Polymer, composition for low dielectric substrate, cured product, and electronic device using same

Abstract

To provide a composition for a low dielectric substrate which is suitably usable for a next generation communication device and a radar whose frequency is increased, and has low dielectric property and good substrate moldability.SOLUTION: A polymer for a low dielectric substrate, which is composed of a liquid crystal compound that has less conjugation and less polar groups and has a polymerizable group having high linearity and symmetric property of molecules, is used as a prepolymer, and a polymer having lower dielectric property and better substrate moldability than a conventional resin for a low dielectric substrate by curing the composition containing the prepolymer can be achieved.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polymer for low dielectric substrates made of a liquid crystal compound, a composition for low dielectric substrates using the polymer, and a cured product using the same. In particular, the present invention relates to a material for high frequency substrates and peripheral materials, and a cured product and electronic device using the same. [Background technology]

[0002] In recent years, with the shift to 5G and beyond 5G and 6G in communication devices, the frequency of electrical signals on electronic boards and the frequency of radio waves transmitted and received by antennas have also increased, resulting in problems with signal loss in signal processing circuit boards and antenna boards. Therefore, there is a demand for resin materials used in boards with low dielectric constants and low dielectric dissipation factors, and resins such as liquid crystal polymers (LCPs), polyphenylene ethers (PPEs), cycloolefin polymers (COPs), and fluororesins (PTFEs) are beginning to be used in place of conventional polyimides and epoxy resins. Low-dielectric substrates are available in a lineup of materials with a dielectric constant of 3.0 or less, and those containing high thermal conductive fillers have a dielectric constant of 3.5 or less, but there is a demand for the development of materials with even lower dielectric constants.

[0003] Current materials for high-frequency substrates are thermoplastic resins, which have many difficulties in use, such as the need to mold and bond them at high temperatures and poor adhesion between resins and to the copper foil that serves as the electrode. Patent Document 1 focuses on the molecular structure of liquid crystal polymers and studies how to further lower the dielectric constant of liquid crystal polymers. However, liquid crystal polymers have a high melting point, requiring processing temperatures of 350°C or higher, making thermal lamination and thermal bonding difficult. Patent Document 2 focuses on the molecular structure of PPE and studies how to turn it into a varnish by increasing its solubility in solvents. By turning it into a varnish, PPE can be formed into a film by a coating method, making it usable for insulating varnish coatings. However, this requires the use of a solvent with high solubility, and there are many problems with curing, such as the possibility of re-dissolution in the solvent when laminating multiple layers. Therefore, as described in Non-Patent Document 1, there is a need for the development of a composition for low-dielectric substrates that can be applied like an insulating coating varnish and cured easily.

[0004] Polymerizable liquid crystal compounds are resin raw materials that have the potential to exhibit performance equal to or superior to thermosetting resins and liquid crystal polymers. To obtain good substrate moldability with liquid crystal polymers, it is necessary to reduce the melt viscosity or make them more soluble in solvents. To achieve this, it is necessary to reduce the crystallinity that liquid crystal polymers possess. On the other hand, by curing polymerizable liquid crystal compounds while maintaining their crystallinity, it is possible to design materials that combine the low dielectric properties of liquid crystal polymers with the easy moldability of thermosetting resins. For example, Patent Document 3 discloses that when a highly linear polymerizable liquid crystal compound is aligned and cured, it exhibits higher thermal conductivity in the alignment direction than a typical thermosetting resin. Furthermore, Patent Document 4 discloses that a thermosetting resin material with even higher thermal conductivity can be formed by combining a polymerizable liquid crystal compound with a heat-dissipating filler. However, in these examples, the focus is on achieving high thermal conductivity, and low dielectric properties are not considered.

[0005] Low-dielectric substrates can be classified into rigid substrates, which are composites of thermosetting resins such as epoxy resins and glass cloth, and flexible substrates, which use resin films such as polyimide. When applying polymerizable liquid crystal compounds to these substrates, the former has a problem: the polymerizable liquid crystal compounds have a low molecular weight and low melt viscosity, so even if they are impregnated into glass cloth, they may flow out before hardening. The latter has a problem: the resin film of the polymerizable liquid crystal compound is brittle and prone to cracking when it has high crystallinity and a low molecular weight. When a polymerizable liquid crystal compound is combined with a heat-dissipating filler, prepolymerization is possible by pre-kneading the compound at a temperature at which the compound will not fully cure (Patent Document 4). However, when glass cloth is used, pre-kneading is not possible in order to maintain the shape of the glass cloth. Furthermore, when a polymerizable liquid crystal compound is made into a film by a coating method, if the viscosity is low, only a thin film can be obtained, making it difficult to use as a substrate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-189734 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-67894 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-265527 [Patent Document 4] Republished Publication No. 2015 / 170744 [Non-patent literature]

[0007] [Non-Patent Document 1] RF World No.40, pp97-111, 2017 Summary of the Invention [Problem to be solved by the invention]

[0008] As described above, an object of the present invention is to provide a composition for low dielectric substrates that has low dielectric properties and good substrate moldability and can be suitably used in next-generation communication devices, radar, and the like, which are becoming increasingly high-frequency. [Means for solving the problem]

[0009] The present inventors have conducted intensive research to solve these problems, and as a result, have found that by polymerizing a polymerizable liquid crystal compound having a structure with a low dielectric constant and high thermal conductivity in advance to form a prepolymer, and then curing a composition containing the prepolymer, it is possible to realize a polymer that exhibits a dielectric constant lower than or equal to that of conventional low-dielectric-constant resins and good substrate moldability, and have completed the present invention.

[0010] The polymer according to the first aspect of the present invention is obtained by polymerizing a liquid crystal compound having a polymerizable group at its terminal, which is represented by formula (1). R 1a -Z 1 -A 1 -Z 2 -A 2 -(Z 3 -A 3 ) m1 -Z 4 -R 1b (1) In formula (1), A 1 , A 2 , and A 3 are independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, bicyclo[2.2.2]octo-1,4-diyl, bicyclo[3.1.0]hex-3,6-diyl, or fluorene-2,7-diyl, in which at least one -CH2- is optionally replaced with -O-, at least one -CH= is optionally replaced with -N=, at least one hydrogen is halogen or alkyl having 1 to 10 carbon atoms in which at least one hydrogen is optionally replaced with halogen, and in this alkyl, at least one -CH2- is optionally replaced with -O-, -CO-, -COO-, -OCO-, or -C=C-; Z 1 , Z 2 , Z 3 , and Z 4are independently a single bond or alkylene having 1 to 22 carbon atoms, in which at least one -CH- may be replaced by -O-, -S-, -CO-, -COO-, -OCO-, -SO-, -CH=CH-, -CF=CF-, -CH=N-, -N=CH-, or -N=N-, and at least one hydrogen may be replaced by halogen; m1 is 0, 1, or 2; In the formula, Z 3 or A 3 If there are multiple, they may be the same or different, R 1a and R 1b are independently a group selected from the polymerizable groups represented by formulas (PG-1) to (PG-6), TIFF0007739863000001.tif56125 In formulas (PG-1) to (PG-6), R b is hydrogen, halogen, -CF3, or alkyl having 1 to 5 carbon atoms, q is 0 or 1, and in the formula, R b When there are a plurality of, they may be the same or different. When configured in this manner, the polymer has few conjugated or polar groups and has structural units with high molecular linearity and symmetry, and when a composition containing this as a prepolymer is cured, it exhibits good low dielectric properties and substrate moldability.

[0011] The polymer related to the second aspect of the present invention is obtained by polymerizing a liquid crystal compound having a polymerizable group at an end, represented by at least one selected from the group consisting of formula (1-1), formula (1-2), and formula (1-3), in the polymer related to the first aspect of the present invention. R 1a -Z 1 -A 1 -Z 2 -A 2 -Z 4 -R 1b (1-1) R 1a -Z 1 -A 1 -Z2 -A 2 -Z 3 -A 3 -Z 4 -R 1b (1-2) R 1a -Z 1 -A 1 -Z 2 -A 2 -Z 3 -A 3 -Z 3 -A 3 -Z 4 -R 1b (1-3) In formulas (1-1) to (1-3), A 1 , A 2 , and A 3 are independently 1,4-cyclohexylene, 1,4-phenylene in which at least one hydrogen may be replaced by halogen or alkylene having 1 to 10 carbon atoms, bicyclo[2.2.2]octo-1,4-diyl, bicyclo[3.1.0]hex-3,6-diyl, or fluorene-2,7-diyl in which at least one hydrogen may be replaced by halogen or alkylene having 1 to 10 carbon atoms; Z 1 , Z 2 , Z 3 , and Z 4 are independently a single bond, -(CH2) a -, -O(CH2) a -, -(CH2) a O-, -O(CH2) a O-, -COO-, -OCO-, -CH=CH-COO-, -OCO-CH=CH-, -(CH2) a -COO-, -OCO-(CH2) a -, -CH=CH-, -SO2-, -OCF2-, or -CF2O-, where a is an integer of 1 to 20; In the formula, Z 3 or A 3 If there are multiple, they may be the same or different, R 1a and R 1bare independently polymerizable groups represented by formula (PG-1), (PG-5), or (PG-6), TIFF0007739863000002.tif2684 In formulas (PG-1), (PG-5), and (PG-6), R b is hydrogen, halogen, -CF3, or alkyl having 1 to 5 carbon atoms, q is 0 or 1, and in the formula, R b When there are a plurality of, they may be the same or different. When configured in this manner, the polymer has excellent heat and light curing properties, and a substrate obtained by curing a composition containing this as a prepolymer has good substrate moldability and dimensional stability.

