WO1993022353A1

WO1993022353A1 - Polymers and polymer latices from vinylesters of saturated monocarboxylic acids

Info

Publication number: WO1993022353A1
Application number: PCT/EP1993/001133
Authority: WO
Inventors: Henricus Paulus Hubertus Scholten; Jan Vermeulen; David Pappie; Johannes Jacobus Keijsper; Roger Stewart Downing; Linda Louise Marie Guillaume Coppin; Bernadette Elisabeth Bongenaar-Schlenter; Jan Hofman
Original assignee: Shell Internationale Research Maatschappij B.V.; Shell Canada Limited
Priority date: 1992-05-06
Filing date: 1993-05-04
Publication date: 1993-11-11
Also published as: AU4065893A

Abstract

The invention relates to polymers, obtainable by the polymerization of one or more new vinylesters, and optionally one or more other copolymerizable monomers. The invention also relates to latices containing such polymers; the preparation of such polymers by means of emulsion, solution, or mass polymerization; compositions comprising such latices and to solid polymeric products, for example redispersible latex powders formed by drying of such latices.

Description

- -

POLYMERS AND POLYMER LATICES FROM VINYLESTERS OF SATURATED MONOCARBOXYLIC ACIDS

λ This invention relates to polymers from vinylesters of satu¬ rated monocarboxylic acids, to latices containing such polymers, to the preparation of such polymers by means of emulsion, solution, or mass polymerization, to compositions comprising such latices and to solid polymeric products, for example redispersible latex powders formed by drying of such latices.

Vinylesters are used in many applications, ranging from the surface coating field, adhesives, textile impregnating, paper coating, cement mortars, etc. A group of compounds of particular

10 interest are the vinylesters of α,α-disubstituted (synthetic) monocarboxylic acids of the following formula

•x

wherein R-. , R», and R_ are alkyl groups of which at least one is a methyl group. Especially interesting are vinylesters of a composi¬ tion of acids containing 9 carbon atoms, or of a composition of

15 acids containing 10 carbon atoms (sold by Shell under the trade¬ marks "VeoVa" 9, respectively "VeoVa" 10). Another well-known example is vinyl pivalate (known as "VeoVa" 5). Finally, although no longer available, a vinylester composition is known, previously sold as "VeoVa" 911, comprising a composition of vinylesters of

20 acids containing of from 9 to 11 carbon atoms.

These vinylesters impart on the resulting polymers excellent resistance to both saponification and exposure to ultra-violet light. Accordingly, these vinylester compositions and the polymers prepared therefrom have been subject of many patent applications. .25 Thus, they have been described in respect of emulsion polymers such as in general purpose, high quality and/or highly pigmented emul¬ sion paints, cement mortar modifiers, reactive latex primers; in respect of solution polymers such as solven -borne stoving paints, solven -borne air drying paints, and aqueous stoving paints suit¬ able for application by electrodeposition or spray; and in respect of mass polymers such as outdoor powder coatings, and aqueous or non-aqueous dispersion coatings. Besides many similarities, the vinylesters differentiate in the hardness and flexibility they impart on the polymer. For instance, "VeoVa" 10 is known as a flexibilising comonomer, whereas by contrast "VeoVa" 9 imparts rigidity to the polymer. The second order (glass) transition temperature, Tg, of the homopolymers of these monomers reflect this difference, namely "VeoVa" 10 has a Tg of -3 °C, whereas that of "VeoVa" 9 is 60 ^βC.

Despite the aforementioned excellent properties of the poly- mers of vinylesters of α,α-disubstituted monocarboxylic acid compositions in any of the aforementioned uses, there is still a need for polymers having even better properties, in particular in respect to obtaining enhanced flexibility.

For instance, water-borne coating systems generally contain a volatile organic diluent (coalescing agent) forming part of ^"the polymer particles dispersed in the aqueous phase. It would be desirable for environmental reasons, by proper selection of the monomer starting composition-, if a polymer is found that without use of such organic volatile material is sufficiently flexible to be applied at room temperature or below, leading to a non-tacky coating composition.

A further example of a use of the aforementioned polymers of vinylesters of α.α-disubstituted monocarboxylic acid compositions is in the field of adhesives where a good balance between adhesive- ness, resistance against organic and alkaline/acidic solutions, and flexibility is required. In this field too, co onomers imparting enhanced flexibility are highly desirable.

