JPH09169890A - Melamine/phenolic resin molding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a melamine/phenolic resin molding material having excellent arc and tracking resistances and a high flexibility. SOLUTION: This molding material comprises 100 pts.wt. melamine resin having a degree of methylolation of 1.0-3.0 and a number-average molecular weight of 180-400, 10-50 pts.wt. dimethylene ether type resol resin containing 20-70mol% dimethylene ether bonds and 10-40mol% methylol groups and having a number-average molecular weight of 500-1000, 20-50 pts.wt. aluminum hydroxide, and 20-50 pts.wt. powder of a laminate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melamine / phenolic resin molding material which is excellent in arc resistance and tracking resistance and has large flexibility.

[0002]

2. Description of the Related Art Melamine resin molding materials have been used for wiring appliances, electric appliances and the like due to their excellent tracking resistance, electrical insulation, coloring property and the like. Traditionally, melamine resins are mainly made of organic fillers such as pulp, cotton dust, cloth chips, etc., and inorganic fillers such as glass, calcium carbonate, clay, mica, etc. It is included for the purpose. One of them is flexible, but the melamine resin has a larger number of functional groups than other thermosetting resins, and therefore has a high crosslink density and is likely to cause resin rigidity. Therefore, thermoplastic resin molding materials and other thermosetting resin molding materials are used for molded products that require flexibility, and melamine resins do not require flexibility but are limited to molded products that require electrical characteristics. It is used.

In recent years, due to the enforcement of the PL method (Product Liability Law), a melamine resin molding material having excellent electric characteristics has been reviewed in place of a thermoplastic resin molding material having weak electric characteristics such as flame resistance and tracking resistance. However, there is an increasing demand for a melamine resin molding material that also has the characteristics of a thermoplastic resin molding material. Conventionally, studies have been made to reduce the dimensional change rate by adding a resol-type solid or liquid phenol resin mainly containing a methylol group to a melamine resin in an amount that does not impair tracking resistance and colorability. In this case, it is known that the effect of relaxing the rigidity of the resin is effective, but the effect is not sufficient. Attempts have also been made to modify the melamine resin to suppress the rigidity of the resin itself and to develop a material with excellent flexibility, but other properties have deteriorated and sufficient flexibility has not been obtained. is the current situation.

For these reasons, the melamine resin molding material is rarely used for molded articles in the field where the thermoplastic resin molding material which requires flexibility such as fitting property and snap-in is used. Therefore, at present, the melamine resin molding material is used only for applications in which coloring properties of electric parts, foods, etc. which only require tracking resistance are absolutely necessary.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a melamine phenol resin molding material which is excellent in arc resistance and tracking resistance and has large flexibility.

[0006]

The present invention is based on 100 parts by weight of a melamine resin having a methylolation degree of 1.0 to 3.0 and a number average molecular weight of 180 to 400. 10 to 50 parts by weight of a dimethylene ether type resole resin having a number average molecular weight of 500 to 1000 containing 10 to 40 mol% of a group, 20 to 50 parts by weight of aluminum hydroxide, and 20 to 50 parts by weight of laminated plate powder. It is a melamine / phenol resin molding material characterized by:

The phenolic resin used in the present invention is a resol type phenolic resin containing a dimethylene ether bond and dehydrating and condensing by heating. The flexibility of the melamine / phenolic resin molding depends on the crosslink density of the melamine / phenolic resin molding material during curing. Since the melamine resin has 6 functional groups, which is larger than the functional group number 3 of the phenol resin, the melamine resin component has a high crosslinking density during curing. The dimethylene ether type resole resin used in the present invention has a longer internuclear distance between the phenol nuclei and the phenol nuclei than the conventionally used phenol resins mainly containing methylene groups and methylol groups, and has a methylene group of 2.
Dimethylene ether group 5.0 to 5.
8A, and the rigidity of the melamine resin is alleviated by blending the dimethylene ether type resole resin having a long bond complex. The amount of the phenol resin blended is preferably 10 to 50 parts by weight with respect to 100 parts by weight of the melamine resin. If the amount is 10 parts by weight or less, no improvement in flexibility is observed and 5
If it is 0 part by weight or more, the tracking resistance is lowered.

