Modified bismaleimide resin and preparation method thereof

Abstract

To provide a modified bismaleimide resin with a lower water absorption rate, and a preparation method thereof.SOLUTION: The modified bismaleimide resin has a structure represented by [general formula] in the figure, where L is represented by [Formula A] in the figure or the like.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a maleimide resin, and in particular to a modified maleimide resin. [Background technology]

[0002] With the advancement of technology, electronic components are becoming lighter, thinner, shorter and smaller. Moreover, with the emergence of the 5th generation mobile communication technology (5th Generation Mobile Network, 5G) and even the 6th generation mobile communication technology (6th Generation Mobile Network, 6G), the industry demands for high frequency transmission, high speed signal transmission and low latency continue to grow. Therefore, in order to meet the requirements of dielectric properties (low dielectric constant, low dielectric loss tangent) and heat resistance in electronic substrates, related fields are working on developing substrate materials with high glass transition temperature (Tg), low dielectric constant (Dk), low dielectric loss tangent (Df) and good heat resistance.

[0003] General bismaleimide resins (mainly aliphatic molecular structures) have good processability, but may have poor moisture resistance and may not be usable or suitable for use in high-humidity or aqueous environments, and may not be applicable to high-end or special specification products. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a modified bismaleimide resin having lower water absorption (i.e., good moisture resistance) and a method for producing the same. [Means for solving the problem]

[0005] The modified bismaleimide resin according to the present invention has the following structural formula: [ka] L is represented by formula A, formula B, or formula C. [ka] In the formula, R1 is an alkyl group having 1 to 3 carbon atoms, and R2 is a substituted or unsubstituted alkyl group having 1 to 16 carbon atoms, a substituted or unsubstituted cycloalkyl group, or a substituted or unsubstituted aryl group. [ka]

[0006] The method for preparing the modified bismaleimide resin according to the present invention includes the steps of: mixing maleic anhydride and a bisamine compound to form a corresponding mixture; heating the mixture; and the bisamine compound having a backbone structure or fragment represented by Formula A, Formula B, or Formula C above. Effect of the Invention

[0007] Based on the above, the modified maleimide resin of the present invention has at least a specific main chain structure or fragment, and therefore has low water absorption (i.e., good moisture resistance), low thermal expansion coefficient and dielectric properties, and therefore has excellent applicability. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic flow chart showing a part of a method for producing a polyphenylene ether-type bismaleimide resin according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In the following detailed description, by way of example and not limitation, exemplary embodiments disclosing specific details are described to provide a thorough understanding of the various principles of the present invention. However, it will be apparent to those skilled in the art that, while benefiting from the present invention, the present invention may be practiced in other embodiments that depart from the specific details disclosed herein. Moreover, descriptions of commonly known devices, methods, and materials may be omitted so as not to distract from the description of the various principles of the present invention.

[0010] Ranges may be expressed herein as from "about" one particular value to "about" another particular value, which may be expressed directly as the one particular value and / or to the other particular value. When a range is expressed, another embodiment includes the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, by using the word "about," it is understood that the particular value forms another embodiment. It is further understood that the endpoints of each range may or may not be related to the other endpoint.

[0011] As used herein, non-limiting terms (e.g., "may," "can," "for example," or other similar terms) indicate a non-required or optional implementation, inclusion, addition, or presence.

[0012] As used herein, a "substituted" functional group or compound may mean that a non-reactive hydrogen atom in the functional group or compound may be replaced by an isotope or by a corresponding non-reactive group (e.g., an alkyl group).

[0013] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. Furthermore, terms (such as those defined in commonly used dictionaries) should be interpreted to have a meaning consistent with the meaning in the relevant technical context. It is also understood that unless expressly defined as such, they should not be interpreted in an idealized or overly formal sense.

[0014] [Preparation of modified maleimide resin] As shown in FIG. 1, in this embodiment, the method for producing a modified maleimide resin may include the following steps.

[0015] Step S10 involves mixing and pre-condensing maleic anhydride and a bisamine compound under nitrogen.

[0016] In one embodiment, the bisamine compound may first be mixed with a solvent to form a feed mixture.

[0017] In one embodiment, the solvent is selected from the group consisting of toluene, methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK), dimethylacetamide (DMAC), dimethylformamide (DMF), and propylene glycol monomethyl ether (PM). However, the present invention is not limited to the above examples. Considering the solubility of the corresponding bisamine compound, it is preferable to include a hydrophobic solvent or to directly use a hydrophobic solvent.

[0018] In one embodiment, the ratio of the bisamine compound in the raw material mixture is about 30% by weight to 60% by weight.

