JPH0567659B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to a fluororesin coloring composition, and more particularly to a fluororesin coloring composition that does not cause corrosion of the molding machine main body and peripheral equipment by fluorine gas when fluororesin is heated and molded. (Prior Art) Conventionally, fluororesins with a high fluorine content, such as polytetrafluoroethylene or their copolymer resins, have excellent physical properties such as heat resistance and chemical resistance.
Because of its chemical properties, it is widely used as a heat-resistant or chemical-resistant material for various devices and members. Fluororesins are widely used, including those that are difficult to melt and are processed into powder molding, and those that can be melted and molded with various molding machines because they have heat-melting properties. Requires very high temperatures. (Problems to be Solved by the Invention) When molding conventional fluororesins as described above, especially when melt molding, high temperatures of 350 to 400°C, which are unthinkable for ordinary thermoplastic resins, are used. Therefore, a part of the fluororesin is thermally decomposed during heating and generates fluorine gas or fluorine-based gas such as hydrogen fluoride. For this purpose, the main body of the molding machine, such as the cylinder, die, vent hole, heater of the extruder, the mold, screw, cylinder, nozzle of the injection molding machine, the mold and peripheral equipment of the heating press machine, such as the exhaust duct, Very expensive corrosion-resistant special alloys are used for hoppers, pelletizers, etc., and even if these alloys are used, their service life is not sufficient, which is an important factor in increasing the processing costs of fluororesin. This is a contributing factor. In addition, due to the deterioration of the above-mentioned equipment, a problem has arisen in which corrosive metal compounds, powder, fragments, etc. are mixed into the fluororesin molded product, resulting in a decline in the color clarity, surface properties, electrical properties, etc. of the molded product. . In addition, when fluororesin is used in combination with lining or coating various metals, glass, etc., residual corrosive gas that exists between the linings during processing or after molding may penetrate over time. There is a problem that metal, glass, etc. that are direct or indirect base materials deteriorate. Furthermore, reinforcing agents such as glass fibers are sometimes mixed into fluororesin to make FRP, but since fluorine-based gas is generated during molding, the deterioration of these reinforcing agents is significantly accelerated and Adding vitreous reinforcing agents and additives to these products has been considered a problem. Therefore, when molding fluororesin, there is a need for a means to prevent corrosion of the molding machine main body and peripheral equipment, and a technique that allows glass reinforcing agents and additives to be incorporated into fluororesin without deterioration. In addition, during the process of manufacturing pigment masterbatches for fluororesin for many years, the present inventor has recognized that the corrosion phenomenon on the screws of the extrusion molding machine varies greatly depending on the type of pigment in the masterbatch. In terms of stabilization and equipment maintenance, it was necessary to solve this problem. The demands of the prior art as described above have been satisfied by the present invention as described below. (Means for Solving the Problems) That is, the present invention provides at least one selected from the group consisting of cobalt oxide blue, silicate-coated yellow lead, silicate-coated molybdate orange, and silicate-coated iron oxide per 100 parts by weight of fluororesin. 0.01 of one type of pigment
This is a fluororesin coloring composition characterized by containing at least parts by weight. Next, to explain the present invention in more detail, the present inventor has conducted extensive research into coloring and molding fluororesin with pigments, and has found that among various pigments, fluorine is added during high-temperature heat molding at the same time as coloring fluororesin. There are pigments that can sufficiently prevent or suppress the decomposition of resins or the generation of fluorine-based gases, and by blending such pigments with fluororesins,
At the same time as coloring the fluororesin, it is possible to prevent or suppress thermal decomposition or generation of fluorine gas during high-temperature heat treatment of the fluororesin, and the various problems of the prior art described above are solved. The fluororesin used in the present invention is a hydrocarbon polymer in which hydrogen atoms are substituted with fluorine atoms, such as vinyl fluoride,
Vinylidene fluoride, dichlorodifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, hexafluoropropylene, (meth)
Homopolymer resins of monomers such as highly fluorinated alcohol esters of acrylic acid, copolymer resins thereof,
Alternatively, copolymer resins with other monomers are particularly preferred in the present invention, such as tetrafluoroethylene-hexafluoropropylene copolymer resins and perfluoroalkoxy-tetrafluoroethylene copolymer resins. Such fluororesins themselves are widely known and can be easily obtained from the market and used in the present invention. Further, in the present invention, a blend polymer obtained by blending the above-mentioned fluororesin with other resins is also effective. The pigments used in the present invention are as described above, but
These pigments must be blended in an amount of at least 0.01 part by weight per 100 parts by weight of fluororesin.