Also in the other fields mentioned in the introduction, a polymer having an improved flexibility while maintaining the other excellent properties is highly wanted. As a result of extensive research and experimentation, new vinylesters have been developed, the Tg of the homopolymer of which is below -20 ^CC, preferably below -35 ^βC. These vinylesters are in » fact compositions of vinylesters of isomeric saturated, ono-

5 carboxylic acids containing either 11, 12, 13, 14 or 15 carbon * atoms in the acid moiety, which vinylesters have the general formula (I)

wherein R. and R„ each are branched or linear alkyl groups, and R,, based on the weight of the composition of isomeric vinylesters, is

10 hydrogen in 1 to 25 %wt and a branched or linear alkyl group in 75 to 99 %wt, and wherein at least 80 %wt of the alkyl groups are linear alkyl groups.

These vinylester compositions and their process of preparing are claimed and described in European patent application No.

15 92201281. For the sake of clarity and conciseness, these vinylester compositions ("VEC's") will be referred to as VEC 11, VEC 12, VEC 13, VEC 14, and VEC 15 for the compositions containing respectively either 11, 12, 13, 14, or 15 carbon atoms in the acid moiety.

Accordingly, the invention provides for polymers, obtainable

20 by the polymerization of one or more vinylesters, and optionally one or more other copolymerizable monomers preferably in an amount of up to 90 %wt of the total monomer feed, characterized in that the or each vinylester is a composition of vinylesters of isomeric saturated, monocarboxylic acids containing either 11, 12, 13, 14 or

25 15 carbon atoms in the acid moiety, which vinylesters have the general formula (I)

wherein R- and R- each are branched or linear alkyl groups, and R,, based on the weight of the composition of isomeric vinylesters, is hydrogen in 1 to 25 %wt and a branched or linear alkyl group in 75 to 99 %wt, and wherein at least 80 %wt of the alkyl groups are linear alkyl groups, i.e., polymers obtainable by the polymeriza¬ tion of a monomer feed comprising one or more vinylesters selected from VEC 11, VEC 12, VEC 13, VEC 14 or VEC 15, and optionally one or more other copolymerizable monomers preferably in an amount of up to 90 %wt of the total monomer feed.

The polymers of the invention may be prepared by either emulsion, solution or mass polymerization of the monomer feed. The one or more other copolymerizable monomers are suitably selected from monomers such as vinyl chloride, vinyl acetate, vinylidene chloride, vinyl propionate, acrylic acid (ester), methacrylic acid (ester) , alkali or alkaline earth metal vinyl sulphonates, lower olefins (ethene, propene, butene and/or pen- tene) , norbornadiene, other vinylesters, and styrene. Preferably, the one or more other copolymerizable monomers constitute 30 to 90 %wt of the total monomer feed, more preferably 50 to 80 %wt of the total monomer feed.

The optimum composition of the monomer feed used in each of the above polymer preparation processes is easily found by the following procedure. First a set of polymers is prepared from monomer feeds of a formulation similar to a proven monomer formula¬ tion. Then the resulting polymers are tested on their relevant properties (one or more of: storage stability of aqueous polymer suspensions; degree of conversion; hardness; flexibility; methyl- ethyl ketone resistance; water spot resistance; water absorption; etc.) . When schematically setting out the results in as many diagrams (for instance in three-component triangular diagrams) and then superimposing these diagrams, the overlapping area defines the monomer feed that meets the minimum requirements of the determined properties.

Suitable conditions for each of the polymerization methods of preparing the polymers of the invention as well as suitable start¬ ing monomer feeds are more fully disclosed hereinafter. Polymers prepared by emulsion polymerization

Polymer latices which are suitable for use as binders in paints and related products are usually made in batch or continuous (loop) reactors. The presence of surfactant is an essential part of the emulsion polymerization process. Optionally, the polymerization is carried out in the presence of either a protective colloid, which improves the stability and flow-properties of the latex containing the polymer of the invention; a stabilising monomer; or a functional monomer. Polymerization of the monomers occurs by a free-radical propagation reaction.

A polymer as defined above in accordance with the invention is prepared by emulsion polymerization wherein an aqueous emulsion comprising the monomer feed, one or more stabilizers, one or more buffering agents and one or more polymerization initiators is reacted at an elevated temperature.

Suitable monomer feeds resulting in polymers having a superior balance of properties contain one or more of the aforementioned VEC's, and optionally one or more of the monomers selected from: a further vinylester of a carboxylic acid; an alkyl ester of a polymerizable o,-.-ethylenically unsaturated carboxylic acid or their hydroxyethyl- or hydroxypropyl esters; a lower ole in; vinyl chloride; or a stabilising monomer selected from e.g. a,β-et yl- enically unsaturated carboxylic acids, (meth)acrylamide, diaceton acrylamide, sodium vinyl sulphonate, glycidylmethacrylate, or mixtures thereof.

