NL8901112A - ADHESIVE COMPOSITION. - Google Patents

Description

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Adhesive composition.

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The invention relates to adhesive compositions and in particular to polymerizable compositions which can adhere strongly to rigid hard body tissues such as teeth and bones. The compositions of this invention can be used as liners to which restorative dental filling compositions can be applied and as primer materials to which adhesives for dental use are applied for mounting, for example, orthodontic braces or crowns. The invention therefore also relates to the use of the present compositions as primer materials in a method of restoring, bonding or altering the position of teeth.

Amalgam and restorative dental filling compositions do not adhere very well to dental surfaces.

When filling a dental cavity, the problem of poor adhesion can be improved by forming undercut cavities so as to improve mechanically holding the filling in place. In the case of enamel surfaces, mechanical clamping on a microscopic scale can be improved by etching the surface with phosphoric acid. However, a true adhesive system would enable the dentist to improve surgical operations. The use of phosphoric acid could be greatly reduced or even completely eliminated in some cases; repair treatments involving dentin removal could be performed with much lesser removal of living tissue; leaks around the edges could be reduced.

It should be borne in mind that an adhesive system is associated with bones and 8901 112. "f · ί * - 2 - teeth that are real materials, that is, such a system is combined with living, dynamic tissue and any adhesive as such, it is often the result of a compromise between conflicting influences, for example, to adhere to the surface of a tooth requires hydrophilic groups, but their presence increases the likelihood that the adhesive will be hydrolytically unstable. number of dental adhesives available, some of which are formulated from organic phosphate esters, therefore it is particularly desirable that the active adhesive component has a low concentration in the adhesive composition and that component should therefore have strong adhesive properties. should have a low viscosity so that it flows out easily about the surface to be attached.

European patent application 0074708 discusses a large number of patent descriptions describing various ethylenically unsaturated phosphorus esters as adhesives. In that patent application, rights are claimed for certain phosphate esters based on an alkyl ester of acrylic acid and long chain methacrylic acid, which are reported to have improved adhesive properties in dental applications.

That patent application mentions that 2-methacryloyloxyethyldihydrogen phosphate is a relatively poor adhesive component and causes blistering in a paint layer.

European patent application 0115948 describes the use of organic pyrophosphate esters as polymerizable adhesive components. European Patent Applications 0058483 and 0132318 describe the use of halophosphoric acid esters as polymerizable monomers in adhesives for use in dentistry; these esters contain at least one ethylenically unsaturated functional group and a chlorine or bromine atom bonded directly to the phosphorus atom.

U.S. Patent 4044044 describes the use of phosphate esters of hydroxy acrylates as components of anaerobic adhesive compositions.

89011127

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These compositions are said to remain liquid as long as they remain in contact with the air while they are said to cure rapidly by air-exclusion polymerization. Those adhesive compositions are useful when materials that become loose from objects are prevented, especially under high pressure.

It has now been found that the adhesive properties associated with polymerizable phosphoric acid esters depend not only on the level of impurities in the particular ester, but (also) on the inclusion of a small amount of a related fine filler.

According to the present invention there is provided a one-component, viscous, light curable liquid adhesive composition comprising (a) 2 to 20 parts by weight of at least one substantially pure phosphate ester of the formula CH2 = C (R1) .CO .0.r2.0P (0) (OH) 2 ^ where R 1 · is a hydrogen atom of 20 or a methyl group and R 2 represents -CH 2 -CH 2 -, -CH 2 -CH (CH 3) - or -CH (CH 3) -CH 2 - and (b) 98 to 80 parts by weight of at least one ethylenically unsaturated monomer copolymerizable with the phosphate ester, and 25 (c) 1 to 9% by weight based on a + b of at least one inorganic filler with a particle size less than 0 , 1 μτη, and an effective amount of a catalyst activated by visible light.

