A polyurethane ink resin, its preparation method and use

Abstract

The application provides a polyurethane ink resin and a preparation method and application thereof, and the polyurethane ink resin is prepared from raw materials including the following components by mass: 18-34 parts of polyester polyol, 2-8 parts of isocyanate, 0.3-6 parts of amine chain extender, and 0.05-5 parts of end-capping agent; the polyester polyol is prepared by polycondensation of dihydric alcohol and diacid; and the dihydric alcohol includes dimeric alcohol. In the polyurethane ink resin, the dihydric alcohol for preparing the polyester polyol includes dimeric alcohol; the dimeric alcohol is a macromolecule and usually contains a non-polar segment; the molecular polarity of the polyurethane ink resin can be changed, the polarity difference between the polyurethane ink resin and solvent-free glue is increased, the structural similarity between the polyurethane ink resin and the solvent-free glue is reduced, the ink resistance of the polyurethane ink resin to the solvent-free glue is improved, and then the pigment dispersibility, hiding property and adhesion to a substrate of the ink can be improved.

Description

Technical Field

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

[0002] With advancements in polyurethane resin technology within the flexible packaging industry, polyurethane inks, with their superior printing effects, high printing efficiency, and wide temperature adaptability, have secured a dominant position in the domestic plastic flexible packaging printing market. Furthermore, driven by environmental awareness and increased work efficiency, solvent-free polyurethane adhesive lamination is gradually replacing dry lamination as the mainstream lamination method.

[0003] While solvent-free polyurethane adhesives are environmentally friendly, their low working viscosity requirements result in smaller molecular weights, and their molecular structure is similar to that of polyurethane ink resins. This leads to ink melting issues during lamination, such as localized ink dissolution by the adhesive, causing color loss and becoming a major challenge and pain point in the industry. Therefore, there is an urgent need to develop a polyurethane ink resin with better resistance to solvent-free adhesives to improve the pigment dispersibility, hiding power, and adhesion to substrates of the ink. Summary of the Invention

[0004] The main objective of this invention is to provide a polyurethane ink resin that exhibits good resistance to solvent-free adhesives, thereby improving the pigment dispersibility, hiding power, and adhesion to the substrate of the ink.

[0005] The present invention also provides a method for preparing polyurethane ink resin, which can prepare the above-mentioned polyurethane ink resin, and the process is simple and the cost is low.

[0006] The present invention also provides an ink comprising the above-mentioned polyurethane ink resin, thereby the ink having good pigment dispersibility, hiding power, and strong substrate adhesion.

[0007] In a first aspect, the present invention provides a polyurethane ink resin, which is prepared by reacting raw materials comprising the following components in parts by weight: 18 to 34 parts polyester polyol, 2 to 8 parts isocyanate, 0.3 to 6 parts amine chain extender, and 0.05 to 5 parts end-capping agent.

[0008] The polyester polyol is formed by the condensation polymerization of diol and diacid; the diol includes dimerol.

[0009] The polyurethane ink resin described above, wherein the dimerol includes Pripol 2030 and / or Pripol 2033.

[0010] The polyurethane ink resin described above, wherein the diol further includes small molecule diols;

[0011] Preferably, the mass ratio of the dimerol to the small molecule diol is (0.2~8):1; more preferably, it is (0.3~3):1.

[0012] In the polyurethane ink resin described above, the functionality of the polyester polyol is 2 to 3, preferably 2;

[0013] The number average molecular weight of the polyester polyol is 1000~6000, preferably 1000~4000.

[0014] The polyurethane ink resin described above includes a tertiary amine with a primary or secondary amine group at one end and a tertiary amine group at the other end.

[0015] The polyurethane ink resin described above includes, as described above, N,N-dimethylethylenediamine, N,N,N'-trimethylethylenediamine, N,N-diethylethylenediamine, N,N,N'-triethylethylenediamine, N,N-dimethyl-N'-ethylethylenediamine, N,N-diethyl-N'-methylethylenediamine, N,N-di-n-propylethylenediamine, N,N-diisopropylethylenediamine, N,N-dibutylethylenediamine, N,N-diisobutylethylenediamine, N,N-dimethyl-1,3-propanediamine, N,N-diethyl-1,3-propanediamine, N,N-dipropyl-1,3-propanediamine, N,N-diisopropylpropylenediamine, N,N-dibutyl-1,3-propanediamine, N,N,N'-trimethyl-1,3-propanediamine, N,N,2, At least one of 2-tetramethyl-1,3-propanediamine, N,N-dimethyl-1,4-butanediamine, N-(3-amino-1-methylpropyl)-N,N-dimethylamine, (3-amino-2-methylpropyl)-dimethylamine, N,N,3-trimethyl-1,3-butanediamine, N,N-diethylbutane-1,4-diamine, N,N-dimethylpentane-1,5-diamine, N,N-diethylpentane-1,4-diamine, 3,3'-iminobis(N,N-dimethylpropylamine), and N,N-diisopropyl-1,5-pentanediamine; preferably including at least one of N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dimethyl-1,3-propanediamine, and N,N-diethyl-1,3-propanediamine.

[0016] The polyurethane ink resin described above, wherein the small molecule diol comprises at least one of ethylene glycol, 1,2-propanediol, 1,3-propanediol, methylpropanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexyldiol, dihydroxydiphenyl sulfone, 2,2-di(4-hydroxyphenyl)propane, and 4,4'-dihydroxydiphenylmethane; preferably, it comprises at least one of methylpropanediol, 1,4-butanediol, neopentyl glycol, and 3-methyl-1,5-pentanediol.

[0017] And / or, the dicarboxylic acid includes at least one of sebacic acid, adipic acid, azelaic acid, terephthalic acid, isophthalic acid, and phthalic acid; preferably, it includes at least one of sebacic acid, adipic acid, and azelaic acid; more preferably, it includes adipic acid.

