CA1332093C - Photoimagable solder mask coating - Google Patents
Photoimagable solder mask coatingInfo
- Publication number
- CA1332093C CA1332093C CA000550900A CA550900A CA1332093C CA 1332093 C CA1332093 C CA 1332093C CA 000550900 A CA000550900 A CA 000550900A CA 550900 A CA550900 A CA 550900A CA 1332093 C CA1332093 C CA 1332093C
- Authority
- CA
- Canada
- Prior art keywords
- reaction mixture
- alpha
- diisocyanate
- carbon atoms
- acid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/025—Non-macromolecular photopolymerisable compounds having carbon-to-carbon triple bonds, e.g. acetylenic compounds
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/027—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds
- G03F7/032—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds with binders
- G03F7/035—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds with binders the binders being polyurethanes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F299/00—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers
- C08F299/02—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers from unsaturated polycondensates
- C08F299/06—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers from unsaturated polycondensates from polyurethanes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/34—Carboxylic acids; Esters thereof with monohydroxyl compounds
- C08G18/348—Hydroxycarboxylic acids
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/67—Unsaturated compounds having active hydrogen
- C08G18/671—Unsaturated compounds having only one group containing active hydrogen
- C08G18/672—Esters of acrylic or alkyl acrylic acid having only one group containing active hydrogen
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/67—Unsaturated compounds having active hydrogen
- C08G18/671—Unsaturated compounds having only one group containing active hydrogen
- C08G18/672—Esters of acrylic or alkyl acrylic acid having only one group containing active hydrogen
- C08G18/6725—Esters of acrylic or alkyl acrylic acid having only one group containing active hydrogen containing ester groups other than acrylate or alkylacrylate ester groups
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/26—Processing photosensitive materials; Apparatus therefor
- G03F7/38—Treatment before imagewise removal, e.g. prebaking
Landscapes
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Polyurethanes Or Polyureas (AREA)
- Macromonomer-Based Addition Polymer (AREA)
- Paints Or Removers (AREA)
Abstract
A PHOTOIMAGABLE SOLDER MASK COATING
Abstract of the Disclosure A UV sensitive coating composition is des-cribed which is a polymer prepared from a condensation reaction of a diisocyanate, a hydroxy alkyl (di or tri) (meth)acrylate and a carboxylic acid polyol. Optionally, a polyol and/or a dicarboxylic acid polyol can also be included as reactants. The coating polymer, thus pre-pared, can also be combined with binders and crosslinkers.
Abstract of the Disclosure A UV sensitive coating composition is des-cribed which is a polymer prepared from a condensation reaction of a diisocyanate, a hydroxy alkyl (di or tri) (meth)acrylate and a carboxylic acid polyol. Optionally, a polyol and/or a dicarboxylic acid polyol can also be included as reactants. The coating polymer, thus pre-pared, can also be combined with binders and crosslinkers.
Description
.~
- 1 - RMD-?929 A PHOTOIMAGABLE SOLDER Mi~SK COATING
' ~ "
5Backaround of the In~ention ~"r Field of the Invention '~
~; This invention relates to a photosensitive resin composition. More particula~ly, it relates to a photosensitive resin composition for forming a protec-, ,~. ~ , tive coating film having excellent characteristics which can be used either alone, to provide a photosensitive, t~acky coat; or it can be combined with a variety of ` other types of lngredlents such as a crosslinker to increase crossllnking density, a resin to remove tacki-ness, or even another photosensitive ingredient to increase sensitivity to light. The uses of the instant photosensitive coating material ehus includes photore-sist applications such as plating resist, etch resist and solder mask.
, .
Soldexing masks are used to produce printed ;~ wiring boards. ~he solder masks function is basically to prevent solder-ing bridges, to keep electric insula-tion between conductors thus prev~nting conduction be-tween solder areas and to prevent-the corrosion o~ a naked cop~er conductor. It is al$o desirable to have pho;toimagable solder masks which are able to retain an image which can be used as a blueprint on which the sol- ;
der is placed. Due to the desirability of increasing ~ , ` ~ t ~
wiring density, it is desirable to use a solder mask having preci~e resolution and extremely good electrical insulation properties. The instant photosensitive composition can provide these advantage~.
Known solder masks are described in U.S. Patent 4,499,163 which de~cribes a photosensitive resin composition containing urethane diacrylate or dimethacrylate, a linear polymeric compound having a glass transition temperature between about 40 and 150 C., and a sensitizer which generates free radicals in actinic light. The linear polymeric compound described includes the vinyl series linear polymers or copolymers such as, for example, polyers made from vinyl monomers including methyl methacrylate, butyl methacrylate, methyl styrene, vinyl toluene, and the like. The sensitizer for generating free radicals includes, for example, substituted and unsubstituted polynuclear quinones.
Another photocurable urethane acrylate resin composition ;
which also is described as being usable for permanent resists, can be found described in U.S. Patent 4,587,201. The composition therein described uses a urethane-acrylate resin ;~
which is composed of polybutadiene polymer. This resin is combined with a photo-polymerization initiator to form the ~-permanent resist material. `~
Most photoimagable solder masks, however, lack the ability of being developed in an aqueous solution. This necessitates the use of organic solvent developing solutions.
The use of such organic solvents has become undesirable due to the environmental regulations for solvent emissions control.
Another disadvantage found with solder masks that use ~ ;~
organic solvent developing solutions, is the continued ;~
sensitivity of the final product to organic solvents such as methylene chloride. In certain product applications, moreover, such susceptibility is undesirable.
X ~'"' 1332~
It ~s there~ore desirable to develop photo-imagable solder masks coatin~ compositlons whlch can be developed ln aqueous solutions, and which are resistant to organic solvents such as methylene chlorlde. It i8 an ob~ect oftthe instant lnventlon to provide such a coating composition. It ls al50 an ob~ect of the lnstant lnventlon to provide a solder mask coatin~ com-position which can be stripped with commercial alkaline :
strippers. Accordingly, the photosensltive resin como-slt~ons de~erlbed herein have excellent resolutlon, flexlbllity, adherance to metals, solvent resistance, hlgh temperature reslstance and electrlcal insulation properties.
Specific embod~ments of the lnstant composi- ~"
~5 tion provides a hl~hly viscous photosensitive material which ~s useful as an addltlve for composltions that require both thlckening and the additlon of a photosen-sltive coatlng material. In thls way, the lnstant pbo-tosensltive materials fulfill a dual role, both as a thickener and as a photosensltlve, photocurable addl-tlve. Such embodiments of the lnstant composltlons are thus useful photo~enslt~ve, photocurable thickenlng agents for material~ such as paints, lnks, etc.
Summarv of the Inventlon A photocurable coating composition lncludes a UV sensltive compound selected from: carboxylated urethane dlacryl~te, carboxylated urethane triacrylate, carboxylated urethane dlmethacrylate and carboxylated urethane trlmethacrylate. Thls group ls hereinafter referred to as carboxylated urethane di (and/or) i~ 1~ 1 , i .
tri(meth) acrylate. It is also understood that (meth)-acrylate is lntended hereln to mean acrylate and/or methacrylate.
These carboxylated urethane di and/or trl~meth)acrylates are prepared from acidified mo~eties which provlde the carboxyl group. These compositions are prepared by condensin~ a d~isocyanate, a carboxylic acld polyol, and a hydroxy alkyl (meth)acrylate.
.. .. . .
.. . . ~ , .
_ 4 _ 1332093 The carboxy]ic acid polyol should be present in an amount needed to provide at least about .3 milliequivalents of acid per gram of the combined arnount of the total amount of reactants; abbreviated herein as mel/g of TR (total reactants usually are the diisocyanate, carboxylic acid polyol, and hydroxyalkyl (meth)acrylate). In order to obtain a suitable level of photosensitivity in thisproduct, the hydroxyaLtcyl (meth)acrylate should be used in a minimum amount of about .5 milliequivalents per gram of the combined amount of the diisocyanate, carboxylate acid di- or triol and hydroxya1kyl (meth)acrylate.
The present invention, then, in one aspect, resides in a photoimagable coating composition comprising: a W sensitive polymer selected from the group consisting of: a carboxylated urethane dimethacrylate, a carboxylated urethane diacrylate, a carboxylated urethane triacrylate, and a carboxylated urethane trimethacrylate; said W sensitive polymer being made by condensing a reaction mixture comprising component (a) a diisocyanate having from 6 to 18 carbon atoms, component (b) a carboxylic acid polyol having the forrnula [OHl,~-R6-COOH; wherein x is an integer from 2 to 5, and wherein R~ is a linear or branched, saturated, unsaturated or aromatic, hydrocarbon moiety having from 2 to 29 carbon atoms, and component (c) a hydroxyaLtcyl (meth)acrylate wherein its a~yl has from 2 to 28 carbon atoms; provided that component (a) is present in an amount of from about 30 to about 80% by weight of the total amount of the reaction mixture; component (b) is present in an amount of from about 5 to about 45% by weight of the total amount of the reaction mixture with a minimum of about .3 millie~quivalents of acid per gram of the total amount of the reaction mixture, and component (c) is present in an amount of from about 5 to about 50% by weight of the total amount of the reaction mixture with a minimum amount of .5 milliequiYalents of acrylate p~r gram of the total amount of the reaction mixture.
l~e present invention, in another aspect, resides in a method for the preparation of a UV sensitive polymer comprising conducting a condensation reaction with a reaction mixture comprising: component (a) a diisocyanate havingfrom 6 to 18 carbon atoms, and component (b) a carboxylic acid polyol having ,''''~
.'~
- 4a - 1332033 the formula [OH~ COOH; wherein x is an integer from 2 to 5, and wherein R6 is a linear or branched, saturated, unsaturated or aromatic, hydrocarbon moiety having from 2 to 29 carbon atoms, and component (c) a hydroxyalkyl (meth)acrylate wherein its alkyl has from 2 to 28 carbon atoms; provided that S component (a) is present in an amount of from about 30 to about 80% by weight of the total amount of the reaction mixture; component (b) is present in an a nount of from about 5 to about 45% by weight of the total amount of the reaction mixture with a minimum of about .3 milliequivalents of acid per gram of the total amount of the reaction n~Lxture, and component (c) is present in anamount of from about 5 to about 50% by weight of the total amount of the reaction mixture with a minimum amount of .5 milliequivalents of acrylate per gram of the total amount of the reaction mixture.
The instant invention includes a variety of embodiments, achieved by combining the above coating composition with other specifically selected ingredients. Such ingredients, selected in order to provide or enhance a specific quality or characteristic, includes: a binder, a crosslin~ng agent, dyes, pigments, thermopolymerization inhibitors, and additives designed to improve coating properties.
Detailed Desc~tion The instant photocurable coating composition contains the carboxyl moiety, which alters the organophilic nature of the urethane (meth)acrylate polymer. As a result, the instant coating compositions become more organophobic, and thus are resistant to organic solvents such as methylene chloride. Further, these carboxylated photosensitive polymers can be mixed in large amounts with other hydrophilic binders and crosslinkers. In addition to this, ~e introduction of the carboxyl moie~ makes the instant coating compositions soluble or swellable in aqueous alkali solutions (pH in excess of 7.5) until exposure to W light. Advantageously, when the instant compositions are used to provide a photocurable coating, or solder mask, the development step can be done in aqueous alkali solutions. It can be noted that although the inco~poration of the carboxyl moeity changes the nature of the urethane (meth)acrylate, making ,, ~
4b 1332093 it soluble in aqu~ous .~,,~ ,,.
`'"
~ , : ., .
~, '~', ; ~ . ;', `
,, ; .
, . :
~.
, ~ 13 3 2 0 9 3 alkali, the sensitivity of the compound to UV light is retained. The carboxylation, moreover, improves adherance to metals. Thus, an improved solder mask is provided by ~he combination of a binder, a crosslinker, and a carboxylated urethane di (and/or) tri(meth~-acrylate. A preferred combination would use a copolymer of styrene/maleic anhydride as the binder (also provid-ing carboxyl groups). Preferred crosslinkers are the (meth~acrylate, and polyfunctional (meth)acrylate ~ono-mers.
Preferred carboxylated urethane di (and/or)tri(meth)aerylates of the instant inventlon can be represented by the following formula:
FormLla 1 Rl H ~ H ~ H H Rl CH=C-lCOR20C~NR3NC(OtR40~NR3NCO]~R50jNR3NC)nOR20CC=CH
O O O O O O O O
wherein n is an integer from 1 to 4; k can be either 0 or 1; and wherein Rl, derived from the acrylate reaction component (c) can be either a hydrogen or a methyl group; R2, also derived from the alkyl (meth)acrylate reaction component (c), can be a linear or branched saturated hydrocarbon moiety having from 2 to 28 carbon atoms; R3 is derived from the diisocyanate portion of the reaction mixture. R3 can be branched, linear or cyclic, saturated, unsaturated or aromatic hydrocarbon moiety. R3 can acceptably have from 4 to 20 carbon atoms, and preferably, has from 6 to 18 carbon atoms. For other preferred embodiments R3 is derived from the diisocyanate reactant selected from trimethyl-hexamethylene, hexamethylene, isophorone, tolylene,~
4,4,methylenebis(cyclohexyl), methylenediphenyl, and tetra methylxylene diisocyanates. R4 is a linear, cyclic or branched, aromatic, saturated or unsaturated hydrocarbon acceptably having from 2 to 28 carbon atoms. R4 can optionally also contain a hydroxyl moiety (remaining from the polyol used in the preparation of the composi-. f~ :
~. ! ~j ~
- 6 - RMD-7g29 1 133~0~
tion). R5 will be derived from a reaction mixture including (a) the carboxylîc acid polyol shown in and described for Formula 2; or ~b) the carboxylic acid ;:
polyol of Formula 2 and from the hydroxyl dicarboxylic acid shown in and described for Formula 3. Thus, R5 will always have at least one COOH moiety and will have a minimum of 3 carbon atoms. When R5 is derived from ta) (from Formula 2 compounds only) it will have only one -COOH group with a branched or linear; saturated, unsa-lo turated, or aromatic, acceptably, having a total of from 3 to 30 carbon atoms including the carboxyl carbon atom.
