JP3466320B2 - Polymeric curable resin surface coating - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface coating agent for a polymerization curable resin which is susceptible to polymerization inhibition by oxygen in the air.

[0002]

2. Description of the Related Art In recent years, it has been generalized in the field of dental treatment to use a curable resin having excellent aesthetics and operability for repairing a tooth defect portion, and a relatively small defect after the carious portion is removed. Polymerization curable resins are used not only for direct filling of a tooth but also for production of restorations for prosthetic restorations such as inlays, onlays and crowns used for restoration of large defects. Further, a polymerization curable resin is also used for a resin adhesive (cement). Dental polymerization curable resin is usually a composition comprising a (meth) acrylic monomer, a radical polymerization initiator and a filler. After shaping the composition into a desired shape, the monomer is polymerized and cured. By doing so, the tooth defect part is repaired or a therapeutic restoration is prepared.

When radically polymerizing a (meth) acrylic monomer in air, the polymerization reaction is hindered by oxygen in the air, and an unpolymerized layer in which the monomer is not polymerized may be formed on the surface of the cured product. In addition, the degree of polymerization near the surface layer of the cured product may be lower than the degree of polymerization inside the cured product that is sufficiently cured without being inhibited by oxygen. As a result, there was a problem that the lubricity of the obtained cured product surface was poor, the cured product was discolored after mounting in the oral cavity, and the mechanical strength of the surface layer portion of the cured product was reduced. . Therefore, many proposals have been made to eliminate the inhibition of polymerization caused by oxygen in the air. Among them, a general method is a method of applying a paste-like composition to the surface of the resin in advance before initiating the polymerization of the monomer to shield the surface of the resin from contact with oxygen in the air.

As such a method, for example, Japanese Patent Laid-Open No.
-100505 discloses that a mixture of a water-soluble organic compound containing a surfactant (polyvinylpyrrolidone, polyvinyl alcohol, etc.) and water is applied to the surface of a shaped article of a photopolymerizable resin, and light is passed through a layer of the mixture. Irradiation, the method of curing the polymerizable resin, JP-A-58-201628, in JP-A-58-201628, a masking agent consisting of polyvinyl alcohol or polyethylene glycol and water is applied to the preform of the curable resin, and then the curable resin is applied. A method of polymerizing and curing is disclosed in JP-A-59-36604, and a method of using a masking agent for molding a curable resin containing polyvinyl alcohol, water and an organic peroxide as main components is disclosed in JP-B-63-37082. The publication discloses a surface obtained by mixing polyethylene glycol having an average molecular weight of 150 to 420 and polyethylene glycol having an average molecular weight of 1800 to 20000 in a paste form. As a method of using a covering agent, JP-A-4-169510 discloses a method of using an oxygen blocker composed of glycerin or its oligomer and a surfactant, and JP-A-62-5. Describes a method of using a paste-like surface coating composition containing 10 to 50% by weight of highly dispersible hydrophilic silica (silicon dioxide).

[0005]

In the above methods (1) to (3), the composition applied to the surface of the resin (hereinafter these are abbreviated as oxygen blockers) has poor shaping properties, and the oxygen blocker is uniformly distributed on the resin surface. It is difficult to apply, the shape retention of the composition is also insufficient, the oxygen blocker flows after being applied to the resin surface, and the thickness of the oxygen blocker layer formed on the resin surface is There was a problem that it became partially thin. On the other hand, the composition described above is intended to have a moderate viscosity in the surface coating composition to improve the shapeability, but the shape retention of the composition is still not good. Moreover, there is a problem in operability such that the paste is sticky and a thread is pulled when the paste is applied to the resin surface (spinability).

Therefore, the present invention relates to a surface coating agent which is applied to a resin surface in advance when the polymerization curable resin is cured to shield the resin surface from contact with oxygen in the air. An object of the present invention is to provide a surface coating agent for a polymerization curable resin, which has good shape and shape retention and is excellent in operability.

