JP6948907B2 - Maleimide resin and its production method, maleimide resin composition and cured product - Google Patents

Description

The present invention relates to a maleimide resin, a composition containing the maleimide resin, a cured product thereof, and a method for producing the resin. The maleimide resin of the present invention and the maleimide resin composition using the same have improved toughness of the obtained cured product. Further, the maleimide resin of the present invention has excellent solubility in an organic solvent and can be easily dissolved uniformly in a solvent, and can be suitably used for, for example, manufacturing a laminated board.

The maleimide resin is derived from its rigid structure and gives a cured product having extremely excellent heat resistance by homopolymerization or combination with a compound having a double bond in the molecule. For this reason, maleimide resins are widely used in the fields of electrical and electronic parts, structural materials, adhesives, paints, and the like.

Especially in the field of electronic materials, heat-resistant resins are required due to lead freezing of solder, and in particular, in the field of heat-resistant laminated plates that require high heat resistance, dimensional stability, electrical characteristics, etc., bismaleimide A cured product using is used.

However, the above-mentioned bismaleimide has extremely low solubility in a general-purpose organic solvent, and it is necessary to use a high boiling point solvent such as N-methyl-2-pyrrolidone, dimethylacetamide, N, N, or dimethylformamide. In addition, a large amount of organic solvent is required for its dissolution. Therefore, when using an impregnated varnish prepared by dissolving bismaleimide in these solvents, a high temperature is required to remove the solvent. Further, the solvent tends to remain in the preprig prepared from this varnish, and voids are formed on the laminated board, which causes poor insulation. For that reason, it is desirable that bismaleimide be well soluble in at least a low boiling point solvent such as methyl ethyl ketone.

Further, it is known that the toughness of the obtained cured product is insufficient due to the rigid structure of bismaleimide, and a brittle cured product is given, and improvement of the toughness is desired.

To improve the solvent solubility or toughness of bismaleimide, a method of prepolymerizing an existing bismaleimide compound and a diamine compound by a Michael addition reaction has been proposed (Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-241300

However, this prepolymer composed of a bismaleimide compound and a diamine compound has a problem that secondary amines remain in the structure and lacks thermal stability. That is, the secondary amine is activated by heating in the curing process or the like, and Michael addition is further promoted. This reaction is extremely reactive and gels before polymerization using the desired maleimide, so that the desired physical properties cannot be obtained, which is not preferable.

Therefore, an object of the present invention is to provide a maleimide resin which has good thermal stability, good solvent solubility, and gives a cured product having excellent heat resistance and good toughness at the time of curing.

As a result of diligent studies to solve the above problems, the present inventors have made a tertiary amine of a prepolymer composed of a bismaleimide compound and a diamine compound protected by a specific protective agent, thereby achieving high thermal stability. He discovered that it gives sex and completed the present invention.

Therefore, the present invention provides a maleimide resin represented by the following general formula (1).

（式中、Ｘはそれぞれ独立に、少なくとも１個以上の芳香族基を含み、５０個以下の炭素原子を含む２価の基を表し、Ｙはそれぞれ独立に１個以上５０個以下の炭素原子を含む２価の基を表し、ｚはそれぞれ独立に、酸無水物残基又はハロゲン化物残基である１価の基を表し、ｎはそれぞれ独立に０〜２０の整数を表す。但しｎの平均値であるｎ’は０を超える値である。）

(In the formula, X independently represents a divalent group containing at least one aromatic group and containing 50 or less carbon atoms, and Y independently represents 1 or more and 50 or less carbon atoms. Represents a divalent group containing, z independently represents a monovalent group which is an acid anhydride residue or a halide residue, and n independently represents an integer of 0 to 20. The average value n'is a value exceeding 0.)

Further, the present invention comprises a maleimide compound having two maleimide groups in one molecule represented by the following general formula (2) and a diamine having two amino groups in one molecule represented by the following general formula (3). It comprises a step of reacting a compound with a maleimide resin represented by the following general formula (4), and a step of reacting the maleimide resin with a protective agent selected from an acid anhydride or a halide. , The method for producing a maleimide resin represented by the general formula (1) is provided.

（式中Ｘは少なくとも１個以上の芳香族基を含み、５０個以下の炭素原子を含む２価の基を表す。）

(X in the formula represents a divalent group containing at least one aromatic group and 50 or less carbon atoms.)

（式中Ｙは１個以上５０個以下の炭素原子を含む２価の基を表す。）

(Y in the formula represents a divalent group containing 1 or more and 50 or less carbon atoms.)

（式中Ｘ、Ｙ及びｎは一般式（１）と同じである。）

(X, Y and n in the formula are the same as the general formula (1).)

The present invention also provides a maleimide resin represented by the following general formula (1').

（式中、Ｘはそれぞれ独立に、少なくとも１個以上の芳香族基を含み、５０個以下の炭素原子を含む２価の基を表し、Ｙはそれぞれ独立に１個以上５０個以下の炭素原子を含む２価の基を表し、ｚはそれぞれ独立に、酸無水物残基又はハロゲン化物残基である１価の基を表し、ｎは１〜２０の整数を表す。）

(In the formula, X independently represents a divalent group containing at least one aromatic group and containing 50 or less carbon atoms, and Y independently represents 1 or more and 50 or less carbon atoms. Represents a divalent group containing, z represents a monovalent group independently of an acid anhydride residue or a halide residue, and n represents an integer of 1 to 20.)

According to the present invention, a maleimide resin having extremely good solvent solubility and excellent thermal stability by itself can be obtained. Further, a maleimide resin composition that gives a cured product having high heat resistance and excellent toughness by using the maleimide resin of the present invention is provided. Further, a prepreg made of the maleimide resin composition, a laminated plate, a semiconductor encapsulant, a cured product of the maleimide resin composition, a circuit substrate containing the cured product, and a semiconductor device are also provided.
Since the maleimide resin of the present invention has excellent solvent solubility and thermal stability as compared with conventional bismaleimide compounds or maleimide prepolymers, it can be suitably used in the production of prepregs and laminates via varnish. In addition, the obtained cured product has excellent heat resistance and toughness, so that it can be suitably used even in a harsh environment, and its industrial utility is extremely high.

6 is a GPC chart of the maleimide resin obtained in Example 1. 6 is a GPC chart of the maleimide resin obtained in Example 2. 6 is a GPC chart of the maleimide resin obtained in Example 3. It is a GPC chart of the maleimide resin obtained in Comparative Example 2. 6 is a GPC chart of the product obtained in Comparative Example 3.

Hereinafter, the present invention will be described based on the preferred embodiment thereof. <Maleimide resin>
The maleimide resin of the present invention is represented by the following general formula (1).

（式中Ｘはそれぞれ独立に、少なくとも１個以上の芳香族基を含み、５０個以下の炭素原子を含む２価の基を表し、Ｙはそれぞれ独立に１個以上５０個以下の炭素原子を含む２価の基を表し、ｚはそれぞれ独立に、酸無水物残基又はハロゲン化物残基である１価の基を表し、ｎはそれぞれ独立に０〜２０の整数を表す。但しｎの平均値であるｎ’は０を超える。）

(In the formula, X independently represents a divalent group containing at least one aromatic group and containing 50 or less carbon atoms, and Y independently represents 1 or more and 50 or less carbon atoms. Represents a divalent group containing, z independently represents a monovalent group which is an acid anhydride residue or a halide residue, and n independently represents an integer of 0 to 20, but the average of n. The value n'exceeds 0.)

