CA1080871B - Calcia catalyzed resins - Google Patents

Abstract

A B S T R A C T

A method of making a calcium catalyzed thermosetting phenol formaldehyde resin suitable for modification for use in binder formulations, foams, and other uses. Aqueous binder formulations are prepared from such binder resins, particularly for use in bonding glass fiber articles. The method comprises the step of methylolating phenol with formaldehyde under alkaline conditions, in the presence of calcium oxide (calcia), or calcium hydroxide, and water as a solvent. The formaldehyde is introduced in high ratios of 2.8 to 4.5 moles per mole of phenol. A high level of calcium hydroxide is present, in an amount of 3 to 5.5%
calcium based on weight of phenol. The methylolation reaction is terminated while the condensation reaction product is still water soluble. The condensation product may be reacted with a monomer or an amine type resin.

Description

DISCLOSURE:
This invention relates to the 2roduction o~ thermosetting phenol formaldehyde resins.
A great deal of prior worlc has been done on the phenol-formaldehyde resins system. These :resins are valuable for use in preparing various thermosetting materials. It is also commonly known to react phenol and formaldehyde in the presence of another monomer to yield a condensation product.
In the present invention, the phenol is methylolated in the absence of other monomers using calcium oxide (calcia), or calcium hydroxide as a catalyst. The use of calcium type catalysts is known in the art. The known prior art does not disclose the present invention, nor are they capable of making full water-soluble products having the desirable characteristics achieved by the practice of the present invention.
In the commercial manufacture of phenol formaldehyde resins, it is economically desirable to achieve as high a ratio of formaldehyde to phenol as is practical, in order to permit the subsequent combination with higher amounts of low cost monomers.
Such high mole ratio of formaldehyde to phenol in binder resins also appears to increase the resinification efficiency, and leads to a better bond with any substrate to which the material is to be applied, when combined with additional monomers. In particular the presence of unsubstituted (free) phenol in the product is found to be detrimental to the resin. The phenol will have a tendency to distill off in the curing process and this constitutes a potent air pollutant.
Structurally, the upper limit for formaldehyde addition is about 3 moles of formaldehyde per mole of phenol. In accordance with the present invention, a high ratio of formaldehyde is pro-; vided together with a very high ratio of calcium catalyst. In the calcia-cataLyzed system, the high catalyst percentage directs the - 1 - : ' ' ~;

reaction toward~ a minimum of unreacted phenol, while slmulta-neously a minimum of water insoluble ph0nyls are formed. The present invention provides a means of ~orming such binders in an essentially one-step process, by the use of a catalyst which achieves the reaction more easily.
The present invention provides a product which has a low content of water insoluble materials, free phenol, monomethylol, and the like, and avoids the necessity for extracting such mat-erials. The prior art requires various types of extraction steps for the obtaining of a suitable resin.
The present invention therefore provides a method of making a calcium catalyzed thermosetting resin comprising the step of methylolating a phenol with formaldehyde, under alkaline conditions, in the presence of calcium hydroxide, and water as a solvent. The methylolation reaction is terminated by cooling while the condensation reaction product is still water soluble.
The formaldehyde is introduced in an amount of 2.8 to 4.5 moles per mole of phenol. The calcium hydroxide is present in an amount of 3 to 5.5% calcium based on the weight of phenol. The pH during 2Q the cooking reactions will be moderately alkaline in the range of 8 to 9.5t and ~iLl preferably be in the range of 8.3 to 9.5, and most preferably 8.5 to 9.5.
The formaldehyde may preferably be introduced in an amount of 2.8 to 4.5 moles per mole of phenol, preferably 3 to 4.5;
more pre~erably 3.5 to 4; and most preferably 3.5; 3.6; 3.7 or 3.8 --moles per mole of phenol. The phenol most preferably should be U. S. P. grade. The calcium hydroxide may preferably be present in an amount of 4.5 to 5% calcium, based on the weight of phenol.
The reaction may be carried out at any suitable tem-30 perature, preferably no higher than about 155F., and preferablyfor a period of 3 to 10 hours.

