JPS63150317A - Production of resol phenolic resin - Google Patents

Abstract

PURPOSE:To obtain a resin remarkably low in a low-molecular phenol component content and useful for, especially, a can interior paint, by reacting a specified capped epoxy resin with formaldehyde in the presence of a basic catalyst. CONSTITUTION:An epoxy resin of a mol.wt. of 350-6,000 and an epoxy equivalent of 150-4,000, preferably, of a mol.wt. of 350-1,000 and an epoxy equivalent of 150-700 is reacted with a bisphenol to prepare an epoxy resin of an epoxy equivalent >=500, preferably, >=10,000, wherein at least one of its terminals is chemically bound to the bisphenol. The obtained capped epoxy resin is dissolved in an organic solvent and subjected to resol formation reaction in the presence of formaldehyde to obtain the purpose resin.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a resol type phenolic resin having a novel resin structure.

As is well known, resol type phenolic resins are made from carbonic acid, bisphenol A, etc., and are converted into methylol by reacting formaldehyde in the presence of a basic catalyst.
It is synthesized by increasing the molecular weight. Such phenolic resins have thermosetting properties and are widely used as curing agents, and in recent years have been known to be useful as paints for the inside of cans when combined with epoxy.

However, conventional phenolic resins contain many low-molecular-weight components, and problems that are thought to be caused by this, such as KMnO4 consumption, flavor, and tar in paint for the inside of cans, have been pointed out. It is.

Therefore, the present inventors have conducted intensive studies to solve these problems, and have found that an epoxy resin obtained by combining bisphenols with polychlorohydrin and bisphenols can be used at one or both ends. Resol-type phenolic resins, which are obtained by reacting formaldehydes with epoxy resins whose terminal ends are bisphenols (hereinafter referred to as "capped epoxy resins"), in the presence of a basic catalyst, have overcome the drawbacks of conventional resins. We found that it can be improved. In other words, this invention converts a capped epoxy resin into a resol, and the resol-forming raw material itself is polymeric compared to conventional methods. Therefore, it necessarily contains very little low-molecular weight phenol components, and is particularly effective in improving extractability, which is a problem in paints for cans and the like.

Method for producing the resol type phenolic resin! I+:, 2・
It consists of the following steps. Step @1 is the synthesis of an epoxy resin in which bisphenols are reacted at one or both ends, a so-called capped epoxy resin, which is a molecule obtained by combining bisphenols and epichlorohydrin! 350-6,000 t150-4,00 per epoxy
0 Preferably molecular weight 350 to 1,000 epoxy and 1i
Epoxy equivalent of 500 or more by reacting bisphenols with epoxy resin of 150 to 700,
Preferably, an epoxy resin having an epoxy molecular weight of 11 (1,000 or more), in which bisphenols are substantially reacted at one or both ends, is synthesized. Second step 4 is a resolization step. The capped epoxy resin obtained in the process is dissolved in an organic solvent, and then formaldehyde is added in the presence of a basic catalyst to perform a resolization reaction.As the organic solvent, alcohols such as n-butyl alcohol, butyl cellosolve, etc. A catalyst that dissolves the capped epoxy resin can be used, such as cellosolve type.Basic catalysts include metal alkalis such as sodium hydroxide and calcium hydroxide, which are well known as general resolization catalysts, phosphoric acid, etc. Basic salts such as sodium, amines such as triethylamine, etc. can be used.
Capped epoxy resin, 0.005 per mole
A range of 0.2 mol to 0.2 mol is desirable.

If it is less than 0.005 mol, the resolization reaction is extremely slow (,
If the amount exceeds 0.2 mol, residual catalyst in the resulting resin becomes a problem. The aldehyde is selected from formalin water, formaldehyde dissolved in an organic solvent, and paraformaldehyde, and the number of moles of formaldehyde relative to the number of moles of unknown bisphenols in the capped epoxy resin is 2 to
6, preferably 4-6. If it is 6 or more, the amount of free formalin in the produced resin is large, and there are serious problems such as irritating odor.

Also, if it is 2 or less, resolization is not progressing sufficiently.

It is difficult to achieve the objectives of the period.

The resol type phenolic resin synthesized by the above method has a feature that it has a considerably lower low molecular weight TG content than the resol type phenol resin synthesized from conventional bisphenols. It has been found that when used as fc, KMnO4 consumption, flavor properties, etc. are very excellent.

