Hydrophilic polymer with blocked isocyanate groups and method for producing the same and polyurethane-based material
By preparing hydrophilic polymers with blocked isocyanate groups in a specific ratio of structural units, the problems of low storage stability and low crosslinking density of blocked isocyanate groups are solved, realizing the utilization of highly active isocyanate groups and the adjustment of hydrophilicity, which is suitable for industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING UNIV OF CHEM TECH
- Filing Date
- 2023-05-12
- Publication Date
- 2026-07-14
Smart Images
Figure CN116535560B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a hydrophilic polymer with blocked isocyanate groups, a method for manufacturing the same, and polyurethane-based materials. Background Technology
[0002] Polyurethane possesses excellent abrasion resistance, low-temperature resistance, oil resistance, and oxidation resistance, making it a high-performance polymer with a wide range of applications. As a fundamental raw material in the polyurethane industry, monomers with isocyanate groups are widely used in foamed plastics, elastomers, fibers, adhesives, and coatings. However, the isocyanate group has a highly unsaturated molecular structure, resulting in high reactivity and toxicity. It readily reacts with compounds containing active hydrogen, and is particularly sensitive to moisture in the air, exhibiting poor storage stability and unsuitability for long-term storage, thus hindering its application in continuous production. Therefore, blocked isocyanate compounds have become a research hotspot.
[0003] Currently, blocked isocyanates refer to prepolymers or polyisocyanates with NCO end groups that have their NCO groups blocked with a blocking agent. Therefore, the functionality of the prepared blocked polyisocyanates is usually low (mostly between 2 and 4), and thus, they cannot effectively form a high-density cross-linked network.
[0004] To improve crosslinking density, prepolymers with NCO end groups (e.g., polymers with blocked NCO end groups) have attracted widespread attention. However, most common NCO-terminated prepolymers are formed by reacting NCO groups with polyols to generate urethane groups, which are then part of the main chain. These NCO groups are no longer reactive, resulting in significant ineffective consumption of active NCO groups during the preparation process. This leads to the inability to unblock and form active NCO groups during use, and also increases production costs and deteriorates the production environment. Furthermore, blocked prepolymer polyisocyanates often have higher unblocking temperatures (e.g., higher than the unblocking temperatures of blocked isocyanate groups in small molecule compounds), and the resulting blocking agents may have residues and toxicity.
[0005] Moreover, when used as a forming material for polyurethane, processing properties such as film-forming properties must be considered, which greatly limits further improvements to the structure of prepolymers with NCO end groups in order to solve the above problems.
[0006] Furthermore, in many applications, it is often desirable to improve the hydrophilicity (or water dispersibility) of blocked isocyanates, which requires the introduction of hydrophilic groups into their molecular structure. However, conventional preparation methods lead to complex synthetic routes, and it is also difficult to adjust the content of hydrophilic groups as needed, i.e., it is difficult to adjust the hydrophilicity.
[0007] Therefore, there is still a need for blocked polymer isocyanates that are readily available, have high utilization of isocyanate groups, can have more active isocyanate groups and hydrophilic groups, and whose amounts can be widely adjusted. Summary of the Invention
[0008] The problem the invention aims to solve
[0009] In view of the above-mentioned deficiencies in the art, the technical problem to be solved by the present invention is to provide a hydrophilic polymer with blocked isocyanate groups that has excellent and widely adjustable crosslinking and hydrophilicity, can be deblocked at a low temperature, is easy to obtain, and has a high utilization rate of isocyanate groups during preparation.
[0010] The technical problem to be solved by the present invention is to provide a method for manufacturing a hydrophilic polymer with blocked isocyanate groups. The manufacturing process does not cause ineffective consumption of isocyanate groups and is easy to implement. The obtained hydrophilic polymer with blocked isocyanate groups has excellent crosslinking and hydrophilicity and is widely adjustable. It can be deblocked at a low temperature, so it is suitable for industrial production and application.
[0011] The technical problem to be solved by the present invention is to provide a polyurethane-based material with a higher crosslinking density.
[0012] Solution for solving the problem
[0013] According to the inventor's dedicated research, the above-mentioned technical problems can be solved by implementing the following technical solution:
[0014] [1]. A hydrophilic polymer with blocked isocyanate groups, wherein the hydrophilic polymer with blocked isocyanate groups has structural unit A and structural unit B as shown in formula (3).
[0015] The structural unit A is at least one structural unit selected from the units shown in equation (1) and equation (2):
[0016]
[0017] In formulas (1) and (2), R1 is a hydrogen atom or a methyl group, R2, R3, and R4 independently represent a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, or an aryl group with 6 to 12 carbon atoms, respectively, Q represents an organic group with a capped isocyanate group, and n is 1 or 2.
[0018]
[0019] In formula (3), X represents a tetravalent organic group, Y represents an amino group or -OI, and each I independently represents a hydrogen atom, an ammonium group, or an alkali metal.
[0020] In the hydrophilic polymer with blocked isocyanate groups, one molecular chain has more than five structural units A.
[0021] The proportion of structural unit A relative to the total mass of the hydrophilic polymer with blocked isocyanate groups is 7 × 10⁻⁶. -4 Above mol / g.
[0022] [2]. The hydrophilic polymer with blocked isocyanate groups according to [1], wherein, in the hydrophilic polymer with blocked isocyanate groups, one molecular chain has five or more of the structural units B.
[0023] The proportion of structural unit B relative to the total mass of the hydrophilic polymer with blocked isocyanate groups is 4 × 10⁻⁶. -4 Above mol / g.
[0024] [3]. A hydrophilic polymer with a blocked isocyanate group according to [1] or [2], wherein in formula (3), X represents at least one group selected from the group shown in formula (x1) and the group shown in formula (x2):
[0025]
[0026] In formulas (x1) and (x2), R5 to R8 are each independently hydrogen or an alkyl group having 1 to 12 carbon atoms, and * indicates the position connected to the carbonyl group.
[0027] [4]. The polymer according to any one of [1] to [3], wherein the hydrophilic polymer with blocked isocyanate groups is derived from a polymer precursor having structural unit A' and structural unit B' as shown in formula (3'):
[0028] The structural unit A' is at least one structural unit selected from the units shown in equation (1') and equation (2'):
[0029]
[0030] The meanings of R1, R2, R3 and R4 in equations (1') and (2') are the same as those in equations (1) and (2), except that one of the two R2s is a hydrogen atom;
[0031]
[0032] The meaning of X in equation (3') is the same as the meaning of X in equation (3).
[0033] [5]. The hydrophilic polymer with blocked isocyanate groups according to [4], wherein the ratio of structural unit A' is 10 to 90 mol% and the ratio of structural unit B' is 10 to 50 mol% relative to all structural units of the polymer precursor.
[0034] [6]. A hydrophilic polymer with a blocked isocyanate group according to any one of [1] to [5], wherein the hydrophilic polymer with a blocked isocyanate group further has a structural unit C based on an electron-rich monomer having a carbon-carbon double bond.
[0035] [7]. A method for manufacturing a hydrophilic polymer with blocked isocyanate groups, comprising:
[0036] (a) A polymer precursor having structural unit A' and structural unit B' as shown in formula (3'), wherein structural unit A' is at least one structural unit selected from the units shown in formula (1') and formula (2'):
[0037]
[0038] (b) Reacting a diisocyanate compound with a capping agent to obtain a blocked isocyanate intermediate;
[0039] (c) Reacting the closed isocyanate intermediate with the structural unit A' to form structural unit A.
