JPH0764595B2 - Composite aluminosilicate glass particles - Google Patents

Description

TECHNICAL FIELD The present invention relates to novel composite aluminosilicate glass particles. More specifically, the present invention relates to composite aluminosilicate glass particles useful as an ion-exchangeable glass component of glass ionomer cement utilizing a reaction with a polymer electrolyte.

[Problems to be Solved by Conventional Techniques and Inventions] Glass ionomer cement is based on an acid-base reaction that is used by kneading ion-exchangeable aluminosilicate glass particles and an acrylic acid-based polymer electrolyte aqueous solution. Since it is a cement that can be hardened in a short time even when wet and has a mechanical strength that can withstand practical use, its application is being studied in various fields.

Among them, in the application as a dental cement, it has been widely put into practical use because it has a high affinity with hard tissues of the tooth and has a small harmful effect on the living body.

However, the biggest drawback when applied to dental cement is that the hardened cement gradually dissolves or disintegrates due to long-term contact with oral saliva (hereinafter referred to as disintegration). That is. As a result, for example, when used as an attachment of a dental prosthesis made of metal or ceramics, a gap is generated between the dental substance and the prosthesis,
Eventually, the prosthesis may be detached or a secondary disease may be caused.

The cause of such disintegration has not been clarified yet, but as one of them, fluorine ions added to the glass in order to improve the kneading operability of cement or the mechanical strength of the cement flow out over a long period of time, It is considered that the crosslinking reaction between the molecular electrolyte and the metal ion is inhibited. Therefore, in order to solve such a problem, it is required to develop a new aluminosilicate glass containing fluorine ions which does not cause outflow of fluorine ions for a long period of time.

[Means for Solving Problems] As a result of intensive studies to solve the above problems, the present inventors have made aluminosilicate glass particles substantially free of fluorine ions as a main component, and have a surface layer portion thereof. Composite aluminosilicate glass with a coating layer of glass containing only fluorine ions, compared to conventional aluminosilicate glass containing fluorine ions, mechanical strength when used as an ion-exchangeable glass component of glass ionomer cement, kneading operation The present invention has been completed by finding that a cured glass ionomer cement having a low disintegration property can be obtained without impairing its properties.

That is, the present invention relates to a surface layer of an aluminosilicate glass that does not substantially contain fluorine ions, has a thickness of 0.01 to 3 μm, and is a fluorinated compound of at least a Group I to IV metal of the periodic table,
Provided is a composite aluminosilicate glass particle having a layer comprising a fluorosilicate and one kind of an arbitrary mixture thereof and having a fluorine ion content of 1% by weight or more.

The greatest feature of the composite aluminosilicate glass particles of the present invention is that they are aluminosilicate glass particles in which fluorine ions are present only in the surface layer portion. It only needs to exist. The aluminosilicate glass particles that are the base of the composite aluminosilicate glass particles of the present invention are substantially free of fluorine ions.
The term "substantially free of fluoride ion" includes not only the absence of fluoride ion as a compound or molecule, but also the state of containing fluoride ion in an amount that does not substantially elute. In addition, a fluorine ion content of up to 0.5% by weight can be tolerated. Further, as the composition of the aluminosilicate glass, a known composition containing alumina and silica as essential components is adopted without particular limitation as long as it does not substantially contain a fluorine ion. For example, the molar ratio of alumina to silica (AL ₂ O ₃ / SiO ₂ ) is 0.2.
〜4.0, preferably 0.4 to 2.0 is suitable.

Further, the above composition may contain another metal oxide. Typical examples of such metal oxides include, for example, the periodic table I of lithium, sodium, potassium and the like.
Oxides of metals of the group, magnesium, calcium, strontium, barium, oxides of metals of the periodic table group II such as zinc, boron, yttrium, oxides of elements of the group III of the periodic table such as lanthanum, titanium, Examples thereof include oxides of metals belonging to Group IV of the periodic table such as zirconium, hafnium and tin, and oxides such as phosphorus oxide.

