Benzooxazine composition and its use

Abstract

The objective of the present invention is to provide a benzoxazine composition the cured product of which has an excellent self-repairing property. The objective is achieved by a benzoxazine composition according to one embodiment of the present invention comprising: a reaction product of a benzoxazine compound and (ii) a compound containing at least two phenolic hydroxyl groups, and / or a mixture of (i) and (ii), and a specific cross-linking agent.

Description

Technical Field

[0001] The present invention relates to a benzoxazine composition and use thereof.

Background Art

[0002] Phenolic resins, epoxy resins and the like are used as raw materials for electronic components, semiconductor sealing materials and the like. In recent years, benzoxazine resins have been used particularly for their excellent heat resistance.

[0003] For example, Patent Document 1 describes a resin composition that contains a phenolic resin and a disulfide compound, and is excellent in metal adhesion and heat resistance of a cured product. It also describes that the phenolic resin may contain a benzoxazine resin.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0005] However, the above-mentioned Patent Document 1 neither discloses nor suggests anything about the self-healing property of the cured product of the resin composition. An object of the present invention is to provide a benzoxazine composition having excellent self-healing properties when formed into a cured product.

Means for Solving the Problems

[0006] As a result of diligent research to solve the aforementioned problems, the present inventors have found that a cured product of a benzoxazine composition comprising (i) a benzoxazine compound and (ii) a compound containing two or more phenolic hydroxyl groups, and / or a mixture of (i) and (ii), as well as a specific crosslinking agent, has excellent self-healing properties, and have completed the present invention.

[0007] That is, one aspect of the present invention is a reaction product of (A) component: (i) a benzoxazine compound and (ii) a compound containing two or more phenolic hydroxyl groups, and / or a mixture of (i) and (ii), (B) A benzoxazine composition comprising a crosslinking agent containing a bond capable of bond exchange reactions and a functional group that reacts with a hydroxyl group.

[0008] Another aspect of the present invention is a reaction product represented by the following formula (1), (A) component: (B) Component: A benzoxazine composition comprising a crosslinking agent represented by the following formula (2).

[0009] [ka] In formula (1), n ​​is an integer, R1 is an aromatic group and / or an aliphatic group, R2 to R5 each independently represent one selected from the group consisting of a halogen atom, an alkyl group, an alkyl halide, a hydroxyl group, a carboxyl group, an amino group, and an alkoxy group, and R6 and R7 each independently represent one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an alkyl halide, a hydroxyl group, a carboxyl group, an amino group, and an alkoxy group.

[0010] [ka] In formula (2), R8 is an aromatic group and / or an aliphatic group and contains a disulfide bond, and X and Y are each independently functional groups that react with a hydroxyl group. [Effects of the Invention]

[0011] According to one aspect of the present invention, a benzoxazine composition having excellent self-healing properties when made into a cured product can be provided. [Brief Description of the Drawings]

[0012] [Figure 1] This is a schematic diagram showing an example of the mechanism by which damage is repaired on the surface of a cured product of the benzoxazine composition according to one embodiment of the present invention. [Figure 2] This is a diagram showing observation images of scratches made on cured products according to examples of the present invention. [Figure 3] This is a diagram showing the results of subjecting the cured products according to the examples of the present invention to hot pressing. [Figure 4] This is a diagram showing the results of dissolving the cured products according to the examples of the present invention in a solvent, as well as the reaction formula when the cured products dissolve. [Modes for Carrying Out the Invention]

[0013] One embodiment of the present invention is described below, but the present invention is not limited thereto. Unless otherwise specified in the present specification, "A to B" representing a numerical range is intended to mean "A or more and B or less".

[0014] [1. Benzoxazine Composition] The benzoxazine composition according to one embodiment of the present invention (hereinafter also referred to as the present benzoxazine composition) comprises component (A): a reaction product of (i) a benzoxazine compound and (ii) a compound containing two or more phenolic hydroxyl groups, and / or a mixture of the aforementioned (i) and the aforementioned (ii), and component (B): a crosslinking agent containing a bond capable of bond exchange reaction and a functional group that reacts with a hydroxyl group.

[0015] As described above, the present inventors have successfully produced a cured product having excellent self-healing properties by curing a benzoxazine composition comprising: (i) a reaction product of a benzoxazine compound and (ii) a compound containing two or more phenolic hydroxyl groups, and / or a mixture of the aforementioned (i) and the aforementioned (ii), as well as a specific crosslinking agent. Such a benzoxazine composition that exhibits excellent self-healing properties even when formed into a cured product has not existed conventionally, which is surprising.

[0016] In the present specification, the "reaction product of (i) and (ii)" means a state where (i) and (ii) have already reacted before the composition is cured. On the other hand, the "mixture of (i) and (ii)" means a state where (i) and (ii) are unreacted before the composition is cured. The mixture can generate the above reaction product upon heating for curing. Accordingly, the same effect can be obtained whether the above reaction product is used or the above mixture is used. Details will be described later.

[0017] In the present specification, "having self-healing properties" means that when a scratched cured product is heated, the width and / or length of the scratch becomes smaller than that before heating.

[0018] Further, in the present specification, "having excellent self-healing properties" means that when a cured product having scratches with a width of 10 μm or less is heated at 200°C for 1 hour, the healing rate represented by the following formula is 40% or more. Healing rate (%) = (Area of scratch before heating - Area of scratch after heating) / (Area of scratch before heating) × 100 The mechanism of self-healing properties in the cured product of the present benzoxazine composition may be, for example, as shown in Figure 1. The schematic diagram shown in Figure 1 is merely an example of the reaction when the present benzoxazine composition contains the compounds shown in the Examples as component (A) and component (B), and does not limit the reaction mechanism of the present invention. Further, although a disulfide bond is exemplified as a bond capable of bond exchange reaction, this is merely an example and does not limit the bond that the crosslinking agent has.