[0012] The polymer related to the third aspect of the present invention is the polymer related to the first or second aspect of the present invention, obtained by polymerizing a liquid crystal compound having a polymerizable group at its terminal, which is represented by at least one selected from the group consisting of formula (1-1-1), formula (1-1-2), and formula (1-1-3). TIFF0007739863000003.tif4989 In formulas (1-1-1) to (1-1-3), Z 1 , Z 2 and Z 4 are independently a single bond, -(CH2) a -, -O(CH2) a -, -(CH2) a O-, -O(CH2) a O-, -COO-, -OCO-, -CH=CH-COO-, -OCO-CH=CH-, -(CH2) a -COO-, -OCO-(CH2) a -, -CH=CH-, -SO2-, -OCF2-, or -CF2O-, where a is an integer of 1 to 20; X is fluorine or methyl; n is an integer from 0 to 4, When n is 2 or more, and when there are a plurality of X's in the formula, they may be the same or different, R 1aand R 1b are independently polymerizable groups represented by formula (PG-1), (PG-5), or (PG-6), TIFF0007739863000004.tif2684 In formulas (PG-1), (PG-5), and (PG-6), R b is hydrogen, halogen, —CF3, or alkyl having 1 to 5 carbon atoms, q is 0 or 1, and in the formula, R b When there are a plurality of, they may be the same or different. In this way, the polymer can be easily produced, and a substrate obtained by curing a composition containing the polymer as a prepolymer has low dielectric properties.

[0013] The polymer according to the fourth aspect of the present invention is the polymer according to the first or second aspect of the present invention, obtained by polymerizing a liquid crystal compound having a polymerizable group at its terminal, which is represented by at least one selected from the group consisting of formulas (1-2-1) to (1-2-6): TIFF0007739863000005.tif104112 In formulas (1-2-1) to (1-2-6), Z 1 , Z 2 , Z 3 and Z 4 are independently a single bond, -(CH2) a -, -O(CH2) a -, -(CH2) a O-, -O(CH2) a O-, -COO-, -OCO-, -CH=CH-COO-, -OCO-CH=CH-, -CHCH-COO-, -OCO-CHCH-, -CH=CH-, -SO-, -OCF-, or -CFO-, where a is an integer of 1 to 20; X is fluorine or methyl; n is an integer from 0 to 4, When n is 2 or more, and when there are a plurality of X's in the formula, they may be the same or different, R 1a and R1b are independently polymerizable groups represented by formula (PG-1), (PG-5), or (PG-6), TIFF0007739863000006.tif2684 In formulas (PG-1), (PG-5), and (PG-6), R b is hydrogen, halogen, —CF3, or alkyl having 1 to 5 carbon atoms, q is 0 or 1, and in the formula, R b When there are a plurality of, they may be the same or different. In this configuration, the polymer has a high melt viscosity, and the substrate moldability of a composition containing this as a prepolymer can be improved.

[0014] The polymer according to the fifth aspect of the present invention is the polymer according to the first or second aspect of the present invention, obtained by polymerizing a liquid crystal compound having a polymerizable group at its terminal, which is represented by at least one selected from the group consisting of formulas (1-3-1) to (1-3-9): TIFF0007739863000007.tif161122 In formulas (1-3-1) to (1-3-9), Z 1 , Z 2 , Z 3 and Z 4 are independently a single bond, -(CH2) a -, -O(CH2) a -, -(CH2) a O-, -O(CH2) a O-, -COO-, -OCO-, -CH=CH-COO-, -OCO-CH=CH-, -(CH2) a -COO-, -OCO-(CH2) a -, -CH=CH-, -SO2-, -OCF2-, or -CF2O-, where a is an integer of 1 to 20; Z in the formula 3 may be the same or different, X is fluorine or methyl; n is an integer from 0 to 4, When n is 2 or more, and when there are a plurality of X's in the formula, they may be the same or different, R 1a and R 1b are independently polymerizable groups represented by formulae (PG-1), (PG-5), and (PG-6), TIFF0007739863000008.tif2684 In formulas (PG-1), (PG-5) and (PG-6), R b is hydrogen, halogen, -CF3, or alkyl having 1 to 5 carbon atoms, q is 0 or 1, and in the formula, R b When there are a plurality of, they may be the same or different. In this configuration, the polymer has a high melt viscosity, and the substrate moldability of a composition containing this as a prepolymer can be improved.

[0015] The polymer according to the sixth aspect of the present invention is the polymer according to any one of the first to fifth aspects of the present invention, wherein R 1a and R 1b is a polymerizable group represented by formula (PG-1). TIFF0007739863000009.tif2826 formula (PG-1), R b is hydrogen, halogen, -CF3, or alkyl having 1 to 5 carbon atoms, and in the formula, R b When there are a plurality of, they may be the same or different. When configured in this manner, the polymer is a polymerization product from a liquid crystal compound having a particularly preferred polymerizable group, and a composition containing this as a prepolymer has excellent curability, solubility in solvents, and ease of handling.

[0016] The polymer according to the seventh aspect of the present invention is obtained by polymerizing a liquid crystal compound having a polymerizable group at its terminal, represented by formula (1-1-1a) or (1-2-1a), in the polymer according to any one of the first to sixth aspects of the present invention. TIFF0007739863000010.tif44147 In formulas (1-1-1a) and (1-2-1a), R b is hydrogen, halogen, -CF3, or alkyl having 1 to 5 carbon atoms; Z 2 and Z 3 are independently a single bond, -(CH2) a -, -O(CH2) a -, -(CH2) a O-, -O(CH2) a O-, -COO-, -OCO-, -CH=CH-COO-, -OCO-CH=CH-, -(CH2) a -COO-, -OCO-(CH2) a -, -CH=CH-, -SO2-, -OCF2-, or -CF2O-, where a is an integer of 1 to 20; m is an integer from 0 to 20; M is a single bond or oxygen; X is fluorine or methyl; n is an integer from 0 to 4, When n is 2 or more, and when there are a plurality of X's in the formula, they may be the same or different, In the formula, R b When there are a plurality of , m, or M, they may be the same or different. When configured in this manner, the polymer is a polymerization product of a suitable liquid crystal compound, and a substrate obtained from a composition containing this as a prepolymer has good substrate moldability.

[0017] The polymer according to the eighth aspect of the present invention is obtained by polymerizing a liquid crystal compound having a polymerizable group at its terminal, which is represented by at least one selected from the group consisting of formulas (1-1-2a), (1-1-3a), (1-2-5a), and (1-2-6a) in the polymer according to any one of the first to sixth aspects of the present invention. TIFF0007739863000011.tif80148 In formulas (1-1-2a), (1-1-3a), (1-2-5a), and (1-2-6a), R b is hydrogen, halogen, -CF3, or alkyl having 1 to 5 carbon atoms; Z 2 and Z 3 are independently a single bond, -(CH2) a -, -O(CH2) a -, -(CH2) a O-, -O(CH2) a O-, -COO-, -OCO-, -CH=CH-COO-, -OCO-CH=CH-, -(CH2) a -COO-, -OCO-(CH2) a -, -CH=CH-, -SO2-, -OCF2-, or -CF2O-, where a is an integer of 1 to 20; m is an integer from 0 to 20; M is a single bond or oxygen; X is fluorine or methyl; n is an integer from 0 to 4, When n is 2 or more, and when there are a plurality of X's in the formula, they may be the same or different, In the formula, R b When there are a plurality of , m, or M, they may be the same or different. In this configuration, the polymer is a polymerization product of a suitable liquid crystal compound, and a substrate obtained from a composition containing this as a prepolymer has excellent low dielectric properties.

[0018] The polymer according to the ninth aspect of the present invention is the polymer according to the seventh or eighth aspect of the present invention, wherein R b is hydrogen, fluorine, -CF3, or methyl, Z 2 and Z 3 are independently a single bond, -(CH2) a -, -O(CH2) a -, -(CH2) a O-, -O(CH2) a and m is an integer of 0 to 12. When configured in this manner, the polymer is a polymerization product of a particularly suitable liquid crystal compound, and a substrate obtained from a composition containing this as a prepolymer has excellent low dielectric properties and particularly good substrate moldability.

[0019] The polymer according to the tenth aspect of the present invention is a product obtained by polymerizing the polymer according to any one of the first to ninth aspects of the present invention in the presence of a mercaptan chain transfer agent. This allows the production of a polymer having a desirable weight-average molecular weight, and a substrate produced from a composition containing the polymer as a prepolymer exhibits excellent adhesion to copper foil and the like.

