JP3207411B2 - Method for producing phenolic co-condensation resin - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for efficiently producing a novel thermosetting phenolic co-condensation resin. More specifically, the co-condensation rate is remarkably high and is a co-condensation resin having a low content of salts, and has excellent durability, heat resistance, hydrolysis resistance, rapid curing properties, flame retardancy, molding materials, laminates, The present invention relates to a phenol-amino co-condensation resin which is industrially useful as an adhesive, a foam or the like.

(Prior art) Conventionally, a phenol resin obtained by condensing phenol and formaldehyde, which are thermosetting resins, and a melamine resin obtained by condensing melamine and formaldehyde, are used as molding materials,
It is widely used industrially as a laminate and the like. Generally, phenolic resins have excellent durability, heat resistance, and hydrolysis resistance, but have the disadvantage that curing is slow. Amino resins such as melamine resins have good curability, but have insufficient durability, heat resistance and hydrolysis resistance.

(Problems to be Solved by the Invention) Therefore, a co-condensation resin having both advantages is
Was desired. However, a mere mixture of the two provides little improvement in performance, and the resin is easily separated during storage. Therefore, co-condensation resins of phenol and amino compounds have been studied.However, since the condensation reaction between amino compounds usually takes precedence over the co-condensation reaction between phenols and amino compounds, it is extremely difficult to produce a resin having a high co-condensation rate. Was. And the co-condensation resin in which the bond between amino compounds is generally inferior to the bond between phenols and amino compound or the bond between phenols in heat resistance and hydrolysis resistance, so that a large amount of bonds between amino compounds is present, The durability is close to that of the amino resin, and the cocondensation resin is not sufficiently improved. The rapid development of instrumental analysis technology in recent years has made it possible to quantitatively determine the existence ratio of self-condensation of phenol and amino compounds and of co-condensation between phenol and amino compounds in phenol-amino compound co-condensation resins. However, in the conventionally known production method, the co-condensation ratio is 0%.
It was as low as ~ 2%.

(Means for Solving the Problems) As a result of intensive studies on the relationship between the condensation reaction conditions of phenols and amino compounds and the cocondensation rate, the present inventors have found that the initial condensate of phenols and aldehydes and urea It was found that a co-condensation product of a phenol and an amino compound having excellent curability and durability can be easily obtained by reacting in an acidic aqueous solvent to thereby improve the co-condensation rate. (Japanese Unexamined Patent Application Publication No.
-95152). However, according to a subsequent study, salts such as sodium sulfate were produced as by-products and coexisted in this method, and this method was not yet satisfactory.

The present inventors have further studied a method for producing a co-condensation resin having a small amount of salts, and as a result, a resin having a small amount of salts and a high co-condensation rate can be obtained by a method of performing the reaction in two stages. The inventors have found that the object can be satisfied, and have accomplished the present invention based on this finding. That is, the present invention relates to a phenol, one or more compounds selected from the group consisting of a compound A obtained by reacting a phenol and an aldehyde, an amino compound (excluding melamine), and an amino compound (excluding melamine). ) And aldehydes are reacted with at least one compound selected from the group consisting of compound B, so that at least compound B is selected, the reaction is carried out under acidic conditions, and then the reaction is carried out under alkaline conditions. To provide a method for producing a phenolic co-condensation resin.
According to the present invention, the cocondensation rate defined as follows is 20%
Above, the amount of salts in the co-condensation resin is based on the amount of resin,
A phenolic co-condensation resin having a content of 5% by weight or less can be easily obtained.

In the production method of the present invention, if the cocondensation rate (the ratio (%) of the methylene groups derived from the cocondensation of the phenol-amino compound to all the methylene groups) is less than 20%, the performance is not sufficiently improved. is there. The upper limit of the co-condensation rate is not particularly limited, but if it exceeds 90%, the reaction step becomes complicated and may become economically disadvantageous, which is not preferable.

The co-condensation ratio can be easily known by ¹³ C-NMR analysis. Phenol and amino compounds -CH ₂ -, - CH ₂ -
O-CH ₂ - is like is attached via a methylene group (-C
The location of the signal of H ₂ −) is 30 to 100 ppm. Among them, signals based on co-condensation were 40.5, 44.2, 46.2, and 49.2 ppm.
Present nearby. In other words, for an integrated intensity of 30-100 ppm
The ratio of the sum of the signal intensities around 40.5, 44.2, 46.2, and 49.2 ppm is the cocondensation rate.

In the present invention, the salts in the co-condensation resin are salts obtained by reacting an acidic catalyst and an alkaline catalyst generated by raising and lowering the reaction pH, and examples thereof include sodium sulfate, sodium acetate, and calcium acetate.