These metal oxides may be used alone or in combination of two or more. Further, the proportion of the metal oxide is 5 to 75 parts by weight, preferably 10 to 65 parts by weight, based on 100 parts by weight of the total amount of alumina and silica, and forms a glassy, that is, amorphous solid substance. To do.

As a method for producing the aluminosilicate glass particles, a known method is adopted without particular limitation. Generally, a mixture containing at least an aluminum compound and a silicon compound is melted,
It is obtained by a method of rapidly cooling (melting method). Examples of the aluminum compound include alumina, aluminum phosphate, and aluminum hydroxide, and examples of the silicon compound include silica, sodium silicate, calcium silicate, and the like. In addition to the above-mentioned metal oxides as optional additives, metal phosphates such as sodium phosphate and calcium phosphate, metal carbonates such as calcium carbonate, strontium carbonate, potassium carbonate and sodium carbonate, sodium hydroxide and zinc hydroxide. And metal hydroxides.

In the above melting method, the method of making the aluminosilicate glass into particles (powder) is not particularly limited. For example, aluminosilicate glass is obtained in the form of a lump, and it is crushed by a method, granulated when the melt is rapidly cooled, or by the strand method described on page 219 of the Glass Handbook (Asakura Shoten, 1975). Examples thereof include a method of forming fibrous particles.

In addition to the above, as a method of producing aluminosilicate glass particles, a method of hydrolyzing at least aluminum silicon and a metal alkoxide and then calcining by a known method (sol-gel method) can be mentioned.

Examples of the above-mentioned aluminum alkoxide include aluminum-tri-sec-butoxide and aluminum-tri-
Isopropoxide, aluminum-tri-ethoxide and the like, and silicon alkoxides include silicon tetramethoxide and silicon tetraethoxide.
Further, as a metal alkoxide as an optional additive component, sodium methylate, calcium diethoxide,
Boron triethoxide, titanium tetrabutoxide, zirconium tetrabutoxide, triethyl phosphate and the like are generally used.

In the above sol-gel method, the method for obtaining the aluminosilicate glass in the form of particles (powder) is not particularly limited. For example, an aluminosilicate glass is obtained in the form of a lump, a method of pulverizing the aluminosilicate glass, a method of spheroidizing the pulverized product by passing it through a flame in a dispersed state, and a method of hydrolyzing a metal alkoxide dispersed in a solution The method of doing it is mentioned.

In the present invention, 0 on the surface layer of aluminosilicate glass.
The fluorine ion-containing layer having a thickness of 01 to 3 μm may contain fluorine ions at a fluorine content of 1% by weight or more, preferably 3% by weight to 60% by weight.

The formation of the fluorine ion-containing layer is a state in which fluorine ions are injected or impregnated into the surface layer of the aluminosilicate glass, a surface layer portion of the aluminosilicate glass and a fluorine-containing inorganic compound are mixed and solidified, or the aluminosilicate glass surface contains. The fluorine compound or a mixture of the fluorine-containing compound and a substance not containing fluorine such as metal oxide or aluminosilicate glass may be in a layered state.

Therefore, the fluorine ion-containing layer is a fluorosilicate such as fluoroaluminosilicate in which a part of the base aluminosilicate glass is fluorinated, a fluorinated compound of a metal of Group I to IV of the periodic table or various metals described later. Is a layer containing at least one kind of a fluorinated compound or a mixture thereof.

When the fluorine ion content of such a fluorine ion-containing layer is less than 1% by weight, the amount of elution of fluorine ions from the fluorine ion-containing layer is insufficient, and for example, when it is used as a component of glass ionomer cement, sufficient curing is achieved. It becomes difficult to obtain the mechanical strength of the body.