[0019] The repair mechanism of the cured product will be explained in detail below using Figure 1. First, when the benzoxazine composition is cured by heating, the phenolic hydroxyl groups contained in the reaction product of the benzoxazine compound (component A) and a compound having two or more phenolic hydroxyl groups react with the epoxy groups contained in the crosslinking agent (component B). As a result, the reaction product 1 of component (A) shown in step 11 is crosslinked by the crosslinking agent 2. If damage occurs to the cured product in which the reaction products of component (A) are crosslinked by the crosslinking agent 2, the cured product is heated further. As a result, the disulfide bond 3 contained in the crosslinking agent 2 dissociates and recombines, creating the disulfide bond 4 shown in step 12. Further heating of the cured product causes movement of the reaction product 1 (main chain) portion, and the disulfide bond 4 dissociates. Subsequently, recombination occurs, creating the disulfide bond 5. The crosslinking agents 2 enclosed by the dashed lines recombine via disulfide bonds 5, resulting in the crosslinked structure shown in step 13. Similarly, when a mixture of a benzoxazine compound and a compound having two or more phenolic hydroxyl groups is used as component (A), a change in the crosslinked structure occurs as a reaction product when the benzoxazine composition is cured by heating. Therefore, by combining components (A) and (B), the cured product can be made to have excellent self-healing properties.

[0020] Thus, with this benzoxazine composition, a self-healing cured product can be obtained through the simple operation of heating. Therefore, the cured product of this benzoxazine composition can be used for a long period of time.

[0021] Furthermore, with the configuration described above, even if the hardened material is damaged, it can be repaired by heating and reused, thus contributing to the achievement and realization of Sustainable Development Goal (SDG) 12, "Ensure sustainable consumption and production patterns."

[0022] A benzoxazine composition according to another embodiment of the present invention comprises (A) a reaction product represented by the following formula (1) and (B) a crosslinking agent represented by the following formula (2).

[0023] [ka] In formula (1), n ​​is an integer, R1 is an aromatic group and / or an aliphatic group, R2 to R5 are each independently selected from the group consisting of halogen atoms, alkyl groups, alkyl halides, hydroxyl groups, carboxyl groups, amino groups, and alkoxy groups, and R6 and R7 are each independently selected from the group consisting of hydrogen atoms, halogen atoms, alkyl groups, alkyl halides, hydroxyl groups, carboxyl groups, amino groups, and alkoxy groups.

[0024] [ka] In formula (2), R8 is an aromatic group and / or an aliphatic group and contains a disulfide bond, and X and Y are each independently functional groups that react with a hydroxyl group.

[0025] <1-1. (A) Component> Component (A) contained in this benzoxazine composition is a reaction product of (i) a benzoxazine compound and (ii) a compound containing two or more phenolic hydroxyl groups, and / or a mixture of (i) and (ii). In other words, component (A) may contain the reaction product of (i) and (ii), a mixture of (i) and (ii), or both the reaction product and the mixture.

[0026] If component (A) is the reaction product of (i) and (ii), then (i) and (ii) may be reacted by heating and stirring, and then mixed with component (B), which will be described later. Alternatively, if component (A) is a mixture of (i) and (ii), then components (i), (ii), and (B) may be mixed simultaneously. If the benzoxazine composition contains the reaction product and unreacted (i) and / or (ii), then component (A) can be said to contain the reaction product and mixture of (i) and (ii).

[0027] The (i) benzoxazine compound is not particularly limited as long as it is a compound containing a benzoxazine ring. Examples of the (i) benzoxazine compound include the compound represented by the following formula (3). [ka] In formula (3), R1 is an aromatic group and / or an aliphatic group. R1 may also be an aliphatic group, or it may be a plurality of aliphatic groups linked via ether bonds.

[0028] Examples of the aforementioned aromatic groups include phenylene group, biphenylene group, naphthylene group, anthranylene group, phenanthylene group, pyrenylene group, colonylene group, terphenylene group, furanylene group, thienylene group, or fluorenylene group.

[0029] In this specification, aromatic groups also include structures in which the phenylene group, biphenylene group, naphthylene group, anthranylene group, phenanthylene group, pyrenylene group, colonylene group, terphenylene group, furanylene group, thienylene group, or fluorenylene group are linked by one or more divalent linking groups, either between two or more identical groups or two or more different groups. Furthermore, the aromatic groups also include non-benzene aromatic groups and heteroaromatic groups.

[0030] Examples of the aforementioned divalent linking groups include alkylene groups, ether groups, carbonyl groups, amide groups, imino groups, azo groups, sulfide groups, sulfonyl groups, sulfide groups, isopropylidene groups, hexafluorinated isopropylidene groups, and the like. Examples of the aforementioned nonbenzene-based aromatic groups include annulene, azulene, tropone, metallocene, and other aromatic compounds having three-membered ring structures, five-membered ring structures, or seven-membered ring structures.

[0031] If the aromatic group has substituents, examples of substituents include halogen atoms, alkyl groups, cycloalkyl groups, alkyl halides, hydroxyl groups, carboxyl groups, amino groups, alkoxy groups, cyano groups, aryloxy groups, aralkyloxy groups, and the like.

[0032] The aromatic group preferably has 6 to 200 carbon atoms, and more preferably 6 to 50 carbon atoms.

[0033] The aliphatic group may be linear or cyclic, and may be saturated or unsaturated. Furthermore, if the aliphatic group is linear, it may be linear or branched. Examples of linear aliphatic groups include alkylene groups, alkenylene groups, and alkynylene groups. An example of a cyclic aliphatic group is a cycloalkylene group.

