WO2013124273A1

WO2013124273A1 - Thermosetting resin composition suitable for (re)lining

Info

Publication number: WO2013124273A1
Application number: PCT/EP2013/053279
Authority: WO
Inventors: Paul Sigston; Trijntje Maria BONNEMA; Johan Franz Gradus Antonius Jansen
Original assignee: Dsm Ip Assets B.V.
Priority date: 2012-02-20
Filing date: 2013-02-19
Publication date: 2013-08-29

Abstract

The present invention relates to a thermosetting, radically curable resin composition suitable for (re)lining comprising a.30 -70 wt.% of a methacrylate containing resin with a T_gof at least -5º C and at most 100º C, b.2.5 -20 wt.% of an unsaturated polyester resin comprising fumaric acid building blocks as unsaturated dicarboxylic acid building blocks and alkoxylated bisphenol A and/or alkoxylated bisphenol F building blocks as diol building blocks, c.1 -40 wt.% of at least one ethylenically unsaturated compound excluding benzyl methacrylate, which ethylenically unsaturated compound is able to copolymerize with (a), (b) and (d); d.5 –60 wt.% of benzyl methacrylate, the amounts are calculated as wt.% of the total weight of the compounds (a), (b), (c) and (d).

Description

THERMOSETTING RESIN COMPOSITION SUITABLE FOR (RE)LINING

The present invention relates to a thermosetting, radically curable resin composition containing methacrylate containing resin and being suitable for (re)lining.

Such resin compositions are known from WO-A-2008077586. With the herein described resin compositions, a good balance of properties relevant for (re)lining applications can be achieved.

In general, in order to be applicable for relining, the cured, unreinforced and unfilled resin composition must be able to achieve an E-modulus of at least 2 GPa (measured according to ISO 527-2), the elongation at break must be higher than 2% (measured according to ISO 527-2) and the tensile strength needs to be at a high level and the viscosity of the uncured, unfilled and unreinforced resin composition must be between 300 and 1000 mPa.s (measured according to ISO 3219 at 23°C). However, for (re)lining of tubes or pipes which are under pressure in order to be able to transport for example drinking water, thus for (re)lining of pressurized tubes or pipes, the tube or pipe with the (re)liner needs to be designed to withstand an internal pressure higher than atmospheric pressure, which can be up to 8 bar. In view of this, there is a desire to further increase the elongation at break of the cured, unreinforced and unfilled resin composition to preferably 3% or more, however without sacrificing E modulus significantly.

Accordingly, the object of the present invention was to design a thermosetting resin composition which is suitable to be applied for (re)lining with increased elongation at break of the cured, unreinforced and unfilled resin composition, however without sacrificing E modulus significantly.

This object has surprisingly been achieved in that the resin composition comprises

a. 30 - 70 wt.% of methacrylate containing resin with a T_g of at least -5°C and at most 100°C,

b. 2.5 - 20 wt.% of unsaturated polyester resin comprising fumaric acid building blocks as unsaturated dicarboxylic acid building blocks and alkoxylated bisphenol A and/or alkoxylated bisphenol F building blocks as diol building blocks,

c. 1 - 40 wt.% of ethylenically unsaturated compound, not being benzyl methacrylate, able to copolymerize with (a), (b) and (d); d. 5 - 60 wt.% of benzyl methacrylate,

the amounts are calculated as wt.% of the total weight of the compounds (a), (b), (c) and (d).

An additional advantage of the resin composition according to the invention is that the tensile strength can even be further increased.

EP1762581 A describes a curable resin composition useful in a lining material; the curable resin composition comprises (A) urethane-modified epoxy (meth)acrylate or unsaturated polyester and (B) monofunctional (meth)acrylate monomer. JP2007 291 179A also describes a curable resin composition useful to provide a tubular lining material; the curable resin composition comprises unsaturated polyester and a monofunctional (meth)acrylate monomer. WO2010/108939A describes a curable vinyl ester resin composition comprising vinyl ester resin and, as reactive diluent, methacrylate containing compound and an itaconate ester. These patent publications at least do not describe the presence of benzyl methacrylate in the curable resin composition.

As used herein, radically curable means that a network is formed via a radical (co)polymerisation.