[0040] The structural unit A is at least one structural unit selected from the units shown in equation (1) and equation (2):
[0041]
[0042] In formulas (1'), (2'), (1), and (2), R1 is a hydrogen atom or a methyl group, R2, R3, and R4 independently represent a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, or an aryl group with 6 to 12 carbon atoms, respectively, Q represents an organic group with a capped isocyanate group, and n is 1 or 2; however, in formula (1'), one of the two R2s is a hydrogen atom;
[0043] (d) Hydrolyzing or reacting the structural unit B' with at least one selected from ammonia and alkali metal hydroxides to form the structural unit B shown in formula (3):
[0044]
[0045] In formulas (3') and (3), X represents a tetravalent organic group, Y represents an amino group or -OI, and each I independently represents a hydrogen atom, an ammonium group or an alkali metal.
[0046] [8]. According to the manufacturing method described in [7], in step (b), the diisocyanate compound is selected from at least one of isophorone diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, trimethylhexamethylene diisocyanate, dicyclohexylmethane diisocyanate or phenyl diisocyanate; the capping agent is selected from at least one of phenol, 2-pyridinephenol, 1,2-propanediol, 2-ethylhexanol, ethylene glycol ethyl ether, ethylene glycol butyl ether, diethylene glycol butyl ether, ε-caprolactam (ε-CAP), methyl ethyl ketone oxime, 3,5-dimethylpyrazole, triazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, diisopropylamine, diethyl malonate, maleimide, succinimide;
[0047] The molar ratio of the diisocyanate compound to the capping agent is 0.8 / 1 to 1.2 / 1.
[0048] [9]. According to the manufacturing method described in [7] or [8], in step (c), the molar ratio of the closed isocyanate intermediate to the structural unit A' is 0.2 / 1 to 1.2 / 1; and more than 15 mol% of all structural units A' of the polymer precursor are formed as the structural unit A.
[0049]
[10] . The manufacturing method according to any one of [7] to [9], wherein, in step (d), at least 70 mol% of all structural units B' of the polymer precursor are formed as said structural unit B.
[0050]
[11] . A polyurethane-based material, wherein the polyurethane-based material is formed by using a hydrophilic polymer with blocked isocyanate groups according to any one of [1] to [6] or by using a hydrophilic polymer with blocked isocyanate groups obtained by any one of [7] to
[10] .
[0051] The effects of the invention
[0052] By implementing the above technical solutions, the present invention can achieve the following technical effects:
[0053] (1) The hydrophilic polymer with blocked isocyanate groups of the present invention contains structural units A and B in specific amounts, thus possessing both hydrophilic groups and more active isocyanate groups, thereby achieving excellent hydrophilicity and crosslinking properties. Moreover, the amount of these functional groups can be widely adjusted, and the blocked isocyanate groups can be deblocked at lower temperatures.
[0054] In addition, the hydrophilic polymer with blocked isocyanate groups of the present invention does not require the reaction of isocyanate groups to form the polymer backbone, thus the utilization rate of isocyanate is high.
[0055] The hydrophilic polymer with blocked isocyanate groups of the present invention has low toxicity, is easy to store and does not require high storage conditions, and the highly active isocyanate groups formed can effectively extend the chain or crosslink the chain.
[0056] Furthermore, the small molecules released from the hydrophilic polymer with blocked isocyanate groups of the present invention after desealing can also undergo ring-opening reactions with active hydrogen (e.g., H connected to N, more specifically, derived from structural unit a'), thereby inhibiting the leakage of small molecules and eliminating the adverse effects of small molecule end-capping agents.
[0057] (2). The manufacturing method of the present invention with blocked isocyanate groups is simple and easy to implement, and the isocyanate utilization efficiency is high, making it particularly suitable for industrial production and application. Attached Figure Description
[0058] Figure 1 The infrared spectra of the polymer precursor (#1) obtained in step (a) of Example 1, the blocked isocyanate intermediate (#2) obtained in step (b) of Example 1, the polymer (#3) that forms structural unit A obtained in step (c) of Example 1, and the hydrophilic polymer (#4) with blocked isocyanate groups in Example 1.
[0059] Figure 2 The infrared spectra of the polymer precursor (#1) obtained in step (a) of Example 3, the blocked isocyanate intermediate (#2) obtained in step (b) of Example 3, the polymer (#3) that forms structural unit A obtained in step (c) of Example 3, and the hydrophilic polymer (#4) with blocked isocyanate groups in Example 3.
[0060] Figure 3 The image shows the differential scanning calorimetry (DSC) curve of the hydrophilic polymer with blocked isocyanate groups obtained in Example 1. Detailed Implementation
[0061] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.
[0062] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.
[0063] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.
[0064] In this specification, the range of values referred to as "value A to value B" refers to the range including the endpoint values A and B.
[0065] In this specification, the numerical ranges referred to by "above" and "below" are ranges that include endpoint values.
[0066] In this specification, the numerical ranges indicated by "greater than" and "less than" refer to the ranges excluding endpoint values.
[0067] Unless otherwise specified, "%" in this instruction manual refers to weight percentage.
[0068] In this specification, the word "may" can mean both performing a certain treatment and not performing a certain treatment, or it can mean both having a certain component and not having a certain component.
[0069] In this specification, "optional" or "optionally" means that the event or situation described below may or may not occur, and the description includes both the scenario in which the event occurs and the scenario in which the event does not occur.
[0070] In this specification, "(meth)acrylate" encompasses both "methacrylate" and "acrylate", and "(meth)acrylamide" encompasses both "methacrylamide" and "acrylamide".
[0071] In this specification, "alkyl" or "alkylene" means a straight-chain, branched, or cyclic unsubstituted "alkyl" or "alkylene", and "aryl" or "arylene" means a group having an aromatic group but without non-hydrocarbon substituents.
[0072] In this specification, repeating units formed directly by monomer polymerization, and units formed by chemically converting part or all of the substituents of repeating units formed by monomer polymerization into other substituents, are collectively referred to as "units based on...".
[0073] Unless otherwise stated, the term "particle size" used in this specification refers to "average particle size," which can be measured using a commercial particle size analyzer or scanning electron microscope.
[0074] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be between 10 and 40°C.
[0075] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.
[0076] <<Hydrophilic polymers with blocked isocyanate groups>>
[0077] The hydrophilic polymer of the present invention with blocked isocyanate groups has structural unit A and structural unit B as shown in formula (3).
[0078] The structural unit A is at least one structural unit selected from the units shown in equation (1) and equation (2):
[0079]
[0080] In formulas (1) and (2), R1 is a hydrogen atom or a methyl group, R2, R3, and R4 independently represent a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, or an aryl group with 6 to 12 carbon atoms, respectively, Q represents an organic group with a capped isocyanate group, and n is 1 or 2.
[0081]
[0082] In formula (3), X represents a tetravalent organic group, Y represents an amino group or -OI, and each I independently represents a hydrogen atom, an ammonium group, or an alkali metal.
[0083] In the hydrophilic polymer with blocked isocyanate groups, one molecular chain has more than five structural units A, and the proportion of structural units A relative to the total mass of the hydrophilic polymer with blocked isocyanate groups is 7 × 10⁻⁶. -4 Above mol / g.
[0084] Through dedicated research, the inventors discovered that the hydrophilic polymer with blocked isocyanate groups of this invention can possess hydrophilic groups and more active isocyanate groups, and the amount of these functional groups can be widely adjusted. Furthermore, the blocked isocyanate groups can be deblocked at relatively low temperatures. The hydrophilic polymer with blocked isocyanate groups of this invention also exhibits high utilization of isocyanate groups during preparation.