The maleimide resin of the present invention contains a maleimide resin (compound) represented by the following general formula (1'). Hereinafter, the maleimide resin of the present invention corresponds to both the resin represented by the general formula (1) and the maleimide resin represented by the general formula (1'), unless otherwise specified.

（式中Ｘはそれぞれ独立に、少なくとも１個以上の芳香族基を含み、５０個以下の炭素原子を含む２価の基を表し、Ｙはそれぞれ独立に１個以上５０個以下の炭素原子を含む２価の基を表し、ｚはそれぞれ独立に、酸無水物残基又はハロゲン化物残基である１価の基を表し、ｎは１〜２０の整数を表す。）

(In the formula, X independently represents a divalent group containing at least one aromatic group and containing 50 or less carbon atoms, and Y independently represents 1 or more and 50 or less carbon atoms. Represents a divalent group containing, z independently represents a monovalent group that is an acid anhydride residue or a halide residue, and n represents an integer of 1 to 20).

In the maleimide resin of the present invention, each X is a divalent group containing at least one aromatic group and 50 or less carbon atoms independently. Examples of X include a group represented by the following general formula:-(AL1) _m-A-. Here, A may be the same or different, and an aromatic group in which a phenylene group, a naphthylene group, a biphenylene group, a diphenylene ether group or their hydrogen atoms are substituted with an alkyl group or an allyl group having 1 to 4 carbon atoms. Groups are preferred. L1 may be the same or different, and is directly bonded, -O-, -CR ¹ R ^2- (R ¹ and R ² are independently hydrogen atoms or alkyl groups having 1 or more and 4 or less carbon atoms, respectively. Alkyl groups having 1 to 20 carbon atoms are preferable. As m, for example, a number having 0 or more and making the number of carbon atoms of X 50 or less can be mentioned. The number of carbon atoms of X is preferably 6 or more and 40 or less, and more preferably 6 or more and 30 or less.
More specifically, X is, for example, a divalent group according to any one of the following formulas (a) to (e) from the viewpoint of heat resistance and toughness of the cured product using the maleimide resin of the present invention. Is preferable.

X is more preferably the group of (a), (c) or (e) above, and particularly preferably the group of (e).

In the maleimide resin of the present invention, Y independently represents a divalent group containing 1 to 50 carbon atoms. Examples of Y include hydrocarbon groups or aromatic groups that do not contain or contain heteroatoms. Although not limited, from the viewpoint of toughness of the cured product using the maleimide resin of the present invention, Y is preferably a branched chain, linear or cyclic aliphatic group, and the branched chain is used. It is more preferable that it is a linear aliphatic group having no chain or an aliphatic group having a branched chain, and it is more preferable that it is a linear aliphatic group. Examples of the aliphatic group include a saturated aliphatic group and an unsaturated aliphatic group. From the viewpoint of improving the solubility of the maleimide resin, lowering the melting point and improving the toughness of the cured product, Y is more preferably a divalent linear aliphatic group containing 4 or more and 8 or less carbon atoms. A divalent linear aliphatic group containing 7 or more carbon atoms is particularly preferable. As one of the most preferable embodiments, for example, Y is a divalent linear aliphatic group represented by _{− (CH 2} ) _{6 −.} The hydrogen atom of these groups may be substituted with a substituent. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, a phenyl group and the like.

In the maleimide resin of the present invention, z independently represents a monovalent group which is an acid anhydride residue or a halide residue.

Here, in z of the present invention, the acid anhydride residue refers to a partial structure other than the structure of the chemical bond formed between the acid anhydride and the nitrogen atom, which is a group derived from the acid anhydride.
The acid anhydride residue is not limited, but is preferably a carboxylic acid anhydride residue from the viewpoint of successfully obtaining the maleimide resin of the present invention, and has 2 or more and 20 carbon atoms. The following are preferable, and those of 2 or more and 10 or less are more preferable. Among them, -CO-CH _{3 (acetyl group), which is a residue of acetic anhydride, -CO-CH 2 -CH 3} , which is a residue of propionic anhydride, and -CO-CH, which is a residue of succinic anhydride. _2- CH _2- COOH, -CO-C = C-COOH which is a residue of maleic anhydride, or -CO-@-COOH which is a residue of phthalic acid anhydride (-@-has a benzene ring structure 2 A valent group- ( _{representing C 6} H ₄ )-) or a group in which the hydrogen atom in these groups is substituted with an alkyl group having 1 or more and 20 or less carbon atoms (particularly 1 or more and 10 or less carbon atoms). More preferred. Of these, -CO-CH ₃ (acetyl group) is particularly preferable.

Further, in z of the present invention, the halide residue refers to a partial structure other than the structure of the chemical bond formed between the halide and the nitrogen atom, which is a group derived from the halide.
The halide residues are, but are not limited to, these aliphatic groups, or these aliphatic groups, which are the residues of the halides of saturated or unsaturated aliphatic groups, from the viewpoint of successfully obtaining the maleimide resin of the present invention. It is preferably a residue of a carboxylic acid halide. The halide residue preferably has 2 or more and 20 or less carbon atoms, and more preferably 2 or more and 10 or less. Of these, it is more preferable that _{-CH 3} -CH = CH ₂ (allyl group), which is a residue of allyl halide, _{or -CO-CH 3} (acetyl group), which is a residue of acetyl halide.

In the maleimide resin of the present invention, z is bonded to a nitrogen atom and the nitrogen atom is used as a tertiary amine to stabilize the reactivity. Therefore, the maleimide resin of the present invention does not cause high molecular weight or gelation below the curing temperature, and is excellent in thermal stability. Moreover, the curing time can be easily adjusted.

In the maleimide resin of the present invention, it is preferable that z has a carbonyl group and has a structure in which it is bonded to a nitrogen atom to form an amide bond from the viewpoint of thermal stability of the maleimide resin. Specifically, _-CO-CH 3 _{(acetyl), - CO-CH 2 -CH} 3, -CO-CH 2 -CH 2 -COOH, -CO-C = C-COOH, -CO - @ - COOH (- @ - divalent group having a benzene ring structure - _(C 6 _{H 4)} - are expressed) more preferably, among others -CO-CH ₃ (acetyl group) is particularly preferred.

In the maleimide resin of the present invention, n represents the number of repetitions, and n in the general formula (1) independently represents an integer of 0 to 20. However, at least one (one molecule) of n is an integer of 1 or more.
That is, the maleimide resin of the present invention may be a pure substance composed of only a maleimide compound having n of 1 or more or a compound having the same n, but the maleimide represented by the general formula (1) is preferable. The resin is a mixture of various maleimide compounds (molecular species) having a number of repetitions n, which may contain a compound of n = 0. By containing a maleimide compound (molecular species) having n of 1 or more, this mixture becomes a soluble maleimide resin having extremely good solvent solubility.

The maleimide resin represented by the general formula (1) of the present invention preferably contains 90% or less of the component of n = 0 from the viewpoint of improving the solvent solubility of the maleimide resin itself, and n = The content of 0 is more preferably 85% or less, and particularly preferably 80% or less. Further, in the maleimide resin represented by the general formula (1), the component of n = 0 is preferably small from the viewpoint of solvent solubility, but it suppresses the increase in the molecular weight of the maleimide resin and is easy to handle during work. From the viewpoint of making the above excellent, for example, the component of n = 0 is preferably 5% or more, the component of n = 0 is more preferably 10% or more, and 15% or more. Especially preferable. The amount of n = 0 component can be determined by the method described in Examples described later.

