DE2534849B2 - Aqueous RESOL DISPERSION - Google Patents

Description

The present invention relates to aqueous phenol resol dispersions containing Ghatti gum (»gum ghatti «) and a thickener.

In US-PS 3823 103 aqueous phenol resol dispersions are described, which are produced in the presence of gum arabic and at least one other gum. These dispersions are characterized by excellent stability and the ability to be infinitely dilutable with water be. In a preferred form they can contain particles with an average diameter between about 5-20 microns, with virtually all resin particles being less than 40 microns in diameter.

In "Industrial Gums - Polysaccharides and Their Derivatives" by Whistler and BeMiller (Academic Press, New York and London, 1973) it is stated on page 268 that Ghatti Gum is a better one Is emulsifier as gum arabic. On page 352 of this book it is stated that psyllium seed gum suggested as a substitute for gum arabic as an emulsifier, and on page 357 one can find the Indication that flaxseed gum is similarly recommended. Carboxymethyl cellulose, which is found in many Respect as a synthetic gum is often used as a substitute for gum arabic suggested in emulsions.

Attempts have been made by the inventors to produce aqueous resole dispersions by analogous processes

produce according to the invention, each Psyllium seed gum, flax seed gum and carboxymethyl cellulose as interfacial agents was used. In either case, the results were unsatisfactory. No phase inversion was obtained,

therefore no resin-in-water dispersion was formed.

The above shows that the suitability and effectiveness of a rubber in manufacture of aqueous resole dispersions not from its

known behavior can be predicted in the end uses for which the rubbers were previously used became.

The present invention creates an aqueous resole dispersion containing dispersed particles of a

^ao nes phenolic resole in water and a thickening agent which is characterized in that it additionally contains Ghatti gum and that practically all particles have a diameter below about 25 microns. Furthermore, the present invention creates

^a 5 dung a process for the preparation of such dispersions, which is characterized in that a phenol is reacted with an aldehyde in the presence of a basic catalyst for a sufficient duration and at a sufficient temperature to form a phenolic resole, this phenolic resole in situ in one dispersed aqueous medium containing Ghatti gum and a thickener, and optionally heated the reaction mixture for a sufficient time to increase the weight average molecular weight of the resol to a value between about 400-3000 at elevated temperature, with the proviso that the pH of the reaction mixture before heating is below about 9.

Formaldehyde or a material can be used as aldehydes to form the phenolic resole which feeds formaldehyde or its equivalent, such as paraformaldehyde, to the reaction mixture or hexamethylenetetramine, acetyldehyde, furfural, acrolein or other aldehydes, with formaldehyde, particularly preferred as the aqueous solution known as "formalin".

The phenols used to prepare the resols used according to the invention include unsubstituted ones Phenol, d. H. Monohydroxybenzene, and various substituted mono- and polyhydric phenols, such as o-, m- and p-cresol, ethylphenol, propylphenol, p-tert-butylphenol and other butylphenols, Amylphenol, octylphenol, cyclohexylphenol, nonylphenol, dodecylphenol, and other alkylphenols; p-phenylphenol; styrene treated phenol; halogenated Phenols such as chloro- and bromophenol; Hydroquinone; and bisphenols such as 2,2-bis (4-hydroxyphenyl) propane (Bisphenol-A) and bis (4-hydroxyphenyl) methane.

The monohydric phenols used are usually di- or trifunctional; d. H. 2 or 3 of the o- and p positions to the phenolic hydroxyl group are normally unsubstituted. Are bisphenols usually tetrafunctional, although up to 2 of the reactive o-positions of the phenolic hydroxyl group can be substituted.

Usually about 0.5-4 moles is preferred

about 1.-3 moles, aldehyde used per mole of phenol, known to be more aldehyde used when that Phenol is a bisphenol as if a monohydric phenol is used.

An alkaline catalyst is used in the manufacture of a phenolic resole. Special catalysts are z. B. the alkali and alkaline earth metal hydroxides, oxides or carbonates, such as sodium, potassium and barium hydroxide, calcium oxide, sodium carbonate, etc .; ammonium-containing compounds, such as Ammonia, hexamethylenetetramine and quaternary ammonium hydroxides; and amines, such as ethylenediamine, Trimethylamine, dimethylamine and N, N-dimethylethanolamine.

