Heterogeneous binder, method for its production and flexographic printing plate

Abstract

The application provides a heterogeneous adhesive, a preparation method thereof and a flexible printing plate. The heterogeneous adhesive is a polymer; a main chain of the polymer is a polyester structure; the polymer comprises a catechol group and a primary hydroxyl group; and the catechol group and the primary hydroxyl group are located on the main chain and / or a side chain of the polymer. In this way, by arranging the catechol group and the primary hydroxyl group on the polyester structure, a strong and tough adhesive layer can be formed between a metal base and a hydroxyl-rich resin photosensitive layer, and the viscosity of the polymer can be reduced, so that the polymer can be adhered to the metal base and the photosensitive layer by brushing or spraying, and the operation is simple and easy to process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible materials, in particular to a heterogeneous adhesive and a preparation method thereof and a flexible printing plate. BACKGROUND

[0002] The flexible printing plate is composed of a metal substrate, a bonding layer and a photosensitive layer. The bonding force of the bonding layer determines the service life of the flexible printing plate. If the bonding force is small, the photosensitive layer and the metal substrate are easy to separate during application, and uneven bonding force may cause uneven surface of the flexible printing plate, resulting in stains or missing in the printed products.

[0003] In related technologies, in order to improve the bonding force of the bonding layer, most of the focus is on the bonding of homogeneous materials, that is, the same material is bonded together.

[0004] However, the above method can achieve strong adsorption, but cannot control the bonding strength of the bonding layer, and has low applicability. SUMMARY

[0005] The present application aims to at least solve one of the technical problems in the related art.

[0006] To this end, the first aspect of the present application is to provide a heterogeneous adhesive.

[0007] The second aspect of the present application is to provide a preparation method of the heterogeneous adhesive.

[0008] The third aspect of the present application is to provide a flexible printing plate.

[0009] Therefore, according to the first aspect of the present application, a heterogeneous adhesive is provided for a flexible printing plate, the flexible printing plate having a metal substrate; the heterogeneous adhesive is a polymer; the main chain of the polymer is a polyester structure; the polymer includes a catechol group and a primary hydroxyl group; the catechol group and the primary hydroxyl group are located on the main chain and / or the side chain of the polymer.

[0010] The polyester structure has good oil resistance and corrosion resistance, and is less damaged by acid and alkali, so the polyester structure has good stability and is not easy to be damaged, and is very suitable for printing processing; at the same time, the polyester structure has good adhesion to various metals and non-metals, thereby helping to improve the adhesion performance of the adhesive and the stability of the bonding. Further, the catechol group has excellent adhesion performance, especially in a humid or underwater environment, and this group can form strong interaction with the surface of various materials, including metals, ceramics, glass, and various organic and inorganic materials; therefore, by providing catechol groups on the polyester structure, the catechol groups are easy to combine with the metal substrate of the flexible printing plate, thereby helping to improve the bonding force and stability of the bonding between the adhesive layer and the metal substrate. Finally, the primary hydroxyl group is easy to chemically react with other functional groups, so that by providing a primary hydroxyl group on the polyester structure, the primary hydroxyl group is easy to form a chemical coupling with the functional groups of the hydroxyl-rich resin photosensitive layer, thereby helping to improve the adhesion between the adhesive layer and the photosensitive layer.

[0011] Therefore, in the above embodiment, by providing catechol groups and primary hydroxyl groups on the polyester structure, it can help to form a strong and tough adhesive layer between the metal substrate and the photosensitive layer, and at the same time, the viscosity of the polymer can be reduced, so that the metal substrate and the photosensitive layer can be adhered by brushing or spraying, which is simple to operate and easy to process.

[0012] In some technical solutions, optionally, the polymer comprises a first repeating unit and a second repeating unit.

[0013] The structural formula of the first repeating unit is:

[0014] Wherein, x is the number of the first repeating unit.

[0015] The structural formula of the second repeating unit is:

[0016] Wherein, y is the number of the second repeating unit.

[0017] The structural formula of the polymer is:

[0018]

[0019] In the above technical solutions, the first repeating unit is a polyester repeating unit containing catechol groups, and the second repeating unit is a polyester repeating unit containing primary hydroxyl groups. In this way, the adhesion performance of the polymer can be effectively improved, and at the same time, the polymer has more branched chains, thereby helping to reduce the viscosity of the polymer and improve the processing performance of the polymer.

