JP5215825B2 - Resin composition for foam molding of non-crosslinked mold and method for producing foam molded article of non-crosslinked mold - Google Patents

Description

The present invention relates to a manufacturing method of the non-cross-linked in the expanded bead molding resin composition and a non-cross-linked foamed articles.

Foam molded articles made of an ethylene-based resin such as linear low-density polyethylene and high-pressure method low-density polyethylene are excellent in flexibility and heat insulating properties, and thus are used in various applications as cushioning materials and heat insulating materials. As a method for producing a foamed molded body made of such an ethylene-based resin, an ethylene-based resin is previously foamed with butane gas to form foamed particles, filled in a mold, and a heating medium such as steam is introduced. So-called bead foam molding , in which heat fusion is performed, is known. Conventionally, in this bead foam molding, a foamed molded article having a high foaming ratio and excellent heat resistance can be easily obtained. Therefore, a crosslinked polyethylene has been used. However, a moldability is also obtained with a non-crosslinked ethylene-α-olefin copolymer. It has been proposed to produce a foam molded article with good quality (for example, Patent Document 1).

The in-mold foam-molded product can be produced by thermally fusing thermoplastic resin foam particles with each other in a mold. If the fusibility between the foamed particles is low, the product may be inferior in appearance or the product strength may not be sufficient. For this reason, a resin having high fusibility has been demanded, but the ethylene-α-olefin copolymer conventionally used in this field does not always satisfy the fusibility sufficiently.
JP 7-216153 A

Under such circumstances, an object of the present invention is to solve is made of a polyethylene-based resin excellent in heat resistance, and non-cross-linked in the expanded bead molding resin composition excellent in fusion bonding between the expanded beads and the composition and to provide a manufacturing method of the foamed molded article made from the object.

That is, the present invention consists of the following components (A) and (B), when the sum of the components (A) and (B) is 100 mass%, a component (A) is 90 to 60 wt% The resin composition for foam molding of non-crosslinking type beads , wherein the component (B) is 10 to 40% by mass.
(A) having a monomer unit based on ethylene and a monomer unit based on an α-olefin having 3 to 20 carbon atoms, a density of 900 to 940 kg / m ³ , and a melt flow rate (MFR) of 2 -5 g / 10 min, molecular weight distribution (Mw / Mn) measured by gel permeation chromatography (GPC) is 5 or more, and flow activation energy (Ea) is 40 kJ / mol or more An ethylene copolymer.
(B) An ethylene-α-olefin copolymer having a density of 941 to 970 kg / m ³ .

  Furthermore, the present invention provides foamed particles obtained by previously foaming the resin composition, filling the obtained foamed particles in a mold, and then heating to cause secondary foaming and fusion between the foamed particles. This is a method for producing a cross-linked in-mold foam molding.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a non-crosslinked type bead foam molding resin composition that is made of a polyethylene-based resin and that is capable of molding a foam molded article having excellent product particle appearance and excellent product appearance. Moreover, the manufacturing method of this invention is suitable for manufacture of the foaming molding of high expansion ratio.

  The ethylene-based copolymer that is the component (A) used in the present invention is an ethylene-α-olefin copolymer obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms. Examples of the α-olefin having 3 to 20 carbon atoms copolymerized with ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1 -Dodecene, 4-methyl-1-pentene, 4-methyl-1-hexene and the like. Among them, 1-butene, 1-hexene and 1-octene are preferable. These α-olefins may be used alone or in combination of two or more.

  Specific examples of the ethylene copolymer of component (A) include an ethylene-propylene copolymer, an ethylene-1-butene copolymer, an ethylene-1-hexene copolymer, and an ethylene-1-octene copolymer. And ethylene-1-butene-1-octene copolymer. Among them, an ethylene-1-butene copolymer, an ethylene-1-hexene copolymer, an ethylene-1-butene-1-hexene copolymer, and an ethylene-1-butene-1-octene copolymer.

  Content of the monomer unit based on ethylene in the ethylene-based copolymer of the component (A) is usually 50 to 99% by mass based on the total weight of the ethylene-based copolymer. The content of the monomer unit based on the α-olefin is usually 1 to 50% by mass based on the total weight of the ethylene copolymer.

  The ethylene-based copolymer of component (A) has a long chain branch, and compared with an ethylene-α-olefin copolymer for an in-mold foam molded body that has been conventionally used, a flow activation energy ( Ea) is usually as high as 40 kJ / mol or more. An ethylene-α-olefin copolymer that has been conventionally used for an in-mold foam molded article usually has an Ea lower than 40 kJ / mol.

