JPH05186530A - Thermosetting resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which has a relatively low melting point and can give a cured product excellent in heat resistance, mechanical strengths, chemical stability, etc., under mild conditions by mixing a specified aromatic polyazomethine oligomer with a maleimide derivative. CONSTITUTION:100 pts.wt. aromatic polyazomethine oligomer of formula I or II [wherein R1 is a bivalent aromatic residue, R2 is a bivalent aromatic residue derived from an at least trifunctional aromatic polyamine; A and B are each an aliphatic or aromatic polymerizable unsaturated group (A may be the same as B); D is a residue derived from an aliphatic or aromatic polymerizable unsaturated aldehyde bonded to the aromatic polyamine through an azomethine bond or from an unsaturated aldehyde synthesized from an unsaturated amine and a dialdehyde (A and/or B may be the same); and n is 0-15] is mixed with 1-200 pts.wt. maleimide derivative to obtain a thermosetting resin composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant synthetic resin, and more particularly to a heat-curable resin composition of heat-resistant aromatic polyazomethine which is excellent in processability at low temperature and imparts thermosetting property.

[0002]

2. Description of the Related Art As the demand for the plastics industry has increased, industrial materials having special properties have been required, and this tendency has been rapidly increasing in combination with the sophistication of technology.

The demand for improved heat resistance is also strongly demanded for plastic materials, and the market is expanded as an industrial material in the fields where heat resistance is required, such as heat resistant films, fibers, laminates, laminates and adhesives. It also aims to expand into a wide range of new fields with new features and new functions.

In response to such demands, a group of synthetic resins called engineering plastics such as aromatic polyamide, polyimide, polysulfone, polyphenylene oxide, etc. have already been developed and have new functions different from conventional synthetic resins. Industrially produced as plastic, it is opening up new demand fields.

Among these polymer materials, a polymer having a --CH.dbd.N-- bond in the main chain repeating unit (polyazomethine) is
Due to its excellent heat resistance, flame retardancy, electroconductivity, photochromism, etc., a large amount of polymer was obtained due to the poor solubility of this polymer, despite the fact that many studies were conducted from early on. Therefore, it could not be a molded product.

On the other hand, terephthalaldehyde and 3,
When 4-diaminodiphenyl ether and a p-phenylenediamine derivative are used as main raw materials and these are reacted at a predetermined mixing ratio, a predetermined amount of diamine component is added, for example, N-methylpyrrolidone (NMP), hexamethylphosphortriamide ( There has been proposed a method of obtaining a polycondensate (polymer) by dissolving it in HMPA), adding dialdehyde, which is one raw material, as a solution, and reacting the solution.

In this case, a metal halide such as lithium chloride or calcium chloride is added for solubilization (JP-A-63-234030).

However, since impurities such as metal ions remain in the molded product thus obtained, which adversely affects the electrical characteristics in particular, there is a drawback that its use is extremely limited.

That is, this thermosetting resin is generally used in many cases, especially in insulating materials for electric and electronic devices, printed wiring boards, laminated boards, etc., but its electrical characteristics deteriorate due to the presence of lithium ions, calcium ions and chlorine ions. Or
However, there are problems such as corrosion of electrodes of electric / electronic devices and printed wiring boards. Therefore, in reality, polyazomethine cannot be put to practical use even though it has excellent heat resistance.

On the other hand, it is also well known that, apart from this, one of the typical heat-resistant resins is a dimaleimide and an aromatic diamine which are polymerized by the addition reaction of an amino group to an unsaturated bond by the Michael reaction. (“Cerimide”, Rhone Poulin, France).

However, when an attempt is made to homopolymerize maleimides, the polymerization reaction becomes too vigorous at high temperatures, and it has been difficult to obtain useful polymers.

[0012]

The present invention has excellent heat resistance of conventional polyazomethines, excellent mechanical strength at high temperatures, chemical stability, and solubility in solvents. It is an object of the present invention to provide a thermosetting resin composition of polyazomethine which can be molded at a lower temperature than that in the case and has significantly improved heat resistance.