When the amount of the salt exceeds 5% by weight, various performance problems such as a decrease in storage stability at a low temperature, a decrease in durability under a wet condition, a decrease in a curing speed, and a color stain occur. Needless to say, including a large amount of components that do not contribute to curing is disadvantageous in terms of cost. And removing salts is not easy.

Hereinafter, the method for producing the phenolic co-condensation resin which is the thermosetting resin of the present invention will be specifically described.

The phenols used in the present invention are phenol,
One or more selected from the group consisting of resorcinol, catechol, phenylphenol, and alkylphenol. The alkylphenol is a phenol to which an alkyl group having 12 or less carbon atoms is added, and specific examples thereof include cresol, xylenol, p-tert-butylphenol, p-octylphenol, mesitol, methylphenol and the like.

Amino compounds include urea, thiourea, guanamines,
One or more selected from the group consisting of guanidines and hydantoins. Guanamines are compounds in which one amino group of melamine is substituted with a hydrogen atom, an aliphatic / aromatic hydrocarbon or a derivative thereof, and examples thereof include formomoguamamine, acetoguanamine, benzoguanamine, and phenylacetoguanamine. Guanidines are guanidine and its salts, and examples thereof include guanidine hydrochloride and guanidine acetate. Hydantoins are hydantoin and hydantoin derivatives, and examples of hydantoin derivatives include dimethylhydantoin, diethylhydantoin, and hydantoin acetic acid.

Aldehydes are formaldehyde, acetaldehyde, n-butyraldehyde, paraformaldehyde,
And trioxane.

Compound A in the above reaction components is obtained by reacting aldehydes and phenols, preferably in a molar ratio of 0.5 to 2.0: 1. When the reaction molar ratio is less than 0.5, the physical strength of the co-condensation resin becomes insufficient, and when it exceeds 2.0, unreacted aldehydes increase, which is not preferable. Reaction pH
Is preferably 8.0 to 13.0. If it is lower than 8.0, the molecular weight tends to be high, and if it exceeds 13, the salts of the final product increase. Examples of the basic catalyst include alkali metal compounds such as hydroxides and oxides of alkali metals, alkaline earth metal compounds such as hydroxides and oxides of alkaline earth metals, and amine compounds. For example, NaOH, KOH, Ca (O
H) ₂ , CaO, Mg (OH) ₂ , ammonia and the like. The weight average molecular weight of compound A is desirably 1000 or less. If it is more than 1000, insolubles are liable to be formed during the reaction with the above reaction components, which is not preferable.

In the above reaction components, compound B is an essential component of the present invention, and is obtained by reacting an aldehyde with an amino compound, preferably at a molar ratio of 2.0 to 10.0: 1, pH 1 to 3.9. pH
If it is lower than 1.0, the amount of alkali catalyst required in the subsequent reaction step increases and the amount of salts in the resin increases, which is not preferable. 3.
If it is higher than 9, it may be undesirably cured during the reaction. The compound B preferably has a weight average molecular weight of 500 or less. If it exceeds 500, the viscosity of the co-condensation resin may be extremely high, which is not preferable.

The reaction components are one or more selected from the group consisting of phenols and compound A, and it is desirable that the ratio of phenols is large. If the ratio of compound A is large, the amount of salts in the final product will increase. Preferably, compound A is less than 50% by weight.

The reaction component is one or more selected from the group consisting of an amino compound and a compound B, and the compound B is an essential component. It is desirable that the ratio of the compound B is 50% by weight or more of the whole mixture.

The reaction molar ratio with the reaction components is the ratio of phenols to amino compounds, preferably 10: 1 to 1:10, and the total ratio of aldehydes, phenols and amino compounds is 1 to 1.
5: 1. The reaction is performed in two stages. The first stage is a reaction in which co-condensation substantially occurs, and the second stage is a reaction in which co-condensation and self-condensation occur. The reaction temperature is preferably 1
The temperature of both the second stage and the second stage is 100 ° C. or less. The first-stage reaction must be performed under acidic conditions, and a pH of 1.0 to 5.5 is desirable.
More preferably, it is 2.0 to 5.0. If the pH is lower than 1.0, the reaction may be too fast to control, and if the pH is higher than 5.5, the reaction time may be longer. As the acidic catalyst, mineral acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid, organic acids such as acetic acid, formic acid, phthalic acid, maleic acid and oxalic acid, and salts thereof which can make the reaction solution acidic can be used.
The second stage reaction must subsequently be carried out alkaline. The reaction pH is desirably 8.0 to 13.0. As a catalyst,
Alkali metal compounds such as hydroxides and oxides of alkali metals, alkaline earth metal compounds such as hydroxides and oxides of alkaline earth metals, and amine compounds are used. For example
Examples include NaOH, KOH, Ca (OH) ₂ , CaO, Mg (OH) ₂ , and ammonia. The reaction time varies depending on the reaction temperature, reaction pH, etc., and is not particularly limited, but the first-stage reaction is performed for several minutes or more,
Substantially co-condensation can then proceed to the second stage reaction.

