JPH07157632A - Phenol resin composition - Google Patents

Abstract

PURPOSE:To obtain a phenol resin compsn. having higher toughness, impact strength, and abrasion resistance than a novolak resin. CONSTITUTION:A novolak phenol resin and an ethylene-ethyl acrylate-maleic anhydride copolymer are melt or soln. mixed as the essential components.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a phenol resin composition having high strength, toughness, heat resistance and abrasion resistance.

[0002]

2. Description of the Related Art Phenolic resins are excellent in heat resistance, strength and electrical characteristics among thermosetting resins and are used in various applications such as molding materials and laminated materials. When used as a molding material, the properties of the molded product are generally good, but the toughness, abrasion resistance, chemical resistance, etc. may be insufficient. In addition, during molding, many parts such as sprues and runners are discarded due to the long molding cycle. There is a drawback that burrs are unavoidable. Various studies have been made to improve such drawbacks, and one of them is mixing with a thermoplastic resin or an elastomer. So far, several materials have been studied and succeeded to some extent in improving molded product characteristics such as impact resistance or moldability. However, a resin composition having characteristics of phenol resin and thermoplastic resin, particularly molding The material has not been obtained yet. On the other hand, regarding thermoplastic resin molding materials, the toughness and moldability are good, and although there are no drawbacks of thermosetting resins as described above, thermosetting resins have several points such as heat resistance of molded products. Inferior to

[0003]

The present invention has been completed as a result of extensive studies for the purpose of improving the drawbacks such as toughness, impact resistance and moldability of conventional phenol resin compositions. .

[0004]

The present invention is a phenol resin composition obtained by melt-mixing or solution-mixing a novolac type phenol resin and an ethylene-ethyl acrylate-maleic anhydride copolymer as essential components. In the present invention, the novolac type phenolic resin (hereinafter, abbreviated as novolac) may be any one as long as it is used for ordinary molding materials and the like, and is not particularly limited, but has a molecular weight (number average molecular weight) of 500 to 1500. Is an ethylene-ethyl acrylate-maleic anhydride copolymer (hereinafter abbreviated as E-EA-MA copolymer)
It is preferable in terms of easiness of melt-mixing with and the moldability when it is made into a molding material. In addition, the E-EA-MA copolymer is
It may be one that is generally commercially available for a molding material. The novolac and E-EA-MA copolymer are melt mixed or solution mixed into a homogeneous melt or solution.

The mixing ratio of the novolak and the E-EA-MA copolymer is not particularly limited, but if the ratio of one is extremely small, the effect due to the addition thereof will not substantially appear. The proportion (weight ratio) of the copolymer is 99: 1 to 1:99. A preferred ratio is 95: 5 to 5:95, more preferably 90:10 to 10:90. When the proportion of novolac is 60% or more, the characteristics of the phenol resin mainly appear, and a composition having excellent heat resistance can be obtained. The strength and electrical characteristics are excellent, and impact resistance and various molding problems, which are the drawbacks of phenolic resins, are significantly improved. Also, E-EA-
If the content of MA copolymer is 60% or more, impact resistance E
-The heat resistance is improved while maintaining the features of the EA-MA copolymer. Thus, by melt-mixing or solution-mixing the novolac and the E-EA-MA copolymer, the advantages of the respective resins are utilized and the drawbacks are complemented.

In the melt mixing, it is usual to first melt the novolak and then gradually add the E-EA-MA copolymer to the mixture, but if a novolac resin having a large amount of free phenol is used, uniform mixing is easy, If necessary, free phenol may be removed after mixing. When the proportion of the E-EA-MA copolymer is considerably large, a method of melting the E-EA-MA copolymer and adding novolak thereto may be used. In the former case, an ordinary mixing pot may be used, but in the latter case, an apparatus having a large torque such as an extrusion kneader is preferable. At least one of the components is preferably pulverized and melt-mixed. As a method other than melt mixing, a method of solution mixing using a polar solvent is also possible, and the solvent may be removed after mixing. Since the novolac and the E-EA-MA copolymer are compatible with each other at an arbitrary ratio, a homogeneous molten or solution mixture can be obtained, which is cooled and solidified or the solvent is removed by evaporation or the like to be solidified to an appropriate size. Crush or cut into pieces. This composition is usually mixed with a curing agent such as hexamethylenetetramine (hereinafter referred to as hexamine) before use, which may be mixed with the resin or after pulverization. If the amount of novolac is small, it is not necessary to add hexamine.

A case where the above resin composition is used as a molding material will be described. When the proportion of novolac in the composition is high, hexamine, and an organic or inorganic filler, a curing aid such as calcium hydroxide, a release agent, etc. are added to this composition, and the mixture is melt-kneaded by a roll or the like and then pulverized. To do. on the other hand,
When a large amount of E-EA-MA copolymer is contained in the composition, the composition as it is may be used as a molding material,
It can also be made into a molding material as a mixture similar to the case where there are many novolacs. Fillers used when forming a molding material in the present invention, wood powder, pulp powder, various woven materials, organic materials such as crushed thermosetting resin laminates and molded products, silica, alumina, glass, Powders of talc, clay, calcium carbonate, carbon and the like, and inorganic materials such as glass fiber, carbon fiber and mica.

[0008]

When the novolac and the E-EA-MA copolymer are homogeneously mixed by melt mixing or solution mixing as described above, it is considered that these resins are not only mixed but alloyed or reacted. To be In particular, E-EA-
The ester group and the acid anhydride group contained in the MA copolymer have a good affinity for the hydroxyl group contained in the novolak, so that the bond adhesion between the resins can be improved. This makes it possible to obtain a resin composition in which the characteristics of each resin are utilized as they are and the defects are improved.

[0009]

【Example】

Example 1 Novolac (number average molecular weight of about 800) 95
Part by weight was heated to 170 ° C. and melted, and 5 parts by weight of E-EA-MA copolymer (number average molecular weight of about 4000) was gradually added and mixed. After the E-EA-MA copolymer was completely dissolved, it was taken out, cooled and pulverized to obtain a resin composition. [Example 2] 90 parts by weight of novolac, E-EA-MA
A resin composition was obtained in the same manner as in Example 1 except that 10 parts by weight of the copolymer was used.

Comparative Example 1 Only the above novolak was crushed. These resin compositions or novolaks alone were made into molding materials with the formulations shown in Table 1. The molding material was manufactured by heating and kneading using two rolls, cooling and pulverizing.

[0011]

[Table 1]

With respect to the obtained molding material, a mold at 175 ° C. was used to mold a test piece by transfer molding, and the performance of the obtained molding was measured. The results are shown in Table 2. The test piece is evaluated according to JIS K 691.
Performed according to 1.

[0013]

[Table 2]

From the results shown in Table 2, the bending strength and the impact strength of Example 1 are remarkably improved as compared with Comparative Example 1. Further, it can be seen that Example 2 is improved in bending strength and impact strength as compared with Example 1, and is a molding material having very excellent mechanical properties.

[0015]

According to the present invention, novolac and EE
The resin composition including the A-MA copolymer has toughness, impact resistance, and abrasion resistance as compared with the composition containing novolac as a main component. Therefore, a molding material using this resin composition becomes a material useful for thinning a coil bobbin having a thin flange and a machine part.

Claims (1)

[Claims] 1. A phenol resin composition obtained by melt-mixing or solution-mixing a novolac type phenol resin and an ethylene-ethyl acrylate-maleic anhydride copolymer as essential components.