In the framework of the present invention, (re)lining is understood to be the provision on the inside of a hollow object or system, such as a pipe system (for example a sewage system, industrial line system or a transport line), a vessel, a tank or a house sewer connection and the like, of a layer with a thickness of at least 2 mm, but usually more than 3 mm and even up to 30 - 40 mm. The layer thickness of a (re)lining is generally chosen to be thicker as the diameter of the hollow object increases. The (re)lining generally has the object of contributing to the mechanical strength and ensuring the resistance of the hollow object or system to chemicals, corrosion, etc., as well as prevention of leaks. It should be noted that when a hollow object or system is for the first time provided with a lining on the inside, this is referred to as lining. Each subsequent time that a hollow object or system that is already internally lined is provided again with a lining, this is called relining. The (re)lining therefore refers to all situations where the lining is provided either for the first time or for any subsequent time.

(Re)linings are clearly distinguished from so-called coating applications, for which the layer thickness generally amounts to a maximum of 0.5 mm and for which entirely different requirements are specified for the surface of the layer (and for the adhesion to the substrate). As a rule a coating will, for example, have to meet high requirements regarding surface quality and drying (in particular when being cured to the air), but will not contribute to the mechanical strength.

Thermosetting resin compositions harden by chemical reaction, often generating heat when they are formed, and cannot be melted or readily re-formed once hardened. The resin compositions are liquids at normal temperatures and pressures, so can be used to impregnate reinforcements, for instance fibrous reinforcements, especially glass fibers, and/or fillers may be present in the resin composition, but, when treated with suitable radical forming initiators, the various unsaturated compounds of the resin composition crosslink with each other via a free radical copolymerization mechanism to produce a hard, thermoset plastic mass (also referred to as structural part).

Preferably, the uncured, unreinforced and unfilled resin composition has a viscosity between 300 and 1000 mPa.s (measured according to ISO 3219 at 23 °C), more preferably between 300 and 800 mPa.s and even more preferably between 400 and 700 mPa.s.

The resin composition according to the invention comprises benzyl methacrylate in an amount of between 5 and 60 wt.%, preferably between 10 and 50 wt.% and more preferably between 15 and 45 wt.% (relative to the total weight of the compounds (a), (b), (c) and (d)).

Next to benzyl methacrylate, which is an ethylenically unsaturated compound able to copolymerize with (a) and (b), the resin composition according to the invention further comprises at least one other ethylenically unsaturated compound than benzyl methacrylate (compound(s) (c)), which ethylenically unsaturated compound(s) (c) is (are) able to copolymerize with (a) and (b) and preferably is (are) able to dilute (a) and (b). As used herein, compound(s) (c) is (are) able to dilute (a) and (b) means that mixing compound(s) (c) in an amount as present in the resin composition to a mixture of compounds (a) and (b) in amounts as present in the resin composition lowers the viscosity, at 23°C and atmospheric pressure, of such mixture of compounds (a) and (b).

The amount of ethylenically unsaturated compounds other than benzyl methacrylate and able to copolymerize with (a) and (b) and (d) (compound(s)

(c) ) is between 1 and 40 wt.%, preferably between 5 and 30 wt.% and more preferably between 10 and 25 wt.% (relative to the total weight of the compounds (a), (b), (c) and

(d) ).

Preferably, the resin composition comprises at least one methacrylate as compound (c). More preferably, compound (c) is a methacrylate or a mixture of methacrylates.

More preferably, the resin composition comprises at least one polymethacrylate as compound (c). More preferably, compound (c) is a

polymethacrylate or a mixture of polymethacrylates.

Even more preferably, the resin composition comprises at least one dimethacrylate as compound (c). More preferably, compound (c) is a dimethacrylate or a mixture of dimethacrylates. Preferably, the dimethacrylate is selected from the group consisting of 1 ,4-butanediol dimethacrylate, neopentylglycol dimethacrylate, PEG200 dimethacrylate, triethylene glycol dimethacrylate, tripropylene glycol dimethacrylate and any mixtures thereof. More preferably, the dimethacrylate is selected from the group consisting of 1 ,4-butanediol dimethacrylate, PEG200 dimethacrylate and mixtures thereof. Even more preferably, the resin composition comprises 1 ,4- butanediol dimethacrylate as compound (c).

In a preferred embodiment of the invention, the resin composition according to the invention comprises styrene in an amount less than 5 wt.%, more preferably in an amount less than 1 wt.% (relative to the total resin composition). Most preferably the resin composition is essentially styrene-free. Essentially free of styrene as used here means that the styrene concentration in the resin composition is lower than 0.01 wt% styrene (relative to the total resin composition).

