Liquid polyolefin composition

Abstract

To provide a liquid polyolefin composition which gives a cured product excellent in low dielectric characteristics and heat resistance, a cured product of the liquid polyolefin composition, and a film comprising the cured product.SOLUTION: The liquid polyolefin composition contains a modified polyolefin (A), a curing agent (B), an initiator (C), and an organic solvent (S). A chain polyolefin modified with a monomer having a polar group is used as the modified polyolefin (A). The content of the curing agent (B) is 2.5-30 pts.mass based on 100 pts.mass of the modified polyolefin (A). The content of the initiator (C) is 0.5-2.7 pts.mass based on 100 pts.mass of the modified polyolefin (A).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a liquid polyolefin composition, a cured product of the liquid polyolefin composition, a film made of the cured product, and a method for producing the film.

Background Art

[0002] In recent years, in communication devices such as smartphones and electronic devices such as next-generation TVs, it has been required to transmit and receive large amounts of data at high speed. Along with this, the frequency of electrical signals has been increasing. Specifically, in the field of wireless communication, around 2020, the introduction of the fifth-generation mobile communication system (5G) is expected. When introducing the fifth-generation mobile communication system, the use of a high-frequency band of 10 GHz or higher is being considered.

[0003] However, as the frequency of the signal used increases, the quality of the output signal that may cause misrecognition of information deteriorates, that is, the transmission loss increases. This transmission loss consists of conductor loss due to the conductor and dielectric loss due to the resin for insulation that constitutes electrical and electronic components such as substrates in electronic devices and communication devices. Since the conductor loss is proportional to the 0.5th power of the frequency used and the dielectric loss is proportional to the first power of the frequency, in the high-frequency band, especially in the GHz band, the influence of this dielectric loss becomes very large.

[0004] Therefore, in order to reduce the transmission loss, a low-dielectric material with a low relative permittivity and a low dielectric tangent, which are factors related to the dielectric loss, is required. Under such circumstances, as a low-dielectric material that can be used in a high-frequency band, for example, the use of a composition containing polyolefin having excellent electrical properties such as low dielectric loss and low dielectric tangent has been studied (see Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] A preferred application for materials with excellent low dielectric properties is flexible printed circuit boards. In flexible printed circuit boards, materials with low dielectric properties are typically used as films.

[0007] Flexible printed circuit boards (PCBs) are often exposed to high temperatures in reflow ovens for surface mounting applications. Therefore, flexible printed circuit boards require high heat resistance to withstand the heating in reflow ovens.

[0008] The present invention has been made in view of the above problems, and aims to provide a liquid polyolefin composition that gives a cured product with excellent low dielectric properties and heat resistance, a cured product of the liquid polyolefin composition, and a film made from the cured product. [Means for solving the problem]

[0009] The inventors of this invention have diligently studied and investigated the above problems, and as a result have completed this invention.

[0010] In other words, the present invention provides the following (1) to (14). (1) comprising a modified polyolefin (A), a curing agent (B), an initiator (C), and an organic solvent (S), Modified polyolefin (A) is a chain-like polyolefin modified with monomers having polar groups. The content of the curing agent (B) is 2.5 to 30 parts by mass per 100 parts by mass of modified polyolefin (A). A liquid polyolefin composition in which the initiator (C) content is 0.5 to 2.7 parts by mass per 100 parts by mass of modified polyolefin (A). (2) The liquid polyolefin composition according to (1), wherein the mass of the curing agent (B) is 5 to 30 times the mass of the initiator (C). (3) The liquid polyolefin composition according to (1) or (2), wherein the organic solvent (S) comprises a hydrocarbon solvent and / or an ether solvent. (4) The liquid polyolefin composition according to any one of (1) to (3), wherein the ratio of the mass of components other than the organic solvent (S) contained in the liquid polyolefin composition to the mass of the liquid polyolefin composition is 3 to 40% by mass. (5) A liquid polyolefin composition according to any one of (1) to (4), wherein the curing agent (B) has two or more groups selected from the group consisting of vinyl groups, allyl groups, and (meth)acryloyl groups. (6) A liquid polyolefin composition according to any one of (1) to (5), wherein the 10-hour half-life temperature of the initiator (C) is 100°C or higher. (7) A liquid polyolefin composition according to any one of (1) to (6), wherein the 10-hour half-life temperature of the initiator (C) is higher than the boiling point of the organic solvent (S) at atmospheric pressure. (8) A liquid polyolefin composition according to any one of (1) to (7), wherein the amount of modification of the modified polyolefin (A) by a monomer having a polar group is 0.05 to 1.50% by mass. (9) A liquid polyolefin composition according to any one of (1) to (8), wherein the modified polyolefin (A) comprises polymethylpentene modified with a monomer having a polar group. (10) The liquid polyolefin composition according to any one of (1) to (9), wherein the ratio of the mass of modified polyolefin (A) to the total mass of resin components contained in the liquid polyolefin composition is 50% by mass or more. (11) A liquid polyolefin composition according to any one of (1) to (10) that gives a cured film exhibiting a peel strength of 3.0 N / cm or more as measured by the method consisting of steps 1) to 5) below. 1) A step of casting a liquid polyolefin composition onto a glass substrate. 2) A step of drying the cast liquid polyolefin composition by heating it at 50°C for 10 minutes, followed by heating it at 80°C for 30 minutes. 3) The step of peeling the film formed after drying from the glass substrate to obtain an uncured film. 4) The step of sandwiching the uncured film between two electrolytic copper foils and performing pressing at a pressing temperature of 180 °C, a pressing pressure of 2.0 MPa, and a pressing time of 10 minutes to obtain a laminated film. 5) The step of measuring the peel strength in accordance with "6.5 Peel Strength" of JIS C6471 using the obtained laminated film. (12) A cured product of the liquid polyolefin composition according to (1) to (11). (13) The cured product according to (12), having a relative dielectric constant Dk at 10 GHz of 2.30 or less and a dielectric loss tangent Df at 10 GHz of 0.0020 or less. (14) A film made of the cured product according to (12) or (13). (15) Coating the liquid polyolefin composition according to any one of (1) to (11) on a substrate to form a coating film, removing the organic solvent (S) from the coating film to obtain an uncured film, and curing the uncured film, which is a method for producing the film according to (13). [Effect of the Invention]

