JP7202744B1 - Manufacturing method of high frequency dielectric for RF tag - Google Patents

Abstract

An object of the present invention is to provide a high-frequency dielectric that has both good high-frequency characteristics and mechanical characteristics and is advantageous in terms of cost. An RF tag in which an antenna and an IC chip are sandwiched between high-frequency dielectrics, wherein the high-frequency dielectric contains polyolefin resin and heavy calcium carbonate powder at a mass ratio of 50:50 to 10:90. and a dielectric constant ε of 5 or less and a dielectric loss tangent tan δ of 5×10 −4 or less at a frequency of 1 GHz or higher and at a temperature of 25° C. In particular, an RF tag for contactless communication using a frequency in the 2.45 GHz band conforming to ISO/IEC 18000-4. [Selection drawing] Fig. 1

Description

The present invention relates to RF tags. More specifically, the present invention relates to an RF tag that sandwiches an antenna and an IC chip with a high-frequency dielectric material in which heavy calcium carbonate is highly filled in a polyolefin resin, and that has both good high-frequency characteristics and mechanical characteristics.

2. Description of the Related Art With the recent development of an information-oriented society, it is becoming common to attach tags in which information is recorded to clothes, products, etc., and to manage products and analyze the flow of people through these tags. Among them, RF tags equipped with IC chips capable of writing and reading information to and from the tags in a non-contact state are rapidly becoming popular due to their excellent convenience.

An RF tag is generally composed of an antenna, an IC chip connected to it, and a base sheet for holding them, and is optionally provided with an adhesive layer or surface sheet. As the base sheet, a thermoplastic resin such as PET resin or polyamide, or paper is usually used (Patent Documents 1 to 3).

JP 2006-127424 A JP 2019-191987 A JP 2015-156083 A

In recent years, the frequency of semiconductor elements mounted in electronic devices has been increasing, and RF tags that perform contactless communication at a frequency of 2.45 GHz band conforming to ISO/IEC 18000-4 have recently been used. It is becoming possible to However, RF tags having a base sheet of PET resin, polyamide, or the like, as described in Patent Documents 1 to 3, generally have a drawback of poor high-frequency characteristics. Further, RF tags using paper as a base sheet have problems in terms of mechanical properties such as strength and elongation. In particular, in the case of RF tags that use frequencies in the 2.45 GHz band, poor high-frequency characteristics pose problems in practical use, such as restricted reading distances and erroneous reading results. RF tags that use frequencies in the 2.45 GHz band are also susceptible to the adverse effects of moisture in the environment in which they are used. communication error may occur.

The present invention has been made in view of the above circumstances, and has excellent high-frequency characteristics, for example, it is possible to perform good non-contact communication even at a frequency in the 2.45 GHz band, and it also has good mechanical characteristics. An object of the present invention is to provide an RF tag that is also advantageous in terms of the aspect.

As a result of extensive studies, the present inventors have found that in an RF tag in which an antenna and an IC chip are sandwiched between base sheets, by using a high-frequency dielectric material having specific materials and characteristics as the base sheet, good mechanical properties can be obtained. is developed, the high-frequency characteristics of the RF tag are improved, and good non-contact communication becomes possible even at frequencies in the 2.45 GHz band, for example.

That is, the present invention for solving the above problems is an RF tag in which an antenna and an IC chip are sandwiched between high-frequency dielectrics,
The high-frequency dielectric contains polyolefin resin and heavy calcium carbonate powder at a mass ratio of 50:50 to 10:90, and has a dielectric constant ε of 5 or less at a frequency of 1 GHz or higher and a temperature of 25 ° C. , and a dielectric loss tangent tan δ of 5×10 ⁻⁴ or less.

An embodiment of the RF tag of the present invention provides an RF tag, wherein the polyolefin-based resin is a polypropylene-based resin and/or a polyethylene-based resin.

In one embodiment of the RF tag of the present invention, the RF tag is presented, wherein the ground calcium carbonate powder is surface-treated ground calcium carbonate powder.

In one embodiment of the RF tag of the present invention, the heavy calcium carbonate powder has an average particle size of 0.7 μm or more and 7.0 μm or less by an air permeation method according to JIS M-8511. be

In one embodiment of the RF tag of the present invention, the heavy calcium carbonate powder has a BET specific surface area of 0.1 m ² /g or more and 10.0 m ² /g or less, and a circularity of 0.50 or more and 0.95. RF tags are shown, which are:

In one embodiment of the RF tag of the present invention, the heavy calcium carbonate powder contains at least two groups of particles having different average particle sizes, and as the at least two groups of particles having different average particle sizes, A primary calcium carbonate particle group having an average particle size of 0.7 μm or more and less than 2.2 μm by an air permeation method according to JIS M-8511, and an average particle size of 2.2 μm by an air permeation method according to JIS M-8511. An RF tag containing second calcium carbonate particles with a mass ratio of 1:1 to 5:1.

In one embodiment of the RF tag of the present invention, when the average particle size of the first calcium carbonate particle group is a and the average particle size of the second calcium carbonate particle group is b, the a/b ratio is An RF tag is shown that is 0.85 or less.

In one embodiment of the RF tag of the present invention, an RF tag is presented in which the porosity of the high-frequency dielectric is 5% or more and 35% or less.

In one embodiment of the RF tag of the present invention, in at least one of the high-frequency dielectrics sandwiching the antenna and the IC chip, an adhesive layer is provided on the side contacting the antenna and the IC chip. shown.

In one embodiment of the RF tag of the present invention, an RF tag is shown, which is an RF tag for contactless communication using a frequency of 2.45 GHz band conforming to ISO/IEC 18000-4.

According to the present invention, it is possible to provide an RF tag that has excellent high-frequency characteristics, can perform good non-contact communication even at a frequency of, for example, 2.45 GHz band, and has good mechanical characteristics. The RF tag of the present invention is also advantageous in terms of cost because the main raw materials of the base sheet are polyolefin resin and heavy calcium carbonate.

1 is a top perspective view showing one embodiment of an RF tag of the present invention; FIG. FIG. 4 is a schematic cross-sectional view showing another embodiment of the RF tag of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail based on embodiments, but the present invention is not limited to these embodiments.

[RF tag]
The RF tag of the present invention is an RF tag in which an antenna and an IC chip are sandwiched between high-frequency dielectrics, and the high-frequency dielectric is composed of polyolefin resin and heavy calcium carbonate powder at a mass ratio of 50:50 to 10:90. and has a dielectric constant ε of 5 or less and a dielectric loss tangent tan δ of 5×10 ⁻⁴ or less at a frequency of 1 GHz or higher and at a temperature of 25° C. The members constituting the RF tag of the present invention are described below.

