JPH06237950A - Release agent - Google Patents

Abstract

PURPOSE:To obtain an excellent release property by incorporating water and film formable clay ore into a release material to be applied on a gypsum pattern at the time of forming repair parts for dental purposes and preparing the release material in such a manner that the material has the thixotropic property to develop a flow property when the material is shaken. CONSTITUTION:This release agent consists of water and the film formable clay ore insoluble in water and the compsn. has the thixotropic property. Namely, the thixotropic property is released and the flow property is exhibited when a container contg. such compsn. is shaken. The thixotropic property is developed again within 10 seconds and the flow property is lost when the compsn. is rested still. Synthetic smectite and synthetic hectorite are preferably used in terms of good film formability and the rapid development of the powerful thixotropic property as the film formable clay ore. The film formable clay ore is compounded in a ratio of >=1wt.% to 15wt.% in the compsn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to dental treatment,
By polymerizing the polymerizable resin on the gypsum model that duplicated the morphology of the affected area, and applying it on the gypsum model to make repair parts in the shape necessary for use in repairing tooth defects, etc. More specifically, the present invention relates to a mold release material that aims to facilitate mold release of a cured resin product.

[0002] In dental treatment, after taking an impression of an affected area requiring treatment, and using the plaster to make a model in which the shape of the affected area is reproduced, the patient restores normal functions on the model. In some cases, the necessary form is applied to a polymerizable dental resin, and then a cured product obtained by polymerizing the resin is adhered to the affected area with a dental adhesive for treatment. In particular, the present invention relates to a release material used in such a treatment method.

[0003]

2. Description of the Related Art Conventionally, wax-like materials such as paraffin and stearic acid derivatives, or aqueous solutions of sodium alginate have been used as release agents for releasing gypsum models from resins. Also, an aqueous solution of poly (meth) acrylic acid and its salt (JP-A-49-9)
No. 4587), using silicone rubber (Japanese Patent Laid-Open No. Sho 6-62)
No. 1-134305) was proposed.

However, the conventionally used wax-like mold release material has too high a consistency and the gypsum model mold release material layer becomes too thick, and even if it is applied too much, it is difficult to correct it, and thus uneven coating is applied. However, there is a problem in shape reproducibility of a resin cured product formed by using a gypsum mold coated with this mold release material. In addition, a mold release material is always adhered to the surface of the resin cured on a mold coated with such a mold release material. However, when this resin is bonded to the affected area with a dental adhesive, this mold release material is used. Acts as "dirt". From this point of view, it is not preferable that wax such as paraffin adheres to the surface of the resin, because it will interfere with the next bonding step.

Further, with respect to an alginate-based release agent, the separation performance is insufficient, the viscosity of the release agent is too high, and uneven coating is likely to occur, and further the storage conditions of the release agent are poor. There was a problem such as deterioration. In addition, polyacrylic acid type mold release materials are too well compatible with dental resins and have poor separation performance, and silicone mold release materials have a small amount of silicone adhering to the surface of the cured resin as the next step. There was a problem that it interfered with.

[0006] Gypsum is a porous material having a rough surface, having a structure in which acicular crystals of calcium sulfate hydrate having a length of several tens of microns are randomly stacked. When a fluid resin paste of a polymerizable resin is placed on a model made of such a material and polymerized, the interlocking action occurs due to polymerization after the paste penetrates into the minute gaps on the plaster surface. It will prevent the resin from being taken out from the plaster mold. It is thought that if the pores on the surface of gypsum are filled with a mold release material, the mold release between the gypsum mold and the resin will be good, but simply filling only the pores is not effective enough. . In order to fully exert the effect of the release agent, it is necessary to use the release agent in a slightly excessive amount so as to form a thin layer so as to increase the smoothness of the plaster surface.

In order to solve these problems, the inventor of the present invention has found that a release material composed of an inorganic powder which is hardly soluble or insoluble in water, a water-soluble alcohol compound, and water (Japanese Patent Application No.
No. 2-294825). The reason why we proposed such a slurry is that the solution type mold release agent penetrates the solution into the porous gypsum, the amount of the mold release agent remaining on the surface is small, and the effect becomes uncertain, but if it is a slurry This is because the inorganic powder is surely left on the surface of the gypsum even if the liquid component is soaked.