[0019] In one embodiment, the bisamine compound may be a primary amine compound.

[0020] In one embodiment, the bisamine compound may have a non-polar main chain structure represented by the following formula A. That is, the bisamine compound may be a bisamine compound having a fragment represented by the following formula A. [ka]

[0021] In formula 1, R1 may be the same or different, and may be an alkyl group having 1 to 3 carbon atoms (which may be written as C1 to C3).

[0022] In formula 1, R2 may be the same or different and may be a substituted or unsubstituted alkyl group having 1 to 16 carbons (which may be written as C1 to C16), a substituted or unsubstituted cycloalkyl group, or a substituted or unsubstituted aryl group (e.g., a phenyl group or a phenyl-containing group).

[0023] In one embodiment, the bisamine compound may include a non-polar main chain structure represented by the following formula A-1: ​​In one embodiment, the bisamine compound having a fragment represented by formula A-1 is one of the bisamine compounds having a fragment represented by formula A. [ka]

[0024] In one embodiment, the bisamine compound having a fragment represented by formula A-1 may include a bisamine compound represented by formula A-1-1: [ka]

[0025] In one embodiment, the bisamine compound may include a non-polar main chain structure represented by formula A-2: In one embodiment, the bisamine compound having a fragment represented by formula A-2 is one of the bisamine compounds having a fragment represented by formula A. [ka]

[0026] In one embodiment, the bisamine compound having a fragment represented by formula A-2 may include a bisamine compound represented by formula A-2-1: [ka]

[0027] In one embodiment, the bisamine compound may comprise a non-polar backbone structure represented by formula A-3: In one embodiment, the bisamine compound having a fragment represented by formula A-3 is one of the bisamine compounds having a fragment represented by formula A. [ka]

[0028] In one embodiment, the bisamine compound having a fragment represented by formula A-3 may include a bisamine compound represented by formula A-3-1: [ka]

[0029] In one embodiment, the bisamine compound may have a non-polar main chain structure represented by the following formula B. That is, the bisamine compound may be a bisamine compound having a fragment represented by the following formula B. [ka]

[0030] In one embodiment, the bisamine compound having a fragment represented by formula B may include a bisamine compound represented by formula B-1: [ka]

[0031] In one embodiment, the bisamine compound may have a non-polar main chain structure represented by the following formula C. That is, the bisamine compound may be a bisamine compound having a fragment represented by the following formula C. [ka]

[0032] In one embodiment, the bisamine compound having a fragment represented by formula C may include a bisamine compound represented by formula C-1: [ka]

[0033] Maleic anhydride is then added to the raw mixture.

[0034] In one embodiment, the number of moles of the bisamine compound is about 2 to 3 times the number of moles of common maleic anhydride. That is, the molar ratio of maleic anhydride to the bisamine compound is about 1:2 to 1:3. The maleic anhydride may be a maleic anhydride solution having a concentration of 30 to 40 weight percent.

[0035] After mixing the bisamine compound and maleic anhydride, the bisamine compound and maleic anhydride can carry out a pre-condensation reaction at room temperature under a nitrogen atmosphere.

[0036] In one embodiment, the reaction rate of the pre-condensation reaction can be increased by adding a catalyst. In one embodiment, before mixing the bisamine compound and maleic anhydride, the corresponding catalyst can be added to the raw material mixture. In one embodiment, after mixing the bisamine compound and maleic anhydride, the corresponding catalyst can be added all at once or stepwise at an appropriate timing and in an appropriate amount according to the reaction conditions.

[0037] In one embodiment, the catalyst may include triphenylphosphine (TPP; CAS: 603-35-0). In one embodiment, the catalyst is added in an amount of about 7 to 10% by weight in the raw material mixture.

[0038] In one embodiment, the reaction rate or reactivity of the pre-condensation reaction (e.g., the corresponding ring-closing reaction) can be increased by adding a dehydrating agent. In one embodiment, after mixing the bisamine compound and maleic anhydride, the corresponding dehydrating agent can be added all at once or stepwise at a suitable timing and in a suitable amount according to the reaction conditions.

[0039] In one embodiment, the dehydrating agent may include 4-methylbenzenesulfonic anhydride (PTS / PTSA; CAS: 104-15-4).

[0040] Step S20 includes a heating reaction, which is a step of heating the mixture (for example, a mixture containing a bisamine compound and maleic anhydride, or further containing the initial product after the pre-condensation reaction thereof) in a thermostatic stirring reactor.

[0041] In one embodiment, the heating step may include heating from room temperature to a set temperature (approximately 90° C. to 150° C.).

