JPS5948049B2 - Method for producing fast-curing phenolic resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The purpose of the present invention is to produce a fast-curing phenolic resin safely, easily, with high yield, and at low cost. The purpose of the reaction is to use a catalyst effective for the condensation reaction in combination with a catalyst effective for the condensation reaction.

Since H-L-Bender et al. reported that a high-ortho novolak with a high ortho-bonded metal content has fast curing properties, various production methods for this high-ortho-novolak have been developed and put into practical use.

These conventional manufacturing methods include those that use one weakly acidic divalent metal as a catalyst, and those that use a weakly acidic divalent metal and an acid catalyst. Ortho-novolak is usually produced by first generating a phenol methylol compound using a weak acidic catalyst or a basic catalyst, and then condensing this.

When the reaction is carried out using only one type of weakly acidic catalyst, it is difficult to proceed with methylolation and methylenation in a well-balanced manner. When a catalyst excellent in methylation is used, gelation may occur during condensation. Further, if a catalyst with suppressed methylolation is used for safety reasons, there is an unavoidable problem that the yield and the ortho-para bond ratio, that is, the rapid curing property decreases. Therefore, methods have been considered in which methylolation is carried out using a weakly acidic or basic catalyst, and then methylenation is carried out by adding an acidic catalyst. However, these methods have problems such as heat generation control during acid injection and exothermic reaction control of rapid methylenation using an acid catalyst. For this reason, a production method has been considered in which the reflux reaction is carried out twice before and after addition of the acid catalyst. Such two reflux reactions not only lead to increased costs due to longer reaction times, but also, according to experiments conducted by the present inventors, the high ortho properties of the resin decrease during the reflux reaction, resulting in faster curing. It turned out to be lost. Furthermore, an industrially suitable manufacturing method for fast-curing high-ortho-novolaks has not been established due to the complexity of adding a catalyst twice and separately during the same manufacturing process. The present invention has solved all of the above-mentioned problems, and the purpose of this invention is to use two types of divalent metal salts with different functions, that is, to have an excellent effect on addition reaction (methylolation). 2 with
By using a valent metal salt and a divalent metal salt that has an excellent effect on the condensation reaction (methyleneation), both the addition and condensation reactions can proceed in a well-balanced manner, and a fast-curing novolak can be produced safely and at low cost. This is what we discovered.
The gist of the present invention is that the molar ratio (hereinafter referred to as F/P) of phenols and formaldehyde is 0.6 to
0.95 from divalent metal salts, and a catalyst A effective for addition reactions and a catalyst B effective for condensation reactions are used in combination from the start of the reaction. A method for producing a curable phenolic resin, in which the catalyst A used is
is selected from manganese acetate, zinc acetate, barium acetate, etc., and catalyst B is selected from zinc oxide, zinc nitrate, zinc chloride, etc. In addition, the combined ratio of both catalysts is set at a molar ratio of catalyst A/catalyst B of 0.02 to 4, and the total usage amount of the two types of catalysts is set to 0.1 to 3 wt% based on the charged phenol. It has particularly excellent effects. When carrying out the production method of this invention, it is possible to carry out the reflux reaction and then form a resin by dehydration condensation under normal pressure or reduced pressure. A method of making it into resin may also be used.

When paraform is used as the formaldehyde source used in the present invention, it has the advantage that the reaction time can be shortened and the yield relative to the total amount charged can be increased. In addition, by changing the ratio of catalysts used in combination, the ortho-para ratio (hereinafter referred to as α↑ ratio) can be determined.

) We were able to obtain the desired resin in the range of 1.0 to 3.0. [Q/P ratio was determined by nuclear magnetic resonance spectrum, Q/P ratio = {2,2'-methylene proton + 1/2 (2,4-methylene proton)}/{4,4
'-Methylene proton 11/2 (2,4-methylene proton)}] Also, the molecular weight of the resin used in the present invention is 600 to 11 in number average molecular weight excluding free phenols.
00, particularly preferably 700 to 900. The molecular weight referred to here is calculated by correcting the number average molecular weight determined by the vapor pressure equilibrium method with the amount of free phenol. As mentioned above, the molar ratio of catalyst A/catalyst B is set at 0.02 to 4.The reason for this is that if it is less than 0.02, the yield will be extremely reduced, while if it is more than 4, it will cause gelation. This is because it is dangerous. The 0/P ratio of the phenolic resin obtained by the present invention is within the range of ordinary random novolac (0
/P = 0.7 to 0.8), and therefore, among the molding properties of the molding material of the molding material using this resin, one with particularly excellent fast curing properties and excellent fluidity and meltability is It has the characteristic that it can be obtained.