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The minimum ~e~ction tlme is not sharpl~ de~ined and is contingent upon the effectivenass of the heat exchange mechanism.
It will normally be at least three hours in conventional batch apparatus equipped with a high speed stirrer. However, it is possible to achieve the desired reaction in a lower time, provided that the exothermic reactton does not over heat the material.
For example, it should be possible to operate at a reaction time of 2 and 1/2 or 2 hours, or even lower, in a continuous reaction system or in a very small reactor, where the heat ma~ be dissipated iO quickly. The same effect might be achieved if very high shear apparatus is employed.
The reaction temperature should preferably be maintained no higher than 125F. for the first hour of reaction time. The reaction may be carried out in batches or may preferably be carried out in a continuous manner in apparatus suitable for the purpose.
If the reaction is carried out at atmospheric pxessure, the tem-perature will preferably be controlled by the use of heating and ~
cooling coils. The reaction may also be carried out at sub-atmos- 1~ -pheric pressure with a reflux condenser being employed to maintain 2Q the reagent concentrations. After carrying out the process the product may, if desired, be brought to a neutral or mildly alkaline pH of 7 to 7.6 by addition of an acid. Partial or complete neu-tralization of the resin tends to increase the gel time of the resin among other things. For example, the gel time by a standard method in one case went from about 300 seconds to 450 seconds and then to 600 seconds, in adding acid and bringing the pH from 8.6 through 8.2 to 7.6. Among acids which have been found suitable ;
are the following: sulfamic, phosphoric, sulfuric, acetic, maleic, and carbonic acids, and their ammonium salts. Alternatively, the 3a resin may be stored at room temperature or under refrigeration in its alkaline condition and neutralized just before use, if at all.

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:, '~' ' ' ' . ' The condensatiQn reacti~n product will normally be ~ur-ther combined with a monomer or an amine type resin or amine type copolymer resin. Accordingly, the above method may ~urther com-prise combining the condensation product with up to 82~ of a mono-mer or an amine type resin or amine type copolymer resin based on the combined solids to produce a thermosetting, low phenolic, res-inous bonding material.
The present invention further provides a water disper-sable soluble or water soluble calcium catalyzed phenol-formalde-lQ hyde condensation resin product, characterized as follows:
(i) a ratio of 2.8 to 4.5 moles of formaldehyde per mole of phenol, (ii) 3 to 5.5% of calcium based on the weight of phenol, (iii)- not over about 2% unreacted phenol by weight, (iv) between 3 to 16% unreacted formaldehyde, by weight, (v) between 2.3 to 2.7 methylol groups per phenol molecule, (vi) low content of water-insoluble higher phenyls, preferably not exceeding 1.5% of total as determined by gas chromato~raphy on the silylized resin, (vii) low content of monomethylolphenol, preferably not exceeding a maximum content of 1.5%, based upon the weight of the liquid resin.
__ The unreacted (free) phenol will be normally present between 0.10% and 2.0% by weight, which is considered to be among acceptably low levels.
The resins produced by the present invention may be practically clear. Following neutralization any insoluble neu-trazliation products are of micron to sub-mircon particle size and are essentially non-settling.

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The resin conflguration contributes to the outstanding chemical stability at room termperature of these resins. This stability which has been observed before or after neutralization of the catalyst by conventional means, is remarkable in view of the relative instability of the prlor art products, and is econo-mically attractive. Because of it, the resins produced following this invention ~lay be stored or shipped at ambient temperatures or lower, with or w-ithout having been neutralized.
The choice of calcia in high concentration as catalyst la further contributes to more economical and efficient production of a higher quality material than is achieved with the conventional catalysts such as alkali metal hydroxides, barium hydrates, etc. ~ ;
The material costs are rather considerably lower since relatively inexpensive calcium oxide (burnt lime) may be employed. The cal-cium oxide or calcium hydrate used in carrying out the present development work came from various sources, as reflected in the ';
accompanying examples. In addition to the lower raw material costs for the catalys~, the resinification efficiency is higher during the reaction, i.e. a higher proportion of the phenol and formal-2Q dehyde is converted into useful resin solids.
Further technical and economical advantages arise from ~;
the finding that resins produced by the present invention, when combined in aqueous solution with urea and the conventional binder - - ingredients, show better bonding characteristics at 60% advanced calcium catalyzed phenolic resin combined with 40% urea, than 65- -to 70~ conventional sodium, barium or magnesium catalyzed phenolic resin combined with 35 to 30% urea.
For the same reasons, the resin may be used satisfac-torily in binders containing 70% or more of conventional alkylated amine copolymer resin of the type disclosed in U. S. Patent No.
3,624,246, issued November 30, 1971 entitled "Alkylated Amine Copolymers" of Deuzeman et al, in U. S. Patent No. 3,487,048 _ 5 _ : :. .

