WO2022255050A1 - 鋳型作製用石膏組成物 - Google Patents

鋳型作製用石膏組成物 Download PDF

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Publication number
WO2022255050A1
WO2022255050A1 PCT/JP2022/019938 JP2022019938W WO2022255050A1 WO 2022255050 A1 WO2022255050 A1 WO 2022255050A1 JP 2022019938 W JP2022019938 W JP 2022019938W WO 2022255050 A1 WO2022255050 A1 WO 2022255050A1
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Prior art keywords
gypsum
mold
composition
hemihydrate
gypsum composition
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
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PCT/JP2022/019938
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English (en)
French (fr)
Japanese (ja)
Inventor
璃奈 小原
達矢 堀内
絵美 亀田
成泰 熊谷
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Yoshino Gypsum Co Ltd
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Yoshino Gypsum Co Ltd
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Publication date
Application filed by Yoshino Gypsum Co Ltd filed Critical Yoshino Gypsum Co Ltd
Priority to CN202280039153.XA priority Critical patent/CN117412733A/zh
Priority to US18/547,782 priority patent/US20240140872A1/en
Priority to KR1020237043648A priority patent/KR20240009489A/ko
Priority to JP2023525691A priority patent/JPWO2022255050A1/ja
Publication of WO2022255050A1 publication Critical patent/WO2022255050A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C13/00—Dental prostheses; Making same
    • A61C13/01—Palates or other bases or supports for the artificial teeth; Making same
    • A61C13/02—Palates or other bases or supports for the artificial teeth; Making same made by galvanoplastic methods or by plating; Surface treatment; Enamelling; Perfuming; Making antiseptic
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C13/00—Dental prostheses; Making same
    • A61C13/01—Palates or other bases or supports for the artificial teeth; Making same
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C13/00—Dental prostheses; Making same
    • A61C13/10—Fastening of artificial teeth to denture palates or the like
    • A61C13/1003—Fastening of artificial teeth to denture palates or the like by embedding in base material
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C13/00—Dental prostheses; Making same
    • A61C13/20—Methods or devices for soldering, casting, moulding or melting
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C13/00—Dental prostheses; Making same
    • A61C13/34—Making or working of models, e.g. preliminary castings, trial dentures; Dowel pins [4]
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/15—Compositions characterised by their physical properties
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/80—Preparations for artificial teeth, for filling teeth or for capping teeth
    • A61K6/849—Preparations for artificial teeth, for filling teeth or for capping teeth comprising inorganic cements
    • A61K6/858—Calcium sulfates, e.g, gypsum
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
    • C04B28/145—Calcium sulfate hemi-hydrate with a specific crystal form
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
    • C04B28/145—Calcium sulfate hemi-hydrate with a specific crystal form
    • C04B28/147—Calcium sulfate hemi-hydrate with a specific crystal form beta-hemihydrate
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
    • C04B40/0028—Aspects relating to the mixing step of the mortar preparation
    • C04B40/0032—Controlling the process of mixing, e.g. adding ingredients in a quantity depending on a measured or desired value
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
    • C04B2103/30—Water reducers, plasticisers, air-entrainers, flow improvers
    • C04B2103/302—Water reducers
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00836—Uses not provided for elsewhere in C04B2111/00 for medical or dental applications
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00939—Uses not provided for elsewhere in C04B2111/00 for the fabrication of moulds or cores

Definitions

  • the present invention relates to a gypsum composition for making a gypsum mold used when making a model, and for example, to a gypsum composition for making a mold suitable for making models such as dentures (dentures). More specifically, since the slurry-like kneaded product to which water is added exhibits good fluidity, it is possible to improve the workability when producing a mold (gypsum mold), and when hardened, the gypsum is removed.
  • the present invention relates to a gypsum composition for making molds, which can form molds in good condition in which the occurrence of cracks is suppressed.
  • Gypsum compositions are used as gypsum molds (molds) when making various models, and have the property of being able to faithfully reverse the fine pattern of the model and to obtain an extremely smooth plane.
