KR102782992B1 - Biaxially oriented polyphenylene sulfide film and preperation method thereof - Google Patents

Abstract

The biaxially oriented polyphenylene sulfide film according to the embodiment includes a polyphenylene sulfide resin layer having a specific range of overall average linearity (TL), and satisfies a dielectric constant at a frequency of 10 GHz, a coefficient of thermal expansion (CTE) in the range from 30°C to 80°C, and a modulus, respectively, thereby simultaneously improving thermal properties, electrical properties, and mechanical properties, and can be usefully utilized in a flexible copper clad laminate (FCCL), and in particular, can be applied to high-frequency applications of 5G to implement excellent properties.

Description

Biaxially oriented polyphenylene sulfide film and preparation method thereof {BIAXIALLY ORIENTED POLYPHENYLENE SULFIDE FILM AND PREPERATION METHOD THEREOF}

The invention relates to a biaxially oriented polyphenylene sulfide film and a method for producing the same.

Flexible Copper Clad Laminate (FCCL) is used in digital home appliances such as mobile phones, digital camcorders, laptops, and LCD monitors. Demand for FCCL has been rapidly increasing recently due to its flexibility and its advantages in lightness, thinness, and compactness.

These FCCLs are characterized by their flexibility, as they are made by laminating a polymer film layer and a metal conductive layer. The FCCLs are particularly used in electronic devices or material parts of electronic devices that require flexibility or bendability, and are contributing to the miniaturization and weight reduction of electronic devices.

The use of flexible printed circuit boards (FPCBs) containing heat-resistant resins such as polyethylene terephthalate (PET) or polyimide (PI), which are flexible materials for the above FCCL, is increasing.

Meanwhile, with the recent active use of 5G, materials with high heat resistance, low dielectric constant, and low dielectric loss are required because they use higher frequencies than before.

However, PET, which is a soft material, has limited heat resistance, and PI has large electrical loss and limited satisfactory low permittivity characteristics, so there may be a problem that its use is limited.

Korean Publication Patent No. 2016-0146195

The implementation is designed to solve the problems of the prior art described above.

The embodiment aims to provide a biaxially oriented polyphenylene sulfide film which can simultaneously improve thermal properties such as high heat resistance, electrical properties such as low permittivity and dielectric loss, and mechanical properties such as tensile strength, elongation, and modulus compared to conventional biaxially oriented films.

In addition, the present invention aims to provide a method for manufacturing the biaxially oriented polyphenylene sulfide film capable of implementing the above characteristics in an economical and efficient manner.

To achieve the above object, one embodiment provides a biaxially oriented polyphenylene sulfide film, which includes a polyphenylene sulfide resin layer including a polyphenylene sulfide resin, wherein the polyphenylene sulfide resin layer has an overall average linearity (TL) of 0.689 or more, a dielectric constant at a frequency of 10 GHz of 3.50 Dk or less, a coefficient of thermal expansion (CTE) in the range of 30°C to 80°C of 20 ppm/°C to 50 ppm/°C, and a modulus of 360 kg/mm2 or more.

Another embodiment provides a method for producing a biaxially oriented polyphenylene sulfide film, comprising: a first step of melt-extruding a polyphenylene sulfide resin to produce a sheet; and a second step of biaxially oriented the sheet in the longitudinal and transverse directions and heat-setting the sheet, wherein the polyphenylene sulfide resin layer includes the polyphenylene sulfide resin, and the polyphenylene sulfide resin layer has an overall average linearity (TL) of 0.689 or more, a dielectric constant at a frequency of 10 GHz of 3.50 Dk or less, a coefficient of thermal expansion (CTE) in the range of 30°C to 80°C of 20 ppm/°C to 50 ppm/°C, and a modulus of 360 kg/mm2 or more.

The biaxially oriented polyphenylene sulfide film according to the embodiment includes a polyphenylene sulfide resin layer having a specific range of overall average linearity (TL), and satisfies a dielectric constant at a frequency of 10 GHz in a specific range, a coefficient of thermal expansion (CTE) in the range of 30°C to 80°C, and a modulus, thereby simultaneously improving thermal properties, electrical properties, and mechanical properties, and can be usefully utilized in flexible copper clad laminates (FCCLs), etc., and can implement excellent properties especially when applied to high-frequency applications of 5G.

In addition, the method for manufacturing the biaxially oriented polyphenylene sulfide film according to the embodiment is an economical and efficient method, and can provide a biaxially oriented polyphenylene sulfide film capable of implementing the above characteristics, and can further improve processability and productivity.

Figure 1 is a cross-sectional view of a biaxially stretched polyphenylene sulfide film according to one embodiment.
Figure 2 is a cross-sectional view of a biaxially stretched polyphenylene sulfide film according to another embodiment.
Figure 3 is a cross-sectional view of a biaxially stretched polyphenylene sulfide film according to another embodiment.
Figure 4 schematically illustrates a method for manufacturing a biaxially stretched polyphenylene sulfide film according to one embodiment.
Figure 5 schematically illustrates a method for manufacturing a biaxially stretched polyphenylene sulfide film according to another embodiment.

Hereinafter, the invention will be described in detail through implementation examples. The implementation examples are not limited to the contents disclosed below and may be modified in various forms as long as the gist of the invention is not changed.

In this specification, when a part is said to "include" a certain component, this does not mean that other components are excluded, but rather that other components may be included, unless otherwise specifically stated.

In this specification, singular expressions are interpreted to include the singular or plural as interpreted by the context, unless otherwise specified.

In addition, it should be understood that all numerical ranges indicating the physical property values, dimensions, reaction conditions, etc. of the components described in this specification are modified by the term "about" in all cases unless otherwise specified.

Meanwhile, in this specification, the terms first layer, second layer, or first, second, etc. are used to describe various components, and the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

In addition, the criteria for "one side"/"the other side" or "upper"/"lower" of each component are explained based on the drawing, and these terms are only terms for distinguishing components and can be interchangeable in actual application.

When it is described in this specification that one component is formed on or below another component, it includes both that one component is formed directly on or below the other component, or indirectly through the interposition of another component.

[Biaxially stretched polyphenylene sulfide film]

In one embodiment, a biaxially oriented polyphenylene sulfide film is provided, which includes a polyphenylene sulfide resin layer including a polyphenylene sulfide resin, wherein the polyphenylene sulfide resin layer has an overall average linearity (TL) of 0.689 or more, a dielectric constant at a frequency of 10 GHz of 3.50 Dk or less, a coefficient of thermal expansion (CTE) in the range of 30°C to 80°C of 20 ppm/°C to 50 ppm/°C, and a modulus of 360 kg/mm2 or more.

The biaxially oriented polyphenylene sulfide film according to the embodiment includes a polyphenylene sulfide resin layer having a specific range of overall average linearity (TL), and satisfies specific ranges of dielectric constant, coefficient of thermal expansion (CTE) in the range of 30°C to 80°C, and modulus, thereby simultaneously improving thermal properties, electrical properties, and mechanical properties, and thus can be usefully utilized in a metal-clad laminate, and in particular, can be utilized for high-frequency applications of 5G to provide excellent effects.

Hereinafter, each layer, type and physical properties of each resin constituting the biaxially stretched polyphenylene sulfide film according to an implementation example are specifically described.

Polyphenylene sulfide resin layer

According to one embodiment, the biaxially oriented polyphenylene sulfide film includes a polyphenylene sulfide resin layer including a polyphenylene sulfide resin, and the overall average linearity (TL) of the polyphenylene sulfide resin layer is 0.689 or greater.

The overall average linearity (TL) of the polyphenylene sulfide resin layer can be used as an indicator of the molecular weight of the resin included in the resin layer or the molecular structure, such as linear, branched, or cross-linked.

Typically, a value of linearity close to 0 indicates that the molecular structure of the resin contains many branched or cross-linked structures, and as this value increases, it indicates that the molecular structure of the resin contains many straight chain structures.

The overall average linearity (TL) of the polyphenylene sulfide resin layer may vary depending on the type of each resin included in the polyphenylene sulfide resin layer, their linearity, the mixing ratio of these mixed resins, and the thickness ratio of each resin layer constituting the polyphenylene sulfide resin layer.

Specifically, the polyphenylene sulfide resin layer may include one type of polyphenylene sulfide resin, a mixed resin of two or more types of polyphenylene sulfide resins, or a polyphenylene sulfide resin layer of one layer (monolayer) or two or more layers (multilayer), and the overall average linearity (TL) may vary depending on the components constituting the polyphenylene sulfide resin layer, its structure, and the thickness ratio of each of these resin layers, or, when the polyphenylene sulfide resin layer includes a mixed resin, the mixing ratio of these resins. In addition, the overall average linearity (TL) may have a significant effect on the thermal properties, electrical properties, and mechanical properties of the biaxially oriented polyphenylene sulfide film.

Therefore, when the overall average linearity (TL) of the polyphenylene sulfide resin layer is controlled within a specific range, the thermal properties, electrical properties, and mechanical properties of the biaxially stretched polyphenylene sulfide film can be simultaneously improved, thereby further expanding its utility.

According to one embodiment, the polyphenylene sulfide resin layer may include one type of polyphenylene sulfide resin.

In this case, the overall average linearity (TL) of the polyphenylene sulfide resin layer may mean the linearity of the polyphenylene sulfide resin.

The above linearity is a value obtained by measuring the melt viscosity of the resin at frequencies of 100 rad/s and 400 rad/s at approximately 330°C using a rheometer, and comparing the degree of shear thinning using the ratio of these values, and can be expressed by the following Equation 1.

[Formula 1]

Linearity = (melt viscosity of resin at frequency 400 rad/s) / (melt viscosity of resin at frequency 100 rad/s).

The above linearity can affect thermal properties such as heat resistance, electrical properties such as permittivity and dielectric loss, and mechanical properties such as tensile strength, elongation, and modulus.

According to another embodiment, the polyphenylene sulfide resin layer may include a mixed resin of two or more types of polyphenylene sulfide resins.

In this case, the overall average linearity (TL) of the polyphenylene sulfide resin layer may vary depending on the type of each polyphenylene sulfide resin (individual polyphenylene sulfide resin) included in the polyphenylene sulfide resin layer, their linearity, and the mixing ratio of these mixed resins. At this time, the linearity of each polyphenylene sulfide resin (individual polyphenylene sulfide resin) can be obtained using the above equation 1.

