BACKGROUND OF THE INVENTION
The invention relates to acetylenic diol alkylene oxide adducts, their manufacture and their use to reduce the surface tension in water-based systems. In another aspect it relates to the use of such adducts as a wetting agent in aqueous photoresist developers.
The ability to reduce the surface tension of water is of great importance in waterborne coatings, inks, adhesives, and agricultural formulations because decreased surface tension translates to enhanced substrate wetting in actual formulations. Surface tension reduction in water-based systems is generally achieved through the addition of surfactants. Performance attributes resulting from the addition of surfactants include enhanced surface coverage, fewer defects, and more uniform distribution. Equilibrium surface tension performance is important when the system is at rest. However, the ability to reduce surface tension under dynamic conditions is of great importance in applications where high surface creation rates are utilized. Such applications include spraying, rolling and brushing of coatings or spraying of agricultural formulations, or high-speed gravure or ink-jet printing. Dynamic surface tension is a fundamental quantity which provides a measure of the ability of a surfactant to reduce surface tension and provide wetting under such high-speed application conditions.
Traditional nonionic surfactants such as alkylphenol or alcohol ethoxylates, and ethylene oxide (EO)/propylene oxide (PO) copolymers have excellent equilibrium surface tension performance but are generally characterized as having poor dynamic surface tension reduction. In contrast, certain anionic surfactants such as sodium dialkyl sulfosuccinates can provide good dynamic results, but these are very foamy and impart water sensitivity to the finished coating.
Surfactants based on acetylenic glycols such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol and its ethoxylates are known for their good balance of equilibrium and dynamic surface-tension-reducing capabilities with few of the negative features of traditional nonionic and anionic surfactants.
For many applications it would be desirable to produce acetylenic diol derivatives which have alternative properties. For example, in applications in which excellent dynamic performance is required, it is often desirable to have a surfactant which has higher critical aggregation concentration (solubility limit or critical micelle concentration) because higher bulk surfactant concentrations lead to a higher diffusive flux of surfactant to newly created surface, and consequently lower dynamic surface tension. Traditionally, acetylenic diol surfactants with higher water solubility have been obtained by reaction of the parent with ethylene oxide; greater degrees of ethoxylation provide greater water solubility. Unfortunately, increasing the level of ethoxylation also introduces a tendency to foam, introducing inefficiencies during formulation, defects during application, and process issues in other applications. The problem of foaming is particularly troublesome in photoresist developers used in semiconductor fabrication.
The demands of semiconductor manufacture have required the use of high performance surfactants and wetting agents in photoresist developer formulations. As line features shrink to smaller sizes and photoresist substrate materials become more aliphatic in nature (i.e. having lower surface energy), aqueous developer solutions are being formulated with surface tension reducing agents. Another requirement for these developers is that they have a low tendency to foam. This is accentuated by the movement toward larger wafer sizes. Low foam formation is particularly important when using spray-puddle techniques because microbubble entrainment during spreading of the solution over the photoresist surface can lead to defects. Surfactants that have been used in the past to increase wetting of the photoresist typically lead to higher foam formation. For the most part the industry has focused on the effect of surfactant on photoresist performance, such as contrast, critical dimension, and feature sharpness. Although the cleaning ability of underlying substrates is enhanced by typical surfactants, foam formation still remains a problem.
Low dynamic surface tension is of great importance in the application of waterborne coatings. In an article, Schwartz, J. “The Importance of Low Dynamic Surface Tension in Waterborne Coatings”, Journal of Coatings Technology, September 1992, there is a discussion of surface tension properties in waterborne coatings and a discussion of dynamic surface tension in such coatings. Equilibrium and dynamic surface tension were evaluated for several surface-active agents. It is pointed out that low dynamic surface tension is an important factor in achieving superior film formation in waterborne coatings. Dynamic coating application methods require surfactants with low dynamic surface tensions in order to prevent defects such as retraction, craters, and foam.
Efficient application of agricultural products is also highly dependent on the dynamic surface tension properties of the formulation. In an article, Wirth, W.; Storp, S.; Jacobsen, W. “Mechanisms Controlling Leaf Retention of Agricultural Spray Solutions”; Pestic. Sci. 1991, 33, 411-420, the relationship between the dynamic surface tension of agricultural formulations and the ability of these formulations to be retained on a leaf was studied. These workers observed a good correlation between retention values and dynamic surface tension, with more effective retention of formulations exhibiting low dynamic surface tension.
