obtain the first reactant with NCO% = 2.1 wt%.

[0057] (b) Add 1 kg of the capping agent di-n-butylamine to the obtained first reactant, and after reacting for 0.5 h, a second reactant with NCO% = 0.98 wt% is obtained;

[0058] (c) Add 2 kg of polyethyleneimine SP-012, 50.24 kg of ethyl acetate and 16.75 kg of isopropanol to container B and stir for 0.5 h to mix them evenly; then add the second reactant obtained in container A to container B and react at room temperature for 1 h to obtain the polyurethane ink resin.

[0059] Example 2

[0060] High-performance polyurethane ink resin, comprising the following components by weight percentage (based on a total weight of 100 wt%):

[0061] Polyether polyol, 10 wt%;

[0062] Hydroxyl-terminated hydrogenated polybutadiene, 15 wt%;

[0063] Isocyanate, 6.4 wt%;

[0064] Polyethyleneimine, 1.5 wt%;

[0065] End-capping agent, 1.9 wt%;

[0066] Catalyst, 0.2 wt%;

[0067] Organic solvent, 65 wt%; of which,

[0068] The polyether polyol is Wanhua Chemical's C2010D, with a number-average molecular weight of 1000.

[0069] The hydroxyl-terminated hydrogenated polybutadiene is Krasol HLBH-P 2000 from Cray Valley, with a number average molecular weight of 2000.

[0070] The isocyanate is Wanhua Chemical's isoflurone diisocyanate;

[0071] The polyethyleneimine used is SP-018 from Nippon Shokubai, with a number-average molecular weight of 1800.

[0072] The capping agent is diethanolamine;

[0073] The catalyst is dibutyltin dilaurate;

[0074] The organic solvent is a mixture of n-propyl acetate and ethanol, with a mass ratio of n-propyl acetate to ethanol of 1:1.

[0075] The preparation method of high-performance polyurethane ink resin is as follows:

[0076] (a) First, add 10 kg of polyether polyol C2010D and 15 kg of hydroxyl-terminated hydrogenated polybutadiene HLBH-P 2000 to container A in sequence, turn on the stirrer to mix the materials evenly, then add 6.4 kg of isoflurone diisocyanate and 0.2 kg of dibutyltin dilaurate catalyst to it, mix evenly and heat to 100°C to react for 1 h to obtain the first reactant with NCO% = 3.0 wt%;

[0077] (b) 1.9 kg of the capping agent diethanolamine was added to the first reactant, and after reacting for 1 h, a second reactant with NCO% = 0.57 wt% was obtained.

[0078] (c) Add 1.5 kg of polyethyleneimine SP-018, 32.5 kg of n-propyl acetate and 32.5 kg of ethanol to container B and stir for 1 h to mix them evenly; then add the second reactant obtained in container A to container B and react at room temperature for 1 h to obtain the polyurethane ink resin.

[0079] Example 3

[0080] High-performance polyurethane ink resin, comprising the following components by weight percentage (based on a total weight of 100 wt%):

[0081] Polyether polyol, 16 wt%;

[0082] Hydroxyl-terminated hydrogenated polybutadiene, 10 wt%;

[0083] Isocyanate, 8 wt%;

[0084] Polyethyleneimine, 2 wt%;

[0085] End-capping agent, 2wt%;

[0086] Catalyst, 0.1 wt%;

[0087] Organic solvent, 61.9 wt%; of which,

[0088] The polyether polyol is DL-1000D from Shandong Lanxing Dongda, with a number average molecular weight of 1000.

[0089] The hydroxyl-terminated hydrogenated polybutadiene is Krasol HLBH-P 2000 from Cray Valley, with a number average molecular weight of 2000.

[0090] The isocyanate is Wanhua Chemical's 4,4'-diphenylmethane diisocyanate (MDI-100);

[0091] The polyethyleneimine used is SP-018 from Nippon Shokubai, with a number-average molecular weight of 1800.

[0092] The capping agent is di-n-butylamine;

[0093] The catalyst is bismuth decanoate;

[0094] The organic solvent is a mixture of n-butyl acetate and ethanol, with a mass ratio of n-butyl acetate to ethanol of 30:31.9.