[0034] Examples of alkylene groups include methylene, ethylene, propylene, butylene, pentylene, and hexylene groups. Examples of alkenylene groups include vinylene, 1-methylvinylene, propenylene, butenylene, and pentenylene groups. Examples of alkylylene groups include ethynylene, propynylene, butynylene, pentynylene, and hexynylene groups. Examples of cycloalkylene groups include cyclopropylene, cyclobutylene, cyclopentylene, and cyclohexylene groups.

[0035] Furthermore, one or more hydrogen atoms contained in the aliphatic group may be substituted with a halogen atom, a hydroxyl group, or an alkoxy group.

[0036] The number of carbon atoms in the aliphatic group is preferably 1 to 100, more preferably 1 to 60, and even more preferably 1 to 50. When the number of carbon atoms is within the above range, the cured product exhibits excellent self-healing properties.

[0037] In formula (3) above, R2 to R5 each independently represent one selected from the group consisting of a halogen atom, an alkyl group, an alkyl halide, a hydroxyl group, a carboxyl group, an amino group, and an alkoxy group.

[0038] The compound (ii) containing two or more phenolic hydroxyl groups is not particularly limited as long as it has two or more phenolic hydroxyl groups. That is, it may be a diphenol, a triphenol, or a tetraphenol.

[0039] Examples of compounds containing two or more phenolic hydroxyl groups include the compound represented by the following formula (4).

[0040] [ka] In formula (4), R6 and R7 each independently represent one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an alkyl halide, a hydroxyl group, a carboxyl group, an amino group, and an alkoxy group. Both R6 and R7 may be hydrogen atoms.

[0041] Examples of compounds represented by formula (4) include resorcinol, alkyl resorcinol (2-methylresorcinol, 5-methylresorcinol, 2,5-dimethylresorcinol, 2-ethylresorcinol, 2-propylresorcinol, 2-n-butylresorcinol, 2-tert-butylresorcinol, 5-n-pentylresorcinol, 5-n-heptylresorcinol, etc.), alkoxyresorcinol (2-methoxyresorcinol, 5-methoxyresorcinol, etc.), 2-aminoresorcinol, pyrogallol, and 5-methylpyrogallol.

[0042] If component (A) is a reaction product of (i) and (ii) above, it can be represented by the following formula (1).

[0043] [ka] In formula (1), R1 to R7 are as described above. Furthermore, in formula (1), the hydroxyl group located in the ortho position relative to R2 or R4 is a hydroxyl group derived from a benzoxazine compound, and the hydroxyl group located in the ortho position relative to R7 is a hydroxyl group derived from a compound containing two or more phenolic hydroxyl groups.

[0044] In formula (1) above, the weight-average molecular weight of component (A) is preferably 3,000 to 20,000, more preferably 4,000 to 20,000, and even more preferably 5,000 to 20,000, from the viewpoint of self-healing properties. Note that since n in formula (1) above, which is determined by GPC measurement, is calculated as an average value, it is difficult to accurately specify the range of n.

[0045] For example, as component (A), a compound represented by the following formula (5) can be used.

[0046] [ka] If component (A) is a reaction product of (i) and (ii) described above, the content of component (A) in this benzoxazine composition is preferably 30 to 99% by weight, more preferably 35 to 90% by weight, and even more preferably 40 to 80% by weight. If the content of component (A) is within the above range, the self-healing properties are excellent.

[0047] If component (A) is a mixture of (i) and (ii) described above, the content of (i) in component (A) is preferably 30 to 99% by weight, more preferably 50 to 95% by weight, and even more preferably 80 to 95% by weight. Also, the content of (ii) in component (A) is preferably 1 to 70% by weight, more preferably 5 to 50% by weight, and even more preferably 5 to 20% by weight.

[0048] (A) Component may be chemically synthesized or a commercially available product may be used. When chemically synthesizing component (A), it can be synthesized, for example, by the methods described in Production Example 1 and Production Example 2 below. An example of a method for synthesizing component (A) is described below.

[0049] For example, the (i) benzoxazine compound in component (A) is obtained by mixing and heating a diphenol component, a diamine component, and a component such as formaldehyde or paraformaldehyde that produces formaldehyde. For example, first, a diamine component and a component such as formaldehyde or paraformaldehyde that produces formaldehyde are heated and mixed, then twice the molar amount of the diphenol component as the diamine component is added, and the mixture is reacted at a temperature of 150°C or lower, particularly 100°C or lower, to obtain the (i) benzoxazine compound.

[0050] Furthermore, for example, by mixing an equimolar amount of the (i) benzoxazine compound and a compound containing two or more phenolic hydroxyl groups and reacting them at a temperature of 150°C or lower, particularly 100°C or lower, the reaction product of (i) and (ii) can be obtained.

[0051] <1-2.(B) Component> Component (B) is a crosslinking agent containing bonds capable of bond exchange reactions and functional groups that react with hydroxyl groups.

[0052] Examples of the interchangeable bonds or structures include disulfide bonds, ester bonds, imine bonds, carbonate bonds, urethane bonds, urea bonds, boroxine structures, dioxaborolane structures, vinylogue urethane structures, silyl ether structures, and olefin structures. Among these, from an overall viewpoint of ease of synthesis, bond stability, cost, and ease of bond exchange (whether dissociation and recombination are easy by heating, etc.), the interchangeable bond is preferably a disulfide bond.

[0053] If component (B) contains a disulfide bond, component (B) may be a compound represented by the following formula (2).

[0054] [ka] In formula (2), R8 is an aromatic group and / or an aliphatic group and contains a disulfide bond. R8 may be, for example, an aromatic group linked via a disulfide bond.

[0055] Examples of the aromatic group include phenylene groups, benzyene groups, naphthylene groups, and torylene groups. If the aromatic group has substituents, examples of substituents include halogen atoms, alkyl groups, alkyl halides, alkoxy groups, cyano groups, and aryloxy groups. The aromatic group also includes non-benzene aromatic groups and heteroaromatic groups.