Low dynamic surface tension is also important in high-speed printing as discussed in the article “Using Surfactants to Formulate VOC Compliant Waterbased Inks”, Medina, S. W.; Sutovich, M. N. Am. Ink Maker 1994, 72 (2), 32-38. In this article, it is stated that equilibrium surface tensions (ESTs) are pertinent only to ink systems at rest. EST values, however, are not good indicators of performance in the dynamic, high speed printing environment under which the ink is used. Dynamic surface tension is a more appropriate property. This dynamic measurement is an indicator of the ability of the surfactant to migrate to a newly created ink/substrate interface to provide wetting during high-speed printing.
Tetramethylammonium hydroxide (TMAH) is the chemical of choice in aqueous alkaline solutions for developing photoresists according to Microlithography, Science and Technology, edited by J. R. Sheats and B. W. Smith, Marcel Dekker, Inc., 1998, pp 551-553. Surfactants are added to the aqueous TMAH solutions to reduce development time and scumming and to improve surface wetting.
U.S. Pat. No. 5,098,478 discloses water-based ink compositions comprising water, a pigment, a nonionic surfactant and a solubilizing agent for the nonionic surfactant. Dynamic surface tension in ink compositions for publication gravure printing must be reduced to a level of about 25 to 40 dynes/cm to assure that printability problems will not be encountered.
U.S. Pat. No. 5,562,762 discloses an aqueous jet ink of water, dissolved dyes and a tertiary amine having two polyethoxylate substituents and that low dynamic surface tension is important in ink jet printing.
In applications which require good dynamic performance and low foaming, acetylenic glycol-based surfactants have become industry standards. The following patents and articles describe various acetylenic alcohols and their ethoxylates as surface-active agents:
U.S. Pat. No. 3,268,593 and Leeds, et al, I
&EC Product Research and Development
1965, 4, 237, disclose ethylene oxide adducts of tertiary acetylenic alcohols represented by the structural formula
wherein R1 and R4 are alkyl radicals having from 3-10 carbon atoms and R2 and R3 are methyl or ethyl and x and y have a sum in the range of 3 to 60, inclusive. Specific ethylene oxide adducts include the ethylene oxide adducts of 3-methyl-1-nonyn-3-ol, 7,10-dimethyl-8-hexadecyne-7,10-diol; 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 4,7-dimethyl-5-decyne-4,7-diol. Preferably, the ethylene oxide adducts range from 3 to 20 units. Also disclosed is a process for the manufacture of materials of this type using trialkylamine catalysts.
U.S. Pat. No. 4,117,249 discloses 3 to 30 mole ethylene oxide (EO) adducts of acetylenic glycols represented by the structural formula
wherein R is hydrogen or an alkenyl radical. The acetylenic glycols are acknowledged as having utility as surface-active agents, dispersants, antifoaming nonionic agents, and viscosity stabilizers.
U.S. Pat. No. 5,650,543 discloses ethoxylated acetylenic glycols of the form
where x and y are integers and the sum is from 2-50. These surfactants are notable because they impart an ability to formulate coating and ink compositions capable of high-speed application.
JP 2636954 B2 discloses propylene oxide adducts of formula
where R=C1-8 alkyl; m+n=integer 1 to 100. These compounds are prepared by reacting acetylenic glycols and propylene oxide in the presence of Lewis acid catalysts such as BF3. It is stated that amine catalysts are inactive for the addition of propylene oxide to acetylenic diols. The propylene oxide adducts are said to be useful as wettability improvers for antirust oil, antifoamers, spreaders for pesticides, and wetting agents for adhesives. They are effective in improving wettability of oils and have improved antifoaming ability.
JP 2621662 B2 describes dye or developing agent dispersions for thermal recording paper containing propylene oxide (PO) derivatives of an acetylenic diol of the form
where R1 and R2 are —CH3, —C2H5, —C4H9; R3 and R4 are —(OC3H4)mOH, or —OH where m is an integer 1-10.
JP 04071894 A describes coating solutions containing a dispersion of a colorless electron donating dye precursor and a dispersion of developer. At least one of them contains at least one type of wax having a melting point of at least 60° C. and at least one EO or PO derivative of an acetylenic diol of the formula
where R1 and R4 each represent methyl, ethyl, propyl, or butyl and R2 and R3 are each —(OC2H5)nOH, or —(OC3H6)nOH (n is 1-10), or OH, mixed and dispersed.
