AU468552B2 - Orthopaedic device - Google Patents

Description

48.8 8 5 n72

This invention relates to a fabric article suitable for applying to a body member, which member may be in a human being or an animal, and to an orthopaedic device which is produced from the fabric article and which is capable of immobilising the body member. Hitherto, a body member, by which we mean a part of the body which may be immobilised by means of an externally applied device, for example, the neck, or a limb, for example, an arm, leg or finger, has generally been immobilised by applying to the body member a Plaster-of-Paris bandage which is subsequently dried to form an immobilising orthopaedic device, e.g. a cast. Such bandages are wet and are somewhat messy to apply and suffer from the disadvantages that the resultant casts are heavy, and are thus uncomfortable to wear, and are generally impermea ble to X-rays so that if the body member is to be examined by X-rays the cast must first be removed from the body member. In some cases, when the cast has been removed it may be found that the body member has not healed sufficiently and it may then be necessary to reapply a bandage to the body member and reform a cast. Clearly, this is inconvenient. It has been proposed to overcome the above mentioned disadvantages by using orthopaedic devices, e.g. casts, of a plastics material. The plastics material may be applied to the body member in the form of, for example, a fabric article impregnated with a polynuerisable material, the polymerisable material subsequently being polymerised to form the immobilising orthopaedic device. However, although such fabric arti~cles may not be as wet and messy to apply as Plaster-of-Paris bandages and,

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when formed into an orthopaedic device may be permeable to X-rays, the fabric articles suffer from further disadvantages. Thus, it may be necessary, in order to produce an immobilising device in a reasonable length of time, to polymerise the material with which the article is impregnated by heating the fabric article when in position on the body member. Clearly, this may lead to discomfort, and possibly substantial dincomfort, to the wearer of the fabric article. On the other hand, if the fabric article which is impregnated with polymerisable material contains a polymerisation catalyst which does not require heating in order to effect polymerisation then there is a danger that the fabric article will not be storage stable and in particular may tend to become rigid and thus unusable on storage due to premature poly- merisation of the polymerisable material. It has further been proposed to overcome the latter above-mentioned disadvantages by effecting the polymnerisation of the material on the impregnated fabric article by exposing the article to ultra-violet-radiation. However, the-use of ultraviolet radiation suffers from the further disadvantage;that it is known to be harmful to the human eye and when using ultra- violet radiation it may be necessary to take considerable care to shield the patient and the operator from the radiation during use of the impregnated fabric article in the production of an immobilising orthopaedic device. We now provide a fabric article suitable for application to a body member and from which an immobilising orthopaedio device permeable to X-rays may be produced in which the above mentioned disadvantages are substantially overcome, and in

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particular which is storage stable and which avoids the use of heat and ultra-violet radiation in the production of the ortho- paedic device. The present invention provides a fabric article suitable for applying -to a body member, said fabric article being impreg- nated with at least one curable organic material (as herein defined) and at least one photosensitive catalyst comprising at least one photosensitiser, activatable by visible light (as. herein defined) the photosensitive catalyst being capable of curing the organic material to convert the impregnated fabric article into an immobilising orthopaedic device upon exposure of the fabric article to visible light. By U31ng visible light to effect the cure of the organic material to produce the immobilising orthopaedic device it is in general unnecessary to exerc~.se the same degree of care in shielding the patient and operator from the source of light as is necessary in the case where the organic material is cured by exposure to ultraviolet radiation. Consequently, the use of visible light is more convenient, particularly for the operator. F-urthermore, the orthopaedic devices produced from the impregnated fabric articles of the present invention are generally lightweight, and thus are conveni ent to wear, and are in general permeable to X-rays. The use of visible light sources means that relatively cheap and readily available sources of light may be used com- pared with the case -where ultraviolet radiation is used. By the term "curable organic material"' we mean a material comprising a polymerisable ethylnically unsaturated

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material which is capable of being polymerised or cured to a stiff, rigid material. The fabrio article may be woven or non-woven, for example, it may be knitted, and it may be made from any desired material which is capable of being impregnated by, and which is thus capable of acting as a carrier for, the organic material. The fabric article should not be adversely affected by the organic material. For example, the organic material should not be capable of dissolving the fabric to any significant extent. It is preferred that the fabric artiVole has an open structure, the openings in the structure being of a size such that they are not closed after the fabric is impregnated with the organic material. An open structure aide breathability of the resultant immobilising orthopaedic device. The fabric article may be made, for example, of cotton or rayon, or of a synthetic polymeric material, for example, nylon or poly(ethylene terephthalate). Preferably, the fabric article is made of glass fibre, especially in the form of an open structured woven or knitted material. The fabric article may have any suitable shape such that it may be applied to and support and/or enclose the part of the body member which it is desired to immobilise. -Suitably, the fabric article may be in the form of a bandage, that is, the article may have a length substantially greater than its wtith, and -the bandage may suitably be wound around and thus enclose the body member.

