Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
  • B01J13/02—Making microcapsules or microballoons
  • B01J13/06—Making microcapsules or microballoons by phase separation
  • B01J13/14—Polymerisation; cross-linking
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/42—Nitriles
  • C08F220/44—Acrylonitrile
  • C08F220/46—Acrylonitrile with carboxylic acids, sulfonic acids or salts thereof
• • 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
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/20—Compounding polymers with additives, e.g. colouring
  • C08J3/22—Compounding polymers with additives, e.g. colouring using masterbatch techniques
• • 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
  • C08J9/32—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof from compositions containing microballoons, e.g. syntactic foams
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K3/00—Materials not provided for elsewhere

Definitions

• the present invention relates to thermally expandable microcapsules, masterbatches, and molded articles.
• One method for producing foamed molded articles is to foam a resin material using a blowing agent, which is typically a thermally expandable microcapsule or a chemical blowing agent.
• a blowing agent typically a thermally expandable microcapsule or a chemical blowing agent.
• thermally expandable microcapsules is one in which a shell containing a thermoplastic polymer encapsulates a volatile blowing agent that becomes gaseous at temperatures below the softening point of the thermoplastic polymer.
• Examples of the unsaturated carboxylic acid include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, and cinnamic acid, and unsaturated dicarboxylic acids such as maleic acid, itaconic acid, fumaric acid, citraconic acid, and chloromaleic acid.
• Examples of the monoester of the unsaturated dicarboxylic acid include monomethyl maleate, monoethyl maleate, monobutyl maleate, monomethyl fumarate, monoethyl fumarate, monomethyl itaconate, monoethyl itaconate, and monobutyl itaconate. Of these, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, and itaconic acid are preferred, with methacrylic acid being more preferred.
• Examples of the trifunctional (meth)acrylate include trimethylolpropane tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, triallyl formal tri(meth)acrylate, etc.
• Examples of the tetrafunctional or higher (meth)acrylate include pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc.
• Examples of the monomer (III) include (meth)acrylic acid esters as well as vinyl monomers such as vinyl chloride, vinylidene chloride, vinyl acetate, and styrene. These may be used alone or in combination of two or more. Of these, (meth)acrylic acid esters are preferred, and in particular, alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and n-butyl methacrylate, or methacrylic acid esters containing an alicyclic ring, aromatic ring, or heterocyclic ring, such as cyclohexyl methacrylate, benzyl methacrylate, and isobornyl methacrylate, are preferred.
• alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and n-butyl methacrylate
• t-butyl peroxypivalate examples include t-butyl peroxypivalate, t-hexyl peroxypivalate, t-butyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, and 1,1,3,3-tetramethylbutyl peroxyneodecanoate.
• peroxyesters such as cumyl peroxy neodecanoate and ( ⁇ , ⁇ -bis-neodecanoylperoxy)diisopropylbenzene; bis(4-t-butylcyclohexyl)peroxydicarbonate, di-n-propyl-oxydicarbonate, and diisopropyl peroxydicarbonate.
• peroxydicarbonates such as di(2-ethylethylperoxy)dicarbonate, dimethoxybutylperoxydicarbonate, and di(3-methyl-3-methoxybutylperoxy)dicarbonate.
• examples include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 1,1'-azobis(1-cyclohexanecarbonitrile).
• the shell may contain a metal cation salt.
• a metal cation salt if the copolymer constituting the shell contains a carboxyl group, the metal cation derived from the metal cation salt reacts with the carboxyl group to ionically crosslink the copolymer, thereby improving heat resistance and enabling the formation of thermally expandable microcapsules that do not burst or shrink for a long period of time in high-temperature regions.
• the thermally expandable microcapsules do not burst or shrink even when subjected to molding processes such as kneading molding, calendar molding, extrusion molding, and injection molding, which apply strong shear forces.
• the above-mentioned ionic crosslinking means that crosslinks are formed between free carboxyl groups present as side chains of the copolymer.
• the number of carboxyl groups arranged per one valence of metal cation varies depending on the metal species.
• the metal cation is not particularly limited as long as it reacts with the carboxyl group of the copolymer to ionically crosslink the copolymer, and examples thereof include ions of Li, Na, K, Zn, Mg, Ca, Ba, Sr, Mn, Al, Ti, Ru, Fe, Ni, Cu, Cs, Sn, Cr, and Pb. These may be used alone or in combination of two or more. Among these, Ca, Zn, and Al ions are preferred, and Zn ions are particularly preferred. Although the combination of two or more of the above metal cations is not particularly limited, it is preferable to use an alkali metal ion in combination with a metal cation other than the alkali metal ion.