When R5 is derived from -(b) the overall composition will have R5 moleties derived from the carboxylic acid polyol -of Formula 2 and also F~5 moieties derived from the hydroxyl dicarboxylic acids of Formula 3. The R5 moie~
ties derived from the Formula 3 hydroxyl dicarboxylic ~i acid compounds will, ob~iously, have two COOH groups and ~ `
can also have from 3 to 30 carbon atoms, including the :
two carboxyl carbons. The descriptions given herein for ~-the Formula 2 and Formula 3 compounds will provide more information regarding the concentrations and preferred ~:~
structures of these R5 mo~eties.
It should be realized that the exact location '~
of each R5 moiety within the polymer molecule will depend upon the number of reactive hydroxyl groups of the Formula 2 or Formula 3 compound, and upon the somewhat random condensation reaction. For example, when R5 is derived from b) and when y of Formula 3 is one, R5 will be a terminal group having two COOH moieties; simultane-ously other R5 moieties from the same reaction mixture,~derived from the Formula 2 carboxylic acid polyol) will be randomly located within the backbone of the polymeric ;~
molecular structure as indicated above in Formula 1. .
In Form~la 1, the R2 preferably has from 2 to 16 carbon atoms, or, more preferably, is a moiety selected from the group consisting of: ethyl, propyl, - `
butyl, and: 1l ~ ;
(CH2 ~ C ~O(CH2)s C~m where m - 1 or 2.
~ . . :,.:,' .
1332~9~ RMD-7929 R4 ls derived from the optional polyol which can be added to the reaction mixture. R4 will, there-fore, have from 2 to 28 carbon atoms and from 2 to 5 oxygen atoms. The oxygen ato~s can possibly be in an unreacted hydroxyl moiety. When R4 i8 present, acceptably, it has from 2 to 28 carbon atoms or, R4 has, preferably, from 2 to 16 carbon atoms; still optionally having a hydroxyl moiety. Other preferred embodiments allow R4 to be a saturated or unsaturated hydrocarbon moiety havlng from 2 to 10 carbon atoms and from 2 to 5 oxygen atoms possibly as an unreacted hydroxyl group.
In specific examples of such preferred embodiments, R4 is a moiety selected from: ethyl, propyl, butyl, pen-tyl, hexyl, heptyl, and octyl and having from 2 to 5 oxygen atoms from the previous hydroxyl ~oieties. R
can also be derived from glyceryl or 2-ethyl-2-(hydro-xymethyl)-1,3propylene.
The carboxylated urethane d~ (and/or) tri(meth)-acrylates of the instant invent~on can be obtained by condensing a diisocyanate with a carboxylic polyol (see Formula 2) and a hydroxyalkyl(meth)acrylate in a one step reaction. The carboxyl-containing polyol can be any -~
carboxylic acid containing 2 or more hydroxyl moieties.
Sultably, there are from 2 to 5 hydroxyl groups.
Preferably, the carboxyl-containing polyol is either ~-a carboxylic acid diol or triol.
Suitably, therefore, the carboxylic acid polyol can have the formula shown in FoLmula 2 as follows:
FormNla 2 ~ HO ] X-R6-COOH
wherein x is an integer from 2 to 5 and R6 is a branched, cyclie or linear, saturated, unsaturated, or aromatic hydrocarbon moiety having from 2 to 29 carbon atoms. Preferably, R6 has from 2 to 24 carbon atoms while x is 2 or 3 Isuch as in a diol or triol). Most preferably, x is 2 and ~6 is a branched or linear; ~
~ saturated, unsaturated, or aromatic, hydrocarbon struc- ~-L~ ture with from 2 to 20 carbon atoms. A preferred embod- ~
~L , ~
iment uses an alpha- alpha dimethylol alkanoic acid as the ~
--8- 1 3 3 2 ~ ~ 3 !
carboxylated diol, most preferably, having an alkyl group having from 1 to 8 carbon atoms. Other preferred diol carboxylic acids are selected from: alpha-alpha-dimethylol acetic acid; alpha-alpha-dimethylol propionic acid, alpha-alpha-dimethylol butyric acid, alpha-alpha diethylol acetic acid; alpha-alpha diethylol propionic acid; alpha-alpha dipropylol propionic acid; alpha-alpha dipropylol butyric acid, and 2,3-dihydroxyl propanoic acid.
Optionally, a polyol can be additionally included in the reaction mixture. This will increase the molecular weight of the instant product. The presence of the polyol results in materials as depicted under Formula 1 wherein K = 1.
One embodiment of the instant invention can preferably be taken advantage of when a higher concentration of hydroxyl groups are provided, (such as by the addition of a polyol or by the use of a carboxylic acid as shown in Formula 2 where x is 3, 4, or 5). In this embodiment, a hydroxyl dicarboxylic acid is added to the reaction mixture. Formula 3 below shows a formula for some suitable hydroxyl carboxylic acids: ;
Formula 3 [HO]y~R7~(COOH)2 :-~
where y could be from 1 to 5, (preferably being from 1 to 3) and R7 is a linear, cyclic, or branched; saturated, unsaturated, or aromatic hydrocarbon moiety acceptably having from 1 to 28 carbon atoms; preferably, having from 1 to 18 and most preferably, from 1 to 12 carbon atoms. If y is from 2 to 5, R7 preferably ranges from 2 to 18 carbon atoms. Preferably, these diacids should be used when the hydroxyl concentration of the total reaction mixture is at least about .3 -~
milliequivalents of OH per gram of the combined amount of the reactants, (the diisocyanate, the carboxylic acid polyol, the hydroxyl alkyl(meth)acrylate, the hydroxyl dicarboxylic acid and the polyol if present). These diacids can suitably be used in an amount of from about .3 to about .7 milli-equivalents of acid per gram of the combined amount of the reactants. Some sultable hydroxy dicarboxylic acids can be selected from the group consistlng of; malic aoid, tartaric acld, dihydroxy tartaric acid, hydroxy adipie a~it, dihydroxy adlpic acid, and trihydroxy adipic acid.
~ hese dicarboxylic acids can b~ used to pro-vide thermally curable pendent or terminal ends. Advan-tageously, these ends can also provide reactive sites for future reaction with other materials. Melamine and epoxy for example are two compounds or moieties that can be reacted with the ter~inal carboxyl groups. By such reactions the characteristics of the material can be further ~odified or enhanced. The specific characteris-tics or qualitles des~red will depend on the intendeduse of the material.
To prepare the instant carboxylated urethane di (and/or) tri(meth)acrylate coating composition, the -reaction is carried out in a dry solvent solution which itself is non-reactive to the diisocyanate. Suitable examples of such solvents are ester6 like ethyl acetate and propylene glycol monomethyl ether acetate; ketones like methyl ethyl-ketone, ~ethyl isobutyl ketone, and N-methylpyrrol~done; aromatic hydrocarbons like toluene, xylene; and mixtures o~ the preceding.
The reaction preparing the instant coatlng compos~tion acceptably is conducted with the sol$ds content of the solution in the range of from about 20 to about 100%, preferably in the range of from about 35 to 95% and, most preferably, from about 65 to about 85%
by weight. The reaction temperature is generally from about 50 to about 95C., and preferably from about 6 to 85C. Preferably, homopolymerlzation is inhibited by the add$tion o~ a free radical polymeri~ation inhibitor such as hydroquinone, m-dinitrobenzene, Pheno-thiazine, and the like. Most preferably, they are used in an amount of from about 0.005X to about 1% by weight based on the weight of the solids.
' 1332~3 ~ - 10 - RMD-7929 . .
It is also preferred to use a condensation catalyst such as tin or amine catalysts. Such catalysts can be selected from the group consist~ng of: di-butyl tin dilaurate, dimethyl tin dineodecanoate, dibutyltin bisoctylthioglycolate, triethylamine, and triethylene diamine. For best results, the react~on is carried out under a dry air blanket.
The dilsQcyanate can be a hydrocarbon that is branched, l~near, or cyclic, saturated, unsaturated or aromatic. Acceptably, ~t has ~ro~ 4 to 20 carbon atoms, preferably, it has from 6 to 18 carbon atoms.
D~lsocyanates can be selected from the group consisting of: xylylene diisocyanate; 1-isocyanato-3-isocyanato-methyl-3,5,5-trimethylryclohexane; 3,3'-dimethyldiphenyl-~5 methane-4,4'-diisocyanate; 2,4,tolylenedlisocyanate;
2,6-tolylenediisocyanate; 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate:
methylene-bist4-cyclohexylisocyanate); hexamethylene-diisocyanate; ~eta-tetramethylxylenediisocyanate; para-tetramethylxylenedil ocyanate; ~ethylene-bis-phenyl-diisocyanate; 1,5-naphthylene diisocyanate; metaphenyl-lene diisocyanate and mixtures of the above. The most preferred diisocyanates are: 2,6-tolylenediisocyanate;
2,4,tolylene-diisocyanate, 1-isocyanato-3-isocyanato-methyl-3,5,5 trimethylcyclohexane; 2,2,4-trimethylhexa-methylene-diisocyanate, and 2,4,4,trimethylhexamethylene d~isocyanate.
When a polyol is lncluded, the ~olecular weight, cure speed, and crosslinking density will be increased. The polyol can have from 2 - 28 carbon atoms. Acceptably, the hydrocarbon portion can be branched or linear, saturated, unsaturated, or aroma~ -tic, and has from 2 - 5 hydrcxyl moieties. Preferably, the polyol is a diol or triol having from 2 to 16 carbon atoms. Preferred diols can be selected from: ethyle-ne glycol, propylene glycol, butanediol, Pentanediol, hexanediol, octanediol, neopentylglycol, 2-methylpro- ~i pane-l, 3-diol, cyclohexanedimethanol, and diethylene ;~ ' :
'' : , .
1332~
RMD-~929 glycol. Other preferred polyols include glycerol, tri-methylolpropane, or hexanetrlol which can also be used.
The hydroxyalkyl (meth)acrylate (Component C) can have an alkyl ~roup with from about 2 to 28 carbon atoms. The alkyl molety can also be llnear, cyclic, or branched, saturated or unsaturated. Prefer-ably, the alkyl ~roup of the hydroxylalkyl(meth)acrylate has from 2 to 12 carbon atoms. Some preferred hydroxy-alkyl (meth)acrylates can be selected from: hydroxyethyl-(meth)acrylate, hydroxypropyl~ (meth)acrylate, hydroxy-butyl (meth)acrylate, and compounds having the general formula:
O O o ,~
~: 11 p U
CH2'CH-C-O~C(CH2)50~mClCH2)50 where m is one or two.
When the instant coating composition is pre-pared, the concentratlons of the reactants should be such that the total concentratlon of the hydroxyl groups ls at lea~t approximately equal to the amount of dlisocyanate present. Broadly, this means that the concentratlon of the polyols, plus the dlols of the ~-dialkylol carboxylic acid, plus the hydroxyalkyl (meth)-acrylate is sufficient to brlng the ratio of the hydroxyl to the diisocyanate ,to at least about .95:1, and, pre-ferably, to at least 1:1. Most preferably, the hydroxyl moiety has the excess of equivalents. Preferably, the hydroxyl should have an excess eguivalents relative to -~
the dlisocyanate ln the range of from about 1.05:1 to about .95:1; most preferably, lt is in the range of from 1.02:1 to about 1:1. -`~
~I j The carboxylic acld polyol ls an important ; $ngredient of the instant coatlng composition, and is ;~
preferably present in an amount sufficient to allow the ;~
~ uncured copolymer to be soluble or swellable in aqueous -~
;~ 35 alkali solutions. Suitably, the carboxylic acid polyol is present ln a mlnimum amount of about .3 milliequiva-lents of acid/gram of the total amount of the reactants; ~ ~
preferably, in an a~ount equal to or greater than .5 ~;
milliequivalents of acid per gram of the total amount of reactants. -;
~ ~ 332093 Polar solubility is even more enhanced when the carboxylic acid polyol is used in the reaction mixture in an amount greater than .8 acid milliequivalents per gram of the total amount of the reactants (meq/g of TR).
A preferred range of acid meq/g of TR is from about .8 to 1.6 acid meq/g of TR. If a highly viscous product, extremely suitable for combination with other materials is desired, it is most preferred that the reacti~n mixture contains a minimum amount of about 1 acid meq/g of TR; a most preferxed range is from about 1 to about 1.6 acid meq/g of TR. The use of the diacid of Formula 3 can also be used to add to the amount of acid milliequivalents.
Another advantage provided by the carboxylation of the urethane di and tri(meth)acrylates is that the W sensitive compound can be combined with hydrophilic resins.
Furthermore, by varying the concentration of the carboxylation in the urethane di and tri(meth)acrylates, the hydrophilic nature of this W sensitive compound can, to an extent, be controlled. This allows the hydrophilic character to be set for a specific resin. Thus, when one desires to use a more hydrophobic or less hydrophilic resin, a low concentration of carboxylation can be used in the urethane di and tri(meth)acrylate, to increase compatibility with the selected resin. Conversely, if one desires to use a hydrophilic resin, the carboxyl concentration would be increased so that the resin and the urethane di and tri(meth) acrylate could be i~
mixed in larger concentrations. Acceptably, the carboxylic acid polyol can be used in the reaction mixture in concentrations having the carboxylated polyol in an amount of from about 5 to about 45% by weight of the total amount of reactants (abbreviated as: by weight of TR), preferably, from about 5 to about 25~ by weight of TR, most preferably, from about 12 to about 25~ by weight of TR.
