GB2491643A

GB2491643A - Method of forming a polymeric material on a substrate

Info

Publication number: GB2491643A
Application number: GB1109755.7A
Authority: GB
Inventors: David George Anderson; Alan Thomas Rose
Original assignee: Lambson Ltd
Current assignee: Lambson Ltd
Priority date: 2011-06-10
Filing date: 2011-06-10
Publication date: 2012-12-12
Also published as: WO2012168694A1; GB201109755D0

Abstract

Apparatus for producing an activated polymerisable formulation includes a receptacle (not shown) for containing the polymerisable formulation. The formulation is fed by a pump (not shown) through a pipe 4 as represented by arrows 6 and into a static mixer 8. Walls which define the static mixer are transparent to UV radiation so that fluid within the static mixer can be subjected to UV radiation by use of an irradiation device which surrounds the static mixer. Downstream of mixer 8, the fluid passes into a pipe 12 and via a nozzle 14 can be directed to a desired location. The polymerisable formulation is suitably an epoxy or urethane-based system. The apparatus may be used in the repair of cavities in structures, for example airport runway aprons.

Description

I

POLYMERIC MATERIALS

This invention relates to polymeric materials and particularly, although not exclusively, relates to the production of a polymeric material on a substrate, for example to fill cavities or to coat a surface, such as an internal surface of a pipe.

The polymerisation of coating materials using UV or visible light with photoinitiators or electron beams to form free radicals or to generate acidic or basic catalysts is well known. Generally these irradiation techniques are used in applying coatings to surfaces where the applied coat will be less than 100 microns and preferably less than microns thick. This restriction applies due to the penetration of radiation into the coating being retarded by the coating material itself and by any fillers or pigments that may be incorporated in the material. The physical restriction to penetration by radiation may have several detrimental side effects such as: 1) Cure of the coating tends to occur from the surface down. This may cause differential shrinkage and, because the coating material in contact with the substrate may not be fully cured, poor adhesion can result.

2) The retarded penetration of radiation may mean that, to achieve full cure, will require extensive exposure times. This furthermore, has the potential to create local high and detrimental temperatures and extend the overall process time to uneconomic levels.

The aforementioned problems have been addressed as described in US2006/0108450 which relates to a spray gun having a spray nozzle, wherein an actinic radiation outlet is positioned externally so as to direct radiation at spray produced by the nozzle. The radiation initiates polymerisation of a polymerisable formulation being sprayed. Disadvantageously, however, the radiation may incompletely activate the polymerisable formulation and/or activation may vary according to the spray pattern used. Consequently, control of the activation may be difficult. In addition, the UV radiation used may pose a serious hazard to operators and/or be difficult to contain.

It is an object of the present invention to address the above-described problems.

According to a first aspect of the invention, there is provided a method of forming a polymeric material on a substrate, the method comprising the steps of: (i) causing a polymerisable formulation to flow in a turbulent and/or tortuous manner; and (ii) subjecting the polymerisable formulation to actinic radiation whilst it is flowing in said turbulent and/or tortuous manner.

The method may include providing the polymerisable formulation in a flow path between a first position and a second position, said second position being downstream of said first position. Said flow path is suitably arranged to cause the formulation to flow in said turbulent and/or tortuous manner. Said flow path may be convoluted. It may include baffles to alter the direction of movement of said fluid moving between said first and second positions. Said flow path is preferably arranged to cause fluid flowing between said first and second positions to move transverse to a straight line linking the first and second positions. Said flow path is preferably defined by a flow device. The flow device suitably includes no moving parts which are arranged to contact fluid passing through the flow device. All parts of the flow device preferably remain stationary on contact with fluid flowing through the flow device.

Said method suitably includes using a static mixer to cause the formulation to flow in said turbulent and/or tortuous manner. Thus, said flow device suitable comprises a static mixer.

Said flow device may have a fluid inlet and a fluid outlet. The distance between the inlet and outlet may be less than im, less than 75cm, less than 50cm or less than 40cm. The distance may be at least 5cm or at least 10cm. The area defined by said fluid inlet into which fluid can pass may be at least 0.5cm2, preferably at least 1cm2.

The area may be less than 10cm2, less than 8cm2, less than 5cm2, or less than 3cm2.