[0056] In formula (2) above, X and Y are each a functional group that reacts independently with a hydroxyl group. X and Y may be the same functional group or different functional groups. Examples of functional groups that react with a hydroxyl group include epoxy groups, carboxyl groups, acid anhydride groups, isocyanate groups, oxazoline groups, etc. From the viewpoint of high reactivity of component (A) with phenolic hydroxyl groups and low generation of by-products, the functional group that reacts with the hydroxyl group is preferably an epoxy group.

[0057] Component (B) may be, for example, a compound represented by the following formula (6).

[0058] [ka] (B) Component may be chemically synthesized or a commercially available product may be used. If chemically synthesized, it can be synthesized, for example, by the method described in Production Example 3 below.

[0059] The ratio (X) / (Y) of the equivalent amount (X) of phenolic hydroxyl groups contained in component (A) to the equivalent amount (Y) of functional groups that react with the hydroxyl groups in component (B) is preferably 0.25 or more, more preferably 0.4 or more, and even more preferably 0.5 or more. The upper limit of the ratio (X) / (Y) is not particularly limited, but may be, for example, 5 or less. The ratio (X) / (Y) can be appropriately adjusted by the weight ratio of component (A) and component (B). If the ratio (X) / (Y) is within the above range, the self-healing properties of the resulting cured product will be improved.

[0060] (others) This benzoxazine composition may optionally contain fillers, release agents, flame retardants, colorants, coupling agents, etc. These may be mixed during the manufacturing of the benzoxazine composition or during the curing process.

[0061] [2. Cured product] A cured product can be obtained by curing this benzoxazine composition. The curing method for the cured product is not particularly limited, but since this benzoxazine composition is thermosetting, it may be cured by heating.

[0062] The heating temperature used to cure this benzoxazine composition is not particularly limited as long as the composition can be sufficiently cured, but may be, for example, 120 to 240°C. Similarly, the heating time is not particularly limited, but may be, for example, 5 minutes to 24 hours. The heating temperature may be constant throughout the heating process, or it may be changed as needed. Heating may be performed in one go, or in multiple stages. Even when heating is performed multiple times, the heating temperature and time do not need to be constant.

[0063] When this benzoxazine composition is used to make a cured product, it may be heated under pressure. The pressure applied to the benzoxazine composition is not particularly limited, but may be, for example, 0.1 to 2.0 MPa. Pressurization may be performed simultaneously with heating or after heating.

[0064] The cured product preferably contains reinforcing fibers from the viewpoint of improving the mechanical strength of the cured product. Examples of reinforcing fibers include inorganic fibers, organic fibers, metal fibers, or reinforcing fibers with a hybrid configuration combining these. The reinforcing fibers may be of one type or two or more types.

[0065] Examples of inorganic fibers include carbon fibers, graphite fibers, silicon carbide fibers, alumina fibers, tungsten carbide fibers, boron fibers, and glass fibers. Examples of organic fibers include aramid fibers, high-density polyethylene fibers, and other general nylon fibers and polyester fibers. Examples of metallic fibers include stainless steel and iron fibers. In addition, carbon-coated metallic fibers, which are metallic fibers coated with carbon, are also included. Among these, carbon fibers are preferable as reinforcing fibers from the viewpoint of increasing the strength of the hardened product.

[0066] Generally, the carbon fibers are sizing-treated, but they can be used as is, or, if necessary, fibers with less sizing agent may be used, or the sizing agent can be removed by existing methods such as organic solvent treatment or heat treatment. In addition, the fiber bundles of carbon fibers may be opened in advance using air or rollers, and treated to facilitate resin impregnation between the individual carbon fibers.

[0067] The glass transition temperature (Tg) of the cured product is preferably -20°C or higher, and more preferably -15°C or higher. There is no particular upper limit to Tg, but in practice it may be 200°C or lower. If Tg is within the above range, a suitable balance can be maintained between the self-healing properties and other physical properties (e.g., mechanical properties) of the cured product.

[0068] The 5% weight loss temperature (Td5) of the cured product is preferably 220°C or higher, more preferably 230°C or higher, and even more preferably 240°C or higher. If the Td5 of the cured product is 220°C or higher, the cured product has excellent heat resistance and is less likely to deteriorate when repaired by the method described later. In this specification, "5% weight loss temperature (Td5)" means the temperature at which the cured product undergoes thermal decomposition and its weight decreases by 5%.

[0069] The average repair rate of the cured product is preferably 40% or more, more preferably 50% or more, even more preferably 60% or more, and even more preferably 65% ​​or more. If the average repair rate of the cured product is 40% or more, it can be said that the cured product has excellent self-healing properties. The higher the average repair rate of the cured product, the better, but it may be, for example, 100% or less, or 90% or less. In this specification, "excellent self-healing properties" and "average repair rate" are as described above in [1. Benzoxazine Composition].

[0070] The cured product can be suitably used in electronic materials such as electronic components, laminates for printed circuit boards and printed circuit boards, semiconductor encapsulation materials, and semiconductor mounting modules, as well as in automobiles or vehicles, aircraft parts, building materials, machine tools, and the like. In particular, it can be used in parts that require heat resistance.

[0071] [3. Methods for repairing hardened materials] A method for repairing a cured product according to one embodiment of the present invention includes the step of heating the cured product of the benzoxazine composition. Therefore, with the benzoxazine composition, the cured product can be repaired simply by heating.

[0072] The heating temperature and heating time when repairing the hardened material can be appropriately set depending on the composition, etc. The heating temperature may be, for example, 50 to 300°C, 100 to 250°C, or 200 to 250°C. The heating time may be, for example, 5 minutes to 5 hours, or 30 minutes to 2 hours.

