JP4822314B2 - pH adjusting adhesive composition - Google Patents

Description

The present invention relates to a one-pack self-etching primer and a one-pack one-step bonding material for bonding a tooth and a dental restorative material.

In dental practice, caries treatment is carried out by removing carious portions of teeth and forming cavities, and after treating dental cavities with dental adhesive, filling with composite resin. However, when the shelf life of these materials is poor, dental adhesion is insufficient, and pulp stimulation and secondary caries composite fall off are problematic.

In the case of dental adhesives, in particular, a one-component self-etching primer or a one-component one-step bonding material containing a (meth) acrylate monomer having an acidic group in the molecule and water as essential components is a product shelf. The lifespan is poor and inadequate adhesion after surgery has been pointed out. This is due to hydrolysis in an acidic solution (pH is too low) such as a (meth) acrylate monomer having an acidic group or a coexisting (meth) acrylate monomer. Yes.

Macromolecule Chemistry Physics, Volume 200, pages 1062-1067 (1999) reports that phosphonic acid group-containing monomers that do not have ester linkages prevent adhesion degradation due to hydrolysis and improve shelf life of products There is.

Japanese Patent Application Laid-Open No. 2003-89613 and Journal of Dental Research, Vol. 83, Special Issue, Title No. # 2661 include self-etching containing N-methacryloyl-ω-aminoalkylphosphonic acid and N-methacryloylglycine The primer is reported to improve the degradation of adhesion performance due to hydrolysis.

However, even when acidic monomers that do not have an ester group in the molecule are not hydrolyzed under strong acidic conditions, if radically polymerizable monomers having an ester bond coexist, they are eventually hydrolyzed. Product shelf life is reduced.

JP-A-2001-49199 discloses that (a) a water-insoluble acidic group-containing polymerizable monomer and / or salt thereof, and (b) water, and has a pH of 1.0 to 6.0. It has been reported that the characterized substantially transparent adhesive composition exhibits excellent adhesion to enamel and dentin, particularly adhesion durability in water.

According to this publication, water-insoluble acidic group-containing monomers have poor adhesion to teeth because of their poor permeability to teeth. Therefore, “To improve water permeability and adhesion by making water-insoluble acidic group-containing monomers into water-soluble salts using basic compounds such as sodium hydroxide and amines. I was able to do it. "

Further, the publication suggests that the pH of the adhesive composition is in the range of 1.0 to 6.0. The adhesive composition shows a high adhesive strength at a pH of 1.0 to 2.5, but when it contains a water-soluble acidic group-containing radical polymerizable monomer, the shelf life of the adhesive composition is also reduced by hydrolysis. It has become clear to do.

That is, in this publication, there is an aim to improve the adhesiveness by water-solubilizing a water-insoluble acidic group-containing monomer in advance with a basic compound or in water, but hydrolysis is performed by adding a basic compound. It is not assumed at all about improving shelf life by avoiding the above.

Thus, the deterioration of the shelf life of products due to hydrolysis in a one-component self-etching primer or a one-component one-step bonding material that contains water-soluble acidic group-containing radically polymerizable monomers and water as essential. No proposal has been made for a solution technique for the problem of lowering the bonding performance.

JP 2001-49199 A JP 2003-89613 A Macro Molecule Chemistry Physics 200, 1062-1067 (1999) Journal of Dental Research, Volume 83, Special Issue, Presentation No. # 2661

Conventionally, a one-component self-etching primer and a one-component one-step bonding material containing a water-soluble acidic group-containing radical polymerizable monomer and water as essential components have poor shelf life, and the hydrolysis of monomers having acidic groups is difficult. There is a problem that the adhesive effect is remarkably lowered due to decomposition or the like.

 Alkali is previously applied to an adhesive composition such as (A) a water-soluble acidic group-containing radically polymerizable monomer and (B) one-component self-etching primer or one-component one-step bonding material containing water as an essential component. The shelf life of the pH-adjusted adhesive composition with added pH adjusted was studied, and it was found that the pH-adjusted adhesive composition adjusted to a pH value of 2.6 to 3.5 maintained shelf life and adhesive performance. As a result, the present invention was completed.