FIG. 1 is a top perspective view showing one embodiment of the RF tag of the present invention. In the RF tag 1, an IC chip 11 on which data is recorded or for recording data, and an antenna 12 for contactless communication for exchanging information between the IC chip 11 and an external reader/writer, It is sandwiched by high frequency dielectrics 13 and 14 . Here, the shape and appearance of the RF tag 1 are not particularly limited, and in addition to the card type shown in FIG.

In the RF tag of the present invention, there are no particular restrictions on the type of IC chip, and various commonly used ones can be used depending on the purpose. For example, as in the embodiment shown in FIG. 1, a chip in which the control circuit and the memory are integrated may be used, and the IC chip for control and the IC chip for data storage may each be an RF chip. It may be provided in the tag. The type of antenna is not particularly limited, and various common types of antennas such as dipole antennas, planar antennas (patch antennas), loop antennas, capacitive coupling antennas, and Yagi antennas are used depending on the communication frequency used. can do. In particular, a dipole antenna or a planar antenna is preferable when using a frequency in the 2.45 GHz band. The material thereof is not particularly limited, and desired metal materials such as copper, aluminum, nickel, silver and various solders can be used.

FIG. 2 is a schematic cross-sectional view showing still another embodiment of the RF tag of the present invention. In this embodiment, an adhesive layer 15 is provided on one side of the high-frequency dielectric 13 that contacts the antenna 12 and the IC chip 11 . An adhesive layer 16 and a release material layer 17 are attached to the surface of the other high-frequency dielectric 14 that is not in contact with the IC chip 11 and the antenna 12 . In this embodiment, since the IC chip 11 and the antenna 12 are bonded to the high-frequency dielectric 13 via the adhesive layer 15, positional deviation within the RF tag 1 and accompanying erroneous transmission of data can be prevented. There is no fear of coming. In addition, since the RF tag 1 has the adhesive layer 16 on one side, it can be easily attached to products, clothes, and the like. Moreover, since the IC chip 11 and the antenna 12 are not bonded to the high-frequency dielectric 14 on the side having the adhesive layer 16, there is an advantage that they are less likely to be adversely affected by deformation, expansion, contraction, movement, etc. of the adherend. However, the present invention is not limited to such embodiments. The effects of the present invention are mainly brought about by the high frequency dielectrics 13 and 14. FIG.

≪High frequency dielectric≫
The RF tag of the present invention is characterized in that the high-frequency dielectric contains polyolefin resin and heavy calcium carbonate powder at a mass ratio of 50:50 to 10:90, and has a frequency of 1 GHz or higher and a temperature of 25 ° C. and a dielectric constant ε of 5 or less and a dielectric loss tangent tan δ of 5×10 ⁻⁴ or less. Conventional RF tags that use paper or PET resin as the base sheet, and RF tags that use polyolefin resin that does not contain heavy calcium carbonate powder as the base sheet, suffer from erroneous data transmission at high frequencies such as the 2.45 GHz band. There is a fear of coming. On the other hand, the RF tag of the present invention using the above-mentioned high-frequency dielectric as a base sheet has excellent high-frequency characteristics, and can perform good non-contact communication even at frequencies in the 2.45 GHz band, for example. The polyolefin resin and heavy calcium carbonate powder contained in the high-frequency dielectric (base sheet) are described below.

<Polyolefin resin>
In the RF tag according to the present invention, the polyolefin resin that can be used as the high-frequency dielectric is not particularly limited, and various resins can be used according to the application, function, etc. of the RF tag. Polyolefin resin is a resin mainly composed of olefin component units, specifically polypropylene resin, polyethylene resin, polymethyl-1-pentene, cyclic olefin polymer, ethylene-cyclic olefin copolymer, etc. polyolefin resin; ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid copolymer metal salt (ionomer), ethylene-acrylic acid alkyl ester copolymer Polymers, ethylene-methacrylic acid alkyl ester copolymers, functional group-containing polyolefin resins such as maleic acid-modified polyethylene and maleic acid-modified polypropylene, and mixtures of two or more thereof.

Here, the phrase “mainly composed of” olefin component units means that the olefin component units are contained in the polyolefin resin in an amount of 50% by mass or more, and the content is preferably 75% by mass or more. It is preferably 85% by mass or more, more preferably 90% by mass or more. In particular, resins in which substantially all of the monomer components are olefins, especially polyolefin homopolymers (homopolymers) are preferred. Such polyolefin resins have a dielectric constant of generally 3 or less, particularly 2.5 or less, for example, in the range of 2.0 to 2.3. It is suitable for high-frequency dielectrics having a tangent tan δ of 5×10 ⁻⁴ or less. Since polyolefin-based resins, especially homopolymers, have low hydrophilicity, it is possible to reduce RF tag communication errors caused by moisture in the usage environment. The method for producing the polyolefin resin used in the present invention is not particularly limited, and can be obtained by any method using a radical initiator such as a Ziegler-Natta catalyst, a metallocene catalyst, oxygen, or a peroxide. It may be something else.

Examples of the polypropylene-based resin include resins having a propylene component unit of 50% by mass or more, and examples thereof include propylene homopolymers and copolymers of propylene and other copolymerizable monomers. Propylene homopolymers include isotactic, syndiotactic, atactic, hemiisotactic, and linear or branched polypropylenes exhibiting various stereoregularities. The above copolymer may be a random copolymer or a block copolymer, and may be a terpolymer as well as a binary copolymer. Copolymerization components (other monomers) include, but are not limited to, tetrafluoroethylene, vinyl acetate, and the like. In the present invention, it is preferable to use a homopolymer or a resin copolymerized with a small amount of another monomer, for example, less than 5% by weight. It should be noted that even in propylene homopolymers, as a result of polymerization, there are cases where a structure as if an α-olefin such as hexene is copolymerized is partly included, but in the present invention, such a polymer is also included. , is broadly included as a propylene homopolymer (propylene homopolymer). Moreover, these polypropylene resins can be used individually or in mixture of 2 or more types.

Examples of the polyethylene-based resin include resins having an ethylene component unit of 50% by mass or more. Examples include high-density polyethylene (HDPE), low-density polyethylene (LDPE), medium-density polyethylene, and linear low-density polyethylene (LLDPE). , ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, ethylene-propylene-butene 1 copolymer, ethylene-butene 1 copolymer, ethylene-hexene 1 copolymer, ethylene-4-methylpentene 1 copolymer Coalescing, ethylene-octene 1 copolymer, etc., and mixtures of two or more thereof.