JP 2569377 B2 discloses a recording material containing dispersions of a substantially colorless electron donating dye precursor and a developer. When at least one of these dispersions is prepared, at least one of the compounds
where R3 and R6=methyl, ethyl, propyl or butyl; and R4 and R5=—(OC2H4)mOH, —(OC3H6)mOH (where m=an integer of 1-10) or —OH is added.
JP 09150577 A discloses a heat sensitive recording medium which contains in the heat sensitive layer a leuco dye and 0.1-1.0 wt % of an ethoxylate or propoxylate of an acetylenic glycol of the form
where R1=methyl, ethyl, propyl or butyl; R2=hydrogen or methyl; and n and m=1-10.
JP 04091168 A discloses silica which has been surface treated with compounds of the form
where R1=1-8C alkyl, A=2-3C alkylene glycol residue, R1 and A in a molecule may be the same or different, x and y=each an integer of 0-25.
JP 06279081 A describes a manufacturing process for a cement mortar-concrete hardening material to which 0.5-10 wt. % an acetylenic alcohol or diol alkoxylate is added together with fluorine group surfactants and/or silicon group surfactants. The acetylenic material can be expressed by the formula
where R1=H or —C(R2)(R3)(O(AO)nH); R2 and R3=1-8C alkyl radicals, A=2-3C alkylene radicals and n=0-30.
JP 03063187 A discloses the use of acetylenic glycol ethylene oxide and/or propylene oxide addition products in concentrated aqueous fountain solution compositions for offset printing. In one example, the 8 to 12 mole ethylene oxide/1 to 2 mole propylene oxide adduct of 3,5-dimethyl-4-octyne-3,5-diol is used in a fountain solution. Other examples illustrate the use of only ethylene oxide derivatives of acetylenic diols.
Although acetylenic diol derivatives containing both ethylene oxide (EO) and propylene oxide (PO) have been taught as a general class of materials, usually as potential extensions of work which had been performed with ethylene oxide derivatives, no actual examples of an acetylenic diol EO/PO derivative based upon 2,4,7,9-tetramethyl-5-decyne-4,7-diol or 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol have been prepared and evaluated. There are no disclosures of any process that could be used to prepare materials of this type.
The use of surfactants in photoresist developer compositions has been known for at least two decades.
U.S. Pat. No. 4,374,920 discloses using a non-ionic surfactant in an aqueous alkaline developer composition for positive-working lithographic printing plates and photoresists. The surfactant was tetramethyl decynediol or ethoxylated tetramethyl decynediol. The specific surfactants were SURFYNOL® 440, 465 and 485 surfactants of Air Products and Chemicals, Inc.
U.S. Pat. No. 4,833,067 discloses aqueous developing solutions for positive-working photoresist compositions containing an organic basic compound free from metallic ions, such as tetramethylammonium hydroxide and choline, as the main ingredient and 50 to 5000 ppm of an acetylenic alcohol. These aqueous developing solutions are said to have increased surface wetting and decreased foaming.
U.S. Pat. No. 5,069,996 discloses photoresist developer compositions containing TMAH, novolak resin, an ethoxylated tetramethyidecynediol surfactant, a defoamer and water.
U.S. Pat. No. 5,756,267 discloses developing solutions useful in the manufacture of liquid crystal displays. These solutions contain water, a quaternary ammonium base such as TMAH, a quaternary ammonium salt surface active agent, an alkanolamine and an acetylenic alcohol based surface active agent which is the same as those disclosed by the '067 patent.
U.S. Pat. No. 5,922,522 discloses developing solutions for photoresists containing an anti-scum agent which is a mixture of an ethoxylate surfactant and a propoxylate surfactant. Although no example of such a compound is given, it is said that the ethylene oxide units and the propylene oxide units can be incorporated in a chain in the same molecule. These surfactants are said to be preferably anionic and have a hydrophobic end on the molecule formed from alcohols such as nonylphenol, octylphenol, and tristyrylphenol.
JP 10-319606 discloses a photoresist developer containing water, alkaline substance, and a block copolymer having the formula HO—A—B—A—H wherein A and B are a polyethylene oxide group or a polypropylene oxide group, the molecule containing both groups. These block copolymers, however, are very susceptible to forming micelles which can cause surface defects in microelectronic applications.