According to one embodiment, the overall average linearity (TL) of the polyphenylene sulfide resin layer can be expressed by the following Equation 2.

[Formula 2]

In the above equation 2,

The above L _k is the linearity of the individual polyphenylene sulfide resins included in the mixed resin,

The above W _k is the weight ratio of the individual polyphenylene sulfide resin to the total weight of the mixed resin (weight of the individual polyphenylene sulfide resin/total weight of the mixed resin).

Specifically, the above equation 2 can be expressed as the following equation 2-1.

[Formula 2-1]

TL = (L ₁ × W ₁ ) + (L ₂ × W ₂ ) + ··· (L _n × W _n )

In the above equation 2-1,

The above L ₁ is the linearity of the first polyphenylene sulfide resin,

The above L ₂ is the linearity of the second polyphenylene sulfide resin,

The above L _n is the linearity of the nth polyphenylene sulfide resin,

The above W ₁ is the weight ratio of the first polyphenylene sulfide resin to the total weight of the mixed resin (weight of the first polyphenylene sulfide resin/total weight of the mixed resin),

The above W ₂ is the weight ratio of the second polyphenylene sulfide resin to the total weight of the mixed resin (weight of the second polyphenylene sulfide resin/total weight of the mixed resin),

The above W _n is the weight ratio of the nth polyphenylene sulfide resin to the total weight of the mixed resin (weight of the nth polyphenylene sulfide resin/total weight of the mixed resin).

Specifically, the overall average linearity (TL) is the sum of the values obtained by calculating the linearity (L ₁ , L ₂ , ... L _n ) of each polyphenylene sulfide resin (e.g., the first polyphenylene sulfide resin and the second polyphenylene sulfide resin, etc.) included in the mixed resin, and then multiplying the individual linearity by the weight ratio (W ₁ , W ₂ , ... W _n ) of the individual polyphenylene sulfide resin with respect to the total weight of the mixed resin.

The overall average linearity (TL) of such polyphenylene sulfide resin layers can have a significant effect on the mechanical properties such as tensile strength, elongation, and modulus, as well as the stretchability of the film.

According to another embodiment, the polyphenylene sulfide resin layer may include one layer (single layer) or two or more layers of polyphenylene sulfide resin layers. Specifically, the polyphenylene sulfide resin layer may include two or more co-extruded polyphenylene sulfide resin layers.

Here, coextrusion means a method of melting different or similar materials through a plurality of extruders, extruding them in a multilayer molten state through a feedblock method or a multi-manifold method, and then producing a multilayer sheet, film, or laminate through a stretching process, a blowing process, or a cast process.

According to an embodiment, the biaxially stretched polyphenylene sulfide film may include two or more polyphenylene sulfide resin layers including the first polyphenylene sulfide resin layer and the second polyphenylene sulfide resin layer by melt-coextruding each resin included in the first polyphenylene sulfide resin layer and the second polyphenylene sulfide resin layer using a plurality of extruders and then performing a biaxial stretching process.

For example, in the case of including two or more co-extruded polyphenylene sulfide resin layers, the functional aspect of controlling the physical properties of the film, such as stretchability, strength, and elongation, as well as the economic aspect of the product can be satisfied at the same time.

The overall average linearity (TL) of the co-extruded polyphenylene sulfide resin layer can be calculated by using the linearity of each polyphenylene sulfide resin (individual polyphenylene sulfide resin) included in each polyphenylene sulfide resin layer in the co-extruded polyphenylene sulfide resin layer, such as the first polyphenylene sulfide resin and the second polyphenylene sulfide resin. At this time, the linearity of each polyphenylene sulfide resin (individual polyphenylene sulfide resin) can be obtained using the above equation 1.

In addition, the overall average linearity (TL) may vary depending on the type of resin included in each polyphenylene sulfide resin layer, their linearity, and the thickness ratio of each resin layer constituting the co-extruded polyphenylene sulfide resin layer.

According to one embodiment, the overall average linearity (TL) of the polyphenylene sulfide resin layer, for example, the coextruded polyphenylene sulfide resin layer, can be expressed by the following Equation 3.

[Formula 3]

In the above equation 3,

The above L _k is the linearity of the individual polyphenylene sulfide resin contained in the individual polyphenylene sulfide resin layer,

The above T _k is the thickness ratio of the individual polyphenylene sulfide resin layer to the total thickness of the coextruded polyphenylene sulfide resin layer (thickness of the individual polyphenylene sulfide resin layer/total thickness of the coextruded polyphenylene sulfide resin layer).

Specifically, the above equation 3 can be expressed as the following equation 3-1.

[Formula 3-1]

TL = (L ₁ × T ₁ ) + (L ₂ × T ₂ ) + ··· (L _n × T _n )

In the above equation 3-1,

The above L ₁ is a linearity of the first polyphenylene sulfide resin included in the first polyphenylene sulfide resin layer,

The above L ₂ is a linearity of the second polyphenylene sulfide resin included in the second polyphenylene sulfide resin layer,

The above L _n is the linearity of the nth polyphenylene sulfide resin included in the nth polyphenylene sulfide resin layer,

The above T ₁ is a thickness ratio of the first polyphenylene sulfide resin layer to the total thickness of the co-extruded polyphenylene sulfide resin layer (thickness of the first polyphenylene sulfide resin layer/total thickness of the co-extruded polyphenylene sulfide resin layer),

The above T ₂ is a thickness ratio of the second polyphenylene sulfide resin layer to the total thickness of the co-extruded polyphenylene sulfide resin layer (thickness of the second polyphenylene sulfide resin layer/total thickness of the co-extruded polyphenylene sulfide resin layer),

The above T _n is a thickness ratio of the nth polyphenylene sulfide resin layer to the total thickness of the coextruded polyphenylene sulfide resin layer (thickness of the nth polyphenylene sulfide resin layer/total thickness of the coextruded polyphenylene sulfide resin layer).

Specifically, the overall average linearity (TL) is the sum of the values obtained by obtaining the linearity (L ₁ , L ₂ , ... L _n ) of each polyphenylene sulfide resin (e.g., the first polyphenylene sulfide resin and the second polyphenylene sulfide resin, etc.) included in the individual polyphenylene sulfide resin layers, and then multiplying the linearity (L ₁ , L ₂ , ... L _n ) of each polyphenylene sulfide resin by the thickness ratio (T ₁ , T ₂ , ... T _n ) of the individual polyphenylene sulfide resin layer to the total thickness of the co-extruded polyphenylene sulfide resin layer.

The overall average linearity (TL) of the above polyphenylene sulfide resin layer can have a significant effect on the mechanical properties such as tensile strength, elongation, and modulus, as well as the stretchability of the film.

The overall average linearity (TL) of the polyphenylene sulfide resin layer may be 0.689 or more, 0.690 or more, 0.691 or more, 0.692 or more, 0.693 or more, 0.694 or more, 0.695 or more, or 0.696 or more. The overall average linearity (TL) of the polyphenylene sulfide resin layer may be 0.750 or less, 0.740 or less, 0.730 or less, 0.725 or less, 0.724 or less, 0.723 or less, 0.721 or less, 0.720 or less, 0.710 or less, 0.708 or less, 0.706 or less, 0.705 or less, 0.703 or less, 0.701 or less, 0.700 or less, less than 0.700, or 0.699 or less. Specifically, the overall average linearity (TL) of the polyphenylene sulfide resin layer may be 0.689 to 0.750, 0.689 to 0.740, 0.689 to 0.730, 0.689 to 0.725, 0.689 to 0.721, 0.689 to 0.720, 0.689 to 0.710, 0.690 to 0.710, 0.692 to 0.710, 0.693 to 0.705, 0.695 to 0.705, or 0.695 to 0.700.

When the above polyphenylene sulfide resin layer satisfies the overall average linearity (TL) of the above range, the molecular structure of the polyphenylene sulfide resin has a higher proportion of linear than cross-linked structures (cross-linked types), so that high impact resistance and low water absorption (hygroscopicity) of the film can be realized. In addition, it has great technical significance in that it can simultaneously improve mechanical properties such as tensile strength, elongation, and modulus, and provide stretchability suitable for film use with high melt strength.

The polyphenylene sulfide resin included in the above polyphenylene sulfide resin layer is a high molecular polymer having a chemical structure in which sulfur is bonded to a benzene ring, and can have excellent chemical resistance and excellent heat resistance.

The above polyphenylene sulfide resin layer may have various structures, and depending on these various structures, the linearity of the polyphenylene sulfide resin and/or the overall average linearity (TL) of the polyphenylene sulfide resin layer may be adjusted to have an optimal linearity.

For example, the polyphenylene sulfide resin layer may include one or more types of polyphenylene sulfide resin.

Specifically, the polyphenylene sulfide resin layer may include one type of polyphenylene sulfide resin.

When the above polyphenylene sulfide resin layer includes one type of polyphenylene sulfide resin, the linearity of the polyphenylene sulfide resin may be 0.689 or more, 0.690 or more, 0.691 or more, 0.692 or more, 0.693 or more, 0.694 or more, 0.695 or more, or 0.696 or more. The linearity of the above polyphenylene sulfide resin may be 0.750 or less, 0.740 or less, 0.730 or less, 0.725 or less, 0.724 or less, 0.723 or less, 0.721 or less, 0.720 or less, 0.710 or less, 0.708 or less, 0.706 or less, 0.705 or less, 0.703 or less, 0.701 or less, 0.700 or less, less than 0.700, or 0.699 or less. Specifically, the linearity of the polyphenylene sulfide resin may be 0.689 to 0.750, 0.689 to 0.740, 0.689 to 0.730, 0.689 to 0.725, 0.689 to 0.721, 0.689 to 0.720, 0.689 to 0.710, 0.690 to 0.710, 0.692 to 0.710, 0.693 to 0.705, 0.695 to 0.705, or 0.695 to 0.700. At this time, the overall average linearity of the polyphenylene sulfide resin layer may be the same as or similar to the range of the linearity of the polyphenylene sulfide resin.

Additionally, the polyphenylene sulfide resin layer may include two or more types of polyphenylene sulfide resins.

Specifically, the polyphenylene sulfide resin layer includes a mixed resin of a first polyphenylene sulfide resin and a second polyphenylene sulfide resin, and the first polyphenylene sulfide resin and the second polyphenylene sulfide resin may have different linearities.

