JP2012082299A - Polyphenylene sulfide-based resin composition for foaming and foam molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PPS-based resin composition for foaming whose expansion ratio can be easily increased in various foam molding processes, which also imparts a high-class feeling to the surface of a product and gives a low linear foaming coefficient, and to provide a foam molded article.SOLUTION: The PPS-based resin composition for foaming is composed of: 99 to 50 wt.% of a polyphenylene sulfide resin (a); and 1 to 50 wt.% of a polyethylene-based resin (b) which has a density of 920 to 960 kg/mand a melt tension (MS) in the range of 50 to 150 mN measured at 160°C.

Description

  The present invention relates to a foaming polyphenylene sulfide resin (hereinafter referred to as PPS resin) resin composition and a foamed molded article using the composition.

  PPS resin has high heat resistance and is excellent in moldability, mechanical properties, durability, and chemical resistance. Therefore, PPS resin is used in various applications such as automobile parts and electrical / electronic parts by utilizing these properties. Yes. In particular, in applications where conventional metals have been used, such as heat-resistant parts, PPS resin is preferably used for the purpose of weight reduction, and further weight reduction in combination with the universal design of home appliances and the improvement in fuel efficiency of automobiles The demand for is growing.

  Foam molding is known as a technique for reducing the weight of resin products, but general PPS resin has a low melt tension, and when high foam molding is performed, the gas pressure of the foaming agent destroys the molten resin film, which is coarse. Therefore, it was difficult to obtain a foam having a uniform cell structure.

  Therefore, the present invention provides a PPS resin composition for foaming and a foamed molded article that can easily increase the foaming ratio in various foam molding methods, have a high-grade feeling on the product surface, and give a low heat shrinkage rate. It is in.

  As a result of intensive studies to solve the above problems, the present inventor has found that a specific PPS resin composition composed of a PPS resin and a polyethylene resin is excellent in foam moldability, thereby completing the present invention. It was.

  That is, the present invention relates to a PPS resin composition for foaming, comprising 99 to 50% by weight of PPS resin (a) and 1 to 50% by weight of polyethylene resin (b).

  The present invention will be described in detail below.

  The PPS resin composition for foaming of the present invention comprises 99 to 50% by weight of PPS resin (a) and 1 to 50% by weight of polyethylene resin (b). Here, when the PPS resin (a) exceeds 99% by weight (that is, the polyethylene resin (b) is less than 1% by weight), even if the obtained PPS resin composition is subjected to foam molding, the foaming gas is used. Cannot be sufficiently retained, it is impossible to obtain a foamed molded article having a uniform cell structure. On the other hand, when the PPS resin (a) is less than 50% by weight (that is, the polyethylene resin (b) exceeds 50% by weight), even if the obtained PPS resin composition is subjected to foam molding, the bubbles can grow sufficiently. In addition, only a molded product having a low expansion ratio can be obtained, and the heat resistance is poor.

  The PPS resin (a) constituting the PPS resin composition for foaming of the present invention can be used without any limitation as long as it belongs to the category of PPS resin. For example, p-phenylene sulfide Examples thereof include homopolymers or copolymers composed of units, m-phenylene sulfide units, o-phenylene sulfide units, phenylene sulfide sulfone units, phenylene sulfide ketone units, phenylene sulfide ether units, and biphenylene sulfide units. Moreover, what is generally marketed may be used. In particular, since it becomes a foamed PPS resin composition that makes it possible to obtain a foamed molded article having a high foaming ratio, a measurement temperature of 315 is measured with a Koka flow tester equipped with a die having a diameter of 1 mm and a length of 2 mm. The melt viscosity measured under the conditions of 10 ° C. and a load of 10 kg is 70 to 15,000 poise, preferably 200 to 10,000 poise. If it is this range, the PPS-type composition obtained will be excellent in toughness and intensity | strength.

  The PPS resin (a) may contain an inorganic filler as necessary within the range that can be produced, and the inorganic filler is preferably glass fiber, calcium carbonate, and carbon fiber. Various other fibrous or non-fibrous fillers can also be used.

  Furthermore, as the PPS resin (a), various thermosetting resins and thermoplastic resins such as cyanate ester resins, polyimides, silicone resins, polyolefins, polyesters, polyamides, polyphenylene oxides are used without departing from the object of the present invention. , Polycarbonate, polysulfone, polyetherimide, polyethersulfone, polyetherketone, polyetheretherketone, polyamideimide, polyamide elastomer, polyolefin elastomer, polyester elastomer, polyalkylene oxide, etc. can do.