  Ea of the ethylene-based copolymer of component (A) is preferably 45 kJ / mol or more, more preferably 50 kJ / mol or more, from the viewpoint of enhancing the uniformity of the bubble diameter in the obtained in-mold foam-molded product. Preferably it is 60 kJ / mol or more. Further, from the viewpoint of increasing the strength of the obtained in-mold foam molded article, the Ea is preferably 100 kJ / mol or less, more preferably 90 kJ / mol or less.

The Ea of the ethylene-based copolymer of component (A) is a shift factor (a _T when creating a master curve indicating the angular frequency dependence of the melt complex viscosity at 190 ° C. based on the temperature-time superposition principle. ) From the Arrhenius equation and is determined by the following method.

First, melt complex viscosity-angular frequency curves (units of melt complex viscosity: Pa · sec, units of angular frequency: rad / sec) of an ethylene copolymer are 130 ° C., 150 ° C., 170 ° C., 190 ° C. and 210 ° C. From the temperature of ° C., four temperatures including 190 ° C. (T, unit: ° C.) are created. Next, on the basis of the temperature-time superposition principle, each melt complex viscosity-angular frequency curve at each temperature (T) was superposed on the melt complex viscosity-angular frequency curve of the ethylene copolymer at 190 ° C. The shift factor (a _T ) at each temperature (T) obtained at this time is obtained. Furthermore, to prepare first-order approximation formula from a shift factor (a _T) by the least square method in the respective temperature (T) and the temperature (T) (Formula (I)), and calculates the slope m. By substituting the slope m of this linear approximation formula into the following formula (II), Ea is obtained.
ln (a _T ) = m {1 / (T + 273.16)} + n Formula (I)
Ea = | 0.008314 × m | Formula (II)
a _T : Shift factor Ea: Activation energy of flow (unit: kJ / mol)
T: Temperature (unit: ° C)

Note that the shift factor (a _T ) is obtained by moving the logarithmic curve of the melt complex viscosity-angular frequency at each temperature (T) and overlaying it on the melt complex viscosity-angular frequency curve (reference) at 190 ° C. It is the amount of movement at the time. In the superposition, the logarithmic curve of the melt complex viscosity-angular frequency at each temperature (T) moves the angular frequency by a _T times and the melt complex viscosity by 1 / a _T times.

In addition, the correlation coefficient when the linear approximation formula (I) obtained from the shift factor (a _T ) at four temperatures including 190 ° C. and the temperature (T) is obtained by the least square method is usually 0.99. That's it.

  For the calculation, commercially available calculation software may be used. The calculation software includes, for example, Rhios V. manufactured by Rheometrics. 4.4.4 (product name).

  The melt complex viscosity-angular frequency curve is measured using a viscoelasticity measuring device (for example, Rheometrics Mechanical Spectrometer RMS-800 (trade name) manufactured by Rheometrics), and usually geometry: parallel plate, plate diameter: 25 mm. Plate spacing: 1.5 to 2 mm, strain: 5%, angular frequency: 0.1 to 100 rad / sec. In addition, it is preferable to perform a measurement in nitrogen atmosphere and to mix | blend an appropriate quantity (for example, 1000 ppm) of antioxidant previously with a measurement sample.

The melt flow rate (MFR) of the ethylene copolymer of component (A) is 0.01 to 5 g / 10 min. The MFR is preferably 0.4 g / 10 min or more from the viewpoint of improving the lightweight property of the foamed molded product . Moreover, from the viewpoint of enhancing the uniformity of the cell diameter and the strength of the obtained foamed molded article, it is preferably 4 g / 10 min or less. In addition, MFR is measured on condition of load 21.18N and temperature 190 degreeC in the method prescribed | regulated to JISK7210-1999.

The density of the ethylene-based copolymer of the component (A) is preferably 940 kg / m ³ or less, more preferably 935 kg / m ³ or less, from the viewpoint of improving the lightweight property of the foamed molded product . From the viewpoint of reducing the stickiness of the foam molded article, preferably 900 kg / ^{m 3} or more, more preferably 905 kg / ^{m 3} or more. The density is measured according to the method A of the method defined in JIS K7112-1999.

The molecular weight distribution (Mw / Mn) of the ethylene copolymer of the component (A) is 5 or more. The molecular weight distribution is preferably 6 or more, more preferably 7 or more, from the viewpoint of enhancing the lightness of the foamed molded product . The molecular weight distribution is preferably 25 or less, more preferably 20 or less, and still more preferably 17 or less, from the viewpoint of increasing the strength of the foamed molded product . The molecular weight distribution (Mw / Mn) is determined by gel permeation chromatography (GPC) measurement to obtain a polystyrene-reduced weight average molecular weight (Mw) and number average molecular weight (Mn), and Mw is divided by Mn. Value (Mw / Mn).