The maleimide resin of the present invention is preferably an aggregate of polymers having various molecular weights, and the value of n can be expressed as an average value n'in the aggregate.
The average value n'is preferably 0.1 or more and 2.0 or less, more preferably 0.2 or more and 1.5 or less, and particularly preferably 0.2 or more and 1.0 or less. Solvent solubility can be further enhanced by setting the value of n'to the above lower limit or more. Further, by setting the value of n'to the above upper limit or less, it becomes advantageous in terms of handleability during work and the like. It is not easy to specify n of all the molecules represented by the formula (1) in the resin and take their arithmetic mean. Therefore, in the present invention, instead of taking this arithmetic mean, the area ratio corresponding to each n is obtained by gel permeation chromatography (GPC) analysis, and n'can be calculated based on this area ratio. Specifically, n'can be measured by the method described in Examples.

The Mw / Mn (dispersity), which is the ratio of the weight average molecular weight Mw to the number average molecular weight Mn of the maleimide resin of the present invention, is preferably 1.0 or more and 3.0 or less, and more preferably 1.1 or more and 2 It is less than or equal to 0.0. Solvent solubility can be further enhanced by setting the value of the number average molecular weight Mn to be equal to or higher than the above lower limit. Further, by setting the value of the number average molecular weight Mn to the above upper limit or less, it becomes advantageous in terms of handleability during work and the like. The weight average molecular weight Mw and the number average molecular weight Mn of the maleimide resin of the present invention can be obtained as polystyrene-equivalent values by gel permeation chromatography analysis, and can be obtained by the method described in the following Examples.

The maleimide resin of the present invention preferably has a melting point of 150 ° C. or lower by differential scanning calorimetry, and is 70 ° C. or higher and 150 ° C. or higher, from the viewpoint of excellent blocking resistance during storage, handleability during work, and the like. The temperature is more preferably 80 ° C or higher, and further preferably 80 ° C or higher and 110 ° C or lower. If it is lower than the above range, blocking occurs during storage, and if it is high, a high temperature is required during use, which is not preferable. This melting point can be determined by the method described in the examples below.

The maleimide resin of the present invention preferably has a softening point of 150 ° C. or lower, preferably 90 ° C. or higher, from the viewpoint of excellent blocking resistance during storage, handleability during work, and the like. It is more preferably 150 ° C. or lower, and further preferably 100 ° C. or higher and 140 ° C. or lower. When it is at least the above lower limit, it is preferable because it is easy to prevent blocking during storage, and when it is at least the above upper limit, it is preferable because it is easy to eliminate the need for high temperature during use.

In the present invention, the solvent solubility of the maleimide resin is preferably 50 g or more, more preferably 100 g or more, with respect to 100 g of methyl ethyl ketone at 25 ° C. It is preferable that the dissolved weight is at least the above lower limit because a large amount of solvent is not required during the production of the varnish, which is preferable from the viewpoint of economy, and the generation of voids and the like can be prevented in the production of the prepreg and the production of the laminated board using the prepreg. It is preferable from the point of view. It is preferable that the solvent solubility is as high as possible.

<Manufacturing method of maleimide resin>
The method for producing a maleimide resin of the present invention is:
A bismaleimide compound having two maleimide groups in one molecule represented by the following general formula (2),

（式中Ｘは、少なくとも１個以上の芳香族基を含み、５０個以下の炭素原子を含む２価の基を表す。）
下記一般式（３）で表される１分子中に２つのアミノ基を有するジアミン化合物と、

(X in the formula represents a divalent group containing at least one aromatic group and 50 or less carbon atoms.)
A diamine compound having two amino groups in one molecule represented by the following general formula (3) and

（式中Ｙは１個以上５０個以下の炭素原子を含む２価の基を表す。）を反応させて、下記一般式（４）で表される、分子中に２級アミン構造を有するマレイミド樹脂を得る工程と、

(Y in the formula represents a divalent group containing 1 or more and 50 or less carbon atoms.) Maleimide having a secondary amine structure in the molecule represented by the following general formula (4). The process of obtaining resin and

（式中Ｘ、Ｙ及びｎは一般式（１）と同じである。）
前記一般式（４）で表されるマレイミド樹脂と、酸無水物、又はハロゲン化物から選択される保護剤とを反応させることにより２級アミンを保護し、３級アミンへ変換する工程と、を含むことを特徴とする、下記一般式（１）で表されるマレイミド樹脂（及び上記一般式（１’）で表されるマレイミド樹脂）の製造方法である。

(X, Y and n in the formula are the same as the general formula (1).)
A step of protecting the secondary amine by reacting the maleimide resin represented by the general formula (4) with a protective agent selected from an acid anhydride or a halide, and converting the secondary amine into a tertiary amine. It is a method for producing a maleimide resin represented by the following general formula (1) (and a maleimide resin represented by the above general formula (1')), which comprises the above.

（式中Ｘはそれぞれ独立に、少なくとも１個以上の芳香族基を含み、５０個以下の炭素原子を含む２価の基を表し、Ｙはそれぞれ独立に１個以上５０個以下の炭素原子を含む２価の基を表し、ｚはそれぞれ独立に、酸無水物残基又はハロゲン化物残基である１価の基を表し、ｎはそれぞれ独立に０〜２０の整数を表す。但しｎの平均値であるｎ’は０を超える値である。）

(In the formula, X independently represents a divalent group containing at least one aromatic group and containing 50 or less carbon atoms, and Y independently represents 1 or more and 50 or less carbon atoms. Represents a divalent group containing, z independently represents a monovalent group which is an acid anhydride residue or a halide residue, and n independently represents an integer of 0 to 20, but the average of n. The value n'is a value exceeding 0.)

<Maleimide compound>
As the bismaleimide compound used in the method for producing a maleimide resin of the present invention, a bismaleimide compound having two maleimide groups in one molecule represented by the following general formula (2) is used.

（式中Ｘは、少なくとも１個以上の芳香族基を含み、５０個以下の炭素原子を含む２価の基を表す。）

(X in the formula represents a divalent group containing at least one aromatic group and 50 or less carbon atoms.)

The bismaleimide compound represented by the general formula (2) is not particularly limited, and examples thereof include a group giving an example as X in the maleimide resin of the present invention, and from the viewpoint of reactivity with diamine, it can be mentioned. An aromatic bismaleimide compound in which a maleimide group is bonded to an aromatic group is preferable. Specific examples include 4,4'-diphenylmethanebismaleimide, m-phenylenebismaleimide, 2,2-bis (4- (4-maleimidephenoxy) phenyl) propane, 4-methyl-1,3-phenylenebismaleimide, and Known bismaleimide compounds such as 3.3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide can be mentioned, and these can be used alone or in combination of two or more. .. From the viewpoint of improving the heat resistance and toughness of the cured product using the maleimide resin obtained by the method for producing the maleimide resin of the present invention, 2,2-bis (4- (4-maleimide phenoxy) represented by the following formula). Phenyl) propane is particularly preferred.

<Diamine compound>
As the diamine compound used in the method for producing the maleimide resin of the present invention, a diamine compound having two amino groups in one molecule represented by the following general formula (3) is used.

（式中Ｙは１個以上５０個以下の炭素原子を含む２価の基を表す。）

(Y in the formula represents a divalent group containing 1 or more and 50 or less carbon atoms.)