Next, examples will be shown and explained in more detail. Also examples,
"Parts" and "%" listed in Comparative Examples indicate "parts by weight" and "ruI'i%", respectively.

Example 1 228 parts of bisphenol A, 188 parts of Epikote 828 (epoxy resin epoxy resin manufactured by Shell F188), and 0.1% of tri-n-butylamine were charged into a reaction vessel equipped with a stirrer and a reflux condenser, and the temperature was raised to 160°C. The reaction was carried out for 4 hours to synthesize a bisphenol A-terminated epoxy resin having an epoxy weight of -310,500.

Next, after cooling the yarn, 229 parts of n-butanol was added to dissolve the capping epoxy resin, and further IN-NaoH2
Add 2 parts. Then, 324 parts of 37% formalin water was added, the temperature was raised to 90°C, and a resolization reaction was carried out for 4 hours. Then the solvent is washed and separated by water, after draining the water;
Be sure to heat at a reduced pressure of 650 mmHf to remove water, solvent, and formalin. When the concentration reached 70%, it was diluted to 55% with n-butanol to obtain a resol (phenolic resin) with a weight average molecular weight of 3200.

Example 2 163 parts of bisphenol A, 828,188 parts of Epicoat, 0.1% of 17-fi-butylamine, and 38 parts of butyl cellosolve were placed in a reaction vessel equipped with a stirrer and a reflux condenser, and reacted at 160°C for 4 hours to form a mixture of epoxy and F114.
Synthesize OOO bisphenol A-terminated epoxy resin. After cooling the system, 160 parts of n-butanol was added to dissolve the capped epoxy resin, and then 1N-NaOH was added.
Add 46 parts. Then:) 348 parts of 7% formalin water was added, the temperature was raised to 90°C, and the resolization reaction was carried out for 6 hours.

Next, the solvent to be separated was washed with water, and after the water was discharged, it was heated at a reduced pressure of 650 mmHf to perform dehydration, solvent removal, and free formalin. When the concentration reached 65%, it was reduced to 55% with n-butanol. It was diluted to obtain a resolized phenolic resin with a weight average molecular weight of 4500.

Comparative Example 1 Bisphenol A 228 m, "-butanol 228
9.33 parts of triethylamine and 324 parts of 37% formalin water were placed in a reaction vessel equipped with a stirrer and a reflux condenser, heated to 90 to 95°C, and reacted with distant current stirring at 6:00 tm. Then, the mixture was heated at a reduced pressure of 650 mmHf to perform dehydration, deboiling agent, and removal of formalin. Consultation level 70
%, diluted to 55% with n-butanol.

Comparative Example 2 228 parts of bisphenol A, 228 parts of n-butanol,
7 Ammonia 5-0'SB and 324 parts of 37% formalin water were charged into a reaction vessel equipped with a stirrer and a reflux condenser.
The temperature was raised to 95°C and the reaction was carried out under reflux for 6 hours, and then 7 parts of phosphoric acid was added and the reaction was allowed to proceed at 80°C for 1 hour. Then,
After discharging the water to be separated, the degree of vacuum is 650 rnmH.
Dehydration, solvent removal, and removal of formalin were performed by heating at f. When a concentration of 70% was reached, it was diluted with n-butanol to 55%.

<Coating film performance test> Using the phenolic resins obtained in Examples 1 and 2 and Comparative Examples 1 and 2 above, water-based paints were prepared as follows.
The water-based paint was applied to one side of μ aluminum foil to a thickness of 8 to 10 μ, and then dried at an ambient temperature of 200° C. for about 30 seconds. The above water-based paint was also applied to the back side of the lid to a thickness of 8 to 10 μm, and then dried at an ambient temperature of 200° C. for about 80 seconds to prepare a test eyelid for a water extract flavor test.

The above water-based paint was coated on a 4#25 tin plate to a thickness of 8 to 10 μm, and then rotated for about 2 minutes at an ambient temperature of 200° C. to prepare a test panel.

Various test methods are shown below, and the test results are shown in Table 1 below.