It should be realised that emulsion polymerization of monomer feeds comprising vinylesters is well known, and that in particular the selection of the monomers and the relative amounts thereof is well worked out. For instance in the VeoVa Technical Manual dis- tributed by Shell Resins, part VM 3, reference is made to polymer latices prepared from VeoVa 10. When optimising the monomer feed, the performance requirements for a superior grade polymer for instance comprise a Tg of less than 20 °C, a minimum film-forming temperature (MFT) of from -5 to 20 °C. Moreover, under the reaction conditions exemplified in the examples a monomer conversion of at least 99% is desired. For the purpose of illustration several monomer feeds are disclosed in the examples.

According to one of the preferred embodiment of the present invention, polymers are provided which are derivable from one or more of the aforementioned VEC's and vinyl acetate by emulsion polymerization in the presence of a colloid stabilizer such as hydroxyet yl cellulose (HEC), polyvinylalcohol (PVA) or polyvinyl- pyrrolidone (PVP).

A more preferred embodiment of the polymers of the present invention is formed from the monomer feeds comprising:

(a) from 10 to 80% by weight of VEC 11; and

(b) from 90 to 20% by weight of vinyl acetate (VAc) ; the sum of components (a), and (b) being 100%, and HEC as colloid stabilizer. According to another preferred embodiment of the present invention related to colloid-free latices, polymers are provided which are derivable from the aforementioned VEC's, preferably VEC 11, methyl methacrylate (MMA) , (tert-)butyl (meth)aerylate, and (meth) crylic acid and/or (meth)acrylamide as stabilising monomer. i will be appreciated that due to the above mentioned good monomer conversion based on the solid content, the latices obtained have an attractively low free monomer content, and substantially no unattractive smell or odour.

The polymers containing latices according to the present invention may be prepared under conditions which are known in the art and generally involve a temperature of from 75 to 85 ^βC when thermal initiation is used, or 40 to 70 "C when redox initiation is used.

Stabilizers suitably constitute about 1-8% by weight of the latex in total. It is preferred that the stabilizers used in the latex comprise at least one anionic surface active agent (stability during the polymerization process), or at least one surface active agent of the mixed anionic/non-ionic type (stability of the final latex). Optionally a non-ionic surface active agent is used too. Suitable stabilizers, and the preferred amount to be used in, are for instance disclosed in European patent No. 295,727 and in Emulsifiers and detergents, international edition, volume 1 (by McCutcheon, The Manufacturing Confectioner Publishing Co., Glen Rock NY, USA 1990).

Preferably both an anionic surface active agent such as an alkylaryl sulphonate and a non-ionic surface active agent such as nonylphenol ethoxylate are used.

Suitable initiators, forming free radicals tinder the reaction conditions for the aqueous emulsion polymerization, such as by thermal or chemical breakdown (redox) , may be found in European patent No. 295,727 too. Initiators include organic water soluble peroxides, hydroperoxides, azo compounds and persulphates. Examples are hydrogen peroxide and sodium, ammonium or, especially, potas- sium persulphate. 0.1-1%, preferably 0.4-0.7% of initiator, based on weight of the reaction mixture, is suitably employed.

Suitable buffering agents, to prevent the pH of the mixture falling below about 4 are for instance borax, acetic acid, or an alkali metal carbonate, bicarbonate, or acetate. According to a preferred embodiment of the emulsion polymer¬ ization process of the present invention, a premix is prepared in demineralized water from one or more surface active agents, a stabilising colloid, a part of one or more radical initiators, and a buffer. The reactor is heated to a temperature in the specific range, e.g. 80 ^βC. The reactor charge is heated up. When the temperature reaches 50-60 °C, 10% of the monomer feed is added. ' Polymerization will start and the temperature will rise to 80 °C. The further addition of monomers is started. The addition is normally extended over a period of 2 to 5 hours during which the originally adjusted temperature is maintained. The addition of the remaining amount of initiator in aqueous solution is started at the same time and is continued for a similar period as for the monomer addition.

A post polymerization period after termination of the addition of monomers of 1 to 3 hours is normally used at a temperature of e.g. 80 °C. After this post polymerization, the latex obtained is cooled and if necessary filtered.

The generally obtained latices have a total solids content in the range of from 30 to 60 %wt of the latex and preferably from 40 to 55 %wt and a weight average particle diameter in the range of from either 200-1000 nm (colloid stabilized) or 50-200 nm (colloid- free) depending on the type of surfactants, and when present, the type of colloid.