[0007]

According to the present invention, the above-mentioned problems are solved by: 0.1 part of a fine powder having a hydrophobic surface with respect to 100 parts by weight of a hydrophilic liquid having a boiling point of 120 ° C. or higher at 760 mmHg. It is achieved by providing a surface-coating agent for a polymerization-curable resin, which is dispersed in an amount of 10 to 10 parts by weight.

The term "polymerizable curable resin" as used in the present invention means acrylic acid monomers such as (meth) acrylic acid esters and (meth) acrylamides, vinyl ethers, styrene derivatives, esters of crotonic acid and cinnamic acid with alcohols. It refers to a composition containing a radical polymerizable monomer such as a class and a thermal polymerization initiator, a polymerization initiator such as a photopolymerization initiator as a main component, even if containing a filler such as silica, alumina Good.

In the present invention, a fine powder having a hydrophobic surface is dispersed in a hydrophilic liquid to form a surface coating agent having good shapeability and shape retention and excellent operability. Is important in obtaining. In the present invention, the fine powder having a hydrophobic surface means a fine powder having a contact angle with water in the range of 30 to 180 degrees.

In the present invention, the value measured by the following method is defined as the contact angle between fine powder and water. That is, 1 g of fine powder was charged into a mold having a hole with a diameter of 1 cm, and the powder was pressed with a press machine at a pressure of 50 kg / cm ² for 10 minutes, and distilled water was placed on the horizontal surface of the obtained molded body. Dropping is performed, and the contact angle between the horizontal surface and the water droplet formed on the horizontal surface is measured. The larger the contact angle, the greater the degree of hydrophobicity.

The fine powder in the present invention may be formed of either an organic substance or an inorganic substance. In the case of an organic substance, for example, polymers made of various (meth) acrylate-based monomers such as polymethyl (meth) acrylate, powders of organic resins such as polyvinyl chloride, etc. are preferably used. Further, in the case of an inorganic substance, for example, silica, alumina, zirconia, titanium oxide, calcium carbonate, various glasses, ceramics and the like are preferably used. Further, for example, a powder obtained by condensing a hydrolysis product of an alkoxysilane substituted with an alkyl group, or an organic-inorganic composite material in which inorganic fine particles are dispersed in the organic resin matrix to form a sea-island structure It may be powder.

When the surface of the fine powder is hydrophobic, that is, when the contact angle between the fine powder and water is in the range of 30 to 180 degrees, the fine powder can be used as it is in the present invention. However, when the contact angle with water is not within the above range and the surface is hydrophilic fine powder, it is necessary to treat the surface of the fine powder with a surface treating agent to make the surface hydrophobic. is there. As such a surface treatment agent, a silane coupling agent is preferably used, for example, trimethylchlorosilane, methyltrichlorosilane, ethyltrichlorosilane, phenyltrichlorosilane, octadecyldimethylchlorosilane, n-propyltrimethoxysilane, dodecyltrimethoxysilane, Examples include octyltrimethoxysilane, octadecyltrimethoxysilane, hexamethyldisilazane, 3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, and perfluoroalkylsilane. Further, titanium-based coupling agents such as isopropyltriisostearoyl titanate, organic phosphorus compounds such as mono- or diesters of lauryl alcohol and phosphoric acid, and fatty acids such as stearic acid can also be used as the surface treatment agent. Such surface treatment agents may be used in combination of two or more kinds. Also,
It is also possible to make the surface of the fine powder hydrophobic by coating the surface of the fine powder with a silicone polymer such as polydimethylsiloxane. It is preferable that the fine powder having a hydrophobic surface is also subjected to a surface treatment to adjust the degree of hydrophobicity, because a surface coating agent having more suitable paste properties can be obtained.

The above surface treatment is carried out by a known method such as immersing fine powder in a solution of the surface treatment agent. Such surface treatment is usually performed before the fine powder is dispersed in the hydrophilic liquid, but the fine powder not subjected to the surface treatment is dispersed in the hydrophilic liquid, and then the surface treatment agent is added. It may be added, or fine powder may be added to the mixed liquid of the hydrophilic liquid and the surface treatment agent. The amount of the surface treatment agent to be used increases as the specific surface area of the fine powder increases, but is usually in the range of 0.1 to 100 parts by weight with respect to 100 parts by weight of the fine powder.