Among the polyolefin resins described above, polypropylene resins and/or polyethylene resins, particularly polypropylene resins, are preferably used because of their particularly excellent balance between mechanical properties and heat resistance. Among them, propylene homopolymer is preferred. As described above, the propylene homopolymer may be linear or branched polypropylene having various steric structures, and its molecular weight is not particularly limited. Propylene homopolymer, particularly isotactic polypropylene, is a thermoplastic resin having a low dielectric constant and dielectric loss tangent among various polymer materials, and is suitable for the high-frequency dielectric constituting the present invention. A plurality of propylene homopolymers having different steric structures and molecular weights can be used together.

The high-frequency dielectric material constituting the present invention may further contain other resin components in addition to the polyolefin-based resin as described above. Thermoplastic resins such as poly (meth) acrylic acid (ester), polyvinyl acetate, polyacrylonitrile, polystyrene, ABS resin, polycarbonate, polyamide, polyvinyl alcohol, petroleum hydrocarbon resin, coumarone-indene resin; Elastomers such as butadiene copolymers, styrene-isoprene copolymers, styrene-butadiene-ethylene copolymers, styrene-isoprene-ethylene copolymers, acrylonitrile-butadiene copolymers, fluorine-based elastomers, etc., may be mentioned. Not limited. By blending these resin components, each component can be more uniformly dispersed in the resin composition constituting the high-frequency dielectric, and physical properties and workability can be improved. However, considering the compatibility of various resin components, etc., the thermoplastic resin in the high-frequency dielectric constituting the present invention is preferably 90% by mass or more, more preferably 97% by mass or more, and particularly preferably substantially the entire amount of It consists of the above polyolefin resin. If the high-frequency dielectric does not substantially contain resin components other than polyolefin resin, it is particularly easy to select raw materials, compositions, and processing conditions.

<Heavy calcium carbonate powder>
The high frequency dielectric in the RF tag according to the present invention contains a large amount of heavy calcium carbonate powder. Here, heavy calcium carbonate is obtained by mechanically pulverizing and processing natural limestone or the like, and is clearly distinguished from synthetic calcium carbonate produced by chemical precipitation reaction or the like. The pulverization method includes a dry method and a wet method, and the dry method is preferred.

The heavy calcium carbonate powder, for example, differs from the synthetic light calcium carbonate in that it is characterized by surface irregularities and a large specific surface area due to the fact that the particles are formed by pulverization. Since the heavy calcium carbonate powder has such an irregular shape and a large specific surface area, when blended in a polyolefin resin, the heavy calcium carbonate powder forms a larger contact interface with the polyolefin resin. It has an effect on uniform dispersion.

In order to enhance the dispersibility or reactivity of the heavy calcium carbonate powder, the surface may be surface-modified by a conventional method. Examples of surface modification methods include physical methods such as plasma treatment, and chemical surface treatment using a coupling agent or surfactant. Examples of coupling agents include silane coupling agents and titanium coupling agents. Surfactants may be anionic, cationic, nonionic or amphoteric, and examples thereof include higher fatty acids, higher fatty acid esters, higher fatty acid amides and higher fatty acid salts. On the contrary, it may contain heavy calcium carbonate powder that is not surface-treated.

Although not particularly limited, the heavy calcium carbonate powder preferably has a BET specific surface area of 0.1 m ² /g or more and 10.0 m ² /g or less. When the specific surface area is within this range, the workability of the obtained high-frequency dielectric tends to be suppressed.

In addition, the amorphousness of the heavy calcium carbonate powder (particles) can be expressed by a low degree of spheroidization of the particle shape, and is not particularly limited. It is 0.50 or more and 0.95 or less, more preferably 0.55 or more and 0.93 or less, and still more preferably 0.60 or more and 0.90 or less. When the roundness of the heavy calcium carbonate powder is within this range, the strength and moldability of the high-frequency dielectric material are also moderate. Here, the circularity can be expressed by (the projected area of the grain)/(the area of the circle having the same circumferential length as the projected circumferential length of the grain). The method for measuring the roundness is not particularly limited, and for example, the projected area and the projected peripheral length of the grain may be measured from a micrograph, or image analysis software that is generally commercially available may be used.

The heavy calcium carbonate powder is not particularly limited, but preferably has an average particle size of 0.7 μm or more and 7.0 μm or less, more preferably 0.8 μm or more and 6.0 μm or less, and further preferably, It is 1.0 μm or more and 4.0 μm or less. The average particle size of the heavy calcium carbonate powder described in this specification is a value calculated from the results of measuring the specific surface area by an air permeation method according to JIS M-8511. As a measuring device, for example, a specific surface area measuring device SS-100 manufactured by Shimadzu Corporation can be preferably used. If the average particle size is larger than 7.0 μm, for example, when a sheet-like high-frequency dielectric is formed, the heavy calcium carbonate powder protrudes from the surface, depending on the layer thickness of the high-frequency dielectric, and the powder may fall off, or the surface properties, mechanical strength, etc. may be impaired. In particular, the particle size distribution preferably does not contain powder (particles) having a particle size of 45 μm or more. On the other hand, if the particles are too fine, the viscosity will increase significantly when kneaded with the above-mentioned resin, which may make it difficult to manufacture the high-frequency dielectric. Such a problem can be prevented by setting the average particle size of the inorganic powder to 0.7 μm or more and 7.0 μm or less, particularly 0.8 μm or more and 6.0 μm or less.

In the present invention, the heavy calcium carbonate powder contains at least two groups of particles having different average particle sizes, and the at least two groups of particles having different average particle sizes are air according to JIS M-8511. A first calcium carbonate particle group having an average particle size of 0.7 μm or more and less than 2.2 μm by a permeation method, and a second calcium carbonate particle group having an average particle size of 2.2 μm or more and 7.0 μm or less by an air permeation method according to JIS M-8511. and calcium carbonate particles at a mass ratio of 1:1 to 5:1. As a result, it is possible to improve the surface properties of the high-frequency dielectric material, as well as physical properties such as printability and blocking properties. In addition, uneven distribution of calcium carbonate is suppressed, a high-frequency dielectric with good appearance and mechanical properties such as elongation at break can be obtained, and falling off of calcium carbonate from the high-frequency dielectric can be reduced.

