Liquid crystal (LC) composition with extremely-low dielectric loss and high-frequency component including same

Abstract

Disclosed are a liquid crystal (LC) composition and a high-frequency component including the same. The LC composition includes one or more selected from compounds shown in structural formula (I) and one or more selected from compounds shown in structural formula (II): ##STR00001## where R.sub.1 is selected from alkyl with 1 to 10 carbon atoms, alkenyl with 2 to 10 carbon atoms, fluorinated alkyl, fluorinated alkenyl, and cycloalkyl; one of X.sub.1, X.sub.2, and X.sub.3 is methyl or chlorine, and the other two are hydrogen; k, m, n, and p are 0 or 1; and ring A is selected from a benzene ring, cyclohexane, and cyclohexene; ##STR00002## where R.sub.2 and R.sub.3 each are selected from alkyl with 1 to 10 carbon atoms, alkenyl with 2 to 10 carbon atoms, fluorinated alkyl, fluorinated alkenyl, cycloalkyl, halogen, and NCS; and ring A and ring B each are selected from a benzene ring, cyclohexane, and cyclohexene.

Claims

1. A liquid crystal (LC) composition for a high-frequency component, comprising at least one compound represented by structural formula I and at least one compound represented by structural formula II: ##STR00127## wherein in structural formula I, R.sub.1 is one of: an alkyl with 1 to 10 carbon atoms, an alkenyl with 2 to 10 carbon atoms, a fluorinated alkyl, a fluorinated alkenyl, and a cycloalkyl; k, m, n, and p are 0 or 1; when n=1, one of X.sub.1, X.sub.2, and X.sub.3 is methyl or chlorine, and the other two are hydrogen; when n=0, one of X.sub.1 and X.sub.3 is methyl or chlorine, and the other one is hydrogen; and ring A of structural formula I is one of: benzene, cyclohexane, and cyclohexene; ##STR00128## wherein in structural formula II, R.sub.2 and R.sub.3 each are selected from one of: an alkyl with 1 to 10 carbon atoms, an alkenyl with 2 to 10 carbon atoms, a fluorinated alkyl, a fluorinated alkenyl, a cycloalkyl, and a halogen; ring A and ring B of structural formula II each are selected from one of: benzene, cyclohexane, and cyclohexene; and wherein a mass proportion of the compounds shown in structural formula (I) is 50% to 99% and a mass proportion of the compounds shown in structural formula (II) is 1% to 40%.

2. The LC composition according to claim 1, wherein the at least one compound represented by structural formula I comprises one or more selected from the group consisting of compounds represented by structural formulae I-A to structural formulae I-L: ##STR00129## ##STR00130## wherein in structural formulae I-A to structural formulae I-L, R.sub.1 is one of: an alkyl with 1 to 10 carbon atoms, an alkenyl with 2 to 10 carbon atoms, a fluorinated alkyl, a fluorinated alkenyl, and a cycloalkyl; one of X.sub.1, X.sub.2 is methyl or chlorine, and the other one is hydrogen for structural formulae I-AI-I; one of X.sub.1, X.sub.2, and X.sub.3 is methyl or chlorine, and the other two are hydrogen for structural formulae I-JI-L.

3. The LC composition according to claim 1, wherein the at least one compound represented by structural formula II is selected from the group consisting of compounds of formulae II-A, II-B, and II-C: ##STR00131## wherein in formulae II-A, II-B, and II-C, R.sub.2 and R.sub.3 each are selected from one of: an alkyl with 1 to 10 carbon atoms, an alkenyl with 2 to 10 carbon atoms, a fluorinated alkyl, a fluorinated alkenyl, a cycloalkyl, and a halogen.

4. The LC composition according to claim 1, further comprising at least one compound represented by structural formula III: ##STR00132## wherein in structural formula III, R.sub.1 is one of: an alkyl with 1 to 10 carbon atoms, an alkenyl with 2 to 10 carbon atoms, a fluorinated alkyl, and a fluorinated alkenyl; X.sub.4, X.sub.5, and X.sub.6 each are H or F; k, m, and n each are 0 or 1; and ring A of structural formula III is one of: benzene, cyclohexane, and cyclohexene; and a mass proportion of the at least one compound represented by structural formula III is 0% to 30%.

