JP2007204615A - Polyarylene sulfide resin composition for molded article having box shape and molded article having box shape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyarylene sulfide resin composition for molded articles having a box shape, excellent in moldability and mechanical strength and excellent in flatness of a bottom part of a box shape part and suppressed in dimensional dispersion of molded articles obtained by shot molding. <P>SOLUTION: The resin composition is obtained by formulating (A) a polyarylene sulfide resin having 10-100 Pa s melting viscosity in 1,200 sec<SP>-1</SP>shear rate at 310°C and having ≤210°C crystallization temperature with (B) an inorganic filler, composed of fibrous filler and non-fibrous filler and containing 25-75 wt.% fibrous filler, in an amount of 40-70 wt.% based on the composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a polyarylene sulfide resin composition for a molded product having a box shape with excellent moldability and mechanical strength, excellent flatness of the bottom surface of the box-shaped portion, and reduced dimensional variation between shots. About.

  Polyarylene sulfide (hereinafter sometimes abbreviated as PAS) resin, represented by polyphenylene sulfide (hereinafter sometimes abbreviated as PPS) resin, has high heat resistance, mechanical properties, chemical resistance, dimensional stability, flame resistance Therefore, it is widely used for automotive equipment part materials, electrical / electronic equipment part materials, chemical equipment part materials, and the like. On the other hand, with the recent high performance and high integration of various parts such as automobile equipment or electrical / electronic equipment, demands for dimensional accuracy of materials are also increasing. As one of such parts, there is a part having a box shape such as a case part of an ECU or a power module of an automobile. As described above, PAS resin has higher dimensional accuracy than other resins and is used in such parts. However, higher dimensional accuracy is required, and in particular, the flatness of the bottom portion of the box-shaped portion is improved. It has become necessary to suppress dimensional variations between shots.

As a conventional method for solving this problem, an attempt is made to improve the molding method or the material surface. As a molding technique, for example, an injection compression molding method or the like is known (for example, Patent Document 1). However, this method cannot be carried out with a conventional injection molding machine as it is, and there is a drawback in that it is difficult to introduce it as a general-purpose technique due to a problem of cost increase such as remodeling. As an improvement in the material aspect, Patent Document 2 discloses a PAS resin composition in which a fibrous filler and a non-fibrous filler are blended at the same time, and more non-fibrous filler is blended than the fibrous filler. Although a product is disclosed, excellent moldability, mechanical strength, flatness, and suppression of dimensional variation between shots cannot be satisfied at the same time.
JP 2002-187177 A JP 2003-301108 A

  The present invention solves the above-mentioned problems of the prior art, is excellent in moldability and mechanical strength, has high flatness, suppresses dimensional variation between shots, and is suitably used for a molded product having a box shape. The object is to provide a PAS resin composition.

  As a result of intensive studies to achieve the above object, the present inventors have used a specific PAS resin and combined a specific amount of a fibrous filler and a non-fibrous filler in a specific ratio, thereby achieving the above object. As a result, it was found that a PAS resin composition for molded articles having a box shape in which the above was achieved was obtained, and the present invention was completed.

That is, the present invention
(A) For a polyarylene sulfide resin having a resin temperature of 310 ° C., a melt viscosity at a shear rate of 1200 sec ⁻¹ of 10 to 100 Pa · s, and a crystallization temperature of 210 ° C. or less,
(B) An inorganic filler composed of a fibrous filler and a non-fibrous filler is blended in an amount of 40 to 70% by weight (in the composition), and (B) the ratio of the fibrous filler in the inorganic filler is 25 to 75. A polyarylene sulfide resin composition for molded articles having a box shape that is% by weight, and a molded article having a box shape formed by molding the polyarylene sulfide resin composition.

  According to the present invention, it is possible to provide a PAS resin composition that is excellent in moldability and mechanical strength, has high flatness, suppresses dimensional variation between shots, and is suitably used for a molded product having a box shape. .

  Hereinafter, the constituent components of the present invention will be described in detail. The PAS resin as the component (A) used in the present invention is mainly composed of — (Ar—S) — (wherein Ar is an arylene group) as a repeating unit. Examples of the arylene group include p-phenylene group, m-phenylene group, o-phenylene group, substituted phenylene group, p, p′-diphenylene sulfone group, p, p′-biphenylene group, and p, p′-di. A phenylene ether group, p, p′-diphenylenecarbonyl group, naphthalene group, and the like can be used. In this case, among the arylene sulfide groups composed of the above-mentioned arylene groups, in addition to a polymer using the same repeating unit, that is, a homopolymer, a copolymer containing different repeating units from the viewpoint of processability of the composition May be preferred.