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The fabric article may be impregnated with the curable organic material by contacting the fabric article with a liquid composition containing or consisting essentially of the organic material. The curable organic material may be a liquid or solid material. Where the organic material is itself liquid the fabric article may be contacted with the organic material itself. Alternatively, and especially where the organic material is a solid or a viscous liquid, the fabric article may be con- tacted with a solution of the organic material in a suitable diluent. The pDhotosensitive catalyst, which may be present in the liquid composition before the fabric article is impregnated, is desirably soluble in the organic material. The fabric article, especially where it is in the form of a bandage, may be passed through a bath of the liquid composition containing or consisting essentially of the curable organic material, or the liquid composition may be sprayed on or poured onto the fabric article. Excess organic material may be removed from the fabric article, for example, by allowing the article to drain or by squeezing the article, by passing the article into the nip between a pair of rollers. Alternatively, excess organic material may be removed from the fabric article by passing a blade over the surfaces of the article. The diluenit, is used, may be removed by evaporation. When the fabric article is in the form of a bandage it may be applied to the body member by winding around the member, preferably with overlapping of the bandages. As many layers of fabric as desired may be used. However, we prefer to use, for example, two to four layers as with a greater number

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of layers the orgaic material on the lower layers may take an unacceptably long time to cure. After the fabric article has been applied to the'body member the article may be exposed to a source of visible light having a wavelength which is absorbed by the photosensitiser and which is capable of activating the photosensitiser and thus curing the organic material.* The organic material with which the fabric articl.e is impregnated may thus be cured to form an immobilising orthopaedic device on the body member. By visible light we mean light having a wavelength in the range 4000 Rto 7500 Suitable sources of visible light include for example, sources of blue light, daylight fluorescent tubes and tungsten- halogen lamps. Where a light source emits both ultraviolet radiation and visible light the ultraviolet radiation may, if desired, be filtered out, e.g. by including a suitable filter as part of the casing of the light souirce. Before the impregnated fabric article is applied to the body member the body member may be wrapped in a protective material, e.g. a sleeve or the like, in order to protect the member from the curable organic material. The sleeve or the like, which may, for example, be of polyethylene, polypropylene or cotton, may remain in position on the body member after curing of the organic material has been effected in order to produce the-immobilising orthopaedic device, or it may be removed from the body member after the immobilising orthopaedic device has been produced.

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The amount of organic material Impregnated onto the fabric article should be such that after application to a body member and curing of the organic material has been effected the orthopaedic device thereby produced is sufficiently hard and. rigid to immobilise the body member to the desired extent. Suitable amounts of organic material to be used will readily be determined by means of simple experiment and by reference to the examples at the end of this specification. However, we have found that a suitable amount is between and 60% of curable organic material by weight of the impregnated fabric article, more preferably between 20% and of curable organic material by weight of the impregnated fabric article, although amounts outside these ranges may be used if desired. The proportion of organic material to be used will depend on the thickness of the fabric article and on the .number of layers of fabric article applied to the body member, in general, the gr eater the number of layers the less will be the amount of curable organic material required to produce an orthopaedic device of a given strength. The positioning of the light sources will depend on the particular body member which is to be immobilised. ?or

example, where the body member is an arm or leg the light sources may suitably consist of a plurality of lamps, for example, in the shape of tubes, positioned lengthwise with respect to each other so as to define a cylinder in which the body member may be positioned.

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The time required to produce an immobilising orthopaedic device will depend, inter alia, on the intensity of the visible light used, on the nature of the photosensitive catalyst and on the nature of the curable organic material, on the amount of curable organic material on the fabric article, and on the concentration of photosensitiser in the curable organic material. We have found that with the impregnated fabric articles of the present invention it is possible to produce immobilising orthopaedic devices after 2 to 3 minutes irradiation with visible light, although longer times may be necessary in some circumstances. As the organic material containing the photosensitive

catalyst is sensitive to and is curable on exposure to visible light it may be advantageous, in order to decrease the possibility of premature curing of the material, for the impregnation of the fabric article to. be effected in subdued light. The photosensitive catalyst is desirably chosen such that the fabric article impregnated with a curable organic material and a photosensitive catalyst is stable in the dark such that little if any premature curing of the organic material takes place. In order to shield the impregnated fabric article from visible light it is desirably stored between layers of a film- like material, e.g. polyethylene, and also in containers which arec substantially light-tight. Storage between layers of a

film-like material also assists to decrease-the amount of organic material which may be lost by evaporation. Evaporation

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losses and premature curing may also be decreased by storing the

impregnated fabric article at a temperature below ambient,

e.g. at or near 0 0 C.

The curable organic material may consist of or comprise a polymerisable ethylenically unsaturated material.

For example, the material may consist of or comprise one or

more polymerisable ethylenically unsaturated monomers, e.g. one or more vinyl monomers having ethylenic unsaturation in

a terminal group which are polymerisable to a rigid material. Suitable vinyl monomers include, for example, vinyl esters and aromatic vinyl compounds.

Vinyl esters which may be used include, for example, vinyl acetate and esters of acrylic acid having the structure

CH2 OH COOR, where R is an alkyl, aryl, alkaryl, aralkyl or cycloalkyl group. For example, R may be an alkyl group having from 1 to 20, and preferably 1 to 10 carbon atoms.

Particular vinyl esters which may be mentioned include, for

example, methyl acrylate, ethyl acrylate, and n- and iso- propylacrylates.

Other suitable vinyl esters include, for example, esters of the formula CH2 C(R1 )COOR, where R 1 is methyl.

In the ester of formula OH2 C(R)COOO R, R and R1 may be the same or different. Particular vinyl esters which may be mentioned include, for example, methyl methacrylate, ethyl methacrylate, and n- and isopropylmethacrylate. Suitable aromatic vinyl compounds include, for example styrene and derivatives thereof, e.g. tertiary butyl styrene and o-alkyl derivatives of styrene e.g. G-methyl styrene, and vinyl toluene.

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Other suitable vinyl monomers include hydroxyalkyl acrylates and methacrylates, e.g. hydroxyethyl acrylate, hydroxypropylacrylate, hydroxyethyl methacrylate and hydroxy- propylmethacrylate.