[0042] In one embodiment, this step can be continued for about 10 hours to about 20 hours within a set temperature range to allow sufficient reaction and obtain a viscous resin composition containing the modified maleimide resin (i.e., step S30).

[0043] The structural formula of the modified maleimide resin formed by the above method can be represented by the following general formula: [ka]

[0044] In the general formula, L can be of formula A, formula B, or formula C above, depending on the type of bisamine compound used.

[0045] For example, when the bisamine compound used is a bisamine compound having a main chain structure represented by formula A, the modified maleimide resin formed may have a main chain structure represented by formula A. For example, the structural formula of the modified maleimide resin may include a structure represented by formula 1 below. [ka]

[0046] In formula 1, R1 and R2 are defined as above.

[0047] Specifically, taking the bisamine compound having the main chain structure represented by formula A-1 as an example, the modified maleimide resin formed may have a main chain structure represented by formula A.

[0048] Taking the bisamine compound used in formula A-1-1 as an example, the modified maleimide resin formed may include a structural formula represented by the following formula 2: [ka]

[0049] Taking the bisamine compound used in formula A-2-1 as an example, the modified maleimide resin formed may include a structural formula represented by the following formula 3: [ka]

[0050] Taking the bisamine compound used in formula A-3-1 as an example, the modified maleimide resin formed may include a structural formula represented by the following formula 4: [ka]

[0051] Taking the bisamine compound used in formula B-1 as an example, the modified maleimide resin formed may include a structural formula represented by formula 5 below: [ka]

[0052] Taking the bisamine compound used in formula C-1 as an example, the modified maleimide resin formed may include a structural formula represented by formula 6 below: [ka]

[0053] Based on the modified maleimide resin disclosed in the above embodiment, compared with the conventional maleimide resin (i.e., the unmodified maleimide resin different from the modified maleimide resin of the present invention), the present invention carries out a corresponding reaction between a specific bisamine compound and maleic anhydride, and replaces the main chain structure of the conventional maleimide resin with the non-polar main chain structure of the bisamine compound. In this way, the modified maleimide resin formed can still have the same or similar low dielectric constant and / or low dielectric loss properties. Furthermore, due to the chain type and / or non-polar structure of the non-polar main chain structure of the bisamine compound, the modified maleimide resin can have a tendency to have a corresponding main chain type and / or to have non-polar properties, which can improve the free volume and non-polar regions of the overall structure of the modified maleimide resin (such as reducing the influence of polar functional groups). Therefore, the modified maleimide resin can have a lower water absorption rate and / or a lower coefficient of thermal expansion (CTE).

[0054] In one embodiment, the number average molecular weight (Mn) of the modified maleimide resin may range from about 400 g / mol to about 700 g / mol, more preferably from about 450 g / mol to about 600 g / mol.

[0055] In one embodiment, the glass transition temperature (Tg) of the modified maleimide resin may range from about 150°C to about 300°C.

[0056] In one embodiment, the dielectric constant (Dk) of the modified maleimide resin may range from about 2.5 to about 3.5.

[0057] In one embodiment, the dielectric loss tangent (Df) of the modified maleimide resin may range from about 0.0035 to about 0.0065.

[0058] In one embodiment, the water absorption of the modified maleimide resin may be about 3.4% or less, preferably about 3.1% or less, more preferably about 2.5% or less, even more preferably about 1.6% or less, and even more preferably about 0.5% or less.

[0059] In one embodiment, the free volume of the modified maleimide resin is about 1850 Angstroms. 3 ~About 3000 Angstroms 3 The range may be:

[0060] In one embodiment, the modified maleimide resin can be applied to the manufacture of electronic components (e.g., copper foil substrates). For example, the modified maleimide resin can be applied to the dielectric material of the electronic components (e.g., the dielectric material of the copper foil substrate).

[0061] [Examples and Comparative Examples] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0062] The modified maleimide resins can be prepared by the methods described above, with the main difference in each example being the use of different bisamine compounds.

[0063] Example 1 is a modified maleimide resin formed from a bisamine compound represented by formula C-1. The modified maleimide resin may include a structural formula represented by formula 6.

[0064] Example 2 is a modified maleimide resin formed from a bisamine compound represented by formula B-1. The modified maleimide resin may include a structural formula represented by formula 5.

[0065] Example 3 is a modified maleimide resin formed from a bisamine compound represented by formula A-3-1. The modified maleimide resin may include a structural formula represented by formula 4.

[0066] Example 4 is a modified maleimide resin formed from a bisamine compound represented by formula A-2-1. The modified maleimide resin may include a structural formula represented by formula 3.