  The polyethylene resin (b) constituting the PPS resin composition for foaming of the present invention may be anything as long as it belongs to the category called polyethylene resin, such as ethylene homopolymer, high pressure method low density. Examples thereof include an ethylene-α-olefin copolymer composed of polyethylene, a repeating unit derived from ethylene and a repeating unit derived from an α-olefin having 3 to 8 carbon atoms, and among them, a PPS for foaming that is particularly excellent in heat resistance. Ethylene homopolymer composed of repeating units derived from ethylene or ethylene-α-olefin composed of repeating units derived from ethylene and an α-olefin having 3 to 8 carbon atoms A copolymer is preferred. Here, the repeating unit derived from an α-olefin having 3 to 8 carbon atoms is derived from an α-olefin having 3 to 8 carbon atoms, which is a monomer, and is contained in the ethylene-α-olefin copolymer. Examples of the α-olefin having 3 to 8 carbon atoms include propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, and 3-methyl-1-butene. . You may use together at least 2 types of these C3-C8 alpha olefins.

And as this polyethylene-type resin (b), since it becomes a PPS-type resin composition for foaming from which the foaming molding which has especially heat resistance and a high foaming ratio is obtained, it is a density gradient according to (A) JISK6760. Polyethylene resin having a density (d) measured by a tube method of 920 kg / m ³ or more and 960 kg / m ³ or less, and (B) a melt tension (MS ₁₆₀ ) measured at 160 ° C. in the range of 50 to 150 mN. It is. Furthermore, since it becomes a foaming PPS resin composition which is excellent in foam moldability when obtaining a foam molded article, and obtains a foam molded article excellent in mechanical strength and color tone, (C) at 190 ° C., 2.16 kg The melt flow rate (hereinafter referred to as MFR) measured with a load is 1 g / 10 min or more and 20 g / 10 min or less, and (D) the number of terminal vinyls is 0.2 or less per 1,000 carbon atoms, (E) The relationship between the melt tension measured at 160 ° C. (hereinafter referred to as MS ₁₆₀ ) and MFR satisfies the following formula (1), and preferably satisfies the following formula (2).
MS ₁₆₀ > 90-130 × log (MFR) (1)
MS ₁₆₀ > 110-130 × log (MFR) (2)
(F) The relationship between the melt tension measured at 190 ° C. (hereinafter referred to as MS ₁₉₀ ) and MS ₁₆₀ satisfies the following formula (3), and preferably satisfies the following formula (4).
MS ₁₆₀ / MS ₁₉₀ <1.8 (3)
MS ₁₆₀ / MS ₁₉₀ <1.7 (4)
(G) The flow activation energy (kJ / mol) (hereinafter referred to as _{E a.)} Polyethylene and relationship with the density, it satisfies the following formula (5), preferably satisfying the following formula (6) A resin is preferred.

_{125-0.105d <E a <88-0.0550d (5} )
_{127-0.107d <E a <88-0.060d (6} )
Since the polyethylene resin (b) is a melt tension improver that is particularly excellent in the effect of improving the melt tension when blended with the PPS resin, (H) weight average molecular weight / number average molecular weight (hereinafter referred to as M _w). / _Mn .) Is preferably 3 or more and 10 or less, more preferably 4 or more and 8 or less.

In addition, as a measuring method of the number of terminal vinyls in this invention, after heat-pressing a polyethylene-type resin, the film prepared by ice-cooling is 4000cm < ^-1 > -400cm < ^- > with a Fourier transform infrared spectrophotometer (FT-IR). It measured in the range of ¹ and computed by the following formula.
Number of terminal vinyls per 1000 carbon atoms (pieces / 1000 C) = a × A / L / d
(In the formula, a is an absorptivity coefficient, A is an absorbance of 909 cm ⁻¹ attributed to terminal vinyl, L is a film thickness, and d is a density. Note that a is 1000 carbons from ¹ H-NMR measurement. was determined from a calibration curve prepared using samples confirmed terminal number vinyl per atom. ^{1 H-NMR} measurement, NMR measurement apparatus (manufactured by JEOL Ltd., trade name GSX400) using deuterated benzene and o -In a mixed solvent of dichlorobenzene at 130 ° C. The number of terminal vinyls per 1000 carbon atoms was calculated from the integral ratio of the peak attributed to methylene and the peak attributed to terminal vinyl. (Based on methylsilane as a reference (0 ppm), a peak with a chemical shift of 1.3 ppm was assigned as methylene and a peak at 4.8 to 5.0 ppm was attributed to terminal vinyl.)
Moreover, MS ₁₆₀ in the present invention uses a die having a length of 8 mm and a diameter of 2.095 mm, an inflow angle of 90 °, a shear rate of 10.8 s ⁻¹ , a draw ratio of 47, and a measurement temperature of 160 ° C. When the maximum stretch ratio was less than 47, the value measured at the highest stretch ratio that did not break was designated as MS ₁₆₀ . Further, MS ₁₉₀ in the present invention was measured under the same conditions as MS ₁₆₀ except for the measurement temperature of 190 ° C.

