JP2893845B2 - Method for producing melamine resin - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a melamine resin.

(Prior art)

A molded product obtained by heating and pressing a melamine resin molding material and curing is excellent in arc resistance, tracking resistance, electric insulation, flame resistance, surface hardness, solvent resistance, and the like. However, further improvement in arc resistance is desired from the viewpoint of safety of electric products.

[Problems to be solved by the invention]

An object of the present invention is to provide a method for producing a melamine resin which gives a molded article of a melamine resin having excellent arc resistance.

[Means for solving the problem]

The present inventors have developed melamine 100 to solve the above problems.
It is an object of the present invention to provide a method for producing a melamine resin, which comprises reacting 1 to 50 parts by weight of an alicyclic epoxy silicone with parts by weight and then reacting 20 to 50 parts by weight of formaldehyde with the reaction product.

 Hereinafter, the present invention will be described in detail.

In the present invention, the alicyclic epoxy silicone refers to a silicone having an alicyclic epoxy group at a terminal.

The compounding amount of each component in the production method of the present invention needs to be set in the range of 1 to 50 parts of alicyclic epoxy silicone with respect to 100 parts by weight of melamine (hereinafter simply referred to as parts).
If the amount of the alicyclic epoxy silicone is less than 1, the modification by the alicyclic epoxy silicone is insufficient, and the effect of improving the arc resistance of the obtained melamine resin cannot be sufficiently obtained. If the amount exceeds 50, the amount of the epoxy group in the reaction system becomes too large, so that melamine is easily gelled and a melamine resin cannot be obtained.

Formaldehyde is similarly limited to 20 to 50 parts.
If the formaldehyde is less than 20 parts, the curing speed of the obtained melamine resin is slow, and the strength of the molded product is also weak and is not suitable for practical use, and if this compounding amount exceeds 50 parts, gelation is likely to occur, This is because a melamine resin cannot be obtained. For these reactions, a commonly used reaction vessel can be used as it is.

Next, the synthesis reaction of the melamine resin in the production method,
First, the reaction of melamine with cycloaliphatic epoxy silicone
The reaction is carried out at a temperature of 100100 ° C. for about 20 to 120 minutes, and then, formaldehyde, usually formalin is added to the reaction product, and the reaction is carried out at a temperature of 80 to 100 ° C. for about 20 to 120 minutes. After these series of reactions, the lower syrup of the reaction solution separated into two layers is taken out. The resin component of this syrup is melamine resin. A method for producing a melamine resin molding material from this melamine resin syrup can be carried out under known conditions described on pages 76 to 81 of Plastic Materials Course 8 "Urea Melamine Resin" published by Nikkan Kogyo Shimbun. .

Further, by removing the solvent from the syrup, it reacts with the alicyclic epoxysilicone and further reacts with formaldehyde to prepare a melamine resin as a solid melamine resin. For the solvent removal, a normal temperature vacuum dehydration method, a vacuum heat dehydration method, a spray dryer method, a WFE (thin film evaporation method), or the like can be used. When this solid melamine resin is used, the method for producing a molding material is to pulverize the solid melamine resin,
Filler, curing agent, release agent, pigment, plasticizer, etc.
A powder molding material can be obtained by mixing in a ball mill for about 2 to 20 hours. By subjecting this powder molding material to a kneading and granulating machine, a molding material on the granules can be obtained.

The molding material of any of the above production methods can form a melamine resin molded product by compression molding, transfer molding, injection molding, or the like.

For the above-mentioned filler, release agent, curing agent, pigment, plasticizer, etc., it is possible to use a known material described on pages 84 to 90 of Plastic Materials Lecture 8 “Urea Melamine Resin” Nikkan Kogyo Shimbun. it can.

Next, the present invention will be specifically described with reference to Examples and Comparative Examples.

[Examples] Example 1 1740 g of melamine (Nissan Chemical Industries), 87 g of alicyclic epoxy silicone at both ends (Toray Silicone, BX16-854), water 60
0 g and 600 g of methanol are charged into a three-necked flask equipped with a stirring blade and a reflux tube, and heated and stirred at 77 ± 2 ° C. for 1 hour. afterwards
Add 1088 g of 40% formalin and heat and stir at 85 ± 2 ° C for 45 minutes. After standing for 10 minutes after the reaction, the reaction solution separates into two layers, so transfer the lower layer syrup to a kneader, add 1000 g of sheet pulp and 7.5 g of zinc stearate with stirring, crush and mix at 70 ° C for 40 minutes . The wet impregnated product thus obtained is dried in a drier at 90 ° C. for 30 minutes and coarsely pulverized to obtain a dried product.

This dried product is first crushed for 10 hours with a ball mill,
% Phthalic anhydride master batch 9 g, zinc stearate 12 g, and stearic acid amide 1.5 g are blended and pulverized and mixed for 1 hour to obtain a powder molding material.

