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WO2013031745A1 - Particules expansées de résine polyéthylène et articles moulés obtenus à partir de celles-ci - Google Patents

Particules expansées de résine polyéthylène et articles moulés obtenus à partir de celles-ci Download PDF

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Publication number
WO2013031745A1
WO2013031745A1 PCT/JP2012/071633 JP2012071633W WO2013031745A1 WO 2013031745 A1 WO2013031745 A1 WO 2013031745A1 JP 2012071633 W JP2012071633 W JP 2012071633W WO 2013031745 A1 WO2013031745 A1 WO 2013031745A1
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Prior art keywords
polyethylene resin
particles
expanded particles
polyethylene
resin
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Japanese (ja)
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清敬 中山
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Kaneka Corp
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Kaneka Corp
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/04—Homopolymers or copolymers of ethene
    • C08L23/08—Copolymers of ethene
    • C08L23/0807—Copolymers of ethene with unsaturated hydrocarbons only containing four or more carbon atoms
    • C08L23/0815—Copolymers of ethene with unsaturated hydrocarbons only containing four or more carbon atoms with aliphatic 1-olefins containing one carbon-to-carbon double bond
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0014—Use of organic additives
    • C08J9/0023—Use of organic additives containing oxygen
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0014—Use of organic additives
    • C08J9/0028—Use of organic additives containing nitrogen
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0061—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof characterized by the use of several polymeric components
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
    • C08J9/122—Hydrogen, oxygen, CO2, nitrogen or noble gases
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/16—Making expandable particles
    • C08J9/18—Making expandable particles by impregnating polymer particles with the blowing agent
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/22—After-treatment of expandable particles; Forming foamed products
    • C08J9/228—Forming foamed products
    • C08J9/232—Forming foamed products by sintering expandable particles
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/06—CO2, N2 or noble gases
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2205/00—Foams characterised by their properties
    • C08J2205/04—Foams characterised by their properties characterised by the foam pores
    • C08J2205/046—Unimodal pore distribution
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2205/00—Foams characterised by their properties
    • C08J2205/04—Foams characterised by their properties characterised by the foam pores
    • C08J2205/052—Closed cells, i.e. more than 50% of the pores are closed
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2323/04—Homopolymers or copolymers of ethene
    • C08J2323/08—Copolymers of ethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2471/00—Characterised by the use of polyethers obtained by reactions forming an ether link in the main chain; Derivatives of such polymers
    • C08J2471/02—Polyalkylene oxides
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/05—Alcohols; Metal alcoholates
    • C08K5/053—Polyhydroxylic alcohols
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/16—Nitrogen-containing compounds
    • C08K5/34—Heterocyclic compounds having nitrogen in the ring
    • C08K5/3467—Heterocyclic compounds having nitrogen in the ring having more than two nitrogen atoms in the ring
    • C08K5/3477—Six-membered rings
    • C08K5/3492—Triazines
    • C08K5/34922—Melamine; Derivatives thereof

Definitions

  • the present invention relates to polyethylene resin foamed particles and polyethylene resin foamed molded articles made of polyethylene resin foamed particles.
  • Polyethylene-based resin foamed molded articles are excellent in flexibility and heat insulation properties, and are therefore used in various applications as buffer packaging materials and heat insulating materials.
  • foamed particles obtained by foaming polyethylene resin particles with a foaming agent such as butane gas in advance (bead foaming) are filled in a mold, and a heat medium such as water vapor is introduced.
  • a foaming agent such as butane gas in advance
  • a heat medium such as water vapor
  • Patent Document 3 discloses linear low-density polyethylene pre-expanded particles copolymerized with 1-butene having a weight average molecular weight Mw / number average molecular weight Mn of 3 to 7, and molding with a smooth surface. Although the body was obtained, there was a problem that the range of vapor pressure that could be molded was narrow. When the technique disclosed in Patent Document 3 is followed, similar problems occur even when a comonomer having 6 or 8 carbon atoms is copolymerized.
  • Ultrazex 2022L is a linear low density polyethylene resin.
  • Ultrazex 2022L has a density of 0.920 g / cm 3 , a melt flow rate (hereinafter sometimes referred to as “MFR”) of 2.0 g / 10 minutes, and a molecular weight distribution Mw / Mn of 3.8. It is a copolymer with an ⁇ -olefin of formula 6.
  • MFR melt flow rate
  • the foamed particles tend to break and the open cell ratio tends to increase.
  • the average cell diameter of the polyethylene resin foamed particles is too small, there is a problem that the range of vapor pressure that can be molded is narrow, and when the open cell rate is high, the shrinkage of the in-mold foam molded product is remarkably usable. The problem remains that the molded body does not become a proper molded body.
  • a polyethylene resin is a mixture of an ethylene unit and an ⁇ -olefin unit having 3 to 20 carbon atoms, that is, a density of 900 to 940 kg / m 3 and a specific melt.
  • a method of using a mixture of a copolymer having a flow rate, a weight average molecular weight Mw / number average molecular weight Mn, fluid activation energy and a copolymer having a density of 941 to 970 kg / m 3 has also been proposed (Patent Literature). 8).
  • the present invention provides a polyethylene resin foam molded article having a wide range of vapor pressure that can provide a good molded article at the time of molding, a small dimensional shrinkage ratio to the mold after molding, and a beautiful surface. It is in providing a resin-based expanded resin particle.
  • the present inventor has obtained a linear low-density polyethylene-based resin having a specific density and a melt flow rate and having an Mw / Mn of 3 or more and less than 5.
  • the resulting non-crosslinked polyethylene resin foam molded article has a small shrinkage ratio against the mold.
  • the inventors have found that a molded article having a beautiful surface can be obtained, and have completed the present invention.
  • the present invention has the following configuration.
  • Polyethylene resin foamed particles obtained by foaming polyethylene resin particles using a linear low density polyethylene resin satisfying the following conditions (a) to (d) as a base resin, A polyethylene-based resin expanded particle having an average cell diameter of 200 ⁇ m or more and 700 ⁇ m or less and an open cell ratio of 12% or less.
  • the linear low density polyethylene resin is a copolymer of ethylene and an ⁇ -olefin having 6 and / or 8 carbon atoms.
  • the density is 0.920 g / cm 3 or more and less than 0.940 g / cm 3 .
  • the melt flow rate (MFR) is 0.1 g / 10 min or more and 5.0 g / 10 min or less.
  • MFR melt flow rate
  • Mw / Mn molecular weight distribution measured by gel permeation chromatograph (GPC) is 3 or more and less than 5.