E _a in the present invention can be obtained by performing dynamic viscoelasticity measurement in a temperature range of 160 ° C. to 230 ° C. and substituting the obtained shift factor into the Arrhenius equation.

M _w / M _n in the present invention is calculated by measuring a weight average molecular weight (M _w ) and a number average molecular weight (M _n ), which are standard polyethylene equivalent values, by gel permeation chromatography (GPC). Is possible.

  The polyethylene resin (b) constituting the PPS resin composition for foaming of the present invention is known as a method for producing a polyethylene resin, such as a high pressure polymerization method, a Ziegler-Natta catalyst, a chromium catalyst, a metallocene catalyst, etc. It may be obtained by a method such as a low pressure polymerization method using a polymerization catalyst, and is particularly preferably a polyethylene system satisfying the above (A) to (B), and further satisfying (C) to (G) and (H). As a method for producing the resin, for example, it is possible to arbitrarily make the production conditions themselves by finely adjusting the production conditions of the present embodiment described later or the condition factors.

  Specifically, for example, polymerization described in JP-A-2004-346304, JP-A-2005-248013, JP-A-2006-321991, JP-A-2007-169341, JP-A-2008-50278 In the presence of a catalyst, a method of polymerizing ethylene or a method of copolymerizing ethylene and an α-olefin having 3 to 8 carbon atoms can be used.

  More specifically, for example, as a metallocene compound, a bridged bis (substituted or unsubstituted cyclopentadienyl) zirconium complex in which two substituted or unsubstituted cyclopentadienyl groups are bridged by a crosslinking group (hereinafter referred to as component ( a) and a bridged (cyclopentadienyl) (fluorenyl) zirconium complex and / or a bridged (indenyl) (fluorenyl) zirconium complex (hereinafter referred to as component (b)). In the presence of, a method of polymerizing ethylene or a method of copolymerizing ethylene and an α-olefin having 3 to 8 carbon atoms can be used.

  Specific examples of component (a) include dimethylsilylene bis (cyclopentadienyl) zirconium dichloride, dimethylsilylene (cyclopentadienyl) (indenyl) zirconium, dichloride 1,1,3,3-tetramethyldisiloxane-1 , 3-diyl-bis (cyclopentadienyl) zirconium dichloride, 1,1-dimethyl-1-silaethane-1,2-diyl-bis (cyclopentadienyl) zirconium dichloride, propane-1,3-diyl-bis (Cyclopentadienyl) zirconium dichloride, butane-1,4-diyl-bis (cyclopentadienyl) zirconium dichloride, cis-2-butene-1,4-diyl-bis (cyclopentadienyl) zirconium dichloride, 1 , 1,2,2-Tetramethyl Disilane-1,2-diyl - dimethyl body bis (cyclopentadienyl) zirconium dichloride dichloride and the transition metal compound such as chloride, diethyl body, dihydro derivative, diphenyl body, can be exemplified dibenzyl body. Further, compounds in which the hydrogen of the cyclopentadienyl derivative of the above transition metal compound is substituted with a hydrocarbon group, and compounds in which the zirconium atom of the central metal is substituted with a titanium atom or a hafnium atom can also be exemplified.

  Specific examples of component (b) include diphenylmethylene (1-cyclopentadienyl) (9-fluorenyl) zirconium dichloride, diphenylmethylene (2-trimethylsilyl-1-cyclopentadienyl) (9-fluorenyl) zirconium dichloride, Diphenylmethylene (1-cyclopentadienyl) (2,7-dimethyl-9-fluorenyl) zirconium dichloride, diphenylmethylene (1-cyclopentadienyl) (2,7-di-t-butyl-9-fluorenyl) zirconium Dichloride, isopropylidene (1-cyclopentadienyl) (9-fluorenyl) zirconium dichloride, isopropylidene (1-cyclopentadienyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, diphenylsila Diyl (1-cyclopentadienyl) (9-fluorenyl) zirconium dichloride, dimethylsilanediyl (1-cyclopentadienyl) (9-fluorenyl) zirconium dichloride, diphenylmethylene (1-indenyl) (9-fluorenyl) zirconium dichloride Diphenylmethylene (2-phenyl-1-indenyl) (9-fluorenyl) zirconium dichloride, diphenylmethylene (2-phenyl-1-indenyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, etc. Examples thereof include dimethyl, diethyl, dihydro, diphenyl, and dibenzyl isomers of dichloride and the above transition metal compounds. Further, compounds in which the hydrogen of the cyclopentadienyl derivative of the above transition metal compound is substituted with a hydrocarbon group, and compounds in which the zirconium atom of the central metal is substituted with a titanium atom or a hafnium atom can also be exemplified.