[0011] According to the present invention, it is possible to provide a liquid polyolefin composition that gives a cured product excellent in low dielectric characteristics and heat resistance, a cured product of the liquid polyolefin composition, and a film made of the cured product. [Embodiments for Carrying out the Invention]

[0012] ≪Liquid Polyolefin Composition≫ The liquid polyolefin composition is a liquid composition containing a modified polyolefin (A), a curing agent (B), an initiator (C), and an organic solvent (S). The modified polyolefin (A) is a chain polyolefin modified with a monomer having a polar group. The chain polyolefin is a polyolefin having no cyclic structure in the main chain. The curing agent (B) crosslinks with other curing agents (B) or between the curing agent (B) and the modified polyolefin (A) to crosslink the liquid polyolefin composition. The initiator (C) is a component that cures the curing agent (B). The content of the curing agent in the liquid polyolefin composition is 2.5 to 30 parts by mass with respect to 100 parts by mass of the modified polyolefin (A). The content in the liquid polyolefin composition is 0.5 to 2.7 parts by mass with respect to 100 parts by mass of the modified polyolefin (A).

[0013] Hereinafter, the essential or optional components included in the liquid polyolefin composition will be described.

[0014] <Modified polyolefin (A)> The modified polyolefin (A) is a chain polyolefin modified with a monomer having a polar group.

[0015] Here, a polar group refers to a group of atoms that have polarity, and when this group is present in an organic compound, the compound becomes polar. Specific examples of polar groups that can be introduced into linear polyolefins by modification with monomers containing polar groups include: carboxyl groups derived from unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, and isocrotonic acid; acid anhydride groups, halocarbonyl groups, carboxylic acid amide groups, imide groups, and carboxylic acid ester groups derived from derivatives of the aforementioned unsaturated carboxylic acids such as acid anhydrides, acid halides, amides, imides, and esters; and glycidyl methacrylate and glycidyl acrylate. Examples of epoxy groups include zyl, monoglycidyl maleate, diglycidyl maleate, monoglycidyl itaconicate, diglycidyl itaconicate, monoglycidyl allylsuccinate, diglycidyl allylsuccinate, p-styrenecarboxylic acid glycidyl, allylglycidyl ether, methacrylate glycidyl ether, styrene-p-glycidyl ether, p-glycidylstyrene, 3,4-epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene, and epoxy groups derived from epoxy group-containing vinyl monomers such as vinylcyclohexene monooxide. Among these polar groups, epoxy groups are preferred because they facilitate the formation of cured products with good adhesion to polyimide resins and copper foils using a liquid polyolefin composition with a graft-modified polyolefin composition or its crosslinked product, and because of the good crosslinking reactivity between the modified polyolefin (A) and the curing agent (B).

[0016] Typically, modified polyolefins (A) are resins in which a chain-like polyolefin is graft-modified with a vinyl monomer having polar groups in the presence of a radical polymerization initiator, or copolymer-modified resins obtained by copolymerizing a monomer that gives a chain-like polyolefin with a vinyl monomer having polar groups in the presence of a radical polymerization initiator. In terms of facilitating modification with monomers having polar groups, it is preferable that the modified polyolefin (A) is a resin in which a chain-like polyolefin has been graft-modified with vinyl monomers having polar groups in the presence of a radical polymerization initiator.

[0017] The modified polyolefin (A), which is a graft-modified polyolefin, is preferably a linear polyolefin graft-modified with a vinyl monomer having a polar group and an aromatic vinyl monomer, and more preferably a linear polyolefin graft-modified with glycidyl (meth)acrylate and styrene.

[0018] Examples of chain-like polyolefins include polyethylene, polypropylene, poly-1-butene, polyisobutylene, polymethylpentene, propylene-ethylene copolymer, ethylene-propylene-diene copolymer, ethylene / butene-1 copolymer, and ethylene / octene copolymer.

[0019] Among these linear polyolefins, polymethylpentene, polyethylene, polypropylene, and propylene-ethylene copolymers are preferred because they undergo modification reactions easily, and polymethylpentene is more preferred in terms of heat resistance and low dielectric properties.

[0020] Radical polymerization initiators that can be used in the production of modified polyolefins (A) include, for example, ketone peroxides such as methyl ethyl ketone peroxide and methyl acetacetate peroxide; peroxyketals such as 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, and 2,2-bis(tert-butylperoxy)butane; hydroperoxides such as permethane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, diisopropylbenzene hydroperoxide, and cumene hydroperoxide; dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, α,α'-bis(tert-butylperoxy-m-isopropyl)benzene, t Examples include dialkyl peroxides such as ert-butylcumyl peroxide, di-tert-butyl peroxide, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexine-3; diacyl peroxides such as benzoyl peroxide; peroxy dicarbonates such as di(3-methyl-3-methoxybutyl)peroxydicarbonate and di-2-methoxybutyl peroxydicarbonate; tert-butyl peroxyoctate, tert-butyl peroxyisobutyrate, tert-butyl peroxylaurate, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxyisopropyl carbonate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butyl peroxyacetate, tert-butyl peroxybenzoate, and peroxyesters such as di-tert-butyl peroxyisophthalate. The above-mentioned radical polymerization initiators can be used individually or in combination of two or more.