The fine powder used in the present invention has a specific surface area of 3
It is preferably 0 m ² / g or more and the average particle diameter is 0.1 μm or less. When the specific surface area and the average particle diameter are within these ranges, it is possible to obtain a surface coating agent which is particularly excellent in shapeability and shape-retaining property and which is small in stringiness and excellent in operability. Fine powder has a specific surface area of 50 to 500 m
² / g and an average particle diameter of 0.05 to 0.001 μm are more preferable.

In the present invention, the hydrophilic liquid is 7
It is necessary to use a liquid having a boiling point of 120 ° C. or higher at 60 mmHg. Boiling point at 760 mmHg is 1
When a liquid having a temperature of less than 20 ° C. is used, the surface coating agent is applied to the surface of the resin and then the liquid is quickly dried and disappears. Therefore, the resin surface may come into contact with oxygen in the air during polymerization of the resin. And the oxygen barrier effect is lost.

The hydrophilic liquid referred to in the present invention is 2
Solubility in water at 5 ° C is 10% by weight (10 g /
It means a liquid of 100 ml or more of water.

Hydrophilic liquids having a boiling point and a solubility in water within the above ranges include, for example, ethylene glycol, glycerin, diglycerin, triglycerin,
Examples thereof include polyethylene glycol, propanediol, polypropylene glycol, polyethylene glycol monoalkyl ether, 2-methyl-1,2,4-butanetriol and the like. Further, two or more kinds of hydrophilic liquids may be mixed and used. Among these, when a compound having two or more hydroxyl groups in one molecule such as glycerin and ethylene glycol is used, it is possible to obtain a surface coating agent having good shapeability and shape retention, and low stringiness. It is preferable because it is possible.

As the hydrophilic liquid used in the present invention, a compound having a radical-polymerizable double bond in the molecule is not preferable. When a compound having a radical-polymerizable double bond is used as a hydrophilic liquid, the monomer component that constitutes the resin and the liquid component that constitutes the surface coating agent are copolymerized during the curing of the polymerization-curable resin. This is because it becomes difficult to remove the coating agent from the surface of the cured product. Further, a compound that can serve as a solvent for the monomer component constituting the polymerization-curable resin is not preferable as the hydrophilic liquid in the present invention. For example, constructing a dental resin (meta)
For acrylate-based monomers, such compounds include dimethylformamide (DMF), dimethylacetamide (DMA), dimethylsulfoxide (DMSO), and butylcellosolve. When such a compound that serves as a solvent for the monomer component constituting the polymerization-curable resin is used as a hydrophilic liquid, the monomer component of the polymerization-curable resin is dissolved, and the surface of the resulting cured product becomes rough or cloudy. I will.

In the surface coating agent of the present invention, the amount of 760 mmHg, such as water or ethanol, is adjusted in order to adjust the shapeability and shape retention in an amount not exceeding 20% by weight based on the total weight of the coating agent. A solvent having a boiling point of 120 ° C. or less can also be added.

The blending amount of the fine powder in the surface coating agent of the present invention varies depending on the degree of hydrophobicity of the surface of the fine powder, the kind of the hydrophilic liquid, the particle size of the fine powder, etc., but is usually the hydrophilic liquid. It is in the range of 0.1 to 10 parts by weight, preferably in the range of 1 to 8 parts by weight, relative to 100 parts by weight. If the amount of the fine powder is less than 0.1 part by weight with respect to the hydrophilic liquid, the surface coating agent obtained has insufficient shapeability and shape retention, and the amount of the fine powder is hydrophilic. If the amount is more than 10 parts by weight with respect to the liquid, the obtained surface coating agent becomes hard and is difficult to apply, which is not preferable.