The phosphorus ester component in the present compositions is preferably 2-methacryloyloxypropyl dihydrogen phosphate. The phosphate esters used in the compositions of the present invention can be prepared by reacting, for example, (a) hydroxyalkyl acrylate (or methacrylate) with at least an equimolar amount of phosphorus oxychloride in the presence of a tertiary amine, followed by hydrolysis of any remaining chlorine -phosphorus bonds. The dihydrogen phosphor 89 01 1 12 · / 4 '* - 4 - ester is then purified in a series of washing and extraction steps so that the ester becomes substantially pure, i.e. free from other esters of phosphoric acid, so that the content of such impurities less than 5 wt% and preferably less than 2 wt%.

The adhesive compositions of the present invention contain at least one ethylenically unsaturated monomer which is copolymerizable with the phosphate ester. The most commonly used monomers include those of the (meth) acrylate, vinyl urethane and styrene type and vinyl acetate. Other monomers such as (meth) acrylamides, vinyl ethers, fumarates, maleates, vinyl ketones, vinyl nitriles, vinyl pyridines and vinyl naphthalenes can also be used either alone or in combination, provided the viscosity parameter of the composition is met. The concentration of phosphate ester in the adhesive composition is preferably 5 parts by weight or more, and preferably not more than 15 parts by weight.

Vinyl esters suitable for use in the process of the invention include, for example, vinyl acetate and esters of acrylic acid having the structure CH2 = CH-COOR3, wherein R3 is an alkyl, aryl, alkaryl, aralkyl, or cycloalkyl group. For example, R3 may be an alkyl group of 1 to 20 and preferably 1 to 10 carbon atoms. Specific vinyl esters which may be mentioned include, for example, methyl acrylate, ethyl acrylate, n- and isopropyl acrylates and n-iso and tertiary butyl acrylates.

Other suitable vinyl esters include, for example, esters of the formula CH2 = C (R4) COOR3 wherein R4 represents a methyl group. In the ester of the formula CH2 = C (R4) COOR3, R3 and R4 may be the same or different.

Specific vinyl esters which may be mentioned include, for example, methyl methacrylate, ethyl methacrylate, n- and isopropyl methacrylate, and n-, iso and tertiary butyl methacrylate, vinyl esters such as n-hexyl, cyclohexyl and tetrahydrofurfury acrylates and methacrylates. The monomers must have low toxicity 89 0 1 1 1 2? - 5 -> have. Suitable styrene-type aromatic vinyl compounds include styrene and its derivatives, for example alpha alkyl derivatives of styrene, for example alpha methyl styrene and vinyl toluene.

Suitable vinyl nitriles include, for example, acrylonitriles and derivatives thereof, for example methacrylonitrile.

Other suitable ethylenically unsaturated monomers include vinyl pyrrolidone and hydroxyalkyl acrylates and methacrylates, for example hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate.

Polyfunctional monomers are also suitable as polymerization materials, ie monomers containing two or more vinyl groups. Suitable monomers include, for example, glycol dimethacrylate, diallyl phthalate and triallyl cyanurate.

The ethylenically unsaturated material may comprise at least one ethylenically unsaturated polymer, suitably in combination with at least one ethylenically unsaturated monomer.

The present composition is preferably free from volatile solvents.

Such polymerisable materials are preferably liquid ethylenically unsaturated materials such as vinyl urethanes, for example those described in British Pat. Nos. 1352063, 1465097 and 1498421 and in German Offenlegungsschrift 2419887, or the reaction product of a diol, for example glycol, but in especially a bisphenol with a glycidyl alkacrylate, such as the products described in, for example, U.S. Pat. Nos. 3066112 and 4131729 (reference is made to the contents of these patents for reference).

A reaction product of a glycidyl alkacrylate and a preferred diol has the formula 1.

Preferred vinyl urethanes described in the aforementioned British Pat. 8901 112. "/ 6-6 and German Offenlegungsschrift are the reaction products of a urethane prepolymer and an ester of acrylic acid or methacryl Izmir with a hydroxyalkanol having at least two carbon atoms, the urethane prepolymer being the reaction product of a diisocyanate of the structure OCN-R 2 -NCO and a diol of the structure HO-R 6 -OH, where R 5 is a divalent hydrocarbyl group and R 6 is the balance of a condensation product of an alkylene oxide with an organic compound containing two phenolic or alcoholic groups.

