Films for communication boards and communication equipment

Abstract

The present invention aims to provide a communication substrate film having low dielectric properties, excellent UV laser processability, and suppressed bleed-out of ultraviolet absorbers. [Solution] The present invention relates to a film for communication substrates comprising a non-polar resin and a triazine-based ultraviolet absorber, wherein the absorbance at a wavelength of 355 nm per 10 μm thickness is 1.0 or more. The present invention also relates to a communication device equipped with a film for communication substrates.

Description

[Technical Field]

[0001] This invention relates to a film for communication substrates and communication equipment. [Background technology]

[0002] Polyolefin resins, being non-polar resins, possess excellent mechanical properties (bending properties, tensile properties, etc.), low dielectric properties, chemical resistance, and moldability. Due to their low specific gravity and low cost, they are used in a wide range of applications, including machinery, electrical and electronic equipment, office automation equipment, automotive interior and exterior materials, and electric vehicles.

[0003] In order to impart ultraviolet absorption properties to polyolefin resins, ultraviolet absorbers are added. For example, Patent Document 1 discloses a polypropylene resin film obtained by melt-extruding a propylene resin composition containing a propylene resin and a triazine ultraviolet absorber, and then heat-treating the film at a temperature of 50°C or higher and below the main melting peak temperature of the propylene resin composition.

[0004] In recent years, the development of communication technologies utilizing high-frequency (GHz) electromagnetic waves has accelerated in order to realize high-speed, high-capacity communication, and the development of communication equipment that utilizes high-frequency electromagnetic waves is progressing. However, it is known that transmission loss increases as the frequency of electromagnetic waves increases. For this reason, there is a need to develop materials that exhibit low dielectric properties in order to reduce the transmission loss of components that make up high-frequency communication equipment. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2012-162643 [Overview of the project] [Problems that the invention aims to solve]

[0006] In conventional technology, when an ultraviolet absorber was added to a resin film, the ultraviolet absorber would bleed out of the propylene-based resin film, causing the film to whiten, which was a problem.

[0007] Furthermore, while UV lasers are sometimes used to process resin films, polyolefin resins lack functional groups that absorb ultraviolet light, making them unsuitable for processing such as cutting using UV lasers. To address this, carbon compounds such as fullerenes and carbon black are sometimes added to absorb ultraviolet light, but these are conductive and therefore unsuitable for communication equipment applications where low dielectric properties are required.

[0008] Therefore, in order to solve the problems of the conventional technology, the present inventors have conducted research with the aim of providing a communication substrate film having low dielectric properties, excellent UV laser processability, and suppressed bleed-out of ultraviolet absorbers. [Means for solving the problem]

[0009] Examples of specific embodiments of the present invention are shown below.

[0010] [1] A film for communication substrates comprising a nonpolar resin and a triazine-based ultraviolet absorber, wherein the absorbance at a wavelength of 355 nm per 10 μm thickness is 1.0 or higher. [2] The film for communication substrates according to [1], wherein the content of the triazine-based ultraviolet absorber per 100 parts by mass of the nonpolar resin is 1 to 10 parts by mass. [3] A film for communication substrates according to [1] or [2], wherein the absorbance of the triazine-based ultraviolet absorber at a wavelength of 355 nm is 0.5 or higher. [4] A film for communication substrates according to any one of [1] to [3], wherein the triazine-based ultraviolet absorber is a compound represented by the following formula (1). [ka] (In formula (1), R 1~R 3 Each of these independently represents an alkyl group having 1 to 12 carbon atoms, and R 4 ~R 6 Each of these independently represents a hydrogen atom, an alkyl group with 1 to 5 carbon atoms, or a hydroxyl group. [5] A film for a communication substrate according to any one of [1] to [4], wherein the nonpolar resin is at least one selected from the group consisting of propylene resin, ethylene resin, cyclic olefin resin, styrene resin, and polymethylpentene. [6] A film for communication substrates according to any of [1] to [5], wherein the dielectric constant at a frequency of 10 GHz, a temperature of 23°C, and a relative humidity of 50% is 3.0 or less. [7] A film for communication substrates according to any of [1] to [6], wherein the dielectric loss tangent at a frequency of 10 GHz, a temperature of 23°C, and a relative humidity of 50% is 0.0010 or less. [8] A communication device equipped with a communication board film as described in any of [1] to [7]. [Effects of the Invention]

[0011] According to the present invention, it is possible to obtain a communication substrate film having low dielectric properties, excellent UV laser processability, and suppressed bleed-out of ultraviolet absorbers. Furthermore, according to the present invention, it is possible to provide communication equipment including such a film. [Modes for carrying out the invention]

[0012] Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be based on typical embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, when expressed as "X to Y" (X and Y are arbitrary numbers), unless otherwise specified, it means "X or more and Y or less", and also includes the meaning of "preferably larger than X" or "preferably smaller than Y". Further, when expressed as "X or more" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number), it also includes the intention of "preferably larger than X" or "preferably less than Y". In the following description, "film" and "sheet" are not clearly distinguished, and when referred to as "film", it includes "sheet", and when referred to as "sheet", it includes "film".

