JPH0241521B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to compositions in which a solid phase is dispersed in a liquid phase. When making a dispersion of a siliceous solid material, such as finely divided silica, in an organic liquid, such solid particles tend to stick together, and the dispersion becomes viscous or gels, forming a solidified mass at very low solids concentrations. You may even get used to it. For example, untreated silica with a surface area of 200 m ² /g will form a sludge with methyl methacrylate at about 5% and may become unable to pour or flow at concentrations as low as 8%. Methods of pre-treating the surface of silica are known and treated silica particles are commercially available which allow higher concentrations of silica to be dispersed before the dispersion solidifies. Here we show that it is not necessary to pre-treat the silica and that by adding a combination of additives, superior liquid dispersions can be produced containing higher concentrations of solid siliceous material than previously possible. I found out what I can do. For many applications of solid/liquid compositions, it is desirable for the two-phase composition to have the maximum possible amount of solid phase properly dispersed therein, yet retain some fluidity. . According to the invention: (a) a particulate siliceous material whose longest dimension is 10 μm or less; (b) a liquid or liquefiable polymerizable organic medium (as defined below); (c) a phosphorus oxy of the general formula: acid and (Here R ₁ is a hydrocarbon group having at least 6 carbon atoms or preferably 200 or more
An organic group containing a terminal chain that is any polyether with a molecular weight of 500 to 10,000, where _R2 does not contain an organic group defined as _R1 , a hydrogen atom, or a terminal chain of 6 or more carbon atoms. (either a hydrocarbon or a substituted hydrocarbon group), an organic basic nitrogen compound of the following general formula: (where Z ₁ is the organic group defined as R ₁ above, Z ₂ and Z ₃ may be the same or different, and are defined as R ₂ above); Dispersants comprising mixtures of compounds; Compositions comprising each of components (a) to (c) intimately mixed together are provided. The particulate siliceous material is, for example, a silicate (eg, aluminum silicate, calcium silicate) or a silicate-containing material in finely divided form (eg, talc), but is preferably silica itself. The granular silica may be any form of silica, such as a powder of crystalline silica (e.g. sand), but preferably a pyrogenic or fumed silica having submicron sized particles. It is a colloid. The silica commonly used is high purity untreated silica powder, but it may also be surface treated, for example silane treated silica becomes more hydrophobic than normal. The particle size of a siliceous material is the maximum size (deromendion)
It is preferably less than 1 μm and generally
Silicas with a surface area of 50 to 300 m ² /g are highly suitable for the compositions of the invention. Each of the compounds constituting the dispersant contains a chain group, so that they are amphoteric compounds containing chains that can be solvated by the liquid or liquefiable organic medium component (b) of the composition of the invention. preferable. "Solvable" means that if the chain group is an independent molecule, the liquid medium is significantly better than the theta solvent for the chain independent molecule. It is something. Types of theta solvents are described in The Polymer Handbook (edited by Brandlap and Inmargut, Interscience, 1966) and Principles of Polymer Chemistry (Chapters 12-14, Florey: Cowell, 1953). Are listed. Alternatively, the liquid medium can be defined as being a good solvent for the linear groups of the dispersant, provided that one or both are selected to meet this preferred condition. If one type is known (e.g. usually the organic medium is known;
The reason for this is that the medium contributes significantly to the usefulness of the composition), the other can be selected to match the medium by this solubility criterion. Moreover, the dispersant consists of special chemical groups, namely compounds containing phosphorus oxyacid groups and compounds containing amino groups, and these groups interact or cooperate to greatly improve and enhance the dispersion effect. , and this effect is much more pronounced than that observed when either of these groups is used alone. The organic liquid or liquefiable polymerizable organic medium should not contain acidic or basic groups (e.g. COO ^- NH ₂ ⁺ ) and preferably contain liquid monomers containing vinyl groups, epoxy groups or other polymerizable groups. mass,
or a liquid containing a functional group reactive with a condensation catalyst or promoter. For example, as liquids containing functional groups, liquids containing hydroxyl groups, especially diols and polyols, are preferred, such as polyhydric alcohols which are conventionally used to react with isocyanates to produce polyurethanes or vinylurethanes. For example UK Patent No. 1352063,
1465097, 1498421 specification, German publication 2419887
There are some listed in the issue. Also reaction products of diols, particularly bisphenol compounds, and glycidyl alkacrylates, such as U.S. Pat. No. 3,066,112 and
Those described in No. 4131729 can also be used. A preferred reaction product of a glycidyl alkacrylate and a diol has the general formula: The preferred vinyl urethanes described in the above-mentioned British patent and West German publication are the reaction products of urethane prepolymers and acrylic or methacrylic acid esters with hydroxyalkanols of at least 2 carbon atoms, the urethane prepolymers is the general formula OCH―R ¹ ―NCO