[0013]

Means for Solving the Problems The present inventors have a relatively low melting point when molding as a molding material or a laminated plate, and can be molded into a desired shape under heating and pressurization. In order to obtain an aromatic polyazomethine having sufficient heat resistance, mechanical strength, and chemical stability after curing, it is possible to obtain the poly (meth) acrylate obtained by the condensation reaction of an aromatic polyamine and an unsaturated aldehyde. A divalent amine having a saturated bond, an aromatic dialdehyde and an unsaturated aldehyde or an unsaturated amine are reacted in the presence of a solvent to give a compound of the general formula

[Chemical 2] An aromatic polyazomethine oligomer represented by It was found that this oligomer can be cured in the presence of a radical generating catalyst, and the cured aromatic polyazomethine has the above-mentioned excellent properties.However, by further using a maleimide derivative in addition to this oligomer, The melting point of the mixture before curing can be lowered by improving the curing speed and by selecting the mixing ratio of the both.
Moreover, it was found that a molded product having sufficient heat resistance, mechanical strength and chemical stability after curing was obtained, and it was possible to complete the present invention by knowing that such a desired improvement can be made.

The aromatic polyazomethine oligomer having an unsaturated group of the present invention can be synthesized by the following reaction formula as an example.

Step 1: Synthesis of aromatic diamine from polyvalent aromatic polyamine

[Chemical 3]

Second step: Synthesis of aromatic polyazomethine oligomer containing unsaturated group

[Chemical 4]

A means for taking out the produced water out of the reaction system in order to smoothly proceed the above reaction is required, and for example, an organic solvent azeotropic with water may be added. In this case, as the azeotropic organic solvent, it is generally convenient to use a solvent such as benzene or toluene which is azeotropic with water but does not mix.

In this case, it is advantageous that the degree of polymerization n of the oligomer is 0 to 15, preferably about 3 to 7, because the moldability is easy, and polymerization at this stage is not necessary at all. This reaction is generally dissolved and heated in a mixture of amines, an inert organic solvent that dissolves the dialdehyde, and an azeotropic solvent with water. It can be carried out by removing the water produced at this time by azeotropic distillation.

2 having an unsaturated bond which can be used in the present invention
Examples of the valent amine include those synthesized by the condensation reaction of the following aromatic polyamine and unsaturated aldehyde. The aromatic polyamine which is one of the components used when synthesizing a divalent amine having an unsaturated bond by a condensation reaction of an aromatic polyamine and an unsaturated aldehyde has the following formula:

[Chemical 5] Or

[Chemical 6] Preferably

[Chemical 7] Or

[Chemical 8]

[Chemical 9] An aromatic polyamine represented by

As a precursor of an organic residue having a polymerizable unsaturated group at the terminal or inside of the terminal chain or side chain, acrolein, crotonaldehyde, vinylacetaldehyde, α-methylacrolein, α-ethylacrolein, α-methyl Unsaturated aldehydes such as crotonaldehyde, cyclohexene aldehyde, cinnamaldehyde,
A reaction mixture obtained by reacting an unsaturated amine and a dialdehyde in equimolar amounts, for example, a compound of the following formula and the like can be mentioned.

[Chemical 10]

A part of the product in this reaction includes a compound obtained by reacting both aldehyde groups with an unsaturated amine, but this is not a problem.

The unsaturated amine used in the reaction represented by the formula [B] is allylamine, methallylamine, 1
-Amino-4-pentene, m-isopropenylaniline, p-isopropenylaniline, o-aminostyrene, m-aminostyrene, p-aminostyrene and the like.

Typical examples of the aromatic dialdehyde that can be used in the present invention include phthalaldehyde, isophthalaldehyde, terephthalaldehyde and mixtures thereof.

Aromatic polyazomethines derived from phthalaldehyde are slightly insufficient in heat resistance, and when terephthalaldehyde is used, the heat resistance of the polymer after thermosetting is sufficient but it is obtained as a precursor. The aromatic polyazomethine oligomer has a high melting point and tends to be difficult to handle, and in terms of practicality, isophthalaldehyde has the best balanced property, which is consistent with the object of the present invention.

Since this synthetic reaction proceeds in a relatively stoichiometric manner, a desired value is put into n in the above formula [A] and calculation is carried out. Aldehydes, aromatic diamines having unsaturated bonds derived from polyvalent aromatic polyamines and aromatic dialdehydes may be reacted, and if precise adjustment is required, the molar ratio is determined by a simple test. it can.

As described above, the composition of the aromatic polyazomethine oligomer obtained by this reaction can be easily selected, and it can be easily molded at a temperature of 200 ° C. or lower.