Although not particularly limited, when the average particle size of the first calcium carbonate particle group is a and the average particle size of the second calcium carbonate particle group is b, the a/b ratio is 0.85 or less, It is desirable to be able to classify roughly so that it is more preferably about 0.10 to 0.70, and still more preferably about 0.10 to 0.50. This is because a particularly excellent effect can be expected by jointly using particles having such a clear difference in average particle size to some extent. Further, each of the first calcium carbonate particle group and the second calcium carbonate particle group preferably has a coefficient of variation (Cv) of the distribution of the particle size (μm) of about 0.01 to 0.10, particularly 0 It is desirable to be about 0.03 to 0.08. If the variation in particle size defined by the coefficient of variation (Cv) is this level, it is considered that each powder group can provide more complementary effects. Three or more calcium carbonate groups having different average particle size distributions may be used. Moreover, it is preferable that each of the powders of the first calcium carbonate particle group and the second calcium carbonate particle group is surface-treated ground calcium carbonate.

In the RF tag of the present invention, the high-frequency dielectric contains the heavy calcium carbonate powder as described above, but may also contain inorganic substance powders other than these. Examples include powdery carbonates, sulfates, silicates, phosphates, borates, oxides, or hydrates thereof of calcium, magnesium, aluminum, titanium, iron, zinc, etc. Specifically, for example, light calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, calcium silicate, Aluminum sulfate, magnesium sulfate, calcium sulfate, magnesium phosphate, barium sulfate, silica sand, carbon black, zeolite, molybdenum, diatomaceous earth, sericite, shirasu, calcium sulfite, sodium sulfate, potassium titanate, bentonite, wollastonite, dolomite, Graphite etc. are mentioned. These may be synthetic or derived from natural minerals, and may be contained singly or in combination of two or more.

Considering the physical properties of the RF tag to be obtained and the formability of the high-frequency dielectric, the inorganic substance powder in the high-frequency dielectric is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably contains unavoidable impurities. consists essentially entirely of the above ground calcium carbonate powder. In addition, when the insulator constituting the present invention contains an inorganic substance powder other than the heavy calcium carbonate powder, it preferably contains an inorganic substance powder having a dielectric constant of 5 or less, further 4 or less, particularly 3 or less. . Calcium carbonate has a dielectric constant of about 1.6, which is a considerably low dielectric constant among inorganic substances. If the high-frequency dielectric does not substantially contain inorganic substance powders other than heavy calcium carbonate powder, physical properties such as high-frequency characteristics and mechanical characteristics will be particularly good.

<Resin composition>
The high-frequency dielectric constituting the RF tag of the present invention is made of a resin composition containing a polyolefin resin and an inorganic substance powder such as heavy calcium carbonate powder. In the resin composition, the polyolefin resin and heavy calcium carbonate powder are contained in a mass ratio of 50:50 to 10:90. If the content of the heavy calcium carbonate powder is too small, it will be difficult to obtain physical properties such as texture and strength of the high-frequency dielectric.

Moreover, the ratio of the inorganic substance powder, particularly the ratio of the heavy calcium carbonate powder, to the total mass of the resin composition is preferably 52% by mass or more, more preferably 55% by mass or more. The upper limit of the ratio is preferably 80% by mass or less, more preferably 75% by mass or less, and particularly preferably 70% by mass or less.

If necessary, other additives may be added as auxiliary agents to the resin composition constituting the high-frequency dielectric. Other additives include, for example, colorants, lubricants, coupling agents, fluidity modifiers (fluidity modifiers), cross-linking agents, dispersants, antioxidants, ultraviolet absorbers, flame retardants, stabilizers, and electrifying agents. Inhibitors, foaming agents, plasticizers, etc. may be blended. These additives may be used alone or in combination of two or more. Moreover, these may be blended in the kneading step described later, or may be blended in the raw material components in advance before the kneading step.

In the resin composition constituting the high-frequency dielectric, the amount of these other additives added is not particularly limited as long as it does not impede the desired physical properties and processability. , each of these other additives is about 0 to 10% by mass, particularly about 0.04 to 5% by mass, and the total amount of the other additives is 10% by mass or less. It is hoped that For example, 10 to 45% by mass, particularly 20 to 25% by mass of polyolefin resin; 90 to 45% by mass, particularly 75 to 55% by mass of heavy calcium carbonate powder; and 0 to 10% by weight, especially 0.04 to 5% by weight of the above additives may be contained.

Among these additives, those considered to be important will be described below by way of examples, but the additives are not limited to these.

Examples of plasticizers include triethyl citrate, acetyl-triethyl citrate, dibutyl phthalate, diaryl phthalate, dimethyl phthalate, diethyl phthalate, di-2-methoxyethyl phthalate, dibutyl tartrate, and o-benzoylbenzoic acid. Ester, diacetin, epoxidized soybean oil and the like. These plasticizers are usually blended in about several mass % with respect to the thermoplastic resin, but the amount is not limited to these ranges, and depending on the application of the high frequency dielectric, epoxidized soybean oil etc. Blending is also possible. However, in the high-frequency dielectric constituting the present invention, the blending amount is preferably about 0.5 to 10 parts by weight, particularly about 1 to 5 parts by weight, per 100 parts by weight of the thermoplastic resin.

As the colorant, any of known organic pigments, inorganic pigments, or dyes can be used. Specifically, organic pigments such as azo-based, anthraquinone-based, phthalocyanine-based, quinacridone-based, isoindolinone-based, diosazine-based, perinone-based, quinophthalone-based, and perylene-based pigments, ultramarine blue, titanium oxide, titanium yellow, and iron oxide. (Rouge), chromium oxide, zinc white, carbon black and other inorganic pigments.

Examples of lubricants include fatty acid-based lubricants such as stearic acid, hydroxystearic acid, complex stearic acid, and oleic acid; fatty alcohol-based lubricants; stearamide, oxystearamide, oleylamide, erucylamide, ricinolamide, behenamide, and methylol. Aliphatic amide-based lubricants such as amides, methylenebisstearamide, methylenebisstearobehenamide, higher fatty acid bisamic acids, complex amides; n-butyl stearate, methyl hydroxystearate, polyhydric alcohol fatty acid esters, Fatty acid ester-based lubricants such as saturated fatty acid esters and ester-based waxes; and fatty acid metal soap-based lubricants such as zinc stearate and magnesium stearate.

Phosphorus-based antioxidants, phenol-based antioxidants, and pentaerythritol-based antioxidants can be used as antioxidants. Phosphorus-based, more specifically phosphorus-based antioxidant stabilizers such as phosphites and phosphates are preferably used. Examples of phosphites include triphenyl phosphite, trisnonylphenyl phosphite, tris(2,4-di-t-butylphenyl) phosphite, and other phosphorous acid triesters, diesters, and monoesters. is mentioned.

