MODIFIED BISMALEIMIDE RESIN, METHOD FOR PREPARING THE SAME, PREPREG, COPPER CLAD LAMINATE AND PRINTED CIRCUIT BOARD

Abstract

A modified bismaleimide resin, a method for preparing the same, a prepreg, a copper clad laminate, and a printed circuit board are provided. The modified bismaleimide resin is formed by a reaction between a diamine compound having a nonpolar backbone structure and maleic anhydride, and a molecular structure thereof contains a greater amount of non-polar and hydrophobic groups.

Claims

1. A modified bismaleimide resin, characterized by having a structure represented by formula (1): ##STR00007## wherein in formula (1), X and Y each independently represent a group represented by formula (2) or (3), Z represents a group represented by formula (4), (5) or (6), and n represents an integer from 1 to 20; ##STR00008## wherein R.sub.1 in formula (2) and R.sub.4 in formula (3) each independently represent a benzyl group or an alkyl group having 1 to 10 carbon atoms, and R.sub.2 and R.sub.3 in formula (2) and R.sub.5 and R.sub.6 in formula (3) each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

2. The modified bismaleimide resin according to claim 1, wherein the modified bismaleimide resin has a dielectric constant (Dk) of less than 2.6 and a dissipation factor (Df) of less than 0.003 at 10 GHz.

3. The modified bismaleimide resin according to claim 1, wherein a water absorption rate of the modified bismaleimide resin is from 0.1% to 0.3%.

4. The modified bismaleimide resin according to claim 1, wherein the modified bismaleimide resin has a solubility in acetone of 42% and a solubility in butanone of 40%.

5. A prepreg obtained by applying a resin material that includes the modified bismaleimide resin as claimed in claim 1 onto a substrate and curing the resin material.

6. A copper clad laminate, comprising the prepreg as claimed in claim 5 and a copper foil layer attached to the prepreg.

7. A printed circuit board obtained by patterning the copper foil layer of the copper clad laminate as claimed in claim 6 into a circuit.

8. A method for preparing the modified bismaleimide resin as claimed in claim 1, comprising: providing a reactor; placing a reaction solution into the reactor, wherein the reaction solution includes a diamine compound, maleic anhydride, and a solvent, and a molar ratio of the diamine compound to the maleic anhydride is 1:2-20; and adding a catalyst into the reaction solution to carry out a synthesis reaction between the diamine compound and the maleic anhydride.

9. The method according to claim 8, wherein the diamine compound has a structure represented by formula (7), (8), (9), (10), or (11): ##STR00009##

10. The method according to claim 8, wherein the synthesis reaction is carried out from 40° C. to 200° C. for 1 to 8 hours.

11. The method according to claim 8, wherein the solvent is acetone, toluene, N,N-dimethylformamide (DMF) or methyl isobutyl ketone (MIBK), and the catalyst includes sodium acetate, acetic anhydride and triethylamine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The described embodiments may be better understood by reference to the following description and the accompanying drawings, in which:

[0023] FIG. 1 is a flowchart of a method for preparing a modified bismaleimide resin of the present disclosure;

[0024] FIG. 2 is a schematic view showing a manufacturing process of a prepreg of the present disclosure;

[0025] FIG. 3 is a schematic view showing a structure of the prepreg of the present disclosure;

[0026] FIG. 4 is a schematic view showing a manufacturing process of a copper clad laminate of the present disclosure; and

[0027] FIG. 5 is a schematic view showing a structure of a printed circuit board of the present disclosure.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0028] The present disclosure is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. Like numbers in the drawings indicate like components throughout the views. As used in the description herein and throughout the claims that follow, unless the context clearly dictates otherwise, the meaning of “a”, “an”, and “the” includes plural reference, and the meaning of “in” includes “in” and “on”. Titles or subtitles can be used herein for the convenience of a reader, which shall have no influence on the scope of the present disclosure.

[0029] The terms used herein generally have their ordinary meanings in the art. In the case of conflict, the present document, including any definitions given herein, will prevail. The same thing can be expressed in more than one way. Alternative language and synonyms can be used for any term(s) discussed herein, and no special significance is to be placed upon whether a term is elaborated or discussed herein. A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification including examples of any terms is illustrative only, and in no way limits the scope and meaning of the present disclosure or of any exemplified term. Likewise, the present disclosure is not limited to various embodiments given herein. Numbering terms such as “first”, “second” or “third” can be used to describe various components, signals or the like, which are for distinguishing one component/signal from another one only, and are not intended to, nor should be construed to impose any substantive limitations on the components, signals or the like.

