Polyurethane ink resin as well as preparation method and application thereof

Abstract

The invention provides polyurethane ink resin as well as a preparation method and application thereof. The polyurethane ink resin is prepared from the following raw materials in parts by mass through reaction: 18 to 34 parts of polyester polyol, 2 to 8 parts of isocyanate, 0.3 to 6 parts of amine chain extender and 0.05 to 5 parts of end-capping reagent. The polyester polyol is formed by polycondensation of dihydric alcohol and dibasic acid; the dihydric alcohol comprises dimer alcohol. In the polyurethane ink resin provided by the invention, the dihydric alcohol for preparing the polyester polyol comprises the dihydric alcohol, and the dihydric alcohol is a macromolecule and usually contains a non-polar chain segment, so that the molecular polarity of the polyurethane ink resin can be changed, the polarity difference between the polyurethane ink resin and the solvent-free glue is increased, and the structural similarity between the polyurethane ink resin and the solvent-free glue is reduced; therefore, the ink dissolution resistance of the polyurethane ink resin to solvent-free glue can be improved, and the pigment dispersity and covering performance of the ink and the adhesive force of the ink to a base material can be further improved.

Description

Technical Field

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

[0002] With the advancement of polyurethane resin technology in the flexible packaging industry, on the one hand, polyurethane inks dominate the domestic plastic flexible packaging printing with their exquisite printing effects, high printing efficiency and wide temperature adaptability. On the other hand, based on the awareness of environmental protection and the improvement of work efficiency, polyurethane solvent-free glue lamination has gradually replaced dry lamination to become the mainstream lamination method.

[0003] Although polyurethane solvent-free glue is environmentally friendly, it is limited by the requirement of low working viscosity, has a small molecular weight, and its molecular structure is similar to polyurethane ink resin. Therefore, when compounding, it is easy to cause local ink to be dissolved by glue, causing the pattern to lose color, which has become a difficulty and pain point in the industry. Therefore, it is urgent to develop a polyurethane ink resin with good anti-solvent performance against solvent-free glue to improve the pigment dispersion, hiding performance and adhesion of the ink to the substrate. Summary of the invention

[0004] The main purpose of the present invention is to provide a polyurethane ink resin, which has good anti-ink performance to solvent-free glue, thereby improving the pigment dispersibility, hiding performance and adhesion to the substrate of the ink.

[0005] The present invention also provides a method for preparing the polyurethane ink resin, which can be used to prepare the polyurethane ink resin, and has a simple process and low cost.

[0006] The present invention also provides an ink, comprising the polyurethane ink resin, so that the ink has good pigment dispersibility, covering performance, and strong substrate adhesion.

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

[0008] The polyester polyol is formed by polycondensation of diol and dibasic acid; the diol includes dimer alcohol.

[0009] In the polyurethane ink resin as described above, the dimer alcohol comprises Pripol 2030 and / or Pripol 2033.

[0010] The polyurethane ink resin as described above, wherein the diol further comprises a small molecule diol;

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

[0012] The polyurethane ink resin as described above, wherein 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] In the polyurethane ink resin as described above, the end-capping agent includes a tertiary amine having a primary amine group or a secondary amine group at one end and a tertiary amine group at the other end.

[0015] The polyurethane ink resin as described above, the end-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-propylenediamine, N,N-diethyl-1,3-propylenediamine, N,N-dipropyl-1,3-propylenediamine, N,N-diisopropylpropylenediamine, N,N-dibutyl-1,3-propylenediamine, N,N,N'-trimethyl-1,3-propylenediamine, 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), N,N-diisopropyl-1,5-pentanediamine; preferably at least any 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 as described above, wherein the small molecule diol includes at least one of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, methyl propane diol, 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; preferably includes at least one of methyl propanediol, 1,4-butanediol, neopentyl glycol, and 3-methyl-1,5-pentanediol;

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

[0018] The polyurethane ink resin as described above, wherein 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) and dicyclohexylmethane diisocyanate (HMDI);

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

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

[0021] 1) reacting a first system including polyester polyol, isocyanate, catalyst and first solvent at 60° C. to 120° C. in an inert atmosphere for 3 h to 5 h, then cooling to below 70° C., adding a second solvent to the cooled first system to obtain a prepolymer solution;

[0022] 2) Adding the prepolymer solution to a second system including 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] 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.