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issued December 30, 196~ ~f Deuzeman enti~led "~eh~lated ~el~ine-Formaldehyde Condensate" and in U. S. Patent No. 3,432,453 issued March 11, 1969 of Gladney and Deuzeman.
The use of the present calcia catalyzed system offers other practical technical and economical advantages over conven-tional systems as follow from the materials used and the composition of the condensation reaction products.
Referring to the commonly accepted A-B-C stages in the cure of a phenolic resin the high percentage of calcium catalyst 1~ results in a phenolic resin with a long A ~B stage, good flow characteristics in the B stage, and a short curing time from B to C stage. Thus, the present resins and binders produced therefrom ; do not tend to pre-cure at the point of application (which adversely affects operation and product~ but do cure at least as rapidly in the curing ovens as resins used heretofore.
l As is known in the art, conventional barium or soda -~ catalyzed phenol-formaldehyde resins must be neutralized upon ter-minating the condensation reaction ("resin coo.~") otherwise they will continue to react. In contrast, the calcia catalyzed resins 2Q have been found to be very stable. In some cases, material has been stored in its non-neutralizing state at up to 70 F for several -months without deterioration. Normally, the resin cook will be "neutralized" after reaction either lmmediately, or at the time of using the resin, however, for some end uses this may not be necessary at all. There are several known ways of neutralizing when required.
In the case of soda (Na20) or potassia (K20) catalyzed j resins neutralization with acids such as hydrochloric acid, sul-furic acid or carbonic acid, soluble salts are formed in the aqueous resol solution, in quantities potentially objectionable for the use of such resins in certain end uses, for example the bonding of glass fibres. Upon the neutralization of barium hy-',~' ., ~
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droxide catal~st ~ith sulfu~c ~c~d, a precipitate hay~ng a high specific gravity of 4.5 is ~ormed, and it must be ultra-fine in order to avold settling during storage and other operations. Sim-ilarly, barium carbonate has a spec:ific gravity of 4.3, whereas calcium sulfate and calcium carbonate have a specific gravity of 2.9 and 2.8 respectively. These ca:lcium salts appear to resist settling in particle sizes as large as 1 to 2 microns and it does not appear necessary to obtain colloidal particle size (0.1 micron).
Using catalyzation with caustic soda or barium hydrate in conventional concentrations, the resulting resins cannot be cooked long enough to react all free phenol without simultaneously forming water-insoluble phenyls and other reaction products, which tend to agglomerate upon dilution with water and other binder in-gredients to form objectionable gummy masses in the binder circu-lation system, filters, spray nozzles, and the like.
One of the requirements for binder resins is a very high degree of water miscibility, or dilutabillty. It is common to require miscibility of the resin with no less than 500% of water but preferably with 2000% or more ("infinite dilutability") without ~;
2Q clouding~ By the use of the process of the present invention, a resin may be obtained which contains a minimum of these objection-able water insoluble reaction products.
If a resin has an excessi~e amount of monomethylolphenol a binder formed therefrom may be found objectionable. The mono-; methylolphenol being relatively volatile will on application be entrained in the effluent gas stream and resist removal therefrom.
The monomethylolphenol should be maintained at a level low enough to minimize this effect. A suitable range of monomethylolphenol ' is from 1.5~ down to 0.075~ of the weight of the liquid resin.
Similarly, the higher phenyls are objectionable in high concentrations because they are poorly soluble in water and will precipitate out on dilution of the resin suspension or solution ....... . .

