JPH0688039A - Surface-treated filler - Google Patents

Abstract

PURPOSE:To obtain a surface-treated filler useful for obtaining a composite resin excellent in mechanical properties and hydrolysis resistance by treating a specified spherical synthetic quartz filler with a silane coupling agent under specified conditions. CONSTITUTION:A spherical synthetic quartz filler prepared by the vaporized metal conversion process and having surface silanol groups in a density of 2.0-6.0 groups/nm<2> is treated with a silane coupling agent of formula I (wherein R1 is H or CH3; R2 is a 1-6C hydrocarbon group; X is a hydrolyzable group; m is 1-3; and n is 3-10) under conditions satisfying the relationships of formulas II and III.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the amount of silane coupling agent attached to a synthetic quartz spherical filler (filler) synthesized by the vaporized metal conversion method and the chemical bonding thereof. The present invention relates to a surface-treated filler having an excellent surface-treatment effect by controlling the amount of the reaction.

[0002]

2. Description of the Related Art Currently, a composite resin in which a polymerizable monomer is mixed with an inorganic filler is widely used for repairing a tooth defect. Generally, silica is used as the inorganic filler. The silica surface is surface-treated with a silane coupling agent for the purpose of improving the mechanical strength and hydrolysis resistance of the composite resin. Conventionally, γ-methacryloyloxypropyltrimethoxysilane (hereinafter referred to as γ-MPS) has been used as a commonly used silane coupling agent (coupling agent optimum use technology, published by Chemical Technology Research Institute), and its optimum treatment. The required amount is empirically determined from the physical property values or is determined by the relationship between the specific surface area of silica and the minimum coating area of the silane coupling agent. However, in this case, the surface state of silica and the bonding state of the silane coupling agent on the silica surface are not considered at all. If silica having different surface states is treated with the same amount of the silane coupling agent, or if treated under unsuitable conditions, a good surface treatment effect cannot be obtained. Furthermore, excellent mechanical properties and hydrolysis resistance cannot be expected for composite resins containing such inappropriate surface-treated silica.

[0003]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a surface-treated filler having an excellent surface-treatment effect, which solves the above problems. Further, it is a treatment method for obtaining the surface-treated filler. Another object is to provide a composite resin containing the surface-treated filler and having excellent mechanical properties and hydrolysis resistance.

[0004]

Means for Solving the Problems As a result of intensive studies on the composite resin having excellent mechanical properties and hydrolysis resistance, the present inventors have found that a vaporized metal conversion (having a specific surface silanol density) Vapo
The ratio of the covalent bond amount of the silanol group of the synthetic quartz true spherical filler and the silane coupling agent synthesized by the Rized Metal Combustion method (hereinafter referred to as the VMC method), and the amount of the silane coupling agent attached. We succeeded in obtaining a surface-treated filler having an excellent surface-treatment effect by controlling the ratio of the amount of covalent bonds. The inventors have found that a dental composite resin using the surface-treated filler has excellent mechanical properties and hydrolysis resistance, and completed the present invention.

That is, in the present invention, the surface silanol groups are 2.
A synthetic quartz true spherical filler synthesized by the V.M.C. method having a density of 0 to 6.0 particles / nm ² has the following general formula I (wherein R ₁ is a hydrogen atom or a methyl group, and R is ₂ has 1 to 6 carbon atoms
Hydrocarbon group, X is a hydrolyzable group, m is an integer of 1 to 3, n
Represents an integer of 3 to 10. ) A silane coupling agent represented by the formula (1) is treated so as to satisfy the following formulas I and II.

[0006]

[Chemical 2]

[0007]

[Equation 3]

[0008]

[Equation 4]

The present invention also has a surface silanol group of 2.0.
Vaporized metal with a density of ~ 6.0 pieces / nm ²
Synthetic quartz spherical fillers synthesized by the conversion (Vaporized Metal Combustion) method (hereinafter, referred to as VMC method) are added to the above-mentioned general formula I (wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is a hydrocarbon group having 1 to 6 carbon atoms, X
Is a hydrolyzable group, m is an integer of 1 to 3, and n is an integer of 3 to 10. ) A silane coupling agent represented by the formula (1) is treated so that the above formulas I and II are satisfied.

