JP2904598B2 - 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.

[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 increases the material cost.

[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 clasb 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.

On the other hand, there is a method of using a pattern resin instead of the pattern wax. Resin for pattern is P
MMA-based instant-curing resin, which has higher elasticity than pattern wax, but hardens slowly and lacks sufficient elasticity, so it is the same as pattern wax when removed from the undercut of the working model within the working time With permanent deformation.

If a photopolymerizable compound is used instead of chemical polymerization, a pattern resin that cures quickly may be obtained. JP-A-1-110609 discloses a resin composition for a photopolymerization pattern using a photopolymerizable compound containing at least one ethylenic double bond which is solid at ordinary temperature. Although the operability, strength and castability of the resin are described in the same gazette, the operability and castability are not sufficient, especially when a gypsum-based investment material is used as the investment material for casting, The skin is terrible and practically unusable. Conventionally, such a technique has not been achieved despite many requests.

As described above, the technical problem of the lost wax method has been described by taking the dental field as an example, but the lost wax method is widely used not only in the dental field but also in other general industrial fields. A similar problem exists in the general industrial field.

[0017]

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

Another object of the present invention is to manufacture a partial denture, particularly in the field of dentistry, when manufacturing a cast clasp, which is a metal component for imparting grip, maintenance and support of a denture, by a lost wax method. Another object of the present invention is to provide a photo-curable resin composition for producing a prototype of a clasp, ie, a pattern of a clasp, which exhibits a theoretical shape with respect to maintenance power, durability and the like.

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) 40 to 100% by weight of a polycarbonate containing at least two (meth) acrylate groups in a molecule having a molecular weight of 200 to 10,000 and (A) (B) 30 to 60 parts by weight of an acrylate monomer composed of 0 to 60% by weight of a meth) acrylate compound; And (C) a photocurable resin composition containing 0.04 to 4 parts by weight of a photoradical polymerization initiator.

The acrylate monomer (A) constituting the photocurable resin composition of the present invention is, as described above, a polycarbonate alone containing at least two (meth) acrylate groups in a molecule having a molecular weight of 200 to 10,000. Or the polycarbonate and the (meth) acrylate compound. When it is composed of a polycarbonate and a (meth) acrylate-based compound, the content of the (meth) acrylate-based compound is 60% by weight or less, preferably 50% by weight or less based on the total weight of both.

The polycarbonate constituting the photocurable resin composition of the present invention has a (meth) acrylate group, that is, an acrylate group or a (meth) acrylate group in the molecule, for example, at the molecular terminal.

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

[0024]

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

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

Specific examples of such polycarbonates 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;
10,000 terminal hydroxyl group polycarbonate oligomers and O
A (meth) acrylic acid ester having one or two H groups and a diisocyanate compound are reacted at once or in two steps to obtain two (meth) acryl groups via urethane groups at both ends of a polycarbonate. And a compound obtained by reacting a polymer having the same or a polycarbonate oligomer having a terminal hydroxyl group with a (meth) acrylate compound having an isocyanate group.

As the (meth) acrylate compound constituting the acrylate monomer of the composition of the present invention together with the above polycarbonate, any of monofunctional, difunctional and higher polyfunctional compounds with respect to the (meth) acrylate group can be used. Can be used. Examples of such (meth) acrylate compounds include monofunctional (meth) acrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, glyceryl methacrylate, and ethylene glycol monomethacrylate; ethylene glycol di ( (Meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate,
Polyethylene glycol di (meth) acrylate, dimethacrylic acid ester of bisphenol A, diglycidyl methacrylate of bisphenol A, 2,2-bis (4
-Methacryloxyethoxyphenyl) propane, 2,2
-Bis (4-methacryloxy (poly) ethoxyphenyl) propane, a condensate of one molecule of 2,2,4-trimethylhexamethylene diisocyanate and two molecules of hydroxyethyl (meth) acrylate, one molecule of hexamethylene diisocyanate and hydroxyethyl ( (Meth) acrylate 2
Molecular condensates, bifunctional (meth) acrylates such as diglycidyl methacrylate phthalate, and polyfunctional (meth) acrylates such as trimethylolpropane trimethacrylate and pentaerythritol trimethacrylate are exemplified. It is not limited.

The (meth) acrylate monomer (A) is used in an amount of 30 to 60 parts by weight, preferably 35 to 55 parts by weight.

[0030] Examples of the organic polymer of the organic polymer fine powder (B), Po polymethyl methacrylate For example, polyethyl methacrylate, polybutyl methacrylate, may be mentioned as preferred starch, paraformaldehyde and the like.