The method of mixing with the reaction components may be arbitrary,
Is preferred. Moreover, it is also possible to add in portions.

Is preferably carried out in an aqueous solvent, but may contain a water-soluble organic solvent such as methanol, ethanol, acetone, isopropyl alcohol, or dioxane.

According to the method of the present invention, a white to pale red color having a viscosity of 0.1
This gives a resin liquid of up to 5 poise and a nonvolatile content of 35 to 65% by weight. There is no problem even if the solid content is increased by distillation if necessary.

When the phenol-amino compound co-condensation resin of the present invention is actually used, it may be performed in substantially the same manner as a conventional alkali resol resin, but the heating time may be short because the curability is improved. Further, since the storage stability is improved, it can withstand long-term storage. The phenolic co-condensation resin of the present invention is lighter in color than the conventional phenolic resin, so that its use is expanded.

Further, depending on the required performance and the like, a conventional urea formaldehyde resin, melamine formaldehyde resin, isocyanate-based resin or the like may be used as a mixture.

If necessary, additives such as fillers, extenders, preservatives, and coloring agents can be added.

(Function) According to the present invention, it is possible to obtain a phenolic co-condensation resin which is inexpensive, fast cures, has excellent durability, hydrolysis resistance, flame retardancy, and has a small amount of salts, which cannot be achieved by the prior art. it can.

(Examples) In order to more specifically show the present invention, examples are shown below, but the present invention is not limited by these examples.

Example 1 (Phenol-urea cocondensation resin) 120 g of urea and 486 g of 37% formalin were charged and dissolved in a reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel, and 50% sulfuric acid was added to adjust the pH to 2.0. After adjusting, 90 ℃
For 30 minutes. Add 190 g of phenol and 90 ℃
And reacted for 60 minutes. Then, the pH was adjusted to 9.4 by adding 25% sodium hydroxide, and the mixture was reacted at 90 ° C. for 60 minutes and cooled. The obtained resin liquid was pale red, had a viscosity of 150 cp, and had a nonvolatile content of 53% by weight. The cocondensation rate was 55%. The salt content was 2.4% by weight.

Example 2 (Phenolthiourea cocondensation resin) 152 g of thiourea and 486 g of 37% formalin were charged and dissolved in a reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel. After adjusting to 2.0, 9
The reaction was performed at 0 ° C. for 30 minutes. 234g of 80% phenol
The mixture was further reacted at 90 ° C. for 60 minutes. Then, the pH was adjusted to 9.4 by adding 25% sodium hydroxide, and the mixture was reacted at 90 ° C. for 60 minutes and cooled. The obtained resin liquid was pale yellow, had a viscosity of 50 cp, and had a nonvolatile content of 52% by weight. The cocondensation rate was 38%. The salt content was 2.4% by weight.

Example 3 (Phenolbenzoguanamine cocondensation resin) In a reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel, 152 g of benzoguanamine and 37% formalin 48 were added.
6 g and 150 g of water were charged and dissolved, and then 50% sulfuric acid was added to adjust the pH to 2.5.
Then, the reaction was carried out at 90 ° C. for 30 minutes. Further, 234 g of 80% phenol was added and reacted at 90 ° C. for further 60 minutes. Then, the pH was adjusted to 9.4 by adding 25% sodium hydroxide.
The reaction was performed for 20 minutes. The resin liquid obtained by cooling the resin liquid is:
It was pale red, had a viscosity of 45 cp, and had a nonvolatile content of 46% by weight. The cocondensation rate was 32%. The salt content was 2.6% by weight.

Reference Example 1 (Compound A-1) In a reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel, 188 g of phenol, 37% 405 g of formalin, 405 g of 25%
35.4 g of NaOH was charged and dissolved while cooling, then reacted at 75 ° C. for 4 hours, and then cooled to 35 ° C. This is compound A
-1.

Reference Example 2 (Compound A-2) In a reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel, 220 g of resorcinol, 405 g of 37% formalin,
After charging 22.4 g of 25% NaOH and dissolving while cooling, 70
After reacting at 35 ° C for 2 hours, it was cooled to 35 ° C. This is designated as compound A-2.