  Moreover, the quantity of the component (b) with respect to a component (a) does not have a restriction | limiting in particular, It is preferable that it is 0.0001-100 times mole, Most preferably, it is 0.001-10 times mole.

  And as a metallocene catalyst using component (a) and component (b), for example, a catalyst comprising component (a), component (b) and an organoaluminum compound (hereinafter referred to as component (c)); a catalyst comprising a), component (b) and aluminoxane (hereinafter referred to as component (d)); a catalyst further comprising component (c); component (a), component (b) and protonic acid salt (Hereinafter referred to as component (e)), Lewis acid salt (hereinafter referred to as component (f)) or metal salt (hereinafter referred to as component (g)). Catalyst; catalyst further comprising component (c); catalyst comprising component (a), component (b), component (d) and inorganic oxide (hereinafter referred to as component (h)); component (a ), Component (b), component (h), component (e), component (f), component (g) A catalyst comprising at least one salt; a catalyst further comprising a component (c); a component (a), a component (b), a clay mineral (hereinafter referred to as component (i)), and a component (c). Catalysts: Catalysts comprising a component (a), a component (b), and a clay mineral treated with an organic compound (hereinafter referred to as component (j)) can be exemplified. Preferably, the component (a) and the component ( A catalyst comprising b) and component (j) can be used.

  Here, examples of the clay mineral that can be used as the component (i) and the component (j) include fine particles mainly composed of microcrystalline silicate. As a structural feature, a layered structure is formed, and various layers of negative charges are included in the layer. In this respect, it is greatly different from a metal oxide having a three-dimensional structure such as silica or alumina. These clay minerals are generally of a large layer charge, with pyrophyllite, kaolinite, dickite and talc groups (negative charge per chemical formula is approximately 0), smectite groups (negative charge per chemical formula is from about 0.25). 0.6), vermiculite group (negative charge per chemical formula is approximately 0.6 to 0.9), mica group (negative charge per chemical formula is approximately 1), brittle mica group (negative charge per chemical formula is approximately 2) It is classified. Each group shown here includes various clay minerals, and examples of the clay mineral belonging to the smectite group include montmorillonite, beidellite, saponite, hectorite and the like. Further, a plurality of the above clay minerals can be mixed and used.

  The organic compound treatment in component (j) refers to introducing an organic ion between clay mineral layers to form an ionic complex. Examples of the organic compound used in the organic compound treatment include N, N-dimethyl-n-octadecylamine hydrochloride, N, N-dimethyl-n-eicosylamine hydrochloride, N, N-dimethyl-n-docosylamine hydrochloride, N, N-dimethyloleylamine hydrochloride, N, N-dimethylbehenylamine hydrochloride, N-methyl-bis (n-octadecyl) amine hydrochloride, N-methyl-bis (n-eicosyl) amine hydrochloride, N-methyl -Dioleylamine hydrochloride, N-methyl-dibehenylamine hydrochloride, N, N-dimethylaniline hydrochloride can be exemplified.

  The catalyst comprising component (a), component (b) and component (j) can be obtained by bringing component (a), component (b) and component (j) into contact in an organic solvent, A method of adding component (b) to the contact product of (a) and component (j); a method of adding component (a) to the contact product of component (b) and component (j); and component (a) A method of adding the component (j) to the contact product of the component (b); a method of adding the contact product of the components (a) and (b) to the component (j) can be exemplified.

  As the contact solvent, aliphatic hydrocarbons such as butane, pentane, hexane, heptane, octane, nonane, decane, cyclopentane or cyclohexane, aromatic hydrocarbons such as benzene, toluene or xylene, ethyl ether or n-butyl ether And ethers such as halogenated hydrocarbons such as methylene chloride or chloroform, 1,4-dioxane, acetonitrile, or tetrahydrofuran.

  About a contact temperature, it is preferable to select between 0-200 degreeC and to process.

  The amount of each component used is 0.0001 to 100 mmol, preferably 0.001 to 10 mmol of component (a) per 1 g of component (j).

  The contact product of component (a), component (b) and component (j) prepared in this way may be used without washing, or may be used after washing. Further, when the component (a) or the component (b) is a dihalogen, it is preferable to further add the component (c). Further, component (c) can be added for the purpose of removing impurities in component (j), polymerization solvent and olefin.