[0013] (Film for communication substrate) This embodiment relates to a film for a communication substrate (hereinafter also referred to as this film) that contains a non-polar resin and a triazine-based ultraviolet absorber and has an absorbance at a wavelength of 355 nm of 1.0 or more per 10 μm in thickness. Since this embodiment has the above configuration, it is possible to obtain a film for a communication substrate having low dielectric characteristics, excellent UV laser processability, and suppressed bleed-out of the ultraviolet absorber.

[0014] The absorbance at the wavelength of 355 nm described above is the absorbance when the film thickness is converted to 10 μm. When the film thickness is 10 μm, the absorbance at a wavelength of 355 nm of the film is measured, and the measured value is directly the absorbance at a wavelength of 355 nm per 10 μm in thickness. On the other hand, when the film thickness is greater than 10 μm, after the film is thermally pressed to a film with a thickness of about 10 μm, the absorbance is measured. Then, by converting the measured absorbance value per 10 μm, the absorbance at a wavelength of 355 nm per 10 μm in thickness is obtained. When the thickness of the film after thermal pressing becomes 10 μm, the measured value after thermal pressing is directly the absorbance at a wavelength of 355 nm per 10 μm in thickness.

[0015] In this embodiment, the content of triazine-based ultraviolet absorber per 100 parts by mass of nonpolar resin is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more. Furthermore, the content of triazine-based ultraviolet absorber per 100 parts by mass of nonpolar resin is preferably 10 parts by mass or less. Normally, ultraviolet absorbers are added to improve UV weather resistance, and the amount added is less than 1 part by mass. Also, if the amount of ultraviolet absorber added is increased, it becomes easier for it to bleed out from the film, causing the film to whiten. For this reason, in conventional technology, the content of triazine-based ultraviolet absorber has not been set above the above lower limit. On the other hand, since this embodiment is a resin film used for communication substrate applications, it is required to have laser processability such as the ability to drill holes, and the triazine-based ultraviolet absorber is added not to improve UV weather resistance, but to improve UV laser processability. For this reason, the amount of triazine-based ultraviolet absorber added is higher than the amount added in a normal resin film. In this embodiment, by setting the content of the triazine-based ultraviolet absorber to above the lower limit, excellent UV laser processability is obtained. Thus, the resin film of this embodiment has excellent laser processability when processed into a communication substrate and is preferably used as a film for communication substrates. Furthermore, in this embodiment, by setting the content of the triazine-based ultraviolet absorber to below the upper limit, it becomes easier to suppress the bleeding out of the ultraviolet absorber.

[0016] Typically, the wavelength of laser light used in UV laser processing is between 350 and 370 nm. In this embodiment, by setting the absorbance at a wavelength of 355 nm to 1.0 or higher per 10 μm thickness of the communication substrate film, the film can efficiently absorb laser light. The film surface that absorbs the laser light is locally heated and melted in a short time, effectively improving UV laser processability. Thus, by efficiently absorbing light at a wavelength of 355 nm, the laser processability, such as drilling holes, can be enhanced in this film.

[0017] The absorbance of this film at a wavelength of 355 nm per 10 μm thickness is preferably 1.0 or more, more preferably 1.2 or more, still more preferably 1.5 or more, even more preferably 1.8 or more, and particularly preferably 2.0 or more. Also, the upper limit value of the absorbance of this film at a wavelength of 355 nm per 10 μm thickness is not particularly limited, and for example, it may be 10.0. By setting the absorbance of this film at a wavelength of 355 nm per 10 μm thickness within the above range, the film can efficiently absorb laser light, and the surface portion of the film that has absorbed the laser light is locally heated and melted in a short time. As a result, the laser processing performance can be enhanced more effectively.

[0018] In this specification, the laser processing performance can be evaluated by cutting performance into a predetermined shape in addition to the drilling performance. In the evaluation of the laser processing performance, after performing drilling (through-hole forming) or cutting, it is also evaluated whether the unnecessary portion is separated. In this embodiment, after performing drilling or cutting, a state where the unnecessary portion is completely separated can be determined to have good laser processing performance.

[0019] Also, in this embodiment, by blending a triazine-based ultraviolet absorber that absorbs at a wavelength of 355 nm, it is possible to suppress the bleed-out of the ultraviolet absorber. In this embodiment, even when placed in a high-temperature and high-humidity environment (85 °C, 85% relative humidity environment) for a long time, the bleed-out of the ultraviolet absorber can be suppressed.