The diamine compound represented by the general formula (3) is not particularly limited, and examples thereof include groups giving the group exemplified as Y in the maleimide resin of the present invention, and specifically, diaminoethane, diaminopropane, and diamino. Butane, hexamethylenediamine, diaminooctane, diaminodecane, diaminododecane, m-xylenediamine p-xylenediamine, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl ether, 1,4 Various diamine compounds such as -bis (4-aminophenoxy) benzene and 2,2'-bis [4- (4-aminophenoxy) phenyl] propane can be mentioned, and these may be used alone or in combination of two or more. Can be used. From the viewpoint of improving the toughness of the cured product, improving the solubility of the maleimide resin and lowering the melting point, and the reactivity with the bismaleimide compound, it is preferable to use an aliphatic diamine, and hexamethylenediamine, which is a linear aliphatic diamine, is used. Especially preferable.

In the method for producing a maleimide resin of the present invention, a bismaleimide compound represented by the general formula (2) and a diamine compound represented by the general formula (3) are subjected to a Michael addition reaction and the following general formula (4) is used. The step (I) of obtaining a maleimide resin having a secondary amine structure in the represented molecule is included. In the step (I), usually, the bismaleimide compound represented by the general formula (2) and the diamine compound represented by the general formula (3) are uniformly dissolved in a solvent, and then in the presence or absence of a catalyst. The Michael addition reaction is carried out with a catalyst.

（式中Ｘ、Ｙ及びｎは一般式（１）と同じである。）

(X, Y and n in the formula are the same as the general formula (1).)

In the step (I) of obtaining a maleimide resin having a secondary amine structure in the molecule, the molar ratio of the bismaleimide compound represented by the general formula (2) to the diamine compound represented by the general formula (3) ( The number of moles with the diamine compound represented by the general formula (3) / the number of moles of the bismaleimide compound represented by the general formula (2)) is preferably 0.01 or more and 1.00 or less, and more. It is preferably 0.05 or more and 0.50 or less, more preferably 0.10 or more and 0.25 or less, and particularly preferably 0.12 or more and 0.25 or less. By setting the molar ratio within this range, the solvent solubility of the maleimide resin obtained by the method for producing the maleimide resin of the present invention, the blocking resistance during storage, the handleability during work, and the like can be improved. ..

In the step (I) of obtaining a maleimide resin having a secondary amine structure in the molecule, the solvent used is a solvent that dissolves maleimide or diamine, such as various organic solvents or phenols, and has no reactivity with these. If so, there is no particular limitation. As an example of the organic solvent, dioxane, dimethylformamide and the like can be used, and as the phenols, phenol, cresol and the like can be used. Preferred are dioxane and phenol.

In the step (I) of obtaining a maleimide resin having a secondary amine structure in the molecule, addition of a bismaleimide compound represented by the general formula (2), a diamine compound represented by the general formula (3), and a solvent. The order is not particularly limited, and it is sufficient that these can be mixed uniformly.

In the step (I) of obtaining a maleimide resin having a secondary amine structure in the molecule, a Michael addition reaction between the bismaleimide compound represented by the general formula (2) and the diamine compound represented by the general formula (3). Can be carried out in the presence of a catalyst or without a catalyst. When the reaction is carried out in the presence of a catalyst, the catalyst that can be used is not particularly limited, and known catalysts such as hydrochloric acid, oxalic acid, sulfuric acid, phosphoric acid, and p-toluenesulfonic acid should be used alone or in combination of two or more. However, sulfuric acid and p-toluenesulfonic acid are particularly preferable. The amount of catalyst used can be appropriately adjusted from the reactivity of the bismaleimide compound and the amine compound.

In the step (I) of obtaining a maleimide resin having a secondary amine structure in the molecule, a Michael addition reaction between the bismaleimide compound represented by the general formula (2) and the diamine compound represented by the general formula (3). The reaction temperature of the above is preferably room temperature (25 ° C.) to 150 ° C., more preferably room temperature to 80 ° C., and further preferably room temperature to 60 ° C. from the viewpoint of preventing high molecular weight and the like. The time of the addition reaction varies depending on the combination of bismaleimide and diamine, the solvent type, the catalyst type, etc., but is about 1 to 24 hours. The reaction pressure is usually carried out under normal pressure, but there is no problem even if it is carried out under slight pressurization or reduced pressure.

The method for producing a maleimide resin of the present invention is selected from a maleimide resin having a secondary amine structure in the molecule represented by the general formula (4) obtained in the step (I), an acid anhydride, or a halide. The step (II) of protecting the secondary amine and converting it into a tertiary amine is included by reacting with the protective agent.

By including the step (II) of protecting the secondary amine with this protective agent and converting it into the tertiary amine, the maleimide resin of the present invention does not cause high molecular weight or gelation below the curing temperature, and is thermally stable. Can be excellent.

<Protective agent>
In the method for producing a maleimide resin of the present invention, as a protective agent used for protection of a secondary amine, an acid anhydride or a halide can be used as a compound having a functional group that reacts with the secondary amine. The acid anhydride is not particularly limited, and examples thereof include those giving the group exemplified above as the acid anhydride residue of the maleimide resin of the present invention, specifically, acetic anhydride, propionic anhydride, succinic anhydride, and the like. Examples thereof include carboxylic acid anhydrides such as maleic anhydride, phthalic anhydride, and substituents such as alkyl groups thereof. Examples of the halide include those having the group exemplified above as the halide residue in the maleimide resin of the present invention, and specific examples thereof include acetyl chloride and allyl chloride. Particularly preferably, the protective agent is a carboxylic acid anhydride, and particularly preferably acetic anhydride.

The amount of the protective agent used is equal to the number of moles of the secondary amine contained in the structure of the maleimide resin represented by the general formula (4) obtained in the step (I). It is preferable to do so. Specifically, the ratio to (the number of moles of the protective agent / the number of moles of the secondary amine contained in the structure of the maleimide resin represented by the general formula (4)) is 1.0 or more and 3.0 or less. Is preferable, and 1.0 or more and 2.0 or less is more preferable. As for the amount of the protective agent used, it is preferable to use a protective agent having a number of moles equivalent to twice the number of moles of the diamine compound represented by the general formula (3) used in the step (I).

The step (II) of protecting the secondary amine with a protective agent and converting it to the tertiary amine can be carried out using the same solvent as the solvent used in the step (I).
Further, the reaction temperature in the step (II) of protecting the secondary amine with a protective agent and converting it to the tertiary amine is preferably room temperature (25 ° C.) to 150 ° C. from the viewpoint of preventing high molecular weight and the like. Is room temperature to 80 ° C., more preferably room temperature to 60 ° C. The reaction time varies depending on the combination of bismaleimide and diamine, the solvent type, and the protective agent used, but is about 1 to 24 hours. The reaction pressure is usually carried out under normal pressure, but there is no problem even if it is carried out under slight pressurization or reduced pressure.

The step (II) of protecting the secondary amine with a protective agent and converting it into a tertiary amine is performed in the same system following the step (I) of obtaining a maleimide resin having a secondary amine structure in the molecule. It is possible to do. From the viewpoint of manufacturing handling, it is preferable to carry out the protection reaction of step (II) after the Michael addition reaction of step (I).