It will be appreciated that the present invention also relates to coating compositions comprising a latex and preferably at least one pigment. In addition, these paints will commonly contain further constituents, examples being fillers, co-solvents, thicken¬ ers, dispersants, preservatives, fungicides, corrosion inhibitors, and anti-foaming agents. Latices in accordance with the invention may find application as concrete additive, in paper or textile coatings, lacquers, paints, wood coatings, anti-corrosive paints, adhesives, polishes, sealants and textured putties. They are of particular interest for these applications due to their good film forming properties, their water resistance, their high pigment binding power, flexibility, the lack of tackiness of the films, their alkali resistance and resistance to ultra violet light.

A further aspect of the invention is provided by a powder product formed by drying a latex of the invention as defined above. Such a powder could be reconstituted into a latex as required, or incorporated into a product such as a mortar. Polymers prepared by solution polymerization

Polymers in accordance with this embodiment may be applied in water-borne systems, but more commonly are applied in solvent-borne air-drying or thermosetting polymer systems. Besides the applica¬ tions mentioned for the emulsion prepared polymers, solution- prepared polymers find use as adhesive, protective coating or textile coating (air-drying); and heat-cure top-coats for automo¬ tive or general industrial applications, electrodeposition, and coil coatings (thermosetting) . The polymers may be prepared from the same copolymerizable monomers mentioned earlier. Optionally, the monomer feed will include monomers yielding polymers having reactive groups (e.g., ionic polymers), which polymers, optionally together with a curing agent or resin, are suitable used in thermosetting (coating) compositions.

Air-drying solvent-borne polymer compositions may for instance be prepared by copolymerising in a solvent and in the presence of one or more polymerization initiators a monomer feed comprising one or more of the aforementioned VEC's, a further vinylester of a carboxylic acid, and optionally one or more functional monomers.

The further vinylester is suitably vinyl acetate. The optional functional monomers are suitably hydroxyalkyl esters of a polymer- izable α, -ethylenically unsaturated carboxylic acid, in particular hydroxyethyl acrylate and/or hydroxyethyl methacrylate.

The polymerization is generally carried out at a temperature of from 60 to 120 ^βC in a low boiling organic solvent. The initia¬ tor suitably has a half-time at polymerization temperature of 30 to 120 minutes, and may be selected from commercially available initiators such as "Lucidol" B50 (trademark, benzoylperoxide) ,

"Trigonox" 121 (trademark, t-amylperoxy-2-ethylhexanoate) ■, AIBN and the like.

The solvent-borne thermosetting polymer systems may be pre¬ pared by copolymerising in a solvent and in the presence of one or more polymerization initiators a monomer feed comprising one or more of the aforementioned VECs, one or more (hydroxy)alkyl esters of polymerizable o,3-ethylenically unsaturated carboxylic acids, the alkyl group of which contain from 1 to 8 carbon atoms; one or more polymerizable α,?-ethylenically unsaturated carboxylic acids, and optionally styrene. In addition other functional monomers may be applied.

The reaction is suitably carried out at a temperature of 120 to 200 °C in a relatively high boiling solvent. Suitable initiators have a half-time at the polymerization temperature of 120 to 200 minutes, and are for instance available under the trademarks "Trigonox" B (di-t-butylperoxide) and/or C (t-butylperoxybenzoate) .

The selection of the functional monomer depends on the cross- linking agent applied. When the polymer composition is crosslinked with melamine formaldehyde or with (blocked) isocyanates, the functional monomers suitably are hydroxyl-functional monomers; for crosslinking with epoxides, the functional monomers are e.g., acid- functional monomers; and for crosslinking with polyacids glycidyl- functional monomers- are generally applied. For making the polymer water-soluble, suitably an acid or amine-functional monomer is added. Other attractive curing or cross-linking resins for curable coating systems are for example those disclosed in European patent applications Nos. 244,897 and 281,213.

Again, it should be realised that solution polymerization of vinylesters is known by persons skilled in the art, and that in particular the selection of the comonomers, solvent, and initia¬ tors, the relative amounts thereof and the process conditions are well worked out. Reference is for instance made to the VeoVa Technical Manual distributed by Shell Resins, parts VM 4.1 to 4.3, and to the European patent application Nos. 91201546.8 and 91203300.8.

The curable coating compositions according to the present invention can be applied by a variety of methods known in the art, for example by spraying,' dipping or brusb- or roller coating. Pigments, fillers, dispersing agents and other components known for coating formulations may be added to the curable binder system comprising the polymers according to the present invention. Polymers prepared by mass polymerization

A further embodiment of the present invention concerns poly- mers prepared by in situ (co)polymerising one or more of the aforementioned VEC's. These polymers suitably may be used in for instance aqueous or non-aqueous dispersions for application in the coating industry. In addition, they may also be used in solution.

