Liquid composition and sheet

Abstract

To provide a liquid composition having excellent liquid properties which comprises a powder of a tetrafluoroethylene based polymer, a polymerizable compound and an inorganic filler in which the content of forming components for moldings thereof is substantially high.SOLUTION: There is provided a liquid composition which comprises a powder of a tetrafluoroethylene based polymer having a hydroxyl group-containing group or a carbonyl group-containing group and a melting temperature of 200 to 320°C, a compound having two or more epoxy groups or (meth)acryloyloxy groups, a curing agent and an inorganic filler, wherein the content of the tetrafluoroethylene based polymer, the compound, the curing agent and the inorganic filler in total is 60 mass% or more.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a liquid composition and a sheet. [Background technology]

[0002] A dispersion containing a powder of tetrafluoroethylene polymer has been proposed as a coating agent for forming molded articles having the physical properties of tetrafluoroethylene polymer (electrical properties such as low dielectric constant and low dielectric tangent, mold releasability, water and oil repellency, chemical resistance, weather resistance, etc.) (see Patent Document 1). Moreover, in recent years, from the viewpoint of improving the electrical properties (low dielectric constant, low dielectric loss tangent) of electronic components such as printed wiring boards, there has been active research into blending tetrafluoroethylene polymer powders into materials for electronic components.

[0003] Patent Document 2 proposes blending tetrafluoroethylene polymer powder into interlayer insulating materials and solder resist materials for electronic components. Patent Document 3 proposes blending tetrafluoroethylene polymer powder into a sheet material that is laminated onto a conductor layer in the manufacture of multilayer printed wiring boards by a method (build-up method) in which electrical insulating layers and conductor layers are alternately stacked. Patent Document 4 proposes blending a tetrafluoroethylene polymer powder into a filling material (hole-filling material) for filling through holes in a multilayer printed wiring board having through holes spanning multiple layers so that another conductor layer can be placed over the through holes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2016 / 159102 Brochure [Patent Document 2] JP 2020-055920 A [Patent Document 3] JP 2019-167426 A [Patent Document 4] JP 2016-100546 A Summary of the Invention [Problem to be solved by the invention]

[0005] Tetrafluoroethylene polymers have a very low affinity with other components due to their low surface tension. Therefore, a large amount of solvent is often used to prepare a liquid composition in which the powder is dispersed. This limits the thickness of the molded product that can be formed from such a liquid composition in one coating, and limits the material and shape of the substrate to be coated. Furthermore, in order to ensure liquid properties such as dispersibility and flowability, it is often necessary to separately blend a large amount of various additives into the liquid composition, which makes the preparation complicated, and there is also the problem that the physical properties of the molded product, such as heat resistance, electrical properties, adhesiveness, and surface smoothness, are deteriorated.

[0006] The present inventors have found that these problems become prominent when a tetrafluoroethylene-based polymer powder is dispersed in a liquid composition containing a polymerizable compound and an inorganic filler. An object of the present invention is to provide a liquid composition which contains a tetrafluoroethylene polymer powder, a polymerizable compound, and an inorganic filler, has a substantially high content of these components for forming a molded product, and has excellent liquid physical properties. [Means for solving the problem]

[0007] The present invention has the following aspects. <1> A liquid composition comprising a powder of a tetrafluoroethylene polymer having a hydroxyl group-containing group or a carbonyl group-containing group and a melting temperature of 200 to 320°C, a compound having two or more epoxy groups or (meth)acryloyloxy groups, a curing agent, and an inorganic filler, wherein the total content of the tetrafluoroethylene polymer, the compound, the curing agent, and the inorganic filler is 60 mass% or more. <2> The composition further contains an alkali-soluble polymer, and the total content of the tetrafluoroethylene-based polymer, the compound, the curing agent, the inorganic filler, and the alkali-soluble polymer is more than 60 mass%. <1> A liquid composition comprising: <3> The viscosity is 100,000 mPa·s or less. <1> or <2> A liquid composition comprising: <4> The composition does not contain a solvent, or contains a solvent and the content of the solvent is 40% by mass or less. <1> ~ <3> Any of the liquid compositions. <5> The tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer that contains a unit based on perfluoro(alkyl vinyl ether) and has a carbonyl group-containing group. <1> ~ <4> Any of the liquid compositions. <6> The powder has an average particle size of 0.1 to 6 μm. <1> ~ <5> Any of the liquid compositions. <7> The inorganic filler is a filler containing silicon oxide. <1> ~ <6> Any of the liquid compositions. <8> The inorganic filler has an average particle size of 0.1 to 25 μm. <1> ~ <7> Any of the liquid compositions. <9> The compound is a liquid compound having two or more epoxy groups. <1> ~ <8> Any of the liquid compositions. <10> The compound is a liquid compound having two or more epoxy groups and a tertiary amine structure. <1> ~ <9> Any of the liquid compositions. <11> The compound is a liquid compound having two or more epoxy groups of at least one type selected from the group consisting of bisphenol type epoxy resins, phenol novolac type epoxy resins, catechol type epoxy resins, glycidylamine type epoxy resins, aminophenol type epoxy resins, and alicyclic epoxy resins. <1> ~ <9> Any of the liquid compositions. <12> The curing agent is an amine, an imidazole, a phenol, or an acid anhydride; <1> ~ <11> Any of the liquid compositions. <13> The content of the tetrafluoroethylene-based polymer is 30% by mass or less, the content of the compound is 30% by mass or less, the content of the curing agent is 15% by mass or less, and the content of the inorganic filler is more than 30% by mass. <1> ~ <12> Any of the liquid compositions. <14> A filling material used to fill through holes or recesses in multilayer printed wiring boards. <1> ~ <13> Any of the liquid compositions. <15> <1> ~ <13> A sheet having a layer formed from any one of the liquid compositions above. Effect of the Invention

