JPH0696486B2 - Method for forming dental functional composite structure using polyurethane elastomer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a denture base, a maintenance structure, a mouthpiece, an orthodontic device,
The present invention relates to a method for forming a functional composite structure using a polyurethane elastomer suitable for the dental field such as gum material.

(Prior Art) An attempt to use a polyurethane elastomer as a dental material has been proposed by Miyake et al. For more than 20 years, but the original polyurethane elastomer had many problems in physicochemical properties and biomaterials. There were many unconfirmed points in terms of safety. After that, the above problems were gradually improved with the development of polyurethane technology, but the dental material still has the following improvements.

(Problems to be solved by the invention) That is, (i) conventional polyurethane elastomers tend to deteriorate in strength due to weakly acidic alkaline in the oral cavity, and (ii) hydrophilicity of polyurethane is good in oral cavity. It became a factor of familiarity and strong adhesive strength, but on the other hand, it was found that this hydrophilicity causes contamination. (Ii
i) When exposed to sunlight for a long time, it turns yellow and becomes a color that is incompatible with the color of biological tissue, reducing the commercial value.

The object of the present invention is therefore to solve the above three problems and to be a polyol which is a soft segment of polyurethane,
A polyurethane elastomer member having rigidity and a flexible and highly elastic elastomer, or polyurethane, while allowing various molecular designs by appropriately distributing soft and rigid properties by arbitrarily combining with diisocyanate which is a hard segment It is intended to provide a method capable of realizing a functional composite structure by stacking an elastomer and another material in a state of having a high chemical bond with each other to form a stack.

