Classifications

• • 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
  • C08F290/00—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups
  • C08F290/02—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups on to polymers modified by introduction of unsaturated end groups
  • C08F290/06—Polymers provided for in subclass C08G
  • C08F290/068—Polysiloxanes
• • 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
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • 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
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/20—Manufacture of shaped structures of ion-exchange resins
  • C08J5/22—Films, membranes or diaphragms
• • 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
  • C08K3/38—Boron-containing compounds
• • 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
  • C08K9/00—Use of pretreated ingredients
  • C08K9/08—Ingredients agglomerated by treatment with a binding agent
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
  • C08L63/04—Epoxynovolacs
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
  • C08L83/04—Polysiloxanes
• • 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
  • C08J2363/00—Characterised by the use of epoxy resins; Derivatives of epoxy resins
• • 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
  • C08J2383/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen, or carbon only; Derivatives of such polymers
• • 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
  • C08J2383/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen, or carbon only; Derivatives of such polymers
  • C08J2383/04—Polysiloxanes
• • 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
  • C08J2433/00—Characterised by the use of homopolymers or 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 of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
  • C08J2433/04—Characterised by the use of homopolymers or 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 of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers esters
  • C08J2433/06—Characterised by the use of homopolymers or 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 of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers esters of esters containing only carbon, hydrogen, and oxygen, the oxygen atom being present only as part of the carboxyl radical
• • 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
  • C08K3/38—Boron-containing compounds
  • C08K2003/382—Boron-containing compounds and nitrogen
  • C08K2003/385—Binary compounds of nitrogen with boron
• • 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
  • C08K2201/00—Specific properties of additives
  • C08K2201/001—Conductive additives

Definitions

• the present invention relates to copolymers, surfactants, resin compositions, and heat dissipation sheets.
• a circuit board used in an on-board power supply system for an electric vehicle generally generates a large amount of heat due to a large voltage and current. An increase in the amount of heat generated causes circuit malfunctions and failures.
• a battery pack that supplies power to an electric motor of an electric vehicle generates heat as it is repeatedly charged and discharged. Continuing to use the battery pack at a high temperature may reduce the performance and life of the battery pack.
• heat generation problems are not limited to electric vehicles, but also occur in electronic devices.
• the heat density inside electronic devices, which are becoming more sophisticated and smaller in size, is increasing year by year.
• the heat-removing method is adopted by bringing the heat-generating part and the cooling member into contact. At this time, if there is a gap between the heat-generating member and the cooling member, the heat removal efficiency is reduced. Therefore, generally, the heat-generating portion and the cooling member are indirectly brought into contact with each other through a heat-dissipating member to remove the heat. .
• Such heat dissipating members generally contain inorganic fillers in resin. At this time, it is necessary to uniformly disperse the inorganic filler in the resin.
• inorganic fillers tend to agglomerate due to attractive forces acting between the surfaces of the inorganic fillers (for example, van der Waals force). Therefore, in order to disperse the inorganic filler in the resin, for example, it is necessary to introduce a repulsive force against the attractive force between the particles.
• Repulsive forces include, for example, electrostatic repulsive forces and steric hindrance repulsive forces.
• Methods for introducing repulsive force between particles of an inorganic filler include, for example, a method of surface-treating an inorganic filler with a silane coupling agent (see, for example, Patent Document 1).
• the silane coupling agent introduces a specific functional group to the surface of the inorganic filler, and can increase the repulsive force between the inorganic fillers.
• the present invention has been made in view of the above problems, a copolymer capable of reducing the viscosity of a resin composition containing a resin and an inorganic filler, a surfactant containing the copolymer, and the surfactant
• An object of the present invention is to provide a resin composition containing an agent and an inorganic filler, and a heat dissipation sheet containing the resin composition.