[0008] The liquid composition of the present invention has excellent handling properties, and can easily form any molded product having the physical properties of a tetrafluoroethylene-based polymer and high surface smoothness and adhesiveness. For example, by curing the liquid composition of the present invention, a cured product can be formed that has the physical properties of a tetrafluoroethylene-based polymer, has a volume change rate that is easy to control, has few voids, and is capable of forming a cured product. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The following terms have the following meanings. "Average particle size (D50)" is the cumulative 50% volume diameter of a powder of interest (powder or inorganic filler) determined by laser diffraction / scattering. In other words, the particle size distribution of the object is measured by laser diffraction / scattering, the total volume of the particle group of the object is set as 100%, and a cumulative curve is calculated. The average particle size (D50) is the particle size at the point on the cumulative curve where the cumulative volume is 50%. "D90" is the volume-based cumulative 90% diameter of an object, measured in a similar manner. The term "melting temperature (melting point)" refers to the temperature corresponding to the maximum value of the melting peak of a polymer as measured by differential scanning calorimetry (DSC). "Glass transition temperature (Tg)" is a value measured by analyzing a polymer, a cured product, or an elastomer using a dynamic mechanical analysis (DMA) method. The "viscosity" is a value determined by measuring the liquid composition using a Brookfield viscometer at 25° C. and a rotation speed of 30 rpm. The measurement is repeated three times, and the average value of the three measured values ​​is calculated. The "thixotropy ratio" is the viscosity η of a liquid composition measured at a rotation speed of 30 rpm. 1 The viscosity η is calculated by measuring the viscosity at a rotation speed of 60 rpm. 2 The value calculated by dividing by (η 1 / η 2 ). The "unit" in a polymer may be an atomic group formed directly from a monomer, or may be an atomic group in which a part of the structure is converted by treating the obtained polymer with a predetermined method. A unit based on monomer A contained in a polymer is also simply referred to as a "monomer A unit".

[0010] The liquid composition of the present invention (hereinafter also referred to as "the composition") contains a powder (hereinafter also referred to as "F powder") of a tetrafluoroethylene-based polymer (hereinafter also referred to as "F polymer") having a hydroxyl group-containing group or a carbonyl group-containing group and having a melting temperature of 200 to 320°C, a compound having two or more epoxy groups or (meth)acryloyloxy groups (hereinafter also referred to as "curable compound"), a curing agent, and an inorganic filler. The total content of the F polymer, the curable compound, the curing agent and the inorganic filler in the present composition is 60 mass % or more.

[0011] This composition has high dispersion stability and fluidity and is easy to handle, even though it contains a substantial amount of forming components (F polymer, curable compound, curing agent, and inorganic filler) of the molded product. When this composition contains an alkali-soluble polymer, which will be described later, this is also included in the forming components. In addition, the molded product obtained from this composition has few voids and can highly express the physical properties of the F polymer. The reason for this is not necessarily clear, but is thought to be as follows.

[0012] The F polymer having an oxygen-containing polar group (a hydroxyl-containing group or a carbonyl-containing group) has a high surface energy compared to other tetrafluoroethylene-based polymers such as polytetrafluoroethylene. Therefore, not only is the F powder itself excellent in dispersibility, but it also interacts highly with other components forming molded products such as curable compounds, making it easy to stabilize. In addition, since the melting temperature of the F polymer is 200 to 320°C, it is considered that the melting or deformation of the F powder is suppressed immediately before the use of the composition, for example, even at the stage where the curable compound reacts by heating, and the liquid properties of the composition are easily maintained.

[0013] In addition, since the curable compound is cured under such conditions to form a molded product, the molded product formed from this composition contains each component of the molded product densely and homogeneously, has few voids, and is considered to have high F polymer properties. Furthermore, since the F polymer has an oxygen-containing polar group and a high melting temperature, it forms microspherulites in the molded product, which is considered to improve the surface smoothness and adhesiveness of the molded product.

[0014] The viscosity of the composition is preferably 100,000 mPa·s or less, more preferably 50,000 mPa·s or less. The lower limit is preferably 100 mPa·s, more preferably 1,000 mPa·s. The composition being liquid means that the composition is liquid, semi-solid, or pasty at 25°C, in other words, in a state having fluidity at 25°C.