[0095] The preparation method of high-performance polyurethane ink resin is as follows:

[0096] (a) First, add 16 kg of polyether polyol DL-1000D and 10 kg of hydroxyl-terminated hydrogenated polybutadiene HLBH-P 2000 to container A in sequence, turn on the stirrer to mix the materials evenly, then add 8 kg of 4,4'-diphenylmethane diisocyanate and 0.1 kg of bismuth decanoate catalyst to it, mix evenly and heat to 90°C to react for 1 h to obtain the first reactant with NCO% = 2.7 wt%.

[0097] (b) Add 2 kg of the capping agent di-n-butylamine to the obtained first reactant, and after reacting for 1 h, a second reactant with NCO% = 0.75 wt% is obtained;

[0098] (c) Add 2 kg of polyethyleneimine SP-018, 30 kg of butyl acetate and 31.9 kg of ethanol to container B and stir for 1 h to mix them evenly; then add the second reactant obtained in container A to container B and react at room temperature for 0.5 h to obtain the polyurethane ink resin.

[0099] Example 4

[0100] High-performance polyurethane ink resin, comprising the following components by weight percentage (based on a total weight of 100 wt%):

[0101] Polyether polyol, 20 wt%;

[0102] Hydroxyl-terminated hydrogenated polybutadiene, 15 wt%;

[0103] Isocyanate, 6 wt%;

[0104] Polyethyleneimine, 5 wt%;

[0105] End-capping agent, 3 wt%;

[0106] Catalyst, 0.1 wt%;

[0107] Organic solvent, 50.9 wt%; of which,

[0108] The polyether polyol is Wanhua Chemical's C2040D, with a number-average molecular weight of 4000.

[0109] Hydroxyl-terminated hydrogenated polybutadiene is GI-2000 from Nippon Soda Co., Ltd., with a number-average molecular weight of 2000.

[0110] The isocyanate is Wanhua Chemical's isoflurone diisocyanate;

[0111] The polyethyleneimine used is SP-012 from Nippon Shokubai, with a number-average molecular weight of 1200.

[0112] The capping agent is di-n-butylamine;

[0113] The catalyst is dibutyltin dilaurate;

[0114] The organic solvent is ethyl acetate.

[0115] The preparation method of high-performance polyurethane ink resin is as follows:

[0116] (a) First, add 200 kg of polyether polyol C2040D and 150 kg of hydroxyl-terminated hydrogenated polybutadiene GI-2000 to container A in sequence, turn on the stirrer to mix the materials evenly, then add 60 kg of isoflurone diisocyanate and 1 kg of dibutyltin dilaurate catalyst to it, mix evenly and heat to 80°C to react for 3 h to obtain the first reactant with NCO% = 3.0 wt%.

[0117] (b) Add 30 kg of the capping agent di-n-butylamine to the obtained first reactant, and after reacting for 0.5 h, a second reactant with NCO% = 0.55 wt% is obtained;

[0118] (c) Add 50 kg of polyethyleneimine SP-012 and 509 kg of ethyl acetate to container B and stir for 0.5 h to mix them evenly; then add the second reactant obtained in container A to container B and react at room temperature for 1 h to obtain the polyurethane ink resin.

[0119] Example 5

[0120] High-performance polyurethane ink resin, comprising the following components by weight percentage (based on a total weight of 100 wt%):

[0121] Polyether polyol, 18 wt%;

[0122] Hydroxyl-terminated hydrogenated polybutadiene, 12 wt%;

[0123] Isocyanate, 6.2 wt%;

[0124] Polyethyleneimine, 1 wt%;

[0125] End-capping agent, 2.7 wt%;

[0126] Catalyst, 0.1 wt%;

[0127] Organic solvent, 60 wt%; of which,

[0128] The polyether polyol is Wanhua Chemical's C2010D, with a number-average molecular weight of 1000.

[0129] Hydroxyl-terminated hydrogenated polybutadiene is GI-2000 from Nippon Soda Co., Ltd., with a number-average molecular weight of 2000.

[0130] The isocyanate is hexamethylene diisocyanate from Wanhua Chemical.

[0131] The polyethyleneimine used is SP-012 from Nippon Shokubai, with a number-average molecular weight of 1200.

[0132] The capping agent is di-n-butylamine;

[0133] The catalyst is stannous octoate;

[0134] The organic solvent is n-propyl acetate.