• the present inventors have made intensive studies to solve the above problems. As a result, the present inventors have found that a (meth)acrylic copolymer having a predetermined constitutional unit can solve the above problems, and have completed the present invention. That is, the present invention is as follows. [1] a (meth)acrylic monomer unit A having an anionic group; A (meth)acrylic monomer unit B having a cationic group, and a (meth)acrylic monomer unit C other than the (meth)acrylic monomer unit A and the (meth)acrylic monomer unit B, A copolymer in which the (meth)acrylic monomer unit C has a weight average molecular weight of 2,000 to 9,000.
• the content of the (meth)acrylic monomer unit A is the (meth)acrylic monomer unit A, the (meth)acrylic monomer unit B and the (meth)acrylic monomer unit 30 to 80 mol% relative to the total 100 mol% of the mer unit C
• the content of the (meth)acrylic monomer unit B is the (meth)acrylic monomer unit A, the (meth)acrylic monomer unit B and the (meth)acrylic monomer unit 0.1 to 5.0 mol% relative to the total 100 mol% of C
• the content of the (meth)acrylic monomer unit C is the (meth)acrylic monomer unit A, the (meth)acrylic monomer unit B and the (meth)acrylic monomer unit
• the copolymer according to [1] or [2] above which has a weight average molecular weight of 40,000 to 80,000.
• the (meth)acrylic monomer unit C contains at least one skeleton selected from the group consisting of an oxyalkylene skeleton, a siloxane skeleton, a hydrocarbon skeleton, and a phosphoric acid diester skeleton [1] to [ 3], the copolymer according to any one of the above.
• the anionic group contains at least one group selected from the group consisting of a carboxy group, a phosphate group and a phenolic hydroxy group. polymer.
• a resin composition comprising a resin, the surfactant according to [9] above, and an inorganic filler.
• the resin composition according to [10] above, wherein the resin is at least one resin selected from silicone resins and epoxy resins.
• the inorganic filler is boron nitride.
• a heat-dissipating sheet comprising the resin composition according to any one of [10] to [12] above.
• a copolymer capable of reducing the viscosity of a resin composition containing a resin and an inorganic filler, a surfactant containing the copolymer, and a resin composition containing the surfactant and an inorganic filler , and a heat-dissipating sheet containing the resin composition.
• the (meth)acrylic monomer units of the present invention mean both methacrylic acid monomer units and acrylic monomer units.
• the copolymer of the present embodiment comprises a (meth)acrylic monomer unit A having an anionic group, a (meth)acrylic monomer unit B having a cationic group, and the (meth)acrylic monomer unit It has a monomer unit A and a (meth)acrylic monomer unit C other than the (meth)acrylic monomer unit B, and the (meth)acrylic monomer unit C has a weight average molecular weight of 2, 000 to 9,000.
• the copolymer of the present embodiment can remarkably reduce the viscosity of a resin composition containing a resin and an inorganic filler by having the above structure. The reason is considered as follows.
• a predetermined potential difference is generated at the interface where two different substances are in contact, such as the surface of inorganic filler dispersed in resin, attracting counter ions and forming an electric double layer consisting of a stationary phase and a diffusion double layer.
• the spread of counterions on the surface of the inorganic filler is also called the thickness of the electric double layer.
• the copolymer of the present embodiment has an amphoteric anionic group and a cationic group in the molecule, thereby increasing the thickness of the electric double layer.
• one of the anionic group and the cationic group of the copolymer is arranged near the surface of the inorganic filler as a counterion.
• the other group (side ion) that does not function as a counter ion is located farther than the surface of the inorganic filler and can further form a side ion layer there.
• the term “monomer” refers to a monomer having a polymerizable unsaturated bond before polymerization
• the term “monomer unit” refers to a repeating unit that constitutes a part of the copolymer after polymerization.
• a unit derived from a given monomer is also simply referred to as “unit A”
• “(meth)acrylic monomer unit B” is simply referred to as “unit B”
• (Meth)acrylic monomer unit C” is also simply referred to as “unit C”.
• the (meth)acrylic monomer unit A is a repeating unit having an anionic group.