[0020] According to a second aspect of the present application, the present application provides a preparation method of the heterogeneous adhesive, comprising the following steps:

[0021] adding dopamine hydrochloride and pentanediol diacrylate into the solvent to obtain a first solution;

[0022] adding ethanolamine and a catalyst into the first solution to obtain a second solution by heating reaction;

[0023] adding the second solution into deionized water to obtain a third solution by stirring; the third solution is a suspension containing precipitated polymers;

[0024] performing solid-liquid separation on the third solution to obtain the precipitated polymers;

[0025] performing drying treatment on the precipitated polymers to obtain the finished heterogeneous adhesive.

[0026] In the above technical solution, the pentanediol diacrylate is allowed to undergo polymerization reaction to obtain polymers with polyester structure, and the dopamine hydrochloride contains catechol groups and the ethanolamine contains primary hydroxyl groups, so catechol groups and primary hydroxyl groups are introduced into the polymers through the dopamine hydrochloride and the ethanolamine, thereby obtaining the polymer adhesive with polyester structure.

[0027] The polyester structure has good oil resistance and corrosion resistance, and is less damaged by acid and alkali, so the polyester structure has good stability and is not easy to be damaged, and is very suitable for printing processing; at the same time, the polyester structure has good adhesion to various metals and non-metals, thereby helping to improve the adhesion performance and stability of the adhesive. Further, the catechol group has excellent adhesion performance, especially in humid or underwater environments, and this group can form strong interactions with the surfaces of various materials, including metals, ceramics, glass, and various organic and inorganic materials; therefore, the introduction of catechol groups on the polyester structure facilitates the combination of the catechol groups and the metal substrate of the flexible printing plate, thereby helping to improve the adhesion and stability between the adhesive layer and the metal substrate. Finally, the primary hydroxyl group is easy to react with other functional groups, so by introducing the primary hydroxyl group on the polyester structure, the primary hydroxyl group is easy to form chemical coupling with the functional groups of the photosensitive layer, thereby helping to improve the adhesion between the adhesive layer and the photosensitive layer.

[0028] Therefore, in the above technical solution, by introducing catechol groups and primary hydroxyl groups on the polyester structure, it is possible to help form a strong and tough adhesive layer between the metal substrate and the photosensitive layer, and at the same time, the viscosity of the polymer can be reduced, so that the metal substrate and the photosensitive layer can be adhered by brushing, which is simple to operate and easy to process.

[0029] In some embodiments, the drying process is freeze-drying. Freeze-drying is a drying method that removes water from a product by sublimation at low temperature. This method can better maintain the chemical structure and physical form of the product, which can reduce the loss of heat-sensitive components in the adhesive and improve the adhesion of the adhesive.

[0030] In some embodiments, the molar ratio of dopamine hydrochloride to ethanolamine is in the range of (0, 2) : (0, 2). In this way, by controlling the molar ratio of dopamine hydrochloride to ethanolamine, the relative content of catechol groups and primary hydroxyl groups in the entire reaction system can be adjusted to ensure that the reaction can proceed smoothly. At the same time, it can also affect the cross-linking density, molecular chain length and other structural characteristics of the adhesive to achieve the desired product performance.

[0031] In some embodiments, the catalyst is a basic compound, and / or the solvent is a water-miscible organic solvent.

[0032] In the preparation of the adhesive, the amino groups in the dopamine hydrochloride and ethanolamine molecules become more active under the catalysis of the basic catalyst, and can more easily attack molecules containing double bonds to form stable C-N bonds. This addition reaction not only enhances the intermolecular interaction, but also promotes the formation of cross-linked structures. In this way, the simple and efficient Michael addition reaction of amino groups and double bonds helps to accelerate the reaction between dopamine hydrochloride, ethanolamine and other reactants, and promotes the formation of cross-linked structures, thereby improving the adhesion and stability of the adhesive. Secondly, water-miscible organic solvents not only have good solubility and can fully dissolve the reactants to make the reaction more uniform and efficient, but also can form a homogeneous system with water, which is conducive to the subsequent deionized water treatment and the formation of precipitated polymers.