  When producing the polyethylene resin constituting the PPS resin composition for foaming of the present invention, it is preferably carried out at a polymerization temperature of −100 to 120 ° C., particularly preferably 20 to 120 ° C. in consideration of productivity. Is preferably performed in the range of 60 to 120 ° C. The polymerization time is preferably in the range of 10 seconds to 20 hours, and the polymerization pressure is preferably in the range of normal pressure to 300 MPa. The polymerizable monomer is ethylene alone or ethylene and an α-olefin having 3 to 8 carbon atoms. When ethylene is an α-olefin having 3 to 8 carbon atoms, ethylene and α-olefin having 3 to 8 carbon atoms are used. As the olefin supply ratio, ethylene / C3-C8 α-olefin (molar ratio) of 1 to 200, preferably 3 to 100, and more preferably 5 to 50 can be used. It is also possible to adjust the molecular weight using hydrogen during polymerization. The polymerization can be carried out by any of batch, semi-continuous and continuous methods, and can be carried out in two or more stages by changing the polymerization conditions. In addition, the ethylene copolymer can be obtained by separating and recovering from the polymerization solvent by a conventionally known method after the completion of the polymerization and drying.

  Polymerization can be carried out in a slurry state, a solution state, or a gas phase state. In particular, when the polymerization is performed in a slurry state, an ethylene-based copolymer having a powder particle shape is efficiently and stably produced. Can do. Further, the solvent used for the polymerization may be any organic solvent that is generally used, and specific examples include benzene, toluene, xylene, propane, isobutane, pentane, hexane, heptane, cyclohexane, gasoline, and the like, propylene, Olefin itself such as 1-butene, 1-hexene and 1-octene can also be used as a solvent.

  In the PPS resin composition for foaming of the present invention, a stabilizer, a lubricant, a flame retardant, a dispersant, a filler, a cross-linking agent, an ultraviolet ray preventing agent, as necessary, without departing from the gist of the present invention. You may contain antioxidant, a coloring agent, etc.

  As a method for producing the PPS resin composition for foaming of the present invention, a method for preparing an ordinary resin composition can be used. For example, known methods such as extrusion kneading and roll kneading can be used as melting and mixing methods. And can be obtained by melt-kneading by this method.

  The foaming PPS resin composition of the present invention is a composition having excellent properties for various foam molding, for example, foam blow molding, extrusion foam molding, profile extrusion foam molding, and injection foam molding. Among them, particularly suitable as extrusion foaming.

  The foaming agent for foaming the PPS resin composition for foaming of the present invention is not particularly limited, and examples of the thermally decomposable foaming compound include a thermally decomposable foaming agent (azo) that decomposes to generate nitrogen gas. Dicarbonamide, azobisisobutyronitrile, dinitrosopentamethylenetetramine, p-toluenesulfonyl hydrazide, p, p'-oxy-bis (benzenesulfonyl hydrazide), etc.), pyrolytic inorganics that decompose to generate carbon dioxide Known pyrolytic foaming compounds such as foaming agents (sodium hydrogen carbonate, ammonium carbonate, ammonium hydrogen carbonate, etc.); gases such as carbon dioxide, butane, propane, and the like.

  Moreover, the PPS resin composition for foaming of the present invention can be a foamable PPS resin composition containing the foaming agent.

  By using the PPS resin composition for foaming of the present invention, the foaming ratio can be easily increased in various foam molding methods, and the product surface has a high-class feeling and gives a low linear expansion coefficient. Compositions and foamed molded articles can be provided.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these.

-Measurement of molecular weight and molecular weight distribution-
The weight average molecular weight (M _w ), number average molecular weight (M _n ), and ratio of the weight average molecular weight to the number average molecular weight (M _w / M _n ) of the polyethylene resin are measured by gel permeation chromatography (GPC). did. Tosoh Co., Ltd. HLC-8121GPC / HT is used as the GPC apparatus, Tosoh Co., Ltd. TSKgel GMHhr-H (20) HT is used as the column, the column temperature is set to 140 ° C., and 1 is used as the eluent. Measurement was performed using 2,4-trichlorobenzene. A measurement sample was prepared at a concentration of 1.0 mg / ml, and 0.3 ml was injected and measured. The calibration curve of molecular weight is calibrated using a polystyrene sample having a known molecular weight. In addition, _Mw and _Mn were calculated | required as a value of linear polyethylene conversion.

~ Measurement of density ~
The density (d) of the polyethylene resin was measured by a density gradient tube method in accordance with JIS K6760 (1995).