As described above, it is a one-component self-etching primer or a one-component one-step bonding material containing water-soluble acidic group-containing (meth) acrylate monomers and water as essential components, and an alkali is added in advance. The pH-adjusted adhesive composition of the present invention adjusted to pH 2.6 to 3.5 by, for example, is used to solve the conventional problems, maintain the shelf life of the adhesive composition, and maintain the adhesive performance. Since the treatment of dental caries and the preservation of teeth are made more reliable, it can greatly contribute to dentistry and is a valuable dental adhesive.

  In the present invention, an acidic group-containing radical polymerizable monomer that is soluble in water by 5% or more is defined as “(A) a water-soluble acidic group-containing radical polymerizable monomer”.

In the present invention, (A) the water-soluble acidic group-containing radical polymerizable monomer is 6- (meth) acryloxyhexylphosphonoacetate, 6- (meth) acryloxyhexylphosphonopropionate. preferable. Compared with other water-soluble acidic group-containing radical-polymerizable monomers, these components have a composition that extends shelf life while maintaining adhesion.

Among the monomers conventionally used as dental adhesive monomers, all “water-soluble acidic monomers” can be used, especially phosphoric acid groups such as phosphate ester groups, phosphonate groups, and pyrophosphate groups in the molecule. Polymerizable monomer having at least one group, carboxyl group, carboxyl acid anhydride group, sulfonic acid group, and the like, and containing a polymerizable group such as (meth) acryloyl group and N- (meth) acryloylamide group , And alkali metal salts and alkaline earth metal salt amine salts of radically polymerizable monomers having an acidic group. As an abbreviation of the compound in the present invention, for example, methyl (meth) acrylate means methyl methacrylate and methyl acrylate.

Examples of phosphonic acid group-containing radical polymerizable monomers include 3- (meth) acryloxypropyl-3-phosphonopropionate, 3- (meth) acryloxypropylphosphonoacetate, 4- (meth) acrylic acid. Loxybutyl-3-phosphonopropionate, 4- (meth) acryloxybutylphosphonoacetate, 5- (meth) acryloxypentyl-3-phosphonopropionate, 5- (meth) acryloxypentylphosphono Acetate, 6- (meth) acryloxyhexyl-3-phosphonopropionate, 6- (meth) acryloxyhexylphosphonoacetate, bis [2- (meth) acryloxyethyl] hydrogen phosphate, 2- ( (Meth) acryloyloxyethyl dihydrogen phosphate, 3- (meth) acryloyl Xylpropyl dihydrogen phosphate, 4- (meth) acryloyloxybutyl dihydrogen phosphate, 5- (meth) acryloyloxypentyl dihydrogen phosphate, 6- (meth) acryloyloxyhexyl dihydrogen phosphate, N- (meta ) Acrylyl-ω-aminopropylphosphonic acid, and alkali metal salts and alkaline earth metal salt amine salts thereof.

Examples of the sulfonic acid group-containing radical polymerizable monomer include styrene sulfonic acid, 2-sulfoethyl (meth) acrylate, 6-sulfohexyl (meth) acrylate, 10-sulfodecyl (meth) acrylate, and 2- (meth) acrylamide. -2-methylpropanesulfonic acid and alkali metal salts thereof, alkaline earth metal salt amine salts, and the like.
These acidic group-containing radical polymerizable monomers other than these water-soluble acidic group-containing radical polymerizable monomers (A) may be used singly or in appropriate combination, among which 10- (meth) acryloxydecyl is used. Hydrogen phosphate, 4- (meth) acryloxyethyl trimellitic acid, 4- (meth) acryloxyethyl trimellitic anhydride and the like are preferable.

One or more of these water-soluble acidic group-containing radically polymerizable monomers can be arbitrarily selected and used, and the pH adjusting adhesive composition of the present invention can be used in combination within the range of a heterogeneous solution. The blending amount of these water-soluble acidic group-containing radical polymerizable monomers is 1 to 80% by weight, preferably 3% by weight, based on the total amount of the pH-adjusting adhesive composition of the present invention. -60% by weight, particularly preferably 5-30% by weight. If it is less than 1% by weight or more than 80% by weight, the adhesiveness is lowered.