[0135] The preparation method of high-performance polyurethane ink resin is as follows:

[0136] (a) First, add 18 kg of polyether polyol C2010D and 12 kg of hydroxyl-terminated hydrogenated polybutadiene GI-2000 to container A in sequence, turn on the stirrer to mix the materials evenly, then add 6.2 kg of hexamethylene diisocyanate and 0.1 kg of stannous octoate catalyst to it, mix evenly and heat to 80°C to react for 3 h to obtain the first reactant with NCO% = 3.0 wt%;

[0137] (b) 2.7 kg of the capping agent di-n-butylamine was added to the obtained first reactant, and after reacting for 0.5 h, a second reactant with NCO% = 0.5 wt% was obtained;

[0138] (c) Add 1 kg of polyethyleneimine SP-012 and 60 kg of n-propyl acetate to container B and stir for 0.5 h to mix them evenly; then add the second reactant obtained in container A to container B and react at room temperature for 1 h to obtain the polyurethane ink resin.

[0139] Comparative Example 1

[0140] The preparation method of the polyurethane ink resin is the same as in Example 1, except that the hydroxyl-terminated hydrogenated polybutadiene GI-2000 in the formulation is replaced with a conventional polyether polyol; that is, the polyurethane ink resin contains the following components in weight percentage (based on a total weight of 100 wt%):

[0141] Polyether polyol, 25 wt%;

[0142] Isocyanate, 5 wt%;

[0143] Polyethyleneimine, 2 wt%;

[0144] End-capping agent, 1 wt%;

[0145] Catalyst, 0.01 wt%;

[0146] Organic solvent, 66.99 wt%; of which,

[0147] The polyether polyol is Wanhua Chemical's C2020, with a number-average molecular weight of 2000.

[0148] The isocyanate is Wanhua Chemical's 4,4'-diphenylmethane diisocyanate (MDI-100);

[0149] The polyethyleneimine used is SP-012 from Nippon Shokubai, with a number-average molecular weight of 1200.

[0150] The capping agent is di-n-butylamine;

[0151] The catalyst is stannous octoate;

[0152] The organic solvent is a mixture of ethyl acetate and isopropanol, with a mass ratio of ethyl acetate to isopropanol of 3:1.

[0153] The preparation method of polyurethane ink resin is as follows:

[0154] (a) First, add 25 kg of polyether polyol C2020 to container A, start stirring, then add 5 kg of MDI-100 and 0.01 kg of stannous octoate catalyst and heat to 70 °C for 3 h to obtain the first reactant with NCO% = 2.1 wt%.

[0155] (b) Add 1 kg of the capping agent di-n-butylamine to the obtained first reactant, and after reacting for 0.5 h, a second reactant with NCO% = 0.98 wt% is obtained;

[0156] (c) Add 2 kg of polyethyleneimine SP-012, 50.24 kg of ethyl acetate and 16.75 kg of isopropanol to container B and stir for 0.5 h to mix them evenly; then add the second reactant obtained in container A to container B and react at room temperature for 1 h to obtain the polyurethane ink resin.

[0157] Comparative Example 2

[0158] The preparation method of the polyurethane ink resin is the same as in Example 1, except that the polyethyleneimine chain extender in the formulation is replaced with a conventional chain extender; that is, the polyurethane ink resin contains the following components in weight percentages (based on a total weight of 100 wt%):

[0159] Polyether polyol, 20 wt%;

[0160] Hydroxyl-terminated hydrogenated polybutadiene, 5 wt%;

[0161] Isocyanate, 5 wt%;

[0162] Chain extender, 2 wt%;

[0163] End-capping agent, 1 wt%;

[0164] Catalyst, 0.01 wt%;

[0165] Organic solvents, 66.99%; of which,

[0166] The polyether polyol is Wanhua Chemical's own raw material C2020, with a number average molecular weight of 2000.

[0167] Hydroxyl-terminated hydrogenated polybutadiene is GI-2000 from Nippon Soda Co., Ltd., with a number-average molecular weight of 2000.

[0168] The isocyanate is Wanhua Chemical's 4,4'-diphenylmethane diisocyanate (MDI-100);

[0169] The chain extender is isoflurane diamine;

[0170] The capping agent is di-n-butylamine;

[0171] The catalyst is stannous octoate;

[0172] The organic solvent is a mixture of ethyl acetate and isopropanol, with a mass ratio of ethyl acetate to isopropanol of 3:1.