The resin composition comprises at least one methacrylate containing resin with a glass transition temperature T_g of at least -5°C and preferably at most 100°C. The T_g is preferably at most 80 °C and more preferably at most 60 °C.

Preferably, the resin composition comprises methacrylate containing resin with a T_g of at least 0 °C, more preferably with a T_g of at least 5 °C. Preferably, the resin composition comprises methacrylate containing resin with a T_g of at least 5 °C ant at most 60 °C. As used herein, the glass transition temperature T_g is Tg_(mi_dpoint) as determined using Differential Scanning Calorimetry (DSC) according to IS01 1357 (edition 2009) with a heating rate of 5 °C/min.

The amount of methacrylate containing resins with a T_g of at least -5°C and at most 100 °C, in the resin composition according to the invention is between 30 and 70 wt.% (relative to the total weight of the compounds (a), (b), (c) and (d)), preferably between 35 and 65 wt.% and more preferably between 40 and 60 wt.%.

Preferably, the resin composition comprises methacrylate containing resin (a) that further contains an ether group and a hydroxyl group. More preferably, the methacrylate containing resin (a) present in the resin composition further contains an ether group and a hydroxyl group. The methacrylate containing resin (a) that further contains an ether group and a hydroxyl group is preferably obtained by reaction of an epoxy oligomer or polymer with methacrylic acid or methacrylamide, preferably with methacrylic acid. The methacrylate containing resin (a) that further contains an ether group and a hydroxyl group preferably comprises a moiety with the following structure

More preferably, the methacrylate containing resin (a) that further contains an ether group and a hydroxyl group comprises a moiety with the following structure

in which R-i is H or CH₃, preferably CH3.

The resin composition according to the invention comprises at least one unsaturated polyester resin (b) comprising fumaric acid building blocks as unsaturated dicarboxylic acid building blocks and alkoxylated bisphenol A and/or alkoxylated bisphenol F building blocks as diol building blocks. The amount of unsaturated polyester resins (b) comprising fumaric acid building blocks and alkoxylated bisphenol A and/or alkoxylated bisphenol F building blocks in the resin composition according to the invention is between 2.5 and 20 wt.% (relative to the total weight of the compounds (a), (b), (c) and (d)), preferably between 4 and 15 wt.% and more preferably between 5 and 12.5 wt.%.

Preferably, the unsaturated polyester (b) comprises propoxylated bisphenol A and/or propoxylated bisphenol F building blocks as diol building blocks; more preferably, the unsaturated polyester (b) comprises propoxylated bisphenol A as diol building blocks. Preferably, the amount of fumaric acid building blocks and alkoxylated bisphenol A and alkoxylated bisphenol F in (b) is such that the molar amount of alkoxylated bisphenol A and alkoxylated bisphenol F in (b) relative to the molar amount of fumaric acid building blocks in (b) is from 4:1 up to and including 1 :4. Preferably, the unsaturated polyester resins (b) present in the resin composition according to the invention preferably has a molecular weight M_n of higher than 2000 Dalton, more preferably higher than 2500 Dalton and even more preferably higher than 3000 Dalton and lower than 15000 Dalton, more preferably lower than 12500 Dalton and even more preferably lower than 10000 Dalton. Preferably, the unsaturated polyester resins (b) present in the resin composition according to the invention preferably has a molecular weight M_n in the range from 2000 to 15000 Dalton, more preferably in the range from 2500 to 12500 Dalton and even more preferably in the range from 3000 to 10000 Dalton. As used herein, the molecular weight of the resin is determined in tetrahydrofurane using gel permeation chromatography according to ISO 13885-1 employing polystyrene standards and appropriate columns designed for the determination of the molecular weights. The unsaturated polyester resins (b) preferably has an acid value in the range from 2 to 80mg KOH/g resin, more preferably in the range from 5 to 70 mg KOH/g resin. As used herein, the acid value of the resin is determined titrimetrically according to IS021 14-2000. The unsaturated polyester resin preferably has a hydroxyl value of at least 47 mg KOH/g resin, more preferably at least 50 mg KOH/g resin and even more preferably at least 60 mg KOH/g resin. As used herein, the hydroxy value of the resin is determined titrimetrically according to ISO 4629-1978.