[0020] The polymer according to the eleventh aspect of the present invention is a product of polymerization of the polymer according to the tenth aspect of the present invention in the presence of a mercaptan chain transfer agent having a carboxyl group in the molecule. This allows the production of a polymer having a desirable weight-average molecular weight, and substrates produced from compositions containing the polymer as a prepolymer exhibit excellent adhesion to copper foil and the like.

[0021] The polymer according to the twelfth aspect of the present invention is the polymer according to any one of the first to eleventh aspects of the present invention, wherein the weight average molecular weight is 300,000 or less. When configured in this manner, the polymer has good melt viscosity and good solubility in solvents, and a composition containing the polymer as a prepolymer has good substrate moldability.

[0022] The polymer according to the thirteenth aspect of the present invention is the polymer according to any one of the first to eleventh aspects of the present invention, wherein the weight average molecular weight is 50,000 or less. When configured in this manner, the polymer has an appropriate melt viscosity and solubility in an appropriate solvent, and a composition containing the polymer as a prepolymer has particularly excellent substrate moldability.

[0023] A composition for low dielectric substrates according to a fourteenth aspect of the present invention contains the polymer according to any one of the first to thirteenth aspects of the present invention. By configuring in this way, it is possible to obtain a composition for low dielectric substrates that is excellent in manufacturability, substrate formability, and low dielectric properties.

[0024] A composition for low dielectric substrates according to a fifteenth aspect of the present invention is the composition for low dielectric substrates according to the fourteenth aspect of the present invention, further comprising a non-polymerizable liquid crystal compound. When configured in this manner, the composition for a low dielectric substrate has liquid crystal properties suitable for use as a low dielectric substrate material.

[0025] A composition for low dielectric substrates according to a sixteenth aspect of the present invention is the composition for low dielectric substrates according to the fourteenth or fifteenth aspect of the present invention, further comprising an inorganic filler. When configured in this manner, the composition for low dielectric substrates can improve heat dissipation and processability.

[0026] A composition for low dielectric substrates according to a seventeenth aspect of the present invention is the composition for low dielectric substrates according to the sixteenth aspect of the present invention, wherein the inorganic filler is at least one selected from the group consisting of spherical silica, pulverized silica, hollow silica, fumed silica, aluminum nitride, boron nitride, magnesium oxide, aluminum oxide, zinc oxide, titanium oxide, aluminum oxide, magnesium hydroxide, and aluminum hydroxide. When the composition for low dielectric substrates is constructed in this manner, a cured product having high strength and low dielectric tangent is obtained in the case of a silicon compound, and high thermal conductivity and low dielectric loss is obtained in the case of a metal oxide, metal hydroxide, or metal nitride.

[0027] The cured product according to the eighteenth aspect of the present invention is a cured product obtained by curing the composition for low dielectric substrates according to any one of the fourteenth to seventeenth aspects of the present invention. By configuring in this way, the cured product can have improved heat dissipation properties, low dielectric properties, processability, and strength.

[0028] The cured product according to the nineteenth aspect of the present invention is the cured product according to the eighteenth aspect of the present invention, wherein the relative dielectric constant at 10 GHz is less than 3.0. When configured in this manner, the cured product is suitable as a material for next-generation high-speed, high-frequency communication devices that require a low dielectric constant.

[0029] The cured product according to the twentieth aspect of the present invention is the cured product according to the eighteenth or nineteenth aspect of the present invention, wherein the thermal conductivity is 1 W / m·K or more. When configured in this manner, the cured product becomes a material suitable for use in electronic substrates that require heat dissipation properties.

[0030] An insulating film according to a twenty-first aspect of the present invention uses the cured product according to the nineteenth or twentieth aspect of the present invention. When configured in this manner, the insulating film has excellent low dielectric properties, resulting in low transmission loss in the high frequency range, making it suitable as a material for next-generation high-speed, high-frequency communication devices.

[0031] A film according to the twenty-second aspect of the present invention uses the cured product according to the nineteenth or twentieth aspect of the present invention. When configured in this manner, the film has excellent low dielectric properties, resulting in low transmission loss in the high frequency range, making it suitable as a material for next-generation high-speed, high-frequency communication devices.

[0032] A sheet according to a twenty-third aspect of the present invention uses the cured product according to the nineteenth or twentieth aspect of the present invention. When configured in this manner, the sheet has excellent low dielectric properties, resulting in low transmission loss in the high frequency range, making it suitable as a material for next-generation high-speed, high-frequency communication devices.

[0033] An electronic device according to a 24th aspect of the present invention uses the cured product according to the 19th or 20th aspect of the present invention, the insulating film according to the 21st aspect of the present invention, the film according to the 22nd aspect of the present invention, or the sheet according to the 23rd aspect of the present invention. Such a configuration enables the electronic device to perform high-speed communication, large-capacity communication, and low power consumption, for example. [Effects of the Invention]

[0034] A composition for low dielectric substrates containing the polymer of the present invention as a prepolymer has good substrate moldability and, in addition, the cured product has low dielectric properties, and is therefore suitable for, for example, low dielectric circuit boards, low dielectric antenna substrates, low dielectric coating films, low dielectric adhesives, etc. Electronic devices using low dielectric circuit boards, etc. containing the composition for low dielectric substrates of the present invention are excellent in high-speed, large-capacity communication, low power consumption, low latency, multiple connections, etc. BEST MODE FOR CARRYING OUT THE INVENTION

[0035] The polymer, composition for low dielectric substrates, cured product, insulating film, film and sheet manufacturing methods of the present invention will be described in detail below. The terms used in this specification are as follows. "Liquid crystal compound" is a general term for compounds that have a liquid crystal phase such as a nematic phase or a smectic phase, and compounds that do not have a liquid crystal phase but have physical properties specific to liquid crystals such as dielectric anisotropy, refractive index anisotropy, and magnetic susceptibility anisotropy, and are useful as components of liquid crystal compositions. Additionally, "(meth)acryloyloxy" means acryloyloxy or methacryloyloxy, "(meth)acrylate" means acrylate or methacrylate, and "(meth)acrylic acid" means acrylic acid or methacrylic acid.

[0036] The meaning of a phrase such as "at least one -CH2- in the alkyl may be replaced with -O-, -CO-, or the like" is shown below as an example. For example, groups in which at least one -CH2- in C4H9- is replaced with -O- or -CH=CH- include C3H7O-, CH3-O-(CH2)3-, CH3-O-CH2-O-, H2C=CH-(CH2)3-, CH3-CH=CH-(CH2)2-, CH3-CH=CH-CH2-O-, etc. Thus, the term "at least one" means "at least one selected without distinction." In addition, in consideration of the stability of the compound, CH3-O-CH2-O-, in which oxygen atoms are not adjacent to each other, is preferred to CH3-OO-CH2-, in which oxygen atoms are adjacent to each other.

[0037] The polymer of the present invention is obtained by polymerizing a liquid crystal compound having a polymerizable group at its terminal, represented by formula (1). R 1a -Z 1 -A 1 -Z 2 -A 2 -(Z 3 -A 3 ) m1 -Z 4 -R 1b (1) In formula (1), A 1 , A 2 , and A 3 are independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, bicyclo[2.2.2]octo-1,4-diyl, bicyclo[3.1.0]hex-3,6-diyl, or fluorene-2,7-diyl, in which at least one -CH2- is optionally replaced by -O-, at least one -CH= is optionally replaced by -N=, at least one hydrogen is optionally replaced by halogen, or alkyl having 1 to 10 carbon atoms in which at least one hydrogen is optionally replaced by halogen, and in this alkyl, at least one -CH2- is optionally replaced by -O-, -CO-, -COO-, -OCO-, or -C=C-; Z 1 , Z 2 , Z3 , and Z 4 are independently a single bond or an alkylene having 1 to 22 carbon atoms, in which at least one -CH2- may be replaced by -O-, -S-, -CO-, -COO-, -OCO-, -SO2-, -CH=CH-, -CF=CF-, -CH=N-, -N=CH-, or -N=N-, and at least one hydrogen may be replaced by a halogen atom; m1 is 0, 1, or 2, and in the formula, Z 3 or A 3 If there are multiple, they may be the same or different, and R 1a and R 1b are independently a group selected from the polymerizable groups represented by formulas (PG-1) to (PG-6), and in formulas (PG-1) to (PG-6), R b is hydrogen, halogen, -CF3, or alkyl having 1 to 5 carbon atoms, q is 0 or 1, and in the formula, R b When there are a plurality of, they may be the same or different. TIFF0007739863000012.tif56125

[0038] "Compound (1)" means a liquid crystal compound represented by the above formula (1), and may also mean at least one compound represented by formula (1). The same applies to "compound (1-1)," and compounds (1-1) to (1-3) are collectively referred to as "compound (1)." The "composition (1) for low dielectric substrates" means that it contains a polymer of the compound (1). The "polymer (1)" means that it is obtained by polymerizing the composition (1) for low dielectric substrates. One compound (1) is a compound having a plurality of A's. 3 When any two A 3 may be the same or different. 3 When any two A 3 may be the same or different. This rule applies to Z 3 Or, R b , and X, and other symbols, groups, etc.