The vinyl monomer may be polyfunctional, that is, it may contain two or more ethylenically unsaturated groups

per molecule. The polyfunctional vinyl monomer may be used alone or in combination with at least one monofunctional vinyl monomer, polymerisation of the monomer or mixture of monomers producing a cross-linked polymeric product. Suitable poly- functional vinyl monomers include divinyl benzene and glycol

dimethacrylate and a vinyl-ended compound prepared by reacting

an isocyanate-ended urethane prepolymer with a vinyl monomer containing an isocyanate-reactive group. It is preferred that the organic material should have a viscosity such that, when impregnated onto the fabric article,

it is not so mobile that it runs off the fabric article, and furthermore, it is preferred that the impregnated fabric article is not so sticky and tacky that it is unpleasant or awkward to use. For these reasons a polymerisable ethylenically unsaturated monomer or mixture of such monomers may not be particularly

suitable. In order to provide an organic material having greater viscosity and which is thus less mobile and which has less tendency to run off the fabric article, the curable organic

material may comprise a mixture, preferably a solution, of at

least one polymeric material and at least one polymerisable

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ethylenically unsaturated monomer. For example, the poly- merisable ethylenically unsaturated monomer may be any of the vinyl monomers hereinbefore referred to and the polymer may be a polymer of any of the polymerisable vinyl monomers hereinbefore referred to. The concentration of the polymer in the monomer may be chosen to give a mixture having the desired viscosity. Suitably, in a mixture comprising polymer and monomer the polymer and monomer may be used in admixture in a proportion of parts by weight in the range polymer:monomer of 10:90 to 80:20, preferably 20:80 to 60:40. For example, the organic material may be a solution of poly(methacrylate) in methyl methacrylate. Preferred organic materials include polymeric materials having a plurality of ethylenically unsaturated groups in ad- mixture with at least one ethylenically unsaturated monomer copolymerisable with the ethylenioally unsaturated groups in the polymeric material. In particular there may be mentioned a mixture of an ethylenically unsaturated polyester and an ethylenically unsaturated monomer. The ethylenically unsaturated monomer may be any of tie vinyl monomers hereinbefore described and the ethylenically unsaturated polyester may be made by condensing an ethylenically unsaturated dicarboxylic acid or anhydride, optionally in ad- mixture with a saturated dicarboxylic acid or anhydride, with a saturated diol, optionally in admixture with an ethylenically unsaturated diol. Small amounts of polycarboxylic acids and/or polyols having a functionality of greater than two may be used if desired.

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Suitable ethylenically unsaturated acids or anhydrides

include, for example, maleic acid and anhydride, fumaric acid

and itaconic acid. Suitable saturated dicarboxylic acids

include isophthalic acid and terephthalic acid. The diol may

be, for example, ethylene glycol, propylene glycol, butylene glycol, di(ethylene glycol), or di(propylene glycol).

The photosensitiser in the photosensitive catalyst should be capable of curing the curable organic material upon

exposure of the impregnated fabric article to visible light.

Suitable photosensitisers activatable by visible light include, for example, uranyl compounds and especially ionisable

uranyl salts. The visible light used to activate the uranyl

compound photosensitiser may suitably be in the range 4000 X to 6000 A.

Suitable uranyl compounds include, for example, uranyl

salts of inorganic acids, e.g. uranyl nitrate, uranyl sulphate,

and uranyl halides, e.g. uranyl chloride and uranyl iodide,

and uranyl 2-ethyl hexyl phosphate; and uranyl salts of organic acids, for example, salts of monobasic or dibasic acids, e.g. salts of fumaric acid, acetic acid, propionic acid, butyric acid, glutaric acid, benzoic acid, oxalic acid and succinic acid. The photosensitive catalyst may comprise a uranyl com- pound as photosensitiser and an activator which leads to an

increase in the rate at which the organic material may be

cured. The activator may be, for example, an alcohol in which the hydroxyl group is not directly attached to an aromatic group, e.g. methanol, ethanol, propanol or butanol; an aldehyde, e.g. acetaldehyde, propionaldehyde or butyraldehyde; or an ether,

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e.g. diethyl ether, dipropyl ether or a cyclic ether, e.g.

ethylene oxide, propylene oxide or tetrahydrofuran.

The photosensitiser may be, for example, manganese

carbonyl and an organic halide, e.g. carbon tetrachloride, carbon tetrabromide, trichloroacetic acid or tribromoacetic

acid or an ester of said acids.

The photosensitiser in the photosensitive catalyst may be a photosensitive dye, e.g. rose bengal, eosein, erythrosin

or phloxin, the visible light which is used having a wavelength which is absorbed by the dye and which activates the dye.

A preferred photosensitiser for use in the photo-

sensitive catalyst is fluorenone or an a-diketone having the structure A- C- C-A II II 0 0

where the groups A, which may be the same or different, are

hydrocarbyl or substituted hydrocarbyl groups. The aforementioned

photosensitisers are preferred on account of the rapid rates of

cure which may be obtained using the said photosensitisers and

on account of their relative insensitivity to the presence of

oxygen. o Light having a wavelength in the range 4000 A to o 5000 A may suitably be used to activate the latter photo- sensitisers.