[0021] The amount of radical polymerization initiator used is not particularly limited as long as the modification reaction proceeds smoothly. When performing copolymerization modification, the amount of radical polymerization initiator used is preferably 0.01 parts by mass or more and 10 parts by mass or less, and more preferably 0.2 parts by mass or more and 5 parts by mass or less, per 100 parts by mass of monomer that yields modified polyolefin (A). When performing graft modification, the amount of radical polymerization initiator used is preferably 0.01 parts by mass or more and 10 parts by mass or less, and more preferably 0.2 parts by mass or more and 5 parts by mass or less, per 100 parts by mass of the linear polyolefin.

[0022] Examples of vinyl monomers having polar groups that can be used for modification include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, and isocrotonic acid; derivatives of these unsaturated carboxylic acids such as acid anhydrides, acid halides, amides, imides, and esters; and epoxy group-containing vinyl monomers such as glycidyl methacrylate, glycidyl acrylate, monoglycidyl maleic acid, diglycidyl maleic acid, monoglycidyl itaconic acid, diglycidyl itaconic acid, monoglycidyl allylsuccinate, diglycidyl allylsuccinate, glycidyl p-styrenecarboxylic acid, allylglycidyl ether, methacrylic glycidyl ether, styrene-p-glycidyl ether, p-glycidylstyrene, 3,4-epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene, and vinylcyclohexene monooxide.

[0023] Among these, epoxy group-containing vinyl monomers are preferred, glycidyl methacrylate and glycidyl acrylate are more preferred, and glycidyl methacrylate is particularly preferred.

[0024] The vinyl monomers having the polar groups described above can be used individually or in combination of two or more types.

[0025] When copolymerization modification is performed, the amount of polar group-containing vinyl monomer used for modification is preferably 0.1 parts by mass to 12 parts by mass, more preferably 0.5 parts by mass to 10 parts by mass, and particularly preferably 1 part by mass to 8 parts by mass, per 100 parts by mass of monomers other than the polar group-containing vinyl monomer. When graft modification is performed, the amount of vinyl monomer having polar groups used for modification is preferably 0.1 parts by mass or more and 12 parts by mass or less, more preferably 0.5 parts by mass or more and 10 parts by mass or less, and particularly preferably 1 part by mass or more and 8 parts by mass or less, per 100 parts by mass of the linear polyolefin.

[0026] By using a modified polyolefin (A) modified with a vinyl monomer having an amount of polar groups within this range, a cured product with excellent low dielectric properties and heat resistance can be obtained, making it easy to obtain a liquid polyolefin composition with excellent curability.

[0027] As mentioned above, the modified polyolefin (A) is preferably a polyolefin graft-modified with a vinyl monomer having a polar group and an aromatic vinyl monomer.

[0028] By using a vinyl monomer with polar groups and an aromatic vinyl monomer in combination, the modification reaction, particularly the grafting reaction, is stabilized, making it easier to introduce the vinyl monomer with polar groups into the desired amount of modified polyolefin (A).

[0029] Specific examples of aromatic vinyl monomers include styrene; alkylstyrenes such as o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, β-methylstyrene, dimethylstyrene, and trimethylstyrene; chlorostyrenes such as o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, α-chlorostyrene, β-chlorostyrene, dichlorostyrene, and trichlorostyrene; bromostyrenes such as o-bromostyrene, m-bromostyrene, p-bromostyrene, dibromostyrene, and tribromostyrene; o-fluorostyrene, m-fluorostyrene, p-fluoro Examples include fluorostyrenes such as rostylen, difluorostyrene, and trifluorostyrene; nitrostyrenes such as o-nitrostyrene, m-nitrostyrene, p-nitrostyrene, dinitrostyrene, and trinitrostyrene; hydroxystyrenes such as o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, dihydroxystyrene, and trihydroxystyrene; and dialkenylbenzenes such as o-divinylbenzene, m-divinylbenzene, p-divinylbenzene, o-diisopropenylbenzene, m-diisopropenylbenzene, and p-diisopropenylbenzene.

[0030] Among these aromatic vinyl monomers, styrene, α-methylstyrene, p-methylstyrene, o-divinylbenzene, m-divinylbenzene, p-divinylbenzene, or a mixture of divinylbenzene isomers are preferred in terms of low cost, with styrene being particularly preferred.

[0031] Aromatic vinyl monomers can be used individually or in combination of two or more types.

[0032] When copolymerization modification is performed, the amount of aromatic vinyl monomer used for modification is preferably 0.1 parts by mass or more and 12 parts by mass or less, more preferably 0.5 parts by mass or more and 10 parts by mass or less, and particularly preferably 1 part by mass or more and 8 parts by mass or less, per 100 parts by mass of the monomer of the aromatic vinyl monomer. When graft modification is performed, the amount of aromatic vinyl monomer used for modification is preferably 0.1 parts by mass or more and 12 parts by mass or less, more preferably 0.5 parts by mass or more and 10 parts by mass or less, and particularly preferably 1 part by mass or more and 8 parts by mass or less, per 100 parts by mass of the linear polyolefin.

[0033] The amount of modification by monomers having polar groups in the modified polyolefin (A) described above is preferably 0.05 to 1.50% by mass, more preferably 0.10 to 1.00% by mass, and particularly preferably 0.15 to 0.50% by mass. As long as the amount of modification by monomers containing polar groups is within the above range, it is easy to form a cured product with excellent low dielectric properties. The amount of modification by monomers containing polar groups can be measured by known methods, depending on the type of polar group. For example, if the polar group is an epoxy group, the amount of modification by monomers containing polar groups can be measured by a titration method in accordance with JIS K7236, as described later in the examples.