[0024] In the polyurethane ink resin provided by the present invention, the diol for preparing the polyester polyol includes dimer alcohol, which is a macromolecule and 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, thereby improving the anti-ink dissolving performance of the polyurethane ink resin to the solvent-free glue, and further improve the pigment dispersibility, hiding performance and adhesion to the substrate of the ink. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the modern packaging and printing industry, polyurethane solvent-free glue is widely used due to its environmentally friendly characteristics and excellent bonding performance. However, since solvent-free glue needs to meet the requirements of low working viscosity, its molecular weight is usually small. This low molecular weight characteristic makes it easy to cause ink phenomenon when compounded with polyurethane ink resin. This ink dissolving phenomenon will cause the printed pattern to lose color and blur, seriously affecting the appearance quality and market competitiveness of the product.

[0027] Traditional polyurethane ink resins are difficult to effectively resist the dissolution of glue due to their molecular structure being similar to solvent-free glue. Therefore, how to improve the anti-ink performance of ink resins has become a technical problem that needs to be solved urgently in the industry.

[0028] In order to solve the above problems, it is particularly important to develop a new type of polyurethane ink resin. This resin not only needs to have sufficient differentiation from solvent-free glue in chemical structure to improve anti-ink performance, but also needs to meet the multiple requirements of the printing industry for color and wear resistance in terms of performance.

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

[0030] Illustratively, 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 a range consisting of any two of them; the number of parts of isocyanate can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts or a range consisting of any two of them; the number of parts of amine chain extender can be 0.3 parts, 0.5 parts, 1 parts, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts or a range consisting of any two of them; the number of parts of end-capping agent can be 0.05 parts, 0.5 parts, 1 parts, 2 parts, 3 parts, 4 parts, 5 parts or a range consisting of any two of them.

[0031] In the polyurethane ink resin provided by the present invention, the diol for preparing the polyester polyol includes dimer alcohol, which can improve the anti-ink dissolving performance of the polyurethane ink resin to solvent-free glue, thereby improving the pigment dispersibility, hiding performance and adhesion to the substrate of the ink.

[0032] Specifically, in the polyurethane ink resin provided by the present invention, the polyester polyol is formed by the condensation of a diol and a dibasic acid, and the diol includes a dimer alcohol. The dimer alcohol is a macromolecule and usually contains a non-polar chain segment, which can change the molecular polarity of the polyurethane ink resin, thereby 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 anti-ink dissolving performance of the polyurethane ink resin to the solvent-free glue, and further improving the pigment dispersion, hiding performance and adhesion to the substrate of the ink.

[0033] In addition, in the polyurethane ink resin provided by the present invention, the isocyanate group (-NCO) in the raw material isocyanate can undergo an addition reaction with the hydroxyl group (-OH) in the polyol to form a polyurethane chain. This reaction is the basis for the formation of polyurethane, and through the 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] In addition, in the polyurethane ink resin provided by the present invention, the raw material amine chain extender reacts with the isocyanate group (-NCO) to form a urea bond (-NH-CO-NH), thereby extending and cross-linking the polyurethane chain. This reaction not only increases the molecular weight of the polymer, but also increases the cross-linking density of the polyurethane ink resin, and enhances the mechanical strength and chemical resistance of the polyurethane ink resin.

[0035] In addition, in the polyurethane ink resin provided by the present invention, the raw material end-capping agent is used to terminate the polyurethane synthesis reaction to prevent excessive cross-linking or chain growth. Through end-capping, the molecular weight and structure of the polymer can be accurately controlled to obtain the desired physical and chemical properties.

[0036] In the polyurethane ink resin provided by the present invention, the diol for preparing the polyester polyol includes dimer alcohol, which is a macromolecule and 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, thereby improving the anti-ink dissolving performance of the polyurethane ink resin to the solvent-free glue, and further improve the pigment dispersibility, hiding performance and adhesion to the substrate of the ink.

[0037] The dimer alcohol in the present invention comprises a main chain and alkane side chains connected to the main chain.

[0038] In some embodiments of the invention, the dimer alcohol comprises Pripol 2030 and / or Pripol 2033.

[0039] 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, thereby improving the ink-dissolving performance of the polyurethane ink resin against solvent-free glue, and on the other hand, can improve the affinity for pigments and non-polar printing substrates, that is, improve the dispersibility of the ink for the pigment, the anti-adhesion performance, the covering performance and the 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 dimer alcohol to the small molecule diol is (0.2~8):1, for example, it can be 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 a range consisting of any two of them; more preferably (0.3~3):1.