[0020] This film is a film for a communication substrate, and it is preferably a film used for a substrate of a communication device that uses electromagnetic waves in a high-frequency (GHz) band. Therefore, low dielectric characteristics are required for this film. Specifically, the relative permittivity of this film at a frequency of 10 GHz, a temperature of 23°C, and a relative humidity of 50% is preferably 3.0 or less, more preferably 2.8 or less, and even more preferably 2.6 or less. The lower limit of the relative permittivity of this film at a frequency of 10 GHz, a temperature of 23°C, and a relative humidity of 50% is not particularly limited and may be, for example, 1.0. By setting the relative permittivity of this film within the above range, dielectric loss is reduced, the transmission efficiency of electrical signals on the circuit board is improved, and higher speeds become possible. The lower the relative permittivity, the faster the signal speed becomes, approaching the speed of light. Therefore, by using this film with a relative permittivity within the above range, it is possible to increase the signal speed in high-frequency circuits, for example.

[0021] Furthermore, the dielectric loss tangent of this film at a frequency of 10 GHz, a temperature of 23°C, and a relative humidity of 50% is preferably 0.0010 or less, more preferably 0.0008 or less, and even more preferably 0.0007 or less. The lower limit of the dielectric loss tangent of this film at a frequency of 10 GHz, a temperature of 23°C, and a relative humidity of 50% is not particularly limited and may be, for example, 0.00001. Dielectric loss tangent is an indicator of electrical energy loss within an insulator, and is a value determined from the ratio of the current being charged to the current being lost. In an ideal insulator, electrical energy loss is zero, so a small dielectric loss tangent is desirable. In particular, in high-frequency circuit boards, power absorption causes signal transmission loss and is converted into heat. Dielectric loss tangent affects the quality of signal transmission; therefore, the larger the dielectric loss tangent, the greater the absorption and signal loss, and conversely, the lower the dielectric loss tangent, the less signal loss. Furthermore, by setting the dielectric loss tangent of this film within the above range, the transmission efficiency of electrical signals on the circuit board can be improved, and even higher speeds can be achieved.

[0022] The relative permittivity and dielectric loss tangent of this film were measured using the cavity resonator method in accordance with JIS C2565:1992, under conditions of 23°C, 40% relative humidity, and 10 GHz frequency.

[0023] This film may be a single layer or a multi-layer structure. Furthermore, this film may be an unstretched film, a uniaxially oriented film, or a biaxially oriented film. However, from the viewpoint of secondary processing, an unstretched film is preferred.

[0024] The thickness of this film is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. Furthermore, the thickness of this film is preferably 500 μm or less, more preferably 400 μm or less, and even more preferably 300 μm or less. By setting the thickness of this film within the above range, the processability and handling properties during the manufacturing of communication substrates can be more effectively improved.

[0025] (Non-polar resin) This film contains a non-polar resin. In this specification, a non-polar resin refers to a resin whose molecular main chain is mainly composed of carbon atoms and hydrogen atoms. However, resins containing a low proportion of polar molecules in their molecules are also included in the definition of a non-polar resin. "Low proportion" means that the content of polar molecules (polar groups) is 1.0% by mass or less.

[0026] Examples of nonpolar resins include polyolefin resins, styrene resins, naphthalene resins, fluororesins, and silicone resins. The nonpolar resin is preferably a polyolefin resin or a styrene resin, and more preferably at least one selected from the group consisting of propylene resin, ethylene resin, cyclic olefin resin, styrene resin, polymethylpentene, and polymethylbutene. Examples of styrene resins include polystyrene, syndiotactic polystyrene, polystyrene derivatives, and copolymers of styrene.

[0027] The nonpolar resin is preferably a polyolefin resin. Examples of polyolefin resins include homopolymers of olefins, interpolymers, and copolymers with other copolymerizable monomers (e.g., other vinyl monomers). Specifically, examples of polyolefins include polyethylene (LDPE, LLDPE, etc.), polypropylene, polybutene, interpolymers thereof, and ionomer resins. In addition, cyclic olefin resins and methylpentene resins can also be used as polyolefin resins. Among these, the nonpolar resin is more preferably at least one selected from propylene resins and cyclic olefin resins, and is particularly preferably a propylene resin. By using the above resins as the nonpolar resin, it becomes easier to obtain a communication substrate film with low dielectric properties.

[0028] When the nonpolar resin is polypropylene, examples of polypropylene include homopolypropylene (propylene homopolymer), random copolymers or block copolymers of propylene with ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, or 1-decene (all α-olefins). When the nonpolar resin is polypropylene, it is more preferable that it contains 50 mol% or more of propylene units as constituent monomer units, even more preferable that it contains 60 mol% or more, even more preferable that it contains 70 mol% or more, even more preferable that it contains 80 mol% or more, and particularly preferable that it contains 90 mol% or more. It is also preferable that the nonpolar resin contains 100 mol% of propylene units as constituent monomer units. In other words, it is preferable that the nonpolar resin is homopolypropylene (propylene homopolymer).

