HU180488B - Method for producing liquid epoxy resins improved feature - Google Patents

Abstract

Low viscosity liq. epoxy resins which can be cured at room temp. in anhydrous or aq. medium are made by first reacting 0.1-1.0 mol. of 2,2-bis-(p-hydroxyphenyl)-propane and/or 0.1-1 mol. phenolic resin(s) with 1-4 mols epichlorhydrin and 0.3-4 mols. NaOH to form a precondensate, esp. with a viscosity of 5-50 cP at 25 degrees C. The NaCl formed is opt. removed with water and the water decanted. Condensn. of the resin is then effected under reduced pressure with distn. of excess epichlorhydrin until the prod. has an epoxy equiv. of 200-250 and a viscosity of 100-2000 cP at 25 degrees C. The NaCl formed is opt. removed with water, then 0.1-2 mols. 25 plus-or-minus 5% aq. NaOH soln. is added and the resin is further condensed at elevated temps. under reduced pressure, after which the volatile components are blown out with steam and >=1 inert gases and the condesn. is continued to the required viscosity. Process gives low viscosity liq. epoxy resins which can be used at room temp. with known epoxy curing agents either in anhydrous or aq. medium (e.g. as emulsions or dispersions).

Description

CHEMICAL Building Materials Company, Budapest

Process for the preparation of liquid epoxy resins with improved properties

FIELD OF THE INVENTION The present invention relates to a process for the preparation of epoxy resins having improved properties, liquid at ambient temperature and crosslinkable in both anhydrous and aqueous media. Epoxy resins have been playing an increasingly important role in the coating and bonding of a variety of structural materials such as metal, concrete, wood in recent decades. Their spread is due to the excellent chemical resistance, adhesion and excellent durability of epoxy resin-based varnishes, paints, adhesives, putty. Epoxy resins have good chemical properties due to their good chemical structure and structure and crosslinking agents.

Several processes for the production of epoxy resins have become known in the industry. These methods are described in more detail in, for example, Houben-Weyl, Methoden dér Organischen Chemie 15/2. , Macromolecular Stoffe 465-553. She. (1963);

Papquiin, A.M .: Epoxydverbindungen und Epoxyharze 306-457. She. (1958); and Potters, W.G. Epoxy Resins 9-37. She. (1970).

The preparation of epoxy resins is also described in detail in the patent literature, so reference is made to Hungarian Patent Nos. 154,181 and 157,237.

The processes described in the above mentioned literature correspond to the reaction of aromatic diols and epichlorohydrin in the production of epoxy resins in an alkaline medium. Of the 5 aromatic diols, 2,2-bis-p-hydroxylphenylpropane (bisphenol A) plays a major role. During the reaction, bisphenol A (diane) is dissolved in epichlorohydrin and condensed at 80-100 ° C in the presence of aqueous sodium hydroxide solution. To improve the solubility of each reaction component, ketones or secondary alcohols are added to the reaction medium. The structure of their epoxy resins thus obtained was dr. Lajos Kovács Lacquer and Paint Pocket Book (Technical Publisher, Budapest, 1972) on page 254. The numerical value of n of the repeating groups of the epoxy resin chain formed is mainly dependent on the molar ratio of the reaction mixture to di-epichlorohydrin and di-alkali. With a high excess of epichlorohydrin (e. G. 9-10 moles of epichlorohydrin per mole of diol), highly reactive low molecular weight epoxy resins can be prepared at room temperature. If the excess epichlorohydrin is reduced by adding 2-4 moles epichlorohydrin to 1 mole of di, the resulting epoxy resins will have an increased molecular weight (800-4000), less reactivity and a solid state at ambient temperature.

In addition to the already mentioned mole ratio of dianeo-epichlorohydrin in the production of epoxy resin,

The alkalinity of the 180,488 reaction mixture, that is, the mole ratio of diane to alkali, also plays an important role.