Other suitable vinyl urethanes include the products prepared by reacting alkyl and aryl and preferably alkyl diisocyanates with hydroxyalkyl acrylates and alkacrylates, such as those described in British Pat. Nos. 1401805, 1428672 and 1430303 (of which the content is hereby cited as a reference).

The compositions for use in the dentistry of the present invention are cured by irradiating the composition with visible radiation, preferably with a wavelength in the range from 400 nm to 500 nm. In order to achieve curing of the compositions in that range, the compositions contain a catalyst which is activated by visible light. Such a catalyst preferably contains at least one ketone selected from fluorenone and diketone and at least one organic peroxide.

Ketones suitable for use in the compositions of the present invention also exhibit some degree of photosensitive catalytic activity per se without the presence of organic peroxide. Such action of the ketone is enhanced by the addition of a reducing agent as described in German Offenlegungsschrift 2251048. The present ketones are therefore selected from fluorenone and α-diketones and their derivatives which, when mixed with a similar amount of organic amine capable of reduce that ketone when the latter is excited in the excited state. 89 01 1 1 2.

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Reverses, but in the absence of organic peroxide, catalyzes the curing of an ethylenically unsaturated material. Proof of curing can conveniently be obtained by viewing the change of a mixture of the ethylenically unsaturated material containing the ketoh and organic amine each in an amount of 1% by weight based on ethylenically unsaturated material, using an oscillating rheometer, to samples with a thickness of 2 mm, while the mixture is irradiated with light with a wavelength in the range of 400 to 500 nm. Such a viscosity test can be performed according to the method described in British Standard 5199: 1975, paragraph 6.4, with only provisions being made to allow visible light to fall on the mixture.

Preferably, the ketone has a cure time of less than 15 minutes at a radiation level of 1000 w / m2, measured at 470 nm with a bandwidth ± 8 nm, for example, using a Macam radiometer (Macam 20 Photometries, Limited, Edinburgh, Scotland).

Diketones have the formula 2, wherein the groups A which may be the same or different represent hydrocarbyl or substituted hydrocarbyl groups and wherein the groups A may be further linked by a divalent bond or a divalent hydrocarbyl substituted hydrocarbyl group or in which the groups A together can form a fused aromatic ring system. Preferably groups A are the same.

Groups A can be aliphatic or aromatic.

The term aliphatic includes both cycloaliphatic groups and aliphatic groups bearing aromatic substituents, ie aralkyl groups. Likewise, the term aromatic groups includes groups bearing alkyl substituents, i.e., alkaryl groups. Heterocyclic groups also include the term aromatic groups.

The aromatic group can be a benzenoid aromatic group, for example the phenyl group, or it can be a non-benzenoid cyclic group which shows the characteristics of a benzenoid aromatic group according to the 8901 112.1-8 literature.

The groups A, especially when they are aromatic groups, may carry substituent groups other than hydrocarbyl groups, for example halogen atoms or alkoxy groups. Substituents other than hydrocarbyl can inhibit the polymerization of ethylenically unsaturated materials, and when the α-diketone contains such substituents, it is preferably not present in the photopolymerizable composition at such a concentration that it leads to ....... a significant inhibition of the polymerization of the ethylenically unsaturated material in the compositions.

The groups A may further be linked together by a direct bond or by a divalent group, for example a divalent hydrocarbyl group, ie in addition to the bond via the group of formula 3. The groups A may be further linked such that they form a cyclic ring system. For example, if the groups 20A are aromatic, the α-diketone can have the structure of formula 4 wherein Ph is a phenylene group, Y represents> CH2, or a derivative thereof in which one or both of the hydrogen atoms are replaced by a hydrocarbyl group, and m 0, 1 or 2. Preferably, the group Y is bonded to the aromatic groups at the ortho positions of those groups.

The groups A together can form an fused aromatic ring system.