(Means for Solving Problems) The inventors of the present invention have been earnestly engaged in research and development of dental polyurethane elastomers for many years from a polymer technical viewpoint and a clinical viewpoint. As a result, a dental polyurethane elastomer comprising a reaction product of at least one selected from a polycarbonate and a polyol as a polyol or a polybutadiene diene and a polysiloxane diol and a non-aromatic diisocyanate as a diisocyanate solves the above problems. It was provided separately by Japanese Patent Application No. 59-267102, knowing that it is effective for.
As a polyol for making the degree of hydrophilicity in this elastomer slightly hydrophobic, it can be assumed that a polyether or a polythioether having an ether bond is not easily hydrolyzed, but the ether bond itself is not hydrolyzed. Nevertheless, it has been found that the water absorption of the elastomer becomes large and the purpose cannot be achieved. As a result of such trial and error, polycarbonates, polybutanediene polyols, and polysiloxanes having a low content of S-bonds are used as polyols that should be able to make part of the hydrophilicity hydrophobic without sacrificing the tackiness. We have found that at least one selected from diols is optimal. Although the former is different from the latter in that it is more excellent in mechanical properties, both can impart good hydrolysis resistance to the elastomer. On the other hand, with respect to the diisocyanate that is the hard segment H, a non-aromatic diisocyanate such as an alicyclic diisocyanate having an alicyclic structure and isoporone diisocyanate (IPDI) is necessary for realizing tough yellowing. As a cross-linking agent for urethane-bonding the above-mentioned polyol and this non-aromatic diisocyanate, methylene bis ortho chloroaniline (MOCA), 1.4 butanediol, trimethylolpropane, etc. are used. Amount of polyol,
The hardness of the elastomer can be adjusted from JIS A15 to JIS D100 by selecting the amount of diisocyanate and the amount of cross-linking agent.
In (Example) described later, the softer the
The older it is, the harder it is. Usually NCO / NH ₂ or O of polyol and non-aromatic diisocyanate
Since the crosslinking reaction is completed by setting H to about 1.00 to 1.08, if the composite structure described below is not taken, crosslinking can be achieved by simply pouring the prepolymer into the template under the above NCO / NH ₂ or OH distribution. Curing is complete and no injection molding is required. However, when using a multilayer structure, NC
O / NH ₂ or OH (hereinafter simply referred to as NCO ratio) 1.05 to 1.
By increasing the amount to about 25, a large amount of free isocyanate is present in the cross-linking reaction state, which significantly inhibits chain extension and delays curing, which requires a method of preventing curing for a long time in a viscous state. Become. In this context, the functional composite structure refers to the rigidity required for the denture base to be strongly affected by the occlusal pressure. Contrary to this, on the other hand, the functional composite structure is required to be in contact with the mucosal tissue because the influence of the occlusal pressure is small. Polyurethane elastomers of the present invention having different physical properties so as to be adaptable to different properties such as flexibility (provided that they are distinguished by the temper and soft temper), a prepolymer separate from the present elastomer (for example, It refers to a structure that achieves multiple functions while being a composite denture base composed of two or more members composed of a primer coated on a polymer material different from metal or polyurethane). Casting such a large number of members in separate cycles is disadvantageous not only in terms of process, but also requires an embedded molding technique that uses injection molding as a pace, as well as chemical bonding between members. The sex becomes insufficient. Therefore, in the present invention, the formation of such a multilayer structure is as described above.
Considering the NCO ratio, a large number of free NCO groups remain to maintain the plastic range without reaching the final curing of the elastomer (this state is referred to as reaction dormant state), and the NCO ratio is adjusted to reach this state. Another polyurethane prepolymer of the present invention having a OH group or NH ₂ group at the terminal or side chain in the molecule or a known polyurethane is used to form a primary structure by casting using the polyurethane material of the present invention. The secondary structure is formed by contacting the primary structure with an elastomer or another elastomer. In order to adjust the NCO ratio as described above, conventionally known chain extenders such as polyols, polyamines, and alkanolamines are used alone or in combination. The structure includes a layer, a film, and any molded member having a desired shape. In the above method, the primary structure is preliminarily polymerized to some extent by heating before the secondary structure is poured (prepolymerization) to shorten the final polymerization time of the secondary structure. It is desirable in the sense that the primary structure does not undergo plastic change on the above or by pouring of the secondary structure. When the NCO ratio in the elastomer of the present invention is set to about 1.05 to 1.25, 1
By heating at 00 to 115 ° C for 24 to 36 hours, it reacts with moisture in the atmosphere to reach a final reaction termination state. Therefore, the prepolymerization can be carried out by setting the heating temperature and time to the above values or less. As an example, the prepolymerization is 80-
Heating is performed at 100 ° C. for 30 to 40 minutes, and as complete polymerization at 80 to 100 ° C. for 15 to 24 hours. As an example of the secondary structure, a primer coated on a polymer material different from metal or polyurethane can be used. For example, when combining a metal member and a primary structure, a secondary structure is provided in the middle between the two, and a primer layer (in this primer, as described above, an OH group or an NH ₂ group is added to the end or its side chain). The metal member and the primary structure are integrally formed by the secondary structure therebetween. In the polyurethane elastomer of the present invention, a pigment, a hydrolysis inhibitor, a heat stabilizer, and a reaction accelerating catalyst can be added as a plain or batter if necessary. An example of how to obtain such a composite structure will be described with reference to FIG. 5 by taking a denture base as an example. In this example, the main part (11) of the denture base (1) excluding the front tooth part (10) is made of a rigid polyurethane elastomer (that is, diisocyanate-rich), and the front tooth part (10) is made of a flexible polyurethane elastomer (that is, polyol-rich). ) Shows the case of composite formation respectively, and the former elastomer prepolymer (20) containing a crosslinking agent is put in the container (2) and the NCO ratio is 1.15 to 1.2 as described above.
It is mixed with the chain extender (3) so as to be 5 and injected between the molds (A) and (A) ', followed by prepolymerization at 80 ° C for 1-2 hours to increase the viscosity, and then the mold (A). By releasing ′, the injection agent corresponding to the front tooth part (10) is peeled off, and then another mold (B) is butted against the mold (A), and the prepared flexible container (4) is adjusted. The polyurethane prepolymer (21) and the chain extender (5) were mixed so that the NCO ratio was 1.05 to 1.10, and the mixture was injected into the cavity corresponding to the front tooth portion between the castings (A) and (B), and thereafter. The prepolymers (20) and (21) are allowed to complete polymerization at 80 ° C for 12 hours, and then the molds (A) and (B) are released to form a main part (11) made of a rigid polyurethane elastomer. A denture in which the front tooth part (10) made of a flexible polyurethane elastomer is bound and integrated with chemical affinity at the interface between them. Floor (1)
Figure out. After that, the denture base (1) is polished to obtain a product.