in forming a binder. Accordingly, the concentration of the higher phenyls should be kept below the level at which such objectionable precipitates will form on dilution. This level will also be different for each system and may be ascertained where re-quired. The higher phenyls do not exceed 1.5% of the total peak height of the silylized resin when run through a gas chromato-graph.
The phenol/formaldehyde resin product was examined using gas chromatography by silylization as follows. To a small sample of resin is added a silylizing agent, in this case'N,O-Bis (Tri methylsilyl)-Trifluoroacetamide (BSTFA) in slight excess of two-fold and the two were allowed to react.
The BSTFA donated a Si(CH3)3 group which replaces labile H2 and forms trimethylsilyl derivatives, which are stable and may be chromatographed within the operating temperature limit of the column, with excellent separation, up to the di-phenyl with 4 methylol substitutions.
The resins produced in accordance with the present in-vention may be used in a wide variety of aqueous binder formula-, tions as previously stated.
In the present examples the cone efficiency test was carried out following the method and apparatus for evaluating resin or binder systems as described by A. Simison in U. S. Patent 2,653,473. It serves to determine the percentage o resinous pro-ducts retained during application to mineral fibres, in relation to those lost by volatilization under conditions closely simula-ting those experienced in manufacture.
The use of such resin solutions which are further mixed with a monomer before combining with other materials to form a binder formulation is preferable to the alternative of preparing a so-called copolymer resin, in which the other non-phenolic mono-mer, such as urea, is added to the mixture of phenol and formal-.,.. , ~ ...

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dehyde durlng the condensation there~f. A successful copolyme~resin cook cylce is not only dependent on the ratio of formalde-hyde to other monomers and on the type and concentration of cata-lyst used but to a great degree its success depends on the stabil-ity Qf the reaction products formed during the cook, which products are all competing for the a~aila~le free formaldehyde in the cook.
Therefore, temperatures and sequences of additions of monomers are critical and so is the free ~ormaldehyde level in the cook at the points of various additions. It is sometimes also necessary lQ to vary the temperature and pH during the cook. Storage life of the resulting copolymer resins are usually short ~ven when cooked and stored under optimum conditions if high water tolerances have to be met.
Many of these difficulties are overcome by the present invention which involves reacting phenol and formaldehyde separ- ;
ately under more easily controlled conditions. In accordance with the present invention a phenol formaldehyde resin is cooked to ;~
optimum properties and held in storage until needed. Another resin such as a urea resin or urea copolymer may also be cooked to 2Q optimum properties and similarly stored. The phenol formaldehyde resin may be combined with a monomer such as urea, and any addi-tional resins such as amine resin, especially urea resin, before the application of the binder to a substrate. By this means, each resin may be produced, tested and stored at its optimum properties and no interferences or competition occurs for the different types of monomers with the formaldehyde during the cook.
I Among the monomers which are considexed suitable for j addition to the phenol formaldehyde resin in forming a binder are amines such as urea, dicyandiamide, ketones such as acetone, 3Q alcohols, such as methanol and glycols, and the like.
In carrying out the resin condensation reaction, a reasonable amount of water should be present. If -too little _ g _ ... .

water is present, heat ey~lution is excessive, and the selectivit~
of the substitution reaction suf~ers. Too much water will slow the reaction time down and may also result in slower-setting resins.
However, the amount of water present is otherwise not critical.
The temperatures of the reaction are normally not raised above 155F. as hlgher temperature encourages the excessive co-condensation and the formation of insoluble products. This tem-perature is preferably to be reached from a charge temperatures of 70 F. or below in either a linear increase over 60 minutes or in 1~ a stepwise increase whereby a first hold temperature no higher than 125F. is maintained for 60 minutes approximately. The con-densation reaction is preferably arrested by cooling to 100F. or below at a predetermined free formaldehyde content, which may range from 3 to 16% by weight of the total charge, before any planned neutralization of the catalyst is effected.
The neutralization of the catalyst is preferably conduc-ted in such a fashion that a micron or sub-micron size precipitate is formed which is essentially non-settling in the resol solutions.
The following examples are intended to exemplify the 2Q principles underlying the present invention and are not intended to be limiting in their scope. The unmodified resin produced in Examples 1 to 7 was sampled~ and characteristics of the samples T~ere tested. The percentage of organic solids was determined by - heating in a drying oven. The gel time at 266F was determined in a steam heated brass cup. The free phenol was determined by gas . ,.
chromatography. The resins produced in these Examples were modi-fied in various ways and produced superior aqueous binders for glass fiber.
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3Q Laboratory preparation of a calcia catalyzed resin of a charge ratio ~starting ratio) of 1 mol phenol to 2.8 formaldehyde.