In general, α-diketones can be excited by radiation in the visible part of the spectrum, ie by light with a wavelength of more than 400 nm, for example in the wavelength range of 400 to 500 nm. For the present invention, the α-diketone should have a low volatility to minimize unpleasant odors and concentration variations. Suitable α-diketones include benzyl in which both groups A are phenyl groups, α-diketones in which both groups A are fused 8901 112. ' yr-9 - are aromatic rings, for example a-naphthyl and β-naphthyl, and α-diketones in which the groups A are alkaryl groups, for example p-tolyl. As an example of a suitable α-diketone in which the groups A are non-benzenoid aromatic groups, mention can be made of furil, for example 2.21-furil, Derivatives of the α-diketones in which the groups A carry non-hydrocarbyl groups, such as for example p.p -dialkoxybenzyl, for example p.p'-dimethoxy-benzyl or p.p'-dihalobenzyl, for example p.p'-10 dichlorobenzyl or p-nitrobenzyl can (also) be included.

Groups A may be joined together by a direct bond or by a divalent hydrocarbyl group to form a cyclic ring-15 system. For example, if the groups A are aliphatic groups, the α-diketone can be camphorquinone.

An example of an α-diketone of the structure of formula 4 is phenanthraquinone in which the aromatic groups are joined by a direct bond at the ortho-20 position to the group of formula 3. Suitable derivatives include 2-bromo, 2-nitro, 4-nitro, 3-chloro, 2,7-dinitro, 1-methyl-7-isopropylphenanthraquinone.

The α-diketone may be acenaphthene quinone in which the groups A together form an fused aromatic ring system.

The ketone may also be fluorenone or a derivative thereof, such as, for example, lower alkyl (C 1-6), halogen, nitro, carboxylic acid derivatives and esters thereof, especially in the 2- and 4-positions.

For example, the ketone may be present in the composition at a concentration in the range of 0.01 to 2% by weight of the polymerizable material in the composition, although concentrations outside this range may also be used if desired. The ketone is suitably present in a concentration of 0.1 to 1% by weight, and more preferably 0.5 to 1% by weight, relative to the ethylenically unsaturated material in the composition. The ketone must be soluble in the polymerizable material and the above concentrations in solution concentration.

The organic peroxides suitable for use in the present compositions include the peroxides of the formula R7 - O - O - R7 wherein the groups R7 which may be the same or different are hydrogen, alkyl, aryl or acyl groups where no more than one of the groups R is hydrogen. The term acyl denotes a group of the formula R8 - CO -10 wherein R8 is an alkyl, aryl, alkyloxy or aryloxy group. The terms alkyl and aryl have the meanings given above in groups A and include substituted alkyl and aryl.

Examples of organic peroxides suitable for use in the compositions of the present invention include diacetyl peroxide, di-benzoyl peroxide, di-tertiary butyl peroxide, dilauroyl peroxide, tertiary butyl perbenzoate, ditertiary butyl cyclohexyl perdioarbonate.

For example, the organic peroxide may be present in the composition in an amount ranging from 0.1 to 10% by weight of the polymerizable material in the composition, although concentrations outside this range may also be used if desired.

The reactivity of a peroxide is often expressed in the temperature at which the peroxide has a half-life of 10 hours, ie half of the oxygen becomes available at that temperature within 10 hours. The peroxides in the present compositions preferably have a temperature at which the half-life of 10 hours is less than 150 ° C, more preferably less than 100 ° C.

The rate at which the composition of the invention cures under the influence of visible light can be increased by including in the composition a reducing agent in a concentration of 0.1 to 10% by weight of the polymerizable material, which reducing agent is capable of reducing the ketone as the latter in a 89 01 112.! * - 11 - excited state is. Suitable reducing agents are described, for example, in German Offenlegungs specification 2251048 and include organic amines, phosphites, sulfinic acids.

Generally, non-basic reducing agents are preferred because they are less likely to react with the phosphate ester. Suitable non-basic reducing agents include aldehydes and organotin compounds of the formula 10 (R9) nSn (OR10) m wherein n and m are integers of 1, 2 or 3 and n + m = 4, R9 an alkyl or alkenyl group having 1 to 18 carbon atoms and R10 represents a radical R9 or R9.co- or a radical of the formula ([R9] 3Sn) 20.

The filler is present in an amount of 1 to 9% by weight of the composition and preferably 4 to 6%.