• anionic groups include, but are not limited to, carboxy groups, phosphoric acid groups, phenolic hydroxy groups, and sulfonic acid groups. Among these, one or more selected from the group consisting of a carboxy group, a phosphoric acid group, and a phenolic hydroxy group is preferable, and a carboxy group is more preferable. Having such a group tends to further improve the dispersibility of the inorganic filler. As a result, the copolymer of the present embodiment can sufficiently reduce the viscosity of the resin composition containing the resin and the inorganic filler.
• the unit A preferably further has an electron-withdrawing group bonded to the anionic group.
• an electron-withdrawing group is not particularly limited as long as it has the effect of stabilizing the anion of the anionic group.
• an acrylic monomer containing an electron-withdrawing substituent such as a halogen element on the ⁇ -position carbon atom of the carboxy group may be used. Having such a group tends to further improve the dispersibility of the inorganic filler.
• the copolymer of the present embodiment can sufficiently reduce the viscosity of the resin composition containing the resin and the inorganic filler.
• Unit A preferably does not have an electron-donating group bonded to an anionic group or has a group with low electron-donating property.
• Such an electron-donating group is not particularly limited as long as it has the effect of destabilizing the anion of the anionic group.
• an acrylic monomer that does not contain an electron-donating group substituent such as a methyl group on the ⁇ -position carbon atom of the carboxy group may be used.
• Such a structure tends to further improve the dispersibility of the inorganic filler.
• the copolymer of the present embodiment can sufficiently reduce the viscosity of the resin composition containing the resin and the inorganic filler.
• Examples of such (meth)acrylic monomers include, but are not limited to, acrylic acid, methacrylic acid, acid phosphoxypropyl methacrylate, acid phosphoxypolyoxyethylene glycol monomethacrylate, acid phosphoxypoly Oxypropylene glycol monomethacrylate, phosphoric acid-modified epoxy acrylate, 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 4-hydroxyphenyl acrylate, 4-hydroxyphenyl methacrylate, 2-methacryloyloxyethyl succinic acid, 2 -acrylamido-2-methylpropanesulfonic acid and the like.
• acrylic acid 2-methacryloyloxyethyl phosphate, 4-hydroxyphenyl methacrylate, and 2-acrylamido-2-methylpropanesulfonic acid are preferred, and acrylic acid is more preferred.
• the affinity of the copolymer for the inorganic filler tends to be further improved, and the dispersibility of the inorganic filler tends to be further improved.
• the copolymer of the present embodiment can sufficiently reduce the viscosity of the resin composition containing the resin and the inorganic filler.
• Unit A may be used singly or in combination of two or more.
• the (meth)acrylic monomer unit B is a repeating unit having a cationic group.
• the cationic group is not particularly limited, but for example, the cationic group is one or more selected from the group consisting of primary amino groups, secondary amino groups, tertiary amino groups, and quaternary ammonium salts. is preferred. Among these, a tertiary amino group is more preferable. Having such a group tends to further improve the dispersibility of the inorganic filler. As a result, the copolymer of the present embodiment can sufficiently reduce the viscosity of the resin composition containing the resin and the inorganic filler.
• the unit B preferably further has an electron-donating group bonded to the cationic group.
• an electron-donating group is not particularly limited as long as it has the effect of stabilizing the cation of the cationic group.
• an acrylic monomer containing an electron-donating substituent such as a methyl group on the ⁇ -position carbon atom of the amino group may be used. Having such a group tends to further improve the dispersibility of the inorganic filler.
• the copolymer of the present embodiment can sufficiently reduce the viscosity of the resin composition containing the resin and the inorganic filler.
• Unit B preferably does not have an electron-withdrawing group bonded to a cationic group, or preferably has a group with low electron-withdrawing properties.
• Such an electron-withdrawing group is not particularly limited as long as it has the effect of destabilizing the cation of the cationic group.
• an acrylic monomer that does not contain an electron-withdrawing group substituent such as a carboxyl group on the ⁇ -position carbon atom of an amino group may be used.
• Such a structure tends to further improve the dispersibility of the inorganic filler.
• the copolymer of the present embodiment can sufficiently reduce the viscosity of the resin composition containing the resin and the inorganic filler.