[0173] The preparation method of polyurethane ink resin is as follows:

[0174] (a) First, add 20 kg of polyether polyol C2020 and 5 kg of hydroxyl-terminated hydrogenated polybutadiene GI-2000 to container A in sequence, turn on the stirrer to mix the materials evenly, then add 5 kg of MDI-100 and 0.01 kg of stannous octoate catalyst to it, mix evenly and heat to 70°C to react for 3 h to obtain the first reactant with NCO% = 2.1 wt%.

[0175] (b) Add 1 kg of the capping agent di-n-butylamine to the obtained first reactant, and after reacting for 0.5 h, a second reactant with NCO% = 0.98 wt% is obtained;

[0176] (c) Add 2 kg of isoflurane diamine chain extender, 50.24 kg of ethyl acetate and 16.75 kg of isopropanol to container B and stir for 0.5 h to mix them evenly; then add the second reactant obtained in container A to container B and react at room temperature for 1 h to obtain the polyurethane ink resin.

[0177] Comparative Example 3

[0178] The preparation method of the polyurethane ink resin is the same as in Example 1, except that the hydroxyl-terminated hydrogenated polybutadiene in the formulation is replaced with a conventional polyether polyol, and the polyethyleneimine is replaced with a conventional chain extender; that is, the polyurethane ink resin contains the following components in weight percentages (based on a total weight of 100 wt%):

[0179] Polyether polyol, 25 wt%;

[0180] Isocyanate, 5 wt%;

[0181] Chain extender, 2 wt%;

[0182] End-capping agent, 1 wt%;

[0183] Catalyst, 0.01 wt%;

[0184] Organic solvent, 66.99 wt%; of which,

[0185] The polyether polyol is Wanhua Chemical's C2020, with a number-average molecular weight of 2000.

[0186] The isocyanate is Wanhua Chemical's 4,4'-diphenylmethane diisocyanate (MDI-100);

[0187] The chain extender is isoflurane diamine;

[0188] The capping agent is di-n-butylamine;

[0189] The catalyst is stannous octoate;

[0190] The organic solvent is a mixture of ethyl acetate and isopropanol, with a mass ratio of ethyl acetate to isopropanol of 3:1.

[0191] Preparation method of polyurethane ink resin:

[0192] (a) First, add 25 kg of polyether polyol C2020 to container A, start stirring, then add 5 kg of MDI-100 and 0.01 kg of stannous octoate catalyst, mix evenly and heat to 70°C for 3 h to obtain the first reactant with NCO% = 2.1 wt%.

[0193] (b) Add 1 kg of the capping agent di-n-butylamine to the obtained first reactant, and after reacting for 0.5 h, a second reactant with NCO% = 0.98 wt% is obtained;

[0194] (c) Add 2 kg of isophorone diamine chain extender, 50.24 kg of ethyl acetate and 16.75 kg of isopropanol to container B and stir for 0.5 h to mix them evenly; then add the second reactant obtained in container A to container B and react at room temperature for 1 h to obtain the polyurethane ink resin.

[0195] Comparative Example 4

[0196] A commercially available polyurethane ink resin (Arakawa Chemical's F-409) is provided, which has a solid content of 40% and can be used to prepare solvent-based polyurethane inks.

[0197] Performance testing:

[0198] The high-performance polyurethane ink resins obtained in Examples 1-5 and the polyurethane ink resins obtained in Comparative Examples 1-4 were respectively prepared into composite inks for flexible packaging, and the performance of each composite ink was tested.

[0199] 1. Ink preparation:

[0200] Flexible packaging composite inks were prepared using the polyurethane ink resins obtained in Examples 1-5 and Comparative Examples 1-4, respectively. The ink formulations contained the following components in weight percentage:

[0201]

[0202] After mixing the above components in proportion, grind and disperse them in a grinder for 2 hours to obtain the composite ink samples to be tested.

[0203] 2. Performance Testing:

[0204] (1) Substrate adhesion test:

[0205] The composite inks obtained above were sampled on BOPP and PET substrates using an RK sampler. After drying, the substrate adhesion of the coating was tested according to GB / T 13217.7-2009. The ink adhesion was judged by a scale of 1 to 5, where 1 represents the worst adhesion and 5 represents the best adhesion.

[0206] (2) Anti-precipitation performance test:

[0207] The composite ink samples obtained above were placed in a constant temperature drying oven at 50℃ for 7 days. After taking them out, it was observed whether precipitation occurred in each ink sample. The anti-precipitation performance of the ink was judged by a grade of 1 to 5, where grade 1 represents the worst anti-precipitation performance and grade 5 represents the best anti-precipitation performance.

