JPH05271540A - Polyarylene sulfide resin composition resistant to discoloration with light - Google Patents

Abstract

PURPOSE:To obtain the subject composition having high whiteness, stable color and remarkably improved resistance to discoloration with light while keeping the excellent characteristics of the base resin such as moldability and heat- resistance by compounding a polyarylene sulfide resin with two specific kinds of organic compounds in combination. CONSTITUTION:The objective composition is produced by compounding (A) 100 pts.wt. of a polyarylene sulfide resin with (B) 0.03-3 pts.wt. of a compound selected from a benzotriazole compound [e.g. 2-(2'-hydroxy-5'-methyl-phenyl) benzotriazole], a benzophenone compound (e.g. 2,4-dihydroxybenzophenone) and an aromatic benzoate compound (e.g. p-t-butylphenyl salicylate) and (C) 0.03-3 pts.wt. of a piperidine compound having steric hindrance (e.g. 4- acetoxy-2,2,6,6-tetramethylpiperidine). The component A is preferably a linear PPS homopolymer containing p-phenylene sulfide(PPS) as the recurring unit.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyarylene sulfide resin composition having improved resistance to light discoloration.

[0002]

2. Description of the Related Art In recent years,
For electric / electronic equipment parts materials, automobile equipment parts materials, chemical equipment parts materials, etc., flame-retardant thermoplastic resins having excellent mechanical properties, heat resistance, chemical resistance, etc. have been required. ing. A polyarylene sulfide resin (hereinafter abbreviated as PAS resin) typified by a polyphenylene sulfide resin (hereinafter abbreviated as PPS resin) is also one of the resins satisfying this demand, and its demand has been increasing in recent years. By the way, in the conventional PAS resin, as a production method thereof, a low-molecular weight polymer having low moldability is once prepared, and the polymer is positively oxidized to have a high molecular weight by an oxidative cross-linking or thermal cross-linking reaction to increase its viscosity to improve physical properties and moldability Therefore, it is generally difficult to obtain a molded product which has a high whiteness and can be toned in any color because the resin itself exhibits a black or dark brown color. Significant progress has been made, and it has become possible to obtain a high molecular weight PAS resin having a linear structure or a partially branched structure without substantially performing an oxidative crosslinking reaction or a thermal crosslinking reaction (for example, JP-A-61-7322, Same as 61-667
No. 20), improvement in moldability and general physical properties, and in addition, it has become possible to obtain resins having particularly high whiteness. However, this resin, when used under sunlight or fluorescent light after molding,
Discoloration progresses under the influence of heat and light, hue changes during use after molding, and non-uniformity of hue (color unevenness)
Even if you obtain a molded product with good initial whiteness without damaging the aesthetics of the molded product, it is the fact that the appearance quality deteriorates due to discoloration. This phenomenon is caused by indirect sunlight and fluorescent lighting. Such relatively weak light poses a problem for long-term use, and it is desired to improve it because it is a phenomenon that is rarely seen in other resins.

[0003]

The present inventor maintains the excellent moldability, heat resistance, solvent resistance, flame retardancy, mechanical properties and the like of PAS resin compositions, particularly PPS resin compositions, and As a result of diligent studies to obtain a resin composition having a high whiteness and a significantly improved discoloration tendency to light and a stable hue, as a result, it is possible to improve the discoloration property by combining two kinds of specific organic compounds in the PAS resin. The inventors have found that the initial whiteness and the color tone can be maintained even when they are suppressed, and the present invention has been completed. That is, the present invention relates to (A) 100 parts by weight of a polyarylene sulfide resin, and (B) 0.03 to 3 parts by weight of at least one compound selected from a benzotriazole compound, a benzophenone compound and an aromatic benzoate compound (C). The present invention relates to a photo-tarnish-resistant polyarylene sulfide resin composition containing 0.03 to 3 parts by weight of a sterically hindered piperidine compound.

