ITMI970669A1 - CYCLOALIFATIC EPOXY RESINS - Google Patents

Description

DESCRIPTION

The present invention relates to novel solid cycloal epoxy resins with improved properties and their use in thermosetting powder coatings.

Cycloaliphatic epoxy resins are used in important fields such as electrical / electronic equipment and applications, in filament winding technology and coatings.

In coating applications, cycloal fat epoxy resins are mainly used in coatings for high performance open air applications, thanks to their very high resistance to atmospheric agents and ultraviolet radiation.

The powder coating is becoming progressively more widespread as it avoids the use of solvents and the pollution problems associated with them. In thermosetting powder coatings, epoxy resins are used as crosslinking agents in combination with carboxylic terminated polyester resins. The most widely used epoxy cross-linking agent is triglycidylisocyanurate (TGIC; compare, for example, EP-A-0 107 888). This compound, which is a solid with a softening point in the range of 90 to 100 ° C, has good technical properties but gives rise to toxicological problems. Furthermore, it is a suspected mutagenic agent (positive AMES test).

On the other hand, existing cycloaliphatic epoxy resins such as the well known 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate which is a low viscosity liquid are not suitable for this application.

US-A-5 244 985 owned by New Japan Chemical describes the preparation of a family of epoxidized polyesters containing epoxy groups of ohexane with a molecular weight between 1000 and 10000. The products described in the examples are liquid. For this reason they are suitable for use with liquid carboxylic anhydrides, for UV hardening, or as plasticizers for PVC. They are not suitable, however, for powder coating applications.

Therefore, an object of the present invention is to provide substitutes for T6IC which are free from toxicity problems and which have physico-chemical characteristics and performance suitable for thermosetting powder coatings or which can be incorporated into stable powder compositions. which have no tendency to agglomerate.

This object has been achieved by means of the solid epoxidized polyester resin according to claim 1 and by means of the process for its production according to claims 7 and 8.

It has been found that by using an appropriate manufacturing process it is possible to prepare a family of epoxidized polyesters which are solid and suitable for thermosetting powder coating applications.

These solid epoxidized polyester resins comprise at least one epoxidized ester which contains, per molecule, two or more cycloal fatal carboxy groups of the general formula:

in which

R * e are independently selected from the group consisting of hydrogen and methyl or R ^ and R ^ together are methylene.

R ^ and R * are independently selected from the group consisting of hydrogen and methyl. The dicarboxylic cycloaliphatic groups are linked by their open valences to groups independently selected from hydrogen, linear or branched C ^ g alkyls, C2-g alkanediyl linear or branched ligands, C3-8 alkathyls linear or branched ligands (crosslinkers), C4- alkantetrayls 8 linear or branched ligands (crosslinkers), and ligands or crosslinkers of general formula X (Y-) n where n is an integer from 2 to 4, X and a di-, tri- or tetravalent group, containing at least one isocyclic ring or heterocyclic and Y is a direct bond or group - (CH2) m-in which m is an integer from 1 to 4. Here and in the following, the term "open valence" means any valence of a group that is (formally) available to engage in a bond with another group. In the molecule as a whole, there are of course no open valences. When the epoxidized ester contains at least two cycloaliphatic groups, they comprise "terminal" carboxylate functions which are bonded to Cj-8 alkyl hydrogen, forming a Cj-g alkyl ester or a free carboxylic acid function, respectively, and "internal" carboxylate functions which are linked or cross-linked by the aforementioned diyls, trills, tetrayls or di-, tri- or tetravalent groups. In this context, linear or branched C ^ _g alkyl means any alkyl group having up to eight carbon atoms and any possible number of branches, for example, ethyl, methyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl , pentyl, 3-methylbutyl (isoamyl), tert-pentyl, neopentyl, slender, octyl, 2-ethylhexyl. According to linear or branched C2-g alkandyls means any alkanediyl group having from 2 to 8 carbon atoms and any number of branches, except those having two open valences on the same carbon atom, for example 1,2-ethanediyl, 1,2 -propanediyl, 1,3-propanediyl, 1,2-butanediyl, 1,3-butanediyl, 1,3-butanediyl, 1,4-butanediyl, 2,3-butanediyl, 2-methyl-1,3-propanediyl, 3 -methyl-1,3-butanediyl, 1,2-hexanediyl, 1,6-hexanediyl or 2,2-dimeth1-1,3-propanediyl. Accordingly, linear or branched C3-g alkantryl means any alkantriyl group having from 3 to 8 carbon atoms and any number of branches, except those having two or three open valences on the same carbon atom, e.g. 1,2,3- propantriyl, or 2,2-dimethylbutan-1, r, 1 "-triyl. Accordingly, linear or branched C4-g alkantetrayl means any alkantetrayl group having 4 to 8 carbon atoms and any number of branches, except those having 2 or 3 open valences on the same carbon atom, for example 1,2,3,4-butantetrayl and 2,2-dimethylpropan-1, r, I ", 3-tetrayl. The term" di-, tri- or tetravalent groups containing at least one isocyclic or heterocyclic ring "means any organic group having from two to four valences and containing any number of isocielic or heterocyclic rings, for example triaz1n1c1 rings. According to the invention, epoxy polyester resins are essentially free from monomeric products. prod the monomers are to be understood as compounds containing only a cycloaliphatic group of the type defined above, particularly those in which both open valences are linked to hydrogen or Cj-8 alkyl and any significant residual quantity of hydroxy-11c1 compounds from the synthesis of the polyester resin. "Essentially free of monomer products" is to be understood as containing less than 5% by weight, preferably less than 3% by weight, of such products.

Preferably one of the substituents R <1> to R <4> is hydrogen or a methyl group and the remaining ones of R <1> to R <4> are hydrogens. The compounds according to this embodiment are derived from tetrahydrophthalic and methyltetrahydrophthalic acids.

Also preferred are resins wherein R <1> and R <4> together are methylene, one of and R <3> is hydrogen or methyl and the other is hydrogen. These compounds are derived from nadic acid (= bicyclo [2.2.2] hept-5-ene-2,3-dicarbox1H-co) and methylnadic acid.

