WO2003095507A1

WO2003095507A1 - Water-dilutable/dispersible radiation curable compositions

Info

Publication number: WO2003095507A1
Application number: PCT/EP2003/004865
Authority: WO
Inventors: Kong Chin Chew; Norazmi Alias
Original assignee: Ucb, S.A.
Priority date: 2002-05-10
Filing date: 2003-05-09
Publication date: 2003-11-20
Also published as: AU2003239855A1; TW200406433A

Abstract

The invention provides in one form a water-dilutable and/or dispersible radiation curable composition that is developable in aqueous alkaline solution and which comprises the reaction product of a (meth)acrylated polymeric binder containing acid group with a primary, or more preferably, a secondary amine containing compound of Formula (I), where R1 and R2 independently represent H or optionally substituted hydrocarbo, such as alkyl, aryl, cycloalkyl, arylalkyl, hydroxy alkyl, hydroxy aryl, hydroxy cycloalkyl and hydroxy cycloaryl. R1 and R2 may also contain, within them, the organo linkages such as (poly)amido, (poly)ester, (poly)urethane, (poly)urea, (poly)ether, and (poly)carbonate. A further requirement is that R1 and R2 must not both represent H at the same time.

Description

WATER-DILUTABLE / DISPERSIBLE RADIATION CURABLE COMPOSITIONS

Field of the invention

This invention relates to radiation curable compositions which can be diluted with (and /or dispersed in) water, and may be used as liquid photo-resist compositions for the fabrication of articles such as printed circuit boards. The radiation curable compositions are removable when they are not cured by an aqueous alkaline water. In a printed circuit board the circuitry images are defined by the cured composition area that remains after the alkaline removal of the uncured areas.

Background to the invention

Typically printed circuit boards are fabricated by applying a radiation curable coating to the copper surface of the board. A negative film of the desired circuit image is then applied to the curable coating and the film is exposed to a UV light source. After the coating is cured the printed circuit board is washed in an aqueous alkaline solution to remove the coating areas that were not exposed to the UV light source. The board is then etched to remove the uncoated copper regions. Other imagining techniques may be used. In addition to this use for forming printed circuit boards, these techniques can be used to form other surfaces such as printing plate surfaces. In this field radiation curable compositions are termed photo-resist compositions.

Photo-imageable compositions useful as photo-resists in forming printed circuit boards are taught in US Patent 3,953,309. The photo-imageable composition contains photo-polymerisable material to render it curable by irradiation, a photo-initiator system, and acid functional binder to allow for developing in alkaline solution. The presence of acid groups such as carboxylic acid in the photo-polymerisable material is necessary to make the photo-resist compositions developable in alkaline solution. The presence of the acid groups also allows the removal of the photo-cured composition, if required, by immersion in a second bath that is more alkaline than the developing bath solution. However, this requirement is a disadvantage if it is desired that the cured coating remains and the subsequent processing solutions are alkaline. In this case the photo-polymerised portions would be subjected to degradation in the highly alkaline solution like the ammoniacal etchants or metal plating solutions. Under these conditions, such photo-resist would be subjected to delamination and stripping. US Patent 4,943,516 teaches a photosensitive thermosetting composition containing a photosensitive polymer based on acid functional epoxy (meth)acιylates and a finely powdered epoxy compound useful in liquid photo-imageable solder mask. The composition described in this patent is excellent in chemical and thermal resistance but lacks fast drying. Typically a long drying time is required to produce a tack-free surface prior to contact copying to image the circuit pattern onto the photo-resist coating. Attempts to speed the tack-free time by using ovens is usually unsatisfactory. Long residence times in an oven make the photo-resist susceptible to picking up dust particles and this can produce micro-defects during the subsequent photo-imaging step.

FR 2,253,772 teaches a photo-polymerisable composition for lithographic plates or a photo-resist and it comprises an addition copolymer of maleic anhydride with vinyl or styrene monomers. This copolymer is then esterifled with an ethylenically unsaturated alcohol or a polyol which itself is partially esterifled with an unsaturated aliphatic acid. The unsaturated alcohol or polyol may contain alkoxy groups. The presence of water or alkaline sensitive groups such as alkoxy (ethoxy or methoxy) groups may improve the alkaline developability of the unpolymerised region of the photo-resist but also degrades the acid and alkaline resistance of the cured photo-resist in the subsequent acidic or alkaline etching solution. In addition, the incomplete opening of the anhydride (60-80% reacted) will subsequently reduce the alkaline developability of the photo-resist.

US Patent 5,296,334 teaches a polymerisable composition for use as a solder mask. This composition contains a binder polymer made from the esterification product of a styrene maleic anhydride copolymer with less than 15% free anhydride, with at least 50% of the available anhydride groups esterifled with a hydroxy alkyl (meth)acrylate, and at least 0.1% of available anhydride groups being esterifled with monohydric alcohols. It also contains a multifunctional (meth)acrylate monomer and a multifunctional epoxide. The use of high concentrations of (meth)acrylate monomers such as TMPTA, TPGDA or DPHA, increases the UV reactivity of the photo-resist. However, this generally adds to the tackiness of the photo-resist composition.

US Patent 4,370,403 teaches a polymerisable composition based on (a) reaction product of styrene maleic anhydride copolymer and 2-hydroxyethyl acrylate, (b) other ethylenically unsaturated compounds and (c) photo-initiator. US Patent 4,722,947 describes a radiation curable polymer based on reaction of styrene/maleic anhydride copolymer with hydroxy alkyl acrylate and another alcohol, such as an arylalkyl monohydric alcohol. The presence of an alcohol with no acrylate unsaturation decreases the UV reactivity and the resultant UV cross-linking of the coating. This leads also to a reduction in the chemical resistance of the photo-resist in subsequent alkaline or acidic processing.

US Patent 4,723,857 describes the photo-imageable compositions containing styrene/maleic anhydride copolymer partially esterifled with methanol and isopropanol. The resultant polymer is acidic in nature but contains no acrylate unsaturation to render it photo-polymerisable under ultraviolet irradiation. It is desirable that photo-resist compositions have short tack-free times and relatively short times for dissolution in alkaline solution.