The catalyst is used in catalytically active proportions, e.g. B. from about 0.007-0.4, preferably about 0.01-0.1 equivalent of catalyst per mole of phenol used.

The erlfindungsgemäßen aqueous dispersions are prepared by a process which DA is ^ao characterized by reacting a phenol with an aldehyde in the presence of an alkaline reacting catalyst to form a substantially water-insoluble phenolic resole and this resole in the presence of ghatti gum and a Dickungsmit- ^a 5 means dispersed in an aqueous medium.

This procedure is expediently carried out as follows:

Phenol, aldehyde and catalyst were in a reaction vessel with the usual devices for 3 <> Stirring, heat transfer, reflux and control introduced. An inert one is expedient Also used diluent, which acts as a reaction medium. Water is preferred and usually added with the aldehyde, since in most cases the aldehyde used is aqueous formaldehyde will. The condensation reaction between the phenol and aldehyde is usually initiated by external heating the reaction mixture introduced until the condensation begins. After that causes the exothermic Nature of the reaction, its persistence. The temperature control is usually through reflux achieved at a regulated pressure with external heating or cooling applied if necessary will. The condensation continues until at least one low viscosity resol is formed. the Viscosity should be low enough so that the resole increases with the shear force available in the reaction vessel a resin with a small particle size can be crushed.

At this point, additional water can be added along with the Ghatti gum and thickener Reaction mixture are added. To improve the stability of the resole, it is often useful to use the neutralize alkaline catalyst before further processing. The pH of the reaction mixture should normally be about 9 or less, preferably about 3-7.5, and especially between about 4.5-6.5 after the initial phenol / aldehyde condensation is complete; H. possibly after neutralization. The particular pH chosen depends in part on the type of phenol and the end use intended for the dispersion away.

An important feature of the present invention is that the resole in the presence of Ghatti gum and thickener in situ in water ilknp.rpier »will. That is, the resole is in water dispersed before it is isolated from the reaction mixture. Is the resol from the reaction mixture isolated and then later redispersed in water, one cannot even come close to such a fine particle size the dispersion is still so stable.

The Ghatti gum and / or the thickener can be in the reaction mixture from the beginning of the Phenol / aldehyde condensation reaction be present. However, it is preferred to condense up to form a low viscosity resin and then Ghatti gum, thickener and add more water if necessary. (At this point the resin can still be at least partially be soluble in water. The resol can only after neutralization and / or thickening [»bodying«) become practically insoluble in water.) Sufficient water must be present in the dispersion so that phase inversion can take place, d. H. to achieve a resin-in-water dispersion (where the water is the continuous phase). Typical maximum resol solids concentrations are between about 40-50% by weight, determined by measuring the weight loss of a 1.5 g sample after 3 hours in an oven at 135 ° C. If the phenol is an unsubstituted phenol, then the maximum permissible is Solids content tends to be in the lower part of this range. If the phenol is bisphenol-A, then that is the maximum permissible solids content rather in the upper part of the range, and if the phenol is an alkylphenol, the maximum permissible solids content is usually in the middle of the range. Of course, more can be done Water can be used. For various economic reasons (e.g. shipping costs However, the water content is preferably kept as low as possible.

As mentioned above, the best time practice is the Adding Ghatti gum, thickener and (if necessary) additional water to the reaction mixture not later than after the formation of the low viscosity resin. (The condensation takes place at elevated Temperatures, e.g. B. 75-105 ° C, and at these temperatures the resol is liquid.) Possibly one or two tries are necessary to determine the best time to add the Ghatti gum, Determine thickener and water for the particular resols. Specialists in phenolic resin chemistry, however, those who have been producing resoles on a large scale for more than 40 years can post this point Determine the examination of the documents relating to the deregistration.

The dispersion of the resole in water is achieved by touching the reaction mixture, which Contains virtually water-insoluble resole, water, ghatti gum and thickeners, applies shear force. Stirring the reaction mixture is the most convenient way to create the necessary Shear force.

The resol must be practically insoluble in water. Although this will vary somewhat depending on the exact nature of the resole, in order for the resole to normally be water insoluble, the resole must have a weight average molecular weight of at least about 401). The resols according to the invention can have weight average molecular weights of up to about 3000 or more: the weight average molecular weight can be determined according to known methods; see τ. B. Moore, "J. Poly. Be., Part A «, 2, 835

(1964).