  As a method for producing the ethylene-based copolymer of component (A), for example, a solid particulate formed by supporting a promoter component such as an organoaluminum compound, an organoaluminum oxy compound, a boron compound, an organozinc compound on a particulate carrier. A metallocene complex (hereinafter referred to as “cocatalyst component” (hereinafter referred to as “component (a)”) and a ligand having a structure in which two cyclopentadienyl type anion skeletons are bonded via a bridging group such as an alkylene group or a silylene group. , Referred to as component (b)) as a catalyst component, and a method of copolymerizing ethylene and α-olefin in the presence of a polymerization catalyst.

  Examples of the component (A) include a component in which methylalumoxane is mixed with porous silica, a component in which diethyl zinc, water, and fluorinated phenol are mixed with porous silica.

More specific examples of component (a) include component (a) diethylzinc, component (b) fluorinated phenol, component (c) water, component (d) porous silica and component (e) trimethyldisilazane ((( A carrier-supported cocatalyst obtained by contacting CH ₃ ) ₃ Si) ₂ NH) can be mentioned.

  As the fluorinated phenol of component (b), pentafluorophenol, 3,5-difluorophenol, 3,4,5-trifluorophenol, 2,4,6-trifluorophenol and the like can be used. From the viewpoint of increasing the fluid activation energy (Ea) and the molecular weight distribution (Mw / Mn) of the component (A), it is preferable to use two types of fluorinated phenols having different fluorine numbers. In this case, the number of fluorine atoms is large. The molar ratio of phenol to phenol with a small number of fluorine is usually 20/80 to 80/20, and a higher molar ratio is preferable.

When the molar ratio of the usage amounts of the components (a), (b) and (c) is 1: y: z, the usage amounts of these components preferably satisfy the following formula (III). .
| 2-y-2z | ≦ 1 Formula (III)

  Y in the above formula is preferably 0.01 to 1.99, more preferably 0.10 to 1.80, still more preferably 0.20 to 1.50, and most preferably 0.8. 30-1.00.

  The amount of component (d) used relative to component (a) is such that the number of moles of zinc atoms contained in the particles obtained by contact between component (a) and component (d) is 0.00 per gram of the particles. The amount is preferably 1 mmol or more, and more preferably 0.5 to 20 mmol. The amount of the component (e) to be used with respect to the component (d) is preferably an amount that makes the component (e) 0.1 mmol or more per 1 g of the component (d), and an amount that becomes 0.5 to 20 mmol. More preferably.

  As the component (b), a metallocene complex in which two indenyl groups are bonded by ethylene group, dimethylmethylene group or dimethylsilylene group, and a metallocene complex in which two methylindenyl groups are bonded by ethylene group, dimethylmethylene group or dimethylsilylene group Metallocene complex in which two methylcyclopentadienyl groups are bonded by ethylene group, dimethylmethylene group or dimethylsilylene group Metallocene complex in which two dimethylcyclopentadienyl groups are bonded by ethylene group, dimethylmethylene group or dimethylsilylene group Etc. The metal atom of component (b) is preferably zirconium and hafnium, and the remaining substituents of the metal atom are preferably a diphenoxy group or a dialkoxy group. The component (b) is preferably ethylenebis (1-indenyl) zirconium diphenoxide.

  In the polymerization catalyst comprising the above component (a) and component (b), an organoaluminum compound may be used in combination as a catalyst component as appropriate. Examples of the organoaluminum compound include triisobutylaluminum and trinormaloctyl. Aluminum or the like can be used.

The amount of the component (b) used is preferably 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ mol per 1 g of the component (b). The amount of the organoaluminum compound used is preferably such that the aluminum atom of the organoaluminum compound is 1 to 2000 mol per 1 mol of the metal atom of the component (b).

  In addition, in the polymerization catalyst using the component (a) and the component (b), an electron donating compound may be used in combination as a catalyst component as appropriate, and as the electron donating compound, triethylamine, trinormal or An octylamine etc. can be mentioned.

  When two types of fluorinated phenols having different numbers of fluorine are used as the component (b) fluorinated phenol, it is preferable to use an electron donating compound.

  The amount of the electron-donating compound used is usually 0.1 to 10 mol% with respect to the number of moles of aluminum atoms of the organoaluminum compound used as the catalyst component, and the molecular weight distribution (Mw / From the viewpoint of increasing Mn), it is preferable that the amount used is large.

  More specifically, as the method for producing the ethylene copolymer of component (A), a catalyst obtained by contacting a crosslinked bisindenylzirconium complex and an organoaluminum compound as component (a) and component (b) above In the presence of, a method of copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms may be mentioned.

