A powdered polycarbodiimide compound, a method for producing the same, a resin composition, and applications thereof

Abstract

The present application provides a kind of powdered polycarbodiimide compound and its preparation method, resin composition and its application, powdered polycarbodiimide compound is represented by following general formula 1: In general formula 1, R1 and R3 represent the residue of organic compound with one functional group that can be reacted with isocyanate group [-NCO], R1, R3 are same or different;R2 represents the divalent residue of diisocyanate compound removed two isocyanate groups;X1, X2 represent the group formed by the reaction of the organic compound with isocyanate, X1, X2 are same or different;N represents the integer of 3-15.

Description

Technical Field

[0001] This invention relates to the field of polycarbodiimide technology, and more specifically, to a powdered polycarbodiimide compound and a method for preparing the same, as well as resin compositions comprising the powdered polycarbodiimide compound and their applications. Background Technology

[0002] Polycarbodiimides are a class of organic compounds containing repeating carbodiimide functional groups [-N=C=N-], with the general formula [-R1-N=C=N-R2-]n, where R1 and R2 can be any of aliphatic groups, aromatic groups, or heteroatom-containing segments, and R1=R2. Due to their highly electron-deficient cumulative double bond structure, polycarbodiimides exhibit strong electrophilicity and can react with compounds containing active hydrogen atoms under certain conditions, such as carboxylic acids, amines, and alcohols. Based on this, polycarbodiimides are widely used as hydrolytic stabilizers in easily hydrolyzed materials such as polyesters and polyurethanes. In addition, polycarbodiimides possess good adhesive properties and excellent heat resistance, and have been used in various applications such as resin modifiers, crosslinking agents, and molding materials.

[0003] Currently, the most common method is to use 4,4'-diphenylmethane diisocyanate and organic monoisocyanate compounds to obtain liquid polycarbodiimide compounds through a decarbonylation reaction in the presence of a polymerization catalyst. However, due to the structure of the raw materials, the solution is prone to gelation, resulting in low storage stability.

[0004] There is also regulation and The preparation of polycarbodiimide compounds that can be mixed with thermosetting resins in appropriate proportions has enhanced storage stability to some extent and improved the thermal stability of the cured resin system, but the storage stability time still needs to be improved. However, other requirements for cured resin systems are constantly increasing, such as water absorption, dielectric properties, and coefficient of linear expansion, but this aspect is rarely mentioned.

[0005] Therefore, it is particularly important to prepare a polycarbodiimide compound with long-term storage stability and convenient transportation, as well as a resin composition containing such polycarbodiimide that has high temperature resistance, low dielectric constant, low moisture absorption and low coefficient of linear expansion. Summary of the Invention

[0006] In view of the problems existing in the background art, the purpose of this invention is to provide a polycarbodiimide compound with long-term storage stability, convenient transportation, and usability as a curing agent for thermosetting resins. This compound inhibits the low-temperature reactivity of the resin while improving the heat resistance and dielectric properties of the cured system, and reduces the moisture absorption and coefficient of linear expansion. The invention also includes a method for preparing the compound and a resin composition containing this polycarbodiimide compound. A significant advantage is that the powdered polycarbodiimide compound can be obtained directly through a polycondensation reaction and simple post-processing, facilitating subsequent processing and applications.

[0007] To achieve the above objectives, the present invention provides a powdered polycarbodiimide, represented by the following general formula 1: General Formula 1 In general formula 1, R1 and R3 represent residues of an organic compound having a functional group that can react with an isocyanate group [-NCO] removed, and R1 and R3 may be the same or different; R2 represents a diisocyanate compound having two divalent residues of isocyanate groups removed; X1 and X2 represent groups formed by the reaction of the organic compound with an isocyanate, and X1 and X2 may be the same or different; n represents an integer from 3 to 15.

[0008] Optionally, R2 represents at least one of Formula 1 and Formula 2, where Formula 1 represents a divalent residue from 1,5-naphthalene diisocyanate with two isocyanate groups removed, and Formula 2 represents a divalent residue from 4,4'-diphenylmethane diisocyanate with two isocyanate groups removed. [Chemical Formula 1] [Chemical Formula 2] .

[0009] Optionally, the organic compound having a functional group capable of reacting with an isocyanate group includes at least one of monohydric alcohols, monoamines, monocarboxylic acids, acid anhydrides, and monoisocyanates. Monohydric alcohols are preferred.

[0010] The present invention also provides a method for preparing the powdered polycarbodiimide compound as described above, characterized by comprising the following steps: Step 1: Self-precipitation polymerization In the presence of a condensation polymerization catalyst and under heating conditions, a diisocyanate compound and an organic compound having a functional group that can react with an isocyanate group undergo a carbodiimide condensation polymerization reaction in a reaction solvent and form end caps. During the polymerization process, as the degree of polymerization increases, the polycarbodiimide compound precipitates from the solvent, forming fine particles in suspension or sedimentation, resulting in a suspension containing a polycarbodiimide compound as shown in general formula 1. Step 2: Precipitation and drying The suspension obtained in step 1 is added to a poor solvent of polycarbodiimide to precipitate the precipitate, and then filtered and vacuum dried to obtain a powdered polycarbodiimide compound as shown in Formula 1.

[0011] Optionally, the molar ratio of the organic compound to the diisocyanate compound is 1:(2-8).

[0012] Optionally, the condensation polymerization catalyst is phosphacyclopentene oxide.

[0013] Optionally, the reaction solvent includes at least one of alicyclic ethers, aromatic hydrocarbons, and halogenated hydrocarbons.

[0014] Optionally, the solvent for the polycarbodiimide includes at least one of n-hexane, cyclohexane, petroleum ether, and anhydrous ethanol; the vacuum drying temperature is 30-100°C, preferably 40-80°C, and more preferably 45-60°C.

[0015] The present invention also provides a resin composition comprising a thermosetting resin and a powdered polycarbodiimide compound as described above or a powdered polycarbodiimide compound prepared by the preparation method described above.

[0016] The present invention also provides an application of the resin composition described above in electronic devices. The beneficial effects of this invention are as follows: The present invention provides a powdered polycarbodiimide compound and a thermosetting resin composition. Firstly, compared to liquid or dissolved polycarbodiimide compounds, which exhibit a fluid dynamic state, powdered polycarbodiimide is less prone to agglomeration and gelation, demonstrating excellent storage stability and significant advantages in packaging and transportation convenience. Simultaneously, as a curing agent for thermosetting resins, it not only inhibits the resin's reactivity at low temperatures but can also be directly added to the resin without solvent treatment, facilitating processing. Furthermore, the resin composition containing the powdered polycarbodiimide compound, after curing, improves the system's high-temperature resistance, reduces water absorption, optimizes dielectric properties, and lowers the coefficient of linear expansion, meeting the requirements of electrification for thermosetting resins.

[0017] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0018] The above and other objects, features, and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings. It will be obvious to those skilled in the art that other drawings can be obtained from these drawings without any inventive effort.