All the above examples are solvent-based, and it is common practice in the industry today to use such materials. Due to tighter restrictions regarding volatile organic content (VOC) emissions to the environment, however, it is essential that the use of solvents be minimised or be completely eliminated in liquid photoresist compositions.

WO 98/457755 (Advanced Coatings International) describes certain waterborne dispersions of aliphatic urethane acrylate oligomers for use in making photo-resists. The compositions require the addition of based such as ammonia, morpholine and potassium hydroxide to neutralize the acid groups to render the polymeric binder water soluble.

US Patents 5,691,006 and 5,501,942 and EP 493317 (Ciba) teaches the use of commercially available solid carboxylic acid containing acrylic copolymers such as Carboset 525, XL37 and 531 which are neutralized with ammonia or amines before dispersion in water. Due to the high Tg of the binders, solvents are still required to dissolve the resins prior to neutralization.

US Patent 5,741,621 and EP 747769/A2 (Du Pont) describe process for using photoimageable films prepared for aqueous photoimageable liquid emulsions. Polymer based on methyl methacrylate/ethyl acrylate/styrene/methacrylic acid prepared by emulsion polymerisation using persulfate initiator (based on NH₄ ⁺ or Na⁺ salts) is preferred to give stable polymer emulsion. It is thought that the charged sulfate group introduced onto the surface of emulsion particles may serve to stabilise the resulting emulsion by raising the electrical potential of the emulsion particles. US patent 5,045,435 describes waterbome and aqueous developable coating composition. The examples describe usage of commercially available latex copolymer composition such as Neocryl CL-340, Acrysol 1-2074 and Neocryl BT-175 as the base polymer. Neutralization is carried out with ammonia. A tack free film is achieved after drying at 70 Celsius for 10 minutes.

US Patent 5,364,737 describes the use of an associative thickener based on a polyether polyurethane (such as Henkel's DSX-1514) to stabilize emulsions. This allows lesser neutralization with amines or ammonia, and increases the chemical resistance of the photoresist. The process for preparation of the waterbome photoresist contains two parts, one hydrophobic phase containing (meth)acrylate monomers, initiators, antoixidants and dyes, and another aqueous phase containing the acidic acrylic copolymer (Neocryl CL-340), antifoaming agent (Byk 033), neutralizers (DMAMP-90, and AMP-95) and associative thickener (DSX-1514) in water. The hydrophobic phase and aqueous phase are blended to form a hydrophobic phase in water emulsion. Surface tension modifier such as Fluorad FC170-C and up to 5% coalescing solvent such as methoxy propyl acetate are used. Final composition has 20-40% solid, and typically 3-20% (meth)acrylate monomers mainly ethoxylated type like TMP(EO)TA.

The use of polydimethoxysiloxane (PDMS) such as Dow Coming's Q4-3667 hydroxyl terminated PDMS in the waterbome composition is described in US Patent 5,387,494. It is claimed that PDMS increases the tack-free of the surface after drying.

The use of amino acrylate for neutralization, such as dimethylaminoethyl acrylate, is described in US patent 5,393,643. Tertiary aminoacrylates such as N,N- diethylaminoethyl acrylate, N,N-dimethylaminoetyhyl (meth) acrylate, and N,N- dimethylaminopropyl (meth) acrylate are also used. It is claimed that amino acrylates eliminate developing residue and etch retardation due to the higher solubility of the uncured resist in alkaline solution. It also gives a faster drying time and exposure time, and fewer pinholes, and finally faster stripping of the cured portion of the resist.

US Patent 5,942,371 describes an acid containing acrylate oligomer neutralized with ammonia, amine or an organic base to make the oligomer soluble or dispersible in water. Epoxy acrylate further acidified with anhydride is the preferred oligomer. The oligomer can contain up to 15% by weight of solvent. Acid value of the COOH- containing oligomer prior to neutralization must be at least 25 mg KOH/gm but higher than 60 mg KOH/gm is preferred. This composition was tested for solder mask applications and was reported to give good results.

All the above examples describe the addition of an amine containing compound to neutralize the acid functionalities of the main polymeric binders. The disadvantage of such an approach is that these amines are commonly of low molecular weight and can be volatile. This leads to their release to the environment during drying in the oven, giving bad odours and may harm anyone working nearby if no proper ventilation system is available. Another potential problem is the change in the rheology (eg viscosity) and other properties of the composition due to the addition of such amines. Although the problem of volatility can be avoided by using a crosslinkable amino acrylate as described in US Patent 5,393,643, the addition of the amino acrylate may affect the desired property of the composition after curing. Furthermore, due to the change in rheology of the composition upon the addition of the amino acrylate, it may be necessary to add other components to bring the composition back to a property suitable for application.

Summary of the invention

The present invention provides in one form a water-dilutable and/or dispersible radiation curable composition that is developable in aqueous alkaline solution and which comprises the reaction product of a (meth)acrylated polymeric binder containing acid group with a primary, or more preferably, a secondary amine containing compound of Formula I,

HN R₂

Formula I where

Ri and R₂ independently represent H or optionally substituted hydrocarbo, such as alkyl, aryl, cycloalkyl, arylalkyl, hydroxy alkyl, hydroxy aryl, hydroxy cycloalkyl and hydroxy cycloaryl. Ri and R₂ may also contain, within them, the organo linkages such as (poly)amido, (poly)ester, (poly)urethane, (polyjurea, (poly)ether, and (poly)carbonate. A further requirement is that Ri and R₂ must not both represent H at the same time. A radiation curable composition made from the reaction of the compounds of Formula I with an unsaturated carboxylic acid functionalised copolymer made via (meth)acrylic polymerisation of Formula IA:

Formula IA Where X is H or CH3 and is preferably CH3, Ri and R₂ independently represent optionally substituted hydrocarbo, hydrocarbo ether; poly(hydrocarbo ether); hydrocarbo ester, poly(hydrocarbo ester) and poly(hydrocarbo ether hydrocarbo ester); preferably optionally substituted alkyl, aryl, cycloalkyl, or arylalkyl and where the molecular weight of the copolymer is preferably 1000-100000, the acid value is preferably 50-300 mgKOH/g and the unsaturated functionality is 1-100; m and n are 1 or greater than 1.