  • GPC gel permeation chromatograph
  • the base resin contains 0.01 to 10 parts by weight of a hydrophilic compound with respect to 100 parts by weight of the linear low-density polyethylene resin.
  • Polyethylene resin foam obtained by filling the polyethylene resin foamed particles according to any one of [1] to [6] into a mold and then performing in-mold foam molding Molded body.
  • the first-stage expanded particles are placed in a pressurized tank, and air is introduced into the first-stage expanded particles by pressurizing with an inorganic gas to increase the internal pressure of the expanded particles from atmospheric pressure, and then the first-stage expanded particles are heated with water vapor.
  • the A method for producing expanded polyethylene resin particles having an average cell diameter of 200 ⁇ m or more and 700 ⁇ m or less and an open cell ratio of 12% or less.
  • the linear low-density polyethylene-based resin is a copolymer of ethylene and an ⁇ -olefin having 6 and / or 8 carbon atoms.
  • the density is 0.920 g / cm 3 or more and less than 0.940 g / cm 3 .
  • the melt flow rate (MFR) is 0.1 g / 10 min or more and 5.0 g / 10 min or less.
  • MFR melt flow rate
  • Mw / Mn measured by gel permeation chromatograph (GPC) is 3 or more and less than 5.
  • polyethylene resin foamed particles of the present invention it is easy to obtain a polyethylene resin foam molded article having a wide vapor pressure range, a small mold dimensional shrinkage, and a beautiful surface. Obtainable.
  • the polyethylene-based resin expanded particles of the present invention are obtained by expanding polyethylene-based resin particles having a linear low-density polyethylene-based resin that satisfies the following conditions (a) to (d) as a base resin. Expanded particles, Polyethylene resin foamed particles having an average cell diameter of 200 ⁇ m or more and 700 ⁇ m or less and an open cell ratio of 12% or less.
  • the linear low density polyethylene resin is a copolymer of ethylene and an ⁇ -olefin having 6 and / or 8 carbon atoms.
  • the density is 0.920 g / cm 3 or more and less than 0.940 g / cm 3 .
  • the melt flow rate (MFR) is 0.1 g / 10 min or more and 5.0 g / 10 min or less.
  • MFR melt flow rate
  • Mn molecular weight distribution measured by gel permeation chromatograph
  • the linear low density polyethylene resin used in the present invention is a copolymer of ethylene and an ⁇ -olefin having 6 and / or 8 carbon atoms.
  • the ⁇ -olefin having 6 and / or 8 carbon atoms include 1-hexene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, and 1-octene. Both ⁇ -olefins having 6 and 8 carbon atoms may be copolymerized.
  • a linear low density polyethylene resin copolymerized with an ⁇ -olefin having 6 carbon atoms and a linear low density polyethylene resin copolymerized with an ⁇ -olefin having 8 carbon atoms are mixed and used. Also good.
  • the ⁇ -olefin is preferably an ⁇ -olefin having 6 carbon atoms and more preferably 4-methyl-1-pentene from the viewpoint of easily obtaining a linear low density polyethylene resin having a density described later.
  • the content of these ⁇ -olefins in 100% by weight of the linear low density polyethylene resin is preferably 1% by weight or more and 20% by weight or less, particularly preferably 3% by weight or more and 10% by weight or less.
  • the ⁇ -olefin content is less than 1% by weight, the steam pressure range during molding tends to be narrow, and when it exceeds 20% by weight, the strength tends to decrease due to bending or compression.
  • the density of the linear low-density polyethylene resin used in the present invention is preferably 0.920 g / cm 3 or more and less than 0.940 g / cm 3 .
  • the density of the linear low density polyethylene resin is less than 0.920 g / cm 3 , the shrinkage of the polyethylene resin foamed molded product tends to increase, and when it is 0.940 g / cm 3 or more, the foamable temperature range is high. There is a tendency to narrow.
  • the density of the linear low density polyethylene resin in the present invention is preferably 0.920 g / cm 3 or more and less than 0.940 g / cm 3 , but the density of the polyethylene resin particles is 0.920 g / cm 3 or more. If the density is less than 0.940 g / cm 3, polyethylene resins having different densities may be mixed, and low-density polyethylene (LDPE) or high-density polyethylene (HDPE) is added to the linear low-density polyethylene resin. It can also be used by mixing. However, LDPE and / or HDPE can be mixed within a range in which the bubble diameter uniformity of the polyethylene resin expanded particles is not impaired. Specifically, in 100% by weight of the polyethylene resin particles, LDPE and / or HDPE. The content of is preferably 10% by weight or less, and more preferably 5% by weight or less.
  • the melt flow rate (MFR) of the linear low density polyethylene resin used in the present invention is preferably 0.1 g / 10 min or more and 5.0 g / 10 min or less, and 1.0 g / 10 min or more 3 More preferably, it is 0.0 g / 10 min or less. If the MFR of the linear low-density polyethylene resin is less than 0.1 g / 10 minutes, the expansion ratio of the obtained expanded particles tends to be too low, and if it exceeds 5.0 g / 10 minutes, the resulting expanded particles are formed. There is a tendency for the bubbles to be formed to be easily connected.
  • the MFR of the linear low-density polyethylene resin is a value measured under conditions of a temperature of 190 ° C. and a load of 2.16 kgf.
  • the molecular weight distribution (Mw / Mn) measured using a gel permeation chromatograph (hereinafter sometimes referred to as “GPC”) of a linear low density polyethylene resin is adjusted.
  • GPC gel permeation chromatograph
  • the molecular weight distribution (Mw / Mn) measured using the gel permeation chromatograph (GPC) of the linear low density polyethylene resin used in the present invention is preferably 3 or more and less than 5, and preferably 3 or more and 4 or less. Is more preferable.
  • Mw / Mn of the linear low-density polyethylene resin is less than 3, the moldable temperature range tends to be narrowed, and when the Mw / Mn is 5 or more, the dimensional shrinkage ratio of the molded product against the mold increases. There is a tendency that the beauty of the surface of the molded body is inferior.
  • the molecular weight distribution (Mw / Mn) is a value obtained by dividing Mw by Mn in polystyrene-equivalent weight average molecular weight Mw and number average molecular weight Mn obtained by gel permeation chromatography (GPC) measurement. .
  • a linear low-density polyethylene resin having a specific density, MFR and molecular weight distribution which is a copolymer of ethylene and an ⁇ -olefin having 6 and / or 8 carbon atoms as described above, is commercially available. Is possible.