Y ::
it~ :
` - 13 - 1332~93 RMD-7929 When a specific polyol is also included,l it can be used in the reaction mixture in an a~ount of from about 2 to about 18% by weight of TR; and pre-ferably, having from about 2 to about 15% by weight of S TR. ~ ,.
i For the diisocyanate, an acceptable concen- ~:~
tration range is from about 30 to about 80% by weight of the TR. Preferably, it is in the range of from about , 50 to 75% by weight of TR. ~-The hydroxyalkyl(meth)acrylate must be pre~
sent in the reaction mixture in a minimum amount of i-about 0.50 meq of acrylate/g of TR to assure suitable VV .
sensltivity. A suitable range is from about .5 to about ~; 1.6 meq of acrylate/g of TR. An acceptable weight per-cent range is in an amount of from about 5 to about 50 by weight of TR and, preferably, it is used in an amount ~
of from about 10 to about 30% by weight of TR. ~;,.
The instant carboxylated urethane di ~and/or) i}~, tri~meth)acrylate copolymer coating composition can ~
acceptably have a weight average molecular weight of ,,3'~.
from about 500 to about 6,500, preferably, from about ;~
800 to about 3,000, and, most preferably, from about 1,000 to about 2,500 (determined by the Gel Permeation Chromatogsaph and based on a standard polystyrene cali~
bration curve).
In one preferred embodiment, the instant coat- ~
ing composition is combined with a binder. The resin -, which ls used for this preferably, should have a glass transition temperature (Tg) of about 155C. or greater, and most preferably is hydrophilic. The hlgh (Tg) will h,~
~ improve temperature resistance. Several commercially `i available resins can be used. Compatible mixtures can be achleved with the instant carboxylated urethane di (and~or) tri(meth)acrylates especially by advantageously varying the carboxyl concentration. Acceptable resins that can be used for this purpose are styrene/maleic anhydride copolymersi, particularly those which have been partlally esiterified wlth low molecular weight :"
: . .
~ ....
. ~, . - . ~
~ 14 - 13~2093 ~MD-7929 alcohols. Copolymers of styrene/maleic anhydride are eommercially avallable which have been esterified wlth m~xtures of alcohols from methyl to butyl. Such copoly-mers are commerclally available ln a wlde range Or mole-cular weights,. Acceptably, the molecular we~ght of this resin-binder should be in the range of from about 25,000 to about 300,000; and, most preSerably, from about 60,000 to about 250,000. Preferably, the copoly-mer used has a ratio of styr-ne to maleic anhydride in the range of ~rom about 1:1 to about 2:1. A preferred (Tg~ range for the binder is from about 155-C. to about 200-C.
Acceptably, the binder can be used in an amount of from about 85 to about 25X by weight of the total compositi-on, and, preferably, from about 1~ to about 60% by weight of the total composition.
Preferably, the carboxylated urethane di land~or) tri(meth)acrylate coating composition is mixed with the -~
- binder 80 that the glass transition temperature (Tg) of the end product is from about ?0 to about l90-C.
Preferably, the blnder acid number is from about 120 to about 280 mg of KOH/g of the blnder. Other polymers having the above described molecular weight, Tg, and acid number can also be used as a b$nder with the instant carboxylated urethane di (and/or) tri(meth)-acrylate coating composition. Suitable polymers for use ~
as binders include: methylmethacrylate-comethacrylic ~ -acld and methylmethacrylate-methylacrylate methacrylic acid.
~;~ 30 When the lnstant carboxylated urethane di ~-(and/or) tri(meth)acrylate ls used with other materials such as the above described binders, or other additives which can permissively be added such as crosslinkers, ;;~
dyes, solvents, pigments, photoinitiators, thermal inhibltors, the concentration of the UV sensitive car-boxylated coating ingredient should be in the range of from about 10 to about 85X by weight of th~ total com-bined composition. Preferably, it is in the range of ~r ~
~; ., from about 15 to about 75% and, most preferably, it is in the range of from about 17 to about 60% by weight of the total combined composition.
Preferred crosslinkers are the (meth)acrylate ~onomers. Crosslln~ers are used when lt ls deslrable to obtain a compositlon havin~ a greater crosslinking density, wh~ch in turn improves resistance to solvents such as methylene chloride. More preferred, are poly-functional ~meth)acrylate monomers. Such polyfunctional monomers can be selected ~rom: trimethylolpropanetri- ~
(meth)acrylate,trimethylolpropaneethoxylated tri(meth)- ;
acrylate, dipentaerythrltolhydroxypentaacrylate, and ditrimethylolpropanetetraacrylate.
Other crosslinkers which can be used can be selected fro~ th~ ~roup consisting of: divinyl ethers, acrylated epoxies, epoxy resins, and aminoplast reslns.
The acrylated epoxies are preferred since they lmprove ;~
overall heat resistance, solvent resistance, and overall adhes~on.
When the instant carboxylated coating compo-sition is used as a solder mask, the composition is `~
coated on an appropriate substrate, and dried to a tack free conditio~. The coated substrate is then photo~
i~aged with from about ?5-to 105 mJ/sg. cm. of UV
radiation, and then can be developed with an aqueoùs ~
a~kali solutlon. Preferably, the aqueous alkali so~u- `-tion is potassium or sodium carbonate. Generally, the` :
photoimaged coated substrate is inspected at this point.
When the instant coating composition is used, it is advantageous in that, $f desired, a coating can ~-be easily stripped with an aqueous alkaline stripper, and redone. The amount of al~ali needed in the strip-ping or developing solution ls very low. A solution which is lX by weight of the a base can be used. When the desired quality of an image i~ obtained, the instant coating can be given a post UV cure of 3 - 5 3/sq. cm.
This i5 followed by a heat cure, preferably, at 150C.
.. :
~,.
for a sufficient curing time. The instant compositions -ha~e excellent resolution, flexibility, and adherance to metals. -The instant inventlon can also be readily ~
understood from the examples that follow. It should be ~:
understood, however, that these examples are offered to illustrate the instant invention, and thus, they should not be used to limit it. All parts and percentages are '',"',;r by weight unless otherwise indicated.
Exam~le 1 The following example illustrates a prepara~
tion for the photoimagable coating composition.
~he following ingredients were added to a 5 ; liter round-bottomed flask, fitted with a mechanical P~.:
stirrer, a thermometer, a condenser, a gas inlet, and a ~.
heating mantle: 236.0 grams ~g), (about 4 equivalents), of 1,6-hexanediol; 268.0 g. tabout 4 equivalents) of di-methylolpropionic acid; 951.2 g. (about 8.2 equivalents) ; of 2-hydroxyethylacrylate; 0.23514 g. of phenothiazine is as a free radical inhibitor: ~83.8 g. of N-methyl-2- ;~
pyrrolidone as a solvent; and 31.35 g. of dibutyltin~
dilaurate ~T-12) as a catalyst. Under a dry-air blanket with agitation, 1,680.0 g. (about 16 equivalents) of tri-methylhexamethylenediisocyanate was charged into the mixture in two equal portions which were 30 minutes apart. An exotherm took place for each addition. The reaction temperature was kept under 85C. by cooling -~;
with an ice-water bath, and after the second addition of trimethylhexamethylenediisocyanate the reaction tem-perature was maintained at a constant 85C. for 10-12 ~
hours until the isocyanate infra-red absorption peak ;:~-had disappeared, which indicated that the reaction had ~-i ~ gone to completion.
: Exam~le 2 The photosensitive coating compos~tion which was prepared in Example 1 was used to prepare a photo-i~aga~le solder mas~. The solder mask was prepared by charging the following ingredients to a 500 ml. round-, . .
.. , ~ 1 3 3 2 o 9 3 RMD-7929 bottom flask, equipped with a stirrer, a gas inlet!, a thermometer, and a condenser: 6.5 g. of a low mole-¢ular weight copolymeric defoaming ~gent; 91.25 g. of N-methyl-2-pyrrolidone as a solvent; 82.0 g. of an esterified styrene/maleic anhydride copolymer was added as a binder. (The resin used here was"Scripset 550"by Monsanto). The mixture was agitated and heated to 95~C. ~or 30 minutes to obtain a hazy solution. After ' this, the temperature was lowered to 70C., and then the following ingredlents were added to the mixture:
0.004 g. of the free radical polymerization inhibitor, phenothiazine; ~.S g. of the UV sensitive coating com-position prepared ln Example 1, and 9.0 g. of a green pigment. While the'mixture was blanketed with a flow of dry air, a premix~d solution containing the follow-ing was added: 47.8 g. of trimethylolpropanetriacrylate (SR351) as a crosslinker, 6.5 g. of 1sopropylthioxan-thone (abbreviated as ITX) as a photoinitiator and 8.4 g. of ethyl p-dimethylaminobenzoate (abbreviated as EPD) as a sensitizer. ' The above insredients were allowed to mix under a dry alr b!anket for 30 minutes at ~0C., after which time they were discharged into an amber ~ar. The solder mask thus prepared was used as described in .-Example 3. '' Exam~le 3 The comp'os-ition prepared in ~xample 2 was applied as a coating to two 6" x 8" bare copper clad epoxy boards in a thickness of about two mils, using a 75 mesh monofilament polyester screen, and a rubber squeegee having ~0 durometer hardness. This wet coat-ing was dried to a 1.4 mil tack-free film in a forced-air oven at 100C. in a period of 12 minutes.
- After these dried films were cooled to room temperature, they wer~ exposed at 75 m~/sq. cm. through an IPC (Institute for Interconnecting Packaging elec-tronic circuit~) No. B-25 negative artwork with 400 watt mercury vapor Iamp. The exposed films were then * Trademark .. . . .. .
: ** Trade~ark '' ., ... .: , .
.
- 18 - 3 2 0 ~3 RMD-~929 developed manually in a 1% solutio~ of K2C03 for 45 seconds, and then rinsed with fresh water. .~-An excellent resolution of the IPC B-25 was produced.
After this development, the boards were cured , at 3 J/sq. cm., and thermal baked at 150'C. for one hour -.
as a post-cure process. -~
One of the boards was then soaked in methy-lene chloride (abbreviated MeCl2) for 15 minutes, and no degradation was found on the mask (solvent resistance test). ,.
The other board was given a cross-hatch adhe-sion test according to ASTM D3359-78 method B, and was found to have no adhesion loss. The board waR then ~.
painted with a resin flux, and floated with the face having the solder mask down on a molten solder pot at 260-275C. for 10 seconds. After the solder pot test, the board was immediately rinsed with l,1,1-trichloro-ethane while the board was s~ill warm. One hour later, the board was given the same cross-hatch adhesio~ t~6t and found to have no adhesion 105s.
Exam~le 4 ,~!`.
Using the apparatus and general procedure as described in Example 1, urethane diacrylate oligomers were prepared which varied in the amount of car-boxylatlon. Sample 4 contained no carboxylation and Sample 9 contained the highes~ amount of carboxylation.
All of the samples were prepared at 80X solids. The formulation used for each individual sample is shown in .~
Table 1 below. ~;
Table 1 The following abbreviations have been employed.
DMPA = dimethylolpropionic acid 2HEA = 2-hydroxyethyl acrylate TMDI = trimethylhexamethylene diisocyanate DTN = dimethyl tin dineodecanoate M-Pyrol - N-methylpyrrolidone .
eq. = equivalent . - 19 - - RMD-~929 Sam~le 4 Sam~le 5 ¦ eq. Welaht eq. Welaht (g~s) ~gmsl 1,6 Hexanediol 8 472 7.0413.0 DMPA - - 1.0 67.0 2HEA 8.1939.6 8.2951.2 ~MD~ 161680.0 16.01680.0 DTN - 15.46 -15.56 M-Pyrol - ~2.9 -~77.8 Phenothiazine - 0.309 -0.311 SamDle 6 Sample ~ ~`
¦ ea. Weiaht eg. Welcht :~
: ~gms) (gms) 1,6 Hexanediol 3.01~7.0 2.0118.0 `~
DMPA 5.0335.0 6.0402.0 2HEA 8.2951.2 8.2951.2 :~ TMD~ 16.01680.0 16.01680.0 DTN - 15.~2 -15.76 M-Pyrol - 785.8 -762.8 :~
Phenothiazine - 0.314 -0.315 Sam~ie 8 Sam~le 9 e~. Weiqht ~ Wei~ht (gms) (gms) 1,6 Hexanedlol 1.0 59.0 0 0 DMPA ~.0469.0 8.0536.0 2HEA 8.2951.2 8.2951.8 .:
TMDI 16.01680.0 16.01680.0 DTN . - 15.8 -31.67;
~ '~ M-Pyrol - 789.8 -791.8 :~
-~ 30 Phenothiazine - 0.316 -0.31~
i The viscosities of Samples 4 - 9 were measured ~: (in C~S) at ~5-F; using a"Brookfield RVT Viscometer, #6 spindle at 10 RPM. ;~
: Sample # 4 5 6 ~ 8 9 Viscosity 20400 2240~)41600 44800 68800 86gO0 : ~ ~ ` ' '''''.;'~ '"
' .-~ ' .
* Trademark `~`` - - 20 - 133~93 RMD-~929 ~xamPle 5 Samples 5-9 of the carboxylated urethane acry- -lates were used to prepare solder masks. These solder ~:
masks were then tested for comparison of properties.