The thickness of the fluorine ion-containing layer is 0.01 to 3 μm, preferably 0.05 to 2 μm. When the thickness is 0.01 μm or less, when the composite aluminosilicate glass particles of the present invention are used as a component of the glass ionomer cement, the mechanical strength of the cured product is not sufficient, and conversely if it is too thick, Over a long period of time, fluoride ions tend to elute and the disintegration rate tends to increase.

In the present invention, the shape, size, etc. of the composite aluminosilicate glass particles are not particularly limited, but when used as a component of the glass ionomer cement, spherical shape, whiskers in consideration of the kneadability with the polymer electrolyte solution. A shape such as a shape or an irregular shape is common, and the size is preferably an average particle diameter or a diameter of 0.1 to 100 μm, particularly 0.3 to 50 μm.

The method for producing the composite aluminosilicate glass particles of the present invention is not particularly limited, but generally, a compound capable of supplying fluorine ions to the surface of the aluminosilicate glass particles substantially free of fluorine ions, for example, Fluorine gas, sulfur hexafluoride, Freon (trade name of fluorohydrocarbons), fluorine-containing gas such as hydrogen fluoride gas, solid or liquid fluorinating agent such as ammonium fluoride, hydrofluoric acid, or Fluoroaluminosilicate or a part of aluminum thereof substituted with other metal, fluorinated compounds of Group I metal of the periodic table such as lithium fluoride, potassium fluoride and sodium fluoride, magnesium fluoride, calcium fluoride, Fluorides of Group II metals of the periodic table such as barium fluoride, strontium fluoride and zinc fluoride, Periodic Table Group III metal fluorides such as aluminum fluoride, Group IV metal fluorides such as stannous fluoride, and complex salts of Group IV metal groups such as potassium zircon fluoride and sodium zircon fluoride. And natural fluorine-containing minerals such as cryolite, and fluorine ion-containing glass. It is also possible to use a mixture of these substances capable of supplying fluorine ions and an inorganic substance not containing fluorine ions, such as aluminosilicate glass powder or metal oxide powder.

The treatment method will be described more specifically. First, in the case of treating with a fluorine-containing gas, the aluminosilicate glass powder and the gas may be heated and brought into contact with each other using an electric furnace or the like. Further, in the case of liquid or soluble substances such as ammonium fluoride and hydrofluoric acid, aluminosilicate glass particles and these liquids or solutions are mixed, dried and heated. Furthermore, sodium fluoride, magnesium fluoride,
When it is a solid such as fluorine-containing glass, they are mixed well with a mortar, a ball mill, a gargling machine, a mixer and the like. It is preferable to add a liquid medium such as water or alcohol and mix and disperse it in a paste state or a slurry state.

The mixture thus obtained is further dried and heated after removing most of the medium by air drying or a rotary evaporator.

Drying can be done by air drying, but it is generally 100 ℃
Perform overnight at a temperature of ~ 250 ° C. The heat treatment may be generally performed at 250 ° C to 1100 ° C for about 1 to 3 hours. When the fluorinated compound used is an easily reactive fluorine compound such as ammonium fluoride, lithium fluoride, potassium fluoride, sodium fluoride, magnesium fluoride, calcium fluoride, or contains 1% by weight or more of fluorine ion. When glass powder is used, a mixture with glass particles containing substantially no fluoride ions is used at 250 ° C to 1100 ° C for 5 minutes to
It is possible to achieve the purpose sufficiently by heating for 1 hour.

The particle size of the composite aluminosilicate glass particles of the present invention should be measured with a particle size distribution meter, the shape thereof with a scanning or transmission electron microscope, and the thickness of the fluorine ion-containing glass layer should be measured with an X-ray microanalyzer. You can The components and composition of the fluorine ion-containing layer can also be determined by using an X-ray microanalyzer and the structure of amorphous or crystalline can be determined by using an X-ray diffractometer. It is possible to control the thickness and the fluorine content of the fluorine ion-containing layer.

The composite aluminosilicate glass particles of the present invention are suitably used as a glass ionomer cement in combination with a polymer electrolyte.