The maleimide resin of the present invention represented by the general formula (1) is represented by the general formula (1) by removing the solvent and the acid catalyst after the reaction of the step (II) of protecting the secondary amine with a protective agent and converting it into a tertiary amine. Can be obtained. As a method for removing the solvent, it can be removed by reducing the pressure. When phenols are used as the solvent, the solvent is further heated while being blown with an inert gas or water vapor, and the phenols are distilled and removed from the system. It is common. The heating temperature at that time is preferably 150 ° C. or lower. Examples of the method for removing the acid catalyst include washing with water.

In the method for producing a maleimide resin of the present invention, a maleimide compound having excellent solvent solubility and a low melting point can be obtained by controlling the main chain structure of the raw material bismaleimide compound and diamine compound.

[Maleimide resin composition]
The maleimide resin of the present invention can give a cured product by heat polymerization alone, but can be combined with a known curing agent, curing accelerator, or the like to form a maleimide resin composition.

The maleimide resin composition of the present invention can contain a known curing agent. Known curing agents are not particularly limited, and examples thereof include compounds having one or more unsaturated double bond groups in one molecule. Examples of the compound having an unsaturated double-bonding group include, but are not limited to, 2,2'-diallyl bisphenol A, allylphenol resin, propenylphenol resin and the like. It is preferable to use an allyl phenol resin in consideration of workability and availability. As the allylphenol resin, those obtained by using allylphenol and various cross-linking agents can be used, but a resin obtained by allylating a phenol novolac resin with allyl halide or the like in the presence of a basic catalyst can also be used.

When the curing agent contains a compound in which the unsaturated double-bonding group is an allyl group, the content thereof is the number of maleimide group equivalents of the maleimide resin of the present invention and the number of allyl group equivalents of the compound having an allyl group. The ratio [maleimide group equivalent number / allyl group equivalent number] is preferably in the range of 0.80 to 2.00, more preferably 0.80 to 1.60.

The number of functional group equivalents such as the number of maleimide group equivalents and the number of allyl group equivalents is B / A (when the functional group equivalent is A (g / eq) and the charge amount is B (g). When the purity is C%, it can be determined by [B × C / 100] / A). That is, the functional group equivalents such as maleimide group equivalent and allyl group equivalent represent the molecular weight of the compound per functional group, and the functional group equivalent number is the number of functional groups (equivalent amount) per compound mass (charged amount). Represents a number).

Further, the maleimide resin of the present invention can be used in combination with an epoxy resin in the presence or absence of the compound having an unsaturated double bond group as long as the effect of the present invention is not impaired, and can be used as an epoxy resin. Is a glycidyl ether type epoxy resin such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, triphenol methane type epoxy resin, biphenyl type epoxy resin, glycidyl ester type epoxy resin, Examples thereof include epoxy resins having two or more epoxy groups in the molecule, such as glycidylamine type epoxy resins and halogenated epoxy type resins. These epoxy resins may be used alone or in combination of two or more.

Further, when the epoxy resin is used, a phenol resin can be used in addition to the above-mentioned compound having an unsaturated double bond group as long as the effect of the present invention is not impaired. As the phenol resin that can be used, one having two or more phenolic hydroxyl groups in the molecule obtained by the phenolic monomer and various cross-linking agents can be used. These phenol resins may be used alone or in combination of two or more.

The maleimide resin composition of the present invention (hereinafter, also referred to as “composition of the present invention”) can contain a curing accelerator. The curing accelerator may be any one that promotes the curing of the maleimide resin or, when the curing agent is contained, the curing of the maleimide resin and the curing agent, and generally includes those used as a radical initiator. Examples of such a curing accelerator include organic peroxides such as acyl peroxides, hydroperoxides, ketone peroxides, peroxides having a t-butyl group, and peroxides having a cumyl group. Can be done. For example, benzoyl peroxide, parachlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, capryl peroxide, lauroyl peroxide, acetyl peroxide, bis (1-hydroxycyclohexyl peroxide), Hydroxyheptyl peroxide, t-butyl hydroperoxide, p-methane hydroperoxide, cumene hydroperoxide, di-t-butyl peroxide, dicumyl peroxide (sometimes abbreviated as DCPO), 2,5- Dimethyl-2,5-di (t-butyl peroxide) hexane, 2,5-dimethylhexyl-2,5-di (peroxybenzoate), t-butyl perbenzoate, t-butyl peracetate, t-butyl per acetate Organic peroxides such as octoate, t-butylperoxyisobutyrate, and di-t-butyl-di-perphthalate can be mentioned, and one of these may be used alone or in combination of two or more. be able to. When a curing accelerator is used, the amount added thereof is preferably 0.01 part by mass or more and 10 parts by mass or less, and 1 part by mass or more and 8 parts by mass with respect to 100 parts by mass of the maleimide resin of the present invention in the composition of the present invention. Less than a part is more preferable.

Moreover, the maleimide resin composition of the present invention may contain other optional components. As such an optional component, depending on the use of the composition of the present invention, for example, additives such as a filler, an imidazole compound for promoting curing, a coupling agent, a pigment, and a dye can be preferably used. Further, a solvent such as an organic solvent can also be used.

As the filler, either an organic filler or an inorganic filler can be used. As the inorganic filler, for example, amorphous silica, crystalline silica, alumina, calcium silicate, calcium carbonate, talc, mica, barium sulfate and the like can be used. In particular, it is preferable to use amorphous silica and crystalline silica. The particle size of the inorganic filler is not particularly limited, but it is preferably 0.01 μm or more and 150 μm or less in consideration of the filling rate. The blending ratio of the inorganic filler is not particularly limited, but the proportion of the inorganic filler in the maleimide resin composition is preferably 70% by mass or more and 95% by mass or less, and is 70% by mass or more and 90% by mass or less. Is more preferable. It is preferable to set the blending ratio of the inorganic filler in this range because the water absorption rate of the cured product of the composition is less likely to increase.

The amount of the maleimide resin of the present invention in the maleimide resin composition of the present invention varies depending on the use of the composition of the present invention. For example, when the composition of the present invention does not contain a filler, the composition of the present invention contains. It is preferably 10% by mass or more and 90% by mass or less, and more preferably 30% by mass or more and 60% by mass or less. Further, for example, when the composition of the present invention contains a filler, the amount of the resin of the present invention is preferably 5% by mass or more and 25% by mass or less, preferably 5% by mass or more and 20% by mass or less in the composition of the present invention. Is more preferable.

The total amount of the components other than the maleimide resin, the curing agent, the curing accelerator, and the filler of the present invention in the maleimide resin composition of the present invention varies depending on the use of the composition of the present invention, but generally, of the present invention. It is preferably 15% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less with respect to the resin.

In order to prepare the composition of the present invention, for example, the maleimide resin of the present invention, and further, a curing agent, a curing accelerator, an inorganic filler, other additives, etc. to be added as needed are uniformly added using a mixer or the like. It may be mixed and kneaded in a molten state using a kneader such as a heating roll, a kneader or an extruder, and the kneaded product may be cooled and crushed if necessary.

The composition of the present invention can be suitably cured by a conventional heat treatment. For example, the heat treatment is affected by the presence or absence of a radical initiator or curing accelerator, but is preferably 150 to 280 ° C, more preferably 150 to 250 ° C, preferably 1 to 24 hours, more preferably 1 to 12. It is preferable to carry out under pressure for hours, under normal pressure or by using an autoclave or the like.