This example, alon~ with examples 6 and 7 which follow, can be used to compare the properties of the carboxylated urethane acrylates to masks containing the noncarboxylated urethane acrylates. !~
The solder masks designated herein as Example ~-lo D - H were prepared using the apparatus and general pro- ~-cedure as described in Example 2.
The amount of each ingredient is given in the ti following table: ~-Table 2 A Common Solder Mask Formula for Sam~les D - H
" Modaflo~'(a low molecular weight copolymer)- 6.5 N-methyl pyrrolidone -91.25 Styrene~maleic anhydride ~'Scripset 55d)** 82.0 Phenothiazine 0.00~ ;:
.
Carboxylated Urethane Acrylate ~.5 Green Pi~ment ~9G5) 9.0 Isopropyl Thioxanthone 6.5 Ethyl p-dimethylamino benzoate 8.4 Trimethylolpropyl triacrylate (SR351)*** 4~.8 Summarv of Pro~erties of Solder_Masks ,. .
Contalnin~ Carboxvlation Solder Mask (Sam~le-No.) D E F G H
Carboxvlated Urethane 5 6 7 8 9 :
Using the solder masks of Samples D-H, bare, 30 copper clad epoxy boards were coated using the general 1.
method as described in Example 3. The boards were then tested and evaluated.
Photos~eed - was excellent at ~5 m~/cm2 for Samples D-H.
Develo~ment: For Samples D-H in a 1% aqueous K2C03 35 solution for samples was excellent.
In 1,1,1 trichloroethane development for Sample D-H was poor.
* Trademark ** Trademark *** Trademark :; '' " , : .
Adhesion Test Method: ASTM-D3359-78 Method B , , (Scale 5 = No adhesion loss) . ;
~Scale 0 = Complete adhesion loss) _.
Sample Number D E F G H i S Adhesion before molten solder 5 4-5 4-5 5 4-5 ..
.~.dhesion aft~`- molden solder was applied 5 5 5 5 5 ~/~
Exam~le 6 .
Sample~ of a solder mask composition, using the Sample 4 no~carboxyla~ed material, was prepared as follows described in Example 2. -The in~redient~ and amounts of the ingredients are given in the following table: ..
Table 3 ~, Solder Mask Solder Mask Formulation Sam~le A SamPle B ;
(Defoamer) 1.10 1.30 .
N-methylpyrrolidone 41.8 50.35 Scripset 550 30.68 36.50 Phenothiazine 0.0024 0.003 : Green Pigment (9G5) 3.1 3.1 Sample 4 29.0 ~5.0 `
SR351 16.2 ---Isopropyl Thioxanthone 2.25 3.0 EPD 3.1 4.0 To provide a comparison using the procedures ~:: as described in Example 3 each of these formulations ~ .
A&B) were tested and used to coat a bare copper clad epoxy board which was ~urther characterized. The :
~: ` 3~ results are given below~
: Solder Mask Solder Mask SamPle A Sam~le B
Limited Compatibility Total Phase Separation :
~: Sta~lity at 75F 1 month ~: 35 De~elo~ment 1% aq. K2C03 excellent ---1,1,1, trichloroethane poor ---~ 22 - ~3~093 RMD-792g Pro~ertv . ~.
Methylene Chloride Resistance was,,poor showing the ~,i solvent's effect after only a 2 min. exposure.
Adhesion before molt~n.solder* , 5 l,, after molten solder~ 5 ,, SR351 = Trimethylolpropane triacrylate ITX = Isopropyl thioxanthone EPD z ~thyl p-dlmethylamino benzoate ':
* crosshatch adhesion - ASTM-D3359-78 Method B .
. Scale 5 = no adhesion loss Scale 0 - complete adhesion loss ~xam~le 7 Also for the purposes of comparison, Sample 4ii "~ .
material was used to prepare a photosensitive element which was then evaluated for development in dif~erent .-types o~ solvents. The photosensitive element ~Sample C) :-was prepared by mlxing the ingredients in ~able 3, at 50~C, in a 500-ml round-bottom flask equipped with a ,.
stirrer, a gas inle.t, a thermome~er, and a condenser.~.
The table below indicates the amount of each ingredient. ~.
Table 3 A Solder Mask Co~position ~Sample C) Containing , :~ 25 Non-Carboxvlat.ed Urethane Diacrvlate ~Sam~le 4) ~ : Formulation ~ams) ;~: Sample 4 urethane d~acrylate 122.5 : "Elvacite Z008" (trad~mark) 94~0 PMA . 131.0 ~,30 . Phenothiazine . 0.,00~4 "Irgacure 651" (trademark) 6.2 Leuco Crystal Violet ~.dye) 0.2 Develo~ment in 1,l,l"trichlo~oethane excellent 35 . in 1% aqueous K2C03 no development Abbreviatlons Used Above:
~Elvacite 2008"-.polymethyl methacrylate (M.W. ~ 79,000) PMA ~ propylene glycol monomethyl ether acetate "Irgacure 651"~ 2,2-dlmethoxy-2-phenylacetophenone .
.
'.: '': ' . . - 23 - 133209~ RMD ~929 The noncarboxylated uiethane diacrylate (Sample 4) had a very limited compatibility withT~he styrene/maleic anhydride resin ~"Scripset 550") Homo-geneous mixtures of the noncarboxylated urethane diacry-late and the styrene/maleic anhydride resin could be obtained only for a relatlvely short period of time (less :~
than one m~nth) but only when the ratio of the urethane diacrylate to the resin was less.than one. When the .
ratio is increased, phase separation occurred (Sample B).
The.carboxylated ureth~ne di or tri (meth)-acrylate, however, can have varying concentrations of carboxylation, allowing them to ~e miscible and compat- ,, tible in all proportions with the Ptyrene/maleic t, anhydride resin and other binder re~ins. The results are excellent shelf life, uniformity, and high perfor-mance in properties of the products.
ExamPle 8 Carboxylated urethane triacrylate samples were prpared using the apparatus and general procedure as described in Example 1. The specific ingredients for each triacrylate sample is given in the table below.
Table 5 _ SamPle 10 : Sam~le 11 (eq.) (wt. in gms) (eg.) (wt. ln gms) 1,6 ~exanediol 2.0118.0 "Tone 0301"* -~ 4.0 400.0 GlycerolDMPA 2.061.4 -~
DMPA 4.0268.0 4.0 268.0 : 2~EA 8.1939.6 --- --- .
Tone M-100"** --- --- 8.2 2820.8 !~
TMDI 16.01680.0 -~
IPDI ~ 16.0 1777.6 DTN --- --- --- 52.66 T-12 . ---30.67 --- ---M-Pyrol ---76~.8 --- 1316.6 Phenothiazlne --- 0.23 --- 0.395 Abbre.viations used in the above ~able:
Tone 0301 *o po}ycaprolactone triol with molecular weight of 300.
Tone M-100 = a reactive caprolactone acrylate * Trademark . ..
** Trademark .................... . .
'' ' : .~: .
. . . . .. ....
13 3 ~0 ~ 3 IPDI z $sophorone diisocyanate - 1-Isocyanato-3-isocyanato-methyl-3,5,5-trimethyl-cyclohexane The product of Samples 10 and 11 were then used to prepare the solder masks of Samples I and J, respectively.
The solder masks were prepared using the appa-ratus and general procedure as described in Example 2. :, Table 6 .
Solder Ma~k compo~itiPns Based On Carboxylated Urethane Triacrvlates Formu~ation SamPle I Sam~le J
:: " Modaflow~TM 1.10 1.10 N-methylpyrrolidone 41.8 41.8 15 " Scripset 650~T 30.68 30.68 ~
Phenothiazine . . O . 0024 0.0024 (Sample 10) 29.0 ---(Sample 11~ 29.0 Green Pigment 9G5 3.1 3.1 ITX 2.25 2.25 :,~
EPD 3.10 3.10 SR351 . 16.2 16.2 Develo~ment ~ro~ert,ies:
in 1% by weight aque~us K~C03 ~xcellent Excellent 25 MeCl2 resistance 6 min. (good) 8 min. (good) (Tested by ~mmerslng in the solvent for stated period of time and evaluating the results as good if no effect is seen, poor if a solvent effect is seen.) Crosshatch adhesion - ASTM-D335g-78 Method B
Scale 5 = no adhesion 105s Scale O = complete adhesion loss Adhesion before ~olten solder 5 4 -after molten solder 5 3 The boards used in the above tests were pre-35 pared usin~ Samples I and ~ in accordance with the pro-cedure de-cribed in EKample 3.
~ .j'`: .
- 1 - RMD-?929 A PHOTOIMAGABLE SOLDER Mi~SK COATING
' ~ "
5Backaround of the In~ention ~"r Field of the Invention '~
~; This invention relates to a photosensitive resin composition. More particula~ly, it relates to a photosensitive resin composition for forming a protec-, ,~. ~ , tive coating film having excellent characteristics which can be used either alone, to provide a photosensitive, t~acky coat; or it can be combined with a variety of ` other types of lngredlents such as a crosslinker to increase crossllnking density, a resin to remove tacki-ness, or even another photosensitive ingredient to increase sensitivity to light. The uses of the instant photosensitive coating material ehus includes photore-sist applications such as plating resist, etch resist and solder mask.
, .
Soldexing masks are used to produce printed ;~ wiring boards. ~he solder masks function is basically to prevent solder-ing bridges, to keep electric insula-tion between conductors thus prev~nting conduction be-tween solder areas and to prevent-the corrosion o~ a naked cop~er conductor. It is al$o desirable to have pho;toimagable solder masks which are able to retain an image which can be used as a blueprint on which the sol- ;
der is placed. Due to the desirability of increasing ~ , ` ~ t ~
wiring density, it is desirable to use a solder mask having preci~e resolution and extremely good electrical insulation properties. The instant photosensitive composition can provide these advantage~.
Known solder masks are described in U.S. Patent 4,499,163 which de~cribes a photosensitive resin composition containing urethane diacrylate or dimethacrylate, a linear polymeric compound having a glass transition temperature between about 40 and 150 C., and a sensitizer which generates free radicals in actinic light. The linear polymeric compound described includes the vinyl series linear polymers or copolymers such as, for example, polyers made from vinyl monomers including methyl methacrylate, butyl methacrylate, methyl styrene, vinyl toluene, and the like. The sensitizer for generating free radicals includes, for example, substituted and unsubstituted polynuclear quinones.
Another photocurable urethane acrylate resin composition ;
which also is described as being usable for permanent resists, can be found described in U.S. Patent 4,587,201. The composition therein described uses a urethane-acrylate resin ;~
which is composed of polybutadiene polymer. This resin is combined with a photo-polymerization initiator to form the ~-permanent resist material. `~
Most photoimagable solder masks, however, lack the ability of being developed in an aqueous solution. This necessitates the use of organic solvent developing solutions.
The use of such organic solvents has become undesirable due to the environmental regulations for solvent emissions control.
Another disadvantage found with solder masks that use ~ ;~
organic solvent developing solutions, is the continued ;~
sensitivity of the final product to organic solvents such as methylene chloride. In certain product applications, moreover, such susceptibility is undesirable.
X ~'"' 1332~
It ~s there~ore desirable to develop photo-imagable solder masks coatin~ compositlons whlch can be developed ln aqueous solutions, and which are resistant to organic solvents such as methylene chlorlde. It i8 an ob~ect oftthe instant lnventlon to provide such a coating composition. It ls al50 an ob~ect of the lnstant lnventlon to provide a solder mask coatin~ com-position which can be stripped with commercial alkaline :
strippers. Accordingly, the photosensltive resin como-slt~ons de~erlbed herein have excellent resolutlon, flexlbllity, adherance to metals, solvent resistance, hlgh temperature reslstance and electrlcal insulation properties.
Specific embod~ments of the lnstant composi- ~"
~5 tion provides a hl~hly viscous photosensitive material which ~s useful as an addltlve for composltions that require both thlckening and the additlon of a photosen-sltive coatlng material. In thls way, the lnstant pbo-tosensltive materials fulfill a dual role, both as a thickener and as a photosensltlve, photocurable addl-tlve. Such embodiments of the lnstant composltlons are thus useful photo~enslt~ve, photocurable thickenlng agents for material~ such as paints, lnks, etc.
Summarv of the Inventlon A photocurable coating composition lncludes a UV sensltive compound selected from: carboxylated urethane dlacryl~te, carboxylated urethane triacrylate, carboxylated urethane dlmethacrylate and carboxylated urethane trlmethacrylate. Thls group ls hereinafter referred to as carboxylated urethane di (and/or) i~ 1~ 1 , i .
tri(meth) acrylate. It is also understood that (meth)-acrylate is lntended hereln to mean acrylate and/or methacrylate.
These carboxylated urethane di and/or trl~meth)acrylates are prepared from acidified mo~eties which provlde the carboxyl group. These compositions are prepared by condensin~ a d~isocyanate, a carboxylic acld polyol, and a hydroxy alkyl (meth)acrylate.
.. .. . .
.. . . ~ , .
_ 4 _ 1332093 The carboxy]ic acid polyol should be present in an amount needed to provide at least about .3 milliequivalents of acid per gram of the combined arnount of the total amount of reactants; abbreviated herein as mel/g of TR (total reactants usually are the diisocyanate, carboxylic acid polyol, and hydroxyalkyl (meth)acrylate). In order to obtain a suitable level of photosensitivity in thisproduct, the hydroxyaLtcyl (meth)acrylate should be used in a minimum amount of about .5 milliequivalents per gram of the combined amount of the diisocyanate, carboxylate acid di- or triol and hydroxya1kyl (meth)acrylate.