[Preparation of water-based paint]

Formulation (1) Carboxyl group-containing acrylic resin solution *l
150 parts (2) Epoxy resin solution *2 283 parts (3) n-butanol 86 parts (4) 2-butoxycetanol 47 parts (5) Ashi ionized water
3.2 parts (6) Dimethylaminoethanol 5.3 parts (71) Dimethylaminoethanol 9.5 parts (seconds) Phenol resin solution obtained in Examples and Comparative Examples 10 parts Total 1240 parts*1 Methacrylic acid 17
4 parts, 87 parts of styrene, and 29 parts of ethyl acrylate, an acrylic resin with an acid value of 390 and a solid content of 30%*2 (Epicor) 828 (epoxy resin manufactured by Shell)
500 parts of bisphenol A, 286 parts of tri-n-butylamine, and 86 parts of methyl isobutyl ketone were placed in a 90% epoxy resin solution reactor.
It was heated to 15°C to dissolve the resin component. After dissolving 10
Cool to 5℃, add (5) to (6) in order, and heat to 105℃
It was held for 3 hours. The reaction product has a solid content weight ratio of acrylic resin/epoxy resin of 15/85. The reaction is
The acid value was measured and followed, and the acid value was 51 at the end of the reaction. Then, after 3 hours, (η) was added, and after 5 minutes, (8) was added and powder blended at 105°C for 30 minutes. Thereafter, (9) was added over 30 minutes to give a solid content of 25%.
A stable water-based paint was obtained.

(1) Adhesion Use a knife to make 11 vertical and horizontal cuts, each about 1.5 tm wide, on the coated surface of the test panel painted on tinplate. Adhere the tape with 24+w width of Seronon adhesive and observe the adhesion of the goblin part when it is separated by φ1.

○: No peeling at all, △: Slight peeling, ×: Significant peeling.

(2) Test panels painted on boiling water-resistant tinplate were treated underwater at 100℃ for 30 minutes, and the eardrums were removed visually and with adhesive tape (
Judgment is made using the same evaluation as for adhesion.

(3) KM, 104 consumption 100μ aluminum foil coated with various water-soluble paints, coating area: activated carbon coating In! Pour the water into a heat-resistant glass bottle at a ratio of 1-:1-, rinse it, and boil it at 12.5℃-3.
The test method described in the Food Sanitation Act (Ministry of Health and Welfare 4)
34%).

Consumption amount is expressed in PPM (4) Water extract flavor 100μ gamma foil coated with various water-based paints is placed in a heat-resistant glass bottle so that the coating area: tap water treated with activated carbon is 44:1 m. , Close the lid, and after sterilizing at 100℃ for 30 minutes, perform a flavor test on the liquid inside.2
゜○: No change at all, △: Slight change, ×: Significant change.

(5) Workability Using a special fold-type DuPont impact tester, a coated tin sample folded in half is placed at the bottom, and an iron weight with a flat contact surface weighing I kg is dropped from a height of 50σ. Measure the length of the crack in the paint film at the bent part at 9 o'clock. O: 0 to 10 parts, △: 10 to 20 parts, A 25mm plate was placed in a container equipped with a reflux condenser so that the ratio of chloroform to chloroform was 1d:1-, and heated, and the amount of residue after 1 hour from the start of reflux was expressed as a percentage.

Claims (1)

[Claims] 1. A capped epoxy resin obtained by reacting an epoxy resin obtained by condensation of bisphenols and epichlorohydrin with bisphenols, in which one or both ends are bisphenols, is used as a raw material, and a base A method for producing a resol type phenolic resin obtained by reacting formaldehydes in the presence of a chemical catalyst. 2. The epoxy resin has a molecular weight of 350 to 6,000 and an epoxy equivalent of 150 to 4,000, preferably a molecular weight of 350 to 1.
, 000 and an epoxy equivalent of 150 to 700. 3. The method for producing a resol type phenolic resin according to claim 1, wherein the capped epoxy resin has an epoxy equivalent of 500 or more, preferably 10,000 or more. 4. The basic catalyst is selected from metal alkalis such as sodium hydroxide and calcium hydroxide, basic salts such as sodium phosphate, amines such as triethylamine, etc. The resol type phenol according to claim 1 Method of manufacturing resin. 5. The method for producing a resol type phenolic resin according to claim 1, wherein the bisphenols are selected from bisphenol A, bisphenol F, and bisphenol S. 6. The method for producing a resol type phenolic resin according to claim 1, wherein the formaldehyde is selected from formalin water, formaldehyde dissolved in an organic solvent, and paraformaldehyde. 7. The number of moles of formaldehyde relative to the number of moles of terminal bisphenols in the capped epoxy resin is 2 to 6.
, preferably 4 to 6. The method for producing a resol type phenolic resin according to claim 1.