Phosphate esters include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris(nonylphenyl) phosphate, 2-ethylphenyl diphenyl phosphate and the like. These phosphorus-based antioxidants may be used alone, or two or more of them may be used in combination.

Phenolic antioxidants include α-tocopherol, butylhydroxytoluene, sinapyl alcohol, vitamin E, n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2- t-butyl-6-(3'-t-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl acrylate, 2,6-di-t-butyl-4-(N,N-dimethyl aminomethyl)phenol, 3,5-di-t-butyl-4-hydroxybenzylphosphonate diethyl ester, and tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxymethyl]methane etc., and these can be used alone or in combination of two or more.

Although the flame retardant is not particularly limited, for example, halogen-based flame retardants or non-phosphorus-based halogen-based flame retardants such as phosphorus flame retardants and metal hydrates can be used. Specific examples of halogen flame retardants include halogenated bisphenol compounds such as halogenated bisphenylalkanes, halogenated bisphenyl ethers, halogenated bisphenylthioethers, and halogenated bisphenylsulfones, brominated bisphenol A, bromine Bisphenol-bis(alkyl ether) compounds such as bisphenol S, chlorinated bisphenol A, and chlorinated bisphenol S, and phosphorus-based flame retardants such as aluminum tris(diethylphosphinate) and bisphenol A bis(diphenyl phosphate). , triaryl isopropyl phosphate, cresyl di-2,6-xylenyl phosphate, aromatic condensed phosphate esters, etc., and metal hydrates such as aluminum trihydrate, magnesium hydroxide, combinations thereof, etc. can be exemplified, respectively, and these can be used alone or in combination of two or more. It works as a flame retardant assistant, and can improve the flame retardant effect more effectively. Furthermore, for example, antimony oxides such as antimony trioxide and antimony pentoxide, zinc oxide, iron oxide, aluminum oxide, molybdenum oxide, titanium oxide, calcium oxide, magnesium oxide, etc. can be used in combination as flame retardant aids. .

The foaming agent is mixed or injected into the thermoplastic resin composition in a molten state in a melt-kneader, and undergoes a phase change from solid to gas, liquid to gas, or gas itself. Used to control the porosity (expansion ratio) of high frequency dielectrics. A foaming agent that is liquid at room temperature undergoes a phase change to a gas depending on the resin temperature and dissolves in the molten resin, while a foaming agent that is gas at room temperature does not undergo a phase change and dissolves in the molten resin as it is. The foaming agent dispersed and dissolved in the molten resin expands inside the sheet as the pressure is released when the molten resin is extruded into a sheet from an extrusion die, forming a large number of fine closed cells within the sheet and foaming. A sheet is obtained. The foaming agent secondarily acts as a plasticizer that lowers the melt viscosity of the raw material resin composition, and lowers the temperature for making the raw resin composition plasticized.

Examples of blowing agents include aliphatic hydrocarbons such as propane, butane, pentane, hexane and heptane; alicyclic hydrocarbons such as cyclobutane, cyclopentane and cyclohexane; chlorodifluoromethane, difluoromethane, trifluoromethane, trichlorofluoromethane; Methane, dichloromethane, dichlorofluoromethane, dichlorodifluoromethane, chloromethane, chloroethane, dichlorotrifluoroethane, dichloropentafluoroethane, tetrafluoroethane, difluoroethane, pentafluoroethane, trifluoroethane, dichlorotetrafluoroethane, trichlorotrifluoroethane , tetrachlorodifluoroethane and perfluorocyclobutane; inorganic gases such as carbon dioxide, nitrogen and air; and water.

As the foaming agent, for example, a carrier resin containing an active ingredient of the foaming agent can be preferably used. Examples of carrier resins include crystalline olefin resins. Among these, crystalline polypropylene resins are preferred. Moreover, hydrogen carbonate etc. are mentioned as an active ingredient. Among these, hydrogen carbonate is preferred. A blowing agent concentrate containing a crystalline polypropylene resin as a carrier resin and a hydrogen carbonate as a thermally decomposable blowing agent is preferred.

The content of the foaming agent contained in the foaming agent in the molding process can be appropriately set according to the amount of the polyolefin resin and heavy calcium carbonate powder, etc., and is 0.04 to 0.04 with respect to the total mass of the resin composition. A range of 5.00% by mass is preferred.

Various commonly used fluidity modifiers can also be used. Examples include, but are not limited to, peroxides such as dialkyl peroxides such as 1,4-bis[(t-butylperoxy)isopropyl]benzene and the like. Depending on the type of polyolefin resin used, these peroxides also act as cross-linking agents. In particular, when the polyolefin resin has diene-derived structural units, part of the copolymer is crosslinked by the action of the peroxide, which helps control the physical properties and workability of the thermoplastic resin composition. obtain. The amount of the peroxide to be added is not particularly limited, but it is preferably in the range of 0.04 to 2.00% by mass, particularly 0.05 to 0.50% by mass, based on the total mass of the resin composition. .

<Method for preparing resin composition>
As a method for preparing the above resin composition, a conventional method can be used, and the method can be appropriately set according to the molding method (extrusion molding, injection molding, vacuum molding, etc.). For example, it can be prepared by melt-kneading a polyolefin resin and heavy calcium carbonate powder. Melt-kneading is preferably carried out by applying a high shear stress while dispersing each component uniformly. As a mixing device, various devices such as a general extruder, a kneader, and a Banbury mixer can be used. The prepared thermoplastic resin composition can be made, for example, into pellets of a desired shape and size and used in the production of high frequency dielectrics. Depending on the desired shape of the high-frequency dielectric, it is also possible to knead each raw material to prepare a thermoplastic resin composition and at the same time to mold the high-frequency dielectric. For example, a sheet-shaped high-frequency dielectric can be produced by kneading various raw materials with a twin-screw extruder and extruding a sheet-shaped material.

<Manufacturing method of high frequency dielectric>
The method for manufacturing the high-frequency dielectric constituting the RF tag of the present invention is not particularly limited as long as it can be molded into a desired shape, and conventionally known extrusion molding, injection molding, vacuum molding, blow molding, calendar molding, etc. Any method may be used. Furthermore, even in the embodiment in which the high-frequency dielectric is a foamed body, conventionally known liquid phase foaming methods such as injection foaming, extrusion foaming, foam blowing, etc., as long as they can be molded into a desired shape, or, for example, bead foaming, Any solid phase foaming method such as batch foaming, press foaming, normal pressure secondary foaming, etc. can be used. In one embodiment of the resin composition containing the crystalline polypropylene as the carrier resin and the hydrogen carbonate as the thermally decomposable foaming agent, an injection foaming method and an extrusion foaming method can be desirably used. Among these, the extrusion molding method is preferred.