One or more radically polymerizable monomers having these acidic groups can be arbitrarily selected and used by appropriately adding to the pH adjusting adhesive composition of the present invention. The blending amount is 1% by weight to 80% by weight, preferably 3% by weight to 60% by weight, particularly preferably 5% by weight, based on the total amount of the pH adjusting adhesive composition of the present invention. ~ 30% by weight. If it is less than 1% by weight or more than 80% by weight, the adhesiveness is lowered.

Water (B) used in the one-component adhesive composition of the present invention is water that is acceptable for medical use, and ion-exchanged water, purified water, and the like are used. These waters are expected to promote the ion dissociation of the acid group of the water-soluble acidic group-containing radical polymerizable monomer of the present invention, and to enhance the demineralization of the tooth and the penetration into the dentin. The blending amount is 1% by weight to 90% by weight, preferably 15% by weight to 70% by weight, particularly preferably 20% by weight, based on the total amount of the one-component adhesive composition of the present invention. % To 60% by weight. If it is less than 1% by weight or more than 90% by weight, the adhesiveness is lowered.

As the alkali added in advance to the pH-adjusting adhesive composition of the present invention, any alkali capable of adjusting the pH of the acidic solution can be used. For example, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, lithium carbonate, lithium hydrogen carbonate, etc., among which sodium hydroxide is particularly preferable.

The present invention is a pH-adjusting adhesive composition having a pH value adjusted by adding sodium hydroxide in advance of pH 2.6 to 3.5, particularly preferably pH 2.8 to 3.2. A pH-adjusting adhesive composition that is a “homogeneous solution” or a “heterogeneous solution” that may be separated into layers.

The radical polymerizable monomer that may be added to the present invention is an aliphatic and aromatic monofunctional or polyfunctional radical polymerizable monomer, which is used in the dental field and general industry. A monomer, oligomer, and prepolymer having an unsaturated double bond can be selected and used. Moreover, the polymeric monomer which has a sulfur atom in a molecule | numerator, the polymeric monomer which has a fluoroalkyl group in a molecule | numerator, and the functional group which has a fluorine ion discharge | release capability can also be used.
Any one or more of these radically polymerizable monomers can be selected and added.

Specific examples of the radical polymerizable monomer include ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, hexamethylene glycol di (meth) acrylate, 2,2-bis {4- (meth) Acryloxypropoxyphenyl} propane; bisphenol A-diglycidyl (meth) acrylate, di (meth) acryloxyethyl-2,2,4-trimethylhexamethylenediurethane.
For example, one or more polymerization initiators can be arbitrarily selected from peroxides, α-diketones, (bis) acylphosphine oxides, coumarin compounds, and thioxanthone derivatives.
By using a plurality of these catalysts, excellent curing characteristics can be obtained without selecting a light source such as a halogen lamp, LED, or xenon lamp used in a commercially available dental photopolymerizer.

The peroxide is preferably selected from one or more of benzoyl peroxide, 4,4'-dichlorobenzoyl peroxide, and tert-butyl peroxymaleic acid. The α-diketone is preferably D, L-camphorquinone or benzyl. (Bis) acylphosphine oxides are preferably 2,4,6-trimethylbenzoylmethoxyphenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) acylphosphine oxide. The coumarin compounds are preferably 3,3'-carbonylbis (7-diethylaminocoumarin) and 3,3'-carbonylbis (7-dibutylaminocoumarin). The one-step type in which the thioxanthone derivative is 2-chlorothioxanthen-9-one is preferable.

Other photopolymerization initiators are water-soluble photopolymerization initiators such as 2,4,6-trimethylbenzoylphenylphosphine oxide sodium and 2-hydroxy-3- (3,4-dimethyl-9H-thioxanthene-2- (Iloxy) -N, N, N-trimethyl-1-propanaminium chloride can also be used.