The C1 alkyls are preferably selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl and 2-ethyl. More preferably, Isobutyl is used as the Cj_g alkyl. The C2_g alkanediyl ligands, if present, are preferably selected from 1,2-ethanediyl, 1,2-propanedyl, 1,3-propanediyl, 1,2-butanediyl, 1,3-butanediyl, 1,4-butanediyl, 2, 3-butanediyl, 3-methyl-1,3-butanediyl, 1,2-hexane, 1,6-hexane and 2,2-dimethyl-1,3-propanediyl. The alkantryl Cg_g ligands (crosslinkers), if present, are preferably - selected from 1,2,3-propantry and 2,2-dimethyl butane-Ι, Γ, Γ-tri le. The alkantetrayl c4-8 binders (crosslinkers) if present, are preferably selected from 1,2,3,4-butantetrayl and 2,2-dimeth 1 propane -1, 1 <1> - 1 ", 3- tetrai 1 e.

As ligating or crosslinking groups of general formula X (Y-) n, if present, isocyanurate groups of formula

Preferably, the solid epoxidized polyester resin according to the invention has an acid number not higher than 2 mg KOH / g, more preferably, not higher than 1 mg KOH / g. This means that essentially no free carboxyl groups are present.

The molecular weight (weight average) as determined by gel permeation chromatography is typically between about 500 and 10,000, preferably between 1000 and 5000.

According to the invention, solid epoxidized polyester resins can be prepared by

1) reaction of an unsaturated dicarboxylic acid or derivative of the general formula

where a are as defined above and Q * and Q <2> are Independently 1 O selected from the group consisting of hydroxy and C ^ g alkoxy or Q <1> and <(> r together are -0-, with at least one Hydroxyl compound selected from the group consisting of linear or branched C2_g alkandyls, linear or branched C3_g alcohols, linear or branched C ^ _g alkantetraols and hydroxyl compounds of general formula X (Y-OH) n where n is an integer from Z to 4 , X is a di-, tri- or tetravalent group containing at least one heterocyclic isocyclic ring and each Y is a direct bond or a - (CH2) m- group in which m is an integer from 1 to 4;

and a linear or branched Cj_g alkanol,

ii) removal of essentially all monomeric by-products, and ii) epoxidation of the resulting unsaturated resin.

In this process the unsaturated dicarboxylic acids can be used as such (Q <1 => Q <z> = OH) or in the form of their di-C ^ g-alkyl esters (Q <1> = Q <2> = C1 -8alkyl) or anhydrides (Q <1> + Q <2> = -0-). Accordingly, the first stage is a direct esterification if an anhydride and an acid are used and a transesterification if a dialkyl ester is used as starting material. In the first case, the linear or branched C ^ _g alkanol is required to esterify the "terminal" carboxyl functions of the resulting polyester.

Another process for preparing the epoxidized polyester resins according to the invention comprises the steps of:

i) reacting an unsaturated dicarboxylic acid or derivative of general formula

wherein R <1> to R <4> are as defined in claim 1 and Q <1> and Q <z> are Cj_g alkoxy groups, with at least one hydroxyl compound selected from the group consisting of linear or branched C2_g alkanies, alkantriollei Linear or branched C3_g, linear or branched C ^ _g alkantetraols and hydroxyl compounds of general formula X (Y-0H) n, where n is an integer from 2 to 4, X is a di-, tri- or tetravalent group containing at least an isocielic or heterocyclic ring and each Y is a direct bond or group - (CH2) m in which m is an integer from 1 to 4,

ii) essentially removing all monomeric by-products, e

iii) epoxidizing the resulting unsaturated polyester by reacting it with a peroxide compound.

In this case the dialkyl esters are used as starting materials and therefore only transesterfraction reactions are required in the first stage. In the resulting polyester, the "terminal" carboxyl functions still carry the alkyl groups which were present in the starting alkyl ester.

Depending on the type of alkyl C ^ _a alkyl groups or the di-, tri- or tetravalent ligand (cross-linking) groups to be introduced, suitable hydroxyl compound starting materials are used.

The preferred groups, methyl, ethyl, propyl, isopropyl, butyl, isobutyl and 2-ethylheyl are introduced using methanol, ethanol, propanol, isopropyl alcohol, butanol, isobutyl alcohol (particularly preferred) and 2-ethylhexanol, respectively. The preferred groups, 1,2-ethanediyl, 1,2-propanediyl, 1,3-propanedyl, 1,2-butanediyl, 1,3-butanediyl, 1,4-butanediyl, 2,3-butanediyl, 3-methyl- 1,3-butanediyl, 1,2-hexandiyl, 1,6-hexandiyl and 2,2-dimethyl-1,3-propanediyl. They are introduced using ethylene glycol, propylene glycol, 1-3 propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl -1,3-butanediol or, 1,2-hexanediol and 2,2-dimethyl 1 -1,3-propanediol (neopentylgl 1cole), respectively. Preferred groups 1,2,3-propantriyl and 2,2-dimethylbutane-1,1 ', 1 "-triyl are introduced using glycerol and trimethylolopropane, respectively. Preferred groups 1,2,3,4-butantetrayl and 2,2-dimethylpropane-1,1,1,3-tetrayl are introduced using threitol / erythritol and pentaeri tritol, respectively.

Favorite groups of formula:

are introduced using tris (2-hydroxylethyl) isoc1anurate as the hydroxyl compound.

In the second stage of the preparation of the epoxidized polyester resin, the molecular mass distribution of the crude polyester is modified by eliminating the molecules with lower molecular mass, for example the monomeric dialkyl esters.

Preferably, the lower molecular mass molecules are removed by distillation. This distillation is advantageously carried out under vacuum. After distillation, the residue has a relatively narrow molecular mass distribution. Other possible methods for removing the low molecular mass products are, for example, liquid chromatography or membrane separation processes, such as ultrafiltration.

In the third step, the unsaturated ester precursor with a narrow molecular weight distribution is epoxidized by reaction with a peroxide compound.