Furthermore, the present invention is a dental composite resin containing the above-mentioned surface-treated filler.

The synthetic quartz true spherical filler used in the present invention is one synthesized by the V.M.C. method, which is a gas phase reaction using metallic silicon powder as a raw material. Further, it is preferable that 2.0 to 6.0 silanol groups are present on the surface per 1 nm ² . The number of silanol groups per 1 nm ² is the number of silanol groups on the filler surface determined by titration and the blanavour,
It is calculated from the surface area measured by the equations of Brunaver, Emmett and Teller (hereinafter referred to as the BET equation). 2 silanol groups 1nm ² per.
If it is less than 0, the surface treatment effect of the silane coupling agent cannot be fully exerted, and if it is more than 6.0, the amount of silane coupling agent required for the treatment is large and the mechanical strength when mixed with resin. The hydrolysis resistance is reduced. For use as a dental composite resin, it is preferable that the filler has a particle size of 0.01 to 2 μm.
If it is less than m, the viscosity of the paste increases significantly, which is not preferable.

The silane coupling agent used for the surface treatment of the filler has a structure represented by the general formula, and the hydrolyzable group X includes a chlorine atom, an alkoxy group, an isocyanate group and the like. Specific examples include 3-methacryloyloxypropyltrimethoxysilane, 3-
Acryloyloxypropyltrimethoxysilane, 3-
Methacryloyloxypropyldimethoxymethylsilane, 3-methacryloyloxypropyltriisocyanate silane, 3- (2-methacryloyloxyethoxy) trimethoxysilane, 10-methacryloyloxydecyltrimethoxysilane and the like are used.

As a method of treating the filler with a silane coupling agent, known methods can be used. Examples thereof include a method of dispersing the filler and the silane coupling agent in an appropriate solvent and then removing the solvent, and a method of spraying the coupling agent while vigorously stirring the filler.

A feature of the present invention resides in processing so that the above equations I and II are satisfied. The number of silane coupling agents “attached” to the surface of the filler is the total number of those which are covalently bonded to the filler, hydrogen bonded, or bonded by Van der Waals force. The number of silane coupling agents “covalently bonded” to the surface is the number of silane coupling agents “adhered” that do not break the bond with the filler even after washing with a solvent or the like. The ratio of the number of surface silanol groups to the number of silane coupling agents covalently bonded is 0.4 or less, or the ratio of the number of silane coupling agents attached to the filler surface to the number of silane coupling agents covalently bonded. When it is 0.2 or less, hydrolysis resistance is lowered.

Here, the number of coupling agents adhering to the surface is calculated from the carbon content, the carbon content of the coupling agent, and the surface area of the filler obtained by performing elemental analysis of the surface-treated filler. Further, the number of coupling agents chemically bonded to the filler can be determined by washing the surface-treated filler with a solvent in which the coupling agent is dissolved and then performing elemental analysis. Examples of such a solvent include tetrahydrofuran (hereinafter referred to as THF), chloroform, acetone and the like, and THF is preferably used. Furthermore, the number of coupling agents chemically bonded can also be determined by determining the amount of the coupling agent in the solvent in which the filler has been washed by liquid chromatography and subtracting the amount from the amount attached.

The surface-treated filler of the present invention has good dispersibility and can be easily mixed uniformly with the resin or the polymerizable monomer. Furthermore, the mechanical properties and hydrolysis resistance of the composite material containing the filler can be improved. One of its uses is in dental composites. Here, the dental composite resin includes not only a cavity repair material but also a crown material, an artificial tooth, and the like. Currently used dental composite resins include bisphenol A-glycidyl methacrylate adduct (Bis-GMA), 2,2-bis (4- (methacryloxyethoxy) phenyl) propane, and 2,2 as polymerizable monomers. 2-bis (4- (methacryloxydiethoxy)
Phenyl) propane, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, urethane dimethacrylate (UDMA) and the like are used.