[0015] The F powder in the present invention preferably has a D50 of 6 μm or less, more preferably 3 μm or less. The D50 of the F powder is preferably 0.01 μm or more, more preferably 0.1 μm or more. The D90 of the F powder is preferably 10 μm or less, more preferably 8 μm or less. In this range of D50 and D90, the flowability and dispersibility of the F powder are good, and the electrical properties (low dielectric constant, low dielectric loss tangent, etc.) of the molded product are more likely to be improved. The F powder preferably contains an F polymer as a main component. The content of the F polymer in the F powder is preferably 80% by mass or more, and more preferably 100% by mass.

[0016] The surface of the F powder may be coated with an inorganic substance. Specific examples of such inorganic substances include inorganic fillers and silane coupling agents, more specifically, silica fillers, silane coupling agents (3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, etc.), and reaction products thereof. In this case, the fluidity of the composition is increased, and the handling property is further improved.

[0017] The F polymer in the present invention contains units based on tetrafluoroethylene (TFE) (TFE units) and has a hydroxyl group-containing group or a carbonyl group-containing group, and has a melting temperature of 200 to 320°C. The F polymer is preferably a polymer (PFA) containing TFE units and units based on perfluoro(alkyl vinyl ether) (PAVE) (PAVE units), or a polymer (FEP) containing TFE and units based on hexafluoropropylene, and PFA is more preferred from the viewpoint of having a sufficiently high melting temperature and being easily capable of forming microspherulites. PAVE is CF 2 =CFOCF 3 , C.F. 2 =CFOCF 2 CF 3 or CF 2 =CFOCF 2 CF 2 CF 3 (PPVE) is preferred, with PPVE being more preferred.

[0018] The hydroxyl group-containing group or carbonyl group-containing group of the F polymer may be contained in a unit in the F polymer, or may be contained in a terminal group of the main chain of the polymer. Examples of the latter embodiment include an F polymer having a hydroxyl group-containing group or a carbonyl group-containing group as a terminal group derived from a polymerization initiator, a chain transfer agent, etc., and an F polymer having a hydroxyl group-containing group or a carbonyl group-containing group obtained by subjecting an F polymer to plasma treatment or ionizing radiation treatment. The F polymer preferably has a carbonyl group-containing group from the viewpoint of improving the dispersibility of the present composition and the physical properties of the molded article formed therefrom.

[0019] The hydroxyl group-containing group is preferably a group containing an alcoholic hydroxyl group, and -CF 2 CH 2 OH or -C(CF 3 ) 2 OH is more preferred. The carbonyl group-containing group is a group that contains a carbonyl group (>C(O)), and includes a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, a carbamate group (-OC(O)NH 2 ), an acid anhydride residue (-C(O)OC(O)-), an imide residue (-C(O)NHC(O)- etc.) or a carbonate group (-OC(O)O-), and an acid anhydride residue is more preferred.

[0020] The F polymer is preferably a polymer containing TFE units and PAVE units and having a hydroxyl group-containing group or a carbonyl group-containing group. In this case, the polymer is more likely to form microcrystals, and the denseness, adhesiveness, and surface smoothness of the molded product are more likely to be improved. The F polymer is preferably a polymer containing TFE units, PAVE units, and units based on a monomer having a hydroxyl group-containing group or a carbonyl group-containing group. This polymer preferably contains 90 to 99 mol% of TFE units, 0.5 to 9.97 mol% of PAVE units, and 0.01 to 3 mol% of units based on a monomer having a hydroxyl group-containing group or a carbonyl group-containing group, based on the total units. Moreover, the monomer having a hydroxyl group-containing group or a carbonyl group-containing group is preferably itaconic anhydride, citraconic anhydride, or 5-norbornene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH"). Specific examples of such polymers include those described in WO 2018 / 16644.

[0021] The curable compound in the present invention is preferably a compound having two or more epoxy groups (hereinafter also referred to as "epoxy compound"), and more preferably a liquid epoxy compound. The term "liquid epoxy compound" means that the epoxy compound is in a liquid, semi-solid or paste state at 25°C, in other words, in a state having fluidity at 25°C. The curable compounds may be used alone or in combination of two or more. A liquid curable compound and a non-liquid curable compound may be used in combination.

[0022] A preferred embodiment of the epoxy compound is a liquid epoxy compound having two or more epoxy groups and a tertiary amine structure. Such an epoxy compound is likely to interact with the F powder, and is likely to further improve the dispersibility of the composition. Specific examples of such epoxy compounds include tetraglycidylaminodiphenylmethane, tetraglycidylmeta-xylylenediamine, triglycidylpara-aminophenol, diglycidylaniline, and diglycidylorthotoluidine. A preferred embodiment of the epoxy compound is a liquid epoxy compound having two or more epoxy groups and at least one type selected from the group consisting of bisphenol-type epoxy resins, phenol novolac-type epoxy resins, catechol-type epoxy resins, glycidylamine-type epoxy resins, aminophenol-type epoxy resins, and alicyclic epoxy resins.