• the presence of the alkali metal ion activates functional groups such as carboxyl groups, thereby promoting the reaction between the metal cation other than the alkali metal and the carboxyl group of the copolymer.
• the alkali metal include Na, K, and Li.
• the content of the metal cation salt in the shell is 0% by weight or more, preferably 0.5% by weight or more, and preferably 10% by weight or less. By keeping it within this range, heat resistance can be further improved.
• the content is more preferably 0.8% by weight or more, and more preferably 8% by weight or less.
• the shell constituting the thermally expandable microcapsule according to one embodiment of the present invention preferably further contains at least one inorganic compound selected from the group consisting of Si-based compounds and Mg-based compounds.
• the inorganic compound By including the inorganic compound, it is possible to prevent the thermally expandable microcapsules from fusing together in the resin during molding.
• the Si-based compound and Mg-based compound preferably contain oxides, hydroxides, carbonates or hydrogen carbonates of silicon and magnesium. These Si-based compounds and Mg-based compounds may be used alone or in combination of two or more.
• Examples of the Si-based compound include colloidal silica, silicate sol, No. 3 water glass, sodium orthosilicate, sodium metasilicate, etc. Among these, colloidal silica is preferred.
• Examples of the Mg-based compound include magnesium oxide, magnesium hydroxide, magnesium hydroxide, hydrotalcite, dihydrotalcite, magnesium carbonate, basic magnesium carbonate, magnesium calcium carbonate, magnesium phosphate, magnesium hydrogen phosphate, magnesium pyrophosphate, magnesium borate, etc. Of these, magnesium hydroxide is preferred.
• inorganic compounds that may be added include calcium phosphate, aluminum hydroxide, ferric hydroxide, barium sulfate, calcium sulfate, sodium sulfate, calcium oxalate, calcium carbonate, and barium carbonate.
• inorganic salts such as sodium chloride and sodium sulfate, alkali metal nitrites, stannous chloride, stannic chloride, and potassium dichromate may also be added.
• the content of the inorganic compound is 0.01 wt% of the total thermally expandable microcapsules, with a preferred upper limit of 7 wt%. By making it 0.01 wt% or more, fusion between the thermally expandable microcapsules in the resin during molding can be suppressed. By making it 7 wt% or less, resin dispersibility during molding can be further improved. A more preferred lower limit is 0.3 wt%, and a more preferred upper limit is 5 wt%.
• the content of the inorganic compound can be calculated from the weight of the monomer composition and volatile expanding agent that form the thermally expandable microcapsules.
• the shell may further contain stabilizers, UV absorbers, antioxidants, antistatic agents, flame retardants, silane coupling agents, colorants, etc. as needed.
• a volatile expanding agent is encapsulated in the shell as a core agent.
• the core agent does not contain a fluorine atom-containing compound.
• the thermally expandable microcapsules can have excellent gas barrier properties.
• the volatile expanding agent is a substance that becomes gaseous at a temperature below the softening point of the polymer that constitutes the shell, and is preferably a low-boiling organic solvent.
• thermally expandable microcapsules among the above-mentioned volatile expanding agents, it is preferable to use low-boiling-point hydrocarbons having a carbon number of 5 or less. By using such hydrocarbons, it is possible to obtain thermally expandable microcapsules that have a high expansion ratio and start expanding quickly. Furthermore, a thermally decomposable compound that is thermally decomposed into a gaseous form when heated may be used as the volatile expanding agent.
• the thermally expandable microcapsules according to one embodiment of the present invention preferably have a maximum foaming temperature (Tmax) of 240°C or higher.
• Tmax maximum foaming temperature
• the Tmax is more preferably 245°C or higher, and is preferably 290°C or lower, and more preferably 270°C or lower.
• the maximum foaming temperature means the temperature at which the diameter of a thermally expandable microcapsule becomes maximum (maximum displacement) when the diameter of the thermally expandable microcapsule is measured while being heated from room temperature.
• the preferred lower limit of the volume average particle diameter of the thermally expandable microcapsules according to one embodiment of the present invention is 1 ⁇ m, and the preferred upper limit is 100 ⁇ m. If the diameter is 1 ⁇ m or more, the cells in the resulting molded article can be made sufficiently large, thereby enabling a sufficiently high expansion ratio. If the diameter is 100 ⁇ m or less, the cells in the resulting molded article will not become too large, preventing poor appearance. A more preferred lower limit is 3 ⁇ m, and a more preferred upper limit is 50 ⁇ m.
• the volume average particle size of the thermally expandable microcapsules can be measured using a laser diffraction/scattering particle size distribution measuring device or the like.