is a reaction product of a diisocyanate with a diol of the general formula HO-R ² -OH (R ¹ is a divalent hydrocarbon group, R ² is an organic compound containing an alkylene oxide and two phenol or alcohol groups). is the residue of a condensate of compounds). Preferably used among the polymerizable liquids are readily available monomers such as hydrocarbons, ethers, esters and amides;
Examples include styrene, vinyl ethyl ether,
Vinyl acetate, methyl methacrylate, ethyl acrylate, butyl methacrylate, ethyl cyanoacrylate, divinylbenzene, glycol dimethacrylate, styrene oxide, tetrahydrofuran,
There are caprolactan and caprolactone. The liquid medium is preferably an inert liquid that is stable at around room temperature, since the required dispersion of the siliceous particles can be more easily achieved if no heating is required for liquefaction of the medium. It is. However, compounds that are solid or semi-solid near room temperature can be used, and the composition is usually made at a temperature above the softening or melting point of the medium. Such temperature should suitably be below 250°C, preferably below 150°C. Phosphorous oxyacid compounds containing groups R ₁ and R ₂ are
Preferably, it is a compound that can be easily produced by a simple chemical reaction, and commercially available compounds are convenient. The group R ₁ is therefore preferably either a hydrocarbon group, in particular a long-chain alkyl group containing from 8 to 22 carbon atoms, or a polyether or polyester chain. From the viewpoint of availability, it is preferable to select from hydrocarbons, such as normal or branched alkyl groups such as octyl, decyl, dodecyl, hexadecyl and octadecyl; alkylbenzenes; groups; polyether groups such as polyoxyethylene chains, polyoxypropylene chains, polytetramethylene oxide chains or copolymer chains thereof; and polyester chains such as polycaprolactone;
There is. Preferably, the group R ₂ is hydrogen, methyl, ethyl, phenyl, benzyl group or the same group as R ₁ . Particularly preferred compounds include the following. Di-(2-ethylhexyl) phosphoric acid, n-hexadecyl phosphoric acid, mono-(methoxypolypropyleneoxy) phosphoric acid, di-(methoxypolypropyleneoxy) phosphoric acid. The basic nitrogen compound has an alkyl group as Z ₁ group,
In particular, compounds containing a _C8 - _C22 alkyl group, or a polyethyleneoxy or polypropyleneoxy group are preferred. The radicals Z ₂ and/or Z ₃ are preferably either of the same type as those preferred as radicals Z ₁ or are hydrogen, lower alkyl (especially methyl and ethyl) phenyl or benzyl groups. Particularly preferred examples of amines are long chain amines, such as commercially available products such as (trademark),
"Ethomeen,""Armeen," and "Synprolam," such as "Synprolam 35" and "Synprolam 35×15." The concentration of the dispersant to be used in the composition of the present invention is not very important, but as a rough guide, it is necessary to select it primarily in relation to the weight of the siliceous particles present in the composition. . It was discovered that a remarkable effect can be obtained from the amount of dispersant used at 0.1% by weight, but no further improvement is generally obtained when the amount exceeds 40% by weight (weight% is based on the weight of the silicon particles). ). For best results it is preferred to use 1-10% by weight of dispersant. The molar ratio of acid and base in the dispersant is from 0.5:1 to
100:1, but preferably about a 50 mole % excess of acid is present, so acid:base molar ratios of 1:1 to 3:1 are preferred. The main purpose of the composition of the invention is to have a high solids content.
The purpose of the present invention is to provide a liquid dispersion. The dispersants in the compositions of this invention significantly reduce the tendency of the siliceous solid materials to gel or stick together and solidify into a solid that cannot be liquefied again. Such tendencies are minimized and large quantities (e.g. 30 to
Solids can be dispersed in the liquid in amounts up to 40 wt% and sometimes even higher, such as up to 90 wt%. Although the resulting composition is still flowable, the absence of such a dispersant or even one component of a dispersant (acid or base) results in solid lumps. Therefore, to obtain the advantages of the present invention, the compositions suitably contain at least 5% by weight of solid material, preferably from 20 to 50% by weight. The primary application of the compositions of the invention is in the use of liquids that polymerize or react to form polymers. Molded or cast articles, such as sheets, films, rods, tubes, and articles specifically shaped or cast into various shapes for specific applications, such as handles,
Knobs, wheels, lids, sanitary utensils, etc., or rubber-like articles such as tires, shoe soles, gloves, etc. can be conveniently and advantageously produced from the compositions according to the invention. The dispersed solids provide reinforcing, hardening or decorative effects to the final product, and such products often exhibit solvent resistance. Generally, the higher the concentration of solid material that can be uniformly dispersed in the liquid, the stronger the final shaped article will be. The dispersants in the compositions of the invention therefore enable the production of homogeneous and easily processable dispersions of solids and have high proportions (often 40 wt% or more) that are still well dispersed in the solidified article.
