JP2904597B2 - Photocurable resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photocurable resin composition. More specifically, in manufacturing a partial denture, the casting clasp, which is a metal component that imparts gripping (resistance to lateral movement), maintenance (resistance to detachment), and support (resistance to occlusal pressure) of the denture, is lost. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable resin composition for forming a prototype of a casting clasp, that is, a pattern of a clasp, which exhibits a theoretical shape with respect to retention force, durability, and the like when manufactured by a wax method. Such a photocurable resin composition used in the lost wax method is useful in dental and general industrial fields.

[0002]

2. Description of the Related Art Clasps are used for more than 90% of main and indirect maintenance devices for partial dentures. However, especially in the case of a casting clasp, its manufacturing method is complicated, and its maintenance force, adaptation accuracy, and given form of the arm are not always satisfactory.

[0003] In a conventional method of manufacturing a casting clasp, first, a jaw impression in a patient's mouth is collected, and a working model is made of cemented plaster or the like. Next, in order to design a clasp serving as a maintenance device, surveying is performed on the maintenance tooth portion on the working model. Surveying is the work to find the largest remaining portion of the model and the remaining teeth on the model and the ridge, and also to check the parallel relationship between them. This is an extremely important operation in the manufacture of dentures, such as measuring the amount of undercut and determining the position of the clasp.

[0004] Important factors that influence the holding force of the clasp include the length, thickness, cross-sectional configuration, Young's modulus of the alloy used, the set amount of undercut, the curvature of the tooth surface of the holding teeth, and the like. No.

When a casting clasp is manufactured using a paraffin-based wax pattern, the retaining force of the clasp is:
It can be controlled by selecting the amount of undercut to be used, the thickness of the pattern, and the selection of different cross-sectional forms.
At the time of surveying and at the time of designing a denture, it is required to design a clasp corresponding to the state of the periodontal tissue of the maintenance tooth.

[0006] When the design and block-out of the working model is completed, the maintenance teeth portion that has been blocked out according to the design is again taken (double impression) in order to produce a wax pattern of the clasp, and the working model is used as a model investment material. Replace with Next, taking into account the precise control of the clasp retention force, bend the clasp pattern of paraffin wax with your fingers and attach it to the investment material for the model using an adhesive to form the rest and legs. The sprue is planted. Next, without removing the paraffin wax clasp pattern from the model investment, the model investment is buried in the casting investment, and after the investment is hardened, the paraffin clasp pattern is heated by furnace. After incineration, a melted metal is poured into a mold having a clasp pattern formed thereafter and cooled, and index polishing is performed to complete the clasp (hereinafter, this method is referred to as "mold burial method").

[0007]

The above-mentioned method for producing a casting clasp has the following problems since the material for forming the clasp pattern is a paraffin wax.

[0008] Since paraffin wax cannot be elastically deformed at all and plastically deforms, it cannot be removed from the undercut portion of the maintenance tooth on the working model through the maximum ridge.

[0009] If removed forcibly, permanent deformation occurs, and accurate fitting cannot be obtained. For this reason, it is not possible to create an accurate clasp with controlled retention. Therefore, the clasp pattern of the paraffin wax always makes a double impression of the working model, replaces it with the investment material for the model, forms the clasp pattern on the investment material for the model, and buries the investment material for the model with the investment material for casting. The so-called burial method must be performed for each type.
For this reason, the clasp manufacturing process is complicated, requires a long manufacturing time, and the material cost is increased.

[0010] Since the clasp pattern of paraffin wax does not adhere to the investment material for the model or the plaster, an exclusive adhesive must be used without fail. Therefore, the thickness of the adhesive becomes a clasp having an error of about 50 μm, and a clasp having good compatibility cannot be obtained.

The clasp pattern of paraffin wax is pressed with fingers using an adhesive and adheres to the investment material for the model. At this time, the strength of the investment material is low, so that the particles of the investment material are peeled off and the shape of the teeth for maintaining the teeth is reduced. The surface properties deteriorate.
The separated particles of the investment material adhere to the clasp pattern of the paraffin wax, so that a cast clasp having good surface properties cannot be produced.

The paraffin wax clasp pattern is a polymer having high crystallinity and a relatively low molecular weight.
Since the glass transition temperature Tg and melting point Tm are very close to each other, but the material does not have a glass transition point like metal, if the temperature rise rate during heating and incineration of the wax is too large, the melted wax will boil and gas Since the lost wax expands, the investment material is suddenly pressurized, and the investment material is cracked or the inner surface of the investment material is roughened.

The present invention aims to develop a clasp pattern made of a new material in place of paraffin wax in order to solve these problems.

[0014]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a novel photocurable resin composition which is useful not only in dental applications but also in general industrial fields.