(Function) In the present invention, by selecting a polyol having a small number of ester bonds such as a polycarbonate polyol or a polybugen polyol, it is possible to impart good hydrolysis resistance to the elastomer and to improve the strength under weak acid and weak alkalinity. It is possible to improve the flexibility and change the flexibility by adjusting the amount of the polyol. In this case, the adhesiveness is not sacrificed. In addition, stable non-yellowing can be ensured by selecting a non-aromatic diisocyanate, and the use of the above-mentioned polyol can reduce the pollution which is necessary because a part of the hydrophilicity in the elastomer can be made hydrophobic. It also has the benefit of not being discolored by. And when forming a multilayer structure using an elastomer, the reaction quiescent state is created by adjusting the NCO ratio, and the terminal or side chain is formed.
Since it can be chemically and strongly bonded to another layer-forming prepolymer having an OH group or an NH ₂ group and can be carried out by a casting method, it is very advantageous in terms of the method.

(Example) (Example 1) a) Polyol ... Polycarbonate polyol [trademark Desmophen manufactured by Bayer, product number # 2020] 50 parts Polybutadiene diol [manufactured by Idemitsu Petroleum] 50 parts b) Diisocyanate ... Isophorone diisocyanate (IPDI) ) 23 parts c) Crosslinking agent ... 1.4 Butanediol 2.5 parts d) Pigment ... 1 part (Example 2) a) Polyol ... Desmophen, product number # 2020 100 parts b) Diisocyanate ... (IPDI) 23 parts c) Crosslinking agent ... Methylene bis ortho chloroaniline (MOCA) 10 parts d) Pigment ... 1 part (Example 3) a) Polyol ... Desmophen, product number # 2020 100 parts b) Diisocyanate ... IPDI 30 parts c) Crosslinking agent ... MOCA 20 Part d) Pigment: 1 part (Example 4) a) Polyol: Desmophen, product number # 2020 100 parts b) Diisocyanate: IPDI 45 parts c) Crosslinking agent: MOCA 37.5 parts d) Pigment: 1 part (physical properties 1) ( Fruit Examples 1 to 4) and the physical properties compared with the other materials shown in (Table 1).

(Physical Properties 2) (b) in in an organic acid change in hardness ... organic acids below, i.e. _{CH 3 COOH: C 2 H 5} COOH: CH 3 (CH 2) 4 COO
H: C ₃ H ₇ COOH: H ₂ O = 5: 2: 2: 1: 90 (weight%) The time and hardness change (Shore value) (Example 3) and comparative example (indicated in the figure) ) Is shown in FIG.

(B) Change in 100% modulus ... The time of immersion in the same organic acid as in (a) and the change in 100% modulus are shown in FIG. 2 by taking (Example 3) and a comparative example.

(C) Change in tensile strength ... The time of immersion in the same organic acid as in (A) and the change in tensile strength are shown in FIG. 3 by taking (Example 3) and a comparative example.

(D) Volume change: The time and volume change immersed in the same organic acid as in (a) were changed (Example 3) and Comparative Example 4
Shown in the figure.