In order to achieve the degree of "thickening" desired for the intended end use in the resole, ie an increase in the average molecular weight to a value between about 400 and 3000, it is often expedient to use the resole after adding Ghatti gum, thickener and water and if necessary, after neutralization of the catalyst, to lower it to an elevated temperature for a controlled period of time. This treatment is often referred to as "bodying" the resin. It is usually carried out at a temperature of about 80-95 ° C for a period of about 5 minutes to 2 hours or more. Is the resole is a thermosetting material, then the thickening can be followed by the resole ^iS periodically to its gel time at 150 ° C (z. B. every 15-20 minutes) tests, until the desired degree of thickening achieved. The Pheiiolresolchemiker are familiar with this concept and know which thickening is for a particular end neces- ^ao agile.

Ghatti gum and a thickener are used to prepare the dispersions of the invention used. Ghatti gum is a naturally occurring plant exudate made from the stems of Anogeissue latifolia, a plant common in India and Ceylon. It is a polysaccharide, D-galactose, Contains mannose, glucuronic acid and rhamnose units. The Ghatti Gum will be sufficient Amount used to form and stabilize a dispersion of resol particles in water. Sufficient Amounts of Ghatti gum are usually between about 0.5-5, preferably about 1-3 parts by weight per 100 parts by weight of the phenol added to the reaction mixture.

The thickening agent used can consist of one or more of the following materials: Gums such as guar gum, carrageenin gum, algingum, locust bean gum; and water soluble Polymers, such as ethylene / maleic acid copolymers, Ionomers, polyacrylamide, methyl vinyl ether-maleic anhydride copolymer; and all other water-soluble polymeric materials that increase the viscosity of water and with the other components of the dispersion are compatible.

The thickener is in sufficient amount to increase the viscosity of the dispersion to at least about 500 centipoises used at 23 ° C. Usually there is an effective amount of thickener between about 0.1-1, preferably about 0.25-0.8 parts by weight per 100 parts by weight of the zur Reaction mixture given phenol.

The individual phenolic resole particles obtained in the aqueous dispersions of the invention can be smaller and more uniform in size than those of phenolic, with gum arabic dispersions formed as interfacial agents. So z. B. those produced according to the invention Dispersions have particles which practically all have a diameter below 5, preferably under 3 microns. Their average diameter is between about 1-3 microns. While the The invention also encompasses dispersions having larger particles (e.g., having an average particle diameter below about 12 microns, with virtually all of the particles having a diameter below about 25 microns For many end uses, it is better if the particle size is smaller and more uniform is. These end uses include such as adhesive and coating, with phenolic Dispersion used in conjunction with an addition polymer latex such as an acrylic latex will.

The dispersions produced so far with gum arabic as an interfacial agent with the smallest and most uniform particle sizes vary in particle diameter from about 5-10 microns.

The following examples illustrate the present invention without restricting it.

example 1

The following materials were placed in a 5-1 round bottom flask equipped with a reflux condenser, stirrer, thermometer and heating mantle:
Phenol 1200 g

40% aqueous formaldehyde 1668 g

25% aqueous sodium hydroxide 100 g

This mixture was heated to 70 ° C. with stirring, whereupon the heating mantle was removed and the reaction mixture was removed rise to atmospheric reflux temperature due to their exothermic heat of reaction which was at about 102 ° C. The initial violent reaction was increased by cooling as needed weakened with a cold water bath to avoid excessive flooding of the radiator.

This mixture was refluxed for about 30 minutes. After that became the following Materials added in the order listed: water 720 g

Ghatti gum 24 g

Guar gum 6 g

20% strength aqueous sulfuric acid 138 g

After mixing for 5 minutes the pH was 5.2.

The contents of the flask were then heated to 80 ° C. and held at about 80 ° C. for 40 minutes. After these 40 minutes the contents of the flask were cooled to below 30 ° C and dispensed into a suitable container as a dispersion of phenolic resole in water with the following properties:
Solid content 41.2%

pH 5.5

Gelation on hot plate (150 ° C) 110 seconds

Brookfield viscosity 1050 centipoises

25 ° C

Particle size
(by microscopic examination

1 to 3 microns

After 16 weeks at room temperature, there was no noticeable settling of the resin particles. The dispersion could be diluted infinitely with water.