In the surface coating agent of the present invention, various surfactants are preferably blended for the purpose of improving compatibility with the resin surface when the surface coating agent is applied to the resin surface. Examples of the surfactant include alkylbenzene sulfonate, α-olefin sulfonate, alkane sulfonate, quaternary ammonium salt containing a long chain alkyl group, fatty acid mono- or diethanolamide, fatty acid (poly) ethylene glycol ester or Ether, monofatty acid glycerin ester, fatty acid sorbitan ester, fatty acid sorbitan ester polyoxyethylene, alkylphenyl polyoxyethylene ether, N
Anionic, cationic, nonionic, amphoteric surfactants such as alkyl betaine derivatives and sulfobetaine derivatives can be used. These surfactants are usually used in the range of 0.01 to 20% by weight with respect to the hydrophilic liquid.

In the surface coating agent of the present invention, a reducing agent may be added for the purpose of reducing the concentration of dissolved oxygen in the surface coating agent. As such a reducing agent,
Aromatic sulfinates, sulfites, hyposulfites and the like can be mentioned, and among them, sodium benzenesulfinate, sodium toluenesulfinate, sodium sulfite and the like are preferable. A compound having a polymerization inhibiting action, such as phenol, inhibits the polymerization and curing of the polymerization curable resin and is therefore not preferable as the reducing agent. The amount of the reducing agent is usually 0.1 to 10 with respect to the hydrophilic liquid.
It is in the range of% by weight. Further, the reducing agent can be used in a dispersed state without being dissolved in the hydrophilic liquid.
Further, in the surface coating agent of the present invention, a colorant, a fragrance, an antiseptic, a stabilizer and the like can be added if necessary.

The surface coating agent of the present invention is obtained by mixing a hydrophilic liquid (dispersion medium) with a fine powder, and thoroughly kneading the mixture with a commonly used kneader such as a roll kneader or a twin mix. Is uniformly dispersed in a dispersion medium to prepare a paste-like composition. The obtained surface coating agent is usually subjected to defoaming treatment under reduced pressure. The surface coating agent thus obtained is preferably stored in a container made of a material that does not easily transmit oxygen.

The surface coating agent of the present invention is usually used in the following procedure. For example, in the case of preparing a photo-curing hard resin front crown, a polymerization-curable resin is built up on a metal frame for a front crown that has been prepared in advance, and then the surface coating agent of the present invention is thinly applied to the resin surface. It is applied with a brush and then irradiated with light to polymerize and cure the resin. Further, after the polymerization curable resin is built up, the surface coating agent of the present invention is applied to the surface of the resin cured product obtained by polymerizing and curing it by irradiating light, and further irradiating light again to cure the resin. It is also possible to polymerize the surface of the object. Further, in order to increase the degree of polymerization of the cured resin, it is possible to carry out heat treatment after polymerization and curing by light irradiation. Since the surface coating agent of the present invention is excellent in shape retention, the surface coating agent applied to the surface of the resin does not flow even after such heat treatment, and the shape at the time of application is maintained as it is. After polymerizing and curing the resin, the surface coating agent of the present invention is, for example,
It is removed from the surface of the cured resin by a means such as wiping with a cloth or paper or washing with water. Further, if necessary, the cured resin is subjected to shape modification by grinding, and the desired hard resin front crown is completed. Further, the surface coating agent of the present invention is also used in the same procedure as above when polymerizing and curing the polymerizing curable resin by heat or chemical polymerization.