[0085] In some preferred embodiments, the number average molecular weight of the hydrophilic polymer with blocked isocyanate groups can be 3,000 to 70,000 g / mol, or 6,000 to 50,000 g / mol, or 20,000 to 45,000 g / mol.
[0086] Furthermore, there are no particular limitations on the method used to prepare the hydrophilic polymer with blocked isocyanate groups of the present invention, and various methods known in the art can be used. In some particularly preferred embodiments, the hydrophilic polymer with blocked isocyanate groups of the present invention is particularly preferably prepared by the method described in the following "<<Method for Manufacturing Hydrophilic Polymer with Blocked Isocyanate Groups>>".
[0087] The details of each structural unit will be described in detail below.
[0088] <Structural Unit A>
[0089] Structural unit A of the present invention is at least one structural unit selected from the units shown in formula (1) and formula (2):
[0090]
[0091] In formula (1), R1 is a hydrogen atom or a methyl group, and R2 independently represents a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, or an aryl group with 6 to 12 carbon atoms.
[0092] In some preferred embodiments, from the viewpoint of more easily achieving the technical effects of the present invention, R2 independently preferably represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an aryl group having 6 to 10 carbon atoms, and more preferably represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
[0093] In equation (1), n is 1 or 2, preferably 1.
[0094] In formula (1), Q represents an organic group having a capped isocyanate group. Here, there is no particular limitation on the linking group in Q that connects the capped isocyanate group to N, and it can be appropriately adjusted according to actual needs. However, in some preferred embodiments, the linking group in Q that connects the capped isocyanate group to N preferably includes a urethane group. Furthermore, there is no particular limitation on the number of capped isocyanate groups included in Q, and it can be appropriately adjusted according to actual needs. However, in some preferred embodiments, from the viewpoint of more easily controlling the preparation process of the polyurethane material, Q preferably includes one or two capped isocyanate groups, more preferably only one capped isocyanate group.
[0095]
[0096] In formula (2), R3 and R4 independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and preferably independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an aryl group having 6 to 10 carbon atoms, and more preferably represent a hydrogen atom or an alkyl group having 1 to 2 carbon atoms.
[0097] In equation (2), the meaning of Q is as described above in equation (1), and will not be repeated here.
[0098] In this invention, the hydrophilic polymer with blocked isocyanate groups has 5 or more structural units A in one molecular chain, for example, 10 or more, 15 or more, 30 or more, etc. The number of structural units A in one molecular chain can be appropriately adjusted according to actual conditions (e.g., application requirements and molecular chain length).
[0099] In this invention, the number of structural units in a molecular chain is calculated by the following methods: (1) the number of molecular chains is obtained by dividing the weight of the sample to be tested by the molecular weight of the polymer; (2) the total number (moles) of a structural unit (e.g., structural unit A or B) in the sample to be tested is determined by a method known in the art; and (3) the number of structural units in a molecular chain is obtained by dividing the value obtained in (2) by the value obtained in (1).
[0100] Furthermore, relative to the total mass of the hydrophilic polymer with blocked isocyanate groups, the proportion of structural unit A is 7 × 10⁻⁶. -4mol / g or higher. In this case, the density of blocked isocyanate groups, which serve as functional groups, on the hydrophilic polymer with blocked isocyanate groups is suitable. In some preferred embodiments, from the viewpoint of obtaining better technical effects from the present invention, the proportion of structural unit A relative to the total mass of the hydrophilic polymer with blocked isocyanate groups is preferably 1 × 10⁻⁶. -3 mol / g or higher, more preferably 2×10 -3 mol / g or higher, more preferably 3.5 × 10⁻⁶ -3 Above mol / g. Generally, there is no upper limit to this ratio, but preferably it can be below 0.015 mol / g.
[0101] Furthermore, there is no particular limitation on the proportion of structural unit A in the hydrophilic polymer with blocked isocyanate groups. In some preferred embodiments, the proportion of structural unit A relative to all units of the hydrophilic polymer with blocked isocyanate groups is preferably 5-50 mol%, more preferably 8-45 mol%, and even more preferably 10-40 mol%.
[0102] <Structural Unit B>
[0103] The structural unit B of the present invention is the structural unit shown in equation (3).
[0104]
[0105] In formula (3), X represents a tetravalent organic group.
[0106] In this invention, there are no particular limitations on the specific structure of X, which can be appropriately adjusted according to actual needs and preparation conditions. In some preferred embodiments, from the viewpoint of more easily obtaining the hydrophilic polymer with blocked isocyanate groups of the present invention, X is preferably a tetravalent alkyl group, that is, a group obtained by removing four hydrogens from an alkane.
[0107] In some more preferred embodiments, from the viewpoint of further readily obtaining the hydrophilic polymer with blocked isocyanate groups of the present invention, X represents at least one selected from the groups shown in formula (x1) and formula (x2):
[0108]
[0109] In formulas (x1) and (x2), R5 to R8 are each independently hydrogen or an alkyl group having 1 to 12 carbon atoms, and * indicates the position attached to the carbonyl group. More preferably, R5 to R8 are each independently hydrogen, methyl, ethyl, n-propyl, or isopropyl. Even more preferably, R5 and R6 are each independently hydrogen or methyl (particularly preferably, one of R5 and R6 is hydrogen), and R7 and R8 are both hydrogen.
[0110] In formula (3), each I independently represents a hydrogen atom, an ammonium group or an alkali metal (e.g., sodium or potassium), preferably independently representing a hydrogen atom or an ammonium group.
[0111] In formula (3), Y represents amino or -OI, preferably -OI. Here, details and preferred examples of the symbol I are as described above.
[0112] In some preferred embodiments, from the viewpoint of better imparting hydrophilicity, the hydrophilic polymer with blocked isocyanate groups has 5 or more, for example, 10 or more, 15 or more, 30 or more, structural units B in one molecular chain.
[0113] In other preferred embodiments, from the viewpoint of better imparting hydrophilicity without impairing the crosslinking properties of the hydrophilic polymer with blocked isocyanate groups, the proportion of structural unit B relative to the total mass of the hydrophilic polymer with blocked isocyanate groups is 4 × 10⁻⁶. -4 mol / g or higher. In this case, the density of hydrophilic groups on the hydrophilic polymer with blocked isocyanate groups is preferred. In some preferred embodiments, from the viewpoint of obtaining better technical effects from the present invention, the proportion of structural unit B relative to the total mass of the hydrophilic polymer with blocked isocyanate groups is preferably 1 × 10⁻⁶. -3 mol / g or higher, more preferably 2×10 -3 mol / g or higher, more preferably 3.5 × 10⁻⁶ -3 Above mol / g. Generally, there is no upper limit to this ratio, but preferably it can be below 0.01 mol / g.
[0114] <Structural Unit A' and Structural Unit B'>
[0115] The hydrophilic polymer with blocked isocyanate groups of the present invention may optionally contain structural unit A'.
[0116] Structural unit A' is at least one structural unit selected from the units shown in equation (1') and equation (2'):
[0117]
[0118] The meanings of R1, R2, R3 and R4 in equations (1') and (2') are the same as those in equations (1) and (2), but in equation (1'), one of the two R2 atoms is a hydrogen atom.
[0119] There is no particular limitation on the proportion of structural unit A' in the polymer. In some preferred embodiments, the proportion of structural unit A' is preferably 50 mol% or less, more preferably 30 mol% or less, and even more preferably 20 mol% or less, relative to all units of the hydrophilic polymer with blocked isocyanate groups.