The linearity of the first polyphenylene sulfide resin may be 0.710 or more to 0.770 or less, 0.710 or more to 0.765 or less, 0.720 or more to 0.760 or less, 0.730 or more to 0.750 or less, 0.730 or more to 0.745 or less, 0.735 or more to 0.745 or less, or 0.736 or more to 0.743 or less.

In addition, the linearity of the second polyphenylene sulfide resin may be 0.680 or more and less than 0.710, 0.680 or more and 0.705 or less, 0.680 or more and 0.703 or less, 0.680 or more and 0.700 or less, 0.680 or more and 0.699 or less, 0.680 or more and 0.695 or less, 0.682 or more and 0.692 or less, or 0.682 or more and 0.690 or less.

When the linearity of the first polyphenylene sulfide resin and the second polyphenylene sulfide resin each satisfies the above range, it may be more advantageous in implementing the desired effect.

When the above polyphenylene sulfide resin layer includes two or more types of polyphenylene sulfide resins, the weight ratio of the first polyphenylene sulfide resin and the second polyphenylene sulfide resin may be very important.

According to an embodiment, the weight ratio of the first polyphenylene sulfide resin and the second polyphenylene sulfide resin may be 10:90 to 50:50, 10:90 to 40:60, 10:90 to 30:70, 15:85 to 40:60, 20:80 to 40:60, 20:80 to 30:70, 15:85 to 30:70, 15:85 to 25:75.

When the weight ratio of the first polyphenylene sulfide resin and the second polyphenylene sulfide resin satisfies the above range, it is more advantageous in satisfying the overall average linearity (TL) of the specific range of the polyphenylene sulfide resin layer, and in this case, the desired electrical properties, mechanical properties, and thermal properties can be improved simultaneously.

Additionally, the melt viscosity of the mixed resin may be 2,000 poise to 4,000 poise, 2,000 poise to 3,500 poise, 2,000 poise to 3,000 poise, 2,500 poise to 3,800 poise, 2,700 poise to 3,800 poise, 2,800 poise to 3,800 poise, 3,000 poise to 3,800 poise, or 3,200 poise to 3,800 poise.

In this specification, the melt viscosity is measured at 330°C using a rotating disk viscometer, and can be defined as the viscosity at an angular frequency of 1.99 rad/s when the viscosity is measured in an angular frequency range of 0.6 to 500 rad/s using a frequency sweep method.

When the above melting viscosity satisfies the above range, it may be more advantageous in implementing the desired effect.

The melt viscosity of the first polyphenylene sulfide resin may be 1,000 poise to 30,000 poise, 1,500 poise to 25,000 poise, 2,000 poise to 20,000 poise, 2,500 poise to 15,000 poise, or 3,000 poise to 10,000 poise.

The melt viscosity of the second polyphenylene sulfide resin may be 1,000 poise to 25,000 poise, 1,500 poise to 20,000 poise, 1,800 poise to 15,000 poise, 2,000 poise to 10,000 poise, or 2,000 poise to 7,000 poise.

In addition, the mixed resin may have a melting point of 270° C. to 290° C., 272° C. to 288° C., 275° C. to 285° C., or 278° C. to 283° C. The melting point in the present specification may be measured using a differential scanning calorimeter (DSC) by heating from 30° C. to 320° C. at a rate of 10° C./min, maintaining the temperature under isothermal conditions for 5 minutes, cooling to 30° C., and then heating again from 30° C. to 320° C. at a rate of 10° C./min.

The first polyphenylene sulfide resin may have a melting point of 270°C to 290°C, 272°C to 288°C, 275°C to 285°C, or 278°C to 283°C.

The second polyphenylene sulfide resin may have a melting point of 270°C to 290°C, 272°C to 288°C, 275°C to 285°C, or 278°C to 283°C.

The above mixed resin may have a crystallization temperature of 125°C to 150°C, 128°C to 147°C, 131°C to 144°C, or 133°C to 140°C. In the present specification, the crystallization temperature may be measured using a differential scanning calorimeter by heating from 30°C to 320°C at a rate of 10°C/min, cooling to 30°C, then heating again from 30°C to 320°C at a rate of 10°C/min, and then cooling to 30°C at 10°C/min.

The first polyphenylene sulfide resin may have a crystallization temperature of 129°C to 146°C, 131°C to 144°C, 133°C to 142°C, or 135°C to 140°C.

The second polyphenylene sulfide resin may have a crystallization temperature of 127°C to 144°C, 129°C to 142°C, 131°C to 140°C, or 133°C to 138°C.

When the first polyphenylene sulfide resin, the second polyphenylene sulfide resin and the mixed resin each satisfy the melting viscosity, melting point and crystallization temperature within the above ranges, it is very advantageous in satisfying the linearity of each resin and/or the overall average linearity (TL) of the polyphenylene sulfide resin layer, and can simultaneously improve the high impact resistance and mechanical properties such as tensile strength, elongation and modulus of the biaxially oriented polyphenylene sulfide film, and can provide stretchability suitable for film use with high melt strength.

The above mixed resin may have characteristic peaks at 800 to 810 cm ^-1 , 1005 to 1015 cm ^-1 , 1085 to 1095 cm ^-1 , 1380 to 1390 cm ^-1 _, or 1465 to 1475 cm ^-1 when measured by FT-IR spectrum (Fourier-transform infrared spectroscopy).

The above first polyphenylene sulfide resin may have characteristic peaks at 800 to 810 cm ^-1 , 1005 to 1015 cm ^-1 , 1085 to 1095 cm -1 , 1380 to 1390 cm ^-1 _, or 1465 to 1475 cm ^-1 when measured by FT- ^IR spectrum (Fourier-transform infrared spectroscopy).

The above second polyphenylene sulfide resin may have characteristic peaks at 800 to 810 cm ^-1 , 1005 to 1015 cm ^-1 , 1085 to 1095 cm -1 , 1380 to 1390 cm ^-1 _, or 1465 to 1475 cm ^-1 when measured by FT- ^IR spectrum (Fourier-transform infrared spectroscopy).

According to another embodiment, the biaxially oriented polyphenylene sulfide film may further include a resin other than the polyphenylene sulfide resin.

Specifically, the biaxially stretched polyphenylene sulfide film may include a mixed resin including the polyphenylene sulfide resin and a resin other than the polyphenylene sulfide resin.

For example, the mixed resin may include the polyphenylene sulfide resin and the polyester resin. The polyester resin may include, for example, polyethylene terephthalate (PET).

When using a mixed resin of the above polyphenylene sulfide resin and polyester resin, the polyphenylene sulfide resin may be included in an amount of 90 wt% or more, 92 wt% or more, or 93 wt% or more, based on the total weight of the entire mixed resin. The polyester resin may be included in an amount of 10 wt% or less, 8 wt% or less, or 7 wt% or less, based on the total weight of the entire mixed resin.

For example, the mixing weight ratio of the polyphenylene sulfide resin and the polyester resin may be 90 to 100:10 to 0, or 90 to 99.9:10 to 0.1.

Referring to FIG. 1, the biaxially stretched polyphenylene sulfide film (1) may include a polyphenylene sulfide resin layer (10) including a single layer of polyphenylene sulfide resin.

For example, the polyphenylene sulfide resin layer (10) may include polyphenylene sulfide resin.

In addition, the polyphenylene sulfide resin layer (10) may include a mixed resin including the first polyphenylene sulfide resin and the second polyphenylene sulfide resin, or may include a mixed resin including the polyphenylene sulfide resin and a resin other than the polyphenylene sulfide resin.

According to another embodiment, the biaxially stretched polyphenylene sulfide film may be formed of one layer (single layer) including the polyphenylene sulfide resin layer (10), or may form a multilayer structure including two or more coextruded polyphenylene sulfide resin layers including a first polyphenylene sulfide resin layer and a second polyphenylene sulfide resin layer.

During the above co-extrusion, the stacking order of the resin layers and the thickness of each layer can be appropriately adjusted to implement the properties desired in the invention.

According to the above implementation example, when the co-extruded polyphenylene sulfide resin layer of two or more layers is included, it can be advantageous in terms of functionality in that the physical properties of the film, such as stretchability, strength and elongation, can be controlled, and in terms of economic efficiency of the product.

Specifically, referring to FIG. 2, the biaxially stretched polyphenylene sulfide film (1) may include two coextruded polyphenylene sulfide resin layers including a first polyphenylene sulfide resin layer (11) and a second polyphenylene sulfide resin layer (12).

At this time, the first polyphenylene sulfide resin layer may include the first polyphenylene sulfide resin, the specific type and properties of which are as described above.

In addition, the second polyphenylene sulfide resin layer may include the second polyphenylene sulfide resin, the specific type and properties of which are as described above.

According to an embodiment, the thickness ratio of the first polyphenylene sulfide resin layer and the second polyphenylene sulfide resin layer may be 1:9 to 5:5, 1:9 to 4:6, 1:9 to 3:7, 1.5:8.5 to 4:6, 2:8 to 4:6, 2:8 to 3:7, 1.5:8.5 to 3:7, or 1.5:8.5 to 2.5:7.5. When the thickness ratio in the above range is satisfied, it may be more advantageous in implementing the desired effect.

In addition, referring to FIG. 3, the biaxially stretched polyphenylene sulfide film (1) may include three coextruded polyphenylene sulfide resin layers including a first polyphenylene sulfide resin layer (11), a second polyphenylene sulfide resin layer (12), and a third polyphenylene sulfide resin layer (13).

At this time, the first polyphenylene sulfide resin layer may include the first polyphenylene sulfide resin, the specific type and properties of which are as described above.

In addition, the second polyphenylene sulfide resin layer may include a second polyphenylene sulfide resin, the specific type and properties of which are as described above.

In addition, the third polyphenylene sulfide resin layer may include a third polyphenylene sulfide resin, and the specific type and properties of the third polyphenylene sulfide resin may be identical to or similar to the type and properties of the first polyphenylene sulfide resin.

Specifically, the biaxially oriented polyphenylene sulfide film includes three coextruded polyphenylene sulfide resin layers including a first polyphenylene sulfide resin layer, a second polyphenylene sulfide resin layer, and a third polyphenylene sulfide resin layer, wherein the first polyphenylene sulfide resin layer includes a first polyphenylene sulfide resin having a linearity of 0.710 or more to 0.770 or less, the second polyphenylene sulfide resin layer includes a second polyphenylene sulfide resin having a linearity of 0.680 or more to less than 0.710, and the third polyphenylene sulfide resin layer may include a third polyphenylene sulfide resin having a linearity of 0.710 or more to 0.770 or less.