(Effect of the invention) From (i) (Table 1), the elastomer of the present invention can be expanded by proportioning the amount of polyol compounded and the amount of diisocyanate compounded.
160 ~ 20, tensile elastic modulus 400 ~ 1,400, compressive strength 4
A polyurethane elastomer capable of adjusting performance from a soft range to a hard range, which is 00 to 1,200, flexural strength of 25 to 140, and is non-destructive against impact, is obtained.

(Ii) As shown in Fig. 1, the change in hardness in organic acid shows a behavior almost similar to that of the fluorine-based soft lining material.

(Iii) As shown in FIG. 2, according to the present invention, 100% modulus change in organic acid is very small.

(Iv) From FIG. 3, the change in tensile strength in organic acid is very small.

(V) From FIG. 4, the volume change in the organic acid can be suppressed to a swelling level almost equal to that of the crepeto.

As can be seen from the above results, the polyurethane elastomer of the present invention has the necessary properties as a dental material which could not be realized by the conventional method. And while allowing various molecular designs by appropriately distributing the soft and rigid properties by arbitrarily combining the polyol, which is the soft segment of polyurethane, and the diisocyanate, which is the hard segment, a polyurethane elastomer member with rigidity and a flexible It is possible to realize a functional composite structure by stacking the elastomer having a high elasticity or the polyurethane elastomer and another material in a state where they have a high chemical bond with each other. Furthermore, this polyurethane elastomer is not only molded by itself but also of the same polyurethane elastomer but with different performance, even when forming a composite structure with other polyurethane or other prepolymer, it is possible to perform cast molding in any case etc. ... The method of the present invention brings a great gospel to the dental technician.

[Brief description of drawings]

1 to 4 are graphs showing various performances of the polyurethane elastomer of the present invention under immersion in an organic acid together with comparative examples.
FIG. 1 shows hardness change, FIG. 2 shows 100% modulus change, FIG. 3 shows tensile strength change, and FIG. 4 shows volume change. FIG. 5 is an explanatory view showing a procedure for forming a dental multilayer structure according to the present invention. (Explanation of symbols) 1 ... Denture, 2 ... Container, 3 ... Crosslinking agent, 4 ... Container, 5 ... Crosslinking agent, 10 ... Front tooth portion, 11 ... Main body portion, 20,2
1 …… Prepolymer, A, A ′, B …… Mold.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroki Wada 3-12-3 Yamate-cho, Suita-shi, Osaka (72) Inventor Tsukiji Koji 5-16 Gogo-cho, Nishinomiya-shi, Hyogo (72) Inventor Ikuya Matsuo 2-318-82 Shiomigaoka, Nakago, Ibaraki, Ibaraki Prefecture

Claims (2)

[Claims] 1. When forming a dental structure such as a denture base, a denture maintenance structure, a mouthpiece, an orthodontic device, etc. with a polyurethane elastomer, a single unit is provided to impart a function close to that of a natural tooth structure to these structures. Of a polycarbonate polyol, which is a method of chemically affinitizing at least a primary structure and a secondary structure having specific properties necessary for fulfilling their functions instead of forming a different structure. At least one polyol selected from polybutadiene polyol and polysiloxane diol,
Non-aromatic diisocyanate is used with at least one cross-linking agent selected from methylene bis-ortho-chloroaniline, 1.4-butanediol and trimethylol propane. To obtain the above-mentioned primary structure by pouring the prepolymer into a mold so as to be in a state, and to use the same polyol, diisocyanate and crosslinking agent as the above-mentioned prepolymer. OH group or NH ₂ at the terminal or side chain
Another polyurethane prepolymer having a group that reacts with the unreacted terminal isocyanate groups of the prepolymer is cast into the mold so that it is in contact with the primary structure to form the secondary structure. A method for forming a dental functional composite structure, which comprises forming a composite into a primary structure. 2. A polyol, polyamine or alkanolamine is added so that the NCO / NH ₂ or OH of the prepolymers forming the primary structure and the secondary structure have different NCO ratios within the range of 1.05 to 1.25. A method according to claim 1, comprising admixing each polyurethane prepolymer as a chain extender.