A housing which suitably defines the flow path between said first and second positions, when provided, may be transparent, at least in part, to said actinic radiation so that polymerisable formulation flowing in said flow path can be irradiated, suitably from a position outside the flow path and/or outside said housing. When, as is preferred, the method uses a static mixer, said static mixer is preferably transparent to said actinic radiation, at least in part. Whilst it would be possible for the housing and/or static mixer to include "windows" which are transparent to said actinic radiation, with areas around the window(s) being substantially opaque (or less transparent), it is preferred for substantially the entire housing and/or substantially the entire static mixer to be transparent to said actinic radiation. In a preferred embodiment, at least 80% (preferably at least 95%) of the weight of the static mixer comprises a material or materials which is/are transparent to actinic radiation. The transparency referred to is suitably such that a UV activatable compound in said polymerisable formulation flowing within the housing and/or static mixer can be activated by directing actinic radiation through transparent region(s) of the housing and/or mixer.

The actinic radiation is suitably able to initiate a chemical reaction in said polymerisable formulation. The wavelength suitably depends on the nature of the polymerisable formulation. Generally, visible light and ultraviolet (UV) radiation have suitable wavelengths. Particularly suitable wavelengths of the actinic radiation are below 600 nm, in particular below 500 nm, and especially below 450 nm. Suitably sources of actinic radiation to be used are commercially available, As examples fluorescent tubes, deuterium halogen light sources, laser light sources, mercury vapour lamps, mercury-xenon lamps and metal halide lamps may be mentioned. In addition to lamps which continuously provide actinic radiation, it is also possible to use discontinuous sources of actinic radiation, such as Xenon flash lamps or pulsed lasers. Preferably, the actinic radiation is provided by one or more light emitting diodes, especially UV LEDs.

The method preferably comprises directing radiation in a first direction towards said polymerisable formulation and directing radiation in a second direction towards said polymerisable formulation. Preferably, the angle defined between said first and second directions is in the range 10 to 180°. As will be appreciated, when the angle is 180° the first and second directions are opposite one another. The method may include directing radiation towards said polymerisable formulation in a third direction which is suitably positioned between said first and second directions. Said third direction may be define an angle in the range 20 to 120° to said first direction and suitably also to said second direction. The method may include directing radiation towards said polymerisable formulation in a fourth direction, wherein the angle between the third and fourth directions is suitably in the range 10 to 180°.

When said polymerisable formulation flows in said flow path defined by a flow device, radiation is suitably directed from positions spaced around the flow path. Radiation is suitably directed in said first, second, third and/or fourth directions from respective first, second, third and fourth positions spaced around the flow path. Preferably radiation is directed at the polymerisable formulation so that radiation impinges at least 180° (preferably at least 270°) of a circumference which extends around the flow path of the polymerisable formulation. Preferably, radiation impinges substantially the entirety of a circumference which extends around the flow path.

Preferably, radiation is directed at least 1cm, suitably at least 2.5cm, preferably at least 5cm, more preferably at least 7.5cm along the direction of the flow path.

Radiation may be directed less than 25cm, or less than 15cm along the direction of the flow path.

Preferably, radiation is directed so as to define a cylinder of radiation axially aligned with and surrounding the flow path.

Said actinic radiation is suitably arranged to initiate or accelerate polymerisation of the polymerisable formulation. Preferably, it is arranged to initiate polymerisation. Said radiation is preferably applied from a user-operable radiation source. Said radiation applied in step (ii) is preferably additional to any natural radiation to which said polymerisable formulation may be subjected.

Said actinic radiation is suitably arranged to activate a component of the polymerisable formulation.

Said polymerisable formulation may include a first component which is arranged to initiate polymerisation of the polymerisable formulation. It may be an initiator for cationic or base catalysed polymerisation. Said initiator may be such that, once generated by radiation, it remains active (preferably for at least 5 minutes) (i.e. it is able to initiate polymerisation) even after removal of the source of radiation. Said first component may be a catalyst.

Said polymerisable formulation may include a second component which may be a photosensitizer. Such a photosensitizer is suitably arranged to absorb radiation in step (ii) and facilitate transfer of energy to said first component so that said first component is able to initiate polymerisation. Said second component may include an anthracene, pyrene, carbazole, thiazine, phenothiazine or thioxanthone moiety.

