Polyurethane ink resin, preparation method thereof and ink

Abstract

The invention relates to the technical field of polymer chemistry, in particular to polyurethane ink resin, a preparation method of the polyurethane ink resin and ink, and the polyurethane ink resin is prepared by reacting the following raw materials in parts by weight: 15-26 parts of polyester polyol; 0.5 to 1.5 parts of an amine chain extender; 2 to 7 parts of isocyanate; 0.7 to 9 parts of an alcohol chain extender; the polyester resin comprises dimer alcohol, and the hydroxyl value of the polyester resin is 200-210 mKOH / g; the functional end-capping reagent is tertiary amine with one end containing a primary amine group or a secondary amine group and the other end containing a hydroxyl group and a tertiary amine group, and the mass ratio of the dimer alcohol to the polyester polyol is controlled to be (0.05-0.43): 1. Through the synergistic effect of the dimer alcohol and the functional end-capping reagent, the defects existing in the prior art are effectively overcome, the high ink dissolving resistance of the resin is achieved, and meanwhile the resin has excellent application performance such as printability, dispersity and membrane material adhesion.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer chemistry, and in particular to a polyurethane ink resin, a preparation method thereof, and ink. Background Art

[0002] Plastic flexible packaging printing primarily utilizes two printing methods: gravure and flexographic. Gravure is the oldest and most widely used printing method in the plastic flexible packaging sector. Gravure is popular in the packaging printing industry due to its high printing efficiency, ability to produce intricate patterns, and its appeal to Eastern aesthetics. Inks used in gravure printing can be categorized by the base resin type into polyurethane inks, acrylic inks, chlorinated polypropylene inks, and polyamide inks. Polyurethane inks, among others, are a key area of ​​development and application due to their adaptability to a wide range of substrates, integrated dry-light steaming and cooking, and versatility for surface printing and laminating. They account for over half of the gravure ink market share and continue to grow rapidly.

[0003] At the same time, driven by growing awareness of environmental protection and improved work efficiency, polyurethane solvent-free glue lamination has gradually replaced dry lamination as the mainstream lamination method. However, this also presents new challenges: while polyurethane solvent-free glue is environmentally friendly, it is limited by its low working viscosity and has a relatively low molecular weight. Polyester solvent-free glue, in particular, has a low molecular weight and a molecular structure that is more similar to ink resin. Therefore, during lamination, the ink is easily dissolved by the glue, causing discoloration of the pattern, which has become a difficulty and pain point in the industry.

[0004] Therefore, there is an urgent need to develop a polyurethane composite ink with excellent matching properties with solvent-free glue to improve the ink's dispersibility, film adhesion and anti-ink dissolving properties. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the polyurethane ink in the prior art, such as poor anti-ink dissolution performance, insufficient dispersibility and film adhesion, thereby providing a polyurethane ink resin, a preparation method thereof and ink.

[0006] The present application provides a polyurethane ink resin, which is prepared by using raw materials comprising the following parts by weight:

[0007] 15-26 parts of polyester polyol;

[0008] 0.5-1.5 parts of amine chain extender;

[0009] 2 to 7 parts of isocyanate;

[0010] 0.7 to 9 parts of an alcohol chain extender; comprising a dimer alcohol having a hydroxyl value of 200-210 mKOH / g;

[0011] 0.05 to 0.4 parts of a functional end-capping agent, which is a tertiary amine having a primary or secondary amino group at one end and a hydroxyl group and a tertiary amino group at the other end; and a mass ratio of the alcohol chain extender to the polyester polyol of 0.05 to 0.43:1.

[0012] Furthermore, the alcohol chain extender comprises bio-based dimer alcohol; optionally, the alcohol chain extender comprises Pripol 2030 and / or Pripol 2033.

[0013] Furthermore, the functional end-capping agent includes N,N-bis(2-hydroxyethyl)ethylenediamine, N-methyl-N-(2-hydroxyethyl)-1,3-propylenediamine, 2-((3-aminopropyl)(ethyl)amino)ethanol, N-(2-aminopropyl)diethanolamine, N-(3-aminopropyl)diethanolamine, 5-(N-ethyl-N-2-hydroxyethylamine)-2-pentylamine, 2-(1,4-diazepan-1-yl)ethanol, 1-amino-3-morpholino-2-propanol, 1,4'-bipiperidin-3-ol, (1-(3-aminopropyl) Preferably, the amine comprises one or more of: 1-(4-aminobutyl)pyrrolidin-2-yl)methanol, 1-(4-piperidinyl)-3-pyrrolidinol, 2-{3-[(methylamino)methyl]piperidin-1-yl}ethanol, and 2-(3-(aminomethyl)piperidin-1-yl)ethane-1-ol; preferably, the amine comprises one or more of: N,N-bis(2-hydroxyethyl)ethylenediamine, N-(2-aminopropyl)diethanolamine, N-(3-aminopropyl)diethanolamine, and 2-((3-aminopropyl)(ethyl)amino)ethanol.

[0014] Furthermore, the functionality of the polyester polyol is 2 to 3; and / or the number average molecular weight of the polyester polyol is 1000 to 6000; and / or the raw materials of the polyurethane ink resin also include a catalyst and / or a solvent.

[0015] Furthermore, the polyester polyol is a hydroxyl-terminated polyester polyol generated by polycondensation of a diol and a dibasic acid;

[0016] Preferably, the diol is one or more of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, methylpropylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexyl glycol, dihydroxydiphenyl sulfone, 2,2-bis(4-hydroxyphenyl)propane, and 4,4-dihydroxydiphenylmethane, more preferably one or more of methylpropylene glycol, 1,4-butanediol, neopentyl glycol, and 3-methyl-1,5-pentanediol;

[0017] Preferably, the dibasic acid is selected from one or more of sebacic acid, adipic acid, azelaic acid, terephthalic acid, isophthalic acid, and phthalic acid, more preferably adipic acid.