[0039] [Liquid crystal compound] The compound (1) used in the present invention has a liquid crystal skeleton (rod-shaped mesogenic skeleton) and a polymerizable group, and has high polymerization reactivity, a wide liquid crystal phase temperature range, good miscibility, etc. When this compound (1) is mixed with other liquid crystal compounds or polymerizable compounds, it easily becomes homogeneous.

[0040] End group R of compound (1) 1a or R 1b , ring structure A 1 , A 2 or A 3 and bonding group Z 1 , Z 2 , Z 3 or Z 4 By appropriately selecting the above, physical properties such as the liquid crystal phase region can be adjusted as desired. The effects of the types of terminal group, ring structure, and bonding group on the physical properties of compound (1), as well as preferred examples thereof, are described below.

[0041] <Terminal group R 1 :R 1a and R 1b ) End group R of compound (1) 1 is a polymerizable group represented by any one of formulas (PG-1) to (PG-6). TIFF0007739863000013.tif56127 In formulas (PG-1) to (PG-6), R b is hydrogen, halogen, —CF 3 or alkyl having 1 to 5 carbon atoms, and q is 0 or 1. Also R b When there are a plurality of, they may be the same or different.

[0042] Preferred examples include polymerizable groups represented by formulae (PG-1a) to (PG-1d), (PG-2a), (PG-3a), (PG-4a), (PG-5a) to (PG-5d), and (PG-6a) to (PG-6c). TIFF0007739863000014.tif77132

[0043] Among these preferred polymerizable groups, (PG-1a) to (PG-1d), (PG-2a), and (PG-4a) have an α,β-unsaturated ketone structure, and therefore can be polymerized by various means to produce polymers with higher molecular weights. (PG-3a) has a vinyl group adjacent to an electron-donating group, and therefore can be polymerized by various means to produce polymers with higher molecular weights. (PG-5a) to (PG-6c) have a strained cyclic ether, and therefore can be polymerized by various means to produce polymers with higher molecular weights. Of these polymerizable groups, formulas (PG-1a) to (PG-1d), (PG-2a), (PG-3a), and (PG-4a) are more preferred, and formulas (PG-1a) and (PG-1b) are particularly preferred.

[0044] The polymerizable groups represented by formulae (PG-1) to (PG-6) can be appropriately selected depending on the film production conditions. For example, when a film is produced by the commonly used photocuring method, the group represented by formula (PG-1) is preferred, and an acrylic group or a methacrylic group is more preferred, from the viewpoints of high curability, solubility in solvents, and ease of handling.

[0045] <Ring structure A :A 1 , A 2 and A 3 > Preferred examples of the ring structure A of compound (1) include 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyridine-2,5-diyl, 3-fluoropyridine-2,5-diyl, pyrimidine-2,5-diyl, and pyridine-2,6-diyl. ,5-diyl, pyridazine-3,6-diyl, naphthalene-2,6-diyl, tetrahydronaphthalene-2,6-diyl, fluorene-2,7-diyl, 9-methylfluorene-2,7-diyl, 9,9-dimethylfluorene-2,7-diyl, 9-ethylfluorene-2,7-diyl, 9-fluorofluorene-2,7-diyl, 9,9-difluorofluorene-2,7-diyl, and the like. More preferred examples include 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2-methyl-1,4-phenylene, etc. Particularly preferred examples are 1,4-cyclohexylene or 1,4-phenylene.

[0046] The configuration of 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, or tetrahydronaphthalene-2,6-diyl is trans-preferred over cis-preferred. 2-Fluoro-1,4-phenylene and 3-fluoro-1,4-phenylene are structurally identical, so the latter is not shown. This rule also applies to the relationship between 2,5-difluoro-1,4-phenylene and 3,6-difluoro-1,4-phenylene.

[0047] When at least one ring in the ring structure A is 1,4-phenylene, the orientational order parameter and magnetic anisotropy are large. When at least two rings are 1,4-phenylene, the temperature range of the liquid crystal phase is wide and the clearing point is high. Preferred examples of 1,4-phenylene groups in which at least one hydrogen atom on the 1,4-phenylene ring may be replaced include fluorine, alkyl groups having 1 to 5 carbon atoms, -CF3, and -OCF3, which lower the melting point and increase the solubility. Furthermore, the molecular polarizability is reduced, resulting in a low relative permittivity. Furthermore, the molecular motion is suppressed, resulting in low dielectric loss.

[0048] When at least one ring is 1,4-cyclohexylene, the clearing point is high, the dielectric constant is very low, the dielectric loss is low, and the viscosity is small, and when at least two rings are 1,4-cyclohexylene, the clearing point is high, the dielectric constant is very low, the dielectric loss is low, and the viscosity is small. When at least one ring is a fused ring such as a naphthalene ring, a decahydronaphthalene ring, or a fluorene ring, the molecular volume is large and the relative dielectric constant is low.

[0049] <Binding group Z :Z 1 , Z 2 , Z 3 and Z 4 > Preferred examples of the bonding group Z in compound (1) include a single bond, -(CH2) a -, -O(CH2) a -, -(CH2) a O-, -O(CH2) a O-, -COO-, -OCO-, -CH=CH-COO-, -OCO-CH=CH-, -(CH2) a -COO-, -OCO-(CH2) a -, -CH=CH-, -SO2-, -OCF2-, or -CF2O-, where a is an integer of 1 to 20. More preferred examples are a single bond, -(CH2) a -, -(CH2) a O-, -O(CH2) a -, -O(CH2) a Examples include -O-, -COO-, or -OCO-. Particularly preferred examples are single bonds, -(CH2) a -, -(CH2) a O-, -O(CH2) a - or -O(CH2) aO—, where a is an integer from 1 to 22.

[0050] The bonding group Z is a single bond, -(CH2) a -, -(CH2) a O-, -O(CH2) a -, -O(CH2) a When the bonding group Z is -O-, -CF2O-, or -OCF2-, the viscosity decreases. a -, -(CH2) a O-, -O(CH2) a - or -O(CH2) a When it is O- and a is about 2 to 12, the melting point decreases, the solubility in organic solvents increases, and the molecular length increases, so the temperature range of the liquid crystal phase widens and the dielectric loss tangent is small.

[0051] When compound (1) has two rings, the viscosity is low, and when it has three or more rings, the clearing point is high. In this specification, six-membered rings and fused rings containing six-membered rings are basically considered to be rings, and for example, three-membered rings, four-membered rings, and five-membered rings alone are not considered to be rings. In addition, fused rings such as naphthalene rings, decahydronaphthalene rings, and fluorene rings are considered to be single rings.

[0052] As described above, the terminal group R 1 A compound having the desired physical properties can be obtained by appropriately selecting the types of ring structure A and bonding group Z, the number of rings, etc. Preferred examples of compound (1) include compounds represented by formulae (1-1-1) to (1-1-3), (1-2-1) to (1-2-6), and (1-3-1) to (1-3-6). TIFF0007739863000015.tif4482 TIFF0007739863000016.tif97102 TIFF0007739863000017.tif100117

[0053] In equations (1-1-1) to (1-1-3), (1-2-1) to (1-2-6), and (1-3-1) to (1-3-6), Z 1 , Z 2 , Z 3 and Z 4 are independently a single bond, -(CH2) a -, -O(CH2) a -, -(CH2) a O-, -O(CH2) a O-, -COO-, -OCO-, -CH=CH-COO-, -OCO-CH=CH-, -(CH2) a -COO-, -OCO-(CH2) a -, -CH=CH-, -SO2-, -OCF2-, or -CF2O-, where a is an integer of 1 to 20; Z in the formula 3 may be the same or different, X is fluorine or methyl; n is an integer from 0 to 4, When n is 2 or more, and when there are a plurality of X's in the formula, they may be the same or different, R 1a and R 1b are independently polymerizable groups represented by formula (PG-1), (PG-5), or (PG-6), TIFF0007739863000018.tif2684 In formulas (PG-1), (PG-5) and (PG-6), R b is hydrogen, halogen, -CF3, or alkyl having 1 to 5 carbon atoms, q is 0 or 1, and in the formula, R b When there are a plurality of, they may be the same or different.

[0054] More preferred examples of compound (1) are shown below. TIFF0007739863000019.tif110130 In equations (1-1-1a), (1-2-1a), (1-1-2a), (1-1-3a), (1-2-5a), and (1-2-6a), R b is hydrogen, fluorine, -CF3, or alkyl having 1 to 5 carbon atoms, and Z2 and Z 3 are independently a single bond, -(CH2) a -, -O(CH2) a -, -(CH2) a O-, -O(CH2) a O-, -COO-, -OCO-, -CH=CH-COO-, -OCO-CH=CH-, -(CH2) a -COO-, -OCO-(CH2) a -, -CH=CH-, -SO2-, -OCF2-, or -CF2O-, where a is an integer of 1 to 20; m is an integer from 0 to 20; M is a single bond or oxygen; X is fluorine or methyl; n is an integer from 0 to 4, When n is 2 or more, and when there are a plurality of X's in the formula, they may be the same or different, In the formula, R b When there are multiple , m, or M, they may be the same or different.