The use of excess epichlorohydrin increases the cost of production greatly, since the proliferation of epichlorohydrin in the reaction medium in the alkaline medium cannot be eliminated. A further problem is that the reaction of the diyano-epichlorohydrin produces a greater amount of sodium chloride, which can be further removed by washing the crude resin or its solution with water to remove the traces of alkali.

The preparation of liquid epoxy resins is described in Hungarian Patent No. 157,237, which utilizes phenol-formaldehyde precondensate instead of or in addition to the slide. This made it possible to use a much cheaper phenolic formaldehyde feedstock than the slide. The relative disadvantage of the epoxy resins made in this way is that they can only be crosslinked with expensive crosslinking agents.

The resulting epoxy resins are cured at ambient or elevated temperatures, depending on the intended use. Crosslinking of epoxy resins that are liquid at ambient temperature at room temperature utilizes mainly aliphatic polyamines, basic polyamides, or amine adducts. Aliphatic polyamines, such as diethylene triamine, link the linear epoxy resin chain through the epoxy end groups to form a cross-linked resin having good mechanical and chemical resistance. However, the disadvantage of polyamine crosslinkers is that the reaction is carried out with strong heat generation, the resin is rapidly cured and the epoxy coating is relatively brittle, not physiologically sound.

Therefore, epoxy resins used for surface coating purposes have recently been favored by basic polyamides (such as Versamide types made from dimerized fatty acid and aliphatic polyamine) and amine adduct crosslinking agents (products consisting of epoxy resin and aliphatic polyamine). At ambient temperature, aromatic acid anhydrides (such as phthalic anhydride) or various aromatic diamines are used to cure their solid epoxy resins at elevated temperatures.

The industrial use of liquid and solid epoxy resins is extremely diverse. Liquid products can be made into solvent-free varnishes, paints, adhesives, putty or mortar, and resins solid at ambient temperature can be used to produce epoxy powder lacquers, solvent lacquers, or epoxy-fatty acid-lacquer intermediates. 55

Thus, epoxy resin-based products are used in a wide range of applications and in increasing quantities by the paint, paint, construction, engineering and electrical industries.

It is an object of the present invention to provide a process for the preparation of phenolic resin (and / or di-based epoxy resin) having improved liquid properties at ambient temperature, and to reduce the specific amount of epichlorohydrin required, thereby reducing the cost of the resin.

A further objective was to simplify technological equipment and operations, such as the abandonment of filtering equipment and film evaporators.

The developed process allows the epoxy resins to cure equally well with a variety of crosslinking agents (e.g., aliphatic and cycloaliphatic polyamines, basic polyamides), and to cure well in anhydrous and aqueous emulsion media.

The viscosity of the epoxy resin based on dian-epichlorohydrin-based epoxy resin, known from Hungarian Patent Application No. 154181, and the phenolic resin-epichlorohydrin-based epoxy resin described in Hungarian Patent Application No. 157,237, was not maintained below 25,000 cP. without growth. Suitable viscosity Check _r manufacture of epoxy resin based on 5-30% by weight, or diluent (e.g., butyl-phenyl glycidyl ether) are added to the weight of the resin to provide the desired viscosity. We have discovered that the viscosity reduction and, at the same time, the volatile matter content can be solved by refining the prior art.

Thus, the present invention relates to the preparation of epoxy resins crosslinked with liquid polyamine and fatty acid diamide having a viscosity of 5,000 to 15,000 mPas / 25 ° C, in the form of liquid phenolic resin precondensate and / or 2,2-bis-p-hydroxyphenylpropane (diane) and epichlorohydrin alkaline.