The benefits of using such dispersants in compositions are significant as they allow for advantageous use in the production of high strength articles containing siliceous solids and having high modulus. The form of silica known to best increase the strength of molded articles is colloidal, and the present invention combines polymethyl methacrylate into an organic polymer containing high concentrations of silica as a reinforcing filler. Preferably it is used for producing shaped articles (by molding or casting). Typically, finely divided colloidal silica dispersed in organic monomers solidifies into a solid mass at a solids concentration of about 7%, but in some compositions according to the invention as much as 35% silica can be present and Furthermore, since the composition is a pourable liquid composition, it can be easily handled. Advantageously, reactive silanes such as dimethyldichlorosilane or ethoxysilanes, especially silanes containing polymerizable groups (preferably α-methacryloxypropyltrimethoxysilane), can be incorporated into the compositions of the invention. In this way, it is possible to produce dispersions with even higher proportions of silica, which makes it possible to obtain good mechanical properties, in particular toughness, of the polymerized composition. When the liquid medium is a vinyl urethane compound, optionally mixed with at least one ethylenically unsaturated copolymerizable monomer representing 50 to 150 wt% of the weight of the vinyl urethane, the composition of the invention are useful in the manufacture of dental compositions, particularly denture bases, orthodontic adhesives, and dentures. Dental compositions may include free radical generating catalyst systems, such as organic peroxide-based catalyst systems, or photocuring catalysts, such as those described in British Patent No.
Those described in No. 1408265 can be added. According to a particular embodiment of the invention: (a) a particulate siliceous material whose longest dimension is 1 μm or less; (b) a reaction product of a urethane prepolymer and an ethylenically unsaturated monomer reactive therewith; a polymerizable prepolymer containing at least two polymerizable ethylenically unsaturated groups; (where R ₁ is a hydrocarbon group having at least 6 carbon atoms or 200 or more, preferably
An organic group containing a terminal chain that is any polyether with a molecular weight of 500 to 10,000, where _R2 does not contain an organic group defined as _R1 , a hydrogen atom, or a terminal chain of 6 or more carbon atoms. hydrocarbon or substituted hydrocarbon group), an organic basic nitrogen compound of the following general formula: (where Z ₁ is the organic group defined as R ₁ above, Z ₂ and Z ₃ may be the same or different, and are defined as R ₂ above); Dispersants comprising mixtures of compounds; (d) fluorenone, substituted derivatives thereof and α-diketones of the general formula: (wherein the groups A may be the same or different and are hydrocarbon groups or substituted hydrocarbon groups); and (e) at least one photosensitizer selected from A dental composition is provided that is a fluid composition comprising: at least one reducing agent capable of reducing the photosensitizer when present. By fluid composition is meant a composition having sufficient fluidity to be readily moldable at room temperature, and by molding is meant, for example, simply molding under hand pressure. Suitably the composition has a pasty consistency. Such dental compositions can be applied to teeth, for example as fillings to cavities in teeth. The polymerizable prepolymer can be polymerized so that the composition is formed into a hard material. This polymerization reaction may hereinafter be referred to as "curing of the composition." The composition may include a solid or semi-solid polymerizable prepolymer, and since the siliceous material is also solid, a liquid ethylenically unsaturated monomer copolymerizable with the polymerizable prepolymer may be included. There often arises a need to add sufficient additives to the composition to make the composition fluid and, in particular, to give the composition a paste-like consistency. If desired, the composition can include a liquid polymerizable ethylenically unsaturated monomer even if the polymerizable prepolymer itself is a liquid. Dental compositions according to the invention can be cured by irradiation with ultraviolet radiation, ie, radiation with a wavelength of about 230-400 mμ. This composition is suitable for visible light especially 400
It can also be cured (preferably) by irradiation with visible light at a wavelength of ~500 mμ. Alternatively, a mixture of ultraviolet and visible light can be used for curing. The concentration of the photosensitizer is suitably 0.001 to 10 wt%, preferably 0.1 to 5 wt%, and the concentration of the reducing agent is
0.25-5 wt%, preferably 0.25-0.75 wt% (these percentages are based on the weight of the polymerizable material in the dental composition). The polymerizable material in the dental composition is a polymerizable ethylenically unsaturated material. Preferably, at least a portion of the polymerizable material contains a plurality of ethylenically unsaturated groups such that polymerization of the material results in a cross-linked polymer. In order for the cured dental composition to have high strength and high modulus, it is preferred that the polymerizable material has at least one cyclic group. When the polymerizable material contains a plurality of ethylenically unsaturated groups, it is preferred that the polymerizable material has at least one cyclic group in the chain between the ethylenically unsaturated groups. Dental filling compositions can be prepared by stirring together a polymerizable polymer and a siliceous filler. However, polymerizable prepolymers (sometimes used with copolymerizable monomers)
Polymerizable prepolymers (sometimes with comonomers) are viscous and therefore difficult to stir with fillers and can be difficult to achieve proper mixing. It is advantageous to dilute the material (used) with a suitable diluent to reduce its viscosity and facilitate proper mixing of the fillers. After mixing is complete, the diluent can be removed, for example by evaporation. Suitably the diluent is a copolymerizable ethylenically unsaturated monomer, the concentration of which is then reduced to the desired level. To produce dental filling compositions in which the siliceous filler adheres particularly well to the cured prepolymer, the filler is treated with a coupling agent that is reactive with both the siliceous particles and the polymerizable prepolymer. It is highly preferred to mix the filler with the polymerizable prepolymer. The coupling agent should have the effect of increasing the bond strength between the filler and the cured prepolymer. Examples of coupling agents particularly suitable for use with glass or silica include silane compounds such as γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane. . As mentioned above, the dental composition may include a liquid ethylenically unsaturated monomer copolymerizable with the polymerizable prepolymer, which renders the dental composition fluid when the polymerizable prepolymer is solid. In particular, such monomers should be included to give a paste-like consistency. Desirably, the amount of such ethylenically unsaturated monomer used is necessary and sufficient to provide the desired fluidity to the dental composition. 100wt of the weight of the polymerizable prepolymer in the filling composition, since the use of such monomers may be associated with a reduction in the strength of the dental fillings obtained from the composition.