[0023] Specific examples of suitable epoxy compounds include "Epicron 860", "Epicron 900-IM", "Epicron HP-4032", "Epicron N-740", "Epicron EXA-4816" and "Epicron EXA-4822" (manufactured by DIC Corporation), "Araldite AER280" (manufactured by Asahi Chiba Corporation), "Epotohto YD-134" (manufactured by Tohto Kasei Co., Ltd.), "jER834" and "jER872" (manufactured by Mitsubishi Chemical Corporation), "ELA-134" (manufactured by Sumitomo Chemical Co., Ltd.), "Epon828" and "Epon807" (manufactured by HEXION Corporation), "ELM-100" (manufactured by Sumitomo Chemical Co., Ltd.), and "RE-305S" (manufactured by Nippon Kayaku Co., Ltd.).

[0024] Specific examples of compounds having two or more (meth)acryloyloxy groups include acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, glycol (meth)acrylates, triol (meth)acrylates, tetraol (meth)acrylates, urethane (meth)acrylates, and epoxy (meth)acrylates.

[0025] The curing agent in the present invention is an agent for reacting a curable compound or F polymer to cure the composition and form a molded article, and is preferably an amine, imidazole, phenol or acid anhydride, and more preferably an amine or imidazole from the viewpoints of the stability of the composition and the adhesiveness and electrical properties of the molded article formed therefrom. The curing agent may be used alone or in combination of two or more kinds. It is preferable to select a curing agent so that the curing initiation temperature of the present composition is 60 to 100° C. The “curing initiation temperature” is the temperature that indicates the first change point when the present composition is heated, as confirmed by differential scanning calorimetry (DSC).

[0026] As the amine, aliphatic polyamines (alkylenediamines, polyalkylene polyamines, aliphatic polyamines having aromatic rings, etc.), their adduct compounds, alicyclic polyamines (isophorone diamine, 1,3-bis(aminomethyl)cyclohexane, bis(4-aminocyclohexyl)methane, norbornene diamine, 1,2-diaminocyclohexane, laromine, etc.), or their adduct compounds are preferred. The former adduct compounds include the addition reaction products of aliphatic polyamines and phenyl glycidyl ether, tolyl glycidyl ether, or alkyl glycidyl ether. The latter adduct compounds include the addition reaction products of alicyclic polyamines and n-butyl glycidyl ether or bisphenol A diglycidyl ether. Specific examples of amines include the "Fujicure FXR" series or the "Fujicure FXR" series (both manufactured by Fuji Chemical Industry Co., Ltd.), the "Ancamin" series or the "Sunmide" series (both manufactured by Air Products J.K. Co., Ltd.), jER Cure 113 (manufactured by Mitsubishi Chemical Corporation), and Laromin C-260 (manufactured by BASF).

[0027] As the imidazole, 2-methylimidazole, 4-methyl-2-ethylimidazole, 2-phenylimidazole, 4-methyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, an azine compound of imidazole, an isocyanurate salt of imidazole, a hydroxymethyl imidazole body, or an adduct compound thereof (such as a reaction product of an epoxy resin and imidazole; Curesol P-0505 (manufactured by Shikoku Chemical Industry Co., Ltd.)) is preferable.

[0028] As the phenol, hydroquinone, resorcinol or bisphenol A is preferred. The acid anhydride is preferably phthalic anhydride, hexahydrophthalic anhydride, methylnadic anhydride, or benzophenonetetracarboxylic acid. When the curable compound is a compound having two or more (meth)acryloyloxy groups, the curing agent may be a polymerization initiator. Examples of the polymerization initiator include alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzophenone-based photopolymerization initiators, 2,2'-azobisisobutyronitrile, and benzoyl peroxide.

[0029] The inorganic filler in the present composition is preferably a filler containing a nitride or a filler containing an inorganic oxide, more preferably a boron nitride filler, a beryllia filler (a beryllium oxide filler), a filler containing silicon oxide (such as a silica filler, a wollastonite filler, or a talc filler), or a metal oxide (such as cerium oxide, aluminum oxide, magnesium oxide, zinc oxide, or titanium oxide) filler, and even more preferably a silica filler. When the inorganic filler is a silica filler, the silica content in the inorganic filler is preferably 50% by mass or more, more preferably 75% by mass, and is preferably 100% by mass or less, more preferably 90% by mass or less.

[0030] The inorganic filler is preferably surface-treated with polyhydric alcohol (trimethylolethane, pentaerythritol, propylene glycol, etc.), saturated fatty acid (stearic acid, lauric acid, etc.), its ester, alkanolamine, amine (trimethylamine, triethylamine, etc.), paraffin wax, silane coupling agent, silicone, polysiloxane, etc. Specific examples of the silane coupling agent include the silane coupling agents described above.

[0031] The average particle size of the inorganic filler is preferably 25 μm or less, more preferably 15 μm or less, and is preferably 0.1 μm or more. The shape of the inorganic filler may be any of granular, needle-like (fibrous), and plate-like.Specific shapes of the inorganic filler include spherical, scale-like, layered, leaf-like, apricot kernel-like, columnar, cockscomb-like, equiaxial, leaf-like, mica-like, block-like, flat, wedge-like, rosette-like, mesh-like, and prismatic.The inorganic filler may be hollow, and may include hollow fillers and non-hollow fillers.