Control attempt 1

This experiment shows the effect of ghatti gum alone, without a thickener.

Apparatus and procedure were as in Example 1, but without the addition of the guar gum. It the following materials were added to the 5 L flask:

Phenol 1200 g

40% aqueous formaldehyde 1668 g

25% aqueous sodium hydroxide 100 g

This mixture was heated to 71 ° C., the heating jacket was removed and the temperature through the

xothcrmc heat of reaction allowed to rise. the Mixing was about 30 minutes at atmospheric Reacting reflux. After 30 minutes the following materials were mentioned in the above Order added:

Water 72Og

Ghatti gum 24 g

2% strength aqueous sulfuric acid 135 g

The pH of the resulting mixture was

V by adding 10 g of 25% strength aqueous sodium hydroxide set to 5.6.

The contents of the flask were then heated to about 80 ° C. and held at this temperature for about 60 minutes and cooled below 30 ° C. The resulting phenolic resole dispersion had particles of about 2-30 Micron. This was in marked contrast to the particle size of 1-3 microns in the product of Example 1. Due to the larger particles and lower viscosity of the product from this experiment showed a rapid settling.

Example 2
Production of a phenolic dispersion

(derived from bisphenol-A)
using Ghatti rubber with

Guar gum

1200 g of bisphenol-A, 924 g of 40% aqueous formaldehyde and 14.4 g of 25% aqueous sodium hydroxide were placed in a 5-liter round-bottomed flask equipped with a reflux condenser, stirrer, thermometer and heater. The mixture was heated to about 90 ° C, the Hcizmantcl removed and the mixture allowed to reflux under vacuum at 95 ° C, the pressure of the reaction mixture was 12.5-15 cm Hg below atmospheric pressure. The mixture was then refluxed for 60 minutes at 95 ° C., if necessary with additional heating. Then 864 g of water, 24 g of Ghatti gum and 3.6 g of guar gum were added to the contents of the flask with vigorous stirring % aqueous phosphoric acid was added to the flask and the pH was adjusted to 6.2, the contents of the flask were then brought to about 90 ° C. and held at this temperature for 90 minutes, after which they were cooled to below 50 ° C. and used as resin-in Removed water dispersion with a solids content of 48% by weight and a gelation rate of 155 seconds at 150 ° C. The viscosity of the dispersion (Drookficld spindle No. 2 at 30 rev / min) was 1050 cps, and the size was practical between 2-5 microns. This material did not settle down for 13 weeks of lounging standing.

Control attempt 2 Preparation of a chemical dispersion

(derived from bisphenol-A) without the use of a thickener

In Example 2, a phenolic dispersion was prepared, but no guar gum was added to the reduction mixture. The viscosity of this dispersion (Brookfield spindle No. 2 at 30 rev / min) was 150 eps, and the Hurztellchcngrttßc was between 2-25 microns with an average size of about 10 microns. About 25% of this compound settled after standing for 3 weeks, Example 3
Production of a phenolic dispersion

(derived from bisphenol-A),
where instead of guar gum carob tree gum was used

In a 5-liter round-bottom flask fitted with a reflux condenser, stirrer, thermometer and heating jacket 1000 g bisphenol-A, 770 g aqueous, 40% strength

ίο formaldehyde and 12.2 g aqueous 25% sodium hydroxide given. The mixture was heated to 90 ° C., the heating jacket removed and the mixture under an abs. Reflux pressures of 12.5-15 cm Hg under atmospheric pressure at 95 ° C

> 5 was left. The reflux was at 60 minutes Maintained 95 ° C with additional heat added as needed. After 60 minutes were 770 g water, 20 g ghatti gum and 6.5 g carob gum (0.09 mm) under vigorous

»O Stirring added to the contents of the flask. 8.0 grams of 42% aqueous phosphoric acid was then added to the flask added and the pH adjusted to 6.5. The contents of the flask were brought to about 90 ° C and 120 Maintained at this temperature for minutes. Thereafter

It was cooled to below 50 ° C and used as a resin-in-water dispersion With a solids content of 48% by weight and a cleaning rate on a hot 150 ° C plate removed by 171 seconds. The viscosity of the dispersion was 2000 cps. (Brookfield Spindle no. 2 at 30 rev / min); the particle size of the dispersed resin was practically between 2-5 micron diameter. This material did not settle significantly after 8 weeks of exposure.