Each component of the composition of the present invention will be described below. The base resin in the present invention is (A) PAS resin, which is a polymer containing 70 mol% or more of the repeating unit represented by-(Ar-S)-(where Ar is an arylene group), and its representative substance Is a PPS having a repeating unit represented by the structural formula-(Ph-S)-(wherein Ph is a phenylene group) in an amount of 70 mol% or more. Among them, the melt viscosity measured under conditions of temperature of 310 ° C and shear rate of 1200 / sec is 100 to 20000 poise, especially 300 to 50 poise.
Those in the range of 00 poise are suitable. The preferred PAS resin for use in the present invention is a polymer containing a paraphenylene sulfide unit as a repeating unit in an amount of 70 mol% or more, more preferably 80 mol% or more. If this repeating unit is less than 70 mol%, the crystallinity, which is a characteristic of a crystalline polymer, tends to be low, and sufficient strength may not be obtained, and the toughness tends to be poor. or,
The PAS resin used in the present invention may contain less than 30 mol% of other copolymerized constitutional units, for example, metaphenylene sulfide units, orthophenylene sulfide units,
p, p'-diphenylene ketone sulfide unit, p, p'-diphenylene sulfone sulfide unit, p, p'-biphenylene sulfide unit, p, p'-diphenylene ether sulfide unit, 2,6-naphthalene sulfide unit, etc. Is mentioned. Particularly, as the PAS resin used in the present invention, a substantially linear PPS homopolymer having a repeating unit of paraphenylene sulfide and a repeating unit of metaphenylene sulfide at 70 mol% or more of a repeating unit of paraphenylene sulfide as a copolymerization component. A PPS copolymer having a substantially linear structure is particularly preferable. Further, as the polyarylene sulfide resin of the present invention, in addition to the above-mentioned substantially linear polymer, a small amount of a monomer having three or more functional groups such as polyhalobenzene as a part of the monomer is mixed and polymerized. A branched or crosslinked polyarylene sulfide resin can also be used, or a PAS obtained by branching a linear polyarylene sulfide resin with a branching agent such as an alkoxysilane compound can be used. Alternatively, a blended resin obtained by blending this with the above-mentioned linear polymer can also be used, which is preferable. However, as described above, the PAS resin as the component (A) used in the present invention increases the melt viscosity of a linear polymer having a relatively low molecular weight, which has been conventionally generally used, by oxidative crosslinking or thermal crosslinking, thus improving the moldability. The improved polymer is not preferred for use in the present invention because it is already colored black or dark brown.

Next, the substance added as the component (B) in the present invention is a benzotriazole compound, a benzophenone compound or an aromatic benzoate compound,
At least one kind or two or more kinds of them are blended. Examples of these substances include the following.

That is, as the benzotriazole-based substance, 2- (2'-hydroxy-5'-methyl-phenyl) benzotriazole and 2- (2'-hydroxy-) are used.
3 ', 5'-di-t-butyl-phenyl) benzotriazole, 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-
3 ', 5'-di-isoamyl-phenyl) benzotriazole, 2- [2-hydroxy-3,5-bis- (α, α-dimethylbenzyl) phenyl] benzotriazole, 2-
(2'-hydroxy-4'-octoxyphenyl) benzotriazole etc. are mentioned. Further, as the benzophenone-based substance, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-
4-dodecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-
4-methoxy-5-sulfobenzophenone, 2-hydroxy-4-oxybenzylbenzophenone and the like can be mentioned. Further, as the aromatic benzoate-based substance, pt-
Butyl phenyl salicylate, p-octyl phenyl salicylate, etc. are mentioned. The blending amount of the component (B) is 0.03 to 3 parts by weight, preferably 0.05 to 2 parts by weight, relative to 100 parts by weight of the component (A). If the amount is too small, the desired effect on the resistance to light discoloration cannot be obtained, and if the amount is too large, the effect reaches the equilibrium, and rather the mold contamination and mechanical properties are adversely affected.

Next, the PAS resin composition of the present invention is
It is characterized in that a sterically hindered piperidine compound is used as the component (C) together with the component (B), and it has a remarkable synergistic effect on photochromic resistance. The sterically hindered piperidine compound used herein is a piperidine or a derivative thereof having a sterically hindered group such as an alkyl group, and if its example is shown, 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy-2,2,6,6-
Tetramethylpiperidine, 4-methoxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,
6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6, 6-tetramethylpiperidine, 4- (phenylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine, bis (2,2,6,6-tetramethyl-4-piperidyl) oxalate, bis (2,2 , 6,6-Tetramethyl-4-piperidyl) malonate, bis (2,2,6,6-tetramethyl-4-piperidyl) adipate, bis (2,2,6,
6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl)
Terephthalate, 1,2-bis- (2,2,6,6-tetramethyl-4-piperidyloxy) ethane, bis- (2,2,6,6
-Tetramethyl-4-piperidyloxy) hexamethylene-1,6-dicarbamate, bis (1-methyl-2,2,6,
6-tetramethyl-4-piperidyl) adipate, tris (2,2,6,6-tetramethyl-4-piperidyl) benzene-1,3,5-tricarboxylate and the like. Further, high molecular weight piperidine derivative polycondensates such as dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate of succinate are also effective. The amount of the component (C) used here is also 0.03 to 3 parts by weight, preferably 0.05 to 2 parts by weight, per 100 parts by weight of the component (A). If the amount of component (C) is too small, the anti-discoloration effect cannot be expected, and even if it is added unnecessarily excessively, it is not effective and economically disadvantageous. It is not preferable because it causes defects such as contamination.