%, preferably 50 wt. % or less of ethylenically unsaturated monomer. Examples of suitable liquid copolymerizable ethylenically unsaturated monomers (the polymers should be water-insoluble) include vinyl monomers such as vinyl esters, acrylic acid and methacrylic acid. Monomers should be non-toxic. Polyfunctional vinyl monomers, ie monomers containing two or more vinyl groups, are also suitable. Suitable monomers include, for example, glycol dimethacrylate, diallyl phthalate and triallyl cyanurate. Small amounts of pigment opacifiers and the like can be included in the composition to give the tooth base and/or the denture a brightly colored and natural appearance. The composition of the invention can be used for dental purposes by adjusting its consistency. It can be used as a filling material (for front and back teeth), a tooth polish (especially for front teeth) and an orthodontic adhesive. In particular, the composition should have a hard paste or dough-like consistency when used as a filling material, and a suitably fluid liquid when used as a tooth polish, e.g. After application to the prepared tooth surface, it should flow properly to form a smooth surface before curing. When the composition is used as an orthodontic adhesive, a wide range of consistencies can be used depending on what is being adhered to the tooth and the manner in which the adhesive is applied. For example, when bonding a dental bracket to a dentition, the composition can be in liquid form and applied to the tooth and then the bracket can be pressed against the film of the applied liquid, or the composition can be in the form of a dough and This may be applied to the back of the bracket or to a small portion of the surface of the tooth row before the tooth row and bracket are fitted together. The compositions of the invention are therefore cohesive and not powdery. The composition of the invention can be prepared in a small container (e.g. 1 g capacity)
It is preferable to pack it in a container to facilitate handling during surgery and to reduce the risk of accidental curing due to light leakage. It is preferable to clean the tooth surface before applying this composition. The teeth can be cleaned, for example, by polishing with a rotating wheel or brush, or by etching with an aqueous solution of phosphoric acid. Preferably, the liquid medium is an inert liquid that is stable at room temperature. This is because, if heating is not required for liquefying the medium, the required dispersion of the siliceous particles can be more easily achieved. However, a compound that is solid or semi-solid at room temperature can also be used as a medium, and in that case, the composition is usually prepared at a temperature higher than the melting point or softening point of the medium, and the temperature can be adjusted as appropriate. is below 250℃, preferably
Should be below 150℃. The invention will now be illustrated by examples ("parts" and "%" are by weight). Example 1 A silica dispersion was prepared using the following general procedure. The solvent or monomer was added to the dispersant in an appropriately sized beaker (eg 250ml). The dispersant was not necessarily completely dissolved at this stage. Dry silica was stirred in manually using a spatula in small portions until a gel was formed. The mixture was then stirred at high shear rate using a Greaves compressed air stirrer and stirring continued until the gel dispersion became liquid and its viscosity was minimized.
If a predetermined silica concentration is required in the dispersion, further silica is added and the above operation is repeated.
Repeat until all the total required weight of silica has been dispersed. If a dispersion containing the highest possible concentration of silica was required, silica was added in small portions until the gel no longer disintegrated by stirring at high shear rates. At this stage, more dispersant was added and stirring continued without further addition of silica to obtain a liquid dispersion. Final adjustments to the required amount of solvent were made at the end as some solvent evaporated from the open beaker during high shear stirring of the mixture. This adjustment was calculated by knowing the individual weights of all materials added and measuring the total amount at the end of the dispersion operation. According to this procedure, a 15% liquid isolate of pyrogenic silica "Aerosil A130" in methyl methacrylate (MMA) was prepared by mixing the following weights of materials in a 250 ml beaker. Aerosil A130 18g MMA 120g Di(2-ethylhexyl)phosphoric acid (DEHPA)
0.54g Armeen 12D 0.25g (Armeen 12D is from Armor Hess = AKZO
(commercial product name of long chain alkyl amine). For comparison, the silica and methyl methacrylate were stirred in the same apparatus without adding a dispersant.
The mixture became non-pourable after only 6% of silica had been added, and a gel-like mixture after only about 2% addition. Example 2 Following the procedure of Example 1, a similar dispersion of 15 wt% Aerosil A130 silica in 120 g of methyl methacrylate was made. Various total and relative amounts (Table 1) were used for each component in the dispersant. After adding 15% silica to create a liquid dispersion, the mixture was allowed to stand and its flowability was checked at selected time intervals. The number of days it took for the dispersion to gel is shown in the third column of Table 1. The gel collapsed into a liquid dispersion upon stirring again at high shear rate. Silica was added to a portion of each dispersion in portions with continued stirring until a permanent gel or thick paste was obtained. The concentration of silica present when this condition is reached is shown in column 4 of Table 1 as the maximum concentration of dispersed silica.