[0030] In order to improve properties of a bismaleimide resin for purposes of meeting practical requirements, the present disclosure modifies the bismaleimide resin. More specifically, the present disclosure uses a diamine compound having a nonpolar backbone structure to react with maleic anhydride in a synthesis reaction, and a modified bismaleimide resin thus obtained has a structure represented by formula (1):

##STR00004##

in formula (1), X and Y each independently represent a group represented by formula (2) or (3), Z represent a group represented by formula (4), (5) or (6), and n represents an integer from 1 to 20;

##STR00005##

R.sub.1 in formula (2) and R.sub.4 in formula (3) each independently represent a benzyl group or an alkyl group having 1 to 10 carbon atoms, and R.sub.2 and R.sub.3 in formula (2) and R.sub.5 and R.sub.6 in formula (3) each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

[0031] It should be noted that, the modified bismaleimide resin is a linear polymer, and a molecular structure thereof contains a greater amount of non-polar and hydrophobic groups, thus improving certain properties (such as brittleness, toughness, solvent solubility, electrical properties, and water absorbency). It is confirmed by experiments that, the modified bismaleimide resin has a solubility in acetone of 42% and a solubility in butanone of 40%. Furthermore, the modified bismaleimide resin has a dielectric constant (Dk) of less than 2.6 and a dissipation factor (Df) of less than 0.003 at 10 GHz. In addition, a water absorption rate of the modified bismaleimide resin is 0.1% to 0.3%.

[0032] Referring to FIG. 1, the modified bismaleimide resin of the present disclosure is prepared by the following steps: providing a reactor in step S1; placing a reaction solution into the reactor in step S2, where the reaction solution includes a diamine compound having a nonpolar backbone structure and maleic anhydride; and adding a catalyst into the reaction solution to carry out a synthesis reaction between the diamine compound and the maleic anhydride in step S3.

[0033] More specifically, the reactor can have a stirring mixer disposed therein for stirring the reaction solution, and ingredients in the reaction solution are therefore mixed together. When preparing the reaction solution, the diamine compound and the maleic anhydride can be dissolved in a solvent that is preferably a polar aprotic solvent, such as acetone, toluene, N,N-dimethylformamide (DMF) or methyl isobutyl ketone (MIBK). Preferably, a molar ratio of the diamine compound to the maleic anhydride is 1:2-20. The diamine compound has a structure represented by formula (7), (8), (9), (10), or (11):

##STR00006##

[0034] In step S3, the catalyst includes sodium acetate, acetic anhydride and triethylamine, and the diamine compound and the maleic anhydride undergo a Michael addition reaction in the presence of the catalyst. Reaction conditions include normal pressure, a reaction temperature from 40° C. to 200° C., and a reaction time from 1 to 8 hours. A bismaleamic acid is produced in the reaction solution after about 1 to 3 hours of reaction, and is then formed into a bismaleimide resin after the reaction is continued for another 1 to 5 hours. In practice, nitrogen gas can be introduced into the reactor before the initiation of the reaction, so as to remove air and moisture in the reactor. Furthermore, a dehydrating agent can be used in the reaction to remove water generated thereby, so as to increase a conversion rate of the reaction. The dehydrating agent can be a p-toluenesulfonate. However, the above description is only exemplary, and is not intended to limit the scope of the present disclosure.

[0035] After the reaction is completed, a weak base solution (such as a sodium bicarbonate aqueous solution) can be used to neutralize the reaction solution, and an alcohol is then used to precipitate resin particles or solution. Subsequently, the reaction solution is filtered and vacuum dried to obtain a powdered solid product of the bismaleimide resin.

Example 1

[0036] 164 g of a diamine compound having a structure represented by formula (7) (hereinafter referred to as “diamine compound A”) and 9.8 g of maleic anhydride are dissolved in 500 ml of toluene to prepare a reaction solution. A molar ratio of the diamine compound A to the maleic anhydride is 4:1. The reaction solution is placed into a 1000 ml four-neck round bottom reaction flask that has a stirring mixer disposed therein, and nitrogen gas is introduced into the 1000 ml four-neck round bottom reaction flask to remove air and moisture. The stirring mixer is turned on and operated at a rotation speed of 300 rpm under normal pressure, and the diamine compound A is fed in batches within half an hour.

[0037] A reaction temperature is raised to 60° C. to dissolve all the solids in the reaction solution. At this time, the reaction solution has a yellowish brown color. A catalyst including 4 g of sodium acetate, 140 ml of acetic anhydride, and 28 ml of triethylamine are added into the reaction solution. The reaction temperature is further raised to 90° C. to carry out a synthesis reaction between the diamine compound A and the maleic anhydride, and a reaction time is 8 hours. After the reaction is completed, the reaction solution is turned from the clear yellowish brown color into a viscous dark brown color. After a dark brown resin powder is precipitated from the reaction solution, impurities such as unreacted monomers and residuals of acid are removed from the dark brown resin powder, so that a high purity bismaleimide resin powder (hereinafter referred to as “BMI-A resin”) with a dark brown color is obtained. A physical property test is performed on a copper clad laminate made from the BMI-A resin, and test results are shown in Table 1.