In the o -diketone having the structure A- C- C A II I! 0 0

the groups A, when hydrocarbyl, may be, for example,

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aliphatic, e.g. alkyl having from 1 to 10 carbon atoms; aromatic, e.g. phenyl; cycloaliphatic, e.g. cyclohexyl;

aralkyl, e.g. benzyl; or alkaryl, e.g. tolyl. Alternatively, the groups A may together form a

divalent radical such that in the photosensitiser the groups A For together with the carbonyl groups form a cyclic structure. example, the groups A may form a divalent aliphatic group, or a they may form an aromatic group, and in particular may form

fused aromatic ring system. For example, the groups A may be methyl in which case

the photosensitiser is biacetyl, phenyl in which case the photo- case the sensitiser is benzil, a-naphthyl or 0 -naphthyl in which or photosensitiser is c-naphthil or 1-naphthil respectively, is alkaryl, e.g. tolyl, in which case the photosensitiser tolil, e.g. p-tolil. Where the groups A form a divalent aliphatic group groups the photosensitiser may be camphorquinone and where the be A form a fused aromatic ring system the photosensitiser may acenaphthene quinone. Where the groups A are substituted hydrocarbyl the

substituent group or groups should not result in substantial

inhibition of the rate of cure of the curable organic.material. the groups A are Examples of suitable photosensitisers in which and substituted hydrocarbyl include p,p'-dimethoxy bensil

p,p'-dihalobenzil, e.g. p,p'-dichlorobenzil. aromatic The groups A, when aromatic, may be benzenoid cyclic group, e.g. phenyl groups, or they may be non-benzenoid groups which are recognised in the art as possessing the

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characteristics of benzenoid aromatic groups. A suitable non-

benzenoid aromatic group A is the group or 0 may be furil. example, the photosensitiser We have found that the rate at which the organic

material may be cured is increased where the photosensitive

catalyst comprises fluorenone or anc -diketone as described together with a reducing agent which is capable of reducing

the hotosensitiser when the photosensitiser is in an activated state. The reducing agent should have a reduction potential

such that it is capable of reducing the photosensitiser when the photosensitiser is in an activated state yet is incapable of reducing the photosensitiser when the latter fs not activated

by the visible light. Furthermore, it is believed the reducing

agent, when oxidised by the activated photosensitiser, should be

capable of initiating cure of the organic material, for example,

it should be capable of initiating polymerisation of the ethy-

lenically unsaturated monomer where the organic material includes

such a monomer. The reducing agent, at the concentration at

which it is present in the curable organic material should have

little or no inhibiting effect on polymerisation. Whether or

not a reducing agent has an inhibiting effect may be determined by means of simple experiment, for example, by effecting cure

of the organic material by means of a thermal initiator in the

presence of, and in the absence of, a reducing agent in the

desired concentration and comparing the rates of cure in the presence and absence of the reducing agent.

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Suitable reducing agents include compounds having the structure R2 R2 where M is an element of Group Vb of the Periodic Table of the Elements and the units R, which may be the same or different, are hydrogen atoms, hydrocarbyl groups, substituted hydrocarbyl groups or groups in which two units R 2

together with the element M form a cyclic ring system, no more than two of the units R2 being hydrogen atoms, and where the element N is attached directly to an aromatic group R2 at least I one .of the groups R 2 has a C group attached to M. H The Periodic Table of the Elements referred to is that published in "Advanced Inorganic Chemistry", second edition, by F A Cotton and G Wilkinson (Interscience 1966).

R2Preferably, the reducing agent having the structure

2 N R2 is free of aromatic groups attached directly to

the element M. The element M in the reducing atent may be, for example, phosphorous or more preferably nitrogen. If desired, N may be arsenic or antimony. The reducing agent may be primary, secondary or tertiary 2 that is, in the structure R2 M R2 two, one or none of the units 12 respectively may be hydrogen atoms. For example, tte reducing agent may be a primary, secondary or tertiary amine or phosphine. One or more of the groups R2 may be hydrocarbyl. The hydrocarbyl group may be, for example, alkyl, cycloalkyl or alkaryl. Suitably, the group R2 may be an alkyl group having from I to 10 carbon atoms.

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Examples of suitable reducing agents in which one or

more of the units R2 is hydrocarbyl include propylamine,

n-butylamine, pentylamine, hexylamine, dimethylamine, diethyl-

amine, dipropylamine, di-n-butylamine, dipentylamine, tri-

methylamine, triethylamine, tripropylamine, tri-n-butylamine,

tripentylamine, dimethylaminoethyl methacrylate, dimethylamino

alcohols, e.g. dimethylamino ethanol, and dimethylamino propanol,

and long chain fatty amines, e.g. C1 8 H3 7 NMe 2 Examples of

reducing agents containing aromatic groups include N,N'-dimethyl aniline and N-methyl diphenylamine. It is to be understood that where we refer to specific

examples of suitable reducing agents in which the element M is

nitrogen we also wish to include corresponding specific examples in which the element M is phosphorous, arsenic or antimony.

One or more of the units R2 may be substituted hydro-

carbyl group and in particular the hydrocarbyl group may carry a substituent having the structure R1 M where M

is an element of Group Vb of the Periodic Table of4the Elements and the unit R3 is, for example, an alkylene chain and the units R4, which may be the same or different, are for example, hydrogen atoms or hydrocarbyl groups. Examples of reducing agents having the structure R2 R2 R2 in which at least one of the units R2 is a substituted

hydrocarbyl group include diamines of the structure R4 N (CH 2 N-R4 in which n is a whole number of at R nR least two and the groups R4 which may be the same or different,

are hydrogen atoms or hydrocarbyl, especially alkyl groups. For

example, the reducing agent may be ethylene diamine, trimethylene

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diamine, tetramethylene diamine, pentamethylene diamine or

hexamethylene diamine, or N-hydrocarbyl, especially N-alkyl

derivatives thereof. Other suitable reducing agents include R4 R derivatives having the structure N (CH2)n N 4 R in which one or more of the hydrogen atoms in the -CH unit 4 2 R are substituted by an N- group, especially an -NH2 group.

