Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/38—Moulds or cores; Details thereof or accessories therefor characterised by the material or the manufacturing process
  • B29C33/40—Plastics, e.g. foam or rubber
• • 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
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
  • C08K3/013—Fillers, pigments or reinforcing additives
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L29/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical; Compositions of hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers
  • C08L29/02—Homopolymers or copolymers of unsaturated alcohols
  • C08L29/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids

Definitions

• the present invention aims to provide a core resin composition that exhibits high heat resistance and can be used to produce cores that do not deform even under the molding conditions of super engineering plastics. It also aims to provide a core made using this core resin composition.
• the present disclosure (3) is the resin composition for a core according to the present disclosure (1) or (2), in which the content of the particulate filler is 5% by mass or more and 70% by mass or less.
• the present disclosure (4) is the core resin composition according to the present disclosure (1), (2), or (3), in which the polyvinyl alcohol resin has a weight average molecular weight (Mw) of 200,000 or less, a degree of saponification of 72% or more and 99.8% or less, and a viscosity of a 4% by mass aqueous solution of 30 mPa s or less.
• Mw weight average molecular weight
• the present disclosure (8) is a core resin composition according to the present disclosure (1), (2), (3), (4), (5), (6), or (7), which is in the form of pellets.
• the present disclosure (9) is a core made using the core resin composition of the present disclosure (1), (2), (3), (4), (5), (6), (7), or (8). The present invention will be described in detail below.
• the inventors investigated the addition of a particulate filler to a core resin composition and discovered that by combining a polyvinyl alcohol resin with a particulate filler and setting the total surface area of the particulate filler within a specified range, high heat resistance could be achieved, leading to the completion of the present invention.
• the core resin composition contains a polyvinyl alcohol resin.
• a polyvinyl alcohol resin By using a polyvinyl alcohol resin, it can be easily removed from the molded body by, for example, immersing it in water.
• the degree of polymerization of the polyvinyl alcohol resin is preferably not more than 4000. When the degree of polymerization is not more than 4000, the resin can exhibit sufficient solubility in water.
• the degree of polymerization is more preferably 180 or more, even more preferably 200 or more, and even more preferably 220 or more, and is preferably 3400 or less, more preferably 2300 or less, even more preferably 1200 or less, and even more preferably 900 or less.
• the degree of polymerization can be determined, for example, by measuring polyvinyl acetate before saponification by gel permeation chromatography (GPC) or by measuring the viscosity of an aqueous solution in accordance with JIS K6726.
• the weight average molecular weight (Mw) of the polyvinyl alcohol resin is preferably 8,000 or more, more preferably 9,000 or more, even more preferably 10,000 or more, even more preferably 11,000 or more, particularly preferably 14,000 or more, especially more preferably 17,000 or more, and is preferably 200,000 or less, more preferably 150,000 or less, even more preferably 100,000 or less, even more preferably 50,000 or less, especially preferably 40,000 or less, especially more preferably 32,000 or less, and most preferably 24,000 or less.
• the weight average molecular weight (Mw) of the entire polyvinyl alcohol resin is calculated based on the weight average molecular weight of each resin and its weight fraction, and is obtained by summing the values obtained by multiplying the weight average molecular weight of each polyvinyl alcohol resin by its weight fraction.
• the weight average molecular weight (Mw) is preferably 8000 or more, more preferably 9000 or more, even more preferably 10000 or more, even more preferably 11000 or more, particularly preferably 14000 or more, particularly more preferably 17000 or more, preferably 200000 or less, more preferably 150000 or less, even more preferably 100000 or less, even more preferably 50000 or less, particularly preferably 40000 or less, particularly more preferably 320000 or less, and most preferably 24000 or less.
• the number average molecular weight (Mn) of the above polyvinyl alcohol resin is preferably 4,000 or more, more preferably 4,500 or more, even more preferably 5,000 or more, and is preferably 90,000 or less, more preferably 60,000 or less, even more preferably 30,000 or less.
• the weight average molecular weight (Mw) and number average molecular weight (Mn) can be determined, for example, by gel permeation chromatography (GPC), by measuring a polyvinyl ester before saponification by GPC, by measuring a polyvinyl ester obtained by re-esterifying a polyvinyl alcohol resin by GPC, or by measuring the viscosity of an aqueous solution in accordance with JIS K 6726.
• GPC gel permeation chromatography
• the polyvinyl alcohol resin preferably has a viscosity of 30 mPa ⁇ s or less in a 4% by mass aqueous solution, which provides fluidity suitable for injection molding and water solubility suitable for use as a core.