[0018] The polyurethane ink resin described above, wherein the isocyanate comprises at least one selected from 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, it comprises at least one selected from isophorone diisocyanate (IPDI) and dicyclohexylmethane diisocyanate (HMDI).

[0019] And / or, the amine chain extender includes at least one of isophorone diamine, ethylenediamine, propylenediamine, 1,4-butanediamine, neopentyldiamine, 1,6-hexanediamine, octyldiamine, decanediamine, dodecylamine, dicyclohexylmethanediamine, and 1,4-cyclohexenediamine; preferably, it includes at least one of isophorone diamine and ethylenediamine.

[0020] Secondly, the present invention provides a method for preparing the polyurethane ink resin as described above, comprising the following steps:

[0021] 1) The first system, including polyester polyol, isocyanate, catalyst and first solvent, is reacted at 60℃~120℃ under an inert atmosphere for 3h~5h, and then cooled to below 70℃. The second solvent is added to the cooled first system to obtain a prepolymer solution.

[0022] 2) The prepolymer solution is added to a second system comprising an amine chain extender, a capping agent, and a third solvent within 0.5 h to 2 h to obtain the polyurethane ink resin.

[0023] Thirdly, 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 described above.

[0024] The polyurethane ink resin provided by this invention includes a diol used to prepare the polyester polyol. The diol is a macromolecule and usually contains non-polar segments, which can change the molecular polarity of the polyurethane ink resin, making its polarity difference with that of solvent-free adhesive greater, reducing the structural similarity between the polyurethane ink resin and the solvent-free adhesive, thereby improving the ink resin's resistance to solvent-free adhesive, and further improving the pigment dispersibility, hiding power, and adhesion to the substrate of the ink. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0026] In the modern packaging and printing industry, solvent-free polyurethane adhesives are widely used due to their environmentally friendly properties and excellent bonding performance. However, because solvent-free adhesives need to meet the requirement of low working viscosity, their molecular weight is usually small. This low molecular weight characteristic makes them prone to ink dissolution when laminated with polyurethane ink resins. This ink dissolution phenomenon causes the printed pattern to fade and become blurry, seriously affecting the appearance quality and market competitiveness of the product.

[0027] Traditional polyurethane ink resins, due to their molecular structure being similar to solvent-free adhesives, are difficult to effectively resist the dissolving effect of adhesives. Therefore, improving the solvent resistance of ink resins has become a pressing technical challenge for the industry.

[0028] To address these issues, developing a novel polyurethane ink resin is crucial. This resin not only needs to be chemically distinct from solvent-free adhesives to improve solvent resistance, but also needs to meet the printing industry's multiple performance requirements regarding color and abrasion resistance.

[0029] Based on this, in a first aspect, the present invention provides a polyurethane ink resin, which is prepared by reacting raw materials comprising the following components in parts by weight: 18 to 34 parts polyester polyol, 2 to 8 parts isocyanate, 0.3 to 6 parts amine chain extender, and 0.05 to 5 parts end-capping agent; the polyester polyol is formed by polycondensation of diol and diacid; the diol includes dimerol.

[0030] For example, the number of parts of polyester polyol can be 18 parts, 19 parts, 20 parts, 22 parts, 25 parts, 27 parts, 30 parts, 32 parts, 34 parts, or any two of these; the number of parts of isocyanate can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, or any two of these; the number of parts of amine chain extender can be 0.3 parts, 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, or any two of these; and the number of parts of end-capping agent can be 0.05 parts, 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, or any two of these.

[0031] The polyurethane ink resin provided by this invention includes a diol used to prepare the polyester polyol, which can improve the polyurethane ink resin's resistance to solvent-free adhesives, thereby improving the ink's pigment dispersibility, hiding power, and adhesion to the substrate.

[0032] Specifically, in the polyurethane ink resin provided by the present invention, the polyester polyol is formed by the condensation polymerization of diol and diacid. The diol includes dimerol, which is a macromolecule and usually contains non-polar segments. It can change the molecular polarity of the polyurethane ink resin, making its polarity difference with that of solvent-free adhesive greater, reducing the structural similarity between the polyurethane ink resin and the solvent-free adhesive, thereby improving the ink resistance of the polyurethane ink resin to solvent-free adhesive, and further improving the pigment dispersion, hiding power and adhesion of the ink to the substrate.

[0033] Furthermore, in the polyurethane ink resin provided by this invention, the isocyanate groups (-NCO) in the raw material isocyanate can undergo an addition reaction with the hydroxyl groups (-OH) in the polyol to form a polyurethane chain. This reaction is the basis for the formation of polyurethane. Through cross-linking reaction, a polymer network with a certain molecular weight and structure is formed, which enhances the mechanical strength and chemical resistance of the polyurethane ink resin.

[0034] Furthermore, in the polyurethane ink resin provided by this 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 crosslinking density of the polyurethane ink resin, enhancing its mechanical strength and chemical resistance.

[0035] Furthermore, in the polyurethane ink resin provided by this invention, the raw material end-capping agent is used to terminate the polyurethane synthesis reaction and prevent excessive crosslinking or chain growth. End-capping allows for precise control of the polymer's molecular weight and structure, thereby obtaining the desired physical and chemical properties.

[0036] The polyurethane ink resin provided by this invention includes a diol used to prepare the polyester polyol. The diol is a macromolecule and usually contains non-polar segments, which can change the molecular polarity of the polyurethane ink resin, making its polarity difference with that of solvent-free adhesive greater, reducing the structural similarity between the polyurethane ink resin and the solvent-free adhesive, thereby improving the ink resin's resistance to solvent-free adhesive, and further improving the pigment dispersibility, hiding power, and adhesion to the substrate of the ink.

[0037] In this invention, the dimerol includes a main chain and alkane side chains attached to the main chain.