  • a model that requires such characteristics is a so-called denture.
  • the gypsum composition which is a useful material for making a mold that is necessary for making a model that has a different shape for each model and requires high precision, such as dentures, is also in good condition. It is required to have properties that enable the production of molds, so-called gypsum molds, with better workability and more stability.
  • a mold obtained from the gypsum composition is hereinafter also referred to as a gypsum mold.
  • the surface condition of the gingiva (gums) formed by pouring resin into the cavity (space) of the resulting mold and hardening it depends on the condition of the inner surface of the cavity of the gypsum mold used. In order to make a better fitting "denture”, the following are required as basic performance. In other words, when the dentures are put in the mouth, the artificial teeth must be fixed and held in the artificial gingiva (gums) so that they are in a good occlusion state. ) is required to have a surface condition that does not give a sense of discomfort to a user wearing dentures.
  • Patent Literature 1 proposes a resin material for dentures formed using the mold. It is also important for denture manufacturers to supply well-fitting dentures as quickly as possible. In this respect, it is particularly desired to improve the work efficiency of dental technicians when making dentures (models), and if the work efficiency can be improved, it will be beneficial for users of dentures.
  • an object of the present invention is to contribute to improvement of workability in the process of producing molds, which are required for producing resinous artificial gingiva (gums) parts, etc., which are individually different and require precise shapes. It is an object of the present invention to provide a gypsum composition for making molds.
  • the present invention provides the following gypsum composition for mold preparation.
  • a gypsum for making molds which contains gypsum hemihydrate, and the gypsum hemihydrate contains ⁇ -type gypsum hemihydrate and ⁇ -type gypsum hemihydrate in a ratio of 25:75 to 65:35. Composition.
  • Preferred embodiments of the gypsum composition for making molds of the present invention include the following inventions.
  • the pot life of the slurry kneaded mixture obtained by adding water to a mixing amount of 45% and kneading is adjusted to 8 minutes or more, and the curing time is adjusted to 30 minutes or less.
  • a gypsum composition for making molds (hereinafter referred to as a gypsum composition for molds).
  • FIG. 1 is a schematic cross-sectional view showing the state inside a polymerization flask 10 for explaining the situation in which the gypsum composition for molding of the present invention is used.
  • FIG. The inside of the flask for polymerization is supported by a plaster model (hereinafter also referred to as a "working model") 3 that simulates the patient's oral cavity, which is prepared by pouring gypsum into an impression of the patient taken at a dental clinic or the like.
  • a wax denture having an artificial tooth 2b and a wax rim 2a" 2 must be embedded in the gypsum composition without gaps.
  • FIG. 1 is a schematic perspective view for explaining a state in which the wax denture 2 is arranged.
  • FIG. 1 The operation of embedding the "wax denture having an artificial tooth and a wax ridge" 2 placed in the lower container 5a constituting the polymerization flask shown in FIG. It is a typical perspective view for explaining the state in which it is performed.
  • FIG. 1 is a schematic perspective view for explaining a state in which the wax denture 2 is arranged.
  • FIG. 2 is a schematic perspective view of an example of a polymerization flask used in the mold preparation process, the interior of which must be in the state shown in FIG. 1 in the mold preparation process. That is, when the upper member 5b serving as a lid is placed on the lower container 5a of the polymerization flask, the inside of the polymerization flask 10 must be filled with the gypsum composition without voids.
  • a description will be given of how a slurry-like kneaded product 1 obtained by adding water to the gypsum composition for a casting mold of the present invention is poured into the voids not filled with the gypsum composition formed in the polymerization flask in the state shown in FIG. It is a typical perspective view for doing.
  • a wax denture having an artificial tooth and a wax ridge is produced as follows, and then a gypsum mold for producing a resin artificial gingiva (gums) is produced using the wax denture. do.