• Examples of such (meth)acrylic monomers include, but are not limited to, 1-aminoethyl acrylate, 1-aminopropyl acrylate, 1-aminoethyl methacrylate, 1-aminopropyl methacrylate, dimethylaminoethyl methacrylate, Diethylaminoethyl methacrylate, t-butylaminoethyl (meth)acrylate, dimethylaminoethyl methacrylate quaternary salt, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, 2,2,6,6-tetramethyl- 4-piperidyl methacrylate, dimethylaminoethyl acrylate benzyl chloride quaternary salt and the like.
• 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate and 2,2,6,6-tetramethyl-4-piperidyl methacrylate are preferred, and 1,2,2,6,6- Pentamethyl-4-piperidyl methacrylate is more preferred.
• the affinity of the copolymer for the inorganic filler tends to be further improved, and the dispersibility of the inorganic filler tends to be further improved.
• the copolymer of the present embodiment can sufficiently reduce the viscosity of the resin composition containing the resin and the inorganic filler.
• Unit B may be used singly or in combination of two or more.
• (Meth)acrylic monomer unit C) is a (meth)acrylic monomer unit other than unit A and unit B, and is a (meth)acrylic monomer unit containing no cationic or anionic group in the molecule. Quantity.
• the (meth)acrylic monomer C is the resin used in the resin composition.
• a skeleton with high affinity or compatibility with Such a skeleton is not particularly limited, but for example, an amphipathic skeleton such as an oxyalkylene skeleton, a siloxane skeleton such as dimethylsiloxane, a hydrophobic skeleton such as a hydrocarbon skeleton such as alkyl or aryl, or a phosphate diester skeleton. and other hydrophilic skeletons.
• an oxyalkylene skeleton, a siloxane skeleton, and a hydrocarbon skeleton are preferred, a siloxane skeleton and a hydrocarbon skeleton are more preferred, and a siloxane skeleton is even more preferred.
• the compatibility between the copolymer of the present embodiment and the resin tends to be further improved, and the dispersibility of the inorganic filler in the resin composition tends to be further improved.
• the copolymer of the present embodiment can sufficiently reduce the viscosity of the resin composition containing the resin and the inorganic filler.
• Examples of such (meth)acrylic monomers include, but are not limited to, ethoxycarbonylmethyl (meth)acrylate, phenol ethylene oxide-modified (meth)acrylate, phenol (ethylene oxide 2 mol modified) (meth)acrylate , phenol (modified by 4 moles of ethylene oxide) (meth)acrylate, paracumylphenol ethylene oxide-modified (meth)acrylate, nonylphenol ethylene oxide-modified (meth)acrylate, nonylphenol (modified by 4 moles of ethylene oxide) (meth)acrylate, nonylphenol (ethylene oxide 8 mol modified) (meth) acrylate, nonylphenol (propylene oxide 2.5 mol modified) acrylate, 2-ethylhexyl carbitol (meth) acrylate, ethylene oxide modified phthalic acid (meth) acrylate, ethylene oxide modified succinic acid (meth) (meth)acrylic monomers having an oxyalkylene skeleton such as
• (meth) Acrylic monomer 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (Meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate and other hydroxyl group-containing (meth)acrylic monomers; N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide , N-isopropyl (meth)acrylamide, diacetone (meth)acrylamide, or (meth)acrylic monomer having an amide bond such as acryloylmorpholine; ⁇ -butyl- ⁇ -(3-methacryloxypropyl)polydimethylsiloxane (Meth) acrylic monomers having a siloxane skeleton such as; (meth) acrylic monomers having a phosphoric acid diester skeleton such
• Unit C may be used singly or in combination of two or more.
• (meth)acrylic monomers having a siloxane skeleton such as ⁇ -butyl- ⁇ -(3-methacryloxypropyl)polydimethylsiloxane are preferred.
