SU933091A1 - Composition for moulding models of prosthesis receiving sleeves - Google Patents

Description

I

The invention relates to the field of medicine, in particular to prosthetics and prosthesis, and can be used in the manufacture of technological models-positives of the internal cavities of the receiving sleeves of limb prostheses, as well as in engineering in the manufacture of models, for example for stamping parts.

A known composition for forming models of prosthetic liners, containing semi-aquatic gypsum and water O.

This formulation is the closest solution to the described invention.

The technology of making products from it is simple, the material is not scarce and cheap.

However, the positive models of the internal cavities of the receiving sleeves obtained from this material have high mechanical strength. Removing them from the billet of the prosthetic receiving sleeve is performed by means of metalworking

percussion instruments, embossing plaster positive. This requires considerable time and manual labor, and can also lead to damage to the workpiece.

The aim of the invention is to reduce the mechanical strength of the mold.

This is achieved by the fact that the proposed composition for forming models

10 prosthetic liners, containing semi-aquatic gypsum and water, additionally contain polyvinyl formal in the following ratio of components, wt.%:

15

Semi water gypsum

Penopoli vinylformal2-10

WaterOther Composition was prepared as follows.

20

Claims (2)

They take semi-aquatic gypsum in powder form and polyvinyl formal with a particle size of 0.25-2 mm with a ratio of components, mass. 39 Semi-aqueous gypsum 35 about Penopoli is nilformal2-10 and mixed. The mass obtained, with constant stirring, is shut off with water, and the addition to the semi-aquatic gypsum of crystallization water with the formation of Ca50d.2H2p dihydrate takes place. The reaction proceeds with the release of a significant amount of heat, which helps to remove moisture from the positive. Introduction to the composition of polyvinyl chloride helps loosen the structure of gypsum and reduce its mechanical strength. Curing in the form is carried out at 15-20 ° C for 5-10 minutes. After this, the model is removed, dried in a drying cabinet at 60-80 ° C for 72 hours, and used in the manufacture of a prosthetic liner for extremities. In the process of heat treatment in the proposed material, physical and chemical transformations occur, which leads to loosening of its structure. For example. The following substances are taken as initial components, mass g: Semi-aquatic gypsum (2CaSO ".H 0) in powder state 420 Polyvinyl foam form with a particle size of 2 mm 80 Water 500 For comparison, take the known composition of mass: Semi-Aquatic gypsum (ZCaSOy.) in the powdered state i50 In preparing the first formulation, first mix the semi-aqueous gypsum and polyvinyl formal, and then mix the resulting mass with continuous mixing with water. This mass is filled with a negative form prepared on the cult of a disabled person who is in the prosthetic clinic, i.e. make a positive model. In addition, 5 specimens with dimensions of 20-202020 mm are fabricated from this mass to determine the breaking stress under compression. Similarly, model positives and specimens are made to determine the compressive strength of the second composition (control). The resulting positive models and samples for the test of compressive strength, after curing for 15 minutes, are placed in a heating cabinet (type SNOL 3.5.3.5.3.5 / 3M) and incubated for 72 hours. Samples made of two compositions were tested for compressive strength on a laboratory screw press with registration of destructive stress using a DOSM-3-0 dynamometer, 2. Compressive strength, kgf / cm: The first composition5 The second composition (control) kQ The resulting positive models are also freed from the negative form and, according to them, made of the prostheses of the lower leg are made of reinforced polyethylene, which follow the shape of the model. The blanks are placed in a heating chamber and kept there for two hours at. After soaking in the heating chamber, the blanks of the receiving sleeves of the leg are freed from positive models, while the destruction of the control model took 15 minutes for the model made of the first composition to destroy with the help of metalworking percussion tools. Depending on the amount of additive, the mechanical strength of the form decreases by 4-5 times in comparison with the known. As an additive, you can use the waste polyvinyl formal used in prosthetics for the manufacture of water-absorbing support elements. Thus, the proposed material has increased brittleness and reduced mechanical strength, which allows to increase labor productivity when removing models from blanks of the receiving cavities of prosthetic liners or other parts, to reduce the likelihood of mechanical damage to manufactured parts. This makes it possible to improve their quality, which is especially important in the manufacture of prosthetic limb liners. The proposed composition for forming models of prosthetic replacement sleeves meets the requirements for materials for the manufacture of the latter in prosthetic limbs. DETAILED DESCRIPTION OF THE INVENTION A composition for forming models of prosthetic inserts, containing semi-aquatic gypsum and water, characterized in that, in order to reduce the mechanical strength of the mold, it contains peyographer 5933091 6 mal in the following ratio of com- Sources of information ponents, wt.%: taken into account in the examination Semi water gypsum 35 O Penopolivinil-. 1. Kotov A.P. Fundamentals of prosthetic formal 2-10 5 Kiev-Kharkov, Medicine,, Water Else with, 88 (prototype).