[0073] [4. Method for reshaping the cured product] A method for reshaping a cured product according to one embodiment of the present invention includes the steps of heating and pressurizing the cured product of the benzoxazine composition. Since the cured product of the benzoxazine composition preferably has excellent reshaping properties, it can be reshaped into a desired shape by heating and pressurizing.

[0074] In this specification, "having remoldability" means that a cured product, once hardened, can be reshaped into a desired shape. In this specification, "having excellent remoldability" means that when the cured product is heated to 180°C or higher and pressurized to 1 MPa or higher (gauge pressure of a press machine), the deformation rate of the cured product by heating and pressing, as expressed by the following formula, is 35 or higher.

[0075] Deformation rate of a hardened product due to hot pressing = (Projection area of ​​the hardened product when viewed from directly above after heating and pressing (mm²) 2 ))÷(Projection area (mm²) of the hardened material (sphere) before heating and pressurizing, viewed from directly above 2 )) However, if the spherical hardened material does not spread uniformly and there are holes in the hardened material after heating and pressurizing, those holes shall not be included in the area of ​​the hardened material calculated using the above formula.

[0076] The heating temperature and pressure used when reshaping the cured product can be appropriately set depending on the composition, etc. The heating temperature may be, for example, 50 to 250°C or 100 to 200°C. The pressure may be 0.01 to 10 MPa or 0.1 to 1 MPa.

[0077] [5. Methods for decomposing and reusing hardened materials] A method for decomposing a cured product according to one embodiment of the present invention comprises the step of heating the cured product of the benzoxazine composition in a solvent containing a reducing agent. Since the cured product of the benzoxazine composition preferably has excellent decomposability, it can be reused after being decomposed by heating in a solvent containing a reducing agent and then recovered.

[0078] In this specification, "degradable" means that when the cured material is heated in a solvent containing a reducing agent, the cured material completely dissolves. Furthermore, if the weight of the remaining cured material is 0.1% or less of the weight of the material before heating when heated at 90°C for 1 hour in a solvent containing a reducing agent, it can be said that the material has excellent degradability.

[0079] If the cured product contains reinforcing fibers, the decomposition method of the cured product includes a step of heating the cured product of the benzoxazine composition in a solvent containing the reducing agent to decompose the parts other than the reinforcing fibers. In other words, if the cured product contains reinforcing fibers, it is sufficient that at least the parts other than the reinforcing fibers are decomposed in the decomposition step.

[0080] Examples of the aforementioned solvents include N,N-dimethylformamide (DMF), N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N,N-diethylacetamide, N-methylcaprolactam, γ-butyrolactone, cyclohexanone, dimethyl sulfoxide, cyclopentanone, and 1,4-dioxane.

[0081] Examples of reducing agents included in the solvent include (±)-dithiothreitol, 2-mercaptoethanol, 2-mercaptoethylamine hydrochloride, cysteine ​​hydrochloride, and tris(2-carboxyethyl)phosphine hydrochloride. The concentration of the reducing agent in the solvent may be, for example, 0.1 to 10 mg / mL.

[0082] The heating temperature for decomposing the hardened material may be, for example, 70 to 120°C. The decomposition time may be 5 minutes to 5 hours, and stirring may be performed as appropriate during the decomposition process.

[0083] The decomposition products of the cured product obtained by the above decomposition method can be recovered and reused. Specifically, the decomposition products of the cured product can be recovered from the solvent by drying the decomposition solution or by mixing the decomposition solution with a poor solvent to precipitate and obtain the solid components (decomposition products of the cured product), and the recovered decomposition products of the cured product can be reacted in the presence of an oxidizing agent to produce a new cured product.

[0084] If the cured product subjected to the above decomposition method contains reinforcing fibers, both the decomposition products of the cured product and the reinforcing fibers can be recovered and reused. Specifically, first, the decomposition products of the cured product and the reinforcing fibers are separated and recovered by filtration or centrifugation. Then, the decomposition liquid containing the decomposition products of the cured product is dried, or the decomposition liquid is mixed with a poor solvent to precipitate and obtain the solid components (the decomposition products of the cured product), thereby recovering the decomposition products of the cured product from the solvent. The recovered decomposition products of the cured product can then be reacted in the presence of an oxidizing agent to produce a cured product containing reinforcing fibers again.

[0085] [6. Prepreg or semipreg] A prepreg or semipreg according to one embodiment of the present invention is obtained by impregnating reinforcing fibers with the benzoxazine composition. In this specification, semipreg means a composite formed by partially impregnating (semi-impregnated) reinforcing fibers with the benzoxazine composition.

[0086] Furthermore, a prepreg can be obtained from the semipreg. For example, a prepreg can be obtained by further heating and melting the semipreg to impregnate the reinforcing fibers with resin.

[0087] As reinforcing fibers used in prepregs or semipregs, those described in [2. Cured Products] above may be used as appropriate.

[0088] The resin content impregnating the reinforcing fibers is preferably 10 to 60% by weight, and more preferably 20 to 50% by weight. The resin content refers to the weight ratio of the resin to the combined weight of the resin and the reinforcing fibers.

[0089] The aforementioned prepreg or semipreg can be used, for example, to create a laminate for printed circuit boards by heating and pressurizing it together with metal foil, and then forming circuits on the laminate to produce a printed circuit board. The printed circuit board thus produced has excellent heat resistance and mechanical properties, and is therefore suitable for use as a semiconductor mounting substrate and the like.