• the (meth)acrylic monomer C has a weight average molecular weight of 2,000 to 9,000. If the weight-average molecular weight of the (meth)acrylic monomer C is less than 2,000, the affinity of the copolymer to the resin may be insufficient, resulting in poor dispersibility of the inorganic filler. As a result, it may be difficult to sufficiently reduce the viscosity of the resin composition containing the resin and the inorganic filler. Further, when the weight average molecular weight of the (meth)acrylic monomer C is more than 9,000, the viscosity of the composition obtained by mixing the copolymer with the resin may increase.
• the weight average molecular weight of the (meth)acrylic monomer C is preferably 2,500 to 7,000, more preferably 3,000 to 6,000, and still more preferably 3,500 to 5,500.
• the weight average molecular weight of the (meth)acrylic monomer C is the weight average molecular weight of the (meth)acrylic monomer unit C.
• the content of unit A is preferably 30 to 80 mol%, more preferably 40 to 65 mol%, relative to the total 100 mol% of unit A, unit B, and unit C.
• the content of the unit A is 30 mol % or more, the affinity of the copolymer for the resin tends to be further improved, and the dispersibility of the inorganic filler tends to be further improved.
• the copolymer of the present embodiment can sufficiently reduce the viscosity of the resin composition containing the resin and the inorganic filler.
• the content of the unit A is 80 mol % or less, the copolymer can contain the unit B and the unit C in sufficient content.
• the content of unit B is preferably 0.1 to 5 mol%, more preferably 0.5 to 3 mol%, relative to the total 100 mol% of unit A, unit B, and unit C. preferable.
• the content of the unit B is preferably 0.1 to 5 mol%, more preferably 0.5 to 3 mol%, relative to the total 100 mol% of unit A, unit B, and unit C. preferable.
• the total content of unit A and unit B is preferably 30.1 to 85 mol%, preferably 35 to 75 mol%, relative to the total 100 mol% of unit A, unit B, and unit C. is more preferred.
• the total content of the units A and B is 30.1 mol % or more, the affinity of the copolymer to the resin is further improved, and the dispersibility of the inorganic filler tends to be further improved.
• the unit C can be contained in the copolymer in a sufficient content.
• the molar ratio of unit A to unit B is preferably 6-800, more preferably 20-400.
• the affinity of the copolymer to the resin tends to be further improved, and the dispersibility of the inorganic filler tends to be further improved.
• the content of unit C is preferably 20 to 70 mol%, more preferably 30 to 55 mol%, relative to the total 100 mol% of unit A, unit B, and unit C.
• the content of unit C is preferably 20 to 70 mol%, more preferably 30 to 55 mol%, relative to the total 100 mol% of unit A, unit B, and unit C.
• the weight average molecular weight of the copolymer is preferably 40,000 to 80,000, more preferably 50,000 to 70,000.
• the weight-average molecular weight of the copolymer is 40,000 or more, the inorganic filler is less likely to aggregate due to the steric hindrance repulsive force of the copolymer, and the dispersibility of the inorganic filler in the resin composition is further improved.
• the weight average molecular weight of the copolymer is 80,000 or less, it becomes easier to dissolve the copolymer in the resin or solvent.
• the weight average molecular weight can be determined by GPC (gel permeation chromatography).
• the copolymer of this embodiment is preferably a copolymer represented by the following general formula (1).
• the copolymer represented by formula (1) may be a random copolymer or a block copolymer.
• the unit A of the copolymer represented by the following general formula (1) is derived from acrylic acid, and the anionic group is a carboxy group.
• the unit B of the copolymer represented by the following general formula (1) is derived from 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, and the cationic group is a tertiary amino group. be.
• the unit C of the copolymer represented by the following general formula (1) is derived from ⁇ -butyl- ⁇ -(3-methacryloxypropyl)polydimethylsiloxane and has a siloxane skeleton.
• s is, when the weight average molecular weight of the copolymer is 40,000 to 80,000, the content of unit A is 30 to 30 to 100 mol% of the total of unit A, unit B, and unit C t is an integer such that it is 80 mol %, and t is the total content of unit A, unit B, and unit C when the weight average molecular weight of the copolymer is 40,000 to 80,000 is an integer such that it is 20 to 70 mol% with respect to 100 mol%, u is when the weight average molecular weight of the copolymer is 40,000 to 80,000, the content of unit B is unit A, It is an integer such that it is 0.1 to 5.0 mol % with respect to 100 mol % of the total of units B and C. Further, v is an integer such that the weight average molecular weight of unit C is 2,000 to 9,000.