As the polymer electrolyte, any known polymer may be used without limitation as long as it reacts with the composite aluminosilicate glass powder and solidifies. For example, acrylic acid,
Homopolymers or copolymers of unsaturated monocarboxylic acids such as vinyl acetic acid, crotonic acid, methacrylic acid, the above unsaturated monocarboxylic acids and maleic acid, fumaric acid, aconitic acid, citraconic acid, mesaconic acid, itaconic acid , Tiglic acid, a copolymer with an unsaturated polycarboxylic acid such as 1-butene-1,2,3-tricarboxylic acid, a copolymer of the unsaturated polycarboxylic acids with each other, or the above-mentioned unsaturated monocarboxylic acid. Examples thereof include a copolymer of carboxylic acid or unsaturated polycarboxylic acid and vinylphosphonic acid.

The molecular weight of these polymers is not particularly limited as long as the viscosity of an aqueous solution having a concentration of 40 to 70% by weight can be 500 to 10,000 cps at 23 ° C., but the molecular weight is usually 5,000 to 200,000.
Is preferred.

The mixing weight ratio of the polymer electrolyte and the composite aluminosilicate glass particles in the glass ionomer cement is usually
1: 1 to 1: 6 are preferably adopted.

When the polyelectrolyte is used as a pre-prepared aqueous solution, the concentration is 30-80% by weight, preferably 40-60% by weight.
And the viscosity at that time is 500 to 9000 cps, preferably 900
~ 4000cps is adopted. In addition, the polymer electrolyte aqueous solution contains malonic acid, tartaric acid, malic acid, citric acid, etc. in order to improve the kneading operability and the hardening characteristics and the hardening time when kneaded with the composite aluminosilicate glass particles. Phosphoric acids such as organic acids, orthophosphoric acid, pyrophosphoric acid, and polyphosphoric acid, or fluorine compounds such as aluminum fluoride, potassium fluoride, potassium hexafluorosilicate, sodium hexafluorotitanate, and potassium hexafluorozirconate are added. There is a case.

[Action and Effect] Since the composite aluminosilicate glass particles of the present invention contain fluorine ions only in the surface layer portion, when they are subjected to the action of acid or alkali, they release fluorine ions temporarily, but once in the coating layer. When the fluoride ion of is consumed, the elution amount thereof is significantly reduced thereafter.

Therefore, when the composite aluminosilicate glass particles of the present invention are used as the glass powder of the glass ionomer cement, the fluidity at the time of kneading the glass powder and the aqueous solution of the polymer electrolyte and the mechanical strength of the cured product decrease. Without
In addition, the collapse resistance can be significantly improved.

Although the mechanism of manifestation of such hardening is not yet clear, the present inventors presume as follows.

First, there is the curing mechanism of ionomer cement consisting of aluminosilicate glass particles and aqueous solution of polyelectrolyte having carboxylic acid group. This is because the metal ion eluted from the aluminosilicate glass by mixing both and the carboxylic acid group of polyelectrolyte. The reaction with is considered to be the main reaction.
However, in practical use, the fluorine ions added to the aluminosilicate glass elute at the same time as the metal ions and act on the main reaction, and play an important role in the fluidity during the kneading operation and the development of mechanical strength after curing. It is believed that.

Although the mechanism of action of this fluoride ion has not yet been clarified, generally coexisting fluoride ion acts as a masking agent for metal ions and temporarily suppresses the curing reaction during kneading, It is considered that, while maintaining the fluidity of the kneaded product, at the same time, it also promotes the formation of a hydrate of an inorganic salt, which is considered to affect the development of mechanical strength of the cured product after kneading.