Although the extrusion method is not particularly limited, it is preferable to use a twin-screw extruder, particularly a T-die type twin-screw extruder, in consideration of the smoothness of the substrate sheet surface. Using such a molding machine, for example, the melting point of the polyolefin resin + 55 ° C. or less, preferably the melting point of the polyolefin resin or more and the melting point + 55 ° C. or less, more preferably the melting point of the polyolefin resin + 10 ° C. or more and the melting point of the polyolefin resin By extruding at a temperature of +45° C. or lower, a high frequency dielectric with excellent appearance and physical properties can be produced.

The base sheet (high frequency dielectric) extruded as described above is preferably then subjected to a stretching treatment. The stretching treatment is not particularly limited, and the film can be stretched uniaxially, biaxially, or multiaxially (such as by tubular stretching) during or after molding. More preferably, it is uniaxially or biaxially stretched (for example, longitudinally and/or laterally stretched). Moreover, the draw ratio is preferably 1.1 times or more and 10.0 times or less, particularly 1.5 times or more and 5.0 times or less. In the case of biaxial stretching, sequential biaxial stretching or simultaneous biaxial stretching may be used. Such a stretching treatment can improve the mechanical properties of the high-frequency dielectric and facilitate adjustment of the dielectric constant and dielectric loss tangent to appropriate values. In addition, the resin composition containing the heavy calcium carbonate powder can be stretched to form minute voids, and as a result, it is possible to reduce the weight of the resin composition. The porosity of the high-frequency dielectric can also be adjusted by blending the above foaming agent.

<High frequency characteristics of high frequency dielectric>
The high-frequency dielectric produced as described above generally exhibits excellent high-frequency characteristics, and has a dielectric constant ε of 5 or less and a dielectric loss tangent tan δ of 1×10 ⁻³ or less at a frequency of 1 GHz or higher and at a temperature of 25° C. Become. The high-frequency dielectric constituting the RF tag of the present invention has a dielectric constant ε of 5 or less, preferably 3 or less at a frequency of 1 GHz or higher and a temperature of 25 ° C., and a dielectric loss tangent tan δ of 1 × 10 ^-3 as described above. Below, preferably 7×10 ⁻⁴ or less, more preferably 5×10 ⁻⁴ or less, further preferably 4×10 ⁻⁴ or less, particularly preferably 3×10 ⁻⁴ or less, exhibit excellent high frequency characteristics. Moreover, since polyolefin-based resin and heavy calcium carbonate powder are used as main raw materials, it has good mechanical properties and is advantageous in terms of cost.

There are no particular restrictions on the shape and configuration of the high-frequency dielectric, and the desired shape and configuration can be made according to the intended RF tag. In particular, the high-frequency dielectric has a thickness of 20 μm or more and 1000 μm or less, particularly 50 μm or more and 500 μm or less, and a draw ratio of 1.1 times or more and 10.0 times or less, especially 1.5 times or more and 5.0 times or less uniaxial or biaxial Stretched sheets are preferred. A desired shape can be obtained by cutting or shaving the high-frequency dielectric from such a sheet.

The high-frequency dielectric constituting the RF tag of the present invention also preferably has a porosity of 5% or more and 35% or less, particularly 10% or more, further preferably 15% or more and 30% or less. If the high-frequency dielectric contains fine voids at such a ratio, the dielectric constant and the dielectric loss tangent may decrease. Here, the porosity can be calculated from the density (specific gravity) of the high frequency dielectric. For example, in the case of a sheet made of polypropylene resin and calcium carbonate, the true specific gravity ρ _o of the mixture is calculated from the blending amount using the respective true specific gravities of 0.90 and 2.71. Based on the ratio between that value and the specific gravity ρ of the actual sheet, the porosity can be calculated according to the following formula.
Porosity (volume%) = (1-ρ/ρ _o ) × 100

The porosity and size of the voids in the high-frequency dielectric can be adjusted, for example, by stretching. When a thermoplastic resin composition containing an inorganic substance powder such as a heavy calcium carbonate powder is stretched, the inorganic particles are used as nuclei for stretching, resulting in large voids. It is also possible to adjust the porosity by adding the foaming agent described above. The porosity can also be adjusted by extrusion molding without adding a foaming agent or performing the stretching step. Air entrained in the extruder is usually vented out of the molding machine, but part of it may be caught in the thermoplastic resin composition and form fine voids. Therefore, it is possible to adjust the porosity of the high-frequency dielectric within the above range by examining the extrusion molding conditions.

<<Configuration of RF tag>>
The RF tag of the present invention is constructed by sandwiching an antenna and an IC chip made of the high-frequency dielectric material as described above. Therefore, the RF tag of the present invention has excellent high-frequency characteristics, and can perform good non-contact communication even at frequencies in the 2.45 GHz band, for example. The present invention also includes the RF tag configured as described above, which is an RF tag for contactless communication using a frequency in the 2.45 GHz band conforming to ISO/IEC 18000-4.

In a preferred embodiment of the RF tag of the present invention, as shown in FIG. 2 described above, in at least one of the high-frequency dielectrics 13 sandwiching the antenna 12 and the IC chip 11, the side contacting the antenna 12 and the IC chip 11 has An adhesive layer 15 is provided. With such a configuration, there is no risk of misalignment of the IC chip 11 and the antenna 12 within the RF tag 1 and erroneous data transmission associated therewith. Although two layers of high-frequency dielectrics are used in FIG. 2, the RF tag of the present invention is not limited to such an embodiment, and may have three or more layers of high-frequency dielectrics. In addition, the plurality of high-frequency dielectrics may have the same shape, such as thickness, and may have different materials.

<Adhesive layer>
Here, the material used for the adhesive layer is not particularly limited, and various known adhesive materials can be used. It is also possible to use a commercially available adhesive, double-sided tape, or the like. Adhesive materials having a low dielectric constant, such as styrene-butadiene copolymers, styrene-isoprene copolymers and hydrides thereof, ethylene-vinyl acetate copolymers, acrylic acid ester adhesives, and polyolefin adhesives are preferred. agent, petroleum resin, etc. Such materials do not impair the high-frequency characteristics of the RF tag of the present invention. Water-based adhesive materials and heat-seal type adhesives that do not adversely affect the human body and IC chips are also preferred. Particularly preferably, SBR latex, SBS emulsion, ethylene-vinyl acetate emulsion, polyolefin emulsion and the like are used. These adhesive materials may contain the above-described inorganic substance powder for high-frequency dielectrics and various additives.