• the copolymer of the present invention has good affinity with resins and is easily adsorbed to inorganic fillers, so it is suitable for surface treatment of inorganic fillers contained in resin compositions used in heat-dissipating sheets.
• the copolymer of the present invention since the copolymer of the present invention has a relatively large weight-average molecular weight, it has many anchor moieties that adsorb to the inorganic filler. It has good adsorption properties. Therefore, the copolymer of the present invention is more suitable for surface treatment of inorganic fillers such as boron nitride having stable surfaces. Surface treatment of the inorganic filler may be performed prior to mixing the inorganic filler with the resin. Further, when the inorganic filler is mixed with the resin, the copolymer may be mixed together, and the inorganic filler may be surface-treated when the inorganic filler is mixed with the resin.
• the method for producing the copolymer of the present embodiment is not particularly limited, and a known polymerization method for (meth)acrylic monomers can be used.
• the polymerization method include radical polymerization and anionic polymerization. Among these, radical polymerization is preferred.
• the thermal polymerization initiator used for radical polymerization is not particularly limited, and examples thereof include azo compounds such as azobisisobutyronitrile; organic peroxides such as benzoyl peroxide, tert-butyl hydroperoxide and di-tert-butyl peroxide; things, etc.
• the photopolymerization initiator used for radical polymerization is not particularly limited, but a benzoin derivative can be used.
• known polymerization initiators used for living radical polymerization such as ATRP and RAFT can also be used.
• the polymerization conditions are not particularly limited, and can be appropriately adjusted depending on the initiator used, the boiling point of the solvent, and the type of other monomers.
• the order of addition of the monomers is not particularly limited.
• the monomers may be mixed to initiate polymerization.
• the monomers may be added sequentially to the polymerization system.
• the surfactant of the present embodiment contains the above copolymer, and if necessary, may contain a solvent and other optional additives. Alternatively, the above copolymer may be used alone as a surfactant and added to the mixture of the inorganic filler and the resin.
• a surfactant is used for the purpose of uniformly dispersing the inorganic filler in the resin.
• the surfactant of the present embodiment can disperse the inorganic filler by the electrostatic repulsive force of the copolymer and prevent the reaggregation of the inorganic fillers.
• the above copolymer further has an effect of improving dispersibility due to steric hindrance repulsive force.
• the resin is not particularly limited, for example, those contained in the resin composition described later can be exemplified.
• the resin composition of the present embodiment contains a resin, the above copolymer, and an inorganic filler, and may optionally contain a solvent and other optional additives.
• an inorganic filler is dispersed in a resin using a copolymer.
• the content of the copolymer is preferably 0.01 to 15% by volume, more preferably 0.1 to 10% by volume, with respect to the total 100% by volume of the resin, inorganic filler and copolymer content. is more preferable.
• the content of the copolymer is 0.01% by volume or more, the dispersibility of the inorganic filler tends to be further improved.
• the content of the copolymer is 15% by volume or less, the thermal conductivity of the resin composition tends to be further improved.
• the inorganic filler is not particularly limited, but examples include inorganic fillers having electrical and/or thermal conductivity.
• examples of such inorganic fillers include one or more selected from boron nitride powder, aluminum nitride powder, aluminum oxide powder, silicon nitride powder, silicon oxide powder, magnesium oxide powder, metal aluminum powder, and zinc oxide powder. are mentioned. Among these, boron nitride powder and aluminum oxide powder are preferred, and boron nitride powder is more preferred. The use of such an inorganic filler tends to further improve the electrical conductivity and/or thermal conductivity of the resin composition.
• the average particle size of the inorganic filler is preferably 0.4-120 ⁇ m, more preferably 5-80 ⁇ m.