This powder molding material is melted, compacted, and pulverized by a continuous kneading machine heated to 100 ° C. to obtain a granular molding material.

Example 2 Melamine (Nissan Chemical Industries) 1740 g, fat monitoring epoxy silicone at both ends (Toray Silicone, XB16-854) 600 g, water 7
80 g and 780 g of methanol are charged into a three-necked flask equipped with a stirring blade and a reflux tube, and heated and stirred at 77 ± 2 ° C. for 1 hour. Thereafter, 1660 g of 40% formalin is added, and the mixture is heated and stirred at 85 ± 2 ° C. for 1 hour. After standing for 10 minutes after the reaction, the reaction solution separates into two layers. The lower layer of syrup is transferred to a kneader, and while stirring, 1330 g of sheet pulp and 10 g of zinc stearate are added, followed by crushing and mixing at 70 ° C. for 40 minutes. The wet impregnated material thus obtained is dried in a drier at 90 ° C. for 30 minutes and coarsely pulverized to obtain a dried product.

This dried product is first crushed for 10 hours with a ball mill,
% Of a phthalic anhydride master batch, 16 g of zinc stearate, and 2 g of amide stearate, and thereafter the same as in Example 1 to obtain a granular molding material.

Example 3 1740 g of melamine (Nissan Chemical Industries), 870 g of alicyclic epoxy silicone at both ends (Toray Silicone, XB16-854), water 9
100 g of methanol and 900 g of methanol are charged into a three-necked flask equipped with a stirring blade and a reflux tube, and heated and stirred at 77 ± 2 ° C. for 75 minutes. afterwards
Add 900 g of 40% formalin and heat and stir at 85 ± 2 ° C for 1 hour. After standing for 10 minutes after the reaction, the reaction solution separates into two layers, so transfer the lower layer syrup to a kneader, add 1555 g of sheet pulp and 11.5 g of zinc stearate with stirring, crush and mix at 70 ° C for 40 minutes . Thus, the obtained wet mixture is dried in a dryer at 90 ° C. for 40 minutes and coarsely pulverized to obtain a dried product.

After this drying is crushed with a ball mill for 10 hours, 10%
Then, 14 g of phthalic anhydride master batch, 18 g of zinc stearate, and 2 g of amide stearic acid are blended, and thereafter the same as in Example 1 is performed to obtain a granular molding material.

Comparative Example 1 Melamine (Nissan Chemical Industries) 2520g and 37% formalin 260
By reacting 0 g under a NaOH catalyst at a reaction temperature of 80 ° C. for a reaction time of 60 minutes, a melamine resin syrup was obtained. Using this melamine resin syrup, add 720 g of sheet pulp, 9 g of zinc stearate, and 10 g of a 10% phthalic anhydride masterbatch as a curing agent to 3000 g of the syrup,
A dried product is obtained in the same manner as in Example 1.

After 3,000 g of the dried product was first pulverized by a ball mill for 12 hours, 12 g of a master batch of 10% phthalic anhydride, 16 g of zinc stearate, and 2 g of amide stearic acid were blended. And

In accordance with JIS-K6911 using each molding material obtained above
The test piece was formed by molding at a mold temperature of 165 ° C. for 3 minutes using a 37-ton press forming machine. This test piece is based on JIS-K6911 for arc resistance, molding shrinkage,
Measure the shrinkage after molding (110 ° C, after 168 hours),
The results are shown in Table 1.

From Table 1, the molded articles of Examples 1 to 3 formed with the melamine resin molding material using the melamine resin synthesized by the production method of the present invention have a higher arc resistance than the conventional melamine resin molding material of Comparative Example 1. It was confirmed that the film had excellent properties.

In addition, it was also confirmed that the molded products of Examples 1 to 3 had a smaller molding shrinkage and a smaller shrinkage ratio after molding (after 110 ° C. and 168 hours) than the molded product of Comparative Example 1 and were excellent in dimensional stability. .

[Effect of the Invention] By using a melamine resin molding material using a melamine resin produced by the production method of the present invention, a melamine resin molded article having excellent arc resistance can be obtained.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-173,078 (JP, A) JP-A-3-139661 (JP, A) JP-A-3-139660 (JP, A) JP-A 64-64 48818 (JP, A) JP-A-51-64594 (JP, A) JP-A-3-195716 (JP, A) JP-A-58-1557813 (JP, A) JP-A-53-129293 (JP, A) JP-B-36-7397 (JP, B1) JP-B-46-41615 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08G 12/00-12/46 C08L 61/20 -61/32 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. A method for producing a melamine resin, comprising reacting 1 to 50 parts by weight of an alicyclic epoxy silicone with 100 parts by weight of melamine, and then reacting 20 to 50 parts by weight of formaldehyde with the reaction product.