` Charge Ratio: phenol: formaldehyde ~r 1 2 ~ 8 .

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Ingredients:
formaldehyde ~ aqueous - 44% solution 1995 gms phenol - USP 98~ 1005 gms calcium oxide ~ Ashgrove Springfield sn ~ 7 gms high calcium pebble quickline ~3.5% Ca based CaO 96.3% - ground to (-10) on weight of mesA on U. S. standard scale phenol~

Procedure:
The formaldehyde was placed in a 3 liter glass reactor. ;~
The agitator was started~ phenol was added, and then calcium oxide la was added. The temperature was allowed to rise to 125F. in a period of about 1 hour. The temperature was held at 125F. for 30 minutes. The temperature was increased to 150 F. in 30 minutes.
The temperature was held at 150F. until the free formaldehyde was 4.5% and then cooled to 75F. The pH at the end of reaction was 8.70. `' The resin was neutralized with CO2-to a pH of 7.3.
Results:
Organic solids: 48.44 Gel time at 266F. 528 seconds 2~ Free phenol: 1.8 EXA*IPLE 2 '~
Production of a calcia catalyzed resin of the starting '`
- ratio 1 mol phenol to 2.8 mol formaldehyde, suitable for use in binders particularly, in varying combinations with urea.
Charge Ratio: 1:2.8 ' Batch'Size: 2000 gals.
Ingredients:
formaldehyde - aqueous - 44% solution 1375 imp. gals. ' phenol - USP 98~ 743 imp. gals.

3a calcium oxide - Beachville rotary crushed high calcium quick-lime CaO 92~ 3)mesh on U. S. standard scale 406 lbs.
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~' ' ' Procedure:
The 3000 gals. reactor was loaded with formaldehyde and phenol. The agitator was started. The catalyst (calcium oxide) was poured in over a period of 15 minutes. When all the catalyst was loaded, the temperature was allowed to rise 125F. in 1 hour.
The temperature was held at 125 F. for 1 hour. The temperature was increased to 150F. over a period of 25 minutes. The temper- ~' ature was held at 150 F. for about 1-1/4 hours to a free formal dehyde of 4-1/2%. The mixture was cooled to 80F. The pH at the end of reaction was 8.40.
The resin was neutralized with CO2 to a pH of 7.23.
Results:
Qrganic solids: 48.66% Cone efficiency: 73%
Gel time at 266 F.: 640 seconds Free phenol: 2.06%
''EXAMPLE`'3 Charge Ratio:~ 1:3.1 ~ ' ' I'ngred'ients:
formaldehyde - aqueous - 44%2030 gms phenol - USP 98% 920 gms.