• the average particle size of the inorganic filler is preferably 0.4-120 ⁇ m, more preferably 5-80 ⁇ m.
• the inorganic filler may be a mixture of inorganic fillers having multiple average particle sizes. Compared to the case of containing only an inorganic filler having a single average particle size, by using an inorganic filler having a smaller average particle size, the gaps between the large-diameter inorganic fillers are filled with small-diameter inorganic fillers. be able to. Therefore, by using a mixture of inorganic fillers having a plurality of average particle sizes, it becomes possible to fill the resin composition with the inorganic filler at a higher level.
• the content of the inorganic filler is preferably 20 to 90% by volume, more preferably 25 to 85% by volume, based on the total 100% by volume of the resin, inorganic filler and copolymer content.
• the content of the inorganic filler is 20% by volume or more, electrical conductivity and/or thermal conductivity tend to be further improved.
• the content of the inorganic filler is 90% by volume or less, the dispersibility of the inorganic filler in the resin composition is improved.
• the resin is not particularly limited, but examples include thermosetting resins such as silicone resins, epoxy resins, phenol resins, cyanate resins, melamine resins, urea resins, thermosetting polyimides, and unsaturated polyester resins; acrylic resins and polyolefin resins. , polycarbonate resins, polyester resins, vinyl chloride resins, urethane resins, polyamide resins, and ABS (acrylonitrile-butadiene-styrene) resins. Among these, one or more resins selected from the group consisting of silicone-based resins and epoxy-based resins are preferable.
• Optional additives are not particularly limited, but include, for example, silane coupling agents, antioxidants, and metal corrosion inhibitors.
• the resin composition of the present embodiment can be produced by kneading with a planetary stirrer, a universal mixer, a kneader, a hybrid mixer, or the like.
• the heat-dissipating sheet of this embodiment contains the resin composition of the present invention. Thereby, the thermal conductivity of the heat dissipation sheet can be increased.
• the heat dissipation member of this embodiment is arranged, for example, between the electronic component and the heat sink. Thereby, it is possible to suppress the generation of a gap between the electronic component and the heat sink. As a result, heat generated by the electronic component can be efficiently conducted to the heat sink.
• the electronic parts are not particularly limited, but include, for example, motors, battery packs, circuit boards used in in-vehicle power supply systems, power transistors, and heat-generating electronic parts such as microprocessors. Among these, electronic parts used in vehicle-mounted power supply systems are preferable.
• the heat sink is not particularly limited as long as it is a component configured for the purpose of heat radiation or heat absorption.
• Copolymer 1 The copolymer was prepared by the following method. First, acrylic acid: 48.4 mol%, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate: 1.6 mol%, ⁇ -butyl- ⁇ -(3- 100 parts by mass of a (meth)acrylic monomer consisting of 50.0 mol % of methacryloxypropyl)polydimethylsiloxane (weight average molecular weight: 5,000) was added.
• acrylic acid 48.4 mol%
• 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate 1.6 mol%
• ⁇ -butyl- ⁇ -(3- 100 parts by mass of a (meth)acrylic monomer consisting of 50.0 mol % of methacryloxypropyl)polydimethylsiloxane (weight average molecular weight: 5,000) was added.
• the polymerization rate for 100% of the charged amount of monomer was 98% or more when analyzed by gas chromatography analysis. From this, it was estimated that the ratio of each monomer unit in the copolymer was approximately the same as the charging ratio of the monomers.
• the weight average molecular weight of the obtained copolymer 1 was obtained as a weight average molecular weight in terms of standard polystyrene using GPC (gel permeation chromatography) method.
• the measurement conditions are as follows. High-speed GPC device: "HLC-8020" manufactured by Tosoh Corporation Column: Tosoh Corporation "TSK guardcolumn MP (x L)" 6.0 mm ID ⁇ 4.0 cm 1 piece, and Tosoh Corporation "TSK-GELMULTIPOREHXL-M” 7.8 mm ID ⁇ 30.0 cm (theoretical plate number 16,000 plates ) 2, 3 in total (32,000 theoretical plates in total) Developing solvent: Tetrahydrofuran Detector: RI (differential refractometer)
• ⁇ -butyl- ⁇ -(3-methacrylate Copolymer 2 was obtained by performing radical polymerization in the same manner as for Copolymer 1, except that the proportion of (roxypropyl)polydimethylsiloxane was changed from 50.0 mol % to 30.0 mol %.