The former is one in which spherical ultrafine silica gel or the like is dispersed in aqueous alcohol and forms a layer of silica gel on the gypsum when the aqueous alcohol soaks into the gypsum or evaporates. The essence is that the weaker this layer is, the less force is required for demolding. That is, it is considered that when the resin is released from the gypsum mold, the release material layer and the resin are in close contact with each other, and some adhesive force is exerted. If the release agent layer is weak when releasing the cured resin, it is easily torn, but a part of the release agent remains on the plaster and a part adheres to the resin surface. Therefore, this mold release material has excellent mold release performance, but there is adhesion of fine silica gel to the surface of the resin cured product that has come into contact with the mold release material, and it is necessary to wash it after mold release or to clean the surface by sandblasting. was there. That is, these release agents have not been sufficient to solve the problem of contaminating the resin surface in contact with them. Also, this mold release material is a product obtained by dispersing ultrafine silica gel or the like in aqueous alcohol, but the inorganic powder settles during storage, and the user had to shake the container to disperse the powder during use. .
Furthermore, this composition has a problem that the viscosity at the time of application is low and the release material easily sags and accumulates in the corners, which is not sufficient from the viewpoint of saving the user's trouble or commercialization.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems. That is, the object of the present invention is to facilitate the mold release when separating the dental resin cured product from the gypsum model, without contaminating the resin surface in contact with the mold release material, sedimentation of the components during storage of the composition It is to provide a mold release material having a basic performance of not having the above property, and further showing a special rheological property that is very easy to apply when using this.

[0010]

[Means for Solving the Problems] Among the above-mentioned objects, the purpose of a mold release material which is easy to mold release and does not contaminate the surface of the resin in contact with the mold release material is that it is not well compatible with dental resin and that plaster or This is achieved by a mold release material that is well compatible with water and has excellent film forming properties. Further, the purpose of a release agent which does not cause sedimentation of the composition during storage of the composition and further exhibits rheological properties that can be easily applied when it is used can be achieved by imparting thixotropy to the release agent composition. .

As a result of intensive investigations by the present inventors to solve this problem, certain clay minerals have very excellent film-forming properties.
It was found that the slurry in which it is dispersed has the ability to form a film when dried, and exhibits extremely strong thixotropy, and can impart ideal properties as a mold release material, resulting in the present invention.

This phenomenon of film-forming property is such that when a slurry containing a flaky substance such as mica is dried, the flakes are two-dimensionally oriented so that the leaves fall across the ground, and the overlapping portions of the flakes are slightly different. It seems that it forms a film because it has the adhesive force of. The film obtained by drying the slurry of the clay mineral can be handled as a film by tweezers etc. if it is not roughly handled, but such properties cannot be expected in the silica gel described above.

Also, it is known to impart thixotropic properties to dental compositions, and ultrafine spherical silica gel (Aerosil) has been used as a substance therefor. However, as described above, when used as a mold release agent, Aerosil has the property of contaminating the resin that comes into contact with it, which is not suitable for the purpose of the present invention. However, it has been found that some special clay minerals have thixotropic properties far exceeding those of Aerosil. As a mechanism for these substances to exhibit thixotropic properties, aerosil has a loose three-dimensional network structure due to hydrogen bonds, whereas flaky clay minerals are called card house structure, and while fine flakes come into contact with each other partly. It stacks in a random (no orientation at all) direction, forming a very bulky structure that resembles a house made of playing cards, and exhibits strong and quick thixotropy. Thus, a composition exhibiting a strong thixotropic property, the container containing the composition is shaken violently to give fluidity, the thixotropic property is recovered after a few seconds, and the composition flows down even when the container is turned upside down. There is nothing to do, and the sedimentation of the powder does not occur at all. In terms of usability, when applied with a brush or the like, the thixotropy is released and it shows fluidity, so it can be applied softly, but in a very short time (within 3 seconds in the most preferred mode) Thixotropy is expressed in the inside and no sagging (no fluidity)
That is a very convenient property. It is a property which cannot be expected from conventional Aerosil and the like that a substance exhibiting fluidity stops flowing within a very short time, which is a very valuable property in terms of usability.

