JP2012082334A - Thermoplastic polyester resin composition for foaming and foamed molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic polyester resin composition for foaming capable of easily increasing an expansion ratio in various foaming molding methods, having high rank appearance on a producing surface, and giving a low coefficient of linear expansion.SOLUTION: The thermoplastic polyester resin composition for foaming includes: 99-50 wt.% of a thermoplastic polyester resin (a); and 1-50 wt.% of a polyethylene resin (b) having density of 920-960 kg/mand melt tension (MS) of 50-150 mN as measured at 160°C.

Description

  The present invention relates to a thermoplastic polyester resin composition and a foam-molded article using the composition. The foam molded product obtained from the thermoplastic polyester resin composition of the present invention is excellent in dispersibility of bubbles and the beauty of the surface of the molded product, and is excellent in mechanical performance such as impact resistance and strength. By utilizing this, it can be used extremely effectively for various molded products including machine parts, daily necessities, miscellaneous goods, industrial parts, containers, and other various uses.

  In recent years, due to increasing awareness of environmental issues, polyethylene terephthalate bottles (hereinafter polyethylene terephthalate may be abbreviated as “PET”) have been recycled. This recycled PET can be used for stationery, toys, carpets, etc. It has been reused. The supply of recycled PET is expected to increase in the future. In the future, how to recycle and consume this recycled PET will become an important issue.

  Among them, recently, as one of the methods for reusing recycled PET, utilization as an extender for polyolefin resins such as polypropylene and polyethylene has been proposed. As one of the attempts, polyolefin resin is used for recycled PET. Blended alloys are being considered. And, when molding large molded products such as containers, racks, cases, etc. using this alloy, foam molding may be performed by adding a foaming agent in order to prevent sink marks and reduce the weight of the molded products. . However, generally, the melt tension of polyester resins such as PET is low, and foam molding using an alloy of a polyester resin and a polyolefin resin as described above often leads to uneven and large bubbles, As a result, problems such as a decrease in strength such as tensile strength and bending strength or impact resistance, and irregularities and swirl marks on the surface of the molded product are liable to occur.

  Furthermore, in general, the polarity of polyester resins such as PET and polyolefin resins are greatly different, and due to their low compatibility, impact resistance is reduced particularly when molded products are molded. The phenomenon tends to occur.

  An object of the present invention is to provide a thermoplastic polyester resin composition for obtaining a foamed molded article having excellent foam dispersibility and the beauty of the surface of the molded article and having a high expansion ratio, and foam molding obtained from the resin composition. Is to provide goods.

As a result of intensive studies to solve the above problems, the present inventors have found that a thermoplastic polyester resin composition in which a foaming agent is blended with a polyester resin and a polyolefin resin is used to foam. Based on these findings, we have found that foamed products with excellent dispersibility of bubbles and the beauty of the surface of the molded product and excellent mechanical performance such as impact resistance and strength can be obtained. Completed the invention.
That is, the present invention relates to a foaming thermoplastic polyester resin composition comprising 99 to 50% by weight of a thermoplastic polyester resin (a) and 1 to 50% by weight of a polyethylene resin (b). is there.

  The present invention will be described in detail below.

  The foaming thermoplastic polyester resin composition of the present invention comprises 99 to 50% by weight of the thermoplastic polyester resin (a) and 1 to 50% by weight of the polyethylene resin (b). Here, when the thermoplastic polyester resin (a) exceeds 99% by weight (that is, the polyethylene resin (b) is less than 1% by weight), the resulting thermoplastic polyester resin composition is subjected to foam molding. However, since the foaming gas cannot be sufficiently retained, a foamed molded article having a uniform cell structure cannot be obtained. On the other hand, when the thermoplastic polyester resin (a) is less than 50% by weight (that is, the polyethylene resin (b) exceeds 50% by weight), the resulting thermoplastic polyester resin composition is subjected to foam molding even if it is subjected to foam molding. Does not grow sufficiently, only a molded product having a low expansion ratio can be obtained, and heat resistance is poor.

  The thermoplastic polyester resin (a) constituting the thermoplastic polyester resin composition for foaming of the present invention can be used without any limitation as long as it belongs to the category of thermoplastic polyester resins. There may be a commercially available one.

  Examples of the thermoplastic polyester resin used in the present invention include polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polybutylene naphthalate resin, poly-1,4-cyclohexanedimethylene terephthalate resin. Examples include resins, polycaprolactone resins, p-hydroxybenzoic acid polyester resins, polyarylate resins, and the like.