[0041] In the present invention, diols also include small molecule diols, i.e. diol compounds. Diols usually have a high molecular weight and a complex structure, while small molecule diols are relatively simple and short-chain. By adjusting the mass ratio of dimer alcohol and small molecule diol within the above range, the molecular weight and chain structure of polyester polyol can be accurately controlled, thereby affecting the physical properties of polyurethane ink resin. And the appropriate proportion of dimer alcohol can increase the crosslinking density and chemical stability of polyurethane ink resin, thereby improving its anti-ink dissolving performance to solvent-free glue. Small molecule diols help to improve the uniformity and stability of 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, 1000, 2000, 3000, 4000, 5000, 6000 or any two thereof; preferably 1000 to 4000.

[0044] In the present invention, the functionality and number average molecular weight of the polyester polyol are within the above ranges, which can adjust the hardness, flexibility and elasticity of the polyurethane ink resin, help control the crosslinking density of the polyurethane ink resin, and 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, so that it remains stable when in contact with solvents and other chemicals. In addition, it can also improve the fluidity of the polyurethane ink resin and the dispersibility of the pigment, ensuring the color uniformity and hiding power of the ink. It also helps to form a uniform polymer network, improve the adhesion of the ink to the substrate, and ensure the durability and quality of the printed matter.

[0045] In some embodiments of the present invention, the end-capping agent includes a tertiary amine having a primary or secondary amine group at one end and a tertiary amine group at the other end. Further, the end-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-propylenediamine, N,N-diethyl-1,3-propylenediamine, N,N-dipropyl-1,3-propylenediamine, N,N-diisopropylpropylenediamine, N,N-dibutyl-1,3-propylenediamine, N,N,N'-trimethyl-1,3-propylenediamine, N,N,2,2-tetramethyl -1,3-propylenediamine, 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), N,N-diisopropyl-1,5-pentanediamine; preferably includes at least any one of N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dimethyl-1,3-propylenediamine, and N,N-diethyl-1,3-propylenediamine.

[0046] The end-capping agent in the present invention includes a tertiary amine having a primary or secondary amine group at one end and a tertiary amine group at the other end. By introducing a functional tertiary amine at the end of the polyurethane ink resin molecule, the polarity of the polyurethane ink resin can be changed, and the anti-solvent ink performance of the polyurethane ink resin to solvent-free glue can be improved, thereby improving the dispersibility, anti-adhesion performance, hiding performance and adhesion to the substrate of the pigment in the ink, and reducing the risk of pattern discoloration during printing. The use of the end-capping agent can adjust the rheological properties of the polyurethane ink resin, so that it has better fluidity and stability during processing and application.

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

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

[0049] The small molecule 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.

[0050] The above-mentioned dibasic acid in the present invention can enhance the mechanical properties of the polyurethane ink resin, such as tensile strength and tear resistance, and also affect 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.

[0051] 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) and dicyclohexylmethane diisocyanate (HMDI).

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

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

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

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

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

[0057] In the method for preparing 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.

[0058] In step 1), the first solvent includes esters and / or alcohols, for example, secondary alcohols and 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. The second solvent includes esters and / or alcohols, for example, secondary alcohols and 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. The preparation method of polyester polyols can be prepared according to the preparation method of polyester polyols known in the art, for example, adding dimer alcohol, small molecule diol, dibasic acid and tetrabutyl titanate (as a catalyst) into a reactor, passing nitrogen, stirring and reacting at 150°C~260°C for 24h~36h to obtain polyester polyols.

[0059] The first system including polyester polyol, isocyanate, catalyst and first solvent is put into a container, and an inert gas, such as nitrogen, is reacted at 60°C~120°C for 3h~5h and then cooled to below 70°C, and then the second solvent is added to the first system after cooling. The addition of the second solvent can reduce the viscosity of the first system to obtain a prepolymer solution. Among them, 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-heptane dione acid zirconium, bismuth neodecanoate and bismuth 2-ethylhexanoate; preferably dibutyltin dilaurate, bismuth neodecanoate and bismuth 2-ethylhexanoate, more preferably bismuth neodecanoate. The amount of catalyst added can be the conventional amount used in the art.