  As the homopolymer, a homopolymer having a p-phenylene sulfide group as a repeating unit using a p-phenylene group as an arylene group is preferably used. As the copolymer, among the arylene sulfide groups comprising the above-mentioned arylene groups, two or more different combinations can be used, and among them, a combination containing a p-phenylene sulfide group and an m-phenylene sulfide group is particularly preferably used. It is done. Among these, those containing 70 mol% or more, preferably 80 mol% or more of p-phenylene sulfide groups are suitable from the viewpoint of physical properties such as heat resistance, moldability and mechanical properties.

  Among these PAS resins, a high molecular weight polymer having a substantially linear structure obtained by condensation polymerization from a monomer mainly composed of a bifunctional halogen aromatic compound can be preferably used.

The PAS resin as the component (A) used in the present invention must have a melt viscosity of 10 to 100 Pa · s at a resin temperature of 310 ° C. and a shear rate of 1200 sec ⁻¹ , preferably 10 to 50 Pa · s. . When the melt viscosity is higher than 100 Pa · s, the fluidity is insufficient and the moldability is inferior, and when it is less than 10 Pa · s, problems occur during molding.

  The PAS resin as the component (A) used in the present invention needs to have a crystallization temperature of 210 ° C. or lower. If the crystallization temperature is too high, dimensional variation between shots increases. Such a PAS resin used in the present invention does not depend on its production method as long as the crystallization temperature is 210 ° C. or lower, but one example of the production method is obtained by the following washing method.

  That is, after the polymerization is completed, the reaction mixture is cooled to near room temperature, the contents are passed through a 100 mesh screen, the particulate polymer is filtered, and then washed 2-4 times with acetone and 4-8 times with ion-exchanged water. The above-mentioned polymer can be obtained by performing.

  Next, the inorganic filler as the component (B) used in the present invention is a fibrous filler and a non-fibrous filler, and the fibrous filler decreases the molding shrinkage and linear expansion coefficient of the molded product, It has the effect of improving mechanical properties, and the non-fibrous filler reduces the molding shrinkage rate and the shrinkage rate anisotropy of the molded product.

  Examples of the fibrous filler include glass fiber, asbestos fiber, carbon fiber, silica fiber, silica / alumina fiber, zirconia fiber, boron nitride fiber, boron fiber, potassium titanate fiber, stainless steel, aluminum, titanium, copper, brass, etc. Examples thereof include metal fibrous materials such as metal fibrous materials, and glass fibers and carbon fibers are particularly preferably used. These fibrous fillers can be referred to as one kind or two or more kinds of pellets.

  Non-fibrous fillers include granular fillers and plate fillers, carbonates such as calcium carbonate and magnesium carbonate, talc, mica, glass beads, plate glass, silica, quartz powder, glass powder, Oxalates such as calcium oxalate, kaolin, clay, diatomaceous earth, wollastonite, oxides such as iron oxide, titanium oxide, zinc oxide and alumina, hydroxides such as magnesium hydroxide and barium hydroxide, sulfuric acid Examples thereof include sulfur oxides of metals such as calcium and barium sulfate, carbon black, granular carbon, silicon carbide, silicon nitride, boron nitride, various metal powders, metal foils and the like, and calcium carbonate and glass beads are preferably used. These non-fibrous fillers can be used alone or in combination of two or more.

  In using these inorganic fillers (B), 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 used after being subjected to surface treatment or convergence treatment in advance, or may be added at the same time as material preparation.

  Here, the blending amount of (B) inorganic filler is 40 to 70% by weight (in the composition), preferably 40 to 60% by weight. (B) When the blending amount of the inorganic filler is less than 40% by weight, the original excellent mechanical strength of the filler-reinforced PAS resin composition cannot be obtained, and when the blending amount exceeds 70% by weight, the fluidity is lowered. This causes a problem that the workability of the steel deteriorates.

  In addition, it is necessary that the ratio of the fibrous filler in the (B) inorganic filler is 25 to 75% by weight. When the proportion of the fibrous filler is less than 25% by weight, the mechanical strength inherent to the filler-reinforced PAS resin composition cannot be obtained, and when it exceeds 75% by weight, the flatness is deteriorated and the dimensional variation between shots. Becomes larger.

  Moreover, the silane compound can be mix | blended with the resin composition of this invention in order to improve a burr | flash etc. in the range which does not impair the effect of this invention. The silane compound includes various types such as vinyl silane, methacryloxy silane, epoxy silane, amino silane, mercapto silane, etc., for example, vinyl trichloro silane, γ-methacryloxy propyl trimethoxy silane, γ-glycidoxy propyl trimethoxy silane. , Γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, and the like, but are not limited thereto.