[0055] In the present invention, a "polymer obtained by polymerization of compound (1)" refers to a polymer obtained by polymerizing a monomer containing at least one compound (1). The polymer may contain at least one monomer unit derived from compound (1), and may contain two or more monomer units. That is, a polymer obtained by polymerization of compound (1) may be a polymer obtained by copolymerizing two or more compounds (1), or may be a copolymer of at least one compound (1) and at least one monomer other than compound (1). Such monomers other than compound (1) (hereinafter also referred to as "other polymerizable compounds") are not particularly limited.

[0056] <Other polymerizable compounds> The polymer obtained by polymerizing compound (1) may be copolymerized with other polymerizable compounds. Such polymerizable compounds are preferably those that do not reduce film-forming properties and mechanical strength. These polymerizable compounds are classified into compounds that do not have liquid crystallinity and compounds that do. Examples of polymerizable compounds that do not have liquid crystallinity include vinyl derivatives, styrene derivatives, (meth)acrylic acid derivatives, sorbic acid derivatives, fumaric acid derivatives, and itaconic acid derivatives. Preferred examples of these derivatives are shown below.

[0057] Preferred examples of the vinyl derivatives include vinyl chloride, vinyl fluoride, vinyl acetate, vinyl pivalate, vinyl 2,2-dimethylbutanoate, vinyl 2,2-dimethylpentanoate, vinyl 2-methyl-2-butanoate, vinyl propionate, vinyl stearate, vinyl 2-ethyl-2-methylbutanoate, N-vinylacetamide, vinyl pt-butylbenzoate, vinyl N,N-dimethylaminobenzoate, vinyl benzoate, ethyl vinyl ether, hydroxybutyl monovinyl ether, t-amyl vinyl ether, cyclohexanedimethanol methyl vinyl ether, α,β-vinylnaphthalene, methyl vinyl ketone, and isobutyl vinyl ketone.

[0058] Preferred styrene derivatives include, for example, styrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, o-chloromethylstyrene, m-chloromethylstyrene, p-chloromethylstyrene, and α-methylstyrene.

[0059] Preferred examples of the (meth)acrylic acid derivatives include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, phenyl (meth)acrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, tetraethylene glycol diacrylate, trimethylolpropane triacrylate, trimethylol EO-adduct triacrylate, pentaerythritol triacrylate, trisacryloyloxyethyl phosphate, bisphenol A EO-adduct diacrylate, bisphenol A glycidyl diacrylate (trade name: "Viscoat 700" manufactured by Osaka Organic Chemical Industry Co., Ltd.), and polyethylene glycol diacrylate dimethyl itaconate.

[0060] Preferred examples of the sorbic acid derivatives include sodium sorbate, potassium sorbate, lithium sorbate, 1-naphthylmethylammonium sorbate, benzylammonium sorbate, dodecylammonium sorbate, octadecylammonium sorbate, methyl sorbate, ethyl sorbate, propyl sorbate, isopropyl sorbate, butyl sorbate, t-butyl sorbate, hexyl sorbate, octyl sorbate, octadecyl sorbate, cyclopentyl sorbate, cyclohexyl sorbate, vinyl sorbate, allyl sorbate, and propargyl sorbate.

[0061] Preferred fumaric acid derivatives include, for example, dimethyl fumarate, diethyl fumarate, diisopropyl fumarate, dibutyl fumarate, dicyclopentyl fumarate, and dicyclohexyl fumarate.

[0062] Preferred itaconic acid derivatives include, for example, diethyl itaconate, dibutyl itaconate, and diisopropyl itaconate. In addition to these, many polymerizable compounds such as butadiene, isoprene, and maleimide can also be used.

[0063] <Other polymerizable liquid crystal compounds> The composition (1) for low dielectric substrates may contain a polymer obtained by polymerizing a polymerizable liquid crystal compound other than the polymer made of compound (1). From the viewpoint of compatibility with compound (1) and organic solvents, the compounds represented by formula (M1), (M2), or (M3) are preferred as the polymerizable liquid crystal compound.

[0064] TIFF0007739863000020.tif62123

[0065] In formulas (M1), (M2), and (M3), A M are independently any divalent group selected from 1,4-phenylene, 1,4-cyclohexylene, 1,4-cyclohexenylene, pyridine-2,5-diyl, 1,3-dioxane-2,5-diyl, naphthalene-2,6-diyl, and fluorene-2,7-diyl, in which at least one hydrogen may be replaced by fluorine, chlorine, cyano, hydroxy, formyl, trifluoroacetyl, difluoromethyl, trifluoromethyl, alkyl having 1 to 5 carbon atoms, alkoxy having 1 to 5 carbon atoms, alkoxycarbonyl having 1 to 5 carbon atoms, or alkanoyl having 1 to 5 carbon atoms; Z Mare independently a single bond, -OCH2-, -CHO-, -COO-, -OCO-, -COS-, -SCO-, -OCOO-, -CONH-, -NHCO-, -CF2O-, -OCF2-, -CH2CH2-, -CF2CF2-, -CH=CHCOO-, -OCOCH=CH-, -CH2CH2COO-, -OCOCH2CH2-, -COOCH2CH2-, -CH2CHOCO-, -CH=CH-, -N=CH-, -CH=N-, -N=C(CH3)-, -C(CH3)=N-, -N=N-, -C≡C-, -CH=NN=CH-, or -C(CH3)=NN=C(CH3)-; X M is hydrogen, fluorine, chlorine, trifluoromethyl, trifluoromethoxy, cyano, alkyl having 1 to 20 carbon atoms, alkenyl having 1 to 20 carbon atoms, alkoxy having 1 to 20 carbon atoms, or alkoxycarbonyl having 1 to 20 carbon atoms, Y M are independently a single bond, -O-, -COO-, -OCO-, or -OCOO-, Q M is a single bond, -O-, -COO-, or -OCO-, q is an integer from 1 to 6; c and d are independently integers of 0 to 3 and satisfy the relationship 1≦c+d≦6, and a is an integer of 0 to 20; R M is hydrogen or methyl.

[0066] The polymer obtained by polymerizing compound (1) can be used as a prepolymer for low-dielectric substrates. A prepolymer is an intermediate product obtained by stopping the polymerization reaction of a monomer midway, and is the pre-polymer stage. By heating this prepolymer, polymerization and crosslinking reactions can be easily induced.

[0067] The number-average molecular weight (Mn) of the polymer obtained by polymerizing compound (1) is not particularly limited, but is preferably 300,000 or less, more preferably 150,000 or less, even more preferably 50,000 or less, even more preferably 30,000 or less, even more preferably 10,000 or less, and particularly preferably 6,000 or less. When the polymer is used as a prepolymer for a low-dielectric substrate, a number-average molecular weight (Mn) of preferably 300,000 or less provides an appropriate melt viscosity and therefore excellent moldability. When the polymer is used as a prepolymer, residual monomers may be present, and monomers may coexist in the composition.

[0068] The molecular weight of the polymer obtained by polymerizing compound (1) was measured using gel permeation chromatography (GPC) "Nexera GPC System" (a testing device manufactured by Shimadzu Corporation) using tetrahydrofuran or dimethyl sulfoxide (containing lithium bromide as an additive) as a carrier and polystyrene or pullulan as a molecular weight standard.

[0069] Polymers obtained by polymerizing compound (1) of the present invention can be produced by polymerizing the monomer compound (1) using conventional methods such as radical polymerization, anionic polymerization, and cationic polymerization. For example, they can be produced by the method described in "Experimental Chemistry Lectures, Vol. 28, Polymer Synthesis, 4th Edition" (edited by the Chemical Society of Japan). Regarding the method for producing the polymer of the present invention, when the polymerizable group is (PG-1), (PG-2), or (PG-4), radical polymerization, which allows for appropriate control of the weight-average molecular weight, is preferred. When the polymerizable group is (PG-3), cationic polymerization or radical polymerization via copolymerization with other radically polymerizable monomers is preferred. When the polymerizable group is (PG-5) or (PG-6), cationic polymerization, which has good reactivity, is desirable. Furthermore, when the polymerizable group is (PG-5) or (PG-6), polymers can also be produced by polyaddition reaction with amine-based curing agents, acid anhydride-based curing agents, or phenol-based curing agents.

[0070] Examples of solvents for radical polymerization reactions include ethers, esters, ketones, amides, sulfoxides, alcohols, and hydrocarbons. More specifically, ethers include chain ethers such as diethyl ether, and cyclic ethers such as tetrahydrofuran and dioxane. Esters include methyl acetate, ethyl acetate, butyl acetate, and ethyl lactate. Ketones include acetone, methyl ethyl ketone, and methyl isobutyl ketone. Amides include N,N-dimethylacetamide and N,N-dimethylformamide. Sulfoxides include dimethyl sulfoxide. Alcohols include methanol, ethanol, and propanol. Hydrocarbons include aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as hexane, and alicyclic hydrocarbons such as cyclohexane.