[0018] Furthermore, the isocyanate includes one or more of toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, cyclohexane dimethylene diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, and methylcyclohexyl diisocyanate; preferably includes one or more of isophorone diisocyanate, toluene diisocyanate, and dicyclohexylmethane diisocyanate.

[0019] Furthermore, the amine chain extender includes one or more of isophoronediamine, ethylenediamine, propylenediamine, 1,4-butanediamine, neopentyldiamine, 1,6-hexanediamine, octanediamine, decanediamine, dodecylamine, dicyclohexylmethanediamine, and 1,4-cyclohexenediamine, preferably isophoronediamine.

[0020] On the other hand, the present application provides a method for preparing any of the above-mentioned polyurethane ink resins, comprising the following steps:

[0021] Step S1: mixing polyester polyol, alcohol chain extender, isocyanate and solvent, and reacting to obtain a prepolymer;

[0022] In step S2, the prepolymer, the amine chain extender, the functional end-capping agent and the solvent are mixed to obtain the polyurethane ink resin.

[0023] Furthermore, in step S1, the reaction temperature is 60-120° C. and the reaction time is 3-5 hours; and / or, in step S2, an amine chain extender, a functional end-capping agent and a solvent are first mixed to prepare a chain extension solution, and the prepolymer is dropwise added to the chain extension solution to prepare a polyurethane ink resin; and / or, in step S1, a step of mixing a catalyst into the polyester polyol is also included before the reaction.

[0024] On the other hand, the present application also provides an ink, comprising any of the above-mentioned polyurethane ink resins or the polyurethane ink resins prepared by the preparation method.

[0025] The technical solution of the present invention has the following advantages:

[0026] The polyurethane ink resin provided by the present invention is prepared from the following raw materials in parts by weight: 15 to 26 parts of polyester polyol; 0.5 to 1.5 parts of amine chain extender; 2 to 7 parts of isocyanate; 0.7 to 9 parts of alcohol chain extender; the polyurethane ink resin includes a dimerol having a hydroxyl value of 200 to 210 mKOH / g; and 0.05 to 0.4 parts of a functional end-capping agent, which is a tertiary amine having a primary or secondary amine group at one end and a hydroxyl group and a tertiary amine group at the other end, and the mass ratio of the dimerol to the polyester polyol is controlled to be 0.05 to 0.43:1. By using the polyester polyol, the amine chain extender, the isocyanate, the alcohol chain extender containing the dimerol, and the functional end-capping agent in a specific ratio and controlling the mass ratio of the dimerol to the polyester polyol within the above range, the mechanical properties, dispersibility, and adhesion of the polyurethane resin can be enhanced, as well as its compatibility with solvent-free glue, thereby significantly improving the anti-ink performance of the polyurethane composite ink. The non-polar segments and hydrocarbon side chains of the dimer can alter the molecular polarity of the polyurethane ink resin. By using a dimer with a specific hydroxyl value range and controlling the mass ratio of the dimer to the polyester polyol within the aforementioned range, the polarity difference between the polyurethane ink resin and the solvent-free glue is increased, reducing the structural similarity between the polyurethane ink resin and the solvent-free glue, thereby improving the polyurethane ink resin's resistance to solvent-free glue. The hydroxyl and tertiary amine groups contained in the functional end-capping agent can enhance its affinity for pigments and printing substrates. The synergistic effect of the two effectively overcomes the shortcomings of existing technologies, achieving high resistance to ink dissolution of the resin while also maintaining excellent application properties such as printability, dispersibility, and film adhesion. DETAILED DESCRIPTION

[0027] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0028] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0029] On the one hand, polyurethane solvent-free adhesives are widely used in the flexible packaging field due to their environmentally friendly nature and excellent bonding properties. However, because solvent-free adhesives must meet low working viscosity requirements, their molecular weight is typically relatively low. This low molecular weight makes them susceptible to ink dissolution when compounded with polyurethane ink resins. This dissolution can cause discoloration and blurring of printed designs, seriously affecting the product's appearance quality and market competitiveness.

[0030] On the other hand, due to its molecular structure being similar to that of solvent-free glue, traditional polyurethane ink resins are difficult to effectively resist the dissolution of glue. Therefore, how to improve the anti-ink performance of ink resins has become a technical challenge that needs to be solved urgently in the industry.

[0031] To address these issues, developing a new type of polyurethane ink resin is crucial. This resin must not only be chemically distinct from solvent-free adhesives to improve ink resistance, but also meet the printing industry's multiple requirements for color and printability.

[0032] Based on this, in the first aspect, the polyurethane ink resin of the present invention is prepared by using raw materials comprising the following parts by weight: 15 to 26 parts of polyester polyol, 0.5 to 1.5 parts of amine chain extender, 2 to 7 parts of isocyanate, 0.7 to 9 parts of alcohol chain extender, and 0.05 to 0.4 parts of functional end-capping agent; the alcohol chain extender includes dimer alcohol, and the hydroxyl value is 200-210 mKOH / g; the functional end-capping agent is a tertiary amine containing a primary or secondary amine group at one end and a hydroxyl group and a tertiary amine group at the other end; the mass ratio of the alcohol chain extender to the polyester polyol is 0.05 to 0.43:1.

[0033] The polyurethane ink resin provided by the present invention includes a chain extender comprising a dimer alcohol, which improves the polyurethane ink resin's resistance to solvent-free glue, thereby enhancing the ink's pigment dispersibility, hiding power, and adhesion to substrates. The functional end-capping agent, comprising hydroxyl and tertiary amine groups, improves the ink's pigment dispersibility, anti-blocking properties, hiding power, and adhesion to substrates, reducing the risk of discoloration during printing.