  • Japanese Patent Application Laid-Open No. 2001-219517 describes Ultzex 2022L and 3520L, and these are copolymers of ethylene and an ⁇ -olefin having 6 carbon atoms. It is clear from Prime Polymer Co., Ltd./Product Catalog (issued in October 2010).
  • JP-A-9-095545, WO00 / 078828, JP-A-2006-307139, JP-A-2009-197226 and the like describe polymerization methods including catalyst technology for various linear low-density polyethylene resins. Based on these information, it is possible to obtain a prototype other than a commercial product by inquiring a polyethylene resin manufacturer.
  • the base resin in the present invention it is preferable to use a base resin containing 0.01 to 10 parts by weight of a hydrophilic compound with respect to 100 parts by weight of a linear low density polyethylene resin.
  • the hydrophilic compound is a compound containing a hydrophilic group such as a carboxyl group, a hydroxyl group, an amino group, an amide group, an ester group, a sulfo group, or a polyoxyethylene group in the molecule or a derivative thereof.
  • a hydrophilic group such as a carboxyl group, a hydroxyl group, an amino group, an amide group, an ester group, a sulfo group, or a polyoxyethylene group in the molecule or a derivative thereof.
  • examples of the compound containing a carboxyl group include lauric acid and sodium laurate
  • examples of the compound containing a hydroxyl group include ethylene glycol and glycerin.
  • Other hydrophilic organic compounds include organic compounds having a triazine ring such as melamine (chemical name: 1,3,5-triazine-2,4,6-triamine), isocyanuric acid, and isocyanuric acid condensate. Can be mentioned
  • the hydrophilic polymer is a polymer having a water absorption rate of 0.5% by weight or more measured in accordance with ASTM D570, so-called a hygroscopic polymer; from several times its own weight without being dissolved in water. It includes a water-absorbing polymer that absorbs water several hundred times and is difficult to dehydrate even under pressure; and a water-soluble polymer that dissolves in water at room temperature to high temperature.
  • hydrophilic polymer used in the present invention for example, Neutralize carboxylic acid groups of ethylene-acrylic acid-maleic anhydride terpolymer and ethylene- (meth) acrylic acid copolymer with alkali metal ions such as sodium ion and potassium ion and transition metal ions such as zinc ion An ionomer resin in which the molecules are cross-linked; Carboxyl group-containing polymers such as ethylene- (meth) acrylic acid copolymers; Polyamides such as nylon-6, nylon-6,6, copolymer nylon; Nonionic water-absorbing polymers such as polyethylene glycol; Polyether-polyolefin resin block copolymer represented by perestat (trade name, manufactured by Sanyo Kasei Co., Ltd.); Cross-linked polyethylene oxide polymers represented by Aqua Coke (trade name, manufactured by Sumitomo Seika Co., Ltd.) and the like. These may be used alone or in combination of two or more.
  • hydrophilic polymers hydrophilic monomers, nonionic water-absorbing polymers, and polyether-polyolefin resin block copolymers have relatively good dispersion stability in a pressure resistant container, and a relatively small amount. Addition is preferable because it exhibits water absorption. Furthermore, glycerin, polyethylene glycol, and melamine are preferable because the effects of the present invention are great.
  • the polyethylene resin particles of the present invention contain a cell nucleating agent (talc, calcium carbonate, zinc borate, kaolin, silica, etc.), an antioxidant, an antistatic agent, a colorant, a flame retardant and the like. It can be included.
  • a cell nucleating agent talc, calcium carbonate, zinc borate, kaolin, silica, etc.
  • an antioxidant an antistatic agent, a colorant, a flame retardant and the like. It can be included.
  • the polyethylene resin particles used in the present invention can be produced as follows.
  • a linear low density polyethylene resin is mixed with the hydrophilic compound and other additives by a mixing method such as a dry blend method or a master batch method.
  • the obtained mixture is melt-kneaded using an extruder, kneader, Banbury mixer (registered trademark), roll or the like, and the weight of one grain is preferably 0.2 to 10 mg, more preferably 0.5 to 6 mg.
  • the liquid hydrophilic compound may be directly added to the extruder and melt-kneaded.
  • the polyethylene resin expanded particles in the present invention can be produced as follows. For example, polyethylene resin particles are introduced into a pressure vessel together with water, a foaming agent, and a dispersant, and the pressure vessel is maintained at a predetermined temperature and pressure, and then the polyethylene resin particles are placed in a low-pressure atmosphere from the pressure vessel. It can be released and manufactured.
  • the foaming process may be referred to as “one-stage foaming”.
  • the polyethylene resin expanded particles obtained by single-stage expansion may be referred to as “single-stage expanded particles”.
  • the pressure vessel used in the present invention is not particularly limited as long as it can withstand the pressure in the vessel and the temperature in the vessel at the time of producing the polyethylene resin expanded particles, and examples thereof include an autoclave type pressure vessel.
  • the polyethylene-based resin expanded particles of the present invention in order to improve the dispersibility of the polyethylene-based resin particles in water, 100 parts by weight or more and 500 parts by weight of water with respect to 100 parts by weight of the polyethylene-based resin particles. It is preferable to use up to parts by weight.
  • the dispersant used in the present invention it is preferable to use a poorly water-soluble inorganic compound.
  • the poorly water-soluble inorganic compound refers to an inorganic compound having a water solubility at 25 ° C. of less than 1% by weight.
  • Specific examples of the hardly water-soluble inorganic compound include, for example, Alkaline earth metal salts such as calcium carbonate, barium carbonate, tricalcium phosphate, dicalcium phosphate, tribasic magnesium phosphate, tertiary barium phosphate, barium sulfate, calcium pyrophosphate; aluminosilicates such as kaolin and clay; Can be mentioned. These may be used alone or in combination of two or more.
  • the amount of the dispersant used in the present invention varies depending on the type and the type and amount of the polyethylene resin particles to be used, and cannot be generally specified, but is 0.2 to 5 parts by weight with respect to 100 parts by weight of the polyethylene resin particles.
  • the amount is preferably not more than parts by weight, more preferably not less than 0.2 parts by weight and not more than 3.0 parts by weight.
  • a dispersion aid may be used in combination with the dispersant.
  • a surfactant is preferably used, and an anionic surfactant, a nonionic surfactant, an amphoteric surfactant, an anionic polymer surfactant, and a nonionic polymer.
  • Surfactants such as surfactants are listed.
  • the anionic surfactant include sodium dodecylbenzene sulfonate, sodium n-paraffin sulfonate, sodium ⁇ -olefin sulfonate, sodium alkyldiphenyl ether sulfonate, and the like.