[0060] In step 2), the third solvent includes esters and / or alcohols, for example, secondary alcohols and 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. The amine chain extender, the end capping agent, and the third solvent are stirred evenly to obtain the second system. Then, under stirring at room temperature, the prepolymer solution is added within 0.5h~2h, that is, added dropwise to the second system, which can control the polymerization rate of the polyurethane ink resin to obtain the polyurethane ink resin.

[0061] The preparation method of the polyurethane ink resin provided by the present invention can prepare the above-mentioned polyurethane ink resin, and the polyurethane ink resin has good anti-ink performance to solvent-free glue, thereby improving the pigment dispersibility, hiding performance and adhesion to the substrate of the ink.

[0062] 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.

[0063] 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 pigment dispersibility, hiding performance, and strong substrate adhesion.

[0064] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0065] The raw materials used in the embodiments 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] Dimer alcohol, Pripol 2030, Pripol 2033, Cargill;

[0070] Methylpropanediol, MPO, Dalian, Taiwan, China;

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

[0072] Neopentyl glycol, NPG, Wanhua Chemical;

[0073] Adipic acid, AA, Huafeng Chemical;

[0074] Tetrabutyl titanate, Aladdin;

[0075] Polyester polyol 2000PM, obtained by reaction of adipic acid and methyl propanediol, number average molecular weight 2000, Asahikawa Chemical;

[0076] BICAT8118, an organobismuth catalyst, a leading American chemistry from the United States;

[0077] Isophorone diamine, IPDA, Wanhua Chemical;

[0078] Ethylenediamine, EDA, Inokite;

[0079] N,N-dimethylethylenediamine, DMEDA, Inokite;

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

[0081] N,N-dimethyl-1,3-propanediamine, DMPDA, Inokite;

[0082] N,N-diethyl-1,3-propanediamine, DEPDA, Inokite;

[0083] N,N-dibutylethylenediamine, DBEDA, Inokite;

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

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

[0086] Isopropyl alcohol, IPA, China's Jinzhou Petrochemical.

[0087] The preparation method of polyester polyol B1 includes the following steps: 528.4g of Pripol2030, 176.1g of MPO (the mass ratio of Pripol2030 to MPO is 3:1), 392.1g of AA and 0.05g of catalyst tetrabutyl titanate are added into a flask, nitrogen is passed through, stirring evenly, heating to 230°C, reacting for 24h, and dehydrating to obtain polyester polyol B1, which has a number average molecular weight of about 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 comprises the following steps: adding 307.9 g of Pripol 2030, 307.9 g of BDO (the mass ratio of Pripol 2030 to BDO is 1:1), 509.8 g of AA and 0.05 g of tetrabutyl titanate catalyst into a flask, passing nitrogen, stirring evenly, heating to 230° C., reacting for 32 hours, and dehydrating to obtain polyester polyol B2, which has a number average molecular weight of about 2000, a hydroxyl value of 56 mgKOH / g, an acid value of 0.25 mgKOH / 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 into a flask, nitrogen is passed through, stirring evenly, heating to 230°C, reacting for 36h, and dehydrating to obtain polyester polyol B3, which has a number average molecular weight of about 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 Pripol2033, 482.9g of MPO (the mass ratio of Pripol2033 to MPO is 0.2:1), 558.1g of AA and 0.05g of tetrabutyl titanate catalyst are added into a flask, nitrogen is passed through, stirring evenly, heating to 230°C, reacting for 36h, and dehydrating to obtain polyester polyol B4, which has a number average molecular weight of about 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: adding 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 into a flask, passing nitrogen, stirring evenly, heating to 230°C, reacting for 36h, and dehydrating to obtain polyester polyol B5, which has a number average molecular weight of about 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 of the present embodiment comprises the following steps:

[0094] 100 g of polyester polyol B1, 11.46 g of IPDI, 0.03 g of Bicat8118, and 30 g of EA were put into a flask, nitrogen was passed through, and the mixture was reacted at 75° C. for 5 h. After the temperature was lowered to below 70° C., 50 g 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 evenly 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 within 0.5 h to obtain the polyurethane ink resin Eg1.

[0096] Example 2

[0097] The preparation method of the polyurethane ink resin of the present embodiment comprises the following steps:

[0098] 100 g of polyester polyol B2, 15.71 g of IPDI, 0.03 g of Bicat8118, and 30 g of EA were put into a flask, nitrogen was passed through, and the mixture was reacted at 75° C. for 4 h. After the temperature was lowered to below 70° C., 50 g 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 evenly 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 within 0.5 h to obtain the polyurethane ink resin Eg2.