If the amount is less than 1 part by weight, the desired effect of the present invention will not be sufficiently achieved. Also, if the amount is too large, the moldability will be poor and the physical properties of the molded product will deteriorate, so it is not preferable. Add to. The fluororesin coloring composition of the present invention is obtained by blending the above-mentioned fluororesin and pigment, and can be in the form of powder by mixing powders, colored pellets, flakes, etc. by melt-kneading the mixture. It may be of any shape, and its pigment concentration may be equal to the final coloring density of the molded product, or it may be of high concentration such as a color masterbatch or color concentrate. The fluororesin coloring composition of the present invention contains a fluororesin and the above-mentioned pigment as essential components as described above, and can also contain various conventionally known additives and fillers for fluororesins. It is also effective for glass-based reinforcing agents and fillers such as, etc. Furthermore, even when used in combination with pigments that conventionally have insufficient heat resistance and discolor, such discoloration of such pigments can be prevented and even more beautiful coloring processing can be achieved. is possible. (Function/Effect) According to the present invention as described above, the fluororesin coloring composition of the present invention prevents or prevents the generation of fluorine-based gas due to decomposition of the fluororesin even if it is heated and molded at extremely high temperatures. Since the molding machine is sufficiently suppressed, the corrosion of the molding machine body, peripheral equipment, and applied materials are sufficiently prevented, and their service life is greatly extended. Furthermore, conventionally, when vitreous reinforcing agents and fillers such as glass fibers were blended, the vitreous properties deteriorated and sufficient effects could not be obtained. However, in the present invention, since there is no discoloration of the pigments used or used in combination, it is possible to provide colored molded products that are beautiful and have excellent various strengths. Furthermore, when the fluororesin coloring composition of the present invention is used by lining or coating various metals, glasses, etc., the metals, glasses, etc. that are direct or indirect base materials will not deteriorate and will remain stable over time. , it is possible to provide colored molded products with excellent various strengths. Next, the present invention will be explained in more detail with reference to Examples. In the text, parts and percentages are based on weight unless otherwise specified. Example 1 Cobalt oxide blue pigment and 5 parts of silicic acid-coated yellow lead pigment were individually blended into 100 parts of 4-fluorinated ethylene-6-fluorinated propylene copolymer resin (Teflon #100), and some of the materials were SKH. A 65 m/m extruder with extrusion head temperature set at 390 °C, cylinder temperature 350 °C, cylinder temperature 360 °C, cylinder temperature 370 °C, and cylinder temperature 380 °C with a screw incorporating the parts replaced with tool steel. After extruding 300 kg of each screw, the corrosion resistance of the screw surface was examined, and no trace of corrosion was observed on the SKH tool steel parts assembled as parts. Comparative Example 1 5 parts of cadmium sulfide pigment in 100 parts of tetrafluoroethylene-6fluoropropylene copolymer resin (Teflon #100)
A mixture of 10% and 100% pigment-free resin and a single resin without pigments were respectively molded using an extrusion molding machine under exactly the same conditions as in Example 1.