[0029] When the nonpolar resin is polypropylene, the isotactic pentad fraction exhibiting stereoregularity is preferably 80% to 99%, more preferably 83% to 98%, and even more preferably 85% to 97%. The isotactic pentad fraction refers to the stereostructure or ratio in which the five methyl groups of the side chains are all located in the same direction relative to the main chain composed of five carbon-carbon bonds consisting of any five consecutive propylene units. The assignment of the methyl group region signal is in accordance with A. Zambelli et al. (Macromol. 8, 687 (1975)). If the isotactic pentad fraction of the nonpolar resin is above the lower limit above, good mechanical strength is more likely to be obtained. Note that the upper limit of the isotactic pentad fraction is currently defined as the upper limit industrially obtainable, but this may not apply if resins with even higher regularity are developed at an industrial level in the future.

[0030] When the nonpolar resin is a methylpentene-based resin, it is preferable that the methylpentene-based resin is a homopolymer or copolymer of pentene compounds such as 4-methyl-1-pentene and 3-methyl-1-pentene. Specifically, the methylpentene-based resin is preferably a copolymer with ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, etc., with 4-methyl-1-pentene as the main component.

[0031] When the nonpolar resin is a cyclic olefin resin, the cyclic olefin resin may be amorphous or crystalline. When the cyclic olefin polymer is amorphous, the glass transition temperature of the cyclic olefin polymer is preferably 80°C or higher, more preferably 100°C or higher, and even more preferably 120°C or higher. Furthermore, the glass transition temperature of the cyclic olefin polymer is preferably 250°C or lower, more preferably 230°C or lower, and even more preferably 200°C or lower. By setting the glass transition temperature of the cyclic olefin polymer within the above range, the heat resistance of the film for communication substrates can be improved.

[0032] If the nonpolar resin has a melting point, it is preferably 130°C or higher, more preferably 140°C or higher, and even more preferably 150°C or higher. While there is no particular upper limit to the melting point of the nonpolar resin, from the viewpoint of processability, it is preferably, for example, 300°C or lower. By setting the melting point of the nonpolar resin within the above range, the heat resistance of the film for communication substrates can be improved.

[0033] The molecular weight distribution parameter Mw / Mn of a nonpolar resin is preferably between 1.5 and 10.0, more preferably between 1.8 and 8.0, and even more preferably between 2.0 and 6.0. A smaller Mw / Mn value indicates a narrower molecular weight distribution. Setting Mw / Mn above the lower limit of the above-mentioned value allows for good extrusion moldability and facilitates large-scale industrial production. On the other hand, setting Mw / Mn below the upper limit of the above-mentioned value makes it easier to obtain sufficient mechanical strength. Mw / Mn is measured as a polystyrene equivalent value by GPC (gel per emission chromatography).

[0034] The melt flow rate (MFR) of the nonpolar resin is not particularly limited, but is preferably 0.5 g / 10 min to 30 g / 10 min, and more preferably 1.0 g / 10 min to 20 g / 10 min. The melt flow rate (MFR) is measured in accordance with JIS K7210-1:2014, and is measured at 230°C and a 2.16 kg load when the nonpolar resin is polypropylene, at 280°C and a 2.16 kg load when the nonpolar resin is a cyclic olefin polymer, and at 260°C and a 5 kg load when the nonpolar resin is a methylpentene polymer. By setting the MFR of the nonpolar resin to be above the lower limit, sufficient melt viscosity can be achieved during molding, making it easier to ensure high productivity. Furthermore, by setting the MFR of the nonpolar resin to be below the upper limit, it becomes easier to ensure sufficient strength.

[0035] The content of the nonpolar resin is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on the total mass of the film. Furthermore, the content of the nonpolar resin may be 100% by mass or less than 99% by mass, based on the total mass of the film. By setting the content of the nonpolar resin within the above range, it becomes easier to obtain a film with excellent low dielectric properties.

[0036] (Triazine-based UV absorber) This film contains a triazine-based ultraviolet absorber. The absorbance of the triazine-based ultraviolet absorber at a wavelength of 355 nm, measured using a 1 cm wide cell after dissolving it in a toluene solution to a concentration of 10 mg / kg, is preferably 0.5 or higher, more preferably 0.55 or higher, and even more preferably 0.6 or higher. Furthermore, the upper limit of the absorbance of the triazine-based ultraviolet absorber at a wavelength of 355 nm is not particularly limited and may be, for example, 10.0. By setting the absorbance of the triazine-based ultraviolet absorber used in this embodiment at a wavelength of 355 nm to be above the lower limit, the UV laser processability can be more effectively improved.