Polymerization accelerators that may be added to the present invention include amines such as N, N-di (2-hydroxyethyl) -p-toluidine, 4-N, N-dimethylaminobenzoic acid ethyl ester, 5-butylbarbitur Acids, 1,3,5-trimethylbarbituric acid, 1-cyclohexyl-5-ethylbarbituric acid, 1-benzyl-5-phenylbarbituric acid and other barbituric acids, and di-n-octyltin dilaurate and di Organic tin compounds such as n-butyltin dilaurate and 2,4,6-tris (trichloromethyl) -1,3,5-triazine, 2- (p-methoxyphenyl) -4-bis (trichloromethyl) -1 A trihalomethyl group-substituted 1,3,5-triazine compound such as 1,3,5-triazine is preferable. .

The organic solvent that may be added to the present invention is preferably acetone and ethyl alcohol.

The fillers that may be added to the present invention are preferably ultrafine particle fillers, fluorine sustained-release fillers, polymers and silica fillers.

In order to adjust the mechanical strength, operability, applicability, and fluidity of the pH-adjusting adhesive composition of the present invention, a filler may be appropriately blended. Any filler that can be generally used in dentistry can be used. Particularly preferred are ultrafine fillers, fluorine sustained-release fillers, polymers and silica fillers.

Examples of the polymerization inhibitor contained for the purpose of preventing the gelation of the pH-adjusting adhesive composition of the present invention and stabilizing the shelf life include hydroquinone, hydroquinone monomethyl ether, butylated hydroxytoluene, etc., but hydroquinone monomethyl ether And butylated hydroxytoluene is suitable.

That is, the pH-adjusting adhesive composition of the present invention comprises a water-insoluble acidic group-containing radical polymerizable monomer, a radical polymerizable monomer that does not contain an acidic group in the molecule, a polymerization initiator, if necessary. A filler, an organic solvent, a modifier, a thickener, a dye, and a pigment can be appropriately selected and added.
As these agents, those used in the dental field and general industrial industry can be used.

The pH-adjusting adhesive composition of the present invention is used as a one-component cell etching primer, a one-component one-step type bonding material as an embodiment, and is used as a dental composite resin, low-viscosity composite lens, resin cement, It can be used as a set with resin-modified glass ionomer cement, fisher sealant, orthodontic adhesive, tooth surface coating material, opaque material and the like.

Next, the present invention will be specifically described with reference to examples and comparative examples. In addition, this invention is not limited to these Examples at all.

Abbreviations of the compounds used in the examples of the present invention are shown below.
6-MHPA: 6-methacryloxyhexyl phosphonoacetate
6-MHPP: 6-methacryloxyhexyl-3-phosphonopropionate
4-MET: 4-Methacryloxyethyl trimellitic acid
4-AET: 4-Acryloxyethyl trimellitic acid
Bis-GMA: Bisphenol A-diglycidyl methacrylate,
UDMA: Dimethacryloxyethyl-2,2,4-trimethylhexamethylenediurethane
TEGDMA: Triethylene glycol dimethacrylate
GDMA: 2-hydroxy-1,3-dimethacryloyloxypropane
CQ: Camphorquinone
TBPO: 2,4,6-Trimethylbenzoyldiphenylphosphine oxide
4-MABE: ethyl 4-dimethylaminobenzoate
BPBA: 1-benzyl-5-phenylbarbituric acid
R-972: Ultrafine silica filler (average particle size: 0.18 μm)
MeHQ: Hydroquinone monomethyl ether

Example 1 and Comparative Examples 1-3
In carrying out the pH adjusting adhesive composition of the present invention in the form of a one-step type one-part dental bonding material, 6-MHPA (6.0 parts by weight), 4-MET (6.0 parts by weight), distilled water (34.0 Parts by weight), Bis-GMA (12.8 parts by weight), TEGDMA (8.5 parts by weight), CQ (0.6 parts by weight), 4-MABE (0.4 parts by weight), R-972 (1.2 parts by weight), acetone (6.0 parts by weight) ), And MeHQ were added to the total amount of radical polymerizable monomers by 2000 ppm and mixed with a mixer. Here, the liquid is prepared by adding dropwise a 0.1N or 1.0N aqueous sodium hydroxide solution to a mixture consisting of a radical polymerizable monomer having an acidic group to a polymerization inhibitor until the pH value becomes suitable while measuring pH, Finally, water, a photopolymerization initiator and a photopolymerization accelerator were added and mixed in a dark room to prepare a pH adjusted adhesive composition having a pH value of 3.0. For comparison, adhesive compositions having pH values of 2.5 and 2.1 were prepared. A black container made of polyethylene was filled with 5 g of these adhesive compositions.