[0067] Example 5 is a modified maleimide resin formed from a bisamine compound represented by formula A-1-1. The modified maleimide resin may include a structural formula represented by formula 2.

[0068] The produced modified maleimide resin or a resin composition containing the produced modified maleimide resin can be applied to the production of copper foil substrates.

[0069] In Comparative Example 1, a commercially available bismaleimide resin composition (e.g., manufactured by K.I. Kasei Co., Ltd., product name BMI, weight average molecular weight of the entire resin composition is about 385) was used as is. This contains an unmodified maleimide resin (e.g., 4,4'-Diphenylmethane bismaleimide, CAS: 13676-54-5).

[0070] The method for producing the copper foil substrate will be described in detail below.

[0071] The modified maleimide resins of the above examples and the maleimide resins of the comparative examples were mixed in the same compounding ratio to prepare a resin varnish composition, and a copper foil substrate was produced by a conventional method. A conventional method for producing a copper foil substrate may include the following. After impregnating a 2116 glass fiber cloth with the above resin varnish composition, it is dried for several minutes under a condition of about 170°C (impregnation machine temperature), and the drying time is adjusted and controlled to obtain a dried prepreg having a melt viscosity of about 4000 to 12000 poise. Next, a lamination process is performed by laminating four prepregs between two copper foils having a thickness of about 35 μm.

[0072] The conditions / steps of the lamination process are shown below.

[0073] Step 1: The temperature is increased from about 80° C. to about 195° C. at a rate of about 0.5 hours (also may be written as 85° C.→195° C., 0.5 hours).

[0074] Step 2: Increase the pressure to about 7 kg / cm for about 0.5 hours. 2 from about 25kg / cm 2 (7kg / cm 2 →25kg / cm 2 , or 0.5 hours).

[0075] Step 3: Temperature: approx. 195°C, pressure: approx. 25kg / cm 2 Press for about 2.0 hours under the conditions of 195℃ / 25kg / cm 2 , or 2.0 hours).

[0076] Corresponding tests (eg, dielectric constant (Dk) test or dielectric loss tangent (Df) test) were carried out on the corresponding copper foil substrates produced.

[0077] The properties of the modified maleimide resins of the examples and the unmodified maleimide resin of the comparative example are shown in Table 1 below. In addition, for the sake of simplicity, the electrical property tests of copper foil substrates manufactured using modified and unmodified maleimide resins are also listed directly in Table 1.

[0078] [Table 1]

[0079] For each test method, a method commonly used in general resin-related techniques can be adopted, and examples will be described below.

[0080] Number-average molecular weight (Mn): Modified or unmodified maleimide resins were analyzed using gel permeation chromatography (GPC) and calibrated with molecular weight polystyrene standards.

[0081] Glass transition temperature (Tg) test: A differential scanning calorimeter (DSC) was used to analyze modified and unmodified maleimide resins at a heating rate of about 20°C / min. For most maleimide resin materials, the glass transition temperature and the thermal expansion coefficient are slightly negatively correlated. Therefore, when comparing two different maleimide resin materials, if the glass transition temperature of one type is higher than that of the other type, it can be inferred that the thermal expansion coefficient of one type is lower than that of the other type.

[0082] Dielectric constant test: The test method involves taking a test piece of approximately 5 cm x 5 cm square from the copper foil board after removing the copper foil, baking it in an oven at approximately 105°C for approximately 2 hours, measuring the thickness with a thickness meter, and then clamping the test piece to an impedance analyzer (Agilent E4991A) to measure the dielectric constant Dk data at three points and taking the average value.

[0083] Dissipation factor test: The test method involves taking a test piece of approximately 5 cm x 5 cm square from the copper foil board after removing the copper foil, baking it in an oven at approximately 105°C for approximately 2 hours, measuring the thickness with a thickness gauge, and then clamping the test piece to an impedance analyzer (Agilent E4991A) to measure the dissipation factor Df at three points and taking the average value.

[0084] Water absorption test: Modified or unmodified maleimide resin was placed in a constant temperature and humidity box and left for 5 minutes under conditions of a temperature of about 85°C and a humidity of about 85%, and the water absorption was measured. The water absorption rate is calculated by [difference in weight of the test piece before and after placing it in a pressure cooker] ÷ [initial weight of the test piece] × 100%.