Both organic and inorganic peroxide compounds can be used as the peroxidic compound. Preferably, peroxycarboxylic acidic peroxidic compounds such as peracetic acid or m-chloroperbenzoic acid are used. Monoperphthalic acid is particularly preferred.

Hydrogen peroxide is also a preferred peroxide compound. A phase transfer catalyst may be used when using hydrogen peroxide. Examples of suitable phase transfer catalysts are described in J. Polym. Sci., Part A: Polym. Chem.

1993,31, 1825-1838.

The epoxidation reaction is advantageously carried out in an inert solvent. Suitable inert solvents are, for example, alkylalkanoates, halogenated hydrocarbons, cycloaliphatic hydrocarbons, aromatic hydrocarbons or alcohols.

In powder coating, the powder for coating usually comprises a thermosetting binder composition and further ingredients such as catalysts, pigments, mineral fillers and auxiliary materials. The thermosetting binder composition may be a one component binder composition which can be used as such or a two component binder composition which comprises a hardener and a reactive polymer. The terms "one component" and "two components" in this context are independent of the actual chemical composition, i.e. a one-component bonding composition may contain several compounds. Furthermore, each component of a two-component binder composition may contain several compounds.

Preferred compositions which are suitable both for one-component binding compositions and, as a hardening component, for two-component binding compositions, comprise at least one solid epoxidized polyester resin according to the invention and, optionally, a catalyst. Suitable catalysts for this type of composition are, for example, Lewis acids such as complexes of boron trifluoride or Lewis bases as tertiary amines.

According to a particularly preferred embodiment of the invention, the solid epoxidized polyester compounds according to the invention are used in compositions which also comprise at least one polymer capable of reacting with epoxy groups.

As polymers capable of reacting with epoxy groups, polymers containing carboxy groups, polymers containing anhydride groups, polymers containing hydroxy groups, polymers containing amino and / or amido groups or (other) polymers containing epoxy groups are preferably used. Particularly preferred as polymers capable of reacting with epoxy groups are polymers based on polyesters, polyacrylates or polyethers which are modified so as to contain the functional groups mentioned above. Depending on the type of functional groups present in the reactive polymers, suitable catalysts known in the art can be used to accelerate the crosslinking process.

Particularly preferred as polymers capable of reacting with epoxy groups are carboxylated polyesters with an acid number from 10 to 70 mg KOH / g of resin and a glass transition temperature Tg from 50 to 70 ° C. Resins of this type are available from Vianova Resins, a company of the Hoechst group, under the brand name Alftalat®.

The compositions comprising at least one solid epoxidized polyester resin according to the invention and at least one polymer capable of reacting with epoxy groups can be blends with no substantial degree of polymerization between the epoxidized polyester resin and the other polymer. These blends are often called master blends.

According to another way of operating, the compositions are prepo-cured, i.e. crosslinking has taken place to some extent, but without significantly damaging the thermosetting properties of the composition. These compositions are often called prepolymer compositions.

The masterbatch compositions can be prepared by melting - separately or together - the solid epoxy polyester resin and the polymer capable of reacting with the epoxy groups, mixing the melts completely, solidifying and comminuting the composition. Especially the mixing should be carried out at a temperature at which no substantial crosslinking takes place.

The prepolymer compositions can be prepared by melting - separately or together - the solid epoxy polyester resin and the polymer capable of reacting with the epoxy groups, mixing the melts thoroughly, maintaining the mixture at a temperature where crosslinking is possible for a sufficient time. to obtain the desired degree of crosslinking, by solidifying the mixture and chopping it.

Both the epoxidized solid polyester resin as such and the compositions described above can be used in one-component thermosetting binder compositions suitable for powder coatings. When used as such, ie without the addition of polymers capable of reacting with epoxy groups, the solid epoxidized polyester resins according to the invention give homopolymerized epoxy resins by crosslinking.

Further, both the epoxidized solid polyester resins as such and the compositions described above can be used as curing components in two-component thermosetting binder compositions suitable for powder coating which comprise a curing component, a reactive polymer component comprising at least one reactive polymer capable of react with epoxy groups and possibly a catalyst. If the masterbatch or prepolymer compositions are used as the hardener component, the reactive polymer in the second component can be the same as that contained in the hardener or different.

In the two-component binding compositions, as polymers capable of reacting with epoxy groups, polymers containing carboxy groups, polymers containing anhydride groups, polymers containing hydroxy groups, polymers containing amino and / or amido groups or (other) polymers containing amino groups are preferably used epoxies.

Particularly preferred as polymers capable of reacting with epoxy groups are polymers based on polyesters, polyacrylates or polyethers which are modified so as to contain the functional groups mentioned above.

Particularly preferred as polymers capable of reacting with epoxy groups are carboxylated polyesters with an acid number from 10 to 70 mg KOH / g of resin and a glass transition temperature Tg from 50 to 70 ° C. Resins of this type are available from Vianova Resins, a company of the Hoechst group, under the Alftaìai® brand.

Particularly suitable for powder coating are powder coating compositions containing one or two component binding compositions as described above and one or more substance (s) such as pigments, catalysts, crosslinking agents, including polymers capable of reacting with epoxy groups, mineral fillers and auxiliary materials. Auxiliary materials include materials such as flow aids, antioxidants, etc.

The powder coating compositions can be prepared by methods known in the art, for example by mixing and extruding the components in a heated extruder and subsequently comminuting the solid extrudate to a particle size suitable for the usual coating techniques.

The coating process can be carried out by applying the powder coating compositions on a substrate, for example by electrostatic spraying or other known method, by hardening the coating by subjecting it to heat for a sufficient time at a suitable temperature to obtain a fully cured coating.

The invention will be further described on the basis of the following non-limiting examples. Molecular masses were determined by gel permeation chromatography (GPC). The relative areas of the peaks refer to the resolved peaks (at high retention times) only, while the average molecular masses were determined from the complete elution plots.

Comparative example A

Preparation of a polyester from 1,2,3,6-tetrahydrophthalic acid, ethylene glycol and isobutyl alcohol without distillation of the low boiling fraction.

