JPH1095897A - Melamine/phenolic resin molding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a melamine/phenolic resin molding material which can give a molding having excellent heat resistance and tracking resistance and high flexibility. SOLUTION: This material contains 100 pts.wt. melamine resin having a number-average molecular weight of 180-400 and 5-20 pts.wt. dimethylene ether type resol resin having a number-average molecular weight of 500-1,000 and further contains 20-50 pts.wt. base material being a powder of a laminate and a flame retardant being red phosphorus. It is desirable that the dimethylene ether type resol resin contains 20-70mol% dimethylene ether bonds and 10-40mol% methylol groups. It further contains an inorganic base material comprising 10-50 pts.wt. calcium carbonate and 5-50 pts.wt. aluminum hydroxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melamine-phenol resin molding material which is excellent in flame resistance and tracking resistance and has high 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. Conventionally, melamine resins contain organic fillers such as pulp, cotton dust and cloth chips, and inorganic fillers such as glass, clay and mica for the purpose of improving mechanical properties such as molding shrinkage, impact resistance and bending strength. It is blended. However, even if these fillers are blended, the disadvantage that the melamine resin is a hard material having a higher crosslinking density than other thermosetting resins but is a brittle material has not been solved. Therefore, thermoplastic molding materials and other thermosetting resin molding materials are used for moldings that require flexibility, and melamine resins are not limited to moldings that do not require flexibility but require electrical properties. It is used.

In recent years, with the enforcement of the PL method (product liability law), a melamine resin molding material having excellent electric properties has been reviewed in place of a thermoplastic resin molding material having weak electric properties such as flame resistance and tracking resistance. However, there is an increasing demand for a melamine resin molding material having flexibility, which is one of the features of conventional thermoplastic resin molding materials. Attempts have also been made to reduce the rigidity of the resin by adding a resol-type solid or liquid phenol resin mainly containing methylol groups to the melamine resin to such an extent that tracking resistance and coloring properties are not impaired. However, the effect is not enough. Attempts to add flexibility by combining various compounding fillers (Japanese Patent Application No. 07-332388) and development of a material with excellent flexibility that suppresses the rigidity of the resin itself by modifying the melamine resin Attempts have been made, but at the present time, there has been a decrease in other characteristics, and no satisfactory product has been obtained.

[0004] For these reasons, melamine resin molding materials are rarely used in molded articles in the field where thermoplastic resin molding materials requiring flexibility such as fitting and snap-in are used. Therefore, at present, melamine resin molding materials are used only in applications where coloring properties are absolutely necessary, such as electric parts and dishes requiring only tracking resistance.

[0005]

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

[0006]

The present invention comprises 5 to 20 parts by weight of a dimethylene ether type resole resin having a number average molecular weight of 500 to 1000 per 100 parts by weight of a melamine resin having a number average molecular weight of 180 to 400, Further, a melamine-phenol resin molding material characterized by containing 20 to 50 parts by weight of a laminated board powder as a base material and red phosphorus as a flame retardant, preferably a dimethylene ether type resole resin, It contains 20 to 70 mol% of a bond and 10 to 40 mol% of a methylol group, and further contains 10 to 50 parts by weight of calcium carbonate and 5 to 5 parts of aluminum hydroxide as an inorganic base per 100 parts by weight of a melamine resin. Melamine-phenol resin molding material containing 50 parts by weight.

The melamine resin used in the present invention preferably has a number-average molecular weight of 180 to 400 and a methylolation degree of 1.0 to 3.0, and is usually used as a melamine resin molding material.

The phenolic resin used in the present invention is a dimethylene ether type resole resin having a number average molecular weight of 500 to 1000, a resol type phenolic resin containing a large amount of dimethylene ether bonds and being dehydrated and condensed by thermal decomposition. The flexibility of a melamine / phenolic resin molded product depends on the crosslink density at the time of curing of the melamine / phenolic resin molding material. The number of functional groups in the melamine resin is 6, which is higher than the number of functional groups in the phenol resin, and the melamine resin component has a high crosslinking density during curing. The dimethylene ether type resole resin used in the present invention,
The distance between phenol nuclei is longer than that of phenol resins mainly containing a methylene group or a methylol group, and dimethylene ether groups are used for 2.8 to 3.0 angstroms of methylene groups. 0-5.
The rigidity of the melamine resin is reduced by incorporating a dimethylene ether type resole resin having a long bonding complex of 8 angstrom. The compounding amount of the phenol resin is preferably 5 to 20 parts by weight based on 100 parts by weight of the melamine resin. If the amount is less than 5 parts by weight, the improvement in flexibility is not sufficiently recognized, and if it exceeds 20 parts by weight, the tracking resistance decreases.

The laminate powder mixed with the melamine resin is obtained by pulverizing a laminate having a resin content of 30 to 70% by weight based on vegetable fibers such as kraft paper, cotton cloth and linter paper. And those having a particle size of 0.2 mm or less are preferred. Normally, a material obtained by pulverizing offcuts and waste materials resulting from the laminating and cutting processes in the manufacturing process of the laminate and the shoulder generated in the mechanical process of the laminate is used. These laminates are obtained by reacting a laminated material comprising a vegetable fiber base material such as kraft paper, cotton cloth, and linter paper impregnated with a resin varnish at a high temperature and a high pressure. Organic substrates generally have better adhesion to resins than those blended during manufacture, and can bring out the toughness of the organic substrate while maintaining mechanical properties.