  • the gypsum composition for casting molds of the present invention is used in the portion where gypsum is not filled in the polymerization flask during the preparation of the casting mold, and as a result, the workability of the manufacturing process of "dentures" is improved. contribute effectively to The following explanation is an example using a polymerization flask 10 having a structure that is divided into upper and lower parts as shown in FIGS. That is, as shown in the figure, a polymerization flask was used which was composed of a lower member 5a serving as a container and an upper member 5b serving as a lid (also referred to as lid 5b or lid).
  • the wax rim 2a is provided on the working model 3, and the artificial tooth 2b is placed at a position of the wax rim that allows the user of the dentures to achieve good occlusion (see FIG. 1).
  • the wax bank is made of a material such as wax that melts in a microwave oven or hot water.
  • the surface portion of the wax rim 2a serving as a base for supporting the artificial tooth 2b is engraved to reproduce the gingiva (gums) portion with good appearance. In this way, a "wax denture having an artificial tooth 2b and a wax rim 2a" 2 is produced.
  • the "wax denture having an artificial tooth and a wax ridge" 2 obtained as described above is placed under the polymerization flask 10 having a structure that is divided into upper and lower parts as described above. It is fixed in the container 5a using the gypsum composition 4 for primary burial. This operation is called "primary burial”.
  • a gypsum composition 6 for secondary burial is placed on the “wax denture having an artificial tooth and a wax rim” 2 after primary burial, which is obtained as described above. It covers the ridge 2a and the artificial tooth 2b. This operation is called "secondary burial”.
  • the polymerization flask is covered with an upper lid 5b, and then a slurry mixture of the gypsum composition for molding of the present invention and water is poured into the polymerization flask 10, and The "wax denture having an artificial tooth and a wax ridge" 2 is embedded in the gypsum composition by filling the voids in the gypsum composition. This operation is called “tertiary burial”.
  • the "wax denture having the artificial tooth 2b and the wax rim 2a" 2 may be simply referred to as the "wax denture 2".
  • the slurry-like kneaded product to which water is added exhibits good fluidity in the tertiary embedding operation when obtaining the mold for forming the artificial gingiva.
  • the gypsum composition for molding it is possible to obtain resin-made artificial gingiva (gums) in good condition with good workability.
  • the procedure for producing the artificial gingiva (gums) portion of the wax denture 2 from resin using a mold (gypsum mold) for forming artificial gingiva is as follows.
  • the wax (wax) constituting the artificial gingiva (gums) portion of the wax denture 2 Tsutsumi 2a) is sufficiently melted out using a microwave oven or hot water to form a hollow mold (gypsum mold) in which the wax portion is melted.
  • gypsum mold a hollow mold in which the wax portion is melted.
  • the artificial tooth 2b held in place by the wax before being melted is held in place by the hardened gypsum.
  • the state of the sculpted gingiva (gum) is transferred to the inner surface of the cavity formed by the flow of the melted wax, where the wax has been removed.
  • this gypsum mold is filled with resin for forming artificial gingiva, and the resin is allowed to harden.
  • the mold is split to remove the resin-made artificial gingiva (gums) and the artificial teeth firmly fixed and supported by the artificial gingiva, and then the artificial teeth and the artificial gingiva are carefully separated. Polish to As a result, a "denture" is obtained in which the artificial teeth are arranged in good condition as the occlusion is adjusted in the artificial gingiva (gums) made of resin.
  • the present inventors improved the gypsum composition for casting molds and used it for the following operations that have the following problems, thereby improving workability. It was found that the improvement of In the process of filling resin into a mold in which the wax portion has melted and a cavity has been formed, the resin is usually injected by applying pressure into the cavity left behind after the wax has been removed, in order to fill the mold with dense resin. It is For this reason, cracks and splits occur in the hardened gypsum composition used in secondary burial, and the cracks become burrs. be. In addition, at this time, conventional gypsum compositions used for tertiary burial have poor fluidity when mixed with water. , it was necessary to vibrate with a vibrator and fill the gypsum composition for tertiary burial carefully so as not to create voids in the polymerization flask.