Another object of the present invention is to solve the above-mentioned drawbacks of the conventional method and to improve the operability, resin strength and castability.
It is to provide a photocurable resin composition suitable as a pattern resin composition.

Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and advantages of the present invention are as follows: (A) (A) in a molecule having a molecular weight of 200 to 10,000
Polycarbonate 1 containing at least two acrylate groups
5 to 60 parts by weight, (B) 20 to 70 parts by weight of polyolefin fine powder having an average particle diameter of 1 to 50 μm, (C) oligomer and / or polymer 2 having solubility in (meth) acrylic acid ester monomer This is achieved by a photocurable resin composition in the form of a paste having good operability containing 40 parts by weight and (D) 0.05 to 4 parts by weight of a photoradical polymerization initiator.

The polycarbonate constituting the photocurable resin composition of the present invention may have (meth)
It has an acrylate group, that is, an acrylate group or a methacrylate group.

The skeleton of the polycarbonate may be either aliphatic or aromatic. As the skeleton of such a carbonate, for example, an alkylene carbonate group having 2 to 20 carbon atoms or the following formula 1

[0020]

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And those having a group represented by the following formula as a main repeating unit.

The molecular weight of such a polycarbonate is 200
１10,000, preferably 300３００5,000.

Specific examples of such a polycarbonate include, for example, a polymer in which the terminal hydroxyl groups of a polycarbonate oligomer having a terminal hydroxyl group of a molecular weight of 200 to 10,000 are esterified with (meth) acrylic acid or glycidyl (meth) acrylate; Urethane groups at both ends of a polycarbonate obtained by reacting, at once or in two steps, a polycarbonate oligomer having a terminal hydroxyl group of up to 10,000, a (meth) acrylate ester having one or two OH groups and a diisocyanate compound. And a compound obtained by reacting a polymer having two (meth) acrylic groups or a polycarbonate oligomer having a terminal hydroxyl group with a (meth) acrylate compound having an isocyanate group through the above.

The polycarbonate is used in an amount of 15 to 60 parts by weight, preferably 20 to 55 parts by weight.

As the polyolefin fine powder (B),
For example, fine powder such as polyethylene, polypropylene, and polybutylene is preferably used.

These finely divided polyolefins have a number average molecular weight of preferably 10,000 to 2,000,000, more preferably 20,000 to 1,000,000.

The polyolefin fine powder has an average particle size of 1 to 50 μm, preferably 2 to 30 μm.

The polyolefin fine powder is used in a proportion of 20 to 70 parts by weight, preferably in a proportion of 25 to 60 parts by weight.

A (meth) acrylate monomer,
Examples of the oligomer and / or polymer (C) having solubility in methyl methacrylate, ethyl methacrylate, and the like include, for example, ketone resins, xylene resins,
Examples thereof include oligomers such as alkyd resins, petroleum resins, rosins, modified rosins, and terpene phenol resins, and polymers such as polymethyl (meth) acrylate, polyethyl (meth) acrylate, polybutyl (meth) acrylate, and polystyrene.

Such oligomers and / or polymers are used in 2 to 40 parts by weight, preferably 4 to 30 parts by weight.

As the photoradical polymerization initiator (D), for example, ultraviolet light initiators such as benzoin alkyl ether, benzophenone and acetophenone, and visible light initiators such as camphorquinone, bensyl, Michler's ketone and thioxanthone derivatives are preferably used. . Of these, the latter, such as a visible light initiator, is preferably used because it gives a composition having excellent curability.

The photo-radical polymerization initiator is 0.05
To 4 parts by weight, preferably 0.1 to 3 parts by weight.

The composition of the present invention comprises the above components (A) to
In addition to (D), if necessary, various curing accelerators such as amines such as dimethyl-p-toluidine, diethanol-p-toluidine, and dimethylaminobenzoic acid, and sulfur compounds such as dimethylthiourea and thiobenzoic acid may be used. The accelerator can be contained at 5% by weight or less, and a polyfunctional (meth) acrylate monomer can be contained within 35% by weight for the purpose of improving the hardness of the cured product.

The composition of the present invention usually takes the form of a paste. The components (A) and (B) make the greatest contribution to the composition of the present invention exhibiting a paste form.

Component (C) is the operability of the paste composition,
It is particularly effective for suppressing the deformation of the paste.
If the amount is less than 40 parts by weight, the effect is not obtained.
If the component (D) is less than 0.05, the effect will be insufficient.
If the amount is more than 4 parts by weight, coloring of the paste, an increase in cost, a decrease in the strength of the cured product, and the like will occur.

The photocurable composition of the present invention comprises the above (A)
It can be produced by sufficiently stirring and mixing the components (B), (C) and (D) sequentially or simultaneously in an arbitrary order.