[0032] Specific examples of inorganic fillers include silica fillers (Admatechs' "Admafine", Taiheiyo Cement's "E-SPHERES" series, Nittetsu Mining's "Silinax" series, Emerson & Cumming's "Ecocosfyer" series, Denka's "SFP" series, etc.), zinc oxide surface-treated with esters such as propylene glycol dicaprate (Sakai Chemical Industry Co., Ltd.'s "FINEX" series, etc.), titanium oxide fillers coated with polyhydric alcohols and inorganic substances (Ishihara Sangyo Kaisha's "Tipaque" series, etc.), rutile-type titanium oxide surface-treated with alkylsilanes (Teika's "JMT" series, etc.), talc fillers (Nippon Talc's "SG" series, etc.), steatite fillers (Nippon Talc's "BST" series, etc.), and magnesium oxide fillers (Ube Material Industries, Ltd.'s "Magnesia" series, etc.).

[0033] When the curable compound is an epoxy compound, the composition preferably further contains a crosslinking agent. The crosslinking agent is an agent that reacts with the F polymer or the epoxy compound to form a crosslinked structure, and is a compound having two or more groups that can react with a hydroxyl group-containing group, a carbonyl group-containing group, or an epoxy group. The crosslinking agent is a compound different from any of the F polymer, the curable compound, the curing agent, and the inorganic filler. Since the present composition has excellent liquid physical properties, if a crosslinking agent is added, when a molded article is formed from the composition, the crosslinking density of the polymer matrix can be adjusted, and the flexibility and adhesiveness of the molded article can be easily adjusted to a high degree.

[0034] Examples of the crosslinking agent include a compound having two or more acid anhydride residues (acid anhydride type crosslinking agent), a compound having two or more ester groups (ester type crosslinking agent), a compound having two or more carbonate groups (carbonate type crosslinking agent), a compound having two or more cyanate groups (cyanate type crosslinking agent), and a compound having two or more isocyanate groups (isocyanate type crosslinking agent). The crosslinking agent is preferably an ester type crosslinking agent or an isocyanate type crosslinking agent. The isocyanate type crosslinking agent is preferably a compound having two or more isocyanate groups or a compound having two or more blocked isocyanate groups. Specific examples of isocyanate-type crosslinking agents include the "Sumidur BL" series and the "Desmodur TPL" series (both manufactured by Sumika Covestro Urethane Co., Ltd.), the "Coronate 2500 series" series (manufactured by Tosoh Corporation), the "NATE" series (manufactured by Asahi Kasei Corporation), and Karenz MOI-BM (manufactured by Showa Denko K.K.).

[0035] From the viewpoint of imparting developability to a molded article formed from the composition and using it as a resist material for forming a pattern layer on a substrate, it is preferable that the composition further contains an alkali-soluble polymer. The alkali-soluble polymer is preferably a polymer having an acidic group, more preferably a polymer having a carboxyl group or a phenolic hydroxyl group. The alkali-soluble polymer also includes a polymer that exhibits alkali solubility by exposure to light or heat. The alkali-soluble polymer is a compound different from any of F polymer, curable compound, curing agent, inorganic filler, and crosslinking agent. Examples of the alkali-soluble polymer include (meth)acrylate polymers having a phenolic hydroxyl group or a carboxyl group, polycarbonates having a phenolic hydroxyl group or a carboxyl group, polyurethanes having a phenolic hydroxyl group or a carboxyl group, and oxacene polymers having a carboxyl group. The phenolic hydroxyl group or the carboxyl group of these polymers may be protected by a protecting group that is eliminated by exposure to light or heat.

[0036] The present composition may further contain a surfactant from the viewpoint of improving dispersibility and handling properties. The surfactant is preferably nonionic. The hydrophilic site of the surfactant preferably has an oxyalkylene group or an alcoholic hydroxyl group. The oxyalkylene group may be composed of one type or two or more types. In the latter case, the different types of oxyalkylene groups may be arranged randomly or in a block form. The oxyalkylene group is preferably an oxyethylene group.

[0037] The hydrophobic portion of the surfactant preferably has an acetylene group, a polysiloxane group, a perfluoroalkyl group, or a perfluoroalkenyl group, i.e., the surfactant is preferably an acetylene-based surfactant, a silicone-based surfactant, or a fluorine-based surfactant. Among these, the surfactant is more preferably a fluorosurfactant, and even more preferably a fluorosurfactant having a hydroxyl group (particularly an alcoholic hydroxyl group) or an oxyalkylene group and a perfluoroalkyl group or a perfluoroalkenyl group. Specific examples of such surfactants include the "Ftergent" series (manufactured by Neos), the "Surflon" series (manufactured by AGC Seimi Chemical), the "Megafac" series (manufactured by DIC), and the "Unidyne" series (manufactured by Daikin Industries, Ltd.).

[0038] The composition may further include another resin. The other resin may be a thermosetting resin or a thermoplastic resin. The other resin is preferably an aromatic polymer, in which case the molded product tends to have excellent UV absorption properties and UV processability. Examples of other resins include maleimide resins, urethane resins, polyimides, polyamic acids, polyamideimides, polyphenylene ethers, polyphenylene oxides, liquid crystal polyesters, and fluoropolymers other than F polymers.