Preferably, the reaction of the amine-containing compound of formula I with the unsaturated carboxylic acid functionalised copolymer of formula IA is partial and provides a reaction product containing carboxylic group, (meth)acrylate functionality and amine functionality.

The acid containing (meth)acrylated polymeric binder can be a composition which comprises of:

(a) a copolymer which is a partial esterification product of a styrene maleic anhydride copolymer with at least two hydroxy containing compounds of Formula II,

HO— X -TT TD-

Formula II where p is 0 or 1 ; n is an integer from 1 to 7;

R^a, R^b and R^c are independently H or methyl, preferably R^a is methyl or H and R^b and R^c are both H (i.e. Formula I denotes a (meth)acrylate);

W represents a divalent optionally substituted organo linking moiety preferably selected from a group consisting of one or more optionally substituted hydrocarbo, hydrocarbo ether; poly(hydrocarbo ether); hydrocarbo ester, poly (hydrocarbo ester) and poly(hydrocarbo ether hydrocarbo ester); more preferably selected from the group consisting of: alkylene, alkylene ether, polyether, polyester, alkylene ester and polyether polyester;

X represents a (n+1) valent optionally substituted organo linking moiety preferably selected from a group consisting of one or more optionally substituted hydrocarbo, hydrocarbo ether; poly(hydrocarbo ether); hydrocarbo ester, poly(hydrocarbo ester) and poly(hydrocarbo ether hydrocarbo ester); more preferably selected from the group consisting of: alkylene, alkylene ether, polyether, polyester, alkylene ester and polyether polyester;

Y is oxo (-0-), imino (-NH-) or hydrocarbo substituted imino (-NRi-, where Ri is hydrocarbo, preferably alkyl); (b) optionally, a partial esterification product of a styrene maleic anhydride copolymer with one or more hydroxyl containing compounds of the following formulae:

HO_N ,R₂

R₄- _S

and/or R2— (NHC=0)m— R4— OH

(i.e. either substituent may be attached to either the N or C atoms of the N- substituted carbamoyl moiety); such that R₂ and R3 independently represent H or optionally substituted hydrocarbo, preferably optionally substituted alkyl, aryl, cycloalkyl, or arylalkyl; 4 independently in each case represents a direct bond (i.e. where the OH is attached to the nitrogen or carbonyl) or a divalent optionally substituted organo linking moiety, preferably optionally substituted hydrocarbo; more preferably optionally substituted alkylene, arylene, cycloalkylene, or arylalkylene; and m is 1 or greater.

Alternatively, the acid containing (meth) acrylate polymeric binder may also be of a composition which comprises of:

(a) a blend of copolymers which are a partial esteriflcation product of a styrene maleic anhydride copolymer with compounds of Formula III;

Formula III where r is 0 or 1 ; s is an integer from 1 to 7;

R^a', R^b' and R^c' are independently H or methyl, preferably R^a' is methyl or H and R^b' and R^c' are H (i.e. Formula II denotes a (meth)acrylate) when Y is oxo;

X' represents a (n+1) valent optionally substituted organo linking moiety preferably selected from a group consisting of one or more optionally substituted hydrocarbo, hydrocarbo ether; poly(hydrocarbo ether); hydrocarbo ester, poly (hydrocarbo ester) and poly(hydrocarbo ether hydrocarbo ester); more preferably selected from the group consisting of: alkylene, alkylene ether, polyether, polyester, alkylene ester and polyether polyester;

W represents a divalent optionally substituted organo linking moiety preferably selected from a group consisting of one or more optionally substituted hydrocarbo, hydrocarbo ether; poly(hydrocarbo ether); hydrocarbo ester, poly(hydrocarbo ester) and poly (hydrocarbo ether hydrocarbo ester); more preferably selected from the group consisting of: alkylene, alkylene ether, polyether, polyester, alkylene ester and polyether polyester;

Y" is oxo (-0-), imino (-NH-) or hydrocarbo substituted imino (-NR'i-, where R'ι is hydrocarbo, preferably alkyl); (b) optionally a partial esteriflcation product of a styrene maleic anhydride copolymer with one or more hydroxyl containing compounds of the following formulae: HO

R'₄-N,

R',

and/or R2— (NHC=0)t— R4— OH

(i.e. either substituent may be attached to either the N or C atoms of the N- substituted carbamoyl moiety); such that

R'2 and R'₃ independently represent H or optionally substituted hydrocarbo, preferably optionally substituted alkyl, aryl, cycloalkyl, or arylalkyl

R' independently in each case represents a direct bond (i.e. where the OH is attached to the nitrogen or carbonyl) or a divalent optionally substituted organo linking moiety, preferably optionally substituted hydrocarbo; more preferably optionally substituted alkylene, arylene, cycloalkylene, or arylalkylene; and t is 1 or greater.

Alternatively, unsaturated carboxylic acid containing acrylic polymer derived from the reaction of (I) carboxylic acid containing acrylic polymer and unsaturation- containing epoxide, or (II) epoxide containing acrylic polymer and acrylic acid, or methacrylic acid or (meth)acrylic acid esters. An example is the commercially available unsaturated carboxylic acid containing acrylic polymer, Cyclomer-P ACA series from Daicel Chemical, Japan. The preferred molecular weight of such binders is 1000-100,000; the preferred acid value is 50-2000 mgKOH/g; the preferred functionality is between 5 and 50.

Detailed description of the invention

The copolymer of the present invention is prepared by the Michael addition of a primary or secondary amine to a (meth) acrylate group of a solvent-based acid containing (meth)acrylated polymeric binder.

An example of the type of product that is obtained from the present invention is illustrated in the chemical reaction below, which is the reaction between a half-ester of a sryrene-maleic anhydride copolymer and monomethylethanolamine.

where n and M are 1 or greater than 1 where X = H or CH₃

(it is not a preference to use hydroxylated amines in this case, unlike ipd256.93, since no further reaction is intended after the michael addition.)

An example of acid containing (meth)acιylated polymeric binder include commercially available acrylic resins such as Cyclomer-P ACA250 (copolymer of methyl methacrylate/methacrylic acid, functionalized with 3, 4- epoxycyclohexylmethacrylate, product of Daicel Chemical, Japan). Another example of the acid containing (meth)acrylated polymeric binder is the copolymer preferably prepared by esteriflcation of at least 50 mole % of the free anhydride groups in the styrene maleic anhydride copolymer with hydroxy alkyl (meth)acrylates, and less than 50 mole % of the free anhydride groups with caprolactone - or alkoxy - containing hydroxy (meth)acrylates. In order to assure nearly all of anhydride is opened, the reaction is preferably carried out with an excess of hydroxyl groups.