• the method for producing the thermally expandable microcapsules which are one embodiment of the present invention, is not particularly limited, but they can be produced, for example, by carrying out the steps of preparing an aqueous dispersion medium, dispersing an oily mixture containing a monomer composition, a volatile expanding agent, a metal cation salt, etc. in the aqueous dispersion medium, and polymerizing the monomer composition.
• the monomer composition may contain the nitrile monomer (I), the carboxyl group-containing monomer (II), and other monomers.
• dispersion stabilizers other than silicon dioxide examples include calcium phosphate, magnesium hydroxide, aluminum hydroxide, ferric hydroxide, barium sulfate, calcium sulfate, sodium sulfate, calcium oxalate, calcium carbonate, barium carbonate, and magnesium carbonate.
• the amount of the silicon dioxide-containing dispersion stabilizer added is determined appropriately depending on the particle size of the thermally expandable microcapsules, but the preferred lower limit is 2.5 parts by weight and the preferred upper limit is 7 parts by weight per 100 parts by weight of the oily mixture (oil phase). A more preferred lower limit is 3 parts by weight and a more preferred upper limit is 5 parts by weight.
• the amount of oil phase refers to the total amount of the monomer and volatile expanding agent.
• auxiliary stabilizers examples include condensation products of diethanolamine and aliphatic dicarboxylic acids, and condensation products of urea and formaldehyde.
• Other examples include polyvinylpyrrolidone, polyethylene oxide, polyethyleneimine, tetramethylammonium hydroxide, gelatin, methylcellulose, polyvinyl alcohol, dioctyl sulfosuccinate, sorbitan esters, and various emulsifiers.
• a condensation product and a water-soluble nitrogen compound may also be added.
• a condensation product of diethanolamine and an aliphatic dicarboxylic acid is preferred, and a condensation product of diethanolamine and adipic acid or a condensation product of diethanolamine and itaconic acid is particularly preferred.
• water-soluble nitrogen compounds examples include polyvinylpyrrolidone, polyethyleneimine, polyoxyethylene alkylamines, and polydialkylaminoalkyl(meth)acrylates such as polydimethylaminoethyl methacrylate and polydimethylaminoethyl acrylate.
• polydialkylaminoalkyl(meth)acrylamides such as polydimethylaminopropyl acrylamide and polydimethylaminopropyl methacrylamide
• polyacrylamides, polycationic acrylamides, polyamine sulfones, and polyallylamines examples.
• polyvinylpyrrolidone is preferred.
• a step of dispersing an oily mixture containing a monomer composition and a volatile expanding agent in an aqueous dispersion medium is carried out.
• a process is carried out in which an oily mixture containing a monomer composition and a volatile swelling agent is dispersed in an aqueous dispersion medium.
• the monomer composition and the volatile swelling agent may be added separately to the aqueous dispersion medium to prepare an oily mixture in the aqueous dispersion medium, but usually, the two are mixed in advance to form an oily mixture, which is then added to the aqueous dispersion medium.
• Examples of a method for emulsifying and dispersing the oily mixture in an aqueous dispersion medium to a predetermined particle size include a method of stirring with a homomixer (for example, manufactured by Tokushu Kika Kogyo Co., Ltd.) or a method of passing the mixture through a static dispersion device such as a line mixer or an element-type static disperser.
• a homomixer for example, manufactured by Tokushu Kika Kogyo Co., Ltd.
• a static dispersion device such as a line mixer or an element-type static disperser.
• the aqueous dispersion medium and the polymerizable mixture may be supplied separately to the static dispersing device, or a dispersion liquid that has been mixed and stirred in advance may be supplied.
• Thermal expandable microcapsules which are one embodiment of the present invention, can be produced by subjecting the dispersion obtained through the above-mentioned steps to a process of polymerizing the monomer by heating, a process of washing, and a process of drying.
• a masterbatch can be obtained by mixing the thermally expandable microcapsules of the present invention with a resin (base resin).
• a masterbatch containing the thermally expandable microcapsules of the present invention also constitutes the present invention.
• a foamable resin composition can be obtained by adding a matrix resin such as a thermoplastic resin to the thermally expandable microcapsules of the present invention.
• An ink containing the thermally expandable microcapsules and resin can also be used as a foamable ink.
• the composition containing the thermally expandable microcapsules and resin of the present invention is preferably used for applications such as adhesives, rubber chips, foam chips, flooring materials, rock consolidation materials, paints, coating materials, reinforcing fibers, composite materials, electronic components, and molding materials.
• the molding materials are preferably used for molding by injection molding, extrusion molding, blow molding, rotational molding, vacuum molding, inflation molding, calendar molding, slush molding, dip molding, foam molding, fused deposition modeling, inkjet molding, stereolithography, laser sintering, and the like.
• the resin used for the base resin is not particularly limited, and thermoplastic resins and curable resins used in ordinary foam molding can be used.
