JPH05163413A - Molding material - Google Patents

Abstract

PURPOSE:To obtain a molding material having balanced moldability and the toughness, heat-resistance, etc., of the molding by mixing a novolak phenolic resin with a polyamide resin in molten state or in the form of solution and using the obtained resin as a resin component. CONSTITUTION:A resin composition is produced by homogeneously mixing (A) a novolak phenolic resin preferably having a number-average molecular weight of 500-1,500 and an unreacted phenol content of <=2% with (B) a polyamide resin at an (A:B) ratio of 99:1 to 1:99, preferably 95:5 to 5:95, especially 90:10 to 10:90, solidifying the obtained mixture by cooling and crushing the solidified product. The mixing of the components is carried out either by slowly adding the component B to molten component A and mixing the components or by mixing the components A and B in the form of solution using a polar solvent and removing the solvent from the solution mixture. When the ratio of the component A in the resin composition is high, the composition is incorporated with a curing agent (e.g. hexamethylenetetramine), a cure assistant, a filler, a releasing agent, etc., to obtain a molding material. When the content of the component B is high, the resin composition may be used as a molding material as it is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding material containing as a resin component a resin obtained by melt-mixing or solution-mixing a phenol resin which is a thermosetting resin and a polyamide resin which is a thermoplastic resin. It is a thing.

[0002]

2. Description of the Related Art Phenolic resins are excellent in heat resistance, strength, electrical characteristics and the like 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, 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 problem 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 the molded product characteristics such as impact resistance or moldability, but a resin composition having the characteristics of a phenol resin and a thermoplastic resin, particularly a molded product The material has not been obtained yet. On the other hand, looking at 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]

From such a situation,
The present applicant has completed the present invention as a result of earnest studies especially for the purpose of improving defects such as poor toughness, impact resistance and moldability of the phenol resin molding material.
It was also found that modification of polyamide resin can be achieved by blending novolac type phenolic resin.

[0004]

DISCLOSURE OF THE INVENTION The gist of the present invention is a molding material containing as a resin component a resin obtained by melt-mixing or solution-mixing a novolac type phenol resin and a polyamide resin as essential components. In the present invention, novolac type phenolic resin (hereinafter referred to as novolac)
Is not particularly limited as long as it is used for a usual molding material and the like, but one having a molecular weight (number average molecular weight) of 500 to 1500 is easy to melt-mix with a polyamide resin, and is molded. It is preferable in terms of moldability when made into a material. In addition, the less unreacted phenol is, the better the characteristics of the molded product, and it is preferably 2% or less. on the other hand,
The polyamide resin (hereinafter referred to as polyamide) may be a commercially available molding material.

Novolak and polyamide are melt mixed or solution mixed to form a homogeneous melt or solution. The mixing ratio of novolac and polyamide is not particularly limited, but if the ratio of one is extremely small, the effect of addition will not substantially appear, so the ratio of novolac to polyamide is usually 99: 1 to 1:99. .. A preferred ratio is 95: 5 to 5:95, more preferably 90:10 to 1
0 to 90. When the ratio 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 properties are excellent, and the impact resistance and various problems during molding, which are the drawbacks of phenolic resins, are significantly improved. Further, when the polyamide is 60%, the heat resistance is improved while maintaining the characteristics of the polyamide such as toughness. Thus, by melt-mixing or solution-mixing the novolac and the polyamide, the respective advantages can be taken advantage of and the drawbacks complemented.

[0006] In the melt mixing, it is usual to first melt the novolak and then gradually add the polyamide to the mixture and mix it. However, if a novolac resin containing a large amount of free phenol is used, uniform mixing is easy, and mixing is carried out if necessary. The post-free phenol may be removed. When the proportion of polyamide is considerably high, a method of melting polyamide 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. It is preferred that at least one of the components be finely ground 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 novolac and polyamide 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 and pulverized or crushed to an appropriate size. Disconnect. This composition is usually hexamethylenetetramine (hereinafter,
A curing agent such as hexamine) is added, but this may be done during mixing of the resin or after crushing. 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 the composition contains a large amount of polyamide, this composition may be used as it is as a molding material, or it may be formed into a molding material with the same composition as in the case where a large amount of novolac is contained. The filler used when forming a molding material in the present invention, wood powder, pulp powder, various woven ground 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 polyamide are uniformly mixed by melt mixing or solution mixing as described above, it is considered that these resins are not only mixed but also alloyed or reacted. As a result, the features of both resins can be used as they are, and the defects can be improved.

[0009]

EXAMPLES Next, the present invention will be described with reference to Examples and Comparative Examples. [Example 1] 90 parts of novolak (number average molecular weight 800) was heated to 170 ° C and melted, and 10 parts of polyamide (number average molecular weight about 20,000) was gradually added and mixed. After the polyamide was completely dissolved, it was taken out, cooled and pulverized to obtain a resin composition. [Example 2] A resin composition was obtained in the same manner as in Example 1 except that the ratio of novolac to polyamide was 80:20. Comparative Example 1 Only the above novolak was crushed. These resin compositions or resins alone were made into molding materials with the formulations shown in Table 1. The molding material was melt-kneaded using a twin-screw extruder. The obtained molding material was injection-molded in a mold at 170 ° C. to obtain a molded product. The bending strength and impact strength of this molded product were measured. The results are shown in Table 1.

[0010]

[Table 1]

[Example 3] 10 parts of novolak and 1.5 parts of hexamine were mixed in advance, and this was mixed with polyamide 9
Using a twin-screw extruder, 0 part was extruded while being melt-kneaded at 250 ° C. and simultaneously cut into pellets to obtain a molding material. [Example 4] 20 parts of novolac and 3 parts of hexamine were mixed in advance, this was mixed with 80 parts of polyamide, and a molding material was obtained in the same manner as in Example 4 below. [Comparative Example 2] The above polyamide pellets were used as they were. The obtained molding material was injection-molded and the heat distortion temperature of the molded product was measured. The results are shown in Table 2.

[0012]

[Table 2]

From the results shown in Table 1, Examples 1 and 2 with a large amount of novolac have higher toughness and improved strength and impact resistance as compared with Comparative Example 1 containing only novolac. The other properties were equivalent or better, and the moldability was also good. From the results of Table 2, Examples 3 to 4 containing many polyamides
Has improved heat resistance as compared with Comparative Example 2 in which only polyamide is used. Other properties and moldability were equivalent or better.

[0014]

As is clear from the above examples, when the molding material of the present invention has a large amount of novolac, the toughness of the molded product is improved as compared with the phenol resin molding material, and other characteristics are also exhibited. Good and good moldability. When the amount of polyamide is large, the heat resistance is improved while the moldability is maintained and other properties are better than those of polyamide alone.

Claims (1)

[Claims] 1. A molding material containing, as a resin component, a resin obtained by melt-mixing or solution-mixing a novolac type phenol resin and a polyamide resin as essential components.