[0120] From the viewpoint of suppressing the spillage of small molecules generated after unsealing, in some more preferred embodiments, the hydrophilic polymer with blocked isocyanate groups of the present invention comprises structural unit A'. In this case, the proportion of structural unit A' relative to all units of the hydrophilic polymer with blocked isocyanate groups is preferably 1 mol% or more, more preferably 3 mol% or more, and even more preferably 5 mol% or more.
[0121] The hydrophilic polymers of the present invention with blocked isocyanate groups may optionally include structural unit B' as shown in formula (3').
[0122]
[0123] The meaning of X in equation (3') is the same as the meaning of X in equation (3).
[0124] There is no particular limitation on the proportion of structural unit B' in the polymer. In some preferred embodiments, the proportion of structural unit B' is preferably 20 mol% or less, more preferably 10 mol% or less, and even more preferably 2 mol% or less, relative to all units of the hydrophilic polymer with blocked isocyanate groups.
[0125] From the viewpoint of imparting superior hydrophilicity, in some preferred embodiments, the hydrophilic polymer with blocked isocyanate groups is virtually free of structural unit B'. Here, "virtually free" means that the proportion of structural unit B' is 0 mol% relative to all units of the hydrophilic polymer with blocked isocyanate groups, unless structural unit B' is present as an unavoidable impurity component.
[0126] In some particularly preferred embodiments, from the viewpoint of more readily obtaining the hydrophilic polymer with blocked isocyanate groups of the present invention, the hydrophilic polymer with blocked isocyanate groups of the present invention is preferably derived from a polymer precursor having structural unit A' and structural unit B'.
[0127] In this invention, there are no particular restrictions on the molecular chain structure of the polymer precursor, but from the viewpoint of more easily obtaining the hydrophilic polymer with blocked isocyanate groups of the present invention, the polymer precursor is preferably an alternating copolymer or a random copolymer.
[0128] In this invention, there is no particular limitation on the number-average molecular weight of the polymer precursor, which can be appropriately adjusted according to actual needs. For example, it can be 2000-50000 g / mol, or 4000-30000 g / mol, or 5000-25000 g / mol.
[0129] In some more preferred embodiments, the ratio of structural unit A' to all structural units of the polymer precursor is more preferably 20-80 mol%, more preferably 30-70 mol%, and particularly preferably 40-60 mol%.
[0130] In some other, more preferred embodiments, the ratio of structural unit B' to all structural units of the polymer precursor is more preferably 20–60 mol%, more preferably 30–50 mol%, and particularly preferably 30–40 mol%.
[0131] <Structural Unit C>
[0132] The hydrophilic polymer with a blocked isocyanate group of the present invention may also have a structural unit C based on an electron-rich monomer having a carbon-carbon double bond.
[0133] Examples of electron-rich monomers include, but are not limited to: styrene-based monomers such as styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, ethylstyrene, 3,4-dimethylstyrene, and tert-butylstyrene; indene-based monomers such as indene and oxyindene; vinyl carboxylic acid esters such as vinyl acetate, vinyl propionate, and vinyl butyrate; α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, and 1-heptene; allyl ether-based monomers such as methyl allyl ether, ethyl allyl ether, phenyl allyl ether, and butyl allyl ether; vinyl ether olefin monomers such as methyl vinyl ether, ethyl vinyl ether, phenyl vinyl ether, and butyl vinyl ether; and organic matrix monomers such as furfural, furfurylamine, furfuryl alcohol, and furoic acid. These electron-rich monomers can be used alone or in combination of two or more.
[0134] In some specific embodiments, the ratio of structural unit C to all structural units of the hydrophilic polymer with blocked isocyanate groups is preferably 50 mol% or less, more preferably 30 mol% or less.
[0135] In some preferred embodiments, the molar ratio of the total of structural unit A and structural unit B (and, if present, structural unit A' and structural unit B') to structural unit C is preferably between 1 / 2 and 2 / 1, more preferably between 1 / 1 and 1.5 / 1.
[0136] In some particularly preferred embodiments, when the hydrophilic polymer of the present invention with blocked isocyanate groups is preferably derived from a polymer precursor having structural units A' and B', the polymer precursor also has structural unit C from the viewpoint that it is easier to obtain the polymer precursor and easier to adjust the properties of the hydrophilic polymer with blocked isocyanate groups.
[0137] <Other structural unit D>
[0138] Without impairing the technical effects of the present invention, in addition to structural unit A, structural unit B, structural unit A', structural unit B', and structural unit C, the hydrophilic polymer with blocked isocyanate groups may optionally have other structural units.
[0139] In this invention, other structural units D can be structural units based on other monomers known in the art (preferably, other monomers capable of participating in free radical polymerization), such as electron-deficient monomers other than the source monomers of structural units A, B, A', and B'.
[0140] In some particularly preferred embodiments, when the hydrophilic polymer of the present invention with blocked isocyanate groups is preferably derived from a polymer precursor having structural units A' and B', the polymer precursor also has other structural units D.
[0141] <<Method for manufacturing hydrophilic polymers with blocked isocyanate groups>>
[0142] The method for manufacturing the hydrophilic polymer with blocked isocyanate groups of the present invention includes the following steps:
[0143] (a) A polymer precursor having structural unit A' and structural unit B' as shown in formula (3'), wherein structural unit A' is at least one structural unit selected from the units shown in formula (1') and formula (2'):
[0144]
[0145] (b) Reacting a diisocyanate compound with a capping agent to obtain a blocked isocyanate intermediate;
[0146] (c) Reacting the closed isocyanate intermediate with the structural unit A' to form structural unit A.
[0147] The structural unit A is at least one structural unit selected from the units shown in equation (1) and equation (2):
[0148]
[0149] In formulas (1'), (2'), (1), and (2), R1 is a hydrogen atom or a methyl group, R2, R3, and R4 independently represent a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, or an aryl group with 6 to 12 carbon atoms, respectively, Q represents an organic group with a capped isocyanate group, and n is 1 or 2; however, in formula (1'), one of the two R2s is a hydrogen atom;
[0150] (d) Hydrolyzing or reacting the structural unit B' with at least one selected from ammonia and alkali metal hydroxides to form the structural unit B shown in formula (3):
[0151]
[0152] In formulas (3') and (3), X represents a tetravalent organic group, Y represents an amino group or -OI, and each I independently represents a hydrogen atom, an ammonium group or an alkali metal.
[0153] In this case, there is no ineffective consumption of isocyanate groups during the manufacturing process, the utilization rate of isocyanate groups is high during preparation, and it is easy to obtain hydrophilic groups and more active isocyanate groups. Moreover, the amount of these functional groups can be widely adjusted. The hydrophilic polymer with blocked isocyanate groups has excellent processability when preparing polyurethane materials, and is therefore suitable for industrial production and application.
[0154] In this invention, the numbering of the above steps does not necessarily mean that these steps are performed in a specific order. For example, they can be performed in the order of (a), (b), (c), (d), or in the order of (a), (b), (d), (c), or in the order of (b), (a), (c), (d), or in the order of (b), (a), (d), (c). In some preferred embodiments, they are performed in the order of (a), (b), (c), (d).
[0155] In some preferred embodiments, the hydrophilic polymer with blocked isocyanate groups obtained by the manufacturing method of the present invention has five or more structural units A in one molecular chain; in other preferred embodiments, the proportion of structural units A in the hydrophilic polymer with blocked isocyanate groups obtained by the manufacturing method of the present invention is 7 × 10⁻⁶ relative to the total mass of the hydrophilic polymer with blocked isocyanate groups. -4 Above mol / g.