• the viscosity of the 4% by mass aqueous solution is preferably 3 mPa ⁇ s or more, more preferably 5 mPa ⁇ s or more, and is preferably 20 mPa ⁇ s or less, more preferably 10 mPa ⁇ s or less.
• the viscosity of the 4% by mass aqueous solution can be measured, for example, by a method in accordance with JIS K 6276 3.11.1 Rotational Viscometer Method.
• the polyvinyl alcohol resin may be an unmodified polyvinyl alcohol resin or a modified polyvinyl alcohol resin, where the modified polyvinyl alcohol resin refers to a polyvinyl alcohol resin having structural units other than vinyl ester units and vinyl alcohol units.
• the modified polyvinyl alcohol resin include those modified with a hydrophilic modifying group such as a sulfonic acid group, a pyrrolidone ring group, an amino group, a carboxyl group, etc. These hydrophilic groups include not only the functional groups but also their salts such as sodium salts and potassium salts.
• the content of structural units having a modifying group in the above polyvinyl alcohol resin is preferably 1 mol% or more, more preferably 3 mol% or more, and particularly preferably 5 mol% or more, and is preferably 20 mol% or less, more preferably 15 mol% or less, and particularly preferably 12 mol% or less.
• the polyvinyl alcohol resin is obtained by polymerizing a vinyl ester to obtain a polymer according to a conventional method, and then saponifying, i.e., hydrolyzing, the polymer.
• An alkali or acid is generally used as the saponification catalyst.
• vinyl esters examples include vinyl acetate, vinyl formate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl versatate, vinyl laurate, vinyl stearate, and vinyl benzoate.
• the method for polymerizing vinyl esters is not particularly limited, but examples include solution polymerization, bulk polymerization, and suspension polymerization.
• the polyvinyl alcohol resin may be a saponified polymer of a vinyl ester and another unsaturated monomer.
• unsaturated monomers include monomers other than the vinyl esters and having an unsaturated double bond such as a vinyl group.
• Specific examples include olefins, (meth)acrylic acid and salts thereof, (meth)acrylic acid esters, unsaturated acids other than (meth)acrylic acid, salts and esters thereof, (meth)acrylamides, N-vinylamides, vinyl ethers, nitriles, vinyl halides, allyl compounds, vinylsilyl compounds, isopropenyl acetate, sulfonic acid group-containing compounds, and amino group-containing compounds.
• Examples of olefins include ethylene, propylene, 1-butene, and isobutene.
• (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.
• Examples of unsaturated acids other than (meth)acrylic acid, and salts and esters thereof include maleic acid and salts thereof, maleic acid esters, itaconic acid and salts thereof, itaconic acid esters, methylenemalonic acid and salts thereof, and methylenemalonic acid esters.
• Examples of (meth)acrylamides include acrylamide, n-methylacrylamide, N-ethylacrylamide, and N,N-dimethylacrylamide.
• Examples of N-vinylamides include N-vinylpyrrolidone.
• Examples of vinyl ethers include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, and n-butyl vinyl ether.
• the total surface area of the particulate filler does not take into account the areas of depressions and pores, and therefore in the above formula (2), the particulate filler is approximated as a sphere to calculate the total surface area of the particulate filler per unit mass of the resin composition for a core.
• the total surface area is preferably 15 m 2 /g or more, more preferably 20 m 2 /g or more, even more preferably 23 m 2 /g or more, and even more preferably 28 m 2 /g or more.
• the core resin composition may contain an easy-release agent. By including the easy-release agent, the core resin can be more easily removed from the molded body.
• the content of the easy-release agent in the core resin composition is preferably 0.1% by mass or more and 2% by mass or less. By setting the content within this range, the surface smoothness of the inside of the obtained molded product can be sufficiently improved.
• the content of the easy-release agent is more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, and more preferably 1.6% by mass or less, even more preferably 1.1% by mass or less.
• the core resin composition may contain a plasticizer. By including a plasticizer, moldability can be improved.
• the plasticizer may be, for example, a polyhydric alcohol.
• the polyhydric alcohol include ethylene glycol, glycerin, propylene glycol, diethylene glycol, diglycerin, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, trimethylolpropane, polyethylene glycol, polypropylene glycol, erythritol, xylitol, sorbitol, and mannitol.
• the core resin composition may contain a crosslinking agent.
• the crosslinking agent include oxoacids, boron compounds, divalent or higher metal hydroxides, diamines, polyamines, etc. Metal salts of the above acids may also be used.