[0019] Figure 1 Infrared spectra of the powdered polycarbodiimide compounds prepared in Examples 1-1 to 5-1; Figure 2 The dielectric properties of the resin compositions prepared in Examples 6-1 to 6-5 and Comparative Examples 6-6 and 6-7 are shown. Figure 3 The DMA test results are for the resin compositions prepared in Examples 6-1 to 6-5 and Comparative Examples 6-6 and 6-7. Detailed Implementation

[0020] To make the technical problems, technical solutions, and beneficial effects of this invention application clearer, the following detailed description is provided in conjunction with embodiments and comparative examples. It should be understood that the specific embodiments and comparative examples described herein are only for explaining this invention application and are not intended to limit this invention application. In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be a single item or multiple items.

[0021] It should also be understood that in the various embodiments and comparative examples of this invention, the order of the above-mentioned processes does not imply the order of execution. Some or all of the steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments and comparative examples of this invention.

[0022] The terminology used in the embodiments and comparative examples of this invention is for the purpose of describing particular embodiments and comparative examples only and is not intended to be limiting of this invention. The singular forms “a,” “the,” and “the” used in the appended claims of the embodiments and comparative examples of this invention are also intended to include the plural forms unless the context clearly indicates otherwise.

[0023] The term "Tg" is an abbreviation for "glass transition temperature," which refers to the temperature at which a polymer transitions from a glassy state to a rubbery state. Tg is the lowest temperature at which molecular chain segments can move, representing a relaxation phenomenon in the amorphous portion of a polymer as it transitions from a frozen to a thawed state.

[0024] The powdered polycarbodiimide compound of the present invention, its preparation method, resin composition and its application will be described in detail below.

[0025] Powdered polycarbodiimide compounds The powdered polycarbodiimide according to the present invention is represented by the following general formula 1: General Formula 1 In general formula 1, R1 and R3 represent residues of an organic compound having a functional group that can react with an isocyanate group [-NCO] removed, and R1 and R3 may be the same or different; R2 represents a diisocyanate compound having two divalent residues of isocyanate groups removed; X1 and X2 represent groups formed by the reaction of the organic compound with an isocyanate, and X1 and X2 may be the same or different; n represents an integer from 3 to 15.

[0026] In one embodiment of the present invention, R2 represents at least one of chemical formula 1 and chemical formula 2, where chemical formula 1 represents a divalent residue from 1,5-naphthalene diisocyanate with two isocyanate groups removed, and chemical formula 2 represents a divalent residue from 4,4'-diphenylmethane diisocyanate with two isocyanate groups removed.

[0027] [Chemical Formula 1] [Chemical Formula 2] .

[0028] The organic compound having a functional group capable of reacting with an isocyanate group, hereinafter referred to as an organic compound or end-capping agent, is not particularly limited as long as it has a functional group capable of reacting with an isocyanate group. From the viewpoint of reactivity, at least one of monohydric alcohols, monoisocyanates, monoamines, monocarboxylic acids, and anhydrides is preferred. From the viewpoints of low toxicity, operational safety, precise control of the end-group structure and molecular weight of the polymer, and reduction of side reactions, monohydric alcohols are more preferred.

[0029] Examples of monohydric alcohols include, for instance, aliphatic saturated monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, 2-ethylhexanol, n-octanol, lauryl alcohol, or stearyl alcohol; aliphatic monohydric alcohols containing functional groups such as allyl alcohol, propargyl alcohol, 2-hydroxyethyl acrylate, and methyl 2-hydroxyisobutyrate; alicyclic monohydric alcohols such as cyclohexanol, menthol, and 1-adamantanol; aromatic monohydric alcohols such as benzyl alcohol, p-tert-butylphenol, and phenethyl alcohol; and monohydric alcohols containing heteroatoms such as 2,2,2-trifluoroethanol, hexafluoroisopropanol, polyethylene glycol monomethyl ether, and polypropylene glycol monomethyl ether.

[0030] Examples of monoisocyanate compounds include aliphatic monoisocyanate compounds such as methyl isocyanate, ethyl isocyanate, n-butyl isocyanate, tert-butyl isocyanate, 2-ethylhexyl isocyanate, and cyclohexyl isocyanate; aromatic isocyanate compounds such as phenyl isocyanate, p-toluene isocyanate, dimethylphenyl isocyanate, and 2,6-diisopropylphenyl isocyanate; and monoisocyanates containing functional groups or special structures such as allyl isocyanate, (3-isocyanopropyl)triethoxysilane, and perfluoroalkyl isocyanate.

[0031] Examples of monoamine compounds include aliphatic monoamine compounds such as methylamine, ethylamine, n-butylamine, tert-butylamine, 2-ethylhexylamine, cyclohexylamine, dodecylamine, and octadecylamine; monoamine compounds containing functional groups such as benzylamine, aniline, allylamine, propargylamine, and perfluorooctylamine; and secondary amine monoamine compounds such as dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, and N-methylcyclohexylamine.

[0032] Examples of monocarboxylic acid compounds include aliphatic monocarboxylic acid compounds such as formic acid, acetic acid, propionic acid, n-butyric acid, isobutyric acid, 2-ethylhexanoic acid, neodecanoic acid, lauric acid, and stearic acid, as well as monocarboxylic acid compounds containing functional groups such as acrylic acid, methacrylic acid, undecanoic acid, terebenzoic acid, and perfluorooctanoic acid.

[0033] Examples of such acid anhydride compounds include aliphatic acid anhydrides such as succinic anhydride, glutaric anhydride, and adipic anhydride; alicyclic acid anhydrides such as tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, and nadic anhydride; aromatic acid anhydrides such as phthalic anhydride, pyromellitic dianhydride, and biphenyltetracarboxylic dianhydride; and acid anhydrides containing unsaturated or functional compounds such as maleic anhydride and itaconic anhydride.

[0034] The capping agents described above can be used alone or in combination of two or more.

[0035] As the diisocyanate constituting the main chain structure of the powdered polycarbodiimide, in addition to the listed 1,5-naphthalene diisocyanate and 4,4'-diphenylmethane diisocyanate, other diisocyanate compounds may also be included without hindering the effects of the present invention. Examples include aromatic diisocyanates such as toluene diisocyanate, 3,3'-dimethyl-4,4'-biphenyl diisocyanate, 4,4'-biphenyl diisocyanate, terephthalic diisocyanate, and isophthalic diisocyanate; 4,4'-methylene bis(cyclohexyl) isocyanate, isophorone diisocyanate, and 1,3-bis(isocyanate methyl)cyclohexyl isocyanate. Alicyclic diisocyanates such as hexane, 1,4-cyclohexane diisocyanate, norbornene diisocyanate, and bis(4-isocyanate cyclohexyl)methane; aliphatic diisocyanates such as hexamethylene diisocyanate, 1,4-butane diisocyanate, 1,12-dodecane diisocyanate, 2,2,4-trimethyl-1,6-hexane diisocyanate, and lysine diisocyanate; and polycyclic, heterocyclic, or specially structured diisocyanates such as 1,8-naphthalene diisocyanate, 9,10-phenanthroline diisocyanate, 2,6-diisocyanate pyridine, 4,4'-diisocyanate diphenyl ether, and 4,4'-diisocyanate diphenyl sulfone.