In testing the shelf life of the one-component, one-step type pH adjusting adhesive composition prepared as described above, a forced life promotion test was conducted by placing these adhesive compositions in a 50 ° C. incubator for a certain period of time. . Using the adhesive composition aged at each period, a shear adhesion test of tooth enamel and dentin with a composite resin was performed.

[Shear adhesion test]
The tooth quality was changed to human teeth using freshly extracted bovine anterior teeth, the roots were deleted and the pulp removed, and then embedded in epoxy resin. The lip enamel and dentin of the bovine teeth were polished with water-resistant polishing paper No. 80 under water injection and then polished with No. 600 under water injection. The polished tooth surface was dried with compressed air containing no oil, and a double-sided tape with a hole having a diameter of 4 mm was attached thereto to define an adhesive surface. Next, after a bottle containing the one-component one-step type pH adjusting adhesive composition is shaken lightly, it is dropped on the eye plate, applied to the adhesion regulating surface with a microbrush, and treated to rub for 10 seconds. A weak compressed air was blown for 5 seconds to evaporate the volatile components, and the bonding material was spread thinly on the tooth surface. Subsequently, the sample was irradiated for 10 seconds with Matsukaze Grip Light II [manufactured by Matsukaze Corporation]. Thereafter, a plastic mold having a diameter of 4 mm and a height of 2 mm was fixed to the adhesion regulating face frame, and a photopolymerizable composite resin “Beauty Fill” [manufactured by Matsukaze Co., Ltd.] was filled in the mold. Next, air was blocked with a cover glass, and light irradiation was performed with a pine-style grip light II for 30 seconds to photocur the composite resin, and then the mold was removed to prepare an adhesion test body. After immersion in distilled water at 37 ° C. for 24 hours, the specimen is set on a jig for shear bond strength and shear bonded at a crosshead speed of 1 mm / min using an Instron universal testing machine (Instron 5567, Instron). The strength was measured and the average value of n = 7 was obtained. The results of the adhesion test are shown in Table 1.

As is apparent from Table 1, the adhesive strength after 50 days at 50 ° C. of the pH adjusting adhesive composition (Example 1) adjusted to pH 3.0 of the present invention is the adhesion immediately after preparation without significant adhesion deterioration. Maintained strength. On the other hand, the adhesive compositions adjusted to pH 2.5 and 2.1 (Comparative Examples 1 and 2) have a high bond strength immediately after that, but a significantly low bond strength after 50 days at 50 ° C., especially for enamel bonds. It came off (0 MPa). As described above, even when the adhesive composition is almost similar, the adhesive composition having a pH of 2.5 or less showed a significantly poor shelf life.

Example 2 and Comparative Example 3
In carrying out the pH adjusting adhesive composition of the present invention in the form of a one-step one-part dental bonding material, 6-MHPA (3.6 parts by weight), 4-MET (6.0 parts by weight), distilled water (34.0 Parts by weight), Bis-GMA (12.8 parts by weight), TEGDMA (8.5 parts by weight), CQ (0.6 parts by weight), 4-MABE (0.4 parts by weight), R-972 (1.2 parts by weight), acetone (6.0 parts by weight) ), And MeHQ was prepared by adding 2000 ppm to the total amount of radically polymerizable monomers and mixing with a mixer, and adding an aqueous sodium hydroxide solution in the same manner as in the examples to adjust the pH to 3.0. Was prepared. As a comparison, an adhesive composition having a pH value of 2.1 was prepared. Both adhesive compositions 5 g were filled into a black container made of polyethylene.

In testing the shelf life of the one-component one-step type pH adjusting adhesive composition thus prepared, a 50 ° C. forced life promotion test was conducted according to Example 1, and the adhesive composition aged in each period. A shear adhesion test was performed using the object. The results are shown in Table 2.

