A kind of flexible composite material with sandwich structure and its preparation method and application

A composite material and sandwich technology, applied in the field of forensic science, can solve problems such as unsatisfactory rapid detection and on-site detection, long reaction time, printing ink diffusion, etc., to achieve enhanced fingerprint display effect, wide range of applicable objects, and low cost Effect

Active Publication Date: 2019-11-15
ZHEJIANG POLICE COLLEGE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has an obvious effect in displaying fingerprints, but at the same time, the process of impregnating the object with chemical reagents will cause a certain degree of damage or influence on the object, such as coloring the background of the object surface, causing the printing ink on the paper object to diffuse, destroying the handwriting, etc., thereby Negative effect on the provision of case clues
On the other hand, the traditional method of using chemical reagents such as silver nitrate and ninhydrin to reveal fingerprints needs to be fumigated in a fumigation cabinet, and the reaction takes a long time, which cannot meet the requirements of rapid detection and on-site detection

Method used

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  • A kind of flexible composite material with sandwich structure and its preparation method and application
  • A kind of flexible composite material with sandwich structure and its preparation method and application
  • A kind of flexible composite material with sandwich structure and its preparation method and application

Examples

Experimental program
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Effect test

Embodiment 1

[0023] 1) Mix ninhydrin and ethanol uniformly in a mass ratio of 0.1:10 to obtain a developer, and mix polyvinyl alcohol and water in a mass ratio of 0.1:5 to obtain an emulsion. The developer and emulsion are mixed in a mass ratio of 9 : 1 ratio mixed evenly to obtain the reaction solution;

[0024] 2) Mix iron powder, water, activated carbon, sodium chloride, starch-grafted acrylic acid polymer, and silicon carbide-filled silicone rubber according to the mass ratio of 58:24:5:4:1:9 to obtain a self-heating slurry;

[0025] 3) The reaction solution was mixed at 20 μl / cm 2 The concentration is evenly added dropwise to one side of the polyethylene terephthalate substrate, dried naturally for 20 minutes to form a reaction layer, and then the self-heating slurry is mixed at 40 μg / cm 2 Evenly apply the concentration on the other side of the polyethylene terephthalate substrate, and let it dry naturally for 20 minutes to form a self-heating layer, that is, to obtain a flexible com...

Embodiment 2

[0028] 1) Indandione and ethanol are mixed uniformly in a mass ratio of 0.12:10 to obtain a developer, polyethylene glycol 8000 and water are uniformly mixed in a mass ratio of 0.2:5 to obtain an emulsion, and the developer and emulsion are obtained by The ratio of mass ratio 10:1 is mixed evenly to obtain the reaction solution;

[0029] 2) Mix iron powder, water, activated carbon, sodium chloride, starch-grafted acrylamide polymer, and alumina-filled silicone rubber according to the mass ratio of 56:25:4:5:2:8 to obtain a self-heating slurry ;

[0030] 3) The reaction solution was mixed according to 18 μl / cm 2 The concentration is evenly added dropwise to one side of the polyethylene terephthalate substrate, dried naturally for 30 minutes to form a reaction layer, and then the self-heating slurry is mixed at 50 μg / cm 2 Evenly apply the concentration on the other side of the polyethylene terephthalate substrate, and let it dry naturally for 30 minutes to form a self-heating ...

Embodiment 3

[0033] 1) Mix 1,2-indandione and ethanol uniformly at a mass ratio of 0.08:10 to obtain a developing solution, mix polyethylene glycol 6000 and water at a mass ratio of 0.1:5 to obtain an emulsion, and develop Liquid and emulsified liquid are mixed evenly in the ratio of mass ratio 8:1 to obtain reaction liquid;

[0034] 2) Mix iron powder, water, activated carbon, sodium chloride, polyacrylic superabsorbent polymer, and zinc oxide filled silicone rubber according to the mass ratio of 57:24:5:3:1:10 to obtain self-heating slurry ;

[0035] 3) The reaction solution was mixed at 23 μl / cm 2 The concentration of the polyimide substrate is evenly added dropwise to one side of the polyimide substrate, and it is naturally dried for 40 minutes to form a reaction layer, and then the self-heating slurry is mixed at 70 μg / cm 2 The concentration of the polyimide substrate is evenly applied to the other side of the polyimide substrate, and it is naturally dried for 40 minutes to form a s...

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Abstract

The invention belongs to the field of court science, and in particular relates to a flexible composite material with a sandwich structure, and application thereof. The preparation method of the flexible composite material with the sandwich structure comprises the following steps: dissolving a developing agent into ethanol, dissolving an emulsifying agent into water, and mixing the two solutions to obtain reaction liquid; mixing iron powder, water, activated carbon, sodium chloride, a high water-absorbing polymer and heat-conducting silica gel uniformly to obtain spontaneous heating slurry; and adding the reaction liquid on one side of a flexible substrate uniformly and dropwise, drying, coating the other side of the flexible substrate with the spontaneous heating slurry uniformly, and drying to obtain the flexible composite material with the sandwich structure, wherein the flexible composite material with the sandwich structure consists of a reaction layer, the flexible substrate and a spontaneous heating layer. The flexible composite material is placed on an object with fingerprints left and enables the reaction layer to contact with the fingerprints, so that the latent fingerprints can be shown quickly. The method has the characteristics of simplicity in operation, low cost, portability, high showing speed, no damage to check materials and the like, and high practicability is achieved.

Description

technical field [0001] The invention belongs to the field of forensic science, and in particular relates to a flexible composite material with a sandwich structure and a preparation method and application thereof. Background technique [0002] Fingerprints are protruding lines on the skin of human fingers. As a genetic trait of human beings, fingerprints are different for each person and remain unchanged for life. Due to its uniqueness, lifelong invariance and convenience, fingerprints have become an important means of biometric identification. Fingerprints are also one of the most important evidence at the crime scene. According to the characteristics of fingerprints, the same identification can be made to determine the suspect. When the finger touches the object, the sweat, grease and other components in the finger will remain on the surface of the object, forming fingerprints invisible to the naked eye, that is, latent fingerprints. In most cases, the fingerprint left o...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): A61B5/1172C08J7/04C08L67/02
CPCA61B5/1172C08J7/042C08J2367/02
Inventor 周婧
Owner ZHEJIANG POLICE COLLEGE
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