Preferably, the average molecular weight per reactive unsaturation

(WPU) of the total amount of compounds (a), (b), (c) and (d) is higher than or equal to 190 and lower than or equal to 600.

In a preferred embodiment of the invention, the thermosetting resin composition comprises between 35 and 65 wt.% of compounds (a), between 4 and 15 wt.% of compounds (b), between 5 and 30 wt.% of compounds (c) and between 10 and 50 wt.% of benzyl methacrylate. In a more preferred embodiment of the invention, the resin composition comprises between 40 and 60 wt.% of compounds (a), between 5 and 12.5 wt.% of compounds (b), between 10 and 25 wt.% of compounds (c) and between 15 and 45 wt.% of benzyl methacrylate. Further details of compounds (a), (b), (c) and (d) and preferred compounds (a), (b), (c) and (d) are described above.

The resin composition according to the invention in addition optionally contains a filler in a weight ratio of 0.05:1 to 20:1 , preferably in a weight ratio of 0.2:1 to 3:1 , relative to the total weight of the compounds (a), (b), (c) and (d), the total of the weight percentages of the compounds (a), (b), (c) and (d) being 100. Suitable fillers are aluminium trihydrate, calcium carbonate, mica, microcrystalline silica, quartz powder, barite and/or talc.

The resin composition according to the invention in addition optionally contains fibers. Examples of fibers are natural fibers, inorganic or organic fibers.

In order to obtain curing of the thermosetting resin composition according to the invention, a radical initiator (e) is added to the resin composition as described above. The radical initiator (e) is added to the resin composition in such an amount that the amount of radical initiator in the resin composition is between 0.00001 - 5 wt%. Preferably this quantity lies between 0.1 and 5 wt% (relative to the total resin composition).

The radical initiator (e), which is applied in the resin composition according to the invention, is as a rule chosen from initiators which are suitable for thermal curing (thermal initiators), light curing (photo-initiators) or room temperature curing by means of redox initiation (redox initiators). Thermal curing is understood to be curing of the resin composition by means of heat. In case the resin composition is applied for relining, the heat is originating from heated water or gas (such as for example steam) used to pressurize the (re)lining. Photo-initiation is understood to be curing using irradiation with light of a suitable wavelength (photo irradiation). This is also referred to as light cure. In case of relining, the light energy is generally supplied via lamps placed or moved forward in the hollow objects.

In one embodiment of the invention, the initiator is a photo-initiator. In this embodiment the resin composition preferably comprises a cleavage type photo- initiator, more preferably a ohydroxy aryl ketone like for instance Irgacure 184, Irgacure 369, Darocure 1 173 (Ciba) or acyl phosphine oxides like for instance Lucerine TPO, Lucerine TPO-L (BASF), Irgacure 819 (Ciba) or mixtures thereof. Even more preferably, the photoinitiator is an acyl phosphine oxide. The acyl phosphine oxide is a mono acyl phosphine oxide or a bis acyl phosphine oxide. Most preferably, the photoinitiator is a bis acyl phosphine oxide. A preferred bis acyl phosphine oxide is bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (Irgacure 819). The quantity of photoinitiator is preferably between 0.1 and 2 wt.%, more preferably between 0.2 and 1 wt.%.

In another embodiment of the invention, the initiator is a thermal initiator. Examples of suitable thermal initiators are azo compounds like azo

isobutyronitril (AIBN) and derivatives thereof, and organic peroxides. The thermal initiator is preferably an organic peroxide, or a combination of two or more organic peroxides. Examples of suitable peroxides are, for instance, monoperoxy carbonates (also referred to as monopercarbonates) (of the formula -OC(O)OO-), peroxy dicarbonates (also referred to as dipercarbonate) (of the formula the formula

-OC(0)OOC(0)0-), peroxyesters (also referred to as peresters) (of the formula

-C(O)OO-), diacylperoxides (of the formula -C(0)OOC(0)-), dialkylperoxides (of the formula -00-), eto The peroxides can also be oligomeric or polymeric in nature. An extensive series of examples of suitable peroxides can be found, for instance, in US 2002/0091214-A1 , paragraph [0018]. The skilled person can easily obtain information about the peroxides and the precautions to be taken in handling the peroxides in the instructions as given by the peroxide producers. The thermal initiator is preferably selected from a perester, a perdicarbonate, a monopercarbonate or a mixture thereof.