Thus, although the presence of fluorine ions plays a very important role from the time of kneading to the early stage of curing, if they continue to be eluted from the glass particles for a long period of time, on the contrary, the reaction between the metal ions and the polymer electrolyte causes The formed cross-links are dissociated or broken, which causes re-dissolution or disintegration of the hardened polymer electrolyte. Therefore, ideally, it is presumed that the most preferable form is that an appropriate amount of fluorine ions coexist from the time of kneading to the initial stage of curing and the supply thereof is suppressed after the curing reaction has sufficiently proceeded.

However, the composite aluminosilicate glass provided by the present invention contains fluorine ions only in the surface layer portion of the particles as described above, and therefore, compared to conventional aminosilicate glass containing a large amount of fluorine ions up to the inside of the particles. It is presumed that fluorine ions intervene in the reaction during the period from the Japanese time to the early stage of curing, and thereafter the supply decreases as the curing progresses, and finally the state close to the ideal described above is reproduced.

The composite aluminosilicate glass particles of the present invention show excellent properties as a glass ionomer cement as described above, or as a filler such as a composite resin, or
It is also useful as a sintering raw material, a sintering aid, or a glass ceramic raw material, which utilizes the fact that the melting temperature of the surface is lower than that of the central portion. Further, since the amount of the fluorine compound used is small, the production of toxic fluorine-containing gas is small at the time of production, and it is an extremely advantageous material from the viewpoint of environmental hygiene and damage to the device.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. The definitions of various quantities relating to the properties of the materials shown in this section and the examples and the measuring methods thereof are as follows.

(1) Average particle size The obtained particles were dispersed in water and measured with a particle size distribution meter (Microtrac Lead & Northlap Co.). The measurement principle is based on the measurement of a scattered diffraction image by laser light.

(2) Structure The X-ray diffraction of the powder was measured using an X-ray diffraction measuring device (JEOL) to investigate the structure (morphology) of the composite oxide.

(3) Composition and thickness of glass coating layer The composition of the powder was measured with a fluorescent X-ray analyzer (Rigaku Denki).
The thickness of the fluorine ion-containing glass layer of the composite aluminosilicate glass and the content of fluorine were determined by using an X-ray microanalyzer equipped with an LEDI dispersive crystal for the cross section of the glass particles.

(4) Hardening time of cement According to the coagulation test of dental zinc phosphate cement described in JIS T6602.

That is, a Teflon mold having an inner diameter of 10 × 10 × 2 mm was filled with cement prepared by kneading glass powder and cement liquid for 1 minute to flatten the surface. 2 from the start of training
After the lapse of minutes, this was transferred to a constant temperature bath at a temperature of 37 ° C and a relative humidity of 100%. Then, a Vickers needle having a weight of 560 g (needle cross-section seat 1 mm ² ) was gently dropped on the surface of the test piece, and the time when no needle mark was left was counted from the start of kneading as the curing time.

(5) Cement operation time The measuring method of glass ionomer cement described in British Standard BS6039 was referred to.

That is, in a room of 23 ± 1 ° C., a mixture of glass powder and cement liquid is filled into a mold with an inner diameter of 8 × 10 × 5 mmφ, and a needle with a cross-sectional diameter of 2 mm is gently dropped to The operation time was calculated from the time when the kneading was started when the trace of the cross section was not left clearly.

(6) Powder-liquid ratio The weight ratio (P / L) of the glass powder (Pg) to the cement liquid (Lg) was used.

(7) Compressive strength According to JIS T-6602 zinc phosphate cement crushing resistance test.

That is, cement mixed with glass powder and cement liquid for 1 minute is put into a mold, and this is placed at a temperature of 37 ° C. and a relative humidity.
After being kept in a 100% thermostat for 1 hour, the cured product was taken out of the mold. The size and shape of the test piece is 12 mm x 6 m
It has a cylindrical shape of mφ. After that, this test piece was kept in distilled water at 37 ° C for 23 hours, and then Tensilon (manufactured by Toyo Baldwin Co., Ltd.) was used to crosshead speed 1 mm / min.
The pressure was applied until the test piece was crushed. The crushing resistance at this time was defined as the compressive strength (kg / cm ² ).