Therefore, when this resin is applied to a molding material, since the resin melts at a low temperature, it has characteristics such as excellent thermal stability in the injection cylinder, good fluidity in the mold, and quick curing. Therefore, it becomes possible to shorten the molding time for large-volume molding (high-cycle molding). Also, because it has excellent fluidity and meltability,
There is no need to incorporate a plasticizer, and problems such as mold cloudiness and cloudiness of the molded product are eliminated.Next, the manufacturing method of the present invention will be explained below with reference to Examples.

Example 1 First, phenol 2829 and 37% formalin 2079
(F/P=0.85) is refluxed for 3 hours in the presence of 1.969 g of zinc chloride and 0.11 g of manganese acetate.

Next, water contained in formalin is removed under reduced pressure. Thereafter, the pressure was returned to normal and the temperature was raised stepwise to 150° C. over 3 hours to obtain 285 g of resin (101% based on the charged phenol). The free phenol content of this resin is 7.0'%. 0A)
The ratio was 1.1. In addition, 15 parts of hequinamethylenetetramine was added to 100 parts of this resin, and the gel time (hereinafter referred to as gel time) measured on a hot plate at 150°C was 43.
In addition, for 100 parts of this resin, 18 parts of hexamethylenetetramine, 65 parts of wood flour, and 2 parts of calcium carbonate were added.
5 parts of stearic acid and 3 parts of stearic acid were blended and kneaded for 5 minutes with heated rolls at 100°C to obtain a molding material.

The Barcol hardness of a molded article made of this material was 52.

When a conventional acid-catalyzed random novolak is used, the Barcol hardness is 25 for the same formulation. Example 2
Phenol 2829 and 88% paraform 81B9 (F/
P=0.80) with 1.6 g of zinc chloride and 0.66 g of zinc acetate.
g in the presence of 100℃ from room temperature for 30 minutes.
The temperature was gradually raised from 00° C. to 150° C. over 1 hour, and then the pressure was maintained at reduced pressure (80 blades? IELg) for 20 minutes and taken out onto a vat.

289 g of resin with free phenol of 7.69, α pre-ratio of 1.5, and gel time of 37 seconds was obtained. Further, when made into a molding material in the same manner as in Example 1, the barcol hardness was 55.Example 3 Phenol 2821 and 37% formalin 1871 (F/
P-0.77) with 0.8 g of manganese nitrate and 1.0 g of zinc acetate.
Resin 28 was reacted in the same manner as in Example 1 in the presence of 9,9.
I got 69.

This resin has a free phenol content of 6.0% and an O/P ratio of 2.0%.
0) Gel time was 23 seconds. When made into a molding material in the same manner as in Example 1, the Barcol hardness was 60.Next, in order to prove the effect of the manufacturing method of the present invention, Comparative Example 1 was prepared.
〜3 will be described.

Comparative Example 1 Phenol 2829 and 3770 Formalin 2249 (F
/P=0.92) in the presence of 2.1 g of zinc chloride in the same manner as in Example 1, and the temperature was raised to 150°C.

Thereafter, unreacted phenol was removed under reduced pressure (80 m77!Hg) for 45 minutes and taken out. Free phenol 7.8
%, O/P ratio 1.2, gel time 45 seconds resin is 260
g was obtained. This resin is equivalent to Example 1, but the yield is low (92% based on the phenol charged).

Moreover, compared to Examples 2 and 3, the O/P ratio was low and the fast curing property was inferior.

Comparative Example 2 282 g of phenol and 3770 formalin 1709 (F
/P=0.70) was reacted in the same manner as in Example 1 in the presence of 3.3 f1 of zinc acetate, and a rapid reaction occurred at an internal temperature of 145° C., resulting in gelation.

Comparative example 3 Phenol 2829 and 37% formalin 19
41 (F/P=0.80) was refluxed for 4 hours in the presence of 1.99 g of zinc acetate, and 1.19 g of oxalic acid was added.

After refluxing for 2 hours, the water contained in formalin was removed under reduced pressure, and the mixture was heated to 150° C. under normal pressure to obtain resin 2749. Free phenol of this resin is 7.2
%, O/P ratio 1.1, and gel time 49 seconds. This resin was the same as Example 1, but the reaction time was 2 hours longer.

Claims (1)

[Claims] 1 Molar ratio of phenols and formaldehyde is 0.6
Manganese acetate, zinc acetate or barium acetate as catalyst A effective for addition reaction selected from divalent metals in the range of ~0.95; catalyst B effective for condensation reaction as zinc oxide, manganese nitrate or A method for producing a fast-curing phenol resin, which comprises selecting one type of zinc chloride and reacting them in combination.