[Table] Example 3 Using the procedure of Example 1, 1.5 g of gel was added as a dispersant.
A 35 wt% dispersion of silica (Aerosil A130) of 120 g of methyl methacrylate monomer was made using a mixture of (2-ethylhexyl)phosphoric acid and 0.75 g of Armeen 18D (a long chain alkylamine from AKZO). The resulting dispersion was stable for about 1 hour and was a pourable liquid. After this time it gelled but could be regenerated (liquefied) by further stirring at high shear. 38wt just before reaching gel point
% of silica could be added. For comparison, each component of the dispersant was used separately in the same weight (2.0 g) as the total amount above, and a low concentration (approximately 10 wt%) of silica was added separately by the same operation. In each case the composition is a thick paste;
Even at such low silica concentrations, pourable liquids could not be created unless the two components were used together in the dispersant. Example 4 Same amount of two compounds as Example 3 (dispersant component)
were used together to make a dispersion containing 42 wt% silica (Aerosil A130) in 120 g of methyl methacrylate, but in this example 6 wt% of the silica weight.
Further α-methacryloxypropyltriethoxysilane was added. A pourable liquid dispersion was obtained. It was possible to add 48wt% silica before reaching the gelation point. For comparison, the same weights of methyl methacrylate and α-methacryloxypropyltriethoxysilane as above were used by omitting the two components of the dispersant. When silica was added in small portions as in Example 1, the mixture became non-pourable at 15% silica addition. Example 5 120g using 3wt% cetyl dihydrogen phosphate and 1.8wt% Armeen 18D based on silica
A liquid dispersion containing 28 wt% silica in methyl methacrylate was prepared. The operation was similar to Example 1. Example _{6 Mono-}
and di-propoxylated phosphoric acid;
The solvent was then evaporated. This propoxylated phosphoric acid (2.0g) was used with Armeen 18D (0.8g). A dispersion containing 38% Aerosil A130 (41 g) in 120 g of methyl methacrylate was obtained. Example 7 Mono- and di-propoxylated phosphoric acids similar to Example 6 were made, but in this example the average molecular weight of the monomethoxy polypropylene glycol was 1800. A dispersion in methyl methacrylate similar to Example 6 was made, but using 3.2 g of the above phosphoric ester and Armeen 18D (0.5 g). The mixture solidified when 3% Aerosil A13 was added. Example 8 A mixture of mono- and di-dodecyl phosphoric acids (molar ratio = approximately 1:1) was prepared as in Example 6.
19 in MMA using 1.35 g of the above mixture and 0.52 g of Armeen 18D in the same manner as in Example 1.
A liquid dispersion containing % Aerosil A130 was made. Example 9 24g of Aerosil A130 colloidal silica was taken and mixed with 1.5% Propomeen HT25 (which is a propoxylated amine from Armor Hetus) and 3%
DEHPA was used in a formulation similar to Example 1. 20% Aerosil in Methyl Methacrylate
A liquid dispersion containing A130 was obtained. Example 10 Required silica weight: 35g (Aerosil A130)
selected. The procedure of Example 1 was repeated, but this example used 10.6% propoxylated triethanolamine (approximate molecular weight 875) and 5.2% DEHPA as dispersants. Approximately 29% Aerosil A130
When dispersed in methyl methacrylate,
The mixture became non-pourable. Example 11 0.56 g di-methyl-coconut oil amine (contains primarily _C12 chains; approximate molecular weight 250) and 1.0 g
DEHPA was used. 39% silica (47g)
The dispersion of Aerosil A130 in MMA gelled upon addition to 120 g of methyl methacrylate. Example 12 A polyester chain-containing amine was made by heating a mixture of 71.3 g of ε-caprolactone, 10 ml of 3-dimethylaminopropylamine and a catalytic amount of tetrabutyltitanic acid at 160-165° C. for 1 hour. The approximate molecular weight of this reaction product was 1015. 49g of Aerosil silica was taken and based on this weight 9.7% of the above polyester amine and
Experiments were conducted according to the procedure of Example 1 using 4.7% DEHPA. Up to 32% dispersion of Aerosil (in MMA) was obtained before reaching the gel point. Example 13 Silica dispersions in various solvents and/or monomers were prepared by the following procedure, and the maximum concentration of silica was determined. Pour 125g of organic liquid into a beaker and add
0.68g of di-(2-ethylhexyl)phosphoric acid (DEHPA) and the molar ratio of “acid:amine” are
Amine was added in a 1.4:1 ratio. Silica was added with manual stirring until a thick gel formed, and the gel was then vigorously stirred at high shear using a Greaves compressed air stirrer. The mixture became fluid again and more silica could be added. Once the mixture gelled, another known amount of dispersant was added again at the same molar ratio of 1.4:1 to bring the mixture back to a fluid state and high shear stirring was repeated to add more silica. Addition of small amounts of silica and small amounts of dispersant was continued until no further changes occurred. The mixture remained thick and greasy, which could not be made more fluid by increasing the concentration of dispersant. For each organic liquid, the composition of the final mixture is determined from the known amounts of all materials added and the results are shown in the table (% by weight).