[0156] Other preferred embodiments of the hydrophilic polymer with blocked isocyanate groups obtained by the manufacturing method of the present invention are as described above in <<Hydrophilic Polymer with Blocked Isocyanate Groups>>.
[0157] The steps will be described in detail below.
[0158] <Step (a)>
[0159] In step (a), a polymer precursor having structural unit A' and structural unit B' as shown in formula (3') was prepared. Structural unit A' is at least one structural unit selected from the units shown in formula (1') and formula (2').
[0160]
[0161] In formulas (1') and (2'), R1 is a hydrogen atom or a methyl group, and R2, R3, and R4 independently represent a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, or an aryl group with 6 to 12 carbon atoms, respectively; however, in formula (1'), one of the two R2 groups is a hydrogen atom. The details and preferred embodiments of these groups are the same as those in formulas (1') and (2') in <<Hydrophilic Polymers with Blocked Isocyanate Groups>>.
[0162]
[0163] In formula (3'), X represents a tetravalent organic group. The details and preferred embodiments of this group are the same as those in formula (3') in <<Hydrophilic Polymers with Blocked Isocyanate Groups>>.
[0164] In this invention, there is no particular limitation on the number-average molecular weight of the polymer precursor, which can be appropriately adjusted according to actual needs. For example, it can be 2000-50000 g / mol, or 4000-30000 g / mol, or 5000-25000 g / mol.
[0165] In this invention, the unit represented by formula (1') which can be used as structural unit A' is derived from the corresponding (meth)acrylamide monomer; the unit represented by formula (2') which can be used as structural unit A' is derived from the corresponding maleimide monomer; and the structural unit B' is derived from the corresponding unsaturated dicarboxylic anhydride monomer.
[0166] In some preferred embodiments, from the viewpoint of more easily obtaining hydrophilic polymers with blocked isocyanate groups, the polymer precursor is obtained based on free radical polymerization. Furthermore, there are no particular limitations on the polymerization method; various methods known in the art can be used. For example, solution polymerization or precipitation polymerization methods are preferred.
[0167] As a non-limiting example, a specific manufacturing method may be as follows: various monomers ((meth)acrylamide monomers and / or maleimide monomers, unsaturated dicarboxylic anhydride monomers (both of which are electron-deficient monomers), optional electron-rich monomers, optional other monomers), and a free radical initiator are dissolved in a solvent such that the total mass percentage concentration of all monomers is set to 2-40%, more preferably 5-40%, and even more preferably 10-30% from the viewpoint of a more suitable molecular weight of the polymer precursor, and the initiator concentration is set to 0.05-5% by mass, more preferably 0.5-3% by mass, and even more preferably 1-2.5% by mass; then the polymerization reaction is carried out by heating (since the half-life of different types of initiators varies at different temperatures, the reaction temperature and time should be adjusted according to the selected initiator, without particular limitation, for example, the reaction temperature is 50-120°C, such as 60-100°C, 60-90°C, and the reaction time is 1-24 hours, such as 1-10 hours). After polymerization, the obtained polymer microspheres are separated by centrifugation and / or filtration, washed (using solvents such as petroleum ether; nonpolar alkane solvents, such as n-pentane, n-hexane, cyclohexane, n-heptane, n-octane, isooctane, n-nonane, n-decane, undecane, dodecane; methyl tert-butyl ether; alcohol solvents, such as methanol, ethanol, isopropanol. There is no limit to the number of washes), and dried (using various drying methods known in the art) to obtain the polymer precursor of the present invention.
[0168] When electron-rich monomers are used, the molar ratio of the total (meth)acrylamide monomers and / or maleimide monomers and unsaturated dicarboxylic anhydride monomers to electron-rich monomers is preferably 1 / 2 to 2 / 1, more preferably 1 / 1 to 1.5 / 1.
[0169] The free radical initiator is a conventional free radical initiator, which can be an azo initiator or a peroxide free radical initiator. Azo initiators include: azobisisobutyronitrile, azobisisoheptanenitrile, azobisisobutyramidine hydrochloride, azobisisobutyramidazole hydrochloride, azobiscyanopentanoic acid, azobisisopropylimidazoline, etc.; peroxide initiators include: benzoyl peroxide, di(2,4-dichlorobenzoyl peroxide), di-tert-butyl peroxide, dodecyl peroxide, tert-butyl peroxynivalate, tert-butyl peroxynivalate, tert-butyl peroxynivalate, tert-butyl peroxynivalate, tert-pentyl peroxynivalate, tert-butyl peroxynivalate, di-sec-butyl peroxynivalate, di(hexadecyl)dicarbonate peroxide, diisopropyl peroxynivalate, dicyclohexyl peroxynivalate, dicumyl peroxide, di-tert-butyl peroxide, and di-tert-pentyl peroxide, etc. These initiators can be used alone or in combination of two or more. Preferred initiators are azobisisobutyronitrile, azobisisobutyronitrile, and benzoyl peroxide, with azobisisobutyronitrile being more preferred.
[0170] When using solution polymerization, examples of solvents include, but are not limited to, ketone solvents such as acetone, butanone, methyl acetone, 2-pentanone, 3-pentanone, 3-methyl-2-butanone, 2-hexanone, 3-hexanone, 2-methyl-3-pentanone, 3,3-dimethyl-2-butanone, 4-methyl-2-pentanone, 2-heptanone, 3-heptanone, 4-heptanone, 2,4-dimethyl-3-pentanone, 2-octanone, 2,6-dimethyl-4-heptanone, cyclopentanone, cyclohexanone, and cycloheptanone; ether solvents such as tetrahydrofuran and dioxane; amide solvents such as dimethylformamide and dimethylacetamide; pyrrolidone solvents such as N-methylpyrrolidone; and sulfoxide solvents such as dimethyl sulfoxide. These solvents can be used alone or in combination of two or more.
[0171] When precipitation polymerization (e.g., self-stabilizing precipitation polymerization) is used, the solvent can be a single solvent or a mixture of solvents. During the polymerization reaction, polymers that cannot be dissolved in the solvent form polymer microspheres. Therefore, as the reaction proceeds, the polymer precipitates from the solvent. Furthermore, in the case of self-stabilizing precipitation polymerization, no surfactant is added to the polymerization reaction.
[0172] In some preferred embodiments, the single solvent is preferably an organic acid ester solvent.
[0173] In some other preferred embodiments, the mixed solvent is preferably a combination of at least one selected from organic acid ester solvents, aromatic hydrocarbon solvents, ketone solvents, and an alkane solvent. In some preferred embodiments, the volume ratio of the organic acid ester solvent (at least one selected from organic acid ester solvents, aromatic hydrocarbon solvents, ketone solvents) to the alkane solvent in the mixed solvent is preferably 1:3 to 3:1, more preferably 1.5:1 to 1:1.5.
[0174] Examples of organic acid ester solvents include, but are not limited to: ethyl formate, amyl formate, ethyl acetate, butyl acetate, benzyl acetate, isoamyl acetate, phenyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, ethyl benzoate, butyl benzoate, ethyl phenylacetate, butyl phenylacetate, etc.
[0175] Examples of aromatic hydrocarbon solvents include, but are not limited to: toluene, ethylbenzene, xylene, etc.
[0176] Examples of ketone solvents are as described above.
[0177] The alkane solvent can be alkanes with 4-12 carbon atoms, including but not limited to: n-pentane, n-hexane, cyclohexane, n-heptane, n-octane, isooctane, n-nonane, n-decane, undecane, dodecane, etc.