[0100] Example 3

[0101] The preparation method of the polyurethane ink resin of the present embodiment comprises the following steps:

[0102] 100 g of polyester polyol B3, 26.24 g of IPDI, 0.03 g of Bicat8118 and 30 g of EA were put into a flask, nitrogen was passed through, and the mixture was reacted at 75° C. for 3 h. After the temperature was lowered to below 70° C., 50 g of EA was added to obtain a prepolymer solution.

[0103] In another flask, add 2.76g of IPDA, 0.38g of N,N-dimethylethylenediamine, 146.4g of EA and 75.5g of IPA, stir evenly to obtain a chain extender solution, i.e., the second system, and then add the above prepolymer solution dropwise to the second system under stirring at room temperature within 0.5h to obtain the polyurethane ink resin Eg3.

[0104] Example 4

[0105] 100 g of polyester polyol B1, 11.46 g of IPDI, 0.03 g of Bicat8118, and 30 g of EA were put into a flask, nitrogen was passed through, and the mixture was reacted at 75° C. for 5 h. After the temperature was lowered to below 70° C., 50 g of EA was added to obtain a prepolymer solution.

[0106] In another flask, add 4.29g of IPDA, 0.62g of N,N-diethylethylenediamine, 123.6g of EA and 67.9g of IPA, stir evenly to obtain a chain extender solution, i.e., the second system, and then add the above prepolymer solution dropwise to the second system under stirring at room temperature within 0.5h to obtain the polyurethane ink resin Eg4.

[0107] Example 5

[0108] The preparation method of the polyurethane ink resin of the present embodiment comprises the following steps:

[0109] 100 g of polyester polyol B2, 15.71 g of IPDI, 0.03 g of Bicat8118, and 30 g of EA were put into a flask, nitrogen was passed through, and the mixture was reacted at 75° C. for 4 h. After the temperature was lowered to below 70° C., 50 g 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-propylenediamine, 128.9 g of EA and 69.6 g of IPA were added and stirred evenly 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 within 0.5 h to obtain the polyurethane ink resin Eg5.

[0111] Example 6

[0112] The preparation method of the polyurethane ink resin of the present embodiment comprises the following steps:

[0113] 100 g of polyester polyol B3, 26.24 g of IPDI, 0.03 g of Bicat8118 and 30 g of EA were put into a flask, nitrogen was passed through, and the mixture was reacted at 75° C. for 3 h. After the temperature was lowered to below 70° C., 50 g of EA was added to obtain a prepolymer solution.

[0114] In another flask, add 2.70g of IPDA, 0.66g of N,N-diethyl-1,3-propylenediamine, 146.8g of EA and 75.6g of IPA, stir evenly to obtain a chain extender solution, i.e., the second system, and then add the above prepolymer solution dropwise to the second system under stirring at room temperature within 0.5h to obtain the polyurethane ink resin Eg6.

[0115] Example 7

[0116] The preparation method of the polyurethane ink resin of the present embodiment comprises the following steps:

[0117] 100 g of polyester polyol B1, 13.64 g of HMDI, 0.03 g of Bicat8118 and 30 g of EA were put into a flask, nitrogen was passed through, and the mixture was reacted at 75° C. for 5 h. After the temperature was lowered to below 70° C., 50 g 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 evenly 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 within 0.5 h to obtain the polyurethane ink resin Eg7.

[0119] Example 8

[0120] The preparation method of the polyurethane ink resin of the present embodiment comprises the following steps:

[0121] 100 g of polyester polyol B2, 12.20 g of TDI-80, 0.03 g of Bicat8118 and 30 g of EA were put into a flask, nitrogen was passed through, and the mixture was reacted at 75° C. for 3 h. After the temperature was lowered to below 70° C., 50 g of EA was added to obtain a prepolymer solution.

[0122] In another flask, add 3.07g of IPDA, 0.56g of N,N-diethylethylenediamine, 122.7g of EA and 67.6g of IPA, stir evenly to obtain a chain extender solution, i.e., the second system, and then add the above prepolymer solution dropwise to the second system under stirring at room temperature within 0.5h to obtain the polyurethane ink resin Eg8.