  As the polymerization method, a continuous polymerization method involving molding of ethylene-based copolymer particles, for example, continuous gas phase polymerization, continuous slurry polymerization, and continuous bulk polymerization are preferable, and continuous gas phase polymerization is particularly preferable. The gas phase polymerization reaction apparatus is usually an apparatus having a fluidized bed type reaction tank, and preferably an apparatus having a fluidized bed type reaction tank having an enlarged portion. A stirring blade may be installed in the reaction vessel.

  As a method for supplying each component of the polymerization catalyst used for the production of the ethylene-based copolymer of component (A) to the reaction vessel, water is usually used using an inert gas such as nitrogen or argon, hydrogen, ethylene, or the like. And a method of supplying each component in a solution or slurry after dissolving or diluting each component in a solvent. Each component of the polymerization catalyst may be supplied individually, or arbitrary components may be supplied in contact in advance in any order.

  Moreover, it is preferable to carry out prepolymerization before carrying out the main polymerization and to use the prepolymerized prepolymerized catalyst component as a catalyst component or catalyst for the main polymerization. The main polymerization and the prepolymerization may have different α-olefin compositions, and it is preferable to prepolymerize the α-olefin having 4 to 12 carbon atoms with ethylene, and the α-olefin having 6 to 8 carbon atoms. It is more preferable to prepolymerize ethylene with ethylene.

  The polymerization temperature is usually lower than the temperature at which the ethylene copolymer melts, preferably 0 to 150 ° C, more preferably 30 to 100 ° C, and further preferably 50 to 90 ° C. From the viewpoint of expanding the molecular weight distribution (Mw / Mn) of the ethylene-α-olefin copolymer, a higher polymerization temperature is preferable.

  The polymerization time is usually 1 to 20 hours (as an average residence time in the case of a continuous polymerization reaction). From the viewpoint of expanding the molecular weight distribution (Mw / Mn) of the ethylene copolymer, it is preferable that the polymerization time (average residence time) is long.

  Further, for the purpose of adjusting the MFR of the copolymer, hydrogen may be added to the polymerization reaction gas as a molecular weight regulator, and an inert gas may be allowed to coexist in the polymerization reaction gas. The molar concentration of hydrogen in the polymerization reaction gas with respect to the molar concentration of ethylene in the polymerization reaction gas is usually 0.1 to 3 mol%, where the molar concentration of ethylene in the polymerization reaction gas is 100 mol%. Further, from the viewpoint of widening the molecular weight distribution (Mw / Mn) of the ethylene-based copolymer, it is preferable that the molar concentration of hydrogen in the polymerization reaction gas is higher.

The resin composition for non-crosslinking type internal bead foam molding of the present invention containing the component (A) and the component (B) may further contain other resins as required. Other resins include ethylene homopolymers such as high-density polyethylene, medium-density polyethylene, and low-density polyethylene, linear low-density polyethylene, and an ethylene-propylene copolymer containing more than 50% by mass of a structural unit derived from propylene, A copolymer that does not correspond to the ethylene-α-olefin copolymer can be used. In this invention, it is preferable that content of these other resin is 50 mass% or less normally with respect to a total of 100 mass% of a component (A) and a component (B).

The density of the ethylene-α-olefin copolymer of component (B) in the present invention is 941 to 970 kg / m ³ , preferably 945 to 965 kg / m ³ , and if it is less than 941 kg / m ³ , the heat resistance during in-mold foaming However , it is difficult to obtain a good appearance, and when it exceeds 970 kg / m ³ , the foamed molded article obtained has a high rigidity and cannot provide appropriate flexibility.

  The MFR of the ethylene-α-olefin copolymer of component (B) in the present invention is preferably 0.1 g / 10 min or more from the viewpoint of fluidity during molding, and 0.5 g / 10 min or more. More preferably. The MFR of the component (B) is preferably 50 g / 10 minutes or less, and more preferably 25 g / 10 minutes or less, from the viewpoint of impact strength of the foamed molded article to be obtained.

The compounding quantity of the component (A) in this invention is 95-60 mass% when the sum total of a component (A) and a component (B) is 100 mass%, Preferably it is 90-70 mass%. That is, the compounding quantity of a component (B) is 5-40 mass% with respect to the sum total of a component (A) and a component (B), Preferably it is 10-30 mass%. If the blending amount of the component (B) is less than 5% by mass, the heat resistance at the time of foaming in the mold is poor and it is difficult to obtain a good appearance, and if it exceeds 40% by mass , the foamability of the expanded particles is inferior. It becomes impossible to obtain pre-expanded particles exhibiting the expansion ratio.