[0036] The diisocyanates described above can be used alone or in combination of two or more. When using two or more diisocyanates, their molar ratio can be chosen arbitrarily.

[0037] The ratio of the capping agent to the amount of diisocyanate can vary, and the molar ratio of the capping agent to the diisocyanate can be 1:(2-8). For example, it can be 1:2 or 1:4.

[0038] In the above general formula 1, X1 and X2 represent groups formed by the reaction of the organic compound with isocyanate groups, and X1 and X2 may be the same or different. For example, when the organic compound is a monohydric alcohol, X1 and X2 are groups represented by chemical formula 3; when the organic compound is a monoisocyanate, X1 and X2 are groups represented by chemical formula 4; when the organic compound is a monoamine, X1 and X2 are groups represented by chemical formula 5; when the organic compound is a monocarboxylic acid, X1 and X2 are groups represented by chemical formula 6; when the organic compound is an anhydride, X1 and X2 are groups represented by chemical formula 7.

[0039] [Chemical Formula 3] [Chemical Formula 4] [Chemical Formula 5] [Chemical Formula 6] [Chemical Formula 7] The monohydric alcohol compounds form urethane bonds through esterification of hydroxyl groups and isocyanate groups. Thus, the powdered polycarbodiimide compound of the present invention has a urethane bond structure. By introducing this urethane bond, the compatibility of the powdered polycarbodiimide compound of the present invention with resins is improved compared to the case without the urethane bond.

[0040] In the general formula 1, n represents the degree of polymerization of the powdered polycarbodiimide compound. n is an integer from 3 to 15, preferably an integer from 3 to 10.

[0041] When n exceeds 15, the resulting powdered polycarbodiimide is unlikely to have good compatibility with thermosetting resins. Furthermore, as the number of carbodiimide groups per molecule increases, thickening easily occurs when the powdered polycarbodiimide compound is added to the thermosetting resin.

[0042] In addition, the "degree of polymerization of polycarbodiimide groups" mentioned in this specification refers to the number of carbodiimide groups generated by the condensation polymerization between the above-mentioned isocyanate compounds, expressed as the average degree of polymerization.

[0043] Self-precipitation polymerization was used to prepare a suspension containing a polycarbodiimide compound as shown in general formula 1. In the presence of a condensation polymerization catalyst and under heating conditions, 1,5-naphthalene diisocyanate and 4,4'-diphenylmethane diisocyanate, along with an organic compound having a functional group capable of reacting with an isocyanate group, undergo carbodiimide condensation polymerization in a reaction solvent, releasing carbon dioxide gas. Simultaneously, a capping agent reacts with the isocyanate group to form caps, yielding a polycarbodiimide compound as shown in Formula 1. During polymerization, due to the strong conjugation and molecular structural rigidity of the benzene and naphthalene rings contained in 1,5-naphthalene diisocyanate and 4,4'-diphenylmethane diisocyanate, the solubility of the polycarbodiimide compound decreases with increasing degree of polymerization, causing it to precipitate from the solvent, forming fine suspended or settled particles, resulting in a suspension containing the polycarbodiimide compound as shown in Formula 1.

[0044] According to the different times of adding the end-capping agent in the polymerization reaction, there are three polymerization methods: (1) First, diisocyanate compounds are subjected to carbodiimide reaction in the presence of a polymerization catalyst to obtain a polymeric carbodiimide compound with an isocyanate group at the end. Then, an organic compound with a functional group that can react with the isocyanate group is added to the polymeric carbodiimide compound with the isocyanate group at the end to carry out the end-capping reaction; (2) Diisocyanate compounds, organic compounds with a functional group that can react with the isocyanate group, and polymerization catalyst are added together to carry out the reaction. The carbodiimide polymerization reaction and the end-capping reaction are carried out together; (3) Diisocyanate is first reacted with an organic compound with a functional group that can react with the isocyanate group to carry out the end-capping reaction. Then, a polymerization catalyst is added to carry out the carbodiimide polymerization reaction.

[0045] In the synthesis method described above, from the viewpoint of controlling the degree of polymerization and molecular weight, methods (2) and (3) are preferred, and from the viewpoint of preparation efficiency, method (2) is more preferred.

[0046] The catalyst used in the preparation reaction of the polycarbodiimide compound can be phosphacyclopentene oxide, and organophosphorus catalysts can efficiently catalyze the carbodiimide polycondensation reaction of diisocyanates. Examples of phosphacyclopentene oxides include 1-phenyl-2-phosphacyclopentene-1-oxide, 3-methyl-1-phenyl-2-phosphacyclopentene-1-oxide, 1-ethyl-2-phosphacyclopentene-1-oxide, 3-methyl-2-phosphacyclopentene-1-oxide, and their 3-phosphacyclopentene isomers. From the viewpoint of reactivity, 3-methyl-1-phenyl-2-phosphacyclopentene-1-oxide is preferred.

[0047] The amount of catalyst used is typically 0.01-5.0 parts by mass relative to 100 parts by mass of the diisocyanate compound, and more preferably 0.05-2 parts by mass.

[0048] The polymerization reaction of the polycarbodiimide compound must be carried out in a solvent environment. Examples of suitable solvents include alicyclic ethers such as tetrahydrofuran, 1,3-dioxane, and dioxolane; aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; halogenated hydrocarbons such as chlorobenzene, dichlorobenzene, trichlorobenzene, perchloroethylene, trichloroethane, and dichloroethane; and cyclohexanone, N,N-dimethylformamide, and dimethyl sulfoxide. These solvents can be used individually or in combination of two or more. For better homogeneity and control of the reaction process, a highly polar solvent is preferred.

[0049] The amount of solvent used in the polymerization reaction is typically 200-1000 parts by mass relative to 100 parts by mass of the diisocyanate compound, further optimized to 300-800 parts by mass, and even more optimized to 400-600 parts by mass.

[0050] The polymerization temperature can be adjusted appropriately according to the polymerization rate and degree of polymerization. Typically, the reaction temperature for condensation polymerization is 60-150℃, preferably 80-120℃, and more preferably 85-100℃. For example, it can be 60℃-70℃, 70℃-80℃, 80℃-90℃, 90℃-100℃, 100℃-110℃, 110℃-120℃, 120℃-130℃, 130℃-140℃, 140℃-150℃, etc. The polymerization is carried out in a solvent, and the temperature is typically within the range of 40℃ to the boiling point of the solvent. Based on the optimal temperature, N,N-dimethylformamide (DMF) is selected as the best polymerization solvent.

[0051] The reaction time for polymerizing the carbodiimide compound can be adjusted according to the reaction temperature. The reaction time is usually 2-30 hours, preferably 2-20 hours, and more preferably 4-12 hours. For example, it can be 2-4 hours, 4-6 hours, 6-8 hours, 8-10 hours, 10-14 hours, 14-18 hours, 18-22 hours, 22-26 hours, or 26-30 hours.

[0052] Meanwhile, considering that the carbodiimide group is prone to side reactions with oxygen and moisture in the air, the reaction atmosphere of the polymerization reaction should be an inert gas, usually nitrogen, argon, helium, etc. From an economic point of view, nitrogen is preferred.