[Table] Example 14 30 g of silica was weighed and the operation of Example 2 was repeated. 3.5% DEHPA and 1.5% Armeen
A flowable dispersion containing 26% Aerosil A130 in ethyl acrylate was made using 18D (based on silica weight). Example 15 By the operation of Example 1, however, the beaker was heated to 90~
A flowable dispersion containing 21% silica (A130) in 120 g of molten ε-caprolactane was made by heating to 100°C. At this time, 4% DEHPA and 1.6% Armeen were added based on the silica addition weight (25 g).
12D was used. Example 16 Precipitated silica "Ultrasil VN3" was added to 120 g of polyol in the same manner as in Example 1.
was dispersed. The polyol is polypropylene glycol (Lancro B56) with a molecular weight of 2000.
It contained 20 equivalent percent triol (T56, molecular weight 3000). Results using various dispersant systems are shown in the table.

[Table] Example 17 The procedure of Example 16 was repeated, but instead of Ultrasil, Aerosil R972 (thermodispersion-processed silica coated with dimethyldichlorosilane to make it hydrophobic) was used, and as dispersant 1.3 g of DEHPA and
A pourable dispersion containing 30% silica was made using 0.52g of Armeen 18D. Example 18 Armeen 18D (long chain amine) and Di(2
-ethylhexyl) phosphoric acid at 1.0% and 2.5%, respectively, based on the weight of silica, to prepare pyrogenic silica-filled polyurethane compositions. Three polyurethane elastomer compositions were made from a polyol and a slight molar excess of diphenylmethane diisocyanate (MDI). When the reactants were liquid, the silica and dispersant were mixed by high shear stirring until a homogeneous mixture was obtained, and the mixture was then poured into a mold and allowed to react within the mold to form a solid polymer. Polymer samples were molded into blocks whose physical properties could be evaluated. The table shows the physical properties obtained for various silica-filled blocks in comparison with unfilled blocks of the same polyurethane.

【table】

Table: Example 19 Various concentrations of silica dispersions in methyl methacrylate monomer (containing 0.04% AD1B catalyst) were made using the method of Example 1. The dispersion was poured into a casting cell consisting of glass plates sandwiched with a 3 mm PVC gasket. Seal the casting cell to approx.
Degassed by complete immersion in ultrasound for 30 minutes. Next, the cell was immersed in an aqueous solution at 55°C and left for about 16 hours to polymerize the monomer. The bath temperature was then increased to 65°C for 1 hour and to 70°C for 3 hours. The cell was then removed and the solid sheet of silica-filled polymer was removed and placed in an oven at 110°C to complete the polymerization. Samples were cut from the sheets and their physical properties were measured. The results are shown in the table.

[Table] Example 20 35.2 g (0.1 mol) of a condensation product (bisphenol A) of 2,2-bis(4-hydroxyphenyl)propane and propylene oxide in a molar ratio of 1:2 was added to about 100 g of dicondensate. dissolved in methylene chloride,
33.6 g (0.2 mol) of this solution in 100 g methylene chloride
of hexamethylene diisocyanate under a nitrogen atmosphere. Four drops of dibutyltin dilaurate (commercially available Mellite 12) were added as a catalyst. The mixture was stirred under nitrogen for 1 hour and then heated under reflux conditions for 9 hours. The mixture was then cooled and 29g in 100g methylene dichloride
(0.2 g) of hydroxypropyl methacrylate solution was added and the mixture was then heated under reflux conditions for 3 hours. The above hydroxypropyl ester is “2
-Hydroxypropyl isomer (2.6 parts)":"1-methyl-2-hydroxyethyl isomer (1 part)". The polymerizable vinyl urethane prepolymer was then isolated as a viscous gum by cooling the mixture, treating with petroleum ether, and removing residual solvent on a rotary evaporator. A portion (50 g) of this vinyl urethane prepolymer was mixed with triethylene glycol dimethacrylate (50 g) to make liquid organic solvent (b). Liquid organic medium (100g), dimethyl long-chain alkyl tertiary amine (0.6g, Armeen DM16D from Armor Hetus), di-(2-ethylhexyl)phosphoric acid (1.00g) and methacrylsilane (1.33g, Union). Carbide, grade A174)
were premixed by stirring. 25wt% silica (Aerosil) based on the weight of this premix.
A130) is gradually added to the mixture while stirring,
Further mixing was performed on a twin roll mill and then vacuum was repeated to remove air. The resulting dispersion was transparent and had a glass-like appearance. Add 0.5% benzoyl peroxide to this dispersion while stirring.
% w/w) and N,N-dimethyl-p-toluidine (0.5% w/w) were added. This mixture hardens quickly at room temperature to form a hard, tough substance.
