METHOD OF ASSESSING THE HOMOGENEITY OF PLASTICS

Abstract

Fluorescent pigment is introduced into the plastic composition, preferably a thermoplastic, especially polyethylene or polypropylene, in the granules formation stage, in addition to possible standard components of the composite, mixed, granules are formed, and then the granules are formed into a finished building material component, and then, with the help of a known fluorimeter, the fluorescence intensity of individual parts of the surface of a plastic element is measured and the homogeneity of the material is inferred on the basis of the differences in the results of the fluorescence intensity measurements.

Claims

1. A method of assessing the homogeneity of plastics in a finished construction material, especially in a ventilation duct, characterized in that, in addition to possible standard components of the composite, a fluorescent pigment is introduced into the plastic composition, mixed, possibly granulated, and then formed into a finished element of construction material, then, using a known fluorimeter, the fluorescence intensity of individual parts of the surface of the plastic element is measured and the homogeneity of the material is inferred on the basis of the differences in the results of the fluorescence intensity measurements.

2. The method according to claim 1, characterized in that an optical brightener is used as the fluorescent dye, the fluorescence of which is ignited by ultraviolet radiation.

3. The method according to claim 2, characterized in that 2,5-thiophenediylbis (5-tert-butyl-1,3-benzoxazoles) is used as the fluorescent dye.

4. The method according to claim 2, characterized in that 4,4'-Bis (2-benzoxazolyl) stilbene is used as the fluorescent dye.

5. The method according to claim 2, characterized in that 2-[4-[2-[4-(benzoxazol-2-yl)phenyl]vinyl]phenyl]-5-methylbenzoxazole is used as the fluorescent dye.

6. The method according to claim 2, characterized in that 1,4-Bis(2-benzoxazolyl)naphthalene is used as the fluorescent dye.

7. The method according to claim 2, characterized in that 4,4'-bis(2-methoxystyryl)-1,1'-biphenyl is used as the fluorescent dye.

8. The method according to claim 1, characterized in that 0.001% to 0.05% of a fluorescent pigment is added to the granulate.

9. The method according to claim 1, characterized in that thermoplastics are used as the plastic.

10. The method according to claim 9, characterized in that thermoplastic is polyethylene.

11. The method according to claim 9, characterized in that thermoplastic is polypropylene.

Description

THE SUBJECT MATTER OF THE INVENTION IS SHOWN IN THE EXAMPLES

Example I

[0014] In compounding technology, 5 g of solid 2,5-tiofenediylbis(5-tert-butyl-1,3-benzoxksazol) optical brightener are added to 5 kg of polyethylene and the extrusion granulated substance is formed. The granulated substance with the fluorescent dye is mixed with 20 kg of pure polyethylene granules and a ventilation channel is formed by extrusion. The surface of the finished ventilation duct is scanned in many places and the intensity of fluorescence is measured. The measurement results are compared with each other and on this basis it is concluded that the mass of the material is homogeneous.

Example II

[0015] While mixing, to 100 kg of polypropylene, 1 g of solid 4,4'-bis (2-benzoxazolyl) stilbene optical brightener is added and passed to the pipe extrusion process. The plastic mixed with the dye is plasticized, compressed and extruded through the head of the pipe extruder, after which the pipe is calibrated and cooled in a calibrating cooling bath and dried. The polypropylene granules are plasticized compressed and extruded through the head of the extruders of the protective layer and a two-layer casing pipe is formed on the pipe with the dye, and then, in the crimping device — corugator, the corrugated surface of the pipe is formed under vacuum pressure, which is then calibrated under vacuum, stabilized by cooling with water in a spray bath and then dried. The inner surface of the finished pipe is scanned at multiple places and the fluorescence intensity is measured. The measurement results are compared with each other and on this basis it is concluded that the mass of the material is homogeneous.

Example III

[0016] While mixing, to 200 kg of polypropylene, 100 g of solid optical brightener 2-[4-[2-[4(benzoxazol-2-yl) phenyl] vinyl] phenyl] -5-methylbenzoxazole is added to the process of extrusion of the air duct. The plastic mixed with the dye is plasticized, compressed and extruded through the extruder head, after which the channel is calibrated and cooled in a calibrating cooling bath and dried. The polypropylene granulate is plasticized and extruded through the extruder head of the protective layer and a casing pipe is formed on the pipe with the dye, after which the channel is vacuum calibrated, stabilized by cooling with water in a spray bath and dried. The inner surface of the finished pipe is scanned at multiple places and the fluorescence intensity is measured. The measurement results are compared with each other and on this basis it is concluded that the mass of the material is homogeneous.