A polymerization initiator is used in the dental composite resin of the present invention, and known ones generally used for dentistry can be used (for example, benzoyl peroxide and tertiary amine, camphor). Quinones and tertiary amines). Further, other additives can be added if necessary. These additives include radical polymerization inhibitors, coloring pigments, ultraviolet absorbers and the like.

[0018]

The present invention will now be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

(1) Measurement of Specific Surface Area (m ² / g) of Filler The specific surface area (m ² / g) of the filler was measured with a Soaptomatic Model 1900 (manufactured by Carlo Erba Co.). The principle of measurement is the BET method.

(2) Number of surface silanol groups of the filler
(Pieces / nm ² ) of 1.00 g (Wg ) of measurement filler and 40 ml of 0.05N NaOH aqueous solution were put into a 50 ml sample tube bottle, and the suspension was stirred and suspended at room temperature for 15 hours. After that, the filler and the solution are completely separated by centrifugation, and the resulting solution is
After taking ml, neutralization titration was performed with a 0.05 N aqueous HCl solution. The aqueous HCl solution required for the neutralization is designated as Aml. Also, only 40 ml of a 0.05 N NaOH aqueous solution is put into a sample tube bottle, and the same operation is performed, and the HCl aqueous solution necessary for neutralization is made B ml. 1 nm ^{2 of} filler surface
The number of surface silanol groups (number / nm ² ) present in the was calculated by the following formula III. However, the specific surface area of the filler is a
m ² / g.

[0021]

[Equation 5]

(3) Attached to the surface of the surface-treated filler
Measurement of the number of coupling agents present Elemental analysis of the surface-treated filler, its carbon content (Csf), carbon content of silane coupling agent (Csc),
Calculate the number (number / nm ² ) of silane coupling agents adhering to 1 nm ² of the filler surface from the specific surface area (a m ² / g) of filler and the molecular weight (W) of silane coupling agent by the following formula IV. did.

[0023]

[Equation 6]

The surface-treated filler is thoroughly washed with tetrahydrofuran to completely remove the silane coupling agent adsorbed on the filler surface by a physical bond such as hydrogen bond. After vacuum drying, elemental analysis was performed in the same manner as above, and the number of silane coupling agents covalently bonded to 1 nm ² of the filler surface (number / nm ² ) was calculated in the same manner.

(4) Preparation of composite resin paste
Method and curing method of composite resin Methacrylate-based monomer, camphorquinone (referred to as CQ) as a photosensitizer, and N, N-dimethylaminoethyl methacrylate (referred to as DMAEMA) 1.0 wt% as a reducing agent are ultrasonicated. The visible light-polymerizable monomer composition dissolved by irradiation and the surface-treated silica filler were sufficiently kneaded and then degassed in vacuum to prepare a paste-like polymerizable composition. After defoaming the paste-like polymerizable composition, the paste-like polymerizable composition is injected into a hollow tube having an inner diameter of 3 mm fixed in a glass tube, and the mixture is irradiated with light for 5 minutes to be polymerized and cured, and then cured from the tube. A cured product was produced by taking out the product.

(5) Measurement of Bending Strength The cross section prepared by the method of (3) above has a diameter of 3 mm and a length of 30.
A 3-mm bending test with a distance between fulcrums of 20 mm and a crosshead speed of 2 mm / min as a test piece using a cured product of mm
S-100 (manufactured by Shimadzu Corporation) was used as a measuring device.

(6) Acceleration of boiling deterioration of composite resin
Test Method The bending test piece of (4) above was immersed in boiling water for 24 hours and then stored in 37 ° C. water for 24 hours, and the same test as in (5) above was performed.