[0038] In some embodiments of the present invention, the dimerol includes Pripol 2030 and / or Pripol 2033.

[0039] The dimerols of the present invention include Pripol 2030 and / or Pripol 2033, which have a six-membered ring structure and alkane side chains. That is, by introducing non-polar segments and alkane side chains, the molecular structure can be changed, thereby improving the ink-dissolving properties of polyurethane ink resins against solvent-free adhesives. On the other hand, it can improve the affinity for pigments and non-polar printing substrates, that is, improve the ink's dispersibility for pigments, anti-blocking properties, hiding properties, and adhesion to the substrate.

[0040] In some embodiments of the present invention, the diol further includes a small molecule diol; preferably, the mass ratio of the diol and the small molecule diol is (0.2~8):1, for example, it can be a range of 0.2:1, 0.3:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1 or any two of them; more preferably, it is (0.3~3):1.

[0041] In this invention, the diols also include small-molecule diols, i.e., diol compounds. Diols typically have high molecular weights and complex structures, while small-molecule diols are simpler and have short chains. By adjusting the mass ratio of diols and small-molecule diols within the aforementioned range, the molecular weight and chain structure of the polyester polyol can be precisely controlled, thereby affecting the physical properties of the polyurethane ink resin. Furthermore, an appropriate proportion of diols can increase the crosslinking density and chemical stability of the polyurethane ink resin, thereby improving its resistance to solvent-free adhesives. Small-molecule diols, on the other hand, contribute to improving the uniformity and stability of the ink resin.

[0042] In some embodiments of the present invention, the functionality of the polyester polyol is 2 to 3, preferably 2.

[0043] The number average molecular weight of the polyester polyol is 1000 to 6000, for example, it can be a range of 1000, 2000, 3000, 4000, 5000, 6000 or any two of them; preferably it is 1000 to 4000.

[0044] In this invention, the functionality and number-average molecular weight of the polyester polyol are within the aforementioned range, which can adjust the hardness, flexibility, and elasticity of the polyurethane ink resin. This helps control the crosslinking density of the polyurethane ink resin; a moderate crosslinking density can improve the mechanical properties of the polyurethane ink resin, such as tensile and tear resistance. It can also enhance the chemical resistance of the polyurethane ink resin, making it stable when in contact with solvents and other chemicals. Furthermore, it can improve the flowability and pigment dispersibility of the polyurethane ink resin, ensuring color uniformity and opacity of the ink. It also helps form a uniform polymer network, improving the ink's adhesion to the substrate and ensuring the durability and quality of the printed matter.

[0045] In some embodiments of the present invention, the capping agent comprises a tertiary amine having a primary or secondary amine group at one end and a tertiary amine group at the other end. Furthermore, the capping agents include N,N-dimethylethylenediamine, N,N,N'-trimethylethylenediamine, N,N-diethylethylenediamine, N,N,N'-triethylethylenediamine, N,N-dimethyl-N'-ethylethylenediamine, N,N-diethyl-N'-methylethylenediamine, N,N-di-n-propylethylenediamine, N,N-diisopropylethylenediamine, N,N-dibutylethylenediamine, N,N-diisobutylethylenediamine, N,N-dimethyl-1,3-propanediamine, N,N-diethyl-1,3-propanediamine, N,N-dipropyl-1,3-propanediamine, N,N-diisopropylpropanediamine, N,N-dibutyl-1,3-propanediamine, N,N,N'-trimethyl-1,3-propanediamine, and N,N,2,2-tetramethylethylenediamine. At least one of 1,3-propanediamine, N,N-dimethyl-1,4-butanediamine, N-(3-amino-1-methylpropyl)-N,N-dimethylamine, (3-amino-2-methylpropyl)-dimethylamine, N,N,3-trimethyl-1,3-butanediamine, N,N-diethylbutane-1,4-diamine, N,N-dimethylpentane-1,5-diamine, N,N-diethylpentane-1,4-diamine, 3,3'-iminobis(N,N-dimethylpropylamine), and N,N-diisopropyl-1,5-pentanediamine; preferably including at least one of N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dimethyl-1,3-propanediamine, and N,N-diethyl-1,3-propanediamine.

[0046] In this invention, the end-capping agent comprises a tertiary amine with a primary or secondary amine group at one end and a tertiary amine group at the other end. By introducing a functional tertiary amine into the end of the polyurethane ink resin molecule, the polarity of the polyurethane ink resin can be altered, improving its resistance to solvent-free adhesives. This, in turn, enhances the dispersibility, anti-blocking properties, hiding power, and adhesion to the substrate of the ink, reducing the risk of pattern fading during printing. Furthermore, the use of the end-capping agent can regulate the rheological properties of the polyurethane ink resin, giving it better flowability and stability during processing and application.

[0047] In some embodiments of the present invention, the small molecule diol includes at least one of ethylene glycol, 1,2-propanediol, 1,3-propanediol, methylpropanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexyldiol, dihydroxydiphenyl sulfone, 2,2-di(4-hydroxyphenyl)propane, and 4,4'-dihydroxydiphenylmethane; preferably, it includes at least one of methylpropanediol, 1,4-butanediol, neopentyl glycol, and 3-methyl-1,5-pentanediol.

[0048] In some embodiments, the dicarboxylic acid includes at least one of sebacic acid, adipic acid, azelaic acid, terephthalic acid, isophthalic acid, and phthalic acid; preferably, it includes at least one of sebacic acid, adipic acid, and azelaic acid; more preferably, it includes adipic acid.

[0049] In this invention, the aforementioned small molecule diols can adjust the flexibility and hardness of polyester polyols, thereby affecting the viscosity and rheological properties of polyurethane ink resins, making them easier to process and apply.