[0037] As the triazine-based ultraviolet absorber, it is preferable to use a compound represented by the following formula (1). [ka]

[0038] In formula (1), R 1 ~R 3 Each substituent is preferably independently composed of at least one atom selected from the group consisting of carbon atoms, oxygen atoms, and nitrogen atoms, more preferably a substituent containing a carbon atom, even more preferably an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a heteroaliphatic ring group, or a heteroaromatic ring group, and even more preferably an aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched, or cyclic. Furthermore, the aliphatic hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. Among these, R 1 ~R3 It is preferably an alkyl group independently, more preferably an alkyl group having 1 to 12 carbon atoms, and particularly preferably an alkyl group having 1 to 10 carbon atoms. In the present specification, the alkyl group includes a branched alkyl group and a cyclic alkyl group in addition to the linear alkyl group.

[0039] In formula (1), R 4 ~R 6 is preferably a hydrogen atom or a substituent containing at least one selected from the group consisting of a carbon atom, an oxygen atom, and a nitrogen atom independently. When R 4 ~R 6 are each independently a substituent containing a carbon atom, the substituent containing a carbon atom is more preferably an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a heteroaliphatic ring group, or a heteroaromatic ring group, and even more preferably an aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched, or cyclic. Among them, R 4 ~R 6 are preferably a hydrogen atom, an alkyl group, or a hydroxy group independently, more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a hydroxy group, even more preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a hydroxy group, and particularly preferably a hydrogen atom or a hydroxy group.

[0040] Specific examples of the triazine-based ultraviolet absorber include the following compounds. The following compounds are, in order, bemotrizinol, 2,4,6-tris(4-butoxy-2-hydroxyphenyl)-1,3,5-triazine, and 6-(2,4-bis(butyloxyphenyl))-1,3,5-triazine. Among them, the triazine-based ultraviolet absorber is preferably bemotrizinol. By using bemotrizinol as the triazine-based ultraviolet absorber, it is possible to effectively suppress the bleed-out of the ultraviolet absorber even in a high-temperature and high-humidity environment.

[0041]

Chemical formula

[0042] The content of the triazine-based ultraviolet absorber per 100 parts by mass of nonpolar resin is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more. Furthermore, the content of the triazine-based ultraviolet absorber per 100 parts by mass of nonpolar resin is preferably 10 parts by mass or less. In this embodiment, by setting the content of the triazine-based ultraviolet absorber to above the above lower limit, excellent UV laser processability can be obtained. Thus, the resin film of this embodiment has excellent laser processability when processed into a communication substrate and is preferably used as a film for communication substrates.

[0043] (Other ingredients) This film may contain additives in addition to a non-polar resin and a triazine-based ultraviolet absorber, as needed. Examples of additives include inorganic fillers, organic fillers, heat stabilizers, light stabilizers, ultraviolet stabilizers, nucleating agents, flame retardants, plasticizers, weathering agents, antioxidants, lubricants, antistatic agents, colorants, and conductive agents. The additive content is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, based on the total mass of the film.

[0044] Furthermore, this film may contain other resins in addition to the non-polar resin described above. Examples of other resins include modified polyolefins and polyester resins. Examples of modified polyolefins include silane-modified polyolefins, acid-modified polyolefins, copolymers of olefins and other polar monomers, and polyolefins modified with halogen elements. In this case, the content of the modifying group in the modified polyolefin is greater than 1.0% by mass. Examples of polyester resins include polyethylene terephthalate (PET) or liquid crystal polymer (LCP).

[0045] The content of other resins is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, relative to the total mass of resins contained in the film. Including modified polyolefins or polyester resins as the other resins makes it easier to obtain a film with excellent adhesion to metal bodies such as copper foil and other substrates, as well as excellent heat resistance, while maintaining low dielectric properties.

[0046] (Method of manufacturing film for communication boards) This film can be manufactured by drying a resin composition containing the aforementioned non-polar resin and triazine-based ultraviolet absorber as needed, then feeding it into an extruder for melt-kneading, extruding the molten resin composition through the extruder into a film (sheet) form using a T-die, and then cooling and solidifying it, for example, by adhering it to a cooling roll. Alternatively, the triazine-based ultraviolet absorber may be pre-mixed into the resin and diluted as needed during film formation. While the film for communication substrates is preferably an unstretched film, it may be stretched as needed.

[0047] (Revolving body) This embodiment may also be a wound body (film roll) formed by winding the above-described communication board film into a roll shape. When winding the communication board film, it is preferable to wind the communication board film onto a core. It is preferable to use a core that has a width equal to or greater than the width of the communication board film.