Preferably, the said second component includes an anthracene, thiazine, phenothiazine or thioxanthone moiety. Said second components are suitably selected to be sensitizing to the first component which is a photoinitiator. For example, when the photoinitiator is capable of generating a cationic catalyst, it may comprise a triarylsulphonium salt of a strong Lewis acid such as hydrogen hexafluoro -phosphate or -antimonate and then dialkoxyanthracene could be a second component in the form of a sensitizer. In the case when the photoinitiator comprises a diaryl iodonium salt of the said Lewis acids then thioxanthones such as isopropylthioxanthone act as suitable sensitizers. In the case of base catalysed polymerisations, the starting initiator could be Speedcure 97 or Ciba specialties Products PLA I and 2 and such would be used with a polymerisable mixture of a thiol and an isocyanate, where such materials would be oligomeric and of viscosities suitable for application.

Said polymerisable formulation may include a third component which comprises a polymerisable compound, for example a monomer. Said third component may comprise an epoxy, thiol or isocyanate compound. When the polymerisable formulation is arranged to be base catalysed, said third component may comprise a thiol (e.g a polythiol) or an isocyanate (e.g. a polyisocyanate).

Said polymerisable formulation may include a fourth component which may be a comonomer or reactive diluent.

Said polymerisable formulation may include a fifth component which may comprise one or more fillers. Said fillers may comprise particulate fillers or fibrous fillers.

Preferred fillers are inorganic. Preferred fillers are particulate. Examples of fillers include precipitated or ground calcium carbonate, silica flour, fumed silica and bentonite.

Said polymerisable formulation may include further components, for example stabilisers such as biocides, plasticisers and anti-oxidants.

The ratio of the total weight of all monomers in the polymerisable formulation to the total weight of all first components may be at least 100, preferably at least 150. The ratio may be less than 500, 400 or 300.

When the polymerisable formulation includes a third component and a fourth component, the ratio of the weight of third component to the weight of fourth component may be at least 2, preferably at least 2.5, and may be less than 10, preferably less than 7, more preferably less than 5.

Preferably, said polymerisable formulation includes a said third component which is preferably an epoxy compound. Said third component is preferably a glycidyl compound for example a glycidyl ether, and/or it may be a cycloaliphatic epoxy compound. Examples include neopentylglycidylether, 3,4-epoxy cyclohexyl methyl- 3,4-epoxy cyclohexane carboxylate, and diglycidylethers of bisphenol A or F. Preferably, said polymerisable formulation includes a said fourth component (preferably in conjunction with said preferred third component in the form of an epoxy compound) which may comprise an epoxy, oxetane, di-or multifunctional polyol.

In an especially preferred embodiment, said polymerisable formulation includes a third component which is an epoxy compound, a fourth component which is an oxetane or polyol, a first component which is a cationic catalyst and an optional second component which is a photoinitiator.

Preferably, said polymerisable formulation is arranged to produce an epoxy or polyurethane polymer.

In the method, polymerisation of the polymerisable formulation is suitably initiated in step (ii) but the polymerisation is suitably slow enough to allow the polymerisable formulation to be contacted with a substrate, before the viscosity of the polymerisable formulation becomes too high. Preferably, the method includes the step of contacting activated polymerisable formulation with a substrate after step (ii). The method may include spraying the activated polymerisable formulation at a substrate or delivering a stream or slug of activated polymerisable formulation at the substrate, for example using a gun (or the like). The method suitably does not involve an operator subjecting the activated polymerisable formulation to additional actinic radiation after contact with the substrate. Suitably, the only radiation to which the activated polymerisable formulation is subjected after contact with the substrate is ambient radiation.

The method may comprise forming a coating of polymerised and/or cured polymerisable formulation on said substrate and/or the polymerisable formulation may be arranged to enter, for example fill, an opening in the substrate, for example in a surface thereof. In one embodiment, the substrate may comprise a curved surface, for example of a cylindrical member, for example a pipe (or the like) and the polymerisable formulation may be directed towards said surface (which may be an internal surface) in the method. In another embodiment, said substrate may comprise an electronics component and the method may be arranged to define a layer of the component.

When the method is arranged to fill an opening in the substrate, said polymerisable formulation may be directed into the opening. Said opening may comprise a defect in the substrate in need of repair for example a material subjected to traffic such as an aircraft runway.