The present invention, then, in one aspect, resides in a photoimagable coating composition comprising: a W sensitive polymer selected from the group consisting of: a carboxylated urethane dimethacrylate, a carboxylated urethane diacrylate, a carboxylated urethane triacrylate, and a carboxylated urethane trimethacrylate; said W sensitive polymer being made by condensing a reaction mixture comprising component (a) a diisocyanate having from 6 to 18 carbon atoms, component (b) a carboxylic acid polyol having the forrnula [OHl,~-R6-COOH; wherein x is an integer from 2 to 5, and wherein R~ is a linear or branched, saturated, unsaturated or aromatic, hydrocarbon moiety having from 2 to 29 carbon atoms, and component (c) a hydroxyaLtcyl (meth)acrylate wherein its a~yl has from 2 to 28 carbon atoms; provided that component (a) is present in an amount of from about 30 to about 80% by weight of the total amount of the reaction mixture; component (b) is present in an amount of from about 5 to about 45% by weight of the total amount of the reaction mixture with a minimum of about .3 millie~quivalents of acid per gram of the total amount of the reaction mixture, and component (c) is present in an amount of from about 5 to about 50% by weight of the total amount of the reaction mixture with a minimum amount of .5 milliequiYalents of acrylate p~r gram of the total amount of the reaction mixture.
l~e present invention, in another aspect, resides in a method for the preparation of a UV sensitive polymer comprising conducting a condensation reaction with a reaction mixture comprising: component (a) a diisocyanate havingfrom 6 to 18 carbon atoms, and component (b) a carboxylic acid polyol having ,''''~
.'~
- 4a - 1332033 the formula [OH~ COOH; wherein x is an integer from 2 to 5, and wherein R6 is a linear or branched, saturated, unsaturated or aromatic, hydrocarbon moiety having from 2 to 29 carbon atoms, and component (c) a hydroxyalkyl (meth)acrylate wherein its alkyl has from 2 to 28 carbon atoms; provided that S component (a) is present in an amount of from about 30 to about 80% by weight of the total amount of the reaction mixture; component (b) is present in an a nount of from about 5 to about 45% by weight of the total amount of the reaction mixture with a minimum of about .3 milliequivalents of acid per gram of the total amount of the reaction n~Lxture, and component (c) is present in anamount of from about 5 to about 50% by weight of the total amount of the reaction mixture with a minimum amount of .5 milliequivalents of acrylate per gram of the total amount of the reaction mixture.
The instant invention includes a variety of embodiments, achieved by combining the above coating composition with other specifically selected ingredients. Such ingredients, selected in order to provide or enhance a specific quality or characteristic, includes: a binder, a crosslin~ng agent, dyes, pigments, thermopolymerization inhibitors, and additives designed to improve coating properties.
Detailed Desc~tion The instant photocurable coating composition contains the carboxyl moiety, which alters the organophilic nature of the urethane (meth)acrylate polymer. As a result, the instant coating compositions become more organophobic, and thus are resistant to organic solvents such as methylene chloride. Further, these carboxylated photosensitive polymers can be mixed in large amounts with other hydrophilic binders and crosslinkers. In addition to this, ~e introduction of the carboxyl moie~ makes the instant coating compositions soluble or swellable in aqueous alkali solutions (pH in excess of 7.5) until exposure to W light. Advantageously, when the instant compositions are used to provide a photocurable coating, or solder mask, the development step can be done in aqueous alkali solutions. It can be noted that although the inco~poration of the carboxyl moeity changes the nature of the urethane (meth)acrylate, making ,, ~
4b 1332093 it soluble in aqu~ous .~,,~ ,,.
`'"
~ , : ., .
~, '~', ; ~ . ;', `
,, ; .
, . :
~.
, ~ 13 3 2 0 9 3 alkali, the sensitivity of the compound to UV light is retained. The carboxylation, moreover, improves adherance to metals. Thus, an improved solder mask is provided by ~he combination of a binder, a crosslinker, and a carboxylated urethane di (and/or) tri(meth~-acrylate. A preferred combination would use a copolymer of styrene/maleic anhydride as the binder (also provid-ing carboxyl groups). Preferred crosslinkers are the (meth~acrylate, and polyfunctional (meth)acrylate ~ono-mers.
Preferred carboxylated urethane di (and/or)tri(meth)aerylates of the instant inventlon can be represented by the following formula:
FormLla 1 Rl H ~ H ~ H H Rl CH=C-lCOR20C~NR3NC(OtR40~NR3NCO]~R50jNR3NC)nOR20CC=CH
O O O O O O O O
wherein n is an integer from 1 to 4; k can be either 0 or 1; and wherein Rl, derived from the acrylate reaction component (c) can be either a hydrogen or a methyl group; R2, also derived from the alkyl (meth)acrylate reaction component (c), can be a linear or branched saturated hydrocarbon moiety having from 2 to 28 carbon atoms; R3 is derived from the diisocyanate portion of the reaction mixture. R3 can be branched, linear or cyclic, saturated, unsaturated or aromatic hydrocarbon moiety. R3 can acceptably have from 4 to 20 carbon atoms, and preferably, has from 6 to 18 carbon atoms. For other preferred embodiments R3 is derived from the diisocyanate reactant selected from trimethyl-hexamethylene, hexamethylene, isophorone, tolylene,~
4,4,methylenebis(cyclohexyl), methylenediphenyl, and tetra methylxylene diisocyanates. R4 is a linear, cyclic or branched, aromatic, saturated or unsaturated hydrocarbon acceptably having from 2 to 28 carbon atoms. R4 can optionally also contain a hydroxyl moiety (remaining from the polyol used in the preparation of the composi-. f~ :
~. ! ~j ~
- 6 - RMD-7g29 1 133~0~
tion). R5 will be derived from a reaction mixture including (a) the carboxylîc acid polyol shown in and described for Formula 2; or ~b) the carboxylic acid ;:
polyol of Formula 2 and from the hydroxyl dicarboxylic acid shown in and described for Formula 3. Thus, R5 will always have at least one COOH moiety and will have a minimum of 3 carbon atoms. When R5 is derived from ta) (from Formula 2 compounds only) it will have only one -COOH group with a branched or linear; saturated, unsa-lo turated, or aromatic, acceptably, having a total of from 3 to 30 carbon atoms including the carboxyl carbon atom.
When R5 is derived from -(b) the overall composition will have R5 moleties derived from the carboxylic acid polyol -of Formula 2 and also F~5 moieties derived from the hydroxyl dicarboxylic acids of Formula 3. The R5 moie~
ties derived from the Formula 3 hydroxyl dicarboxylic ~i acid compounds will, ob~iously, have two COOH groups and ~ `
can also have from 3 to 30 carbon atoms, including the :
two carboxyl carbons. The descriptions given herein for ~-the Formula 2 and Formula 3 compounds will provide more information regarding the concentrations and preferred ~:~
structures of these R5 mo~eties.
It should be realized that the exact location '~
of each R5 moiety within the polymer molecule will depend upon the number of reactive hydroxyl groups of the Formula 2 or Formula 3 compound, and upon the somewhat random condensation reaction. For example, when R5 is derived from b) and when y of Formula 3 is one, R5 will be a terminal group having two COOH moieties; simultane-ously other R5 moieties from the same reaction mixture,~derived from the Formula 2 carboxylic acid polyol) will be randomly located within the backbone of the polymeric ;~
molecular structure as indicated above in Formula 1. .
In Form~la 1, the R2 preferably has from 2 to 16 carbon atoms, or, more preferably, is a moiety selected from the group consisting of: ethyl, propyl, - `
butyl, and: 1l ~ ;
(CH2 ~ C ~O(CH2)s C~m where m - 1 or 2.
~ . . :,.:,' .
1332~9~ RMD-7929 R4 ls derived from the optional polyol which can be added to the reaction mixture. R4 will, there-fore, have from 2 to 28 carbon atoms and from 2 to 5 oxygen atoms. The oxygen ato~s can possibly be in an unreacted hydroxyl moiety. When R4 i8 present, acceptably, it has from 2 to 28 carbon atoms or, R4 has, preferably, from 2 to 16 carbon atoms; still optionally having a hydroxyl moiety. Other preferred embodiments allow R4 to be a saturated or unsaturated hydrocarbon moiety havlng from 2 to 10 carbon atoms and from 2 to 5 oxygen atoms possibly as an unreacted hydroxyl group.
In specific examples of such preferred embodiments, R4 is a moiety selected from: ethyl, propyl, butyl, pen-tyl, hexyl, heptyl, and octyl and having from 2 to 5 oxygen atoms from the previous hydroxyl ~oieties. R
can also be derived from glyceryl or 2-ethyl-2-(hydro-xymethyl)-1,3propylene.
The carboxylated urethane d~ (and/or) tri(meth)-acrylates of the instant invent~on can be obtained by condensing a diisocyanate with a carboxylic polyol (see Formula 2) and a hydroxyalkyl(meth)acrylate in a one step reaction. The carboxyl-containing polyol can be any -~
carboxylic acid containing 2 or more hydroxyl moieties.
Sultably, there are from 2 to 5 hydroxyl groups.
Preferably, the carboxyl-containing polyol is either ~-a carboxylic acid diol or triol.
Suitably, therefore, the carboxylic acid polyol can have the formula shown in FoLmula 2 as follows:
FormNla 2 ~ HO ] X-R6-COOH
wherein x is an integer from 2 to 5 and R6 is a branched, cyclie or linear, saturated, unsaturated, or aromatic hydrocarbon moiety having from 2 to 29 carbon atoms. Preferably, R6 has from 2 to 24 carbon atoms while x is 2 or 3 Isuch as in a diol or triol). Most preferably, x is 2 and ~6 is a branched or linear; ~
~ saturated, unsaturated, or aromatic, hydrocarbon struc- ~-L~ ture with from 2 to 20 carbon atoms. A preferred embod- ~
~L , ~
iment uses an alpha- alpha dimethylol alkanoic acid as the ~
--8- 1 3 3 2 ~ ~ 3 !
carboxylated diol, most preferably, having an alkyl group having from 1 to 8 carbon atoms. Other preferred diol carboxylic acids are selected from: alpha-alpha-dimethylol acetic acid; alpha-alpha-dimethylol propionic acid, alpha-alpha-dimethylol butyric acid, alpha-alpha diethylol acetic acid; alpha-alpha diethylol propionic acid; alpha-alpha dipropylol propionic acid; alpha-alpha dipropylol butyric acid, and 2,3-dihydroxyl propanoic acid.
Optionally, a polyol can be additionally included in the reaction mixture. This will increase the molecular weight of the instant product. The presence of the polyol results in materials as depicted under Formula 1 wherein K = 1.
One embodiment of the instant invention can preferably be taken advantage of when a higher concentration of hydroxyl groups are provided, (such as by the addition of a polyol or by the use of a carboxylic acid as shown in Formula 2 where x is 3, 4, or 5). In this embodiment, a hydroxyl dicarboxylic acid is added to the reaction mixture. Formula 3 below shows a formula for some suitable hydroxyl carboxylic acids: ;
Formula 3 [HO]y~R7~(COOH)2 :-~
where y could be from 1 to 5, (preferably being from 1 to 3) and R7 is a linear, cyclic, or branched; saturated, unsaturated, or aromatic hydrocarbon moiety acceptably having from 1 to 28 carbon atoms; preferably, having from 1 to 18 and most preferably, from 1 to 12 carbon atoms. If y is from 2 to 5, R7 preferably ranges from 2 to 18 carbon atoms. Preferably, these diacids should be used when the hydroxyl concentration of the total reaction mixture is at least about .3 -~
milliequivalents of OH per gram of the combined amount of the reactants, (the diisocyanate, the carboxylic acid polyol, the hydroxyl alkyl(meth)acrylate, the hydroxyl dicarboxylic acid and the polyol if present). These diacids can suitably be used in an amount of from about .3 to about .7 milli-equivalents of acid per gram of the combined amount of the reactants. Some sultable hydroxy dicarboxylic acids can be selected from the group consistlng of; malic aoid, tartaric acld, dihydroxy tartaric acid, hydroxy adipie a~it, dihydroxy adlpic acid, and trihydroxy adipic acid.
~ hese dicarboxylic acids can b~ used to pro-vide thermally curable pendent or terminal ends. Advan-tageously, these ends can also provide reactive sites for future reaction with other materials. Melamine and epoxy for example are two compounds or moieties that can be reacted with the ter~inal carboxyl groups. By such reactions the characteristics of the material can be further ~odified or enhanced. The specific characteris-tics or qualitles des~red will depend on the intendeduse of the material.
To prepare the instant carboxylated urethane di (and/or) tri(meth)acrylate coating composition, the -reaction is carried out in a dry solvent solution which itself is non-reactive to the diisocyanate. Suitable examples of such solvents are ester6 like ethyl acetate and propylene glycol monomethyl ether acetate; ketones like methyl ethyl-ketone, ~ethyl isobutyl ketone, and N-methylpyrrol~done; aromatic hydrocarbons like toluene, xylene; and mixtures o~ the preceding.
The reaction preparing the instant coatlng compos~tion acceptably is conducted with the sol$ds content of the solution in the range of from about 20 to about 100%, preferably in the range of from about 35 to 95% and, most preferably, from about 65 to about 85%
by weight. The reaction temperature is generally from about 50 to about 95C., and preferably from about 6 to 85C. Preferably, homopolymerlzation is inhibited by the add$tion o~ a free radical polymeri~ation inhibitor such as hydroquinone, m-dinitrobenzene, Pheno-thiazine, and the like. Most preferably, they are used in an amount of from about 0.005X to about 1% by weight based on the weight of the solids.
' 1332~3 ~ - 10 - RMD-7929 . .