Example 4
Production of a phenolic dispersion

(derived from bisphenol-A),

with the guar gum replaced with sodium alginate

became

The formulation and procedure were as in Example 3, except that 4.5 g of sodium alginate was the 6.5 g Replace carob tree gum. The viscosity of the dispersion (Brookficld Spindle No. 2 at 30 Rev / min) was 770 cps; the particle size of the resin was essentially between 2-5 microns Diameter, this material persisted after 3 weeks Don't stand out at all. Withdrawal after 8 weeks was less than 5%.

_like example 5

Production of a phenolic dispersion

(derived from bisphonol-A),

whereby ethylene / mulcinol hydride copolymers

runs the guar gum replaced

The procedure and formulation were as in Example 3, except that 7.0 g of an ethylenic / Muleinstiureunhydrld-Mlschpolymcrisutcs replaced the 6.5 g of Johnnlsbrolbnumgutnmi and no phosphoric acid use to neutralize the reduction mixture

was det. The viscosity of the dispersion was

16400, the short parts had a diameter practically between 2-5 microns. This material continued

I don't feel like standing up.

Presumably in some fills a nledrl

6j lower concentration in the ethylene / mineral oil hydride mixture polymer to achieve a dispersion with lower viscosity, the easier httndhubbur should be two-way.

Example 6 Preparation of a phenolic dispersion

(derived from alkylphenol) using Ghatti gum and

Guar gum

In a 5-1 round bottom flask equipped with a reflux condenser, stirrer, thermometer and heating jacket 1200 g of p-tert-butylphenol, 1200 g of aqueous, 40% strength formalin and 36 g of aqueous, 25% strength sodium hydroxide given. The mixture was heated to 73 ° C, the heating mantle removed, and the mixture Allowed to reach 80 ° C, whereupon it was held at this temperature for 2 hours. After that she became heated to atmospheric reflux and held for 60 minutes. Then 780 g Water, 24 g ghatti gum and 4.8 g guar gum were added to the contents of the flask with vigorous stirring. 10.8 g of aqueous, 42% strength phosphoric acid were added and the pH adjusted to 6.7. The contents of the flask were then brought to 95 ° C. and 2 Held at this temperature for hours. It was then cooled to below 50 ° C and used as Resin-in-water dispersion with a viscosity (Brookfield spindle No. 2 at 30 rpm) of 890 cps and resin particle size practically between 5-18 microns in diameter removed. This material did not settle after standing for 12 weeks.

In Example 6, the phenol / formaldehyde condensation reaction took place at a lower temperature than the other examples from the following Establish:

The condensation between the tert-butylphenol and formaldehyde is relatively slow due to the low solubility of tert-butylphenol in water. The resol products containing 3 or more phenolic nuclei from this reaction contain hyperacid phenolic hydroxyl groups; therefore these products tend to lower the pH of the reaction mixture more than "usual" resols. For these two reasons, more alkali is required for catalysis. The higher alkali concentration, however, tends to increase the occurrence of side reflections, in particular the Cannizzaro reaction. The reaction speed of the desired condensation is, however, significantly less reduced than that of the Cannizzaro reaction by lowering the temperature. Therefore, a lower reaction temperature is used , which - although it requires a slower reaction time - reduces the occurrence of secondary ions.

Example 7 Conversion of a phonolic dispersion

(derived from phenol-alkylphenol) using Ghatti undduargumml. W) O g phenol, W) O g p-nonylphenol, <) t ? i g retardant, added 40% formaldehyde and 24 g Lger wltlklges, 25% sodium hydroxide; the mixture was heated to 85 ° C., the helm was removed and the mixture was allowed to reach atmospheric reflux due to its exothermic heat of reaction g of Cimir gum were added to the inside of the flask. Id g llUl of 42% phosphoric acid was then added to the flask and the pH of the mixture was adjusted to 6.65. The contents of the flask were then brought to 95 ° C. and held at this temperature for 1 hour It was then cooled to a temperature below 50 ° C and removed as a resin-in-water dispersion with a viscosity (Brookfield spindle No. 2 at 30 rpm) of 2360 cps and a resin particle size essentially between 2-6 microns. The dispersion separated afterwards

ίο 12 weeks of standing not.