The maleimide resin of the present invention and the maleimide resin composition using the same are not particularly limited, but can be suitably used as a sealing material for sealing a semiconductor element by taking advantage of the heat resistance of the cured product. can. For example, after installing a lead frame or the like on which the semiconductor element is mounted in a metal cavity, the maleimide resin composition is molded by a molding method such as a transfer mold, a compression mold, or an injection mold, and at a temperature of about 120 ° C. to 300 ° C. A semiconductor device can be suitably obtained by curing the composition by performing heat treatment or the like.

Further, the maleimide resin of the present invention and the maleimide resin composition using the same can be uniformly dissolved in a known solvent such as methyl ethyl ketone, propylene glycol monomethyl ether and dimethylformamide to produce a varnish solution. A prepreg for a printed circuit board can be produced by applying or impregnating the varnish solution to a porous glass substrate such as glass, glass fiber, paper, aramid fiber, or the like, and then heat-treating (semi-curing) the prepreg. Further, a laminated board in which a matrix resin is formed using the composition of the present invention is preferable by laminating a plurality of the obtained prepregs for a printed circuit board and performing heat treatment while applying pressure as necessary to cure the prepreg. Can be manufactured in.
Further, as for the laminated board or prepreg, a metal-clad laminated board can be obtained by superimposing a metal foil on one side or both sides and performing heat treatment while applying pressure as necessary. This metal-clad laminate can be suitably used as a printed wiring board by forming a circuit pattern by etching treatment.

The maleimide resin of the present invention and the maleimide resin composition using the same are not particularly limited, but by taking advantage of the heat resistance of the cured product and the like, electric power such as a sealing material for a semiconductor element and a printed wiring substrate material, etc. In addition to electronic parts, it can be used as a structural material, adhesive, paint, etc.

Hereinafter, the present invention will be described in detail based on specific examples thereof, but the present invention is not limited to the following examples.

The analysis method and evaluation method used in the following examples of maleimide resin preparation will be described.
(1) Softening point equipment: Automatic drip point device METTLER TOLEDO FP83HT
Heating rate; 2 ° C / min.
(2) n = 0 component amount, Mw / Mn (molecular weight distribution): Calculated from the composition ratio obtained by gel permeation chromatography (GPC) analysis.
[GPC measurement conditions]
Equipment: Gel Permeation Chromatography (manufactured by Waters)
Columns: The following five SHODEX columns were used by connecting them in series from upstream to downstream in the following order.
KF-804 x 1
KF-803 x 1
KF-802.5 x 1
KF-802 x 1
KF-801 x 1
Moreover, one KF-G made by SHODEX was used as a guard column.
Column oven temperature: 40 ° C
Solvent: tetrahydrofuran (THF)
Flow rate: 1.00 mL / min Detector: Waters 2487 Dual λ Absorbance Detector
Detection wavelength: 254 nm
(3) Average value n': Can be obtained from the area ratio for each n number obtained by gel permeation chromatography (GPC) analysis.
{(N = 0 area ratio) x 0} + {(n = 1 area ratio) x 1} + {(n = 2 area ratio) x 2} + {(n = 3 area ratio) x 3} ... The average number of n can be obtained from the total value of. However, the total area ratio is 1.
(4) Maleimide equivalent: It can be obtained from the area ratio for each n number obtained by gel permeation chromatography (GPC) analysis and the maleimide equivalent for each n number.
For example, the maleimide equivalent of the maleimide resin represented by the general formula (1) is
[(N = 0 area ratio) × {maleimide equivalent of n = 0 (285 g / eq)}]
+ [(N = 1 area ratio) x {n = 1 maleimide equivalent (670 g / eq)}]
+ [(N = 2 area ratio) x {n = 2 maleimide equivalent (1055 g / eq)}]
+ [(N = 3 area ratio) x {n = 3 maleimide equivalent (1440 g / eq)}]
+ [(N = 4 area ratio) x {n = 4 maleimide equivalent (1825 g / eq)}]
It can be calculated by the total value of ... However, the total area ratio is 1.

[Synthesis of maleimide resin]
(Example 1)
In a four-necked flask equipped with a cooling tube and a stirrer, 2,2'-bis [4- (4-maleimide phenoxy) phenyl] propane 160.00 g (0.56 mol) as a bismaleimide compound and 1,6-hexa as a diamine. 8.14 g (0.14 mol) of methylenediamine and 640.00 g of phenol as a solvent were added, and the temperature was raised to 50 ° C. to uniformly dissolve the mixture. After dissolution, a Michael addition reaction was carried out at 50 ° C. for 1 hour to obtain a reaction solution containing a Michael adduct of bismaleimide and diamine. 28.63 g (0.28 mol) of acetic anhydride as a protective agent for the secondary amine was added to the obtained reaction solution containing the Michael adduct, and the protective reaction was carried out for 3 hours. After completion of the reaction, the reaction solution was heated to 150 ° C. to remove phenol under reduced pressure to obtain the maleimide resin (resin A) of the present invention. The softening point of the obtained maleimide resin was 135 ° C., and the n = 0 component by GPC analysis was 52%. The average value n'was 0.77, the weight average molecular weight Mw determined by polystyrene conversion was 1180, the number average molecular weight Mn was 697, and the molecular weight distribution (dispersity) Mw / Mn was 1.69. The maleimide equivalent was 586 g / eq. The GPC chart of the obtained maleimide resin is shown in FIG.

(Example 2)
The present invention is the same as in Example 1 except that 1,6-hexamethylenediamine as the diamine of Example 1 is 4.07 g (0.07 mol) and acetic anhydride as the protective agent is 14.32 g (0.14 mol). Maleimide resin (resin B) was obtained. The softening point of the obtained maleimide resin was 117 ° C., and the n = 0 component by GPC analysis was 72%. The average value n'was 0.37, the weight average molecular weight Mw determined by polystyrene conversion was 783, the number average molecular weight Mn was 572, and the molecular weight distribution (dispersity) Mw / Mn was 1.37. The maleimide equivalent was 425 g / eq. The GPC chart of the obtained maleimide resin is shown in FIG.

(Example 3)
The present invention is the same as in Example 1 except that 1,6-hexamethylenediamine as the diamine of Example 1 is 2.71 g (0.05 mol) and acetic anhydride as the protective agent is 10.20 g (0.10 mol). Maleimide resin (resin C) was obtained. The softening point of the obtained maleimide resin was 112 ° C., and the n = 0 component by GPC analysis was 82%. The average value n'was 0.23, the weight average molecular weight Mw determined by polystyrene conversion was 666, the number average molecular weight Mn was 533, and the molecular weight distribution (dispersity) Mw / Mn was 1.25. The maleimide equivalent was 361 g / eq. The GPC chart of the obtained maleimide resin is shown in FIG.

(Comparative Example 1)
In a four-necked flask equipped with a cooling tube and a stirrer, 2,2'-bis [4- (4-maleimide phenoxy) phenyl] propane 160.00 g (0.56 mol) as a bismaleimide compound and 1,6-hexa as a diamine. To add 640.00 g of phenol using 8.14 g (0.14 mol) of methylenediamine as a solvent, the temperature was raised to 50 ° C. and the mixture was uniformly dissolved. After dissolution, a Michael addition reaction was carried out at 50 ° C. for 1 hour to obtain a reaction solution containing a Michael adduct of bismaleimide and diamine. The reaction solution containing the obtained Michael adduct was heated to 150 ° C. and gelled in the process of removing phenol under reduced pressure, and no resin was obtained.