~ Calculation of flow activation energy ~
The activation energy (E _a ) of the flow of the polyethylene resin (b) is 150 ° C., 170 ° C., 190 using a disk-disk rheometer (manufactured by Anton Paar Co., Ltd., trade name: MCR-300). The shear storage elastic modulus G ′ and shear loss elastic modulus G ″ in the range of angular velocities of 0.1 to 100 rad / s are obtained at each temperature of ° C., the shift factor of the horizontal axis at the reference temperature of 150 ° C. is obtained, and the Arrhenius type formula Calculated by

~ Measurement of melt tension ~
The melt tension of polyethylene resin is set on a capillary viscometer (Toyo Seiki Seisakusho, trade name: Capillograph) with a barrel diameter of 9.55 mm and a die with a length of 8 mm, a diameter of 2.095 mm, and an inflow angle of 90 °. It was measured. In MS ₁₆₀ , the temperature was set to 160 ° C., the piston lowering speed was set to 10 mm / min, the stretch ratio was set to 47, and the load (mN) required for take-up was MS ₁₆₀ . When the maximum draw ratio was less than 47, the load (mN) required for taking up at the highest draw ratio that did not break was MS ₁₆₀ . The load (mN) measured by the same method with the temperature set at 190 ° C. was designated as MS ₁₉₀ .
Polyethylene resin (b) used for measurement of melt tension (MS ₁₆₀ , MS ₁₉₀ ) and flow activation energy (E _a ) was previously used as a heat-resistant stabilizer, Irganox 1010 ^™ (manufactured by Ciba Specialty Chemicals) 1 , 500 ppm, Irgaphos 168 ^TM (manufactured by Ciba Specialty Chemicals Co., Ltd.) with 1,500 ppm added, using an internal mixer (manufactured by Toyo Seiki Seisakusho Co., Ltd., trade name: Labo Plast Mill) under a nitrogen stream And kneaded for 30 minutes at 190 ° C. and 30 rpm.

~ Foaming ratio ~
A cylindrical foam having a diameter of 5 cm and a length of 10 cm was cut out from an extruded foam molded using the foamable PPS resin composition, and the weight W2 (g) was measured. According to JIS K6767, The apparent density is calculated by the following formula.

Apparent density (g / cm ³ ) = W2 / (2.5 × 2.5 × π × 10)
The expansion ratio was determined from the apparent density by the following formula.

Foaming ratio = 1 / apparent density-foam shape and bubble shape-
The appearance of the extruded foam formed using the PPS resin composition for foaming and the state of bubbles in the cross section were visually evaluated.

Smooth surface foam shape closed cells ... ○, uneven foam shape, open cells ... ×,
-Foam tear strength-
When an extruded foam molded using the PPS resin composition for foaming was torn by hand, a foam molded body that was not easily torn was indicated as ◯, and a foam molded body that was easily torn was denoted as x.

~ Heat shrinkage ~
A 15 mm x 15 mm square sample was cut out from an extruded foam molded using the PPS resin composition for foaming, and an orthogonal mark with a length of 10 mm each parallel to each side was written at the center. Was placed in a hot air circulating oven at 130 ° C., heated for 1 hour, taken out, and naturally cooled to room temperature. The length of each marked line of this heat-treated sample was measured, the average value was La (mm), and the heat shrinkage rate was calculated according to the following formula. Regarding heat resistance, those having a heat shrinkage of less than 5% in the thickness direction were regarded as acceptable.

Heat shrinkage rate (%) = [(10−La) / 10] × 100
The cooling temperature was 30 ° C.

Production Example 1
[Preparation of modified hectorite]
After adding 3 liters of ethanol and 100 ml of 37% concentrated hydrochloric acid to 3 liters of water, 585 g of N-methyldioleylamine (1.1 mol: product name: Armin M2O) was added to the resulting solution, A hydrochloride solution was prepared by heating to 60 ° C. 1 kg of hectorite was added to this solution. The suspension was stirred at 60 ° C. for 3 hours, and the supernatant was removed, followed by washing with 50 L of water at 60 ° C. Thereafter, 60 ° ^C., dried 10 -3 torr 24 hours, by grinding with a jet mill to obtain modified hectorite having an average particle diameter of 10.5 [mu] m.
[Preparation of production catalyst for polyethylene resin]
500 g of the modified hectorite was suspended in 3.3 liters of hexane, and 6.97 g (20.0 mmol) of dimethylsilanediylbis (cyclopentadienyl) zirconium dichloride and a hexane solution of triethylaluminum (1.18 M) 1.7. 1 liter (2 mol) was added and stirred at 60 ° C. for 3 hours. After allowing to stand and cooling to room temperature, the supernatant was taken out and washed twice with 4 liters of 1% triisobutylaluminum in hexane. The supernatant liquid after washing was extracted and made up to 5 liters with a 5% triisobutylaluminum hexane solution. Subsequently, 20% triisobutylaluminum was separately added to a suspension of diphenylmethylene (1-cyclopentadienyl) (2,7-di-tert-butyl-9-fluorenyl) zirconium dichloride (2.33 g, 3.48 mmol) in hexane (115 mL). A solution prepared by adding 79 ml of a hexane solution (0.71 M) was added and stirred at room temperature for 6 hours. The supernatant was removed by standing, washed twice with 4 liters of hexane, and hexane was added to finally obtain a catalyst slurry of 100 g / L.
[Manufacture of polyethylene resin]
In a polymerization vessel having an internal volume of 540 L, the hexane was 145 kg / hour, the ethylene was 33.0 kg / hour, the butene-1 was 1.0 kg / hour, the hydrogen was 19 NL / hour, and the polymer production amount was 30 kg / hour. The catalyst slurry prepared in [Preparation of Production Catalyst for Polyethylene Resin] was continuously supplied, and the polymerization reaction was continuously carried out while maintaining the total pressure at 3,000 kPa and the polymerization vessel internal temperature at 85 ° C. After continuously removing the slurry from the polymerization vessel and removing unreacted hydrogen, ethylene, and butene-1, a polyethylene resin powder was obtained through steps of separation and drying. Polyethylene resin pellets were obtained by melt-kneading and pelletizing the polyethylene resin powder using a 50 mm diameter single screw extruder set at 200 ° C. The density of the obtained polyethylene resin pellets was 950 kg / m ³ , and the MFR was 4.0 g / 10 min.