When it hardened in a mold, it became an excellent base for teeth. Example 21 A mixture was made from the following ingredients. Beta cristobalite sand (average particle size μm)
2425 g Methyl methacrylate monomer 1031 g Di-(2-ethylhexyl) phosphoric acid 15.3 g Armeen 18D (long chain amine) 10.7 g Silane A174 6.7 g Deionized water 1.4 g Place these ingredients in a 2-gallon laboratory magnetic ball mill24 Mixed for an hour. A low viscosity dispersion was obtained. This was poured into a series of molds to polymerize the monomer/silica mixture to form slabs. 2% by weight of "Perkadox 16" and 1% by weight of ethylene glycol dimethacrylate were added to the mixture before polymerization (% based on the weight of methyl methacrylate monomer in the mixture). Each mold was immersed in a 65°C water bath for 3 hours and then placed in another 80°C water bath for 30 hours.
The mixture was thermally polymerized by soaking for a minute. The silica-filled polymer slabs were removed from the mold and tested for their physical properties. I got the following results. ( )
The numbers within are comparative values obtained for standard silica-filled polymethyl methacrylate. Elastic modulus 12.5GN/ ^m2 (10~12) Bending strength 110~120MN/ ^m2 (107) Impact strength 4~6KJ/ ^m2 (4.3) Example 22 Two compounds in the dispersant shown in the table (weight ) was added to 18 g of methyl methacrylate monomer in a beaker of appropriate size (eg 500 ml). Pyrogenic silica ("Finsil" Finsil 600) (dry) was added manually in portions using a spatula to the weights and corresponding weight ratios indicated in the table.
Each mixture was stirred at high speed using an ILA homogenizer to uniformly disperse the silica. The viscosity of each mixture was measured with a Bruckfield RVT viscometer at 21° C. and 100 rpm. The results are shown in the table.

Table: Finsil 600 has a nominal surface area of 6 m ² /g and an average particle size of 0.1 μm. At high weight proportions of silica, the mixture is a very viscous liquid, but some fluidity can be maintained due to the presence of the dispersant. Without dispersion, the mixture of silica and methyl methacrylate is extremely viscous even at low weight proportions of silica. For comparison, when Finsil 600 and MMA monomer were stirred at high shear in an ILA homogenizer without any dispersant, the viscosity was 0.59 poise at 20% silica weight ratio, and 0.59 poise at 37% silica weight ratio. The mixture became a dry paste and non-flowing. Example 23 To a sample of the dispersion of Example 20, camphorquinone (0.75% w/w) and dimethylaminoethyl methacrylate (0.5% w/w) were added;
The resulting mixture was blended in a twin roll mill. For another sample of the dispersion of Example 20,
Camphorquinone (0.75% w/w) and long chain alkyl dimethyl tertiary amine (0.5% w/w,
"Armeen" manufactured by Armor Hetus
DM14D) was added, and the resulting mixture was also mixed in a ball mill. Samples of the above two mixtures, which were flowable paste compositions, were cured in a rheometer as described in British Standard 5199:1975 Chapter 6.4 (Resin-Based Dental Filling Materials Standard). For curing, the test sample was 11 cm long,
This was done by exposing the end of an 8 mm diameter quartz light guide. The light guide was covered along its length with a Netlon sleeve and a polyvinyl chloride syringe wrap coating. The light source was a tungsten halogen lamp (Thorn Electrical Al/230, 12 volts, 75 watts). Both samples were fully cured after 30 seconds of exposure. Example 24 Two compositions according to the invention were evaluated as orthodontic adhesives. One composition (A) had the formulation below and the other composition (B) had the formulation described in Example 23. Composition A: Gram vinyl urethane (from Example 20) 134 Triethylene glycol dimethacrylate 134 Silica (A130) 89.3 Silane (A174) 6.25 Di-(2-ethylhexyl) phosphoric acid 3.57 Tertiary amine (Armine DM16D) 3.13 Dimethyl Aminoethyl methacrylate 2.01 Camphorquinone 2.68 These ingredients were mixed as in Example 20. To measure the adhesion strength of a dental bracket to a tooth, a human tooth was first attached to a clamp, and the oral surface of the tooth was etched with a 37% phosphoric acid aqueous solution for 1 minute. The acid was then flushed away with distilled water and the tooth surface was dried with compressed air. The adhesive composition was then applied to the orthodontic bracket base and applied to the prepared tooth surface. The adhesive was then cured by transmitted or direct radiation. Various times were used and the lamp and light guide of Example 23 were used. After 10 minutes, the ligation wire was attached to the bracket and a load was applied by the wire.
The maximum load supported by the bracket before adhesive failure was recorded. The following types of orthodontic brackets were used. 1 Single edge bracket with mesh backing, which allows the adhesive composition to be cured by irradiation through the bracket (eg "perforated bracket" in the table below). 2 Brackets with foil covers that use transmitted radiation through the teeth to cure the adhesive composition (for example, Forestadent shown in the table below).

【table】

[Table] In clinical situations, the maximum force exerted by a fixation device corresponds to a supported load of approximately 2.5 kg, but the force is often much lower. Both of the abovementioned compositions can therefore be used as orthodontic adhesives and only require a short curing treatment by harmless irradiation with visible light. By using visible light curable compositions, curing can be effected by radiation through the teeth, allowing for uniform curing over the entire surface of the bracket (particularly in the case of foil brackets). Such curing cannot occur because ultraviolet light is mostly absorbed by the teeth.