[0050] In this invention, the aforementioned dicarboxylic acid can enhance the mechanical properties of polyurethane ink resins, such as tensile and tear resistance. It also affects the polarity and surface energy of the polyurethane ink resins, thereby improving the dispersibility of pigments in the ink and their adhesion to the substrate.

[0051] In some embodiments of the present invention, the isocyanate includes at least one selected from 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, it includes at least any one selected from isophorone diisocyanate (IPDI) and dicyclohexylmethane diisocyanate (HMDI).

[0052] In some embodiments, the amine chain extender includes at least one of isophorone diamine, ethylenediamine, propylenediamine, 1,4-butanediamine, neopentyldiamine, 1,6-hexanediamine, octyldiamine, decanediamine, dodecylamine, dicyclohexylmethanediamine, and 1,4-cyclohexenediamine; preferably, it includes at least one of isophorone diamine and ethylenediamine.

[0053] The isocyanate and amine chain extender described above in this invention can further enhance the mechanical properties and chemical resistance of polyurethane ink resin.

[0054] Secondly, the present invention provides a method for preparing the polyurethane ink resin as described above, comprising the following steps:

[0055] 1) A first system comprising polyester polyol, isocyanate, catalyst, and first solvent is reacted at 60℃~120℃, for example, 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, etc., under an inert atmosphere for 3h~5h, for example, 3h, 3.5h, 4h, 4.5h, 5h, etc., and then cooled to below 70℃, for example, 10℃, 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, etc., and a second solvent is added to the cooled first system to obtain a prepolymer solution;

[0056] 2) The prepolymer solution is added to a second system including an amine chain extender, a capping agent, and a third solvent within 0.5h to 2h, for example, 0.5h, 0.7h, 0.9h, 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, etc., to obtain polyurethane ink resin.

[0057] In the preparation method of polyurethane ink resin of the present invention, the first solvent and the second solvent can be the same or different, the second solvent and the third solvent can be the same or different, and the first solvent and the third solvent can be the same or different.

[0058] In step 1), the first solvent includes esters and / or alcohols, such as secondary alcohols and tertiary alcohols; preferably, it includes at least one of ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, and isopropanol; more preferably, it includes at least one of ethyl acetate, n-propyl acetate, and isopropanol. The second solvent includes esters and / or alcohols, such as secondary alcohols and tertiary alcohols; preferably, it includes at least one of ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, and isopropanol; more preferably, it includes at least one of ethyl acetate, n-propyl acetate, and isopropanol. The polyester polyol can be prepared according to methods known in the art, for example, by adding a dimerol, a small molecule diol, a diacid, and tetrabutyl titanate (as a catalyst) to a reactor, purging with nitrogen, and stirring the reaction at 150°C to 260°C for 24 to 36 hours to obtain the polyester polyol.

[0059] A first system comprising polyester polyol, isocyanate, catalyst, and a first solvent is placed in a container, and an inert gas, such as nitrogen, is introduced. The reaction is carried out at 60°C to 120°C for 3 to 5 hours, then cooled to below 70°C. A second solvent is then added to the cooled first system. The addition of the second solvent reduces the viscosity of the first system, resulting in a prepolymer solution. The catalyst can be a commonly used catalyst in the art, including but not limited to at least one of dimethyltin diacetate, dibutyltin dibutyrate, di(2-ethylhexanoate), dibutyltin dilaurate, dioctyltin dilaurate, zinc dioctanoate (II), zirconium acetylacetonate, zirconium 2,2,6,6-tetramethyl-3,5-heptanedione, bismuth neodecanoate, and bismuth 2-ethylhexanoate; preferably dibutyltin dilaurate, bismuth neodecanoate, and bismuth 2-ethylhexanoate, more preferably bismuth neodecanoate. The amount of catalyst added is the conventional amount used in the art.

[0060] In step 2), the third solvent includes esters and / or alcohols, such as secondary alcohols and tertiary alcohols; preferably, it includes at least one of ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, and isopropanol; more preferably, it includes at least one of ethyl acetate, n-propyl acetate, and isopropanol. The amine chain extender, end-capping agent, and third solvent are stirred until homogeneous to obtain a second system. Then, under stirring at room temperature, the prepolymer solution is added dropwise to the second system over 0.5 h to 2 h, thereby controlling the polymerization rate of the polyurethane ink resin and obtaining the polyurethane ink resin.

[0061] The method for preparing polyurethane ink resin provided by the present invention can prepare the above-mentioned polyurethane ink resin. The polyurethane ink resin has good resistance to solvent-free adhesives, thereby improving the pigment dispersibility, hiding power and adhesion to the substrate of the ink.

[0062] Thirdly, 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 described above.

[0063] The ink provided by this invention can be a solvent-based gravure composite ink, including the aforementioned polyurethane ink resin. Therefore, the ink has good pigment dispersibility, opacity, and strong substrate adhesion.

[0064] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0065] The raw materials used in the examples and comparative examples are as follows:

[0066] Isophorone diisocyanate, IPDI, Wanhua Chemical;

[0067] Toluene diisocyanate, TDI-80, Wanhua Chemical;

[0068] Dicyclohexylmethane diisocyanate, HMDI, Wanhua Chemical;

[0069] Dimerol, Pripol 2030, Pripol 2033, Cargill;

[0070] Methylpropanediol (MPO), from Dalian, Taiwan, China;

[0071] 1,4-Butanediol, BDO, Wanhua Chemical;

[0072] Neopentyl glycol, NPG, Wanhua Chemical;

[0073] Oxalic acid, AA, Huafeng Chemical;

[0074] Tetrabutyl titanate, Aladdin;

[0075] Polyester polyol 2000PM was obtained by reacting adipic acid and methyl propylene glycol, with a number average molecular weight of 2000, produced by Asahikawa Chemicals.

[0076] BICAT8118, an organobismuth catalyst, is produced by a leading American chemical company.