The present invention provides a process for the production of liquid epoxy resins having a viscosity of between 5000 and 15,000 mPas / 25 ° C by condensation of phenol-formaldehyde resin and / or 2,2-bis-p-hydroxyphenylpropane (diane) and epiclohydrin in alkaline media characterized by a combination of the following operations:

- condensing 2 moles of phenol and 0.6-1.2 moles of formaldehyde with alkali;

- 1.0 mole of the phenol resin obtained alone, or 0.0-1.0 mole phenol resin mixed with 0.1-1.0 mole diane or 1.0 mole diane with 2-8 mole epichlorohydrin and 1.0-1.5 mole mole sodium hydroxide in aqueous solution to 150-170 epoxy equivalent weight and viscosity of 5 · -50 mPas / 25 ° C;

Allowing the precondensate to separate from the aqueous sodium hydroxide solution;

Decanting the aqueous phase;

- condensing the resin phase to a viscosity of 100-2000 mPas / 25 ° C and 200-250 epoxy equivalent weight in an airtight space while distilling off the bulk of the excess epichlorohydrin;

Adding an aqueous solution of sodium hydroxide (0.6-1.7 mol) and terminating the condensation under aeration and at a higher temperature;

- purifying the crude epoxy resin by solvent or aqueous washing;

- the volatile matter is blown off with moist water vapor at a pressure of 0.5 to 2.0 bar and then with inert gas.

180,488

The removal of sodium chloride from the epoxy resin condensate is conveniently accomplished by adding 1-2 times the weight of the resin in an organic solvent, and washing the solvent resin one or more times with water at a ratio of 1: 1 to 1.5, and settling the aqueous phase. From the organic phase, the resin is distilled off at a gradually rising temperature of 75-125 ° C and a pressure of 0.2-0.05 bar. The inert gas used is carbon dioxide or nitrogen.

Removal of volatile matter is accomplished by maintaining the viscosity of the epoxy resin at 5,000 to 15,000 mPais / 25 ° C, well. The phenol-formaldehyde precondensate used is a liquid resin having a viscosity of 10-15 mPas / 25 ° C and is mainly composed of isomers of dihydroxydiphenylmethane (diphenylmethane, bisphenol-F). The process of the present invention provides an improved solvent free solvent and active diluent epoxy resin.

The epoxy resin of the present invention can be crosslinked in an aqueous or anhydrous medium when surface coatings can be prepared. For example, to prepare a dispersion mortar, 100 parts by weight of liquid epoxy resin are emulsified in 50 parts by weight of basic polyamide having a viscosity of 350-400 amines and having a viscosity of 10,000-25,000 cP / 25 ° C in 100 parts by weight of water. filler is added. Modified polyamines, which also exhibit excellent film-forming properties and are suitable for coating building surfaces due to their water resistance, may also be used as crosslinking agents.

The advantage of this process is that it allows the substitution of inexpensive raw materials, such as phenol and formadehyde resin, as well as reducing the specific amount required, which is almost exclusively used in expensive raw materials (such as diane and epichlorohydrin). The resulting liquid epoxy resins are equivalent or better in terms of cross-linking than the most common di-epichlorohydrin-based so-called. "Standard" resins (e.g., Epi-kote-828 from Shell, GY-250 from Ciba-Geigy AG).

The process also has the advantage that it does not require expensive chemical equipment such as a vacuum film evaporator because the low viscosity and volatile content can be achieved in a conventional vacuum distillation apparatus.

It is also an advantage that in the first step, the precondensate is prepared in an atmospheric pressure apparatus, and the precondensate is further condensed in a vacuum distiller in the second step, separated from the aqueous phase. This separates the formation of the chlorohydrinether and the glycidyl ether, which results in a reduction of the excess epichlorohydrin and a significant increase in the recoverable and reusable proportion, as well as an improvement in the main epoxy resin properties (epoxy equivalent weight, hydrolysable chlorine). The use of the two devices increases the specific capacity of epo10 x-resin production, thereby resulting in further cost reductions. The process makes it possible to remove the sodium chloride impurity from the epoxy resin condensate by simple washing with water, without the need for a filter or centrifuge.