  • nonionic surfactants include polyoxyethylene alkyl ethers and polyoxyethylene sorbitan fatty acid esters.
  • amphoteric surfactants include alkyl betaines and alkyl amine oxides.
  • anionic polymer surfactant include polyacrylate, polystyrene sulfonate, maleic acid ⁇ -olefin copolymer salt and the like.
  • nonionic polymer surfactants include polyvinyl alcohol. These may be used alone or in combination of two or more.
  • the preferred dispersion aid type in the present invention varies depending on the type of dispersant used, it cannot be defined unconditionally.
  • an anionic surfactant is used. Is preferable because the dispersion state becomes stable.
  • the amount of the dispersion aid used in the present invention varies depending on the type and the type and amount of the polyethylene resin particles to be used, and cannot be generally defined, but is usually 0.001 weight per 100 parts by weight of water. It is preferable that the amount is not less than 0.2 parts by weight.
  • blowing agent used in the present invention examples include readily volatile hydrocarbons such as butane, pentane, and chlorofluorocarbon; inorganic gases such as nitrogen, carbon dioxide, and air; and water.
  • inorganic gases such as nitrogen, carbon dioxide, and air
  • water it is preferable to use an inorganic gas, and more preferable to use a foaming agent containing carbon dioxide gas, from the viewpoint of obtaining a polyethylene resin foamed molded article having a wide vapor pressure range during molding and a beautiful surface.
  • Polyethylene resin foam particles having a specific average cell diameter and open cell ratio which will be described later, using a foaming agent containing carbon dioxide gas, have a wide vapor pressure range at the time of molding, and have a beautiful surface. Therefore, the effect of the present invention is more manifested.
  • the amount of foaming agent used in the present invention varies depending on the type of polyethylene resin particles used, the type of foaming agent, the target foaming ratio, etc., and cannot be specified unconditionally, but with respect to 100 parts by weight of polyethylene resin particles.
  • the amount is preferably 2 parts by weight or more and 60 parts by weight or less.
  • the aqueous dispersion containing the polyethylene resin particles prepared in the pressure vessel as described above is pressurized to a predetermined pressure with stirring and heated to a predetermined temperature for a certain period of time. (Normally 5 to 180 minutes, preferably 10 to 60 minutes). Thereafter, the pressurized aqueous dispersion containing polyethylene resin particles is released into a low-pressure atmosphere (usually atmospheric pressure) by opening a valve provided at the lower part of the pressure-resistant container. Resin foam particles are produced.
  • the atmospheric temperature at which the aqueous dispersion is released is usually room temperature.
  • a heating medium such as water vapor to heat the atmosphere to 60 to 120 ° C., preferably 80 to 110 ° C.
  • the predetermined temperature for heating the inside of the pressure vessel in the present invention (hereinafter sometimes referred to as “foaming temperature”) varies depending on the melting point [Tm (° C.)], type, etc. of the polyethylene-based resin particles used. Although it cannot be specified, it is preferable to heat to a temperature higher than the softening temperature of the polyethylene resin particles, and it is more preferable to heat to Tm ⁇ 30 (° C.) or higher and Tm + 10 (° C.) or lower.
  • the melting point of the polyethylene resin particles means that the polyethylene resin particles are heated from 10 ° C. to 190 ° C. at a heating rate of 10 ° C./min using a differential scanning calorimeter DSC. After melting the resin particles, the temperature was decreased from 190 ° C. to 10 ° C. at a temperature decrease rate of 10 ° C./min and crystallized, and then the temperature was further increased from 10 ° C. to 190 ° C. at a temperature increase rate of 10 ° C./min. It is a value obtained from the DSC curve obtained at this time as the melting peak temperature at the second temperature increase.
  • the polyethylene resin expanded particles (single-stage expanded particles) obtained by single-stage expansion may be used as they are for in-mold foam molding, or may be expanded again and polyethylene having the desired expansion ratio. After the resin-based resin foamed particles, they may be used for in-mold foam molding.
  • the step of further foaming the first-stage expanded particles may be referred to as “two-stage expansion”.
  • polyethylene resin foam particles obtained by two-stage foaming may be referred to as “two-stage foamed particles”.
  • the two-stage foaming in the present invention a known method can be adopted, for example, as follows. Put the polyethylene resin foam particles in a pressurized tank, pressurize with an inorganic gas of a predetermined pressure, introduce the inorganic gas into the polyethylene resin foam particles, and leave it for a certain time, the internal pressure of the foam particles is atmospheric pressure After further increase, the polyethylene resin expanded particles are preferably heated with steam (water vapor) of 0.01 MPa-G or more and 0.15 MPa-G or less, more preferably 0.02 MPa-G or more and 0.10 MPa-G or less. To make two-stage foaming.
  • steam water vapor
  • the internal pressure of the polyethylene resin expanded particles is preferably adjusted to 0.05 to 0.70 MPa-G, preferably 0.10 to 0.50 MPa-G.
  • the expansion ratio tends not to increase so much, and when it exceeds 0.70 MPa-G, the bubbles constituting the polyethylene resin expanded particles are continuously formed by two-stage expansion. It becomes easy to form bubbles, and when the foamed particles are filled in a mold and subjected to in-mold foam molding, the resulting polyethylene-based resin foam molded article may shrink.
  • G in the unit of pressure MPa-G indicates a gauge pressure.
  • the inorganic gas used in the two-stage foaming in the present invention is not particularly limited, and examples thereof include air, nitrogen, carbon dioxide gas, etc. Air is preferable from the viewpoint of safety and environmental compatibility.
  • the expansion ratio of the polyethylene resin expanded particles in the present invention is not particularly limited, but the effect of the present invention is remarkable in that the shrinkage after molding is small (that is, the shrinkage ratio against the mold is small) even at a high expansion ratio. From the above, it is preferable that the expansion ratio of the polyethylene-based resin foam particles to be molded is 15 times or more and 30 times or less. When the expansion ratio of the polyethylene resin foam particles to be used for molding is less than 15 times, it is possible to obtain a foamed molded article having a small mold shrinkage rate without depending on the present invention when evaluated only from the viewpoint of shrinkage after molding. However, the effect of the present invention becomes remarkable at 15 times or more. When the expansion ratio exceeds 30 times, the mechanical strength of the foamed molded product tends to decrease.
  • the average cell diameter of the polyethylene resin expanded particles of the present invention is preferably 200 ⁇ m or more and 700 ⁇ m or less, and more preferably 300 ⁇ m or more and 600 ⁇ m or less.