Reference Example 3 (Compound B-1) 130 g of thiourea, 486 g of 37% formalin, and 20.0 g of 50% sulfuric acid were charged and dissolved in a reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel. After reacting for 1 hour, it was cooled to 35 ° C. This is designated as compound B-1.

Reference Example 4 (Compound B-2) In a reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel, 191 g of guanidine hydrochloride, 486 g of 37% formalin,
After adding and dissolving 7 g of 50% sulfuric acid, the mixture was reacted at 70 ° C. for 1 hour and cooled to 40 ° C. This is designated as compound B-2.

Reference Example 5 (Compound B-3) 364 g of benzoguanamine, 37% formalin 486 was placed in a reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel.
g, 50% sulfuric acid (22.0 g)
After reacting at 35 ° C for 1 hour, it was cooled to 35 ° C. This is designated as compound B-3.

Example 4 A reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel was charged with 1,30 g of compound A, 100 g of phenol, 1,350 g of compound B, and 6 g of urea, and 50% sulfuric acid was added to adjust the pH to 2.0.
After adjusting to 90 ° C., the reaction was carried out at 90 ° C. for 30 minutes. Then, the pH was adjusted to 9.4 by adding 25% sodium hydroxide, and the mixture was reacted at 90 ° C. for 60 minutes. The resin liquid obtained by cooling the resin liquid had an orange color, a viscosity of 50 cp, and a nonvolatile content of 57% by weight. The cocondensation rate was 58%. The salt content was 3.1% by weight.

Example 5 A reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel was charged with 2,30 g of compound A, 100 g of phenol, 2,350 g of compound B, and 6 g of guanidine hydrochloride, and 50% sulfuric acid was added to adjust the pH to 2.0. After adjusting to 90 ° C., the reaction was carried out at 90 ° C. for 30 minutes. Then adjust the pH to 9.4 by adding 25% sodium hydroxide, and
The reaction was performed for 0 minutes. The resin liquid obtained by cooling the resin liquid is:
It was pale red, had a viscosity of 123 cp, and had a nonvolatile content of 56% by weight. The cocondensation rate was 43%. The salt content was 2.5% by weight.

Comparative Example 1 (Production of phenolic resin) A reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel was charged with 200 g of phenol, 517 g of formalin and 517 g of 25%.
42.4 g of NaOH was charged and dissolved while cooling, followed by a reaction at 80 ° C. for 2 hours, followed by cooling. The obtained resin liquid was red, had a viscosity of 34 cp, and had a nonvolatile content of 48% by weight. 3.8 salt
% By weight.

Comparative Example 2 (Production of Phenol Melamine Resin) In a reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel, 200 g of phenol, 517 g of formalin and 517 g of 25%
42.4 g of NaOH was charged and dissolved while cooling, and then reacted at 50 ° C. for 8 hours. After cooling to 45 ° C, 127 g of melamine
Was added and the mixture was reacted at 85 ° C. for 60 minutes and cooled. The obtained resin liquid was red, had a viscosity of 50 cp, and had a nonvolatile content of 50% by weight. The cocondensation rate was 1%. The salt content was 5.2% by weight.

Comparative Example 3 A reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel was charged with phenol 200 g, 37% formalin 517 g, 25%.
22.4 g of NaOH was charged and dissolved while cooling, followed by reaction at 50 ° C. for 8 hours. After cooling to 45 ° C, 127 g of melamine
Was added and the mixture was reacted at 85 ° C. for 60 minutes and cooled. The obtained resin liquid was pale red, had a viscosity of 50 cp, and had a nonvolatile content of 50% by weight. The cocondensation rate was 1%. The salt content was 5.7% by weight.

Comparative Example 4 (Production of Urea Resin) A reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel was charged with 120 g of urea and 324 g of 37% formalin.
Adjust H to 8.6. After reaction at 85 ° C. for 15 minutes, 1N acetic acid was added to adjust the pH to 5.0. After reacting at 85 ° C for 1 hour, the pH is adjusted to 8.0 and cooled to 60 ° C. Further, 40 g of urea was added and reacted at 60 ° C. for 1 hour, followed by cooling. The obtained resin liquid was white, had a viscosity of 40 cp, and had a salt content of 2.4% by weight.

Reference Example 6 (Production of phenol urea co-condensation resin) A reaction flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel was charged with 200 g of phenol, 517 g of 37% formalin, and NaOH.
Was dissolved while cooling, and then reacted at 50 ° C. for 8 hours. After cooling to 35 ° C., 125 g of 50% sulfuric acid was dropped from the dropping funnel. At this time, the pH was 3.5. Then, 127 g of urea was added, and the mixture was reacted at 85 ° C. for 60 minutes and cooled. After the reaction, the mixture was neutralized with sodium carbonate. The obtained resin liquid was red, had a viscosity of 50 cp, and had a nonvolatile content of 50% by weight. Cocondensation rate is 30
%was. The salt content was 15% by weight.