[0034] The melting point of the modified polyolefin (A) is not particularly limited. The melting point of the modified polyolefin (A) is preferably 80°C or higher, more preferably 100°C or higher, and even more preferably 120°C to 240°C. From the viewpoint of heat resistance of the molded product, it is preferable that the melting point of the modified polyolefin (A) is 200°C or higher. The melting point of the modified polyolefin (A) is at the above temperature, which allows for good heat resistance to be imparted to the crosslinked polyolefin layer formed using the graft-modified polyolefin composition. Furthermore, if the melting point of the modified polyolefin (A) is 240°C or lower, it is easier to suppress the decomposition and sublimation of the curing agent (B) when preparing or using the liquid polyolefin composition.

[0035] As will be described later, the liquid polyolefin composition may contain other resins besides the modified polyolefin (A). In terms of easily obtaining the desired effects by using the liquid polyolefin composition, the ratio of the mass of modified polyolefin (A) to the total mass of the resin components contained in the liquid polyolefin composition is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass.

[0036] <Hardening agent (B)> The liquid polyolefin composition contains a curing agent (B). The curing agent (B) cures the liquid polyolefin composition by crosslinking curing agents (B) with each other, or with the modified polyolefin (A).

[0037] The liquid polyolefin composition is cured by crosslinking treatments such as heating or electron beam irradiation, which are selected according to the type of reactive functional group present in the curing agent (B) and the type of initiator (C) described later. The curing agent (B) may be used alone or in combination of two or more types.

[0038] The curing agent (B) is a compound having two or more reactive functional groups within the same molecule. Examples of reactive functional groups in curing agent (B) include carbon-carbon double bond-containing groups, halogen atoms, dicarboxylic acid anhydride groups, carboxyl groups, amino groups, cyano groups, and hydroxyl groups. The multiple reactive functional groups in curing agent (B) within the same molecule may be the same or different. Among the reactive functional groups mentioned above, carbon-carbon double bond-containing groups are preferred because they exhibit superior crosslinking reactivity and stability of the crosslinked structure after crosslinking. Examples of carbon-carbon double bond-containing groups include alkenyl groups such as vinyl groups, allyl groups, and methallyl groups, unsaturated acyl groups such as (meth)acryloyl groups, and maleimide groups. Preferred carbon-carbon double bond-containing groups are alkenyl groups having 2 to 4 carbon atoms, with allyl groups being particularly preferred. In the specification and claims of this application, "(meth)acryloyl group" means both an acryloyl group and a methacryloyl group. The curing agent (B) preferably has two or more groups selected from the group consisting of vinyl groups, allyl groups, and (meth)acryloyl groups.

[0039] Suitable specific examples of the curing agent (B) include triallyl cyanurate, triallyl isocyanurate (TAIC), trimethallyl isocyanurate, trimethylolpropane tri(meth)acrylate (2-ethyl-2-hydroxymethyl-1,3-propanediol tri(meth)acrylate), 1,3,5-triacryloylhexahydro-1,3,5-triazine, triallyl trimellitate, m-phenylenediamine bismaleimide, p-quinone dioxime, p,p'-dibenzoylquinone dioxime, dipropargyl terephthalate, diallyl phthalate, N,N',N'',N'''-tetraaryl terephthalamide, and vinyl group-containing polysiloxanes such as polymethylvinylsiloxane and polymethylphenylvinylsiloxane. Furthermore, allyl cyanurate derivatives (manufactured by Shikoku Chemicals, L-DAIC) are also preferred as curing agents (B). In the specification and claims of this application, "(meth)acrylate" refers to both acrylate and methacrylate.

[0040] Among these, one or more selected from the group consisting of triallyl cyanurate, triallyl isocyanurate, trimethylolpropane tri(meth)acrylate, and allyl cyanurate derivatives (manufactured by Shikoku Chemicals, L-DAIC) are more preferred. Particularly in terms of crosslinking reactivity, it is preferred that the curing agent (B) contains triallyl isocyanurate (TAIC) and / or trimethylolpropane tri(meth)acrylate (TMPTMA), and it is especially preferred that the curing agent (B) is TAIC.

[0041] The amount of curing agent (B) used is 2.5 to 30 parts by mass, more preferably 5 to 20 parts by mass, per 100 parts by mass of modified polyolefin (A). By using an amount of curing agent (B) within the above range, a liquid polyolefin composition is obtained that provides a cured product with excellent low dielectric properties and heat resistance.

[0042] <Initiator (C)> The liquid polyolefin composition contains an initiator (C). The initiator (C) is a component that promotes the crosslinking reaction between curing agents (B) or between curing agent (B) and modified polyolefin (A). Typically, any radical polymerization initiator can be used as initiator (C) without particular limitation. Initiator (C) may be used alone or in combination of two or more types.

[0043] Preferred examples of initiator (C) include peroxides such as benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, di-t-butyl peroxide, t-butylcumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumyl peroxide, di-t-butylperoxyisophthalate, t-butylperoxybenzoate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide, and trimethylsilyltriphenylsilyl peroxide. Initiator (C) is not limited to these peroxides. Among these, dicumyl peroxide and α,α'-bis(t-butylperoxy-m-isopropyl)benzene are preferred, and α,α'-bis(t-butylperoxy-m-isopropyl)benzene is more preferred. α,α'-bis(t-butylperoxy-m-isopropyl)benzene has a high reaction initiation temperature. For this reason, liquid polyolefin compositions containing α,α'-bis(t-butylperoxy-m-isopropyl)benzene as initiator (C) are easy to handle.