[0071] As the solvent for the radical polymerization reaction, a mixed solvent obtained by mixing the solvents for the polymerization reaction described above may be used. As the polymerization initiator, a known polymerization initiator may be used. The temperature for the polymerization reaction may be appropriately selected within the range of, for example, about 30 to 150°C.

[0072] In the radical polymerization method for producing a polymer obtained by polymerizing compound (1) of the present invention, preferred polymerization initiators include organic azo polymerization initiators such as 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis[N-(2-propyl)-2-methylpropionamide], and 2,2-azobis[2-(2-imidazolin-2-yl)propane], as well as organic peroxides such as benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, and t-butylperoxybenzoate. These polymerization initiators may be used alone or in combination.

[0073] In the method for producing a polymer obtained by polymerizing compound (1) of the present invention by radical polymerization, an organic azo polymerization initiator such as 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, or 2,2'-azobis(2-methylbutyronitrile) can be preferably used. The use of an organic azo polymerization initiator ensures safety during polymer production, and tends to produce a polymer with a controlled weight-average molecular weight.

[0074] In the method for producing a polymer obtained by polymerizing compound (1) of the present invention by radical polymerization, it is desirable to use 0.5 to 100 parts by weight, preferably 2 to 50 parts by weight, more preferably 5 to 30 parts by weight of a polymerization initiator per 100 parts by weight of monomer, in order to appropriately control the weight-average molecular weight.

[0075] In the method for producing a polymer obtained by polymerizing compound (1) of the present invention by radical polymerization, a chain transfer agent can be used as needed. The chain transfer agent is not particularly limited, but a mercaptan compound can be preferably used to control the weight-average molecular weight of the polymer and to improve the adhesion of the resin to copper foil, etc. Examples of mercaptan compounds include primary, secondary, and tertiary mercaptans having an alkyl group or a substituted alkyl group, such as n-butyl, isobutyl, n-octyl, n-dodecyl, sec-butyl, sec-dodecyl, and tert-butyl mercaptan; aromatic mercaptans such as phenyl mercaptan, thiocresol, and 4-tert-butyl-o-thiocresol; mercaptan compounds containing a carboxy group, such as mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, and mercaptosuccinic acid; mercaptan compounds containing an ester group, such as ethyl mercaptoacetate, cyclohexyl 3-mercaptopropionate, and tridecyl 3-mercaptopropionate; and mercaptan compounds containing a hydroxyl group, such as 2-mercaptoethanol and 3-mercapto-1,2-propanediol. These compounds can be used alone or in combination of two or more. Among these mercaptan compounds, mercaptan compounds containing a carboxy group, such as mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, and mercaptosuccinic acid, are more preferred in order to improve the adhesion of the resin to copper foil, etc. It is also desirable to use 0.5 to 200 parts by weight, preferably 5 to 100 parts by weight, and more preferably 30 to 100 parts by weight of a chain transfer agent per 100 parts by weight of the above-mentioned monomer.

[0076] [Method for synthesizing compound (1)] Compound (1) can be synthesized by combining known techniques in organic synthetic chemistry. Methods for introducing desired terminal groups, ring structures, and bonding groups into starting materials are described in, for example, Houben-Wyle, Methods of Organic Chemistry (Georg Thieme Verlag, Stuttgart), Organic Syntheses (John Wily & Sons, Inc.), Organic Reactions (John Wily & Sons, Inc.), Comprehensive Organic Synthesis (Pergamon Press), and New Experimental Chemistry Lectures (Maruzen).

[0077] The method for introducing the bonding group Z is explained in the following schemes 1 to 9. In these schemes, MSG 1 and MSG 2 represents a monovalent organic group having at least one ring, and Hal represents a halogen. 1 (or MSG 2 ) may be the same or different. Compounds (1A) to (1M) in the following scheme correspond to the above-mentioned compound (1). These methods can be applied to the synthesis of optically active compound (1) and optically inactive compound (1).

[0078] (Scheme 1) Compounds where Z is a single bond As shown below, MSG can be obtained by reacting an arylboronic acid (S1) with a compound (S2) synthesized by a known method in the presence of an aqueous carbonate solution and a catalyst such as tetrakis(triphenylphosphine)palladium. 1 and MSG 2Compound (1A) can be synthesized in which a single bond is introduced between Compound (1A). Compound (1A) can also be synthesized by reacting Compound (S3), which is synthesized by a known method, with n-butyllithium and then zinc chloride, and then further reacting it with Compound (S2) in the presence of a catalyst such as dichlorobis(triphenylphosphine)palladium.

[0079] TIFF0007739863000021.tif52137

[0080] (Scheme 2) Compounds where Z is -CH=CH- As shown below, MSG can be obtained by reacting a phosphorus ylide generated by reacting a phosphonium salt (S5) synthesized by a known method with a base such as potassium t-butoxide with an aldehyde (S4). 1 and MSG 2 Compound (1B) can be synthesized in which -CH=CH- is introduced between the two. Depending on the reaction conditions and substrate, a cis isomer may be produced, and if necessary, the cis isomer can be isomerized to a trans isomer by a known method.

[0081] TIFF0007739863000022.tif33122

[0082] (Scheme 3) Compounds where Z is -(CH2)2- As shown below, the compound (1B) obtained as above is hydrogenated in the presence of a catalyst such as palladium on carbon to give MSG. 1 and MSG 2 Compound (1C) having -(CH2)2- between the two can be synthesized.

[0083] TIFF0007739863000023.tif25130

[0084] (Scheme 4) Compounds where Z is -(CF2)2- As shown below, MSG can be obtained by fluorinating diketone (S6) with sulfur tetrafluoride in the presence of hydrogen fluoride catalyst according to the method described in J. Am. Chem. Soc., 2001, 123, 5414. 1 and MSG 2 Compound (1D) having -(CF2)2- between the two can be synthesized.

[0085] TIFF0007739863000024.tif35122

[0086] (Scheme 5) Compounds where Z is -(CH2)4- As shown below, a compound having -(CH2)2-CH=CH- was synthesized by using phosphonium salt (S7) instead of phosphonium salt (S5) according to the method of Scheme 2, and this was catalytically hydrogenated in the same manner as in Scheme 3 to obtain MSG. 1 and MSG 2 Compound (1E) can be synthesized in which -(CH2)4- is introduced between the

[0087] TIFF0007739863000025.tif34151

[0088] (Scheme 6) Compounds where Z is -CH2O- or -OCH2- As shown below, compound (S4) is reduced with a reducing agent such as sodium borohydride to obtain compound (S8). This is then halogenated with hydrobromic acid or the like to obtain compound (S9). Compound (S9) is reacted with compound (S10) in the presence of potassium carbonate or the like to obtain MSG. 1 and MSG 2 Compound (1F) can be synthesized in which -OCH2- (or -CH2O-) is introduced between

[0089] TIFF0007739863000026.tif55147

[0090] (Scheme 7) Compounds in which Z is -COO- or -OCO- As shown below, compound (S3) is reacted with n-butyllithium and then carbon dioxide to obtain carboxylic acid (S11). Compound (S11) is then dehydrated with phenol (S10) in the presence of DCC (1,3-dicyclohexylcarbodiimide) and DMAP (4-dimethylaminopyridine) to obtain MSG. 1 and MSG 2 Compound (1G) can be synthesized in which -COO- (or -OCO-) is introduced between

[0091] TIFF0007739863000027.tif34151

[0092] (Scheme 8) Compounds where Z is -CF=CF- As shown below, compound (S3) is treated with n-butyllithium and then reacted with tetrafluoroethylene to obtain compound (S12). Next, compound (S2) is treated with n-butyllithium and then reacted with compound (S12) to obtain MSG. 1 and MSG 2 It is possible to synthesize compound (1H) in which -CF=CF- is introduced between the two. By selecting the synthesis conditions, it is also possible to produce a cis compound.

[0093] TIFF0007739863000028.tif37146

[0094] (Scheme 9) Compounds where Z is -CF2O- or -OCF2- As shown below, compound (1G) obtained by a method such as Scheme 7 above is treated with a sulfurizing agent such as Lawesson's reagent to obtain compound (S16). Compound (S16) is fluorinated with a hydrogen fluoride pyridine complex and N-bromosuccinimide (NBS) to obtain MSG. 1 and MSG 2Compound (1M) can be synthesized by fluorinating compound (S16) with (diethylamino)sulfur trifluoride (DAST). These bonding groups can also be generated by the method described in P. Kirsch et al., Angew. Chem. Int. Ed. 2001, 40, 1480.

[0095] TIFF0007739863000029.tif55119

[0096] [Liquid Crystal Composition] The composition (1) for low dielectric substrates in the present invention may contain at least one polymer obtained by polymerizing compound (1), and may also contain a polymer obtained by polymerizing two or more compounds. That is, the composition (1) for low dielectric substrates may be composed of a polymer consisting of two or more compounds (1), or may be composed of a combination of a polymer consisting of at least one compound (1) and at least one compound other than compound (1). Such components other than compound (1) are not particularly limited, and examples thereof include polymerizable compounds other than compound (1) (hereinafter also referred to as "other polymerizable compounds"), non-polymerizable liquid crystal compounds, optically active compounds, polymerization initiators, solvents, and fillers.