Test Example The performance of each resin obtained as described above was tested as follows.

[Measurement of curing speed] The curing behavior of each resin was measured using TBA (Torsional Braid Analisis:
The measurement was performed using a rheograph TBA manufactured by Toyo Seiki. G
(Stiffness modulus) is proportional to the storage modulus, and λ (logarithmic decrement) is a number proportional to tan δ, which is the ratio between the storage modulus and the loss modulus. The change in G is approximately proportional to the degree of cure. The result is shown in FIG.

[Production of Particle Boat] Each resin was applied to a chip according to a conventional method to produce a particle boat, and a performance test was performed.

Board thickness: 15mm Density: 0.68 Chip moisture content: Surface layer 12%, core layer 3% Resin spray rate: surface layer 12%, core layer 3% Heat pressure temperature: 145 ° C, 165 ° C Heat pressure time: 3 minutes, 5 minutes Clamping pressure: 28 kgf / cm ² Wood chips: Rawan ring flakes [Storage stability] When stored in a constant temperature room at 5 ° C, in Reference Example 6, crystals precipitated after 3 weeks, but Examples 1 to 7 and Comparative Example 1 No. 4 has not changed for more than one month.

(Effect of the Invention) The phenol-amino co-condensation resin of the present invention is shown in Table 1,
As shown in FIG. 1, it has a rapid curing property equal to or higher than that of a conventional amino resin, and also shows heat resistance equivalent to that of a conventional phenol resin. Furthermore, when the phenol melamine of the present invention is used as an adhesive for a co-condensation resin particle board,
As shown in Table 2, excellent board physical properties can be obtained even by hot pressing at a low temperature for a short time as compared with the conventional resin.

Further, the resin of the example of the present invention has improved adhesive performance as compared with the resin of JP-A-3-95152 (Reference Example 6).
Although the theoretical background of the performance improvement is not clear, it is thought to be related to the decrease in the amount of salt. In addition, storage stability was improved.
The cutability by the circular saw was better in the example than in the reference example 6.

[Brief description of the drawings]

FIG. 1 shows the rigidity G of each resin of the example and the comparative example.
6 is a graph showing a logarithmic decay rate λ.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-142907 (JP, A) JP-A-49-34997 (JP, A) JP-A-49-34998 (JP, A) 243613 (JP, A) JP-A-3-265619 (JP, A) JP-B-43-28479 (JP, B1) US Patent 3,364,167 (US, A) UK Patent 1,057,400 (GB, A) (58) (Int.Cl. ⁷ , DB name) C08G 14/00-14/14 C08G 8/00-8/38 C08G 12/00-12/46 CA (STN) REGISTRY (STN)

Claims (7)

(57) [Claims] 1. A compound selected from the group consisting of phenols and compound A obtained by reacting phenols and aldehydes.
At least one compound selected from the group consisting of an amino compound (excluding melamine) and a compound B obtained by reacting an amino compound (excluding melamine) with an aldehyde; A method for producing a phenolic co-condensation resin, wherein the phenolic co-condensation resin is reacted under an acidic condition and then under an alkaline condition. 2. A compound B comprising an amino compound and an aldehyde.
(1) An initial reaction product reacted at pH 1.5 to 3.9.
A method for producing a phenolic co-condensation resin. 3. The compound according to claim 1, wherein the molar ratio of the reaction between the amino compound of compound B and the aldehyde is 1: 2 to 10.
A method for producing a phenolic co-condensation resin. 4. The process for producing a phenolic co-condensation resin according to claim 1, wherein an aldehyde is added at any stage of the reaction. 5. The process for producing a phenolic co-condensation resin according to claim 1, wherein the reaction molar ratio of the phenols to the amino compound with the reaction components is from 10: 1 to 1:10. 6. The process for producing a phenolic co-condensation resin according to claim 1, wherein the total molar ratio of the aldehyde, the phenol and the amino compound to the reaction component is 1 to 5: 1. 7. The phenolic co-condensation resin is a condensate of a phenol, an amino compound and an aldehyde, wherein the proportion of methylene groups derived from the co-condensation of the phenol-amino compound in all methylene groups is 20%. The method for producing a phenolic co-condensation resin according to claim 1, wherein the amount of salts in the obtained co-condensation resin is 5% by weight or less based on the amount of the condensation resin.