  Among the above-described thermoplastic polyester resins, the thermoplastic polyester resin is excellent in impact resistance and strength, such as the thermoplastic polyester resin composition of the present invention and the foam molded product obtained therefrom. As the resin, it is preferable to use at least one of polyethylene terephthalate resin and polybutylene terephthalate resin, and it is particularly preferable to use polyethylene terephthalate resin (hereinafter sometimes abbreviated as “PET resin”). The PET resin preferably used in the polyolefin resin composition of the present invention mainly comprises a dicarboxylic acid unit mainly composed of a terephthalic acid unit and a diol unit mainly composed of an ethylene glycol unit. Mention may be made of polyethylene terephthalate (PET) consisting only of ethylene glycol units.

  The thermoplastic polyester-based resin used in the present invention has a dicarboxylic acid unit other than the dicarboxylic acid unit constituting the basic structure and / or the basic structure as necessary as long as it is 20 mol% or less based on the total structural units. It may have other diol units other than the diol unit constituting Examples of other dicarboxylic acid units that the thermoplastic polyester resin may contain include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene Aromatic dicarboxylic acids such as dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, sodium 5-sulfoisophthalate; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, dodecanedioic acid; 1,3-cyclohexanedicarboxylic acid And dicarboxylic acid units derived from acid, alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid; and ester-forming derivatives thereof (lower alkyl esters such as methyl ester and ethyl ester). . The thermoplastic polyester-based resin may have only one kind of the above-described dicarboxylic acid units, or may have two or more kinds.

  Examples of other diol units that may be contained in the thermoplastic polyester resin include 2 carbon atoms such as propylene glycol, 1,4-butanediol, neopentyl glycol, 2-methylpropanediol, and 1,5-pentanediol. Derived from alicyclic diols such as cyclohexanedimethanol and cyclohexanediol; polyalkylene glycols having a molecular weight of 6000 or less such as diethylene glycol, polyethylene glycol, poly-1,3-propylene glycol and polytetramethylene glycol Diol units may be mentioned. The thermoplastic polyester resin may have only one of the above diol units or may have two or more.

Furthermore, if the thermoplastic polyester-based resin is 1 mol% or less based on the total structural unit, it is derived from a tri- or higher functional monomer such as glycerin, trimethylolpropane, pentaerythritol, trimellitic acid, or pyromellitic acid. You may have a structural unit.
Although not limited, the thermoplastic polyester resin used in the present invention may be a recycled PET resin. In that case, the PET resin has an intrinsic viscosity in the range of 0.5 to 0.85 when measured in a mixed solvent of phenol / tetrachloroethane (weight ratio = 1/1), and glass. The crystallization temperature from the state is preferably in the range of 110 to 130 ° C.
As the thermoplastic polyester resin (a), various thermosetting resins and thermoplastic resins such as cyanate ester resins, polyimides, silicone resins, polyolefins, polyesters, polyamides, polyphenylenes are used without departing from the object of the present invention. Mix one or more of oxide, polycarbonate, polysulfone, polyetherimide, polyethersulfone, polyetherketone, polyetheretherketone, polyamideimide, polyamide elastomer, polyolefin elastomer, polyester elastomer, polyalkylene oxide, etc. Can be used.

  In addition, the thermoplastic polyester resin composition of the present invention includes an antioxidant, a thermal decomposition inhibitor, an ultraviolet absorber, a crystallization nucleating agent such as talc, a crystallization accelerator, a colorant, and a flame retardant as necessary. 1 type or 2 types or more of reinforcing agents such as glass fibers and surface treatment agents, fillers, mold release agents, plasticizers, antistatic agents, hydrolysis inhibitors, adhesion assistants, and pressure-sensitive adhesives. May be.

  The method for preparing the thermoplastic polyester resin composition of the present invention is not particularly limited. For example, various additives are added to the polyester resin and polyolefin resin as necessary, and then melt kneading together with other optional components. Can be manufactured. Melt kneading can be carried out using a kneader such as a single screw extruder, a twin screw extruder, a kneader, a Banbury mixer, etc., and the type of apparatus used and melt kneading conditions are not particularly limited, It is good to knead | mix for 1 to 30 minutes at the temperature of the range of about 180-330 degreeC.