(8) Disintegration rate Based on the JIS T6602 disintegration rate test.

That is, cement prepared by kneading glass powder and cement liquid for 1 minute was placed in a mold, and a nylon wire having a diameter of 0.148 mm was inserted. After keeping this at 37 ° C. and 100% relative humidity for 1 hour, the mold test piece was taken out. The size and shape of the test piece is a disk shape of 5 mm x 15 mmφ. Immediately thereafter, a glass bottle having an internal volume of known weight of about 100 ml was placed, stoppered and weighed. The difference between this weight and the total weight of the bottle and nylon wire is calculated and used as the weight of the test piece. 50 ml of distilled water was added to this, the test piece was suspended in water with a fine wire, lightly stoppered and kept in a constant temperature bath at a temperature of 37 ° C. for 7 days. After taking out the nylon wire and the test piece, the glass bottle was heated on a water bath to evaporate the water, and further dried in a thermostat at a temperature of 150 ° C until the weight change of the bottle became 0.5 mg or less per 24 hours. . The original glass bottle weight was then subtracted from the glass bottle weight thus obtained to obtain the weight of the evaporation residue. The ratio of the weight of the evaporation residue to the weight of the test piece was determined, and this value was used as the disintegration rate.

(9) Fluorine ion elution amount The test piece (5 × 15 mm ¢) was heated at the same temperature as the disintegration rate measurement.
It was kept in distilled water (50 ml) at 37 ° C for 7 days. During this period, the amount of fluorine ions eluted in distilled water was determined using a capillary electrophoresis analyzer (manufactured by Shimadzu Corporation). From this value, the number of milligrams eluted from 1 gram of the test piece was obtained by calculation, and this was taken as the amount of fluorine ion eluted.

Example 1 To a mixed solution of 0.01N hydrochloric acid (24 ml) and ethanol (320 ml) was added 333 g of tetraethyl silicate (Si (OC ₂ H ₅ ) ₄ , manufactured by Nippon Corcoat), and the mixture was refluxed at 80 ° C. for 2 hours. In the solution,
Aluminum tri-sec-butoxide (Al (O-sec-C ₄
H ₉ ) ₃ , 551 g manufactured by Tokyo Kasei) and triethyl phosphate ((C ₂ H
₅ O) ₃ P = O, by adding Wako Pure Chemical) 58 g, it was refluxed for 1 hour. This solution is referred to as solution A.

Granular metallic calcium (Wako Pure Chemical Industries, Ltd.) 19.2 g ethanol 4
In addition to l, calcium was reacted with ethanol when refluxed at 60 ° C. for 2 hours to produce calcium diethoxide, which was dissolved in ethanol. This reaction solution is designated as solution B.

After adding solution A to solution B, and further adding 62 g of a methanol solution containing 28% sodium methylate (manufactured by Wako Pure Chemical Industries), 80
After refluxing at 0 ° C for 1 hour, the liquid was cooled to room temperature. A mixture of 1.2 l of ammonia water and 1.2 l of methanol prepared in advance was gradually added to the liquid thus obtained with stirring. Furthermore, when kept at room temperature overnight, an agar-like gel was formed. The gel obtained is dried at 60 ° C for 24 hours and then dried at 800
When heated at 0 ° C. for 1 hour, a white powder was obtained.

Take the obtained white powder in a polyethylene beaker, crush it with a polypropylene rod, and then
It was sifted through 0 mesh. The powder that has passed through the sieve is used as a metal oxide powder.

Then, the metal oxide powder at a rate of 25g using a multi-tube burner, the hydrogen (2.3 nm ³ / h), air (2.0 Nm ³ /
Hour) and oxygen (0.75 Nmm ³ / h). The particles in the raw material powder were melted in a flame, cooled down to a cyclone, and collected by the cyclone.