In spite of all the advances in this field of semiconductor manufacture, the need continues to exist for new surfactants which can efficiently lower surface tension in a developer as it is applied to an exposed photoresist while minimizing foam production.
SUMMARY OF THE INVENTION
This invention provides alkoxylated acetylenic diols that act as surfactants for water based compositions of the following structure:
where r and t are, preferably the same, 1 or 2, (n+m) is 1 to 30 and (p+q) is 1 to 30. The EO and PO units may be distributed along the alkylene oxide chain in blocks of EOs and POs or randomly.
This invention also relates to processes for the manufacture of certain alkoxylated acetylenic diols.
Another embodiment of the invention affords water-based compositions containing an organic or inorganic compound, particularly aqueous organic coating, ink, agricultural and electronics cleaning compositions, having reduced equilibrium and dynamic surface tension by incorporation of an effective amount of an alkoxylated acetylenic diol of the above structure.
By “water-based”, “aqueous” or “aqueous medium” we mean, for purposes of this invention, a solvent or liquid dispersing medium which comprises at least about 90 wt %, preferably at least about 95 wt %, water. Obviously, an all water medium is also included and is most preferred. Also for purposes of the present invention, the terms “photoresist developing” and “electronics cleaning” are interchangeable.
It is desirable that an aqueous solution of the alkoxylated acetylenic diol demonstrates a dynamic surface tension of less than 35 dynes/cm at a concentration of ≦0.5 wt % in water at 23° C. and 1 bubble/second according to the maximum-bubble pressure method. The maximum-bubble-pressure method of measuring surface tension is described in Langmuir 1986, 2, 428-432, which is incorporated by reference.
Also provided is a method for lowering the equilibrium and dynamic surface tension of aqueous compositions by the incorporation of these alkoxylated acetylenic diol compounds.
Also provided is a method for applying a water-based inorganic or organic compound-containing composition to a surface to partially or fully coat the surface with the water-based composition, the composition containing an effective amount of an alkoxylated acetylenic diol compound of the above structure for reducing the dynamic surface tension of the water-based composition.
There are significant advantages associated with the use of these alkoxylated acetylenic diols in water-based organic coatings, inks, fountain solutions for gravure printing processes, agricultural and electronics cleaning compositions and these advantages include:
an ability to formulate water-borne compositions which may be applied to a variety of substrates with excellent wetting of substrate surfaces including contaminated and low energy surfaces;
an ability to provide a reduction in coating or printing defects such as orange peel and flow/leveling deficiencies;
an ability to produce water-borne coatings, fountain solutions and inks which have low volatile organic content, thus making these alkoxylated acetylenic diol surfactants environmentally favorable;
an ability to formulate coating, fountain solution and ink compositions capable of high speed application;
an ability to control the foaming characteristics of the water-based compositions;
an ability to formulate low surface tension aqueous electronics cleaning and processing solutions, including photoresist developer solutions, for the semiconductor manufacturing industry with good wetting and extremely low foam; and
an ability to produce some members of the class using a chemical process similar to that used to produce acetylenic diol ethoxylates.
Because of their excellent surfactant properties and the ability to control foam, these materials are likely to find use in many applications in which reduction in dynamic and equilibrium surface tension and low foam are important. Such uses include various wet-processing textile operations, such as dyeing of fibers, fiber souring, and kier boiling, where low-foaming properties would be particularly advantageous; they may also have applicability in soaps, water-based perfumes, shampoos, and various detergents where their marked ability to lower surface tension while simultaneously producing substantially no foam would be highly desirable.
The use of these materials in photoresist developer formulations is of particular importance because of their ability to provide all the advantages of surface tension lowering plus outstanding performance in reducing the formation of foam.
DETAILED DESCRIPTION OF THE INVENTION
This invention relates to compounds of the formulas A and B.
where (n+m) and (p+q) each can range from 1 to 30. It is preferred that (n+m) be 1.3 to 15 and most preferably 1.3 to 10. It is preferred that (p+q) be 1 to 10, more preferred 1-3 and most preferred 2. In Formula A, r and t are 1 or 2, especially r=t, i.e. the acetylenic diol portion of the molecule is 2,4,7,9-tetramethyl-5-decyne-4,7-diol or 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol.