Next, the composition of the present invention is not necessarily an essential component, but is excellent in performance such as mechanical strength, rigidity, heat resistance, dimensional stability (deformation resistance, warpage), and electrical properties. To obtain a product, it is preferable to add a filler,
For this purpose, a fibrous, powdery or plate-like filler is used depending on the purpose. As the fibrous filler, glass fiber, asbestos fiber, silica fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber,
Potassium titanate fiber, stainless steel, aluminum,
Inorganic fibrous substances such as metallic fibrous substances such as titanium, copper and brass can be used. A particularly representative fibrous filler is glass fiber or potassium titanate fiber. Note that high-melting-point organic fibrous substances such as aromatic polyamide and acrylic resin can also be used. On the other hand, as the granular filler, silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, silicates such as wollastonite, iron oxide, Oxides of metals such as alumina, calcium carbonate,
Examples thereof include metal carbonates such as magnesium carbonate, calcium sulfates, metal sulfates such as barium sulfate, silicon carbide, silicon nitride, boron nitride, and various metal powders.
Examples of the plate-like filler include mica, glass flakes, various metal foils and the like. These inorganic fillers can be used alone or in combination of two or more. The combined use of fibrous fillers, particularly glass fibers or potassium titanate fibers, with granular and / or plate-like fillers is a preferable combination particularly in terms of mechanical strength, dimensional accuracy, electrical properties and the like. When using these fillers, it is desirable to use a sizing agent or a surface treatment agent if necessary. Examples of this are functional compounds such as epoxy compounds, isocyanate compounds, silane compounds, and titanate compounds. These compounds may be subjected to a surface treatment or a converging treatment in advance, or may be added at the same time when the material is prepared. The amount of the filler used is 400 parts by weight or less, preferably 200 parts by weight or less, per 100 parts by weight of the PAS resin as the component (A). If it is less than 10 parts by weight, the mechanical strength and rigidity will be slightly inferior, and if it is too large, molding will be difficult and there will be problems with the mechanical strength of the molded product.

In addition to the above-mentioned components, other thermoplastic resins may be supplementarily used in a small amount in the composition of the present invention depending on the purpose. Any other thermoplastic resin may be used as long as it is a thermoplastic resin that is stable at high temperatures. For example, aromatic polyester polymers such as polyethylene terephthalate, polybutylene terephthalate, etc. and aromatic dicarboxylic acids and diols or oxycarboxylic acids, polyamide polymers such as nylon 66, nylon 6, nylon 12, nylon 46, and various polyolefins. Polymer, polycarbonate,
Examples thereof include ABS, polyphenylene oxide, polyalkyl acrylate, polyacetal, polysulfone, polyethersulfone, polyetherimide, polyetherketone and the like. Further, these thermoplastic resins may be used as a mixture of two or more kinds. Furthermore, in the composition of the present invention, a known substance generally added to a thermoplastic resin, that is, a stabilizer such as an antioxidant, an antistatic agent,
A flame retardant, a coloring agent such as a dye / pigment, a lubricant and a crystallization accelerator, a crystal nucleating agent and the like can be appropriately added depending on the required performance. In particular, when the PAS resin composition of the present invention is blended with an arbitrary pigment to obtain a molded product having a desired hue, it maintains the hue and there is little discoloration during use, and the value of the molded product is greatly improved. It enhances. In particular, white type molded articles using various white pigments such as titanium oxide, zinc oxide and the like are prone to discoloration and uneven color, and the composition of the present invention is suitable for white type molded articles using such white pigments. On the other hand, it is particularly effective in preventing discoloration, and is extremely effective in maintaining its color tone and quality.