5. The LC composition according to claim 1, wherein the LC composition further comprises 0.001% to 1% of an additive.

6. The LC composition according to claim 5, wherein the additive comprises a 2,6-di-tert-butylphenol antioxidant or a light stabilizer.

7. The LC composition according to claim 1, wherein the LC composition has a vertical dielectric loss value tan .sub. less than or equal to 0.008 and a quality factor larger than or equal to 40.

8. A high-frequency component comprising the LC composition according to claim 1.

9. The LC composition according to claim 2, further comprising at least one compound represented by structural formula III: ##STR00133## wherein in structural formula III, R.sub.1 is one of: an alkyl with 1 to 10 carbon atoms, an alkenyl with 2 to 10 carbon atoms, a fluorinated alkyl, and a fluorinated alkenyl; X.sub.4, X.sub.5, and X.sub.6 each are H or F; k, m, and n each are 0 or 1; and ring A of structural formula III is one of: benzene, cyclohexane, and cyclohexene; and a mass proportion of the at least one compound represented by structural formula III is 0% to 30%.

10. The LC composition according to claim 3, further comprising at least one compound represented by structural formula III: ##STR00134## wherein in structural formula III, R.sub.1 is one of: an alkyl with 1 to 10 carbon atoms, an alkenyl with 2 to 10 carbon atoms, a fluorinated alkyl, and a fluorinated alkenyl; X.sub.4, X.sub.5, and X.sub.6 each are H or F; k, m, and n each are 0 or 1; and ring A of structural formula III is one of: benzene, cyclohexane, and cyclohexene; and a mass proportion of the at least one compound represented by structural formula III is 0% to 30%.

11. A high-frequency component comprising the LC composition according to claim 2.

12. A high-frequency component comprising the LC composition according to claim 3.

13. A high-frequency component comprising the LC composition according to claim 4.

14. A high-frequency component comprising the LC composition according to claim 5.

Description

DETAILED DESCRIPTION

(1) In order to make the objectives, contents, and advantages of the present disclosure clearer, specific embodiments of the present disclosure will be further described in detail below with reference to examples.

(2) The present disclosure provides an LC composition for a high-frequency component, including one or more selected from the group consisting of compounds shown in structural formula (I), structural formula (II), and structural formula (III):

(3) ##STR00011## where R.sub.1 is selected from the group consisting of alkyl with 1 to 10 carbon atoms, alkenyl with 2 to 10 carbon atoms, fluorinated alkyl, fluorinated alkenyl, and cycloalkyl; one of X.sub.1, X.sub.2, and X.sub.3 is methyl or chlorine, and the other two are hydrogen; k, m, n, and p are 0 or 1; and ring A is selected from the group consisting of a benzene ring, cyclohexane, and cyclohexene;

(4) ##STR00012## where R.sub.2 and R.sub.3 each are selected from the group consisting of alkyl with 1 to 10 carbon atoms, alkenyl with 2 to 10 carbon atoms, fluorinated alkyl, fluorinated alkenyl, cycloalkyl, halogen, and NCS; and ring A and ring B each are selected from the group consisting of a benzene ring, cyclohexane, and cyclohexene;

(5) ##STR00013## where R.sub.1 is selected from the group consisting of alkyl with 1 to 10 carbon atoms, alkenyl with 2 to 10 carbon atoms, fluorinated alkyl, and fluorinated alkenyl; X.sub.4, X.sub.5, and X.sub.6 each are H or F; k, m, and n each are 0 or 1; and ring A is selected from the group consisting of a benzene ring, cyclohexane, and cyclohexene.

(6) A compound shown in structural formula (I) further preferably has a structure selected from the group consisting of the following structures:

(7) ##STR00014## ##STR00015## where I-A to I-J are further preferably selected from the group consisting of the following structures:

(8) ##STR00016## ##STR00017## ##STR00018## ##STR00019## ##STR00020## ##STR00021##

(9) Compared with the high-frequency LC composition based on isothiocyano disclosed in the prior art, the compound shown in structural formula (I) is characterized in that there is no lateral fluorine substituent in a molecule. In the compounds shown in structural formula (I), methyl, ethyl, and chlorine, with relatively-large volume and relatively-weak polarity, serve as lateral substituents, which can greatly reduce the dielectric loss, reduce the melting point, and improve the low-temperature compatibility of the LC composition.