The aromatic polyazomethine oligomer having an unsaturated group synthesized according to the present invention can be cured by the combined use of a radical generating catalyst, and the heat resistance can be remarkably improved.

The maleimide derivative used together with the aromatic polyazomethine oligomer is classified into the following three types. (I) Phenylmaleimides (ii) Dimaleimides synthesized from aromatic diamine and maleic anhydride The types of aromatic diamines mentioned above are used. (iii) Polymaleimides synthesized from polyamines such as aniline-formaldehyde condensate and maleic anhydride Further, it is possible to use a mixture of (i), (ii) and (iii).

Phenylmaleimides have a low melting point and a wide compatibility with aromatic polyazomethine oligomers,
There is a point that the heat resistance is slightly lacking, and dimaleimides made from an aromatic diamine as a raw material are generally used.

Examples of these are N-phenylmaleimide, N- (O-chlorophenyl) maleimide, N,
N'-diphenylmethane bismaleimide, N, N'-diphenyl ether bismaleimide, N, N'-paraphenylene bismaleimide, N, N '-(2-methylmetaphenylene) bismaleimide, N, N'-metaphenylene bismaleimide , N, N '-(3,3'-dimethyldiphenylmethane) bismaleimide, N, N'-(3,3 '
-Diphenyl sulfone) bismaleimide or a maleimide compound of an aniline-formaldehyde condensate.

The aromatic polyazomethine oligomer having a polymerizable unsaturated group of the present invention generally has a slow curing rate,
Even if a radical generator is used as a catalyst,
Although heating to a high temperature is required, the curing rate can be improved by blending the maleimide derivative.

Further, it has the effect of improving the moldability (decreasing the melting point) of the composition containing the maleimide derivative before curing, and can be processed at low pressure.

The mixing ratio of the aromatic polyazomethine oligomer and the maleimide derivative is 1 to 200 parts by weight, preferably 5 to 100 parts by weight, based on 100 parts by weight of the aromatic polyazomethine oligomer.

When the amount of the maleimide derivative added is less than 1 part by weight, the heat resistance is good, but the drop in the melting point is small and the effect of improving the moldability is small. Further, even if the amount is more than 200 parts by weight, the melting point shows a substantially constant value, and further lowering of the melting point is not observed, and the heat resistance of the molded product is lowered, and at the same time, the polymerization reaction becomes violent, which makes control difficult. There is a problem of becoming. The mixture of the aromatic polyazomethine oligomer and the maleimide derivative according to the present invention can be cured by the combined use of a radical generating catalyst, and the heat resistance can be markedly improved.

Although the radical generating catalyst is not limited,
Industrially, the peroxide type is suitable, and when the molding temperature is 100 ° C. or higher, the so-called high temperature decomposition type,
For example, dicumyl peroxide type is used.

The amount used is 5 phr or less, preferably 0.5
~ 3 phr is suitable. Further, the combined use of the monomer capable of copolymerizing with the unsaturated bond of the aromatic polyazomethine oligomer of the present invention is possible when the monomer dissolves the aromatic polyazomethine oligomer and the maleimide derivative, and particularly when the polymerization degree n of the oligomer is When the value is small, the applicable range is wide.

In the production of a molded article using the aromatic polyazomethine oligomer having an unsaturated group according to the present invention, a reinforcing agent, a filler, a release agent, a colorant, another polymer as a low-shrinking agent, etc. are required. Of course, they can be used in combination.

The composition thus blended has a high stability at room temperature, and it is needless to say that it is blended just before use, but it can be stored and transported in a form containing a radical generating catalyst for a short period of time. is there.

[0039]

The present invention synthesizes a polyazomethine oligomer having a radical-polymerizable unsaturated group introduced into its terminal chain to give it solubility in an organic solvent and facilitate molding at low temperatures, while at the same time providing the heat resistance characteristic of a thermosetting resin. , When the polymer having mechanical strength is blended with a maleimide derivative, the molding temperature is lowered and the curing speed is improved.
It enables molding under low pressure. Next, in order to help understanding of the present invention, examples will be shown below.