One flask was loaded with 456.3 g (3 mol) of 1,2,3,6-tetrahydrophthalic anhydride (THPA), 124.1 g (2 mol) of ethylene glycol, 148.2 g (2 mol) of 1sobut1l1co alcohol and 20 g of xylene. The mixture was heated and the temperature was gradually raised to 230 ° C. The esterification reaction was carried out by distilling off the water formed until the acid number of the mixture was 15 mg KOH / g. At that point 0.5 g of stannous oxide was added. After about 12 hours, the xylene was distilled at 230 ° C under vacuum, from 1000 to 136 mbar. The reaction mixture was filtered and 675 g of polyester was obtained.

Iodine number: 110 (calculated: 113)

Comparative example B

Epoxidation of the polyester obtained in comparative example A

The crude polyester of 1,2,3,6-tetrahydrophthalic acid, ethylene glycol and isobutyl alcohol, obtained in comparative example A (225 g, 1 eq) was dissolved in 450 g of ethyl acetate at 50 ° C. Solid monoperphthalic acid (purity 95%, 249 g, 1.3 moles) was added in portions over an hour. By immersing the reaction flask in cold water, the temperature of the stirred reaction mixture was kept at 50 ° C. When the exothermic reaction ceased, the flask was immersed in a hot bath and the reaction mixture was kept at 50 ° C for a further two hours. After cooling to room temperature, the reaction mixture was filtered and the liquid washed with aqueous sodium carbonate and then with water. The organic layer was concentrated in vacuo and dried at 80 ° C / 13 mbar to give 245 g of epoxy resin.

Oxirane content: 5.9% by weight

1100 (10%)

Example 1

Polyester of 1,2,3,6-tetrahydrophthalic, glycoethylene and isobutyl alcohol

One flask was loaded with 456.3 g (3 mol) of 1,2,3,6-tetrahydrophthalic anhydride (THPA), 124.1 g (2 mol) of ethylene glycol, 148.2 g (2 mol) of isobutyl alcohol and 20 g of xylene. The mixture was heated and the temperature was gradually raised to 230 ° C. The esterification reaction was carried out by distilling off the water formed until the acid number of the mixture was 15 mg KOH / g. 0.5 g of stannous oxide was then added. After about 12 hours the xylene and 110 g of diisobutyltetrahydrophthalate were distilled off under vacuum at 230 ° C, gradually reducing the pressure from 1000 to 13 mbar. The reaction mixture was filtered and 565 g of polyester were obtained.

Iodine number: 114 (calculated: 113)

Example 2

Epoxidation of the polyester obtained in Example 1

The raw polyester of 1,2,3,6-tetrahydrophthalic acid, ethylene glycol and isobutyl alcohol obtained in Example 1 (224 g, 1 eq) was dissolved in 450 g of ethyl acetate at 50 ° C. Solid monoperphthalic acid (purity 95%, 249 g, 1.3 mol) was added portionwise over an hour. By immersing the reaction flask in cold water, the temperature of the stirred reaction mixture was maintained at 50 ° C. When the exothermic reaction ceased, the flask was immersed in a hot bath and the reaction mixture was kept at 50 ° C for a further two hours. After cooling to room temperature, the reaction mixture was filtered and the liquid washed with aqueous sodium carbonate and then with water. The organic layer was concentrated in vacuo and dried at 80 ° C / 13 mbar to give 240 g of solid epoxy resin with a softening point of about 60 ° C.

Comparative example C

Preparation of a polyester of 1,2,3,6-tetradyrophthalic acid, neopentyl glycol and isobutyl alcohol without distillation of the low boiling fraction.

One flask was loaded with 456.3 g (3 mol) of 1,2,3,6-tetraldorphthalic anhydride (THPA), 208,3 g (2 mol) of neopentyl glycol, 148,2 g (2 mol) of isobutyl alcohol and 20 g of xylene. The mixture was heated and the temperature was gradually raised to 230 ° C. The esterification reaction was carried out by distilling off the water formed until the acid number of the mixture was 15 mg KOH / g. Then 0.5 g of stannous oxide was added. After about 12 hours, the xylene was distilled off at 230 ° C under vacuum, from 1000 to 136 mbar. The reaction mixture was filtered and 760 g of polyester were obtained.

Comparative example D

Epoxidation of the polyester obtained in comparative example C

The raw polyester of 1,2,3,6-tetrahydrophthalic acid, neopentylglycol and isobutyl, obtained in Comparative Example C (258 g, 1 eq) was dissolved in 500 g of ethyl acetate at 50 <D> C. Monoperphthalic acid (95%, 249 g, 1.3 moles) was added portionwise over an hour. By immersing the reaction flask in cold water the temperature of the stirred reaction mixture was maintained at 50 ° C. When the isothermal reaction ceased, the flask was immersed in a hot bath and the reaction mixture was kept at 50 °. C for another two hours. After cooling to room temperature the reaction mixture was filtered and the liquid washed with aqueous sodium carbonate and then with water. The organic layer was concentrated in vacuo and dried at 80 ° C / 13 mbar to give 271 g of epoxy resin.

Example 3

Polyester of 1,2,3,6-tetrahydrophthalic acid, neopentyl glycol and isobutyl alcohol.

One flask was loaded with 456.3 g (3 mol) of 1,2,3,6-tetrahydrophthalic anhydride (THPA), 208.3 g (2 mol) of neopentyl glycol, 148.2 g (2 mol) of isobutyl alcohol and 20 g of xylene. The mixture was heated and the temperature was gradually raised to 230 ° C. The esterification reaction was carried out by distilling away the water formed until the acid number of the mixture was 15 mg KOH / g. 0.5 g of stannous oxide was then added. After about 12 hours, the xylene and 160 g of diisobutyl tetrahydrophthalate were distilled off under vacuum at 230 ° C, gradually reducing the pressure from 1000 to 13 mbar. The reaction mixture was filtered and 760 g of polyester were obtained.