Examples of reducing agents in which the element M forms no part of a cyclic ring system include piperidine, and N-hydrocarbyl, especially N-alkyl, derivatives of piperidine.

Other reducing agents include triallylamine, (allyl) 2 -N-CH 2 -CH 2 -N-(allyl)2 allyl thiourea, o-tolyl thiourea, soluble salts of aromatic sulphinic acids, e.g. S-benzyl iso-thiuronium p-toluene sulphinate, and sodium

diethyl dithiophosphate.

One or more of the aforementioned reducing agents may be used in combination with one or more of the aforementioned

uranyl compound photosensitisers or with one or more of the aforementioned photosensitive dyes in order to accelerate the

rate at which the uranyl compound or photosensitive dye is able to effect cure of the organic material on irradiation with

visible light.

Suitably, the concentration of the photosensitiser in the photosensitive catalyst is in the range 0.01% to 5% or even

by weight of the curable organic material and, where the catalyst

contains a reducing agent, the concentration of the reducing

agent is suitably in the range 1% to 5% by weight of the curable

organic material, although concentrations of photosensitiser and reducing agent outside these ranges may be used if desired.

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catalyst comprises Similarly, where the photosensitive which is an alcohol in which a ixranyl compound and an activator directly to an aromatic group, the hydroxyl group is not attached may suitably be used in a an aldehyde or an ether, the activator of' the curable organic concentration of 1% to 5% by weight m.,aterial. which the fabric The curable organic material with provided that article is impregnated may contain a pigment light to an excessive the pigment does not absorb visible the photosensitiser in the extent at the wavelength at which light and is thus activated. photosensitive catalyst absorbs be transparent to visible light Preferably, the pigment should is activated. at the wavelength at which the photosensitiser In.e pigmLent may be white, and may be, for examnple T1O 2 orthopaedic device will in which case the resultant immobilising pigments may be used. For be white., Alternatively coloured benzil is used as the photo- example, we have found that where catalyst it is possible to use sensitiser in the photosensfitive green or blue colour to th e pigments which give a red, yellow, immobilising orthopaedic device. concentration of up. Suitably, pigments are used in a organic material, and preferably to 3% by weight of the curable by weight of the curable in a concentration of 1%or less organic material. which the fabric The curable organic material with a filler, for example, article is impregnated may contain may serve to make the impreg- calcium carbonate or kaolin which and thus more convenient to nated fabric article less sticky handle. 9 A 468.552

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Although the fabric article of the present invention which is impregnated with a curable organic material is intended

for use in the production of an imnobilising orthopaedic device it is to be understood that the article may be used in applications

other than orthopaedic applications. The invention is now illustrated by the following

Examples in which all parts are expressed as parts by weight.

Example 1 A photosensitive catalyst of 1.25 parts of benzil and parts of dimethylaminoethyl methacrylate was dissolved in

parts of acetone and charged to a solution of 38.7 parts of

an ethvlenically unsaturated polyeter and 23-7 part~a nf m~r-

The polyester was a condensation product of propylene glycol,

fumnaric acid and isophthalic acid (funiaric acid:isophthalic

acid molar proportion the product having a hydroxyl value of 40.3 mg KOH g- and an acid value of 4.5 mg. KOH g A 2 in. wide cotton bandage was impregnated by immersing

the bandage in the solution for 2 minutes and the bandage was then removed and the excess solution allowed to drain off. The solution formed 76% by weight of the impregnated bandage. The bandage was then wound onto a cylindrical mandrel with over- lapping of the bandage. The mandrel had a diameter of 1.7 in. A 6 in. length of a mandrel was covered by the bandage the

thickness of the bandage varying between 3 and 4 layers. The bandage was then irradiated for 3 minutes with a

light source comprising eight 20 watt blue light fluorescent 0 tubes having a maximum emission at 4300 A and emitting ultra-

violet radiation and visible light, (Thorn Lighting Limited)

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each tube having dimensions 2 ft. long by 1.5 in. diameter,

the tubes being arranged lengthwise with respect to each other

so as to define a cylinder having a diameter of 6 in. The

bandage on the mandrel was inserted into the cylinder defined

by the lamps. After irradiation the resultant cast was removed

from the mandrel by sliding it off the mandrel. The impregnated bandage was found to have cured to a

rigid, non-tacky cast.

Exam-n e 2 The procedure of Example I was followed except that

the photosensitive catalyst which was used comprised 0.4 part of uranyl nitrate hexahydrate (in place of the benzil) and 0.8

part of dimethylaminoethyl methacrylate dissolved in 10 parts

of acetone and a solution of 12.4 parts of unsaturated polyester

in 7.6 parts of styrene was used. In place of the cotton

bandage the bandage used was a 2 in. wide woven glass fibre

bandage (New Tean Hall Mills). The solution formed 28% by

weight of the impregnated bandage. The impregnated bandage was wound onto the mandrel

to form a double thickness and the bandage was irradiated for

eight minutes. After removal from the light source as used in

Example 1 the impregnated bandage was found to have cured to a rigid non-tacky cast.