The thickness of the material on the substrate may be from 100pm to 100cm, preferably in the range 100pm to 10cm.

According to a second aspect of the invention, there is provided apparatus for forming a polymeric material on a substrate, (for example for use in the method of the first aspect), the method comprising: (a) a flow device arranged to cause a polymerisable formulation to flow in a turbulent and/or tortuous manner; (b) radiation means for subjecting polymerisable formulation in said flow device to actinic radiation.

Said flow device is suitably as described according to the first aspect. It is preferably a static mixer. It is preferably transparent at least in part to actinic radiation from said radiation means.

Said radiation means preferably comprises a first array of radiation emitting elements.

Said first array is preferably elongate and preferably extends in the direction of flow of polymerisable formulation through the flow device. Said radiation means may include a second array of radiation emitting elements. Said second array is preferably elongate and preferably extends in the direction of flow of polymerisable formulation through the flow device. Said first and second arrays are preferably arranged to direct radiation in said first and second directions as described according to the first aspect.

Said radiation means may comprise a third array of radiation emitting elements. Said third array is preferably elongate and preferably extends in the direction of flow of polymerisable formulation through the flow device. Said radiation means may comprise a fourth array of radiation emitting elements. Said fourth array is preferably elongate and preferably extends in the direction of flow of polymerisable formulation through the flow device. Said third and fourth arrays are preferably arranged to direct radiation in said third and fourth directions as described according to the first aspect.

Said apparatus preferably includes one or more receptacles for containing components of the polymerisable formulation which are arranged to deliver polymerisable formulation to the flow device.

Downstream of the flow device, said apparatus suitably comprises a dispensing device which is suitably arranged to dispense polymerisable formulation (after irradiation) onto a substrate. The dispensing device may comprise a user-operable control (e.g. a trigger) for opening and/or closing a dispensing orifice of the dispensing device.

Any feature of any aspect of any invention or embodiment described herein may be combined with any feature of any aspect of any other invention or embodiment described herein mutatis mutandis.

Specific embodiments of the invention will now be described, by way of example, with reference to accompanying drawings, in which: Figure 1 is a schematic representation of part of apparatus used in producing an activated polymerisable formulation; Figure 2 is an end view of an irradiation device of the apparatus; Figure 3 is a side elevation of the irradiation device in the direction of arrow Ill of Figure 2; Figure 4 is a cross-section along line IV-IV of Figure 2; and Figure 5 is an end view of an alternative irradiation device.

Referring to Figure 1, apparatus for producing an activated polymerisable formulation includes a receptacle (not shown) for containing the polymerisable formulation. The formulation is fed by a pump (not shown) through a pipe 4 as represented by arrows 6 and into a static mixer 8. Walls which define the static mixer are transparent to UV radiation so that fluid within the static mixer can be subjected to UV radiation by use of an irradiation device 10 which surrounds the static mixer. Downstream of mixer 8, the fluid passes into a pipe 12 and via a nozzle 14 can be directed to a desired location.

The apparatus is described in greater detail below.

The static mixer 8 may be of a conventional design. It is suitably arranged to cause the polymerisable formulation to flow in a tortuous, convoluted and/or turbulent manner so that substantially the entire volume of polymerisable formulation flowing through the mixer 8 is subjected to UV radiation from irradiation device 10 and/or substantially the entire amount of UV activatable components in the polymerisable formulation are activated by UV radiation during passage through the mixer. Thus, the fluid leaving the static mixer suitably comprises a substantially homogenous mass of UV activated polymerisable formulation.

The static mixer suitably includes a series of fixed baffles 16 within a housing 18. The baffles are arranged to produce patterns of flow division and radial mixing. The housing and suitably also the baffles are made from a substantially UV transparent material (e.g. a plastics material) so that radiation from device 10 can pass into the fluid within the mixer.

The irradiation device 10 is suitably arranged to direct a substantially cylindrical envelope of radiation to impinge fluid within the static mixer. To this end, as shown in the Figure 2, the static mixer 8 is surrounded by elongate housings 20a-e, each of which incorporate arrays of LEDs 26, as shown in Figure 4. The LEDs may be arranged in a single row (as shown in Figure 4) or multiple rows may be provided.