Typically, mass polymerization is carried out in a stainless steel batch reactor equipped with a stirrer, heating and temperature control, a metering pump for addition of the monomer feedstock and a drain valve for dumping the polymer. Since the (co)polymerization rates of the components of the monomer feedstock may be very different, it is often necessary to meter the monomers separately or in a separate rate to obtain random polymers.

Thermosetting mass-polymer systems may be prepared by copoly¬ merising in the presence of one or more polymerization initiators a monomer feed comprising one or more of the aforementioned VEC's, one or more (hydroxy) lkyl esters of polymerizable α, ?-ethylenical- ly unsaturated carboxylic acids, the alkyl group of which contain from 1 to 8 carbon atoms; one or more polymerizable α, -ethylen- ically unsaturated carboxylic acids, and optionally styrene. In addition other functional monomers may be applied.

The in situ reaction is suitably carried out at a temperature of 130 to 200 ^CC. Suitable initiators and functional monomers are mentioned in the preceding part on solution polymerization.

Again, it should be realised that mass polymerization of vinylesters is known by persons skilled in the art, and that in particular the selection of the comonomers, and initiators, the relative amounts thereof and the process conditions are well worked out. Reference is for instance made to the VeoVa Technical Manual distributed by Shell Resins, parts VM 5.1 to 5.3.

The invention will now be further described with reference to the following examples, however without restricting its scope to these specific embodiments.

Example 1, Tg of the homopolymers

The vinylesters listed in Table 1 were heated up to 115 "C in a glass distillation flask of 150 ml. The initiator, dibenzoylper- oxide (dBP) , was added, and after 15 minutes of reaction the reaction vessel was placed into an oven for another two hours of reaction at 90 ^CC. Then, the vinylester homopolymers were dissolved in n-pentane (15 %wt solution) , from which solution the homopoly¬ mers were precipitated by addition of acetone. The glass transition temperature (Tg) of the homopolymers was measured in accordance with the method defined hereinafter. From the reported values (Table 1) it can be concluded that the homo¬ polymers of the VEC's have a low Tg (compare for instance VEC 11 with VeoVa 911, which is also a composition of vinylesters, however not satisfying the requirements as to the degree of substitution and the linearity of the alkyl groups), what will result in a high flexibility. Example 2, 50/50 weight/weight vinyl acetate/vinylester copolymers

In a water bath a reaction vessel was heated up to about 80 °C. To an initial reactor charge comprising 7.5 g of an arylalkyl suphonate anionic surfactant (Humifen SF-90, a trademark, 10 %wt in water); 0.25 g 0.05 borax and 63.25 g

(demineralized) water was added and the vessel was heated for 10 minutes. A pre-emulsion mixture of 148.5 g of the vinylester of Table 1; 148.5 g of vinyl acetate and 3.0 g acetic acid with an aqueous phase comprising 6.0 g of the 10 %wt aqueous anionic surfactant solution; 30.0 g of a non-ionic surfactant (Arkopal N230, a trademark, 25 %wt in water); 1.2 g K_^S-O.; 1.44 g borax and 152.1 g water were pumped into the reactor in 2 hours time. The reaction mixture was allowed to react for another hour while keeping the reaction temperature at 78-80 ^βC.

Both the Tg and the minimum film- orming temperature (MFT) were measured in accordance with the hereinafter described test methods and the results thereof are also listed in Table 1. For the copolymers too- it can be concluded that the application of the vinylesters of general formula (I) result in a low Tg, but also a low MFT. These copolymers were also subjected to a saponificat on test (AR) as defined hereinafter. The results, set out in Table 1, indicate a high alkali resistance for copolymers prepared from the aforementioned VEC's (compare for instance VEC 11 and the vinyl- ester of undecanoic acid) .

Example 3, colloid stabilized copolymers

As set out in Table 2, a series of polymers (a) to (f) were prepared using HEC or PVA as colloid, of which polymers (d) and (e) are comparative examples, and (f) exemplifies a slightly different adhesive-type formulation (*) . The polymers were prepared by heating an initial reactor charge comprising 0.3 parts by weight (pbw) of anionic surfactant;

8 pbw of Antarox CO-850 (25% aq. solution); 0.1 pbw K„S„0_o; 0.5 pbw * *■ L o ^ borax or 0.3 pbw K-CO, ; 2.0 pbw HEC or 2.0 pbw PVA ; 0.2 (0.3 ) pbw glacial acetic acid and 70 (84 ) pbw of water, and 10% of the monomer feed comprising the vinylester of Table 2 and vinyl acetate