In another embodiment of the invention, the initiator is a redox initiator. A preferred redox initiator is the combination of at least one transition metal compounds like for example Co, Cu, Mn, Fe compounds in combination with a hydroperoxide like for instance t-butyl hydroperoxide and cumenehydroperoxide, a perketal like for instance methyl ethyl ketone peroxide and acetylacetone peroxide, a perester like for instance t-butyl perbenzoate and a percarbonate, preferably in combination with an organic compound. The organic compound can be any organic compound that can be oxidized or reduced. Suitable examples are 1 ,2-dioxo compounds, 1 ,3-dioxo compounds, thiols, and N containing compounds like amides and amines. Preferably the organic compound is an N-containing compound.

Examples of N-containing compounds are dimethylaniline, diethylamide,

dimethylparatoluidine, diethylhydroxylamine, Ν,Ν-diethylacetoacetamide, benzyl amine, p-toluidine, 2-(N-ethylanilino)ethanol, triethanol amine, triethyl amine and Jeffamines, like for example Jeffamine D-2000. Still another preferred redox initiator is the combination of an tertiary aromatic amine like Ν,Ν-dimethylaniline, N,N-diethylaniline, N,N-dimethylparatoluidine, Ν,Ν-diisopropyltoluidine with a peranhydride like for instance di benzoyl peroxide (BPO) or di lauroyl peroxide.

For relining thermal curing or photo curing is preferred.

The resin compositions according to the invention may contain one or more inhibitors. The inhibitor (f) of the resin composition of the invention can be any radical inhibitor known to the skilled man, preferably chosen from the group of phenolic compounds, stable radicals like galvinoxyl and N-oxyl based compounds and/or phenothiazines. Suitable examples of inhibitors that can be used in the resin

compositions according to the invention are, for instance, 2-methoxyphenol, 4-methoxyphenol, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butylphenol, 2,4,6-trimethyl- phenol, 2,4,6-tris-dimethylaminomethyl phenol, 4,4'-thio-bis(3-methyl-6-t-butylphenol), 4,4'-isopropylidene diphenol, 2,4-di-t-butylphenol, 6,6'-di-t-butyl-2,2'-methylene di-p-cresol, hydroquinone, 2-methylhydroquinone, 2-t-butylhydroquinone,

2,5-di-t-butylhydroquinone, 2,6-di-t-butylhydroquinone, 2,6-dimethylhydroquinone , 2,3,5-trimethylhydroquinone, catechol, 4-t-butylcatechol, 4,6-di-t-butylcatechol, benzoquinone, 2,3,5,6-tetrachloro-l ,4-benzoquinone, methylbenzoquinone,

2,6-dimethylbenzoquinone, napthoquinone, 1 -oxyl-2,2,6,6-tetramethylpiperidine, 1 -oxyl-2,2,6,6-tetramethylpiperidine-4-ol (a compound also referred to as TEMPOL), 1 -oxyl-2,2,6,6-tetramethylpiperidine-4-one (a compound also referred to as TEMPON),

1 - oxyl-2,2,6,6-tetramethyl-4-carboxyl-piperidine (a compound also referred to as 4-carboxy-TEMPO), 1 -oxyl-2,2,5,5-tetramethylpyrrolidine, 1 -oxyl-2,2,5,5-tetramethyl-3- carboxylpyrrolidine (also called 3-carboxy-PROXYL), aluminium-N-nitrosophenyl hydroxylamine, diethylhydroxylamine, phenothiazine and/or derivatives or combinations of any of these compounds.

Advantageously, the amount of inhibitor in the resin composition according to the invention is in the range of from 0.00001 to 5 % by weight, preferably from 0.0001 to 2 % by weight, more preferably, from 0.001 to 1 % by weight (relative to the total resin composition). The type and amount of inhibitor depends on the type of curing. For example, in case of thermal curing 2,6-di-t-butyl-4-methylphenol and

2- methylhydroquinone are very suitable inhibitors.

The present invention also relates to a fiber mat comprising fibers impregnated with a resin composition as described above comprising compounds (a), (b), (c), (d) and (e).

The present invention further relates to a process for preparing a fiber reinforced composite article using a resin composition as described above comprising compounds (a), (b), (c), (d) and (e), wherein the process comprises mixing the compounds of said resin composition, impregnating fibers with this mixture and allowing the mixture to cure. In one embodiment, the fibers are present as a fiber mat, preferably a glass or carbon fiber mat.