(Example 1) 20 g of synthetic quartz true spherical filler SO25R (manufactured by Tatsumori Co., Ltd.) having an average particle size of 0.5 μm, a specific surface area of 12.3 m ² / g and a surface silanol group density of 4.0 / nm ^2.
And γ-methacryloyloxypropyltrimethoxysilane (KBM503 manufactured by Shin-Etsu Chemical Co., Ltd., hereinafter referred to as γ-MPS) in an amount 1.3 times the number of silanol groups on the surface and an aqueous ethanol solution (ethanol / H ₂ O = 70/30 vol). %) 2
It was added to 0 ml and mixed in a mortar. Stir with a pestle at room temperature until the solvent is completely evaporated. Then, it was kept at 37 ° C. for 24 hours in a constant temperature bath and heat-treated at 100 ° C. for 1 hour to prepare a surface-treated filler. By elemental analysis, γ-MPS adhering to 1 nm ² of the surface-treated filler surface
Coupling number (the number / nm ^2), also a chemical bond, such as physical bonding the gamma-MPS adsorbed and removed by washing with tetrahydrofuran, the siloxane bond 1 nm ² of the filler surface, such as hydrogen bonding The number (γ / MP ² ) of active γ-MPS was calculated. The results are shown in Table 1 below.

Example 2 Example 2 was repeated except that the amount of γ-MPS added in Example 1 was mixed in an amount 2.5 times the number of surface silanol groups. The results are shown in Table 1 below.

(Comparative Example 1) The procedure of Example 1 was repeated except that the amount of γ-MPS added in Example 1 was 0.2 times the number of surface silanol groups. The results are shown in Table 1 below.

(Example 3) SO25 used in Example 1
20 g of R and 1.5 times the number of surface silanol groups of γ-methacryloyloxypropyl silyltriisocyanate (manufactured by Matsumoto Pharmaceutical Co., Ltd. Organix SI86
0, hereinafter referred to as γ-MPSI. ) And 60 ml of hexane were mixed in a mortar. Stir with a pestle at room temperature until the solvent is completely evaporated. Then, the surface-treated filler was prepared by keeping it at 37 ° C. for 24 hours in a constant temperature bath. Otherwise, Example 1
I went the same way. The results are shown in Table 1 below.

Example 4 Example 4 was repeated except that the amount of γ-MPSI added in Example 3 was mixed in an amount 3.0 times the number of surface silanol groups. The results are shown in Table 1 below.

[0033]

[Table 1]

(Examples 5 to 8) Di (methacryloyloxyethyl) trimethylhexamethylene diurethane (referred to as UDMA manufactured by Shin-Nakamura Chemical Co., Ltd.), triethylene glycol dimethacrylate (referred to as 3G hereinafter manufactured by Shin-Nakamura Chemical Co., Ltd.) Mixed polymerizable monomer (UDMA / 3G =
70/30 wt%) and 1.0 wt% of CQ and DMAEMA respectively were added to prepare a visible light polymerizable monomer composition. 80 wt% of the surface-treated filler prepared in Examples 1 to 4 was blended with the prepared monomer composition, and the mixture was thoroughly mixed and kneaded to prepare a uniform paste-like polymerizable composition. The bending strength of the cured product and the bending strength after the boiling deterioration accelerating test were measured. The results are shown in Table 2 below. Comparative Example 2 The bending strength of the cured product and the bending strength after the boiling deterioration acceleration test were measured by the same method as in Example 4 except that the surface-treated filler prepared in Comparative Example 1 was used. The results are shown in Table 2 below.

[0035]

[Table 2]

[0036]

INDUSTRIAL APPLICABILITY As described above, the composite resin containing the surface-treated filler of the present invention has excellent mechanical strength and hydrolysis resistance and is extremely useful as a dental composite resin.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Norihiro Nishiyama Uemachi, Iwama-cho, Nishi-Ibaraki-gun, Ibaraki Prefecture

Claims (1)

[Claims] 1. Surface silanol groups of 2.0 to 6.0 / nm ²
Synthetic quartz true spherical filler synthesized by the Vaporized Metal Combustion method with the density of is represented by the following general formula I (wherein R ₁ is a hydrogen atom or a methyl group, and R ₂ is a carbon number). Is a hydrocarbon group of 1 to 6, X is a hydrolyzable group, m is an integer of 1 to 3, and n is 3-1.
Indicates an integer of 0. A surface-treated filler characterized in that the silane coupling agent represented by the formula (1) is treated so that the following formulas I and II are established. [Chemical 1] [Equation 1] [Equation 2]