[0033] In some embodiments, the catalyst can be any known basic catalyst. Illustratively, the catalyst includes at least one of triethylamine, tetramethylguanidine, 1,8-diazabicycloundec-7-ene (DBU), triazabicyclodec-5-ene (TBD), sodium hydroxide, potassium hydroxide, and lithium hydroxide.

[0034] In some embodiments, the solvent includes at least one of dimethylformamide, dimethylacetamide, methylpyrrolidone, and dioxane.

[0035] In some embodiments, the above adding ethanolamine and catalyst to the first solution to obtain the second solution by heating reaction specifically includes:

[0036] The ethanolamine and the catalyst are added to the first solution in a dropwise manner to obtain an intermediate solution;

[0037] The intermediate solution is heated to obtain a second solution.

[0038] In the above technical solution, the ethanolamine and the catalyst are added to the first solution in a dropwise manner, which can ensure that these reactants gradually enter the reaction system at a stable rate, avoiding problems such as excessive local concentration, excessively fast reaction rate, or increased side reactions caused by adding too many reactants at once, thereby helping to achieve a more uniform and more controllable reaction process. During the dropwise addition process, the dropwise addition speed can be adjusted as needed to adapt to the actual needs of the reaction system.

[0039] According to a third aspect of the present application, the present application further provides a flexible printing plate, which comprises a metal substrate, a photosensitive layer, and a bonding layer arranged between the metal substrate and the photosensitive layer.

[0040] The photosensitive layer is formed of polyvinyl alcohol. The bonding layer is formed of the heterogeneous bonding agent provided in the first aspect of the present application, or the bonding layer is formed of the heterogeneous bonding agent prepared by the preparation method of the heterogeneous bonding agent provided in the second aspect of the present application. Therefore, the flexible printing plate has all the beneficial effects of any of the above technical solutions, which will not be repeated here.

[0041] Additional aspects and advantages of the present application will become apparent in the description that follows, or can be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0042] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the optionally implementable embodiments. The drawings are for purposes of illustration only and are not considered a limitation of the present application. Moreover, like reference numerals in the attached figures are used to denote like components. In the drawings:

[0043] Figure 1 A structural schematic diagram of a flexible printing plate in an embodiment of the present application is shown.

[0044] wherein, Figure 1 The correspondence between the reference numerals and the component names in the drawings is as follows:

[0045] 10 - flexible printing plate; 100 - metal substrate; 200 - bonding layer; 300 - photosensitive layer. DETAILED DESCRIPTION

[0046] In order to enable a more clear understanding of the above-mentioned objects, features and advantages of the present application, the present application will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0047] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, however, the present application can also be implemented in other manners different from those described herein, and therefore, the protective scope of the present application is not limited to the specific embodiments disclosed below.

[0048] In a first aspect of the present application, a heterogeneous adhesive for a flexible printing plate having a metal substrate is provided. The heterogeneous adhesive is a polymer having a polyester structure in the main chain, and the polymer comprises catechol groups and primary hydroxyl groups on the main chain and / or side chain of the polymer.

[0049] The heterogeneous adhesive of the present application has good oil resistance and stability, and can form a strong and tough adhesive layer between the metal substrate and the hydroxyl-rich resin photosensitive layer. At the same time, the adhesive has low viscosity and good dispersibility, so that it can be adhered to the metal substrate and the photosensitive layer by brushing, which is simple to operate and easy to process.

[0050] At present, the adhesive layer of the flexible printing plate is prepared by using a double-curing technology, i.e., first, the hydroxyl groups react with isocyanate to form a semi-crosslinked structure by thermal curing, and then the adhesive layer plays a bonding role by the reaction of carbon-carbon unsaturated bonds by photocuring, so as to realize the bonding of the substrate and the photosensitive layer.