In the Figure 2 embodiment, five housings 20 are shown arranged at each apex of a pentagon. Other arrangements may be provided in order to define a substantially cylindrical radiation envelope. For example, as shown in Figure 5, six housings 20 may be arranged at the apexes of a hexagon.

In one embodiment, all LEDs in the arrays may be lit at once. However, in other embodiments, for example wherein it is desired to apply a lower level of UV radiation, only some LEDs in an array may be lit and/or only some LEDs in respective housings may be lit.

Typically, the static mixer may have a length of about 25cm. The diameter of the static mixer (and suitably also of pipe 4) is about 1.3cm.

The static mixer 8 may extend a short distance downstream of device 10 as represented by region 30 in Figure 1.

Although the polymerisable formulation is described as being pumped from a single receptacle, components of the formulation may be held in different receptacles and mixed upstream of mixer 8, before being pumped along pipe 4.

Operation of apparatus 2 and the selected polymerisable formulation are such that, after activation of the polymerisable formulation, the formulation does not fully cure until after it has been delivered to a substrate via nozzle 14. Thus, the formulation is sufficiently fluid after activation to afford sufficient time for it to be contacted with a substrate. Only after such contact does the formulation fully cure.

The polymerisable formulation may be sprayed from nozzle 14 or otherwise dispensed. In one embodiment, the polymerisable formulation may be used for filling cavities or other openings. Cavities which may be filled as described may comprise defects which need to be repaired rapidly. For example, the process described may be used in the repair of cavities in airport runway aprons. The relatively rapid cure of a polymerisable formulation applied in the process described may reduce the downtime of a runway, with potential cost savings.

In a second embodiment, the polymerisable formulation may be used in remedial coating of the inside of pipes or pipelines. In the process, a thin layer of a polymerisable formulation may be sprayed from a position within a pipe to a surface to be coated. Pipes may be coated along their lengths using mobile pigs which travel along the pipes spraying formulation.

In another embodiment, the polymerisable formulation may be used for industrial flooring.

The apparatus may be used with any polymerisable formulation which is activatable by irradiation and wherein cure of the formulation is slow enough to enable the activated formulation to be contacted with a substrate. The polymerisable formulation may advantageously be an epoxy or urethane-based system. The polymerisable formulation suitably includes a catalyst which is activated by UV radiation. It may comprise arylsulphonium or iodonium hexafluorophosphates/antimonates; or a photolatent base such as described in W02008/1 19688 A for use with thioltisocyanate systems.

Specific polymerisable formulations are provided in the examples below.

Example I -Epoxy-based 81.6% Cycloaliphatic epoxide resin (Uvicure SIlO) 15.3% Reactive oxetane diluent (TMPO) 3.05% Triarylsulphonium hexafluoroantimonate (Speedcure 976s) 0.05% Dialkoxyanthracene Example 2 -Polyurethane-based Isocyanate -I equivalent Thiol (monomeric or polymeric) -I equivalent Morpholine-based catalyst -0.1 to 0.5% on weight of mixture.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