Production Example 2
Production Example 1 [Production of polyethylene resin] was performed in the same manner as in Production Example 1 except that the hydrogen supply amount was changed from 19 NL / hour to 12 NL / hour. The density of the obtained polyethylene resin was 950 kg / m ³ and the MFR was 2.0 g / 10 min.

Production Example 3
[Preparation of modified hectorite]
After adding 3 liters of ethanol and 100 ml of 37% concentrated hydrochloric acid to 3 liters of water, 330 g of N, N-dimethyl-octadecylamine (1.1 mol: manufactured by Lion Corporation, trade name: Armin DM18D) was added to the resulting solution. A hydrochloride solution was prepared by adding and heating to 60 ° C. To this solution, 1.0 kg of hectorite was added. The suspension was stirred at 60 ° C. for 3 hours, the supernatant was removed, and then washed with 5 L of water at 60 ° C. Thereafter, 60 ° ^C., dried 10 -3 torr 24 hours, by grinding with a jet mill to obtain modified hectorite having an average particle diameter of 10.5 [mu] m.
[Preparation of production catalyst for polyethylene resin]
500 g of the modified hectorite was suspended in 3.3 liters of hexane, and 6.97 g (20.0 mmol) of dimethylsilanediylbis (cyclopentadienyl) zirconium dichloride and a hexane solution of triethylaluminum (1.18 M) 1.7. 1 liter (2 mol) was added and stirred at 60 ° C. for 3 hours. After allowing to stand and cooling to room temperature, the supernatant was taken out and washed twice with 4 liters of 1% triisobutylaluminum in hexane. The supernatant liquid after washing was extracted and made up to 5 liters with a 5% triisobutylaluminum hexane solution. Subsequently, 20% triisobutylaluminum was separately added to a suspension of diphenylmethylene (1-cyclopentadienyl) (2,7-di-tert-butyl-9-fluorenyl) zirconium dichloride (2.33 g, 3.48 mmol) in hexane (115 mL). A solution prepared by adding 79 ml of a hexane solution (0.71 M) was added and stirred at room temperature for 6 hours. The supernatant was removed by standing, washed twice with 4 liters of hexane, and hexane was added to finally obtain a catalyst slurry of 100 g / L.
[Manufacture of polyethylene resin]
In the polymerization vessel having an internal volume of 540 L, the above-mentioned [145 kg / hour of hexane, 33.0 kg / hour of ethylene, 1.0 kg / hour of butene-1, 25 NL / hour of hydrogen and 30 kg / hour of polymer production] The catalyst slurry prepared in [Preparation of Production Catalyst for Polyethylene Resin] was continuously supplied, and the polymerization reaction was continuously carried out while maintaining the total pressure at 3,000 kPa and the polymerization vessel internal temperature at 85 ° C. After continuously removing the slurry from the polymerization vessel and removing unreacted hydrogen, ethylene, and butene-1, a polyethylene resin powder was obtained through steps of separation and drying. Polyethylene resin pellets were obtained by melt-kneading and pelletizing the polyethylene resin powder using a 50 mm diameter single screw extruder set at 200 ° C. The density of the obtained polyethylene resin pellets was 950 kg / m ³ , and the MFR was 6.0 g / 10 minutes.

Example 1
[Production of PPS resin composition for foaming]
Polyethylene resin obtained in Production Example 1 and commercially available PPS pellets (trade name: Sastil GS-40, manufactured by Tosoh Corporation, melt viscosity = 1,300 poise, density = 1,660 kg / m ³ ) 20:80 (weight) %) And using a twin screw extruder (trade name: TEM-35B-102B, manufactured by Toshiba Machine Co., Ltd.) with a screw diameter of 37 mmφ, it is melt-kneaded at a cylinder temperature of 300 ° C. and pelletized. did.
[Manufacture of Extruded Foam Molded Using PPS Resin Composition for Foaming]
A chemical foaming agent (ADCA: azodicarbonamide) was blended at a ratio of 1.0 part by weight to 100 parts by weight of the PPS resin composition for foaming. Then, using the extrusion equipment of a single screw extruder (screw diameter 50 mmφ, L / D = 28, manufactured by Chuo Kikai) set at 310 ° C., the PPS resin composition for foaming was supplied at 10 kg / hour, and rod-like foaming A shaped body was formed.