The filler may consist of any form of silicon dioxide including finely ground crystalline silicon dioxide forms including, for example, sand, but preferably consists of a colloidal form (of silicon dioxide) such as pyrogenic, shaped or precipitated silicon dioxide.

The components can be mixed by stirring the polymerizable material and the filler together.

It may be helpful to first dissolve the catalyst components in the polymerizable material. The polymerizable material may be suitably, but less preferred, diluted with a suitable diluent to improve the dissolution of the catalyst components. When the mixing has taken place, the diluent can be removed if desired, for example by evaporation. Preferably, the present composition is substantially free of solvents, because its presence may adversely affect adhesion and lead to toxicity problems.

Because the photosensitive catalyst makes the polymerizable material and monomer sensitive to light in the visible range of 400 to 500 nm, that portion should be 8901112.

The preparation of the present composition in which the photosensitive catalyst is added and the subsequent handling of the composition, for example container filling, are carried out with substantially complete absence of light in that wavelength range. Most suitably, the preparation can be carried out using light outside that range, for example, under the light of electric sodium vapor discharge lamps.

According to a further embodiment of the present invention, a curing method is provided which comprises irradiating the composition according to the invention with visible radiation with a wavelength between 400 and 500 nm. The process can be carried out at any suitable temperature, provided that the composition 15 does not crystallize and bursts, in which case the temperatures are too low, or unnecessarily volatile, in which case the temperature is too high. Preferably, the process is carried out at ambient temperatures, i.e. between 15 ° C and 40 ° C.

The idea is that a tooth surface will be coated with the present composition which is then cured under a visible light source. Suitably, the composition is cured using a portable light source. However, it is preferred that the tooth surface is first pretreated (prepared) before it is coated in this way? a preferred pretreatment agent is a long chain bisbiguanide, poly-biguanide or a quaternary salt as disclosed in British Patent Application 8810412.

A dental composition according to the invention is preferably packaged in single small containers (eg with a capacity of 10 g) to facilitate handling in dental practice and to reduce the risk of accidental curing by eg stray light.

For cosmetic purposes, such compositions for use in dentistry may have a natural tooth color by dyeing or incorporating a dye 8801112; Thus, the present compositions may contain small amounts of pigments, opalescent agents and the like. The composition may also contain small amounts of other materials such as antioxidants and stabilizers, provided that they do not significantly affect curing.

The invention is illustrated by the following examples:

Example 1.

(a) Preparation of phosphate ester.

Phosphorus oxychloride (127.9 g; 0.83 mol) was mixed with methylene chloride (600 cm2). The mixture was stirred and cooled to 0 ° C. A mixture of hydroxypropyl methacrylate (120 g; 0.83 mol), pyridine (65/8 g - 0.83 mol) and methylene chloride (400 cm3) was added dropwise over 45 minutes to the phosphorus oxychloride mixture while the reaction temperature was the range from 0 to 3®C was maintained. The mixture was then stirred at this temperature range for an additional 2 hours. The reaction mixture was then poured into 1 liter of cold water and the methylene chloride layer was separated and washed twice with water. The methylene chloride solution was then mixed with water and the methylene chloride was removed using a rotary evaporator to leave an aqueous phase and some water-insoluble inorganic material. The aqueous layer was washed twice with methylene chloride and then acidified carefully with stirring (208 ml hydrochloric acid). The aqueous phase was then then extracted with ethyl acetate (1 liter) and the aqueous phase was discarded. The concentration of phosphate ester was then determined and analyzed by acid-base titration methods, showing that the ester contained less than 2 wt% impurities based on 2-methacryloyloxy-propyl dihydrogen phosphate. Triethylene glycol dimethacrylate 35 (TEGDM) was then added to form a 90:10 mixture of TEGDM and phosphate. Then ethyl acetate was removed in a rotary evaporator at 65 ° C and under a 50 mm Hg vacuum.

8901 1U7 ί - 14 - (b) A number of formulations (compositions) were prepared with a filler concentration and a composition as listed in Table 1. To the monomer mixture, the following catalyst components were added: w / w%

Kamierquinone 0.73

Dibutyltin dilaurate 0.49 "Topanol" 0 to 200 ppm calculated on the final composition.

