JPS6236047B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a resol type solid phenolic resin with excellent thermal stability. Resol-type solid phenolic resins can be heat-cured without the use of curing agents such as hexamethylenetetramine, and their use as binders for inorganic and organic materials is increasing year by year. Conventionally, various methods have been adopted as industrial methods for manufacturing this type of phenolic resin, such as the cooling pan method, underwater drop method, and spray drying method, but each method has problems in terms of physical properties or productivity. However, it has various drawbacks and cannot be said to be effective as an industrial means. In other words, the most important thing in producing this type of solid phenolic resin is that the reaction rate is high and the viscosity of the reaction system increases rapidly at the end of the reaction. The important issues are to prevent the gelation phenomenon caused by self-condensation reaction and to quickly remove the resin from the reaction vessel, but each of the conventional methods has several problems that need to be solved. be. First, in the case of the above-mentioned cooling pan method, it is necessary to quickly stop the self-condensation reaction of the resin that has been reacted until a predetermined gel time in the reaction pot.
The resin is taken out to a cooling pan or steel belt that has been cooled to ~10°C, but there are inconveniences such as differences in physical properties such as gel time or flow of the resin obtained in the first and second half of the removal process. There is a thing. In addition, in order to prevent the exothermic gelation caused by self-condensation of the resin during removal as described above, it is necessary to keep the resin thickness to 20 mm or less, and the area required for laying the cooling pan is approximately 30 cm ² per ton of resin. This is also one of the drawbacks of the cooling pan method. Next, in the case of the above-mentioned underwater dropping method, since this is a method in which the resin that has been reacted in the reaction pot until a predetermined gel time is reached is dropped into the water of the bit and taken out, the resin temperature decreases. Although this is an effective measure, there are other problems such as drainage problems due to the dispersion of free phenols and low-molecular compounds (low-degree condensates) into water, and secondary drying to remove moisture from products. There are drawbacks such as the need for solutions that must be taken. Furthermore, in the case of the above-mentioned spray dryer method, both atomization equipment and drying equipment are required, which not only increases the size of the equipment but also requires a large amount of extra heat. There are drawbacks such as a decrease in performance and a decrease in yield. However, as a result of intensive research into a method for producing a resol-type solid phenolic resin that is free from the risk of gelation during resin removal in the prior art, the present inventors found that a specific alkyl phenol or polyhydric phenol and a formaldehyde supply method were developed. By first obtaining an initial condensate from a substance and then adding phenol to this initial condensate for reaction, it is possible to produce the product in a known and commonly used reaction vessel as is, and also to produce various products that have been used in the past, such as those mentioned above. In addition to being able to use the resin extraction method described above, we have found a method for producing resol type solid phenolic resin that does not have the risk of gelation due to self-condensation reactions in the reaction pot or on the cooling pan, and has a long pot life. As a result, we have completed the present invention. That is, the present invention uses 1 mole of an alkylphenol or polyhydric phenol having a linear or branched alkyl group at the ortho or para position of the phenol, and 1.0 to 1.0 to 1 mole of polyhydric phenol in terms of formaldehyde.
3.0 of formaldehyde feed material is reacted in the presence of a basic catalyst until the amount of unreacted free alkyl phenol becomes 10% by weight or less, and then the formaldehyde content and the alkyl phenol (or (phenol) and the co-condensed component (phenol) is
A resol type method consisting of adding phenol to a concentration of 0.8 to 1.5%, allowing the reaction to occur until the amount of free formaldehyde in the system reaches 1.0 to 5.0% by weight, and then distilling off water and unreacted components in the system. The present invention provides a method for producing solid phenolic resin. Here, typical alkylphenols used in the first stage reaction are o
- or p-cresol, 2, 3-, 2, 4
-, 2,5- or 3,4-xylenol, p
-tert-butylphenol, p-tert-amylphenol, p-octylphenol, etc., and these may be in either the ortho or para substitution position with respect to the -OH group in the phenol. On the other hand, typical polyhydric phenols mentioned above include bisphenol-A and bisphenol-S. Further, typical formaldehyde supplying substances include formalin, paraformaldehyde, or hexamethylenetetramine at a concentration of 37 to 50% by weight. Furthermore, the above-mentioned basic catalyst may be appropriately selected from known and commonly used catalysts such as alkali metals or alkaline earth metals and their hydroxides, primary, secondary or tertiary amines, aqueous ammonia, etc. It will be done. These catalysts can be used alone or in a mixture, but
Preferably mixed catalysts are suitable. In carrying out the process of the invention, the molar ratio of formaldehyde feed material to one mole of alkylphenol or polyhydric phenol ranges from 1.0 to 3.0, preferably from 2.0 to 2.5 moles. This molar ratio
