JPS6011060B2 - Polyphenylene sulfide composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a poly-IJ phenylene sulfide composition that has extremely little thermochromic property and excellent thermal stability.

Since polyphenylene sulfide has excellent heat resistance and chemical resistance, it is sometimes used as a coating material for rust prevention and corrosion prevention on various molded products and metal surfaces.

However, although the resin is white to grayish white before melting, when it is melted at a high temperature of 320°C or higher, it changes color due to heat and becomes a black or blackish brown molded product or coating. There was a drawback in that it was difficult to add pigments to achieve a desired color, as has been done in the past.
Conventionally, in order to improve such drawbacks, a method of preventing thermal discoloration of polyarylene sulfide by treating it with monothiol or polythiol has been proposed, for example, in U.S. Pat. No. 34 Female I No. 2' A method has been proposed to prevent thermal discoloration of polyarylene sulfide by treating it with a hydroxy-substituted amine, but both methods require complicated and long processing steps, making it uneconomical. Moreover, it has disadvantages such as insufficient thermal discoloration prevention effect unless the processing agent is completely removed. Furthermore, Japanese Patent Publication No. 50-18107 proposes a method of preventing thermal discoloration of polyarylene sulfide by adding organic phosphinic acid or organic phosphite, but since it is an organic additive, it cannot be heated and melted at high temperatures. During this process, the additive decomposes and the effect of preventing thermal discoloration is lost, which has a negative impact on the product. In view of the above points, the present invention provides 320
This was created with the aim of providing a polyphenylene sulfide composition that exhibits almost no thermal discoloration even when melted at a high temperature of 0.00 or higher, has excellent thermal stability, and has mechanical properties no inferior to conventional compositions. The gist thereof lies in a polyphenylene sulfide composition in which a sulfide of an element belonging to Group B of the periodic table is added to polyphenylene sulfide.

In the present invention, polyphenylene sulfide refers to a resin in which the primary mirror is made up of repeating units, and may be partially oxidized or have a branched or crosslinked structure.

Examples of sulfides of elements belonging to Group 0 of the periodic table used in the present invention include calcium sulfide, zinc sulfide, strontium sulfide, cadmium sulfide, barium sulfide, etc. Among them, calcium sulfide and zinc sulfide are preferably used. It will be done.

Furthermore, regarding the amount of sulfide of the element belonging to Group U of the periodic table, if it is too small, it is difficult to expect the effects of the present invention, and if it is too large, the strength and physical properties of the molded product or coating film may deteriorate. Therefore, in the present invention, it is preferable to use 5 to 10 parts by weight, particularly preferably 10 to 5 parts by weight, per 100 parts by weight of polyphenylene sulfide.

Next, in order to produce the polyphenylene sulfide composition of the present invention, the polyphenylene sulfide and a sulfide of an element belonging to Group B of the periodic table may be added and mixed. For example, a Banbury mixer, a Brabender mixer, etc. can be used.

The polyphenylene sulfide composition obtained in this way can be prepared by mixing polyphenylene sulfide alone or with commonly used white fillers such as aluminum oxide, titanium oxide, zinc oxide, tin oxide, calcium carbonate, and barium carbonate. 3 compared to polyphenylene sulfide compositions.
Even if it is melted at a high temperature of 20° C. or higher, it hardly turns black and discolors due to heat, making it possible to obtain molded products or coatings that are close to white, which has not been previously possible.

The reason why there is almost no thermal discoloration even when melted in the present invention as described above is not clear in detail, but the sulfide of the element belonging to Group 0 of the periodic table in the present invention prevents the formation of coloring substances. It is assumed that this is because

In the present invention, dyes, pigments, fillers, plasticizers, etc. may be added to the polyphenylene sulfide composition as appropriate.

Since the polyphenylene sulfide composition of the present invention is made by adding a sulfide of an element belonging to Group 0 of the periodic table to polyphenylene sulfide as described above, the composition can be used as a molded article or coating material. When used, it is possible to obtain molded products or paint films with almost white color after melting, with almost no discoloration due to heat compared to conventional compositions, and it is easy to obtain molded products or paint films with a desired color by adding any pigment. can be obtained.

The polyphenylene sulfide composition of the present invention has excellent heat resistance, chemical resistance, and thermal stability when melted, so it can be used to manufacture various products, mainly electronic equipment materials, by injection molding and extrusion molding. Suitable for forming internal coatings on pipes, pipe joints, elbows, etc. that are used under high-temperature hot water conditions, and surface coatings on rope blades, pump rollers, etc. that require rust and corrosion resistance. suitable for use as Next, the present invention will be explained in detail with reference to examples.

In the following examples, the color difference (ΔE) was measured using a color difference meter (Digital Color Meter TC360U, manufactured by Tokyo Denshoku ■). S. The values of L, a, and b of the reflected light of the sample and the standard white plate (magnesium oxide) in the UCS color system devised by Hun were determined and calculated using the '1' formula.
△E Nizo (L-L2) 20 (a, 1 too) 20 (b, 10) 2
0) Here, L is the lightness, a and b are the scales representing the saturation and hue (more precisely, the chroma is the saturation and b/a is the hue), and the subscript 1 is the scale for each sample, the subscript 2 represents a standard white plate, and indicates that the smaller the value of ΔE, the closer to white the plate becomes.

Example 1 2 parts by weight of polyphenylene sulfide (Ryton V-1, manufactured by Phillips Vetroleum) and 2 parts by weight of zinc sulfide
A pale yellow sheet with a thickness of 1 skin and hardly discolored by heat was obtained by press-molding at 340 oo.

Table 1 shows the color difference measurement results of the sheet thus obtained. Furthermore, when the above sheet was heated in an oven at an ambient temperature of 340°C for 120 minutes, as shown in Table 1, the change in color difference (△E) before and after heating was 3.8, indicating excellent thermal stability. . For comparison, the same polyphenylene sulfide as in Example 1 was press-molded at 340°C, but only a heat-discolored black sheet with a thickness of one rib was obtained.

The color difference measurement results of the sheet thus obtained are shown in Table 1 as Comparative Example 1. For comparison, 20 parts by weight of aluminum oxide was added to and mixed with 10 parts by weight of the same polyphenylene sulfide as in Example 1, and the mixture was press-formed at 340°C, but only a heat-discolored black sheet with a thickness of 1 layer was obtained. I couldn't get it. The color difference measurement results of the sheet thus obtained are shown in Table 1 as Comparative Example 2. Example 2 5 parts by weight of zinc sulfide were added to 10 parts by weight of the same polyphenylene sulfide as in Example 1, and press molded at 340 oo to obtain a pale yellow sheet with a thickness of 1 willow and almost no heat discoloration. Obtained.

Table 1 shows the color difference measurement results of the sheet thus obtained. Furthermore, when the above sheet was heated in an oven at an ambient temperature of 340 pm for 120 minutes, the change in color difference (△E) before and after heating was 3.9, which was 4. It was. Table 1

Claims (1)

[Scope of Claims] 1. A polyphenylene sulfide composition in which a sulfide of an element belonging to Group II of the periodic table is added to polyphenylene sulfide. 2. The polyphenylene sulfide composition according to claim 1, wherein the sulfide of the element belonging to Group II of the periodic table is calcium sulfide, zinc sulfide, strontium sulfide, or barium sulfide. 3. The amount of sulfide of an element belonging to Group II of the periodic table is 5 to 1 per 100 parts by weight of polyphenylene sulfide.
00 parts by weight of the polyphenylene sulfide composition according to claim 1 or 2.