[0077] Isophorone diamine, IPDA, Wanhua Chemical;

[0078] Ethylenediamine, EDA, Inokai;

[0079] N,N-Dimethylethylenediamine, DMEDA, Inokai;

[0080] N,N-Diethylethylenediamine, DEEDA, Inokai;

[0081] N,N-Dimethyl-1,3-propanediamine, DMPDA, Inokai;

[0082] N,N-Diethyl-1,3-propanediamine, DEPDA, Inokai;

[0083] N,N-Dibutylethylenediamine, DBEDA, Inokai;

[0084] Di-n-butylamine, DBA, Inokai;

[0085] Ethyl acetate, EA, Jiangmen Qianxin Chemical Co., Ltd., China;

[0086] Isopropyl alcohol, IPA, Jinzhou Petrochemical in China.

[0087] The preparation method of polyester polyol B1 includes the following steps: 528.4g of Pripol 2030, 176.1g of MPO (the mass ratio of Pripol 2030 to MPO is 3:1), 392.1g of AA and 0.05g of tetrabutyl titanate catalyst are added to a flask, nitrogen gas is introduced, the mixture is stirred evenly, heated to 230℃, and reacted for 24h. After dehydration, polyester polyol B1 is obtained, with a number average molecular weight of approximately 4000, a hydroxyl value of 28mgKOH / g, an acid value of 0.38mgKOH / g, and a functionality of 2.

[0088] The preparation method of polyester polyol B2 includes the following steps: 307.9g of Pripol 2030, 307.9g of BDO (the mass ratio of Pripol 2030 to BDO is 1:1), 509.8g of AA and 0.05g of tetrabutyl titanate catalyst are added to a flask, nitrogen gas is introduced, the mixture is stirred evenly, heated to 230℃, and reacted for 32h. After dehydration, polyester polyol B2 is obtained, with a number average molecular weight of approximately 2000, a hydroxyl value of 56mgKOH / g, an acid value of 0.25mgKOH / g, and a functionality of 2.

[0089] The preparation method of polyester polyol B3 includes the following steps: 150.5g of Pripol2033, 451.4g of NPG (the mass ratio of Pripol2033 to NPG is 0.3:1), 528.4g of AA and 0.05g of tetrabutyl titanate catalyst are added to a flask, nitrogen gas is introduced, the mixture is stirred evenly, heated to 230℃, and reacted for 36h. After dehydration, polyester polyol B3 is obtained, with a number average molecular weight of approximately 1000, a hydroxyl value of 112mgKOH / g, an acid value of 0.13mgKOH / g, and a functionality of 2.

[0090] The preparation method of polyester polyol B4 includes the following steps: 96.6g of Pripol 2033, 482.9g of MPO (the mass ratio of Pripol 2033 to MPO is 0.2:1), 558.1g of AA and 0.05g of tetrabutyl titanate catalyst are added to a flask, nitrogen gas is introduced, the mixture is stirred evenly, heated to 230℃, and reacted for 36h. After dehydration, polyester polyol B4 is obtained, with a number average molecular weight of approximately 1000, a hydroxyl value of 111mgKOH / g, an acid value of 0.16mgKOH / g, and a functionality of 2.

[0091] The preparation method of polyester polyol B5 includes the following steps: 703.3g of Pripol2033, 87.9g of MPO (the mass ratio of Pripol2033 to MPO is 8:1), 277.1g of AA and 0.05g of tetrabutyl titanate catalyst are added to a flask, nitrogen gas is introduced, the mixture is stirred evenly, heated to 230℃, and reacted for 36h. After dehydration, polyester polyol B5 is obtained, with a number average molecular weight of approximately 4000, a hydroxyl value of 28mgKOH / g, an acid value of 0.24mgKOH / g, and a functionality of 2.

[0092] Example 1

[0093] The preparation method of the polyurethane ink resin in this embodiment includes the following steps:

[0094] 100g of polyester polyol B1, 11.46g of IPDI, 0.03g of Bicat8118 and 30g of EA were put into a flask, nitrogen gas was introduced, and the reaction was carried out at 75℃ for 5h. After cooling to below 70℃, 50g of EA was added to obtain a prepolymer solution.

[0095] In another flask, 4.07 g of IPDA, 0.56 g of N,N-dimethylethylenediamine, 123.1 g of EA and 67.7 g of IPA were added and stirred until homogeneous to obtain a chain extender solution, i.e., the second system. Then, under stirring at room temperature, the above prepolymer solution was added dropwise to the second system over 0.5 h to obtain polyurethane ink resin Eg1.

[0096] Example 2

[0097] The preparation method of the polyurethane ink resin in this embodiment includes the following steps:

[0098] 100g of polyester polyol B2, 15.71g of IPDI, 0.03g of Bicat8118 and 30g of EA were put into a flask, nitrogen gas was introduced, and the reaction was carried out at 75℃ for 4h. After cooling to below 70℃, 50g of EA was added to obtain a prepolymer solution.

[0099] In another flask, 3.17 g of IPDA, 0.44 g of N,N-dimethylethylenediamine, 128.8 g of EA and 69.6 g of IPA were added and stirred until homogeneous to obtain a chain extender solution, i.e., the second system. Then, under stirring at room temperature, the above prepolymer solution was added dropwise to the second system over 0.5 h to obtain polyurethane ink resin Eg2.

[0100] Example 3

[0101] The preparation method of the polyurethane ink resin in this embodiment includes the following steps:

[0102] 100g of polyester polyol B3, 26.24g of IPDI, 0.03g of Bicat8118 and 30g of EA were put into a flask, nitrogen gas was introduced, and the reaction was carried out at 75℃ for 3h. After cooling to below 70℃, 50g of EA was added to obtain a prepolymer solution.