[0123] Example 9

[0124] The preparation method of the polyurethane ink resin of the present embodiment comprises the following steps:

[0125] 100 g of polyester polyol B2, 15.71 g of IPDI, 0.03 g of Bicat8118, and 30 g of EA were put into a flask, nitrogen was passed through, and the mixture was reacted at 75° C. for 4 h. After the temperature was lowered to below 70° C., 50 g of EA was added to obtain a prepolymer solution.

[0126] In another flask, add 1.18g of EDA, 0.71g of N,N-dibutylethylenediamine, 125.8g of EA and 68.6g of IPA, stir evenly to obtain a chain extender solution, i.e., the second system, and then add the above prepolymer solution dropwise to the second system under stirring at room temperature within 0.5h to obtain the polyurethane ink resin Eg9.

[0127] Example 10

[0128] The preparation method of the polyurethane ink resin of the present embodiment comprises the following steps:

[0129] 100 g of polyester polyol B3, 26.24 g of IPDI, 0.03 g of Bicat8118 and 30 g of EA were put into a flask, nitrogen was passed through, and the mixture was reacted at 75° C. for 3 h. After the temperature was lowered to below 70° C., 50 g of EA was added to obtain a prepolymer solution.

[0130] In another flask, add 2.76g of IPDA, 0.56g of di-n-butylamine, 146.7g of EA and 75.6g of IPA, stir evenly to obtain a chain extender solution, i.e., the second system, and then add the above prepolymer solution dropwise to the second system under stirring at room temperature within 0.5h to obtain the polyurethane ink resin Eg10.

[0131] Embodiment 11

[0132] The preparation method of the polyurethane ink resin of the present embodiment comprises the following steps:

[0133] 100 g of polyester polyol B4, 26.24 g of IPDI, 0.03 g of Bicat8118 and 30 g of EA were put into a flask, nitrogen was passed through, and the mixture was reacted at 75° C. for 3 h. After the temperature was lowered to below 70° C., 50 g 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 evenly 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 within 0.5 h to obtain the polyurethane ink resin Eg11.

[0135] Example 12

[0136] The preparation method of the polyurethane ink resin of the present embodiment comprises the following steps:

[0137] 100 g of polyester polyol B5, 11.46 g of IPDI, 0.03 g of Bicat8118 and 30 g of EA were put into a flask, nitrogen was passed through, and the mixture was reacted at 75° C. for 5 h. After the temperature was lowered to below 70° C., 50 g of EA was added to obtain a prepolymer solution.

[0138] In another flask, add 4.07g of IPDA, 0.56g of N,N-dimethylethylenediamine, 123.1g of EA and 67.7g of IPA, stir evenly to obtain a chain extender solution, i.e., the second system, and then add the above prepolymer solution dropwise to the second system under stirring at room temperature within 0.5h to obtain the polyurethane ink resin Eg12.

[0139] Comparative Example 1

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

[0141] 100 g of polyester polyol 2000PM, 15.71 g of IPDI, 0.03 g of Bicat8118 and 30 g of EA were put into a flask, nitrogen was passed through, and the mixture was reacted at 75° C. for 4 h. After the temperature was lowered to below 70° C., 50 g 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 evenly 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 within 0.5 h to obtain the polyurethane ink resin C1.

[0143] Table 1 Formulations of polyurethane ink resins of 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 ink according to the formula in Table 2. The raw materials were placed in a 500 mL iron can, and then an equal mass of 1 mm diameter glass beads were added. After sealing, the can was ground with a coating rapid mixer for 3 h to 4 h to obtain a polyurethane ink for gravure printing.

[0146] Table 2 Polyurethane gravure ink formula

[0147]

[0148] The prepared polyurethane ink for gravure printing was tested as follows:

[0149] (1) Ink gloss test method

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

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

[0152] (2) Ink adhesion test method

[0153] Reference GB / T13217.7-2009.

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

[0155] The evaluation criteria are: ◎ means more than 90% ink residue; ○ means 60-90% ink residue; × means less than 50% ink residue.

[0156] (3) Ink resolubility test method

[0157] 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 was dry, about 1 gram to 2 grams of the test solvent was taken with a dropper and quickly dropped on the ink layer of the printing plate, and then the time was counted; after 30 seconds, the solvent was blown away with a hair dryer to expose the ink layer and printing plate covered with the solvent, and the dissolution of the ink layer was observed.

[0158] Evaluation criteria for the re-solubility 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.