In addition, when the biaxially stretched polyphenylene sulfide film includes the three coextruded polyphenylene sulfide resin layers, the overall average linearity (TL) of the polyphenylene sulfide resin layers including the first polyphenylene sulfide resin layer, the second polyphenylene sulfide resin layer, and the third polyphenylene sulfide resin layer may be 0.689 or more, 0.690 or more, 0.691 or more, 0.692 or more, 0.693 or more, 0.694 or more, 0.695 or more, 0.696 or more, 0.698 or more, 0.700 or more, 0.710 or more, 0.715 or more, or 0.720 or more. The overall average linearity (TL) of the polyphenylene sulfide resin layer may be 0.750 or less, 0.740 or less, 0.730 or less, 0.725 or less, 0.724 or less, 0.723 or less, or 0.722 or less. Specifically, the overall average linearity (TL) of the polyphenylene sulfide resin layer may be 0.689 to 0.750, 0.689 to 0.740, 0.689 to 0.730, 0.689 to 0.725, 0.689 to 0.721, 0.689 to 0.720, 0.689 to 0.710, 0.690 to 0.710, 0.692 to 0.710, 0.693 to 0.705, 0.695 to 0.705, or 0.695 to 0.700.

The thickness ratio of the first polyphenylene sulfide resin layer, the second polyphenylene sulfide resin layer, and the third polyphenylene sulfide resin layer may be, for example, 0.5:9:0.5 to 2.5:5:2.5, 0.5:9:0.5 to 2:6:2, 0.7:8.6:0.7 to 2:6:2, or 0.7:8.6:0.7 to 1.5:7:1.5. When the thickness ratio in the above range is satisfied, it may be more advantageous in implementing the desired effect.

The thickness of the first polyphenylene sulfide resin layer may be, for example, 1 ㎛ to 40 ㎛, 1 ㎛ to 30 ㎛, or 2.5 ㎛ to 20 ㎛.

The thickness of the second polyphenylene sulfide resin layer may be, for example, 10 µm to 90 µm, 10 µm to 75 µm, or 10 µm to 60 µm.

The thickness of the third polyphenylene sulfide resin layer may be, for example, 1 ㎛ to 40 ㎛, 1 ㎛ to 30 ㎛, or 2.5 ㎛ to 20 ㎛.

The above biaxially stretched polyphenylene sulfide film may have a thickness of, for example, 10 µm to 150 µm, 10 µm to 100 µm, 10 µm to 80 µm, or 10 µm to 60 µm.

Meanwhile, a biaxially stretched polyphenylene sulfide film according to one embodiment may further include a resin layer other than the polyphenylene sulfide resin layer and the polyphenylene sulfide resin layer.

Specifically, the biaxially stretched polyphenylene sulfide film may be a coextruded film including the polyphenylene sulfide resin layer and one or more resin layers other than the polyphenylene sulfide resin layer.

For example, the biaxially oriented polyphenylene sulfide film may further include a polyester resin layer, a polyimide resin layer, or both.

Specifically, the biaxially stretched polyphenylene sulfide film may be a coextruded film including the polyphenylene sulfide resin layer and the polyester resin layer.

Alternatively, the biaxially stretched polyphenylene sulfide film may be a coextruded film including the polyphenylene sulfide resin layer and the polyimide resin layer.

Alternatively, the biaxially stretched polyphenylene sulfide film may be a coextruded film including the polyphenylene sulfide resin layer, the polyester resin layer, and the polyimide resin layer.

Each resin included in the above polyester resin layer and the above polyimide resin layer may include a commonly used polyester-based resin and polyimide-based resin.

During the above co-extrusion, the stacking order of the resin layers and the thickness of each layer can be appropriately adjusted to implement the properties desired in the invention.

In addition, according to an embodiment, the biaxially oriented polyphenylene sulfide film may include various additives to efficiently achieve its purpose and desired effect.

The above additives may include, but are not limited to, wear resistance improvers such as silica powder, molybdenum disulfide, and fluorine resin; reinforcing agents such as glass fiber; flame retardancy improvers such as antimony trioxide, magnesium carbonate, and calcium carbonate; electrical property improvers such as clay and mica; tracking resistance improvers such as asbestos and silica; acid resistance enhancers such as barium sulfate, silica, and calcium metasilicate; thermal conductivity improvers such as iron powder, zinc powder, aluminum powder, and copper powder; colorants such as glass beads, talc, diatomaceous earth, alumina, or hydrated alumina metal oxide; and release agents.

Properties of biaxially stretched polyphenylene sulfide film

The biaxially oriented polyphenylene sulfide film according to the embodiment can simultaneously improve electrical properties such as low permittivity and dielectric loss, mechanical properties such as excellent tensile strength, elongation, and modulus, and thermal properties such as low thermal shrinkage rate and thermal expansion coefficient due to the above characteristics, and therefore can be usefully utilized in metal-clad laminates, such as flexible copper clad laminates (FCCL), and in particular, has great advantages such as being utilized for high-frequency applications of 5G.

<Electrical properties>

The biaxially oriented polyphenylene sulfide film according to the embodiment may have a dielectric constant (P ₁₀ ) of 3.50 Dk or less at a frequency of 10 GHz.

Specifically, the biaxially oriented polyphenylene sulfide film may have a permittivity (P ₁₀ ) at a frequency of 10 GHz of 3.45 Dk or less, 3.42 Dk or less, 3.40 Dk or less, less than 3.40 Dk, 3.39 Dk or less, 3.38 Dk or less, 3.37 Dk or less, 3.36 Dk or less, 3.35 Dk or less, 3.34 Dk or less, 3.33 Dk or less, or 3.32 Dk or less. In addition, the biaxially oriented polyphenylene sulfide film may have a permittivity (P ₁₀ ) at a frequency of 10 GHz of 2.80 Dk or more, 2.90 Dk or more, 3.00 Dk or more, 3.10 Dk or more, or 3.20 Dk or more.

In addition, the biaxially stretched polyphenylene sulfide film according to the embodiment may have a dielectric loss (D ₁₀ ) of 0.004 Df or less at a frequency of 10 GHz.

Specifically, the biaxially oriented polyphenylene sulfide film may have a dielectric loss (D ₁₀ ) at a frequency of 10 GHz of less than 0.0040 Df, less than or equal to 0.0039 Df, less than or equal to 0.0038 Df, less than or equal to 0.0035 Df, less than or equal to 0.0033 Df, less than or equal to 0.0032 Df, less than or equal to 0.0030 Df, less than or equal to 0.0025 Df, less than or equal to 0.0023 Df, less than or equal to 0.0020 Df, or less than 0.0020 Df. In addition, the biaxially oriented polyphenylene sulfide film may have a dielectric loss (D ₁₀ ) at a frequency of 10 GHz of 0.0010 Df or more, 0.0012 Df or more, 0.0015 Df or more, or 0.0016 Df or more.

In addition, the biaxially stretched polyphenylene sulfide film according to the embodiment may have a dielectric constant (P ₂₈ ) of 3.50 Dk or less at a frequency of 28 GHz.

Specifically, the biaxially oriented polyphenylene sulfide film may have a permittivity (P ₂₈ ) at a frequency of 28 GHz of 3.45 Dk or less, 3.43 Dk or less, 3.42 Dk or less, less than 3.41 Dk, 3.40 Dk or less, 3.39 Dk or less, 3.38 Dk or less, 3.37 Dk or less, 3.36 Dk or less, 3.35 Dk or less, 3.34 Dk or less, 3.33 Dk or less, or 3.32 Dk or less. In addition, the biaxially oriented polyphenylene sulfide film may have a permittivity (P ₂₈ ) at a frequency of 28 GHz of 2.80 Dk or more, 2.90 Dk or more, 3.00 Dk or more, 3.10 Dk or more, or 3.20 Dk or more.

In addition, the biaxially stretched polyphenylene sulfide film according to the embodiment may have a dielectric loss (D ₂₈ ) of 0.004 Df or less at a frequency of 28 GHz.

Specifically, the biaxially oriented polyphenylene sulfide film may have a dielectric loss ( _D28 ) at a frequency of 28 GHz of less than 0.0040 Df, less than or equal to 0.0039 Df, less than or equal to 0.0038 Df, less than or equal to 0.0035 Df, less than or equal to 0.0033 Df, less than or equal to 0.0032 Df, less than or equal to 0.0030 Df, less than or equal to 0.0025 Df, less than or equal to 0.0023 Df, less than or equal to 0.0020 Df, or less than or equal to 0.0020 Df. In addition, the biaxially stretched polyphenylene sulfide film may have a dielectric loss ( _D28 ) at a frequency of 28 GHz of 0.0010 Df or more, 0.0012 Df or more, 0.0015 Df or more, 0.0016 Df or more, or 0.0020 Df or more.

In addition, the biaxially oriented polyphenylene sulfide film according to the embodiment may have a dielectric constant at a frequency of 10 GHz as P ₁₀ and a dielectric constant at a frequency of 28 GHz as P ₂₈ , where the sum of P ₁₀ and P ₂₈ (P ₁₀ + P ₂₈ ) may be 6.85 Dk or less.

Specifically, the sum of P ₁₀ and P ₂₈ (P ₁₀ +P ₂₈ ) may be 6.85 Dk or less, 6.84 Dk or less, 6.83 Dk or less, 6.82 Dk or less, 6.81 Dk or less, 6.80 Dk or less, 6.79 Dk or less, or 6.78 Dk or less. In addition, the sum of P ₁₀ and P ₂₈ (P ₁₀ +P ₂₈ ) may be 6.30 Dk or more, 6.35 Dk or more, 6.40 Dk or more, 6.45 Dk or more, 6.48 Dk or more, 6.50 Dk or more, 6.52 Dk or more, 6.55 Dk or more, or 6.58 Dk or more.

In addition, in the biaxially oriented polyphenylene sulfide film according to the embodiment, when the dielectric loss at a frequency of 10 GHz is D ₁₀ and the dielectric loss at a frequency of 28 GHz is D ₂₈ , the sum of D ₁₀ and D ₂₈ (D ₁₀ + D ₂₈ ) may be less than 0.0070 Df.