The polyarylene sulfide resin composition of the present invention can be prepared by the equipment and method generally used for preparing a synthetic resin composition. That is, necessary components are mixed, kneaded using a single-screw or twin-screw extruder, and extruded into molding pellets, and a method of mixing and molding a part of the necessary components as a masterbatch,
Further, in order to improve dispersion and mixing of the respective components, it is possible to pulverize a part or all of the resin components, mix them, and melt-extrude. Further, if necessary, an adhesive, a dispersant or the like is used to adhere pigments and other components to the surface of the molding pellets prepared in advance by a method called surface coating, and the molded pellets are molded to obtain a molded composition of the present invention. It is also possible to use

[0011]

The PAS resin composition of the present invention has heat resistance,
Excellent mechanical properties, moldability, etc., especially discoloration due to sunlight, fluorescent light, etc. when used after molding, color unevenness etc. are small, initial color tone and quality are maintained, and such characteristics are required. It is extremely useful as a molded product, especially a colored molded product.

[0012]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Examples 1 to 10 and Comparative Examples 1 to 9 (A) As a component, polyphenylene sulfide resin (PP
S, manufactured by Kureha Chemical Industry Co., Ltd., product name "Fortron KPS")
On the other hand, as shown in Table 1, B-shown below as the component (B)
Any one of 1, B-2, B-3, B-4, and C-1, C-2 as the component (C)
Was added and premixed for 5 minutes with a Henschel mixer, and this was melt-kneaded with an extruder having a cylinder temperature of 310 ° C. to prepare pellets of the PPS resin composition. Next, plate-shaped test pieces were molded from these pellets with an injection molding machine at a cylinder temperature of 320 ° C and a mold temperature of 150 ° C.
The initial hue L, a, b values (L ₀ , a ₀ , b ₀ ) were measured using a color difference meter Z-300A manufactured by K.K. Then, this test piece was subjected to the conditions described below for the hue L, a,
The b value (L ₁ , a ₁ , b ₁ or L ₂ , a ₂ , b ₂ ) was measured. From these values, ΔE ₁ or ΔE ₂ was calculated by the following formula (1) or (2) according to the conventional method to obtain the degree of color change. In addition, as shown in Table 1 as a comparative example, a test piece was similarly molded from a composition in which the component (B) or the component (C) and both of them were not mixed, and the degree of discoloration was similarly obtained.

[0013]

[Equation 1]

The test methods used for evaluation in Examples and the like are as follows. Sunshine fade test Sunshine fade meter (Suga Test Instruments Co., WEL-
SUN-HCH type) was used, ultraviolet rays were irradiated at a black panel temperature of 83 ° C., and after 60 hours had elapsed, the samples were taken out and L, a, b values (L ₁ , a ₁ , b ₁ ) were measured. Fluorescent light exposure test Place the test piece at a position 10 cm from the surface of the 36-watt tubular fluorescent lamp, turn it on at room temperature for 2 months, and then remove the test piece.
The L, a and b values (L ₂ , a ₂ and b ₂ ) were measured. The results are shown in Table 1.

Examples 11 to 15 and Comparative Examples 10 to 14 In addition to the components (A), (B) and (C) of the above Examples and Comparative Examples,
Further, Table 2 shows the results of the same test in the case where glass fiber and titanium white (average particle size of about 1 μm) were blended as shown in Table 2 as a white pigment.

[0016]

[Table 1]

[0017]

[Table 2]

* 1 B-1: 2- [2-hydroxy-3,5-
Bis (α, α-dimethylbenzyl) phenyl] benzotriazole B-2: 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole B-3: 2-hydroxy-4-methoxybenzophenone B -4: 2,4-di-t-butylphenyl-3,5-di-t-
Butyl-4-hydroxybenzoate * 2 C-1: bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate C-2: dimethyl-1- (2-hydroxyethyl) -4-hydroxy succinate -2,2,6,6-Tetramethylpiperidine polycondensate As is clear from the above results, the composition molded article in which the components (B) and (C) of the present invention are used in combination is the case in which these are not added at all. As a matter of course, compared with the case where each of them is used alone, the discoloration degree (ΔE) is low even though the total amount is the same or less, and a remarkable synergistic effect is recognized.

Claims (2)

[Claims] 1. 0.03 to 3 parts by weight of at least one compound selected from (B) a benzotriazole compound, a benzophenone compound and an aromatic benzoate compound in 100 parts by weight of (A) polyarylene sulfide resin. A photochromic polyarylene sulfide resin composition comprising 0.03 to 3 parts by weight of a sterically hindered piperidine compound. 2. The photochromic polyarylene sulfide resin composition according to claim 1, wherein the polyarylene sulfide resin (A) has substantially no branching or cross-linking structure due to oxidative crosslinking or thermal crosslinking reaction.