[0051] However, the adhesive layer prepared by this method has contradictory storage stability and oil resistance. When the adhesive layer on the support film (the substrate with the adhesive layer) has good oil resistance, the adhesion between the adhesive layer and the substrate becomes poor after the support film is stored for a period of time, which leads to the peeling of the photosensitive layer from the substrate during use, and the flexible printing plate cannot be used normally. When the support film has good storage stability and can be stored for a long time without the adhesion between the adhesive layer and the substrate being attenuated, the oil resistance of the adhesive layer becomes poor. During the plate making process or the printing process, the photosensitive layer peels off from the substrate, and the flexible printing plate cannot be used, or the adhesion is not uniform, which affects the quality of the printed product.

[0052] Taking polyvinyl alcohol (PVA) as the photosensitive layer and a metal substrate as an example, when the flexible printing plate is prepared, although the polyvinyl alcohol has good adhesion, its chemical inertness is relatively high, and the chemical reactivity on the surface of the polyvinyl alcohol is low, so it is difficult to form strong chemical bonding with the metal substrate. In addition, the molecular chain of the polyvinyl alcohol is long and irregular, and the viscosity is high, which also increases the difficulty of bonding with the metal substrate.

[0053] The inventors have found through experiments that the polyester structure has good oil resistance and corrosion resistance, and is less damaged by acid and alkali, and thus has good stability and is not easily damaged, and is very suitable for printing processing. At the same time, the polyester structure has good adhesion to various metals and non-metals, thereby helping to improve the adhesion performance of the adhesive and the stability of the bonding. Further, the catechol group has excellent adhesion performance, especially in humid or underwater environments, and this group can form strong interactions with the surfaces of various materials, including metals, ceramics, glass, and various organic and inorganic materials; thus, by providing catechol groups on the polyester structure, the catechol groups are easily combined with the metal substrate of the flexible printing plate, thereby helping to improve the bonding force and stability of the bonding between the bonding layer and the metal substrate. Finally, the primary hydroxyl group is easily chemically reacted with other functional groups, so that by providing a primary hydroxyl group on the polyester structure, the primary hydroxyl group is easily chemically coupled with the functional groups of the photosensitive layer, thereby helping to improve the adhesion between the bonding layer and the photosensitive layer, and the remaining primary hydroxyl group can also be chemically crosslinked with polyvinyl alcohol through diisocyanate, thereby achieving the regulation of the bonding strength of the bonding layer.

[0054] Therefore, in the preparation of a flexible printing plate, the heterogeneous adhesive of the present application can form a strong and tough bonding layer between the metal substrate and the photosensitive layer, and at the same time, the heterogeneous adhesive has low viscosity and good dispersibility, and can be adhered to the metal substrate and the photosensitive layer by brushing or spraying, which is simple to operate and easy to process.

[0055] In some embodiments, the polymer includes a first repeating unit and a second repeating unit.

[0056] The structure of the first repeating unit is:

[0057] x is the number of first repeating units.

[0058] The structure of the second repeating unit is:

[0059] y is the number of second repeating units.

[0060] The structure of the polymer is:

[0061]

[0062] In the above embodiment, the first repeating unit is a polyester repeating unit containing catechol groups, and the second repeating unit is a polyester repeating unit containing primary hydroxyl groups. In this way, the adhesion of the polymer can be effectively improved, and at the same time, the polymer has more branched chains, thereby helping to reduce the viscosity of the polymer and improve the processability of the polymer.

[0063] According to a second aspect of the present application, a preparation method of the heterogeneous adhesive is provided, comprising the following steps:

[0064] Dopamine hydrochloride and pentanediol diacrylate are added to a solvent to obtain a first solution;

[0065] Ethanolamine and a catalyst are added to the first solution to obtain a second solution by heating reaction;

[0066] The second solution is added to deionized water to obtain a third solution by stirring; the third solution is a suspension containing a precipitated polymer;

[0067] The third solution is subjected to solid-liquid separation to obtain a precipitated polymer;

[0068] The precipitated polymer is subjected to drying treatment to obtain a finished heterogeneous adhesive.

[0069] In the above embodiment, the polymer with a polyester structure is obtained by polymerization of pentanediol diacrylate, and the catechol groups and primary hydroxyl groups are introduced into the polymer by dopamine hydrochloride and ethanolamine, thereby obtaining the polymer heterogeneous adhesive with a polyester structure.