The reaction of the anhydride and hydroxyl monomers is usually carried out in the presence of organic solvents. TyP^ical solvents used for liquid photo-resist systems are propylene glycol mono methyl ether, propylene glycol mono methyl ether acetate, butyl ether glycol acetate, and butyl carbitol acetate. The solvent is typically first charged into a glass vessel and heated slowly to 60°C. At this temperature a styrene maleic anhydride copolymer may be added along with polymerisation inhibitors to prevent thermal polymerisation of the (meth)acrylate unsaturation. Typ^ical inhibitors used are hydroquinone and its derivatives triphenyl antimony, and trionyl phenyl phosphite. The hydroxyl (meth)acrylate monomer may then be added into the copolymer solution in the vessel. The temperature can then be increased to 90°C to 100°C, and held until nearly all the anhydride groups are opened. Complete reaction can be established when the acid value of the reaction product nearly equals the acid value of the semi-ester.

Two different methods may be used to prepare the copolymer. The first is by reacting the styrene maleic anhydride copolymer separately with two different types of hydroxyl (meth)acrylates, and then blending these two different copolymers such that the mixture contains partial esteriflcation products of the styrene maleic anhydride with two different hydroxyl (meth) acrylates. The second method is to react the styrene maleic anhydride copolymer simultaneously with two different hydroxyl (meth) acrylates. A typical structure of a copolymer of the invention is:

such that R is a divalent alkyl ester, divalent alkyl ether moiety, and/or

OR₄ N(R₃) R₂0-

(i.e. either divalent substituent may be attached to either the N or C atoms of the N- substituted carbamoyl moiety) where R2 and R3 independently represent optionally substituted hydrocarbo, preferably optnioally substituted alkyl, aryl, cycloalkyl, or arylalkyl;

Ri independently in each case represents a direct bond or a divalent optionally substituted organo linking moiety, preferably optionally substituted hydrocarbo; more preferably optionally substituted alkylene, arylene, cycloalkylene, or arylalkylene e, f, g and/or h preferably independently represent 1 or greater, more preferably an integer from 1 to 7 (inclusive); and k and 1 independently represent 0 or an integer from 1 to 7 (inclusive). m is 1 or greater, preferably 1 ;

More preferably when 1 is 0 then R is

or

— OR₄ N(R₃) — R₂

where,

R2 and R3 independently represent H or optionally substituted hydrocarbo, preferably optionally substituted alkyl, aryl, cycloalkyl, or arylalkyl

Rt independently in each case represents a direct bond or a divalent optionally substituted organo linking moiety, preferably optionally substituted hydrocarbo; more preferably optionally substituted alkylene, arylene, cycloalkylene, or arylalkylene. More preferably when 1 is from 1 to 7 then R is a divalent alkyl ester or divalent alkyl ether moiety.

Styrene maleic anhydride copolymers are commercially available resins such as SMA resins from Elf Atochem, and Leumal resins from Leuna Harze GmbH. The preferred styrene maleic anhydride copolymer resins has molecular weight between 1000 and 30,000 and a mole ratio of styrene to maleic anhydride in the respective range of about (1 to 1) to about (3 to 1).

Examples of suitable hydroxyl alkyl (meth) acrylates for partial esteriflcation with the styrene maleic anhydride copolymer are 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, hydroxyl propyl methacrylate, n-methylol methacrylamide and n-methylol acrylamide. Examples of hydroxyl monomers with more than one (meth) acrylate groups are ditrimethylopropane triacrylate, pentaerythritol triacrylate, and dipentaerythritol pentaacrylate. (Meth)acrylate monomers with functionality greater than one are preferred when very high photosensitivity of the photo-resist composition is desired.

Examples of caprolactone containing hydroxyl (meth) acrylate are commercially available from Union Carbide Corporation under the trade names Tone M-100 and M-200.

Examples of alkoxy-containing hydroxyl (meth)acrylate are polyethyleneglycol monoacrylate, polyethyleneglycol monomethacrylate, polypropyleneglycol monoacrylate, polypropyleneglycol monomethacrylate, and mixtures of ethylene and propylene glycol such as polyalkyleneglycol monomethacrylate. Examples of these are available from Inspec under the trade names Bisomer PEM63P and PPM63E. It is not essential that all the maleic anhydride rings of the copolymer are reacted with (meth) acrylate monomers. For example, minor amounts of amine or hydroxyl containing moieties may be used to form non (meth)acrylate amide or ester side chains respectively.

These side chains may influence the overall solubility of the copolymer composition, especially in dilute alkaline solutions. An example of a possible non (meth) acrylate side chain is methoxy polyethyleneglycol. Another example is an alkanolamine of formula HONR²R³ as well as an amido alcohol of formula HOR⁴(NHCO)_mR²; where R² and/or R³ may be independently alkyl, aryl, cycloalkyl, arylalkyl and m' is 1 or greater.

The reaction of the (meth)acrylated polymeric binder with the amine is usually carried out in the presence of polymerisation inhibitors to prevent thermal polymerisation of the (meth) acrylate unsaturation. TyP^ical inhibitors used are hydroquinone and its derivatives triphenyl antimony, and trisnonyl phenyl phosphite. The inhibitors are usually added before the reaction is started. The amine is added dropwise to the polymeric binder, causing an exothermic temperature rise. The temperature is typically maintained below 50 Celsius during the addition. Upon completion of the exotherm, the reaction is maintained at 45 Celsius for about two hours before it is stopped.

The amount of amine compound to be reacted to the (meth)acrylated polymeric binder is between 0.1 and 0.9 amine equivalent for each double bond equivalent of the (meth)acrylate functionality.