[0039] As the other resin, maleimide resin, polyimide and polyamic acid are preferable. In this case, a molded product formed from the present composition is likely to have excellent flexibility and adhesiveness. As the other resin, maleimide resin, thermoplastic polyimide and polyamic acid, all of which are aromatic, are more preferable. In addition to these components, the present composition may contain additives such as a silane coupling agent, a dehydrating agent, an antifoaming agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a brightening agent, a colorant, a conductive agent, a release agent, a surface treatment agent, and a flame retardant.

[0040] The total content of the F polymer, the curable compound, the curing agent and the inorganic filler in the composition is 60% by mass or more, preferably 75% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. The sum of the above contents is preferably 100% by mass or less. In addition, when the present composition contains components for forming a molded product other than the F polymer, the curable compound, the curing agent, and the inorganic filler (for example, when the composition contains the above-mentioned crosslinking agent or the alkali-soluble polymer), the total content thereof is more than 60 mass%, preferably more than 75 mass%, more preferably 90 mass% or more, and even more preferably more than 95 mass%. The total content is preferably 100 mass% or less.

[0041] The composition does not contain a solvent, or contains a solvent and the content of the solvent is preferably 40% by mass or less. The content of the solvent in the composition is preferably 25% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. The lower limit of the content of the solvent in the composition is 0%. The solvent is an inactive compound that is liquid at 25°C, does not react with any of the components forming the above-mentioned molded product, and has the ability to dissolve or disperse the components forming the above-mentioned molded product. Specific examples of the solvent include water, cellosolve-based solvents, ester-based solvents, propylene glycol-based solvents, ketone-based solvents, alcohol-based solvents, amide-based solvents, and aromatic hydrocarbon-based solvents.

[0042] The content of F powder in the present composition is preferably 30% by mass or less, more preferably 20% by mass or less, and preferably 1% by mass or more, more preferably 5% by mass or more. The content of the curable compound in the present composition is preferably 30% by mass or less, more preferably 20% by mass or less, and is preferably 5% by mass or more, more preferably 10% by mass or more. The content of the curing agent in the present composition is preferably 15% by mass or less, more preferably 10% by mass or less, and is preferably 1% by mass or more, more preferably 5% by mass or more. The content of the inorganic filler in the composition is preferably more than 30% by mass, more preferably 40% by mass or more, and is preferably 75% by mass or less, more preferably 60% by mass or less. In this composition, it is preferable that the ratio of the content of the curable compound to the content of the F powder is 1 to 5, the ratio of the content of the curing agent to the content of the curable compound is 0.1 to 0.3, and the ratio of the content of the inorganic filler to the content of the F powder is more than 1 and not more than 5.

[0043] The composition can be suitably used as a filling material for filling through holes or recesses in multilayer printed wiring boards. The multilayer printed wiring board has a plurality of circuit patterns laminated with insulating layers interposed therebetween. The insulating layer is composed of polyphenylene ether, polyphenylene oxide, cyanate ester, polyimide, fluoropolymer, etc. The circuit pattern is composed of a metal film formed by plating or the like. The multilayer printed wiring board also has a through hole penetrating in the thickness direction or a recessed portion recessed therein. The through hole or recess is formed by drilling or laser processing. A conductive film is formed on the inner surface of the through hole or recess, and the predetermined circuit patterns are electrically connected to each other. When the present composition is filled into the through hole or recess and cured by heating, the through hole or recess can be filled.

[0044] The composition can be filled into the through-holes or recesses by screen printing, roll coating, die coating, or vacuum printing. In this case, it is preferable to fill the composition to such an extent that it overflows from the through-holes or recesses. The heating conditions of the present composition are preferably 80 to 160° C. for 30 to 180 minutes. From the viewpoint of suppressing outgassing during curing of the present composition, it is preferable to cure the present composition in two stages, a provisional curing stage and a main curing stage. Pre-curing conditions are preferably 80 to 110° C. for 30 to 90 minutes. In this case, the hardness of the pre-cured cured product is relatively low, so that unnecessary parts protruding from the through-holes or recesses can be easily removed by polishing, etching, etc. The hardness of the cured product can be adjusted by changing the heating time and heating temperature during pre-curing.

[0045] The conditions for the main curing are preferably 130 to 160°C and 30 to 180 minutes. This main curing produces a molded product (filler) that has high adhesion to the insulating layer of the multilayer printed wiring board. In addition, since the volume change rate of this composition during curing is small, it is possible to prevent a decrease in the shape stability of the multilayer printed wiring board. The cross-sectional void ratio of the molded product obtained from the composition is preferably 5% or less, more preferably 3% or less. The lower limit of the cross-sectional void ratio is 0%. Since the composition has a low content of volatile components, voids are unlikely to occur when the molded product is molded. At this stage, unnecessary parts protruding from the through holes or recesses of the molded product may be removed to make the surface flat. After that, a metal film may be formed on the surface of the multilayer printed wiring board by plating or the like, and the surface may be patterned into a predetermined pattern to form a circuit pattern. Prior to the formation of the metal film, the surface of the multilayer printed wiring board may be subjected to a roughening treatment using an aqueous potassium permanganate solution or the like, if necessary.