Iodine number: 100 (calculated: 100)

Example 4

Epoxidation of the polyester obtained in Example 3

The raw polyester of 1,2,3,6-tetrahydrophthalic acid, neopentyl glycol and isobutyl alcohol obtained in Example 3 (253 g, 1 eq) was dissolved in 500 g of ethyl acetate at 50 ° C. Solid monoperphthalic acid (purity 95%, 249 g, 1.3 moles) was added in portions over an hour. By immersing the reaction flask in cold water the temperature of the stirred reaction mixture was maintained at 50 ° C. When the exothermic reaction ceased, the flask was immersed in a hot bath and the reaction mixture was kept at 50 °. C for another two hours. After cooling to room temperature, the reaction mixture was filtered and the liquid washed with aqueous sodium carbonate and then with water. The organic layer was concentrated in vacuo and dried at 80 ° C / 13 mbar to give 266 g of epoxy resin.

Oxirane content: 5.3% by weight

Example 5

Polyester of 1,2,3,6-tetrahydrophthalic acid trimethylolpropane and isobutyl alcohol

One flask was loaded with 1369 g (9 moles) of 1,2,3,6-tetrahydrophthalic anhydride (THPA), 404.5 g (3 moles) of trimethylolpropane (= 2-ethyl-2- (1droxymethyl) -l , 3-propanediol), 699 g (9.4 moles) of isobutyl alcohol and 35 g of xylene. The mixture was heated and the temperature was gradually raised to 230 ° C. The esterification reaction was carried out by distilling away the water formed until the acid number of the mixture was 18 mg KOH / g. Then 1.2 g of stannous oxide was added. After about 24 hours, the xylene and 589 g of diisobutyl tetrahydrophthalate were distilled off under vacuum at 230 ° C, gradually reducing the pressure from 1000 to 13 mbar. The reaction mixture was filtered and 1677 g of polyester were obtained.

Pol yester of 1,2,3,6-tetrahydrophthalic acid trimethylol propane and alcohol 1 ico osbuti

One flask was loaded with 1056 g (7 mol) of 1,2,3,6-tetrahydrophthalic anhydride (THPA), 582 g (2 mol) d1 dlisobutyl tetrahydrophthalate, 404.5 g (3 mol) of trimethylolpropane, 388 g ( 5.2 moles) of isobutyl alcohol and 40 g of xylene. The mixture was heated and the temperature was gradually raised to 230 ° C. The esterification reaction was carried out by distilling away the water formed until the acid number of the mixture was 18 mg KOH / g. Then 1.3 g of stannous oxide was added. After about 24 hours, the xylene and 695 g of diisobutyl tetrahydrophthalate were distilled off under vacuum at 230 ° C, gradually reducing the pressure from 1000 to 13 mbar. The reaction mixture was filtered and 1501 g of polyester were obtained.

Number of iodine: 102.3 (calculated: 102.5)

Acid number: 1 mg KOH / g

Viscosity at 100 ° C: 71300 mPa.s

M *: 2600

Example 7

Epoxidation of the polyester obtained in example 6

The raw polyester of 1,2,3,6-tetrahydrophthalic acid, trimethylolpropane and Isobutyl alcohol obtained in Example 6 (100 g, 0.4 eq) was dissolved 1n 255 g of xylene with 1 g of methyltriotti1ammonium chloride at 40 ° C. 115 g of an aqueous solution containing hydrogen peroxide (0.54 mol), sodium tungstate (0.02 mol) and phosphoric acid (0.06 mol) was quickly added to this mixture. By immersing the reaction flask in cold water the temperature of the stirred reaction mixture was maintained at 40 ° C. When the exothermic reaction ceased, the flask was immersed in a hot bath and the reaction mixture was kept at 40 °. C for 4 hours. After cooling, the organic layer was concentrated under vacuum to give 110 g of solid epoxy resin with a softening point of about 80 ° C.

Oxirane content: 4.8% by weight

Iodine number: 2.5

Acid d1 number: 0

Viscosity a

100 ° C: 13400 mPa.s

2700

Example 8

Epoxidation of the polyester obtained in example 6

The crude polyester of 1,2,3,6-tetrahydrophthalic acid trimethylolpropane and isobutyl alcohol obtained in Example 6 (100 g, 0.4 eq) was dissolved in 200 g of ethyl acetate at 50 ° C. Solid monoperphthalic acid (purity 95%, 100 g, 0.52 mol) was added portionwise over an hour. By immersing the reaction flask in cold water the temperature of the stirred reaction mixture was maintained at 50 ° C. When the isothermal reaction ceased, the flask was immersed in a hot bath and the reaction mixture was kept at 50 °. C for another two hours. After cooling to room temperature, the reaction mixture was filtered and the liquid washed with aqueous sodium carbonate and then poured with water. The organic layer was concentrated in vacuo and dried at 80 ° C / 13 mbar to give 103.3 g of solid epoxy resin with a softening point of about 80 ° C.

Oxirane content: 5.1% by weight

Iodine number: 1

Acid number: 0

Viscosity at 100 ° C: 39500 mPa.s

F ^: 2700

Example 9

Pol yester of 1,2,3,6-tetrahydrophthalic acid pentaeri tritol and isobutyl alcohol

One flask was loaded with 1217 g (8 moles) of 1,2,3,6-tetrahydrophthalic anhydride (THPA), 273 g (2 moles) of pentaerythritol (= 2,2-bis (hydroxymethl1) -1,3- propanediol), 594 g (8 moles) of isobutyl alcohol and 37 g of xylene. The mixture was heated and the temperature was gradually raised to 230 ° C. The esterification reaction was carried out by distilling away the water formed until the acid number of the mixture was 22 mg KOH / g. 1.5 g of stannous oxide was then added. After about 24 hours, the xylene and 540 g of diisobutyltetrahydrophthalate were distilled off under vacuum at 230 ° C gradually reducing the pressure from 1000 to 13 mbar. The reaction mixture was filtered and they are

3⁄4: 2300

Example 10

Epoxidation of the polyester obtained in example 9

The crude polyester of 1,2,3,6-tetrahydrophthalic acid, pentaerythritol and isobutyl alcohol obtained in Example 9 (149 g, 0.6 eq) was dissolved in 300 g of ethyl acetate at 50 ° C.