The terms Optional substituent' and /or Optionally substituted' as used herein (unless followed by a list of other substituents) signifies the one or more of following groups (or substitution by these groups): carboxy, sulpho, formyl, hydroxy, amino, imino, nitrilo, mercapto, cyano, nitro, methyl, methoxy and/or combinations thereof. These optional groups include all chemically possible combinations in the same moiety of a plurality (preferably two) of the aforementioned groups (e.g. amino and sulphonyl if directly attached to each other represent a sulphamoyl group). Preferred optional substituents comprise: carboxy, sulpho, hydroxy, amino, mercapto, cyano, methyl and /or methoxy.

The synonymous terms 'organic substituent' and "organic group" as used herein (also abbreviated herein to "organo") denote any univalent or multivalent moiety (optionally attached to one or more other moieties) which comprises one or more carbon atoms and optionally one or more other heteroatoms. Organic groups may comprise organoheteryl groups (also known as organoelement groups) which comprise univalent groups containing carbon, which are thus organic, but which have their free valence at an atom other than carbon (for example organothio groups). Organic groups may alternatively or additionally comprise organyl groups which comprise any organic substituent group, regardless of functional type, having one free valence at a carbon atom. Organic groups may also comprise heterocyclyl groups which comprise univalent groups formed by removing a hydrogen atom from any ring atom of a heterocyclic compound: (a cyclic compound having as ring members atoms of at least two different elements, in this case one being carbon). Preferably the non carbon atoms in an organic group may be selected from: hydrogen, halo, phosphorus, nitrogen, oxygen and/or sulphur, more preferably from hydrogen, nitrogen, oxygen and/or sulphur.

The term 'hydrocarbo group' as used herein is a sub-set of a organic group and denotes any univalent or multivalent moiety (optionally attached to one or more other moieties) which consists of one or more hydrogen atoms and one or more carbon atoms. Hydrocarbo groups may comprise one or more of the following groups. Hydrocarbyl groups comprise univalent groups formed by removing a hydrogen atom from a hydrocarbon. Hydrocarbylene groups comprise divalent groups formed by removing two hydrogen atoms from a hydrocarbon the free valencies of which are not engaged in a double bond. Hydrocarbylidene groups comprise divalent groups (represented by

formed by removing two hydrogen atoms from the same carbon atom of a hydrocarbon, the free valencies of which are engaged in a double bond; Hydrocarbylidyne groups comprise trivalent groups (represented by "RC≡"), formed by removing three hydrogen atoms from the same carbon atom of a hydrocarbon the free valencies of which are engaged in a triple bond. Hydrocarbo groups may also comprise any saturated, unsaturated double and/or triple bonds (e.g. alkenyl, and/or alkynyl respectively) and/or aromatic groups (e.g. aryl) and where indicated may be substituted with other functional groups.

Most preferably organic groups comprise one or more of the following carbon containing moieties: alkyl, alkoxy, alkanoyl, carboxy, carbonyl, formyl and/or combinations thereof; optionally in combination with one or more of the following heteroatom containing moieties: oxy, thio, sulphinyl, sulphonyl, amino, imino, nitrilo and/or combinations thereof. Organic groups include all chemically possible combinations in the same moiety of a plurality (preferably two) of the aforementioned carbon containing and /or heteroatom moieties (e.g. alkoxy and carbonyl if directly attached to each other represent an alkoxycarbonyl group): The term 'alkyl' or its equivalent (e.g. 'alk') as used herein may be readily replaced, where appropriate and unless the context clearly indicates otherwise, by terms encompassing any other hydrocarbo group such as those described herein. Any substituent, group or moiety mentioned herein refers to a monovalent species unless otherwise stated or the context clearly indicates otherwise (e.g. an alkylene moiety may comprise a bivalent group linked two other moieties). A group, which comprises a chain of three or more atoms signifies a group in which the chain wholly or in part may be linear, branched and/or form a ring (including spiro and /or fused rings). The total number of certain atoms may be specified for certain substituents for example C_._xorgano, signifies an organic group having from 1 to x carbon atoms. In any of the formulae herein, if one or more substituents are not indicated as attached to any particular atom on the moiety, the substituent may replace any hydrogen atom attached to another atom and/or may be located at any available position on the moiety which is chemically suitable and/or where there is a free valence (which may be indicated in the formulae herein by an arrow). Parts of some chemical terms used herein are given in parentheses and unless the context dictates otherwise (e.g. parentheses in an IUAPC name), these denote that the parenthetic moiety is optional. For example as used herein the term "(meth)acrylate" denotes both methacrylate and acrylate.

Some of the organic groups such as hydrocarbo, alkyl etc listed herein do not have the number of carbon atoms specified in which case preferably such groups comprise from 1 to 36 carbon atoms, more preferably from 1 to 18 carbon atoms. It is particularly preferred that the number of carbon atoms in such groups is from 1 to 10 inclusive.

Unless the context clearly indicates otherwise, as used herein plural forms of the terms herein are to be construed as including the singular form and vice versa. For example the terms "group" and "functionality" designates respectively one single group or several groups and one single functionality or several functionalities. The term 'effective' (for example with reference to the process, uses, products, materials, compounds, monomers, oligomers, polymer precursors and/or polymers of the present invention) will be understood to refer to those ingredients which if used in the correct manner provide the required properties to the material, compound, composition, monomer, oligomer, polymer precursor and/or polymer to which they are added and /or incorporated in any one or more of the uses and /or applications described herein. As used herein the term "suitable" denotes that a functional group is compatible with producing an effective product. The substituents on the repeating unit may be selected to improve the compatibility of the materials with the polymers and/or resins in which they may be formulated and/or incorporated to form an effective material. Thus, the size and length of the substituents may be selected to optimise the physical entanglement or interlocation with the resin or they may or may not comprise other reactive entities capable of chemically reacting and/or cross-linking with such other resins. Certain moieties, species, groups, repeat units, compounds, oligomers, polymers, materials, mixtures, compositions and/or formulations which comprise some or all of the invention as described herein may exist as one or more stereoisomers (such as enantiomers, diastereoisomers, geometric isomers, tautomers and /or conformers), salts, zwitterions, complexes (such as chelates, clathrates, crown compounds, cyptands / cryptades, inclusion compounds, intercalation compounds, interstitial compounds, ligand complexes, non-stoichiometric complexes, organometallic complexes, π-adducts, solvates and/or hydrates); isotopically substituted forms, polymeric configurations [such as homo or copolymers, random, graft or block polymers, linear or branched polymers (e.g. star and/or side branched polymers), hyperbranched polymers and/or dendritic macromolecules (such as those of the type described in WO 93/ 17060), cross-linked and/or networked polymers, polymers obtainable from di and/or tri-valent repeat units, dendrimers, polymers of different tacticity (e.g. isotactic, syndiotactic or atactic polymers)]; polymorphs [ such as interstitial forms, crystalline forms, amorphous forms, phases and/or solid solutions] combinations thereof where possible and /or mixtures thereof. The present invention comprises all such forms which are effective. It Is appreciated that certain features of the invention, which are for clarity described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely various features of the invention, which are for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

The term "comprising" as used herein will be understood to mean that the list following is non-exhaustive and may or may not include any other additional suitable items, for example one or more further feature(s), component(s), ingredient(s) and /or substituent(s) as appropriate.