[0034] Specifically, in the polyurethane ink resin provided by the present invention, the chain extender is a dimer alcohol, which is a macromolecule with a hydroxyl value of 200-210 mKOH / g. It usually contains a non-polar chain segment, which can change the molecular polarity of the polyurethane ink resin, increase the polarity difference between the polyurethane ink resin and the solvent-free glue, reduce the structural similarity between the polyurethane ink resin and the solvent-free glue, and thus improve the polyurethane ink resin's resistance to solvent-free glue. The functional end-capping agent is a tertiary amine containing a primary or secondary amine group at one end and a hydroxyl group and a tertiary amine group at the other end. This tertiary amine can change the polarity of the polyurethane ink resin and improve the polyurethane ink resin's resistance to solvent-free glue. This can improve the dispersibility of the pigment in the ink, anti-blocking properties, hiding properties, and adhesion to the substrate, reducing the risk of pattern discoloration during printing. The use of the functional end-capping agent can also adjust the rheological properties of the polyurethane ink resin, giving it better fluidity and stability during processing and application. The polyurethane ink resin of the present invention is resistant to solvent-free glue dissolution and has excellent comprehensive application performance.

[0035] In the polyurethane ink resin provided by the present invention, the isocyanate groups (-NCO) in the isocyanate raw material react with the hydroxyl groups (-OH) in the polyol to form polyurethane chains. This reaction is the basis for the formation of polyurethane. Through cross-linking, a polymer network with a certain molecular weight and structure is formed, enhancing the mechanical strength and chemical resistance of the polyurethane ink resin.

[0036] In the polyurethane ink resin provided by the present invention, the raw material amine chain extender reacts with isocyanate groups (-NCO) to form urea bonds (-NH-CO-NH), thereby extending and crosslinking the polyurethane chains. This reaction not only increases the molecular weight of the polymer but also improves the crosslink density of the polyurethane ink resin, enhancing its mechanical strength and chemical resistance.

[0037] In addition, the functional end-capping agent in the polyurethane ink resin provided by the present invention is used to terminate the polyurethane synthesis reaction, preventing excessive cross-linking or chain growth. Through end-capping, the molecular weight and structure of the polymer can be precisely controlled, thereby achieving the desired physical and chemical properties.

[0038] In the polyurethane ink resin provided by the present invention, the alcohol chain extender is dimerol, with a hydroxyl value of 200-210 mKOH / g. The non-polar chain segments and alkane side chains of the dimerol can change the molecular polarity of the polyurethane ink resin, increasing the polarity difference between the polyurethane ink resin and the solvent-free glue, reducing the structural similarity between the polyurethane ink resin and the solvent-free glue, thereby improving the polyurethane ink resin's resistance to solvent-free glue. The hydroxyl and tertiary amine groups contained in the functional end-capping agent can enhance the affinity for pigments and printing substrates. The synergistic effect of the two effectively overcomes the shortcomings of the existing technology, achieving high ink resistance of the resin while also having excellent application properties such as printability, dispersibility, and film adhesion.

[0039] In some embodiments of the present invention, the dimer alcohol comprises Pripol 2030 and / or Pripol 2033.

[0040] The dimer alcohol of the present invention includes Pripol 2030 and / or Pripol 2033. Pripol 2030 and Pripol 2033 have a six-membered ring structure and an alkane side chain, that is, the introduction of a non-polar segment and an alkane side chain can change the molecular structure, reduce the structural similarity between the polyurethane ink resin and the solvent-free glue, and thus improve the ink-dissolving performance of the polyurethane ink resin against the solvent-free glue.

[0041] In some embodiments of the present invention, the functional end-capping agent is a tertiary amine containing a primary or secondary amino group at one end and a hydroxyl group and a tertiary amino group at the other end, including N, N-bis (2-hydroxyethyl) ethylenediamine, N-methyl-N- (2-hydroxyethyl) -1,3-propylenediamine, 2- ((3-aminopropyl) (ethyl) amino) ethanol, N- (2-aminopropyl) diethanolamine, N- (3-aminopropyl) diethanolamine, 5- (N-ethyl-N-2-hydroxyethylamine) -2-pentylamine, 2- (1,4-diazepan-1-yl) ethanol, 1-amino-3-morpholino-2-propanol, 1,4'- Piperidin-3-ol, (1-(3-aminopropyl)pyrrolidin-2-yl)methanol, 1-(4-aminobutyl)pyrrolidin-2-yl]methanol, 1-(4-piperidinyl)-3-pyrrolidinol, 2-{3-[(methylamino)methyl]piperidin-1-yl}ethanol, 2-(3-(aminomethyl)piperidin-1-yl)ethane-1-ol one or more; preferably including N,N-bis(2-hydroxyethyl)ethylenediamine, N-(2-aminopropyl)diethanolamine, N-(3-aminopropyl)diethanolamine, 2-((3-aminopropyl)(ethyl)amino)ethanol one or more.

[0042] The functional end-capping agent in this invention is a tertiary amine containing a primary or secondary amino group at one end and a hydroxyl group and a tertiary amino group at the other. By introducing this tertiary amine into the ends of the polyurethane ink resin molecules, the polarity of the polyurethane ink resin can be altered, thereby improving the dispersibility of the pigment in the ink, anti-blocking properties, hiding properties, and adhesion to the substrate, while reducing the risk of color transfer and discoloration during printing. Furthermore, the use of the functional end-capping agent can adjust the rheological properties of the polyurethane ink resin, resulting in improved fluidity and stability during processing and application.

[0043] In some embodiments of the present invention, the polyester polyol functionality is 2 to 3, preferably 2;

[0044] The number average molecular weight of the polyester polyol is 1,000 to 6,000, preferably 2,000 to 4,000.

[0045] In the present invention, the functionality and number-average molecular weight of the polyester polyol within the above-mentioned ranges can adjust the hardness, flexibility, and elasticity of the polyurethane ink resin, helping to control the crosslink density of the polyurethane ink resin. A moderate crosslink density can improve the polyurethane ink resin's mechanical properties, such as tensile strength and tear resistance. It can also enhance the polyurethane ink resin's chemical resistance, maintaining stability when exposed to solvents and other chemicals. Furthermore, it can improve the polyurethane ink resin's fluidity and pigment dispersibility, ensuring the ink's color uniformity and hiding power. It also helps to form a uniform polymer network, improving the ink's adhesion to the substrate and ensuring the durability and quality of the printed product.