(Comparative Example 2)
The solvent of Comparative Example 1 was changed from phenol to tetrahydrofuran (THF), a reaction solution containing a Michael adduct was obtained under the same conditions, THF was removed under reduced pressure at 50 ° C., and a maleimide resin in which the secondary amine was not protected. (Resin D) was obtained. The n = 0 component of the obtained maleimide resin by GPC analysis was 52%. The average value n'was 0.85, the weight average molecular weight Mw determined by polystyrene conversion was 1240, the number average molecular weight Mn was 704, and the molecular weight distribution Mw / Mn of GPC was 1.76. The maleimide equivalent was 554 g / eq. The GPC chart of the obtained maleimide resin is shown in FIG. The softening point could not be measured because gelation occurred due to heating during the softening point measurement.

(Comparative Example 3)
In a three-necked flask equipped with a cooling tube and a stirrer, 8.14 g (0.14 mol) of 1,6-hexamethylenediamine as a diamine was dissolved in 40.00 g of phenol as a solvent, and 28.63 g (0.28 mol) of acetic anhydride as a protective agent was dissolved. ) Was added, and an acetylation reaction was carried out at room temperature for 3 hours to carry out a secondary amineation reaction of diamine. To the obtained reaction solution containing the secondary amine, 160.00 g (0.56 mol) of 2,2'-bis [4- (4-maleimidephenoxy) phenyl] propane as a bismaleimide compound and 600 g of phenol as a solvent were added to 50. The temperature was raised to ° C., the mixture was uniformly dissolved, and the reaction was carried out for another 1 hour, but the reaction did not proceed. Further, the reaction temperature was raised to 150 ° C. and the reaction was carried out for 3 hours, but Michael addition of the secondary amine and bismaleimide did not proceed, and only a part of bismaleimide self-polymerization proceeded. No maleimide resin was obtained. A GPC chart of the reaction product showing this is shown in FIG.

Table 1 summarizes the synthesis conditions, the shape of the obtained resin, the content of the n = 0 component, and the softening points for each of Examples 1 to 3 and Comparative Examples 1 to 3.

[Melting point / solubility of maleimide resin]
Resins A to C obtained in Examples 1 to 3 and 2,2'-bis [4- (4-maleimidephenoxy) phenyl] propane (compound) which is a raw material thereof and is a bismaleimide which has not undergone a Michael addition reaction. Table 2 summarizes the comparison between the melting point of A) and the solubility in methyl ethyl ketone (MEK) at 25 ° C.

[Melting point evaluation conditions]
Equipment: Differential scanning calorimetry (DSC) TA Instrument Q-2000
Heating rate; 10 ° C / min.
Atmosphere; N ₂ (50ml / min)
Measurement temperature range; -20 ° C to 150 ° C
The temperature at the peak of the endothermic peak was taken as the melting point.

[Solubility test conditions]
It was evaluated by a solubility test by the method shown below.
Solvent: Methyl ethyl ketone (hereinafter abbreviated as MEK)
Dissolution conditions: 100 g of MEK was added to a closed container, the resin was added little by little until it was no longer dissolved at room temperature (25 ° C.), and the final dissolved amount was recorded as solubility.

[Curability evaluation]
Curability was measured using the following equipment.
Equipment used: Cyber Co., Ltd. Automatic curing time measuring device Measuring conditions: 150 ° C 600 rpm
Measuring method: A maleimide resin alone or a maleimide composition containing a maleimide resin and a curing agent and a curing accelerator is prepared in a 50% by mass MEK solution. The prepared MEK solution is placed on a hot plate of an approximately 0.6 mL weighing device and measured. The time when the torque became 20% of the measurement upper limit torque value of the device was measured as the gelling time.

Regarding the resin A obtained in Example 1 and the resin D obtained in Comparative Example 2, the gelation time of the resin alone at 170 ° C. was measured and summarized in Table 3.

For the resin A obtained in Example 1 and the resin D obtained in Comparative Example 2, a maleimide composition containing a curing agent and a curing accelerator was prepared, the gelation time at 150 ° C. was measured, and summarized in Table 3. rice field.

-Curing agent: Allyl phenol resin (o-allyl phenol resin MEH-8000H manufactured by Meiwa Kasei Co., Ltd. Allyl group equivalent: 141 g / eq)
・ Maleimide resin / curing agent ratio: Equivalent number ・ Curing accelerator: Dicumyl peroxide
-Amount of curing accelerator added: 0.5 mol% to allyl group equivalent, 2.0 mol%

[Preparation of cured product using maleimide resin of the present invention and evaluation of physical properties]
The materials used in the preparation of the cured product will be described below.
(1) Allyl phenol resin
o-allyl phenol resin: "MEH-8000H" manufactured by Meiwa Kasei Co., Ltd., allyl group equivalent: 141 g / eq (2) Curing accelerator dicumyl peroxide (DCPO)
(3) Copper foil: Electrolytic copper foil (CF-T9B-THE manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., thickness 35 μm)

The cured product evaluation method will be described below. In the evaluation of (1) below, the resin compositions obtained in Example 8 and Comparative Examples 6 and 7 below were cured by the method described in (1) below. Further, in the evaluations of (2) and (3) below, the resin compositions obtained in Example 8 and Comparative Examples 6 and 7 were cured by the methods described in Example 8 and Comparative Examples 6 and 7 below.
(1) Adhesiveness (peel strength)
The maleimide resin composition was melted at 130 ° C. and impregnated with glass cloth (Arisawa Mfg. Co., Ltd. M2116) to prepare a prepreg. After stacking eight of these prepregs, both sides were sandwiched between copper foils (Fukuda Metal Foil Powder Industry Co., Ltd. CF-T9B-THE) and pressed at 130 ° C. Further, the copper-clad laminate was obtained by heating at 200 ° C. for 1.5 hours and then at 230 ° C. for 1.5 hours. The copper foil of this laminated body was etched to form a 10 mm strip-shaped pattern, which was used as a test piece. The 90 ° peel strength of the test piece was measured using an autograph (AG-5000D manufactured by Shimadzu Corporation) under the following conditions.
(Measurement condition)
Peeling speed: 50 mm / min

(2) Thermal characteristics The obtained cured product was cut into a shape of thickness 2 mm × width 5 mm × length 5 mm to obtain a test piece. The glass transition temperature of the test piece was measured using a thermomechanical analyzer (TA-600 manufactured by Shimadzu Corporation) under the following conditions. The glass transition temperature (Tg) was measured at a heating rate of 5 ° C./min.
(Measurement condition)
Temperature temperature condition: 5 ° C / min Upper limit of measurement: 350 ° C
Atmosphere: 30 mL / min nitrogen flow

(3) Mechanical properties The obtained cured product was cut into a shape of thickness 2 mm × width 25 mm × length 40 mm to obtain a test piece. The stress and elastic modulus of the test piece by the three-point bending test were measured using a universal testing machine with a constant temperature bath (manufactured by A & D Co., Ltd.) under the following conditions.
(Measurement condition)
Test speed: 2 mm / min Distance between fulcrums: 60 mm
Temperature: 25 ° C

(Example 8)
MEH-8000H 9.62 g (number of allyl groups per charge (equivalent) 0.07 mol) was heated and stirred at 130 ° C., and resin A 40.00 g (number of maleimide groups per charge (equivalent)). 0.07 mol) was added and melt-mixed with stirring. The mixture was stirred until the resin A was completely melted and the mixed bubbles disappeared. Further, 0.18 g of dicumyl peroxide as a curing accelerator was added and stirred to obtain a resin composition.
The obtained resin composition was vacuum defoamed, cast into a mold, and heat-treated at 200 ° C. for 1.5 hours and then at 230 ° C. for 1.5 hours to obtain a cured product.