[0046] The composition can also be suitably used to prepare a dry film. Such a dry film can be produced by applying the composition to a carrier film and drying it to form a resin film as a dry coating. If necessary, a protective film may be laminated on the dry film. The carrier film is a film that has a function of supporting the dry film. Examples of such a carrier film include polyolefin film, polyester film, polyimide film, polyamideimide film, polytetrafluoroethylene film, polystyrene film, and surface-treated paper substrate. Among them, polyester film is preferred from the viewpoints of heat resistance, mechanical strength, handling, etc. The thickness of the carrier film is preferably 10 to 150 μm. The surface of the carrier film may be subjected to a release treatment.

[0047] The protective film is a film that is attached to the surface of the dry film opposite the carrier film for the purposes of preventing dust and the like from adhering to the surface of the dry film and improving its ease of handling. The protective film may be, for example, the same film or paper substrate as those exemplified for the carrier film, with polyolefin films or polyester films being preferred. The thickness of the protective film is also preferably 10 to 150 μm. The surface of the protective film may be subjected to a release treatment.

[0048] Such a three-layer laminate film (the sheet of the present invention) can be used to manufacture a printed wiring board. First, either the carrier film or the protective film is peeled off from the dry film, and the film is pressed onto a circuit board on which a circuit pattern is formed, and then thermally cured. An oven, a heat press, or the like can be used for thermal curing. After that, through holes (via holes) are formed by laser processing or drilling at predetermined locations on the circuit board to expose the circuit pattern. This results in a printed wiring board. Note that if unnecessary components (smears) remain on the circuit pattern because they cannot be completely removed, it is preferable to perform a desmear process. The other of the carrier film and the protective film is peeled off from the dry film at a predetermined stage. For electrical connection between the circuit patterns, a conductive film formed on the inner surface of the through hole, or a pillar or post housed in the through hole can be used.

[0049] The composition can also be suitably used as a solder resist. The solder resist can be applied onto the circuit board by a coating method such as screen printing, bar coating, or blade coating. After coating, the coating is preferably dried to obtain touch-dry properties, preferably at 75 to 95° C. for 40 to 70 minutes. For drying, a hot air circulation drying oven or a far infrared drying oven can be used. The thickness of the coating film after drying (dried film) is preferably from 10 to 150 μm, and more preferably from 20 to 60 μm, from the viewpoint of improving the developability and printability of the dried film.

[0050] Next, the dried film is irradiated with exposure light using an exposure mask having a predetermined exposure pattern (openings). The exposure light source may be a halogen lamp, a high-pressure mercury lamp, a laser light, a metal halide lamp, a black lamp, an electrodeless lamp, etc. The exposure dose is an integrated light dose of 200 mJ / cm2. 2 It is preferable that: Alternatively, a pattern may be formed in the dried film by a laser direct imaging device without using an exposure mask.

[0051] Next, the dried film is developed with a developer, whereby unnecessary portions of the dried film are removed to obtain a dried film having a predetermined pattern. The developer can be applied to the dried exposed coating by spraying, immersion, or the like. The developer is preferably an aqueous alkali solution containing an alkali such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, or sodium silicate, and more preferably a dilute aqueous alkali solution containing an alkali at a concentration of 1.5% by mass or less. According to the present composition, a dilute alkaline aqueous solution can be used as a developer, so that a dried film with excellent resolution can be obtained with little damage.

[0052] A specific embodiment of the developer is preferably a dilute alkaline aqueous solution containing sodium carbonate at a concentration of 0.2 to 2.0% by mass. After development, the dried film is preferably washed with water or neutralized with an acid in order to remove unnecessary developer. The resulting dry coating after development is then cured by heating or exposure to ultraviolet light, resulting in a cured coating (molded product) with excellent printability, adhesion, and crack resistance. In the case of curing by heating, the heating temperature is preferably 180° C. or less, more preferably 150° C. or less. On the other hand, in the case of curing by irradiation with ultraviolet rays, the irradiation intensity of the ultraviolet rays is 500 to 3000 mJ / cm. 2 is preferable, and 500 to 2000 mJ / cm 2 is more preferred. EXAMPLES

[0053] 1. Preparation of each ingredient [F Polymer] F Polymer 1: PFA-based polymer containing 98.0 mol%, 0.1 mol%, and 1.9 mol% of TFE units, NAH units, and PPVE units, in that order, and having an oxygen-containing polar group (melting temperature: 300°C) Non-F polymer 1: PFA-based polymer containing 98.7 mol% TFE units and 1.3 mol% PPVE units, in that order, and having no oxygen-containing polar group (melting temperature: 305°C) [powder] Powder 1: Powder made of F polymer 1, D50 2.1μm Powder 2: Powder made of non-F polymer 1, with a D50 of 1.8 μm

[0054] [Curable liquid compound] Curable compound 1: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, "jER828") Curable compound 2: diglycidylaniline (manufactured by Nippon Kayaku Co., Ltd., "GAN") [Hardening agent] Hardener 1: Imidazole hydroxymethyl (Shikoku Chemical Industry Co., Ltd., "2PHZ") Hardener 2: Modified aliphatic polyamine (manufactured by Fuji Chemical Industry Co., Ltd., "Fujicure FXR-1030")

[0055] [Inorganic filler] Filler 1: Silica filler with D50 of 0.4 μm [Antifoaming agent] Antifoaming agent 1: Silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., "KS-66")

[0056] 2. Example of Production of Liquid Composition As shown in Table 1 below, various components were blended in the prescribed ratios (parts by mass), premixed with a stirrer, and then dispersed with a three-roll mill to prepare Liquid Compositions 1 and 2. [Table 1]

[0057] 3. Evaluation of viscosity of liquid composition The viscosities of Liquid Compositions 1 and 2 were measured using the method described above. As a result, the viscosity of Liquid Composition 1 was 8000 mPa·s, and the viscosity of Liquid Composition 2 was more than 100000 mPa·s.