In some embodiments, the acid containing (meth)acrylated polymeric binder can be a composition which comprises of:

(a) a copolymer which is a partial esteriflcation product of a styrene maleic anhydride copolymer with at least two hydroxy containing compounds of Formula Ila,

Formula Ila

where p is 0 or 1 (i.e. when p is 0 then Y is directly attached to the carbonyl group); n is an integer from 1 to 7;

R^a, R^b and R^c are independently H or methyl, preferably R^a is methyl or H and R and R^c are both H (i.e. Formula I denotes a (meth) acrylate);

X and W independently represent a divalent optionally substituted organo linking moiety preferably selected from a group consisting of one or more optionally substituted hydrocarbo, hydrocarbo ether; poly(hydrocarbo ether); hydrocarbo ester, poly (hydrocarbo ester) and poly (hydrocarbo ether hydrocarbo ester); more preferably selected from the group consisting of: alkylene, alkylene ether, polyether, polyester, alkylene ester and polyether polyester;

Y is oxo (-0-), imino (-NH-) or hydrocarbo substituted imino (-NRi-, where Ri is hydrocarbo, preferably alkyl);

Further aspects of the present invention are described in the claims herein.

Descriptions of preferred embodiment

The invention will be described by reference to the following examples of preferred embodiments which are non-limiting.

Example 1

This Example illustrates the preparation of copolymer used in compositions according to the present invention.

The amount of 195.4 grams of the styrene maleic anhydride copolymer, SMA 3000 (having a molecular weight of 10,000 and styrene to maleic anhydride mole ratio of 3 to 1 and available commercially from Elf Atochem under the SMA 3000 trade designation) and 180 grams of propylene glycol methyl ether acetate were charged to a stirred one litre three-neck glass vessel and heated to 85-90°C to dissolve the copolymer. To this solution 0.27 grams of hydroquinone and 0.27 grams of triphenyl stibene inhibitors were added. A mixture of 75.9 grams of hydroxyethyl methacrylate and 0.54 grams of 4-ethyl morpholine was slowly added into the reaction vessel over a period of one hour. The reaction mixture was held at 90°C for eight to twenty four hours until the total acid value equaled the theoretical partial acid value, or until the total acid value stopped reducing. The reaction mixture was post-stabilised with 0.22 grams of trinonylphenyl phosphite inhibitor. The final acid value of the copolymer ester was 1 17mg KOH/gm and its non -volatile content was 60%. This copolymer semi-ester was designated A. Example 2

This Example illustrates the preparation of copolymer compositions according to the present invention.

The amount of 166 grams of copolymer A was charged into a 400ml beaker, followed by 20g monomethylethanolamine (MMEA). The mixture is stirred for 30 minutes where an exothermic temperature rise is observed. A soft material is formed, physically separated from the solvent. This amine adduct is designated copolymer B.

The amount of 299 grams of copolymer A was charged into a 500ml vessel and is stirred continuously at room temperature. 39.9 g diethylamine (DEA) is then added slowly over 20 minutes. An exothermic temperature rise is observed, and controlled to below 50 Celsius. When the exo therm is over, the reaction temperature is maintained at 45 Celsius for 2h to give the amine-modified copolymer designated as copolymer C.

The amount of 500 grams of commercially available acrylic copolymer Cyclomer-P ACA250 (copolymer of methyl methacrylate/methacrylic acid, functionalized with 3, 4- epoxycyclohexylmethacrylate, product of Daicel Chemical, Japan) was charged into a 1000ml glass vessel, and is continuously stirred at room temperature. 38 g of diethylamine (DEA) is added dropwise over 20 minutes. The exothermic temperature rise is maintained not to exceed 50 Celcius. When the exotherm is over, the product is allowed to mature at 45 Celcius for 2h. This amine- modified copolymer is designated copolymer D.

Example 3

This example illustrates the water dilutability of the copolymers B, C and D.

Into a 50 ml beaker, charge 20 g of copolymer B. Under continuous agitation, 6 g of deionised water was added. A homogeneous mixture was formed, designated as mixture E.

Into a 50 ml beaker was charged 20 g of copolymer C. Under continuous agitation, 5 g of deionised water was added to give a homogeneous mixture designated as mixture F.

Into a 50 ml beaker was charged 20 g of copolymer D. Under continuous agitation, add 13 g of deionised water. A homogeneous mixture was formed, designated as mixture G.

Example 4 This example evaluates the tack-free and alkaline developability of the water diluted mixtures E, F and G.

Each of the copolymers was evaluated for tack-free and alkaline solubility in 1% Na₂C0₃ solution by the following methods.

Time to tack-free.

A copolymer was coated onto a cleaned copper board using a #16 wire drawdown bar to give an approximately 20-30 μm thick wet film. The coated board was then placed in an 80°C oven. The tackiness was checked at 5 minute intervals commencing immediately after the board was removed from the oven. The copolymer film was rated as tack-free if no finger marks were left on the film surface.

Alkaline solubility.

The solubility of the copolymer in 1% Na₂C0₃ solution at 30°C was determined using a spraying unit containing the alkaline solution. The amount of copolymer left on the board was checked after periodic spraying with the alkaline solution at intervals of 30 seconds.