Specifically, the sum of D ₁₀ and D ₂₈ (D ₁₀ + D ₂₈ ) may be less than 0.0070 Df, less than or equal to 0.0065 Df, less than or equal to 0.0064 Df, less than or equal to 0.0063 Df, or less than or equal to 0.0060 Df. In addition, the sum of D ₁₀ and D ₂₈ (D ₁₀ + D ₂₈ ) may be greater than or equal to 0.0020 Df, greater than or equal to 0.0025 Df, greater than or equal to 0.0030 Df, greater than or equal to 0.0035 Df, greater than or equal to 0.0040 Df, or greater than or equal to 0.0045 Df.

In this specification, the permittivity and dielectric loss were measured using a network analyzer, MS46122B-043 from ANRITSUZ (Japan), and a cavity resonator for 10 GHz and 28 GHz from AET (Japan), respectively. The permittivity and dielectric loss are values calculated by recording the average values of five measurements of a 50 mm x 50 mm biaxially oriented polyphenylene sulfide film specimen in an environment of 23°C/50% RH. At this time, the biaxially oriented polyphenylene sulfide film specimen was pre-dried at 120°C for 24 hours.

<Mechanical properties>

The biaxially oriented polyphenylene sulfide film according to the embodiment may have a tensile strength of 10 kgf/mm2 or more, 15 kgf/mm2 or more, 18 kgf/mm2 or more, or 20 kgf/mm2 or more, and may be 40 kgf/mm2 or less, 35 kgf/mm2 or less, 30 kgf/mm2 or less, or 25 kgf/mm2 or less. Specifically, the biaxially oriented polyphenylene sulfide film may have a tensile strength of 10 kgf/mm2 to 30 kgf/mm2, 12 kgf/mm2 to 30 kgf/mm2, 15 kgf/mm2 to 30 kgf/mm2, or 18 kgf/mm2 to 30 kgf/mm2.

In addition, the biaxially oriented polyphenylene sulfide film may have a tensile strength (TS MD) in the longitudinal direction ( _MD ) of 19 kgf/mm2 to 25 kgf/mm2, 19 kgf/mm2 to 24 kgf/mm2, or 19 kgf/mm2 to 23 kgf/mm2.

In addition, the biaxially oriented polyphenylene sulfide film may have a tensile strength (TS _TD ) in the transverse direction (TD) of 10 kgf/mm2 to 30 kgf/mm2, 10 kgf/mm2 to 28 kgf/mm2, 10 kgf/mm2 to 26 kgf/mm2, or 10 kgf/mm2 to 25 kgf/mm2.

Additionally, the biaxially oriented polyphenylene sulfide film may have an elongation of 40% or more, 45% or more, 50% or more, or 60% or more. Specifically, the biaxially oriented polyphenylene sulfide film may have an elongation of 40% to 90%, 50% to 90%, or 55% to 90%.

Additionally, the biaxially oriented polyphenylene sulfide film may have an elongation (E _MD ) in the machine direction (MD) of 66% to 90%, 70% to 90%, or 75% to 90%.

Additionally, the biaxially oriented polyphenylene sulfide film may have an elongation (E _TD ) in the transverse direction (TD) of 50% to 90%, 55% to 90%, or 56% to 80%.

In addition, the biaxially oriented polyphenylene sulfide film may have a modulus of 320 kgf/mm2 or more, 330 kgf/mm2 or more, 340 kgf/mm2 or more, 350 kgf/mm2 or more, 360 kg/mm2 or more, 365 kg/mm2 or more, 368 kg/mm2 or more, 370 kg/mm2 or more, 372 kg/mm2 or more, 375 kg/mm2 or more, or 378 kg/mm2 or more, and may be 500 kg/mm2 or less, 450 kg/mm2 or less, 400 kg/mm2 or less, or less than 400 kg/mm2.

Specifically, the biaxially oriented polyphenylene sulfide film may have a modulus (M _MD ) in the machine direction (MD) of 320 kgf/mm2 to 450 kgf/mm2, 350 kgf/mm2 to 450 kgf/mm2, 360 kgf/mm2 to 450 kgf/mm2, 365 kgf/mm2 to 450 kgf/mm2, 370 kgf/mm2 to 450 kgf/mm2, 375 kgf/mm2 to 450 kgf/mm2, 380 kgf/mm2 to 430 kgf/mm2, or 380 kgf/mm2 to 420 kgf/mm2.

The above biaxially oriented polyphenylene sulfide film may have a modulus (M _TD ) in the transverse direction (TD) of 350 kgf/mm2 to 450 kgf/mm2, 350 kgf/mm2 to 420 kgf/mm2, 360 kgf/mm2 to 400 kgf/mm2, or 360 kgf/mm2 to 390 kgf/mm2.

The tensile strength, elongation, and modulus of the biaxially oriented polyphenylene sulfide film are measured by cutting a biaxially oriented polyphenylene sulfide film specimen to 100 mm in length and 15 mm in width according to ASTM D882, mounting it so that the chuck length is 50 mm, and conducting an experiment at room temperature of 25℃ at a tensile speed of 200 mm/min using a universal testing machine (UTM, model number 5566A) from INSTRON, and then measuring them using a program built into the equipment.

<Thermal properties>

The biaxially oriented polyphenylene sulfide film according to the embodiment may have a coefficient of thermal expansion (CTE _MD ) in the longitudinal direction (MD) in the range of -80 ppm/℃ to -50 ppm/℃ in the range of 30°C to 200°C.

Specifically, the biaxially oriented polyphenylene sulfide film may have a coefficient of thermal expansion (CTE _MD ) in the longitudinal direction (MD) at a temperature ranging from 30°C to 200°C of -78 ppm/°C to -50 ppm/°C, -75 ppm/°C to -55 ppm/°C, -75 ppm/°C to -60 ppm/°C, or -70 ppm/°C to -60 ppm/°C.

In addition, the biaxially oriented polyphenylene sulfide film according to the embodiment may have a coefficient of thermal expansion (CTE _TD ) in the transverse direction (TD) in the range of 30°C to 200°C of 10 ppm/°C to 80 ppm/°C.

Specifically, the biaxially oriented polyphenylene sulfide film has a coefficient of thermal expansion (CTE _TD ) in the transverse direction (TD) at a temperature range of 30°C to 200°C of 10 ppm/°C to 70 ppm/°C, 10 ppm/°C to 65 ppm/°C, 15 ppm/°C to 65 ppm/°C, 16 ppm/°C to 80 ppm/°C, 16 ppm/°C to 70 ppm/°C, 16 ppm/°C to 62 ppm/°C, 20 ppm/°C to 80 ppm/°C, 20 ppm/°C to 70 ppm/°C, 30 ppm/°C to 80 ppm/°C, 30 ppm/°C to 70 ppm/°C, 40 ppm/°C to 80 ppm/°C, 40 ppm/°C to 70 ppm/°C, 50 It can be from 50 ppm/℃ to 80 ppm/℃, from 50 ppm/℃ to 70 ppm/℃, from 52 ppm/℃ to 70 ppm/℃, from 52 ppm/℃ to 60 ppm/℃, from 60 ppm/℃ to 70 ppm/℃, from 10 ppm/℃ to 40 ppm/℃, from 10 ppm/℃ to 30 ppm/℃, or from 10 ppm/℃ to 20 ppm/℃.

The above biaxially oriented polyphenylene sulfide film can have a coefficient of thermal expansion (CTE _MD ) in the longitudinal direction (MD) and a coefficient of thermal expansion (CTE _TD ) in the transverse direction (TD) in the range from 30°C to 200°C, which can be affected by the thermal expansion rate of the polyphenylene sulfide resin itself and the thermal expansion rate according to the process, and when the coefficient of thermal expansion (CTE _MD ) in the longitudinal direction (MD) and the coefficient of thermal expansion (CTE _TD ) in the transverse direction (TD) in the range from 30°C to 200°C each satisfy the above range, high heat resistance can be realized and heat shrinkage at high temperatures can be minimized.

In addition, the biaxially oriented polyphenylene sulfide film according to the embodiment may have a coefficient of thermal expansion (CTE _MD ) in the longitudinal direction (MD) in the range of 30°C to 80°C of 10 ppm/°C to 50 ppm/°C.

Specifically, the biaxially oriented polyphenylene sulfide film may have a coefficient of thermal expansion (CTE _MD ) in the longitudinal direction (MD) at a temperature ranging from 30°C to 80°C of 15 ppm/°C to 50 ppm/°C, 20 ppm/°C to 50 ppm/°C, 20 ppm/°C to 45 ppm/°C, or 30 ppm/°C to 40 ppm/°C.

In addition, the biaxially oriented polyphenylene sulfide film according to the embodiment may have a coefficient of thermal expansion (CTE _TD ) in the transverse direction (TD) in the range of 30°C to 80°C of 10 ppm/°C to 50 ppm/°C.

Specifically, the biaxially oriented polyphenylene sulfide film may have a coefficient of thermal expansion (CTE _TD ) in the transverse direction (TD) at a temperature ranging from 30°C to 80°C of 15 ppm/°C to 50 ppm/°C, 20 ppm/°C to 50 ppm/°C, 20 ppm/°C to 45 ppm/°C, 20 ppm/°C to 40 ppm/°C, 25 ppm/°C to 40 ppm/°C, or 25 ppm/°C to 35 ppm/°C.

The coefficient of thermal expansion (CTE _MD ) in the longitudinal direction (MD) and the coefficient of thermal expansion (CTE _TD ) in the transverse direction (TD) of the biaxially oriented polyphenylene sulfide film in the temperature range from 30°C to 80°C can be affected by the thermal expansion rate of the polyphenylene sulfide resin itself, and when the coefficient of thermal expansion (CTE _MD ) in the longitudinal direction (MD) and the coefficient of thermal expansion (CTE _TD ) in the transverse direction (TD) in the temperature range from 30°C to 80°C each satisfy the above range, high heat resistance can be realized.

The coefficient of thermal expansion (CTE) of the above biaxially oriented polyphenylene sulfide film was measured using TMA Q-200 of TA (USA) at a heating rate of 10 ℃/min from 30 ℃ to 200 ℃ for the biaxially oriented polyphenylene sulfide films manufactured in the examples and comparative examples, and the CTEs in the 30 to 80 ℃ section and the 30 to 200 ℃ section were calculated, respectively.