[0053] Considering factors such as reaction selectivity, control of polymerization molecular weight structure, reaction temperature and time, the above-mentioned end-capping agent is preferably a monohydric alcohol compound. Based on the reaction temperature, monohydric alcohols with slightly higher boiling points are preferred, such as isobutanol, hexanol, benzyl alcohol, phenethyl alcohol, etc.

[0054] Precipitation and drying processes were performed to prepare powdered polycarbodiimide compounds. The suspension containing the polycarbodiimide compound as shown in Formula 1 obtained above is slowly added to a large amount of a low-polarity or poor-quality solvent containing polycarbodiimide to precipitate the compound. After filtration and vacuum drying, a powdered polycarbodiimide compound is obtained. The precipitation method using a poor-quality solvent of this invention can also precipitate small amounts of polycarbodiimide compound dissolved in the solution, thereby increasing the yield.

[0055] Based on the differences in solubility of polycarbodiimide in different solvents, the powdered polycarbodiimide compound is precipitated using a large amount of low-polarity or poorly polar solvents containing polycarbodiimide. The precipitation solvents used include at least one selected from n-hexane, cyclohexane, petroleum ether, and anhydrous ethanol. For economic and ease of subsequent processing, anhydrous ethanol is preferred. Multiple solvents can also be used in combination, and the mixing ratio is not particularly limited.

[0056] As a solvent for the above-mentioned precipitated polymer, the amount used is typically 10 to 50 times that of the solution containing polycarbodiimide, preferably 15 to 30 times, and more preferably 20 to 30 times.

[0057] The above precipitate was used to obtain a suspension of polycarbodiimide compound. After filtration, a powdered polycarbodiimide compound with a small amount of residual solvent was obtained. The powder was then placed in a vacuum oven to dry.

[0058] For the vacuum oven used to dry powdered polycarbodiimide, the vacuum drying temperature is typically 30-100℃, preferably 40-80℃, and more preferably 45-60℃. For example, it can be 40℃-50℃, 50℃-60℃, 60℃-70℃, 70℃-80℃, 80℃-90℃, or 90℃-100℃.

[0059] The drying time for the aforementioned vacuum oven is typically 12-48 hours, preferably 24-48 hours. For example, it can be 12-15 hours, 15-18 hours, 18-21 hours, 21-24 hours, 24-27 hours, 27-30 hours, 30-35 hours, 35-40 hours, 40-45 hours, or 45-48 hours.

[0060] The powdered polycarbodiimide compound obtained through the above method does not exhibit powder-to-powder adhesion at room temperature. Compared to liquid or dissolved polycarbodiimide compounds, the powdered polycarbodiimide compound demonstrates excellent storage stability and offers significant advantages in terms of packaging and transportation convenience. Furthermore, under controlled polymerization conditions, the powdered polycarbodiimide compound can be directly mixed with resin, which is beneficial for subsequent processing. Simultaneously, when used as a curing agent for thermosetting resins such as epoxy resins, the presence of numerous benzene and naphthalene ring structures in the polymer molecular chain provides a strong conjugation effect and rigid structure, which can improve the system's heat resistance, optimize dielectric properties, and reduce moisture absorption and coefficient of linear expansion.

[0061] Resin Composition The resin composition of this invention comprises a thermosetting resin and the powdered polycarbodiimide compound. The amount of the powdered polycarbodiimide added is 100%-150%, 150%-200%, or 200%-250% by mass relative to the thermosetting resin.

[0062] Examples of thermosetting resins used in this invention application include epoxy resins, carboxyl resins, amino resins, or hydroxyl resins. From the viewpoints of operability, heat resistance, and ease of acquisition, epoxy resins having two or more epoxy groups per molecule are preferred.

[0063] Epoxy resins are any resins containing two or more epoxy groups in a single molecule, including but not limited to: bisphenol A type epoxy resin (DGEBA), bisphenol F type epoxy resin (DGEBF), bisphenol S type epoxy resin, bisphenol AD ​​type epoxy resin, hydrogenated bisphenol A type epoxy resin, phenolic varnish type epoxy resin, cresol varnish type epoxy resin, trimethylolpropane triglycidyl ether (TMPTGE), pentaerythritol tetraglycidyl ether, etc. (trifunctional or multifunctional glycidyl ether type epoxy resins), 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, etc. (aliphatic glycidyl ether type epoxy resins), phthalic acid diglycidyl ether, adipic acid diglycidyl ether. This includes glycidyl ester epoxy resins, glycidylamine type epoxy resins such as tetraglycidyl diaminodiphenylmethane (TGDDM) and tetraglycidyl-4,4'-diaminodiphenyl ether (TGDDEP), ester-cyclic epoxy resins such as 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate and bis(3,4-epoxycyclohexyl) adipate, halogenated epoxy resins such as tetrabromobisphenol A type epoxy resin and brominated phenolic epoxy resin, phosphorus-containing epoxy resins, silicone-containing epoxy resins, fluorinated epoxy resins, flexible epoxy resins, high-functionality epoxy resins, bio-based epoxy resins such as itaconic acid-based epoxy resins, castor oil-based epoxy resins, and soybean oil-based epoxy resins, and polycyclic aromatic hydrocarbon type epoxy resins such as naphthalene-type epoxy resins. Preferably, these are epoxy resins that are liquid at room temperature or have a low softening point. These resins can be used alone or in combination of two or more types.

[0064] Powdered polycarbodiimide compounds can be used as curing agents for thermosetting resins such as epoxy resins. When using these powdered polycarbodiimide compounds as curing agents for resins such as epoxy resins, on the one hand, the powdered polycarbodiimide compounds can be directly mixed with thermosetting resins without removing the solvent required for dissolution, and can even be mixed under certain heating conditions (below 100°C), optimizing the processing technology; on the other hand, due to the presence of a large number of benzene rings and naphthalene rings, the addition of these powdered polycarbodiimides can also improve the heat resistance of the cured system, reduce the moisture absorption rate of the resin system, optimize dielectric properties, and reduce the coefficient of linear expansion.

[0065] The powdered polycarbodiimide compound improves the heat resistance of epoxy resin. The amount of the powdered polycarbodiimide compound added to the thermosetting resin composition is preferably 0.1-1.5 equivalents, more preferably 0.2-1 equivalents, relative to the epoxy groups in the epoxy resin.

[0066] In order to improve the curing effect of thermosetting resin and powdered polycarbodiimide compound, a certain amount of curing accelerator may be added to the resin composition of this invention.

[0067] There are no special requirements for the curing accelerators mentioned above; common curing accelerators are acceptable, such as imidazole compounds, amine compounds, and organophosphorus compounds. From the perspective of reactivity and accelerating efficiency, imidazole compounds are preferred.

[0068] The imidazole accelerator may be selected from at least one of 2-methylimidazole, 1-dodecyl-2-methyl-3-benzylimidazole chloride, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1,3-dibenzyl-2-methylimidazole chloride, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole trimellitate, 1-benzyl-2-methylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole trimellitate, 1-cyanoethyl-2-undecylimidazole trimellitate, 2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole trimellitate, trimellitate, and 2,4-diamino-6[2'-methylimidazole-(1')]ethyl-S-triazine.