  • the average cell diameter of the polyethylene resin foamed particles is less than 200 ⁇ m, the vapor pressure width during molding tends to be narrow, and the shrinkage of the resulting polyethylene resin foam molded product tends to increase.
  • the average cell diameter exceeds 700 ⁇ m, the cells are liable to form a continuous bubble, and the appearance of the resulting polyethylene-based resin foam molded article tends to deteriorate.
  • the vapor pressure width during molding tends to be wider, which is a more preferable embodiment.
  • Such polyethylene foamed resin particles having an average cell diameter of 300 ⁇ m or more and 600 ⁇ m or less tend to be difficult to obtain by the above-mentioned one-stage foaming, but can be easily obtained by carrying out two-stage foaming.
  • the ratio of the bubbles whose average cell diameter is within ⁇ 15% is preferably 80% or more of the entire expanded particles, and 90% or more. It is more preferable that When the ratio of the bubbles whose average bubble diameter is within ⁇ 15% is 80% or more of the entire foamed particles, the molded product obtained from the foamed particles has a uniform color and is beautiful.
  • the ratio of the bubbles whose bubble diameter is within an average bubble diameter of ⁇ 15% is related to the total bubbles in the region of 3000 ⁇ m ⁇ 3000 ⁇ m near the center of the expanded particle cross section when the expanded particle cross section is observed with an optical microscope.
  • the number of bubbles whose average bubble diameter is within ⁇ 15% is measured and divided by the total number of bubbles.
  • the bubble diameter is measured by the following method. A straight line having the maximum length d 1 in the bubble is drawn, a distance d 2 between the contact points of the perpendicular bisector of the straight line and the bubble is obtained, and an average value of d 1 and d 2 is defined as the bubble diameter.
  • a bubble that does not contain the entire bubble in the region for example, a bubble that is contained in the region by half of the bubble is excluded from the measurement.
  • the foamed polyethylene resin particles of the present invention have a uniform cell diameter, the foamability at the time of molding becomes uniform, and the surface beauty of the resulting foamed molded article is excellent.
  • the bubble diameter in the polyethylene resin expanded particles is non-uniform, there is a tendency that voids are conspicuous because the expanded properties differ between the expanded particles even under the same molding conditions.
  • the linear low-density polyethylene resin is a copolymer of ethylene and an ⁇ -olefin having 6 and / or 8 carbon atoms;
  • the density is 0.920 g / cm 3 or more and less than 0.940 g / cm 3 ;
  • the melt flow rate (MFR) is 0.1 to 5.0 g / 10 min.
  • MFR molecular weight distribution
  • GPC gel permeation chromatograph
  • the aforementioned hydrophilic compound in the aforementioned amount. More preferably, at least one selected from the group consisting of glycerin, polyethylene glycol and melamine is contained in an amount of 0.1 part by weight or more and 2 parts by weight or less based on 100 parts by weight of the linear low density polyethylene resin. It is particularly preferable to contain 0.1 to 2 parts by weight of polyethylene glycol.
  • the open cell ratio of the polyethylene resin expanded particles in the present invention is preferably 12% or less, more preferably 10% or less, and particularly preferably 6% or less.
  • the open cell ratio exceeds 12%, shrinkage occurs when in-mold foam molding is performed, and the surface beauty and compressive strength of the polyethylene-based resin in-mold foam molding tend to decrease.
  • the average cell diameter is preferably 200 ⁇ m or more and 700 ⁇ m or less, and the open cell rate is preferably 12% or less.
  • the method using water as a foaming agent cannot achieve both an average cell diameter and an open cell ratio.
  • carbon dioxide gas is used as the foaming agent, both the average cell diameter and the open cell ratio can be achieved, but there is a problem that the range of vapor pressure that can be molded when performing in-mold foam molding is narrow.
  • the present invention uses a linear low-density polyethylene resin that is a copolymer of ethylene and an ⁇ -olefin having 6 and / or 8 carbon atoms, so that an average cell diameter and an open cell ratio are obtained. As a result, the inventors have found that the range of vapor pressures that can be molded also increases.
  • linear low density polyethylene resin, polyethylene resin expanded particles, and polyethylene resin expanded particles used in the present invention are all non-crosslinked.
  • “non-crosslinked” specifically refers to those having a gel fraction insoluble in hot xylene of 3.0% by weight or less.
  • the gel fraction is a weight ratio of the gel component amount measured by the following method to the original resin weight. That is, 0.5 g of linear low density polyethylene resin, polyethylene resin expanded particles, or polyethylene resin expanded particles are put in a 200 mesh wire mesh bag, and the resin or particles do not come out of the bag. Fold the end of the wire mesh so that.
  • the wire mesh bag is immersed in 50 ml of xylene boiled under atmospheric pressure for 3 hours, and then cooled and taken out from xylene three times in total.
  • the wire mesh bag taken out is dried overnight at room temperature, then dried in an oven at 150 ° C. for 1 hour, and then naturally cooled to room temperature.
  • the weight of the component remaining in the wire mesh bag after cooling is measured to obtain the gel component weight.
  • the polyethylene resin foamed particles of the present invention are non-crosslinked, a polyethylene resin foamed molded article having a wide vapor pressure range during molding and a beautiful surface can be obtained.
  • the cross-linked polyethylene-based resin expanded particles the vapor pressure width at the time of molding tends to be narrow, and the surface property of the polyethylene-based resin expanded molded body also tends to be lowered.
  • the foamed polyethylene resin particles obtained as described above are filled in a mold having a predetermined shape and heated with steam or the like, so that the foamed particles are fused together, so-called in-mold foaming.
  • a polyethylene resin foam molded article can be obtained.
  • an in-mold foam molding method for example, B) Pressurizing the polyethylene resin expanded particles with an inorganic gas (for example, air, nitrogen, carbon dioxide, etc.) to impregnate the polyethylene resin expanded particles with an inorganic gas to give a predetermined internal pressure, Filling and heat-sealing with steam, B) A method in which polyethylene resin foam particles are compressed by gas pressure and filled in a mold, and heat recovery is performed with water vapor using the recovery force of the polyethylene resin foam particles. C) A method in which polyethylene resin foamed particles are filled in a mold without any pretreatment and heat-sealed with water vapor. Such a method can be used.
  • an inorganic gas for example, air, nitrogen, carbon dioxide, etc.
  • the polyethylene resin expanded particles are then provided.
  • the method include molding by time, fusing the polyethylene resin pre-expanded particles together, cooling the mold by water cooling, then opening the mold, and obtaining a polyethylene resin in-mold foam molding.
  • the thus obtained polyethylene-based resin foam molded article has a small mold dimensional shrinkage, little deformation, and good surface elongation.