The improvement in properties is shown in the following compilation:

quality Epoxy resin No. 154181 is a diyano-epichlorohydrin based resin 157 No. 237 phenolic resin-di-epichlorohydrin based resin resin according to the invention (Example 1) Viscosity mPas / 25 ° C 9,000-20,000 15,000-25,000 9,000-15,000 Epoxy equivalent ^ 185-195 235-250 185-195 Total chlorine content which can be removed by alkali,% by weight 0.3-0.6 1.0-1.2 0.1-0.4 Volatile content,% by weight 0.1-0.3 5-7 0.1-0.3 Pot-life (min) 35-50 25-30 35-50 Compressive strength kp / cm ² (EMI) 900-950 950-1200 950-1100 Bending strength kp / cm ² 500-550 550-650 500-550

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

Example 1

1400 kg (8 mol) of epichlorohydrin and 432 kg (1 mol) of 2,2-bis-p-hydroxyphenylpropane were added to a steam-heated and water-cooled double-walled reactor. The temperature of the reaction mixture is increased to 65-70 ° C by steam heating while the slide is dissolved. After dissolution, 350 L of 25% sodium hydroxide solution (1.6 mol) is added at a rate of 3 L / min and the temperature is adjusted to 75 or less by proper control of heating or water 65.

180-488 ° C. After the alkaline addition is complete, the reaction mixture is allowed to cool to below 30 ° C and 400 kg of water are added and stirred for 30 minutes. The reaction mixture in the reactor was allowed to stand and the precondensate was separated from the aqueous wash. The pre-condensate has a viscosity of 8 to 10 mPas / 25 ° C and is transferred to a 2000 liter double-walled vessel, which is equipped with a descending cooler, a collecting vessel, a vacuum pump and an alkali feed tank. The precondensate is distilled at 0.11-0.17 bar at 80-95 ° C for 4-5 hours until the epoxide equivalent of the precondensate is 215-235 and has a viscosity of 100-500 mPas / 25 ° C, and from 780 to 830 liters of epichlorohydrin is collected in the container. The pressure is increased to 0.24-0.30 bar and 350 liters of 25% (1.6 mol) alkaline solution are added to the reactor at a rate of 3 L / min.

The crude epoxy resin is cooled to 50 ° C, 900 L of toluene and 400 L of water are added, stirred for 10 minutes and transferred to a 3000 L stirred reactor, where 2 wash was added, stirred for 20 minutes and then allowed to settle for at least 3 hours.

After washing with water, the upper epoxy resin phase is transferred to a 3500 liter washer 2 and the resulting wash 1 is discarded. In the washing apparatus 2, 1500 liters of washing liquid 3 formed during the washing of a previous dose of epoxy resin are sucked into the washing apparatus 2 and the epoxy resin is stirred for 20 minutes. After stirring, the epoxy resin-containing phase is allowed to stand for at least 3 hours, and the aqueous phase is separated and transferred to the washing apparatus. In the latter, the resin is washed with 1500 liters of warm water and allowed to stand for 8 to 16 hours. The upper epoxy resin phase is transferred to a 1500 L vacuum distillation apparatus, the washing liquid 3 is pumped into a washing plant 2 and reused for water washing according to the principle of countercurrent washing.

From the washed epoxy resin phase, toluene and water are distilled off at a pressure of 0.01 to 0.1 bar at a suitable rate. The toluene and water are collected in the container and can be reused after separation. When the internal temperature of the epoxy resin in the reactor rises to 95-110 [deg.] C., while maintaining the air thinning, wet steam of 1-2 bars is blown into the resin phase for 15 minutes while the temperature of the resin decreases slightly. The epoxy resin base is purged with carbon dioxide gas through the steam inlet for about 15 minutes, while maintaining the temperature and the degree of air thinning. After purging with carbon dioxide, the epoxy resin was raised to 115 ° C at 0.05-0.1 bar and condensation was completed. The epoxy resin is cooled to 70 ° C with water-cooling and, if necessary, filtered after filtration into a homogenizing vessel. The main properties of the resulting 550 kg liquid epoxy resin are as follows:

Viscosity mPas 10,700

Epoxy equivalents

Total chlorine content can be removed by alkali

Volatile matter-itartalom

190

0.15% by weight

0.11% by weight

Example 2

To the 300 L reflux condenser, steam heated and water cooled double wall reactor, 188 kg (1.0 mol) of molten phenol and 80 kg of 40% formaldehyde (0.5 mol) were added. The reaction mixture was heated to 95-100 ° C with a suitable temperature increase and then concentrated at this temperature for 3 to 3.5 hours. The resulting 64 kg phenol resin having a viscosity of 10-15 mPas / 25 ° C was transferred to the 3000 liter reactor of Example 1, where 324 kg