[0069] For the aforementioned curing accelerator, the amount is typically 0.1-3 parts by weight, preferably 0.5-1 parts by weight, relative to 100 parts by weight of the thermosetting resin. The curing accelerator can influence the reaction rate and reaction mechanism between the thermosetting resin and powdered polycarbodiimide, thereby regulating the temperature, time, and properties of the curing process. This accelerates the curing speed of the thermosetting resin, improves the curing effect, and increases the cured strength. In some embodiments, the mass percentage of the curing accelerator in the resin composition can be 0.1%-0.3%, 0.3%-0.5%, 0.5%-0.8%, 0.8%-1.0%, 1.0%-1.2%, 1.2%-1.5%, 0.2%-1.4%, 0.3%-1.3%, 0.4%-1.2%, 0.5%-1.1%, 0.6%-1.0%, 0.7%-0.9%, 0.8%-1.2%, etc.

[0070] For the total amount of the resin composition mentioned above, the combined content of the thermosetting resin, the powdered polycarbodiimide, and the curing accelerator is 90% or more, preferably 95% or more, for example 100%.

[0071] For the above-mentioned resin composition, any kind of additives, such as flame retardants, defoamers, release agents, fillers, etc., can be added without affecting the effect of the present invention.

[0072] The resin composition of the present invention uses powdered polycarbodiimide as a curing agent for thermosetting resins. On the one hand, it increases the high-temperature resistance of the thermosetting resin system, and on the other hand, it reduces the moisture absorption rate of the system, optimizes the dielectric properties, reduces the coefficient of linear expansion, meets the requirements of electronic devices for thermosetting resins, and can be widely used in the field of electronic materials.

[0073] The above description is merely an overview of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the specification. Furthermore, in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, the following specific description is provided through the following embodiments and comparative examples.

[0074] The following examples and comparative examples illustrate the content of this application. It should be noted that the examples and comparative examples described below are exemplary and are only used to explain this application, and should not be construed as limiting the application. Where specific techniques or conditions are not specified in the examples and comparative examples, they shall be performed in accordance with the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0075] The following lists the raw materials used to synthesize powdered polycarbodiimide compounds in the examples and comparative examples below, including details of the compounds.

[0076] The molecular weights of the compounds listed in this specification are theoretical calculations or catalog values.

[0077] [Diisocyanate compounds] NDI: 1,5-Naphthalene diisocyanate; chemical formula C 12 H6N2O2; Molecular weight 210.2; CAS number: 3173-72-6; Pale yellow crystalline flakes; Melting point 130℃, boiling point 244℃, density 1.45 g / cm³ 3 Shanghai McLean Biochemical Technology Co., Ltd.

[0078] MDI: 4,4'-Diphenylmethane diisocyanate; chemical formula C 15 H 10 N₂O₂; Molecular weight 250.25; CAS number: 101-68-8; White solid; Melting point 38℃, boiling point 196℃, density 1.19 g / cm³ 3 Shanghai McLean Biochemical Technology Co., Ltd.

[0079] [Organic compounds, i.e., capping agents] PEA: Phenylethanol; Chemical formula C8H 10O; Molecular weight 122.17; CAS No.: 60-12-8; Colorless liquid; Melting point -27℃, boiling point 219℃, density 1.02g / ml; Shanghai Bid Pharmaceutical Technology Co., Ltd.

[0080] [Carbodiimide polymerization catalyst] 3-Methyl-1-phenyl-2-phosphacyclopentene-1-oxide: Chemical formula C 11 H 13 OP; Molecular weight 192.19; CAS number: 707-61-9; White powder; Melting point 60℃, boiling point 150℃, density 1.11 g / cm³ 3 Shanghai Bid Pharmaceutical Technology Co., Ltd.

[0081] [solvent] DMF: N,N-Dimethylformamide, chemical formula C3H7NO; molecular weight 73.10; CAS number: 68-12-2; colorless transparent liquid; melting point -61℃, boiling point 153℃, density 0.95g / ml; Shanghai Maclean Biochemical Technology Co., Ltd.

[0082] THF: Anhydrous tetrahydrofuran, chemical formula C4H8O; molecular weight 72.11; CAS number: 109-99-9; colorless transparent liquid; melting point -108℃, boiling point 66℃, density 0.89g / ml; Shanghai Maclean Biochemical Technology Co., Ltd.

[0083] Anhydrous ethanol: Chemical formula C2H6O; Molecular weight 46.07; CAS number: 64-17-5; Colorless transparent liquid; Melting point -115℃, boiling point 78.3℃, density 0.789g / ml; Tianjin Fuyu Fine Chemical Co., Ltd.

[0084] In the preparation of powdered polycarbodiimide, analysis and determination were performed using the methods shown below.

[0085] [Infrared Absorption Spectroscopy (IR)] Apparatus used: Fourier transform infrared spectrometer (FT-IR). Instrument model: AlphaSampleCompartmentRT-DLaTGS.

[0086] Differential Scanning Calorimetry (DSC) Instrument used: Differential scanning calorimeter. Instrument model: TA Instruments Q20 Differential Scanning Calorimeter. Measurement temperature range: 25~200℃, heating rate: 5℃ / min.

[0087] Example 1-1 Preparation of powdered polycarbodiimide compound (a) 100 parts by weight of 4,4'-diphenylmethane diisocyanate (MDI), the diisocyanate compound, were first dissolved in 500 parts by weight of DMF (DMF) as the solvent environment. Both were then added to a four-necked flask equipped with a reflux flask and a stirrer. After complete dissolution, 24.4 parts by weight of phenethyl alcohol (an organic compound with a functional group that can react with isocyanate groups), used as a capping agent, and 0.5 parts by weight of 3-methyl-1-phenyl-2-phosphacyclopentene-1-oxide, used as a catalyst for the carbodiimide polymerization reaction, were added. The reaction was carried out at 90°C under nitrogen protection. During the reaction, samples were taken every half hour for infrared absorption spectroscopy, with the observation wavelength ranging from 2260 to 2280 cm⁻¹. -1 The interval between 2120-2140 cm⁻¹ represents the absorption peak of the isocyanate group. -1 The values ​​represent the changes in the absorption peak of the carbodiimide group.

[0088] The wavelength was determined to be 2260-2280 cm⁻¹ using IR spectroscopy. -1 The interval indicates that the absorption peak of the isocyanate group has completely disappeared. The heating reaction is then stopped, and the mixture is cooled to room temperature to obtain a pale yellow, transparent DMF solution containing a polymeric carbodiimide compound.

[0089] The DMF solution containing the polymeric carbodiimide compound was added dropwise to 20 times its mass of anhydrous ethanol to precipitate the compound. The mixture was stirred while adding the ethanol to ensure uniform dispersion, resulting in a dispersion containing polymer particles.

[0090] The resulting turbid liquid containing powdered polycarbodiimide compound was vacuum filtered to obtain powdered polycarbodiimide with a small amount of residual anhydrous ethanol.