[0025]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 As a hydrophilic liquid, ethylene glycol (760 mmH
(boiling point 197 ° C. g, dissolved at an arbitrary ratio in water at 25 ° C.) was used. Polyoxyethylene sorbitan monolaurate [manufactured by ICI, Tween 2 as a surfactant] in 100 parts by weight of ethylene glycol
0 (registered trademark)] was added as a dispersion medium. On the other hand, a mixture of 100 parts by weight of silica fine powder (specific surface area 130 m ² / g, average particle size 0.016 μm, Aerosil 130 manufactured by Nippon Aerosil Co., Ltd., 5 parts by weight of hexamethyldisilazane and 1000 parts by weight of toluene) was refluxed with toluene. The reaction mixture was heated at room temperature for 2 hours and the toluene was distilled off under reduced pressure and then under vacuum at 130 ° C. for 24 hours.
After drying for an hour, a fine silica powder having a hydrophobic surface was obtained. The contact angle of this fine silica powder with water was 120 degrees. 5 parts by weight of such silica fine powder and the above dispersion medium 10
0.5 part by weight was kneaded to sufficiently disperse the silica fine powder, and then defoamed under vacuum to prepare a paste-like surface coating agent. With respect to the obtained surface coating agent, the spinnability of the paste, the shape retention of the paste, and the shapeability (consistency) of the paste were evaluated by the following methods. Further, the surface curability of the polymerization curable resin when the surface coating agent was used was evaluated. The results are summarized in Table 1.

(1) Spinnability of paste In an atmosphere of 25 ° C., a paste-like surface coating agent was added to have an inner diameter of 2
It is placed in a cylindrical container having a depth of 0 mm and a depth of 10 mm, and the surface of the paste is smoothed. A polycarbonate round bar having a diameter of 10 mm and a length of 20 mm is inserted into the paste from right above to a depth of 5 mm. After standing still for 30 seconds in this state, when the bar is pulled right above at a speed of 1 cm / sec, the paste causes stringing. The round bar was pulled up until the thread was cut, and the length of pulling up at that time was measured and used as an index of the spinnability of the paste. The longer the round bar is pulled up,
The spinnability of the paste is strong, the paste is sticky,
Operability is poor.

(2) Morphological Retention of Paste Under an atmosphere of 25 ° C., 0.5 cc of the surface coating agent was weighed with a syringe, and the composition was extruded on a glass plate and allowed to stand. The glass plate was placed vertically, and after 1 minute, the length of the surface coating agent flowing downward was measured and used as an index of shape retention. The smaller the flow length of the composition, the better the shape retention of the paste.

(3) Formability of paste (concentration) 0.5 cc of the surface coating agent was weighed with a syringe in an atmosphere of 25 ° C., and the composition was extruded on a glass flat plate in a substantially circular shape and allowed to stand. I put it. On such a surface coating,
When 40 g of a glass plate is placed, the composition is spread in a circle. The diameter of the spread composition was measured and used as an index of the shapeability of the paste. The lower the diameter of the spread composition, the harder the paste. To have good coatability, the paste is unsuitable if it is too hard or too soft. When the diameter of the spread composition is in the range of 10 to 30 mm, the operability during application is excellent.

(4) Curing property of polymerization curable resin surface (thickness of unpolymerized layer on the surface) A resin paste for enamel part of a hard resin for photo-curing crown "Ceseed" (registered trademark, manufactured by Kuraray Co., Ltd.), It was weighed on an aluminum plate [W ₁ (g)] and spread thin and flat in the shape of a disk having a diameter of 1 cm [surface area S (cm ² )].
A surface coating agent was applied to the surface of the resin with a brush, and the resin was cured by irradiating it with visible light for 1 minute with a light irradiator for dental technology (Morita Seisakusho, α-light). The surface of the obtained cured product was washed with acetone to remove the surface coating agent and the unpolymerized monomer in the resin, dried at room temperature, and weighed [W ₂ (g)]. This value was compared with the weight of the resin paste initially weighed to calculate the weight reduction [W ₁ -W ₂ (g)]. The weight loss corresponds to the weight of unpolymerized monomer in the resin. The thickness [h (μm)] of the surface unpolymerized layer was calculated from the weight loss, the surface area [S (cm ² )] and the resin density [d (g / cm ³ )] of the spread resin. Then, it was used as an index of the curability of the surface of the polymerization curable resin. The smaller the value of the thickness of the surface unpolymerized layer,
The surface of the polymerization curable resin is sufficiently hardened and the surface of the resin is shielded from oxygen in the air.

