Low-temperature curing powder coating and preparation method thereof

Abstract

The invention discloses a low-temperature curing powder coating and a preparation method thereof. The preparation method comprises the following steps: weighing raw materials by weight parts accordingto a formula, firstly putting 1 / 2 of two-step process epoxy resin in a stirring tank, then putting all other raw materials into the stirring tank, and finally putting the rest 1 / 2 two-step process epoxy resin into the stirring tank; after the feeding is finished, slowly stirring for 3 minutes, and then quickly stirring for 60 seconds; putting the obtained mixture into a feeding hopper of an extruder, melting, extruding, and tabletting and crushing the extruded coating to obtain a sheet; putting the sheet into a grinding machine, grinding, and adjusting the rotating speeds of a main grinder and an auxiliary grinder to enable the particle size D50 to be 32-42 [mu]m; and sieving with a 200-mesh rotary sieve to finally obtain the finished product low-temperature curing powder coating. Spraying production of a part of workpieces which are not resistant to high temperature is satisfied, the coating is also suitable for spraying scenes including automobile oil tanks meeting the national VI standard, and during production implementation, high-end equipment does not need to be replaced or purchased, production can be completed by adopting conventional equipment, so the production cost is low.

Description

technical field [0001] The invention relates to the technical field of powder coatings, in particular to a low-temperature curing powder coating and a preparation method thereof. Background technique [0002] In recent years, due to the advantages of resource saving, energy saving, pollution-free, high efficiency and easy realization of automatic production, powder coating has achieved rapid development in the entire coating technology, and its output has increased rapidly, becoming the development direction of the coating industry. one. [0003] At present, the curing conditions of powder coatings commonly used in the market are at a temperature of 180-210°C and a time of 10-15 minutes. Due to the high curing temperature of this powder coating, it cannot be directly applied to the spraying of some non-temperature-resistant workpieces, such as fuel tanks with plastic accessories. In addition, this kind of powder coating wastes a lot of energy, which does not conform to the...

AI Technical Summary

Problems solved by technology

Due to the high curing temperature of this powder coating, it cannot be directly applied to the spraying of some parts that are not resistant to temperature, such as fuel tanks with plastic accessories.

In addition, this kind of powder coating wastes a lot of energy, which does not meet the national energy conservation and emission reduction policies

[0004] In addition, there are also some low-temperature curing coatings on the market, which have technical advantages such as low curing temperature and short curing time. However, too low curing temperature and too short curing time also put forward higher requirements and challenges for extrusion equipment. At present, the extrusion equipment commonly used in the market is difficult to meet their requirements. Therefore, to achieve their technical goals, it is necessary to systematically replace the equipment in the workshop and purchase high-end equipment with high prices. However, this will inevitably greatly increase the production cost. Unbearable for small paint manufacturers

[0005] In addition, although the existing low-temperature curing powder coatings have made great progress in curing temperature and curing time, it is difficult to meet higher requirements in other indicators, such as the flatness of the paint film after spraying, impact strength, Elasticity, hardness, salt spray resistance, water resistance, alkali resistance, acid resistance, etc.

[0006] While reducing the curing temperature and curing time, the existing low-temperature curing powder coatings also sacrifice the requirements of some other indicators, making it difficult to adapt to more occasions in practical applications

For example, it cannot meet the requirements of the National VI standard automobile fuel tank to first install the internal plastic parts of the fuel tank and then spray the powder coating

In addition, there are some dual-curing systems of ultraviolet rays and infrared rays. For spraying manufacturers, it is necessary to replace the curing equipment, which is a large expense. In addition, the places where ultraviolet rays cannot be irradiated are not completely cured, which will cause The physical and chemical properties of the coating film are reduced or lost. Therefore, this system can only be used on wood and other substrates, and cannot be used for the spraying of automobile fuel tanks that meet the National VI standard.

Images