[0044] The 10-hour half-life temperature of initiator (C) is preferably 100°C or higher. Having a 10-hour half-life temperature of 100°C or higher suppresses the generation of gel-like foreign matter during film drying when forming a film using the liquid polyolefin composition. The 10-hour half-life temperature of initiator (C) can be determined by the following method. First, a solution of initiator (C) at a concentration of 0.1 mol / L or 0.05 mol / L is prepared using benzene as the solvent. Next, the initiator (C) solution is sealed in a nitrogen-purged glass tube. By immersing this glass tube in a constant temperature bath set to a predetermined temperature, the amount of decomposition of initiator (C) at a specific time can be measured. Generally, the decomposition of an initiator in a dilute solution can be treated as an approximate first-order reaction. If x is the amount of initiator (C) decomposed, k is the decomposition rate constant, t is the time, and a is the initial concentration of initiator (C), then the following equations (1) and (2) hold. dx / dt = k(ax) ... (1) ln a / (ax)=kt···(2) The half-life is the time it takes for the concentration of the initiator (C) to decrease to a / 2 due to decomposition. 1 / 2 Substituting a / 2 for x in equation (2), we obtain equation (3) below. kt 1 / 2 =ln 2···(3) Here, from equation (2), the thermal decomposition of the initiator (C) is performed at a specific temperature, and the relationship between time t and the value of ln a / (ax) is plotted on a coordinate plane. By obtaining an approximate straight line from the plotted data, the value of k can be obtained as the slope of the approximate straight line. On the other hand, with respect to the decomposition rate constant k, the following equations (4) and (5) hold true. k = A exp [-ΔE / RT] ... (4) ln k = ln A - ΔE / RT ... (5) Here, A, ΔE, R, and T are as follows: A: Frequency factor (1 / h) ΔE: Activation energy (J / mol) R: Gas constant (8.341 J / mol·K) T: Absolute temperature (K) By measuring the temperature k at several points, plotting the relationship between ln k and 1 / T on a coordinate plane, and obtaining an approximate straight line from the plotted data, the activation energy value can be obtained from the slope of the approximate straight line. Based on equation (3) above, eliminating k from equation (5) yields the following equation (6). ln t 1 / 2 =ΔE / RT-ln (A / 2)···(6) Then, for the temperature at several points, t 1 / 2 Measure ln t 1 / 2 By plotting the relationship between the value of and the value of 1 / T on a coordinate plane and obtaining an approximate straight line, the half-life of the initiator (C) at any temperature can be determined from this approximate straight line. From this approximate line, t 1 / 2 The value of temperature T at 10 hours is the 10-hour half-life temperature.

[0045] The 10-hour half-life temperature of the initiator (C) is preferably higher than the boiling point of the organic solvent (S) at atmospheric pressure, as described later. If the organic solvent (S) contains multiple types of organic solvents, the 10-hour half-life temperature of the initiator (C) is preferably lower than the lowest boiling point among the multiple types of organic solvents. By having a 10-hour half-life temperature of the initiator (C) higher than the boiling point of the organic solvent (S) at atmospheric pressure, the generation of gel-like foreign matter during film drying is suppressed when forming a film using the liquid polyolefin composition.

[0046] The amount of initiator (C) used is 0.5 to 2.7 parts by mass, more preferably 0.7 to 1.5 parts by mass, per 100 parts by mass of modified polyolefin (A). By using an amount of curing agent (B) within the above range, a liquid polyolefin composition is obtained that provides a cured product with excellent low dielectric properties and heat resistance.

[0047] Furthermore, the initiator (C) is preferably used such that the mass of the curing agent (B) is 5 to 30 times the mass of the initiator (C), and more preferably 7 to 20 times. By using the hardener (B) and initiator (C) in a ratio within the above range, crosslinking by the hardener (B) can be easily promoted without impairing the physical properties of the cured product.

[0048] <Organic solvent (S)> The liquid polyolefin composition contains an organic solvent (S). The type of organic solvent (S) is not particularly limited as long as it is soluble in the modified polyolefin (A), curing agent (B), and initiator (C).

[0049] Preferred examples of organic solvents (S) include hydrocarbon solvents and / or ether solvents. Specific examples of hydrocarbon solvents include chain aliphatic hydrocarbons having 5 to 16 carbon atoms, such as pentane, hexane, heptane, octane, nonane, decane, dodecane, and tetradecane; cyclic aliphatic hydrocarbons having 5 to 16 carbon atoms, such as methylcyclobutane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and cycloheptane; and aromatic hydrocarbons such as benzene, toluene, and xylene. Specific examples of ether solvents include linear aliphatic ethers with 4 to 16 carbon atoms such as diethyl ether, 1,2-dimethoxyethane, dipropyl ether, diisopropyl ether, dibutyl ether, and dihexyl ether; aromatic ethers with 7 to 16 carbon atoms such as dihexyl ether, anisole, phenethole, and methoxytoluene; and cyclic ethers with 3 to 16 carbon atoms such as furan, 2-methylfuran, tetrahydrofuran, tetrahydrofurfuryl alcohol, dioxol, dioxolane, pyran, dihydropyran, tetrahydropyran, dioxin, dioxene, dioxane, and trioxane.

[0050] The organic solvent (S) is used such that the ratio of the mass of components other than the organic solvent (S) in the liquid polyolefin composition to the mass of the liquid polyolefin composition is preferably 3 to 40% by mass, more preferably 8 to 25% by mass.

[0051] When the ratio of the mass of components other than the organic solvent (S) contained in the liquid polyolefin composition to the mass of the liquid polyolefin composition is within the above range, the liquid polyolefin composition has an appropriate viscosity, making it easy to mold the liquid polyolefin composition into the desired shape by methods such as casting or coating when curing it. In particular, when the content of modified polyolefin (A) in the liquid polyolefin composition is within the above range, it is easier to obtain a film with a uniform film thickness when manufacturing a film using the liquid polyolefin composition.

[0052] <Other resins> The liquid polyolefin composition may contain other resins besides modified polyolefin (A) as long as they do not hinder the objectives of the present invention. The ratio of the mass of modified polyolefin (A) to the total mass of the resin components contained in the liquid polyolefin composition is typically preferably 70% by mass, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 100% by mass.