  The components (A) and (B) are usually used after being melt-kneaded. Examples of the melt kneading method include a method in which the mixture is preliminarily mixed with a tumbler blender, a Henschel mixer, and the like, and is further melt kneaded with a single screw extruder or a multi screw extruder, or a melt kneading method with a kneader or a Banbury mixer. It is done. Or the method of supplying and melt-kneading component (B) from the middle of an extruder using a side feeder etc. in the case of extrusion of a component (A) with a single screw extruder or a multi-screw extruder is mentioned.

  The foaming agent used at the time of foaming particle manufacture is not specifically limited, A well-known physical foaming agent can be used. A plurality of foaming agents may be used in combination.

  Physical foaming agents include air, oxygen, nitrogen, carbon dioxide, ethane, propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, isohexane, cyclohexane, heptane, ethylene, propylene, water, petroleum ether, Examples include methyl chloride, ethyl chloride, monochlorotrifluoromethane, dichlorodifluoromethane, dichlorotetrafluoroethane and the like. The amount of the physical foaming agent used is usually 10 to 60 parts by mass with respect to 100 parts by mass of the resin composition.

  When a foaming agent is used, an extruded foam molded product having finer bubbles can be obtained by using a foam nucleating agent in combination. Foam nucleating agents include talc, silica, mica, zeolite, calcium carbonate, calcium silicate, magnesium carbonate, aluminum hydroxide, barium sulfate, aluminosilicate, clay, quartz powder, diatomaceous earth and other inorganic fillers; polymethyl methacrylate, Examples thereof include beads made of polystyrene and having a particle size of 100 μm or less; calcium stearate, magnesium stearate, zinc stearate, sodium benzoate, calcium benzoate, aluminum benzoate, magnesium oxide, etc. You may combine more than one type.

The resin composition for non-crosslinking type internal bead foam molding of the present invention containing the component (A) and the component (B) is, for example, calcium phosphate, aluminum oxide, titanium oxide, basic magnesium carbonate, basic zinc carbonate, etc. The dispersant may be contained.

The resin composition for non-crosslinking type internal bead foam molding of the present invention containing the component (A) and the component (B) is, if necessary, a heat stabilizer, a weather stabilizer, a pigment, a filler, a lubricant, an antistatic agent, You may contain well-known additives, such as a flame retardant and a neutralizing agent.

The foam of the present invention is produced by the following method. First, in the presence of a dispersant, a mini-pellet and a foaming agent obtained by adding a foam nucleating agent or an additive to the resin composition containing the component (A) and the component (B) in a pressure resistant container, After heating the mini-pellets dispersed in water close to their melting point and impregnating the foaming agent, the pressure in the pressure vessel is kept constant within the range of 20-50 kg / cm ² G above the vapor pressure indicated by the foaming agent. While the container contents are released under atmospheric pressure, expanded particles having an average particle diameter of 2 to 6 mm are obtained.

Immediately or after curing the foamed particles obtained by the above method over a long period of time under normal temperature and normal pressure, they are put into a mold and usually pressurized with water vapor under conditions of a water vapor pressure of 0.5 to 4 kg / cm ² . A foamed molded product can be produced. The foamed molded article obtained using the resin composition of the present invention usually has a high foaming ratio of 20 to 50 times.

The foamed molded article obtained by the present invention is excellent in the fusion property between the foamed particles and the appearance of the molded article is good. Therefore, it can be used as a buffer material, a heat insulating material, a sound insulating material, a heat insulating and cold insulating material, and the like.

  Hereinafter, the present invention will be described with reference to examples and comparative examples.

  The physical properties in Examples and Comparative Examples were measured according to the following methods.

(1) Melt flow rate (MFR, unit: g / 10 minutes)
In the method defined in JIS K7210-1995, the measurement was performed under the conditions of a load of 21.18 N and a temperature of 190 ° C.

(2) Density (Unit: kg / m ³ )
The density was measured according to the method A defined in JIS K7112-1999.