[0103] In another flask, 2.76 g of IPDA, 0.38 g of N,N-dimethylethylenediamine, 146.4 g of EA and 75.5 g of IPA were added and stirred until homogeneous to obtain a chain extender solution, i.e., the second system. Then, under stirring at room temperature, the above prepolymer solution was added dropwise to the second system over 0.5 h to obtain polyurethane ink resin Eg3.

[0104] Example 4

[0105] 100g of polyester polyol B1, 11.46g of IPDI, 0.03g of Bicat8118 and 30g of EA were put into a flask, nitrogen gas was introduced, and the reaction was carried out at 75℃ for 5h. After cooling to below 70℃, 50g of EA was added to obtain a prepolymer solution.

[0106] In another flask, 4.29 g of IPDA, 0.62 g of N,N-diethylethylenediamine, 123.6 g of EA and 67.9 g of IPA were added and stirred until homogeneous to obtain a chain extender solution, i.e., the second system. Then, under stirring at room temperature, the above prepolymer solution was added dropwise to the second system over 0.5 h to obtain polyurethane ink resin Eg4.

[0107] Example 5

[0108] The preparation method of the polyurethane ink resin in this embodiment includes the following steps:

[0109] 100g of polyester polyol B2, 15.71g of IPDI, 0.03g of Bicat8118 and 30g of EA were put into a flask, nitrogen gas was introduced, and the reaction was carried out at 75℃ for 4h. After cooling to below 70℃, 50g of EA was added to obtain a prepolymer solution.

[0110] In another flask, 3.1 g of IPDA, 0.59 g of N,N-dimethyl-1,3-propanediamine, 128.9 g of EA and 69.6 g of IPA were added and stirred until homogeneous to obtain a chain extender solution, i.e., the second system. Then, under stirring at room temperature, the above prepolymer solution was added dropwise to the second system over 0.5 h to obtain polyurethane ink resin Eg5.

[0111] Example 6

[0112] The preparation method of the polyurethane ink resin in this embodiment includes the following steps:

[0113] 100g of polyester polyol B3, 26.24g of IPDI, 0.03g of Bicat8118 and 30g of EA were put into a flask, nitrogen gas was introduced, and the reaction was carried out at 75℃ for 3h. After cooling to below 70℃, 50g of EA was added to obtain a prepolymer solution.

[0114] In another flask, 2.70 g of IPDA, 0.66 g of N,N-diethyl-1,3-propanediamine, 146.8 g of EA and 75.6 g of IPA were added and stirred until homogeneous to obtain a chain extender solution, i.e., the second system. Then, under stirring at room temperature, the above prepolymer solution was added dropwise to the second system over 0.5 h to obtain polyurethane ink resin Eg6.

[0115] Example 7

[0116] The preparation method of the polyurethane ink resin in this embodiment includes the following steps:

[0117] 100g of polyester polyol B1, 13.64g of HMDI, 0.03g of Bicat8118 and 30g of EA were put into a flask, nitrogen gas was introduced, and the reaction was carried out at 75℃ for 5h. After cooling to below 70℃, 50g of EA was added to obtain a prepolymer solution.

[0118] In another flask, 4.38 g of IPDA, 0.48 g of N,N-dimethylethylenediamine, 127.4 g of EA and 69.1 g of IPA were added and stirred until homogeneous to obtain a chain extender solution, i.e., the second system. Then, under stirring at room temperature, the above prepolymer solution was added dropwise to the second system over 0.5 h to obtain polyurethane ink resin Eg7.

[0119] Example 8

[0120] The preparation method of the polyurethane ink resin in this embodiment includes the following steps:

[0121] 100g of polyester polyol B2, 12.20g of TDI-80, 0.03g of Bicat8118 and 30g of EA were put into a flask, nitrogen gas was introduced, and the reaction was carried out at 75℃ for 3h. After cooling to below 70℃, 50g of EA was added to obtain a prepolymer solution.

[0122] In another flask, 3.07 g of IPDA, 0.56 g of N,N-diethylethylenediamine, 122.7 g of EA and 67.6 g of IPA were added and stirred until homogeneous to obtain a chain extender solution, i.e., the second system. Then, under stirring at room temperature, the above prepolymer solution was added dropwise to the second system over 0.5 h to obtain polyurethane ink resin Eg8.

[0123] Example 9

[0124] The preparation method of the polyurethane ink resin in this embodiment includes the following steps:

[0125] 100g of polyester polyol B2, 15.71g of IPDI, 0.03g of Bicat8118 and 30g of EA were put into a flask, nitrogen gas was introduced, and the reaction was carried out at 75℃ for 4h. After cooling to below 70℃, 50g of EA was added to obtain a prepolymer solution.

[0126] In another flask, 1.18 g of EDA, 0.71 g of N,N-dibutylethylenediamine, 125.8 g of EA and 68.6 g of IPA were added and stirred until homogeneous to obtain a chain extender solution, i.e., the second system. Then, under stirring at room temperature, the above prepolymer solution was added dropwise to the second system over 0.5 h to obtain polyurethane ink resin Eg9.

[0127] Example 10

[0128] The preparation method of the polyurethane ink resin in this embodiment includes the following steps:

[0129] 100g of polyester polyol B3, 26.24g of IPDI, 0.03g of Bicat8118 and 30g of EA were put into a flask, nitrogen gas was introduced, and the reaction was carried out at 75℃ for 3h. After cooling to below 70℃, 50g of EA was added to obtain a prepolymer solution.

[0130] In another flask, 2.76 g of IPDA, 0.56 g of di-n-butylamine, 146.7 g of EA and 75.6 g of IPA were added and stirred until homogeneous to obtain a chain extender solution, i.e., the second system. Then, under stirring at room temperature, the above prepolymer solution was added dropwise to the second system over 0.5 h to obtain polyurethane ink resin Eg10.