Control attempt 3

This experiment shows the use of Ghatti gum and a sodium salt, polymerized sub-

substituted benzene alkyl sulfonic acids in the production of a modified phenolic resole in dispersion form as specified in the brochure from Hercules "Vinsol Resin as Modifier of Phenolic Resins", copyright 1955, page 23.

In a 5-1 round bottom flask equipped with a reflux condenser, stirrer, thermometer and heating mantle given the following materials: phenol 1005 g

Phenolic Resin Modifier 495 g

40% formaldehyde 884 g

Water 67.5 g

Paraformaldehyde 350 g

The mixture was heated to atmospheric reflux with constant stirring and until dissolved of the paraformaldehyde kept at this temperature. After the contents of the flask have cooled to 26 ° C the following materials were added: ammonium hydroxide (29.6%) 318 g

Ghatti gum 27 g

Sodium salt polymerized substituted

Benzene alkyl sulfonic acids 4.5 g

The resulting mixture was heated to 75 ° C,

the heating jacket removed and the temperature through

let the exothermic heat of reaction rise.

After reaching a temperature of 98 ° C additional heat applied to bring the mixture to atmospheric reflux, the reaction at atmospheric reflux was continued for a total of 3 hours, after which the mixture was allowed to drop below 40 ° C

has cooled down,

The product obtained was an aqueous dispersion of a phenolic resin having a particle size range between about 2-160 microns. After two days at room temperature, the dis Pergated resin phase settled and could only be dispersed again by vigorous stirring.

Control attempt 4

As part of this experiment, the "Vinsol" from control experiment 3 was omitted.

Unrelated Use of Device and Expiration In control experiment 1, the following materials were placed in a 5 liter flask:

flo phenol | () U5

40% formaldehyde HM

Water (»7.5

Paraforinaldchyd. 107.5

The above mixture was used to dissolve the Pam

"L's ormaldehyds on ulimviphllrlsclicn reflux HEATER After cooling to .Vl" C were added; Ammonlumhydtiixid (2 ^l Ui%) 318

ühuttl thin »! 27

Sodium salt polymerized substituted
Benzene alkyl sulfonic acids 4.5 g

The temperature of the mixture rose due to the exothermic heat of reaction. As the atmospheric Reflux began, the reaction was slowed down by cooling with a cold water bath as needed, to regulate foaming and prevent the cooler from flooding. After 3 hours at atmospheric reflux the contents of the flask were cooled to below 40 ° C.

Microscopic examination of the phenolic dispersion obtained showed a wide range from particle sizes up to 160-200 microns in diameter, with a large percentage of the particles being 50 Micron or larger.

The dispersions according to the invention are stable over long periods. In most cases, this does not occur noticeable settling of the resol particles after standing for 4 weeks and, in many cases, even longer

ίο duration on, as the above examples show.

Claims (4)

Patent claims: 1. Aqueous resole dispersion containing dispersed particles of a phenolic resole in water and a thickener, characterized in that it additionally contains ühatti gum and that practically all of the particles are one Have a diameter of less than 25 microns. 2. Dispersion according to claim 1, characterized in that practically all particles have one Have a diameter of less than 5 microns. 3. Dispersion according to claim 1 and 2, characterized in that the Ghatti rubber in one Amount of 0.5-5 parts by weight and the thickening agent in an amount of 0.1-1 part by weight per 100 parts by weight of the phenol used to prepare the resole is used. 4. Process for the preparation of aqueous resole dispersions according to Claims 1 to 3, characterized in that characterized in that one a phenol with an aldehyde in the presence of a basic catalyst for a sufficient time and at a sufficient temperature for a phenolic to form Resole converts this phenolic resole in situ in an aqueous, Ghatti gum and dispersed a medium containing a thickener and optionally the reaction mixture for a period sufficient to increase the weight Average molecular weight of the resol heated to a value between 400-3000 at an elevated temperature, with the Condition that the pH of the reaction mixture is below 9 before heating.