JP3021868B2 - Polyarylene sulfide resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyarylene sulfide resin composition. More specifically, the present invention relates to a polyarylene sulfide resin composition having an improved crystallization rate and excellent moldability.

[0002]

2. Description of the Related Art In recent years,
Electrical and electronic equipment parts materials, automotive equipment parts materials, chemical equipment parts materials, etc., are required to have excellent mechanical properties, heat resistance, chemical resistance, etc., and flame-retardant thermoplastic resins. ing. A polyarylene sulfide resin typified by polyphenylene sulfide is one of the resins meeting this demand, and the demand has been growing in recent years. However, this resin is crystalline in nature, but when processed by injection molding or the like, the crystallization rate is lower than that of ordinary crystalline thermoplastic resins such as polyacetal resin and polybutylene terephthalate resin. Crystallization does not progress, causing uneven crystallization shrinkage during processing or use after molding, causing inconvenience such as deformation, and the surface condition of the molded article is not good. Therefore, in general, it is necessary to use a mold having a considerably high temperature (for example, 140 ° C. or higher), which causes not only a problem (eg, safety) in the molding operation but also a disadvantage such as a long molding cycle. In order to solve these problems, the following method has recently been proposed as a technique for performing high-speed crystallization using a relatively low-temperature mold. (1) Add an oligomeric ester (Japanese Patent Laid-Open No.
No. 4) (2) Addition of another thioether (JP-A-62-230849) (3) Addition of a carboxylic acid ester (JP-A-62-230848)
(4) Add a certain phosphate ester (Japanese Patent Laid-Open No. 62-23 / 1987)
No. 0850, JP-A-1-225660, JP-A-3-9156
(No. 3) (5) Add a certain silicon compound containing a mercapto group (JP-A-2-225565) (6) Add other common nucleating agents However, these methods involve the inventors and others. As a result of the examination,
If the crystallization promoting effect is not sufficient or if a large amount is added in order to enhance the effect, evaporating gas or decomposition gas of the compounding agent or resin will be generated at the time of molding or use, and it will adhere to and contaminate the mold and the environment. There are practical problems such as inconveniences such as deterioration and adverse effects on physical properties.

[0003]

Means for Solving the Problems The present inventors have made the conventional injection molding by increasing the crystallization rate at the time of melting and solidifying a polyarylene sulfide resin composition, particularly a polyphenylene sulfide resin composition. Eliminates the need for a high mold temperature, which is considered a disadvantage, and has a high degree of crystallinity even when molded at a low mold temperature.In addition, there is no evaporation or decomposition gas generated during extrusion or molding, and various physical properties As a result of intensive studies to obtain a composition having no adverse effect, a composition in which a specific alkyl mercaptan is blended with a crystal nucleating agent ,
The addition of a relatively small amount increases the crystallization rate, shows higher crystallinity at a lower mold temperature than before, shortens the molding cycle, and has almost no adverse effect on gas generation during processing. It was found that the physical properties were maintained without any effect, and the present invention was completed. That is, the present invention relates to (A) 100 parts by weight of a polyarylene sulfide resin, (B) 0.1 to 10 parts by weight of a specific alkyl mercaptan, (C) 0 to 400 parts by weight of an inorganic filler, and (D) crystal nucleating agent of 0.002 to 5 parts by weight. It is a polyarylene sulfide resin composition obtained by blending parts . According to the study by the present inventors, it is expressed by the following equation (1).
It has been found that the combined use of a specific alkyl mercaptan (B) and a nucleating agent (D) that positively generates crystal nuclei has a further effect on increasing the crystallization rate at a low mold temperature. That said (A), (B), the component (C), further (D) by blending the 0.002 parts by weight nucleating agent polyarylene sulfide resin composition exhibits a crystallization promoting effect of one layer, It is possible to significantly reduce the temperature of the mold during molding.