(total 10 pbw) to 74 to 77 °C. After about 15 minutes this initial monomer charge has polymerized and the remainder of the monomer

* feed and the initiator solution comprising 0.23 (0.35 ) pbw K-S.O ^• and 12.0 (10.0 ) pbw water were added. The monomer feed is added over a period of 2 to 3 hours. The addition of the initiator solution takes an extra 15 to 20 minutes. After the addition was completed, the reaction mixture was allowed to react for another hour while keeping the reaction temperature at 78-80 °C. The polymer properties were tested i.a. in respect of the hardness (Kόnig hardness, KH) and the results are listed in Table 2. From these results it may be concluded that VEC 11 compares favourably with both VeoVa 10 and the vinylester of 2-ethylhexanoic acid (VEHA). Example 4, colloid-free terpolymers

Similar to the process set out in example 3, three ■ colloid-free terpolymers were prepared using the formulation as listed in Table 3. Example (g) is a conventional formulation, example (h) uses a redox initiator by which a high molecular weight is obtained, and example (j) relates to a formulation wherein the vinyl acetate has been replaced by acrylic acid derivatives. The redox initiator system comprises K_S_0_ and Na„S„0, , and is applied conventionally as exemplified in the VeoVa Technical Manual VM 3.1. Example 5, terpolymer of vinylester, vinyl acetate and ethene A "pressure latex" was prepared in a 1-litre autoclave reactor equipped with a stirrer, thermometer, inlet tubes for initiator, monomers, nitrogen and ethene.

The reactor was charged with 30 g of the anionic surfactant, 0.5 g K-SpOg and 0.25 g borax in 250 g water. A monomer feed was prepared by emulsifying 447.5 g vinyl acetate, 50 g VEC 11, 2.5 g acrylic acid (stabilizer) with 20 g of the anionic surfactant, 40 g of a non-ionic surfactant (a 1/1 mixture of the nonyl phenol ethoxylates "Ethylan" HA and "Ethylan" 44, "Ethylan" is a trade¬ mark) , 2 g IC_jS^Og and 2 g borax in 150 g of water. The initial reactor charge was heated to 80 °C. The monomer pre-emulsion was added to the reactor over a period of 2 hours. Ethene was supplied to the reactor at a pressure of 20 bars until the pre-emulsion addition was complete. After the addition was com¬ plete, the temperature was maintained at 80 °C for a further 2 hours. The polymer was obtained subsequently. Example 6, air-drying solvent-borne copolymer

An initial reactor charge comprising 80 pbw of ethyl acetate (solvent), 8 pbw vinyl acetate, 2 pbw VEC 11 and 0.5 pbw dBP was heated to reflux temperature of 78 ^βC. A monomer feed existing of 72 pbw vinyl acetate and 18 pbw VEC 11 was added over a period of 5i hours. At the same time an additional initiator charge compris¬ ing 1.5 pbw dBP dissolved in- 20 pbw ethyl acetate was added. When the addition was complete, the temperature of the reaction mixture was maintained at a temperature of about 70 °C for a further 2 hours. The polymer was produced in a conversion of 88.7 % with Tg of 25.5 °C and a solids content of 45.8 % m/m. Example 7, thermosetting solvent-borne copolymer

A standard reactor was initially charged with 35.0 pbw VEC 11, 2.2 pbw styrene, 12.0 pbw of "ButylOxitol" (trademark) and 0.2 pbw of t-butylperoxybenzoate (tBPB) . The reactor was heated, and simultaneously at constant rate a mixture consisting of 4.1 pbw acrylic acid (AA) , 6.5 pbw hydroxyethyl methacrylate (HEMA) , 10.8 pbw MMA, 9.0 pbw styrene, 15.0 pbw of ButylOxitol and 0.8 pbw of tBPB was added. In 15 minutes the temperature was raised to about 80 ^βC, and in 1 hour to about 150 to 155 ^βC, the final reaction temperature. This temperature was maintained until the end of addition. After 4*1 hours a mixture of 0.52 pbw AA, 0.71 pbw HEMA, 1.17 pbw MMA, 3.0 p ButylOxitol and 0.2 pbw tBPB was added within h hour. At intervals of approximately hour starting from S hours three further portions of 0.167 pbw of tBPB were added, and the reaction was completed after 6k hours. The polymer was produced in a conversion of 88.9 % with a Tg of 5.1 ^βC and a solids content of 63.9 % m/m.