• the thermoplastic resin include polyolefins such as low-density polyethylene (LDPE) and polypropylene (PP), polyvinyl acetate, ethylene-vinyl acetate copolymer (EVA), vinyl chloride, polystyrene, thermoplastic elastomers, and ethylene-methyl methacrylate copolymer (EMMA).
• LDPE, EVA, EMMA, thermoplastic elastomers, etc. are preferred because they have low melting points and are easy to process. These may be used alone or in combination of two or more.
• the curable resin examples include epoxy resin, (meth)acrylic resin, urethane resin, phenol resin, cyanate resin, isocyanate resin, maleimide resin, benzoxazine resin, silicone resin, fluororesin, polyimide resin, and phenoxy resin.
• the curable resin preferably includes an epoxy resin. These curable resins may be used alone or in combination of two or more.
• the content of the thermally expandable microcapsules in the masterbatch pellets is not particularly limited, but a preferred lower limit is 10 parts by weight and a preferred upper limit is 90 parts by weight per 100 parts by weight of the thermoplastic resin.
• the method for producing the masterbatch pellets is not particularly limited, but examples include a method in which raw materials such as a base resin and various additives are pre-kneaded using a co-rotating twin-screw extruder or the like. The mixture is then heated to a predetermined temperature, a blowing agent such as thermally expandable microcapsules is added, and the resulting mixture is further kneaded. The resulting mixture is then cut into pellets of a desired size using a pelletizer to form the masterbatch.
• a pellet-shaped masterbatch may be produced by kneading raw materials such as the base resin and thermally expandable microcapsules using a batch kneader and then granulating them using a granulator.
• the kneading machine is not particularly limited as long as it can knead the thermally expandable microcapsules without destroying them, and examples thereof include a pressure kneader and a Banbury mixer.
• a foamed molded article can be obtained using the thermally expandable microcapsules and master batches.
• a molded article obtained using the thermally expandable microcapsules of the present invention also constitutes one aspect of the present invention.
• the thermally expandable microcapsules can be suitably used in applications requiring post-processing at high temperatures, and therefore, a foamed sheet having high quality appearance such as a concave-convex shape can be obtained.
• the thermally expandable microcapsules or a masterbatch containing the thermally expandable microcapsules are kneaded with a matrix resin, and the mixture is molded to obtain a foamed molded article. According to the present invention, it is possible to improve the gas barrier properties and durability during thermal expansion, and also to improve the expansion ratio and heat resistance.
• the molding method for the foamed molded article is not particularly limited, and examples include kneading molding, calendar molding, extrusion molding, and injection molding.
• injection molding the process is not particularly limited, and examples include the short shot method, in which a portion of the resin material is placed in a mold and foamed, and the core-back method, in which the mold is fully filled with the resin material and then opened to the desired extent for foaming.
• the present invention can provide thermally expandable microcapsules that have excellent heat resistance and gas barrier properties at high temperatures, even when using engineering plastics, without the need for special molding machines. This provides excellent foaming performance even at high temperatures. It can also provide masterbatches containing the thermally expandable microcapsules and molded articles made using the thermally expandable microcapsules.
• aqueous dispersion medium was prepared by adding 8 L of water, 5 parts by weight of colloidal silica as a dispersant, and 0.3 parts by weight of polyvinylpyrrolidone to a polymerization reaction vessel.
• An oily mixture containing the monomers and metal cation salts in the amounts shown in Tables 1 and 2 was then added to the aqueous dispersion medium and suspended to prepare a dispersion.
• the resulting dispersion was stirred and mixed using a homogenizer and placed in a nitrogen-purged pressure polymerization vessel. The reaction was carried out at 60°C for 20 hours under pressure (0.2 MPa), yielding a reaction product.
• the resulting reaction product was repeatedly filtered and washed with water, and then dried to yield thermally expandable microcapsules.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Polymers & Plastics (AREA)
• Materials Engineering (AREA)
• Engineering & Computer Science (AREA)
• Dispersion Chemistry (AREA)
• Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Processes Of Treating Macromolecular Substances (AREA)
• Manufacturing Of Micro-Capsules (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=96699973

Family Applications (1)

Country Status (3)

Citations (4)

• 2025
  • 2025-01-31 WO PCT/JP2025/003160 patent/WO2025169848A1/ja active Pending
  • 2025-01-31 JP JP2025528532A patent/JP7767689B1/ja active Active
  • 2025-02-04 TW TW114103969A patent/TW202600773A/zh unknown

Patent Citations (4)

Also Published As

Similar Documents

Legal Events