The obtained particles had an average particle size of 5, 3 μm and an amorphous spherical shape. According to the composition analysis, silica 35.6%, alumina 42.3% by weight, calcium oxide 10.0%, phosphorus pentoxide 8.4% by weight,
The amount of sodium oxide was 3.7% by weight, which was equal to the composition ratio calculated from the charged amount. Compositional analysis by an X-ray microanalyzer showed that the composition was uniform between particles and within particles.

As described above, spherical aluminosilicate glass powder (G-1) was obtained. Next, 10 g of spherical aluminosilicate glass powder (G-1) was kneaded with 0.44 g of ammonium fluoride (manufactured by Wako Pure Chemical Industries) and an appropriate amount of water in an alumina mortar to form a paste, and further while blowing dry air. Kneading was continued to make a powder. The powder at 100 ° C
After being dried for 12 hours, it was calcined at 250 ° C. for 1 hour to obtain a modified aluminosilicate glass powder whose surface was coated with fluorine-containing glass.

The shape, particle size, and composition ratio of the obtained particles other than fluorine were the same as those of G-1. According to an X-ray microanalyzer, the thickness of the fluorine ion-containing glass layer was about 0.3 μm, and the fluorine ion concentration in the fluorine ion-containing glass layer was about 6% by weight. Also, according to the measurement of x-ray diffraction, it was confirmed that the obtained particles were amorphous and the coating layer was glass.

Examples 2 to 7 Spherical composite aluminosilicate glasses were produced in the same manner as in Example 1 except for the amount of ammonium fluoride and the heating conditions for forming the fluorine ion-containing glass layer. Table 1 shows the conditions for forming the fluorine ion-containing glass layer and the properties of the obtained particles.

Examples 8 to 11 A spherical composite aluminosilicate glass was prepared in the same manner as in Example 1 except that the type and amount of fluoride and the heating conditions for forming the fluorine ion-containing glass layer were as shown in Table 2. Manufactured. Table 2 shows the formation conditions of the fluorine ion-containing glass layer and the properties of the obtained particles.

Example 12 The agar-like gel obtained in Example 1 was dried at 60 ° C. for 24 hours, heated at 800 ° C. for 1 hour, further heated at 1500 ° C. to melt, and then put into water. Quenched. The resulting glass was ground with a vibrating ball mill and passed through a 420 mesh screen. The powder that has passed through the sieve is used as ground aluminosilicate glass powder (G-2).

Next, 10 g of G-2 is added with 1.50 g of ammonium fluoride and 50 g of water.
After being dispersed in an aqueous solution of 100 ml, the mixture was pulverized by a rotary evaporator at 40 ° C. The powder at 100 ℃ 1
After drying for 2 hours, it was calcined at 600 ° C. for 1 hour.

The shape of the obtained particles was irregular, the average particle diameter was 4, 6 μm, and the composition ratio other than fluorine was the same as that of G-1. According to an X-ray microanalyzer, the glass layer containing fluorine ions had a thickness of about 1 μm and a fluorine ion concentration of about 8% by weight. Moreover, the obtained particles were amorphous.

Examples 13 to 16 Based on the conditions described in Example 1, composite aluminosilicate glass was produced. The properties of the obtained particles are shown in Table 3.

Example 17 10 g of the spherical aluminosilicate glass powder (G-1) produced in Example 1, 2,5 g of the ground aluminosilicate glass powder produced in Example 12 and 0.33 g of sodium fluoride.
An appropriate amount of water was added to form a slurry, and the mixture was sufficiently kneaded in a mortar. Then, dry air was blown to the slurry to vaporize the water. The obtained powder was dried at 100 ° C. for 1 hour and then heated at 1000 ° C. for 5 minutes to obtain a composite aluminosilicate glass.

The obtained composite aluminosilicate glass particles have an average particle diameter of 5.7 μm and the thickness of the fluorine ion-containing glass layer is 0.4 μm.
m, amorphous, and spherical. The fluorine ion-containing glass layer contained 6% by weight of fluorine ions. The composition other than the fluorine ion was the same as in Example 1.