  • the dimensional shrinkage ratio of the polyethylene-based resin foam molded body in the present invention differs depending on the resin used, the foaming ratio of the foamed particles, the vapor pressure during molding, and the shape of the mold, it cannot be specified unconditionally.
  • polyethylene-based resin expanded particles having an expansion ratio of 20 times or more approximately 2 to 4% is preferable.
  • the steam pressure at the time of molding increases, and the expansion force (foaming force) of the expanded particles increases, so that the dimensional shrinkage against the mold generally decreases.
  • the vapor pressure becomes too high, the foamed particles shrink due to heat, so that the shrinkage ratio against the mold tends to increase.
  • the dimensional shrinkage ratio of the mold tends to increase.
  • the deformation of the polyethylene-based resin foam molded body in the present invention is influenced by the resin used, the expansion ratio of the expanded particles, the vapor pressure at the time of molding, and the shape of the mold.
  • the lower the expansion ratio of the expanded particles used for in-mold foam molding the higher the strength, and the easier it is to maintain the shape of the mold.
  • the lower the vapor pressure during molding the less deformation after molding and the easier it is to return to the shape of the mold upon drying.
  • the higher the steam pressure the larger the deformation, and there is a tendency that the deformation does not return even after the drying process.
  • the surface elongation of the polyethylene resin foam molded article in the present invention is preferably in a state where there are no voids between the foamed particles because the surface of the foam molded article is beautiful.
  • the foaming force of the foamed particles is weak and many voids are generated.
  • voids may also occur when the vapor pressure is too high.
  • the range of the vapor pressure in the main heating step in which a good molded body is obtained is defined as “appropriate vapor pressure width”.
  • the vapor pressure in the main heating step is lower than the lower limit value of the appropriate vapor pressure width, there is a problem that the inside of the obtained molded body is not fused, the surface is poorly stretched, and voids are conspicuous.
  • the steam pressure in this heating process is higher than the upper limit of the appropriate steam pressure width, there is a problem that deformation after molding is large, deformation does not return after drying, and the dimensional shrinkage ratio against the mold is large.
  • the vapor pressure is too high, the molded body shrinks and a usable molded body may not be obtained.
  • melt flow rate (MFR) of the polyethylene resin was measured using an MI measuring instrument described in JIS K7210, with an orifice of 2.0959 ⁇ 0.005 mm ⁇ , an orifice length of 8.000 ⁇ 0.025 mm, a load of 2160 g, and 190 ⁇ 0.2. Measured under the condition of ° C.
  • Mw / Mn The molecular weight distribution (Mw / Mn) by GPC of the polyethylene resin was measured under the following conditions.
  • Measuring instrument Alliance GPC2000 type column manufactured by Waters: TSKgel GMH6-HT 2 TSKgel GMH6-HTL 2 [each inner diameter 7.5 mm ⁇ length 300 mm; manufactured by Tosoh Corporation]
  • Mobile phase o-dichlorobenzene for high performance liquid chromatography (containing 0.025% BHT)
  • Flow rate 1.0 mL / min
  • ⁇ Gel fraction> In a 200 mesh wire mesh bag, 0.5 g of linear low density polyethylene resin, polyethylene resin expanded particles, or polyethylene resin expanded particles are put so that the resin or particles do not come out of the bag. Fold the end of the wire mesh.
  • the wire mesh bag is immersed in 50 ml of xylene boiled under atmospheric pressure for 3 hours, and then cooled and taken out from xylene three times in total.
  • the wire mesh bag taken out is dried overnight at room temperature, then dried in an oven at 150 ° C. for 1 hour, and then naturally cooled to room temperature. The weight of the component remaining in the wire mesh bag after cooling is measured to obtain the gel component weight.
  • gel fraction of the polyethylene-type resin expanded particle of an Example and a comparative example description was 1.0 weight% or less, and was a non-crosslinked polyethylene-based resin expanded particle.
  • ⁇ Bubble diameter uniformity> When the cross section of the expanded particle was observed with an optical microscope [manufactured by KEYENCE, microscope VHX-100], the bubble diameter was measured for all the bubbles in the region of 3000 ⁇ m ⁇ 3000 ⁇ m near the center of the expanded particle cross section, and the average cell The ratio of bubbles within a diameter of ⁇ 15% was determined, and the bubble diameter uniformity (bubble diameter variation) was evaluated according to the following criteria.
  • the bubble diameter is measured by the following method. A straight line having the maximum length d 1 in the bubble was drawn, the distance d 2 between the contact points of the perpendicular bisector of the straight line and the bubble was determined, and the average value of d 1 and d 2 was taken as the bubble diameter.
  • ⁇ The ratio of the bubbles whose bubble diameter is within the average bubble diameter ⁇ 15% is 90% or more of the whole.
  • X The proportion of the bubbles whose bubble diameter is within ⁇ 15% of the average bubble diameter is less than 80% of the total.
  • ⁇ Vapor pressure range during molding and proper steam pressure> After the moisture of the obtained polyethylene-based resin expanded particles was blown, the mold was filled in a mold having a molding space of length 400 ⁇ width 300 ⁇ thickness 50 mm, and the inside of the mold chamber was heated with steam for 10 seconds. Thereafter, the exhaust valve was closed and heated with steam for 10 seconds (hereinafter referred to as “main heating step”), thereby fusing the expanded particles. Subsequently, the vapor in the mold was evacuated, the inside of the mold and the surface of the molded body were water-cooled, and then the molded body was taken out to obtain a polyethylene resin foam molded body.
  • Molding was performed by changing the set steam pressure in this heating step by 0.01 MPa within a range of 0.08 to 0.15 MPa-G.
  • the holding time at the set pressure was 4 seconds.
  • ⁇ or ⁇ level was defined as “appropriate steam pressure range”.
  • the most balanced steam pressure was determined as “optimum steam pressure” in terms of fusion property, mold dimensional shrinkage, and surface aesthetics.
  • the vapor pressure width at the time of molding was evaluated according to the following criteria.
  • ⁇ The proper steam pressure width is 0.03 MPa or more.
  • ⁇ The proper steam pressure width is 0.02 MPa or more and less than 0.03 MPa.
  • X The proper steam pressure width is less than 0.02 MPa.
  • the fusion rate is 60% or more and less than 80%.
  • X The fusion rate is less than 60%.
  • Example 1 [Preparation of polyethylene resin particles]
  • 4MP 4-methyl-1-pentene as a copolymerized ⁇ -olefin
  • the dry blended mixture is put into a 50 mm ⁇ twin screw extruder, melt kneaded at a resin temperature of 220 ° C., extruded into a strand through a circular die attached to the tip of the extruder, water cooled, and then cut with a cutter.
