JP3513558B2 - Thermosetting resin, method for producing the same, and cured product obtained by curing the resin - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is a thermosetting resin composed of an alicyclic hydrocarbon having a specific side chain structure, which exhibits particularly low hygroscopicity and is suitable for electronic parts and the like. Regarding resin.

The present invention also relates to a suitable method for producing the thermosetting resin and a cured product obtained by curing the thermosetting resin.

[0003]

2. Description of the Related Art Thermosetting resins are widely used in fields requiring high reliability while having disadvantages as compared with thermoplastic resins such as molding cycle. This is due to the fact that the crosslinked structure peculiar to the thermosetting resin develops high heat resistance and dimensional stability, but this crosslinked structure also has the drawback of increasing moisture absorption of the cured resin product. Therefore, in applications such as electronic parts, problems such as corrosion of metal parts and cracks during soldering are likely to occur,
In many cases, the original characteristics of the thermosetting resin are not utilized.

In order to overcome this problem, studies have been made to introduce a structure for reducing the moisture absorption rate into the skeleton of the thermosetting resin. For example, a method of introducing a water-repellent skeleton such as a fluorinated epoxy resin or a method of suppressing moisture absorption by reducing polar groups in the molecule or reducing the crosslink density is known. However, these methods are to modify the basic skeleton of the thermosetting resin, and it is unavoidable that the basic characteristics such as heat resistance are deteriorated.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a thermosetting resin having a low moisture absorption rate and high reliability as a thermosetting resin, a suitable method for producing the thermosetting resin, and a curing obtained by curing the resin. The purpose is to provide things.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to obtain a thermosetting resin having a low moisture absorption rate without deteriorating the basic characteristics of the thermosetting resin, and as a result, a specific alicyclic ring was obtained. It has been found that a novel thermosetting resin having two kinds of functional groups capable of reacting with each other on the side chain of hydrocarbon has desired properties, and based on this finding, the present invention has been completed. It was

That is, the present invention provides a thermosetting resin having an alicyclic hydrocarbon main chain represented by the following formula (1).

[0008]

[Chemical 4] (In the formula, R ¹ represents a methyl group or an ethyl group, R ² represents ^one of two kinds of side chains represented by the following formulas (2) and (3), and R ³ represents hydrogen or a hydrocarbon group. Where m is the number of groups having a 3,4-dihydro-1,3-2H-benzoxazine ring represented by formula (2), and n is the number of groups having a phenol ring represented by formula (3). Where m and n are 1 ≦ n ≦ m ≦
Within the range of 5. )

[0009]

[Chemical 5] (In the formula, R ⁴ is a methyl group, a cyclohexyl group, a phenyl group or a substituted phenyl group.) The two kinds of side chains in the thermosetting resin (1) are J. Org.
As shown in Chem., 30 3423 (1965), they react with each other by an aminoalkylation reaction and are linked by a stable aminomethylene bond. This means that the main chains of the hydrocarbons form cross-links due to new bonds, which means that they have properties as a thermosetting resin. The ratio (m / n) of these two kinds of side chains is expected to be the highest when m / n = 1 from the mechanism of the aminoalkylation reaction. In a solid state reaction such as a curing reaction, 3,4-dihydro-1,
A slightly excessive amount of the 3-2H-benzoxazine ring (hereinafter sometimes referred to as a dihydrobenzoxazine ring) improves the properties of the cured product, so m in the formula (1),
The value of n must be 1 ≦ n ≦ m ≦ 5. m,
The preferable value of n is 2 ≦ n ≦ m ≦ 5.

The thermosetting resin having two kinds of side chains as described above is a form of alicyclic hydrocarbon having a phenol ring represented by the following formula (4) as a side chain, formaldehydes and methylamine,
Prepared by reacting with any primary amine selected from cyclohexylamine, aniline and substituted aniline to convert a part of the side chain phenol ring into a 3,4-dihydro-1,3-2H-benzoxazine ring. To be done.

[0011]

[Chemical 6] (In the formula, R ¹ represents a methyl group or an ethyl group, R ³ represents a hydrogen or a hydrocarbon group, and m and n represent integers within the range of 1 ≦ n ≦ m ≦ 5.) Is formalin heated to 70 ° C. or higher, and a mixture of an alicyclic hydrocarbon having a phenol ring as a side chain and a primary amine or a mixture of this mixture and a solvent is gradually added thereto for 30 minutes to 10 hours. By reacting, a dihydrobenzoxazine ring is easily produced.

The alicyclic hydrocarbon having a phenol ring as a side chain is a commercially available compound having the structure, for example, a number average molecular weight of 1,000 to 2 as shown by the following structure.
000, OH equivalent is 300-600, made by Nippon Petrochemical p
p-700-300 and the like are preferably used.

[0013]

[Chemical 7] (In the formula, m + n is 2 to 4, R ¹ is a methyl group or an ethyl group,
R ³ is hydrogen or a hydrocarbon group. ) Such a method for crosslinking a compound having a phenolic hydroxyl group exists in addition to forming a dihydrobenzoxazine ring, but it has drawbacks such as generation of a volatile by-product, and a preferable method is I can't say.

As the primary amine, methylamine,
Examples thereof include cyclohexylamine and aniline.