In addition, the biaxially stretched polyphenylene sulfide film according to the embodiment may have a heat shrinkage rate (S ₁₅₀ ) expressed by the following Equation 4-1 of 2.0 or less.

[Formula 4-1] Heat shrinkage rate (S ₁₅₀ ) = × 100(%)

In the above equation 4-1,

L ₂₅ is the initial length of the biaxially stretched polyphenylene sulfide film specimen at 25°C,

L ₁₅₀ is the length of a biaxially stretched polyphenylene sulfide film specimen after staying in a hot air blower at 150℃ for 30 minutes.

The heat shrinkage rate (S ₁₅₀ ) expressed by the above formula 4-1 is a value converted into a percentage of the degree of heat shrinkage of the biaxially oriented polyphenylene sulfide film specimen at a hot air temperature of 150°C, and is a value calculated as a percentage of the initial length of the biaxially oriented polyphenylene sulfide film specimen and the change in length of the biaxially oriented polyphenylene sulfide film specimen measured immediately after remaining in a hot air blower at 150°C for 30 minutes.

The above heat shrinkage rate (S ₁₅₀ ) can be calculated by cutting the biaxially stretched polyphenylene sulfide film into a specimen of 200 mm in length and 15 mm in width regardless of the direction, and then measuring the initial length at room temperature and the length of the biaxially stretched polyphenylene sulfide film specimen after remaining in a hot air oven at 150° C. for 30 minutes.

Specifically, the biaxially stretched polyphenylene sulfide film may have a heat shrinkage ratio (S ₁₅₀ ) expressed by the above formula 4-1 of 2.0 or less, 1.8 or less, 1.7 or less, 1.5 or less, 1.2 or less, 1.0 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less, or 0.3 or less.

In addition, the biaxially stretched polyphenylene sulfide film according to the embodiment may have a heat shrinkage ratio (S _MD150 ) in the longitudinal direction (MD) represented by the above formula 4-1 of 2.0 or less, 1.8 or less, 1.7 or less, 1.5 or less, or 1.2 or less.

In addition, the biaxially stretched polyphenylene sulfide film according to the embodiment may have a heat shrinkage ratio (S _TD150 ) in the transverse direction (TD) represented by the above formula 4-1 of 2.0 or less, 1.8 or less, 1.7 or less, 1.5 or less, 1.2 or less, 1.0 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less, or 0.3 or less.

In addition, the biaxially stretched polyphenylene sulfide film according to the embodiment may have a heat shrinkage rate (S ₁₉₀ ) expressed by the following Equation 4-2 of 5.0 or less.

[Formula 4-2] Heat shrinkage rate (S ₁₉₀ ) = × 100

In the above equation 4-2,

L ₂₅ is the initial length of the biaxially stretched polyphenylene sulfide film specimen at 25°C,

L ₁₉₀ is the length of a biaxially oriented polyphenylene sulfide film specimen after being stored in a hot air blower at 190°C for 30 minutes.

Specifically, the biaxially stretched polyphenylene sulfide film may have a heat shrinkage ratio (S ₁₉₀ ) expressed by the above formula 4-2 of 5.0 or less, 4.0 or less, 3.0 or less, less than 3.0, 2.9 or less, 2.6 or less, 2.5 or less, 2.3 or less, 2.2 or less, 2.0 or less, 1.8 or less, 1.7 or less, or 1.5 or less.

In addition, the biaxially stretched polyphenylene sulfide film according to the embodiment may have a heat shrinkage ratio (S _MD190 ) in the longitudinal direction (MD) represented by the above formula 4-2 of 3.0 or less, less than 3.0, 2.9 or less, 2.6 or less, 2.5 or less, 2.3 or less, 2.2 or less, 2.0 or less, 1.8 or less, or 1.7 or less.

In addition, the biaxially stretched polyphenylene sulfide film according to the embodiment may have a heat shrinkage ratio (S _TD190 ) in the transverse direction (TD) represented by the above formula 4-2 of 4.0 or less, 3.5 or less, 3.0 or less, less than 3.0, 2.9 or less, 2.6 or less, 2.5 or less, 2.3 or less, 2.2 or less, 2.0 or less, 1.9 or less, 1.8 or less, 1.7 or less, or 1.5 or less.

When the heat shrinkage rate of the above biaxially stretched polyphenylene sulfide film satisfies the above range, the heat resistance is excellent, so that processability and productivity can be improved, and high-quality films and molded articles can be realized.

Meanwhile, the biaxially oriented polyphenylene sulfide film having a thickness of 25 ㎛ may have a crystallinity of 40 to 60%, 43 to 58%, 46 to 56%, or 46 to less than 56% as measured by X-ray diffraction analysis, and a crystallite size of 40 to 80 Å, 50 to 75 Å, or 60 to 70 Å.

The above crystallinity and crystallite size were measured using X-ray diffraction analysis (Rigaku Ultima IV).

Specifically, the X-ray source used CuK _α radiation filtered through a K _β filter. The X-ray generator operated a rotating anode generator under the conditions of 45 kev and 200 mA. The crystallinity of the film can be calculated by a program built into the equipment using the Pearson VII function and the crystallite size can be calculated by the pseudo-Voigt. function at the peak of 2θ = 20.6 ^o .

When the above biaxially stretched polyphenylene sulfide film satisfies the crystallinity and crystallite size within the above ranges, heat setting at high temperatures is possible, stretching is performed well, and formability is excellent.

[Method for manufacturing biaxially oriented polyphenylene sulfide film]

In one embodiment, a method for producing a biaxially oriented polyphenylene sulfide film is provided, comprising: a first step of melt-extruding a polyphenylene sulfide resin to produce a sheet; and a second step of biaxially oriented the sheet in the longitudinal and transverse directions and heat-setting the sheet, wherein the polyphenylene sulfide resin layer includes the polyphenylene sulfide resin, and the polyphenylene sulfide resin layer has an overall average linearity (TL) of 0.689 or more, a dielectric constant at a frequency of 10 GHz of 3.50 Dk or less, a coefficient of thermal expansion (CTE) of 20 ppm/°C to 50 ppm/°C in the range of 30°C to 80°C, and a modulus of 360 kg/mm2 or more.

The method for manufacturing the biaxially oriented polyphenylene sulfide film according to the embodiment is an economical and efficient method, and can provide a polyphenylene sulfide film capable of implementing the above characteristics, and further improve processability and productivity.

Specifically, referring to FIG. 4, the method (S100) for manufacturing the biaxially stretched polyphenylene sulfide film includes a first step (S110) of manufacturing a sheet by melt-extruding polyphenylene sulfide resin.

The above polyphenylene sulfide resin may be a first polyphenylene sulfide resin, a second polyphenylene sulfide resin, or a mixture thereof. The types and properties of the first polyphenylene sulfide resin and the second polyphenylene sulfide resin, and the properties of the mixed resin are as described above.

Specifically, the polyphenylene sulfide resin may include a mixed resin of a first polyphenylene sulfide resin and a second polyphenylene sulfide resin.

In the first step, the melt extrusion can be performed at a temperature of 300°C to 340°C.

When the above melt extrusion is performed within the above range, the desired properties can be achieved in an economical and efficient manner, and processability and productivity can be further improved.

Specifically, the polyphenylene sulfide resin can be melt-extruded to obtain a single-layer amorphous sheet.

For example, a mixed resin of the first polyphenylene sulfide resin and the second polyphenylene sulfide resin can be melt-extruded at 300°C to 340°C.

After the above melt extrusion, a step of pressing the amorphous sheet against a cooling roll cooled to about 10°C to 40°C may be further included.

In addition, the method for manufacturing the biaxially stretched polyphenylene sulfide film (S100) includes a second step (S120) of biaxially stretching the sheet in the longitudinal and transverse directions and heat-setting it.

Specifically, the sheet can be biaxially stretched, and the biaxial stretching step can include, for example, a step of stretching in the machine direction (MD) by 2.5 to 4.5 times, 2.5 to 3.5 times, or 3.0 to 4.0 times at 80°C to 120°C, and a step of stretching in the transverse direction (TD) by 2.5 to 4.5 times, 2.5 to 3.8 times, 3.0 to 4.0 times, or 3.0 to 3.8 times at 85°C to 140°C.

By performing biaxial stretching of the above sheet in both directions, the properties of the biaxially stretched polyphenylene sulfide film can be further improved.

If uniaxial stretching is performed in only one of the longitudinal and transverse directions, the thickness deviation of the biaxially stretched polyphenylene sulfide film may be severe, the strength of the side on which stretching is not performed may decrease, and the thermal properties may also deteriorate.

Additionally, the heat fixation step can be performed at 200°C to 260°C, or at 200°C to 255°C.

Meanwhile, according to another embodiment, with reference to FIG. 5, the method (S100') for manufacturing the biaxially oriented polyphenylene sulfide film may include a first step (S110') of manufacturing a laminated sheet of two or more layers by melt coextrusion using two or more kinds of polyphenylene sulfide resins, and a second step (S120') of biaxially oriented the laminated sheet in the longitudinal and transverse directions and heat-setting it.

Specifically, the first polyphenylene sulfide resin and the second polyphenylene sulfide resin can be melt co-extruded.

Additionally, the first polyphenylene sulfide resin, the second polyphenylene sulfide resin, and the third polyphenylene sulfide resin can be melt co-extruded.

The types and properties of the first polyphenylene sulfide resin, the second polyphenylene sulfide resin, and the third polyphenylene sulfide resin are as described above, respectively.

For example, the linearity of the first polyphenylene sulfide resin may be 0.710 or more and 0.770 or less, the linearity of the second polyphenylene sulfide resin may be 0.680 or more and less than 0.710, and the linearity of the third polyphenylene sulfide resin may be 0.710 or more and 0.770 or less.

According to one embodiment, the temperature during the molten co-extrusion may be, for example, 300°C to 340°C.

In another embodiment, during the molten co-extrusion, the extrusion temperatures of the first polyphenylene sulfide resin, the second polyphenylene sulfide resin, and the third polyphenylene sulfide resin can each be controlled.

Specifically, the extrusion temperatures of the first polyphenylene sulfide resin, the second polyphenylene sulfide resin, and the third polyphenylene sulfide resin may be the same or different from each other.