These organic polymers are preferably 1,0
It is desirable to contain only ash of 00 ppm or less, more preferably 500 ppm or less.

Further, these organic polymers have a number average molecular weight of 10,000 to 2,000,000, preferably 20,000 to 1,000,000.

The fine powder of the organic polymer has an average particle diameter of 1 to 1.
It has 50μ, preferably 2-40μ.

The organic polymer fine powder is used in a proportion of 40 to 70 parts by weight, preferably in a proportion of 45 to 65 parts by weight.

As the photo-radical polymerization initiator (C), known ones can be used without distinction. Preferably, camphorquinone, benzyl, benzoylmethyl ether, benzoin isopropyl ether, thioxanthone derivatives,
Benzophenone, acetophenone and the like can be mentioned as preferred.

The photo-radical polymerization initiator is 0.04
To 4 parts by weight, preferably 0.1 to 3 parts by weight.

The photocurable resin composition of the present invention is produced by sufficiently stirring and mixing the above three components (A), (B) and (C) sequentially or simultaneously in an arbitrary order. be able to.

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

[0039]

【Example】

Example 1 molecular terminal acrylate groups _(CH 2 = CHCOO-) polycarbonate having (Negami Kogyo Co., Art Resin UN9200S) 0.7 g, phthalic acid diglycidyl methacrylate (Nagase Chemicals Ltd., Denacol DA72
1) 0.3 g, polymethyl methacrylate having an average particle diameter of 30 μm and a molecular weight of 500,000 (Negami Industry Co., Ltd., Hyperl D)
250M) 0.6 g and hydroquinone 0.002 g were mixed with a spatula, heated at 76 ° C. for 30 minutes to form a viscous paste, and then paraffin wax (Nippon Seiro Co., Ltd., L
UVAX0321) 1.3 g, camphorquinone 0.1
6 g, 0.016 g of dimethyl-p-toluidine were added,
Mixing and defoaming under vacuum gave a paste-like resin composition.

[0040]

Example 2 1 g of a polycarbonate having an acrylate group at a molecular end (Negami Kogyo Co., Ltd., UN9200S), paraffin wax (Nippon Seiro Co., Ltd., LUVAX 0321) 1
g, corn starch having an average particle size of 15 μm and a molecular weight of about 1,000,000 0.3 g of corn starch, 0.001 g of hydroquinone, 0.017 g of camphorquinone, 0.017 g of dimethyl-p-toluidine were mixed with a spatula, and vacuum was applied. Defoaming was performed to obtain a paste-like resin composition.

Comparative Example 1 10 g of urethane acrylate (Negami Kogyo Co., Ltd., Art Resin SH100), 5 g of polymethyl methacrylate (Shinnakamura Chemical Co., Ltd., Hyper D250M), 0.05 g of camphorquinone, 0 g of dimethylaminoethyl methacrylate 0.05 g and 0.003 g of di-t-butylhydroxytoluene were mixed with a spatula and defoamed under vacuum to obtain a paste.

The pastes of Examples 1 and 2 and Comparative Example 1 were used in a
For a 5mm diameter cylinder with a 5mm undercut, 3
/ 4 laps, and after irradiating with a light irradiator (for dental use, Morita Co., Ltd., α-light) for 5 minutes, pull out from the undercut and remove the plaster-based investment material (Tokuyama Soda Co., Ltd., White Vest M) ) And buried in the usual way,
Castings were obtained with silver and palladium alloys. Casting surface condition,
The skin was as shown in Table 1.

[0044]

[Table 1]

[0045]

The photocurable resin 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 in producing a pattern of a casting clasp, and has excellent surface properties and gives a pattern of a casting clasp having little or no deformability.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI C08L 101/00 C08L 101/00 (56) References JP-A-5-140252 (JP, A) JP-A-63-270641 (JP) JP-A 1-6236 (JP, A) JP-A 4-208251 (JP, A) JP-A-60-108477 (JP, A) JP-A-60-51766 (JP, A) 63-15821 (JP, A) JP-A-63-264621 (JP, A) JP-A-63-165420 (JP, A) JP-A-62-129306 (JP, A) (58) Fields investigated (Int. 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. An acrylate system comprising (A) 40 to 100% 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 0 to 60% by weight of a (meth) acrylate compound. 30 to 60 parts by weight of a monomer, (B) 40 to 70 parts by weight of a fine powder of an organic polymer having an average particle diameter of 1 to 50 μm and a molecular weight of 10,000 to 2,000,000, and (C) a photoradical polymerization initiator 0.04 to 4 A photocurable resin composition containing parts by weight.