The alkylene oxide moieties represented by (OC2H4) are the (n+m) polymerized ethylene oxide (EO) units and those represented by (OC3H6) are the (p+q) polymerized propylene oxide (PO) units. Products in which the EO and PO units are each segregated together are referred to as “block” alkoxylate derivatives. It is preferred the block copolymer products be capped, i.e., endcapped, with PO units.
The products in which the EO and PO units are randomly distributed along the polymer chain are referred to as “random” alkoxylate derivatives. Random derivatives can be represented by formula B
where R is hydrogen or methyl and (n+m)=2-60 with the proviso that the compound contain at least one ethylene oxide, preferably at least 1.3 EO units, and at least one propylene oxide unit, preferably at least 2 PO units, and rand t are 1 or 2, especially r=t.
The block compositions of structure A can be prepared by reaction of 2,4,7,9-tetramethyl-5-decyne-4,7-diol or 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol with the requisite quantities of ethylene oxide followed by propylene oxide in the presence of a suitable catalyst. Suitable catalysts include trialkylamines and Lewis acids, particularly BF3. Alternatively, the compositions may be prepared by reaction of a pre-formed acetylenic diol ethoxylate with propylene oxide in the presence of an appropriate catalyst. In this case of a pre-formed acetylenic diol ethoxylate, it may be possible to use KOH or other alkali catalysts to effect the reaction with propylene oxide, provided the amount of ethylene oxide which has been added is sufficient to cover essentially all of the tertiary alcohol functionality.
The preferred process for making the acetylenic diol alkoxylates uses BF3 or trialkylamine catalysts. The use of BF3 allows the rapid preparation of derivatives containing relatively large quantities of propylene oxide. However, compositions prepared with trialkylamine catalysts, especially trimethylamine, are preferred for several reasons. They can be prepared using a process very similar to that used for manufacture of acetylenic diol ethoxylates without significant byproduct chemistry. In particular, trialkylamine catalysts allow for the preparation of 2 mole propylene oxide capped derivatives in high selectivity using a highly efficient, one pot process.
With respect to the processes for the preparation of acetylenic diol EO/PO adducts, the tertiary acetylenic diol starting materials can be prepared in various known manners such as those described in U.S. Pat. No. 2,250,445; U.S. Pat. No. 2,106,180 and U.S. Pat. No. 2,163,720, which are incorporated by reference. The acetylenic diol starting material may contain from 8 to 26 carbons. It is preferred that the acetylenic diol starting material contain 14 to 16 carbons, and it is most particularly preferred that it be 2,4,7,9-tetramethyl-5-decyne-4,7-diol or 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol.
Various basic catalysts can be used to promote the reaction between the alkylene oxide and the acetylenic tertiary glycols in which the hydroxyl groups are attached to a carbon atom in a position alpha to the acetylenic bonds according to this invention. Tertiary aliphatic amines, namely trialkylamines such as trimethylamine, triethylamine, tripropylamine, dimethylethylamine, diethylmethylamine and the like, are particularly advantageous catalysts for the reaction. Such tertiary aliphatic amines catalyze the addition reaction at a rapid rate at moderately low temperatures and pressures without inducing cleavage of the acetylenic glycol. Trimethylamine is preferred because of its high catalytic activity and longevity in the reaction.
As is known in the art, the use of strongly basic catalysts such as sodium hydroxide, especially at high temperatures of about 150° C., induces cleavage of the acetylenic tertiary glycols and for this reason should be avoided, unless of course, sufficient ethylene oxide has been added to prevent substantial decomposition of tertiary acetylenic alcohol functionality. Once the tertiary hydroxyl groups of the acetylenic glycol have reacted with ethylene oxide, the resultant adduct exhibits the marked stability of an ether. So stable are the adducts that they can be heated with concentrated base such as sodium hydroxide at elevated temperatures, while comparable treatment of the initial acetylenic glycol is accompanied by extensive degradation. Consequently, strongly basic catalysts, such as the alkali metal hydroxides, can be used to increase the polyalkylene oxide chain length once the initial adducts have been formed and protected against decomposition. It is anticipated that alkali metal hydroxides could also be used to promote the addition of propylene oxide to initial EO or PO adducts with sufficiently low quantities of residual tertiary acetylenic alcohol functionality.