[0178] In some more preferred embodiments, the mixed solvent is preferably isoamyl acetate and n-heptane, isoamyl acetate and n-hexane, butanone and n-heptane, butanone and n-hexane, ethyl acetate and n-heptane, or ethyl benzoate and n-heptane.
[0179] <Step (b)>
[0180] In step (b), the diisocyanate compound is reacted with a capping agent to obtain a blocked isocyanate intermediate. The blocked isocyanate intermediate of the present invention is a blocked isocyanate intermediate containing only one active isocyanate group.
[0181] In this invention, there is no particular limitation on the specific types of diisocyanate compounds, and they can be various diisocyanate compounds known in the art. In some preferred embodiments, from the viewpoint of more easily obtaining the hydrophilic polymer with blocked isocyanate groups of the present invention, the diisocyanate compound is preferably selected from at least one of isophorone diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, trimethylhexamethylene diisocyanate, dicyclohexylmethane diisocyanate, or phenylenediamine diisocyanate.
[0182] In this invention, there is no particular limitation on the specific type of capping agent, and it can be any type of capping agent known in the art, such as alcohols, phenols, oximes, amines, amides, imides, active methylene compounds, imidazoles, pyrazoles, triazoles, bisulfites, etc. In some preferred embodiments, the capping agent is selected from at least one of phenol, 2-pyridinephenol, 1,2-propanediol, 2-ethylhexanol, ethylene glycol ethyl ether, ethylene glycol butyl ether, diethylene glycol butyl ether, ε-caprolactam (ε-CAP), methyl ethyl ketone oxime, 3,5-dimethylpyrazole, triazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, diisopropylamine, diethyl malonate, maleimide, and succinimide.
[0183] In other preferred embodiments, from the viewpoint of obtaining the blocked isocyanate intermediate of the present invention more efficiently and reducing costs, the molar ratio of the diisocyanate compound to the capping agent is preferably 0.8 / 1 to 1.2 / 1, more preferably 0.9 / 1 to 1.1 / 1.
[0184] As a non-limiting example, a specific manufacturing method may be as follows: a diisocyanate compound (e.g., formula (I) in reaction (A) below) is reacted with a blocking agent (e.g., BL-H in reaction (A) below) to prepare a blocked isocyanate intermediate (e.g., formula (II) in reaction (A) below). In reaction (A), U in formula (I) is an alkylene group, and BL in formula (II) is a capping group.
[0185]
[0186] <Step (c)>
[0187] In step (c), the closed isocyanate intermediate obtained in step (b) is reacted with structural unit A' to form structural unit A.
[0188] Structural unit A is at least one structural unit selected from the units shown in equation (1) and equation (2):
[0189]
[0190] In formulas (1) and (2), Q represents an organic group with a capped isocyanate group, and n is 1 or 2; wherein the details and preferred schemes of Q and n are the same as those in formulas (1) and (2) in <<Hydrophilic Polymers with Capped Isocyanate Groups>>.
[0191] In some preferred embodiments, the molar ratio of the blocked isocyanate intermediate to structural unit A' is preferably 0.2 / 1 to 1.2 / 1, more preferably 0.5 / 1 to 1.1 / 1, and even more preferably 0.6 / 1 to 1.0 / 1. In this case, the reversible decomposition of the blocked isocyanate intermediate during the reaction process and the potential crosslinking reaction between the generated diisocyanate and the active hydrogen groups in the copolymer side groups are further suppressed, and the utilization efficiency of the blocked isocyanate intermediate is improved.
[0192] In other preferred embodiments, 15 mol% or more, more preferably 30 mol% or more, further preferably 50 mol% or more, and particularly preferably 70 mol% or more of all structural units A' of the polymer precursor are formed as structural unit A.
[0193] In step (c), structural unit A' can be derived from the polymer precursor obtained in step (a) or from the polymer that forms structural unit B obtained in step (d). Hereinafter, both polymers will be collectively referred to as "polymers having structural unit A'". That is, in step (c), the blocked isocyanate intermediate obtained in step (b) is reacted with either the polymer precursor obtained in step (a) or the polymer that forms structural unit B obtained in step (d). In some preferred embodiments, the blocked isocyanate intermediate obtained in step (b) is reacted with the polymer precursor obtained in step (a).
[0194] As a non-limiting example, a specific manufacturing method may be as follows: a polymer having structural unit A' (preferably, the polymer precursor obtained in step (a)) is dissolved in a suitable solvent, a blocked isocyanate intermediate (e.g., as shown in formula (II) in reactions (A) and (B)) is added, the mixture is homogeneous, and a reaction is carried out to introduce the blocked isocyanate group into the polymer by means of a urethane bond to obtain a polymer forming structural unit A (e.g., as shown in formula (III) in reaction (B)); after the reaction is completed, the reaction product is precipitated with a precipitant, separated, and dried.
[0195]
[0196] Examples of solvents used in the reaction include, but are not limited to: ketone solvents such as acetone, butanone, methyl acetone, 2-pentanone, 3-pentanone, 3-methyl-2-butanone, 2-hexanone, 3-hexanone, 2-methyl-3-pentanone, 3,3-dimethyl-2-butanone, 4-methyl-2-pentanone, 2-heptanone, 3-heptanone, 4-heptanone, 2,4-dimethyl-3-pentanone, 2-octanone, 2,6-dimethyl-4-heptanone, cyclopentanone, cyclohexanone, cycloheptanone, etc.; ether solvents such as tetrahydrofuran and dioxane; amide solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; sulfoxide solvents such as dimethyl sulfoxide; and pyrrolidone solvents such as N-methylpyrrolidone. These solvents can be used alone or in combination of two or more.
[0197] To make the reaction of structural unit A' in the polymer chain more uniform and to further suppress the crosslinking reaction between copolymer chains in the system, the mass percentage concentration of the polymer having structural unit A' (e.g., the polymer precursor obtained in step (a)) relative to the total mass of the reaction system is preferably 1 to 15% by mass, more preferably 2.5 to 10% by mass, and even more preferably 5 to 7.5% by mass.
[0198] Examples of precipitants include, but are not limited to: petroleum ether; alkane solvents, such as n-pentane, n-hexane, cyclohexane, n-heptane, n-octane, isooctane, n-nonane, n-decane, undecane, and dodecane; methyl tert-butyl ether; alcohol solvents, such as methanol, ethanol, and isopropanol; etc. These precipitants can be used alone or in combination of two or more.
[0199] <Step (d)>
[0200] In step (d), structural unit B' is hydrolyzed or reacted with at least one selected from ammonia and alkali metal hydroxides to form structural unit B as shown in formula (3):
[0201]
[0202] In formula (3), X represents a tetravalent organic group, Y represents an amino group or -OI, and each I independently represents a hydrogen atom, an ammonium group, or an alkali metal. The details and preferred embodiments of X and I are the same as those in formula (3) in <<Hydrophilic Polymers with Blocked Isocyanate Groups>>.
[0203] In some preferred embodiments, 70 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more of all structural units B' of the polymer precursor are formed as structural unit B.
[0204] In this invention, there are no particular restrictions on the form in which ammonia is used; it can be ammonia gas or ammonia water. When ammonia gas is used, it can form the structural unit B in formula (3), where Y represents an amino group.
[0205] In this invention, examples of alkali metal hydroxides include, but are not limited to, sodium hydroxide, potassium hydroxide, etc.