  The polyethylene resin (b) constituting the thermoplastic polyester resin composition for foaming of the present invention may be any one as long as it belongs to the category called polyethylene resin, such as an ethylene homopolymer, a high pressure method. Examples include low density polyethylene, ethylene-α-olefin copolymers composed of repeating units derived from ethylene and repeating units derived from α-olefins having 3 to 8 carbon atoms, and among them, foam having particularly excellent heat resistance. An ethylene homopolymer composed of repeating units derived from ethylene, or ethylene composed of repeating units derived from ethylene and an α-olefin having 3 to 8 carbon atoms. It is preferable that it is -alpha-olefin copolymer. 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 thermoplastic polyester-type resin composition for foaming from which the foaming molding which has especially heat resistance and a high expansion ratio is obtained, (A) In accordance with JIS K6760. The density (d) measured by the density gradient tube method is 920 kg / m ³ or more and 960 kg / m ³ or less, and (B) the melt tension (MS ₁₆₀ ) measured at 160 ° C. is in the range of 50 to 150 mN. In addition, since a foamed molded article having excellent foam moldability when obtaining a foamed molded article and excellent mechanical strength and color tone can be obtained, (C) a melt flow rate measured at 190 ° C. with a 2.16 kg load (hereinafter referred to as “foam molded article”) MFR) 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, and (E) melting measured at 160 ° C. The relationship between tension (hereinafter referred to as MS ₁₆₀ ) and MFR satisfies the following formula (1), 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} )
As the polyethylene-based resin (b), since it becomes a melt tension improving agent that is particularly excellent in the effect of improving the melt tension when blended with the thermoplastic polyester-based resin, (H) weight average molecular weight / number average molecular weight (hereinafter, M _w / M _n .) 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 thermoplastic polyester 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. It is obtained by a method such as a low pressure polymerization method using a polymerization catalyst such as a catalyst, and satisfies the above (A) to (G) and (H). As a method for producing a polyethylene-based resin, for example, the production conditions of Examples of the present invention to be described later can be arbitrarily prepared by fine adjustment of 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-based resin constituting the thermoplastic polyester-based resin composition for foaming of the present invention, it is preferable to carry out at a polymerization temperature of −100 to 120 ° C., and in consideration of productivity, 20 to 120 ° C. is preferable. Furthermore, it is preferable to carry out 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 producing a foam molded article using the thermoplastic polyester resin composition of the present invention, it is generally used for a thermoplastic polyester polymer depending on the type, use, shape, etc. of the desired foam molded article. Various molding methods and molding apparatuses that have been used can be used. Although it is not limited at all, the thermoplastic polyester resin composition of the present invention is used, for example, by any molding method such as injection molding, extrusion molding, press molding, blow molding, calendar molding, casting molding, etc. Foam molded products can be produced, and molding can also be performed by a combination of these molding techniques. Furthermore, it can be molded by composite molding with other polymers. By these moldings, machine parts, daily necessities, miscellaneous goods, industrial parts, containers, parts for office equipment, stationery, toys, pipes, sheets, and other foam molded products of any shape and application can be manufactured. The invention includes within the scope of the present invention a foam-molded article produced by using the above-described thermoplastic polyester resin composition of the present invention.

  The foaming agent used when foaming the thermoplastic polyester resin composition for foaming of the present invention is not particularly limited. Examples of the thermally decomposable foaming compound include a pyrolytic foaming agent that decomposes to generate nitrogen gas. (Azodicarbonamide, azobisisobutyronitrile, dinitrosopentamethylenetetramine, p-toluenesulfonyl hydrazide, p, p'-oxy-bis (benzenesulfonyl hydrazide), etc.), thermal decomposition that decomposes to generate carbon dioxide Well-known pyrolyzable foaming compounds such as type inorganic foaming agents (sodium hydrogen carbonate, ammonium carbonate, ammonium hydrogen carbonate, etc.); gases such as carbon dioxide, butane, propane, etc.

  In addition, the foaming thermoplastic polyester resin composition of the present invention can be a foamable thermoplastic polyester resin composition containing the foaming agent.

  By using the foaming thermoplastic polyester resin composition 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 the foaming thermoplastic polyester resin composition and A foamed molded article can be provided.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereby. In the following examples and comparative examples, the preparation of test pieces, the measurement of impact resistance (unnotched IZOD impact value) and bending strength, and the evaluation of the dispersibility of bubbles and the beauty of the molded product surface are as follows. I went.

-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 nitrogen flow And kneaded for 30 minutes at 190 ° C. and 30 rpm.