(10) A compound shown in structural formula (II) further preferably has a structure selected from the group consisting of the following structures:

(11) ##STR00022##

(12) The compound shown in structural formula (II) is composed of two rings, and has the characteristics of low viscosity, low melting point, and low dielectric loss, which can further improve the low-temperature compatibility of the LC composition, greatly reduce the viscosity of the LC composition, and reduce the dielectric loss.

(13) The structural formula II-A more preferably refers to the following specific compounds:

(14) ##STR00023## where II-B further preferably refers to the following structural compounds:

(15) ##STR00024## where II-C further preferably refers to the following structural compounds:

(16) ##STR00025##

(17) A compound shown in structural formula (III) preferably is a specific compound with the following structure:

(18) ##STR00026## ##STR00027##

(19) The compound shown in structural formula (III) has a wide LC phase range, low viscosity, and a large dielectric constant (especially at a low frequency of 1 KHz), which can adjust the LC phase range and low-frequency dielectric constant of the composition.

(20) In a preferred embodiment of the present disclosure, the LC composition includes one or more selected from the group consisting of compounds shown in structural formula (I) and one or more selected from the group consisting of compounds shown in structural formula (II). In another preferred embodiment of the present disclosure, the LC composition includes one or more selected from the group consisting of compounds shown in structural formula (I), one or more selected from the group consisting of compounds shown in structural formula (II), and one or more selected from the group consisting of compounds shown in structural formula (III).

(21) The LC composition according to the present disclosure preferably includes 50% to 99%, preferably 60% to 95%, and more preferably 70% to 90% (based on a total amount of the composition) of a compound shown in structural formula (I) and 1% to 40%, preferably 5% to 30%, and more preferably 10% to 20% (based on a total amount of the composition) of a compound shown in structural formula (II). The LC composition of the present disclosure may further include 0% to 30%, preferably 5% to 25%, and more preferably 10% to 20% (based on a total amount of the composition) of a compound shown in structural formula (III).

(22) The LC composition according to the present disclosure may further include 0.001% to 1% of an additive, such as a 2,6-di-tert-butylphenol antioxidant and a light stabilizer T770.

(23) The LC composition according to the present disclosure includes various compounds (preferably 3 to 20, more preferably 5 to 18, and more preferably 7 to 15 compounds). These compounds can be mixed in a conventional manner: the compounds each are weighed according to a predetermined mass proportion, then heated and thoroughly mixed through magnetic stirring or ultrasonic stirring until the components are completely dissolved, and then filtered. The LC composition can also be prepared in another conventional manner, for example, the so-called pre-mixture or so-called multi-bottle system is adopted, and components themselves in the system are ready-to-use mixtures.

(24) The performance of LC at a high frequency is tested by a test method reported in the following literature: Penirschke, A. (2004). Cavity perturbation method for characterization of liquid crystals up to 35 GHz. Microwave Conference, 2004. 34th European.

(25) LC is introduced into PTFE or fused quartz capillaries, and the packed capillaries are introduced into the middle of a chamber with a resonance frequency of 19 GHz. An input signal source is then applied, and a vector network analyzer is used to record a result of an output signal. Changes in resonance frequency and Q factor between the capillaries packed with the LC and blank capillaries are measured, and dielectric constant and loss tangent values are calculated. Dielectric constant components perpendicular and parallel to an LC orientation vector are obtained through alignment of LCs in a magnetic field, a direction of the magnetic field is set accordingly, and rotation is subsequently conducted by 90 accordingly.

(26) The LC composition of the present disclosure has tunability T of preferably higher than or equal to 0.25 and more preferably higher than or equal to 0.30; a vertical dielectric loss tan .sub. of preferably less than or equal to 0.008 and more preferably less than or equal to 0.007; and a quality factor of preferably larger than or equal to 40 and more preferably larger than or equal to 50. The LC composition of the present disclosure has a nematic phase temperature range of preferably 0 C. to 90 C. or above and more preferably 10 C. to 100 C. or above; rotational viscosity 1 of preferably less than or equal to 1,200 mPa.Math.s and more preferably less than or equal to 1,000 mPa.Math.s; and a dielectric constant of preferably larger than or equal to 7.0 and more preferably larger than or equal to 8.0 at a low frequency of 1 KHz.