<Adhesive layer>
In a preferred embodiment of the RF tag of the present invention, as shown in FIG. 2, an adhesive is applied to the surface (outer surface of the RF tag) of one high-frequency dielectric 14 that is not in contact with the IC chip 11 and the antenna 12. Layer 16 and release material layer 17 are applied. With such an embodiment, it is easy to attach to goods, clothing, and the like. Especially in the embodiment shown in FIG. 2, since the IC chip 11 and the antenna 12 are not bonded to the high-frequency dielectric 14 on the side having the adhesive layer 16, there is an advantage that they are less likely to be adversely affected by the movement or deformation of the adherend. Therefore, the RF tag of these embodiments is particularly useful for attachment to easily deformable or highly elastic products such as clothing and aluminum cans.

Here, the material used for the adhesive layer is not particularly limited, and various known adhesives can be used. However, materials similar to the adhesive material, such as SBR latex, SBS emulsion, polyolefin emulsion, etc., are preferable from the viewpoint of the high frequency characteristics of the RF tag and the fact that they do not adversely affect the human body. These pressure-sensitive adhesives can also contain the inorganic substance powder for high-frequency dielectrics and various additives. A release material layer 17 is preferably attached to the outside of the adhesive layer 16 for convenience during storage, transportation and use. The material of the release material layer is not particularly limited, and various known release agents can be used.

The present invention will be described in more detail below based on examples. It should be noted that these Examples are intended to provide specific aspects and embodiments in order to facilitate an understanding of the concept and scope of the present invention disclosed herein and recited in the appended claims. For illustrative purposes only, the present invention is in no way limited to these examples.

In the following examples, various high-frequency dielectrics were prepared from the following raw materials, and RF tags were produced using these high-frequency dielectrics as base sheets. The following characteristic evaluations were performed on the manufactured RF tag, raw material and each high-frequency dielectric.

(Average particle size of inorganic substance powder)
Using a specific surface area measuring device SS-100 manufactured by Shimadzu Corporation, it was calculated from the results of measuring the specific surface area by the air permeation method in accordance with JIS M-8511.

(Specific surface area of inorganic substance powder)
Using BELSORP-mini manufactured by Microtrac BELL, it was determined by the nitrogen gas adsorption method.

(Roundness of inorganic powder)
100 particles are sampled so as to represent the particle size distribution of the powder, and the projection of each particle obtained using an optical microscope is image analyzed using commercially available image analysis software. asked for As the measurement principle, the projected area and the projected perimeter of the particle are measured and defined as (A) and (PM), respectively. Let (B) be the area of a circle with the same perimeter as the projected perimeter of
Roundness=A/B=A×4π/(PM) ²
is a request.

(Tensile properties of high frequency dielectric)
Tensile strength and elongation at break were measured using Autograph AG-100kNXplus (Shimadzu Corporation) under conditions of 23° C. and 50% RH in accordance with JIS K 7161-2:2014. A dumbbell-shaped test piece was cut out from a molded product described later. The drawing speed was 50 mm/min.

(Electrical properties of high frequency dielectric)
Permittivity and dielectric loss tangent were measured at 25° C. using a cavity resonator at a frequency of 1 GHz in accordance with JIS 2565.
The volume resistivity was measured in accordance with JIS K 6921-2:2018 using a resistivity meter MCP-HT800 manufactured by Nitto Seiko Analyticc Co., Ltd.

(Communication characteristics of RF tag)
Data was transmitted and received 10 times at a frequency of 2.45 GHz band from a reader/writer positioned 1.5 m away from each RF tag test body, and it was checked whether there was any problem in reading and writing data. Two RF tag specimens were tested for each example and comparative example, and evaluated according to the following criteria.
· ⊚: Both of the two specimens had no problem in reading and writing data.
◯: One of the test specimens had no problem in reading and writing data, and the other specimen successfully communicated eight times or more.
.DELTA.: In one test sample, data reading and writing was hindered three times or more.
x: There were cases where data reading and writing was hindered for both of the two specimens.

(raw materials)
Raw materials used in the following examples and comparative examples were as follows.
- Thermoplastic resin PP: polypropylene homopolymer (manufactured by Prime Polymer Co., Ltd.: Prime Polypro (registered trademark) E111G, melting point 160 ° C.)

・Inorganic substance powder CC1: heavy calcium carbonate particles (no surface treatment), average particle diameter 1.10 μm, specific surface area 32,000 cm ² /g, circularity: 0.55
CC2: Heavy calcium carbonate particles (no surface treatment) Average particle size 3.60 µm, specific surface area 6,000 cm2/g, circularity: 0.90
CC3: Heavy calcium carbonate particles (no surface treatment) Average particle diameter 2.2 μm, specific surface area 10,000 cm ² /g, circularity: 0.85
CC4: Heavy calcium carbonate particles (fatty acid surface treatment) Average particle diameter 2.2 μm, specific surface area 10,000 cm ² /g, circularity: 0.85
MgO: Magnesium oxide fine particles, average particle size 0.2 μm

・ Additive D (antistatic agent): PC-4 (lithium salt) manufactured by Marubishi Yuka Kogyo Co., Ltd.
E (lubricant): magnesium stearate F1 (antioxidant): Adekastab (registered trademark) AO-60 (phenolic antioxidant) manufactured by ADEKA Co., Ltd.
F2 (antioxidant): Adekastab (registered trademark) 2112 (phosphite antioxidant) manufactured by ADEKA Co., Ltd.

Adhesive AD: ethylene-vinyl acetate water-based emulsion manufactured by Wacker Chemical Co.

[Example 1]
(Preparation of high frequency dielectric sheet)
Among the above raw materials, 40 parts by mass of PP, 40 parts by mass of CC1, 20 parts by mass of CC2, and 1 part by mass each of additives D, E, F1, and F2 were mixed with a co-rotating machine manufactured by Parker Corporation. The mixture was put into a twin-screw kneading extruder HK-25D (φ25 mm, L/D=41), extruded into strands at a cylinder temperature of 190 to 200° C., cooled, and cut into pellets.

The pellets prepared as described above are extruded at 220°C by a Laboplastmill single-screw T-die extruder (φ20 mm, L/D = 25) manufactured by Toyo Seiki Seisakusho Co., Ltd., so that the pellets are 4 times larger in the take-up direction. Then, it was stretched at 190° C. to form a sheet having a thickness of about 150 μm. The obtained sheet was evaluated for tensile properties and electrical properties by the test methods described above. The evaluation results are shown in Table 1 below together with the blending of raw materials and moldability.

