JPH0551517A - Thermosetting resin composition - Google Patents

Abstract

PURPOSE:To obtain the title compsn. excellent in heat resistance, toughness and solvent resistance by using an epoxy resin and a specific arom. polyester as the indispensable components. CONSTITUTION:The title compsn. comprises as the indispensable components an epoxy resin (e.g., ESCN-195-6 manufactured by Sumitomo Chemical Co., Ltd.) and an arom. polyester having a chemical structure having recurring units of the formula.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FRP, a molded product, a film, used in the fields of electric parts, aircraft, automobiles,
The present invention relates to a novel thermosetting resin composition that can be used as an adhesive or the like. More specifically, the present invention relates to a thermosetting resin composition containing an epoxy resin and an aromatic polyester as essential components and having excellent heat resistance, toughness, and solvent resistance.

[0002]

2. Description of the Related Art High heat resistance and excellent mechanical properties are required for resins for advanced composite materials and films used in electric parts and aircraft. Epoxy resins are often used as resins that meet these requirements, but epoxy resins having high heat resistance generally have the drawback of being brittle. Conventionally, in order to improve the brittleness of an epoxy resin, a method of adding a liquid rubber or using a long-chain amide compound as a curing agent has been adopted. However, such a method has a drawback that the heat resistance cannot be maintained such that the elastic modulus of the cured product is lowered and the glass transition temperature is lowered. In order to solve this drawback, a method of mixing a thermoplastic resin having excellent heat resistance such as polyether sulfone has been attempted in recent years. However, in the method of mixing a thermoplastic resin such as polyethersulfone, since these thermoplastic resins are generally inferior in compatibility with the epoxy resin, it is not uniform when added to the uncured epoxy resin in the form of fine powder. Only cured products can be obtained. Further, even when the uncured epoxy resin and the thermoplastic resin are uniformly dissolved by using an organic solvent or by heating, phase separation of the epoxy resin and the thermosetting resin occurs after the solvent removal or after the curing reaction of the epoxy resin. These non-uniform cured products do not improve the mechanical properties and heat resistance of the epoxy resin, but on the other hand, it is feared that various properties such as excellent solvent resistance of the epoxy resin may deteriorate.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object thereof is to provide a thermosetting resin composition excellent in toughness, heat resistance and solvent resistance.

[0004]

That is, the present invention is characterized in that an aromatic polyester having a specific structure and an epoxy resin are essential components. The aromatic polyester applied to the present invention, a repeating unit,
General formula (1)

[Chemical 2] If it has a molecular structure shown by, the molecular weight,
When it is a copolymer, the ratio and the like are not particularly limited. This compound is generally obtained from an aromatic dicarboxylic acid or a derivative thereof and a dihydric phenol such as bisphenol A or a derivative thereof, and specific examples thereof include U polymer (Unitika, Sumitomo Chemical U-100). Be done.

The epoxy resin applied to the present invention is not limited in its molecular structure, molecular weight, etc. as long as it is a compound having an average of more than two epoxy groups in its molecule, and it is saturated or unsaturated. It may be an aliphatic, cycloaliphatic, aromatic or heterocyclic compound, and may also be a compound containing a functional group such as a halogen atom, a hydroxyl group or an ether group. Examples of such epoxy resins include diglycidyl ether compounds derived from dihydric phenols such as bisphenol A, bisphenol F, bisphenol S, hydroquinone and resorcin, or halogenated bisphenols such as tetrabromobisphenol A, phenol, o. -Novolak-based epoxy resins derived from novolak resins, which are reaction products of phenols such as cresol and formaldehyde, p-aminophenol, m-aminophenol, 4,4'-diaminodiphenylmethane, p-phenylenediamine, m- Aromatic amine-based epoxy resins derived from phenylenediamine, m-xylylenediamine and the like, Di-derived from aromatic carboxylic acids such as p-oxybenzoic acid, m-oxybenzoic acid, terephthalic acid and isophthalic acid. Examples thereof include glycidyl compounds, hydantoin-based epoxy resins, alicyclic epoxy resins, rubbers thereof, and urethane-modified compounds. In the present invention, a plurality of these epoxy resins can be used at the same time. Further, the epoxy resin in the present invention can be used in combination with a compound generally used as a curing catalyst for epoxy resins, such as imidazoles, tertiary amines and boron trifluoride complex.

The reason why a thermosetting resin composition having excellent heat resistance and toughness can be obtained by using an aromatic polyester having a specific molecular structure and an epoxy resin as essential components in the present invention is as follows. Is possible.
That is, the aromatic polyester and the epoxy resin applied to the present invention have excellent compatibility, and it is possible to obtain a uniform mixture without the reaction of the epoxy resin. In addition, it is known that an epoxy compound can form a covalent bond with an ester by an addition reaction, in Organic Synthesis Journal, vol. 49, No. 3, 218 (1991) and the like. As described above, the aromatic polyester and the epoxy resin can have a strong interaction between each other or between the matrices in a mixed state without reaction or in a cured state after the reaction, and the aromatic polyester molecule and the cured epoxy It is considered that the crosslinked network of the resin forms an extremely dense dispersed state. As a result, the excellent heat resistance and solvent resistance of the epoxy resin and the toughness of the aromatic polyester can be compatible at a high level.