(27) The LC composition according to the present disclosure is very suitable for the fabrication of a microwave component, such as a phase shifter that can be tuned by applying an external magnetic or electric field. These phase shifters can work at a UHF-frequency band (0.3 GHz to 1 GHz), an L-frequency band (1 GHz to 2 GHz), an S-frequency band (2 GHz to 4 GHz), a C-frequency band (4 GHz to 8 GHz), an X-frequency band (8 GHz to 12 GHz), a Ku-frequency band (12 GHz to 18 GHz), a K-frequency band (18 GHz to 27 GHz), a Ka-frequency band (27 GHz to 40 GHz), a V-frequency band (50 GHz to 75 GHz), a W-frequency band (75 GHz to 110 GHz), and a frequency of up to 1 THz. The construction of the phase shifter according to the present disclosure is known to experts. Typically, loaded line phase shifters, inverted microstrip lines, or finline phase shifters and preferably antipodal finline phase shifters, slotted phase shifters, microstrip line phase shifters, or coplanar waveguide (CPW) phase shifters are used. These components enable a reconstructed antenna array.

(28) % represents a mass percentage, and measured properties in the embodiments are as follows: n: birefringence anisotropy at 20 C. and 589 nm; T.sub.ni: clearing point; Tm: melting point; .sub.1: rotational viscosity at 20 C.; and : dielectric anisotropy at 20 C., 1 KHz, and 19 GHz.

Example 1

(29) TABLE-US-00001 TABLE1 Composition in Example 1 and performance thereof Mass Monomer structure proportion/% Test data 8 5 Tcl=147C. Tm40C. (20C.,1KHz)=11.8 n(20C.,589nm)=0.37 .sub.1=890mPa.Math.s .sub.(20C.,19GHz)=2.55 .sub.//(20C.,19GHz)=3.70 (20C.,19GHz)=1.15 tan.sub.(20C.,19GHz)=0.0054 tan.sub.//(20C.,19GHz)=0.0037 =0.311 =57.6 0 8 9 4 6 10 5 10 10 5 5 0 5 10

Example 2

(30) TABLE-US-00002 TABLE2 CompositioninExample2andperformancethereof Mass Monomerstructure proportion/% Testdata 8 7 Tcl=157C. Tm40C. (20C.,1KHz)=10.7 n(20C.,589nm)=0.38 .sub.1=890mPa.Math.s .sub.(20C.,19GHz)=2.42 .sub.//(20C.,19GHz)=3.51 (20C.,19GHz)=1.09 tan.sub.(20C.,19GHz)=0.0044 tan.sub.//(20C.,19GHz)=0.0029 =0.311 =70.6 5 10 5 5 10 5 0 10 10 5 5 15

Example 3

(31) TABLE-US-00003 TABLE 3 Composition in Example 3 and performance thereof Mass Monomer structure proportion/% Test data 10 10 Tcl = 152 C. Tm 30 C. (20 C., 1 KHz) = 9.2 n(20 C., 589 nm) = 0.36 .sub.1 = 659 mPa .Math. s .sub.(20 C., 19 GHz) = 2.43 .sub.//(20 C., 19 GHz) = 3.46 (20 C., 19 GHz) = 1.03 tan .sub.(20 C., 19 GHz) = 0.0043 tan .sub.// (20 C., 19 GHz) = 0.0028 = 0.298 = 69.2 5 10 10 0 5 10 5 15 15 5

Example 4

(32) TABLE-US-00004 TABLE 4 Composition in Example 4 and performance thereof Mass Monomer structure proportion/% Test data 5 Tcl = 132 C. Tm 40 C. (20 C., 1 KHz) = 12.8 n(20 C., 589 nm) = 0.38 .sub.1 = 664 mPa .Math. s .sub.(20 C., 19 GHz) = 2.47 .sub.//(20 C., 19 GHz) = 3.61 (20 C., 19 GHz) = 1.14 tan .sub.(20 C., 19 GHz) = 0.0069 tan .sub.// (20 C., 19 GHz) = 0.0046 = 0.316 = 45.8 5 4 5 0 10 7 12 12 10 13 12 5