Results of the tack-free and alkaline solubility are in given the following table. Results for copolymer A are included to show the improvements obtained from the present invention:

It can be seen that the embodiments of copolymers B, C and D are beneficial in conferring water dilutable properties, as shown in Example 3, in preparing the mixtures E, F and G. Note that copolymer A and the commercial resin Cyclomer-P ACA250 are not water dilutable by themselves. A further advantage is that the present embodiment, as shown by mixtures E and F, has improved the tack free property and alkaline solubility of the parent copolymer A.

Claims

1. A radiation curable composition which is dilutable and/or dispersable in aqueous solution and which comprises a reaction product of a (meth) acrylated polymeric binder containing acid group with a primary or secondary amine- containing compound of Formula I, the amine group(s) of the amine-containing compound being reacted with ethylenic group(s) of the (meth)acrylated compound by an Michael's addition type reaction, and formula I is:

Formula I Where Ri and R2 independently represent H or optionally substituted hydrocarbo, preferably optionally substituted alkyl, aryl, cycloalkyl, arylalkyl, hydroxy alkyl, hydroxy aryl, hydroxy cycloalkyl and hydroxy cycloaryl and Ri and R₂ may optionally contain organo linkages moiety selected from a group consisting of (poly)amido, (poly)ester, (poly)urethane, (poly)urea, (poly)ether, and (poly)carbonate provided that Ri and R₂ must not be H at the same time.

2. A radiation curable composition as claimed in claim 1, wherein the composition is made from the reaction of the primary or secundary amine- containing compound of Formula I with an unsaturated carboxylic acid functionalised copolymer of Formula IA:

Formula IA Where X is H or CH₃, Ri and R₂ independently represent optionally substituted hydrocarbo, hydrocarbo ether; poly(hydrocarbo ether); hydrocarbo ester, poly(hydrocarbo ester) and poly(hydrocarbo ether hydrocarbo ester); preferably optionally substituted alkyl, aryl, cycloalkyl, or arylalkyl and where the molecular weight of the copolymer is preferably 1000-100000, the acid value is preferably 50- 300 mgKOH/g and the unsaturated functionality is 1-100; m and n are 1 or greater than 1.

3. A radiation curable composition as claimed in claim 2, wherein the reaction of the amine-containing compound of formula I with the unsaturated carboxylic acid functionalised copolymer of formula IA is partial and provides a reaction product containing carboxylic group, (meth)acrylate functionality and amine functionality.

4. A radiation curable composition as claimed in any preceding claim wherein the (meth)acrylated polymeric binder containing acid group comprises a copolymer which is a partial esteriflcation product of a styrene maleic anhydride copolymer with at least one hydroxy containing compound of Formula II,

Formula II Where p is 0 or 1 , n is an integer from 1 to 7, R^a, R^b and R^c are independently H or methyl, preferably R^a is methyl or H and R^b and R^c are both H; W represents a divalent optionally substituted organo linking moiety selected from a group consisting of one or more optionally substituted hydrocarbo, hydrocarbo ether; poly(hydrocarbo ether); hydrocarbo ester, poly(hydrocarbo ester) and poly(hydrocarbo ether hydrocarbo ester); more optionally selected from the group consisting of: alkylene, alkylene ether, polyether, polyester, alkylene ester and polyether polyester. Y is oxo (-0-), imino (-NH-) or hydrocarbo substituted imino (-NRi-, where Ri is hydrocarbo, preferably alkyl), X represents a (n+l)valent optionally substituted organo linking moiety selected from a group consisting of one or more optionally substituted hydrocarbo, hydrocarbo ether; poly (hydrocarbo ether); hydrocarbo ester, poly(hydrocarbo ester) and poly(hydrocarbo ether hydrocarbo ester); more optionally selected from the group consisting of: alkylene, alkylene ether, polyether, polyester, alkylene ester and polyether polyester. Y is oxo (-0-), imino (-NH-) or hydrocarbo substituted imino (-NRi-, where Ri is hydrocarbo, preferably alkyl), more preferably Y is O, p is 0, X is hydrocarbo, R is methyl or H and R^b and R^c are both H.

5. A radiation curable composition as claimed in claim 4 wherein the

(meth)acrylated polymeric binder containing acid group comprises of a partial esteriflcation product of a styrene maleic anhydride copolymer with one or more hydroxyl containing compounds of the following formulae:

HO_s R₂

R₄- _N R₃ and/or R2— (NHC=0)m— R4— OH

where R₂ and R3 independently represent H or optionally substituted hydrocarbo, preferably optionally substituted alkyl, aryl, cycloalkyl, or arylalkyl, i independently in each formulae represents a direct bond or a divalent optionally substituted organo linking moiety, preferably optionally substituted hydrocarbo; more preferably optionally substituted alkylene, arylene, cycloalkylene, or arylalkylene; and m is 1 or greater than 1.

6. A radiation curable composition as claimed in any preceding claim wherein the (meth)acrylated polymeric binder containing acid group comprises of a blend of copolymers which are a partial esteriflcation product of a styrene maleic anhydride copolymer with at least two different hydroxy containing compounds, each being of Formula III,

Formula III where r is 0 or 1, s is an integer from 1 to 7, R^a', R^b' and R^c' are independently H or methyl, preferably R^a' is methyl or H and R^b' and R^c' are H, W' represents a divalent optionally substituted organo linking moiety preferably selected from a group consisting of one or more optionally substituted hydrocarbo, hydrocarbo ether; poly(hydrocarbo ether); hydrocarbo ester, poly(hydrocarbo ester) and poly(hydrocarbo ether hydrocarbo ester); more preferably selected from the group consisting of: alkylene, alkylene ether, polyether, polyester, alkylene ester and polyether polyester, X represents a (s+1) valent optionally substituted organo linking moiety preferably selected from a group consisting of one or more optionally substituted hydrocarbo, hydrocarbo ether; poly(hydrocarbo ether); hydrocarbo ester, poly(hydrocarbo ester) and poly(hydrocarbo ether hydrocarbo ester); more preferably selected from the group consisting of: alkylene, alkylene ether, polyether, polyester, alkylene ester and polyether polyester,

Y' is oxo (-0-), imino (-NH-) or hydrocarbo substituted imino (-NR'i-, where R'ι is hydrocarbo, preferably alkyl), more preferably Y is O, p is 0, X is hydrocarbo, R^a is methyl or H and R^b and R^c are both H.