[0040]

【Example】

(Synthesis Example 1) Synthesis of polyazomethine oligomer [I] In a 500 ml four-neck separable flask equipped with a distillation apparatus, a thermometer, and a stirrer, 6.7 g of isophthalaldehyde was added.
(0.05 mol) and 100 g of DMF are charged and dissolved. Next, 2.85 g (0.05 mol) of allylamine was dissolved in 50 g of benzene, added to the reaction flask, and stirred at room temperature for 3 hours.
Stir for 0 minutes to synthesize unsaturated aldehyde. next,

[Chemical 11] 24.15 g of trivalent aromatic amine represented by (0.05
Mol) was dissolved in 50 g of DMF and 50 g of benzene, added to a reaction flask, and stirred at room temperature for 30 minutes to synthesize a diamine having an unsaturated group. To the above reaction solution, 8.04 g (0.06 mol) of isophthalaldehyde was added, and after stirring at room temperature for 30 minutes, 1.14 g (0.02 mol) of allylamine was dissolved in 50 g of benzene and charged into a reaction flask for 30 minutes. Stir at room temperature. The temperature of this mixture is raised, and after reacting at 80 ° C. for 1 hour, the temperature is further raised to distill off benzene. After the distillation of benzene and condensed water is completed, the reaction product is gradually added to about 1.5 liters of water which is vigorously stirred to precipitate crystals. The precipitated crystals were suction filtered, washed with water and dried to obtain polyazomethine oligomer [I].

(Synthesis example 2) Synthesis of polyazomethine oligomer [II] In a 500 ml four-neck separable flask equipped with a distillation apparatus, a thermometer and a stirrer.

[Chemical 12] 28.98 g (0.06 mol) of a trivalent amine represented by and DMF 100 g are charged and dissolved. To this solution, 4.2 g (0.06 mol) of crotonaldehyde and 50 g of benzene are charged and stirred at room temperature for 30 minutes to synthesize an unsaturated diamine bound with an azomethine group. Next, 6.7 g (0.05 mol) of isophthalaldehyde and 100 g of benzene were charged and dissolved in the above reaction mixture. After dissolution, the temperature is raised and the reaction is carried out at 80 ° C. for 1 hour, and then the temperature is further raised to distill off benzene and the produced condensed water. After the distillation of benzene and condensed water is completed, the reaction product is gradually added to about 1.5 liters of water which is vigorously stirred to precipitate crystals. The precipitated crystals were suction filtered, washed with water and dried to obtain polyazomethine oligomer [II].

(Synthesis Example 3) Polyazomethine oligomer [I
II] Synthesis Acrolein (95%) instead of crotonaldehyde
The same operation as in Synthesis Example 2 was performed except that 3.54 g (0.06 mol) was used to obtain a polyazomethine oligomer [III].

(Synthesis Example 4) Synthesis of polyazomethine oligomer [IV] The same operation as in Synthesis Example 2 was conducted except that 7.92 g (0.06 mol) of cinnamic aldehyde was used instead of crotonaldehyde, and the polyazomethine oligomer was synthesized. Obtained [IV].

Example 1 1 part by weight of the polyazomethine oligomer [I] obtained in Synthesis Example 1, 0.1 part by weight of N-phenylmaleimide, and 1.1 parts by weight of dicumyl peroxide (2% acetone solution) were added. Add to test tube and mix evenly.
Next, the temperature was gradually raised and heated at 80 ° C. for 1 hour to remove acetone and dry. After drying, the temperature was raised to 160 ° C. to cure for 1 hour. When the temperature was further raised to 200 ° C. and curing was carried out for 5 hours, a solid, insoluble and infusible bulk polymer having an amber color was obtained. The obtained polymer was crushed in a mortar and dried in the air for 10
When thermogravimetric analysis was performed at a temperature rising rate of ° C / min, the result was (1) in Fig. 1. 95% weight retention rate temperature 396 ° C. 90% weight retention rate temperature 453 ° C. weight retention rate at 500 ° C. 83.7%

Example 2 Except that 1 part by weight of the polyazomethine oligomer [I] synthesized in Synthesis Example 1, 1 part by weight of N-phenylmaleimide, and 2 parts by weight of dicumyl peroxide (2% acetone solution) were used. The same operation as in Example 1 was performed. The obtained polymer was crushed in a mortar and dried in the air for 10
When thermogravimetric analysis was performed at a temperature rising rate of ° C / min, the result was (2) in Fig. 1. 95% weight retention rate temperature 342 ° C 90% weight retention rate temperature 381 ° C weight retention rate at 500 ° C 73.9%