The composition of the present invention is suitably used for producing a pattern of a dental casting clasp.

That is, the composition of the present invention is excellent in operability when producing a pattern of a casting clasp, and is also excellent in resin strength and castability. As mentioned above, the case where the composition of the present invention is mainly used for dental casting has been mentioned. However, as described above, the composition of the present invention can also be used in general industrial fields.

Hereinafter, the present invention will be described in detail with reference to examples. The present invention is not limited by these examples.

[0040]

[0041]

[0042]

REFERENCE EXAMPLE 1 A hexamethylene carbonate oligomer (manufactured by Nippon Bayer K.K., desmophene 2) was added to 5 ml of tetrahydrofuran.
020E) of 10 g and 1.85 g of methacryloyloxyethyl isocyanate (manufactured by Nippon Denko Co., Ltd.) in 0.012 g of di-n-butyltin dilaurate and 0.1 in hydroquinone.
001 g was dissolved and stirred and mixed at room temperature for 4 days. The tetrahydrofuran was removed from this under reduced pressure at room temperature to obtain a white semi-solid precipitate. When 1R of this product was measured,-
It was found that the absorption at cm-1 due to NCO disappeared, and urethanization occurred.

[0044]

EXAMPLE 1 Reaction and product 1g of Example 1, a polycarbonate having both molecular ends acrylate group (Negami Chemical Industrial Co., Ltd., U
N9000SM) 1 g, trimethylolpropane trimethacrylate 0.5 g, polyethyl methacrylate (Hyperl D-250M, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.25
g, hydroquinone 0.002g mixed with a spatula for 30 minutes heated at 76 ° C. in an oven, cooled, polyether
Tylene powder (Flocene UF80, manufactured by Sumitomo Seika Co., Ltd.)
2.75 g, photoinitiator (MERCK, Darocur)
e1664) 0.055 g and dimethyl-p-toluidine 0.03 g were mixed and defoamed under vacuum to obtain a paste.

Example 2 8 g of UN9000S, 2 g of trimethylolpropane trimethacrylate, 1 g of polyethyl methacrylate (Hyperl D-250EL, manufactured by Shin-Nakamura Chemical Co., Ltd.), polycarbonate oligomer (Desmophen 2020E, manufactured by Sumitomo Bayer Urethane Co., Ltd.), 0.008 g of hydroquinone was mixed with a spatula, heated in an oven at 76 ° C. for 30 minutes, cooled, and then cooled to an average particle size of 20 to 30 μm.
Polyethylene powder (manufactured by Sumitomo Seika Co., Ltd., Flowsen UF)
80) 16 g, camphorquinone 0.055 g, and dimethyl-p-toluidine 0.03 g were mixed and defoamed under vacuum to obtain a paste.

Comparative Example 1 10 g of urethane-based acrylate (art resin U108A, manufactured by Shin-Nakamura Chemical Co., Ltd.) and polymethyl methacrylate powder (Hyperl D250M, manufactured by Shin-Nakamura Chemical Co., Ltd.)
It was obtained mixture butylhydroxytoluene 0.003g with a spatula, and vacuum defoaming the paste-like product - 5 g, camphorquinone 0.05 g, dimethylaminoethyl methacrylate 0.05 g, di t.

The plagues of Examples 1 and 2 and Comparative Example 1 were prepared with a diameter of 5
the rod of the true Ju c of mm in a mold dug undercuts 0.5 mm, wound up 3/4 laps annular light irradiator (dental, Morita Co. α- light) for 5 minutes light after irradiation From the undercut. Using a gypsum-based investment material (White Vest M, manufactured by Tokuyama Soda Co., Ltd.), a casting was prepared from a dental gold-silver palladium alloy according to a usual method, and the surface state and deformation of the casting were examined. The results are as shown in Table 1.

[0048]

[Table 1]

Continuation of the front page (51) Int.Cl. ⁶ identification code FI C08L 69/00 C08L 69/00 (58) Field surveyed (Int.Cl. ⁶ , DB name) C08F 299/00-299/08 C08F 290 / 00-290/14 A61K 6/00-6/10 C08F 2/00-2/60 C08L 1/00-101/14

Claims (1)

(57) [Claims] 1. (A) 15 to 60 parts by weight of a polycarbonate having at least two (meth) acrylate groups in a molecule having a molecular weight of 200 to 10,000, and (B) a fine powder of polyolefin 20 having an average particle size of 1 to 50 μm. To 70 parts by weight, (C) 2 to 40 parts by weight of an oligomer and / or polymer having solubility in a (meth) acrylic ester monomer and (D) 0.05 to 4 parts by weight of a photoradical polymerization initiator. Paste photocurable resin composition with good operability.