Two clear laquers were made by blending the aforementioned polymer in a weight ratio of 85/15 or 70/30 with a melamine solution ("Cymel" 301, a trademark) in ButylOxitol (solvent content of 38 % m/m), and catalyst (3 % para-toluenesulphonic acid in ButylOxitol). The laquers were cured at 140 or 160 °C in 30 minutes. The cured laquers showed excellent flow and excellent solvent resistance (more than 100 double rubs with MEK) . The Kδnig hardness varied from 142 to 154 seconds.

Similarly, two pigmented paints were made, employing 70 g of pigment (titane dioxide, "Kronos" 2310, a trademark) per 100 g of the polymer/resin blend (solvent content of 30 % m/m) . The prepared coatings had a Kδnig hardness of from 123 to 144.

Furthermore, a paint for electrodeposition was made by blending the polymer and a melamine solution ("Cymel" 1116, a trademark) in a weight ratio of 70:30, which was subsequently neutralised with triethylamine and diluted with some demineralized water. Pigment was then added to part of this mixture (titane dioxide, 30 % m/m on total polymer), and thouroughly mixed therewith. Then, the remaining part of the polymer/melamine mixture was added, together with sufficient demineralized water to obtain a paint having a solids content of 10%. Paints were applied at different application voltages (ranging from 60 to 160 V) , subsequently followed by a stoving step at 175 ^βC for 30 minutes. The coatings so produced had a glossy appearance. Example 8, thermosetting mass copolymer

A water-dispersible polymer using the mass polymerization technique was prepared by charging a standard reactor with 200 pbw VEC 11 and 150 pbw VeoVa 10 under a nitrogen blanket. The temperature was then raised to 170 ^βC, and a monomer feed comprising 280 pbw styrene, 170 pbw HEMA, 160 pbw butyl acrylate (BuA) , and 20 pbw of tBPB was added at a constant rate over 5 hours whilst maintaining the temperature at 170 °C. After the monomer addition was complete, the temperature was maintained for a further 40 minutes. The polymer was produced in a conversion of 93.2 % with Tg of 4.4 ^βC.

Table 1

Tg (homo) Tg (co) MFT (co) AR (co) Example vinylester ^βC ^βC ^βC mol/mol %

Comparative examples; Ve 13 is the vinylester of a highly branched C._ carboxylic acid and Ve 11 is the vinylester of undecanoic acid.

Example VAc VEC 11 W10

a 90 10 b 80 20 c 70 30 d* 70 30 e* 70 f# 60 40

* Comparative examples; VEHA is vinylester of 2-ethylhexanoic acid,

# example for adhesive application

Table 3

Example VAc VEC 11 W10 W9 MMA AA BuA Part.size Conversion nm %

g 48.5 10 40 1 165 99.7 h 74.5 12.5 12.5 0.5 194 99.1

j 35 55- 1

102 99.5

Test methods

The glass transition temperature (Tg) is measured by means of

Differential Scanning Calorimetry (DSC), by subjecting the polymer under helium atmosphere to a temperature range of -40 to 120 °C at a warming-up speed of 20 ^βC/min. The reported values are so-called second scan figures.

The water absorption of latex polymer and emulsion paint films (Thick film test method) was measured as described hereinafter. A wet film of 2 mm thickness is applied on a polyethylene foil (the latex is kept on the foil by applying an automotive sealer on the edges of the foil). To avoid a too fast evaporation of water and as a result severe mud-cracking the panels are covered with some water vapour transmitting material and then stored at 20 °C above the Tg for a week. The cover is removed after clear films are formed. Three pieces of 2 x 2 cm are cut from the film after removal from the glass panel and weighed to the nearest 0.1 mg. These are stored in demineralized water at 23 °C and reweighed after 14 days (after removal of the excess of water by filter paper). The water absorp¬ tion is calculated from the observed weight increase. The result of the triplicate measurements are averaged.

The water spot resistance of latex polymer films was measured as follows. A wet latex film of 200 micron is applied on a glass panel and allowed to dry for a week at 20 ^βC above the T . When cooled to 23 *C a drop of water is brought on the film and the panel is placed on a dark underground. After 24 hours the whitening effect is visually judged. A rating between 10 (film is unaffected) and 0 (film is completely white) is given. In order to avoid evaporation of the water droplet, it can be covered overnight by a watch glass. The "storage stability" is measured at 40 °C. To obtain an indica¬ tion of polymer suspension storage stability, an accelerated test is carried out at 40 ^βC on a sample of about 100 ml. Viscosity, pH and settlement of solids are noted after various periods of time e.g. 1, 2, 4 and 8 weeks. After 6 weeks the suspension is only allowed to show slight settlement of solids which solids can be easily redispersed, whereas no change in overall viscosity may occur.