[0046] In some embodiments of the present invention, the polyester polyol is a hydroxyl-terminated polyester polyol generated by the condensation of a diol and a dibasic acid; preferably, the diol is one or more of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, methylpropylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexyl glycol, dihydroxydiphenyl sulfone, 2,2-bis(4-hydroxyphenyl)propane, and 4,4-dihydroxydiphenylmethane, more preferably one or more of methylpropylene glycol, 1,4-butanediol, neopentyl glycol, and 3-methyl-1,5-pentanediol; the dibasic acid is one or more selected from sebacic acid, adipic acid, azelaic acid, terephthalic acid, isophthalic acid, and phthalic acid, more preferably adipic acid.

[0047] The diols mentioned above in the present invention can adjust the flexibility and hardness of the polyester polyol, thereby affecting the viscosity and rheological properties of the polyurethane ink resin, making it easier to process and apply.

[0048] The dibasic acid in the present invention can enhance the mechanical properties of the polyurethane ink resin, such as tensile strength and tear resistance. It also affects the polarity and surface energy of the polyurethane ink resin, thereby improving the dispersibility of the pigment in the ink and the adhesion to the substrate.

[0049] In some embodiments of the present invention, the isocyanate includes at least one of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), 1,4-cyclohexane diisocyanate (CHDI), cyclohexane dimethylene diisocyanate (HXDI), trimethyl-1,6-hexamethylene diisocyanate (TMHDI), and methylcyclohexyl diisocyanate (HTDI); preferably includes at least any one of isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), and dicyclohexylmethane diisocyanate (HMDI).

[0050] The isocyanate in the present invention can further enhance the mechanical properties, dispersibility and adhesion of the polyurethane resin.

[0051] In some embodiments of the present invention, the amine chain extender includes one or more of isophoronediamine, ethylenediamine, propylenediamine, 1,4-butanediamine, neopentyldiamine, 1,6-hexanediamine, octanediamine, decanediamine, dodecylamine, dicyclohexylmethanediamine, and 1,4-cyclohexenediamine, preferably isophoronediamine.

[0052] The amine chain extender in the present invention can further enhance the mechanical properties, hiding properties and adhesion of the polyurethane resin.

[0053] In a second aspect, the present invention provides a method for preparing the polyurethane ink resin as described above, comprising the following steps:

[0054] Step S1: mixing polyester polyol, alcohol chain extender, isocyanate and solvent, and reacting to obtain a prepolymer;

[0055] In step S2, the prepolymer, the amine chain extender, the functional end-capping agent and the solvent are mixed to obtain the polyurethane ink resin.

[0056] In some embodiments of the present invention, the reaction temperature is 60-120° C., and the reaction time is 3-5 hours; and / or, in step S2, an amine chain extender, a functional end-capping agent, and a solvent are first mixed to prepare a chain extension solution, and the prepolymer is dropwise added to the chain extension solution to prepare a polyurethane ink resin; and / or, in step S1, a step of mixing a catalyst into the polyester polyol before the reaction is further included.

[0057] In some embodiments of the present invention, the solvent includes esters and / or alcohols, for example, secondary alcohols, tertiary alcohols; preferably includes at least one of ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, and isopropanol; more preferably includes at least one of ethyl acetate, n-propyl acetate, and isopropanol.

[0058] In some embodiments of the present invention, the catalyst can be a catalyst commonly used in the art, including but not limited to dimethyltin diacetate, dibutyltin dibutyrate, dibutyltin di(2-ethylhexanoate), dibutyltin dilaurate, dioctyltin dilaurate, zinc (II) dioctoate, zirconium acetylacetonate, 2,2,6,6-tetramethyl-3,5-heptanedione zirconium, bismuth neodecanoate and bismuth 2-ethylhexanoate; preferably dibutyltin dilaurate, bismuth neodecanoate and bismuth 2-ethylhexanoate, more preferably bismuth neodecanoate. The amount of the catalyst added can be the conventional amount used in the art.

[0059] In some embodiments of the present invention, the method for preparing the polyurethane ink resin comprises the following steps:

[0060] 1) reacting a prepolymerized portion comprising a polyester polyol, an alcohol chain extender, an isocyanate, a catalyst, and a first solvent at 60-120° C. for 3-5 hours, cooling the mixture to below 70° C. and adding a second solvent to obtain a prepolymer solution;

[0061] 2) adding the prepolymer solution obtained in step 1) to a chain extender solution comprising an amine chain extender, a functional end-capping agent and a third solvent within 0.5 to 2 hours to prepare the polyurethane ink resin.

[0062] In the preparation method of the polyurethane ink resin of the present invention, the first solvent and the second solvent may be the same or different, the second solvent and the third solvent may be the same or different, and the first solvent and the third solvent may be the same or different.

[0063] In step 1), the first solvent comprises an ester and / or an alcohol, such as a secondary alcohol or a tertiary alcohol; preferably, it comprises at least one of ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, and isopropyl alcohol; more preferably, it comprises at least one of ethyl acetate, n-propyl acetate, and isopropyl alcohol. The second solvent comprises an ester and / or an alcohol, such as a secondary alcohol or a tertiary alcohol; preferably, it comprises at least one of ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, and isopropyl alcohol; more preferably, it comprises at least one of ethyl acetate, n-propyl acetate, and isopropyl alcohol. The polyester polyol can be prepared according to methods known in the art. For example, a diol, a dibasic acid, and tetrabutyl titanate (as a catalyst) are added to a reactor, nitrogen is introduced, and the reaction is stirred at 160°C to 280°C for 24 to 36 hours to produce the polyester polyol.

[0064] A first system including polyester polyol, dimer, isocyanate, catalyst and first solvent is put into a container, and an inert gas, such as nitrogen, is introduced. After reacting at 60°C to 120°C for 3h to 5h, the temperature is lowered to below 70°C. Then, a second solvent is added to the cooled first system. The addition of the second solvent can reduce the viscosity of the first system to obtain a prepolymer solution.