For example, the extrusion temperature of the first polyphenylene sulfide resin may be, for example, 300°C to 340°C, the extrusion temperature of the second resin may be, for example, 300°C to 340°C, and the extrusion temperature of the third resin may be, for example, 300°C to 340°C.

The second step (S120') of biaxially stretching and heat-setting the laminated sheet in the longitudinal and transverse directions can be performed in the same manner as S120 described above.

The method for manufacturing the biaxially oriented polyphenylene sulfide film according to the embodiment is an economical and efficient method, and can provide a biaxially oriented polyphenylene sulfide film capable of implementing the above characteristics, and further improve processability and productivity.

Uses of biaxially oriented polyphenylene sulfide films

According to an embodiment, the biaxially oriented polyphenylene sulfide film can be usefully applied to a metal-clad laminate.

For example, the biaxially stretched polyphenylene sulfide film layer can be laminated on a metal foil to form a metal foil laminated plate.

In the above metal foil laminated plate, the metal foil may be aluminum foil, copper foil, stainless steel foil, or the like.

According to an embodiment, a flexible copper clad laminate (FCCL) including the biaxially oriented polyphenylene sulfide film can be provided.

The above metal-clad laminate can be manufactured using (1) a coating method (also called a casting method), (2) a pressing method (also called a lamination method), and (3) a sputtering method.

For example, the coating method may include a step of coating the biaxially stretched polyphenylene sulfide film on one side of the copper foil and drying it to remove the solvent.

The above-mentioned pressing method may be a method in which the biaxially stretched polyphenylene sulfide film is coated on one or both sides with, for example, a prepolymer (polyamic acid, PAA) of a thermoplastic PI resin having excellent adhesive properties, dried and imidized to form a composite film, and then the resin is melted again in a high temperature and high pressure atmosphere and copper foil is pressed to form a one-sided or double-sided product.

In addition, the sputtering method can form a metal by sputtering and depositing it on the biaxially stretched polyphenylene sulfide film.

In particular, the biaxially stretched polyphenylene sulfide film has excellent thermal properties, electrical properties, and mechanical properties, and thus can be usefully used for high-frequency 5G applications.

The above contents are explained in more detail by the following examples. However, the following examples are only for illustrating the present invention, and the scope of the examples is not limited to these examples.

Example

Example 1

Step 1: Step of manufacturing a sheet by melting and extruding polyphenylene sulfide resin

A mixed resin was prepared by mixing a first polyphenylene sulfide resin having a linearity of about 0.739 and a second polyphenylene sulfide resin having a linearity of about 0.686 in a weight ratio of 20:80.

The above mixed resin was melt-extruded at a temperature of 310°C using a single screw extruder equipped with a T-die, and an amorphous sheet having a width of about 600 mm and an average thickness of about 310 μm was obtained using a casting roll set to about 25°C.

Step 2: Step of stretching and heat-fixing the sheet in the longitudinal and transverse directions

The amorphous sheet obtained in the first step was uniaxially stretched about 3.5 times in the longitudinal direction at about 88°C, stretched about 3.6 times in the transverse direction at about 100°C, and then heat-set at about 250°C to obtain a biaxially stretched polyphenylene sulfide film including a polyphenylene sulfide resin layer having a thickness of about 25 μm. At this time, the overall average linearity (TL) of the polyphenylene sulfide resin layer was about 0.697.

Examples 2 to 3

A biaxially stretched polyphenylene sulfide film was manufactured in the same manner as in Example 1, except that the stretching conditions, the thickness of the biaxially stretched film, and the properties of the biaxially stretched film were adjusted, as shown in Table 1 below.

Example 4

As shown in Table 2 below, in the first step of Example 1, a first polyphenylene sulfide resin having a linearity of about 0.739, a second polyphenylene sulfide resin having a linearity of about 0.686, and a third polyphenylene sulfide resin having a linearity of about 0.739 were melt coextruded using two single screw extruders equipped with T-dies to obtain a three-layer laminated sheet, except that the same procedure as in Example 1 was followed to manufacture a biaxially oriented polyphenylene sulfide film. At this time, the extrusion temperature of the first polyphenylene sulfide resin was about 310°C, the extrusion temperature of the second polyphenylene sulfide resin was about 310°C, and the extrusion temperature of the third polyphenylene sulfide resin was about 310°C.

Comparative Example 1

As shown in Table 1 below, a biaxially stretched polyphenylene sulfide film was manufactured in the same manner as in Example 1, except that a second polyphenylene sulfide resin having a linearity of about 0.686 was used alone instead of the mixed resin in the first step of Example 1.

Comparative Example 2

As shown in Table 1 below, a biaxially stretched film was manufactured in the same manner as in Example 1, except that in the first step of Example 1, only a liquid crystal polymer (LCP, manufacturer: Kuraray) was used instead of the mixed resin, and the stretching conditions, the thickness of the biaxially stretched film, and the properties of the biaxially stretched film were controlled.

Comparative Example 3

As shown in Table 1 below, in the first step of Example 1, a polyimide (PI) resin (manufacturer: PI Advanced Materials) was used alone instead of the mixed resin, and the stretching conditions, the thickness of the biaxially stretched film, and the physical properties of the biaxially stretched film were adjusted, and a biaxially stretched film was manufactured in the same manner as in Example 1.

Comparative Example 4

As shown in Table 1 below, in the first step of Example 1, a biaxially stretched film was manufactured in the same manner as in Example 1, except that only polyethylene terephthalate (PET) resin (manufacturer: SKC) was used instead of the mixed resin, and the stretching conditions, the thickness of the biaxially stretched film, and the physical properties of the biaxially stretched film were controlled.

Comparative Example 5

As shown in Table 2 below, a biaxially stretched film was manufactured in the same manner as in Example 4, except that the thickness ratio and stretching ratio of the coextruded resin layer were changed.

Evaluation example

Evaluation Example 1: Linearity

Linearity is a value obtained by measuring the melt viscosity of a polyphenylene sulfide resin at frequencies of 100 rad/s and 400 rad/s at about 330°C using a rheometer and comparing the degree of shear thinning using the ratio of these values, which can be expressed by the following Equation 1.

[Formula 1]

Linearity = (melt viscosity of resin at frequency 400 rad/s) / (melt viscosity of resin at frequency 100 rad/s).

-Analysis device: Rheometer (Rheometrics, equipment name: Rheometrics Dynamic Spectrometer)

-Measurement temperature: 330℃

When the above polyphenylene sulfide resin layer includes one type of polyphenylene sulfide resin, the linearity represented by the above formula 1 may mean the overall average linearity (TL) of the polyphenylene sulfide resin layer.

Meanwhile, when the polyphenylene sulfide resin layer includes a mixed resin of two or more types of polyphenylene sulfide resins, the overall average linearity (TL) of the polyphenylene sulfide resin layer can be expressed by the following Equation 2.

[Formula 2]

In the above equation 2,

The above L _k is the linearity of the individual polyphenylene sulfide resins included in the mixed resin,

The above W _k is the weight ratio of the individual polyphenylene sulfide resin to the total weight of the mixed resin (weight of the individual polyphenylene sulfide resin/total weight of the mixed resin).

Meanwhile, when the polyphenylene sulfide resin layer includes two or more co-extruded polyphenylene sulfide resin layers, the overall average linearity (TL) of the polyphenylene sulfide resin layer (co-extruded polyphenylene sulfide resin layer) can be expressed by the following Equation 3.

[Formula 3]

In the above equation 3,

The above L _k is the linearity of the individual polyphenylene sulfide resin contained in the individual polyphenylene sulfide resin layer,

The above T _k is the thickness ratio of the individual polyphenylene sulfide resin layer to the total thickness of the coextruded polyphenylene sulfide resin layer (thickness of the individual polyphenylene sulfide resin layer/total thickness of the coextruded polyphenylene sulfide resin layer).

Evaluation Example 2: Dielectric constant and dielectric loss

As a network analyzer, MS46122B-043 of ANRITSUZ (Japan) and a cavity resonator for 10 GHz and 28 GHz of AET (Japan) were used for measurements, respectively. The above permittivity and dielectric loss are the average values calculated by measuring a biaxially oriented polyphenylene sulfide film specimen of 50 mm x 50 mm 50 times in an environment of 23°C/50% RH. At this time, the biaxially oriented polyphenylene sulfide film specimen was pre-dried at 120°C for 24 hours.

Evaluation Example 3: Tensile strength, modulus, elongation

The tensile strength, elongation, and modulus of the biaxially oriented polyphenylene sulfide film are measured by cutting a biaxially oriented polyphenylene sulfide film specimen into pieces according to ASTM D882, cutting the film to a length of 100 mm and a width of 15 mm, and mounting the specimen with a chuck length of 50 mm, and then performing an experiment at a room temperature of 25°C at a tensile speed of 200 mm/min using a universal testing machine (UTM, model number 5566A) manufactured by INSTRON. The experiment can then be measured using a program built into the equipment.

For the above tensile strength, elongation, and modulus, the longitudinal (MD) and transverse (TD) directions were measured, respectively.

Evaluation Example 4: Heat Shrinkage

The biaxially oriented polyphenylene sulfide films manufactured in the examples and comparative examples were cut into specimens of 200 mm in length and 15 mm in width regardless of the direction, and the initial length at room temperature and the length of the biaxially oriented polyphenylene sulfide film specimens after 30 minutes in a hot air oven were measured, and the heat shrinkage rate was evaluated by calculating it as in the following equations 4-1 and 4-2:

[Formula 4-1] Heat shrinkage rate (S ₁₅₀ ) = × 100

In the above equation 4-1,

L ₂₅ is the initial length of the biaxially stretched polyphenylene sulfide film specimen at 25°C,

L ₁₅₀ is the length of a biaxially stretched polyphenylene sulfide film specimen after staying in a hot air blower at 150℃ for 30 minutes.

[Formula 4-2] Heat shrinkage rate (S ₁₉₀ ) = × 100

In the above equation 4-2,

L ₂₅ is the initial length of the biaxially stretched polyphenylene sulfide film specimen at 25°C,

L ₁₉₀ is the length of a biaxially oriented polyphenylene sulfide film specimen after being stored in a hot air blower at 190°C for 30 minutes.

Evaluation Example 5: Coefficient of Thermal Expansion (CTE)

Using TMA Q-200 from TA (USA), the biaxially oriented polyphenylene sulfide films manufactured in the examples and comparative examples were measured at a heating rate of 10°C/min from 30°C to 200°C, and the CTEs in the 30 to 80°C and 30 to 200°C sections were calculated, respectively.