Example 3 1 part by weight of oligomer [I],
1 part by weight of N, N'-diphenylmethane bismaleimide,
The same operation as in Example 1 was performed except that 2 parts by weight of dicumyl peroxide (2% acetone solution) was used. The obtained polymer was pulverized in a mortar and subjected to thermogravimetric analysis in air at a temperature rising rate of 10 ° C./min. 95% weight retention temperature 417 ° C 90% weight retention temperature 462 ° C weight retention at 500 ° C 85.4%

Example 4 1 part by weight of oligomer [II],
1 part by weight of N, N'-diphenylmethane bismaleimide,
The same operation as in Example 1 was performed except that 2 parts by weight of dicumyl peroxide (2% acetone solution) was used. The obtained polymer was crushed in a mortar and subjected to thermogravimetric analysis in air at a temperature rising rate of 10 ° C./min, and the result was as shown in (1) of FIG. 95% weight retention temperature 468 ° C 90% weight retention temperature 500 ° C or higher weight retention at 500 ° C 90.6%

(Example 5) 1 part by weight of oligomer [III],
1 part by weight of N, N'-diphenylmethane bismaleimide,
The same operation as in Example 1 was performed except that 2 parts by weight of dicumyl peroxide (2% acetone solution) was used. The obtained polymer was pulverized in a mortar and subjected to thermogravimetric analysis in air at a temperature rising rate of 10 ° C./min, and the result was as shown in (2) of FIG. 95% weight retention rate temperature 423 ° C 90% weight retention rate temperature 459 ° C weight retention rate at 500 ° C 84.5%

Example 6 1 part by weight of oligomer [IV],
1 part by weight of N, N'-diphenylmethane bismaleimide,
The same operation as in Example 1 was performed except that 2 parts by weight of dicumyl peroxide (2% acetone solution) was used. The obtained polymer was crushed in a mortar and subjected to thermogravimetric analysis in air at a temperature rising rate of 10 ° C./min, and the result was as shown in (3) of FIG. 95% weight retention rate temperature 441 ° C 90% weight retention rate temperature 483 ° C weight retention rate at 500 ° C 87.5%

(Example 7) 45 parts by weight of the oligomer [I] synthesized in Synthesis Example 1, 45 parts by weight of N, N'-diphenylmethane bismaleimide and dicumyl peroxide 1.
A glass cloth was immersed in a solution prepared by dissolving 8 parts by weight of dimethylformamide in 110 parts by weight, and then dried at 80 ° C. for 1 hour to prepare a prepreg. After that, several prepregs were superposed on each other, and the pressure was 20 Kg / cm ² and the temperature was 160.
After heat-press molding at 1 ° C. for 1 hour, post-curing was performed at 200 ° C. for 5 hours to obtain a laminated plate. The bending strength of this laminate is 25
It was 56 Kg / mm ² at ° C. Also, 200 ℃
Flexural strength after heating for 960 hours at 54 ° C at 25 ° C
/ Mm ² .

Reference Example 1 A composition obtained by adding a maleimide derivative to an aromatic polyazomethine oligomer has a remarkably lowered melting point and is easily processed. As this example, Table 1 shows melting points of N-phenylmaleimide and the oligomer [I] obtained in Synthesis Example 1 at various mixing ratios.

[0052]

[Table 1]

[0053]

INDUSTRIAL APPLICABILITY The present invention is a thermosetting polyazomethine polymer having excellent heat resistance which does not deteriorate the mechanical properties even at high temperatures without losing the excellent properties of aromatic polyazomethines, and particularly maleimide derivatives. It was possible to provide a curable resin composition having improved curability and processability by blending

[Brief description of drawings]

FIG. 1 shows the results of thermogravimetric analysis of the polymers of the thermosetting resin compositions obtained in Examples 1 to 3.

FIG. 2 shows the results of thermogravimetric analysis of the polymers of the thermosetting resin compositions obtained in Examples 4 to 6.

Claims (2)

[Claims] 1. (a) General formula: A thermosetting resin composition obtained by blending 1 to 200 parts by weight of (b) maleimide derivative with 100 parts by weight of the aromatic polyazomethine oligomer represented by. 2. The thermosetting resin composition according to claim 1, wherein the maleimide derivative is at least one of phenylmaleimide, aromatic dimaleimide and aromatic polymaleimide.