(3) Molecular weight distribution (Mw / Mn)
Measurement was performed under the following conditions using a gel permeation chromatograph (GPC) method. Weight average molecular weight (Mw) in terms of polystyrene, using a calibration curve prepared in advance using standard polystyrene (TSO STANDARD POLYSTYNE (trade name), manufactured by Tosoh Corporation) with a narrow molecular weight distribution that can be regarded as monodisperse. The number average molecular weight (Mn) in terms of polystyrene was determined, and the molecular weight distribution (Mw / Mn) was determined from them.
Apparatus: Waters 150C (trade name) manufactured by Waters
Separation column: TOSOH TSKgelGMH-HT (trade name)
Measurement temperature: 145 ° C
Carrier: Orthodichlorobenzene Flow rate: 1.0 mL / min Injection volume: 500 μL
Detector: Differential refraction

(4) Flow activation energy (Ea, unit: kJ / mol)
Using a viscoelasticity measuring device (Rheometrics Mechanical Spectrometer RMS-800 (trade name), manufactured by Rheometrics), measured melt complex viscosity-angular frequency curves at 130 ° C, 150 ° C, 170 ° C and 190 ° C under the following measurement conditions. Next, from the obtained melt complex viscosity-angular frequency curve, the calculation software Rhios V.R. The activation energy (Ea) of the flow was determined using 4.4.4 (trade name).
<Measurement conditions>
Geometry: Parallel plate Plate diameter: 25mm
Plate spacing: 1.2-2mm
Strain: 5%
Angular frequency: 0.1 to 100 rad / sec Measurement atmosphere: Under nitrogen

(5) Tensile properties The fusion strength of the pellets was determined by a tensile test as a substitute property for evaluating the fusion property between the expanded particles. Those having high fusion strength exhibit good fusion properties between the expanded particles. The pellets were arranged in a cylindrical shape having a length of about 3 mm and a cross-sectional area of about 9.5 mm ² . These pellets were arranged in a 5 mm thick × 10 mm × 70 mm spacer so as to form two layers. A test piece was prepared by pressure molding at 120 ° C. under conditions of preheating for 10 minutes, pressure for 10 minutes, and cooling for 5 minutes. The prepared test piece was subjected to a tensile test under the conditions of a distance between grips of 30 mm and a tensile speed of 10 mm / min to obtain a tensile fracture strength (unit: N) and a tensile fracture elongation (unit:%). The larger these values, the better the fusion property of the pellets.

(6) Melting peak temperature (Tm, unit: ° C)
The ethylene-α-olefin copolymer was pressed at a pressure of 10 MPa for 5 minutes with a 150 ° C. hot press machine, then cooled for 5 minutes with a 30 ° C. cooling press machine, and formed into a sheet having a thickness of about 100 μm. About 10 mg of sample was cut from the sheet and sealed in an aluminum pan. Next, the aluminum pan in which the sample was sealed was held at (1) 150 ° C. for 5 minutes with a differential scanning calorimeter (differential scanning calorimeter DSC-7 manufactured by Perkin Elmer), and (2) 5 ° C. (3) Hold at 20 ° C. for 2 minutes, (4) Increase the temperature from 20 ° C. to 150 ° C. at 5 ° C./minute, and calculate the melting curve in (4) It was measured. Of the peaks observed between 25 ° C and the melting end temperature (the temperature at which the melting curve returns to the high-temperature baseline) from the obtained melting curve, the temperature at the top of the melting peak observed on the highest temperature side Asked. In non-crosslinking type internal foaming, it can be said that a melting peak temperature of 120 ° C. or higher is preferable from the viewpoint of heat resistance.

The following materials were used in Reference Examples, Examples and Comparative Examples.
Component (A):
-Ethylene copolymer (PE-1 to 3): See the production examples described later.
Linear low-density polyethylene: <Sumikasen α> (trade name) grade FZ201-0, CS1009 and FZ103-0 manufactured by Sumitomo Chemical Co., Ltd., and <Sumikasen L> (trade name) grade FS240
Metallocene linear low-density polyethylene: Sumikasen E (trade name) grades FV203, FV205 and FV405 manufactured by Sumitomo Chemical Co., Ltd.
・ Plastomer: <affinity> (trade name) grade PF1140 manufactured by Dow Chemical
-Gas phase linear low density polyethylene: <Novatec LL> (trade name) grade UE320 manufactured by Nippon Polyethylene Corporation
Ingredient (B):
High-density polyethylene: <KEIYO polyethylene> (trade name) grade G1900 manufactured by Keiyo Polyethylene Co., Ltd. (ethylene-α-olefin copolymer, MFR = 15 g / 10 min, density = 956 kg / m ³ )

Production Example 1 (Production of ethylene copolymer (PE-1))
(1) Preparation of co-catalyst carrier (component (a)) Silica (Grace Devison, Sypolol 948 (trade name), heat-treated at 300 ° C. under nitrogen flow in a reactor equipped with a nitrogen-substituted stirrer; 50 % Volume average particle diameter = 59 μm; pore volume = 1.68 ml / g; specific surface area = 313 m ² / g) 0.36 kg and 3.5 liters of toluene were added, stirred, cooled to 5 ° C., A mixed solution of 0.15 liter of 1,1,3,3,3-hexamethyldisilazane and 0.2 liter of toluene was added dropwise over 30 minutes while maintaining the temperature in the reactor at 5 ° C. After completion of dropping, the mixture was further stirred at 5 ° C. for 1 hour, then heated to 95 ° C., stirred at 95 ° C. for 3 hours, and filtered. The obtained solid component was washed 6 times with 2 liters of toluene, and 2 liters of toluene was added to form a slurry, which was allowed to stand overnight.