7. A radiation curable composition as claimed in claim 6 wherein the

(meth)acrylated polymeric binder containing acid group further comprises a partial esteriflcation product of a styrene maleic anhydride copolymer with one or more hydroxyl containing compounds of the following formulae:

HO R'₂

R'₄-N_N

and /or R₂— (NHC=0)t— R4— OH

R'₂ and R'₃ independently represent H or optionally substituted hydrocarbo, preferably optionally substituted alkyl, aryl, cycloalkyl, or arylalkyl, R'₄ independently in each case represents a direct bond or a divalent optionally substituted organo linking moiety, preferably optionally substituted hydrocarbo; more preferably optionally substituted alkylene, arylene, cycloalkylene, or arylalkylene; and t is 1 or greater.

8. A radiation curable composition as claimed in any preceding claim wherein at least 50 mole % of free anhydride groups in the styrene maleic anhydride copolymer are esterifled with hydroxy alkyl (meth)acrylates.

9. A radiation curable composition as claimed in claim 8 wherein less than 50 mole % of the free anhydride groups are reacted with caprolactone or alkoxy containing hydroxy (meth)acrylates, or with hydroxyl containing compounds of the following formulae:

HO_v R'₂

R'₄- _N

R', and/or R₂— (NHC=0)t— Ri— OH

R'₂ and R'₃ independently represent H or optionally substituted hydrocarbo, preferably optionally substituted alkyl, aryl, cycloalkyl, or arylalkyl, R' independently in each case represents a direct bond or a divalent optionally substituted organo linking moiety, preferably optionally substituted hydrocarbo; more preferably optionally substituted alkylene, arylene, cycloalkylene, or arylalkylene; and t is 1 or greater.

10. A radition curable composition as claimed in claim 8 wherein substantially all free anhydride groups are esterifled.

11. A process for making a radiation curable composition of partially esterifled styrene-maleic anhydride by: a. heating a solvent selected from a groups consisting of propylene glycol mono methyl ether, propylene glycol mono methyl ether acetate, butyl ether glycol acetate and butyl carbitol acetate to 60°C; b. adding a styrene maleic anhydride copolymer together with polymerisation inhibitors selected from a groups consisting of hydroquinone and its derivatives triphenyl antimony, and trinonyl phenyl phosphite to prevent thermal polymerisation of the (meth)acrylate unsaturation; c. reacting styrene maleic anhydride copolymer separately with two different types of hydroxyl (meth)acrylate; and d. blending the two different copolymers formed in step (a) wherein the mixture now formed contains partial esteriflcation products of styrene maleic anhydride with two different hydroxyl (meth)acrylate.

12. A process for making a radiation curable composition as claimed in claim 11 wherein the styrene maleic anhydride copolymer is prepared by reacting styrene maleic anhydride copolymer simultaneously with two different hydroxyl (meth)acrylates.

13. A process for making a water dilutable/dispersible radiation curable composition comprising the steps of: a. mixing styrene maleic anhydride copolymer with propylene glycol methyl ether acetate and heating the mixture; b. adding hydroquinone and triphenyl stibene inhibitors to the solution obtained in step (a); c. adding slowly hydroxyethyl methacrylate and 4-ethyl morpholine; d. maintaining the temperature of reaction mixture in step (c) at 90°C for eight to twenty four hours until the total acid value equaled the theoretical partial acid value, or until the total acid value stopped reducing; e. post-stabilisation of mixture in step (d) by the addition of trinonylphenyl phosphite inhibitor; f. adding monomethylethanolamine (MMEA) or diethylamine (DEA) to the mixture obtained in step (e); g. maintaining the reaction mixture at 45°C for two hours after the exotherm is over to give an amine-modified copolymer; h. dilute / disperse composition in (f) in water; and i. optionally separating the solid material obtained in step (f) from solvent.

14. A radiation curable composition as claimed in claim 6 or 7 wherein the partially esterifled styrene maleic anhydride copolymer is defined as:

where R is a divalent alkyl ester, divalent alkyl ether moiety, or

where R₂ and R3 independently represent optionally substituted hydrocarbo, preferably optionally substituted alkyl, aryl, cycloalkyl, or arylalkyl; Ri independently in each case represents a direct bond or a divalent optionally substituted organo linking moiety, preferably optionally substituted hydrocarbo; more preferably optionally substituted alkylene, arylene, cycloalkylene, or arylalkylene e, f, g and/or h preferably independently represent 1 or greater, more preferably an integer from 1 to 40 (inclusive); and k and 1 independently represent 0 or an integer from 1 to 7 (inclusive), m is 1 or greater, preferably 1.

15. A process for making a radiation curable composition as claimed in claim 14 wherein when 1 is 0, then R is:

where,

R₂ and R₃ independently represent H or optionally substituted hydrocarbo, preferably optionally substituted alkyl, aryl, cycloalkyl, or arylalkyl

I^t independently in each case represents a direct bond or a divalent optionally substituted organo linking moiety, preferably optionally substituted hydrocarbo; more preferably optionally substituted alkylene, arylene, cycloalkylene, or arylalkylene, more preferably when 1 is from 1 to 7 then R is a divalent alkyl ester or divalent alkyl ether moiety.

16. A process for making radiation curable composition as claimed in claim 14 wherein 1 is from 1 to 7 and R is a divalent alkyl ester or divalent alkyl ether moiety.

17. A process for making a radiation curable composition comprising the steps of: a) mixing a copolymer of methyl methacrylate/methacrylic acid, functionalized with 3, 4- epoxycyclohexylmethacrylate with diethylamine (DEA) slowly and maintaining the temperature of the reaction mixture to below 50°C; b) maintaining the reaction temperature at 45°C for two hours after the exotherm is over to give an amine modified copolymer. c) dilute or disperse (b) in water; and d) optionally separate material obtained from step (b) from solvent.

18. A copolymer produced according to any of the methods as claimed in claims 1 1, 12, 13, 15, 16 and 17.

19. An article obtained and /or obtainable by a process according to any of claims 11, 13, 15 and 17.

20. An article obtained and/or obtainable by the use of a product as claimed in any of claims 1 to 10 or 13.

21. An article as claimed in claims 19 or 20 is used in the fabrication of a printed circuit board or printing plate.