JPS6150560A - Resin denture bed - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an injection molding method in which a thermoplastic heat-resistant resin is injection molded using a plaster mold surrounded by a flask and surrounding a denture base-shaped cavity. molded using a method or compression molding method, etc.
The present invention relates to a resin denture base obtained by crushing a plaster mold after cooling and hardening the resin.

Shibago's technology Conventional resin denture bases have been made using acrylic resin for many years, and have been based on a pressure molding method that involves heat polymerization of polymers and monomers. This has the advantage that it is easy to perform one-time repairs using the same acrylic polymer powder and 7-acrylic monomer liquid as repair materials.

However, the denture base obtained by heating polymerization of such acrylic resin is brittle, the thin part often breaks due to occlusal force, the strength is weak, and the heating polymerization reaction is often insufficient. If the residual monomer is eluted and causes allergic symptoms, it also has hygienic drawbacks.

Therefore, in order to eliminate these drawbacks, a method of injection molding polysulfone resin using a plaster mold has been proposed, and it is beginning to be put into practical use.

This polysulfone resin has -8 engineering plastics, high mechanical strength, and excellent impact resistance, but it has poor adhesion to the commonly used acrylic resin artificial teeth, and special maintenance equipment is required. However, even if an adhesive is used, the adhesion is still insufficient, and there are practical problems such as the artificial tooth being easily dislodged when biting into relatively hard food, for example.

In addition, polysulfone resin causes stress cracking when it comes into contact with acrylic monomer solution, so the instant polymerization resin used for repairing conventional acrylic resin denture bases cannot be used, and the repair is a solid layer, making it difficult to use for a long time. However, there is a strong need for a thermoplastic resin denture base that can sufficiently withstand acrylic monomers.

Problems to be Solved by the Invention It is an object of the present invention to provide a thermoplastic resin denture base that can eliminate the conventional drawbacks. That is, in a resin denture base obtained by molding a thermoplastic heat-resistant resin with a plaster mold surrounding a denture base-shaped cavity and crushing the plaster, acrylic resin resin 01 is used as an artificial tooth. It provides strong adhesion between the denture base and the denture base, and does not cause cracks even when it comes into contact with the acrylic monomer liquid used during repairs, which is a characteristic required for denture bases.
That is, the object of the present invention is to provide a tooth base made of resin that has all the characteristics of transparency, gingiva-like coloration, strength, and rigidity.

A further feature of the present invention is that a thermoplastic heat-resistant resin is molded by injection molding, extrusion molding, transfer molding, compression molding, etc. using a plaster mold surrounding a denture base-shaped cavity. ,
In a resin denture base obtained by crushing a plaster mold, the thermoplastic heat-resistant resin is a mixture of functional derivatives of terephthalic acid and isophthalic acid (the molar ratio of terephthalic acid groups to isophthalic acid groups). (9:1 to 1:9) and 2,2-bis(4-hydroxyphenyl)propane is a blend of this and polycarbonate.

The aromatic polyester copolymer used in the present invention is a mixture of terephthalic acid and isophthalic acid and their functional derivatives (one copolymer is used, and the molar ratio of terephthalic acid groups to isophthalic acid groups is 9:1 to 1). :9) and 2,2-bis(4'-hydroxyphenyl)propane (hereinafter abbreviated as bisphenol).

As a method for producing such an aromatic polyester copolymer, a so-called interfacial polymerization (interfacial polymerization) is carried out, in which aromatic dicarboxylic acid chloride dissolved in an organic solvent that is incompatible with water and bisphenols dissolved in an alkaline aqueous solution are reacted. W,
M.

Eareckson, J., Poly, 8ci.
XL 399.1959, special public show 4Q-19591,
Solution polymerization (A) in which aromatic dicarboxylic acid chloride and bisphenols are reacted in a gastrointestinal solvent.

Con1x, Ind, Eng, Chcm, 51
147, l 959, Special Publication No. 37-5599),
Melt polymerization in which aromatic dicarboxylic acids and bisphenols are heated in the presence of acetic anhydride (Japanese Patent Publication No. 38-15247) Melt polymerization in which aromatic dicarboxylic acids and bisphenols are heated in the presence of diaryl carbonate (Japanese Patent Publication No. 88-2
6299) and other methods are known.