[0070] The polyester structure has good oil resistance and corrosion resistance, and is less damaged by acid and alkali, so it has good stability and is not easily damaged, and is very suitable for printing processing. At the same time, the polyester structure has good adhesion to various metals and non-metals, thereby helping to improve the adhesion and stability of the adhesive. Further, the catechol groups have excellent adhesion, especially in humid or underwater environments, and this group can form strong interactions with the surfaces of various materials, including metals, ceramics, glass, and various organic and inorganic materials. Therefore, the catechol groups are easily combined with the metal substrate of the flexible printing plate, thereby helping to improve the adhesion and stability between the adhesive layer and the metal substrate. Finally, the primary hydroxyl groups are easily chemically reacted with other functional groups, so that the primary hydroxyl groups are easily chemically coupled with the functional groups of the photosensitive layer, thereby helping to improve the adhesion between the adhesive layer and the photosensitive layer.

[0071] Therefore, in the above technical solution, by introducing catechol groups and primary hydroxyl groups on the polyester structure, a strong and tough bonding layer can be formed between the metal substrate and the photosensitive layer, and the viscosity of the polymer can be reduced, so that the metal substrate and the photosensitive layer can be adhered by brushing or spraying, which is simple to operate and easy to process.

[0072] In some embodiments, the drying treatment is freeze-drying, i.e., a freeze-drying treatment. The freeze-drying treatment is a drying method for removing water by sublimation at low temperature, which can better maintain the chemical structure and physical form of the product, thereby reducing the loss of heat-sensitive components in the adhesive and improving the adhesion of the adhesive.

[0073] In some embodiments, the molar ratio of dopamine hydrochloride to ethanolamine is in the interval (0, 2):(0, 2). In this way, by controlling the molar ratio of dopamine hydrochloride to ethanolamine, the relative content of catechol groups and primary hydroxyl groups in the entire reaction system can be adjusted to ensure that the reaction can proceed smoothly, and the crosslinking density, molecular chain length, and other structural characteristics of the heterogeneous adhesive can also be affected to achieve the desired product performance.

[0074] In the above embodiments, the molar ratio of dopamine hydrochloride to ethanolamine is 1:1, 0:1, 1:0, 2:1, or 1:2.

[0075] In some embodiments, the catalyst is a basic compound, and / or the solvent is a water-miscible organic solvent.

[0076] During the preparation of the heterogeneous adhesive, the amino groups in the dopamine hydrochloride and ethanolamine molecules become more active under the catalysis of the basic catalyst, and can more easily attack molecules containing double bonds to form stable C-N bonds. This addition reaction not only enhances the intermolecular interaction force, but also promotes the formation of crosslinked structures. In this way, the simple and efficient Michael addition reaction of amino groups and double bonds helps to accelerate the reaction between dopamine hydrochloride, ethanolamine, and other reactants, and promotes the formation of crosslinked structures, thereby improving the adhesion and stability of the adhesive. Secondly, water-miscible organic solvents not only have good solubility and can fully dissolve the reactants to make the reaction more uniform and efficient, but also can form a homogeneous system with water, which is conducive to subsequent deionized water treatment and the formation of precipitates.

[0077] In the above embodiments, the catalyst can be any known basic catalyst, which is not particularly limited in the present application. Illustratively, the catalyst includes at least one of triethylamine, tetramethylguanidine, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), sodium hydroxide, potassium hydroxide, and lithium hydroxide.

[0078] In the above embodiments, the catalyst is used in a molar amount of 1.1 times that of the dopamine hydrochloride.

[0079] In the above embodiments, the kind of solvent is not particularly limited in the present application, as long as it is miscible with water. Illustratively, the solvent includes at least one of dimethylformamide, dimethylacetamide, methylpyrrolidone, and dioxane.

[0080] In some embodiments, the above adding of ethanolamine and catalyst to the first solution to obtain the second solution by heating reaction specifically includes:

[0081] The ethanolamine and catalyst are added to the first solution by dropwise addition to obtain an intermediate solution.

[0082] The intermediate solution is heated to obtain the second solution.

[0083] In the above embodiments, the ethanolamine and catalyst are added to the first solution by dropwise addition, which can ensure that these reactants gradually enter the reaction system at a stable rate, avoiding problems such as excessive local concentration, excessive reaction rate, or increased side reactions caused by adding too much reactant at once, thereby helping to achieve a more uniform and more controllable reaction process. During the dropwise addition process, the dropwise addition speed can be adjusted as needed to adapt to the actual needs of the reaction system.