[0091] The powdered polycarbodiimide containing a small amount of residual anhydrous ethanol was placed in a vacuum oven at 45°C and dried under vacuum for 24 hours. The final product was a dried powdered polycarbodiimide compound (a). (n=3) Example 2-1 Preparation of powdered polycarbodiimide compound (b) In Example 2-1, except that the diisocyanate compounds in the raw materials were replaced with 4,4'-diphenylmethane diisocyanate (MDI) and 1,5-naphthalene diisocyanate (NDI), and the molar ratio of 4,4'-diphenylmethane diisocyanate to 1,5-naphthalene diisocyanate was 3:1, i.e., 78 parts by mass of 4,4'-diphenylmethane diisocyanate, 22 parts by mass of 1,5-naphthalene diisocyanate, and 25.4 parts by mass of phenylethanol as the end-capping agent, the other conditions were the same as in Example 1-1, and a dry powdered polycarbodiimide compound (b) was finally obtained.

[0092] Example 3-1 Preparation of powdered polymeric carbodiimide compound (c) In Example 3-1, except that the diisocyanate compounds in the raw materials were replaced with 4,4'-diphenylmethane diisocyanate and 1,5-naphthalene diisocyanate, and the molar ratio of 4,4'-diphenylmethane diisocyanate and 1,5-naphthalene diisocyanate was 1:1, that is, 54 parts by mass of 4,4'-diphenylmethane diisocyanate, 46 parts by mass of 1,5-naphthalene diisocyanate, and 26.5 parts by mass of phenylethanol as the end-capping agent were added, the other conditions were the same as in Example 1-1, and a dry powdered polycarbodiimide compound (c) was finally obtained.

[0093] Example 4-1 Preparation of powdered polycarbodiimide compound (d) In Example 4-1, the diisocyanate compounds in the raw materials were replaced with 4,4'-diphenylmethane diisocyanate and 1,5-naphthalene diisocyanate, and the addition ratio of 4,4'-diphenylmethane diisocyanate and 1,5-naphthalene diisocyanate was 1:3, that is, 28 parts by mass of 4,4'-diphenylmethane diisocyanate, 72 parts by mass of 1,5-naphthalene diisocyanate, and 27.7 parts by mass of phenylethanol as the end-capping agent were added. Other conditions were the same as in Example 1-1, and a dry powdered polycarbodiimide compound (d) was finally obtained.

[0094] Example 5-1 Preparation of powdered polycarbodiimide compound (e) In Example 5-1, the diisocyanate compounds in the raw materials were replaced with 100 parts by mass of 1,5-naphthalene diisocyanate and 29 parts by mass of phenylethanol as the end-capping agent. The other conditions were the same as in Example 1-1, and a dry powdered polycarbodiimide compound (e) was finally obtained.

[0095] Comparative Examples 1-2 In Comparative Examples 1-2, 100 parts by weight of 4,4'-diphenylmethane diisocyanate (MDI), 24.4 parts by weight of phenylethanol as the end-capping agent, and 0.5 parts by weight of 3-methyl-1-phenyl-2-phosphacyclopentene-1-oxide as the catalyst were added to a reaction flask without adding a reaction medium or solvent. The reaction was carried out at 90°C for 4 hours under nitrogen protection. However, during the reaction, the reaction system gelled, and the reaction could not proceed.

[0096] Comparative Examples 1-3 Preparation of powdered polycarbodiimide compound (g) In Comparative Examples 1-3, N,N-dimethylformamide (DMF) was replaced with anhydrous tetrahydrofuran (THF). Since the boiling point of anhydrous tetrahydrofuran is 66°C, the reaction temperature of the polymerization reaction was changed to 60°C. Other conditions were the same as in Examples 1-1, and a dry, powdered polycarbodiimide compound (g) was finally obtained.

[0097] Comparative Examples 1-4 Preparation of powdered polycarbodiimide compound (h) In Comparative Examples 1-4, the conditions were the same as in Examples 1-1, except that the vacuum oven temperature was changed from 45°C to 85°C, and a dry, powdered polycarbodiimide compound (h) was finally obtained.

[0098] Comparative Example 2-2 Preparation of powdered polycarbodiimide compound (i) In Comparative Example 2-2, the molar ratio of 4,4'-diphenylmethane diisocyanate and 1,5-naphthalene diisocyanate was changed to 3:1, i.e., 78 parts by mass of 4,4'-diphenylmethane diisocyanate, 22 parts by mass of 1,5-naphthalene diisocyanate, 25.4 parts by mass of phenylethanol (the end-capping agent), and 0.5 parts by mass of 3-methyl-1-phenyl-2-phosphacyclopentene-1-oxide (the catalyst) were added to a reaction flask. No reaction medium or solvent was added, and the reaction was carried out at 90°C under a nitrogen atmosphere. However, during the reaction, the reaction system gelled, and the reaction could not proceed.

[0099] Comparative Examples 2-3 Preparation of powdered polycarbodiimide compound (j) In Comparative Examples 2-3, except that the N,N-dimethylformamide solvent was replaced with anhydrous tetrahydrofuran and the polymerization temperature was replaced with 60°C, the other conditions were the same as in Example 2-1, and a dry powdered polycarbodiimide compound (j) was finally obtained.

[0100] Comparative Examples 2-4 Preparation of powdered polycarbodiimide compound (k) In Comparative Examples 2-4, the conditions were the same as in Example 2-1, except that the vacuum oven temperature was changed from 45°C to 85°C, and a dry, powdered polycarbodiimide compound (k) was finally obtained.

[0101] Comparative Example 3-2 Preparation of powdered polycarbodiimide compound (l) In Comparative Example 3-2, the molar ratio of 4,4'-diphenylmethane diisocyanate and 1,5-naphthalene diisocyanate was changed to 1:1, i.e., 54 parts by mass of 4,4'-diphenylmethane diisocyanate, 46 parts by mass of 1,5-naphthalene diisocyanate, 26.5 parts by mass of phenylethanol (the end-capping agent), and 0.5 parts by mass of 3-methyl-1-phenyl-2-phosphacyclopentene-1-oxide (the catalyst) were added to a reaction flask. No reaction medium or solvent was added, and the reaction was carried out at 90°C under a nitrogen atmosphere. However, during the reaction, the reaction system gelled, and the reaction could not proceed.

[0102] Comparative Example 3-3 Preparation of powdered polycarbodiimide compound (m) In Comparative Example 3-3, except that the N,N-dimethylformamide solvent was replaced with anhydrous tetrahydrofuran and the polymerization temperature was replaced with 60°C, the other conditions were the same as in Example 3-1, and a dry powdered polycarbodiimide compound (m) was finally obtained.

[0103] Comparative Examples 3-4 Powdered polycarbodiimide compound (n) In Comparative Examples 3-4, the conditions were the same as in Example 3-1, except that the capping agent phenylethanol was replaced from 26.5 parts by mass to 13.25 parts by mass, and a dry powdered polycarbodiimide compound (n) was finally obtained.

[0104] Comparative Examples 3-5 Preparation of powdered polycarbodiimide compound (o) In Comparative Examples 3-5, the conditions were the same as in Example 3-1, except that the vacuum oven temperature was changed from 45°C to 85°C, and a dry, powdered polycarbodiimide compound (o) was finally obtained.