[0065] In step 2), the third solvent comprises an ester and / or an alcohol, such as a secondary alcohol or a tertiary alcohol; preferably, it comprises at least one of ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, and isopropyl alcohol; more preferably, it comprises at least one of ethyl acetate, n-propyl acetate, and isopropyl alcohol. The amine chain extender, functional end-capping agent, and third solvent are uniformly stirred to form a second system. The prepolymer solution is then added dropwise to the second system over a period of 0.5 to 2 hours while stirring at room temperature. This controls the polymerization rate of the polyurethane ink resin and produces the polyurethane ink resin.

[0066] The polyurethane ink resin of the present invention is resistant to solvent-free glue dissolution and exhibits excellent overall application performance. This resin not only exhibits outstanding resistance to solvent-free glue dissolution, but also exhibits good pigment dispersibility, high hiding power, and excellent substrate adhesion, effectively overcoming the shortcomings of prior art in terms of ink dissolution resistance and uneven performance.

[0067] In a third aspect, the present invention provides an ink comprising the polyurethane ink resin as described above or the polyurethane ink resin prepared according to the preparation method as described above.

[0068] The ink provided by the present invention can be a solvent-based gravure composite ink, including the above-mentioned polyurethane ink resin. Therefore, the ink has good resistance to glue dissolution, pigment dispersibility, hiding performance, and strong substrate adhesion.

[0069] The raw materials used in the embodiments and comparative examples are as follows:

[0070] Isocyanate: isophorone diisocyanate, IPDI, Wanhua Chemical;

[0071] Isocyanate: toluene diisocyanate, TDI-80, Wanhua Chemical;

[0072] Isocyanate: dicyclohexylmethane diisocyanate, HMDI, Wanhua Chemical;

[0073] Alcohol chain extender: dimer alcohol, Pripol2030, Pripol2033, Cargill;

[0074] Alcohol chain extender: 1,4-butanediol, BDO, Wanhua Chemical;

[0075] Polyester polyol: Polyester HD7740, obtained by reacting adipic acid and methylpropylene glycol, with a number average molecular weight of 4000, provided by Shanghai Huide Technology Co., Ltd.

[0076] Polyester polyol: Polyester HD3320, obtained by reacting adipic acid and neopentyl glycol, number average molecular weight 2000, provided by Shanghai Huide Technology Co., Ltd.

[0077] Polyester polyol: Polyester HD4440, obtained by reacting adipic acid and 1,4-butanediol, with a number average molecular weight of 4000, provided by Shanghai Huide Technology Co., Ltd.

[0078] Polyester polyol: Polyester HD5520M, obtained by reacting adipic acid and 3-methyl-1,5-pentanediol, number average molecular weight 2000, provided by Shanghai Huide Technology Co., Ltd.

[0079] Catalyst: BICAT8118, organic bismuth catalyst, Leading Chemical, USA;

[0080] Amine chain extender: isophorone diamine, IPDA, Wanhua Chemical;

[0081] Functional end-capping agent: N,N-bis(2-hydroxyethyl)ethylenediamine, BHEDA, Inokane;

[0082] Functional capping agent: N-(2-aminopropyl)diethanolamine, IPEDEA, Inokane;

[0083] Functional capping agent: N-(3-aminopropyl)diethanolamine, BHPDA, Inokane;

[0084] Functional capping agent: 2-((3-aminopropyl)(ethyl)amino)ethanol, APEAE, Inokane;

[0085] Functional capping agent: N,N-dimethylethylenediamine, DMEDA, Inokane;

[0086] Functional capping agent: ethanolamine, EOA, Inokane;

[0087] Solvent: ethyl acetate, EA, Jiangmen Qianxin Chemical;

[0088] Solvent: Isopropyl alcohol, IPA, Jinzhou Petrochemical;

[0089] Titanium dioxide: R982, Sichuan Longmang;

[0090] Chlorovinyl resin: T5HX, Kanebuchi, Japan;

[0091] Matting powder: Sipernat820A, Degussa;

[0092] Wax powder: Ceridust3620, Clariant.

[0093] Example 1

[0094] This embodiment provides a polyurethane ink resin, the raw material composition of which is as follows:

[0095]

[0096] The preparation method is as follows:

[0097] Weigh polyester polyol, alcohol chain extender, isocyanate, catalyst, and 30 g of EA according to the amounts in the table above. Place the raw materials into a flask, purge with nitrogen, and react at 75°C for 5 hours. Cool to below 70°C and add 50 g of EA to obtain a prepolymer solution.

[0098] According to the amounts in the table above, an amine chain extender, a functional end-capping agent, 127.3 g of EA, and 69.1 g of IPA were weighed and placed in another flask. The raw materials were stirred to obtain a chain extension solution. The prepolymer solution was then added dropwise to the chain extension solution under stirring at room temperature over a period of 0.5 hours to obtain a polyurethane ink resin Eg1.

[0099] Example 2

[0100] This embodiment provides a polyurethane ink resin, the raw material composition of which is as follows:

[0101]

[0102] The preparation method is as follows:

[0103] Weigh polyester polyol, alcohol chain extender, isocyanate, catalyst, and 30 g of EA according to the amounts in the table above. Place the raw materials into a flask, purge with nitrogen, and react at 75°C for 5 hours. Cool to below 70°C and add 50 g of EA to obtain a prepolymer solution.

[0104] According to the amounts in the table above, weigh the amine chain extender, functional end-capping agent, 132.2 g of EA, and 70.7 g of IPA, put these raw materials into another flask, stir well to obtain a chain extension solution, and then add the above prepolymer solution dropwise to the chain extension solution under stirring at room temperature over 0.5 hours to obtain the polyurethane ink resin Eg2.

[0105] Example 3

[0106] This embodiment provides a polyurethane ink resin, the raw material composition of which is as follows:

[0107]

[0108] The preparation method is as follows:

[0109] Weigh polyester polyol, alcohol chain extender, isocyanate, catalyst, and 30 g of EA according to the amounts in the table above. Place the raw materials into a flask, purge with nitrogen, and react at 75°C for 5 hours. Cool to below 70°C and add 50 g of EA to obtain a prepolymer solution.