  • Polyethylene resin particles having a weight of 4.5 mg / grain were obtained.
  • the set steam pressure in this heating process is changed within a range of 0.08 to 0.15MPa-G by 0.01MPa and molding is performed. Evaluated. Here, out of the heating time of 10 seconds in the main heating step, the holding time at the set pressure was 4 seconds. Table 1 shows the evaluation results regarding the obtained polyethylene resin-in-mold foam. In addition, the molded body evaluation (fusing property, dimensional stability against mold, and surface aesthetics) in the table was obtained by in-mold foam molding at the optimum vapor pressure (vapor pressure of 0.11 MPa-G).
  • the present invention relates to a foam in a polyethylene resin mold.
  • Example 2 Polyethylene resin particles were obtained by the same operation as in Example 1.
  • Example 3 Single-stage expanded particles were obtained by the same operation as in Example 1 except that the foaming temperature was changed to 123.0 ° C. with respect to the obtained polyethylene resin. After the water of the obtained first-stage expanded particles was blown, it was placed in a pressure vessel and pressurized with air to impregnate the first-stage expanded particles with air, and an internal pressure of 0.24 MPa-G was applied.
  • the present invention relates to a foam in a polyethylene resin mold.
  • the present invention relates to a foam in a polyethylene resin mold.
  • Table 1 shows the evaluation results regarding the obtained one-stage expanded particles, two-stage expanded particles, and the polyethylene-based resin-in-mold foam.
  • the molded body evaluation (fusing property, dimensional stability against mold, and surface aesthetics) in the table was obtained by in-mold foam molding at the optimum vapor pressure (vapor pressure of 0.11 MPa-G).
  • the present invention relates to a foam in a polyethylene resin mold.
  • Table 1 shows the evaluation results regarding the obtained one-stage expanded particles, two-stage expanded particles, and the polyethylene-based resin-in-mold foam.
  • the molded body evaluation (fusing property, dimensional stability against mold, and surface aesthetics) in the table was obtained by in-mold foam molding at the optimum vapor pressure (vapor pressure of 0.11 MPa-G).
  • the present invention relates to a foam in a polyethylene resin mold.
  • Example 7 In [Production of polyethylene-based resin expanded particles], the same operation as in Example 2 was carried out under the conditions described in Table 1 except that the hydrophilic compound was not used. A resin foam molding was obtained. Table 1 shows the evaluation results regarding the obtained one-stage expanded particles, two-stage expanded particles, and the polyethylene-based resin-in-mold foam. In addition, the molded body evaluation (fusing property, dimensional stability against mold, and surface aesthetics) in the table was obtained by in-mold foam molding at the optimum vapor pressure (vapor pressure of 0.11 MPa-G). The present invention relates to a foam in a polyethylene resin mold.
  • Example 8 In [Preparation of polyethylene resin expanded particles], the types and amounts of the hydrophilic compounds are respectively 0.5 parts by weight of polyethylene glycol [manufactured by Lion Corporation, PEG300], melamine [manufactured by Nissan Chemical Industries, Ltd.] 0 Except for the change to 2 parts by weight, the same operations as in Example 2 were performed under the conditions described in Table 1, and single-stage expanded particles, double-stage expanded particles, and a polyethylene-based resin foam molded article were obtained. Table 1 shows the evaluation results regarding the obtained one-stage expanded particles, two-stage expanded particles, and the polyethylene-based resin-in-mold foam.
  • the present invention relates to a foam in a polyethylene resin mold.
  • Example 10 Preparation of polyethylene resin particles
  • talc manufactured by Hayashi Kasei Co., Ltd., Talcan powder PK-S
  • monoglyceride as an antistatic agent
  • Riken Vitamin Co., Ltd. Riquemar S-100A
  • dry blending 1.0 part by weight, the same operation as in Example 1 was performed to obtain 1.3 mg / grain of polyethylene resin particles.
  • Example 2 In [Production of polyethylene-based resin foamed particles] and [Production of polyethylene-based resin-in-mold foam], the same operation as in Example 2 was performed to obtain one-stage foamed particles, two-stage foamed particles, and a polyethylene-based resin foam molded article. Obtained.
  • Table 1 shows the evaluation results regarding the obtained one-stage expanded particles, two-stage expanded particles, and the polyethylene-based resin-in-mold foam.
  • the molded body evaluation (fusing property, dimensional stability against mold, and surface aesthetics) in the table was obtained by in-mold foam molding at the optimum vapor pressure (vapor pressure of 0.11 MPa-G).
  • the present invention relates to a foam in a polyethylene resin mold.
  • Example 11 In [Preparation of polyethylene resin foamed particles], 0.1 part by weight of talc [manufactured by Hayashi Kasei Co., Ltd., Talcan Powder PK-S] is further added to 100 parts by weight of the linear low density polyethylene resin.
  • Example 1 except that 0.5 parts by weight of a monoglyceride [manufactured by Riken Vitamin Co., Ltd., Riquemar S-100A] as an inhibitor and 1.0 part by weight of carbon black [manufactured by CABOT, N330] as a colorant were dry blended. The same operation was performed to obtain one-stage expanded particles, two-stage expanded particles, and a polyethylene resin foam molded article.
  • Table 1 shows the evaluation results regarding the obtained one-stage expanded particles, two-stage expanded particles, and the polyethylene-based resin-in-mold foam.
  • the molded body evaluation (fusing property, dimensional stability against mold, and surface aesthetics) in the table was obtained by in-mold foam molding at the optimum vapor pressure (vapor pressure of 0.11 MPa-G).
  • the present invention relates to a foam in a polyethylene resin mold.
  • Table 1 shows the evaluation results regarding the obtained one-stage expanded particles, two-stage expanded particles, and the polyethylene-based resin-in-mold foam.
  • the molded body evaluations (fusing property, mold dimensional stability, surface aesthetics) in the table were obtained by in-mold foam molding at the optimum vapor pressure (vapor pressure of 0.12 MPa-G).
  • the present invention relates to a foam in a polyethylene resin mold.
  • Table 1 shows the evaluation results regarding the obtained one-stage expanded particles, two-stage expanded particles, and the polyethylene-based resin-in-mold foam.
  • the molded body evaluations (fusing property, mold dimensional stability, surface aesthetics) in the table were obtained by in-mold foam molding at the optimum vapor pressure (vapor pressure of 0.12 MPa-G).
  • the present invention relates to a foam in a polyethylene resin mold.