It is also preferred to use a condensation catalyst such as tin or amine catalysts. Such catalysts can be selected from the group consist~ng of: di-butyl tin dilaurate, dimethyl tin dineodecanoate, dibutyltin bisoctylthioglycolate, triethylamine, and triethylene diamine. For best results, the react~on is carried out under a dry air blanket.
The dilsQcyanate can be a hydrocarbon that is branched, l~near, or cyclic, saturated, unsaturated or aromatic. Acceptably, ~t has ~ro~ 4 to 20 carbon atoms, preferably, it has from 6 to 18 carbon atoms.
D~lsocyanates can be selected from the group consisting of: xylylene diisocyanate; 1-isocyanato-3-isocyanato-methyl-3,5,5-trimethylryclohexane; 3,3'-dimethyldiphenyl-~5 methane-4,4'-diisocyanate; 2,4,tolylenedlisocyanate;
2,6-tolylenediisocyanate; 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate:
methylene-bist4-cyclohexylisocyanate); hexamethylene-diisocyanate; ~eta-tetramethylxylenediisocyanate; para-tetramethylxylenedil ocyanate; ~ethylene-bis-phenyl-diisocyanate; 1,5-naphthylene diisocyanate; metaphenyl-lene diisocyanate and mixtures of the above. The most preferred diisocyanates are: 2,6-tolylenediisocyanate;
2,4,tolylene-diisocyanate, 1-isocyanato-3-isocyanato-methyl-3,5,5 trimethylcyclohexane; 2,2,4-trimethylhexa-methylene-diisocyanate, and 2,4,4,trimethylhexamethylene d~isocyanate.
When a polyol is lncluded, the ~olecular weight, cure speed, and crosslinking density will be increased. The polyol can have from 2 - 28 carbon atoms. Acceptably, the hydrocarbon portion can be branched or linear, saturated, unsaturated, or aroma~ -tic, and has from 2 - 5 hydrcxyl moieties. Preferably, the polyol is a diol or triol having from 2 to 16 carbon atoms. Preferred diols can be selected from: ethyle-ne glycol, propylene glycol, butanediol, Pentanediol, hexanediol, octanediol, neopentylglycol, 2-methylpro- ~i pane-l, 3-diol, cyclohexanedimethanol, and diethylene ;~ ' :
'' : , .
1332~
RMD-~929 glycol. Other preferred polyols include glycerol, tri-methylolpropane, or hexanetrlol which can also be used.
The hydroxyalkyl (meth)acrylate (Component C) can have an alkyl ~roup with from about 2 to 28 carbon atoms. The alkyl molety can also be llnear, cyclic, or branched, saturated or unsaturated. Prefer-ably, the alkyl ~roup of the hydroxylalkyl(meth)acrylate has from 2 to 12 carbon atoms. Some preferred hydroxy-alkyl (meth)acrylates can be selected from: hydroxyethyl-(meth)acrylate, hydroxypropyl~ (meth)acrylate, hydroxy-butyl (meth)acrylate, and compounds having the general formula:
O O o ,~
~: 11 p U
CH2'CH-C-O~C(CH2)50~mClCH2)50 where m is one or two.
When the instant coating composition is pre-pared, the concentratlons of the reactants should be such that the total concentratlon of the hydroxyl groups ls at lea~t approximately equal to the amount of dlisocyanate present. Broadly, this means that the concentratlon of the polyols, plus the dlols of the ~-dialkylol carboxylic acid, plus the hydroxyalkyl (meth)-acrylate is sufficient to brlng the ratio of the hydroxyl to the diisocyanate ,to at least about .95:1, and, pre-ferably, to at least 1:1. Most preferably, the hydroxyl moiety has the excess of equivalents. Preferably, the hydroxyl should have an excess eguivalents relative to -~
the dlisocyanate ln the range of from about 1.05:1 to about .95:1; most preferably, lt is in the range of from 1.02:1 to about 1:1. -`~
~I j The carboxylic acld polyol ls an important ; $ngredient of the instant coatlng composition, and is ;~
preferably present in an amount sufficient to allow the ;~
~ uncured copolymer to be soluble or swellable in aqueous -~
;~ 35 alkali solutions. Suitably, the carboxylic acid polyol is present ln a mlnimum amount of about .3 milliequiva-lents of acid/gram of the total amount of the reactants; ~ ~
preferably, in an a~ount equal to or greater than .5 ~;
milliequivalents of acid per gram of the total amount of reactants. -;
~ ~ 332093 Polar solubility is even more enhanced when the carboxylic acid polyol is used in the reaction mixture in an amount greater than .8 acid milliequivalents per gram of the total amount of the reactants (meq/g of TR).
A preferred range of acid meq/g of TR is from about .8 to 1.6 acid meq/g of TR. If a highly viscous product, extremely suitable for combination with other materials is desired, it is most preferred that the reacti~n mixture contains a minimum amount of about 1 acid meq/g of TR; a most preferxed range is from about 1 to about 1.6 acid meq/g of TR. The use of the diacid of Formula 3 can also be used to add to the amount of acid milliequivalents.
Another advantage provided by the carboxylation of the urethane di and tri(meth)acrylates is that the W sensitive compound can be combined with hydrophilic resins.
Furthermore, by varying the concentration of the carboxylation in the urethane di and tri(meth)acrylates, the hydrophilic nature of this W sensitive compound can, to an extent, be controlled. This allows the hydrophilic character to be set for a specific resin. Thus, when one desires to use a more hydrophobic or less hydrophilic resin, a low concentration of carboxylation can be used in the urethane di and tri(meth)acrylate, to increase compatibility with the selected resin. Conversely, if one desires to use a hydrophilic resin, the carboxyl concentration would be increased so that the resin and the urethane di and tri(meth) acrylate could be i~
mixed in larger concentrations. Acceptably, the carboxylic acid polyol can be used in the reaction mixture in concentrations having the carboxylated polyol in an amount of from about 5 to about 45% by weight of the total amount of reactants (abbreviated as: by weight of TR), preferably, from about 5 to about 25~ by weight of TR, most preferably, from about 12 to about 25~ by weight of TR.
Y ::
it~ :
` - 13 - 1332~93 RMD-7929 When a specific polyol is also included,l it can be used in the reaction mixture in an a~ount of from about 2 to about 18% by weight of TR; and pre-ferably, having from about 2 to about 15% by weight of S TR. ~ ,.
i For the diisocyanate, an acceptable concen- ~:~
tration range is from about 30 to about 80% by weight of the TR. Preferably, it is in the range of from about , 50 to 75% by weight of TR. ~-The hydroxyalkyl(meth)acrylate must be pre~
sent in the reaction mixture in a minimum amount of i-about 0.50 meq of acrylate/g of TR to assure suitable VV .
sensltivity. A suitable range is from about .5 to about ~; 1.6 meq of acrylate/g of TR. An acceptable weight per-cent range is in an amount of from about 5 to about 50 by weight of TR and, preferably, it is used in an amount ~
of from about 10 to about 30% by weight of TR. ~;,.
The instant carboxylated urethane di ~and/or) i}~, tri~meth)acrylate copolymer coating composition can ~
acceptably have a weight average molecular weight of ,,3'~.
from about 500 to about 6,500, preferably, from about ;~
800 to about 3,000, and, most preferably, from about 1,000 to about 2,500 (determined by the Gel Permeation Chromatogsaph and based on a standard polystyrene cali~
bration curve).
In one preferred embodiment, the instant coat- ~
ing composition is combined with a binder. The resin -, which ls used for this preferably, should have a glass transition temperature (Tg) of about 155C. or greater, and most preferably is hydrophilic. The hlgh (Tg) will h,~
~ improve temperature resistance. Several commercially `i available resins can be used. Compatible mixtures can be achleved with the instant carboxylated urethane di (and~or) tri(meth)acrylates especially by advantageously varying the carboxyl concentration. Acceptable resins that can be used for this purpose are styrene/maleic anhydride copolymersi, particularly those which have been partlally esiterified wlth low molecular weight :"
: . .
~ ....
. ~, . - . ~
~ 14 - 13~2093 ~MD-7929 alcohols. Copolymers of styrene/maleic anhydride are eommercially avallable which have been esterified wlth m~xtures of alcohols from methyl to butyl. Such copoly-mers are commerclally available ln a wlde range Or mole-cular weights,. Acceptably, the molecular we~ght of this resin-binder should be in the range of from about 25,000 to about 300,000; and, most preSerably, from about 60,000 to about 250,000. Preferably, the copoly-mer used has a ratio of styr-ne to maleic anhydride in the range of ~rom about 1:1 to about 2:1. A preferred (Tg~ range for the binder is from about 155-C. to about 200-C.
Acceptably, the binder can be used in an amount of from about 85 to about 25X by weight of the total compositi-on, and, preferably, from about 1~ to about 60% by weight of the total composition.
Preferably, the carboxylated urethane di land~or) tri(meth)acrylate coating composition is mixed with the -~
- binder 80 that the glass transition temperature (Tg) of the end product is from about ?0 to about l90-C.
Preferably, the blnder acid number is from about 120 to about 280 mg of KOH/g of the blnder. Other polymers having the above described molecular weight, Tg, and acid number can also be used as a b$nder with the instant carboxylated urethane di (and/or) tri(meth)-acrylate coating composition. Suitable polymers for use ~
as binders include: methylmethacrylate-comethacrylic ~ -acld and methylmethacrylate-methylacrylate methacrylic acid.
~;~ 30 When the lnstant carboxylated urethane di ~-(and/or) tri(meth)acrylate ls used with other materials such as the above described binders, or other additives which can permissively be added such as crosslinkers, ;;~
dyes, solvents, pigments, photoinitiators, thermal inhibltors, the concentration of the UV sensitive car-boxylated coating ingredient should be in the range of from about 10 to about 85X by weight of th~ total com-bined composition. Preferably, it is in the range of ~r ~
~; ., from about 15 to about 75% and, most preferably, it is in the range of from about 17 to about 60% by weight of the total combined composition.
Preferred crosslinkers are the (meth)acrylate ~onomers. Crosslln~ers are used when lt ls deslrable to obtain a compositlon havin~ a greater crosslinking density, wh~ch in turn improves resistance to solvents such as methylene chloride. More preferred, are poly-functional ~meth)acrylate monomers. Such polyfunctional monomers can be selected ~rom: trimethylolpropanetri- ~
(meth)acrylate,trimethylolpropaneethoxylated tri(meth)- ;
acrylate, dipentaerythrltolhydroxypentaacrylate, and ditrimethylolpropanetetraacrylate.
Other crosslinkers which can be used can be selected fro~ th~ ~roup consisting of: divinyl ethers, acrylated epoxies, epoxy resins, and aminoplast reslns.
The acrylated epoxies are preferred since they lmprove ;~
overall heat resistance, solvent resistance, and overall adhes~on.
When the instant carboxylated coating compo-sition is used as a solder mask, the composition is `~
coated on an appropriate substrate, and dried to a tack free conditio~. The coated substrate is then photo~
i~aged with from about ?5-to 105 mJ/sg. cm. of UV
radiation, and then can be developed with an aqueoùs ~
a~kali solutlon. Preferably, the aqueous alkali so~u- `-tion is potassium or sodium carbonate. Generally, the` :
photoimaged coated substrate is inspected at this point.
When the instant coating composition is used, it is advantageous in that, $f desired, a coating can ~-be easily stripped with an aqueous alkaline stripper, and redone. The amount of al~ali needed in the strip-ping or developing solution ls very low. A solution which is lX by weight of the a base can be used. When the desired quality of an image i~ obtained, the instant coating can be given a post UV cure of 3 - 5 3/sq. cm.
This i5 followed by a heat cure, preferably, at 150C.
.. :
~,.
for a sufficient curing time. The instant compositions -ha~e excellent resolution, flexibility, and adherance to metals. -The instant inventlon can also be readily ~
understood from the examples that follow. It should be ~:
understood, however, that these examples are offered to illustrate the instant invention, and thus, they should not be used to limit it. All parts and percentages are '',"',;r by weight unless otherwise indicated.
Exam~le 1 The following example illustrates a prepara~
tion for the photoimagable coating composition.
~he following ingredients were added to a 5 ; liter round-bottomed flask, fitted with a mechanical P~.:
stirrer, a thermometer, a condenser, a gas inlet, and a ~.
heating mantle: 236.0 grams ~g), (about 4 equivalents), of 1,6-hexanediol; 268.0 g. tabout 4 equivalents) of di-methylolpropionic acid; 951.2 g. (about 8.2 equivalents) ; of 2-hydroxyethylacrylate; 0.23514 g. of phenothiazine is as a free radical inhibitor: ~83.8 g. of N-methyl-2- ;~
pyrrolidone as a solvent; and 31.35 g. of dibutyltin~
dilaurate ~T-12) as a catalyst. Under a dry-air blanket with agitation, 1,680.0 g. (about 16 equivalents) of tri-methylhexamethylenediisocyanate was charged into the mixture in two equal portions which were 30 minutes apart. An exotherm took place for each addition. The reaction temperature was kept under 85C. by cooling -~;
with an ice-water bath, and after the second addition of trimethylhexamethylenediisocyanate the reaction tem-perature was maintained at a constant 85C. for 10-12 ~
hours until the isocyanate infra-red absorption peak ;:~-had disappeared, which indicated that the reaction had ~-i ~ gone to completion.
: Exam~le 2 The photosensitive coating compos~tion which was prepared in Example 1 was used to prepare a photo-i~aga~le solder mas~. The solder mask was prepared by charging the following ingredients to a 500 ml. round-, . .