  The PAS resin composition of the present invention can be used in combination with a small amount of other thermoplastic resins in addition to the above components depending on the purpose. As the other thermoplastic resin, any thermoplastic resin that is stable at a high temperature may be used.

  Further, the PAS resin composition of the present invention includes known substances generally added to thermoplastic resins within a range not impairing the effects of the present invention, that is, stabilizers such as antioxidants, flame retardants, dyes / pigments and the like. Coloring agents, lubricants, crystallization accelerators, crystal nucleating agents, and the like can be appropriately added according to the required performance.

  The PAS resin composition of the present invention can be prepared by equipment and methods generally used for preparing a synthetic resin composition. In general, necessary components can be mixed, melt-kneaded using a single-screw or twin-screw extruder, and extruded to form pellets for molding. Also, it is one of preferred methods to melt-extrude the resin component and add and blend an inorganic filler in the middle.

  The material pellets thus obtained can be molded using generally known thermoplastic resin molding methods such as injection molding, extrusion molding, vacuum molding, compression molding, etc., but injection molding is most preferred. .

  The PAS resin composition of the present invention exhibits extremely good performance as a molded product having a box shape in each part such as automobile equipment or electrical / electronic equipment, and has a higher demand for flatness and dimensional variation between shots. It is useful as a material for a molded article having a box shape that has been difficult to satisfy.

  Next, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to these.

In addition, the specific substance of each component used by the Example and the comparative example is as follows.
・ (A) Polyphenylene sulfide (PPS) resin
(A-1)
Into a 20 L autoclave, 5700 g of NMP (N-methyl-2-pyrrolidone) was charged, and after replacing with nitrogen gas, the temperature was raised to 100 ° C. while stirring at a rotation speed of 250 rpm for about 1 hour. After reaching 100 ° C., 1170 g of a NaOH aqueous solution having a concentration of 74.7% by weight, 1990 g of an aqueous sulfur source solution (including NaSH = 21.8 mol and Na ₂ S = 0.50 mol), and NMP 1000 g were added and gradually increased to 200 ° C. over about 2 hours. Then, 945 g of water, 1590 g of NMP, and 0.31 mol of hydrogen sulfide were discharged out of the system.

  After the dehydration step, the mixture was cooled to 170 ° C., and 3459 g of p-dichlorobenzene, 2800 g of NMP, 133 g of water, and 23 g of NaOH having a concentration of 97% by weight were added. Subsequently, while stirring at a rotational speed of 250 rpm of the stirrer, the temperature was raised to 180 ° C. over 30 minutes, and further between 180 ° C. and 220 ° C. over 60 minutes. After reacting at that temperature for 60 minutes, the temperature was raised to 230 ° C. over 30 minutes, and the reaction was carried out at 230 ° C. for 90 minutes to perform pre-stage polymerization.

  Immediately after completion of the pre-polymerization, the rotation speed of the stirrer was increased to 400 rpm, and 340 g of water was injected. After water injection, the temperature was raised to 260 ° C. over 1 hour, and the reaction was carried out at that temperature for 5 hours to carry out post polymerization.

After completion of the post-polymerization, the reaction mixture is cooled to near room temperature, the contents are passed through a 100 mesh screen, the particulate polymer is filtered off, then washed with acetone three times and then with ion-exchanged water five times. A washed granular polymer was obtained. The granular polymer was dried at 105 ° C. for 13 hours. The granular polymer thus obtained had a melt viscosity (310 ° C., shear rate of 1200 sec ⁻¹ ) of 25 Pa · s and a crystallization temperature of 203 ° C.
(A'-1)
Into a 20 L autoclave, 5700 g of NMP (N-methyl-2-pyrrolidone) was charged, and after replacing with nitrogen gas, the temperature was raised to 100 ° C. while stirring at a rotation speed of 250 rpm for about 1 hour. After reaching 100 ° C., 1170 g of a NaOH aqueous solution having a concentration of 74.7% by weight, 1990 g of an aqueous sulfur source solution (including NaSH = 21.8 mol and Na ₂ S = 0.50 mol), and NMP 1000 g were added and gradually increased to 200 ° C. over about 2 hours. Then, 945 g of water, 1590 g of NMP, and 0.31 mol of hydrogen sulfide were discharged out of the system.