The invention also relates to the use of the resin composition according to the invention comprising compounds (a), (b), (c), (d) and (e) in a flexible, sleeve-shaped object for use in (re)lining. According to the invention the flexible, sleeve-shaped objects contain a supporting or reinforcing material that is impregnated with the thermosetting, radically curable resin composition according to the invention, at least one of the surfaces of the sleeve-shaped object being provided with a barrier layer that is impermeable to the resin composition.

The supporting or reinforcing material of which the flexible, sleeve- shaped object consists is for example a fibrous web or needle felt of glass fibers, silica fibers, quartz fibers, carbon fibers, boron fibers, metal fibers, asbestos fibers, polyamide fibers (for example Kevlar^®of Du Pont), polyester fibers, cotton fibers, silk fibers, polyethylene fibers and jute fibers. The person skilled in the art can readily determine the suitable fibers for a specific application or desired property of the structural element to be formed. Carbon fibers are used for example for applications in which a low weight and a high rigidity are desirable.

The barrier layer that is impermeable to the curable resin composition and that is provided at least one of the surfaces of the sleeve-shaped object is a layer of polyethylene, polypropylene, polyamide etc.

The present invention also provides for a method for (re)lining a tube or pipe, tank or vessel with a flexible, sleeve-shaped object as described above, where

(a) the flexible, sleeve-shaped object is introduced into a tube, pipe, tank or vessel, and then

(b) is pressurized therein with (i) a liquid or (ii) a gas, so that the flexible, sleeve-shaped object is forced against the inside of the wall of the tube, the pipe, the tank or the vessel, and

(c) the curable resin composition comprising compounds (a), (b), (c), (d) and a thermal initiator which resin composition is present in the flexible, sleeve-shaped object is cured thermally in the case of (i) or (ii), or by photo-irradiation in the case of (ii).

The material from which a pipe, tube, tank or vessel itself is made can be chosen from a large series of suitable materials, for example cement, concrete, sandstone, GFK, polymer concrete, metal, steel, PVC, etc.

The present invention also relates to cured (re)liners for objects, in particular pipes, tubes, tanks or vessels, obtained by curing a resin composition according to the invention comprising compounds (a), (b), (c), (d) and (e). In case the resin composition comprises a thermal initiator, the curing is effected using thermal curing. In case the resin composition comprises a photo-inititiator, the curing is effected using photo curing. In a preferred embodiment of the invention, the cured (re)liner is used at a pressure higher than atmospheric pressure.

Finally, the present invention relates to the use of resin composition as described above in various applications such as for instance chemical anchoring, roofing, gel coats, containers, tanks, pipes, automotive parts, flooring, windmill blades, aviation, off shore applications. The present invention also relates to cured objects or structural parts obtained by mixing the compounds of a resin composition as described above comprising compounds (a), (b), (c), (d) and (e).

The invention will now be elucidated further on the basis of a few examples, without however being limited to the compositions shown in the examples and comparative experiments.

The Tg_(mi_dp₀i_nt₎ is measured using DSC according to IS01 1357 (edition 2009) with a heating rate of 5 °C/min. The test method for tensile testing (tensile strength, E-modulus, elongation at break) is according to ISO 527-2. The test method for viscosity measurement is according to ISO 3219 at 23°C.

Synthesis of resins

Resin A (methacrylate containing resin-compound (a) in the present application)

508 g epoxy resin with average mol mass of 350, 98 g diphenylol propane and 1.1 g tetra butyl phosphonium bromide were heated up to 1 10°C. After reaching exotherm, reaction was maintained at 1 15°C until EEW (epoxy equivalent weight) is approximately 330 g/epoxy. Thereafter, the mixture was cooled down to 1 10 °C, and 0.04 g inhibitor was added followed by 154 g methacrylic acid (dosing time 1 hr). Reaction was maintained until viscosity was 400 - 480 mPa.s (Cone & Plate at 125°C) and acid number was 10 - 16 mg KOH/g, WPU (average molecular weight per reactive unsaturation) was 425. Finally when spec has reached resin A is cooled down to 80°C. The Tg of resin A is 12.6°C.