[0004] The components constituting the composition of the present invention will be described below. In the present invention, the resin serving as the base is the polyarylene sulfide resin (A) having a structural formula of -Ar-S-
(Where Ar is an arylene group)
A polymer containing 70 mol% or more (hereinafter abbreviated as PAS), and its representative substance is represented by the structural formula -Ph-S-
Ph is a phenylene group) 70 mol%
It is a polyphenylene sulfide having the above. Among them, those having a melt viscosity of 10 to 20,000 poise, particularly 100 to 5,000 poise, measured at a temperature of 310 ° C. and a shear rate of 1200 / sec are suitable. The PAS resin is generally known to have a substantially linear molecular structure having no branched or crosslinked structure and a structure having a branched or crosslinked structure according to the production method. It is also effective for PA preferred for use in the present invention
The S resin is a homopolymer or a copolymer containing 70 mol% or more, more preferably 80 mol% or more of paraphenylene sulfide units as repeating units (hereinafter referred to as PPS).
Abbreviation). If the content of the repeating unit is less than 70 mol%, the original crystallinity, which is a characteristic of a crystalline polymer, tends to be low, and sufficient mechanical properties tend not to be obtained. Examples of the copolymerizable structural unit include a metaphenylene sulfide unit, an orthophenylene sulfide unit,
p, p'-diphenylene ketone sulfide unit, p,
p′-diphenylene sulfone sulfide unit, p, p ′
-Biphenylene sulfide unit, p, p'-diphenylene ether sulfide unit, and 2,6-naphthalene sulfide unit. Particularly, as the PAS resin used in the present invention, a substantially linear PPS homopolymer having a repeating unit composed of paraphenylene sulfide and a PPS copolymer composed of metaphenylene sulfide having a repeating unit composed of paraphenylene sulfide within 20 mol% are preferred. Further, as the polyarylene sulfide resin of the present invention, in addition to the above-mentioned substantially linear polymer, a branched or cross-linked polyarylene sulfide resin polymerized by using a small amount of a monomer having three or more functional groups as a part of the monomer is used. It is also possible to use a blended resin obtained by blending this with the linear polymer. Further, as the PAS resin as the component (A) used in the present invention, a polymer obtained by increasing the melt viscosity of a linear polymer having a relatively low molecular weight by oxidative crosslinking or thermal crosslinking and improving moldability can be used.

The alkyl mercaptan added as the component (B) in the present invention is a compound having an alkyl mercapto group in the molecule, and is particularly represented by the following formula (1) from the viewpoint of the crystallization promoting effect and the volatility. The compounds represented are effective.

[0006]

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(Wherein -R ₁ -is a divalent group represented by -C _m H _2m - or -C _m H _2m COO-, -R ₂ is an n-valent hydrocarbon group, and n is 1 to
4, m is an integer of 1 or more, and the total number of carbon atoms per molecule of the compound of the formula (1) is from 8 to 32. In particular, in the formula (1), R ₁ is an alkylene group, R ₂ is an alkyl group, and n is 1 to
4, preferably 1 to 2, and the total number of carbon atoms in one molecule is 8 to 3
2, preferably 10 to 25 alkyl mercaptans, or R ₁
Is a —C _m H _2m COO— group having 3 to 18 carbon atoms (m), and R ₂ has ₂ to ₂ carbon atoms.
Alkyl mercapto group-containing compounds having a structure consisting of 1 to 4 valent hydrocarbon groups (n is 1 to 4) in 14 are preferably used. In general, such alkyl mercaptans having a low molecular weight are not preferable because they have volatility and cause problems during molding. Therefore, the alkyl mercaptan suitably used in the present invention has at least 8 or more carbon atoms, preferably
It is 10 or more, more preferably 12 or more. Specific examples include n-octyl mercaptan, n-lauryl mercaptan, n-stearyl mercaptan, octyl γ-
Mercaptopropionate, stearyl γ-mercaptopropionate, pentaerythrityltetrakis (γ-
Mercaptopropionate) and the like. The amount of the alkyl mercaptan (B) used in the present invention is 0.1 to 10 parts by weight per 100 parts by weight of the PAS resin,
Preferably it is 0.2 to 8 parts by weight. If the amount is too small, the intended effect cannot be obtained originally. If the amount is too large, it is not preferable because odor is generated and the physical properties are affected.