The inorganic powder used in this mold release material must have film-forming properties and be capable of imparting strong thixotropy in a short time. These are found in the group of clay minerals, which need to be swellable in the solvent in which they are slurried. Such clay minerals are pyrophyllite,
Talc, minnesotaite, montmorillonite, beidellite, nontronite, saponite, hectorite, socolite, stevensite, bentonite, smectite, vermiculite, muscovite, paragolite,
Flogopite, biotite, margarite, clintnite, xanthophyllite, donpasite, sudow stone, pennite, clinochlore, loechite invergite,
Examples thereof include clay minerals such as chamosite, thuringite, lipidite, kaolinite, halloysite, dickite, nacrite, chrysotile, antigorite, amesite, clonsteadite, birchellin, and greenalite. These may be natural products or synthetic products, but the synthetic products exhibit extremely strong film-forming properties and thixotropy properties, and are low in impurities and excellent in color tone. Therefore, it is preferable. Among them, synthetic smectite and synthetic hectorite are particularly preferable in that they have both good film-forming properties and strong and rapid thixotropy. The optimum blending amount of such clay mineral varies depending on the type, but it is preferably 1% by weight or more and 10% by weight or less, more preferably 1% by weight or more and 5% by weight or more in the composition.
It is blended in a proportion of not more than wt%. The expression of the strong thixotropic property, which is a feature of the present invention, is insufficient in a compounding amount of less than this, and there is a problem in the ease of releasing the thixotropic property because the viscosity of the composition is too high in a compounding amount of more than this. Is.

Further, in actual clinical practice, it is widely practiced to impregnate a gypsum model with an organic compound called a gypsum hardening material to enhance the strength of gypsum. The gypsum model impregnated with this gypsum hardening material is widely used. Even if the release material is applied on the top surface, the release material may be repelled and cannot be applied uniformly. For release material,
A device that can be used for such a plaster model is necessary.

In order to solve this problem, it is preferable to use a lower alcohol, which is well compatible with water, as a dispersion medium for the separating material, mixed with water. As the lower alcohol, methanol, ethanol, propanol and butanol are preferable from the viewpoint of water solubility and volatility.

As described above, even when a gypsum hardening material is used by mixing a water-soluble lower alcohol as a solvent, a thin film of a release material can be formed on the surface of gypsum in a sufficiently short drying time. It is possible. However, depending on the type of the gypsum hardener, mixing of alcohol alone may cause problems in terms of uneven coating. In such a case, it is effective to allow a surfactant to coexist in the mold release material. The type of surfactant is not particularly limited, but in the case of swelling clay minerals, it is incorporated into the crystal structure depending on the ionic species contained in the surfactant, and as a result, the effect of the surfactant is diminished. Therefore, the applicability of the release agent may be reduced, so that it is necessary to use the combination carefully. Examples of the surfactant include alkylbenzene sulfonate, α-olefin sulfonate, alkane sulfonate, quaternary ammonium salt containing a long chain alkyl group, aliphatic mono-, 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-alkyl betaine type and sulfobetaine type surfactants, among them, octyl sodium sulfosuccinate, polyoxy Ethylene sorbitan monolaurate and the like are suitable. If desired, a colorant, a fragrance or the like can be added to the release material of the present invention.

As described above, the release material between the hardened resin and the gypsum can be prepared. The method of using this release material can be applied to the gypsum model by using a brush, or the nozzle can be used. It is also possible to spread thinly by releasing an appropriate amount of the mold release material from a container with a mark on a desired place and then air blowing.

Even more surprisingly, when the mold release material according to the present invention is used, it is possible to obtain a higher adhesive force than the conventional one when the obtained resin cured product is bonded with a dental adhesive. Become. The reason for this is not clear,
Compared with the conventional mold release material, the resin cured product obtained by using the mold release material of the present invention contributes to the fact that there is less fragile layer such as residual mold release material layer on the surface or less contamination that inhibits adhesion. It is thought that it is doing.

[0020]

As described above, the mold release material according to the present invention facilitates mold release when separating the hardened dental resin from the gypsum model. Furthermore, the resin surface that comes into contact with the mold release material is not contaminated, and a high adhesive force can be obtained when the obtained restoration component is bonded to the affected area with a dental adhesive. Further, due to its strong thixotropic property, the inorganic powder blended as a component does not settle. In addition, since the thixotropy property is restored within a very short period of time during its use, the coating film does not droop though it can be applied softly and thinly. As a result, there is little unevenness in the application of the mold release material, so that the resin cured product has excellent shape reproducibility.

[0021]

【Example】

Examples 1 and 2 and Comparative Example 1 In order to compare the short-time development of the thixotropy of clay minerals and the thixotropy of Aerosil, 2% of each powder was mixed in water, and a composition dispersed by ultrasonic waves was prepared. The composition is adjusted and the composition is put into a test tube having a diameter of 13 mm from the bottom 5
I put in each cm. Next, this test tube was shaken to confirm that the composition flowed, and after standing for 10 seconds, the test tube was turned upside down to test whether or not the composition flows from the bottom of the test tube. The results are shown in Table 1.