When 300Kg was extruded and the corrosion of the screw surface was investigated, significant corrosion was observed on the SKH tool steel part in all cases. Example 2 0.5 parts of the pigments shown in Table 1 below were individually blended into 100 parts of 4-fluorinated ethylene-6-fluorinated propylene copolymer resin (Teflon #100), and mixed thoroughly to obtain 8 types of fluorine of the present invention. A resin colored composition was obtained. Next, these 10 kinds of mixtures are extruded using a 30 m/m extrusion molding machine set at an extrusion head temperature of 390°C, a cylinder temperature of 380°C, and a cylinder temperature of 385°C to form colored pellets of the fluororesin of the present invention. It was made into a composition. 50mg of each of the above 10 types of colored pellets was sandwiched between two iron plates and heated to about 50μm on a hot plate at 400℃.
It was rolled into a film. After heating the film in that state for 10 minutes, the two iron plates were separated and the corrosion of the surface of the iron plate around the film was examined, and the results shown in Table 1 below were obtained. Example 3 100 parts of perfluoroloalkoxy-tetrafluoroethylene copolymer resin (Teflon 340-J) and 5 parts of the pigments listed in Table 1 below were individually blended to produce eight types of fluororesin coloring compositions of the present invention. I got something. Each of these blends was heated at an extrusion head temperature of 390°C.
Cylinder temperature 380℃, cylinder temperature 385℃
The fluororesin coloring composition of the present invention was extruded using an extrusion molding machine set at 19 m/m to obtain a color masterbatch-shaped fluororesin coloring composition of the present invention. These 10 types of colored pellets are each coated with Teflon.
They were mixed at a ratio of 10 parts per 100 parts of 340-J and extruded using an extruder under the conditions of Example 1 to obtain a colored pellet-like fluororesin colored composition of the present invention. These 10 types of colored pellets were subjected to iron plate corrosion tests in the same manner as in Example 1.
Obtained the results in the table. Comparative Example 2 In place of the pigment in Example 1, the pigments shown in Table 1 below were used in the same proportions, and colored pellets were obtained in the same manner as in Example 1, and these were also subjected to the iron plate corrosion test. However, the results shown in Table 1 below were obtained. Example 4 100 parts of perfluoroalkoxy-tetrafluoroethylene copolymer resin (Teflon 340-J) and the pigments listed in Table 2 below were mixed in three different amounts: 0.01 part, 0.1 part, and 10 parts. Thus, a fluororesin colored composition of the present invention was obtained. Colored pellets were obtained from each of these compositions in the same manner as in Example 2, and the iron plate corrosion test was conducted on these pellets in the same manner, and the results shown in Table 2 below were obtained.

【table】

[Table] The ratios in parentheses in Tables 1 and 2 above are the weight mixing ratios of pigments, and the symbols a to m are as follows. a: titanium oxide c: carbon black d: cobalt oxide blue e: cadmium oxide f: silicic acid coated molybdate orange g: cadmi orange h: cadmi yellow i: silicic acid coated yellow lead k: silicic acid coated iron oxide brown l: oxidation Chrome Green M: Cobalt Violet ○: No surface change in gas contact area. △: Corrosion is observed on the surface of the gas contact part. ×: Severe corrosion is observed on the surface of the gas contact area. As is clear from the above Tables 1 and 2, in the case of the present invention which does not contain pigment (colorless), heating of the fluororesin causes significant corrosion to iron plates. Even when colored with pigments such as orange, cadmium yellow pigments, and chromium oxide green, the same corrosive properties as uncolored resins were observed. On the other hand, in the case of the present invention, a sufficient corrosion prevention effect was observed in all cases, and stable and clear coloring was achieved.

Claims (1)

[Scope of Claims] 1. At least 0.01 part by weight of at least one pigment selected from the group consisting of cobalt oxide blue, silicate-coated yellow lead, silicate-coated molybdate orange, and silicate-coated iron oxide per 100 parts by weight of fluororesin. A fluororesin coloring composition. 2. According to claim 1, the fluororesin is a tetrafluoroethylene-hexafluoropropylene copolymer, a perfluoroalkoxy-4-fluoroethylene copolymer, or a fluororesin mixture containing these resins. fluororesin coloring composition.