The "MEK rubs" is the number of double rubs given by hand to the cured coating with a cloth wetted with methyl ethyl ketone until the coating was wiped off. "MEK rubs" greater than 100 is an indication of a good cure and solvent resistance.

The conversion degree is determined by residual monomer measurement by GLC procedure (cf. VeoVa Technical Manual VM 2.1, pages 24 and 25) which measures residual monomers separately by using standard calibration of the analysis equipment for each monomer to be included in the comonomer starting mixture. The analysis should be carried out shortly after preparation of polymer suspension and before adjustment, if any, of pH.

The hardness of the film is measured as Kόnig hardness (DIN 53157), determined using an Erichson (trademark) apparatus.

The "film thickness" as indicated throughout the present specification was determined with a Permascope ES (trademark) of Fisher.

The viscosity values as indicated throughout the present specification were determined using a B ookfield (trademark) viscosimeter at a temperature of 23 "C (ASTM D445) .

The alkali resistance was determined by the following method. A pre-weighed film, 20X20 mm, prepared by applying a latex with a 200 micron applicator on a PE film after drying 1 week at 20 ^βC above the polymer Tg, was immersed in 2% m/m sodium hydroxide solution for 2 weeks, then rinsed with clean water and dried to constant weight. The weight loss was calculated and reported as a measure of alkali resistance.

The minimum film-forming temperature (MFT) was measured on an heatable panel having a non-porous surface, which panel showed a temperature gradient over the length of the surface varying approx¬ imately 20 ^βC. A latex was applied to the panel to give a 60 micron wet film, and the film was allowed to dry with air flowing over the wet film. The MFT was assessed visually as the temperature below which the film begins to crack, indicating incomplete coalescence of the film.

Film flexibility is either determined by a conical mandrel test (ASTM D 522) or by an impact resistance test (ASTM D2974-84) .

Claims

C L A I M S

1. Polymers, obtainable by the polymerization of one or more vinylesters, and optionally one or more other copolymerizable monomers preferably in an amount of up to 90 %wt of the total monomer feed, characterized in that the or each vinylester is an composition of vinylesters of isomeric saturated, monocarboxylic acids containing either 11, 12, 13, 14 or 15 carbon atoms in the acid moiety, which vinylesters have the general formula (I)

wherein R. and R_ each are branched or linear alkyl groups, and R_, based on the weight of the composition of isomeric vinylesters, is hydrogen in 1 to 25 %wt and a branched or linear alkyl group in 75 to 99 %wt, and wherein at least 80 %wt of the alkyl groups are linear alkyl groups.

2. Polymers as claimed in claim 1, obtainable by emulsion poly¬ merization, wherein an aqueous emulsion comprising the monomer feed, one or more stabilizers, one or more buffering agents and one or more polymerization initiators is reacted at an elevated temper¬ ature.

3. Polymers as claimed in claim 2, wherein the monomer feed further comprises anyone or more of the monomers selected from: a further vinylester of a carboxylic acid; an alkyl ester of a polymerizable α, --ethylenically unsaturated carboxylic acid; a lower olefin; vinyl chloride; or a stabilising monomer selected from e.g. α, -ethylenically unsaturated carboxylic acids or their hydroxyethyl- or hydroxypropyl esters, (meth)aerylamide, diaceton aerylamide, sodium vinyl sulphonate, glycidylmethacrylate, or mixtures thereof.

4. Polymers as claimed in claim 2, wherein the monomer feed further comprises vinyl acetate.

5. Polymers as claimed in claim 1, obtainable by solution poly¬ merization, wherein an organic solution comprising the monomer feed, an organic solvent, optionally one or more chain transfer agents and one or more polymerization initiators is reacted at an elevated temperature.

6. Polymers as claimed in claim 1, obtainable by mass polymeriza¬ tion, wherein the monomer feed, optionally one or more chain transfer agents and one or more polymerization initiators is reacted at an elevated temperature.

7. Polymers as claimed in claim 5 or 6, wherein the monomer feed further comprises one or more (hydroxy)allqrl esters of polymer¬ izable α,?-ethylenically imsaturated carboxylic acids, the alkyl group of which contain from 1 to 8 carbon atoms; one or more polymerizable α, J-ethylenically imsaturated carboxylic acids, and optionally styrene.

8. A latex containing as polymeric constituent 30 to 60 % by weight of an polymer according to claim 1.

9. Coating compositions comprising a latex according to claim 8.

10. A solid polymeric product by physical drying of the latex according to claim 8.