Next, the inorganic filler (C) used in the present invention
Is not an essential component, but its mechanical properties,
In order to obtain a molded article having excellent properties such as heat resistance, dimensional stability (deformation resistance, warpage), and electrical properties, it is preferable to blend the composition, which may be in the form of fibers, powders, or plates depending on the purpose. Is used. Examples of the fibrous filler include glass fiber, asbestos fiber, carbon fiber, silica fiber, silica / alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, stainless steel, aluminum, titanium, Inorganic fibrous substances such as fibrous materials of metals such as copper and brass are exemplified. Particularly typical fibrous fillers are glass fibers or carbon fibers. Note that a high-melting organic fibrous substance such as an aromatic polyamide, a fluorine resin, or an acrylic resin can also be used. On the other hand, as the granular filler, carbon black, silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay,
Silicates such as diatomaceous earth, wollastonite, metal oxides such as iron oxide, titanium oxide, zinc oxide and alumina;
Examples include metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, silicon carbide, boron nitride, and various metal powders. Examples of the plate-like filler include mica, glass flake, various metal foils, and the like. These inorganic fillers can be used alone or in combination of two or more. The combined use of a fibrous filler, especially a glass fiber or a carbon fiber, and a granular and / or plate-like filler is a preferable combination, particularly in terms of having both 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. This example is a functional compound such as an epoxy compound, an isocyanate compound, a silane compound and a titanate compound. These compounds may be used after the filler is subjected to a surface treatment or a convergence treatment, or may be added simultaneously with the preparation of the material. The amount of inorganic filler used is PAS resin of component (A) 1
400 parts by weight or less per 100 parts by weight, preferably 10 to
300 parts by weight. If the amount is less than 10 parts by weight, the mechanical strength and rigidity are inferior, which is not preferable depending on the use of the molded article. If it is too large, the molding operation becomes difficult and there is a problem in the mechanical properties of the molded product.

As described above, the crystallization rate of the composition of the present invention is further increased by adding and using a nucleating agent (D), and the effect of the present invention is further increased. As the crystal nucleating agent used for this purpose, any of known organic nucleating agents and inorganic nucleating agents can be used. As minerals, such as Zn powder, Al powder, graphite, or alone such as carbon _{black, ZnO, MgO, Al 2 O} 3, TiO 2, Mn
_{O 2, SiO 2, Fe 3} O 4 metal oxides such as, nitrides such as boron _{nitride, Na 2 CO 3, CaCO 3} , MgCO 3, CaSO 4, Ca
Examples include inorganic salts such as SiO ₃ , BaSO ₄ , and Ca ₃ (PO ₄ ) ₃ , silica, talc, kaolin, clay, and clay. As the organic substance, use is made of organic salts such as calcium oxalate, sodium oxalate, calcium benzoate, calcium phthalate, calcium tartrate, magnesium stearate, heat-resistant polymers, and cross-linked heat-resistant polymers. be able to. Particularly preferred are boron nitride; or clays such as talc, kaolin, clay and clay; and high molecular compounds having a crosslinked or branched structure.
Here, the high molecular compound having a crosslinked or branched structure is, for example, a high molecular compound having a branched or crosslinked structure generated by polycondensation of a monomer having three or more functional groups in a part of the monomer, or an existing polymer The substance may be either a substance obtained by adding a crosslinked structure or a branched structure later, or a crosslinked PAS. Some of the above nucleating agents overlap with the inorganic filler (C), and these substances can perform both functions.However, the amount of the nucleating agent used is 0.002 parts by weight per 100 parts by weight of the PAS resin. It is sufficient if the amount is 5 to 5 parts by weight, and preferably 0.02 to 2 parts by weight. If the amount is less than 0.002 parts by weight, the effect of increasing the crystallization rate is not sufficient.

Further, as the base resin of the present invention, it is possible to use a small amount of another thermoplastic resin in an auxiliary manner as long as its purpose is not hindered. The other thermoplastic resin used here may be any thermoplastic resin that is stable at high temperatures. For example, an aromatic polyester resin such as polyethylene terephthalate and polybutylene terephthalate, which is composed of an aromatic dicarboxylic acid and a diol or oxycarboxylic acid, nylon 6, nylon 6-6, nylon 6-10, nylon 12, nylon 4
6, polyamide-based resin such as ethylene, propylene, butene and other olefin-based resin, polystyrene,
Examples include polystyrene-acrylonitrile, styrene resins such as ABS, polycarbonate, polyphenylene oxide, polyalkyl acrylate, polyacetal, polysulfone, polyethersulfone, polyetherimide, polyetherketone, and fluororesin. These thermoplastic resins can be used as a mixture of two or more kinds.