Claims (1)

[Scope of Claims] 1 (a) a granular siliceous material with particles having a longest dimension of 10 μm or less; (b) a liquid or liquefiable polymerizable organic medium;
and (c) a phosphorus oxyacid of the general formula: (Here R ₁ is a hydrocarbon group having at least 6 carbon atoms or preferably 200 or more
is an organic group containing a terminal chain that is any polyether with a molecular weight of 500 to 10,000, and R ₂ is R ₁
an organic group defined as, a hydrogen atom, or 6
organic basic nitrogen compounds of the general formula: (wherein Z ₁ is the organic group defined as R ₁ above, Z ₂ and Z ₃ may be the same or different and are defined as R ₂ above); A composition comprising intimately mixed together components (a) to (c) of a dispersant comprising a mixture of compounds. 2. The composition according to claim 1, wherein the siliceous material is silica. 3. The composition according to claim 2, wherein the silica is in colloidal form. 4. The composition according to any one of claims 1 to 3, wherein the medium is an acrylic ester monomer or a methacrylic ester monomer. 5. The composition according to any one of claims 1 to 3, wherein the liquid or liquefiable organic medium contains a functional group reactive with a condensation catalyst or promoter. 6. The composition according to claim 5, wherein the functional group is a hydroxyl group. 7. The composition according to any one of claims 1 to 3, wherein the medium is a vinyl urethane compound. 8. A composition according to any one of claims 1 to 7, wherein the group R ₁ in the dispersant mixture consists of a long chain alkyl group containing from 8 to 22 carbon atoms. 9. A composition according to any one of claims 1 to 8, wherein the group R ₁ in the dispersant mixture comprises a polyoxyethylene or polyoxypropylene chain. 10. The composition according to any one of claims 1 to 9, wherein the group _R2 in the dispersant mixture is the same group as _R1 or a hydrogen atom. 11. A composition according to any of claims 8 to 10, wherein the group Z ₁ is a long-chain alkyl group containing from 8 to 22 carbon atoms. 12. A composition according to any of claims 8 to 11, wherein the groups _Z2 and/or _Z3 are hydrogen, a lower alkyl group of less than 6 carbon atoms, a phenyl group or a benzyl group. 13 The molar ratio of acid and base in the dispersant mixture is
Claim 1 which is between 0.5:1 and 100:1
The composition according to any one of items 1 to 12. 14. The composition of claim 13, wherein the molar ratio is from 1:1 to 3:1. 15. The composition according to any one of claims 1 to 14, in which a silane compound reactive with siliceous solids is present. 16. The composition according to claim 15, wherein the silane compound is a silane containing a polymerizable group. 17. A dispersion of a siliceous solid in an organic medium produced from the composition according to any one of claims 1 to 16. 18. A silica dispersion in an organic medium prepared from a composition according to any one of claims 1 to 16. 19. The dispersion according to claim 17 or 18, comprising 5 to 90% by weight of siliceous solids. 20. The dispersion of claim 19, wherein the silica has an average particle size of less than 1 μm. 21 (a) Granular siliceous material whose longest dimension is 1 μm or less. (b) a liquid or liquefiable organic medium which is a vinyl urethane compound or the reaction product of a bisphenol compound and a glycidyl alkacrylate; (c) a phosphorous oxyacid of the general formula: (Here R ₁ is a hydrocarbon group having at least 6 carbon atoms or preferably 200 or more
is an organic group containing a terminal chain that is any polyether with a molecular weight of 500 to 10,000, and R ₂ is R ₁
an organic group defined as a hydrogen atom or a hydrocarbon or substituted hydrocarbon group without a terminal chain of 6 or more carbon atoms), an organic basic nitrogen compound of the following general formula: (Here, Z ₁ is the organic group defined as R ₁ above, and Z ₂ and Z ₃ may be the same or different and are defined as R ₂ above.)
and (d) a free radical generating catalyst for the polymerization of said organic medium. 22 A vinyl urethane compound is a polymerizable prepolymer that is the reaction product of a urethane prepolymer and an ethylenically unsaturated monomer reactive therewith, and that contains at least two polymerizable ethylenically unsaturated groups. The dental composition according to claim 21. 23 The organic medium is the weight of the vinyl urethane compound.
Claim 21 or 2 which also contains 50 to 150% by weight of at least one ethylenically unsaturated monomer
The dental composition according to item 2. 24. A dental composition according to any of claims 21 to 23, wherein the free radical generating catalyst is capable of being activated by radiation having a wavelength in the range of 230 mμ to 500 mμ. 25. The dental composition of claim 24, wherein the free radical generating catalyst is activatable by radiation having a wavelength in the range of 400 mμ to 500 mμ. 26 The free radical generating system is (a) fluorenone, its substituted derivatives, and α-diketones of the following general formula. (wherein the groups A may be the same or different and are hydrocarbon groups or substituted hydrocarbon groups)
and (b) at least one reducing agent capable of reducing the photosensitizer when the photosensitizer is in an excited state. The dental composition according to Scope 25.