  • Example 14 [Preparation of polyethylene resin particles] Polyethylene resin particles were obtained by the same operation as in Example 1. [Preparation of expanded polyethylene resin particles] After adding 25 parts by weight of isobutane as a foaming agent to the obtained polyethylene-based resin particles and heating to a foaming temperature of 119.0 ° C., isobutane was additionally injected, and the internal pressure of the autoclave was 1.6 MPa-G. Single-stage expanded particles were obtained in the same manner as in Example 1 except that the pressure was increased to the expansion pressure.
  • the present invention relates to a foam in a polyethylene resin mold.
  • the present invention relates to a foam in a polyethylene resin mold.
  • Table 2 shows the evaluation results regarding the obtained one-stage expanded particles, two-stage expanded particles, and the polyethylene resin-in-mold foam.
  • the molded body evaluations in the table were obtained by in-mold foam molding at an optimum vapor pressure (vapor pressure of 0.10 MPa-G).
  • the present invention relates to a foam in a polyethylene resin mold.
  • Single-stage expanded particles, double-stage expanded particles and a polyethylene-based resin foam molded article were obtained.
  • Table 2 shows the evaluation results regarding the obtained one-stage expanded particles, two-stage expanded particles, and the polyethylene resin-in-mold foam.
  • the molded body evaluations (fusing property, dimensional stability against mold, and surface aesthetics) in the table were obtained by in-mold foam molding at the optimum vapor pressure (vapor pressure of 0.13 MPa-G).
  • the present invention relates to a foam in a polyethylene resin mold.
  • the molded body evaluations (fusing property, dimensional stability against mold, and surface aesthetics) in the table were obtained by in-mold foam molding at the optimum vapor pressure (vapor pressure of 0.13 MPa-G).
  • the present invention relates to a foam in a polyethylene resin mold.
  • the resulting single-stage expanded particles were two-stage expanded under the conditions shown in Table 2, but the foamed particles were broken to increase the open-cell ratio, resulting in two-stage expanded particles with a reduced expansion ratio. Molding was stopped.
  • Table 2 shows the evaluation results regarding the obtained one-stage expanded particles, two-stage expanded particles, and the polyethylene resin-in-mold foam.
  • the molded body evaluation (fusing property, dimensional stability against mold, and surface aesthetics) in the table was obtained by in-mold foam molding at the optimum vapor pressure (vapor pressure of 0.11 MPa-G).
  • the present invention relates to a foam in a polyethylene resin mold.
  • Example 9 [Preparation of polyethylene resin particles] The same operation as in Example 7 was performed to obtain polyethylene resin particles containing no hydrophilic compound. [Preparation of expanded polyethylene resin particles] In a pressure resistant autoclave having a capacity of 0.3 m 3 , 100 parts by weight (75 kg) of the obtained polyethylene resin particles, 250 parts by weight of water, and tribasic calcium phosphate as a sparingly water-soluble inorganic compound [made by Taihei Chemical Industry Co., Ltd.] 4.0 After charging 0.8 parts by weight of sodium alkyl sulfonate [La Kamul PS, manufactured by Kao Corporation] as a surfactant, nitrogen gas was injected under pressure to 1.5 MPa-G with stirring.
  • sodium alkyl sulfonate La Kamul PS, manufactured by Kao Corporation
  • the autoclave contents were heated and heated to a foaming temperature of 125.0 ° C.
  • the internal pressure of the autoclave was 2.2 MPa-G.
  • nitrogen gas was additionally injected to increase the internal pressure of the autoclave to a foaming pressure of 3.5 MPa-G.
  • bulb of the autoclave lower part was opened, the autoclave content was discharge
  • the resulting single-stage expanded particles were two-stage expanded under the conditions shown in Table 2, but the foamed particles were broken to increase the open-cell ratio, resulting in two-stage expanded particles with a reduced expansion ratio. Molding was stopped.
  • polyethylene resin foamed particles of the present invention a polyethylene resin foam molded article having a wide vapor pressure range, a small mold dimensional shrinkage ratio, and a beautiful surface can be easily obtained. Obtainable.
  • the obtained polyethylene-based resin foam molded article is used for various applications as a buffer packaging material, a heat insulating material, and the like.

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Abstract

Cette invention concerne des particules de résine polyéthylène, à base d'une résine polyéthylène basse densité linéaire utilisée à titre de résine de base, destinée à être expansée, ladite résine polyéthylène basse densité linéaire étant un copolymère d'éthylène et d'une alpha-oléfine ayant 6 et/ou 8 atomes de carbone, une densité de 0,920 à moins de 0,940 g/cm3, un indice de fluidité à chaud (MFR) de 0,1 à 5,0 g/10 minutes, et une distribution des poids moléculaires (Mw/Mn), mesurée par chromatographie par perméation de gel (GPC), de 3 à moins de 5, qui permettent de fabriquer des articles moulés en résine polyéthylène expansée présentant de belles surfaces et de bas taux de retrait par rapport aux dimensions du moule, dans la large plage de pressions de vapeur permettant d'obtenir d'excellents articles moulés pendant le moulage ; et des particules expansées de résine polyéthylène ayant un diamètre d'alvéoles moyen de 200 à 700 μm, et un taux d'alvéoles ouvertes d'au moins 12 %.
PCT/JP2012/071633 2011-08-29 2012-08-28 Particules expansées de résine polyéthylène et articles moulés obtenus à partir de celles-ci Ceased WO2013031745A1 (fr)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014136933A1 (fr) * 2013-03-08 2014-09-12 株式会社カネカ Procédé de fabrication de particules de résine de polypropylène expansée
WO2016158686A1 (fr) * 2015-03-27 2016-10-06 株式会社カネカ Procédé de fabrication d'un article moulé en mousse de résine polyéthylène
JPWO2021106354A1 (fr) * 2019-11-29 2021-06-03
WO2022196372A1 (fr) 2021-03-15 2022-09-22 株式会社ジェイエスピー Particule expansée de résine de polyéthylène et son procédé de production
WO2023067953A1 (fr) 2021-10-21 2023-04-27 株式会社ジェイエスピー Particules de mousse de résine à base de polyéthylène ainsi que procédé de production de celles-ci
WO2023067954A1 (fr) 2021-10-21 2023-04-27 株式会社ジェイエスピー Particules de mousse de résine à base de polyéthylène ainsi que procédé de production de celles-ci
EP4506400A4 (fr) * 2022-06-01 2025-09-10 Jsp Corp Particules de mousse de résine de polyoléfine et leur procédé de fabrication

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