Example 2

[0038] 147 g of a diamine compound having a structure represented by formula (8) (hereinafter referred to as “diamine compound B”) and 9.7 g of maleic anhydride are dissolved in 500 ml of N,N-dimethylformamide (DMF) to prepare a reaction solution. A molar ratio of the diamine compound B to the maleic anhydride is 4:1. The reaction solution is placed into a 1000 ml four-neck round bottom reaction flask that has a stirring mixer disposed therein, and nitrogen gas is introduced into the 1000 ml four-neck round bottom reaction flask to remove air and moisture. The stirring mixer is started and operated at a rotation speed of 300 rpm under normal pressure, and the diamine compound B is fed in batches within half an hour.

[0039] A reaction temperature is raised to 60° C. to dissolve all the solids in the reaction solution. At this time, the reaction solution has a yellowish brown color. A catalyst including 6 g of sodium acetate, 150 ml of acetic anhydride, and 30 ml of triethylamine are added into the reaction solution. The reaction temperature is further raised to 90° C. to carry out a synthesis reaction between the diamine compound B and the maleic anhydride, and a reaction time is 8 hours. After the reaction is completed, the reaction solution is turned from the clear yellowish brown color into a viscous dark brown color. After a dark brown resin powder is precipitated from the reaction solution, impurities such as unreacted monomers and residuals of acid are removed from the dark brown resin powder, so that a high purity bismaleimide resin powder (hereinafter referred to as “BMI-B resin”) with a dark brown color is obtained. A physical property test is performed on a copper clad laminate made from the BMI-B, and test results are shown in Table 1.

Example 3

[0040] 184 g of a diamine compound having a structure represented by formula (9) (hereinafter referred to as “diamine compound C”) and 12.38 g of maleic anhydride are dissolved in 450 ml of methyl isobutyl ketone (MIBK) to prepare a reaction solution. A molar ratio of the diamine compound C to the maleic anhydride is 4:1. The reaction solution is placed into a 1000 ml four-neck round bottom reaction flask that has a stirring mixer disposed therein, and nitrogen gas is introduced into the 1000 ml four-neck round bottom reaction flask to remove air and moisture. The stirring mixer is started and operated at a rotation speed of 300 rpm under normal pressure, and the diamine compound C is fed in batches within half an hour.

[0041] A reaction temperature is raised to 60° C. to dissolve all the solids in the reaction solution. At this time, the reaction solution has a yellowish brown color. A catalyst including 5 g of sodium acetate, 175 ml of acetic anhydride, and 35 ml of triethylamine are added into the reaction solution. The reaction temperature is further raised to 90° C. to carry out a synthesis reaction between the diamine compound C and the maleic anhydride, and a reaction time is 9 hours. After the reaction is completed, the reaction solution is turned from the clear yellowish brown color into a viscous reddish brown color. After a reddish brown resin powder is precipitated from the reaction solution, impurities such as unreacted monomers and residuals of acid are removed from the reddish brown resin powder, so that a high purity bismaleimide resin powder (hereinafter referred to as “BMI-C resin”) with a reddish brown color is obtained. A physical property test is performed on a copper clad laminate made from the BMI-C resin, and test results are shown in Table 1.

Example 4

[0042] 184 g of a diamine compound having a structure represented by formula (10) (hereinafter referred to as “diamine compound D”) and 15.54 g of maleic anhydride are dissolved in 300 ml of acetone to prepare a reaction solution. A molar ratio of the diamine compound D to the maleic anhydride is 4:1. The reaction solution is placed into a 1000 ml four-neck round bottom reaction flask that has a stirring mixer disposed therein, and nitrogen gas is introduced into the 1000 ml four-neck round bottom reaction flask to remove air and moisture. The stirring mixer is started and operated at a rotation speed of 300 rpm under normal pressure, and the diamine compound D is fed in batches within half an hour.

[0043] A reaction temperature is raised to 60° C. to dissolve all the solids in the reaction solution. At this time, the reaction solution has a yellowish brown color. A catalyst including 4 g of sodium acetate, 140 ml of acetic anhydride, and 28 ml of triethylamine are added into the reaction solution. The reaction temperature is further raised to 90° C. to carry out a synthesis reaction between the diamine compound D and the maleic anhydride, and a reaction time is 12 hours. After the reaction is completed, the reaction solution is turned from the clear yellowish brown color into a viscous reddish brown color. After a reddish brown resin powder is precipitated from the reaction solution, impurities such as unreacted monomers and residuals of acid are removed from the reddish brown resin powder, so that a high purity bismaleimide resin powder (hereinafter referred to as “BMI-D resin”) with a reddish brown color is obtained. A physical property test is performed on a copper clad laminate made from the BMI-D resin, and test results are shown in Table 1.