Claims 1. A method of forming a polymeric material on a substrate, the method comprising the steps of: (i) causing a polymerisable formulation to flow in a turbulent and/or tortuous manner; and (ii) subjecting the polymerisable formulation to actinic radiation whilst it is flowing in said turbulent and/or tortuous manner.
2. A method accordingly to claim 1, which includes providing the polymerisable formulation in a flow path between a first position and a second position, said second position being downstream from said first position and wherein said flow path is arranged to cause the formulation to flow in said turbulent and/or tortuous manner.
3. A method according to claim 2, wherein said flow path includes baffles to alter the direction of movement of said fluid moving between said first and second positions.
4. A method according to any preceding claim, which includes a static mixer to cause the formulation to flow in said turbulent and/or tortuous manner.
5. A method according to any of claims 2 to 4, wherein said flow path has a fluid inlet and a fluid outlet, wherein the distance between the inlet and outlet is less than 1 metre and is at least 5cm.
6. A method according to claim 5, wherein the area defined by said fluid inlet into which fluid can pass is at least 0.5cm2 and less than 10cm2.
7. A method according to any of claims 2 to 6, wherein a housing which defines the flow path between said first and second positions is transparent, at least in part, to actinic radiation.
8. A method according to any preceding claim, which uses a static mixer to cause said polymerisable formulation to flow in a turbulent and/or tortuous manner, wherein said static mixer is transparent to said actinic radiation.
9. A method according to any preceding claim, which comprises directing radiation in a first direction towards said polymerisable formulation and directing radiation in a second direction towards said polymerisable formulation, wherein the angle defined between said first and second directions is in the range 10 to 1800.
10. A method according to claim 9, the method including directing radiation towards said polymerisable formulation in a third direction which is positioned between said first and second directions, said third direction defining respective angles in the range to 120° to said first direction and to said second direction.
11. A method according to any of claims 2 to 10, wherein radiation is directed over a length of at least 1cm and less than 25cm along the direction of the flow path.
12. A method according to any preceding claim, wherein said actinic radiation is arranged to activate a component of the polymerisable formulation.
13. A method according to any preceding claim, wherein said polymerisable formulation includes a first component which is arranged to initiate polymerisation of the polymerisable formulation, wherein said first component is an initiator for cationic or base catalysed polymerisation.
14. A method according to any preceding claim, wherein said polymerisable formulation includes a second component which is a photosensitiser.
15. A method according to any preceding claim, wherein said polymerisable formulation includes a third component which comprises a polymerisable compound.
16. A method according to any preceding claim, wherein said polymerisable formulation is arranged to produce an epoxy or polyurethane polymer.
17. A method according to any preceding claim, wherein the method includes the step of contacting activated polymerisable formulation with a substrate after step (ii), and the method comprises forming a coating of polymerised and/or cured polymerisable formulation on said substrate and/or the polymerisable formulation is arranged to enter an opening in the substrate.
18. Apparatus for forming a polymeric material on a substrate, the method comprising: (a) a flow device arranged to cause a polymerisable formulation to flow in a turbulent and/or tortuous manner; (b) radiation means for subjecting polymerisable formulation in said flow device to actinic radiation.
19. Apparatus according to claim 18, wherein said flow device is a static mixer.
20. Apparatus according to claim 18 or claim 19, wherein said flow device is transparent at least in part to actinic radiation from said radiation means.
21. Apparatus according to any of claims 18 to 20, wherein said radiation means comprises a first array of radiation emitting elements, said array being elongate and extending in the direction of flow of polymerisable formulation through the flow device.
22. Apparatus according to claim 21, wherein said radiation means comprises a second array of radiation emitting elements, said second array being elongate and extending in the direction of flow of polymerisable formulation through the flow device; and said radiation means comprising a third array of radiation emitting elements, said third array being elongate and extending in the direction of flow of polymerisable formulation through the flow device; and said radiation means comprising a fourth array of radiation emitting elements, said fourth array being elongate and extending in the direction of flow of polymerisable formulation through the flow device.Amendment to the claims have been filed as follows Claims 1. A method of forming a polymeric material on a substrate, the method comprising the steps of: (i) causing a polymerisable formulation to flow in a turbulent and/or tortuous manner; and (ii) subjecting the polymerisable formulation to actinic radiation whilst it is flowing in said turbulent and/or tortuous manner.2. A method accordingly to claim 1, which includes providing the polymerisable formulation in a flow path between a first position and a second position, said second position being downstream from said first position and wherein said flow path is arranged to cause the formulation to flow in said turbulent and/or tortuous manner.3. A method according to claim 2, wherein said flow path includes baffles to alter the direction of movement of said fluid moving between said first and second positions.4. A method according to any preceding claim, which includes a static mixer to cause the formulation to flow in said turbulent and/or tortuous manner.5. A method according to any of claims 2 to 4, wherein said