JPH10193762A - Impression material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an impression material in which generation of dust is retarded while suppressing permanent strain by comprising the impression material principally of alginate, calcium sulfate and/or lead silicate, and zinc oxide at a specified ratio and specifying the average grain size of zinc oxide. SOLUTION: Alginate includes sodium alginate, potassium alginate, and the like, and obtained by neutralizing an extraction from natural seaweed. Mixing ratio of calcium sulfide and/or lead silicate must be 5-500 pts.wt. for 100 pts.wt. of alginate and it is preferably set in the range of 50-200 pts.wt. Zinc oxide having average grain size of 0.2-2μm is employed. Mixing ratio of zinc oxide is 1-20 pts.wt. for 100 pts.wt. of alginate. A wetting agent for retarding generation of dust preferably occupy 0.05-1wt.% of the total weight. this composition suppresses permanent strain and retards generation of dust.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impression material used for molding teeth and other molds. In particular, it relates to an alginate impression material excellent in dust prevention.

2. Description of the Related Art An impression material mainly composed of a divalent metal salt such as alginate and calcium sulfate is called an alginate impression material or an alginate impression material. Used for
Alginate impression materials have characteristics such as good impression accuracy, reproducibility of fine parts, and easy impression operation, and are most often used as dental impression materials. Alginate impression materials are alginate and divalent metal salts such as calcium sulfate and all components such as fillers are mixed in powder form, and are mixed with water when taking impressions at dental clinics, etc. Used in paste form. In this alginate impression material, when the impression material is kneaded with water, the carboxyl group of alginic acid is cross-linked by divalent metal ions and gels to form a cured product having elasticity. The cured body of the impression material is of a negative type. Gypsum is poured into the impression body, and after the gypsum is hardened, the gypsum is removed from the cured body of the impression material to produce a model. By the way, since the alginate impression material is in the form of powder, when kneaded with water, the powder scatters into the air, pollutes the air, and deteriorates the working environment. In order to prevent the scattering of the powder, JP-A-57-501426 discloses a method of coating powder particles of an alginate impression material using a coating agent which easily and rapidly wets with water. In this method, natural polymer dispersants, cellulose esters or cellulose ethers, synthetic nonionic polymer surfactants, block copolymers of polysiloxanes and polyethylene glycols, polyols,
Alkanolamines, glycerol esters and the like are used.

By the way, it is known to add fine zinc oxide as a divalent metal salt to an impression material in order to harden the surface of the gypsum model and increase the elastic strain. I have. However, when this fine zinc oxide is added, the powder tends to be more easily scattered. Thus, an attempt was made to prevent the generation of dust by mixing the above coating agent. However, in order to prevent the generation of dust with the above-mentioned coating agent, a relatively large amount of coating agent must be used, so that the permanent distortion of the cured product becomes large, the accuracy of impression is reduced, and further long-term storage It was later found that the gel time was likely to be delayed. Therefore, an object of the present invention is to provide an alginate impression material that hardly generates dust and has a small permanent set.

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, by using zinc oxide of a specific average particle system, an alginate having a small amount of dust and a small permanent set has been obtained. The impression material was successfully obtained, and the present invention was completed. That is, the present invention provides an impression material containing 100 parts by weight of alginate, 5 to 500 parts by weight of calcium sulfate and / or lead silicate, and 1 to 20 parts by weight of zinc oxide. 2
An impression material characterized by having a thickness of about 2 μm.