  About the foaming molding of the PPS resin composition for foaming created with the said manufacturing method, the foaming magnification, the foam shape, the bubble shape, tear strength, and the heat shrinkage rate were evaluated. Table 1 shows the physical properties of the obtained PPS resin composition for foaming and the evaluation results of the foam.

Example 2
In Example 1, it carried out similarly to Example 1 except having changed the compounding ratio of the polyethylene-type resin as shown in Table 1. The results are shown in Table 1.

Example 3
In Example 1, it carried out like Example 1 except having changed the polyethylene-type resin into the resin obtained by manufacture example 2. FIG. The results are shown in Table 1.

Example 4
In Example 1, it carried out similarly to Example 1 except having changed the polyethylene-type resin into the resin obtained by manufacture example 3. FIG. The results are shown in Table 1.

Comparative Example 1
Except for changing the polyethylene resin in Example 1 to low density polyethylene (LDPE) produced by a commercially available high pressure method (trade name: Petrocene 203, manufactured by Tosoh, MFR = 8 g / 10 min, density = 919 kg / m ³ ). Was carried out in the same manner as in Example 1.

  The results are shown in Table 1.

Comparative Example 2
In Example 1, the polyethylene-based resin was converted into a linear low-density polyethylene (trade name: Umerit 4540F, manufactured by Ube Industries, MFR = 3.9 g / 10 min, density = 944 kg / m ³ ) produced with a commercially available metallocene catalyst. The procedure was the same as in Example 1 except for the change.

  The results are shown in Table 1.

Comparative Example 3
The same operation as in Example 1 was performed except that the amount of the polyethylene resin added was 0.9% by weight in Example 1.

  The results are shown in Table 1.

Comparative Example 4
The same operation as in Example 1 was performed except that the addition amount of the polyethylene resin in Example 1 was changed to 52% by weight.

  The results are shown in Table 1.

  By providing a PPS resin composition for foaming and a foamed molded article that can easily increase the foaming ratio and have a high-quality feeling on the product surface and give a low linear expansion coefficient, Can be used.

Claims (5)

Polyphenylene sulfide resin (hereinafter referred to as PPS resin) (a) 99 to 50% by weight and polyethylene resin (b) 1 to 50% by weight. Polyethylene resin (b) includes the following (A) to (B): A foamed PPS resin composition characterized by satisfying
(A) The density (d) measured by the density gradient tube method in accordance with JIS K6760 is 920 kg / m ³ or more and 960 kg / m ³ or less.
(B) The melt tension (MS ₁₆₀ ) measured at 160 ° C. is in the range of 50 to 150 mN. PPS resin (a) is characterized by having a melt viscosity of 70 to 10000 poise measured with a Koka flow tester equipped with a die having a diameter of 1 mm and a length of 2 mm under a measurement temperature of 315 ° C. and a load of 10 kg. The PPS resin composition for foaming according to claim 1. 3. The foaming PPS resin composition according to claim 1 or 2, wherein the polyethylene resin (b) further satisfies the following (C) to (G).
(C) The melt flow rate (MFR) measured at 190 ° C. and a load of 2.16 kg is 1 g / 10 min or more and 20 g / 10 min or less.
(D) The number of terminal vinyls is 0.2 or less per 1,000 carbon atoms.
(E) The relationship between the melt tension (MS ₁₆₀ (mN)) measured at 160 ° C. and MFR satisfies the following formula (1).
MS ₁₆₀ > 90-130 × log (MFR) (1)
(F) The relationship between the melt tension (MS ₁₉₀ (mN)) measured at 190 ° C. and MS ₁₆₀ satisfies the following formula (2).
MS ₁₆₀ / MS ₁₉₀ <1.8 (2)
(G) The relationship between the flow activation energy (E _a (kJ / mol)) and the density satisfies the following formula (3).
_{125-0.105d <E a <88-0.055d (3} ) The PPS resin composition for foaming according to any one of claims 1 to 3, wherein the polyethylene resin (b) further comprises a polyethylene resin satisfying the following (H).
(H) The weight average molecular weight / number average molecular weight (M _w / M _n ) is 3 or more and 10 or less. A foamed molded article comprising the PPS resin composition for foaming according to any one of claims 1 to 4.