[0053] Other examples of resins include unmodified polyolefins, modified polyolefins other than modified polyolefin (A), non-liquid crystal polyesters such as polyethylene terephthalate and polybutylene terephthalate, liquid crystal polyesters, polyamides, polyesteramides, polyimides, polyamide-imides, polycarbonates, polyacetals, polyphenylene sulfides, polyphenylene ethers, polysulfones, polyethersulfones, polyetherimides, silicone resins, and fluororesins.

[0054] <Inorganic fillers> Inorganic fillers may be added to the liquid polyolefin composition as needed. Examples of inorganic fillers include calcium carbonate, talc, clay, silica, magnesium carbonate, barium sulfate, titanium dioxide, alumina, montmorillonite, gypsum, glass flakes, glass fibers, milled glass fibers, carbon fibers, alumina fibers, silica-alumina fibers, aluminum borate whiskers, and potassium titanate fibers. Inorganic fillers may be used alone or in combination of two or more types.

[0055] The amount of these inorganic fillers used is determined appropriately according to the application of the cured product, within a range that does not impair the low dielectric properties of the cured product formed using the liquid polyolefin composition. For example, when forming a film using the liquid polyolefin composition, an upper limit is set for the amount of inorganic filler used, within a range that does not significantly impair the mechanical strength of the film.

[0056] <Additives> The liquid polyolefin composition may optionally contain various additives such as organic fillers, antioxidants, heat stabilizers, light stabilizers, flame retardants, lubricants, antistatic agents, colorants, rust inhibitors, crosslinking agents, foaming agents, fluorescent agents, surface smoothing agents, surface gloss improvers, and mold release improvers.

[0057] These additives may be used individually or in combination of two or more.

[0058] The liquid polyolefin composition described above yields a cured film that exhibits a peel strength of preferably 3.0 N / cm or higher, more preferably 5.0 N / cm or higher, and even more preferably 7.0 N / cm or higher, as measured by the following method consisting of steps 1) to 5). Curable compositions that yield cured films exhibiting such peel strength are suitably used in the manufacture of films that are laminated with metal foils such as copper foil. 1) A step of casting a liquid polyolefin composition onto a glass substrate. 2) A step of drying the cast liquid polyolefin composition by heating it at 50°C for 10 minutes, followed by heating it at 80°C for 30 minutes. 3) A step of peeling the film formed after drying from the glass substrate to obtain an uncured film. 4) The process involves sandwiching the uncured film between two electrolytic copper foils and pressing it at a press temperature of 180°C, a press pressure of 2.0 MPa, and a press time of 10 minutes to obtain a laminated film. 5) Using the obtained laminated film, measure the peel strength according to "6.5 Peel Strength" of JISC6471.

[0059] ≪Method for manufacturing hardened products≫ After molding the liquid polyolefin composition described above into the desired shape, a cured product is obtained by removing the organic solvent (S) and curing the mixture. Methods for molding liquid polyolefin compositions include, for example, casting and coating.

[0060] The above cured material exhibits excellent low dielectric properties in the high-frequency band. Specifically, the relative permittivity Dk at 10 GHz is 2.30 or less, and the dielectric loss tangent Df at 10 GHz is 0.0020 or less. Preferably, the relative permittivity Dk at 10 GHz is 2.20 or less, and preferably, the dielectric loss tangent Df at 10 GHz is 0.0017 or less.

[0061] The following describes a typical method for manufacturing a cured product, specifically a method for manufacturing a film made from a cured product. Specifically, the aforementioned liquid polyolefin composition is applied to a substrate to form a coating film, The process involves removing the organic solvent (S) from the coated film to obtain an uncured film, By curing the uncured film, a film made of cured material is obtained.

[0062] The substrate is not particularly limited as long as it is insoluble in organic solvents (S) and does not deteriorate or deform upon contact with organic solvents (S). Preferably, the substrate is made of a material that allows the formed film to be easily peeled off the substrate. Examples of substrates include paper, coated paper, nonwoven fabric, plastic film, glass substrate, ceramic substrate, and metal substrate.

[0063] The method for applying the liquid polyolefin composition onto a substrate is not particularly limited. Preferred application methods include using application equipment such as a roll coater, air knife coater, blade coater, rod coater, bar coater, comma coater, gravure coater, silkscreen coater, curtain flow coater, spray coater, dip coater, and spin coater. The thickness of the coating film formed by the coating process is not particularly limited and can be appropriately selected according to the thickness of the film.

[0064] The method for removing organic solvents (S) from the coating film is not particularly limited. Typically, the coating film may be heated to remove the organic solvents (S), or it may be removed by natural drying. The coating film may also be placed under a reduced pressure atmosphere to accelerate the removal of organic solvents (S). When removing organic solvents (S) by heating, the heating temperature is appropriately selected according to the boiling point of the organic solvent (S).

[0065] By curing the uncured film obtained in the manner described above, a film made of the cured liquid polyolefin composition described above is obtained. The film thickness is not particularly limited and is selected appropriately depending on the application of the film. Typically, the film thickness is preferably 5 to 500 μm, and more preferably 10 to 250 μm. The method for curing the uncured film is not particularly limited and is appropriately selected depending on the type of initiator (C). Specifically, curing methods include exposure and / or heating. Heating is preferred as the curing method because it is easier to obtain a well-cured film. When curing an uncured film by heating, the heating temperature is not particularly limited as long as the curing proceeds well. Typically, the heating temperature is preferably 100°C to 300°C, more preferably 120°C to 250°C, and even more preferably 140°C to 220°C. When curing the uncured film, pressure may be applied to the uncured film. The pressure applied to the uncured film is preferably 0.5 to 5.0 MPa, and more preferably 1.0 to 3.0 MPa. The heating time when heating the uncured film is not particularly limited as long as curing proceeds well. Typically, the heating time is preferably 1 minute to 1 hour, and more preferably 5 minutes to 30 minutes. [Examples]

[0066] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0067] [Manufacturing Example 1] (Manufacturing of modified α-olefin copolymers (graft-modified polyolefins)) 100 parts by mass of an α-olefin copolymer having a polymethylpentene-based structure (absorter EP1013, manufactured by Mitsui Chemicals) and 0.15 parts by mass of (b1) 1,3-di(tert-butylperoxyisopropyl)benzene (Perbutyl P, manufactured by NOF Corporation) were supplied from the hopper opening to a twin-screw extruder (46 mmφ, L / D=63, manufactured by Kobe Steel, Ltd.) set to a cylinder temperature of 200°C and a screw rotation speed of 150 rpm for melt mixing. During this process, 1 part by mass of styrene and 1 part by mass of glycidyl methacrylate were added midway through the cylinder. Subsequently, pellets of graft-modified polyolefin A1 were obtained by vacuum evaporation from the vent opening.