[0048] A core is a cylindrical winding core used for winding film. The material of the core is not particularly limited, but examples include paper, resin-impregnated paper, acrylonitrile-butadiene-styrene copolymer (ABS resin), FRP, phenolic resin, and inorganic-containing resin. Among these, it is preferable that the core be made of a resin such as acrylonitrile-butadiene-styrene copolymer (ABS resin), FRP, phenolic resin, or inorganic-containing resin, from the viewpoint of having a small coefficient of thermal expansion, high rigidity, low swelling with respect to humidity, and excellent winding properties. When the core material is paper, the desired properties can be easily obtained by coating its surface with a resin or the like. Furthermore, from the viewpoint of surface smoothness, it is also preferable that the core be a tube made of resin-impregnated paper.

[0049] The length of the communication substrate film in the wound body (winding length) is not particularly limited, but is preferably 5m or more, more preferably 10m or more, and even more preferably 50m or more. Furthermore, the length of the communication substrate film is preferably 10,000m or less.

[0050] (Communication equipment components and equipment) This embodiment may also be a communication equipment component having a configuration in which the above-described communication substrate film and an adherend such as a conductor are in contact. The conductor is preferably a metal conductor, and examples of metals constituting the conductor include copper, aluminum, zinc, titanium, nickel, and alloys containing any of these. The surface of the conductor may also be plated. Examples of conductor shapes include plate-like, foil-like, and wire-like shapes.

[0051] This embodiment may also be a communication device equipped with the communication substrate film described above. Examples of communication devices include mobile phones, PHS phones, smartphones, tablets (tablet computers), mobile computers (mobile PCs), personal digital assistants (PDAs), antennas, base stations, etc. Other examples of communication devices include IoT (Internet of Things) terminals and other devices with edge computing capabilities. In particular, the film for communication equipment of this embodiment exhibits low dielectric properties and is therefore preferably used in communication equipment that utilizes electromagnetic waves in the high-frequency band. By using the film for communication equipment of this embodiment, the transmission loss of components constituting high-frequency communication equipment can be reduced. [Examples]

[0052] The features of the present invention will be further described below with reference to examples and comparative examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the following specific examples.

[0053] (1) Melting point (Tm) In accordance with JIS K7121:2012, the crystal melting temperature (Tm) of the raw material pellets was determined from the peaks of the DSC detected during the reheating process using a differential scanning calorimeter Pyris1 DSC (manufactured by PerkinElmer) in a temperature range of 25 to 280°C and a heating rate of 10°C / min.

[0054] (2) Glass transition temperature (Tg) In accordance with JIS K7121:2012, the glass transition temperature (Tg) of the raw material pellets was determined from the inflection point of the DSC detected during the reheating process using a differential scanning calorimeter Pyris1 DSC (manufactured by PerkinElmer) in a temperature range of 25 to 280°C at a heating rate of 10°C / min.

[0055] (3) Measurement of UV absorption spectrum of UV absorbers The UV absorber was dissolved in toluene to a concentration of 10 mg / kg, and the UV absorption spectrum was measured using a spectrophotometer (Hitachi High-Tech Science Co., Ltd., UV-Vis-Near-Infrared Spectrophotometer, Model: U-4100) with a 1 cm wide cell. The absorbance at 355 m was then calculated.

[0056] (4) Measurement of UV absorption spectrum of film The UV spectrum of the obtained 10 μm thick film (sample) was measured using a spectrophotometer (Hitachi High-Tech Science Corporation, UV-Vis-Near-Infrared Spectrophotometer, Model: U-4100), and the absorbance at 355 nm was calculated. Absorbance values ​​of 2 or higher were indicated as >2 as the upper limit of measurement.

[0057] (5) Relative permittivity The dielectric constant of the obtained 100 μm thick film (sample) was measured using the cavity resonator method in accordance with JIS C2565:1992, under conditions of a temperature of 23°C, relative humidity of 50%, and frequency of 10 GHz.

[0058] (6) Dielectric loss tangent The dielectric loss tangent of the obtained 100 μm thick film (sample) was measured using the cavity resonator method in accordance with JIS C2565:1992, under conditions of 23°C, 50% relative humidity, and 10 GHz frequency. The dielectric loss tangent was evaluated according to the following evaluation criteria. A: Dielectric loss tangent is 0.001 or less C: Dielectric loss tangent greater than 0.001

[0059] (7) UV laser processability The obtained 100 μm thick film (sample) was set in a UV laser processing machine, and holes with a diameter of Φ0.3 μm were drilled and grooves were cut using a wavelength of 355 nm (focused beam diameter Φ25 μm), an output of 1 W, and 10 irradiations. Note that the Φ0.3 μm hole drilling process requires a shorter irradiation interval than groove cutting, so the resin tends to heat up more easily (if the processability is poor, it is more likely to re-fuse due to the heat). For this reason, the Φ0.3 μm hole drilling process represents an evaluation under more stringent conditions. After each process, the cutability (UV laser processability) was evaluated according to the following criteria. A: Good cutability. It has been cut, and the unnecessary parts have been separated. C: Poor cutability. The material has been cut, but it has been re-welded, and the unnecessary portion has not been completely separated.