2,2-Bis-p-hydroxyphenylpropane and 1050 kg (6.8 mol) of epichlorohydrin were added. The reaction mixture is heated to 70 ° C, whereupon the phenol resin and the diane are dissolved. The preparation of the epoxy resin is started by the addition of 30 liters of 25% sodium hydroxide solution and the mixture becomes milky. After keeping the temperature constant, an additional 182 liters of 25% sodium hydroxide (1.5 moles total) are added at a rate of 2 liters / minute while maintaining the temperature at 75 ° C or less. The pre-condensed phase was sedimented as in Example 1 and separated from the aqueous phase.

Processing of the epoxy resin was carried out as in Example 1 by transferring the precondenser to a 2000 L vacuum distillation apparatus and distilling off excess epichlorohydrin. 215 epoxy equivalents of a resin phase having a viscosity of 217 mPas / 25 ° C are formed to which 212 liters of sodium 40 hydroxide solution at 25 ° C is added at a rate of 2 liters per minute at the temperature and pressure described in Example 1.

The crude epoxy resin was salted 45 times in three washers with three countercurrent aqueous washes as in Example 1. The washed epoxy resin phase is also freed from the solvent and water in the 1500 L vacuum distillation apparatus by water vapor purge and carbon dioxide as in Example 1. The main properties of the 520 kg liquid epoxy resin thus poured are as follows:

Viscosity mPas / 25 ° C 6,500

Epoxy equivalent 196

Alkaline cleavable total chlorine content 0.12% by weight

Volatile content 5.7% by weight

The epoxy resins prepared according to Examples 1 and 2 are crosslinkable with basic glasses or modified polyamine and have excellent film-forming properties. The basic glasses used are Versamid-140, viscosity 10,000-25,000 mPas at 25 ° C, amine value 350-400, manufactured by Cnay Valley Produots Ltd. Trade name of the modified polyamine is Aratóit-HY2964, manufactured by Ciba-Geigy. Crosslinked epoxy

The compressive strength of 180,188 resins based on 33% by weight of crosslinking agent is as follows:

Versamid - 140 1050 kp / cm ²

Harvesters — HY2964 1100 kp / cm ²

Water resistance (after 2 weeks of water soaking) no change

The liquid epoxy resin of Example 2 is formulated as an aqueous emulsion or dispersion suitable for coating wet or bonded architectural surfaces (e.g. concrete, plaster). The dispersion containing the epoxy resin binder is prepared according to the following composition:

parts by weight of the epoxy resin of Example 2

150 to 200 parts by weight of silica sand with a particle size not exceeding 0.2 mm

150 to 200 parts by weight of quartz flour

150 parts by weight of base polyamide emulsion

Mixing each component gives a dense, water-dilutable dispersion. The dispersion can be applied on a concrete surface in a thickness of 0.5 to 2 mm, the coating hardens within 24 hours, is highly mechanical, hard and impermeable to water.

Example 3

The 3000 liters reactor of Example 1 was charged with 360 kg of the liquid phenol resin prepared in Example 2, followed by 304 kg of diene and 986 kg of epichlorohydrin. (Molar ratio: 0.5: 0.5: 4.0.)

The reaction mixture is heated to 70 ° C while the slide and phenol resin are dissolved. Preparation of the epoxy resin was started with 30 liters of 25% NaOH and then when the temperature was constant, 2.8 liters / min. A further 560 L of alkaline solution (w / w / mol molar ratio 1: 1.7) is added at a rate while allowing the temperature to rise to 75 ° C.

The viscosity of the pre-condensed phase is max. 50 mPas / 25 ° C, epoxy equivalent 150-170.