(Comparative Example 6)
MEH-8000H 7.64 g (number of allyl groups per charge (equivalent) 0.05 mol) was heated and stirred at 110 ° C., and resin D 30.00 g (number of maleimide groups per charge (equivalent)). 0.05 mol) was added, and the mixture was melt-mixed with stirring. The mixture was stirred until the resin D was completely melted and the mixed bubbles disappeared. Further, 0.44 g of dicumyl peroxide as a curing accelerator was added and stirred to obtain a resin composition.
The obtained resin composition was vacuum defoamed, cast into a mold, and heat-treated at 200 ° C. for 1.5 hours and then at 230 ° C. for 1.5 hours to obtain a cured product.

(Comparative Example 7)
MEH-8000H 49.47 g (number of allyl groups per charge (equivalent) 0.35 mol) was heated and stirred at 130 ° C., and compound A 100.00 g (number of maleimide groups per charge (equivalent)). 0.35 mol) was added and melt-mixed with stirring. The mixture was stirred until Compound A was completely melted and there were no air bubbles mixed in. Further, 2.84 g of dicumyl peroxide as a curing accelerator was added and stirred to obtain a resin composition.
The obtained resin composition was vacuum defoamed, cast into a mold, and heat-treated at 200 ° C. for 1.5 hours and then at 230 ° C. for 1.5 hours to obtain a cured product.

The glass transition temperature, bending elasticity, bending strength, maximum bending point strain, and peel strength of the cured products of Examples 8 and Comparative Examples 6 and 7 were measured. The results are shown in Table 4.

As shown in Table 1, from Comparative Examples 1 and 2, the maleimide resin obtained by the Michael addition reaction of bismaleimide and diamine causes self-polymerization with a slight heat unless the secondary amine is protected, so that the treatment / use can be performed. Have difficulty. In Comparative Example 3, the diamine was first made into a secondary amine to attempt Michael addition with bismaleimide, but the Michael addition reaction did not proceed. Therefore, the maleimide resin of the present invention can be suitably obtained by protecting the secondary amine of the intermediate product obtained by Michael reaction of the bismaleimide compound and the diamine compound.

As shown in Table 2, from Examples 4 to 6, the maleimide resin of the present invention has significantly improved solvent solubility as compared with the conventional bismaleimide (Comparative Example 4), and is an organic solvent together with an epoxy resin or the like. It can be suitably used for varnish applications having a step of dissolving in. In addition, since the melting point is significantly lowered, it can be used for semiconductor encapsulation materials and the like, which are required to be dissolved at a relatively low temperature.

In Table 3, by evaluation of the curability of the maleimide resin alone, gelation occurred in Comparative Example 5 which was not protected with the secondary amine, but in Example 7 where the secondary amine was protected, the reaction proceeded by itself. Not. Therefore, thermal stability is imparted by the protection of the secondary amine.
Further, in the evaluation of curability of the composition containing the allylphenol compound and the curing accelerator, good curability is given in Example 7. The long gelation time of the composition of Comparative Example 5 means that the thermal stability of the resin D, which does not protect the secondary amine, is poor, the self-polymerization of maleimide proceeds preferentially, and the resin D does not protect the secondary amine. It is considered that the cause is that the polymerization does not proceed. Therefore, the maleimide resin of the present invention has thermal stability in which self-polymerization by itself is suppressed, and a cured product can be preferably given to the allylphenol resin.

In the evaluation of the cured product shown in Table 4, in Example 8 using the maleimide resin of the present invention, excellent toughness and adhesion strength to the copper foil are shown. By introducing a flexible unit into the maleimide resin by the Michael addition reaction, the toughness was improved, or the adhesion to the copper foil was improved as the wettability to the base material was improved. In Table 4, the toughness of the cured product of Example 8 is improved as compared with Comparative Example 6, which means that the nitrogen atom derived from the diamine in the maleimide resin structure is changed from a secondary amine to a stable tertiary amine by a protective agent. It is considered that the reason is that the reaction between the diamine-derived nitrogen atom in the resin structure and the maleimide group in the curing reaction was suppressed. Further, it was shown that the cured product of Example 8 had a constant Tg and had sufficient heat resistance.

As described above, according to the present invention, it is possible to provide a maleimide resin which has improved toughness and adhesiveness of a cured product and gives a maleimide resin composition having high heat resistance. Further, according to the present invention, a maleimide resin which is excellent in solvent solubility and can be uniformly and easily dissolved in a solvent and can be suitably used for, for example, manufacturing a laminated board or an interlayer insulating material, and a maleimide resin composition using the same. , And a cured product can be provided. Further, since the maleimide resin of the present invention has a lower melting point than the conventional bismaleimide compound, it can be easily melted at a relatively low temperature, and can be suitably used for, for example, a semiconductor encapsulating material. You can.

Claims (10)

A maleimide resin represented by the following general formula (1).

(In the formula, X represents a group of the following formula (e) , Y each independently represents a divalent group containing 1 or more and 50 or less carbon atoms, and z each independently represents an acid anhydride residue. It represents a monovalent group that is a group or a halide residue, and n independently represents an integer of 0 to 20. However, n', which is the average value of n, is a value exceeding 0.)

The maleimide resin according to claim 1, wherein the n = 0 component is 90% or less. The maleimide resin according to claim 1 or 2, wherein the melting point measured by differential scanning calorimetry is 150 ° C. or lower. The maleimide resin according to any one of claims 1 to 3, wherein the solubility per 100 g of methyl ethyl ketone at 25 ° C. is 100 g or more. A maleimide compound having two maleimide groups in one molecule represented by the following general formula (2),

(X in the formula represents the group of the following formula (e) .)

A diamine compound having two amino groups in one molecule represented by the following general formula (3) and

(Y in the formula represents a divalent group containing 1 or more and 50 or less carbon atoms.) A step of reacting to obtain a maleimide resin represented by the following general formula (4).

(X in the formula represents the group of the formula (e) , Y represents a divalent group containing 1 or more and 50 or less carbon atoms independently, and n independently represents an integer of 0 to 20. However, n', which is the average value of n, is a value exceeding 0.)
Production of a maleimide resin represented by the following general formula (1), which comprises a step of reacting the maleimide resin represented by the general formula (4) with a protective agent selected from an acid anhydride or a halide. Method.

(X, Y and n in the formula are the same as those in the general formula (4). Z independently represents a monovalent group which is an acid anhydride residue or a halide residue.) The method for producing a maleimide resin according to claim 5, wherein the diamine compound having two amino groups in one molecule represented by the general formula (3) is a linear aliphatic diamine. The method for producing a maleimide resin according to claim 5 or 6, wherein the protective agent is acetic anhydride. A maleimide resin composition containing the maleimide resin according to any one of claims 1 to 4. A cured product of the maleimide resin composition according to claim 8. Maleimide resin represented by the following general formula (1').

(In the formula, X represents a group of the following formula (e) , Y each independently represents a divalent group containing 1 or more and 50 or less carbon atoms, and z each independently represents an acid anhydride residue. It represents a monovalent group that is a group or a halide residue, and n represents an integer of 1 to 20.)

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