  • the hardened body of the gypsum composition for casting molds of the present invention used in the tertiary investment cooperates with the hardened body of the gypsum composition used in the secondary investment to form a resin It has a surprising effect of exhibiting sufficient strength to suppress cracks and cracks caused by pressure during injection.
  • the polymerization flask 10 used in the above process has various shapes, and is not limited to the one that can be divided into two as exemplified above. However, in any structure, as described above, it is necessary to finally take out the hardened gypsum from the polymerization flask filled with gypsum, and then break the gypsum to take out the dentures. As schematically shown in FIG. 3, it has a structure divided into upper and lower parts. Then, as shown in FIGS. 2A and 2B, the "artificial tooth and artificial gingiva (gums)" are placed in the lower container 5a that serves as a vessel for polymerization flask and are fixed by the gypsum composition 4 for primary embedding.
  • the "artificial tooth and artificial gingiva (gums)" are placed in the lower container 5a that serves as a vessel for polymerization flask and are fixed by the gypsum composition 4 for primary embedding.
  • the upper member 5b functioning as a lid of this container is superimposed on the lower container 5a of the polymerization flask 10, and integrated as shown in FIG. 3, after which the gypsum composition is cured. is done.
  • the upper member 5b serving as the lid is superimposed and integrated with the container 5a of the polymerization flask, it is integrated into the polymerization flask 10, although there is a difference in size.
  • An unfilled void portion, which is not filled with gypsum, is formed after drying. For this reason, it is necessary to carry out a tertiary embedding operation to fill the gypsum composition into the voids. Specifically, for example, as shown in FIG.
  • a gypsum composition with high viscosity adjusted for tertiary burial is slowly and carefully applied over time using a vibrator or the like so as not to create unfilled voids. Filling the gypsum composition to fill the inside of the polymerization flask with the gypsum composition is performed.
  • the "wax denture having the artificial tooth 2b and the wax rim 2a" 2 is carefully buried in the gypsum composition without voids, and then the gypsum is cured. After hardening, a hardened gypsum body for making a mold in which the wax denture 2 is embedded in the gypsum composition is taken out from the polymerization flask 10 .
  • the inventors of the present invention have found that the workability of the dental technician is impaired in the process of manufacturing the denture mold described above because the structure of the polymerization flask inevitably results in the unfilled gypsum generated in the polymerization flask. It was recognized that it was in the filling process (tertiary burial) of the gypsum composition into the "void of the
  • a gypsum composition with the following characteristics can be developed to address the above technical issues, it will be extremely useful in terms of work. Specifically, the gypsum composition can be quickly and easily filled into the voids generated in the polymerization flask for tertiary burial in a good state, and the slurry-like kneaded product has excellent fluidity.
  • a gypsum composition for manufacturing molds that does not generate burrs in a resin part that will be an artificial gingiva (gums) formed using a mold (gypsum mold) having a cavity left after the wax wall 2a is removed. Development of things is desired.
  • the inventors of the present invention have made intensive studies to develop a gypsum composition capable of exhibiting the above-described characteristics in order to solve the technical problems associated with the production of molds in the process of producing dentures, and as a result, have arrived at the present invention.
  • the gypsum composition for manufacturing molds of the present invention contains gypsum hemihydrate, and the gypsum hemihydrate contains ⁇ -type gypsum hemihydrate and ⁇ -type gypsum hemihydrate in a ratio of 25:75 to 65:35. characterized by comprising
  • the gypsum composition Water is added to the gypsum composition for a casting mold having the above structure to form a slurry, and when the gypsum composition is filled into the gypsum-unfilled voids generated in the polymerization flask for tertiary embedding, the gypsum composition has an appropriate fluidity. Therefore, the dense gypsum composition can be quickly and easily filled into the voids in the polymerization flask. Therefore, the work efficiency in producing a mold (gypsum mold) for producing resin artificial gingiva (gums) is significantly improved.