This solid resin A is then dissolved in 1 ,4-butanediol dimethacrylate (compound (c) in the present application) (for relative amounts see Table). Resin B (unsaturated polyester- compound (b) in the present application)

Resin B, liquid at room temperature, was obtained by heating 913 g polyoxypropylene glycol bisphenol A, 87 g fumaric acid and 0.06 g hydroquinone within 2 hours to 210 °C with continuous stirring in a standard polycondensation reactor, use being made of a vacuum (to max. 0.1 bar): start of vacuum 1 hour after reaching 210 °C. The synthesis is ended at an acid number of < 20 mg KOH/g and a viscosity at 23 °C of < 4 dPa.s. The resin has a WPU of 1338.

This resin B is diluted with benzyl methacrylate (compound (d) in the present application) (for relative amounts see Table). Resin C (methacrylate containing resin-compound (a) in the present application)

362 g epoxy resin with average mol mass of 350 is heated up to 100°C, continuously stirring using oxygen sparge and nitrogen blanket. At this temperature, 40 g of methacrylic acid, 0.1 g chromium chloride and 0.08 g hydrochinon are added. After 15 minutes everytime 3 x 40 g of methacrylic acid is added. Reaction is maintained and synthesis is ended at an acid number < 5 mg KOH/g and EEW (epoxy equivalent weigth of 5000 - 8000 g/epoxy. After reaching the end point the resin (having a WPU of 280); hereinafter referred to as resin C) is cooled down. The Tg of resin C is 0.2°C.

This solid resin C is then dissolved in 1 ,4-butanediol dimethacrylate and PEG200DMA (both compound (c) in the present application) (for relative amounts see Table).

Resin D (unsaturated polyester- compound (b) in the present application)

Resin D, liquid at room temperature, was obtained by heating 938 g polypropylene glycol bisphenol A, 89 g fumaric acid and 0.12 g hydroquinone within 2 hours to 210 °C with continuous stirring in a standard polycondensation reactor, use being made of a vacuum (to max. 0.1 bar): start of vacuum 1 hour after reaching 210 °C. The synthesis is ended at an acid number of < 20 mg KOH/g and a viscosity at 23 °C of < 4 dPa.s. The resin D has a WPU of 1338.

Example l and comparative experiments A-F

Formulations were prepared according to table 1 (amounts given are wt.%). The compounds were mixed at room temperature and the viscosities

determined. Thereafter, in Comparative Experiments A-D and Example 1 , the mixture was cured at 60°C using 1 % tert-butyl peroxybenzoate , 0.8% bis(4-tert- butylcyclohexyl) peroxydicarbonate and 1 % of a 1 % cobalt (II) 2-ethylhexanoate accelerator. In Comparative Experiments E and F, the mixture was cured at room temperature using 0.2% of a 10% solution of cobalt(ll) octoate, 1.0% of a 10% solution of dimethyl aniline and 2.0% methylethylketon peroxide (Butanox M50) followed by a postcure of 24 hours at 60 °C and 24 hours at 80 °C, according to the procedure according to WO-A-2008077586. After curing the tensile properties were determined. The following abbreviations are used:

1 ,4-BDDMA=1 ,4-butanediol dimethacrylate (molecular weight M_n 226) obtained from Aldrich,

BNMA= Benzyl methacrylate (molecular weight M_n 176) obtained from Aldrich.

PEG200DMA= polyethyleneglycol dimethacrylate (molecular weight M_n 330) obtained from Aldrich. 28454-EP-EPA - 14 -

Table

As the cured resin composition of Comparative Experiment E has an elongation at break of higher than 2%, an E-modulus of more than 2 GPa, a high tensile strength and as the viscosity of the uncured resin composition is between 300 and 1000 mPa.s, a resin composition according to the state of the art that is used in Comparative Experiment E is suitable for being applied in (re)lining of tubes or pipes. However, for (re)lining of tubes or pipes which are under pressure, it would be beneficial to be able to increase the elongation at break, however without significantly sacrificing the E-modulus. As shown in Example 1 , using the combination of compounds according to the invention surprisingly results in an increase of the elongation at break without losing E-modulus too much, while the tensile strength is even increased.

Comparing Comparative Experiments A-D with Example 1 shows that the combination of compounds (a), (b), (c) and (d) as claimed is needed to obtain an increase of the elongation at break without significantly sacrificing the E-modulus and further shows that the elongation at break can surprisingly be increased without significantly sacrificing the E-modulus:

Comparing Comparative Experiment B and C with Comparative Experiment A shows that adding resin B (compound (b)) to a mixture of compound (a) and (c) results in that the elongation at break remains the same or increases to a small extent (+20%).