.. , ~ 1 3 3 2 o 9 3 RMD-7929 bottom flask, equipped with a stirrer, a gas inlet!, a thermometer, and a condenser: 6.5 g. of a low mole-¢ular weight copolymeric defoaming ~gent; 91.25 g. of N-methyl-2-pyrrolidone as a solvent; 82.0 g. of an esterified styrene/maleic anhydride copolymer was added as a binder. (The resin used here was"Scripset 550"by Monsanto). The mixture was agitated and heated to 95~C. ~or 30 minutes to obtain a hazy solution. After ' this, the temperature was lowered to 70C., and then the following ingredlents were added to the mixture:
0.004 g. of the free radical polymerization inhibitor, phenothiazine; ~.S g. of the UV sensitive coating com-position prepared ln Example 1, and 9.0 g. of a green pigment. While the'mixture was blanketed with a flow of dry air, a premix~d solution containing the follow-ing was added: 47.8 g. of trimethylolpropanetriacrylate (SR351) as a crosslinker, 6.5 g. of 1sopropylthioxan-thone (abbreviated as ITX) as a photoinitiator and 8.4 g. of ethyl p-dimethylaminobenzoate (abbreviated as EPD) as a sensitizer. ' The above insredients were allowed to mix under a dry alr b!anket for 30 minutes at ~0C., after which time they were discharged into an amber ~ar. The solder mask thus prepared was used as described in .-Example 3. '' Exam~le 3 The comp'os-ition prepared in ~xample 2 was applied as a coating to two 6" x 8" bare copper clad epoxy boards in a thickness of about two mils, using a 75 mesh monofilament polyester screen, and a rubber squeegee having ~0 durometer hardness. This wet coat-ing was dried to a 1.4 mil tack-free film in a forced-air oven at 100C. in a period of 12 minutes.
- After these dried films were cooled to room temperature, they wer~ exposed at 75 m~/sq. cm. through an IPC (Institute for Interconnecting Packaging elec-tronic circuit~) No. B-25 negative artwork with 400 watt mercury vapor Iamp. The exposed films were then * Trademark .. . . .. .
: ** Trade~ark '' ., ... .: , .
.
- 18 - 3 2 0 ~3 RMD-~929 developed manually in a 1% solutio~ of K2C03 for 45 seconds, and then rinsed with fresh water. .~-An excellent resolution of the IPC B-25 was produced.
After this development, the boards were cured , at 3 J/sq. cm., and thermal baked at 150'C. for one hour -.
as a post-cure process. -~
One of the boards was then soaked in methy-lene chloride (abbreviated MeCl2) for 15 minutes, and no degradation was found on the mask (solvent resistance test). ,.
The other board was given a cross-hatch adhe-sion test according to ASTM D3359-78 method B, and was found to have no adhesion loss. The board waR then ~.
painted with a resin flux, and floated with the face having the solder mask down on a molten solder pot at 260-275C. for 10 seconds. After the solder pot test, the board was immediately rinsed with l,1,1-trichloro-ethane while the board was s~ill warm. One hour later, the board was given the same cross-hatch adhesio~ t~6t and found to have no adhesion 105s.
Exam~le 4 ,~!`.
Using the apparatus and general procedure as described in Example 1, urethane diacrylate oligomers were prepared which varied in the amount of car-boxylatlon. Sample 4 contained no carboxylation and Sample 9 contained the highes~ amount of carboxylation.
All of the samples were prepared at 80X solids. The formulation used for each individual sample is shown in .~
Table 1 below. ~;
Table 1 The following abbreviations have been employed.
DMPA = dimethylolpropionic acid 2HEA = 2-hydroxyethyl acrylate TMDI = trimethylhexamethylene diisocyanate DTN = dimethyl tin dineodecanoate M-Pyrol - N-methylpyrrolidone .
eq. = equivalent . - 19 - - RMD-~929 Sam~le 4 Sam~le 5 ¦ eq. Welaht eq. Welaht (g~s) ~gmsl 1,6 Hexanediol 8 472 7.0413.0 DMPA - - 1.0 67.0 2HEA 8.1939.6 8.2951.2 ~MD~ 161680.0 16.01680.0 DTN - 15.46 -15.56 M-Pyrol - ~2.9 -~77.8 Phenothiazine - 0.309 -0.311 SamDle 6 Sample ~ ~`
¦ ea. Weiaht eg. Welcht :~
: ~gms) (gms) 1,6 Hexanediol 3.01~7.0 2.0118.0 `~
DMPA 5.0335.0 6.0402.0 2HEA 8.2951.2 8.2951.2 :~ TMD~ 16.01680.0 16.01680.0 DTN - 15.~2 -15.76 M-Pyrol - 785.8 -762.8 :~
Phenothiazine - 0.314 -0.315 Sam~ie 8 Sam~le 9 e~. Weiqht ~ Wei~ht (gms) (gms) 1,6 Hexanedlol 1.0 59.0 0 0 DMPA ~.0469.0 8.0536.0 2HEA 8.2951.2 8.2951.8 .:
TMDI 16.01680.0 16.01680.0 DTN . - 15.8 -31.67;
~ '~ M-Pyrol - 789.8 -791.8 :~
-~ 30 Phenothiazine - 0.316 -0.31~
i The viscosities of Samples 4 - 9 were measured ~: (in C~S) at ~5-F; using a"Brookfield RVT Viscometer, #6 spindle at 10 RPM. ;~
: Sample # 4 5 6 ~ 8 9 Viscosity 20400 2240~)41600 44800 68800 86gO0 : ~ ~ ` ' '''''.;'~ '"
' .-~ ' .
* Trademark `~`` - - 20 - 133~93 RMD-~929 ~xamPle 5 Samples 5-9 of the carboxylated urethane acry- -lates were used to prepare solder masks. These solder ~:
masks were then tested for comparison of properties.
This example, alon~ with examples 6 and 7 which follow, can be used to compare the properties of the carboxylated urethane acrylates to masks containing the noncarboxylated urethane acrylates. !~
The solder masks designated herein as Example ~-lo D - H were prepared using the apparatus and general pro- ~-cedure as described in Example 2.
The amount of each ingredient is given in the ti following table: ~-Table 2 A Common Solder Mask Formula for Sam~les D - H
" Modaflo~'(a low molecular weight copolymer)- 6.5 N-methyl pyrrolidone -91.25 Styrene~maleic anhydride ~'Scripset 55d)** 82.0 Phenothiazine 0.00~ ;:
.
Carboxylated Urethane Acrylate ~.5 Green Pi~ment ~9G5) 9.0 Isopropyl Thioxanthone 6.5 Ethyl p-dimethylamino benzoate 8.4 Trimethylolpropyl triacrylate (SR351)*** 4~.8 Summarv of Pro~erties of Solder_Masks ,. .
Contalnin~ Carboxvlation Solder Mask (Sam~le-No.) D E F G H
Carboxvlated Urethane 5 6 7 8 9 :
Using the solder masks of Samples D-H, bare, 30 copper clad epoxy boards were coated using the general 1.
method as described in Example 3. The boards were then tested and evaluated.
Photos~eed - was excellent at ~5 m~/cm2 for Samples D-H.
Develo~ment: For Samples D-H in a 1% aqueous K2C03 35 solution for samples was excellent.
In 1,1,1 trichloroethane development for Sample D-H was poor.
* Trademark ** Trademark *** Trademark :; '' " , : .
Adhesion Test Method: ASTM-D3359-78 Method B , , (Scale 5 = No adhesion loss) . ;
~Scale 0 = Complete adhesion loss) _.
Sample Number D E F G H i S Adhesion before molten solder 5 4-5 4-5 5 4-5 ..
.~.dhesion aft~`- molden solder was applied 5 5 5 5 5 ~/~
Exam~le 6 .
Sample~ of a solder mask composition, using the Sample 4 no~carboxyla~ed material, was prepared as follows described in Example 2. -The in~redient~ and amounts of the ingredients are given in the following table: ..
Table 3 ~, Solder Mask Solder Mask Formulation Sam~le A SamPle B ;
(Defoamer) 1.10 1.30 .
N-methylpyrrolidone 41.8 50.35 Scripset 550 30.68 36.50 Phenothiazine 0.0024 0.003 : Green Pigment (9G5) 3.1 3.1 Sample 4 29.0 ~5.0 `
SR351 16.2 ---Isopropyl Thioxanthone 2.25 3.0 EPD 3.1 4.0 To provide a comparison using the procedures ~:: as described in Example 3 each of these formulations ~ .
A&B) were tested and used to coat a bare copper clad epoxy board which was ~urther characterized. The :
~: ` 3~ results are given below~
: Solder Mask Solder Mask SamPle A Sam~le B
Limited Compatibility Total Phase Separation :
~: Sta~lity at 75F 1 month ~: 35 De~elo~ment 1% aq. K2C03 excellent ---1,1,1, trichloroethane poor ---~ 22 - ~3~093 RMD-792g Pro~ertv . ~.
Methylene Chloride Resistance was,,poor showing the ~,i solvent's effect after only a 2 min. exposure.
Adhesion before molt~n.solder* , 5 l,, after molten solder~ 5 ,, SR351 = Trimethylolpropane triacrylate ITX = Isopropyl thioxanthone EPD z ~thyl p-dlmethylamino benzoate ':
* crosshatch adhesion - ASTM-D3359-78 Method B .
. Scale 5 = no adhesion loss Scale 0 - complete adhesion loss ~xam~le 7 Also for the purposes of comparison, Sample 4ii "~ .
material was used to prepare a photosensitive element which was then evaluated for development in dif~erent .-types o~ solvents. The photosensitive element ~Sample C) :-was prepared by mlxing the ingredients in ~able 3, at 50~C, in a 500-ml round-bottom flask equipped with a ,.
stirrer, a gas inle.t, a thermome~er, and a condenser.~.
The table below indicates the amount of each ingredient. ~.
Table 3 A Solder Mask Co~position ~Sample C) Containing , :~ 25 Non-Carboxvlat.ed Urethane Diacrvlate ~Sam~le 4) ~ : Formulation ~ams) ;~: Sample 4 urethane d~acrylate 122.5 : "Elvacite Z008" (trad~mark) 94~0 PMA . 131.0 ~,30 . Phenothiazine . 0.,00~4 "Irgacure 651" (trademark) 6.2 Leuco Crystal Violet ~.dye) 0.2 Develo~ment in 1,l,l"trichlo~oethane excellent 35 . in 1% aqueous K2C03 no development Abbreviatlons Used Above:
~Elvacite 2008"-.polymethyl methacrylate (M.W. ~ 79,000) PMA ~ propylene glycol monomethyl ether acetate "Irgacure 651"~ 2,2-dlmethoxy-2-phenylacetophenone .
.
'.: '': ' . . - 23 - 133209~ RMD ~929 The noncarboxylated uiethane diacrylate (Sample 4) had a very limited compatibility withT~he styrene/maleic anhydride resin ~"Scripset 550") Homo-geneous mixtures of the noncarboxylated urethane diacry-late and the styrene/maleic anhydride resin could be obtained only for a relatlvely short period of time (less :~
than one m~nth) but only when the ratio of the urethane diacrylate to the resin was less.than one. When the .
ratio is increased, phase separation occurred (Sample B).
The.carboxylated ureth~ne di or tri (meth)-acrylate, however, can have varying concentrations of carboxylation, allowing them to ~e miscible and compat- ,, tible in all proportions with the Ptyrene/maleic t, anhydride resin and other binder re~ins. The results are excellent shelf life, uniformity, and high perfor-mance in properties of the products.
ExamPle 8 Carboxylated urethane triacrylate samples were prpared using the apparatus and general procedure as described in Example 1. The specific ingredients for each triacrylate sample is given in the table below.
Table 5 _ SamPle 10 : Sam~le 11 (eq.) (wt. in gms) (eg.) (wt. ln gms) 1,6 ~exanediol 2.0118.0 "Tone 0301"* -~ 4.0 400.0 GlycerolDMPA 2.061.4 -~
DMPA 4.0268.0 4.0 268.0 : 2~EA 8.1939.6 --- --- .
Tone M-100"** --- --- 8.2 2820.8 !~
TMDI 16.01680.0 -~
IPDI ~ 16.0 1777.6 DTN --- --- --- 52.66 T-12 . ---30.67 --- ---M-Pyrol ---76~.8 --- 1316.6 Phenothiazlne --- 0.23 --- 0.395 Abbre.viations used in the above ~able:
Tone 0301 *o po}ycaprolactone triol with molecular weight of 300.
Tone M-100 = a reactive caprolactone acrylate * Trademark . ..
** Trademark .................... . .
'' ' : .~: .
. . . . .. ....
13 3 ~0 ~ 3 IPDI z $sophorone diisocyanate - 1-Isocyanato-3-isocyanato-methyl-3,5,5-trimethyl-cyclohexane The product of Samples 10 and 11 were then used to prepare the solder masks of Samples I and J, respectively.
The solder masks were prepared using the appa-ratus and general procedure as described in Example 2. :, Table 6 .
Solder Ma~k compo~itiPns Based On Carboxylated Urethane Triacrvlates Formu~ation SamPle I Sam~le J
:: " Modaflow~TM 1.10 1.10 N-methylpyrrolidone 41.8 41.8 15 " Scripset 650~T 30.68 30.68 ~
Phenothiazine . . O . 0024 0.0024 (Sample 10) 29.0 ---(Sample 11~ 29.0 Green Pigment 9G5 3.1 3.1 ITX 2.25 2.25 :,~
EPD 3.10 3.10 SR351 . 16.2 16.2 Develo~ment ~ro~ert,ies:
in 1% by weight aque~us K~C03 ~xcellent Excellent 25 MeCl2 resistance 6 min. (good) 8 min. (good) (Tested by ~mmerslng in the solvent for stated period of time and evaluating the results as good if no effect is seen, poor if a solvent effect is seen.) Crosshatch adhesion - ASTM-D335g-78 Method B
Scale 5 = no adhesion 105s Scale O = complete adhesion loss Adhesion before ~olten solder 5 4 -after molten solder 5 3 The boards used in the above tests were pre-35 pared usin~ Samples I and ~ in accordance with the pro-cedure de-cribed in EKample 3.