Solid monoperphthalic acid (purity 95%, 150 g, 0.78 moles) was added in portions during one hour. By immersing the reaction flask in cold water the temperature of the stirred reaction mixture was kept at 50 ° C. When the isothermal reaction ceased, the flask was immersed in a hot bath and the reaction mixture was kept at 50 ° C for a further two hours. After cooling to room temperature, the reaction mixture was filtered and the liquid washed with aqueous sodium carbonate and then with water. The organic layer was concentrated in vacuo and dried at 80 ° C / 13 mbar to give 160 g of solid epoxy resin.

Oxirane content: 5.8% by weight

Iodine number: 0.9

Acid number: 0

Melting temperature: 1Z3 ° C

3⁄4: 2900

Example 11

Polyester of 1,2,3,6-tetrahydrophthalic acid, tris (hydroxy ethyl) isocyanurate and isobutyl alcohol

One flask was loaded with 913 g (6 moles) of 1,2,3,6-tetrahydrophthalic anhydride (THPA), 523 g (2 moles) of tris (hydroxyethyl) 1socyanurate, 445 g (6 moles) of isobutyl alcohol and 50 g of xylene. The mixture was heated and the temperature was gradually raised to 230 ° C. The esterification reaction was carried out by distilling away the water formed until the acid number of the mixture was 21 mg KOH / g. Then 1 g of stannous oxide was added. After about 15 hours, the xylene and 435 g of diisobutyl tetrahydrophthalate were distilled off under vacuum at 230 ° C, gradually reducing the pressure from 1000 to 13 mbar. The reaction mixture was filtered and 1340 g of polyester were obtained.

Iodine number: 83 (calculated: 86)

Acid number: 0.53 mg KOH / g

Viscosity at 100 <D> C: 26350 mPa.s

1400

Color: 8 Gardner

Example 12

Epoxidation of the polyester obtained in example 11

The raw polyester of 1,2,3,6-tetrahydrophthalic acid tris (hydroxyethylisocyanurate and isobutyl alcohol obtained in Example 11 (306 g, 1 eq) was dissolved in 600 g of ethyl acetate at 50 ° C. Solid monoperephthalic acid (purity 95%, 249 g, 1.30 moles) was added in portions over an hour. By immersing the reaction flask in cold water the temperature of the stirred reaction mixture was maintained at 50 ° C. When the reaction Isothermal stopped, the flask was immersed in a hot bath and the reaction mixture was kept at 50 ° C for another two hours. After cooling to room temperature, the reaction mixture was filtered and the liquid washed with aqueous sodium carbonate and then with water The organic layer was concentrated under vacuum and dried at 80 ° C / 13 mbar to give 330 g of solid epoxy resin.

Melting temperature: 98 ° C

Oxirane content: 4.6% by weight

Iodine number: 2

Acid number: 0

Viscosity at 100 ° C: 970000 mPa.s

1700

Color 3 Gardner

Example 13

Preparation of a binder / hardener prepolymer from the epoxy ester of Example 2 and a carboxylated polyester

In a reactor equipped with a stirrer, 2 parts of the epoxidized polyester of example 2 were charged under a light flow of nitrogen and the temperature was increased up to 80-90 ° C until the epoxy ester melted, then 1 part was added. of Alftalati® 01634 carboxylated polyester resin (Vianova Resins) until complete homogenization of the resin was achieved. The temperature of the mixture was further increased to a maximum of 130-140 ° C and the mixture was kept at this temperature for about 15 minutes (upon prolonged heating, the mixture tends to gelatinize). After this time, the reaction mixture was rapidly discharged, cooled to room temperature and ground to give a prepolymer which can be used as a one-component binder or as a hardener in a two-component binder for powder coatings.

Example 14

Preparation of a binder / hardener prepolymer from the epoxy ester of Example 4 and from a carboxylic polyester.

The procedure of Example 13 was repeated with the epoxidized polyester of Example 4 using the same ratio of epoxide with respect to Alitala ® 01634.

Example 15

Preparation of a binder / hardener masterbatch from the epoxy ester of Example 8 and from a carboxylated polyester.

In a reactor equipped with a stirrer, 9.4 parts of the epoxidized polyester resin of Example 8 were charged under a light flow of nitrogen and the temperature was increased up to 80-90 ° C until the epoxide melted. In a second reactor equipped with a stirrer, 1 part of the Alftaìal® 01634 carboxylated polyester resin was charged under a light flow of nitrogen and the temperature was increased to about 130-140 ° C until the resin melted. Then the contents of the reactors were rapidly and thoroughly mixed while discharging them into the same container.After cooling and solidification, the mixture was ground to give a masterbatch which can be used as a one-component binder or as a hardener in a two-component binder for powder coatings.

Example 16

Preparation of a binder / hardener master mix from the epoxy resin of example 12 and from a carboxylated polyester.

The procedure of Example 15 was repeated using the epoxidized polyester resin of Example 12 and the same ratio of Alftalati® 01634 epoxide.

Example 17

Powder compositions for coating and coating tests carried out with such compositions

A series of powder coating tests were performed using the following powder compositions (in parts by weight). Each composition includes a two component binder which in turn comprises a reactive polyester resin ("Polyester") and a hardener containing epoxy groups ("Hardener"). For each binder composition used, except the reference one, the compound or composition used as hardener is identified by reporting the corresponding example number in parentheses.

The components used in the composition were:

Alftalai® 01634: carboxylated polyester resin, acid number - 35 mg KOH / g, Tg - 65 ° C

Alftala ^ AN 989: carboxylated polyester resin, acid number - 35 mg KOH / g, Tg - 60 ° C

Alftalal® AN 770: carboxylated polyester resin, acid number - 35 mg KOH / g, Tg - 50 ° C

Alftalai® AN 995: carboxylated polyester resin, acid number - 25 mg KOH / g, Tg - 55 ° C

Alitaial® VAN 997: carboxylated polyester resin, acid number d1 - 35 mg KOH / g, Tg - 55 ° C

Addito1®XL 496: flow promoting agent

(Alftalat and Additol are registered trademarks of Vianova Resins a company of the Hoechst group)

IrganojJ® 1010: antioxidant

(Irganox is a registered trademark of Ciba Ltd.)