  After the dehydration step, the mixture was cooled to 170 ° C., 3283 g of p-dichlorobenzene, 2800 g of NMP, 133 g of water, and 23 g of NaOH having a concentration of 97% by weight were added, and the inside temperature of the can reached 130 ° C. Subsequently, while stirring at a rotational speed of 250 rpm of the stirrer, the temperature was raised to 180 ° C. over 30 minutes, and further between 180 ° C. and 220 ° C. over 60 minutes. After reacting at that temperature for 60 minutes, the temperature was raised to 230 ° C. over 30 minutes, and the reaction was carried out at 230 ° C. for 90 minutes to perform pre-stage polymerization.

  Immediately after completion of the pre-polymerization, the rotation speed of the stirrer was increased to 400 rpm, and 340 g of water was injected. After water injection, the temperature was raised to 260 ° C. over 1 hour, and the reaction was carried out at that temperature for 5 hours to carry out post polymerization.

After completion of the post-polymerization, the reaction mixture is cooled to near room temperature, the contents are passed through a 100 mesh screen, the particulate polymer is filtered off, then washed with acetone three times and with ion-exchanged water five times. A washed granular polymer was obtained. The granular polymer was dried at 105 ° C. for 13 hours. The granular polymer thus obtained had a melt viscosity (310 ° C., shear rate of 1200 sec ⁻¹ ) of 195 Pa · s and a crystallization temperature of 190 ° C.
(A'-2)
Kureha Co., Ltd., Fortron KPS; melt viscosity (310 ° C, shear rate 1200 sec ^-1 ) 20 Pa · s, crystallization temperature 234 ° C
(A'-3)
Kureha Co., Ltd., Fortron KPS; melt viscosity (310 ° C, shear rate 1200 sec ^-1 ) 135 Pa · s, crystallization temperature 231 ° C
・ (B) Inorganic filler
(B-1) Glass fiber (Asahi Glass Fiber Glass Co., Ltd., CS03JAFT636, average fiber diameter 10 μm, chopped strand)
(B-2) Glass beads (manufactured by Toshiba Ballotini Co., Ltd., EGB053Z-A)
(B-3) Calcium carbonate (Shiraishi Calcium Co., Ltd., Whiten P-30)
Moreover, the evaluation items and evaluation criteria in the examples are as follows.
[Measurement of resin crystallization temperature]
10 mg ± 1 mg was sampled and measured using DSC (DSC7 manufactured by PerkinElmer).
[Measurement of melt viscosity]
Measurement was performed in accordance with ISO11443. A 1 mmφ × 20 mmL / flat die was used as the capillary, and the melt viscosity at a barrel temperature of 310 ° C. and a shear rate of 1000 sec ⁻¹ was measured.
[Measurement of tensile strength]
A test piece (width 10 mm, thickness 4 mm) according to ISO3167 was molded and measured according to ISO527-1,2.
[Measurement of dimensional variation between shots]
Box-shaped test pieces (length 100 mm, width 80 mm, height 20 mm, thickness 1.5 mm) shown in FIGS. 1 and 2 are molded using an injection molding machine (holding pressure 60 MPa, mold temperature 150 ° C.), 10 samples About the distance of the location shown in FIG. 2, it measured using Mitutoyo Corporation FN704. Among them, the difference between the maximum dimension and the minimum dimension was calculated, and the largest value among them was taken as the value of dimensional variation between shots.
[Flatness]
Using Mitutoyo Corporation's FN704, the height of the bottom of the box-shaped test piece was measured at 16 locations for each sample, and a reference surface was created from the average of the heights of the 16 locations. The difference between the maximum height and the minimum height was calculated. It was measured in the same manner as 5 samples, and the average value of the calculated differences was defined as the flatness value.
Examples 1-5, Comparative Examples 1-7
In the formulation shown in Table 1, the component (A) is charged into a twin screw extruder with a cylinder temperature of 320 ° C, and the component (B) is added separately from the side feed part of the extruder, and the resin temperature is raised to 350 ° C in the extruder. And kneaded to prepare pellets of the resin composition.

  Next, a test piece was molded from the pellet and the above test was performed. The results are shown in Table 1.

It is a perspective view of the box-shaped test piece used in the Example. It is a figure which shows the measurement location in the measurement test of the dimensional variation between shots performed in the Example.

Claims (2)

(A) For a polyarylene sulfide resin having a resin temperature of 310 ° C., a melt viscosity at a shear rate of 1200 sec ⁻¹ of 10 to 100 Pa · s, and a crystallization temperature of 210 ° C. or less,
(B) An inorganic filler composed of a fibrous filler and a non-fibrous filler is blended in an amount of 40 to 70% by weight (in the composition), and (B) the proportion of the fibrous filler in the inorganic filler is 25 to 75. A polyarylene sulfide resin composition for molded articles having a box shape that is% by weight.   A molded article having a box shape formed by molding the polyarylene sulfide resin composition according to claim 1.

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