[0206] In step (d), structural unit B' can be derived from the polymer precursor obtained in step (a) or from the polymer that forms structural unit B obtained in step (c). Hereinafter, both polymers will be collectively referred to as "polymers having structural unit B'". That is, in step (d), either the polymer precursor obtained in step (a) or the polymer that forms structural unit A obtained in step (c) is reacted. In some preferred embodiments, the polymer that forms structural unit A obtained in step (c) is reacted.
[0207] As a non-limiting example, a specific manufacturing method may be as follows: dissolving a polymer having structural unit B' (preferably, the polymer that forms structural unit A obtained in step (c), for example, formula (III) in reaction (B)) in a suitable solvent and hydrolyzing it, or reacting it with at least one selected from ammonia and alkali metal hydroxides, thereby further converting the anhydride group into a hydrophilic carboxylic acid or carboxylate group to obtain a polymer that forms structural unit B (for example, formula (IV) in reaction (B)).
[0208] <<Polyurethane Materials>>
[0209] The polyurethane materials of the present invention are formed using the <<hydrophilic polymer with blocked isocyanate groups>> described in the present invention or hydrophilic polymers with blocked isocyanate groups obtained by <<method of manufacturing hydrophilic polymers with blocked isocyanate groups>>. Specifically, these hydrophilic polymers with blocked isocyanate groups are used as polyisocyanates in the polyurethane forming material.
[0210] Furthermore, the polyurethane-based materials of the present invention are not limited to materials formed by mixing and curing these hydrophilic polymers with blocked isocyanate groups with other hydroxyl-containing resins / compounds. They can also be materials formed by contacting and curing these hydrophilic polymers with blocked isocyanate groups with a hydroxyl-rich substrate (glass, paper, or other treated surfaces, etc.).
[0211] <<Example>>
[0212] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.
[0213] <Example 1>
[0214] (a) Preparation of maleimide / maleic anhydride / styrene terpolymer (polymer precursor)
[0215] First, under stirring conditions, 2.91 g of maleimide (0.03 mol), 6.86 g of maleic anhydride (0.07 mol), and 10.4 g of styrene (0.10 mol) were dissolved and dispersed in 180 mL of xylene. 0.202 g of azobisisobutyronitrile initiator (1 wt% relative to the total monomer mass) was added, and the mixture was stirred to dissolve and form a homogeneous reaction system. Second, after purging the reaction system with nitrogen for 10 minutes to remove oxygen, it was placed in a 75°C oil bath for a constant temperature reaction for 6 hours to form a maleimide / maleic anhydride / styrene terpolymer. After the reaction, a solid-liquid dispersion of the maleimide / maleic anhydride / styrene terpolymer was obtained. After separation, washing, and drying, the yield of the maleimide / maleic anhydride / styrene terpolymer was 95%.
[0216] The number average molecular weight of the maleimide / maleic anhydride / styrene terpolymer is 10000 g / mol.
[0217] (b) Preparation of blocked isocyanate intermediates
[0218] Under stirring conditions, 0.169 g caprolactam (1.5 mmol) and 0.252 g hexamethylene isocyanate (1.5 mmol) were dispersed in 5 mL of acetone, and 0.5% dibutyltin dilaurate catalyst was added. The mixture was reacted at 60 °C for 3 h to prepare a caprolactam-terminated hexamethylene isocyanate intermediate.
[0219] (c) Structural unit A' (a maleimide-based unit) is formed as structural unit A
[0220] 1.0 g of the maleimide / maleic anhydride / styrene terpolymer prepared in (a) above was dissolved in 10 mL of acetone. After complete dissolution, the caprolactam-terminated hexamethylene isocyanate intermediate prepared in (b) above was added dropwise to the maleimide / maleic anhydride / styrene terpolymer solution at 60 °C. The addition was completed within 30 minutes, and the reaction was continued for 6 h. After precipitation, separation, washing, and drying, the polymer-based blocked isocyanate was obtained (the polymer forming structural unit A, of which 90 mol% of all maleimide-based units formed structural unit A, i.e., connected with blocked isocyanate groups).
[0221] (d) Structural unit B' (a unit based on maleic anhydride) is formed as structural unit B
[0222] The polymer-based blocked isocyanate prepared in (c) above is redissolved in acetone, and an appropriate amount of ammonia is added to adjust the pH value to about 9-10 so that all structural units B' are formed into structural units B, thus obtaining a hydrophilic polymer with blocked isocyanate groups.
[0223] After conversion, the proportion of structural unit A relative to the total mass of the hydrophilic polymer with blocked isocyanate groups is 1.05 × 10⁻⁶. -3 mol / g, the proportion of structural unit B is 2.5 × 10 -3 mol / g. In hydrophilic polymers with blocked isocyanate groups, there are 14 structural units A in one molecular chain.
[0224] The utilization rate of isocyanate was 99.2%. The utilization rate of isocyanate was calculated by the following formula: the molar content of active isocyanate groups in the hydrophilic polymer with blocked isocyanate groups determined by di-n-butylamine titration / the molar amount of blocked isocyanate intermediates used in (c).
[0225] (e) Preparation of polyurethane materials
[0226] Component 1 is a hydroxyl-containing polyacrylate dispersion (polymerized from acrylic acid, hydroxyethyl methacrylate, methyl methacrylate and butyl acrylate monomers, with a solid content of 60%), and component 2 is the hydrophilic polymer aqueous dispersion with blocked isocyanate groups prepared above (d) (with a solid content of 40%).
[0227] 100 parts of component 1 and 50 parts of component 2 were mixed and stirred evenly to obtain a waterborne polyurethane coating product. Using cold-rolled steel sheet as a substrate, the prepared waterborne polyurethane coating product was applied to its surface, maintaining a film thickness of 40±3 μm. The coating was then baked at 120℃ for 30 min to obtain a cured coating. The prepared coating is smooth and even, has good gloss, and exhibits excellent resistance to methyl ethyl ketone (MEK) wiping.
[0228] The methyl ethyl ketone (MEK) resistance to wiping is evaluated as follows: A soft cloth soaked in MEK is used to wipe the coating back and forth 1000 times. The surface defects are then observed using an optical microscope. If no defects are found, the coating has a high degree of cross-linking and is rated "excellent." If defects (such as pinholes or gaps) appear, the coating has a low degree of cross-linking and is rated "poor."
[0229] <Example 2>
[0230] Except for the preparation of polymer precursors using only maleimide and maleic anhydride (0.06 mol maleimide and 0.14 mol maleic anhydride), a blocked isocyanate polymer was obtained in a similar manner to that in Example 1, and polyurethane-based materials were prepared.
[0231] The number-average molecular weight of the maleimide / maleic anhydride copolymer is 9000 g / mol.
[0232] In this copolymer, 90 mol% of all maleimide-based units are formed as structural unit A. All maleic anhydride-based units are formed as structural unit B.
[0233] After conversion, the proportion of structural unit A relative to the total mass of the hydrophilic polymer with blocked isocyanate groups is 1.6 × 10⁻⁶. -3 mol / g, the proportion of structural unit B is 3.8 × 10 -3 mol / g. In hydrophilic polymers with blocked isocyanate groups, there are 28 structural units A in one molecular chain.
[0234] The utilization rate of isocyanate is 99.8%.
[0235] In addition, the prepared coating is smooth and even, has a good gloss, and exhibits excellent resistance to methyl ethyl ketone (MEK) wiping.
[0236] <Example 3>
[0237] Except for replacing maleimide with acrylamide, a blocked isocyanate polymer was obtained using a method similar to that in Example 1, and a polyurethane-based material was prepared.
[0238] The number-average molecular weight of the acrylamide / maleic anhydride / styrene terpolymer is 9700 g / mol.