[0110] According to the amounts in the table above, weigh an amine chain extender, a functional end-capping agent, 135.7 g of EA, and 71.9 g of IPA. Put these raw materials into another flask and stir well to obtain a chain extension solution. Then, under stirring at room temperature, add the above prepolymer solution dropwise to the chain extension solution over 0.5 hours to obtain a polyurethane ink resin Eg3.

[0111] Example 4

[0112] This embodiment provides a polyurethane ink resin, the raw material composition of which is as follows:

[0113]

[0114] The preparation method is as follows:

[0115] Weigh polyester polyol, alcohol chain extender, isocyanate, catalyst, and 30 g of EA according to the amounts in the table above. Place the raw materials into a flask, purge with nitrogen, and react at 75°C for 5 hours. Cool to below 70°C and add 50 g of EA to obtain a prepolymer solution.

[0116] According to the amounts in the table above, weigh an amine chain extender, a functional end-capping agent, 137.6 g of EA, and 72.5 g of IPA. Put these raw materials into another flask and stir well to obtain a chain extension solution. Then, under stirring at room temperature, add the above prepolymer solution dropwise to the chain extension solution over 0.5 hours to prepare polyurethane ink resin Eg4.

[0117] Example 5

[0118] This embodiment provides a polyurethane ink resin, the raw material composition of which is as follows:

[0119]

[0120] The preparation method is as follows:

[0121] Weigh polyester polyol, alcohol chain extender, isocyanate, catalyst, and 30 g of EA according to the amounts in the table above. Place the raw materials into a flask, purge with nitrogen, and react at 75°C for 5 hours. Cool to below 70°C and add 50 g of EA to obtain a prepolymer solution.

[0122] According to the amounts in the table above, weigh an amine chain extender, a functional end-capping agent, 140.7 g of EA, and 73.6 g of IPA. Put these raw materials into another flask and stir well to obtain a chain extension solution. Then, under stirring at room temperature, add the above prepolymer solution dropwise to the chain extension solution over 0.5 hours to prepare the polyurethane ink resin Eg5.

[0123] Example 6

[0124] This embodiment provides a polyurethane ink resin, the raw material composition of which is as follows:

[0125]

[0126] The preparation method is as follows:

[0127] Weigh polyester polyol, alcohol chain extender, isocyanate, catalyst, and 30 g of EA according to the amounts in the table above. Place the raw materials into a flask, purge with nitrogen, and react at 75°C for 5 hours. Cool to below 70°C and add 50 g of EA to obtain a prepolymer solution.

[0128] According to the amounts in the table above, weigh an amine chain extender, a functional end-capping agent, 132.3 g of EA, and 70.8 g of IPA. Put these raw materials into another flask and stir well to obtain a chain extension solution. Then, under stirring at room temperature, add the above prepolymer solution dropwise to the chain extension solution over 0.5 hours to obtain a polyurethane ink resin Eg6.

[0129] Example 7

[0130] This embodiment provides a polyurethane ink resin, the raw material composition of which is as follows:

[0131]

[0132] The preparation method is as follows:

[0133] Weigh polyester polyol, alcohol chain extender, isocyanate, catalyst, and 30 g of EA according to the amounts in the table above. Place the raw materials into a flask, purge with nitrogen, and react at 75°C for 5 hours. Cool to below 70°C and add 50 g of EA to obtain a prepolymer solution.

[0134] According to the amounts in the table above, weigh an amine chain extender, a functional end-capping agent, 144.3 g of EA, and 74.8 g of IPA. Put these raw materials into another flask and stir to obtain a chain extension solution. Then, under stirring at room temperature, add the above prepolymer solution dropwise to the chain extension solution over 0.5 hours to obtain a polyurethane ink resin Eg7.

[0135] Example 8

[0136] This embodiment provides a polyurethane ink resin, the raw material composition of which is as follows:

[0137]

[0138] The preparation method is as follows:

[0139] Weigh polyester polyol, alcohol chain extender, isocyanate, catalyst, and 30 g of EA according to the amounts in the table above. Place the raw materials into a flask, purge with nitrogen, and react at 75°C for 5 hours. Cool to below 70°C and add 50 g of EA to obtain a prepolymer solution.

[0140] According to the amounts in the table above, weigh an amine chain extender, a functional end-capping agent, 131.9 g of EA, and 70.6 g of IPA. Put these raw materials into another flask and stir well to obtain a chain extension solution. Then, under stirring at room temperature, add the above prepolymer solution dropwise to the chain extension solution over 0.5 hours to prepare polyurethane ink resin Eg8.

[0141] Comparative Example 1

[0142] This comparative example provides a polyurethane ink resin, using the same amount of DMEDA as a functional end-capping agent instead of BHEDA as a functional end-capping agent. Specifically, the raw material composition of the polyurethane ink resin in this comparative example is as follows:

[0143]

[0144] The preparation method is as follows:

[0145] Weigh polyester polyol, alcohol chain extender, isocyanate, catalyst, and 30 g of EA according to the amounts in the table above. Place the raw materials into a flask, purge with nitrogen, and react at 75°C for 5 hours. Cool to below 70°C and add 50 g of EA to obtain a prepolymer solution.

[0146] An amine chain extender, a functional end-capping agent, 131.7 g of EA, and 70.6 g of IPA were weighed according to the amounts in the table above. These raw materials were placed in another flask and stirred to obtain a chain extension solution. The prepolymer solution was then added dropwise to the chain extension solution under stirring at room temperature over 0.5 hours to produce polyurethane ink resin C1.

[0147] Comparative Example 2

[0148] This comparative example provides a polyurethane ink resin, using BDO as an alcohol chain extender. The raw material composition of this comparative example is as follows:

[0149]

[0150] The preparation method is as follows:

[0151] Weigh polyester polyol, alcohol chain extender, isocyanate, catalyst, and 30 g of EA according to the amounts in the table above. Place the raw materials into a flask, purge with nitrogen, and react at 75°C for 5 hours. Cool to below 70°C and add 50 g of EA to obtain a prepolymer solution.