[0131] Example 11

[0132] The preparation method of the polyurethane ink resin in this embodiment includes the following steps:

[0133] 100g of polyester polyol B4, 26.24g of IPDI, 0.03g of Bicat8118 and 30g of EA were put into a flask, nitrogen gas was introduced, and the reaction was carried out at 75℃ for 3h. After cooling to below 70℃, 50g of EA was added to obtain a prepolymer solution.

[0134] In another flask, 2.76 g of IPDA, 0.38 g of N,N-dimethylethylenediamine, 146.4 g of EA and 75.5 g of IPA were added and stirred until homogeneous to obtain a chain extender solution, i.e., the second system. Then, under stirring at room temperature, the above prepolymer solution was added dropwise to the second system over 0.5 h to obtain polyurethane ink resin Eg11.

[0135] Example 12

[0136] The preparation method of the polyurethane ink resin in this embodiment includes the following steps:

[0137] 100g of polyester polyol B5, 11.46g of IPDI, 0.03g of Bicat8118 and 30g of EA were put into a flask, nitrogen gas was introduced, and the reaction was carried out at 75℃ for 5h. After cooling to below 70℃, 50g of EA was added to obtain a prepolymer solution.

[0138] In another flask, 4.07 g of IPDA, 0.56 g of N,N-dimethylethylenediamine, 123.1 g of EA and 67.7 g of IPA were added and stirred until homogeneous to obtain a chain extender solution, i.e., the second system. Then, under stirring at room temperature, the above prepolymer solution was added dropwise to the second system over 0.5 h to obtain polyurethane ink resin Eg12.

[0139] Comparative Example 1

[0140] The preparation method of the polyurethane ink resin in this comparative example includes the following steps:

[0141] 100g of polyester polyol 2000PM, 15.71g of IPDI, 0.03g of Bicat8118 and 30g of EA were put into a flask, nitrogen gas was introduced, and the reaction was carried out at 75℃ for 4h. After cooling to below 70℃, 50g of EA was added to obtain a prepolymer solution.

[0142] In another flask, 3.17 g of IPDA, 0.44 g of N,N-dimethylethylenediamine, 128.8 g of EA and 69.6 g of IPA were added and stirred until homogeneous to obtain a chain extender solution, i.e., the second system. Then, under stirring at room temperature, the above prepolymer solution was added dropwise to the second system over 0.5 h to obtain polyurethane ink resin C1.

[0143] Table 1. Formulations of polyurethane ink resins in Examples 1-12 and Comparative Example 1

[0144]

[0145] The polyurethane ink resins obtained in Examples 1-12 and Comparative Example 1 were prepared into inks according to the formulation in Table 2. Each raw material was placed into a 500mL iron can, and then an equal mass of 1mm diameter glass microspheres were added. After sealing, the can was ground for 3-4 hours using a coating rapid mixer to obtain polyurethane ink for gravure printing.

[0146] Table 2 Polyurethane Gravure Ink Formulation

[0147]

[0148] The prepared polyurethane ink for gravure printing was tested according to the following method:

[0149] (1) Ink gloss test method

[0150] Apply ink to a polyethylene terephthalate (PET) film using a wire rod, so that the dry film thickness of the ink layer is 2μm~3μm; after drying the ink film with a hair dryer, observe the state of the coated surface and evaluate the ink gloss.

[0151] The evaluation criteria are as follows: ◎ indicates good gloss; ○ indicates average gloss; × indicates poor gloss.

[0152] (2) Ink adhesion test method

[0153] Refer to GB / T13217.7-2009.

[0154] The plastic films are polyethylene terephthalate (PET) film with corona treatment on the surface and biaxially oriented polypropylene (BOPP) film.

[0155] The evaluation criteria are as follows: ◎ indicates ink residue of 90% or more; ○ indicates ink residue of 60-90%; × indicates ink residue of less than 50%.

[0156] (3) Ink redissolution test method

[0157] The ink was sampled using a KPP gravure ink proofing machine (manufactured by RK Company, UK, 150 lines / inch for printing plates). After the ink on the printing plate dried, about 1 to 2 grams of test solvent was quickly dropped onto the ink layer of the printing plate using a dropper, and then the time was set. After 30 seconds, the solvent was blown away with a hair dryer to expose the solvent-covered ink layer and the printing plate, and the dissolution of the ink layer was observed.

[0158] Evaluation criteria for the resolubility of ink film: ◎ indicates that the ink layer is significantly 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 significantly undissolved.

[0159] (4) Solvent-free adhesive leveling test

[0160] Use a KPP gravure ink proofing machine to make an ink sample. After the ink on the printing plate dries, use the same KPP gravure ink proofing machine to apply solvent-free composite adhesive. Observe the state of the coated surface. The higher the gloss, the better the leveling properties of the adhesive.

[0161] The evaluation criteria are as follows: ◎ indicates good leveling; ○ indicates average leveling; × indicates poor leveling.

[0162] (5) Solvent-free adhesive water-soluble ink test

[0163] The ink was sampled using a KPP gravure ink sampler. After the ink on the printing plate dried, solvent-free composite adhesive was applied using the same KPP gravure ink sampler. Then it was laminated with a PET aluminized film. The state of the ink layer was observed after 30 minutes.

[0164] The evaluation criteria are as follows: ◎ indicates good solvent-resistant ink; ○ indicates average solvent-resistant ink; × indicates poor solvent-resistant ink.

[0165] (6) The standard for testing ink viscosity is GB / T13217.4-91.

[0166] (7) The standard for ink fineness testing is GB / T13217.3-91.

[0167] (8) The standard for ink hiding power test is GB / T13217.6-2008, wherein the standard sample for hiding power test is the ink prepared by the formulation of Example 1.

[0168] The test results are shown in Table 3.