[0239] In this copolymer, 85 mol% of all acrylamide-based units are formed as structural unit A. All maleic anhydride-based units are formed as structural unit B.
[0240] After conversion, relative to the total mass of the hydrophilic polymer with blocked isocyanate groups, the proportion of structural unit A is 9 × 10⁻⁶. -4 mol / g, the proportion of structural unit B is 2.5 × 10 -3 mol / g. In hydrophilic polymers with blocked isocyanate groups, there are 13 structural units A in one molecular chain.
[0241] The utilization rate of isocyanate is 99.5%.
[0242] In addition, the prepared coating is smooth and has a good gloss, and excellent resistance to methyl ethyl ketone (MEK) wiping.
[0243] <Comparative Example 1>
[0244] Except for changing the amount of caprolactam-terminated hexamethylene isocyanate intermediate in (c), a polymer with blocked isocyanate groups was obtained in a manner similar to that in Example 1, and a polyurethane-based material was prepared.
[0245] In this copolymer, 50 mol% of all maleimide-based units are formed as structural unit A. All maleic anhydride-based units are formed as structural unit B.
[0246] After conversion, the proportion of structural unit A relative to the total mass of the hydrophilic polymer with blocked isocyanate groups is 5.5 × 10⁻⁶. -4 mol / g, the proportion of structural unit B is 2.5 × 10 -3 mol / g. In hydrophilic polymers with blocked isocyanate groups, one molecular chain has 7 structural units A.
[0247] The utilization rate of isocyanate was 99.1%.
[0248] In addition, the prepared coating is smooth and has a good gloss, but its resistance to methyl ethyl ketone (MEK) wiping is poor.
[0249] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.
[0250] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or technological improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.
Claims
1. A hydrophilic polymer with blocked isocyanate groups, characterized in that, The hydrophilic polymer with blocked isocyanate groups has structural unit A and structural unit B as shown in formula (3). The structural unit A is at least one structural unit selected from the units shown in equation (1) and equation (2): Equation (1) Equation (2) In formulas (1) and (2), R1 is a hydrogen atom or a methyl group, R2, R3, and R4 independently represent a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, or an aryl group with 6 to 12 carbon atoms, respectively, Q represents an organic group with a capped isocyanate group, and n is 1 or 2. Equation (3) In equation (3), X represents at least one group selected from the groups shown in formula (x1) and formula (x2): Equation (x1) Equation (x2) In formulas (x1) and (x2), R5 to R8 are each independently hydrogen or an alkyl group having 1 to 12 carbon atoms, and * indicates the position connected to the carbonyl group; Y represents amino or -OI. Each I independently represents a hydrogen atom, an ammonium group, or an alkali metal. In the hydrophilic polymer with blocked isocyanate groups, one molecular chain has more than five structural units A. The proportion of structural unit A relative to the total mass of the hydrophilic polymer with blocked isocyanate groups is 7 × 10⁻⁶. -4 mol / g or higher; the proportion of structural unit B is 4 × 10 -4 Above mol / g.
2. The hydrophilic polymer with blocked isocyanate groups according to claim 1, characterized in that, In the hydrophilic polymer with blocked isocyanate groups, one molecular chain has more than five of the structural units B.
3. The polymer according to claim 1 or 2, characterized in that, The hydrophilic polymer with blocked isocyanate groups is derived from a polymer precursor having structural unit A' and structural unit B' as shown in formula (3'): The structural unit A' is at least one structural unit selected from the units shown in equation (1') and equation (2'): Equation (1') Equation (2') The meanings of R1, R2, R3 and R4 in equations (1') and (2') are the same as those in equations (1) and (2), except that one of the two R2s is a hydrogen atom; Equation (3') The meaning of X in equation (3') is the same as the meaning of X in equation (3).
4. The hydrophilic polymer with blocked isocyanate groups according to claim 3, characterized in that, The ratio of structural unit A' to all structural units of the polymer precursor is 10–90 mol%, and the ratio of structural unit B' is 10–50 mol%.
5. The hydrophilic polymer with blocked isocyanate groups according to claim 1 or 2, characterized in that, The hydrophilic polymer with blocked isocyanate groups also has a structural unit C based on an electron-rich monomer having a carbon-carbon double bond.
6. A method for manufacturing a hydrophilic polymer with blocked isocyanate groups, characterized in that, include: (a) A polymer precursor having structural unit A' and structural unit B' as shown in formula (3'), wherein structural unit A' is at least one structural unit selected from the units shown in formula (1') and formula (2'): Equation (1') Equation (2') Equation (3'); (b) Reacting a diisocyanate compound with a capping agent to obtain a blocked isocyanate intermediate; (c) Reacting the closed isocyanate intermediate with the structural unit A' to form structural unit A. The structural unit A is at least one structural unit selected from the units shown in equation (1) and equation (2): Equation (1) Equation (2) In formulas (1'), (2'), (1), and (2), R1 is a hydrogen atom or a methyl group, R2, R3, and R4 independently represent a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, or an aryl group with 6 to 12 carbon atoms, respectively, Q represents an organic group with a capped isocyanate group, and n is 1 or 2; however, in formula (1'), one of the two R2s is a hydrogen atom; (d) Hydrolyzing or reacting the structural unit B' with at least one selected from ammonia and alkali metal hydroxides to form the structural unit B shown in formula (3): Equation (3) In equations (3') and (3), X represents at least one group selected from the groups shown in formula (x1) and formula (x2): Equation (x1) Equation (x2) In formulas (x1) and (x2), R5 to R8 are each independently hydrogen or an alkyl group having 1 to 12 carbon atoms, and * indicates the position connected to the carbonyl group; Y represents amino or -OI. Each I independently represents a hydrogen atom, an ammonium group, or an alkali metal; In the hydrophilic polymer with blocked isocyanate groups, one molecular chain has more than five structural units A. The proportion of structural unit A relative to the total mass of the hydrophilic polymer with blocked isocyanate groups is 7 × 10⁻⁶. -4 mol / g or higher; the proportion of structural unit B is 4 × 10 -4 Above mol / g.
7. The manufacturing method according to claim 6, characterized in that, In step (b), the diisocyanate compound is at least one selected from isophorone diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, trimethylhexamethylene diisocyanate, dicyclohexylmethane diisocyanate, or phenylmethylene diisocyanate; the capping agent is at least one selected from phenol, 2-pyridinephenol, 1,2-propanediol, 2-ethylhexanol, ethylene glycol ethyl ether, ethylene glycol butyl ether, diethylene glycol butyl ether, ε-caprolactam (ε-CAP), methyl ethyl ketone oxime, 3,5-dimethylpyrazole, triazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, diisopropylamine, diethyl malonate, maleimide, and succinimide. The molar ratio of the diisocyanate compound to the capping agent is 0.8 / 1 to 1.2 / 1.
8. The manufacturing method according to claim 6 or 7, characterized in that, In step (c), the molar ratio of the closed isocyanate intermediate to the structural unit A' is 0.2 / 1 to 1.2 / 1; more than 15 mol% of all structural units A' of the polymer precursor are formed as structural unit A.
9. The manufacturing method according to claim 6 or 7, characterized in that, In step (d), at least 70 mol% of all structural units B' of the polymer precursor are formed as structural unit B.
10. A polyurethane-based material, characterized in that, The polyurethane-based material is formed using a hydrophilic polymer with blocked isocyanate groups according to any one of claims 1 to 5, or a hydrophilic polymer with blocked isocyanate groups obtained by the manufacturing method according to any one of claims 6 to 9.