(Production of RF tag)
A commercially available RF tag (passive type for 2.45 GHz, size: 22×50 mm) was disassembled to take out the IC chip and antenna, which were sandwiched between the high-frequency dielectric sheets prepared as described above. First, the above high-frequency dielectric sheet was cut into a size of 22×50 mm, and an adhesive AD was applied to one side surface. Further, the IC chip and antenna taken out as described above were placed in the same positions as in the original commercial RF tag, and left at about 40° C. for one day and night to adhere. A sheet of the same size cut from the above high-frequency dielectric material was put on the sheet, and four pieces were heat-sealed to prepare an RF tag test piece. Two RF tag specimens were produced by the same operation.

[Comparative Example 1]
The same method as in Example 1 was used to evaluate the communication characteristics of the same two commercially available RF tags used in Example 1. FIG. However, in order to arrange the conditions, the commercially available RF tag was left at about 40° C. for one day and night before the evaluation. Evaluation results are shown in Table 1 below.

[Examples 2 to 4, Comparative Examples 2 to 4]
A high-frequency dielectric sheet and an RF tag specimen were produced and evaluated in the same manner as in Example 1, except that the composition of the high-frequency dielectric sheet and the stretching method were changed as shown in Table 1. Evaluation results and the like are shown in Table 1 below.

According to the present invention, a polyolefin resin and a heavy calcium carbonate powder are contained in a mass ratio of 50:50 to 10:90, and the dielectric constant ε at 1 GHz / 25 ° C. is 5 or less and the dielectric loss tangent tan δ is 5 × The RF tags of Examples 1 to 4 using a high-frequency dielectric of 10 ⁻⁴ or less as a base sheet all exhibited good communication characteristics at frequencies in the 2.45 GHz band. On the other hand, in the commercially available RF tag of Comparative Example 1 using a PET resin as a base sheet and the RF tags of Comparative Examples 2 to 4 made from a base sheet containing no or a small amount of heavy calcium carbonate, data reading and writing was hindered.

Moreover, in Examples 1 to 4 according to the present invention, the high-frequency dielectric sheets not only exhibited good dielectric constants and dielectric loss tangents, but were also excellent in formability and tensile properties. In particular, in Example 1, in which two groups of ground calcium carbonate powders having different average particle sizes were blended, and in Example 4, in which surface-treated ground calcium carbonate powder was blended, such an advantage was remarkable. It has been found that the RF tag according to the present invention combines excellent communication properties with good mechanical properties.

[Example 5]
The same operations as in Examples 1 and 2 were performed, except that 40 parts by weight of PP, 60 parts by weight of CC4, and 1 part by weight each of additives E, F1, and F2 were used as raw materials. Evaluation results and the like are shown in Table 2 below.

[Example 6]
The same operation as in Example 5 was performed, except that the uniaxial stretching was not performed. Evaluation results and the like are shown in Table 2 below.

[Example 7]
The same procedure as in Example 5 was followed, except that the sheet was not stretched after extrusion, but was instead vacuum pressed to form a sheet with a thickness of about 220 μm. Evaluation results and the like are shown in Table 2.

Examples 5 and 6 showed that the stretching operation improved the high-frequency characteristics of the high-frequency dielectric sheet and the communication characteristics of the RF tag. Further, from Example 7, it was shown that if the porosity is less than 5%, the communication characteristics may be slightly inferior to the RF tag provided with the high-frequency dielectric sheet with the same formulation but different porosity. .

As shown by the above examples, the present invention provides an RF tag having both good communication characteristics and mechanical characteristics. The RF tag of the present invention is advantageous in terms of cost because the high-frequency dielectric sheet, which is a constituent material, is mainly made of polyolefin resin and heavy calcium carbonate powder.

1 RF tag 11 IC chip 12 antenna 13 high frequency dielectric 14 high frequency dielectric 15 adhesive layer 16 adhesive layer 17 release material layer

Claims (7)

In an RF tag in which an antenna and an IC chip are sandwiched between high-frequency dielectrics,
The high-frequency dielectric contains polyolefin resin and heavy calcium carbonate powder at a mass ratio of 40:60 to 10:90, and has a dielectric constant ε of 5 or less at a frequency of 1 GHz or higher and a temperature of 25 ° C. , the dielectric loss tangent tan δ is 5×10 ⁻⁴ or less, and the porosity of the high frequency dielectric is 24% or more and 29% or less, wherein the method for manufacturing the high frequency dielectric applied to the RF tag, ,
After obtaining a base sheet containing the polyolefin resin and the heavy calcium carbonate powder at a mass ratio of 40:60 to 10:90, the stretch ratio is 1.1 times or more and 10.0 times or less. A method for producing a high-frequency dielectric for an RF tag, wherein the base sheet is stretched. 2. The method for producing a high-frequency dielectric for an RF tag according to claim 1, wherein said polyolefin resin is polypropylene resin and/or polyethylene resin. 3. The method of manufacturing a high-frequency dielectric for an RF tag according to claim 1, wherein the ground calcium carbonate powder is surface-treated ground calcium carbonate powder. The high frequency for RF tag according to any one of claims 1 to 3, wherein the heavy calcium carbonate powder has an average particle size of 0.7 μm or more and 7.0 μm or less by an air permeation method according to JIS M-8511. A method of manufacturing a dielectric. The heavy calcium carbonate powder has a BET specific surface area of 0.1 m ² /g or more and 10.0 m ² /g or less, and a circularity of 0.50 or more and 0.95 or less. A method of manufacturing a high-frequency dielectric for RF tags according to 1. The heavy calcium carbonate powder contains at least two groups of particles having different average particle sizes, and the at least two groups of particles having different average particle sizes are averaged by an air permeation method according to JIS M-8511. A first calcium carbonate particle group having a particle size of 0.7 μm or more and less than 2.2 μm, and a second calcium carbonate particle group having an average particle size of 2.2 μm or more and 7.0 μm or less measured by an air permeation method according to JIS M-8511. and in a mass ratio of 1: 1 to 5: 1,
A method for manufacturing a high-frequency dielectric for RF tags according to any one of claims 1 to 5. 7. The a/b ratio is 0.85 or less, where a is the average particle size of the first calcium carbonate particle group and b is the average particle size of the second calcium carbonate particle group. a method of manufacturing a high frequency dielectric for RF tags.

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