[0169] Table 3 Test Results of White Ink for Polyurethane Gravure Ink

[0170]

[0171] As shown in Table 3, the diol used to prepare the polyester polyol in the polyurethane ink resin provided by this invention includes a diol. The diol is a macromolecule and usually contains non-polar segments, which can change the molecular polarity of the polyurethane ink resin, making its polarity difference with that of solvent-free adhesive greater, reducing the structural similarity between the polyurethane ink resin and the solvent-free adhesive, thereby improving the ink resistance of the polyurethane ink resin to solvent-free adhesive, improving the pigment dispersion and hiding power of the ink, and also improving the adhesion to the substrate.

[0172] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A polyurethane ink resin, characterized in that, It is prepared by reacting raw materials comprising the following components in parts by weight: 18 to 34 parts polyester polyol, 2 to 8 parts isocyanate, 0.3 to 6 parts amine chain extender, and 0.05 to 5 parts end-capping agent; The polyester polyol is formed by the condensation polymerization of diol and diacid; the diol includes dimerol and small molecule diol; The dimerols include Pripol 2030 and / or Pripol 2033; The capping agent is a tertiary amine with a primary or secondary amine group at one end and a tertiary amine group at the other end; The mass ratio of the dimerol to the small molecule diol is (0.2~8):1; The functionality of the polyester polyol is 2 to 3; The number average molecular weight of the polyester polyol is 1000~6000.

2. The polyurethane ink resin according to claim 1, characterized in that, The mass ratio of the dimerol to the small molecule diol is (0.3~3):

1.

3. The polyurethane ink resin according to claim 1, characterized in that, The functionality of the polyester polyol is 2.

4. The polyurethane ink resin according to claim 1, characterized in that, The number average molecular weight of the polyester polyol is 1000~4000.

5. The polyurethane ink resin according to any one of claims 1-4, characterized in that, The capping agent includes N,N-dimethylethylenediamine, N,N,N'-trimethylethylenediamine, N,N-diethylethylenediamine, N,N,N'-triethylethylenediamine, N,N-dimethyl-N'-ethylethylenediamine, N,N-diethyl-N'-methylethylenediamine, N,N-di-n-propylethylenediamine, N,N-diisopropylethylenediamine, N,N-dibutylethylenediamine, N,N-diisobutylethylenediamine, N,N-dimethyl-1,3-propanediamine, N,N-diethyl-1,3-propanediamine, N,N-dipropyl-1,3-propanediamine, N,N-diisopropylpropanediamine, and N,N-dibutyl-1,3-propanediamine. At least one of N,N,N'-trimethyl-1,3-propanediamine, N,N,2,2-tetramethyl-1,3-propanediamine, N,N-dimethyl-1,4-butanediamine, N-(3-amino-1-methylpropyl)-N,N-dimethylamine, (3-amino-2-methylpropyl)-dimethylamine, N,N,3-trimethyl-1,3-butanediamine, N,N-diethylbutane-1,4-diamine, N,N-dimethylpentane-1,5-diamine, N,N-diethylpentane-1,4-diamine, 3,3'-iminobis(N,N-dimethylpropylamine), and N,N-diisopropyl-1,5-pentanediamine.

6. The polyurethane ink resin according to claim 5, characterized in that, The end-capping agent includes at least one of N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dimethyl-1,3-propanediamine, and N,N-diethyl-1,3-propanediamine.

7. The polyurethane ink resin according to claim 1, characterized in that, The small molecule diols include at least one of ethylene glycol, 1,2-propanediol, 1,3-propanediol, methylpropanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexyldiol, dihydroxydiphenyl sulfone, 2,2-bis(4-hydroxyphenyl)propane, and 4,4'-dihydroxydiphenylmethane. And / or, the dicarboxylic acid includes at least one of sebacic acid, adipic acid, azelaic acid, terephthalic acid, isophthalic acid, and phthalic acid.

8. The polyurethane ink resin according to claim 7, characterized in that, The small molecule diols include at least one of methylpropanediol, 1,4-butanediol, neopentyl glycol, and 3-methyl-1,5-pentanediol.

9. The polyurethane ink resin according to claim 7, characterized in that, The dicarboxylic acid includes at least one of sebacic acid, adipic acid, and azelaic acid.

10. The polyurethane ink resin according to claim 9, characterized in that, The dicarboxylic acid includes adipic acid.

11. The polyurethane ink resin according to any one of claims 1-4, characterized in that, The isocyanate includes at least one selected from toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), 1,4-cyclohexane diisocyanate (CHDI), cyclohexane diisocyanate (HXDI), trimethyl-1,6-hexamethylene diisocyanate (TMHDI), and methylcyclohexyl diisocyanate (HTDI). And / or, the amine chain extender includes at least one of isophorone diamine, ethylenediamine, propylenediamine, 1,4-butanediamine, neopentyldiamine, 1,6-hexanediamine, octanediamine, decanediamine, dodecylamine, dicyclohexylmethanediamine, and 1,4-cyclohexenediamine.

12. The polyurethane ink resin according to claim 11, characterized in that, The isocyanate includes at least one of isophorone diisocyanate (IPDI) and dicyclohexylmethane diisocyanate (HMDI); And / or, the amine chain extender includes at least one of isophorone diamine and ethylenediamine.

13. A method for preparing the polyurethane ink resin according to any one of claims 1-12, characterized in that, Includes the following steps: 1) The first system, including polyester polyol, isocyanate, catalyst and first solvent, is reacted at 60℃~120℃ under an inert atmosphere for 3h~5h, and then cooled to below 70℃. The second solvent is added to the cooled first system to obtain a prepolymer solution. 2) The prepolymer solution is added to a second system comprising an amine chain extender, a capping agent, and a third solvent within 0.5 h to 2 h to obtain the polyurethane ink resin.

14. An ink, characterized in that, Includes the polyurethane ink resin according to any one of claims 1-12 or the polyurethane ink resin prepared according to the preparation method of claim 13.

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