[0090] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0091] One embodiment of the present invention may include the following configuration. <1> (A) Components: (i) a benzoxazine compound and (ii) a compound containing two or more phenolic hydroxyl groups, and / or a mixture of (i) and (ii), (B) A benzooxazine composition comprising a crosslinking agent containing a bond capable of bond exchange and a functional group that reacts with a hydroxyl group. <2> The bond capable of the aforementioned bond exchange reaction is a disulfide bond. <1> The benzoxazine composition described above. <3> (A) Component: Reaction product represented by the following formula (1), (B) A benzoxazine composition comprising a crosslinking agent represented by the following formula (2).

[0092] [ka] In formula (1), n ​​is an integer, R1 is an aromatic group and / or an aliphatic group, R2 to R5 each independently represent one selected from the group consisting of a halogen atom, an alkyl group, an alkyl halide, a hydroxyl group, a carboxyl group, an amino group, and an alkoxy group, and R6 and R7 each independently represent one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an alkyl halide, a hydroxyl group, a carboxyl group, an amino group, and an alkoxy group.

[0093] [ka] In formula (2), R8 is an aromatic group and / or an aliphatic group and contains a disulfide bond, and X and Y are each independently functional groups that react with a hydroxyl group. <4> The functional group that reacts with the hydroxyl group is an epoxy group. <1> ~ <3> A benzoxazine composition as described in any one of the following. <5> The ratio (X) / (Y) of the equivalent amount (X) of phenolic hydroxyl groups contained in component (A) to the equivalent amount (Y) of functional groups that react with the hydroxyl groups in component (B) is 0.25 or greater. <1> ~ <4> A benzoxazine composition as described in any one of the following. <6> <1> ~ <5> A cured product obtained by curing any one of the benzoxazine compositions described in the following. <7> Furthermore, it contains reinforcing fibers, <6> The cured product described above. <8> <6> or <7> A method for repairing a hardened material, comprising the step of heating the hardened material described above. <9> <6> or <7> A method for reshaping a cured product, comprising the steps of heating and pressurizing the cured product described above. <10> <6> or <7> A method for decomposing a cured product, comprising the step of heating the cured product described above in a solvent containing a reducing agent. <11> <7> A method for decomposing a cured product, comprising the step of heating the cured product described above in a solvent containing a reducing agent to decompose the parts other than the reinforcing fibers. <12> <10> A method for reusing hardened material, comprising the step of recovering and reusing the decomposed products of the hardened material obtained by the decomposition method described above. <13> <11> A method for reusing hardened material, comprising the step of recovering and reusing the decomposed material and reinforcing fibers obtained by the decomposition method described above. <14> <1> ~ <5> A prepreg or semipreg obtained by impregnating reinforcing fibers with any one of the benzoxazine compositions described in any one of the above. [Examples]

[0094] One embodiment of the present invention will be described in more detail below with reference to examples and comparative examples. The present invention is not limited to the following examples.

[0095] [Test Method] (Structural analysis of benzoxazine compounds and crosslinking agents) The molecular structure of benzoxazine compounds and crosslinking agents was analyzed using a nuclear magnetic resonance spectrometer (NMR, Bruker AVANCEIII 400MHz) with 16 integration cycles under room temperature conditions. 1 This was performed by 1H-NMR measurement.

[0096] (Molecular weight measurement of benzoxazine compounds and reaction products of benzoxazine compounds and 2-methylresorcinol) The molecular weights of benzoxazine compounds and the reaction products of benzoxazine compounds and 2-methylresorcinol were evaluated using a gel permeation chromatography (GPC) system (Prominence UFLC, Shimadzu Corporation) under the following conditions: eluent was 0.01 mol / L lithium chloride-containing DMF, three TSKgel GMHHR-M columns connected in series, flow rate 1 mL / min, injection volume 20 μL, column temperature 40°C, UV detector, and polystyrene sample for the calibration curve.

[0097] (Glass transition temperature (Tg) of the cured product) For the cured product, the DSC curve was measured using a differential scanning calorimetry system (DSC, Hitachi High-Tech Science Corporation, DSC7000X) under conditions of 10°C / min and a nitrogen flow rate of 40 mL / min. The extrapolated glass transition onset temperature (the intersection of a straight line obtained by extrapolating the baseline before the inflection point to the higher temperature side and the tangent line at the inflection point) obtained from the obtained DSC curve was defined as the glass transition temperature in this specification.

[0098] (Thermal stability of cured products) For the cured material, the 5% weight loss temperature (Td5) was evaluated using a thermogravimetric analyzer (STA7200, Hitachi High-Tech Science Corporation) at a heating rate of 5°C / min under a nitrogen flow of 200 mL / min.

[0099] (Evaluation of the restorative properties of hardened materials) For the cured material, cuts less than 10 μm wide were made on the surface of the cured material with a cutter, and then the cured material was heated in air at 200°C for 1 hour. The cuts before and after heating were observed with a digital microscope (Keyence Corporation, VHX-200), and the repair rate was calculated from the changes in the cuts using the following formula to evaluate the repairability.

[0100] Repair rate (%) = (Area of ​​damage before heating - Area of ​​damage after heating) / (Area of ​​damage before heating) × 100 (Evaluation of the reshapeability of the cured product) Spherical hardened materials (weighing approximately 10 mg) with a diameter of 3-4 mm were manufactured and heated and pressed using a hot press machine (Mini Test Press 10, manufactured by Toyo Seiki Seisakusho Co., Ltd.) at 180°C for 15 minutes at 1 MPa (gauge pressure). The degree of expansion of the hardened material was calculated as the deformation rate using the following formula, and its remolding properties were evaluated.

[0101] Deformation rate of a hardened product due to hot pressing = (Projection area of ​​the hardened product when viewed from directly above after heating and pressing (mm²) 2 ))÷(Projection area (mm²) of the hardened material (sphere) before heating and pressurizing, viewed from directly above 2 )) However, if the spherical hardened material does not spread uniformly and there are holes in the hardened material after heating and pressurizing, those holes shall not be included in the area of ​​the hardened material calculated using the above formula.