The trialkylamine-catalyzed addition reaction may be performed at either atmospheric (15 psig; 1 bar) or moderate to low superatmospheric pressures (30-300 psig; 2-20 bar). The use of moderate to low superatmospheric pressures is preferred since it obviates the necessity of recycling unreacted ethylene oxide and propylene oxide, and generally proceeds at faster rates than additions carried out at atmospheric pressures. The effect of pressure on rate is particularly important in the reaction with propylene oxide, and it is therefore preferred that reactions be performed at pressures in excess of 30 psig (2 bar). It is particularly preferred that the process be carried out at a pressure greater than 60 psig (4 bar). Another benefit of performing the reaction under pressure is that such reactions may be accomplished with ordinary efficient agitation, while reactions conducted at atmospheric pressure often work best when a dispersion type agitator is used. While the reaction can be carried out at lower pressure, reaction rates, and therefore reactor productivity, suffer. Performing the reaction at pressures much in excess of about 300 psig (20 bar) would likely have only marginal benefit, and would increase the cost of equipment required for manufacture. It is preferred to operate at 100 psig (6.7 bar).
The temperature at which the reaction is run for trialkylamine catalyzed reactions will depend upon the particular system and the catalyst concentration. Generally, at higher catalyst concentrations, the reactions can be run at lower temperatures and pressures. Reaction temperatures should be high enough to permit the reaction to proceed at a reasonable rate, but low enough to prevent decomposition of the reagents and products. Temperatures in the range of 40-150° C. are suitable, 50-120° C. preferred, and 70-90° C. particularly preferred.
In the trialkylamine catalyzed process in which propylene oxide is added to an acetylenic diol EO adduct, the reaction stops at a PO end cap on each chain, i.e., the obtained product is an acetylenic diol EO/PO adduct containing two PO end caps, p and q each being 1 in Formula A. When a mixture of EO and PO is added to an acetylenic diol or diol EO adduct, the trialkylamine catalyzed process affords an adduct having random EO and PO units, in the latter case extending beyond the original EO block.
To prepare the EO/PO adducts of the invention, the acetylenic glycol is liquefied by melting and the catalyst is added with stirring. Ethylene oxide and/or propylene oxide are added as liquids with stirring and the reaction is concluded when the desired polyalkylene oxide chain length is reached as determined by gel permeation chromatography (GPC), high performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), cloud point (ASTM D2024-65) or water titration of an isopropyl alcohol solution. No solvents are necessary during the reaction, but inert solvents such as aromatic hydrocarbons (benzene and toluene) and ethers (ethyl ether) may be used to facilitate handling. In some instances it may be convenient to use a low mole ethoxylated acetylenic diol, since these products are liquids and are therefore easy to handle.
In reactions catalyzed by Lewis acids, the reaction conditions will be determined by the identity and concentration of the catalyst. Examples of Lewis acid catalysts include BCl3, AlCl3, TiCl4, BF3, SnCl4, ZnCl2 and the like. The preferred Lewis acid catalyst is BF3. In BF3 catalyzed reactions, temperature control during the initial stages of the reaction is critical, since too high a temperature will result in dehydration of the acetylenic diol. It is preferred that the temperature be maintained below 80° C., preferably below 60° C., and most preferably below 50° C. The reaction pressure can range from atmospheric to low to moderate superatmospheric pressure, i.e., from 15 to 300 psig (1 to 20 bar). Because of the high activity of BF3, good results can be obtained at more moderate pressures of about 1 bar than for those reactions performed using trialkylamine catalysts.
In adding liquid alkylene oxide(s) to the acetylenic glycol and the catalyst, care should be taken to avoid the presence of an excess of alkylene oxide(s) in the reaction mixture since the reaction is very exothermic and could prove to be very hazardous. The danger of an uncontrollable reaction can be avoided by adding the alkylene oxide(s) in a manner and at a rate such that the alkylene oxide(s) are reacted essentially as rapidly as they are introduced into the reaction mixture. The formation of a flammable mixture in the headspace is best avoided by pressuring the reactor headspace to a sufficient pressure with an inert gas such as nitrogen such that the alkylene oxide(s) remains below its lower explosive limit (LEL).