[0152] According to the amounts in the table above, an amine chain extender, a functional end-capping agent, 138.3 g of EA, and 72.8 g of IPA were weighed and placed in another flask. The raw materials were stirred to obtain a chain extension solution. The prepolymer solution was then added dropwise to the chain extension solution under stirring at room temperature over 0.5 hours to obtain polyurethane ink resin C2.

[0153] Comparative Example 3

[0154] This comparative example provides a polyurethane ink resin, using the same amount of EOA as a functional end-capping agent instead of BHEDA as a functional end-capping agent. Specifically, the raw material composition of the polyurethane ink resin in this comparative example is as follows:

[0155]

[0156] The preparation method is as follows:

[0157] Weigh polyester polyol, alcohol chain extender, isocyanate, catalyst, and 30 g of EA according to the amounts in the table above. Place the raw materials into a flask, purge with nitrogen, and react at 75°C for 5 hours. Cool to below 70°C and add 50 g of EA to obtain a prepolymer solution.

[0158] According to the amounts in the table above, an amine chain extender, a functional end-capping agent, 131.5 g of EA, and 70.5 g of IPA were weighed and placed in another flask. The raw materials were stirred to obtain a chain extension solution. The prepolymer solution was then added dropwise to the chain extension solution under stirring at room temperature over 0.5 hours to obtain polyurethane ink resin C3.

[0159] Comparative Example 4

[0160] This embodiment provides a polyurethane ink resin, the raw material composition of which is as follows:

[0161]

[0162]

[0163] The preparation method is as follows:

[0164] Weigh polyester polyol, alcohol chain extender, isocyanate, catalyst, and 30 g of EA according to the amounts in the table above. Place the raw materials into a flask, purge with nitrogen, and react at 75°C for 5 hours. Cool to below 70°C and add 50 g of EA to obtain a prepolymer solution.

[0165] According to the amounts in the table above, weigh the amine chain extender, functional end-capping agent, 136.3 g of EA, and 72.1 g of IPA. Put these raw materials into another flask and stir them to obtain a chain extension solution. Then, under stirring at room temperature, add the above prepolymer solution dropwise to the chain extension solution over 0.5 hours to prepare the polyurethane ink resin EgC4.

[0166] Comparative Example 5

[0167] This comparative example provides a polyurethane ink resin, the raw material composition of which is as follows:

[0168]

[0169] The preparation method is as follows:

[0170] Weigh polyester polyol, alcohol chain extender, isocyanate, catalyst, and 30 g of EA according to the amounts in the table above. Place the raw materials into a flask, purge with nitrogen, and react at 75°C for 5 hours. Cool to below 70°C and add 50 g of EA to obtain a prepolymer solution.

[0171] An amine chain extender, a capping agent, 139.0 g of EA, and 73.0 g of IPA were weighed according to the amounts in the table above. These raw materials were placed in another flask and stirred to obtain a chain extension solution. The prepolymer solution was then added dropwise to the chain extension solution under stirring at room temperature over 0.5 hours to obtain polyurethane ink resin C5.

[0172] Test Case

[0173] The polyurethane resins obtained in each embodiment and each comparative example were respectively prepared into inks according to the formulations in Table 1. The raw materials were placed in a 500 ml iron can, and an equal amount of 1 mm diameter glass beads were added. After sealing, the cans were ground in a paint rapid mixer for 3 to 4 hours to obtain polyurethane inks for gravure printing.

[0174] Table 1 Polyurethane gravure ink formula

[0175] raw material Parts by weight polyurethane resin 30 Titanium dioxide 31 Vinyl chloride resin 2.5 matting powder 0.4 wax powder 0.2 n-propyl acetate 22 Isopropyl alcohol 2 Ethyl acetate 11.9 total 100

[0176] The prepared polyurethane ink for gravure printing was tested as follows:

[0177] (1) Ink gloss test method

[0178] Use a wire rod to apply ink on a polyester (PET) film so that the dry film thickness of the applied ink layer is 2 to 3 μm; after drying the ink film with a hair dryer, observe the state of the coated surface and evaluate the gloss of the ink.

[0179] The evaluation criteria are: ◎ indicates good gloss; ○ indicates fair gloss; and × indicates poor gloss.

[0180] (2) Ink adhesion test method

[0181] Refer to GB / T13217.7-2009.

[0182] The plastic films are polyester film (PET) with corona treatment on the surface and biaxially oriented polypropylene film (BOPP).

[0183] The evaluation criteria are: ◎ indicates that the ink remains more than 90%; ○ indicates that the ink remains 60-90%; × indicates that the ink remains less than 50%.

[0184] (3) Ink resolubility test method

[0185] The ink was proofed using a KPP gravure ink proofer (produced by RK Company, UK, with a printing plate of 150 lines / inch). After the ink on the printing plate dried, about 1 to 2 grams of the test solvent was quickly dropped on the ink layer of the printing plate using a dropper, and then the time was counted; after 30 seconds, the solvent was blown away with a hair dryer to expose the solvent-covered ink layer and printing plate, and the dissolution of the ink layer was observed.

[0186] Evaluation criteria for the resolubility of ink film: ◎ indicates that the ink layer is obviously dissolved and the printing plate is relatively clean; ○ indicates that the ink layer is partially dissolved and the printing plate is not clean; × indicates that the ink layer is obviously not dissolved.

[0187] (4) Solvent-free glue leveling test

[0188] Use the KPP gravure ink proofer to proof the ink. After the ink on the printing plate is dry, use the KPP gravure ink proofer to apply solvent-free composite glue. Observe the state of the coated surface. The higher the gloss, the better the glue leveling.

[0189] The evaluation criteria are: ◎ indicates good leveling; ○ indicates fair leveling; and × indicates poor leveling.

[0190] (5) Solvent-free glue ink dissolution test

[0191] The ink was proofed using a KPP gravure ink proofer. After the ink on the printing plate dried, the solvent-free composite glue was also applied using the KPP gravure ink proofer. The plate was then laminated with a PET aluminized film and the ink layer was observed after 30 minutes.