[0102] (Evaluation of the decomposition properties of the hardened material) 10 mg of the cured material was immersed in either 5 mL of DMF or 5 mL of DMF containing 2 mg of (±)-dithiothreitol, and heated and stirred at 90°C for 1 hour. The degree of dissolution of the cured material was visually determined to evaluate its degradability.

[0103] [Manufacturing Example 1] Jeffamine ED-900 (10.0357 g, 0.0112 mol) and paraformaldehyde (1.5644 g, 0.0489 mol) were added to a reaction vessel equipped with a stirring bar, and the mixture was stirred at 100°C for 30 minutes. Subsequently, 2,4-dimethylphenol (2.7191 g, 0.0225 mol) was added to the reaction mixture, and the mixture was stirred at 100°C for 14 hours. After the reaction mixture was cooled to room temperature, 60 mL of chloroform was added to the reaction mixture, and liquid-liquid extraction was carried out three times with 100 mL of 0.1 mol / L sodium hydroxide aqueous solution and three times with 100 mL of pure water. The organic layer solution was mixed with 100 mL of hexane, and the supernatant was collected. The solvent was removed using an evaporator at 30°C under reduced pressure to obtain the target benzoxazine compound. GPC measurement revealed that the weight-average molecular weight (Mw) of the obtained target compound was 4600. 1 By measuring with 1H-NMR (using DMSO-d6 as the deuterated solvent), we observed the disappearance of the 6.8 ppm peak for 2,4-dimethylphenol (starting material) and the emergence of peaks for 3.9 ppm and 4.9 ppm benzoxazine compounds (products), confirming that the target product had been synthesized.

[0104] [Manufacturing Example 2] The benzoxazine compound (5.0027 g, 0.0042 mol) and 2-methylresorcinol (0.5207 g, 0.0042 mol) obtained in Preparation Example 1 were added to a reaction vessel and stirred at 100°C for 3 hours to obtain the reaction products of the benzoxazine compound and 2-methylresorcinol. GPC measurement confirmed that the weight-average molecular weight (Mw) of the obtained target product was 6900, thus confirming that the compound of formula (5) was obtained.

[0105] [Manufacturing Example 3] In a 100 mL round-necked flask equipped with a stirring bar, bis(4-hydroxyphenyl) disulfide (2.0000 g, 0.0080 mol), potassium carbonate (11.0438 g, 0.0799 mol), and N,N-dimethylformamide (37.77 g) were added. Subsequently, under a nitrogen stream, the mixture was heated to 60°C while stirring, and epibromohydrin (10.9000 g, 0.0796 mol) was gradually added dropwise using a dropping funnel. After that, the remaining epibromohydrin in the dropping funnel was washed with N,N-dimethylformamide (5.0000 g) and added to the reaction mixture. After reacting at 60°C for 4.5 hours, the mixture was cooled to room temperature, and potassium carbonate was recovered by suction filtration and washed with N,N-dimethylformamide (48.00 g). Next, 50.00 g of pure water was added to the filtrate, and extraction was performed three times with a mixed solvent of chloroform and hexane (the volume ratio of chloroform to hexane was 4:6) to extract the target product into the organic layer. The organic layer was washed three times with pure water and once with saturated brine, then dehydrated with sodium sulfate, and the solvent was removed under reduced pressure using an evaporator. Subsequently, recrystallization from methanol was performed, and the solid obtained by recrystallization was recovered by filtration and vacuum-dried at 60°C to obtain the target product, bis(4-glycidyloxyphenyl) disulfide (a crosslinking agent containing a disulfide bond). 1 ¹H-NMR measurements (using deuterated chloroform as the deuterated solvent) revealed peaks of benzene ring protons derived from the starting material bis(4-hydroxyphenyl) disulfide at 7.39 ppm and 6.85 ppm, peaks of methylene group protons adjacent to the ether bond at 4.23 ppm and 3.93 ppm, a proton peak of the tertiary carbon of the epoxy group at 3.37-3.34 ppm, and proton peaks of the secondary carbon of the epoxy group at 2.92 ppm and 2.76 ppm, confirming that the target compound of formula (6) had been synthesized.

[0106] [Raw material compound] The raw materials used in the following examples and comparative examples are as follows.

[0107] <(A) Component: Reaction product or mixture of a benzoxazine compound and a compound containing two or more phenolic hydroxyl groups> A mixture of the compound of formula (5) synthesized in Production Example 2, or the benzooxidine compound synthesized in Production Example 1, and 2-methylresorcinol. <(B) Component: A crosslinking agent containing a bond capable of bond exchange reactions and a functional group that reacts with a hydroxyl group> The compound of formula (6) synthesized in Production Example 3 <(C) Ingredients: Other crosslinking agents> Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, JER828EL) [Example 1] A mixture of the benzoxazine compound obtained in Production Example 1 (0.2000 g) as component (A) and 2-methylresorcinol (0.0219 g), a compound containing two or more phenolic hydroxyl groups, and a crosslinking agent containing disulfide bonds obtained in Production Example 3 (0.0611 g) were mixed and heated at 80°C for 1 hour to obtain a homogeneous liquid composition. This composition was poured onto a Teflon® film and heated under a pressure of 1.4 MPa in a hot press (Mini Test Press 10, manufactured by Toyo Seiki Seisakusho Co., Ltd.) at 160°C for 2 hours and then at 200°C for 2 hours to obtain a cured product. The amount of component (B) was such that the epoxy groups were 0.5 times the equivalent amount of the phenolic hydroxyl groups contained in component (A).