DETAILED DESCRIPTION OF THE INVENTION The alginate used in the present invention is:
Known materials conventionally used for impression materials are used without any limitation. Specifically, sodium alginate,
And potassium alginate. These alginates are generally obtained by extracting and neutralizing natural seaweed. As the calcium sulfate and / or lead silicate used in the present invention, known ones used for conventional impression materials are used without any limitation. Specific examples of particularly preferred examples include calcium sulfate dihydrate, calcium sulfate hemihydrate, calcium sulfate anhydrous, and the like. Further, lead silicate can be used in combination with calcium sulfate or alone. The amount of calcium sulfate and / or lead silicate is 5 to 500 parts by weight per 100 parts by weight of alginate.
It must be in parts by weight, preferably 50 to 20 parts by weight.
0 parts by weight. When the amount of calcium sulfate and / or lead silicate is less than 5 parts by weight, the cross-linking of the alginate is insufficient to cause gelation, and when it exceeds 500 parts by weight, a cured product having an appropriate elasticity is obtained. Absent. In the present invention,
The greatest feature is that zinc oxide having an average particle size of 0.2 to 2 μm is used. If zinc oxide having an average particle size of less than 0.2 μm is used, dust is likely to be generated, which is not preferable. Conversely, if the average particle size is more than 2 μm, the effect of hardening the surface of the gypsum model is not preferable. The average particle size of zinc oxide is preferably in the range of 0.5 to 0.8 μm. As the zinc oxide used in the present invention, known ones can be used without any limitation as long as the average particle diameter is in the range of 0.2 to 2 μm. The amount of zinc oxide is 1 to 20 parts by weight based on 100 parts by weight of alginate. If the amount of zinc oxide is less than 1 part by weight, the effect of hardening the surface of the gypsum model is poor, and
Exceeding the weight part is not preferred because the generation of dust increases. In the present invention, a humectant may be further added to the above-mentioned impression material in order to facilitate the kneading of the impression material and water and suppress generation of dust. The wetting agent need only be mixed into the impression material. The wetting agent is 0.0% in the total amount.
It is preferably in the range of 5 to 1% by weight, and more preferably in the range of 0.1 to 0.7% by weight. With such an amount of the wetting agent, problems such as an increase in permanent set of the cured product, a decrease in impression accuracy, and a delay in gelation time after long-term storage do not occur. In the present invention, it is considered that the use of the wetting agent can be reduced because zinc oxide having a specific average particle diameter is used. Known humectants in the present invention can be used without any limitation. Specific examples include nonionic polymer surfactants such as ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, and polyoxyethylene alkylene ether. The alginate impression material of the present invention includes, as components other than the above, phosphates such as sodium pyrophosphate, trisodium phosphate or potassium salts thereof, oxalic acid or a salt thereof, and fluorosilicate for adjusting the curing time. Sodium or its potassium salt, clay minerals represented by diatomaceous earth, talc, silica, aluminum hydroxide and the like, and oxides or hydroxides of metals or metalloids may be added as extenders. The most preferred embodiment in the present invention is 100 parts by weight of potassium alginate, 50 to 200 parts by weight of calcium sulfate,
0.1 to 1% by weight of humectant in 10 parts by weight
The wetting agent is a polyoxyethylene alkylene ether, and the average particle size of zinc oxide is 0.5 to
The impression material is 0.8 μm.

The impression material of the present invention has low permanent set and reduced dust generation. Furthermore, the generation of dust can be further reduced by adding a wetting agent. If the impression material of the present invention is used, the working environment is good because the generation of dust is small, and there is a moderately high elastic strain,
Since the permanent set is small, there is an advantage that the impression accuracy is high and the hardness of the surface of the gypsum model is high by adding zinc oxide.

EXAMPLES In order to explain the present invention more specifically, the following will be described.
The present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Examples 1 to 5 Powdery components were mixed with the compositions shown in Table 1 to prepare a powdery impression material, and 250 parts by weight of water was added to 100 parts by weight of the powder, and kneaded with a rubber ball for 30 seconds. And knead it into a paste, and determine the gel time, elastic strain, and permanent strain according to JIS.
It was measured according to T-6505. In addition, gypsum hardness was measured in terms of Empitz hardness. The gypsum used was "Stone 1" (trade name) manufactured by Tokuyama Corporation. In addition, diameter 4
10 g of an impression material was placed in a cylindrical glass container of 0 mm × 100 mm height, shaken vigorously for 5 seconds, and the time until the dust was settled was measured. The result is shown in Table 1 as the degree of dust generation. As shown in Table 1, the impression material of the present invention has a high elastic strain, a low permanent set, and generates little dust.

[Table 1] Comparative Example 1 An impression material was prepared in the same manner as in Example 1, except that zinc oxide having an average particle diameter of 0.1 μm was used. The results are shown in Table 1. As a result of measuring the degree of elastic strain, permanent strain, and generation of dust, generation of dust was large and was not a preferable impression material.

Claims (2)

[Claims] 1. Alginate 100 parts by weight, calcium sulfate and / or lead silicate 5 to 500 parts by weight, zinc oxide 1-2 parts
An impression material containing 0 parts by weight as a main component, wherein the zinc oxide has an average particle size of 0.2 to 2 μm. 2. The method according to claim 1, wherein the humectant is contained in an amount of 0.0
An impression material characterized by being contained in the range of 5 to 1% by weight.