[0192] The evaluation criteria are: ◎ indicates good solvent-resistant ink; ○ indicates average solvent-resistant ink; and × indicates poor solvent-resistant ink.

[0193] (6) The ink viscosity test standard is GB / T13217.4-91.

[0194] (7) The ink fineness test standard is GB / T13217.3-91.

[0195] (8) The hiding power test standard of ink is GB / T13217.6-2008, wherein the hiding power test standard sample is the ink prepared by the formula of Example 1.

[0196] The test results are shown in Table 2.

[0197] Table 2 Test results

[0198]

[0199] As can be seen from Table 3, compared with Comparative Examples 1-5, the polyurethane ink resin provided by each embodiment of the present invention, by adopting specific dimer and functional capping agent and controlling the amount of the two, exerts a synergistic effect to effectively overcome the defects of the prior art, achieves high anti-ink dissolving performance of the resin, and at the same time has excellent application performance, such as dispersibility and film adhesion.

[0200] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A polyurethane ink resin, characterized in that, The polyurethane ink resin is prepared by using raw materials comprising the following parts by weight: 15-26 parts of polyester polyol; 0.5-1.5 parts of amine chain extender; 2 to 7 parts of isocyanate; 0.7 to 9 parts of an alcohol chain extender; comprising a dimer alcohol having a hydroxyl value of 200-210 mKOH / g; 0.05 to 0.4 parts of a functional end-capping agent, which is a tertiary amine having a primary or secondary amino group at one end and a hydroxyl group and a tertiary amino group at the other end; and a mass ratio of the alcohol chain extender to the polyester polyol of 0.05 to 0.43:

1.

2. The polyurethane ink resin according to claim 1, characterized in that The alcohol chain extender comprises bio-based dimer alcohol; optionally, the alcohol chain extender comprises Pripol 2030 and / or Pripol 2033.

3. The polyurethane ink resin according to claim 1 or 2, characterized in that The functional end-capping agents include N,N-bis(2-hydroxyethyl)ethylenediamine, N-methyl-N-(2-hydroxyethyl)-1,3-propylenediamine, 2-((3-aminopropyl)(ethyl)amino)ethanol, N-(2-aminopropyl)diethanolamine, N-(3-aminopropyl)diethanolamine, 5-(N-ethyl-N-2-hydroxyethylamine)-2-pentylamine, 2-(1,4-diazepan-1-yl)ethanol, 1-amino-3-morpholino-2-propanol, 1,4'-bipiperidin-3-ol, (1-(3-aminopropyl) Preferably, the present invention comprises one or more of 1-(4-aminobutyl)pyrrolidin-2-yl)methanol, 1-(4-piperidinyl)-3-pyrrolidinol, 2-{3-[(methylamino)methyl]piperidin-1-yl}ethanol, and 2-(3-(aminomethyl)piperidin-1-yl)ethane-1-ol; preferably, the present invention comprises one or more of N,N-bis(2-hydroxyethyl)ethylenediamine, N-(2-aminopropyl)diethanolamine, N-(3-aminopropyl)diethanolamine, and 2-((3-aminopropyl)(ethyl)amino)ethanol.

4. The polyurethane ink resin according to any one of claims 1 to 3, characterized in that: The functionality of the polyester polyol is 2 to 3; and / or the number average molecular weight of the polyester polyol is 1000 to 6000; and / or the raw materials of the polyurethane ink resin further include a catalyst and / or a solvent.

5. The polyurethane ink resin according to any one of claims 1 to 4, characterized in that: The polyester polyol is a hydroxyl-terminated polyester polyol generated by polycondensation of a diol and a dibasic acid; Preferably, the diol is one or more of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, methylpropylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexyl glycol, dihydroxydiphenyl sulfone, 2,2-bis(4-hydroxyphenyl)propane, and 4,4-dihydroxydiphenylmethane, more preferably one or more of methylpropylene glycol, 1,4-butanediol, neopentyl glycol, and 3-methyl-1,5-pentanediol; Preferably, the dibasic acid is selected from one or more of sebacic acid, adipic acid, azelaic acid, terephthalic acid, isophthalic acid, and phthalic acid, more preferably adipic acid.

6. The polyurethane ink resin according to any one of claims 1 to 5, characterized in that: The isocyanate includes one or more of toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, cyclohexane dimethylene diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, and methylcyclohexyl diisocyanate; preferably includes one or more of isophorone diisocyanate, toluene diisocyanate, and dicyclohexylmethane diisocyanate.

7. The polyurethane ink resin according to any one of claims 1 to 6, characterized in that: The amine chain extender includes one or more of isophoronediamine, ethylenediamine, propylenediamine, 1,4-butanediamine, neopentyldiamine, 1,6-hexanediamine, octanediamine, decanediamine, dodecylamine, dicyclohexylmethanediamine, and 1,4-cyclohexenediamine, preferably isophoronediamine.

8. A method for preparing the polyurethane ink resin according to any one of claims 1 to 7, characterized in that: The steps include: Step S1: mixing polyester polyol, alcohol chain extender, isocyanate and solvent, and reacting to obtain a prepolymer; In step S2, the prepolymer, the amine chain extender, the functional end-capping agent and the solvent are mixed to obtain the polyurethane ink resin.

9. The method for preparing the polyurethane ink resin according to claim 8, wherein: In step S1, the reaction temperature is 60-120° C. and the reaction time is 3-5 hours; and / or, in step S2, an amine chain extender, a functional end-capping agent and a solvent are first mixed to prepare a chain extension solution, and the prepolymer is dropwise added to the chain extension solution to prepare a polyurethane ink resin; and / or, in step S1, a step of mixing a catalyst into the polyester polyol before the reaction is further included.

10. An ink, characterized in that: The invention comprises the polyurethane ink resin according to any one of claims 1 to 7 or the polyurethane ink resin prepared by the preparation method according to claim 8 or 9.

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