[0108] [Example 2] A cured product was obtained in the same manner as in Example 1, except that the reaction product (0.2000 g) obtained in Production Example 2 was used as component (A), the amount of the crosslinking agent containing disulfide bonds obtained in Production Example 3 as component (B) was set to 0.0551 g, and the pressure was set to 0.3 MPa. The amount of component (B) was such that the epoxy groups were 0.5 times the equivalent amount of the phenolic hydroxyl groups contained in component (A).

[0109] [Comparative Example 1] A cured product was obtained in the same manner as in Example 1, except that component (B) was not used, bisphenol A type epoxy resin (0.0637 g) was used as component (C), the pressure was set to 1.8 MPa, and the heating conditions were 160°C for 2 hours, 200°C for 2 hours, and 210°C for 0.5 hours. Component (C) does not have bonds that can undergo bond exchange reactions. The amount of component (C) was such that the epoxy groups were 0.5 times the equivalent amount of phenolic hydroxyl groups contained in component (A).

[0110] The results obtained for Examples 1 and 2 and Comparative Example 1 are shown in Table 1 and Figures 2 to 4.

[0111] [Table 1] (summary) Table 1 and Figure 2 show that Examples 1 and 2, which used a crosslinking agent containing disulfide bonds obtained in Production Example 3 as component (B), have a higher cut repair rate than Comparative Example 1, which used bisphenol A type epoxy resin as the crosslinking agent instead of the crosslinking agent containing disulfide bonds. Furthermore, Table 1 and Figure 3 show that Examples 1 and 2 have a higher deformation rate (reformability) of the cured products by hot pressing than Comparative Example 1. In addition, Table 1 and Figure 4 show that Examples 1 and 2 have higher decomposition properties of the cured products than Comparative Example 1. Specifically, Figure 4 shows that when (±)-dithiothreitol is added, the cured products in Examples 1 and 2 become invisible to the naked eye, the color of the solution changes, and it can be seen that the cured products have almost completely decomposed, while in the Comparative Example, the cured products remain, the color change of the solution is minimal, and it can be seen that only partial decomposition has occurred. The reaction equation shown in Figure 4 is the reaction equation when the disulfide bonds in the cured product are cleaved by a reaction with (±)-dithiothreitol and converted to thiol groups, causing the cured product to decompose and dissolve in the solvent.

[0112] From the above, it can be seen that, in the present invention, the cured product of the composition containing the combination of component (A) and component (B) exhibits excellent self-healing properties, remolding properties, and degradability. [Industrial applicability]

[0113] The present invention can be suitably used in electronic materials such as electronic components, laminates for printed circuit boards and printed circuit boards, semiconductor encapsulation materials, and semiconductor mounting modules, as well as in automobiles or vehicles, aircraft parts, building materials, machine tools, and the like. [Explanation of symbols]

[0114] 1. Reaction Products 2 Crosslinking agent 3, 4, 5 Disulfide bonds

Claims

1. (A) Components: (i) a benzoxazine compound and (ii) a compound containing two or more phenolic hydroxyl groups, and / or a mixture of (i) and (ii), (B) Component: A crosslinking agent containing a bond capable of bond exchange reaction and a functional group that reacts with a hydroxyl group, The content of component (A) is 30 to 99% by weight, The ratio (X) / (Y) of the equivalent amount (X) of phenolic hydroxyl groups contained in component (A) to the equivalent amount (Y) of functional groups that react with the hydroxyl groups in component (B) is 0.25 or more and 5 or less. A benzoxazine composition in which the bond capable of the aforementioned bond exchange reaction is a disulfide bond.

2. (A) Component: The reaction product represented by the following formula (1), (B) Component: Contains a crosslinking agent represented by the following formula (2), The content of component (A) is 30 to 99% by weight, A benzoxazine composition in which the ratio (X) / (Y) of the equivalent amount (X) of phenolic hydroxyl groups contained in component (A) to the equivalent amount (Y) of functional groups that react with the hydroxyl groups of component (B) is 0.25 or more and 5 or less. 【Chemistry 1】 In equation (1), n ​​is an integer, and R １ R is an aromatic group, an aliphatic group, and / or multiple aliphatic groups linked via an ether bond. ２ ~R ５ Each of these independently represents one selected from the group consisting of halogen atoms, alkyl groups, alkyl halides, hydroxyl groups, carboxyl groups, amino groups, and alkoxy groups, R ６ and R ７ Each of these independently represents one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an alkyl halide, a hydroxyl group, a carboxyl group, an amino group, and an alkoxy group. 【Chemistry 2】 In formula (2), R ８ X is an aromatic group and / or an aliphatic group, and contains a disulfide bond capable of bond exchange reactions, and X and Y are each a functional group that reacts independently with a hydroxyl group.

3. The benzoxazine composition according to claim 1 or 2, wherein the functional group that reacts with the hydroxyl group is an epoxy group.

4. A cured product obtained by curing the benzoxazine composition according to claim 1 or 2.

5. The cured product according to claim 4, further comprising reinforcing fibers.

6. A method for repairing a hardened material, comprising the step of heating the hardened material according to claim 4.

7. A method for reshaping a cured product, comprising the step of heating and pressurizing the cured product according to claim 4.

8. A method for decomposing a cured product, comprising the step of heating the cured product according to claim 4 in a solvent containing a reducing agent.

9. A method for decomposing a cured product, comprising the step of heating the cured product according to claim 5 in a solvent containing a reducing agent to decompose the parts other than the reinforcing fibers.

10. A method for reusing a hardened material, comprising the step of recovering and reusing the decomposed products of the hardened material obtained by the decomposition method described in claim 8.

11. A method for reusing a cured material, comprising the step of recovering and reusing the decomposed product and reinforcing fibers of the cured material obtained by the decomposition method described in claim 9.

12. A prepreg or semipreg obtained by impregnating reinforcing fibers with the benzoxazine composition according to claim 1 or 2.

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