The aromatic polyester copolymer used in the present invention includes:
Polycarbonate, polyester carbonate, or polyethylene terephthalate can be blended in an appropriate amount depending on the purpose. These resins have good compatibility with the aromatic polyester copolymer, and have the characteristics required for aromatic polyester copolymers for denture bases, such as transparency, color tone, strength, and rigidity, and acrylic resin artificial teeth. The processing temperature can be lowered without degrading the adhesion to the 7-acrylic monomer, the resistance to the 7-cryl monomer, etc. Further, the aromatic polyester copolymer is preferred because it has the advantage that the yellowish tint is reduced and a variety of colors required for denture bases are possible.

In particular, when the mixture is composed of 30 to 95% by weight of the aromatic polyester copolymer and 70 to 5% by weight of polycarbonate, the transparency, color tone, strength, rigidity, and adhesion to acrylic resin artificial teeth. It exhibits better resistance to crylic monomers and denture base moldability by injection molding, compression molding, etc. than the aromatic polyester copolymer alone, and has high surface hardness and excellent abrasion resistance by toothbrushes. It is preferable because it has better properties than #1 tooth base, such as good finishing workability by machining after molding the denture base. The polycarbonate preferably blended in the present invention is 4.4-di Oxydiallylalkane polycarbonates, such as bis(4-hydroxyphenylcomethane, bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxy-3,5 −
4 such as dichlorophenyl)methane, 2,2-bis(4-hydroxy-8,5-dimethylphenylbis(4-hydroxyphenyl)phenylmethane)
．． It is obtained from 4-dioxydiphenylalkane and phosgene or diphenyl carbonate. Such polycarbonates can be manufactured by various methods such as known melt polymerization and interfacial polymerization.

In addition, aromatic polyvarnish used in the present invention 1
For the chill copolymer or its mixture, antioxidants and heat stabilizers,
One or more conventional additives may be added, such as ultraviolet absorbers, lubricants, mold release agents, and colorants such as dyes and pigments.

Function The present invention uses the aromatic polyester copolymer as a thermoplastic resin, melts it by injection molding or compression molding, and molds the thermoplastic resin into a plaster mold containing an acrylic resin artificial tooth. After shaping, the plaster mold was crushed and the resulting denture base was made of acrylic resin artificial teeth. Even without adhesive, it exhibits high adhesion to acrylic resin artificial teeth, and does not generate any cracks even when brought into contact with acrylic monomer liquid used for masonry and repair.

Hereinafter, the present invention will be specifically explained with reference to Examples, but these are illustrative of preferred embodiments, and the present invention is not limited to the scope of the actual examples.

Practical example 1 According to the single artificial tooth fracture test piece method described in Japanese Industrial Standard JIS T-6511, as shown in Figure 1, an acrylic resin artificial tooth (trade name: GC Acrylic Resin Front Teeth)
1 is planted on a paraffin wax master so that the line connecting the incisal end l and the frontal part 1 is at a 45° angle with the paraffin wax master, and after embedding it in plaster in a flask, it is poured with wax.
Form a plaster mold.

Attach this plaster mold to an injection molding machine, set the cylinder temperature to 860°C, the injection pressure to 1500, and the injection speed to 25.
0 x 47 seconds (G type machine: Sumitomo Neschool P40/2
Under the conditions of 5), a gingiva-colored aromatic polyester copolymer (a methylene chloride solution of a mixed acid chloride with a ratio of terephthalic acid dichloride/isophthalic acid dichloride of 1:1 and an alkaline aqueous solution of bisphenol) Legally obtained, phenol/tetrachloroethane (
Logarithmic viscosity in 6:4 base ratio) or 0.62)') e
E. Inject 1 resin into the flask.

After cooling, divide the flask and take out the molded product for the artificial tooth fracture test.

As shown in Fig. 1, the resin bed part 2 is fixed with a holder 3, and the other artificial gear end part 1 is fixed with a predetermined metal fitting 4 at a load speed of 12K.
One that performs a fracture test at pf/min.

The fracture strength was 25 Kpf, which was a sufficiently high value to cause no practical problems.

Comparative Example 1 Polysulfone (Ode 1 Pl?00 manufactured by UCO) was used instead of the aromatic polyester copolymer used in Example 1.
The molding was performed in the same manner as in Practical Example 1 except that the artificial tooth fracture test was performed.