flow path has a fluid inlet and a fluid outlet, wherein the distance between the inlet and outlet is less than 1 metre and is at least 5cm.6. A method according to claim 5, wherein the area defined by said fluid inlet into which fluid can pass is at least 0.5cm2 and less than 10cm2.7. A method according to any of claims 2 to 6, wherein a housing which defines the flow path between said first and second positions is transparent, at least in part, to actinic radiation.8. A method according to any preceding claim, which uses a static mixer to cause said polymerisable formulation to flow in a turbulent and/or tortuous manner, wherein said static mixer is transparent to said actinic radiation.9. A method according to any preceding claim, which comprises directing radiation in a first direction towards said polymerisable formulation and directing radiation in a second direction towards said polymerisable formulation, wherein the angle defined between said first and second directions is in the range 10 to 1800.10. A method according to claim 9, the method including directing radiation towards said polymerisable formulation in a third direction which is positioned between said first and second directions, said third direction defining respective angles in the range to 120° to said first direction and to said second direction.II. A method according to any of claims 2 to 10, wherein radiation is directed over a length of at least 1cm and less than 25cm along the direction of the flow path.o 12. A method according to any preceding claim, wherein said actinic radiation is arranged to activate a component of the polymerisable formulation.13. A method according to any preceding claim, wherein said polymerisable formulation includes a first component which is arranged to initiate polymerisation of the polymerisable formulation, wherein said first component is an initiator for cationic or base catalysed polymerisation.14. A method according to any preceding claim, wherein said polymerisable formulation includes a second component which is a photosensitiser.15. A method according to any preceding claim, wherein said polymerisable formulation includes a third component which comprises a polymerisable compound.16. A method according to any preceding claim, wherein said polymerisable formulation is arranged to produce an epoxy or polyurethane polymer.17. A method according to any preceding claim, wherein polymerisation of the polymerisable formulation is initiated in step (ii) but the polymerisation is slow enough to allow the polymerisable formulation to be contacted with a substrate, before the viscosity of the polymerisable formulation becomes too high.18. A method according to any preceding claim, wherein the method includes spraying the activated polymerisable formulation at a substrate or delivering a stream or slug of activated polymerisable formulation at the substrate.19. A method according to claim 18, wherein a gun is used to deliver activated polymerisable formulation to the substrate.20. A method according to any preceding claim, wherein the method includes the step of contacting activated polymerisable formulation with a substrate after step (ii), and the method comprises forming a coating of polymerised and/or cured polymerisable formulation on said substrate and/or the polymerisable formulation is arranged to enter an opening in the substrate. r21. A method according to any preceding claim, wherein said method comprises directing activated polymerisable formulation into an opening in a substrate which comprises a defect in the substrate in need of repair.22. A method according to claim 21, wherein the thickness of the material formed from the activated polymerisable formulation on the substrate is in the range 100pm to 10cm.
23. Apparatus for forming a polymeric material on a substrate, the method comprising: (a) a flow device arranged to cause a polymerisable formulation to flow in a turbulent and/or tortuous manner; (b) radiation means for subjecting polymerisable formulation in said flow device to actinic radiation.
24. Apparatus according to claim 23, wherein said flow device is a static mixer.
25. Apparatus according to claim 23 or claim 24, wherein said flow device is transparent at least in part to actinic radiation from said radiation means.
26. Apparatus according to any of claims 23 to 25, wherein said radiation means comprises a first array of radiation emitting elements, said array being elongate and extending in the direction of flow of polymerisable formulation through the flow device.
27. Apparatus according to claim 26, wherein said radiation means comprises a second array of radiation emitting elements, said second array being elongate and extending in the direction of flow of polymerisable formulation through the flow device; and said radiation means comprising a third array of radiation emitting elements, said third array being elongate and extending in the direction of flow of polymerisable formulation through the flow device; and said radiation means comprising a fourth array of radiation emitting elements, said fourth array being elongate and extending in the direction of flow of polymerisable formulation through the flow device.
28. Apparatus according to any of claims 23 to 27, wherein said apparatus includes one or more receptacles for containing components of the polymerisable formulation which are arranged to deliver polymerisable formulation to the flow device.
29. Apparatus according to any of claims 23 to 28, wherein downstream of the flow device, said apparatus comprises a dispensing device which is arranged to dispense polymerisable formulation (after irradiation) onto a substrate.
30. Apparatus according to claim 29, wherein the dispensing device comprises a user-operable control for opening and/or closing a dispensing orifice of the dispensing device.
31. Apparatus according to any of claims 23 to 30, said apparatus containing a polymerisable formulation.
32. Apparatus according to claim 31, said apparatus including an initiator for cationic or base catalysed polymerisation, a photosensitizer and a polymerisable compound.
33. Apparatus according to any of claims 23 to 32, which contains a polymerisable formulation which is arranged to produce an epoxy or polyurethane polymer. rLU Co