[0084] In the above embodiments, the temperature and time of the heating reaction are not particularly limited in the present application. For example, the heating reaction can be heating in a 90°C oil bath for 24 hours. When methylformamide is used as the solvent and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is used as the catalyst, the reaction formula for obtaining the second solution by heating reaction is as follows:

[0085]

[0086] By adding the catalyst and ethanolamine to the first solution, the second solution containing the polymer with the first repeating unit and the second repeating unit can be obtained after heating reaction.

[0087] Reference Figure 1According to a third aspect of the present application, the present application further provides a flexible printing plate 10, which comprises a metal substrate 100, a photosensitive layer 300, and a bonding layer 200 arranged between the metal substrate 100 and the photosensitive layer 300.

[0088] The photosensitive layer 300 is mainly formed of polyvinyl alcohol. The bonding layer 200 is formed of the bonding agent provided in the first aspect of the present application, or the bonding agent prepared by the preparation method of the bonding agent provided in the second aspect of the present application. Therefore, the flexible printing plate 10 has all the beneficial effects of any of the technical solutions described above, which will not be repeated here.

[0089] It can be understood that the present application also discloses a flexible printing method, which uses the flexible printing plate provided in any of the embodiments described above, thereby having all the beneficial effects of any of the embodiments described above, which will not be repeated here.

[0090] The schemes of the present application will be described below through specific examples. It should be noted that the following examples are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. If the specific technology or condition is not specified in the examples, it is performed according to the technology or condition described in the literature in the art or according to the product instruction. If the reagent or instrument is not specified by the manufacturer, it is a conventional product that can be obtained by market purchase.

[0091] Example 1

[0092] First, a certain amount of dopamine hydrochloride and pentanediol diacrylate are weighed and added to a flask containing a certain volume of methyl formamide to obtain a first solution.

[0093] Then, a certain amount of ethanolamine and triazabicyclodecene (TBD) are weighed and slowly added to the flask. After the addition is completed, the flask is placed in a 90℃ oil bath for 24h. After the reaction is completed, a second solution is obtained. The molar ratio of ethanolamine to dopamine hydrochloride is 1:1.

[0094] Subsequently, the second solution is poured into a large amount of deionized water, and after being stirred thoroughly, a third solution is obtained. The third solution is a suspension containing precipitated polymers.

[0095] Subsequently, the third solution is subjected to solid-liquid separation to obtain a precipitated polymer.

[0096] Finally, after the precipitated polymer is subjected to freeze-drying treatment, a finished product of a heterogeneous bonding agent is obtained.

[0097] Example 2

[0098] The preparation method of the heterogeneous adhesive of Example 2 is the same as that of the heterogeneous adhesive of Example 1, with the only difference being that:

[0099] The molar ratio of ethanolamine and dopamine hydrochloride is 1:0.

[0100] Example 3

[0101] The preparation method of the heterogeneous adhesive of Example 3 is the same as that of the heterogeneous adhesive of Example 1, with the only difference being that:

[0102] The molar ratio of ethanolamine and dopamine hydrochloride is 0:1.

[0103] Example 4

[0104] The preparation method of the heterogeneous adhesive of Example 4 is the same as that of the heterogeneous adhesive of Example 1, with the only difference being that:

[0105] The molar ratio of ethanolamine and dopamine hydrochloride is 1:2.

[0106] Example 5

[0107] The preparation method of the heterogeneous adhesive of Example 5 is the same as that of the heterogeneous adhesive of Example 1, with the only difference being that:

[0108] The molar ratio of ethanolamine and dopamine hydrochloride is 2:1.

[0109] Comparative Example 1

[0110] The preparation method of the heterogeneous adhesive of Comparative Example 1 is the same as that of the heterogeneous adhesive of Example 1, with the only difference being that:

[0111] No dopamine hydrochloride and ethanolamine are added.

[0112] The heterogeneous adhesives prepared in the above examples were tested for performance, and a commercially available flexible printing plate adhesive was tested according to the same method as Comparative Example 2, and the specific results are shown in Table 1.