The slurry obtained above was charged with 0.27 liters of diethylzinc in hexane (diethylzinc concentration: 2 mol / liter), stirred, cooled to 5 ° C., 0.05 kg of pentafluorophenol and 0. 09 liters of mixed solution was dripped over 60 minutes, keeping the temperature in a reactor at 5 degreeC. After completion of dropping, the mixture was further stirred at 5 ° C for 1 hour, then heated to 40 ° C, and stirred at 40 ° C for 1 hour. Then, after cooling to 5 ° C., 7 g of H ₂ O was added dropwise over 1.5 hours while maintaining the temperature in the reactor at 5 ° C. After completion of the dropwise addition, the mixture was stirred at 5 ° C. for 1.5 hours, then heated to 55 ° C., stirred at 55 ° C. for 2 hours, cooled to room temperature, and into it, hexane solution of diethyl zinc (diethyl zinc concentration) : 2 mol / liter) 0.63 liter was charged. After cooling again to 5 ° C., a mixed solution of 94 g of 3,4,5-trifluorophenol and 0.2 liter of toluene was added dropwise over 60 minutes while maintaining the temperature in the reactor at 5 ° C. After completion of dropping, the mixture was stirred at 5 ° C. for 1 hour, then heated to 40 ° C. and stirred at 40 ° C. for 1 hour. Then cooled to 5 ° C., was added dropwise for 1.5 hours while maintaining the H ₂ O 17 g The temperature of the reactor to 5 ° C.. After completion of dropping, the mixture was stirred at 5 ° C for 1.5 hours, then heated to 40 ° C, stirred at 40 ° C for 2 hours, further heated to 80 ° C, and stirred at 80 ° C for 2 hours.

  Then, the mixture is allowed to stand, and the solid component is allowed to settle. When the interface between the precipitated solid component layer and the upper slurry portion is visible, the upper slurry portion is removed, and then the remaining liquid components are removed with a filter. Then, 3 liters of toluene was added and stirred at 95 ° C. for 2 hours. Thereafter, the toluene-dispersed slurry was allowed to stand to settle the solid component, and when the interface between the precipitated solid component layer and the upper slurry portion was seen, the upper slurry portion was removed. The solid component was further washed four times with toluene, and then the same operation was performed twice with 3 liters of hexane at room temperature. Thereafter, the remaining liquid components were removed with a filter and dried at room temperature under reduced pressure for 1 hour to obtain a promoter support (component (a)) as a solid.

(2) Preparation of prepolymerization catalyst component (1) 80 liters of butane was charged into an autoclave with a stirrer having an internal volume of 210 liters that had been previously purged with nitrogen, and then 91.8 mmol of racemic-ethylenebis (1-indenyl) zirconium diphenoxide. The autoclave was heated to 50 ° C. and stirred for 2 hours. Next, after the temperature of the autoclave was lowered to 30 ° C. and the system was stabilized, 0.03 MPa of ethylene was charged at the gas phase pressure in the autoclave, and 0.7 kg of the promoter support (component (a)) was added. Then, 263 mmol of triisobutylaluminum was added to initiate polymerization. After 30 minutes while continuously supplying ethylene at 0.7 kg / Hr, the temperature was raised to 50 ° C., and ethylene and hydrogen were respectively 3.5 kg / Hr and 5.5 liters (room temperature and normal pressure volume) / Hr. A continuous polymerization was carried out for a total of 4 hours of prepolymerization. After completion of the polymerization, the remaining solids purged with ethylene, butane, hydrogen gas and the like are vacuum dried at room temperature to obtain a prepolymerized catalyst component (1) in which 23.8 g of polyethylene is prepolymerized per 1 g of the cocatalyst carrier. It was.