As is apparent from Table 2, the adhesive strength of the pH-adjusted adhesive composition (Example 2) adjusted to pH 3.0 of the present invention after 50 days at 42 ° C. is the adhesion immediately after preparation without significant adhesion deterioration. Maintained strength. On the other hand, in the adhesive composition adjusted to pH 2.1 (Comparative Example 3), the adhesive strength immediately after 50 days at 50 ° C. is remarkably low although the adhesive strength is high immediately, especially 20.8 MPa → 1.5 for enamel adhesive. I came to MPa. As described above, even when the adhesive composition is almost similar, the adhesive composition having a pH of 2.5 or less showed a significantly poor shelf life.

Example 3 and Comparative Example 4
In carrying out the pH-adjusting adhesive composition of the present invention in the form of a one-step one-part dental bonding material, 6-MHPP (3.6 parts by weight), 4-MET (6.0 parts by weight), distilled water (34.0 Parts by weight), Bis-GMA (12.8 parts by weight), TEGDMA (8.5 parts by weight), TBPO (0.8 parts by weight), CQ (0.5 parts by weight), 4-MABE (0.4 parts by weight), R-972 (1.2 parts by weight) ), Acetone (6.0 parts by weight), and MeHQ were prepared by adding 2000 ppm to the total amount of the radical polymerizable monomers and mixing with a mixer. A pH adjusting adhesive composition was prepared. As a comparison, an adhesive composition having a pH value of 2.1 was prepared. Both adhesive compositions 5 g were filled into a black container made of polyethylene.

In testing the shelf life of the prepared one-component one-step type pH adjusting adhesive composition, a 50 ° C. forced life promotion test was conducted according to Example 1, and the adhesive composition aged at each period was used. Then, a shear adhesion test was performed. The results are shown in Table 3.

The adhesive strength of the pH-adjusted adhesive composition (Example 3) adjusted to pH 3.0 of the present invention up to 42 days after 50 ° C. maintained the adhesive strength immediately after preparation without significant reduction in adhesion. In contrast, in the adhesive composition adjusted to pH 2.1 (Comparative Example 4), the adhesive strength immediately after 50 days at 50 ° C. was extremely low although the adhesive strength was high immediately after.

Example 4 and Comparative Example 5
In carrying out the pH adjusting adhesive composition of the present invention in the form of a one-component self-etching primer, 6-MHPA (6.0 parts by weight), 4-AET (6.0 parts by weight), distilled water (49.0 parts by weight), Bis -Radical polymerization of GMA (3.0 parts by weight), TEGDMA (2 parts by weight), GDMA (5 parts by weight), CQ (0.6 parts by weight), 4-MABE (0.4 parts by weight), acetone (35 parts by weight), and MeHQ The mixture was prepared by adding 2000 ppm to the total amount of the monomer and mixing with a mixer, and a sodium hydroxide aqueous solution was added dropwise in the same manner as in the Example to prepare a one-component self-etching primer having a pH value of 3.0. As a comparison, a composition having a pH value of 2.1 was prepared.

The prepared pH-adjusted one-part self-etching primer was subjected to a shear adhesion test using an adhesive composition whose life was accelerated by 50 ° C. according to Example 1. Here, in the shear adhesion test, the tooth surface was treated with a one-component self-etching primer for 10 seconds by replacing with the one-component adhesive composition of Example 1, and then impervafluorobond bonding material (Matsukaze Corporation). This was carried out in the same manner as in Example 1 except that the photopolymerization was carried out for 10 seconds.

As a result, as Example 4, the pH-adjusted one-component self-etching primer adjusted to pH 3.0 was (1) the adhesive strength (MPa) to enamel immediately after storage at 50 ° C. for 42 days: 22.5, 21 days later: 18.8, 42 days later: 17.2, (2) Dentin bond strength (MPa) was 23.8, 21 days later: 21.5, 42 days later: 18.8. The bond strength immediately after was maintained.
On the other hand, as Comparative Example 5, the adhesive strength (MPa) to (3) enamel of the one-component self-etching primer of pH 2.1 until storage at 50 ° C. for 42 days was immediately after: 21.7, after 21 days: 14.6, 42 days later: 8.2, (4) Adhesion strength to dentin (MPa) was 22.5, 21 days later: 16.2 and 42 days later: 9.4. The strength was extremely low.