At the same time, the laminated plate powder to be mixed with the melamine resin is obtained by pulverizing a laminated plate having a resin content of 30 to 70% by weight as a base material such as kraft paper, cotton cloth, linter paper and the like. Laminated board powder with a particle size of 0.2 mm or less,
Usually, a material obtained by crushing mill ends, scraps generated from the lamination molding and the standard length cutting step in the manufacturing process of the laminated plate, and scraps generated in the mechanical process of the laminated plate is used. These laminates are craft paper impregnated with resin varnish, cotton cloth,
It is obtained by reacting a laminated material consisting of a vegetable fiber base material such as linter paper at high temperature and high pressure, and these organic base materials impregnated with the resin in advance are more closely attached to the resin than those compounded at the time of production. Excellent in toughness, and the toughness effect of the organic base material can be brought out while maintaining mechanical properties.

Aluminum hydroxide is added to improve flexibility. As a result of examining inorganic base materials such as mica, glass fiber, clay and aluminum hydroxide, calcium carbonate and aluminum hydroxide were effective in the order of flexibility, but calcium carbonate was one of the features of melamine resin molding material. It cannot be used because it impairs one of the flame resistance. Since aluminum hydroxide has low adhesion to the resin, it is considered that flexibility can be obtained due to the sliding effect at the interface. Aluminum hydroxide is also effective in maintaining the anti-tracking property. The particle size of aluminum hydroxide is preferably 10 μm or less as the median particle size. When the thickness is 10 μm or more, the strength is largely reduced and the effect of maintaining the tracking resistance is small.

Melamine resin for producing molding materials,
Raw materials used with phenolic resin, aluminum hydroxide, laminated plate powder, other fillers, curing agents, colorants,
For example, a release agent. The melamine resin used in the present invention is
It may be modified with epoxy resin, rubber or the like. Also,
A part of the melamine resin may be replaced with a urea resin or the like. In the method for producing a molding material using the melamine-phenol resin composition, kneading may be carried out with a usual mixing roll or twin-screw extruder, or granulation may be carried out with a high-speed rotary mixer.

The molding method for obtaining a molded product using the molding material from the melamine / phenol resin composition according to the present invention is applicable to any of injection molding, transfer molding, compression molding and the like, and is not limited. .

[0012]

EXAMPLE A raw material shown in Table 1 was kneaded with a predetermined mixing ratio by a mixing roll and pulverized to produce a molding material. Bending strength, bending elastic modulus, bending deflection amount, arc resistance, and tracking resistance (IEC.Pu
b 112) was measured. The molding of the test piece was performed by transfer molding, and the molding conditions were 150 ° C. for 3 minutes.

[0013]

[Table 1] When a dimethylene ether type resole resin, aluminum hydroxide and laminated plate powder were used as in the examples, a melamine phenol resin molding material having excellent arc resistance, tracking resistance and flexibility was obtained.

[0014]

According to the present invention, it is possible to obtain a molded article which is excellent in arc resistance and tracking resistance and has large flexibility. Therefore, arc resistance that could not be conventionally manufactured,
It is suitable as an industrial melamine / phenol resin molding material because it can easily produce a molded product for use that requires excellent tracking resistance and flexibility.

Claims (1)

[Claims] 1. A dimethylene ether bond is added to 100 parts by weight of a melamine resin having a number average molecular weight of 180 to 400.
10 to 50 parts by weight of a dimethylene ether type resole resin containing 0 to 70 mol% and a methylol group of 10 to 40 mol% and a number average molecular weight of 500 to 1000, aluminum hydroxide 20 to 50 parts by weight, and laminated plate powder 20 to A melamine / phenolic resin molding material characterized by being mixed in an amount of 50 parts by weight.