-Preparation of test piece-
The pellets of the thermoplastic polyester resin composition obtained in the examples or comparative examples were used as molding materials, and a chemical foaming agent (ADCA: azodicarbonamide) was blended at a ratio of 1.0 part by weight. Using a 120-ton injection molding machine manufactured by Co., Ltd., foam molding is performed under conditions of a cylinder temperature of 265 ° C. and a mold temperature of 40 ° C., and a test piece for evaluating the dispersibility of bubbles and the beauty of the surface of the molded product (Dimensions: length × width × thickness = 147 mm × 97 mm × 6.2 mm) were prepared.

~ Foaming ratio ~
A 50 mm square sample is cut out from the foam produced by injection molding, the weight W2 (g) is measured, and the apparent density is calculated by the following formula in accordance with JIS K6767.

Apparent density (g / cm ³ ) = W2 / (5 × 5 × 0.62)
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 thermoplastic polyester resin composition for foaming and the state of bubbles in the cross section were visually evaluated.

Smooth surface, foam-shaped closed cells ... ○
Uneven foam shape, open cells ... ×
-Evaluation of dispersibility of bubbles-
The center part of the test piece produced above was cut out, the cross section was observed with an optical microscope, and the dispersibility of bubbles was evaluated as follows.

○: Bubbles of 0.05 to 0.3 mm are dispersed Δ: Bubbles of 0.3 to 1 mm are dispersed ×: Bubbles of 1 mm or more are dispersed ~ Evaluation of the beauty of the molded product surface ~
The surface of the test piece produced above was observed visually, and its beauty was evaluated as follows.

    ○: No swirl mark is generated.

    Δ: A swirl mark occurs on a part of the surface.

    X: Swirl marks are generated on the entire surface, and irregularities are also observed.

~ Closed cell ratio ~
Closed cell ratio: S (%) is the actual volume of the foam measured in accordance with Procedure C described in ASTM D2856-70 and using an air comparison type hydrometer 930 manufactured by Toshiba Beckman Co., Ltd. (Sum of the volume of closed cells and the volume of the resin portion): A value calculated from Vx (L) by the following formula.

S (%) = (Va−Vx) × 100 / (Va−W / ρ)
However, Va, W, and ρ in the above formula are as follows.

Va: Apparent volume (L) calculated from the outer dimensions of the foam specimen used for measurement
W: Weight of test piece (g)
ρ: Density of resin constituting the test piece (g / L)
The density ρ (g / L) of the resin constituting the test piece and the weight W (g) of the test piece are obtained by performing the operation of cooling the foam test piece after defoaming the bubbles with a heating press. It can be obtained from the test piece.

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 thermoplastic polyester resin composition for foaming]
The polyethylene resin obtained in Production Example 1 and a commercially available thermoplastic polyester pellet (trade name: polyethylene terephthalate (“KS750RCT” manufactured by Kuraray Co., Ltd.)) 20:80 (wt%) are dry blended, and this is blended. Using a twin screw extruder (trade name: TEM-35B-102B, manufactured by Toshiba Machine Co., Ltd.) having a screw diameter of 37 mmφ, the mixture was melt-kneaded at a cylinder temperature of 260 ° C. to be pelletized.

  The foaming ratio, foam shape, cell shape and the like of the foamed molded product of the thermoplastic polyester resin composition for foaming prepared by the injection molding method were evaluated. Table 1 shows the physical properties of the obtained thermoplastic polyester resin composition for foaming and the evaluation results of the foam.

Example 2
In Example 1, it carried out like 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.

  Since the thermoplastic polyester resin composition of the present invention is excellent in dispersibility of bubbles and the beauty of the surface of the molded product, taking advantage of these properties, it can be used for machine parts, daily necessities, miscellaneous goods, industrial parts, containers, and office equipment. It can be used very effectively for various molded articles including parts, stationery, toys, pipes, sheets, and other wide applications.

Claims (4)

It is composed of 99 to 50% by weight of a thermoplastic polyester resin (a) and 1 to 50% by weight of a polyethylene resin (b), and the polyethylene resin (b) satisfies the following (A) to (B). A thermoplastic polyester resin composition for foaming.
(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. The thermoplastic polyester resin composition for foaming according to claim 1, 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 thermoplastic polyester resin composition for foaming according to claim 1 or 2, wherein the polyethylene resin (b) further satisfies 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 foaming thermoplastic polyester resin composition according to any one of claims 1 to 3.