calcium oxide - Beachville rotary crushed high calcium quick-lime-CaO 93.5% -(-3) mesh 53.9 gms (4% Ca on U. S. standard scale based on phenol) Proced'ure !
, Formaldehyde was poured into the glass reactor, and the agitator was started. The phenol was added, followed by the cal-cium oxide. The temperature was raised to 120F. in a period of about 30 minutes. The temperature was held at 120~F. for a period of 3 hours. The temperature was raised to 140F. in 48 minutes.
3Q The temperature was held at 140F. for 43 minutes. The tempera-ture was then raised to 150F. The mixture was cooked at this temperature until a free formaldehyde of 5.5%. Then it was ~' ;
:,:, '' -, . ' cooled to 75F. The pH a-t the end of reaction was 7.9 The resin was neutralized with CO2 to a pH of 7~2 Results~
Organic solids: 45.61~ Cone efficiency: 78.4%
Gel time at 266F: 509 seconds I Free phenol: 0~82%
j EXAMPLE 4 Charge Ratio: phenol:formaldehyde 1:3.5 Ingredients:
lQ formaldehyde - aqueous - 44~ solution 2139.3 gms phenol - USP 98% 860.7 gms calcium oxide - Ashgrove Springf~eid high calcium pebble quicklime - CaO 96.3% - ground to (-10) 49.06 gms (4% Ca mesh on U. S. standardbased on phenol) Procedure:
.
The formaldehyde was poured into the glass reactor. The I agitator was started. Phenol was added, followed by calcium oxide.
The temperature was allowed to rise to 100F. The mixture was - held at that temperature for 45 minutes. The temperature was -¦
2Q increased to 110F, in 30 minutes period, and held at that tem-perature for 1 hour and 30 minutes. The temperature was raised to 120F. in 30 minutes, and held for 1 hour. The temperature : . ~
was raised to 130F in 30 minutes, and held for 1 hour. The tem-perature was raised to 150F. and held at that temperature till a free formaldehyde of 8.60%. The mixture was cooled to 75F. The pH at the end of reaction was 8.3 The resin was neutralized with CO2 to a pH of about 7.2 ~;
Results:
Organic solids: 42.8~ Cone efficiency: 83.4%
3Q Gel time at 266 F.: 503 seconds , .
Free phenol: 0~38~

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~XAMPLE 5:
Production of a calcia catalyzed resin of the starting ratio 1 mol phenol to 3.7 mol formaldehyde, suitable for use in binders particularly, ln varying combinations with urea.
Batch size; 3000 gals.
Ingredients;
Formaldehyde ~ aqueous 44% s~lution 2235 gals.
phenol - U~S.P. 98~ 912 gals.
Ca~QH12~Beachville Chemical Hi~h Calcium Hydroxide Powder lQ taken as 99~ pure880 lbs.
Procedure:
The 3,000 gals. reactor was loaded with formaldehyde and phenol. The agitator was started. The catalyst (Ca(OH)2) was poured in over a period of about one hour and 35 minutes.
The temperature at this point was about 86 F. It was held at 86F for about 25 minutes, then the temperature was raised to 110F in 32 minutes. The temperature was held at 110F for about 28 minutes. The temperature was increased to 125F in 20 ~ -minutes. The temperature was held at 125 F for about 40 minutes.
2Q The temperature was increased to 150 F in 50 minutes. The temper-ature was held at 150F for about 55 minutes to a free formalde-hyde of 8.20~. The mixture was cooled to 80F. The final pH was 8.55.
Results~
Free phenol - 0.3%
The resin was neutralized with carbon dioxide to a pH ~;
of 7.8 Organic solids: 44.5 Gel time at 266F: 512 seconds Results of silylization and gas chromatographic study of resulting 1:3.7 Resin, as charted. From the chart the ratios of chosen peaks were calculated.
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phenol - 3.9 ' O-methylol - 6.3 P-methylol 4.4 O-p di-methylol - 11.7 2,4,6-tri-methylol - 57.3 ~ di-phenyl - 16~4 -I (4) EXAMPLE 6:

Production of a calcia catalyzed resin of the starting ratio 1 mol phenol to 3.8 mol formaldehyde, suitable for use in binders, particularly in varying combinations with urea.

Batch s-i-ze: 2400 gals.

Ingredients:

Formaldehyde- 1804 gals. ~;

Phenol - 721 gals.