In the both the Lewis acid catalyzed and the trialkylamine catalyzed processes, the catalysts may be used at 0.001 to 10 wt %, preferably 0.01 to 5 wt %, and most preferably 0.1 to 1 wt %, based on total final reactant mass. In both cases, because deactivation may occur during the alkoxylation, it may be necessary to add additional catalyst to complete the reaction, particularly if large amounts of EO and PO are being added.
In the processes for making the randomly distributed EO/PO adducts, the EO and PO may be added to the reaction concurrently as separate charges or streams, or added as a single charge or stream comprising a mixture of EO and PO. In making block EO/PO adducts the EO and PO are added consecutively.
The alkoxylated acetylenic diols are useful for the reduction of equilibrium and dynamic surface tension in water-based compositions containing an organic compound, particularly aqueous coating, ink, fountain solution, agricultural and electronics processing compositions containing organic compounds such as polymeric resins, macromolecules, organic bases, herbicides, fungicides, insecticides or plant growth modifying agents. It is desirable that an aqueous solution of the alkoxylated acetylenic diol demonstrates a dynamic surface tension of less than 35 dynes/cm at a concentration of ≦0.5 wt % in water at 23° C. and 1 bubble/second according to the maximum-bubble-pressure method. The maximum-bubble-pressure method of measuring surface tension is described in Langmuir 1986, 2, 428-432, which is incorporated by reference.
In one aspect of the invention certain alkoxylated acetylenic diols of the above formula display excellent ability to reduce equilibrium and dynamic surface tension while producing substantially no foam. This behavior is particularly advantageous in photoresist developer formulations.
The alkoxylated acetylenic diols are suitable for use in an aqueous composition comprising in water an inorganic compound which is, for example, a mineral ore or a pigment or an organic compound which is a pigment, a polymerizable monomer, such as addition, condensation and vinyl monomers, an oligomeric resin, a polymeric resin, a macromolecule such as gum arabic or carboxymethyl cellulose, a detergent, a caustic cleaning agent, a dissolution agent such as tetramethylammonium hydroxide (TMAH), a herbicide, a fungicide, an insecticide, or a plant growth modifying agent.
An amount of the alkoxylated acetylenic diol compound that is effective to reduce the equilibrium and/or dynamic surface tension of the water-based, organic or inorganic compound-containing composition is added. Such effective amount may range from 0.001 to 10 g/100 mL, preferably 0.01 to 1 g/100 mL, and most preferably 0.05 to 0.5 g/100 mL of the aqueous composition. For water-based photoresist ceveloper/-electronics cleaning compositions effective amounts may range from 0.001 to 1 g/100 mL, preferably 0.002 to 0.8 g/100 mL, and most preferably 0.005 to 0.5 g/100 mL. Naturally, the most effective amount will depend on the particular application and the solubility of the particular alkoxylated acetylenic diol.
In the following water-based organic coating, ink, fountain solution and agricultural compositions containing an alkoxylated acetylenic diol according to the invention, the other listed components of such compositions are those materials well known to the workers in the relevant art.
A typical water-based protective or decorative organic coating composition to which the alkoxylated acetylenic diol surfactants of the invention may be added would comprise the following components in an aqueous medium at 30 to 80 wt % ingredients:
|Water-Based Organic Coating Composition |
|0 to 50 wt % ||Pigment Dispersant/Grind Resin |
|0 to 80 wt % ||Coloring Pigments/Extender Pigments/Anti-Corrosive |
| ||Pigments/Other Pigment Types |
|5 to 99.9 wt % ||Water-Borne/Water-Dispersible/Water-Soluble Resins |
|0 to 30 wt % ||Slip Additives/Antimicrobials/Processing Aids/ |
| ||Defoamers |
|0 to 50 wt % ||Coalescing or Other Solvents |
|0.01 to 10 wt % ||Surfactant/Wetting Agent/Flow and Leveling Agents |
|0.01 to 5 wt % ||Acetylenic Diol EO/PO Derivative |
A typical water-based ink composition to which the alkoxylated acetylenic diol surfactants of the invention may be added would comprise the following components in an aqueous medium at 20 to 60 wt % ingredients:
|Water-Based Ink Composition |
|1 to 50 wt % ||Pigment |
|0 to 50 wt % ||Pigment Dispersant/Grind Resin |
|0 to 50 wt % ||Clay base in appropriate resin solution vehicle |
|5 to 99.9 wt % ||Water-Borne/Water-Dispersible/Water-Soluble Resins |
|0 to 30 wt % ||Coalescing Solvents |