The pre-condensed phase was sedimented as in Example 1 and separated from the aqueous phase and transferred to a 2000 L vacuum distillate, where the excess epichlorohydrin is 210-215 epoxy equivalents, 5-6% hydrolysable chlorine and 500-1000 mPa.s / 25 Distillation to a viscosity of 0 ° C. An additional 284 L of 21% aqueous alkaline solution was added to the resin phase at the temperature and pressure of Example 1 at a rate of 2.8 L / min. (The molar ratio of diol to alkali is 1: 0.7.)

Hereinafter, the same procedure as in Example 1 was followed to obtain 710 kg of liquid epoxy resin having the following main characteristics:

Viscosity 9700 mPas / 25 ° C

Epoxy equivalent 206

Chlorine hydrolysable with alkali 0.1%

Volatile content 1.1%

Example 4

According to Example 1, 540 kg of the phenolic resin of Example 2 were injected into a 3000 liter reactor. Then 521 kg of 25% sodium hydroxide solution are added.

The temperature of the reaction mixture is the effect of the alkali

Rises from 40 ° C to 50 ° C, turning on water cooling to cool the reactor contents to 20 ° C to 25 ° C.

The reaction mixture was then treated with 740 kg of epichlorohydrin. (Diol: epichlorohydrin: alkali molar ratio: 1: 4: 1.6.) This causes the formation of the epoxy resin, which is accompanied by an increase in temperature to 60-70 ° C. The reaction was then continued at 75-80 ° C for 1 hour. The precondensed phase thus obtained was sedimented as in Example 1 and separated from the aqueous phase. The epoxy resin was worked up in the same manner as in Example 1 by transferring the precondensate to a 2000 L vacuum distillation apparatus and distilling off excess epichlorohydrin. To the residual resin was added 192 kg of alkaline solution at a rate of 2 liters per minute at the temperature and pressure of Example 1. (Mole ratio of diol to alkali: 1: 0.6.)

To the crude epoxy resin thus obtained was added a mixture of 400 liters of toluene and 200 liters of n-butanol and 200 liters of water, stirred for 10 minutes, and then pumped into washing machine 1.

Hereinafter, the crude resin was washed as described in Example 1 and finally removed by vacuum distillation to remove water and solvent.

Main characteristics of the epoxy resin formed:

Viscosity 9300 mPas / 25 ° C

Epoxy equivalent 203

Alkaline cleavable chlorine content 0.2% by weight

Volatile content 5.8% by weight

Claims (3)

A process for the preparation of epoxy resins having a viscosity of 5,000 to 15,000 mPas / 25 ° C at ambient temperature by condensing phenol resin and / or 2,2-bis-p-hydroxyphenylpropane and epichlorohydrin in an alkaline medium, characterized in that 2 mol. phenol and 0.6 to 1.2 moles of formaldehyde are basically condensed to form 1.0 mole of the phenol resin alone, or 0.1 to 1.0 mole phenol resin mixed with 0.1 to 1.0 mole of diene, or 1.0 mole of di -8 moles epichlorohydrin and 1.0-1.5 moles aqueous sodium hydroxide solution to 150-170 epoxy equivalents by weight and a viscosity of 5-50 mPas / 25 "C, the precondensate is separated with the aqueous sodium chloride solution formed, and the aqueous phase is then separated decant, the resinous phase is further condensed to a bulk of epichlorohydrin to a viscosity of 100-2000 mPas.'25 ° C and a viscosity of 200-250 epoxy equivalents. condensation is completed, the crude epoxy resin obtained is purified by solvent and / or aqueous washing, and finally the volatile material is conveniently treated with water vapor and inert gas at a pressure of 0.5 to 2 bar. blown off. 2. The process according to claim 1, wherein the crude resin is -511 It is taken up in 1-2 times the weight of 180,488 tat in organic solvent and the resin solution is washed with water 1 to 3 times by weight in a 1: 1-1.5 weight ratio and the aqueous phase is separated by settling. 3. The process of claim 1, wherein the crude epoxy resin is purified by washing with water and then removing the volatiles at temperatures between 75 ° C and 125 ° C and pressures between 0.2 and 0.005 bar.