Comparative Example 1 The curability of the surface of the curable resin was evaluated in the same manner as in Example 1 without using the surface coating agent. The results are also shown in Table 1.

Examples 2 to 4 and Comparative Examples 2 and 3 In the same manner as in Example 1 except that the blending amount of the fine powder having a hydrophobic surface was set as shown in Table 1. A surface coating agent was prepared and evaluated in the same manner as in Example 1. The results are also shown in Table 1.

Comparative Examples 4 and 5 In Example 1, fine silica powder having a hydrophilic surface (Aerosil 130 manufactured by Nippon Aerosil Co., Ltd.) was used, and the compounding amounts thereof were as shown in Table 1. Aside from the above, a surface coating agent was prepared in the same manner as in Example 1, and the same evaluation as in Example 1 was performed. The results are also shown in Table 1. The contact angle of the fine silica powder used in this comparative example with water was 0 degree (no water droplet was formed).

[0034]

[Table 1]

Examples 5 and 6 and Comparative Examples 6 and 7 A surface coating agent was prepared in the same manner as in Example 1 except that the hydrophilic liquid described in Table 2 was used. The same evaluation as in Example 1 was performed. The results are summarized in Table 2.

[0036]

[Table 2]

Examples 7 to 13 A surface coating agent was prepared in the same manner as in Example 1 except that the fine powder shown in Table 3 was used as the fine powder. An evaluation was made. The results are shown in Table 3.
Are shown together.

[0038]

[Table 3]

Example 14 A composite resin "CR inlay" for curing a photopolymerization type crown in a inlay cavity of a plaster model in which a MOD inlay cavity of a molar tooth was formed based on an impression taken from the oral cavity. (Registered trademark, manufactured by Kuraray Co., Ltd.) was filled. The coating composition prepared in Example 1 was applied to the surface of the resin with a brush, and the resin was cured by irradiating with visible light for 1 minute with a light irradiator for dental laboratories (α-light, manufactured by Morita Manufacturing Co., Ltd.). It was Then, using a dental heating polymerization device (Kuraray, KL100), 100
Heat at 15 ° C for 15 minutes. During the above-mentioned polymerization by light and polymerization by heat, the applied surface coating agent did not flow and the resin surface was not exposed. Remove the cured product from the plaster model, wash with water, correct the form and polish
A good inlay restoration was obtained.

[0040]

INDUSTRIAL APPLICABILITY The surface coating agent of the present invention has excellent shapeability and shape-retaining property, can be easily applied uniformly on the resin surface, and the surface coating agent can be applied to the resin surface after application. Does not flow. Further, the paste does not cause stringing and is excellent in operability. The surface coating agent of the present invention is, for example, a filling composite resin, a dental prosthesis resin, a resin adhesive (cement), a pit fissure sealant, a denture base material, a surface lubricant, and a tooth surface coating. When the polymerization curable resin used as a material or the like is cured, the surface of the resin can be sufficiently shielded from oxygen in the air, and the surface of the cured product can be sufficiently cured.

Continuation of the front page (56) Reference JP-A 63-183904 (JP, A) JP-A 62-5 (JP, A) JP-A 59-134705 (JP, A) JP-A 7-421 (JP , A) JP 4-169510 (JP, A) JP 62-292865 (JP, A) JP 60-100505 (JP, A) JP 60-6731 (JP, A) JP 59-36604 (JP, A) JP 58-201628 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) A61K 6/00-6/10 C09D 7/12 C09D 201 / 00

Claims (2)

(57) [Claims] 1. The boiling point at 760 mmHg is 120 ° C.
A surface-curing agent for a polymerization-curable resin, wherein 0.1 to 10 parts by weight of fine powder having a hydrophobic surface is dispersed in 100 parts by weight of the above hydrophilic liquid. 2. The fine powder has a specific surface area of 30 m ² / g or more and an average particle diameter of 0.1 μm or less.
A surface coating agent for the polymerization-curable resin described.