  • the following excellent effects can be obtained by filling the gypsum composition for molding of the present invention into the polymerization flask by tertiary burial as described above.
  • the following operations are performed in the process of producing a mold (gypsum mold) for producing an artificial gingiva (gums).
  • the gypsum is sufficiently hardened and the wax (wax bank) is melted out to form a cavity to complete a mold (gypsum mold).
  • the cavities are filled with resin that will become artificial gingiva (gums).
  • the mold having the model (denture) obtained as described above is composed of the gypsum composition for molding of the present invention used for the tertiary burial and the secondary burial for embedding the wax denture performed before the tertiary burial. Then, it will be in a state of being integrated without any problem with the highly viscous gypsum composition previously filled in the polymerization flask.
  • the gypsum composition for casting of the present invention used for tertiary burying and the gypsum composition used for secondary burying work together.
  • the artificial gingiva (gums) made of resin that constitutes the "denture”, which is taken out by breaking the mold is in good condition without any burrs caused by cracks. Therefore, the need for post-processing such as removal of burrs can be reduced.
  • the mold after curing of the resin can be broken without any problem. Then, by carefully removing the gypsum adhering to the artificial teeth, etc., it is possible to finally obtain the "dentures" in good condition.
  • the materials for forming the gypsum composition for molding of the present invention which can provide the excellent effects described above, will be described below.
  • the gypsum composition for casting molds of the present invention is used for the applications as exemplified above, and is not used for manufacturing casting molds (gypsum molds) for casting metals. Therefore, since refractory properties and high heat resistance are not required, the refractory materials such as cristobalite and quartz are not included.
  • the model requiring a mold is described as a "denture", but its application is not limited to the "denture”.
  • the gypsum composition for molding of the present invention can also be widely used in the process of producing molds used for producing resin models and the like for various purposes. By using the gypsum composition for casting molds of the present invention, it is possible to efficiently obtain various types of models having minute shapes with reduced generation of burrs.
  • the gypsum composition for molding of the present invention is provided in the form of a powder, and is made into a slurry-like kneaded product by adding water at the time of use.
  • "Powder” as used in the present invention means that the average particle size is 200 ⁇ m or less.
  • the average particle size in this specification means the particle size at the median diameter (d 50 ) in the particle size distribution measurement determined by the laser diffraction/scattering method.
  • the average particle size of the gypsum composition for molding in the present invention can be measured using a laser diffraction particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., trade name: Microtrac HRA).
  • the foundry gypsum composition of the present invention comprises gypsum hemihydrate. Specifically, 1/2 hydrate of calcium sulfate (CaSO 4 .1/2 H 2 O) is called gypsum hemihydrate. Since gypsum hemihydrate reacts with water and changes to gypsum dihydrate, a gypsum slurry prepared by kneading gypsum hemihydrate and water hardens quickly when poured into a polymerization flask. For this reason, it is widely used for making molds. Gypsum hemihydrate is obtained by firing gypsum dihydrate (calcium sulfate dihydrate).
  • Examples of gypsum dihydrate used as a raw material in this case include natural gypsum, by-product gypsum, and recycled gypsum obtained through a recycling process of gypsum products.
  • the hemihydrate gypsum constituting the gypsum composition for casting molds of the present invention may be obtained from any of the raw materials of gypsum dihydrate described above.
  • the amount of gypsum hemihydrate in the gypsum composition for molding of the present invention can be, for example, 95 parts by weight or more in 100 parts by weight of the gypsum composition for molding. More preferably, it can be 98 parts by mass or more.
  • the gypsum composition for molding of the present invention contains the above-described gypsum hemihydrate, and the composition of the gypsum hemihydrate is composed of ⁇ -type gypsum hemihydrate and ⁇ -type gypsum hemihydrate in a ratio of 25:75 to 65:35. It is characterized in that it is configured to include As a preferred form of the gypsum composition for molding of the present invention, the ratio of ⁇ -type hemihydrate gypsum to ⁇ -type hemihydrate gypsum is 25:75 to 60:40.