[0105] Comparative Example 4-2 Preparation of powdered polycarbodiimide compound (p) In Comparative Example 4-2, the molar ratio of 4,4'-diphenylmethane diisocyanate and 1,5-naphthalene diisocyanate was changed to 1:3, i.e., 28 parts by mass of 4,4'-diphenylmethane diisocyanate, 72 parts by mass of 1,5-naphthalene diisocyanate, 27.7 parts by mass of phenylethanol (the end-capping agent), and 0.5 parts by mass of 3-methyl-1-phenyl-2-phosphacyclopentene-1-oxide (the catalyst) were added to a reaction flask. No reaction medium or solvent was added, and the reaction was carried out at 90°C under nitrogen protection. However, during the reaction, the reaction system gelled, and the reaction could not proceed.

[0106] Comparative Example 4-3 Preparation of powdered polycarbodiimide compound (q) In Comparative Examples 4-3, except that the N,N-dimethylformamide solvent was replaced with anhydrous tetrahydrofuran, the reaction temperature of the polymerization reaction was changed to 60°C, and the other conditions were the same as in Example 4-1, finally yielding a dry powdered polycarbodiimide compound (q).

[0107] Comparative Example 4-4 Powdered polycarbodiimide compound (r) In Comparative Example 4-4, the conditions were the same as in Example 4-1, except that the capping agent phenylethanol was replaced from 27.7 parts by mass to 13.85 parts by mass, and a dry powdered polycarbodiimide compound (r) was finally obtained.

[0108] Comparative Example 4-5 Preparation of powdered polycarbodiimide compound(s) In Comparative Examples 4-5, the conditions were the same as in Example 4-1, except that the vacuum oven temperature was changed from 45°C to 85°C, and a dry, powdered polycarbodiimide compound (s) was finally obtained.

[0109] Comparative Example 5-2 Preparation of powdered polycarbodiimide compound (t) In Comparative Example 5-2, 100 parts by mass of 1,5-naphthalene diisocyanate, 29 parts by mass of phenylethanol (terminant), and 0.5 parts by mass of 3-methyl-1-phenyl-2-phosphacyclopentene-1-oxide (catalyst) were added to a reaction flask without a reaction medium solvent. The reaction was carried out at 135°C under a nitrogen atmosphere. However, during the reaction, the system gelled, and the reaction could not proceed.

[0110] Comparative Example 5-3 Preparation of powdered polycarbodiimide compound (u) In Comparative Examples 5-3, except that the N,N-dimethylformamide solvent was replaced with anhydrous tetrahydrofuran and the polymerization temperature was replaced with 60°C, the other conditions were the same as in Example 5-1, and a dry powdered polycarbodiimide compound (u) was finally obtained.

[0111] Comparative Example 5-4 Powdered polycarbodiimide compound (v) In Comparative Examples 5-4, the conditions were the same as in Example 5-1, except that the capping agent phenylethanol was replaced from 29 parts by mass to 14.5 parts by mass, and a dry powdered polycarbodiimide compound (v) was finally obtained.

[0112] Comparative Example 5-5 Preparation of powdered polycarbodiimide compound (w) In Comparative Example 5-5, the conditions were the same as in Example 5-1, except that the vacuum oven temperature was changed from 45°C to 85°C, and a dry, powdered polycarbodiimide compound (w) was finally obtained.

[0113] [Evaluation Items] (1) Solubility The solubility described in this invention comprises two aspects. One aspect describes the solubility of the polymer in the carbodiimide polymerization reaction. The other aspect describes the solubility of the resulting powdered polycarbodiimide compound in a solvent.

[0114] Solubility in polymerization reactions is judged by whether the reaction becomes turbid, with the evaluation criteria being "clear" and "turbid".

[0115] The solubility of the obtained powdered polycarbodiimide compound was determined by adding 20 parts by mass of the polycarbodiimide compound from the above examples and comparative examples to 100 parts by mass of anhydrous tetrahydrofuran and stirring at room temperature for 10 minutes. Compounds that formed a homogeneous solution were rated as "soluble," while those that did not completely dissolve were rated as "insoluble."

[0116] In addition, the solubility of the polycarbodiimide compound was evaluated by replacing anhydrous tetrahydrofuran with N,N-dimethylformamide, toluene, and dimethyl sulfoxide (DMSO) solvents, following the same procedure. The solubility results are shown in Tables 1 and 2.

[0117] (2) Softening point The obtained powdered polycarbodiimide compound was subjected to temperature scanning tests using a differential scanning calorimeter, with a temperature range of 25-200℃ and a heating rate of 5℃ / min. The peak temperature of the endothermic reaction was determined and used as the softening point.

[0118] (3) Adhesion The obtained powdered polycarbodiimide compound, approximately 2 cm in height, was added to a cubic aluminum container with sides of 3 cm. A load of 1.25 kg was applied to the top. The state of the powder was observed after standing at 40°C for 72 hours. Evaluation criteria: ○ indicates that the powder remained intact; × indicates that it solidified into a plate-like state and did not collapse into powder upon contact.

[0119] (4) Color The resulting powdered polycarbodiimide compound exhibits a color due to the conjugated structure in its molecular chain, generally deepening the yellow hue. Evaluation criteria: The more "+" signs present, the deeper the yellow color.

[0120] In Comparative Examples 1-2, 2-2, 3-2, 4-2, and 5-2, the carbodiimide polymerization reaction gelled during the reaction, making it impossible to proceed with subsequent experimental steps; therefore, they are not listed in the table.

[0121] Table 1 Table 1 shows the experimental results of Examples 1-1 to 5-1. The results show that the powdered polymeric carbodiimide described in this invention has a high softening point and is less prone to sticking during storage. Furthermore, the higher the proportion of NDI, the earlier turbidity appears during the condensation polymerization reaction, due to the solubility of the polymer chains. The powder obtained after the reaction is completed has a darker color, because the conjugation effect between the benzene ring and the naphthalene ring is stronger.

[0122] Table 2 Table 2 shows the test results for the comparative examples. In Comparative Examples 1-3 to 5-3, after replacing the reaction medium with anhydrous THF, the overall reaction temperature decreased and the reaction time increased significantly, which was detrimental to the ease of preparation. Furthermore, the poor solubility of THF in anhydrous THF could negatively impact the uniformity of the carbodiimide polymerization reaction.

[0123] In Comparative Examples 3-4 to 5-4, the average degree of polymerization was increased by halving the mass of phenethyl alcohol, an organic compound with a functional group that can react with isocyanate groups, used as a capping agent in the examples. Example 2-1 was a clear polymerization state, while Comparative Example 2-3 was a suspension. Compared with Examples 3-1 to 5-1, the polymerization reaction time of Comparative Examples 3-3 to 5-3 with suspension was reduced, and polycarbodiimide suspension appeared earlier. At this time, some isocyanate groups had not been completely polymerized, which had a certain impact on the uniformity of the polymerization reaction and prolonged the polymerization reaction time.

[0124] In Comparative Examples 1-5 to 5-5, the temperature of the vacuum oven used to remove residual precipitated solvent was adjusted from 45 degrees Celsius to 85 degrees Celsius. The increase in drying temperature reduced the solubility of the powdered polycarbodiimide compound.