(3) Production of ethylene copolymer (PE-1) Using the prepolymerization catalyst component (1) obtained above, ethylene and 1-hexene were copolymerized in a continuous fluidized bed gas phase polymerization apparatus, A polymer powder was obtained. As polymerization conditions, the polymerization temperature was 87 ° C., the polymerization pressure was 2 MPa, the hydrogen molar ratio to ethylene was 0.63%, and the 1-hexene molar ratio to the total of ethylene and 1-hexene was 0.78%. During the polymerization, ethylene, 1-hexene and hydrogen were continuously supplied in order to keep the gas composition constant. Further, the prepolymerization catalyst component and triisobutylaluminum were continuously supplied, and the total powder weight of the fluidized bed was kept constant at 80 kg. The average polymerization time was 4 hours. Using the resulting polymer powder, an extruder (LCM50 (trade name) manufactured by Kobe Steel, Ltd.), feed rate 50 kg / hr, screw rotation speed 450 rpm, gate opening 50%, suction pressure 0.1 MPa, Granulation was carried out at a resin temperature of 200 to 230 ° C. to obtain an ethylene-1-hexene copolymer (PE-1).

Production Example 2 (Production of ethylene copolymer (PE-2))
33.8 g of polyethylene per 1 g of promoter support was prepolymerized in the same manner as in Production Example 1 (2) except that the amount of racemic-ethylenebis (1-indenyl) zirconium diphenoxide was 90.7 mmol. A preliminary polymerization catalyst component (2) was obtained.

  Using the prepolymerization catalyst component (2) obtained above, the polymerization temperature was 82 ° C., the polymerization pressure was 2 MPa, the hydrogen molar ratio to ethylene was 1.12%, and the 1-hexene molar ratio to the total of ethylene and 1-hexene was An ethylene-1-hexene copolymer (PE-2) was obtained in the same manner as in (3) of Production Example 1 except that the content was 1.2%.

Production Example 3 (Production of ethylene copolymer (PE-3))
The polymerization temperature was 84 ° C., the polymerization pressure was 2 MPa, the hydrogen molar ratio to ethylene was 1.69%, and the 1-hexene molar ratio to the total of ethylene and 1-hexene was 1.15%. In the same manner as (3), an ethylene-1-hexene copolymer (PE-3) was obtained.

  The physical properties of the obtained PE-1 to 3 were evaluated as described above. The evaluation results are shown in Table 1.

Reference Examples 1 and 2 and Example 1
As component (A), 80% by mass of PE-1 to 3 pellets obtained in the production example and 20% by mass of G1900 pellets as component (B) were mixed for 1 minute with a tumble mixer. This mixed raw material is supplied to a single screw extruder having a screw diameter of 30 mmφ and L / D = 25, under the conditions that the temperature of the kneading part is 190 to 210 ° C., the temperature of the die part is 210 ° C., and the discharge rate is about 5 kg / h. Extrusion was performed to obtain a cylindrical pellet having a length of about 3 mm and a cross-sectional area of about 9.5 mm ² . Using the obtained pellets, a test piece for evaluation of fusing property was prepared in accordance with the above (5) tensile properties, and a tensile test was performed. Moreover, according to said (6) melting | fusing point, the melting peak temperature was measured. The obtained physical properties are shown in Table 2.

Reference example 3
Pellets were prepared in the same manner as in Reference Example 1 except that the amounts of component (A) and component (B) used were 95% by mass / 5% by mass, respectively. (5) Tensile test and (6) Melting peak temperature Measurements were made. The results are shown in Table 2.

Comparative Examples 1 and 2
Pellets were prepared in the same manner as in Reference Example 1 except that the amounts of component (A) and component (B) used were 100% by mass / 0% by mass and 50% by mass / 50% by mass, respectively (5) Tensile test And (6) The melting peak temperature was measured. The results are shown in Table 2.

Comparative Examples 3-11
A pellet was prepared in the same manner as in Reference Example 1 except that the components shown in Table 2 were used instead of the component (A), and a tensile test and a measurement of a melting peak temperature were performed. The results are shown in Table 2.

Claims (2)

It consists of the following component (A) and component (B), and when the total of component (A) and component (B) is 100% by mass, component (A) is 90 to 60% by mass, and component (B) is A resin composition for foam molding of non-crosslinked mold beads, which is 10 to 40% by mass.
(A) having a monomer unit based on ethylene and a monomer unit based on an α-olefin having 3 to 20 carbon atoms, a density of 900 to 940 kg / m ³ , and a melt flow rate (MFR) of 2 -5 g / 10 min, molecular weight distribution (Mw / Mn) measured by gel permeation chromatography (GPC) is 5 or more, and flow activation energy (Ea) is 40 kJ / mol or more An ethylene copolymer.
(B) An ethylene-α-olefin copolymer having a density of 941 to 970 kg / m ³ .   The resin composition according to claim 1 is expanded in advance to obtain expanded particles, and the obtained expanded particles are filled in a mold and then heated to cause secondary expansion and fusion between the expanded particles. A method for producing an in-mold foam molding.