Example 5

(33) TABLE-US-00005 TABLE 5 Composition in Example 5 and performance thereof Mass Monomer structure proportion/% Test data 5 Tcl = 157 C. Tm 40 C. (20 C., 1 KHz) = 10.5 n(20 C., 589 nm) = 0.37 .sub.1 = 794 mPa .Math. s .sub.(20 C., 19 GHz) = 2.48 .sub.//(20 C., 19 GHz) = 3.57 (20 C., 19 GHz) = 1.09 tan .sub.(20 C., 19 GHz) = 0.0055 tan .sub.// (20 C., 19 GHz) = 0.0036 = 0.305 = 55.5 8 0 7 5 10 7 10 11 10 13 9 5

Example 6

(34) TABLE-US-00006 TABLE 6 Composition in Example 6 and performance thereof Mass Monomer structure proportion/% Test data 0 4 Tcl = 143 C. Tm 40 C. (20 C., 1 KHz) = 10.8 n(20 C., 589 nm) = 0.35 .sub.1 = 939 mPa .Math. s .sub.(20 C., 19 GHz) = 2.42 .sub.//(20 C., 19 GHz) = 3.46 (20 C., 19 GHz) = 1.04 tan .sub.(20 C., 19 GHz) = 0.0039 tan .sub.// (20 C., 19 GHz) = 0.0022 = 0.301 = 77.2 5 5 8 9 5 5 7 4 5 00 8 01 10 02 18 03 7

Comparative Example 1

(35) Patent CN107955630A discloses an LC composition for a high-frequency component, including a fluorine-substituted isothiocyano-containing LC compound. In Example 1 of this patent, the following composition and performance parameters thereof are disclosed:

(36) TABLE-US-00007 Mass Monomer structure proportion/% Test data 04 05 20 Tcl = 134 C. (20 C., 1 KHz) = 22.6 .sub.1 = 324 mPa .Math. s .sub.(20 C., 19 GHz) = 2.3886 .sub.//(20 C., 19 GHz) = 3.3697 tan .sub. (20 C., 19 GHz) = 0.0128 tan .sub.// (20 C., 19 GHz) = 0.0069 = 0.291 = 22.7 15 06 15 07 15 08 10 09 15 0 10

(37) Compared with Comparative Example 1, the examples of the present disclosure have significantly-reduced dielectric losses and multiplied quality factors.

Comparative Example 2

(38) In Example 15 of Patent CN105368465A, a composition including fluorine-substituted isothiocyano-containing LC compound and properties thereof such as high-frequency dielectric constant are disclosed:

(39) TABLE-US-00008 Mass Monomer structure proportion/% Test data 10 Tcl = 126.5 C. .sub.1 = 297 mPa .Math. s .sub.(20 C., 19 GHz) = 2.36 .sub.//(20 C., 19 GHz) = 3.44 tan .sub. (20 C., 19 GHz) = 0.0115 tan .sub.// (20 C., 19 GHz) = 0.0065 = 0.313 = 27.2 10 10 14 13 13 16 7 7

(40) Compared with Comparative Example 2, the examples of the present disclosure have significantly-reduced dielectric losses and multiplied quality factors.

Comparative Example 3

(41) In Example N52 of Patent CN110499163A, a composition including fluorine-substituted isothiocyano-containing LC compound and properties thereof such as high-frequency dielectric constant are disclosed:

(42) TABLE-US-00009 Mass Monomer structure proportion/% Test data 0 6 Tcl = 159.1 C. (20 C., 1 KHz) = 14.0 .sub.1 = 564 mPa .Math. s .sub.(20 C., 19 GHz) = 2.4198 .sub.//(20 C., 19 GHz) = 3.6173 tan .sub. (20 C., 19 GHz) = 0.0084 tan .sub.//(20 C., 19 GHz) = 0.0052 = 0.331 = 39.4 10 28 7 13 20 16

(43) Compared with Comparative Example 3, the examples of the present disclosure have significantly-reduced dielectric losses and significantly-improved quality factors.

(44) The above described are preferred implementations of the present disclosure, and it should be noted that those of ordinary skill in the art can make various improvements and modifications without departing from the technical principles of the present disclosure. These improvements and modifications should be regarded as falling within the protection scope of the present disclosure.