Rheological evaluation method of polyethylene for medical instruments

A medical device and evaluation method technology, applied in the field of medicine and medical treatment, can solve the problems of unrepresentable characteristics, high operation requirements, long test cycle, etc., and achieve the effect of low sample uniformity requirements, fast method and low cost

Inactive Publication Date: 2016-01-20
华北石油管理局总医院
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When measuring molecular weight by high-temperature gel permeation chromatography, 1,2,4-trichlorobenzene is used as a solvent for polyethylene samples for medical devices, and 2,6-di-tert-butyl-4-methylphenol is used as an antioxidant Among them, 1,2,4-trichlorobenzene is a highly toxic chemical, which is very toxic to the respiratory tract, skin and mucous membrane tissue of the test operator, and the waste liquid after use has a great impact on the environment; the standard method The operation steps in the method are complicated, and it is often necessary to configure polystyrene solutions of different concentrations to generate a standard calibration curve, which requires high operation requirements; in addition, it takes at least 3-6 hours to dissolve the sample with a solvent in this method, especially for high molecular weight medical devices With polyethylene samples, it often happens that the test data cannot be completely dissolved, which makes the test data untrue, and makes the whole test cycle relatively long; in addition, due to the small amount of polyethylene samples used in medical devices in this test, about 20mg, collected in Part of the sample puts forward higher requirements on the uniformity of the sample itself, otherwise the measured value cannot represent the characteristics of the entire sample

Method used

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  • Rheological evaluation method of polyethylene for medical instruments

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Place polyethylene pellets for medical devices on a hot press with a mold, melt at 200°C for 8.5 minutes, then apply a pressure of 3.5Mpa and continue hot pressing for 4 minutes, and press to obtain a uniform test sample for use; place the sample under strain The controlled rheometer has a diameter of 25mm on a cone-plate fixture with a cone angle of 5°. The torque accuracy of the rheometer is 0.1nNm. The temperature is set at 200°C, a strain of 3% is applied, and the detection frequency range is set at 0.01-100rad / s, take 3 data points for each order of magnitude in logarithmic mode, set the integration time to 2 cycles, measure the characteristic viscosity value when the angular frequency is 0.01rad / s, and measure the modulus when the phase angle is 63° The measured values ​​are listed in Table 1.

Embodiment 2

[0024] Use a mold to place polyethylene pellets for medical devices on a hot press, melt at 260°C for 9.5 minutes, then apply a pressure of 2.5Mpa and continue hot pressing for 2 minutes, and press to obtain a uniform test sample for use; put the sample under strain The controlled rheometer has a diameter of 25mm on a cone-plate fixture with a cone angle of 5°. The torque accuracy of the rheometer is 0.1nNm, the set temperature is 210°C, the strain is 0.5%, and the detection frequency range is 0.001-600rad / s, take 3 data points for each order of magnitude in logarithmic mode, set the integration time to 2 cycles, measure the characteristic viscosity value when the angular frequency is 0.01rad / s, and measure the modulus when the phase angle is 63° The measured values ​​are listed in Table 1.

Embodiment 3

[0026] Use a mold to place polyethylene pellets for medical devices on a hot press, melt them at 210°C for 8 minutes, then apply a pressure of 2Mpa and continue hot pressing for 3 minutes, and press to obtain a uniform test sample for use; place the sample under strain control On the cone-plate fixture with a diameter of 25mm and a cone angle of 5°, the torque accuracy of the rheometer is 0.1nNm, the set temperature is 205°C, 2% strain is applied, and the detection frequency range is set to 0.01-600rad / s , take 5 data points for each order of magnitude in logarithmic mode, set the integration time to 2 cycles, measure the characteristic viscosity value when the angular frequency is 0.01rad / s, and measure the modulus value when the phase angle is 63° , and list the measured values ​​in Table 1.

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Abstract

The invention relates to a rheological evaluation method of polyethylene for medical instruments. The method comprises the steps that a sample of the polyethylene for the medical instruments is placed on a hot press through a mold and pressed into a standby test sample wafer after the sample is completely melted under control of a certain temperature, pressure and time; the sample wafer is placed on a stain control type rheometer fixture, a rheological characteristic value is tested by setting the specific test parameters such as the temperature, the applied strain, the rotating frequency, the point getting mode and the integration time of the rheometer and related to the important properties such as molecular weight and molecular weight distribution of the polyethylene for the medical instruments, and accordingly, the quality of the polyethylene for the medical instruments is quickly evaluated. The evaluation method is fast, easy and convenient to operate, efficient, low in cost and high in precision, the uniform requirement for the sample is low, no environmental pollution is generated, and the application value is achieved in the industrial production detection process.

Description

technical field [0001] The invention relates to a detection method in the field of medicine and medical treatment, in particular to a rheological method for rapidly evaluating polyethylene used in medical devices by using rheological linear viscoelastic characteristics. Background technique [0002] With its excellent performance, good biocompatibility and plasticity, plastics well meet the stringent requirements of the medical field and are widely used in medical products. From simple to complex, low-end to high-end, medical plastic products include disposable injection infusion sets, medical catheters, durable medical products mainly including medical trays and plastic containers, medical outer packaging mainly including blister packaging and plastic bottles, Artificial organs, large, medium and small medical diagnostic instruments, etc. [0003] Medical equipment is one of the largest uses of medical plastics, and it is a fast-growing bulk medical plastic product. There...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N11/00G01N11/14
Inventor 刘保萍王兴宏李丽华唐健滨时耐先赵海英任瑞锋张海涛邵辉马蒲阳刘永红
Owner 华北石油管理局总医院
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