When it is less than 1.0, the addition rate to alkylphenol (or polyhydric phenol) decreases and the free alkylphenol content or polyhydric phenol content becomes high, and conversely, when it exceeds 3.0, the formaldehyde content increases. Although it is effective in terms of reducing free alkyl phenols or polyhydric phenols, the free formaldehyde content becomes abnormally high, which necessitates an increase in the amount of phenol added as a secondary additive component, and in the end, the amount of alkyl phenols (or Since the ratio of (polyhydric phenol)/phenol becomes low, it cannot be said to be preferable in terms of synthesis. On the other hand, when carrying out the method of the present invention, the molar ratio of the formaldehyde component in the reaction system to the co-condensed component of alkyl phenol (or polyhydric phenol) and phenol is 0.80 to 1.50, preferably 0.9.
~1.0 range. If this ratio is less than 0.8, the resulting resin will take a long time to cure, while if it exceeds 1.5, partial gelation may occur, both of which are undesirable. In carrying out the method of the present invention, the reaction between the alkyl phenol or polyhydric phenol and the formaldehyde supply substance in the first stage is carried out under reflux (95 to
100°C), and the temperature of the reaction carried out with the addition of phenol in the second stage is suitably in the range of 60 to 80°C. The thus obtained solid resol resin of the present invention has a long pot life and excellent thermal stability, so it can be used for inorganic and organic materials such as dry hot binders, felt binders, and rock wool binders. It has a wide range of uses as a binder. Next, the present invention will be specifically explained using examples. Hereinafter, all parts and percentages are based on weight unless otherwise specified. Example 1 1000 parts of P-tert-butylphenol and 1204 parts of 41.5% formalin were charged into a reaction vessel and stirring was started. Next, 100 parts of 25% ammonia water was gradually added at a temperature below 30°C, and the mixture was heated to reflux temperature and reacted for 120 minutes. At this point, the free P-tert-butylphenol content was 8.5%. Thereafter, 683 parts of phenol was added dropwise over about 30 minutes, and the reaction was carried out at 50 to 60°C until the free formaldehyde content was reduced to 2%. Next, the content liquid was cooled to 50°C or lower and separated by standing, 900 parts of the upper layer water was removed, and then 720 parts of water was removed.
Start dehydration at a reduced pressure of ~760 mmHg, then
Dehydration was continued while raising the temperature to 100°C, and the contents were taken out onto a cooling pan with a resin thickness of 50 mm. During this time, the workability of removing the resin from the pot and
We carefully observed the heat generation of the resin after panning out 50mm, but no abnormalities were observed. The physical properties of the resin thus obtained are shown below.
The gel time at 150°C was 32 minutes, the flow was 150 mm or more, and the softening point by the ring and ball method (hereinafter the same) was 85°C. Example 2 1000 parts p-cresol and 41.5% formalin
Pour 2010 parts into the reaction vessel, start stirring, gradually add 100 parts of 25% aqueous ammonia at a temperature below 30°C, and carry out the reaction at 80°C for 2 hours. The free p-cresol content is 6.2%. It became. Next, the same operation as in Example 1 was repeated except that 1254 parts of phenol was added, and no abnormalities such as gelation or heat generation were observed. The resin thus obtained had a gel time of 22 minutes at 150°C, a flow of 145 mm, and a softening point of 88°C. Example 3 The same operation as in Example 2 was repeated except that 40 parts of triethylamine and 100 parts of 25% aqueous ammonia were used as catalysts, but no abnormalities such as gelation or heat generation were observed. . The resins thus obtained each had a gel time of 15 minutes at 150°C, a flow of 145 mm, and a softening point of 85°C. Application Example This example shows an example of an application test conducted to obtain a so-called fast-curing resin composition having a gel time suitable for use with various binders. For each resin (resol type solid phenolic resin), a novolac type phenolic resin "Fandretsu TD-3420" (Dainippon Ink & Chemicals Co., Ltd. Co., Ltd. product) and the ratio of solid resol resin to novolac resin was changed stepwise to observe and measure the length of gel time. The results are shown below.

[Table] The results of applying the solid resol resin obtained above, which is a secondary blend of novolac resin, as binders for felt and casting, respectively, show that the resin obtained by the method of the present invention is superior to novolac type phenolic resin. However, it was no different.

Claims (1)

[Claims] 1 1 mole of an alkylphenol or polyhydric phenol having a linear or branched alkyl group at the ortho or para position of the phenol and 1.0 to 3.0 moles of formaldehyde supply material in terms of formaldehyde are combined with a basic catalyst. is reacted in the presence of unreacted free alkylphenol or polyvalent phenol until the amount becomes 10% by weight or less, and then the formaldehyde content in the reaction system and the alkylphenol or polyvalent phenol and the co-condensed component of phenol are reacted. The molar ratio of is 0.8
1.5 to 1.5% by weight, the reaction is carried out until the amount of free formaldehyde in the system becomes 1.5 to 5.0% by weight, and then water and unreacted components in the system are distilled off. A method for producing a resol type solid phenolic resin with excellent thermal stability.