• the antioxidant may be a known antioxidant, such as a phenolic antioxidant, a phosphorus-based antioxidant, an amine-based antioxidant, or a sulfur-containing antioxidant. It is also possible to use an antioxidant that has both a phenolic functional group and a phosphorus-based functional group in the same molecule.
• phenolic antioxidants examples include acrylate compounds such as 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate and 2,4-di-t-amyl-6-(1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl)phenyl acrylate, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-ethylphenol, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,2 '-methylene-bis(4-methyl-6-t-butylphenol), 4,4'-butylidene-bis(4-methyl-6-t-butylphenol), 4,4'-butylidene-bis(6-t-butyl-m-cresol), 4,4'-thiobis(3-methyl-6-t-butyl
• Antioxidants having both a phenolic functional group and a phosphorus functional group in one molecule include, but are not limited to, phosphite compounds having a phenol skeleton. Specific examples include 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenz[d,f][1,3,2]dioxaphosphepine, 2,10-dimethyl-4,8-di-t-butyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-12H-dibenzo[d,g][1,3,2]dioxaphosphene, 2,4,8,10-tetra-t-butyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphene, and
• the shape of the core resin composition is not particularly limited and may be, for example, pellets, powder, etc.
• the super engineering plastics include highly heat-resistant plastics such as fluororesins such as polyphenylene sulfide (PPS), polyether ether ketone (PEEK), liquid crystal polymer (LCP), polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polyphenylsulfone (PPSU), polysulfone (PSF), polyethersulfone (PES), polyarylate (PAR), polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), and chlorotrifluoroethylene-ethylene copolymer (ECTFE).
• fluororesins such as polyphenylene sulfide (PPS), polyether ether ketone (PEEK), liquid crystal polymer (LCP), polyimide (PI), polyamide
• a molded body having a hollow portion By removing the core from the composite, a molded body having a hollow portion can be obtained.
• the core can be removed, for example, by immersing the composite in water or warm water.
• the shape of the molded body may be a straight shape, or may be various shapes such as an L-shape, an S-shape, a T-shape, etc.
• an L-shaped or S-shaped molded body can be used as a joint.
• the molded article having a hollow portion include a joint for an in-vehicle pipe, a housing for an electronic device, and the like.
• the present invention provides a core resin composition that exhibits high heat resistance and can be used to produce cores that do not deform even under the molding conditions of super engineering plastics. It also provides cores made using this core resin composition.
• the polymerization rate was measured by H-NMR measurement, and found to be 99%.
• the remaining vinyl acetate monomer was removed together with methanol under reduced pressure while adding additional methanol, yielding a methanol solution containing 50% by mass of polyvinyl acetate.
• a methanol solution of sodium hydroxide was added to this methanol solution so that the amount of sodium hydroxide relative to the vinyl acetate was 0.07 mol %.
• Saponification was then carried out at 40°C. The resulting solid was pulverized, washed with methanol, and dried to yield PVA1.
• the degree of saponification of the obtained PVA1 was measured by a method in accordance with JIS K6726.
• Easy-peel agent Monoglyceride stearate ester, Kao Corporation Electrostripper TS-5 The average particle size of the particulate filler was taken from the catalog value. The density was measured using an Accupyc II 1345 manufactured by Shimadzu Corporation.
• Example 1 Polyvinyl alcohol resin, particle filler, and antioxidant were mixed to obtain the formulation shown in Table 1, and the mixture was pelletized at an extrusion temperature of 190°C to 220°C using a processing device "TEM26SX" manufactured by Toshiba Machine Co., Ltd., to obtain pellets of a resin composition for a core.
• Example 2 Polyvinyl alcohol resin, particle filler, and antioxidant were mixed to obtain the formulation shown in Table 1, and pellets of a resin composition for a core were obtained in the same manner as in Example 1.
• Example 9 Polyvinyl alcohol resin, particle filler, antioxidant and easy-release agent were mixed to obtain the formulation shown in Table 1, and pellets of a resin composition for a core were obtained in the same manner as in Example 1.
• Total Surface Area of Particle Filler The total surface area of the particle filler per unit mass of the core resin composition was calculated based on the following formula (1).
• melt flow rate (MFR) Using a melt index tester No. 120-FWP (manufactured by Yasuda Seiki Seisakusho, Ltd.), the melt flow rate (MFR) of the core resin composition was measured according to a method in accordance with ASTM D 1238 under conditions of an initial weight of the core resin composition of 7.5 g, 230°C, a load of 10 kg, and a measurement time interval of 0.25 minutes.

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• Compositions Of Macromolecular Compounds (AREA)

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  • 2025-02-10 WO PCT/JP2025/004382 patent/WO2025177890A1/ja active Pending
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