Ca(OH2) - Hlgh Calcium Beachville chemical hydroxide - Power Ca(OH~2 taken as 91.4% - 750 lbs.
., , Procedure:
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The 3,000 gal~ reactor ~as loaded with formaldehyde and 2Q phenol~ The agitator was started~ The catalyst (calcium hydroxide) was poured in over a period of three hours~ The temperature was allowed to rise to 84 F~ When all the catalyst was loaded, the temperature was allowed to rise to 90F. then 100F and then to 110 F. All these steps were carried out within one hour. The tem-perature was h~Id at 110F for about 1/2 hour. The temperature was increased to 120F in 15 minutes. The temperature was held o at 120 F for about 15 minutes. The temperature was increased to 130F in ahout 15 minutes. The temperature was held at 130F for about one hour. The temperature was increased to 140 F in about ~ .
3Q 30 minutes. The temperature was allowed to rise to 147F in about 26 minutes. The temperature was held at 147F. for about 30 min-utes to a free formaldehyde of 10.5%. The mixture was cooled to 76 F. The pH at the end of re~ction was 8.45.
The resin was neutralized with CO2 to a pH of 7.2.
Results:
Organic solids: 39.63~
Gel time at 266 F: 711 secs.
Free phenol: .14%
EXAMPLE 7:
Charge Ratio: phenol:formaldehyde 1:4 Ingredients:
formaldehyde - aqueous - 44% solution2218.80 gms phenol - USP 98% 781.20 gms calcium oxide - Ashgrove Springfield high calcium pebble quicklime - CaO
96.3~ ground to (-10) mesh on U. S. standard 55.7 gms Procedure:
The formaldehyde was poured into the glass reactor.
The agitator was started. Phenol wa~ added, followed by calcium oxide. The temperature was raised to 100F. in a period ;
of 10 minutes and the temperature was held at this point for 25 minutes. The temperature was raised to 110F. in 30 minutes, and held at this point for 1 hour. The temperature was raised to 120F. in 30 minutes, and held there for 1 hour. The temperature was raised to 130F. in 30 minutes, and held for 1 hour. The temperature was raised to 140F. in 30 minutes, and held there until a free formaldehyde of 10.7%. The mixture was cooled to 75F. The pH at the end of the reaction was 8.6.
The resin was neutralized with CO2 to a pH of about 7.2.
Results:
Organic solids: 40.2% Cone efficiency: 82.4%
Gel time at 266 F: 655 seconds Free phenol: 0.29%
EXAMPLE 8:
Binder preparation:
135 grams of nearly neutral phenolic resin resulting from Example 1 (1:2.8 charge ratio - 48.44~ organic solids) was - 16 ~
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mixed wlth 10 gra~s o ~ 10~ ~mmoni,u~ sulphate solution.~ Then 35 grams of urea were added. This was mixed well until the urea was fully dissolved. The ~ollowing were added to the mixture: 1 gram of ammonium hydroxide, 1 gram of a 10~ silicone solution and 20 grams of a 50~ oil emulsion~ The mixture was diluted further down to 20% organic solid ~y adding 350 grams of water. The resulting co-condensation product was found t:o have very satisfactory charac- ', teristics for ~inder formulation. It had a standard tensile strength ~psi) of 717 dry and 442 wett and had a gel time of 740 ~ ' seconds at 266 F~
i EXAMPLE 9:
Laboratory preparation of a calcia catalyzed resin of a starting ratio of 1 mol phenol to 3.6 moles formaldehyde.
Charge ratio: phenol:formaldehyde - 1:3.6 Ingredients:
.. , - formaldehyde - aqueous - 44% sol.2077 gms phenol - USP 98% 809 gms Calcium hydroxide (99.3%) 73.9 gms Procedure:
2Q ' The formaldehyde and phenol was loaded in the 3 liter glass reactor. The agitator was started. Then the calcium hy- ~ ;
droxide was added. The temperature was allowed to rise to 100F.
The temperature was held at 100F for about 1 hour. The tem-perature was increased to llOOF. The temperature was held at 110F for about 1 hour. The temperature was increased to 125 F.
The temperature was held at 125F for about 1 hour. The tempera-ture uas increased to 140 F. The temperature was held at 140F
for about 1 hour. The temparature was increased to 150F. The temperature was maintained at 150 F until the free formaldehyde was 8.45%, and then cooled to room temperature. The pH at the ,~ end of the reaction was 8.50.