Application Example 1 2.0 g of composite aluminosilicate glass produced in Example 1
In the meanwhile, a commercially available glass ionomer cement (combined, Fuji Ionomer, type I manufactured by Denso Dental Industry Co., Ltd.) was kneaded at a ratio of 1.0 g, and operation time, curing time, compressive strength, disintegration rate And the amount of fluoride ion elution was measured.

As a result, curing time 5 minutes 30 seconds, operation time 2 minutes, compressive strength
1750Kg / cm ² , disintegration rate 0.11%, and fluoride ion elution rate 0.
It was 30 mg / g.

Use Examples 2 to 17 The physical properties of the composite aluminosilicate glass produced in Examples 2 to 17 when kneaded with the glass ionomer cement liquid described in Use Example 1 were examined. The results are shown in Table 4.

Comparative Example 1 Using silica, alumina, cryolite, aluminum phosphate, calcium fluoride, and aluminum fluoride as raw materials,
In the same manner as in Example 17, the average particle size was 5.6 μm, the composition (weight ratio, SiO ₂ 33.5, Al ₂ O ₃ 32.0, CaO 9.9, Na ₂ O 2.5, P ₂ O ₅
A fluoroaluminosilicate glass powder of 8.1 F 13.9) was obtained.

The physical properties of 1.7 g of the fluoroaluminosilicate glass powder mixed with 1.0 g of the glass ionomer cement liquid described in Application Example 1 were examined.

Curing time 5 minutes 20 seconds, operation time 2 minutes 10 seconds, compressive strength 1650Kg
/ cm ² , disintegration rate 0.87%, and fluoride ion elution amount 3.59 mg / g
Met.

Comparative Example 2 As in Comparative Example 1, the average particle size was 4.9 μm, the composition (weight ratio, SiO ₂ 36.8, Al ₂ O ₃ 35.7, CaO 10.9 Na ₂ O 2.7, P ₂ O ₅
8.9, F 5) fluoroaluminosilicate glass powder was obtained. This fluoroaluminosilicate glass powder was treated with ammonium fluoride by the method described in Example 1 to obtain a fluoroaluminosilicate glass powder whose surface was further coated with a glass containing a large amount of fluorine.

1.7 g of the obtained fluoroaluminosilicate glass powder
1.0 g of the glass ionomer cement liquid described in Application Example 1
The physical properties when kneaded with were investigated. The curing time was 5 minutes and 50 seconds, the operation time was 3 minutes, the compressive strength was 1550 Kg / cm ² , the disintegration rate was 0.79%, and the fluorine ion elution amount was 3.17 mg / g.

Comparative Example 3 Using 10 g of the spherical aluminosilicate glass powder (G-1) obtained in Example 1 and 0.1 g of ammonium fluoride,
In the same manner as in Example 1, the thickness of the glass coating layer was 0.3 μm.
m, the content of fluorine ions was 0.5% by weight, and glass particles having the same composition as that of the composite aluminosilicate glass obtained in Example 1 except for the fluorine ions and the shape and size of the particles were obtained.

The physical properties of 2.0 g of the obtained glass particles when kneaded with 1.0 g of the glass ionomer cement liquid described in Application Example 1 were examined. Curing time 25 minutes 30 seconds, operation time 21 minutes, compressive strength 620 kg /
The content was cm ² , the disintegration rate was 18%, and the fluoride ion elution amount was 0.25 mg / g.

Claims (1)

[Claims] 1. A surface layer of an aluminosilicate glass substantially free of fluorine ions, having a thickness of 0.01 to 3 .mu.m, at least a metal fluoride of Group I to IV of the periodic table, a fluorosilicate, and any of these. Consists of one kind of mixture,
And composite aluminosilicate particles having a layer containing 1% by weight or more of fluorine ions