JP2837857B2 - Manufacturing method of coating material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a coating material, and more particularly to a coating material using a polyphenylene sulfide resin (hereinafter, referred to as a PPS resin) for fluidized immersion. It is.

[Conventional technology and problems] As is well known, PPS resin has excellent heat resistance and mechanical properties,
In addition, attempts have been made to use PPS resins for fluid immersion because safety and non-toxicity are guaranteed. By the way, when a PPS resin is used for fluid immersion, it is required that the floating state of the PPS resin in the fluidized tank be good, that the particle diameter be uniform, and that the PPS resin be in a smooth state without water. . Conventionally, a sieve or a pulverizer has been used to adjust such properties, for example, the particle size of the PPS resin powder. Examples of the sieve include 42.80.100 mesh or more, 42.80.100 mesh or less, 42 to 80 mesh, 80 to 100 mesh, 42 to 270 mesh, and the like. However, when a sieve is used, the particle size of the particles can be made uniform, but the floating state in a fluidized state is poor. On the other hand, when the test was carried out using a pulverizer at the smallest particle size of about 10 μm, the particles became entangled to form secondary particles, and no floating of the resin particles was observed. From these facts, it was found that it was impossible to make a powder coating with a single PPS resin.

Then, an attempt was made to add a filler to the PPS resin particles. As a result, the floating state of the resin particles was improved, and in particular, by adding silica, effects such as smoothing of the coating film after coating and firing and reduction of dripping on the resin during firing were exhibited. However, in this state, it cannot be used for fluid immersion. That is, when used for coating for fluid immersion, the separation of the PPS resin particles and the filler occurs inside the fluidized bed, and the filling effect on the PPS resin particles is not seen at all.
It becomes a coating film of PS resin particles alone, and craters are generated on the coating surface.

The present invention has been made in view of the above circumstances, and after mixing a filler with a PPS resin, crosslinking and pelletizing, and further crushing these pellets while cooling them, thereby imparting gloss and smoothness to the coating film surface. It is an object of the present invention to provide a method for producing a coating material having the same.

[Means for Solving the Problems] The present invention comprises a step of mixing a polyphenylene sulfide resin (PPS resin) and a filler with a mixer, and then subjecting the mixture to a twin-screw extruder to perform cross-linking to form pellets; Pulverizing these pellets into fine powder having a particle size of 50 to 100 μm while cooling the pellets.

As the filler according to the present invention, for example, glass beads,
Examples include titanium oxide, carbon black, silica, graphite, silicon carbide, and silane coupling agents.

In the present invention, the pellets are pulverized into fine powder having a particle size of 50 to 100 μm because when the particle size is less than 50 μm, the air passes through the mass of the fluid when flowing and immersed, and the fluidity deteriorates. On the contrary, if the particle size exceeds 100 μm, sufficient smoothness of the coating film cannot be obtained.

[Action] In the present invention, after appropriately mixing the filler and the PPS resin powder, the resulting mixture is pelletized by promoting cross-linking, and the obtained pellets are further pulverized into fine powder having a particle size of 50 to 100 μm. Therefore, if these fine powders are used as a material for a coating film for fluid immersion, a resin for a coating film for fluid immersion having excellent gloss and smoothness can be obtained.

Example An example of the present invention will be described below.

First, a fine silica powder having an average primary particle diameter of 7 μm (trade name Aerosil, manufactured by Nippon Aerogel Co., Ltd.) and a PPS resin powder are mixed using a mixer.

Next, the mixture is twin-screw extruded (operating temperature: 300 to 400
C) to promote crosslinking and pelletize.

Subsequently, the obtained pellets are, for example, refrigerated in a nitrogen atmosphere, for example, with a primary particle average particle size of 50 to 100 μm.
To a fine powder. As a result, a fluid immersion coating material was obtained.

According to the above example, after the fine silica powder and the PPS resin powder are mixed using a mixer, the mixture is pelletized by promoting cross-linking in a twin-screw extruder, and the obtained pellets are further mixed, for example, in a nitrogen atmosphere. In order to pulverize into fine powder with primary particle average particle size of 50 to 100 μm by a freeze-pulverizer, these fine powders were applied to the surface of metal etc. as a coating material for fluid immersion. Poor sex,
Alternatively, a coating film having excellent gloss and smoothness was obtained without roughening the surface.

In the above-described embodiment, the case where the pellets obtained from the filler fine powder and the PPS particles have a primary particle average particle size of 50 to 100 μm is described.
It should just be in the following range.

Further, in the above embodiment, the case where the fine powder of silicic acid is used as the filler has been described. However, the present invention is not limited to this, and other fillers such as glass beads and carbon black may be used.

[Effects of the Invention] As described in detail above, according to the present invention, after mixing the filler with the PPS resin, crosslinking and pelletizing, and further crushing these pellets while cooling, the material thus obtained is When applied to a surface of a metal or the like by fluid immersion, it is possible to provide a method for producing a coating material having excellent gloss and smoothness on the surface of the coating film.

Claims (1)

(57) [Claims] 1. A step of mixing a polyphenylene sulfide resin and a filler with a mixer, cross-linking the mixture with a twin-screw extruder to form pellets, and cooling the pellets to a particle size of 50 to 100 μm. Pulverizing to a fine powder of the above.