Example 5

[0044] 184 g of a diamine compound having a structure represented by formula (11) (hereinafter referred to as “diamine compound E”) and 17.47 g of maleic anhydride are dissolved in 430 ml of N,N-dimethylformamide (DMF) to prepare a reaction solution. A molar ratio of the diamine compound E to the maleic anhydride is 4:1. The reaction solution is placed into a 1000 ml four-neck round bottom reaction flask that has a stirring mixer disposed therein, and nitrogen gas is introduced into the 1000 ml four-neck round bottom reaction flask to remove air and moisture. The stirring mixer is started and operated at a rotation speed of 300 rpm under normal pressure, and the diamine compound E is fed in batches within half an hour.

[0045] A reaction temperature is raised to 60° C. to dissolve all the solids in the reaction solution. At this time, the reaction solution has a yellowish brown color. A catalyst including 4 g of sodium acetate, 140 ml of acetic anhydride, and 28 ml of triethylamine are added into the reaction solution. The reaction temperature is further raised to 90° C. to carry out a synthesis reaction between the diamine compound E and the maleic anhydride, and a reaction time is 10 hours. After the completion of the reaction, the reaction solution is turned into a viscous light yellow color from the clear yellowish brown color. Precipitating and purifying processes are performed on the reaction solution. After a light yellow resin powder is precipitated from the reaction solution, impurities such as unreacted monomers and residuals of acid are removed from the light yellow resin powder, so that a high purity bismaleimide resin powder (hereinafter referred to as “BMI-E resin”) with a light yellow color is obtained. A physical property test is performed on a copper clad laminate made from the BMI-E resin, and test results are shown in Table 1.

Comparative Example

[0046] A physical property test is performed on a copper clad laminate made from a conventional bismaleimide resin (product name. BMI-5100, available from Daiwakasei Industry Co. Ltd), and test results are shown in Table 1.

TABLE-US-00001 TABLE 1 Comparative Examples Example Items 1 2 3 4 5 (BMI-5100) Tg (°C) 215 255 274 204 213 225 Dk (10GHz) 2.55 2.58 2.81 2.54 2.38 2.65 Df (10GHz) 0.0027 0.0035 0.0031 0.0039 0.004 0.0041 Solvent solubility 60% 65% 70% 40% 40% 30% (%) Product appearance Dark Dark Reddish Reddish Light (Color of resin brown brown brown brown yellow particles)

[0047] In Table 1, the glass transition temperatures (Tg) are measured by a differential scanning calorimeter (TA 2100 DSC). The dielectric constants (Dk) and dissipation factors (Df) are measured by a dielectric analyzer (HP Agilent E4991A) at a frequency of 10 GHz. The solvent solubilities are measured by using acetone, and are represented by weight percentage.

[0048] Referring to FIG. 2 and FIG. 3, the modified bismaleimide resin of the present disclosure can be used to manufacture a prepreg 1. More specifically, a resin material 12 including the modified bismaleimide resin can be applied to a substrate 11 (e.g., an insulating paper, a glass fiber cloth, or another fiber material) in an appropriate manner, and the resin material 12 is dried to a semi-cured state. In practice, the resin material 12 may be in the form of a resin varnish, and may be applied in a coating or impregnating manner.

[0049] Referring to FIG. 4, the prepreg 1 can be used to manufacture a copper clad laminate C. More specifically, one or more copper foil layers 2 can be laminated on one or both sides of one or more of the prepregs 1, and then a hot pressing is performed. There are no particular restrictions on the hot pressing conditions (e.g., temperature and pressure), which can be adjusted according to a composition of the resin material 12.

[0050] Referring to FIG. 5, the copper clad laminate C can be used to manufacture a printed circuit board P. More specifically, the printed circuit board P can be manufactured by patterning the copper foil layer 2 of the copper clad laminate C into a circuit. That is, the copper foil layer 2 is formed into a circuit layer 2′ with a specific circuit pattern. The copper foil layer 2 may be patterned by lithography and etching, but is not limited thereto.

[0051] The foregoing description of the exemplary embodiments of the disclosure has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching.

[0052] The embodiments were chosen and described in order to explain the principles of the disclosure and their practical application so as to enable others skilled in the art to utilize the disclosure and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present disclosure pertains without departing from its spirit and scope.