• the polymerization rate of the obtained copolymer 2 was 98% or more, and the ratio of each monomer unit in the copolymer was estimated to be approximately the same as the charging ratio of the monomers.
• the weight average molecular weight was determined in the same manner as described above. Since the weight average molecular weight of ⁇ -butyl- ⁇ -(3-methacryloxypropyl)polydimethylsiloxane was 10,000, the weight average molecular weight of unit C is 10,000.
• Copolymer 3 is a high-molecular amine compound ("Esleem AD-374M” manufactured by NOF Corporation).
• Copolymer 4 is a polymeric polycarboxylic acid (“Malialim AAB-0851” manufactured by NOF Corporation).
• composition of the monomers shown in Table 1 is expressed in molar ratio (%).
• the molar ratio was calculated from the added amount and molecular weight of each monomer. Also, the molar ratio of ⁇ -butyl- ⁇ -(3-methacryloxypropyl)polydimethylsiloxane was calculated based on the weight average molecular weight.
• compositions and weight-average molecular weights of copolymers 1 and 2 synthesized as described above are shown in Table 1 below.
• the average particle size of the inorganic filler was measured using a "laser diffraction particle size distribution measuring device SALD-20" manufactured by Shimadzu Corporation.
• An evaluation sample was obtained by adding 50 ml of pure water and 5 g of an inorganic filler to be measured to a glass beaker, stirring with a spatula, and then performing dispersion treatment with an ultrasonic cleaner for 10 minutes.
• the dispersed liquid of the inorganic filler subjected to the dispersion treatment was added drop by drop to the sampler section of the device using a dropper, and the measurement was performed when the absorbance was stabilized. D50 (median diameter) was adopted as the average particle size.
• Resin compositions 2 to 16 were prepared in the same manner as resin composition 1, except that the components of the compositions shown in Tables 2 to 5 were used. Evaluation of the obtained resin compositions 2 to 16 is shown. 2 to 5.
• a resin composition sheet was produced by molding the resin composition into a sheet by a doctor blade method. Then, the resin composition sheet was heated and pressed under vacuum under the conditions of a heating temperature of 120° C., a pressure of 5 MPa, and a heating and pressing time of 30 minutes to prepare a heat dissipation sheet.
• Thermo Scientific's rotary rheometer MARS III uses a 35 mm ⁇ parallel plate as an upper jig, and a 35 mm ⁇ lower plate whose temperature can be controlled with a Peltier element. It was compressed to 1 mm, the protruding portion was scraped off, and the measurement was performed at 25°C. The viscosity at a shear rate of 1 to 10 s -1 was measured, and the viscosity at a shear rate of 10 s -1 was used for evaluation.
• a (meth)acrylic monomer unit A having an anionic group a (meth)acrylic monomer unit B having a cationic group, (Meth) acrylic monomer unit A and (meth) acrylic monomer unit C other than (meth) acrylic monomer unit B, weight of (meth) acrylic monomer unit C Since a copolymer having an average molecular weight of 2,000 to 9,000 was used, the viscosity could be significantly reduced as compared with the comparative examples. On the other hand, in Comparative Resin Compositions 2, 6, 10 and 14, the weight average molecular weight of the (meth)acrylic monomer unit C was greater than 9,000, so the viscosity could not be significantly reduced. rice field.
• the copolymers used in the resin compositions 3, 4, 7, 8, 11, 12, 15 and 16 of Comparative Examples are a (meth)acrylic monomer unit A having an anionic group and a cationic A (meth)acrylic monomer unit B having a group, and a (meth)acrylic monomer unit C other than the (meth)acrylic monomer unit A and the (meth)acrylic monomer unit B

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