[0208] Table 1. Performance test results of inks prepared from various polyurethane ink resins.

[0209]

[0210] As shown in Table 1, the inks prepared from the polyurethane resins obtained in Examples 1-5 exhibit superior performance compared to the inks prepared from the polyurethane resins obtained in Comparative Examples 1 and 3. This indicates that the present invention, by introducing terminal hydroxyl hydrogenated polybutadiene into the polyurethane resin, can significantly improve the substrate adhesion (especially BOPP adhesion) of the obtained inks. Furthermore, the inks prepared from the polyurethane resins obtained in Examples 1-5 exhibit superior performance compared to the inks prepared from the polyurethane resins obtained in Comparative Examples 2 and 3. This indicates that the present invention, by introducing polyethyleneimine into the polyurethane resin, can significantly improve the anti-settling properties of the inks. Simultaneously, the inks prepared from the polyurethane resins obtained in Examples 1-5 exhibit superior performance compared to the inks prepared from the polyurethane resin obtained in Comparative Example 4. This demonstrates that the high-performance polyurethane ink resin obtained by the present invention also surpasses currently commercially available polyurethane ink resins in terms of BOPP adhesion and anti-settling properties, and can be used for the preparation of high-performance flexible packaging inks.

[0211] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the spirit of the invention.

Claims

1. A high-performance polyurethane ink resin, characterized in that, It contains the following components by weight percentage: Polyether polyol, 10-20 wt%; Hydroxyl-terminated hydrogenated polybutadiene, 5–15 wt%; Isocyanate, 5–15 wt%; Polyethyleneimine, 1–5 wt%; End-capping agent, 0.5wt% to 3wt%; Catalyst, 0.01wt%~0.5wt%; Organic solvent, 50-70 wt%.

2. The polyurethane ink resin according to claim 1, characterized in that, The polyether polyol is polyoxypropylene glycol; Preferably, the number average molecular weight of the polyoxypropylene glycol is 1000 to 4000.

3. The polyurethane ink resin according to claim 1 or 2, characterized in that, The number-average molecular weight of the hydroxyl-terminated hydrogenated polybutadiene is 1000–4000.

4. The polyurethane ink resin according to any one of claims 1-3, characterized in that, The isocyanate is selected from one or more of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, isoflurone diisocyanate, and hexamethylene diisocyanate.

5. The polyurethane ink resin according to any one of claims 1-4, characterized in that, The number-average molecular weight of the polyethyleneimine is 1000-2000.

6. The polyurethane ink resin according to any one of claims 1-5, characterized in that, The capping agent is a small molecule monoamine; preferably selected from one or more of ethanolamine, diethanolamine, n-butylamine and di-n-butylamine; The catalyst is selected from one or more of stannous octoate, dibutyltin dilaurate, and bismuth decanoate; The organic solvent is selected from one or more of ethyl acetate, n-propyl acetate, n-butyl acetate, ethanol, and isopropanol.

7. The method for preparing the polyurethane ink resin according to any one of claims 1-6, characterized in that, Includes the following steps: (a) Mix polyether polyol and hydrogenated polybutadiene with hydroxyl groups evenly, then add isocyanate and catalyst and heat to 70-100°C to react and obtain the first reactant containing NCO groups. (b) Add a capping agent to the first reactant and react to obtain a second reactant containing NCO groups; (c) Polyethyleneimine is mixed with an organic solvent to obtain a homogeneous mixture; the second reactant is then added to the homogeneous mixture, and the mixture is reacted at room temperature to obtain a polyurethane ink resin.

8. The preparation method according to claim 7, characterized in that, The reaction time after heating to 70-100°C in step (a) is 1-3 hours; the NCO content in the first reactant is 1.2 wt%-3.0 wt%. The reaction time after adding the capping agent in step (b) is 0.5 to 2 hours, and the NCO content in the second reactant is 0.5 wt% to 2.0 wt%.

9. The preparation method according to claim 7 or 8, characterized in that, The reaction time for step (c) at room temperature is 0.5 to 2 hours.

10. The application of the polyurethane ink resin according to any one of claims 1-6 or the polyurethane ink resin prepared by the preparation method according to any one of claims 7-9 in the field of flexible packaging printing inks.

Images