~ .j'`: .
Claims (21)
1. A photoimagable coating composition comprising: a UV sensitive polymer selected from the group consisting of: a carboxylated urethane dimethacrylate, a car-boxylated urethane diacrylate, a carboxylated urethane triacrylate, and a carboxylated urethane trimethacry-late; said UV sensitive polymer being made by condensing a reaction mixture comprising component (a) a diiso-cyanate having from 6 to 18 carbon atoms, component (b) a carboxylic acid polyol having the formula [OH]X-R6-COOH; wherein x is an integer from 2 to 5, and wherein R6 is a linear or branched, saturated, unsaturated or aromatic, hydrocarbon moiety having from
2 to 29 carbon atoms, and component (c) a hydroxy-alkyl (meth)acrylate wherein its alkyl has from 2 to 28 carbon atoms; provided that component (a) is present in an amount of from about 30 to about 80% by weight of the total amount of the reaction mixture; component (b) is present in an amount of from about 5 to about 45% by weight of the total amount of the reaction mixture with a minimum of about .3 milliequivalents of acid per gram of the total amount of the reaction mixture, and component (c) is present in an amount of from about 5 to about 50% by weight of the total amount the reaction mixture with a minimum amount of .5 milliequivalents of acrylate per gram of the total amount of the reaction mixture.
2. A composition as described in Claim 1 also having a binder.
2. A composition as described in Claim 1 also having a binder.
3. A composition as described in Claim 1 wherein the reaction mixture also includes a polyol hav-ing from 2 to 28 carbon atoms, and from 2 to 5 hydroxyl moieties.
4. A composition as described in Claim 1 wherein the reaction mixture also includes a dicarboxylic acid having the formula:
[OH]y-R7-(COOH)2 wherein y is an integer from 1 to 5 and wherein R7 is a hydrocarbon moiety having from 1 to 28 carbon atoms.
[OH]y-R7-(COOH)2 wherein y is an integer from 1 to 5 and wherein R7 is a hydrocarbon moiety having from 1 to 28 carbon atoms.
5. A composition as described in Claim 1 wherein component (b) is selected from the group consisting of: alpha-alpha-dimethylol acetic acid, alpha-alpha-dimethylol propionic acid, alpha-alpha-dimethylol butyric acid, alpha-alpha-diethylol acetic acid, alpha-alpha-diethylol propionic acid and alpha-alpha-diethylol butyric acid.
6. A composition as described in Claim 2 wherein the binder is a styrene/maleic anhydride copoly-mer having a glass transition temperature of about 155°C. or greater.
7. A composition as described in Claim 1 wherein the reaction mixture has from about .8 to 1.6 milliequivalents of acid per gram of the total amount of the reaction mixture.
8. A composition as described in Claim 4 wherein the reaction mixture also contained a polyol having from 2 to 5 hydroxyl moieties, and from 2 to 28 carbon atoms.
9. A composition as described in Claim 1 wherein the diisocyanate is selected from the group con-sisting of: 1-isocyanato-3-isocyanato-methyl-3,5,5-trimethylcyelohexane;xylylenediisocyanate; 3,3'-dimethyl diphenylmethane-4,4'-diisocyanate; 2,4,tolylene-diisocyanate; 2,6-tolylene diisocyanate; 2,2,4-trimethyl-hexamethylene diisocyanate; 2,4,4-trimethylhexamethylene diisocyanate; methylenebis(4-cyclohexylisocyanate);
hexamethylene diisocyanate; 1,5-naphthylene diisocyanate meta phenylenediisocyanate; meta-tetramethylxylene diisocyanate; paratetramethylxylene diisocyanate; and methylenebisphenyldiisocyanate.
hexamethylene diisocyanate; 1,5-naphthylene diisocyanate meta phenylenediisocyanate; meta-tetramethylxylene diisocyanate; paratetramethylxylene diisocyanate; and methylenebisphenyldiisocyanate.
10. A composition as described in Claim 9 which also contains a crosslinker.
11. A composition as described in Claim 9 also having a binder.
12. A composition as described in Claim 9 wherein the reaction mixture also includes a polyol hav-ing from 2 to 28 carbon atoms, and from 2 to 5 hydroxyl moieties.
13. A composition as described in Claim 9 wherein component (b) is selected from the group consisting of: alpha-alpha-dimethylol acetic acid, alpha-alpha-dimethylol propionic acid, alpha-alpha-dimethylol butyric acid, alpha-alpha- diethylol acetic acid, alpha-alpha-diethylol propionic acid and alpha-alpha-diethylol butyric acid.
14. A method for the preparation of a UV sen-sitive polymer comprising conducting a condensation reaction with a reaction mixture comprising: component (a) a diisocyanate having from 6 to 18 carbon atoms, and component (b) a carboxylic acid polyol having the formula [OH]x-R6-COOH; wherein x is an integer from 2 to 5 and wherein R6 is a linear or branched, saturated, unsa-turated or aromatic, hydrocarbon moiety having from 2 to 29 carbon atoms, and component (c) a hydroxy alkyl (meth) acrylate wherein its alkyl has from 2 to 28 carbon atoms;
provided that component (a) is present in an amount of from about 30 to about 80% by weight of the total amount of the reaction mixture; component (b) is present in an amount of from about 5 to about 45% by weight of the total amount of the reaction mixture with a minimum of about .3 milli-equivalents of acid per gram of the total amount of the reaction mixture, and component (c) is present in an amount of from about 5 to about 50% by weight of the total amount of the reaction mixture with a minimum amount of .5 milliequivalents of acrylate per gram of the total amount of the reaction mixture.
provided that component (a) is present in an amount of from about 30 to about 80% by weight of the total amount of the reaction mixture; component (b) is present in an amount of from about 5 to about 45% by weight of the total amount of the reaction mixture with a minimum of about .3 milli-equivalents of acid per gram of the total amount of the reaction mixture, and component (c) is present in an amount of from about 5 to about 50% by weight of the total amount of the reaction mixture with a minimum amount of .5 milliequivalents of acrylate per gram of the total amount of the reaction mixture.
15. A method as described in Claim 14 wherein the diisocyanate is selected from the group consisting of: 1-isocyanato-3-isocyanato-methyl-3,5,5-trimethyl-cyclohexane; 2,4,tolylenediisocyanate; 2,6-tolylene diisocyanate; 2,4,4-trimethylhexamethylene diisocyanate;
2,2,4-trimethylhexamethylene diisocyanate;
methylene-bis(4-cyclohexylisocyanate); hexamethylene diisocyanate; meta-tetramethylxylene diisocyanate;
xylylene diisocyanate; 3,3'-dimethyldiphenyl-4,4'-diisocyanate; 1,5-naphthylene diisocyanate; metaphenylene diisocyanate,paratetramethylxylene diisocyanate; and methylenebisphenyl diisocyanate.
2,2,4-trimethylhexamethylene diisocyanate;
methylene-bis(4-cyclohexylisocyanate); hexamethylene diisocyanate; meta-tetramethylxylene diisocyanate;
xylylene diisocyanate; 3,3'-dimethyldiphenyl-4,4'-diisocyanate; 1,5-naphthylene diisocyanate; metaphenylene diisocyanate,paratetramethylxylene diisocyanate; and methylenebisphenyl diisocyanate.
16. A method as described in Claim 14 wherein the reaction mixture also contains a polyol having from 2 to 5 hydroxyl groups and from 2 to 28 carbon atoms.
17. A method as described in Claim 14 wherein the reaction mixture also includes a dicarboxylic acid having the formula:
[OH]y-R7-(COOH)2 wherein y is an integer from 1 to 5 and wherein R7 is a hydrocarbon moiety having from 1 to 28 carbon atoms.
[OH]y-R7-(COOH)2 wherein y is an integer from 1 to 5 and wherein R7 is a hydrocarbon moiety having from 1 to 28 carbon atoms.
18. A method as described in Claim 14 wherein the reaction mixture has from about.8 to 1.6 milliequi-valents of acid per gram of the total reaction mixture.
19. A method as described in Claim 14 wherein the temperature of the reaction mixture is in the range of from about 50 to 95°.
20. A method as described in Claim 14 wherein the reaction mixture also contains a free radical poly-merization inhibitor and a condensation catalyst.
21. A method as described in Claim 20 wherein the reaction mixture is at a temperature in the range of from about 50 to 95°C, and is under dry air during the reaction.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US93960486A | 1986-12-08 | 1986-12-08 | |
| US939,604 | 1986-12-08 | ||
| US4546487A | 1987-05-04 | 1987-05-04 | |
| US45,464 | 1987-05-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1332093C true CA1332093C (en) | 1994-09-20 |
Family
ID=26722797
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000550900A Expired - Fee Related CA1332093C (en) | 1986-12-08 | 1987-11-03 | Photoimagable solder mask coating |
Country Status (13)
| Country | Link |
|---|---|
| KR (1) | KR910001523B1 (en) |
| CN (1) | CN1031227C (en) |
| BR (1) | BR8706609A (en) |
| CA (1) | CA1332093C (en) |
| CH (1) | CH680622A5 (en) |
| DE (1) | DE3741385C2 (en) |
| FR (1) | FR2607820B1 (en) |
| GB (1) | GB2199335B (en) |
| HK (1) | HK60692A (en) |
| IT (1) | IT1233418B (en) |
| MX (1) | MX168832B (en) |
| NL (1) | NL190785C (en) |
| SG (1) | SG61192G (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR910021456A (en) * | 1990-02-20 | 1991-12-20 | 우메모토 요시마사 | Water-soluble photocurable polyurethane poly (meth) acrylates, adhesives containing them and methods of making laminated articles |
| CA2040097A1 (en) * | 1990-04-12 | 1991-10-13 | Wako Yokoyama | Urethane polymers for printing plate compositions |
| US5341799A (en) * | 1991-12-23 | 1994-08-30 | Hercules Incorporated | Urethane polymers for printing plate compositions |
| BR0014422A (en) * | 1999-09-30 | 2002-06-11 | Basf Ag | Aqueous dispersion of u.v. and heat, and, use of polyurethane dispersion |
| TW201220974A (en) * | 2010-05-21 | 2012-05-16 | Nano Terra Inc | Stencils for high-throughput micron-scale etching of substrates and processes of making and using the same |
| CN104193944A (en) * | 2014-08-21 | 2014-12-10 | 苏州瑞红电子化学品有限公司 | Controllable-acid-value photosensitive alkali-soluble polyurethane acrylate resin and photoresist composition thereof |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4153778A (en) * | 1978-03-30 | 1979-05-08 | Union Carbide Corporation | Acrylyl capped urethane oligomers |
| NL8401785A (en) * | 1984-06-04 | 1986-01-02 | Polyvinyl Chemie Holland | PROCESS FOR PREPARING AN AQUEOUS DISPERSION OF URETHAN ACRYLATE ENTCOPOLYMERS AND STABLE AQUEOUS DISPERSION THUS OBTAINED. |
| AU597257B2 (en) * | 1985-05-17 | 1990-05-31 | M And T Chemicals Inc. | Aqueous alkaline developable, uv curable urethane acrylate compounds and compositions useful for forming solder mask coatings |
-
1987
- 1987-11-03 CA CA000550900A patent/CA1332093C/en not_active Expired - Fee Related
- 1987-12-04 IT IT8722899A patent/IT1233418B/en active
- 1987-12-07 NL NL8702942A patent/NL190785C/en not_active IP Right Cessation
- 1987-12-07 DE DE3741385A patent/DE3741385C2/en not_active Expired - Fee Related
- 1987-12-08 BR BR8706609A patent/BR8706609A/en not_active IP Right Cessation
- 1987-12-08 MX MX009667A patent/MX168832B/en unknown
- 1987-12-08 FR FR878717087A patent/FR2607820B1/en not_active Expired - Lifetime
- 1987-12-08 CN CN87107321A patent/CN1031227C/en not_active Expired - Fee Related
- 1987-12-08 CH CH4773/87A patent/CH680622A5/de unknown
- 1987-12-08 GB GB8728631A patent/GB2199335B/en not_active Expired - Lifetime
- 1987-12-08 KR KR1019870014055A patent/KR910001523B1/en active IP Right Grant
-
1992
- 1992-06-12 SG SG611/92A patent/SG61192G/en unknown
- 1992-08-13 HK HK606/92A patent/HK60692A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| GB8728631D0 (en) | 1988-01-13 |
| SG61192G (en) | 1992-09-04 |
| IT8722899A0 (en) | 1987-12-04 |
| KR910001523B1 (en) | 1991-03-15 |
| CN87107321A (en) | 1988-06-22 |
| FR2607820B1 (en) | 1994-06-10 |
| CH680622A5 (en) | 1992-09-30 |
| NL8702942A (en) | 1988-07-01 |
| CN1031227C (en) | 1996-03-06 |
| BR8706609A (en) | 1988-07-19 |
| KR880014415A (en) | 1988-12-23 |
| DE3741385A1 (en) | 1988-06-09 |
| MX168832B (en) | 1993-06-10 |
| NL190785C (en) | 1994-08-16 |
| HK60692A (en) | 1992-08-21 |
| GB2199335A (en) | 1988-07-06 |
| NL190785B (en) | 1994-03-16 |
| FR2607820A1 (en) | 1988-06-10 |
| IT1233418B (en) | 1992-03-31 |
| DE3741385C2 (en) | 1996-06-05 |
| GB2199335B (en) | 1991-01-09 |
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