Example 3

An impregnated bandage was produced following the procedure of Example I except that the photosensitive catalyst

comprised 0.6 part of benzil and 1.2 parts of dimethylaminoethyl

methacrylate dissolved in 10 parts acetone. The catalyst was

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added to a solution of 20.3 parts of unsaturated polyester and

12.4 parts of styrene and the bandage used was 7 in. wide warp knitted bandage of poly-(ethylene terephthalate). The solution

formed 54% by weight of the impregnated bandage. The impregnated bandage was wound on a mandrel following

the procedure of Example 2 and irradiated for 5 minutes. After

removal from the light source as used in Example I the bandage was found to have cured to a rigid non-tacky cast. Example 4 An impregnated bandage was produced following the

procedure of Example 1 except that the photosensitive catalyst

comprised 0.4 part of benzil and 0.8 part of dimethylaminoethyl

methacrylate dissolved in 15 parts of acetone. The catalyst

was added to a solution of 15 parts of unsaturated polyester

and 5 parts of vinyl toluene (in place of the styrene of

Example and the bandage used was a: 2 in. wide weft knitted

bandage of poly(ethylene terephthalate). The solution formed

47% by weight of the impregnated bandage. The impregnated bandage was wound on a mandrel following

the procedure of Example 2 and the bandage was irradiated for

minutes. After removal from the light source as used in

Example I the bandage was found to have cured to a hardened, rigid, non-tacky cast which became more rigid over a period of 30 minutes.

REample The procedure of Example 4 was followed except the

bandage used was a 2 in. wide weft knitted glass fibre bandage

(BDS Industrial Fabrics). The solution formed 37% by weight

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of the impregnated bandage, and the bandage on the mandrel was irradiated for 3 minutes. After removal from the light source as used in -apnule 1 the bandage was found to have cured to a ha-rdene6, rigid, non-tacky cast which became more rigid over a period of 30 minutes. Example 6 An impregnated bandage was produced following the procedure of Ebample I except that a photosensitive catalyst of 0.26 part of benzil and 0.52 part of dimethylaminoethyl methacrylate dissolved in 10 parts of acetone was used. The catalyst was added to a solution of 10 parts of unsaturated polyester and 3.3 parts of vinyl toluene (in place of the styrene of Example 1) and the bandage used was a 2 in. wide woven glass fibre bandage as used in Example 2. The solution formed 25% by weight of the impregnated bandage. The impregnated bandage was wound on to a mandrel following the procedure of Example 2 and the bandage was irradiated with the light source as used in Example I for three minutes to produce a rigid non-tacky cast. Example 7 An impregnated bandage was produced following the procedure of EIxample 1 except that a photosensitive catalyst of 0.2 part of benzil and 0.5 part of N,N,N ,N ,-tetramethyl ethylene diamine dissolved in 10.5 parts of acetone was used. The catalyst was added to a solution of 10.5 parts of unsaturated polyester and 7 parts of vinyl toluene (in place of the styrene of Example and the bandage used was a 2 in. wide woven glass fibre bandage as used in Example 2. The solution formed

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22% by weig)t of the impremated bandage. The impregnated bandage was wound on a mandrel following the procedure of UBxample 2 and the bandage was irradiated for 3 minutes with the light source as used in Example 1 to produce a rigid non-tacky cast. Example 8 An impregnated bandage was produced following the procedure of Example I except that a photosensitive catalyst of 0.2 part of benzil and 0.4 part of 2 -dimethylaminopropan- 2-ol dissolved in 10 parts of acetone was used. The catalyst was added to a solution of 10 parts of unsaturated polyester and 3.3 parts of vinyl toluene (in place of the styrene of Example and the bandage used was a woven glass fibre bandage as used in Example 2. The solution formed 26% by weight of the impregnated bandage. The impregnated bandage was wound on a mandrel following the procedure of Example 2 and the bandage was irradiated for three minutes with the light source as used in Example I to produce a rigid non-tacky cast. Example 9 An impregnated bandage was produced following the procedure of Example 1 except that a photosensitive catalyst of 0.2 part of benzil and 0.4 part of dimethyl aminoethyl methacrylate dissolved in 10 parts of acetone was used. The catalyst was added to a solution of 10 parts of unsaturated polyester, 3.3 parts of divinyl benzene and 2.6 parts of ethyl styrene (in place of the styrene used in Example 1) and the bandage used was a woven glass fibre bandage as used in Example 2.

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48 85n2

The solution formed 22% by weight of the impregnated bandage. The impregnated bandage was wound on a mandrel following the procedure of Example 2 and the bandage was irradiated for 15 minutes with a light source as used in Example 1 to produce a rigid non-tacky cast. xamiple

The procedure of Example 9 was followed except that the divinyl benzene and the ethyl styrene were replaced by 3.3 parts of p-tertiary butyl styrene. The solution formed 22% by weight of the impregnated bandage and the bandage was irradiated with a light source as used In Example 1 for 3 minutes to produce a rigid non-tacky cast. Example 11 The procedure of Example 9 was followed except that the divinyl benzene and ethyl styrene were replaced by 1.65 parts of methyl methacrylate and 1.65 parts of styrene. The solution formed 15% by weight 'of the impregnated bandage and the bandage was irradiated for 3 minutes with a light source as used in Example I to produce a rigid non-tacky cast. Example 12 An impregnated bandage was produced following the procedure of Example 1 except that a photosenditive catalyst of 0.4 part of benzil and 0.8 part of dimetbylaminoethyl meth- acrylate was used and 20 parts of a vinyl urethane was used in place of the unsaturated polyester and styrene. The bandage used was a woven glass fibre bandage as used in Example 2. The vinyl urethane formed 25% by weight of the impregnated bandage. The vinyl urethane was produced by reacting,

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48 8 8 5 n72

in a molar proportion of 2:1, 4:4'-diphenylmethane diisocyanate

and an oxypropylated bisphenol-A having the structure: CH H 0 CH CH 4n0 0 4 CH CH 0 4 H

1 R2 3 1 2 in which n and m are on average one, and one of R I and R2 is H and the other is CH3 and thereafter reacting, in a molar proportion of 2:1; the resultant isocyanate-ended product with 2-hydroxyethyl methacrylate.