[0125] [Resin composition containing powdered polycarbodiimide compound] The following lists the raw materials used in the resin compositions in the examples and comparative examples below, including details of the compounds.

[0126] [Epoxy Resin] 4032D: 1,6-Dihydroxynaphthalene epoxy resin, Anhui Xinyuan Technology Co., Ltd., product model XY643.

[0127] [Curing agent] Example 1-1: Synthesized powdered polycarbodiimide compound (a) Example 2-1: Synthesized powdered polycarbodiimide compound (b) Example 3-1: Synthesized powdered polycarbodiimide compound (c) Example 4-1: Synthesized powdered polycarbodiimide compound (d) Example 5-1: Synthesized powdered polycarbodiimide compound (e) MHHPA: 4-Methylhexahydrophthalic anhydride; chemical formula C9H 12 O3; Molecular weight 168.19; CAS No.: 19438-60-9; Transparent liquid; Melting point -29℃, boiling point 120℃, density 1.16g / ml; Shanghai Maclean Biochemical Technology Co., Ltd.

[0128] DDM: 4,4'-Diaminodiphenylmethane; Chemical formula C 13 H 14 N2; Molecular weight 198.26; CAS number: 101-77-9; Pale yellow crystalline powder; Melting point 90℃, boiling point 242℃, density 1.15 g / cm³ -3 Shanghai McLean Biochemical Technology Co., Ltd.

[0129] [Curing Accelerator] 1-Methylimidazole: Chemical formula C4H6N2; Molecular weight 82.10; CAS number 616-47-7; Colorless transparent liquid; Melting point -60℃, boiling point 198℃, density 1.03g / ml; Shanghai Maclean Biochemical Technology Co., Ltd.

[0130] Example 6-1 100 parts by weight of 4032D epoxy resin and 268 parts by weight of the powdered polycarbodiimide compound (a) prepared in Example 1-1 were placed in a mortar and ground uniformly at room temperature. The mixture was then cured by hot pressing, and the curing temperature rise stage was determined by DSC testing. A resin composition containing the polycarbodiimide compound was obtained.

[0131] Examples 6-2 to 6-5 Except for replacing the polymeric carbodiimide compound with the composition shown in Table 3, the other conditions were the same as in Example 6-1.

[0132] Comparative Examples 6-6 and 6-7 Except for replacing the curing agent with 4-methylhexahydrophthalic anhydride curing agent and 4,4'-diaminodiphenylmethaneamine curing agent (DDM), the amount added is based on the equimolar reaction of the functional groups, and other conditions are the same as in Example 6-1.

[0133] [Evaluation Items] (1) Glass transition temperature The cured samples obtained from Examples 6-1 to 6-5 and Comparative Examples 6-6 and 6-7 were used to determine the glass transition temperature using a Dynamic Mechanical Analyzer (DMA) with a heating rate of 5°C / min. A higher glass transition temperature indicates better heat resistance and reliability at high temperatures.

[0134] (2) Water absorption rate The cured samples were tested for water absorption under the conditions of the national standard GB / T1034—2008.

[0135] (3) Dielectric properties The dielectric properties of the cured samples were tested under the conditions specified in GB / T40564—2021. The instrument used was an Agilent 4294A (Keysight Technologies). The test results are as follows: Figure 2 As shown.

[0136] (4) Coefficient of linear expansion The obtained cured specimens were tested for their coefficient of linear expansion under the conditions of GB / T1036—2018 using a thermomechanical analyzer TMA / SDTA2+ (Mettler Toledo).

[0137] Experimental data for the examples and comparative examples are listed in Table 3.

[0138] Table 3 As shown in Table 3, the glass transition temperature was significantly increased in the thermosetting resin composition using powdered polymeric carbodiimide compound as the curing agent and imidazole as the curing accelerator. In Examples 6-1 to 6-4, the glass transition temperature increased with increasing naphthyl content. The lower glass transition temperature in Example 6-5 may be due to the increased steric hindrance of the epoxy group reaction during curing when the polymer molecular chain consists entirely of naphthalene rings, preventing the formation of a more complete three-dimensional network structure and thus lowering the glass transition temperature. Simultaneously, the water absorption rate, coefficient of linear expansion, and dielectric properties were also significantly optimized compared to conventional epoxy resin curing agents.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The protection scope of this application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A powdered polycarbodiimide compound, characterized in that, It is represented by the following general formula 1: General Formula 1 In general formula 1, R1 and R3 represent residues of an organic compound having a functional group that can react with an isocyanate group [-NCO] removed, and R1 and R3 may be the same or different; R2 represents a diisocyanate compound having two divalent residues of isocyanate groups removed; X1 and X2 represent groups formed by the reaction of the organic compound with an isocyanate, and X1 and X2 may be the same or different; n represents an integer from 3 to 15.

2. The powdered polycarbodiimide as described in claim 1, characterized in that, R2 represents at least one of chemical formula 1 and chemical formula 2, where chemical formula 1 represents a divalent residue from 1,5-naphthalene diisocyanate with two isocyanate groups removed, and chemical formula 2 represents a divalent residue from 4,4'-diphenylmethane diisocyanate with two isocyanate groups removed. [Chemical Formula 1] [Chemical Formula 2] 。 3. The powdered polycarbodiimide as described in claim 1, characterized in that, The organic compound having a functional group that can react with an isocyanate group includes at least one of monohydric alcohols, monoamines, monocarboxylic acids, acid anhydrides, and monoisocyanates.

4. The method for preparing the powdered polycarbodiimide compound according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Self-precipitation polymerization In the presence of a condensation polymerization catalyst and under heating conditions, a diisocyanate compound and an organic compound having a functional group that can react with an isocyanate group undergo a carbodiimide condensation polymerization reaction in a reaction solvent and form end caps. During the polymerization process, as the degree of polymerization increases, the polycarbodiimide compound precipitates from the solvent, forming fine particles in suspension or sedimentation, resulting in a suspension containing a polycarbodiimide compound as shown in general formula 1. Step 2: Precipitation and drying The suspension obtained in step 1 is added to a poor solvent of polycarbodiimide to precipitate the precipitate, and then filtered and vacuum dried to obtain a powdered polycarbodiimide compound as shown in Formula 1.

5. The preparation method according to claim 4, characterized in that, The molar ratio of the organic compound to the diisocyanate compound is 1:(2-8).

6. The preparation method according to claim 4, characterized in that, The condensation polymerization catalyst is phosphacyclopentene oxide.

7. The preparation method according to claim 4, characterized in that, The reaction solvent includes at least one of alicyclic ethers, aromatic hydrocarbons, and halogenated hydrocarbons.

8. The preparation method according to claim 4, wherein the solvent for the polycarbodiimide includes at least one selected from hexane, cyclohexane, petroleum ether, and anhydrous ethanol; and the vacuum drying temperature is 30-100℃.

9. A resin composition, characterized in that, It includes thermosetting resins and powdered polycarbodiimide compounds as described in any one of claims 1-3 or powdered polycarbodiimide compounds prepared by any one of the preparation methods in claims 4-8.

10. The use of the resin composition as described in claim 9 in electronic devices.

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