[0060] (8) Bleedout evaluation The obtained 100 μm thick film (sample) was cut into 10 cm x 10 cm sections, and each section was evaluated under the following conditions. (a) The film was left standing at room temperature for 30 days. The appearance of the film after standing was observed and evaluated according to the following criteria. A: No bleed-out of the UV absorber was observed. C: The UV absorber had bled out of the film. (b) The film was placed in a constant temperature and humidity chamber set to a relative humidity of 85%. The appearance of the film after standing was observed and evaluated according to the following criteria. A: After 7 days, no bleeding out of the UV absorber was observed. B: No bleed-out of the UV absorber was observed after 3 days, but after 7 days, the UV absorber had bled out of the film. C: After 3 days, the UV absorber had bled out of the film.

[0061] [Non-polar resin] (A)-1: PP (Product name: Novatec PP FY6H, manufactured by Nippon Polypropylene Co., Ltd., melting point 167℃, MFR 1.9g / 10min (230℃ × 2.16kg)) (A)-2: COP (Product name: ZEONEX 790R, manufactured by Nippon Zeon, Tg 163℃, MFR 6g / 10min (280℃ × 2.16kg)) (A)-3:PMP (Product name: TPX DX845, manufactured by Mitsui Chemicals, melting point 232℃, MFR9g / 10min (260℃×5kg)) (A)-4: SPS (Product name: Zarec S107, manufactured by Idemitsu Kosan Co., Ltd., Tg 102℃, melting point 270℃, MFR 18g / 10min (300℃ × 2.16kg)) (A)-5: Maleic anhydride-modified PP (Product name: Modic P555, manufactured by Mitsubishi Chemical Corporation, melting point 168℃, MFR 6.0g / 10min (230℃ × 2.16kg), acid value 8mgKOH / g) (A)-6: SEBS (Product name: ToughTec H1051, manufactured by Asahi Kasei, MFR 0.8g / 10min (230℃ × 2.16kg))

[0062] [UV absorber] (B)-1: Bemotoridinol (triazine-based UV absorber; CAS RN187393-00-6, product name: TinosorbS, manufactured by BASF, absorbance 0.62 (355nm, 10mg / kg)) [ka]

[0063] (B)-2: 2,4,6-Tris(4-butoxy-2-hydroxyphenyl)-1,3,5-triazine (triazine-based UV absorber; CASRN 3135-19-1, manufactured by Tokyo Chemical Industry Co., Ltd., absorbance 0.73 (355 nm, 10 mg / kg)) [ka]

[0064] (B)-3:6-(2,4-bis(butyloxyphenyl))-1,3,5-triazine (triazine-based UV absorber; CAS RN 208343-47-9, product name: Tinubin460, manufactured by BASF, absorbance 0.77 (355nm, 10mg / kg)) [ka]

[0065] (B)-4: Ethylhexyltriazone (triazine-based UV absorber; CAS RN 88122-99-0, manufactured by Tokyo Chemical Industry Co., Ltd., absorbance 0.01 (355 nm, 10 mg / kg)) [ka]

[0066] (B)-5: Avobenzone (benzophenone-based UV absorber; CAS RN 70356-09-1, manufactured by Tokyo Chemical Industry Co., Ltd., absorbance 0.81 (355 nm, 10 mg / kg)) [ka]

[0067] (B)-6:2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (benzotriazole-based UV absorber; CAS RN 70321-86-7, product name ADEKA Stab LA-24, manufactured by ADEKA, absorbance 0.29 (355nm, 10mg / kg)) [ka]

[0068] (B)-7: Bumetrizole (benzotriazole-based UV absorber; CAS RN 3896-11-5, product name Tinubin326, manufactured by BASF, absorbance 0.44 (355nm, 10mg / kg)) [ka]

[0069] (Example 1) (A)-1 was mixed with 4 parts by mass of (B)-1 in 100 parts by mass, dry-blended, and kneaded at 230°C using a Φ25 mm twin-screw extruder equipped with a T-die. The mixture was then extruded through the T-die and cooled on a casting roll at approximately 70°C to produce films (samples) with thicknesses of 10 and 100 μm, and various evaluations were performed.

[0070] (Example 2) Except for using (B)-2 instead of (B)-1, a film (sample) was prepared and various evaluations were performed in the same manner as in Example 1.

[0071] (Example 3) Except for using (B)-3 instead of (B)-1, a film (sample) was prepared and various evaluations were performed in the same manner as in Example 1.

[0072] (Example 4) Except for changing the amount of (B)-1 added to 8 parts by mass, a film (sample) was prepared in the same manner as in Example 1, and various evaluations were performed.