The thermosetting resin of the present invention has a temperature of 160 ° C. or higher,
Preferably at a temperature of 180 ° C to 200 ° C for 30 minutes to 2
The aminoalkylation reaction can be sufficiently completed by heating for a time. Therefore, in order to cure the thermosetting resin of the present invention, the resin is filled in the mold,
It is suitable to perform heat molding under the above conditions.

The cured product obtained by curing the thermosetting resin of the present invention has a low hygroscopicity and is also excellent in basic properties such as heat resistance as a thermosetting resin.

[0017]

The thermosetting resin of the present invention is imparted with thermosetting property by appropriately partially cross-linking the alicyclic hydrocarbon main chain, so that reliability comparable to general thermosetting resins can be obtained. The low hygroscopicity due to the alicyclic hydrocarbon main chain is maintained, and as a result, a low hygroscopic thermosetting resin having an excellent property balance as an electronic material can be obtained.

[0018]

EXAMPLES The present invention will be specifically described below with reference to specific examples, but the present invention is not limited thereto.

Example 1 Nippon Petrochemical's special phenol resin, trade name pp-70
15-8.5 g (corresponding to 0.5 mol of OH group) of 0-300 (OH equivalent 317), 31.0 g (0.33 mol) of aniline and 35 g of methyl ethyl ketone were mixed to prepare a uniform mixed solution. Formalin (37% aqueous solution) 54.1 g
(0.67 mol) was heated to 80 ° C. in a 500 cc flask, the above mixed solution was gradually added thereto in 15 minutes, and the mixture was stirred as it was for 90 minutes at a reflux temperature. Then, this reaction product was taken out, dried under reduced pressure at 80 ° C. for 8 hours, and pulverized to obtain an alicyclic hydrocarbon having a dihydrobenzoxazine ring and a phenol ring in its side chain. The infrared spectrum of this resin is shown in FIG. Formation of the dihydrobenzoxazine ring was confirmed by absorption at 900-1000 cm ^{-1 in} the spectrum.

This resin was filled in a mold of 100 × 100 × 4 mm, and was hydraulically pressed at 200 ° C. for 30 minutes-30.
It was heated and pressed under the condition of kgf / cm ² to obtain a plate-shaped molded product. This was appropriately cut and subjected to a characteristic test. Table 1 shows the characteristics of the cured product.

Comparative Example 1 In the same manner as in Example 1, 114.2 g of bisphenol A (corresponding to 0.5 mol of OH group) was used in place of pp-700-300, and a similar reaction was carried out to form a dihydrobenzoxazine ring and a phenol ring in the molecule. To obtain the compound. Also,
A cured product was produced under the same conditions as in the example. Table 1 shows the characteristics of the cured product.

Comparative Example 2 pp-700-300 158.5 g, formalin 12
2 g and 0.1 g of sodium hydroxide were weighed out in a 500 cc flask, reacted at 50 ° C. for 12 hours, the supernatant was removed, and then dried under reduced pressure at 40 ° C. for 12 hours, and the phenol ring was methylolated pp-700- I got 300. This was heated and pressed in the same manner as in the example, but a large amount of gas was generated and a uniform cured product could not be obtained.

[0023]

[Table 1] The bending strength and the bending elastic modulus were measured by a three-point bending test (bending speed 2 mm / min) with a fulcrum distance of 64 mm. The glass transition temperature was measured at 5 ° C./min in a compression mode of a thermomechanical property measuring device (TMA), and was determined from the inflection point of expansion coefficient. The moisture absorption rate was determined by increasing the weight 20 hours after the pressure cooker test.

[0024]

According to the present invention, a thermosetting resin having a small hygroscopicity and a high reliability as a thermosetting resin was obtained.

[Brief description of drawings]

FIG. 1 is an IR spectrum of the thermosetting resin obtained in Example 1.

Continuation of the front page (56) Reference JP-A-7-188364 (JP, A) JP-A-6-107909 (JP, A) JP-A-10-168283 (JP, A) JP-B-63-46088 (JP , B2) (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08G 10/00-14/14 C08G 61/00-61/12

Claims (3)

(57) [Claims] 1. A thermosetting resin having an alicyclic hydrocarbon main chain represented by the following formula (1). [Chemical 1] (In the formula, R ¹ represents a methyl group or an ethyl group, R ² represents ^one of two kinds of side chains represented by the following formulas (2) and (3), and R ³ represents hydrogen or a hydrocarbon group. Where m is the number of groups having a 3,4-dihydro-1,3-2H-benzoxazine ring represented by formula (2), and n is the number of groups having a phenol ring represented by formula (3). Where m and n are 1 ≦ n ≦ m ≦ 5
Is within the range of. ) [Chemical 2] (In the formula, R ⁴ is a methyl group, a cyclohexyl group, a phenyl group or a substituted phenyl group.) 2. An alicyclic hydrocarbon having a phenol ring represented by the following formula (4) as a side chain is reacted with formaldehyde and any primary amine selected from methylamine, cyclohexylamine, aniline and substituted aniline. And a method for producing a thermosetting resin. [Chemical 3] (In the formula, R ¹ represents a methyl group or an ethyl group, R ³ represents a hydrogen or a hydrocarbon group, and m and n represent integers within the range of 1 ≦ n ≦ m ≦ 5.) 3. A cured product obtained by curing the thermosetting resin according to claim 1.