  • the ratio of ⁇ -hemihydrate gypsum to ⁇ -hemihydrate gypsum is 30:70 to 60:40.
  • the average particle size of these hemihydrate gypsum is preferably about 10 to 80 ⁇ m, more preferably about 20 to 50 ⁇ m.
  • the ⁇ -hemihydrate gypsum and ⁇ -hemihydrate gypsum essential in the gypsum composition for molding of the present invention are described below. As will be described later, the gypsum composition for molding of the present invention is considered to have the effect of the present invention that has not been achieved by the above-described composition of gypsum hemihydrate.
  • ⁇ -type hemihydrate gypsum can be obtained by pressurizing and calcining the raw material gypsum dihydrate described above in water or steam.
  • ⁇ -type hemihydrate gypsum can be kneaded with a smaller amount of water (that is, a lower amount of water) than ⁇ -type hemihydrate gypsum, which will be described later. Therefore, the gypsum hardened body obtained using the ⁇ -type hemihydrate gypsum has high strength (compressive strength).
  • the ⁇ -type hemihydrate gypsum used in the present invention preferably has an average particle size of about 10 to 80 ⁇ m, more preferably about 20 to 50 ⁇ m.
  • ⁇ -type hemihydrate gypsum ( ⁇ -type hemihydrate gypsum) ⁇ -type hemihydrate gypsum is obtained by calcining the raw material gypsum dihydrate described above in the air. Compared to the ⁇ -type hemihydrate gypsum, it is necessary to increase the amount of water mixed for kneading. Therefore, the gypsum hardened body obtained using ⁇ -type hemihydrate gypsum has a low strength (compressive strength).
  • the gypsum hardened body obtained using ⁇ -type hemihydrate gypsum is ⁇ -type It has a higher strength than a gypsum hardened body obtained using hemihydrate gypsum.
  • the ⁇ -type hemihydrate gypsum used in the present invention preferably has an average particle size of about 10 to 80 ⁇ m, more preferably about 20 to 50 ⁇ m.
  • ⁇ -type hemihydrate gypsum is the main raw material used in the gypsum composition for making molds used when making "dentures".
  • the reason why ⁇ -type hemihydrate gypsum is not used as a raw material is as follows. In order to obtain the dentures embedded in the mold, it is finally necessary to break the mold (hardened gypsum) and take out the dentures.
  • the hardened gypsum is too strong to be broken, and if it is broken forcibly, the dentures embedded in the mold will be damaged. There is also concern about damage.
  • the present inventors have found that, as described above, the gypsum composition can be quickly and easily filled into the voids generated in the polymerization flask due to its structure and the like. It was recognized that it is important to improve the workability in manufacturing "dentures".
  • a special device such as a press fit or a vibrator is used as a means for filling the unfilled voids of the gypsum composition generated in the polymerization flask.
  • the present inventors conducted intensive studies, and found that the composition of the gypsum hemihydrate raw material constituting the gypsum composition for casting molds was determined to be ⁇ -hemihydrate gypsum and ⁇ -type semihydrate gypsum, The present inventors have found that it is possible to provide a gypsum composition for molding that can achieve the above-described object by a very simple means of containing hydrogypsum and hydrogypsum in a ratio of 25:75 to 65:35.
  • ⁇ -type hemihydrate gypsum and ⁇ -type hemihydrate gypsum are used within the range of the ratio specified in the present invention, water is added to the powder material and, for example, by making a slurry with a water mixture amount of 45%, It is possible to improve the fluidity of the gypsum composition, thereby making it possible to fill the gypsum composition into voids (spaces) that are not filled with gypsum and that occur in the polymerization flask due to the structure of the polymerization flask. , can be realized quickly and easily.
  • the gypsum composition for molding of the present invention since the slurry obtained using the gypsum composition for molding of the present invention exhibits good fluidity, the risk of inclusion of air bubbles during kneading is extremely low, and an antifoaming agent is not required. Alternatively, even if it is added, the amount of antifoaming agent can be significantly reduced. Therefore, the gypsum composition for molding of the present invention is industrially useful in terms of raw material costs, which is another effect.