The impregnated bandage was wound on a mandrel following the procedure of Example 2 and the bandage was irradiated for

minutes with the light source as used in Example 1 to produce a rigid non-tacky cast.

Example 13

An impregnated bandage was produced following the procedure of Example 9 except that the benzil was replaced by

fluorenone and the divinyl benzene and ethyl styrene were re-

placed by 2.5 parts of vinyl toluene. The solution formed 19% by weight of the bandage and the bandage was irradiated

for 5 minutes with the light sources as used in Example 1 to produce a rigid non-tacky cast. Example 14 A solution was made up comprising 25 parts of poly- (methyl methacrylate )(Diakon MO-900 Imperial Chemical Industries Limited), 75 parts of methyl methaorylate, 2 parts of bensil and 4 parts of dimethylaminoethyl methaorylate. A 2 in. wide woven glass fibre bandage as used in Example 2 was passed through the

solution, the bandage was removed, and the excess solution was

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allowed to drain off. The solution formed 24% by weight of the

impregnated bandage. The bandage was wound onto a cylindrical mandrel over- having a diameter of Ij in. The layers of bandage were between lapped to form two layers and the mandrel was placed each bank two banks of daylight tubes (Thorn Lighting Ltd.), being placed comprising 13 daylight tubes the banks of tubes of 5800 1 and in. apart. The tubes had a maximum emission region of the emitted 98% of the radiation in the visible the resultant cast spectrum. After irradiating for 30 minutes the mandrel. was removed from the mandrel by sliding it off non-tacky cast. The bandage was found to have cured to a rigid Example that The .procedure of Example 1 was followed except and 12.5 parts of 31 parts of polyester, 19 parts of styrene and dimethyl- acetone were used, and in place of the benzil 1 there was used 1 part aninoethyl methacrylate used in Example of dimethylamino of uranyi nitrate hexahydrate and 2 parts as used in &zample I ethanol. In place of the cotton bandage in Example 2. The there was used a glass fibre bandage as used 31.5% by weight of the solution of polyester and styrene formed impregnated bandage. irradiated The bandage was wound onto a mandrel and produce a rigid non- following the procedure of Example 14 to tacky cast.

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48 sssm,

Example 16 The procedure of Example 15 was followed except that in place of the uranyl nitrate hexahydrate and dimethylamino- ethanol there was used 0.125 part of fluorenone and 2 parts of dimethylamino propanol. The solution of polyester and styrene formed 33.5% by weight of the impregnated bandage. After irradiation for 10 minutes a rigid non-tacky cast was produced. Example 17 In order to demonstrate that the impregnated bandage may include a pigment a solution of 57.2 parts of the polyester as used in Example 1, 28.3 parts of vinyl toluene, 28.5 parts of acetone, 2 parts of benzil and 4 parts of dimethylamino- ethanol was made up and 0.85 part of T1O 2 was added to the solution. A glass fibre bandage as used in Example 2 was impregnated with the resultant mixture. The bandage was allowed to drain for 5 minutes. The solution of polyester and vinyl toluene formed 40% by weight of the impregnated bandage., The bandage was wound onto a mandrel following the procedure of Example 14 and the bandage was irradiated with three 400 watt Tungsten-halogen lamps (Thorn Lighting Ltd.). The lamps emitted mainly visible light with a peak intensity at 4150 2 with a small amount of ultraviolet radiation. After irradiation for three minutes a white, rigid, non-tacky cast was produced. By way of comparison and in order to illustrate the effect of irradiation with ultraviolet radiation the above procedure was followed except that bandage on the mandrel

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48 885 n2

was irradiated by 16 2 ft. long 20 watt Blacklight-Blue tubes

(maxinum emission at 3500 R) arranged to form a cylinder 8 in.

in diameter. After irradiating for 20 minutes the bandage on the mandrel was found to be soft and sticky and when removed from

the mandrel the 3ayers of bandage unwound. A rigid cast was

not formed. Example 18 The procedure of Example 1 was followed except that .62 parts of polyester, 38 parts of styrene, 2 parts of benzil

and, in place of the-dimethylaminoethyl methacrylate, 4 parts of dimethylaminoethanol were used. In place of the cotton bandage of Example I a glass fibre bandage as used in Example 2 was used. The bandage wound on the mandrel was irradiated by one 400 watt tungsten-halogen lamp as used in Example 17. The lamp was placed 3 ft. from a parabolic reflector and the bandage on the mandrel was placed at the focal point of the

reflector. After irradiating for 2 minutes, a rigid non-tacky

cast was produced. By way of comparison and in order to illustrate the effect of using visible light with an ultraviolet sensitive photosensitiser the above procedure was repeated except that

the benzil and dimethylaminoethanol were replaced by 2 parts of

benzoin.

After irradiation for 20 minutes the bandage on the mandrel was soft and tacky and could be unwound. A rigid cast

was not produced.