|0.01 to 10 wt % ||Surfactant/Wetting Agent |
|0.01 to 10 wt % ||Processing Aids/Defoamers/Solubilizing Agents |
|0.01 to 5 wt % ||Acetylenic Diol EO/PO Derivative |
A typical water-based agricultural composition to which the alkoxylated acetylenic diol surfactants of the invention may be added would comprise the following components in an aqueous medium at 0.1 to 80 wt % ingredients:
|Water-Based Agricultural Composition |
|0.1 to 50 wt % ||Insecticide, Herbicide or Plant Growth Modifying |
| ||Agent |
|0.01 to 10 wt % ||Surfactant |
|0 to 5 wt % ||Dyes |
|0 to 20 wt % ||Thickeners/Stabilizers/Co-surfactants/Gel |
| ||Inhibitors/Defoamers |
|0 to 25 wt % ||Antifreeze |
|0.01 to 50 wt % ||Acetylenic Diol EO/PO Derivative |
A typical fountain solution composition for planographic printing to which the alkoxylated acetylenic diol surfactants of the invention may be added would comprise the following components in an aqueous medium at 30 to 70 wt % ingredients:
|Fountain Solution for Planographic Printing |
|0.05 to 30 wt % ||Film formable, water soluble macromolecule |
|1 to 75 wt % ||Alcohol, glycol, or polyol with 2-12 carbon atoms, |
| ||water soluble or can be made to be water soluble |
|0.01 to 60 wt % ||Water soluble organic acid, inorganic acid, or a salt of |
| ||thereof |
|0.01 to 50 wt % ||Acetylenic Diol EO/PO Derivative |
Other compositions in which use of the acetylenic diol EO/PO adduct as a surfactant is particularly advantageous are the developers for photoresists that are employed in the semiconductor industry. Such developers and their use are well known in the art and do not need to be described in detail. In fact, as pointed out in the background section of this disclosure, the use of ethoxylated acetylenic diol adducts in such formulations is known and well documented. The improvement provided by this invention, which could not have been foreseen, involves the use in these developer formulations of certain acetylenic diol adducts which also contain propoxy groups.
A typical water-based photoresist developer, or electronic cleaning, composition to which the alkoxylated acetylenic diol surfactants of the invention may be added would comprise an aqueous medium containing the following components:
|Water-Based Photoresist Developer Composition |
| ||0.1 to 3 wt % ||Tetramethylammonium Hydroxide |
| ||0 to 4 wt % ||Phenolic Compound |
| ||10 to 10,000 ppm ||Acetylenic Diol EO/PO Derivative |
| || |
Briefly, the process for manufacture of integrated circuits involves the application of a film of photoresist composition to a suitable substrate, such as a silicon wafer, which is then exposed to actinic radiation in a designed pattern that is imposed upon the photoresist film. Depending upon whether the photoresist is positive or negative-working, the radiation either increases or decreases its solubility in a subsequently applied developer solution. Consequently, in a positive-working photoresist the areas masked from the radiation remain after development while the exposed areas are dissolved away. In the negative-working photoresist the opposite occurs. The surfactant of this invention can be used in developers for either type of photoresist. The character of the developer is very important in determining the quality of the circuits formed and precise control of developing is essential. To achieve better surface wetting by the developer is has been common to add surfactant to the formulation in order to reduce surface tension of the solution. This addition, however, can cause the developer to foam which leads to circuit defects. This foaming problem is also recognized in the art and considerable attention in the industry has been directed toward its solution.
The developer, or electronics cleaning, solutions in which use of the adduct of the invention is preferred are the aqueous solutions of tetramethylammonium hydroxide (TMAH). These developers are also well known in the art. Commercial developers usually contain low levels of surfactant on the order of 50 to 1000 ppm by weight. Surfactant level should not exceed that required to achieve the desired surface tension of the solution. For example, surface tensions of about 40 to 45 dynes/cm would be appropriate for novolac-based photoresist resins. Advanced resins that often incorporate aliphatic groups might require a developer with lower surface tension to enhance wetting. One of the advantages of the surfactants of this invention is that suitable surface tensions can be obtained at lower levels than is required by other wetting agents. This in itself is a step toward solving the foaming problem in the manufacture of microcircuitry.