JPS6033122B2 - Method for producing phenolic resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new process for producing phenolic resins.

More specifically, the present invention relates to a novel method for producing phenolic resins using polyacetal resins as a formaldehyde source. Phenolic resin is a typical thermosetting resin and is low-priced, dimensionally stable, and has high strength and durability, so it is used as electrical insulation materials, molding materials, metal surface finishing agents, and adhesives. It is used in a wide range of fields.

This phenolic resin is produced by reacting phenol with formaldehyde using an acid or base as a catalyst. Up until now, the sources of formaldehyde have been formalin, which is an aqueous solution, and paraformaldehyde, which is a trimer of formaldehyde. was used.

On the other hand, polyacetal resin is a thermoplastic resin with good electrical insulation properties, mechanical strength, and positioning properties, and is used as electrical insulation materials and various molding materials. The reality is that there is no way to reuse the waste products, so they are disposed of by incineration, etc.

As a result of extensive research into the effective use of polyacetal resin, which had previously been wasted in the past, the inventors of the present invention discovered that polyacetal resin has the drawback that it erodes in the coexistence of water and acidic substances, causing stress cracks. They focused on the fact that scales have phenolic compounds, and discovered that if this phenomenon is actively encouraged to decompose, scales become a source of formaldehyde, and that this decomposition is significantly accelerated by the presence of phenolic compounds. The present invention has been made based on this.

That is, the present invention provides a method for producing a phenolic resin, which is characterized by heating a phenolic compound and a polyacetal resin in the presence of water and an acidic catalyst.

The phenolic compounds used in the method of the present invention include, in addition to phenol, alkylated phenols such as cresol and xylenol.

In addition, as the polyacetal resin, not only homopolymers but also copolymers of formaldehyde and cyclic ethers such as ethylene oxide, polyoxymethylene derivatives having ether bonds, ester bonds, or urethane bonds in the terminal groups can be used. .

These raw material components are per 10 parts by weight of phenols,
20 to 32 parts by weight of polyacetal resin, preferably 22 parts by weight
~2 parts by weight.

Next, examples of acidic catalysts used in the present invention include inorganic acids such as hydrochloric acid and sulfuric acid, organic acids such as oxalic acid, acetic acid, and para-toluenesulfonic acid, and acidic acids such as zinc acetate and magnesium borate. salt. These acidic catalysts are used in an amount of 1 to 10 parts by weight of polyacetal resin.
It is used in a proportion of 1 part by weight. The amount of water added together with the acidic catalyst is suitably selected within the range of 2 to 20 parts by weight, preferably 5 to 1 part by weight, per 10 parts by weight of the phenolic compound.

In order to suitably carry out the method of the present invention, a mixture of a phenolic compound, a polyacetal resin, water and an acidic catalyst in a predetermined ratio is heated and melted, and while stirring,
After heating under reflux during the holding period, dehydration is performed under reduced pressure.

The heating temperature at this time is usually within the range of 100 to 20,000. Substantially no polyacetal resin remains in the phenol resin thus obtained.

In this way, it is possible to obtain a high-quality phenol resin that has no difference in chemical and physical properties from conventional formalin and paraformaldehyde. Until now, it was known that decomposition of polyacetal resin in an acidic aqueous solution takes a very long time (for example, more than a year in a 5% acetic acid aqueous solution), but due to the coexistence of phenol, it takes only a few hours. It was completely unexpected that the reaction completed in a short time, and that the copolymer of polyacetal, which had been thought to have high stability against acids, decomposed and completed the reaction in a short time just like a homopolymer. there were.

The method of the present invention uses defective and used waste polyacetal resins that have been discarded without being used in any way to produce phenolic resins of exactly the same quality as those obtained using formalin or paraformaldehyde as raw materials. Therefore, it can be said that this is a very advantageous industrial method in terms of resource saving and low manufacturing cost.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 In a three-bottomed flask with five customers, 3,000 ml of phenol,
Add pellet-shaped waste polyacetal copolymer (formaldehyde content 2.18%) 7669, 150 ml of water and 30 ml of oxalic acid, heat and melt at a temperature of 102 to 11,500 ml, reflux for 4 hours with stirring, and then increase the pressure to 73 ml. 180oo in 2 hours while decompressing to Hg
It was dried until it reached the point where it was boiled and then dehydrated.

In this way, melting point (JIS-K-6910) 74℃
, Flow 7, Geltime 72 Sand Phenolic Resin 3
Got 090 evening.

Example 2 5 In the customer's three-necked flask, 3000 g of phenol was added.
715 tons of pellet-shaped waste polyacetal, 300 tons of water, and 15 tons of zinc acetate were added, and the mixture was refluxed at 102 to 10,500 degrees Celsius while stirring for 6 hours.

Next, the mixture was dehydrated for 1 hour and 3 minutes under a pressure of 73 Hg and overflowing to 1800 C, to obtain a phenol resin of 2940 kg. This phenolic resin has a melting point (J
IS-K-6910) 68 C, flow 52 side, gel time 3 present sand, ortho-para ratio (o/p) 3.5 (according to infrared absorption spectroscopy).

No particular difference in properties was observed between this product and the phenol resin of the ``ortho-type'' obtained using formalin or paraformaldehyde as a substitute for waste polyacetal.

Comparative Example Waste Polyacetal Copolymer 766 in Example 1
A phenol resin was produced in the same manner as in Example 1, except that 92% granular paraformaldehyde 833% was used instead of 83% water, and the amount of water was changed to 833%.

This product had a melting point (JIS-K-6910) of 75 oo, a flow of 6, and a gel time of 7 seconds.

To 5 parts by weight of each of the phenolic resin obtained in Example 1 and this example, 3 parts by weight of wood flour, 2 parts by weight of calcium carbonate, and 7 parts by weight of hexamethylenetetramine.
5 parts by weight of stearic acid and 2 parts by weight of stearic acid were blended, kneaded with a roll, and then molded to prepare a sample (SF50 Rib).

The physical and mechanical properties of these samples were measured according to JIS-K-6911, and the results are shown in the table below.

As is clear from this table, the phenolic resin molded products obtained by the method of the present invention have almost no difference from conventional molded products.

Claims (1)

[Scope of Claims] 1. A method for producing a phenolic resin, which comprises heating a phenolic compound, a polyacetal resin, water, and an acidic catalyst in the presence of the mixture. 2. The method according to claim 1, wherein the phenol compound is phenol. 3. The method according to claim 1, wherein the phenolic compound is an alkylated phenol. 4. The method according to claim 1, wherein the acidic catalyst is an inorganic acid or a salt thereof. 5. The method according to claim 1, wherein the acidic catalyst is an organic acid or a salt thereof.