Krono ^ ®2160: titanium dioxide filler

(Kronos is a registered trademark of NL Industries Ine.)

COMPOSITION OF REFERENCE

Polyester: Al phtala1® AN 989 569

Hardener: Araldit ^ ® PT 810 (= TGIC, Ciba) 43

Addi tol® XL 496 30

Irgano> f® 1010 3

Benzoin 5

Krono ^ ® 2160 350

Then ester / hardener ratio = 93/7

TEST NUMBER 1

Polyester: Alftala1® AN 770 465

Hardener: (Ex. 13) 155

Addi to ^ XL 496 30

Benzoin 5

Kronosi® 2160 345 Polyesteré / hardener ratio = 75/25

TEST NUMBER 2

Polyester: Alftala1® AN 770 465 Hardener: (Ex. 14) 155 Addito1® XL 496 30 Benzoin 5 Krono ^ ® 2160 345 Polyester / 1 hardener ratio = 75/25

TEST NUMBER 3

Polyester: Alftalatf®AN 770 465 Hardener: (Ex. 15) 155 Addltol® XL 496 30 Benzoin 5 Krono ^ ® 2160 345 Polyester / hardener ratio = 75/25

TEST NUMBER 4

Polyester: Alftala-é®AN 770 496 Hardener: (Ex.8) 124 Addito ^ ® XL 496 30 Benzoin 5 Krono ^ ® 2160 345 Polyester / 1 hardener ratio = 80/20

TEST NUMBER 5

Polyester: Alftalatf® VAN 995 496 Hardener: (Ex. 8) 124 Addito ^ ® XL 496 30 Benzoin 5 Krono ^ ® 2160 345 Polyester / 1 hardener ratio = 80/20

TEST NUMBER 6

Polyester: Al phthala1® AN 989 496 Hardener: (Ex. 8) 124 Addi to $> XL 496 30 Benzoin 5 Krono ^ ® 2160 345 Polyester / 1 hardener ratio = 80/20

TEST NUMBER 7

Polyester: Alftalati® VAN 997 496 Hardener: (Ex. 8) 124 Addito! ® XL 496 30 Benzoin 5 Krono ^ ® 2160 345 Polyester / hardener ratio = 80/20

TEST NUMBER 8

Polyester: Alitaial® AN 770 465 Hardener: (Ex. 16) 155 Additol® XL 496 30 Benzoin 5 Krono ^ ® 2160 345 Polyester / hardener ratio = 75/25

TEST NUMBER 9

Polyester: Alftala ^ AN 770 496

Hardener: (Ex. 12) 124

Additol® XL 496 30

Benzoin 5

Kronol® 2160 345

Polyester / hardener ratio = 80/20

TEST NUMBER 10

Polyester: Alftala1®AN 770 496

Hardener: (Ex.10) 124

Addito ^ ® XL 496 30

Benzoin 5

KronoP 2160 345

Polyester / hardener ratio = 80/20

The powders of the aforementioned compositions were extruded using the following conditions:

Twin screw extruder.

Temperature [° C]: 80/100/100 (3 heating elements)

Feed ratio [%]: 30

Rotation speed [min <-1>]: 300

The extrudate was cooled, micronized and ground (<125 μπι). The powder compositions thus obtained were used for painting tests.

The powder compositions were applied to steel panels by electrostatic spraying with a corona gun. The hardening was carried out in a convection oven at 200 ° C for 20-30 minutes. The results are shown in the following table 1.

TABLE 1

Evaluation 1: excellent, 2: good, 3: sufficient, 4: poor, 5: inadequate

(^ smoothness of the painted surface, determined visually

^ accelerated test of resistance to atmospheric agents according to ASTM G 53

(<3>) acetone scrub test, determined visually.

Claims (28)