  • the kneaded product of the gypsum composition for molding of the present invention having the above configuration and water becomes useful with the following characteristics even when kneaded with a small amount of water.
  • the kneaded product has a low viscosity and excellent fluidity, and the gypsum hardened body obtained has a low strength (compressive strength).
  • the mold which is a hardened gypsum obtained using the gypsum composition for molding, is injected into the cavity with a resin that forms the artificial gingiva (gums) of the resin-made dentures, It has sufficient compressive strength to prevent cracking.
  • the mold can be broken without any problem, and the denture (model) inside can be taken out by breaking it.
  • the gypsum composition for molding of the present invention is integrated in a good state with the gypsum composition with high viscosity previously used for secondary investment, and the hardened body of the gypsum composition used for secondary investment has cracks. to prevent such occurrences. Therefore, a resin-made artificial gingiva (gums) obtained by supplying a resin for forming the gum portion into the cavity of the obtained mold and curing the resin is in good condition without burrs. Therefore, secondary processing after curing of the resin is facilitated, which is excellent in economic efficiency.
  • a resin-made artificial gingiva (gums) obtained by supplying a resin for forming the gum portion into the cavity of the obtained mold and curing the resin is in good condition without burrs. Therefore, secondary processing after curing of the resin is facilitated, which is excellent in economic efficiency.
  • the amount of the water reducing agent added is It can be made to be 0.02 to 0.2 parts by mass with respect to parts. That is, in the gypsum composition for molding of the present invention, even if the amount of the water reducing agent (dispersant) added is relatively small, such as 0.2 parts by mass or less, the effect of adding the water reducing agent can be obtained. For this reason, the gypsum composition for molding of the present invention can reduce the cost of raw materials in this respect as well, and is excellent in economic efficiency.
  • water reducing agent for example, a naphthalenesulfonic acid-based dispersant, a melamine-based dispersant, a polycarboxylic acid-based dispersant, and a phosphonic acid-based dispersant can be used.
  • a naphthalenesulfonic acid-based dispersant for example, a melamine-based dispersant, a polycarboxylic acid-based dispersant, and a phosphonic acid-based dispersant can be used.
  • any conventionally known water reducing agent (dispersant) can be used.
  • the foundry gypsum composition of the present invention may contain conventionally known additives as long as they do not impair the intended purpose.
  • a curing modifier such as a curing accelerator or a curing retarder can be added as appropriate.
  • hardening accelerators include gypsum dihydrate and potassium sulfate, and other general hardening accelerators can be used.
  • the hardening retarder for example, sodium citrate or the like, or other general hardening retarders can be used.
  • Examples 1 to 5 and Comparative Examples 1 and 2 Using the compositions shown in Table 1, gypsum compositions for molding of Examples 1 to 5 and Comparative Examples 1 and 2 were prepared. At the time of preparation, 0.03 parts of dihydrate gypsum and 0.2 parts of potassium sulfate as a setting accelerator and 0.025 parts of sodium citrate as a setting retarder are added to 100 parts of the gypsum composition for molding. and 0.025 parts of potassium tartrate as an expansion inhibitor were added under the same conditions. Furthermore, when the prepared composition is used for tertiary implantation in the manufacture of "dentures", in order to ensure good fluidity when poured into a flask for polymerization, the composition is adjusted so that the flow value below is obtained.
  • the operation of pouring a small amount of gypsum slurry every 30 seconds was repeated. Then, 30 seconds before the time when the viscosity of the gypsum slurry became high and it stopped flowing continuously (it fell like it was broken) was taken as the pourable time, the so-called "workable time". In order to secure the working time, which is the object of the present invention, it is necessary to secure a usable time of 8 minutes or more.