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48.88572

Example 19 In order to illustrate the use of various pigments the procedure of Example 1 was followed except that 62 parts of polyester, 38 parts of styrene, 2 parts of benzil and 4 parts of dimethylaminoethyl methacrylate were used. In separate experiments 0.3 part of a number of different pigments were included in the mixtures of polyester and styrene. A bandage as used in Example 2 was used. The impregnated bandages comprised 60% by weight of the solution of polyester and styrene. The following results were obtained.

Pigment Irradiation Time Comment Red pigment 3 minutes Rigid ast (Crystic Red 5000) Blue piment 5 minutes Rigid Cast (Crystic Blue 107) Yellow pigment 5 minutes Rigid Cast (Crystic Yellow 3060) Green pigment 3 minutes Rigid Cast (mixture of Crystic Blue 107 -and Crystic Yellow 3060) (Crystic is a Registered Trade Mark, Scott Bader and Co. Ltd.)

Example The procedure of Example 8 was followed in three separate experiments except that in place of the benzil there was used 0.2 part of cx-naphthil, 0.2 part of p-tolil and 0.2 part of camphorquinone respectively. After irradiation with a light source as used in Example 1 rigid non-tacky casts were produced after irradiation for, respectively, 10 minutes, 3 minutes and 3 minutes.

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Example 21

The procedure of Example 17 was followed to make a glass fibre impregnated bandage except that 76.5 parts of

the polyester, 37.8 parts of vinyl toluene, 1.7 parts of

benzil, 3.4 parts of dimethylamino ethanol and 2.5 parts of

Ti02 were used. The solution of polyester and vinyl toluene

formed 40% by weight of the impregnated bandage. A polypropylene stockinette was applied to the wrist

of a test subject and the impregnated bandage was wound around the waist over the stockinette. The bandage was then irradiated for 4 minutes following

the procedure of Example 17 to produce a non-tacky cast which

supported and immobilised the wrist of the test subject.

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THE CLAIMS DEFIVING THE 1NVIANTION ARE AS FOLLOWS:-

1. A fabric article suitable for applying to a body member, said fabric article being impregnated with at least one curable organic material (as herein defined) and at least

one photosensitive catalyst comprising at least one photo- sensitiser activatable by visible light (as herein defined), the photosensitive catalyst being capable of curing the organic

material to convert the impregnated fabric article into an immobilising orthopaedic device upon exposure of the impregnated

fabric article to visible light. 2. A fabric article as claimed in claim 1 whioh is in the form of a bandage and which has an open structure. 3. A fabric article as claimed in claim I or claim 2 in

which the article is a glass fibre article. 4. A fabric article as claimed in any one of claims I to 3 in which the curable organic material comprises at least one

polymerisable ethylenically unsaturated monomer.

A fabric article as claimed in claim 4 in which the curable organic material comprises a mixture of at least one ethylenically unsaturated monomer copolymerisable with the

polyester. 6. A fabric article as claimed in any one of claiis I to in which the article comprises from 10% to 60% of curable organic

material by weight of the impregnated article. 7. A fabric article as claimed in any one of claims I to 6 in which the photosensitive catalyst comprises at least one

uranyl compound as photosensitiser.

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8. A fabric article as claimed in any one of claims 1 to 6

in which the photosensitive catalyst comprises at least one

c-diketone photosensitiser having the structure A- -0 A II 1 0 0

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Claims (1)

1. 48 8 8 5 n2 in which the groups A, which may be the same or different, are hydrocarbyl groups or substituted hydrocarbyl groups.

   9. A fabric article as claimed in claim 8 in which the photo- sensitive catalyst comprises at least one of bcnzil, camphor- quinone, n-naphthil or p-tolil as photosensitiser.

   A fabric article as claimed in any one of claims 1 to 6

   in which the photosensi-tive catalyst comprises fluorenone

   as photosensitiser.

   11. A fabric article as claimed in any one of claims 8 to

   in which the photosensitive catalyst includes at least one

   reducing agent capable of reducing the photosensitiser when

   the photosensitiser is in an activated state.

   12. A fabric article as claimed in claim 11 in which the

   reducing agent is a compound having the structure R 2 M2- R2 where M is an element of Group Vb of the Periodic Table of

   the Elements and the units R 2 which may be the same or different,

   are hydrogen atoms, hydrocarbyl groups, substituted hydrocarbyl

   groups or groups in which two units R 2 together with the

   element M form a cyclic ring system, no more than two of the

   units R 2 being hydrogen atoms, and where the element M is attached directly to an aromatic group R 2 at least one of

   the groups R2 has a C group attached to M. h 13. A fabric article as claimed in claim 12 in which the ?2 compound having the structure R 2 M R2 is a primary,

   secondary or tertiary amine.

   14. A fabric article as claimed in claim 13 in which the amine

   is at least one of dimethylaminoethyl methacrylate, dimethyl-

   amino ethanol and dimethylamino propanol.

   A fabric article as claimed in any one of claims 1 to 14

   in which the photosensitiser is present in a concentration of

   0.01% to 5% by weight of the curable organic materiali.4 85 5 2

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   1 16. A fabric article as claimed in any one of claimas a pigment to 15 in which the curable organic material includes to an provided that the pigment does not absorb visible light excessive extent. 17. A fabric article as claimed in claim 1 substantially 1 to 21. as hereinbefore described and as shown in Rxaiuples

   DATED: 14th November, 1972

   PHILLIPS ORMONDE AND FITZPATRICK, Attorneys for: IT"PERIAL CHEMICAL INDUSTRIES LIMITED. David B. Fitzpatrick

   46 8.55 2