Example 5 and Comparative Example 6
The adhesive compositions of Examples 5 and 6 were prepared in the same manner as in Examples 3 and 4 except that Bis-GMA in the adhesive compositions of Example 3 and Comparative Example 4 was replaced with UDMA. . A metal-to-tooth shear adhesion test with a resin cement was carried out using both adhesive compositions whose forced life was accelerated until 42 days after 50 ° C. according to Example 3. According to Example 3, it was applied to the enamel or dentin adhesive surface and then photopolymerized to perform an adhesion treatment. Further, an aluminum oxide powder was sprayed onto the adhesive surface of a stainless steel rod (diameter 5 mm, length 12 mm) to perform sandblasting. Next, impregnating dental resin cement (manufactured by Matsukaze Co., Ltd.) in accordance with the instructions, kneading the powder and liquid materials with a spatula, and finishing the above-mentioned adhesive treatment with the kneaded mud interposed A stainless steel rod was joined to the tooth surface of the steel plate, a load of 200 g was applied, and the kneaded mud protruding from the adhesive interface was removed with a blade. Subsequently, the adhesion interface was irradiated with light for 20 seconds from an oblique direction using Matsukaze Grip Light II [manufactured by Matsukaze Co., Ltd.]. Thereafter, in the shear bond strength test, the specimen was immersed in distilled water at 37 ° C. for 24 hours and then measured using an Instron universal testing machine (Instron 5567, Instron) at a crosshead speed of 1 mm / min. The average value of = 7 was obtained.

[Results] The adhesive strength of the tooth-stainless steel rod up to 42 days after 50 ° C. of the pH adjusting adhesive composition is shown below.
(1) Enamel-Strength of stainless steel rod (MPa)
Example 5 (pH 3.0): Immediately: 20.8, 21 days later: 16.2, 42 days: 14.6
Comparative Example 6 (pH 2.1): Immediately: 20.1, 21 days later: 13.2, 42 days: 3.3
(2) Dentin-stainless steel bond strength (MPa)
Example 5 (pH 3.0): Immediately: 19.5, 21 days later: 15.3, 42 days: 13.8
Comparative Example 6 (pH 2.1): Immediately: 19.8, 21 days later: 12.2, 42 days: 8.5
From the above results, the pH-adjusted adhesive composition adjusted to pH 3.0 maintained the adhesive strength immediately after preparation without a significant decrease in adhesion, whereas the pH 2.1 adhesive composition maintained the adhesive strength immediately after preparation. However, the bond strength after 42 days at 50 ° C. was extremely low.

The pH-adjusting adhesive composition of the present invention can be used in the fields of adhesives, paints, lacquers and the like in the general industrial field in order to maintain the shelf life of the adhesive composition and maintain the adhesive performance.

Claims (2)

(A) 6- (meth) acryloxyhexyl-3-phosphonoacetate or 6- (meth) acryloxyhexyl-3, which is a water-soluble acidic group-containing radical polymerizable monomer that is soluble in water by 5% or more -3 wt% to 60 wt% of phosphonopropionate, (B) 15 wt% to 70 wt% of water , (C) a radical polymerizable monomer other than the acidic group-containing radical polymerizable monomer, ( D) An adhesive composition containing a polymerization initiator and (E) an organic solvent, wherein an adhesive is added to the adhesive composition to adjust the pH value to 2.6 to 3.5. A pH adjustment adhesive composition for a one-step one-part dental bonding material, characterized in that the shelf life of the adhesive composition is maintained. 10- (meth) acryloyloxydecyl hydrogen phosphate, wherein the acidic group-containing radical polymerizable monomer (F) other than the water-soluble acidic group-containing radical polymerizable monomer (A) that dissolves in water by 5% or more, The pH-adjusting adhesive composition according to claim 1, which is 4- (meth) acryloxyethyl trimellitic acid or 4- (meth) acryloxyethyl trimellitic anhydride.