[0073] (Example 5) (A)-2 was mixed with 4 parts by mass of (B)-2 in 100 parts by mass of (A)-2, dry-blended, and kneaded at 280°C using a Φ25 mm twin-screw extruder equipped with a T-die. The mixture was then extruded through the T-die and cooled on a casting roll at approximately 150°C to produce films (samples) with thicknesses of 10 and 100 μm, and various evaluations were performed.

[0074] (Example 6) (A)-3 was mixed with 4 parts by mass of (B)-2 in 100 parts by mass, dry-blended, and kneaded at 260°C using a Φ25 mm twin-screw extruder equipped with a T-die. The mixture was then extruded through the T-die and cooled on a casting roll at approximately 100°C to produce films (samples) with thicknesses of 10 and 100 μm, and various evaluations were performed.

[0075] (Example 7) (A)-4 was mixed with 4 parts by mass of (B)-2 to 100 parts by mass of (A)-4, dry-blended, and kneaded at 300°C using a Φ25 mm twin-screw extruder equipped with a T-die. The mixture was then extruded from the T-die and cooled on a casting roll at approximately 100°C to produce films (samples) with thicknesses of 10 and 100 μm, and various evaluations were performed.

[0076] (Example 8) Except for using (A)-5 instead of (A)-1, a film (sample) was prepared and various evaluations were performed in the same manner as in Example 1.

[0077] (Example 9) (A)-6 was mixed with 4 parts by mass of (B)-2 in 100 parts by mass of (A)-6 and dissolved in toluene solution to a concentration of 25% by mass. The resulting solution was coated onto a release-treated polyethylene terephthalate film (T100H50, 50 μm thick, manufactured by Mitsubishi Chemical) using a bar coater to thicknesses of 40 and 400 μm, and dried in an oven at 80°C for 20 minutes to produce films (samples) with thicknesses of 10 and 100 μm, which were then evaluated in various ways.

[0078] (Comparative Example 1) Except for using (B)-4 instead of (B)-1, a film (sample) was prepared and various evaluations were performed in the same manner as in Example 1.

[0079] (Comparative Example 2) Except for using (B)-5 instead of (B)-1, a film (sample) was prepared and various evaluations were performed in the same manner as in Example 1.

[0080] (Comparative Example 3) Except for using (B)-6 instead of (B)-1, a film (sample) was prepared and various evaluations were performed in the same manner as in Example 1.

[0081] (Comparative Example 4) Except for changing the amount of (B)-6 added to 8 parts by mass, a film (sample) was prepared in the same manner as in Comparative Example 3, and various evaluations were performed.

[0082] (Comparative Example 5) Except for using (B)-7 instead of (B)-1, a film (sample) was prepared and various evaluations were performed in the same manner as in Example 1.

[0083] (Comparative Example 6) Except for changing the amount of (B)-7 added to 8 parts by mass, a film (sample) was prepared in the same manner as in Comparative Example 5, and various evaluations were performed.

[0084] [Table 1]

[0085] As shown in Table 1 above, the examples yielded films with low relative permittivity and dielectric loss tangent, excellent laser processability, and low bleed-out properties. Such films are effective as communication materials utilizing high frequencies. On the other hand, the comparative examples failed to achieve both laser processability and low bleed-out properties.

Claims

1. A film for communication substrates comprising a non-polar resin and a triazine-based ultraviolet absorber, wherein the absorbance at a wavelength of 355 nm per 10 μm thickness is 1.0 or higher.

2. The film for a communication substrate according to claim 1, wherein the content of the triazine-based ultraviolet absorber per 100 parts by mass of the nonpolar resin is 1 to 10 parts by mass.

3. The film for a communication substrate according to claim 1, wherein the absorbance of the triazine-based ultraviolet absorber at a wavelength of 355 nm is 0.5 or more.

4. The film for a communication substrate according to claim 1, wherein the triazine-based ultraviolet absorber is a compound represented by the following formula (1). 【Chemistry 1】 (In formula (1), R １ ~R ３ Each of these independently represents an alkyl group having 1 to 12 carbon atoms, R ４ ~R ６ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a hydroxyl group.

5. The film for a communication substrate according to claim 1, wherein the nonpolar resin is at least one selected from the group consisting of propylene resin, ethylene resin, cyclic olefin resin, styrene resin, and polymethylpentene.

6. A film for a communication substrate according to claim 1, wherein the relative permittivity at a frequency of 10 GHz, a temperature of 23°C, and a relative humidity of 50% is 3.0 or less.

7. The film for a communication substrate according to claim 1, wherein the dielectric loss tangent at a frequency of 10 GHz, a temperature of 23°C, and a relative humidity of 50% is 0.0010 or less.

8. A communication device comprising a film for a communication substrate according to any one of claims 1 to 7.

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