Medical Resin Composition, Process For Producing Resin Composition and Process For Producing Molded Article

a technology of resin composition and molded article, which is applied in the field of medical resin composition, can solve the problems of adversely stimulating an oral cavity, affecting the function of the oral cavity, and affecting the fit between the mucosal surface and the denture base, and achieves the effects of reducing the adverse effect of the human body, preventing the leaching of irritative substances, and facilitating the use of human bodies

Inactive Publication Date: 2008-08-21
UNIV OKAYAMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0016] The resin composition of the present invention can be used safely for the human body, especially in an oral cavity, because it inhibits leaching of irritative substances and it reduces any adverse effects on the human body by endocrine disruptors, etc. Further, it exhibits a high operational efficiency because a rate of viscosity increase during mixing of a powder and a liquid can be set within a proper range. Moreover, it is also possible to perform a crosslinking reaction according to demand. It therefore is easy to further reduce leaching components from the resin composition and to obtain molded articles with moderate hardness.

Problems solved by technology

Use of a denture for a long period of time will cause absorption of an alveolar ridge and fit between a mucosal surface of a denture and the mucosal surface in contact with the denture base gradually deteriorates.
As a result, application of a local excess pressure to the mucosal surface in contact with the base develops an abnormal condition in the mucous membrane in contact with the denture base or the alveolar ridge.
Ethanol, which is added for increasing a swelling speed of a poly(alkyl(meth)acrylate) when mixing a powder and a liquid, adversely gives stimulation to an oral cavity or leaches into saliva.
Ethanol may also cause problems such as deterioration in physical properties of a denture base or deformation thereof because it exhibits swellability also to a denture base in contact.
However, phthalates and the like are endocrine disruptors, and in other aromatic carboxylate, there are fears of effects on living bodies.
However, use of an acid ester-based plasticizer unfortunately leads to deterioration in workability due to a low swelling speed of a poly(alkyl(meth)acrylate).
Further, because an acrylic monomer is used, stimulation by the monomer to an oral cavity often becomes a problem.
It, however, is necessary to harden the material by use of heat, UV rays or the like and therefore it is often unsuitable for taking an impression in an oral cavity.
In a case of installation into an oral cavity, however, use of a volatile monomer is undesirable from the safety viewpoint.

Method used

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  • Medical Resin Composition, Process For Producing Resin Composition and Process For Producing Molded Article
  • Medical Resin Composition, Process For Producing Resin Composition and Process For Producing Molded Article
  • Medical Resin Composition, Process For Producing Resin Composition and Process For Producing Molded Article

Examples

Experimental program
Comparison scheme
Effect test

example 1

Spreading Test

[0062] A spreading test was conducted in accordance with the above-mentioned method by using 2 g of a powder of poly(ethyl methacrylate) (PEMA) having an average particle diameter of about 40 μm as a powder comprising polymer (A) and 1.8 mL of liquids comprising various vinyl ester monomers (B) shown below containing 1% by weight of benzoyl peroxide (C: polymerization initiator) as a liquid. A weight average molecular weight of the PEMA measured by gel permeation chromatography (GPC) is about 400,000. The mixture of dibutyl phthalate and 15% by weight of ethanol (Standard) corresponds to the recipe of tissue conditioners, which are commercially available at present. If the result of a spreading test is the same as or close to that of the mixture, it serves as a standard for judging that the operativity in use as a tissue conditioner is good.

[Linear Alkyl Vinyl Esters]

[0063] Vinyl caprylate (VO: n=10: molecular weight 170.25)

[0064] Vinyl caprate (VD: n=12: molecular...

example 2

Rubber Hardness Test

[0087] A Shore C hardness was measured in accordance with the above-mentioned method by using 6 g of a powder of poly(ethyl methacrylate) (PEMA) the same as that of Example 1 as a powder of polymer (A) and 5 mL of liquids comprising various vinyl ester monomers (B) shown below containing 1% by weight of benzoyl peroxide (C: polymerization initiator) as a liquid.

[Linear Alkyl Vinyl Ester]

[0088] Vinyl caprylate (VO: n=10: molecular weight 170.25)

[Cycloalkyl Vinyl Ester]

[0089] Vinyl cyclohexanecarboxylate (VCHC: n=9: molecular weight 154.21)

[Aromatic Vinyl Esters]

[0090] Vinyl p-methylbenzoate (VMB: n=10: molecular weight 162.19)

[0091] Vinyl cinnamate (VC: n=11: molecular weight 174.2)

[Divinyl Esters]

[0092] Divinyl adipate (DVA: n=10: molecular weight 198.22)

[Other Liquids]

[0093] Mixture of dibutyl phthalate (n=16: molecular weight 278.35) and 15% by weight of ethanol (Standard)

[0094]FIG. 6 is a graph produced by plotting Shore C hardnesses as ordinate a...

example 3

Polymerization Test

[0095] 2 g of a powder of a methyl methacrylate (MMA: 40% by weight)-ethyl methacrylate (EMA: 60% by weight) copolymer having an average particle diameter of about 50 μm and 1 g of divinyl adipate (DVA) containing 1% by weight of benzoyl peroxide were mixed and then stirred for 30 seconds. A weight average molecular weight of the MMA-EMA copolymer measured by GPC was about 500,000. The resulting mixture was fed into a mold which can produce a specimen with dimensions 2 mm×2 mm×25 mm and was held at 100° C. for 10 min under a load of 3 ton. Thus, a polymerization reaction was allowed to proceed. After spontaneous cooling, the specimen taken out from the mold was left at rest in the air for one day and then was subjected to a three-point bending test (span: 20 mm, cross-head speed: 0.5 mm / min) with a universal testing machine (INSTRON 5544). Thus, flexural strength, flexural modulus, fracture energy and maximum deflection were measured. Further, samples before and ...

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Abstract

A medical resin composition is produced by mixing a powder of a polymer (A) comprising repeating units having an ester group and a liquid of a vinyl ester monomer (B) having 6 or more carbon atoms to increase a viscosity and, according to demand, further performing a polymerization reaction. The thus produced resin composition inhibits leaching of irritative substances, reduces any adverse effects on the human body by endocrine disruptors, etc. and can be prepared with high operational efficiency. The resin composition is suitably used as a dental resin composition such as a tissue conditioner, a functional impression material, a lining material, a denture base material or a mouth piece material.

Description

TECHNICAL FIELD [0001] The present invention relates to medical resin compositions, especially dental resin compositions, comprising a polymer comprising repeating units having an ester group and a vinyl ester monomer. It relates also to processes for producing resin compositions and processes for producing molded articles. BACKGROUND ART [0002] Use of a denture for a long period of time will cause absorption of an alveolar ridge and fit between a mucosal surface of a denture and the mucosal surface in contact with the denture base gradually deteriorates. As a result, application of a local excess pressure to the mucosal surface in contact with the base develops an abnormal condition in the mucous membrane in contact with the denture base or the alveolar ridge. When the mucous membrane in contact with a denture base or the alveolar ridge has something wrong, it is recovered to a normal condition by lining the mucosal surface of the denture with a tissue conditioner or the like, whic...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C08F118/02
CPCA61C13/0024A61C13/0025A61K6/10C08L31/06
Inventor TANAKA, JIROSUZUKI, KAZUOMI
Owner UNIV OKAYAMA
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