  • the compressive strength of the hardened gypsum obtained using the gypsum composition for molding to be measured was measured in accordance with JIS T6604 Dental Plaster of Paris-5.8 Compressive Strength Test. Specifically, it was measured according to the following procedure. ⁇ For the measurement of compressive strength, use a cylindrical mold with a height of 40 mm and an inner diameter of 20 mm, and five series of compressive strength molds. • Place a compressive strength mold coated with a release agent in the center of the glass plate. - Knead the gypsum composition for the mold to be measured, and add the gypsum slurry until it rises slightly above the edge of the mold for compressive strength on the glass plate.
  • the mold is gently shaken during pouring to minimize entrainment of air bubbles.
  • - 60 minutes after the start of kneading using a compressive strength tester, 5 specimens of gypsum hardened body for compressive strength measurement are subjected to a destructive test, and the maximum force (F) applied is recorded. Then, the compressive strength (S) was calculated by the following formula.
  • the mold obtained using the gypsum composition for molding is a hardened body of the gypsum composition used for secondary embedding when injecting the resin for forming the artificial gingiva (gums) of the resin-made dentures.
  • Compressive strength of "10 Mpa or more" was targeted as the strength of the hardened gypsum so that the gypsum would not crack.

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  • Health & Medical Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Ceramic Engineering (AREA)
  • Engineering & Computer Science (AREA)
  • Veterinary Medicine (AREA)
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  • Chemical Kinetics & Catalysis (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Plastic & Reconstructive Surgery (AREA)
  • Dental Preparations (AREA)
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  • Mold Materials And Core Materials (AREA)
PCT/JP2022/019938 2021-06-02 2022-05-11 鋳型作製用石膏組成物 Ceased WO2022255050A1 (ja)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62212255A (ja) * 1986-03-12 1987-09-18 而至歯科工業株式会社 低粉塵性粉末状歯科用石こう組成物
JPH03279248A (ja) * 1990-03-28 1991-12-10 Toubu Kagaku Kk 型材及び型取り方法
JPH1087419A (ja) * 1996-09-18 1998-04-07 G C:Kk 歯科用石こう組成物
JPH10226558A (ja) * 1997-02-10 1998-08-25 Sanesu Sekko Kk 歯科用焼セッコウ組成物
JP2004035323A (ja) * 2002-07-03 2004-02-05 Noritake Co Ltd 石膏型成形用材料並びに該材料から成る石膏型及びその製法
WO2016043131A1 (ja) * 2014-09-19 2016-03-24 株式会社ジーシー 歯科用石膏系埋没材粉末

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4838923A (en) * 1987-03-17 1989-06-13 Teijin Limited Organo-phosphorus compound and herbicide comprising it as active ingredient
NO302538B1 (no) * 1995-05-30 1998-03-16 Reslab As Framgangsmåte for stabilisering av ukonsolidert kjernemateriale fra borehull
WO2012077229A1 (ja) * 2010-12-10 2012-06-14 吉野石膏株式会社 乾燥石膏組成物及び石膏系上塗り塗材
JP7341427B2 (ja) 2019-06-11 2023-09-11 株式会社トクヤマデンタル 義歯床用ポリエステル樹脂、これを用いたノンメタルクラスプデンチャー及びその製造方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62212255A (ja) * 1986-03-12 1987-09-18 而至歯科工業株式会社 低粉塵性粉末状歯科用石こう組成物
JPH03279248A (ja) * 1990-03-28 1991-12-10 Toubu Kagaku Kk 型材及び型取り方法
JPH1087419A (ja) * 1996-09-18 1998-04-07 G C:Kk 歯科用石こう組成物
JPH10226558A (ja) * 1997-02-10 1998-08-25 Sanesu Sekko Kk 歯科用焼セッコウ組成物
JP2004035323A (ja) * 2002-07-03 2004-02-05 Noritake Co Ltd 石膏型成形用材料並びに該材料から成る石膏型及びその製法
WO2016043131A1 (ja) * 2014-09-19 2016-03-24 株式会社ジーシー 歯科用石膏系埋没材粉末

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