[0058] 4. Manufacturing of hole-filled multilayer printed wiring boards First, a through hole with an inner diameter of 0.3 mm and a depth of 3.2 mm was formed in a multilayer printed wiring board by drilling. Next, a conductive film (thickness: 25 μm) was formed on the entire inner surface of the through hole by copper plating. Next, each liquid composition was filled into the through hole by screen printing, and cured by heating at 150° C. for 30 minutes in a hot air circulation drying oven (manufactured by Yamato Scientific Co., Ltd., "DF610"). After cutting the multilayer printed wiring board in the direction perpendicular to the thickness direction, the cut surfaces were polished using SiC abrasive paper (Marumoto Struers K.K., "500" and "2000") and a polishing machine (Harzok Japan K.K., "FORCIPOL-2V"). When the cross-sections of the through holes filled with the cured liquid composition were observed using an optical microscope and an electron microscope, the proportion of voids in the cross-sectional area of ​​the through holes (cross-sectional void ratio) was 5% or less when Liquid Composition 1 was used, and was greater than 5% when Liquid Composition 2 was used. [Industrial Applicability]

[0059] The liquid composition of the present invention has excellent dispersion stability and handling properties, and can be used to produce molded products (films, impregnated products such as prepregs, laminates, etc.) having properties based on the physical properties of the F polymer. The molded product of the present invention is useful as antenna parts, printed circuit boards, aircraft parts, automobile parts, sports equipment, food industry products, paints, cosmetics, etc., and specifically, it is useful as electric wire covering materials (aircraft electric wires, etc.), electrical insulating tapes, insulating tapes for oil drilling, materials for printed circuit boards (particularly, materials for filling holes in printed circuit boards), separation membranes (microfiltration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes, gas separation membranes, etc.), electrode binders (for lithium secondary batteries, for fuel cells, etc.), copy rolls, furniture, automobile dashboards, covers for home appliances, etc., sliding members (load bearings, sliding shafts, valves, bearings, gears, cams, belt conveyors, food transport belts, etc.), tools (shovels, files, saws, saws, etc.), boilers, hoppers, pipes, ovens, baking molds, chutes, dies, toilets, and container covering materials.

Claims

1. The composition comprises a powder of a tetrafluoroethylene polymer having a hydroxyl group-containing group or a carbonyl group-containing group and a melting temperature of 200 to 320°C, a compound having two or more epoxy groups or (meth)acryloyloxy groups, a curing agent, and an inorganic filler; the content of the tetrafluoroethylene-based polymer is 30% by mass or less, the content of the compound is 30% by mass or less, the content of the curing agent is 15% by mass or less, and the content of the inorganic filler is more than 30% by mass, the total content of the tetrafluoroethylene-based polymer, the compound, the curing agent, and the inorganic filler is 60% by mass or more, and the composition does not contain a solvent, or contains a solvent and the content of the solvent is 40% by mass or less; A liquid composition having a viscosity of 1,000 mPa·s or more and 100,000 mPa·s or less, as measured at 25° C. and a rotation speed of 30 rpm using a Brookfield viscometer.

2. The liquid composition according to claim 1, further comprising an alkali-soluble polymer, and the total content of the tetrafluoroethylene-based polymer, the compound, the curing agent, the inorganic filler and the alkali-soluble polymer is more than 60 mass%.

3. The liquid composition according to claim 1 or 2, wherein the tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer that contains units based on perfluoro(alkyl vinyl ether) and has a carbonyl group-containing group.

4. The liquid composition according to any one of claims 1 to 3, wherein the powder has an average particle size of 0.1 to 6 µm.

5. The liquid composition according to any one of claims 1 to 4, wherein the inorganic filler is a filler containing silicon oxide.

6. The liquid composition according to any one of claims 1 to 5, wherein the inorganic filler has an average particle size of 0.1 to 25 µm.

7. The liquid composition according to any one of claims 1 to 6, wherein the compound is a liquid compound having two or more epoxy groups.

8. The liquid composition according to any one of claims 1 to 7, wherein the compound is a liquid compound having two or more epoxy groups and a tertiary amine structure.

9. The liquid composition according to any one of claims 1 to 8, wherein the curing agent is an amine, an imidazole, a phenol or an acid anhydride.

10. The liquid composition according to any one of claims 1 to 9, which is a filling material used for filling through holes or recesses in a multilayer printed wiring board.

11. A sheet having a layer formed from the liquid composition according to any one of claims 1 to 10.

Images