[0113]

[0114] Table 1

[0115] As can be seen from Table 1, the peeling and bonding performance of the heterogeneous adhesive prepared in the present example is above 27.6 KN / m, and the shear bonding strength is above 10.2 MPa, which is much higher than the data in the comparative examples.

[0116] In the description of the application, "A and / or B" can include the case of A alone, the case of B alone, the case of A and B, any one of the cases, where A, B are used only for example, which can be any technical feature connected with "and / or" in the application.

[0117] In the description of the application, the meaning of "a plurality of" is two or more.

[0118] In the description of the application, all the numbers disclosed herein are approximate values. The value of each number can be varied by 10% or less, or a reasonable difference as recognized by those skilled in the art, such as 1%, 2%, 3%, 4% or 5%.

[0119] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application; unless otherwise stated, the terms used in the present application have the same meaning as commonly understood by those skilled in the art. Unless otherwise stated, the values of the parameters mentioned in the present application can be measured by various measuring methods commonly used in the art (for example, can be tested according to the method given in the embodiments of the present application).

[0120] The terms "include" and "have" and any variations thereof in the specification and claims of the present application are open expressions, i.e. include what is indicated in the present application, but do not exclude other aspects.

[0121] The above is only the preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A heterogeneous binder, characterized in that, The heterogeneous adhesive is used in a flexible printing plate, the flexible printing plate has a metal substrate; the heterogeneous adhesive is a polymer; a main chain of the polymer is a polyester structure; the polymer comprises a catechol group and a primary hydroxyl group; the catechol group and the primary hydroxyl group are located on the main chain and / or the side chain of the polymer; The polymer comprises a first repeating unit and a second repeating unit; A structural formula of the first repeating unit is: Wherein, x is the number of the first repeating unit; A structural formula of the second repeating unit is: Wherein, y is the number of the second repeating unit; A structural formula of the polymer is:

2. A method of preparing a heterogeneous binder, characterized by, Comprising the following steps: Dopamine hydrochloride and pentanediol diacrylate are added to a solvent to obtain a first solution; Ethanolamine and a catalyst are added to the first solution to obtain a second solution by heating reaction; The second solution is added to deionized water to obtain a third solution by stirring; The third solution is a suspension containing a precipitated polymer; Solid-liquid separation is performed on the third solution to obtain a precipitated polymer; The precipitated polymer is subjected to a drying treatment to obtain a finished heterogeneous adhesive.

3. The method of claim 2, wherein the heterodimeric binder is prepared by, The drying treatment is freeze-drying.

4. The method of claim 2, wherein the heterodimeric binder is prepared by, The molar ratio of the dopamine hydrochloride to the ethanolamine is in the interval (0, 2): interval (0, 2).

5. The method of claim 2, wherein the heterodimeric binder is prepared by, The catalyst is a basic compound, and / or the solvent is a water-miscible organic solvent.

6. The method of claim 5, wherein the heterodimeric binder is prepared by, The catalyst comprises at least one of triethylamine, tetramethylguanidine, 1,8-diazabicycloundec-7-ene, triazabicyclodec-5-ene, sodium hydroxide, potassium hydroxide, and lithium hydroxide.

7. The method of claim 5, wherein the heterodimeric binder is prepared by, The solvent comprises at least one of dimethylformamide, dimethylacetamide, methylpyrrolidone, and dioxane.

8. The method of preparing a heterogeneous binder according to any one of claims 2 to 7, characterized in that, The adding of the ethanolamine and the catalyst to the first solution to obtain the second solution by heating reaction specifically comprises: The ethanolamine and the catalyst are added to the first solution in a dropwise manner to obtain an intermediate solution; The intermediate solution is heated to obtain the second solution.

9. A flexographic printing plate characterized by, Comprising a metal substrate (100), a photosensitive layer (300), and an adhesive layer (200) arranged between the metal substrate (100) and the photosensitive layer (300); The photosensitive layer (300) is formed by polyvinyl alcohol; The adhesive layer (200) is formed by the heterogeneous adhesive of claim 1, or the adhesive layer (200) is formed by the heterogeneous adhesive prepared by the preparation method of the heterogeneous adhesive according to any one of claims 2 to 8.

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