The fracture strength is only 7 Kf f L/T, which is a low value that would pose a practical problem.

Example 2 Artificial teeth made of acrylic resin (trade name: GC 7 Krylysocresin anterior teeth and molars) were implanted. A flask in which a wax model of the denture base was embedded was heated, the wax was softened, poured, and plastered. formed.

Attach the plaster mold to the injection molding machine and increase the cylinder injection speed to 20
Under the conditions of 0 m/sec (molding machine: Sumitomo I, School P40/25), a molten resin of an aromatic polyester copolymer similar to that used in Example 1, which was colored like gums, was injected into the flask. 1 injection.

After cooling, the flask was divided and the denture base was taken out. Even if the artificial tooth is pushed hard, it will not come off easily, and the artificial tooth will be firmly planted and a denture base will be obtained.

The denture base further contains an acrylic monomer used for repairing conventional acrylic resin denture bases!
Immediately polymerized resin for repairs (trade name: GC Repe 7gin) was WMed according to the conventional method, and overlay was built up on the aromatic polyester denture base using the moth spot method, but no abnormalities such as cracks were observed. First, it has been confirmed that it is possible to use this pre-polymerized resin for denture repair.

Comparative Example 2 In place of the r-aromatic polyester copolymer used in Example 2, polysulfone (UCCfRUdel P1700
) was used in the same manner as in Example 2 to obtain a denture base, but the artificial tooth was removed from the denture base with just one push.

After applying the instant polymerization resin for denture repair used in Example 2 to a polysulfone denture base in a similar amount, cracks were observed in the denture base.

Example 3 A flask in which acrylic resin artificial teeth (trade name: GC 7 Krylin resin anterior teeth, paralysis molars) and a gamma denture base wax model was embedded was heated to soften the wax.
After one flow waxing, the aromatic polyester and polycarbonate (Mitsubishi Gas Chemical!!!8200) used in Example 1 were heated.
Blend 0) in a ratio of 7 to 3 parts, and place the mixture into a gingiva-like color and a U-shaped molded product (U-shaped with a size that is convex to the alveolar ridge) into a plaster mold in the lower flask. Place the molded product on the top and blow hot air at 320°C to soften the molded product. Once it is sufficiently softened, put the upper and lower flasks together and perform compression molding, and then let it cool naturally. After cooling, the upper and lower flasks were separated and the denture base was taken out.

You can obtain a denture base in which the artificial tooth is firmly planted so that it does not easily come off even if the artificial tooth is pushed hard.

Also, as in Example 2, no abnormalities such as cracks were observed when the instant polymerized resin for denture repair was contacted.

Comparative Example 3 A denture base was prepared in the same manner as in Practical Example 8, except that polysulfone was used instead of the mixture of r-coaromatic polyester copolymer and polycarbonate used in Example 8, and the temperature of the hot air was 340°C. Get 1 piece.

The artificial tooth was removed from the denture base with a light push, and cracks were observed on the denture base when the instant polymerized resin for denture repair used in Example 3 was filled with similar masonry. child.

Effects of the Invention As described above, the present invention provides a resin denture base obtained by molding a thermoplastic heat-resistant resin using a stone mold surrounding a denture base-shaped nitrid cavity and crushing the plaster mold. By using an aromatic polyester copolymer or a mixture thereof as the plastic resin, it has good adhesion to acrylic resin artificial teeth, and the use of instant polymerization resin used for repairing conventional acrylic resin denture bases. This has the effect of making it possible.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the actual mode of the artificial meat fracture test. 1......Artificial tooth 1...Incisal end 1' of artificial tooth...Neck part 2 of artificial tooth...
...Resin floor part 3...Holder 4...Artificial tooth tension fitting Fig. 1

Claims (1)

[Claims] (1) Resin denture base obtained by molding thermoplastic heat-resistant resin by injection molding, extrusion molding, transfer molding, compression molding, etc. using a plaster mold surrounding a denture base-shaped cavity, and crushing the plaster mold. , the thermoplastic heat-resistant resin is a mixture of terephthalic acid and isophthalic acid or functional derivatives thereof (however, the molar ratio of terephthalic acid groups and isophthalic acid groups is 9:1 to 1:9) and 2,2-bis(4'). A resin denture base made of an aromatic polyester copolymer obtained from (hydroxyphenyl)propane, or a mixture of this and polycarbonate.