CLAIMS 1. Solid epoxidized polyester resin comprising at least one epoxy ester containing per molecule two or more cycloaliphatic groups of general formula in which R * and R <4> are independently selected from the group consisting of hydrogen and methyl or R ^ and R <4> together are methylene, R ^ and R <3> are independently selected from the group consisting of hydrogen and methyl, said two or more cycloaliphatic groups being linked by open valences to groups independently selected from hydrogen, linear or branched alkyl Cj_g, alkanadiiH C2_g linear or branched ligands, alkentridiii C3-8 ligands (crosslinkers) linear or branched, alcantetrai-11 C4-8 ligands (crosslinkers) linear or branched and ligands or crosslinkers of general formula X (Y-) n where n is an integer from 2 to 4, X is a di-, tri- or tetravalent group containing at least one isocielic or heterocyclic ring and Y is a direct bond or - (CH2) m group in which m is an integer from 1 to 4, characterized in that it is substantially free from monomeric products. Solid epoxidized polyester resin according to claim I, wherein one of R * a R <4> is hydrogen or methyl and the remaining 1 of R <1> a R <4> are hydrogens. The polyester resin according to claim 1 wherein and together they are methylene, one of R <2> and R> <J> 3 is hydrogen or methyl and the other is hydrogen. 4. The solid epoxy polyester resin according to any one of claims 1 to 3, wherein the C ^ _g alkyls are selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and 2-ethylhexyl, the alkandiyl binders ( C2_g) are selected from the group consisting of 1,2-ethanediyl, 1,2-propanediyl, 1,3-propanediyl, 1,2-butanediyl, 1,3-butanediyl, 1,4-butanediyl, 2,3-butanediyl, 3 -methyl-1,3-butanediyl, 1,2-hexanediyl, 1,6-hexanediyl and 2,2-dimethyl-1,3-propane, the alkantryl Cg_g ligands (crosslinkers) are selected from the group consisting of 1.2.3 -propantryl and 2,2-dimethylbutan-1, r, Γ-triyl and the ligand C ^ -Cg alkantetrayls (crosslinkers) are selected from the group consisting of 1,2,3,4-butantetrayl and 2,2-dimethylpropane- 1.Γ, 1 <11>, 3-tetrayl. 5. Solid epoxidized polyester resin according to any one of claims 1 to 3, wherein the binding or cross-linking groups of general formula of X (Y-) n are isocyanurate groups of formula Solid epoxidized polyester resin according to any one of claims 1 to 5, characterized in that it has an acid number not higher than 2 mg KOH / g, preferably not higher than 1 mg KOH / g. 7. Process for preparing a solid epoxidized polyester resin according to any one of claims 1 to 6. comprising the steps of: i) reacting an unsaturated dicarboxylic acid or derivative of general formula wherein R <1> to R <4> are as defined in claim 1 and Q <1> and Q <2> are independently selected from the group consisting of hydroxy and alkoxy or Q <1> and Q <2> together are -0-, with at least one hydroxy compound selected from the group consisting of linear or branched C2_g alkandyls, linear or branched C3-8 alcohols, linear or branched C4_g alkantetraols and hydroxyl compounds of general formula X (Y-OH) n where n is an integer from Z to 4, X is a di-, tri- or tetravalent group containing at least one 1socielic or heterocyclic ring and each Y is a direct bond or - (CH2) m group where m is an integer from 1 to 4; and a linear or branched Cj_g alkanol, ii) essentially removing all mononomeric by-products, e iii) epoxidizing the resulting unsaturated polyester. 8. Process for preparing a solid epoxidized polyester resin according to any one of claims 1 to 6, comprising the steps of: i) reacting an unsaturated dicarboxylic acid or derivative of general formula wherein R * a are as defined in claim 1 and Q <1> e (r are alkoxy groups Cj.g, with at least one hydroxyl compound selected from the group consisting of linear or branched C2-8 alkandides, linear C3-8 alkantriols or branched, linear or branched C4-8 alkantetraols and hydroxy compounds of general formula X (Y-0H) n, where n is an integer from 2 to 4, X is a di-, tri- or tetravalent group containing at least one isocyclic ring or heterocyclic and each Y is a direct bond or group - (CH ^ - where m is an integer from 1 to 4, 1i) removing essentially all monomeric by-products, e ii) epoxy the resulting unsaturated polyester by reacting it with a peroxide compound. 9. Process according to claims 7 and 8, wherein the monomeric by-products are removed by vacuum distillation. 10. Process according to any one of claims 7 to 9, wherein the peroxidic compound is a peroxycarboxylic acid. 11. Process according to any one of claims 7 to 9, wherein the peroxy compound is hydrogen peroxide. Binder composition containing at least one solid epoxidized polyester resin according to any one of claims 1 to 6 and optionally at least one catalyst. 13. Composition according to claim 12 which additionally comprises at least one polymer capable of reacting with epoxy groups. 14. Composition according to claim 13, wherein the polymer capable of reacting with epoxy groups is selected from the group consisting of polymers containing carboxy groups, polymers containing anhydride groups, polymers containing hydroxyl groups, polymers containing amido and / or armino groups and polymers containing epoxy groups. 15. The composition of claim 14 wherein the polymer capable of reacting with epoxy groups is selected from the group consisting of modified polyesters, modified polyacrylates and modified polyethers. 16. Composition according to claim 15, wherein the polymer capable of reacting with the epoxy groups is a carboxylated polyester with an add number from 10 to 70 and a glass transition temperature from 50 to 70 ° C. 17. A composition according to any one of claims 13 to 16, wherein there is no substantial degree of crosslinking between said epoxidized polyester resin and said polymer capable of reacting with epoxy groups. 18. Composition according to any one of claims 13 to 16, wherein said epoxidized polyester resin and said polymer capable of reacting with epoxy groups are partially crosslinked. 19. A process for preparing a composition according to claim 17, comprising the steps of melting the epoxidized polyester resin and the polymer capable of reacting with the epoxy groups, mixing thoroughly at a temperature at which no substantial crosslinking takes place, solidifying and shred. 20. Process for preparing a composition according to claim 18, comprising the steps of melting the epoxy polyester resin and the polymer capable of reacting with the epoxy groups, mixing completely, maintaining at a high temperature for a time sufficient to obtain a partial crosslinking, solidify and mince. 21. One component thermosetting binder composition suitable for powder coating, comprising at least one solid epoxidized polyester resin according to any one of claims 1 to 6 or a composition according to any of claims 12 to 18. 22. Two-component thermosetting binder composition suitable for powder coating, comprising a hardener and a reactive polymer and, optionally, a catalyst, wherein the hardener comprises at least one solid epoxidized polyester resin according to any one of claims 1 to 6 or a composition according to any one of claims 13 to 18 and the reactive polymer comprises at least one polymer capable of reacting with epoxy groups. 23. Two-component thermosetting binder composition according to claim 22, wherein the polymer capable of reacting with epoxy groups is selected from the group consisting of carboxy group-containing polymers, anhydride group-containing polymers, hydroxyl group-containing polymers, amido group-containing polymers and / or armino and polymers containing epoxy groups. The two component thermosetting binder composition of claim 23, wherein the polymer capable of reacting with epoxy groups is selected from the group consisting of modified polyesters, modified polyacrylates and modified polyethers. 25. Two-component thermosetting binder composition according to claim 24, wherein the polymer capable of reacting with the epoxy groups is a carboxylated polyester with an acid number from 10 to 70 and a glass transition temperature from 50 to 70 ° C . 26. A powder coating composition comprising a thermosetting binder composition and one or more substances selected from the group consisting of pigments, catalysts, cross-linking agents, fillers and auxiliary materials, wherein the thermosetting binder composition is a composition according to any one of claims 21 to 25. 27. A process for preparing a partially or fully coated substrate by applying a powder coating composition according to claim 26 to a substrate and curing the coating by subjecting it to heat for a sufficient time at a temperature suitable to obtain a fully cured coating. Fully or partially coated substrate, wherein the coating is obtained from a binder composition according to any one of claims 12 to 18 and 21 to 25 or by a process according to claim 27.