Although red phosphorus used for imparting flame retardancy can be used alone, it is also possible to use a master batch product or the like mixed with an inorganic filler in order to increase safety during handling. it can. The addition amount is preferably 0.2 to 3% by weight based on the whole molding material. If it is less than 0.2% by weight, the effect is small, and even if it is added more than 3% by weight, red phosphorus itself burns more easily than the non-added one, and improvement in flame resistance cannot be expected.

[0011] Aluminum hydroxide and calcium carbonate are added to improve flexibility. As a result of examining inorganic base materials such as mica, glass fiber, clay, aluminum hydroxide, and calcium carbonate, the flexibility was effective in the order of calcium carbonate and aluminum hydroxide, but use of calcium carbonate alone Is used in combination with aluminum hydroxide, because one of the features of the melamine resin molding material may be insufficient flame resistance. Since aluminum hydroxide and calcium carbonate have low adhesion to the resin, it is considered that flexibility is obtained by the sliding effect at the interface. Aluminum hydroxide is also effective in maintaining the anti-tracking property. The calcium carbonate preferably has a central particle diameter of 10 μm or less. If it exceeds 10 μm, there is a decrease in strength,
Further, the effect of maintaining tracking resistance is small.

The amount of aluminum hydroxide is preferably 5 to 50 parts by weight based on 100 parts by weight of the melamine resin. 5
If the amount is less than 5 parts by weight, the effect of the flexibility is not sufficiently recognized.
If it exceeds 0 parts by weight, stable injection molding is difficult. The amount of calcium carbonate is preferably 10 to 50 parts by weight based on 100 parts by weight of the melamine resin. If the amount is less than 10 parts by weight, the effect of flexibility is not sufficiently recognized, and if it exceeds 50 parts by weight, sufficient flame resistance cannot be obtained.

Raw materials used together with melamine resin, phenolic resin, aluminum hydroxide, calcium carbonate, and laminate powder to produce a molding material include other fillers, curing agents, coloring agents, release agents, and the like. The melamine resin used in the present invention may be modified with an epoxy resin, rubber or the like. Further, 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 article using the molding material from the melamine-phenol resin composition according to the present invention can be applied to any of injection molding, transfer molding, compression molding and the like, and is not limited. .

[0015]

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. For the obtained molding material, the flexural strength, flexural modulus, flexural deflection, flame resistance and tracking resistance (IEC. Pub.
112) was measured. The molding of the test piece was performed by transfer molding, and the molding conditions were 150 ° C. for 3 minutes.

[0016]

[Table 1] * 1: Degree of methylolation 1.70, number average molecular weight 300 * 2: 50 mol% of dimethylene ether group, 15 mol% of methylol group, number average molecular weight 750

(Measurement method) Flexural strength, flexural modulus, flexure: JIS K
According to 7203 2. Flame resistance: according to UL-94 Thermal stability during injection molding: The injection waiting time during which continuous molding was possible was measured. The cylinder temperature is 90 ° C. in the nozzle section and 40 ° C. in the hopper section.

As in the embodiment, by using a dimethylene ether type resole resin, laminated board powder and red phosphorus as the melamine resin, and further using aluminum hydroxide and calcium carbonate, excellent flame resistance and tracking resistance are obtained, and A melamine-phenol resin molding material having excellent flexibility was obtained.

[0019]

According to the present invention, it is possible to obtain a molded article excellent in flame resistance and tracking resistance and having high flexibility. Therefore, it is suitable as an industrial melamine-phenol resin molding material because it can easily produce a molded article for applications requiring flexibility, which is excellent in flame resistance, tracking resistance, and flexibility that could not be produced conventionally. .

Claims (4)

[Claims] 1. A melamine resin having a number average molecular weight of 180 to 400 and 100 parts by weight of a melamine resin have a number average molecular weight of 500 to 100.
A melamine-phenol resin molding material comprising 5 to 20 parts by weight of a dimethylene ether type resole resin of No. 0, 20 to 50 parts by weight of a laminate powder as a base material, and red phosphorus as a flame retardant. . 2. A dimethylene ether type resole resin,
2. A composition containing 20 to 70 mol% of a dimethylene ether bond and 10 to 40 mol% of a methylol group.
The melamine-phenol resin molding material according to the above. 3. The composition according to claim 1, wherein the inorganic base contains 10 to 50 parts by weight of calcium carbonate and 5 to 50 parts by weight of aluminum hydroxide based on 100 parts by weight of the melamine resin.
The melamine-phenol resin molding material according to the above. 4. The method according to claim 1, wherein red phosphorus is added in an amount of 0.2 to the whole molding material.
The melamine / phenolic resin molding material according to claim 1, which is contained in an amount of from 3 to 3% by weight.