Comparing Comparative Experiment D with Comparative Experiment A shows that adding BNMA (compound (d)) to a mixture of compound (a) and (c) results in that the elongation at break decreases (-27%).

Very surprisingly when adding compound (b) and compound (d) to a mixture of compound (a) and (c), the elongation at break remarkably increases (+ 155%) and without significantly sacrificing the E-modulus. The elongation at break increases to more than 3%, while the E modulus is maintained at a level higher than 2 GPa, even higher than 2.5 GPa. Furthermore, the tensile strength is even increased. As the elongation at break is higher than 3% and the E modulus is even higher than 2.5 GPa, the resin composition is able to result in superior relining performance under high pressure.

Claims

Thermosetting, radically curable resin composition suitable for (re)lining comprising

a. 30 - 70 wt.% of a methacrylate containing resin with a T_g of at least -5°C and at most 100°C,

b. 2.5 - 20 wt.% of an unsaturated polyester resin comprising fumaric acid building blocks as unsaturated dicarboxylic acid building blocks and alkoxylated bisphenol A and/or alkoxylated bisphenol F building blocks as diol building blocks,

c. 1 - 40 wt.% of at least one ethylenically unsaturated compound

excluding benzyl methacrylate which ethylenically unsaturated compound is able to copolymerize with (a), (b) and (d);

d. 5 - 60 wt.% of benzyl methacrylate,

Thermosetting resin composition according to claim 1 , wherein the resin composition comprises at least one dimethacrylate as compound (c).

Thermosetting resin composition according to claim 2, wherein the resin composition comprises a dimethacrylate selected from 1 ,4-butanediol dimethacrylate, neopentylglycol dimethacrylate, PEG200 dimethacrylate, triethylene glycol dimethacrylate and/or tripropylene glycol dimethacrylate. Thermosetting resin composition according to claim 2, wherein the dimethacrylate is selected from 1 ,4-butanediol dimethacrylate and/or PEG200 dimethacrylate.

Thermosetting resin composition according to anyone of the previous claims, wherein the resin composition comprises styrene in an amount lower than 0.01 wt.% (relative to the total resin composition).

Thermosetting resin composition according to anyone of the previous claims, wherein the methacrylate containing resin (a) is obtained by reaction of an epoxy oligomer or polymer with methacrylic acid or methacrylamide, preferably with methacrylic acid.

Thermosetting resin composition according to anyone of the previous claims, wherein the methacrylate containing resin (a) is a resin comprising a moiety with the following structure

8. Thermosetting resin composition according to anyone of the previous claims, wherein the methacrylate containing resin (a) is a resin comprising a moiety with the following structure

in which R-i is H or CH₃, preferably CH3.

9. Thermosetting resin composition according to anyone of the previous claims, wherein compound(s) (c) is (are) able to dilute (a) and (b).

10. Thermosetting resin composition according to anyone of the previous claims, wherein the unsaturated polyester (b) comprises propoxylated bisphenol A building blocks as diol building blocks.

1 1 . Thermosetting resin composition according to anyone of the previous claims, wherein the resin composition comprises between 40 and 60 wt.% of compound (a), between 5 and 12.5 wt.% of compound (b), between 10 and 25 wt.% of compound (c) and between 15 and 45 wt.% of benzyl methacrylate (d).

12. Thermosetting resin composition according to anyone of the previous claims, wherein the resin composition further comprises radical initiator (e) in an amount of between 0.1 and 5 wt% (relative to the total resin composition) and the radical initiator is a photo-initiator or a thermal initiator or a redox initiator.

13. Fiber mat comprising fibers which fibers are impregnated with a resin

composition according to claim 12.

14. Cured (re)liners obtained by curing a resin composition according to claim 12. 15. Use of a cured (re)liner according to claim 14 at a pressure higher than

atmospheric pressure.

16. Use of a resin composition according to claim 12 in the field of chemical anchoring, roofing, gelcoats, containers, tanks, pipes, automotive parts, flooring, windmill blades, aviation, off shore applications.

Cured objects or structural parts obtained by mixing the compounds of a resin composition according to claim 12.