[0097] <Other polymerizable compounds> The composition (1) for low dielectric substrates may contain other polymerizable compounds as constituent elements. Such polymerizable compounds are preferably compounds that do not reduce film-forming properties and mechanical strength. These polymerizable compounds are classified into compounds that do not have liquid crystallinity and compounds that do. Examples of polymerizable compounds that do not have liquid crystallinity include vinyl derivatives, styrene derivatives, (meth)acrylic acid derivatives, sorbic acid derivatives, fumaric acid derivatives, and itaconic acid derivatives. Preferred examples of these derivatives are the same as those described above for the polymer obtained by polymerizing compound (1).

[0098] <Other polymerizable liquid crystal compounds> The composition (1) for low dielectric substrates may contain a polymer obtained by polymerizing a polymerizable liquid crystal compound other than the polymer made of compound (1). From the viewpoints of the development of a liquid crystal phase in the polymerizable liquid crystal composition and the compatibility with compound (1) and organic solvents, the compounds represented by the above formula (M1), (M2), or (M3) are preferred as the polymerizable liquid crystal compound.

[0099] <Non-polymerizable liquid crystal compounds> The composition (1) for low dielectric substrates may contain a liquid crystal compound that does not have a polymerizable group as a constituent element. Examples of such non-polymerizable liquid crystal compounds are described in LiqCryst (LCI Publisher GmbH, Hamburg, Germany), a database of liquid crystal compounds. Polymerization of the composition (1) for low dielectric substrates containing a non-polymerizable liquid crystal compound can produce composite materials containing a polymer of compound (1) and a liquid crystal compound. In such composite materials, the non-polymerizable liquid crystal compound exists in a polymer network, such as a polymer-dispersed liquid crystal.

[0100] <Polymerization initiator> The composition for low dielectric substrates (1) may contain a polymerization initiator as a constituent element. The polymerization initiator may be, for example, a photoradical polymerization initiator, a photocationic polymerization initiator, or a thermal radical polymerization initiator, depending on the polymerization method of the composition for low dielectric substrates (1).

[0101] The photoradical polymerization initiator is not particularly limited, and known initiators can be used. For example, 4-methoxyphenyl-2,4-bis(trichloromethyl)triazine, 2-(4-butoxystyryl)-5-trichloromethyl-1,3,4-oxadiazole, 9-phenylacridine, 9,10-benzphenazine, benzophenone / Michler's ketone mixture, hexaarylbiimidazole / mercaptobenzimidazole mixture, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, benzil dimethyl ketal, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2,4-diethylxanthone / methyl p-dimethylaminobenzoate mixture, benzophenone / methyltriethanolamine mixture, and the like can be mentioned. Examples of commercially available products include "Darocur Series 1173, 4265" and "Irgacure Series 184, 369, 500, 651, 784, 819, 907, 1300, 1700, 1800, 1850, 2959" manufactured by Chiba Specialty Co., Ltd.

[0102] The photocationic polymerization initiator is not particularly limited, and known initiators can be used, such as "Sylacure UVI-6990, 6974" manufactured by UCC Corporation, "Adeka Optomer SP-150, 152, 170, 172" manufactured by Asahi Denka Co., Ltd., "Photoinitiator 2074" manufactured by Rhodia Corporation, "Irgacure 250" manufactured by Chiba Specialty Co., Ltd., and "DTS-102" manufactured by Midori Chemical Co., Ltd.

[0103] Preferred initiators for thermal radical polymerization include, for example, benzoyl peroxide, diisopropyl peroxydicarbonate, t-butylperoxy-2-ethylhexanoate, t-butyl peroxypivalate, di-t-butyl peroxide (DTBPO), t-butyl peroxydiisobutyrate, lauroyl peroxide, dimethyl 2,2′-azobisisobutyrate (MAIB), azobisisobutyronitrile (AIBN), azobiscyclohexanecarbonitrile (ACN), and the like.

[0104] Preferred initiators for anionic polymerization, coordination polymerization and living polymerization include, for example, alkali metal alkyl compounds such as n-C4H9Li and t-C4H9Li-R3Al, aluminum compounds, transition metal compounds and the like.

[0105] <Curing agent> When the composition for low dielectric substrates (1) contains a compound having a cyclic ether group as a constituent element, it may contain a curing agent as a constituent element. Preferred examples of the curing agent are shown below.

[0106] Amine curing agents include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, o-xylenediamine, m-xylenediamine, p-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, diethylaminopropylamine, isophoronediamine, 1,3-bisaminomethylcyclohexane, bis(4-amino-3-methylcyclohexyl)methane, bis(4-aminocyclohexyl)methane, norbornene diamine, 1,2 -diaminocyclohexane, 3,9-dipropanamine-2,4,8,10-tetraoxaspiro[5,5]undecane, 4,4'-diaminodiphenylmethane, 4,4'-diamino-1,2-diphenylethane, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylsulfone, polyoxypropylenediamine, polyoxypropylenetriamine, polycyclohexylpolyamine, N-aminoethylpiperazine, and the like.

[0107] Examples of acid anhydride curing agents include tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexenetetracarboxylic dianhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, ethylene glycol bisanhydrotrimethylate, glycerin bis(anhydrotrimellitate) monoacetate, dedecenylsuccinic anhydride, and chlorendic anhydride.

[0108] Examples of phenol-based curing agents include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, m-ethylphenol, p-ethylphenol, 2,3,5-trimethylphenol, 2,3,6-trimethylphenol, o-isopropylphenol, p-tert-butylphenol, o-sec-butylphenol, p-octylphenol, 2,6-di-tert-butylphenol, resorcinol, 1-naphthol, 2-naphthol, bisphenol A, phenol novolac, xylylene novolac, and bisphenol A novolac. In addition to the above, curing agents described in JP-A Nos. 2004-256687 and 2002-226550 can also be used.

[0109] <Inorganic filler as a filling material> A filler (inorganic filler) can be added to the low-dielectric substrate composition (1) to improve mechanical strength, reduce dielectric loss, improve thermal conductivity, adjust viscosity, and so on. For example, adding silica powder, particularly hollow silica powder, can produce a cured product with a low dielectric tangent. Furthermore, adding metal fillers such as metal nitrides (e.g., aluminum nitride, boron nitride, and silicon nitride); carbides (e.g., diamond, graphite, and silicon carbide); metal oxides (e.g., magnesium oxide, aluminum oxide, zinc oxide, titanium oxide, tin oxide, holmium oxide, and calcium oxide); metal hydroxides (e.g., magnesium hydroxide and aluminum hydroxide); silicate compounds (e.g., cordierite and mullite); and metal fillers (e.g., gold, silver, copper, platinum, iron, tin, lead, nickel, aluminum, magnesium, tungsten, molybdenum, and stainless steel) can improve thermal conductivity. Hollow silica and boron nitride, which have low dielectric constants, are preferred. The more inorganic filler there is, the higher the thermal conductivity etc., but since inorganic fillers generally have a higher relative dielectric constant and a smaller dielectric loss tangent than resin components, increasing the filling amount increases the dielectric constant. Therefore, it is preferable to fill the required amount within a range that does not exceed the desired dielectric constant.

[0110] Examples of the shape of the filler include spherical, amorphous, fibrous, rod-like, cylindrical, and plate-like. The shape of the filler is preferably one that does not interfere with the orientation of the polymerizable liquid crystal compound when it develops a liquid crystal phase. The type, shape, size, and amount of the filler can be appropriately selected depending on the purpose. If the resulting low-dielectric-constant molded product requires insulation, a conductive filler may be used as long as the desired insulation, dielectric constant, and dielectric loss are maintained. Preferably, hollow silica is used to obtain a cured product with low dielectric constant and low dielectric loss tangent. Plate-shaped crystalline boron nitride has a low dielectric constant, so it can achieve both high thermal conductivity and low dielectric properties. The use of polymerizable liquid crystal compounds and fine-grained spherical silicon oxide can increase the viscosity of the melt or solution, while the use of silicate compounds is preferred because it can reduce the thermal expansion coefficient of the molded product.

[0111] The average particle size of spherical or irregularly shaped fillers is preferably 0.1 to 200 μm. More preferably, it is 1 to 100 μm. A diameter of 0.1 μm or greater improves thermal conductivity, while a diameter of 200 μm or less allows for increased filling rate. Regarding fibrous fillers, longer fiber lengths improve tensile strength, but also make kneading and dispersion more difficult, so selection is recommended based on the application. For dispersion, whisker-like short fibers are preferred because they facilitate uniform dispersion and improve the strength of low-dielectric-constant molded bodies. Note that the average particle size in this specification is based on particle size distribution measured using laser diffraction and scattering methods. Specifically, using analysis based on the Fraunhofer diffraction theory and Mie scattering theory, a powder is divided into two particles at a certain particle size using a wet method. The median diameter is the diameter at which the larger and smaller particles are equal in volume. The amount of filler is preferably 20 to 95% by weight in the cured low dielectric constant molded body. More preferably, it is 50 to 95% by weight. If it is 20% by weight or more, the thermal conductivity becomes high, which is preferable. If it is 95% by weight or less, the low dielectric constant molded body does not become brittle, which is preferable. As the filler, commercially available products that have been surface-treated, such as by dispersion treatment or waterproofing treatment, may be used as they are, or the commercially available products from which the surface treatment agents have been removed may be used. Alternatively, untreated fillers may be used after being treated with a silane coupling agent, affinity agent, surface tension adjuster, anti-settling agent, anti-aggregation agent, etc.