Furthermore, the composition of the present invention may contain known additives which are generally added to thermoplastic resins, such as stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, flame retardants, dyes and pigments, and the like. , A colorant, a lubricant, a release agent, and the like can be appropriately added according to required performance.

The polyarylene sulfide resin composition of the present invention can be prepared by equipment and a method generally used for preparing a synthetic resin composition. That is, a method in which necessary components are mixed, kneaded using a single-screw or twin-screw extruder, and extruded into molding pellets.
Further, in order to improve the dispersion and mixing of the components, it is possible to pulverize a part or all of the polyarylene sulfide resin, mix the mixture, and extrude the mixture.

[0013]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 8 and Comparative Examples 1 to 13 Polyphenylene sulfide resin (manufactured by Kureha Chemical Co., Ltd.)
The components shown in the table were added in the amounts shown in the table to the trade name “Fortron KPS”), and premixed with a Henschel mixer for 5 minutes. In some cases, commercially available glass fiber (diameter 10μ)
m, length 3 mm) in the amount shown in the table, and add 2 with a blender.
The mixture was mixed in an extruder having a cylinder temperature of 310 ° C. to produce pellets of the polyphenylene sulfide resin composition. Next, cylinder temperature of 320
A flat plate specimen having a thickness of 3 mm and a size of 50 mm × 70 mm was molded at a mold temperature shown in the table at a temperature of ℃, left at room temperature for a certain period of time, and then using a rad-rd X-ray diffractometer of Rigaku Denki Co., Ltd. The crystallinity was measured. The molded pieces were adjusted for 24 hours in an atmosphere of room temperature (23 ° C.) and a humidity of 50%, and measured for dimensions. Then, the molded pieces were annealed at 150 ° C. for 3 hours, the dimensions were measured, and the post-shrinkage was calculated.
Also, visually observe the surface gloss of the molded product,
Possible, impossible ranking. In addition, the releasability at the time of molding was evaluated and ranked similarly. The tensile strength and elongation were measured by ASTM D-638. The results are shown in Tables 1 to 3. The components (B) and (D) used in this example are as follows. B-1 HS-C ₁₈ H ₃₇ B-2 HS-C ₁₂ H ₂₅

[0015]

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B-4 HS-C ₂ H ₄ COOC ₈ H ₁₇ D-1 Boron nitride D-2 Talc D-3 Kaolin

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

[0020]

The specific alkyl mercaptans of the present invention and
The polyarylene sulfide resin composition containing a specific amount of a nucleating agent and a crystal nucleating agent has a remarkable crystallization accelerating effect, and a molded article having a sufficient crystallinity can be obtained even when a relatively low temperature mold is used in molding. The molding workability (safety etc.) is improved, the molding cycle can be shortened, dimensional changes due to shrinkage due to irregular crystallization after molding, warpage, etc. are also improved, and the surface of the molded product is also improved. Good condition and physical properties can be obtained. These effects are further improved by the combined use of a nucleating agent substance.

Continuation of front page (56) References JP-A-2-225565 (JP, A) JP-A-3-227369 (JP, A) JP-A-1-266160 (JP, A) JP-A-5-32879 (JP) U.S. Pat. No. 3,386,950 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 81/00-81/02 C08K 5/36-5/372

Claims (2)

(57) [Claims] (1) Polyarylene sulfide resin (A)
100 parts by weight of (B) one or more alkyl mercaptans selected from the group consisting of compounds represented by the following formula (1)
A polyarylene sulfide resin composition comprising 0.1 to 10 parts by weight and (C) 0 to 400 parts by weight of an inorganic filler (D) 0.002 to 5 parts by weight of a crystal nucleating agent . Embedded image (Wherein -R ₁ -is a divalent group represented by -C _m H _2m -or -C _m H _2m COO-, -R ₂ is an n-valent hydrocarbon group, n is 1 to 4, and m is It is an integer of 1 or more, and the total number of carbon atoms per molecule of the compound of the formula (1) is from 8 to 32.) 2. The method according to claim 1, wherein (D) the nucleating agent is boron nitride or chao.
Phosphorus, talc, clay and high with crosslinked or branched structures
One or more kinds selected from molecular compounds.
2. The polyarylene sulfide resin composition according to 1.