[0068] The obtained resin pellets were dissolved in xylene at 130°C, and then recrystallized resin precipitated upon cooling to room temperature. The amount of glycidyl methacrylate modification was measured using a potentiometric automatic titrator (Kyoto Electronics Manufacturing Co., Ltd. AT700) in accordance with JIS K7236. The amount of glycidyl methacrylate modification in graft-modified polyolefin A1 was 0.23% by mass.

[0069] [Manufacturing Example 2] 100 parts by mass of polymethylpentene (TPX grade MX002, manufactured by Mitsui Chemicals) and 0.25 parts by mass of (b1) 1,3-di(tert-butylperoxyisopropyl)benzene (Perbutyl P, manufactured by NOF Corporation) were supplied from the hopper opening to a twin-screw extruder (46 mmφ, L / D=63, manufactured by Kobe Steel, Ltd.) set to a cylinder temperature of 230°C and a screw rotation speed of 150 rpm for melt mixing. During this process, 1 part by mass of styrene and 1 part by mass of glycidyl methacrylate were added midway through the cylinder. Graft-modified polyolefin A2 pellets were then obtained by vacuum evaporation from the vent opening. The amount of glycidyl methacrylate modification in the obtained resin pellets was measured in the same manner as in Production Example 1. The amount of glycidyl methacrylate modification in the graft-modified polyolefin A2 was 0.34% by mass.

[0070] [Examples 1-10 and Comparative Examples 1-6] In the examples and comparative examples, the following A1 to A4 were used as polyolefins. A1: Graft-modified polyolefin obtained in Production Example 1 A2: Graft-modified polyolefin obtained in Production Example 2 A3: α-olefin copolymer (Mitsui Chemicals Absorter EP1013) A4: Polymethylpentene (Mitsui Chemicals TPX grade MX002) 1

[0071] In the examples and comparative examples, the following B1 to B3 were used as curing agents. B1: Triallyl isocyanurate B2: Allyl cyanurate derivative (manufactured by Shikoku Chemicals Co., Ltd., L-DAIC, N-alkyldiallyl isocyanurate) B3: Trimethylolpropane tri(meth)acrylate (2-ethyl-2-hydroxymethyl-1,3-propanediol tri(meth)acrylate)

[0072] In the examples and comparative examples, the following C1 and C2 were used as initiators. C1: α,α'-Bis(t-butylperoxy-m-isopropyl)benzene (manufactured by Nippon Oil & Fats Co., Ltd., Perbutyl® P) C2: Dicumyl peroxide (manufactured by Nippon Oil & Fats Co., Ltd., Perkmyl® D)

[0073] Polyolefin solutions were obtained by dissolving the types and quantities (parts by mass) of polyolefins listed in Tables 1 to 3 in a mixed solvent consisting of 50% by mass of cyclopentane and 50% by mass of tetrahydrofuran, so that the concentration of the polyolefin was 12% by mass. The resulting polyolefin solution was used to dissolve the curing agent and initiator of the types and amounts listed in Tables 1 to 3 to produce a liquid polyolefin composition.

[0074] Using the liquid polyolefin compositions obtained for each example and each comparative example, films were prepared according to the following method. Furthermore, the curability of the liquid polyolefin composition was evaluated according to the following method. The dielectric properties, peel strength, and appearance after reflow were evaluated for the obtained films according to the following method. The evaluation results are shown in Tables 1 to 3. In the case of Comparative Example 4, only a very brittle film was obtained using the liquid polyolefin composition, so the dielectric properties, peel strength, and appearance after reflow were not evaluated.

[0075] [Hardening evaluation] The liquid polyolefin compositions of each example and comparative example were cast onto a glass substrate. The cast liquid polyolefin compositions were then dried by heating at 50°C for 10 minutes, followed by heating at 80°C for 30 minutes. The resulting film was peeled off the glass substrate to obtain an uncured film. The uncured film was heat-treated and cured under the conditions of a press temperature of 180°C, a press pressure of 2.0 MPa, and a press time of 10 minutes to obtain a cured film with a thickness of 50 μm. A rectangular test piece measuring 5 mm x 10 mm was cut from the obtained cured film. The test piece was immersed in a mixed solvent consisting of 50% by mass of cyclopentane and 50% by mass of tetrahydrofuran at room temperature for 24 hours. If the film remained intact after immersion while retaining its shape, it was judged as curable (○). If the film's shape was not retained after immersion, it was judged as curable (×).

[0076] [Dielectric properties (relative permittivity, dielectric loss tangent)] A cavity resonator perturbation method complex dielectric constant evaluation apparatus was used as the measurement device, and the relative permittivity and dielectric loss tangent of the film obtained at the following frequencies were measured. The relative permittivity and dielectric loss tangent of the obtained cured film were measured using a Hewlettpackard 8719C network analyzer and a Kanto Electronics Applied Development Co., Ltd. CP511 cavity resonator vibration method dielectric constant measurement device. For the measurement of relative permittivity and dielectric loss tangent, strip-shaped test pieces measuring 2 mm × 100 mm, cut from the cured film obtained using the same method as for curability evaluation, were used. The measurement conditions were as follows. Measurement frequency: 10GHz Measurement conditions: temperature 23℃, humidity 50%RH Measurement sample: A sample that had been left standing for 24 hours under the above measurement conditions was used.