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

[0160] Use KPP gravure ink proofer to proof the ink. After the ink on the printing plate is dry, use KPP gravure ink proofer to apply solvent-free composite glue and observe the state of the coated surface. The higher the gloss, the better the leveling property of the glue.

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

[0162] (5) Solvent-free glue ink dissolution test

[0163] The ink was proofed using a KPP gravure ink proofer. After the ink on the printing plate was dry, the solvent-free composite glue was also applied using the KPP gravure ink proofer. Then, the plate was laminated with the PET aluminized film. The state of the ink layer was observed after 30 minutes.

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

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

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

[0167] (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.

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

[0169] Table 3 Polyurethane gravure ink white ink test results

[0170]

[0171] As can be seen from Table 3, in the polyurethane ink resin provided by the present invention, the diol for preparing the polyester polyol includes dimer alcohol, which is a macromolecule and usually contains a non-polar 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, and reduce the structural similarity between the polyurethane ink resin and the solvent-free glue, thereby improving the anti-ink dissolving performance of the polyurethane ink resin to the solvent-free glue, and can also improve the pigment dispersibility and hiding performance of the ink, and can also improve 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, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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: The method is prepared by reacting raw materials including the following components in parts by weight: 18 to 34 parts of polyester polyol, 2 to 8 parts of isocyanate, 0.3 to 6 parts of amine chain extender, and 0.05 to 5 parts of end-capping agent; The polyester polyol is formed by polycondensation of diol and dibasic acid; the diol includes dimer alcohol.

2. The polyurethane ink resin according to claim 1, characterized in that: The dimer alcohol includes Pripol 2030 and / or Pripol 2033.

3. The polyurethane ink resin according to claim 1 or 2, characterized in that: The diols also include small molecule diols; Preferably, the mass ratio of the dimer alcohol to the small molecule diol is (0.2-8):1; more preferably (0.3-3):

1.

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, preferably 2; The number average molecular weight of the polyester polyol is 1000-6000, preferably 1000-4000.

5. The polyurethane ink resin according to any one of claims 1 to 4, characterized in that: The end-capping agent includes a tertiary amine having a primary or secondary amine group at one end and a tertiary amine group at the other end.

6. The polyurethane ink resin according to any one of claims 1 to 5, characterized in that: The end-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-propylenediamine, N,N-diethyl-1,3-propylenediamine, N,N-dipropyl-1,3-propylenediamine, N,N-diisopropylpropylenediamine, N,N-dibutyl-1,3-propylenediamine, N,N,N'-trimethyl-1,3-propylenediamine, N,N,2,2-tetramethyl- 1,3-propylenediamine, 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), N,N-diisopropyl-1,5-pentanediamine; preferably at least any one of N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dimethyl-1,3-propylenediamine, and N,N-diethyl-1,3-propylenediamine.

7. The polyurethane ink resin according to claim 3, characterized in that: The small molecule diol includes at least one of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, methyl propane diol, 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; preferably includes at least one of methyl propanediol, 1,4-butanediol, neopentyl glycol, and 3-methyl-1,5-pentanediol; And / or, the dibasic acid includes at least any one of sebacic acid, adipic acid, azelaic acid, terephthalic acid, isophthalic acid, and phthalic acid; preferably includes at least any one of sebacic acid, adipic acid, and azelaic acid; more preferably includes adipic acid.

8. The polyurethane ink resin according to any one of claims 1 to 7, characterized in that: 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) and dicyclohexylmethane diisocyanate (HMDI); And / or, the amine chain extender includes at least one of isophoronediamine, ethylenediamine, propylenediamine, 1,4-butylenediamine, neopentyldiamine, 1,6-hexanediamine, octanediamine, decanediamine, dodecylamine, dicyclohexylmethanediamine, and 1,4-cyclohexenediamine; preferably includes at least one of isophoronediamine and ethylenediamine.

9. A method for preparing the polyurethane ink resin according to any one of claims 1 to 8, characterized in that: The following steps are involved: 1) reacting a first system including polyester polyol, isocyanate, catalyst and first solvent at 60° C. to 120° C. in an inert atmosphere for 3 h to 5 h, then cooling to below 70° C., adding a second solvent to the cooled first system to obtain a prepolymer solution; 2) Adding the prepolymer solution to a second system including an amine chain extender, a capping agent, and a third solvent within 0.5 h to 2 h to obtain the polyurethane ink resin.

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

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