The compounding ratio of the aromatic polyester and the epoxy resin in the present invention can be arbitrarily adjusted according to the kind of the aromatic polyester or the epoxy resin and the required properties. In order to obtain particularly excellent heat resistance, toughness and solvent resistance, it is preferable to use the compounding ratio of the aromatic polyester and the epoxy resin in the range of 99: 1 to 1:99 (weight ratio). When the compounding ratio of the aromatic polyester and the epoxy resin is 99: 1 (weight ratio) or more, it becomes difficult to obtain a cured product having good solvent resistance. Also, the compounding ratio of aromatic polyester and epoxy resin is 1:99.
Below (weight ratio), toughness is insufficient. The method for producing the thermosetting resin composition and the method for curing the thermosetting resin composition according to the present invention are not particularly limited, and various production methods and curing methods can be selected depending on the shape and application. Hereinafter, the present invention will be described more specifically by way of examples.

[0008]

【Example】

Example 1, Comparative Examples 1 and 2 Example 1 Epoxy resin (ESCN-195-6 manufactured by Sumitomo Chemical Co., Ltd.) 10
0 parts by weight, aromatic polyester (Sumitomo Chemical U-10
0) 230 parts by weight and curing catalyst (Wako Pure Chemical Industries, Ltd.)
2-ethyl-4-methylimidazole) produced by
A uniform solution was obtained by adding to 1650 parts by weight of N-methyl-2-pyrrolidone. Then, the solution is cast on a glass plate,
It was dried at 120 ° C. and normal pressure for 10 minutes. After that, the film-shaped resin mixture was released from the glass plate, fixed with a metal frame, and then heated at 170 ° C. for 1 hour to obtain a film-shaped resin cured product. The resin cured product was subjected to a tensile test at room temperature to determine the tensile strength, elastic modulus and elongation. In addition, the dynamic viscoelasticity test was conducted from room temperature to 300 ° C at a heating rate of 5
The same test piece was repeated twice at ℃, and the glass transition temperature was determined from the temperature at which the maximum value of the loss tangent in the second measurement was shown. Further, the solvent resistance was determined from the weight retention rate before and after immersion in N-methyl-2-pyrrolidone for 4 hours.
The results are shown in Table 1.

Comparative Example 1 In place of 230 parts by weight of the aromatic polyester and 1650 parts by weight of N-methyl-2-pyrrolidone in Example 1, 230 parts by weight of polyether sulfone (Victrex 4800G manufactured by Sumitomo Chemical Co., Ltd.) and N- A tensile test was conducted using 950 parts by weight of methylpyrrolidone and a resin cured product obtained by the same method as in Example 1. Also,
A dynamic viscoelasticity test was performed by the same method as in Example 1, but the test piece was deformed by heat at the end of the first temperature rise, and the second measurement could not be performed. Furthermore, the solvent resistance was determined from the weight retention rate before and after immersion in N-methylpyrrolidone for 4 hours. The results are shown in Table 1.

[0010]

[Table 1]

As can be seen from Example 1, the resin cured product using the thermosetting resin composition of the present invention has higher tensile strength and elongation than the resin cured product of Comparative Example 1 and therefore has high toughness. It turns out that it is excellent. In addition, the resin cured product using the thermosetting resin composition of the present invention is less deformed by repeated temperature rise than the resin cured product of Comparative Example 1,
It can be seen that the glass transition temperature is high, and therefore the heat resistance is also excellent. Further, it can be seen that the solvent resistance is also good. Comparative Example 2 Epoxy resin (Sumitomo Chemical ESCN-195-6) 10
0 parts by weight and 1 part by weight of a curing catalyst (2-ethyl-4-methylimidazole manufactured by Wako Pure Chemical Industries, Ltd.) were added to N, N-
A uniform solution obtained by adding 570 parts by weight of dimethylformamide was cast on a copper foil and dried in the same manner as in Example 1. It heated at 170 degreeC for 1 hour, and removed the copper foil after that, and obtained the resin hardened | cured material. This resin cured product is extremely brittle,
It was not possible to obtain the test pieces needed to measure the properties.

[0012]

As is apparent from the above, according to the present invention, a thermosetting resin having high heat resistance and excellent toughness can be obtained while maintaining the excellent solvent resistance which is an advantage of the epoxy resin.

Claims (1)

[Claims] 1. An epoxy resin and a repeating unit represented by the general formula (1): A thermosetting resin composition comprising an aromatic polyester having a molecular structure as an essential component.