[0085] Free volume (unit: angstrom) 3 ): It can be simulated and estimated using common commercial software (e.g., Materials Studio / BIOVIA Materials Studio, other similar software includes, but is not limited to, Chemistry at HARvard Macromolecular Mechanics (CHARMm)). For simulation and estimation methods, please refer to the official help tutorials of the corresponding software, and we will not explain them in detail here. For most maleimide resin materials, the free volume and water absorption rate are slightly negatively correlated. Therefore, when comparing two types of maleimide resin materials, if the free volume of one is larger than the free volume of the other, it can be inferred that the water absorption rate of one type is lower than that of the other type. Therefore, if a water absorption test of the maleimide resin material has not yet been performed (for example, it is only in the evaluation stage and substantial synthesis has not yet been performed), the water absorption rate can be evaluated by the above simulation method.

[0086] As shown in Table 1, compared with commercially available maleimide resins (as shown in the Comparative Examples) commonly used in the manufacture of electronic components, the modified maleimide resins of the present invention are comparable in terms of electrical properties (e.g., ultra-low loss level of circuit boards in terms of dielectric loss tangent (Df) is 0.0030-0.0065). Moreover, as shown in Example 1, the corresponding dielectric loss tangent can be even lower.

[0087] As shown in Table 1, compared with commercially available maleimide resins (as shown in the Comparative Examples) commonly used in the manufacture of electronic components, the modified maleimide resins of the present invention may have a lower capacitance effect (e.g., a smaller dielectric constant (Dk)) in terms of electrical properties.

[0088] As shown in Table 1, the thermal expansion coefficient of the modified maleimide resin of the present invention is comparable to that of commercially available maleimide resins commonly used in the manufacture of electronic components (as shown in the Comparative Examples). Moreover, the corresponding thermal expansion coefficients can be even lower, as shown in Examples 1 to 4. Moreover, the thermal expansion coefficients of the modified maleimide resin of the present invention can be even lower, as shown in Examples 1 to 4. Thus, the modified maleimide resin of the present invention is more suitable for the manufacture or use of electronic components.

[0089] As shown in Table 1, the modified maleimide resin of the present invention can have a lower water absorption rate, and therefore is more suitable for the manufacture or use of electronic components.

[0090] In summary, the modified maleimide resin of the present invention has at least a specific main chain structure or fragment, and therefore has low water absorption (i.e., good moisture resistance), low thermal expansion coefficient and dielectric properties, and therefore has excellent applicability. [Industrial Applicability]

[0091] Furthermore, the bismaleimide resins formed by the methods for producing bismaleimide resins described in the embodiments of the present invention can be applied directly or indirectly to copper foil substrates and further processed into other consumer, industrial, or suitable electronic products. [Explanation of symbols]

[0092] S10, S20, S30: Process

Claims

1. A modified bismaleimide resin having the following structural formula: 【Chemistry 1】 In the formula, L is represented by the following formula A, formula B, or formula C: 【Chemistry 2】 In the formula, R １ is an alkyl group having 1 to 3 carbon atoms, R ２ is a substituted or unsubstituted alkyl group having 1 to 16 carbon atoms, a substituted or unsubstituted cycloalkyl group, or a substituted or unsubstituted aryl group. 【Chemistry 3】

2. The modified bismaleimide resin according to claim 1, wherein formula A is represented by the following formula A-1: 【Chemistry 4】

3. The modified bismaleimide resin according to claim 1, wherein formula A is represented by the following formula A-2: 【Chemistry 5】

4. The modified bismaleimide resin according to claim 1, wherein formula A is represented by the following formula A-3: 【Chemistry 6】

5. 2. The modified bismaleimide resin of claim 1 having a water absorption of about 3.4% or less.

6. mixing maleic anhydride and a bisamine compound to form a corresponding mixture; and heating the mixture, wherein the bisamine compound has a main chain structure or fragment represented by Formula A, Formula B, or Formula C: 【Chemistry 7】 In the formula, R １ is an alkyl group having 1 to 3 carbon atoms, R ２ is a substituted or unsubstituted alkyl group having 1 to 16 carbon atoms, a substituted or unsubstituted cycloalkyl group, or a substituted or unsubstituted aryl group. 【Chemistry 8】

7. The method for producing a modified bismaleimide resin according to claim 6, wherein the mixing of the maleic anhydride and the bisamine compound is carried out at room temperature.

8. The method for producing a modified bismaleimide resin according to claim 6 , wherein the mixing of the maleic anhydride and the bisamine compound is carried out under a nitrogen atmosphere.

9. The method for producing a modified bismaleimide resin according to claim 6, wherein the mixture is heated to a temperature of 90°C to 150°C.

10. The method for producing a modified bismaleimide resin according to claim 6, wherein the heating of the mixture is continued for 10 to 20 hours.

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