Evaluation Example 6: Crystallinity and crystallite size

The crystallinity and crystallite size of the biaxially oriented polyphenylene sulfide films manufactured in the examples and comparative examples were measured using X-ray diffraction analysis (Ultima IV, Rigaku Corporation).

Specifically, the X-ray source used CuK _α radiation filtered through a K _β filter. The X-ray generator drove a rotating anode generator under the conditions of 45 kev and 200 mA. At this time, the tube voltage was 20 to 50 kV, the tube current was 2 to 60 mA, and the measurement range was 2θ = 5 ^o - 40 ^o , with a step size of 0.02 deg. and a scan speed of 5 deg/min.

In addition, the degree of crystallinity of the biaxially oriented polyphenylene sulfide film was calculated using the Pearson VII function, and the crystallite size was calculated using the pseudo-Voigt. function at the peak of 2θ = 20.6 ^o using a program built into the equipment.

The results of the above evaluation examples are summarized in Tables 1 to 3 below.

As can be seen in Tables 1 to 3, the biaxially oriented polyphenylene sulfide film includes a polyphenylene sulfide resin layer having a specific range of overall average linearity (TL), and satisfies the dielectric constant at a frequency of 10 GHz in a specific range of thermal expansion coefficients (CTE) and modulus in the range of 30°C to 80°C, respectively, thereby simultaneously improving thermal properties, electrical properties, and mechanical properties, and also improving processability and productivity.

Specifically, the biaxially oriented polyphenylene sulfide films manufactured in Examples 1 to 3 showed significantly improved mechanical properties such as tensile strength, elongation, and modulus of the film, and provided stretchability suitable for film use due to high melt strength. In particular, the biaxially oriented polyphenylene sulfide films manufactured in Examples 1 to 3 could implement high heat resistance and mechanical properties compared to PET, and lower permittivity and dielectric loss compared to PI.

In contrast, the biaxially oriented polyphenylene sulfide film manufactured in Comparative Example 1 using only the second polyphenylene sulfide resin having a linearity of about 0.686 instead of the mixed resin had a large thickness deviation in the film due to the reduced stretchability, making it difficult to obtain reliable result data. In addition, it was confirmed that the biaxially oriented polyphenylene sulfide film manufactured in Comparative Example 1 had an increased degree of crystallinity and crystallite size, which resulted in a reduced stretchability and deteriorated processability, productivity, and moldability.

Meanwhile, in the case of the film of Comparative Example 2 manufactured using LCP instead of polyphenylene sulfide resin, the dielectric constant and dielectric loss increased and the mechanical properties deteriorated, in the case of the film of Comparative Example 3 manufactured using PI, the dielectric constant and dielectric loss increased overall, and in the case of the film of Comparative Example 4 manufactured using PET, it was confirmed that not only the mechanical properties such as tensile strength and modulus deteriorated, but also the thermal properties (heat resistance) deteriorated and the electrical loss increased.

In addition, when including a three-layer co-extruded polyphenylene sulfide resin layer, the mechanical properties such as tensile strength, elongation, and modulus of the film manufactured in Example 4 were improved compared to the film manufactured in Comparative Example 5, and further, by controlling the thickness ratio of the co-extruded resin layer, excellent electrical properties, mechanical properties, and thermal properties could be achieved simultaneously and economically efficiently.

1: Biaxially stretched polyphenylene sulfide film
10: Polyphenylene sulfide resin layer
11: First polyphenylene sulfide resin layer
12: Second polyphenylene sulfide resin layer
13: Third polyphenylene sulfide resin layer

Claims (15)

Comprising a polyphenylene sulfide resin layer including polyphenylene sulfide resin,
The overall average linearity (TL) of the above polyphenylene sulfide resin layer is 0.689 or more,
The dielectric constant at a frequency of 10 GHz is less than 3.50 Dk,
The coefficient of thermal expansion (CTE) in the range of 30℃ to 80℃ is 20 ppm/℃ to 50 ppm/℃,
A biaxially oriented polyphenylene sulfide film having a modulus of 360 kg/mm2 or more.
In the first paragraph,
The above polyphenylene sulfide resin comprises a mixed resin of a first polyphenylene sulfide resin and a second polyphenylene sulfide resin,
The linearity of the first polyphenylene sulfide resin is 0.710 or more and 0.770 or less,
A biaxially oriented polyphenylene sulfide film, wherein the linearity of the resin of the second polyphenylene sulfide is 0.680 or more and less than 0.710.
In the second paragraph,
A biaxially oriented polyphenylene sulfide film, wherein the weight ratio of the first polyphenylene sulfide resin and the second polyphenylene sulfide resin is 10:90 to 50:50.
In the second paragraph,
When measuring melt viscosity at a frequency of 1.99 rad/s at 330℃,
The melting viscosity of the above mixed resin is 2,000 poise to 4,000 poise,
The melting viscosity of the first polyphenylene sulfide resin is 1,000 poise to 30,000 poise,
A biaxially oriented polyphenylene sulfide film, wherein the melting viscosity of the second polyphenylene sulfide resin is 1,000 poise to 25,000 poise.
In the first paragraph,
The above biaxially oriented polyphenylene sulfide film is a biaxially oriented polyphenylene sulfide film comprising two or more coextruded polyphenylene sulfide resin layers including a first polyphenylene sulfide resin layer and a second polyphenylene sulfide resin layer.
In the first paragraph,
The above biaxially stretched polyphenylene sulfide film comprises three coextruded polyphenylene sulfide resin layers including a first polyphenylene sulfide resin layer, a second polyphenylene sulfide resin layer, and a third polyphenylene sulfide resin layer,
The first polyphenylene sulfide resin layer includes a first polyphenylene sulfide resin having a linearity of 0.710 or more and 0.770 or less,
The second polyphenylene sulfide resin layer includes a second polyphenylene sulfide resin having a linearity of 0.680 or more and less than 0.710,
A biaxially oriented polyphenylene sulfide film, wherein the third polyphenylene sulfide resin layer includes a third polyphenylene sulfide resin having a linearity of 0.710 or more and 0.770 or less.
In paragraph 6,
A biaxially oriented polyphenylene sulfide film, wherein the thickness ratio of the first polyphenylene sulfide resin layer, the second polyphenylene sulfide resin layer, and the third polyphenylene sulfide resin layer is 0.5:9:0.5 to 2.5:5:2.5.
In the first paragraph,
A biaxially oriented polyphenylene sulfide film further comprising a polyester resin layer.
In the first paragraph,
The dielectric constant at a frequency of 10 GHz is P ₁₀ , and the dielectric loss is D ₁₀ .
When the dielectric constant at a frequency of 28 GHz is P ₂₈ and the dielectric loss is D ₂₈ ,
The sum of P ₁₀ and P ₂₈ (P ₁₀ +P ₂₈ ) is less than or equal to 6.85 Dk,
A biaxially oriented polyphenylene sulfide film, wherein the sum of D ₁₀ and D ₂₈ (D ₁₀ + D ₂₈ ) is less than 0.007 Df.
In the first paragraph,
The coefficient of thermal expansion (CTE _MD ) in the longitudinal direction (MD) in the range of 30℃ to 200℃ is -80 ppm/℃ to -50 ppm/℃,
The coefficient of thermal expansion (CTE _TD ) in the transverse direction (TD) at temperatures from 30°C to 200°C is 10 ppm/°C to 80 ppm/°C,
A biaxially stretched polyphenylene sulfide film having a heat shrinkage ratio (S ₁₅₀ ) of 2.0 or less, as expressed by the following formula 4-1:
[Formula 4-1] Heat shrinkage rate (S ₁₅₀ ) = × 100
In the above equation 4-1,
L ₂₅ is the initial length of the biaxially stretched polyphenylene sulfide film specimen at 25°C,
L ₁₅₀ is the length of a biaxially oriented polyphenylene sulfide film specimen after being stored in a hot air blower at 150°C for 30 minutes.
In the first paragraph,
The tensile strength is 10 kgf/mm2 to 30 kgf/mm2,
The believers are 40% to 90%,
The modulus (M MD ) in the longitudinal direction ( _MD ) is 320 kgf/mm2 to 450 kgf/mm2,
A biaxially oriented polyphenylene sulfide film having a modulus (M _TD ) in the transverse direction (TD) of 350 kgf/mm2 to 450 kgf/mm2.
In the first paragraph,
The biaxially oriented polyphenylene sulfide film having a thickness of 25 ㎛ has a crystallinity of 40 to 60% and a crystallite size of 40 to 80 Å as measured by X-ray diffraction analysis.
A first step of manufacturing a sheet by melting and extruding polyphenylene sulfide resin; and
A second step of stretching and heat-fixing the above sheet in the longitudinal and transverse directions is included.
Comprising a polyphenylene sulfide resin layer including the above polyphenylene sulfide resin,
The overall average linearity (TL) of the above polyphenylene sulfide resin layer is 0.689 or more,
The dielectric constant at a frequency of 10 GHz is less than or equal to 3.50 Dk,
The coefficient of thermal expansion (CTE) in the range of 30℃ to 80℃ is 20 ppm/℃ to 50 ppm/℃,
A method for manufacturing a biaxially oriented polyphenylene sulfide film having a modulus of 360 kg/mm2 or more.
In Article 13,
The above melt extrusion is performed at a temperature of 300°C to 340°C,
The above biaxial stretching is performed by stretching 2.5 to 4.5 times in the longitudinal direction at 80°C to 120°C and by stretching 2.5 to 4.5 times in the transverse direction at 85 to 140°C.
A method for manufacturing a biaxially stretched polyester film, wherein the above heat fixation is performed at 200°C to 260°C.
In Article 13,
The above melt extrusion is,
A mixed resin of the first polyphenylene sulfide resin and the second polyphenylene sulfide resin is melt-extruded, or
It is performed by melt co-extruding a first polyphenylene sulfide resin, a second polyphenylene sulfide resin, and a third polyphenylene sulfide resin,
The linearity of the first polyphenylene sulfide resin is 0.710 or more and 0.770 or less,
The linearity of the second polyphenylene sulfide resin is 0.680 or more and less than 0.710,
A method for manufacturing a biaxially oriented polyester film, wherein the linearity of the third polyphenylene sulfide resin is 0.710 or more and 0.770 or less.

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