, - 17 -:' Results:
Organic solids - 41,38% Tensile strength ~ Dry - 852 psi.
~et - 504 psi % Free phenol - .2%
Estimated gel time at 266 F for a neutralized resin P~ 7 5 r was 500 secs.
The resin was incorporated into binder formulation having the following composition:
54~ Calc~a catalyzed phenol formaldehyde resin; ratio 1.3~6 46% urea 1% CNH4~2 SO4 0.1% A-1120 silicone The resulting binder was very satisfactory for the bonding of glass fi~re mats as well as other applications.
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Claims (13)

1. A method for making an infinitely dilutable low phenol aqueous solution of thermosettable phenol formaldehyde resin, by selectively catalyzing and controlling the methylola-tion of phenol with formaldehyde to increase resinification, mini-mize the content of monomethylol phenols and higher phenyls and maximize the content of 2,4,6-trimethylol phenols, thus producing a resin solution component for binder formulations having low air and wash water polluting characteristics when applied to a sub-strate, comprising the steps of:
(a) mixing U.S.P. phenol, in the absence of other mono-mers, with aqueous formaldehyde, in an amount of 2.8 to 4.5 moles of formaldehyde per mol of phenol, (b) introducing a calcium oxide or calcium hydroxide catalyst, with cooling, in an mount of 3 to 5.5 percent as calcium (Ca) based upon the weight of phenol, (c) controlling the exothermic rise in the temperature of the reactants without heat input so as to increase to not more than about 125°F during at least the first hour of reaction, (d) continuing the methylolation reaction without heat input at a suitable temperature up to 155°F, and (e) terminating said reaction by cooling when the condensation reaction product is substantially phenol-free, and is still water soluble.

2. A method as in claim 1 wherein the formaldehyde is introduced in an amount of 3 to 4 moles per mole of phenol.

3. A method as in claim 1 wherein the range of formal-dehyde in step (a) is 3.5 to 4, and the range of calcium in step (b) is 4.5 to 5.

4. A method as in claim 1 wherein the formaldehyde is introduced in an amount of 3.8 moles per mole of phenol.

5. A method as in claim 1 wherein the reaction is carried out for a period of 3 to 10 hours.

6. A method as in claim 1 wherein the temperature in step (a) is maintained no higher than 84°F.

7. A method as in claim 1 wherein the pH is in the range of 8 to 9.5.

8. A method as in claim 1 wherein the pH is in the range of 8.3 to 9.5

9. A method as in claim 7 further comprising the step of bringing the reaction product to a pH of 7 to 7.6 by addition of an acid.

10. A method as in claim 9 wherein the acid is chosen from sulfamic, phosphoric, sulfuric, acetic, maleic, and carbonic acids, and their ammonium salts.

11. A continuous method as in claim 1 for making infin-itely dilutable substantially phenol free aqueous solutions of thermosettable phenol formaldehyde resins, by selectively cataly-zing and controlling the methylolation of phenol with formaldehyde to increase resinification, minimize the content of monomethylol phenols and higher phenyls, and maximize the content of 2,4,6-trimethylol phenols, thus producing a resin solution component for binder formulations having low air and wash water polluting characteristics when applied to a substrate, comprising the steps of:
(a) continuously mixing U.S.P. phenol, in the absence of other monomers, with aqueous formaldehyde in an amount of 2.8 to 4.5 moles of formaldehyde per mol of phenol, continuously in-troducing calcium oxide or calcium hydroxide catalyst with cooling up to or near its solubility limit in the aqueous mixture present, in an amount of 3 to 5.5 percent as calcium (Ca) based upon the weight of phenol, while maintaining a temperature of not exceeding about 84° F., (b) controlling the exothermic rise in temperature of the reactants without heat input so as to increase to not more than about 125°F during at least the first hour of reaction, (c) continuing the methylolation reaction without heat input at a suitable temperature up to 155°F, and (d) terminating said reaction by cooling when the con-densation reaction product is substantially phenol free and is still water soluble.

12. An aqueous solution of an infinitely dilutable ther-mosettable phenol formaldehyde condensation resin, said resin characterized as follows:
(i) not over about 2% unreacted phenol by weight, (ii) between 3 to 16% unreacted formaldehyde, by weight, (iii) between 2.3 to 2.7 methylol groups per phenol molecule, (iv) low content of water insoluble higher phenyls, (v) low content of monomethylolphenol, said solution being prepared by selectively catalyzing and con-trolling the methylolation of 1 mol of phenol with 3.2 to 4.4 mols of formaldehyde with calcium oxide or hydroxide to suppress the formation of monomethylol phenols and higher phenyls, and to favour the formation 2,4,6-trimethylol phenol.

13. A resin solution as in claim 12 containing less than 0.2% unreacted phenol by weight.