[Table 1]

Examples 3 to 4 and Comparative Example 2 Mold release materials having the compositions shown in Table 2 were prepared. All the compositions in the table are 0.3 g of powder and 9.7 g of dispersion medium mixed, and the aqueous ethanol is a 40% ethanol aqueous solution to which 2% of a surfactant (sodium octylsulfosuccinate) is added. did. When these mold release materials were used, the force required to separate the hardened dental resin from the gypsum model was measured, and at the same time, the adhesion of the mold release material to the resin surface was examined. Nissin Co., Ltd. educational inlay cavity model T
I-0C, 1 (A) (class II cavity) is the original type,
From this, an impression was taken using a silicon impression material. Next, cast an inlay cavity model made of gypsum obtained by pouring cemented gypsum into this impression type and hardening it,
This was air-dried for 1 day or more (hereinafter referred to as a plaster model) to prepare. Next, the mold release composition shown in Table 2 was applied to the cavity of the gypsum model and its periphery with a brush. Next, this cavity was filled with a composite resin for inlay (Clearfill CR inlay manufactured by Kuraray Co., Ltd.), and a wire with a diameter of 1 mm was planted in the center portion of the filled paste and then irradiated with light (40 seconds). , Cured resin.
To compare the performance of the mold release materials, the force required to release the cured resin by pulling the wire from the gypsum model was measured using the Instron universal test period and the crosshead speed of 2 m.
The measurement was performed under the condition of m / min. Whether or not the release material adhered was visually determined by whether or not the resin surface appeared white. The results are shown in Table 2.

[0023]

[Table 2]

Comparative Examples 3 to 9 In order to show how much the releasing force obtained by the measurement in Examples 3 to 5 is compared with the commercially available products, the same method as in Examples 3 to 5 was used. The release force was measured when several types of commercially available release materials were used. The test results are shown in Table 3.

[Table 3] As described above, the mold release material of the present invention can be released with an extremely small force equivalent to that of CR-SEP manufactured by Kuraray Co., Ltd., which was capable of releasing with the lowest force among the comparative examples.

Examples 5 and 6 and Comparative Examples 10 to 12 In order to examine the presence or absence of sedimentation of the components of the release agent, a composition was prepared by mixing 3 parts of inorganic powder with 97 parts of the aqueous alcohol used in Example 4, By leaving it at room temperature for 1 month,
The presence or absence of sedimentation of the inorganic powder was visually examined. Table 4 shows the types of inorganic components and the test results of each composition.

[Table 4]

Example 7 and Comparative Examples 13 and 14 In order to know the effect of the mold release material of the present invention on the adhesive force to the resin cured by contact with it, a resin cured using a typical mold release material was used. The adhesive strength of the dental adhesive to the resin cured by contact with the release material of the present invention was measured. The results are shown in Table 5. The adhesion test was performed by the following method. Place a cylindrical mold with an inner diameter of 10 mm and a depth of 6 mm on a newly prepared gypsum flat plate, fill it with a composite resin clear fill CR inlay for inlay, polymerize by irradiating with light, and have a diameter of 10 mm. 6
mm resin discs were made. At this time, the mold release materials shown in Example 2 and Comparative Examples 2 and 8 were applied on the plaster surface, respectively. Ten composite resin discs were prepared for each mold release material. An adhesive area was defined by sticking a tape having a hole of 4 mm in diameter on the surface of this disc that was in contact with the release material. A paste prepared by kneading a dental adhesive "Panavia EX" according to the instruction manual was applied to the adhesive surface of the above sample, and a 5 mm diameter round bar made of SUS-304 was vertically placed and adhered thereon. The adhesive strength was measured by pulling at a crosshead speed of 2 mm / min using the Instron universal test period, and the values shown in Table 5 were obtained as an average value of 10 samples. From this result, it is clear that the mold release material of the present invention does not adversely affect the adhesion of the resin in contact with it.

[Table 5]

Claims (1)

[Claims] 1. A mold release material composed of water and a film-forming clay mineral insoluble in water, wherein the composition has thixotropic properties, and the thixotropic properties are released by shaking a container containing the thixotropic properties. The mold releasing material is characterized in that it exhibits fluidity, and when the composition is allowed to stand, thixotropy is again exhibited within 10 seconds and the fluidity disappears.