[0077] [Peel strength] For curing evaluation, the uncured film obtained using the method described above was sandwiched between two electrolytic copper foils (CF-T49A-DS-HD2-12 (manufactured by Fukuda Metal Foil & Powder Industry Co., Ltd.)), and pressed at a press temperature of 180°C, a press pressure of 2.0 MPa, and a press time of 10 minutes to obtain a laminated film. The peel strength of the obtained laminated film was measured according to JISC6471 "6.5 Peel Strength". Specifically, a 1 mm wide metal foil portion was peeled at a peel angle of 90 degrees and a peeling speed of 100 mm / min, and the load was measured. The measured load value was defined as the peel strength.

[0078] [Appearance after reflow] Laminated films obtained using the same method as for measuring peel strength were passed through a high-temperature reflow oven (Antom Corporation, UNI6116S), and the laminated films were observed after passing through the high-temperature reflow oven. The conditions for passing the material through the high-temperature reflow oven are a peak temperature of 288±3°C, a passage time of 60 seconds, and 3 passage cycles. A "○" rating was given if there was no change in the appearance of the laminated film after passing through the high-temperature reflow oven. A "×" rating was given if there was a change in the appearance of the laminated film after passing through the high-temperature reflow oven. Changes in appearance include, for example, wrinkles, the appearance of irregularities other than wrinkles, and delamination of the copper foil.

[0079] [Table 1]

[0080] [Table 2]

[0081] [Table 3]

[0082] Tables 1 and 2 show that the liquid polyolefin composition of the example, comprising a modified polyolefin (A), which is a chain-like polyolefin modified with a monomer having a polar group, a curing agent (B) in the predetermined range mentioned above, an initiator (C) in the predetermined range mentioned above, and an organic solvent (S), cures well and provides a film with excellent dielectric properties and heat resistance. On the other hand, Table 3 shows that when comparative examples of liquid polyolefin compositions are used that contain only unmodified linear polyolefins, or that do not contain the curing agent (B) or the initiator (C) within the predetermined range mentioned above, curing may not proceed well, a film with a high dielectric constant may be formed, or a film with poor heat resistance may be formed.

Claims

1. It comprises a modified polyolefin (A), a curing agent (B), an initiator (C), and an organic solvent (S), The modified polyolefin (A) is a chain-like polyolefin modified with a monomer having a polar group. The curing agent (B) has two or more groups selected from the group consisting of vinyl groups, allyl groups, and (meth)acryloyl groups. The content of the curing agent (B) is 2.5 to 30 parts by mass per 100 parts by mass of the modified polyolefin (A). A liquid polyolefin composition in which the amount of the initiator (C) is 0.5 to 2.7 parts by mass per 100 parts by mass of the modified polyolefin (A).

2. The liquid polyolefin composition according to claim 1, wherein the mass of the curing agent (B) is 5 to 30 times the mass of the initiator (C).

3. The liquid polyolefin composition according to claim 1 or 2, wherein the organic solvent (S) comprises a hydrocarbon solvent and / or an ether solvent.

4. The liquid polyolefin composition according to any one of claims 1 to 3, wherein the ratio of the mass of components other than the organic solvent (S) contained in the liquid polyolefin composition to the mass of the liquid polyolefin composition is 3 to 40% by mass.

5. The liquid polyolefin composition according to any one of claims 1 to 4, wherein the 10-hour half-life temperature of the initiator (C) is 100°C or higher.

6. The liquid polyolefin composition according to any one of claims 1 to 5, wherein the 10-hour half-life temperature of the initiator (C) is higher than the boiling point of the organic solvent (S) at atmospheric pressure.

7. The liquid polyolefin composition according to any one of claims 1 to 6, wherein the amount of modification of the modified polyolefin (A) by a monomer having a polar group is 0.05 to 1.50% by mass.

8. The liquid polyolefin composition according to any one of claims 1 to 7, wherein the modified polyolefin (A) comprises polymethylpentene modified with a monomer having a polar group.

9. The liquid polyolefin composition according to any one of claims 1 to 8, wherein the ratio of the mass of the modified polyolefin (A) to the total mass of the resin components contained in the liquid polyolefin composition is 50% by mass or more.

10. A liquid polyolefin composition according to any one of claims 1 to 9, which gives a cured film exhibiting a peel strength of 3.0 N / cm or more as measured by a method consisting of the following steps 1) to 5). 1) A step of casting the liquid polyolefin composition onto a glass substrate. 2) A step of drying the cast liquid polyolefin composition by heating it at 50°C for 10 minutes, followed by heating it at 80°C for 30 minutes. 3) A step of peeling the film formed after drying from the glass substrate to obtain an uncured film. 4) The process of sandwiching the uncured film between two electrolytic copper foils and pressing it at a press temperature of 180°C, a press pressure of 2.0 MPa, and a press time of 10 minutes to obtain a laminated film. 5) A step of measuring the peel strength using the obtained laminated film according to "6.5 Peel Strength" of JIS C6471.

11. A cured product of the liquid polyolefin composition according to claims 1 to 10.

12. The cured product according to claim 11, wherein the relative permittivity Dk at 10 GHz is 2.30 or less, and the dielectric loss tangent Df at 10 GHz is 0.0020 or less.

13. A film comprising the cured product according to claim 11 or 12.

14. A liquid polyolefin composition according to any one of claims 1 to 10 is applied to a substrate to form a coating film, The organic solvent (S) is removed from the coated film to obtain an uncured film. A method for manufacturing a film, comprising curing the aforementioned uncured film.

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