"Aerosil" A130 varying amounts

This addition and subsequent operations with the compositions were performed under the light of a sodium vapor discharge lamp.

Adhesion strength evaluation to samples of the above compositions was performed according to the method described in British Dental Journal 1984, pp. 93 to 95, except that the composite HR-20 material used with the adhesive composition was "Occlusin" (a trademark of Imperial Chemical Industries PLC). The dentin surface was coated with a solution of "Vantocil" (0.1 wt% in water), followed by air-jet drying, before applying the adhesive composition. "Vantocil" is a polybiguanide of the formula -f * (CH2) g-NH.C (: NH) NH-5-n wherein n is 4 to 7. "Vantocil" is a trademark of Imperial Chemical Industries PLC. The samples were cured by irradiating a halogen-incandescent lamp with a tuned reflector and a dichroic filter that eliminates ultraviolet radiation; the intensity was 1000 Wm 2 and the curing time was 30 seconds.

"Topanol" is a trademark of Imperial Chemical Industries PLC and "Topanol" 0 is 2,6-ditertiary butyl-4-35 methylphenol.

"Aerosol" is a trademark of Degussa AG: "Aerosil" A130 is a hydrophilic grade of pyrolitic silica with an average particle size 8901112.

* - 15 - size of 0.02 μια.

Table 1.

% filler Strength of compound (MPa) 0 7.0 5 5 13.0 7.5 11.0 10 7.0

The above results are shown in the accompanying figure.

10 Example 2.

A similar bonding strength (bonding strength) was obtained using an adhesive having the following composition:

Wt% 15 Phosphate Ester (as described 9.48 in Example 1)

Vinyl urethane resin x 15.17 TEGDM 70.16

Camphorquinone 0.71 dibutyltin dilaurate 0.48 "Aerosil" A130 4.00 xrals described in Example 1 of European Patent 59649.

The vinyl urethane resin and the phosphate ester are included in the form of solutions in TEGDM and the amount of TEGDM so incorporated is included in the total TEGDM content.

* 15 20 89 01 112. '

Claims (10)

A single component, visibly curable, liquid adhesive composition comprising (a) 2 to 20 parts by weight of at least one substantially pure phosphate ester of the formula 012 = 0 (1¾1) .CO.O.R2 .OP ( O) (OH) 2 wherein R 1 is a hydrogen atom or 10 methyl group and R 2 represents -CH 2 -CH 2 -, -CH 2 -CH (CH 3) - or -CH (CH 3) -CH 2 - and (b) 98 to 80 parts by weight of at least one ethylenically unsaturated monomer copolymerizable with the phosphate ester, and 15 (c) 1 to 9% by weight of fine particulate inorganic filler and an effective amount of a catalyst activated by visible light. The composition of claim 1 wherein the phosphate ester has the formula CH2 = C (CH3) .CO.O.R2.0P (0) (0H) 2 wherein R2 is an isopropylene group. The composition according to claim 1 or 2, wherein the concentration of the phosphate ester is 5 to 15 parts by weight. 4. A composition according to any one of claims 1 to 3 wherein the ethylenically unsaturated monomer comprises a glycol dimethacrylate. The composition of claim 4 wherein the monomer also includes a vinyl urethane. 6. A composition according to any one of claims 1 to 5, wherein the weight amount of filler present is in the range of 4 to 6%. The composition of any one of claims 1 to 6, wherein the filler is colloidal silicon dioxide. A composition according to any one of claims 1 to 7, wherein the visible light activated catalyst comprises camphorquinone and a reducing agent. The composition of claim 8 wherein the reducing agent is an organotin compound with the 09 01! 12: * - 17 - formula (R9) nSn (OR10) m where n and m are integers with a value of 1, 2 or 3 and n + m = 4, R9 is an alkyl or alkenyl group having 1 to 18 carbon atoms and R10 represents a R9 residue or a R9CO- residue. 10. The composition of claim 8 wherein the reducing agent is an organotin compound of the formula ([R933Sn) wherein R9 represents an alkyl or alkenyl group having 1 to 18 carbon atoms. 15 6901112?