[0112] <Glass cloth> The low-dielectric substrate composition (1) may be combined with glass cloth and cured to achieve excellent mechanical strength, dielectric properties, thermal conductivity, etc. Commercially available glass cloth can be used, and low-dielectric glass cloth is preferred because it can achieve mechanical strength and dielectric properties suitable for printed circuit boards used at high frequencies. Surface-treated glass cloth can also be used to enhance compatibility with the low-dielectric substrate composition (1). It is preferable to use glass cloth with fiber thickness and density that meets the physical properties required for the intended substrate. Impregnating the cloth with a solution of a polymer dissolved in a solvent, evaporating the solvent, and then heating under pressure can produce a substrate with smoothness and mechanical strength suitable for printed circuit boards.

[0113] <Solvent> The composition (1) for low dielectric substrates may contain a solvent. Polymerization of the composition (1) for low dielectric substrates may be carried out in a solvent or without a solvent. The solvent-containing composition (1) for low dielectric substrates may be applied to a substrate by, for example, spin coating, and then photopolymerized after removing the solvent. After photocuring, the composition may be post-treated by heating to an appropriate temperature and thermal curing.

[0114] Preferred solvents include, for example, benzene, toluene, xylene, mesitylene, hexane, heptane, octane, nonane, decane, tetrahydrofuran, γ-butyrolactone, N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, cyclohexane, methylcyclohexane, cyclopentanone, cyclohexanone, PGMEA, etc. The above solvents may be used alone or in combination of two or more. It is not particularly meaningful to limit the proportion of the solvent used during polymerization, and the proportion may be determined for each individual case, taking into consideration the polymerization efficiency, solvent cost, energy cost, etc.

[0115] <Other additives> The low dielectric substrate composition (1), which includes compound (1), a polymer obtained by polymerizing compound (1), and polymer (1) obtained by polymerizing compound (1), is polymerizable, and therefore a stabilizer may be added to facilitate handling. Since polymer (1) has residual polymerizable groups, it is used as a prepolymer. Known stabilizers can be used without limitation, and examples include hydroquinone, 4-ethoxyphenol, and 3,5-di-t-butyl-4-hydroxytoluene (BHT). In applications requiring a low dielectric tangent (low tanδ) and a high glass transition temperature, it is preferable to add a crosslinking agent. The crosslinking agent preferably forms a chemical bond with the polymerizable group of the liquid crystal compound having a polymerizable group at its terminal, thereby forming a three-dimensional crosslink.

[0116] [Low dielectric constant resin] The low dielectric constant resin, which is another embodiment of the present invention, is a cured product of the above-mentioned composition for low dielectric substrates, and is used for sheet-like, film-like, plate-like, fibrous, and three-dimensionally shaped parts (insulating parts of connectors), etc., and can also be used as a coating agent, adhesive, or filler as it is. Because the low dielectric constant resin is a cured product of the above-mentioned composition, it has a low dielectric constant, and because it uses a polymerizable liquid crystal compound as the polymer, it also has excellent thermal conductivity, heat resistance, rigidity, elasticity, molding flowability, chemical resistance, dimensional stability, and the like.

[0117] When a low-dielectric resin exhibits liquid crystallinity, the molecular orientation can be controlled by an orientation process before curing. The relative dielectric constant and thermal conductivity exhibit anisotropy depending on the molecular orientation direction. For example, when designing the dielectric constant and thermal design of an electronic substrate, more advanced material design becomes possible, such as designing the area directly below the IC that generates heat to have high thermal conductivity in the thickness direction, and orienting the area other than directly below the IC in the horizontal direction to spread the heat over a wide area. The orientation method can be controlled using the following methods.

[0118] Methods for controlling the alignment of the mesogenic portion of liquid crystal molecules in a composition for low-dielectric substrates include treating the filler surface with a silane coupling agent or alignment agent that has alignment ability, and aligning the molecules using the self-alignment force of the composition itself. These methods may be used alone or in combination. Examples of alignment states controlled by such alignment control methods include homogeneous, twisted, homeotropic, hybrid, bend, and spray alignment, and can be selected appropriately depending on the application and alignment control method. Furthermore, during film formation or molding, physical alignment can also be achieved by applying shear stress to the liquid crystal state before curing.

[0119] The orientation temperature is in the range of room temperature to 250°C, preferably room temperature to 200°C, and more preferably room temperature to 180°C. The heat treatment time is in the range of 5 seconds to 2 hours, preferably 10 seconds to 60 minutes, and more preferably 20 seconds to 30 minutes. If the heat treatment time is shorter than the above range, the temperature of the layer composed of the low dielectric substrate composition (1) may not be raised to the predetermined temperature, while if it is longer than the above range, productivity may decrease. Note that the above heat treatment conditions vary depending on the type and compositional ratio of the compounds used in the low dielectric substrate composition (1), the presence and content of a polymerization initiator, etc., and therefore only indicate approximate ranges. In particular, if the temperature is higher than the polymerization initiation temperature, the resin will harden before orientation occurs, making it impossible to obtain a low dielectric constant resin with molecular chains oriented in a specific direction.

[0120] Polymerization methods for the composition (1) for low dielectric substrates include, for example, radical polymerization, anionic polymerization, cationic polymerization, and coordination polymerization. However, to fix the molecular arrangement or helical structure, thermal polymerization or photopolymerization using light or heat, such as electron beams, ultraviolet rays, visible light, or infrared rays (heat rays), is suitable. Thermal polymerization is preferably carried out in the presence of a radical polymerization initiator, and photopolymerization is preferably carried out in the presence of a photoradical polymerization initiator. For example, a polymer in which the arrangement of liquid crystal molecules is fixed can be obtained by a polymerization method involving irradiation with ultraviolet rays or an electron beam in the presence of a photoradical polymerization initiator. The resulting polymer (1) may be a homopolymer, random copolymer, alternating copolymer, block copolymer, or graft copolymer, and the method can be selected appropriately depending on the application.

[0121] When the orientation of the composition (1) for low dielectric substrates is fixed by photopolymerization, ultraviolet or visible light is usually used. The wavelength of the light used for light irradiation is in the range of 150 to 500 nm, preferably 250 to 450 nm, and more preferably 300 to 400 nm. Examples of light sources for light irradiation include low-pressure mercury lamps (germicidal lamps, fluorescent chemical lamps, black lights), high-pressure discharge lamps (high-pressure mercury lamps, metal halide lamps), short-arc discharge lamps (ultra-high-pressure mercury lamps, xenon lamps, mercury-xenon lamps), and ultraviolet light-emitting diodes. Among these, metal halide lamps, xenon lamps, ultraviolet light-emitting diodes, and high-pressure mercury lamps are preferred.

[0122] The wavelength range of the irradiation light source may be selected by placing a filter or the like between the light source and the composition for low dielectric substrates (1) to allow only a specific wavelength range to pass through. The amount of light irradiated from the light source is 2 to 5000 mJ / cm. 2 , preferably 10 to 3000 mJ / cm 2 , more preferably 100 to 2000 mJ / cm 2 The temperature conditions during light irradiation are preferably set to the same range as the heat treatment temperature described above.

[0123] Conditions for fixing the orientation of the composition (1) for low dielectric substrates by thermal polymerization include a thermosetting temperature in the range of room temperature to 350°C, preferably room temperature to 250°C, and more preferably 50°C to 200°C, and a curing time in the range of 5 seconds to 10 hours, preferably 1 minute to 5 hours, and more preferably 5 minutes to 1 hour. After polymerization, it is preferable to slowly cool the composition to suppress stress distortion. Furthermore, a reheating treatment may be performed to relieve distortion.

[0124] The orientation-controlled polymer or the polymer in the polymerization process may be further oriented in any direction by a mechanical operation such as stretching. The isolated polymer (1) may be dissolved in a solvent and oriented on an alignment-treated substrate to form a film, or two polymers may be mixed and processed, or multiple polymers may be laminated. Examples of suitable solvents include N-methyl-2-pyrrolidone, dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide, N,N-dimethylacetamide dimethyl acetal, tetrahydrofuran, chloroform, 1,4-dioxane, bis(methoxyethyl)ether, γ-butyrolactone, tetramethylurea, trifluoroacetic acid, ethyl trifluoroacetate, hexafluoro-2-propanol, 2-methoxyethyl acetate, methyl ethyl ketone, cyclopentanone, and cyclohexanone. These solvents may also be mixed with common organic solvents such as acetone, benzene, toluene, heptane, and methylene chloride.

[0125] Even if a highly linear low-dielectric substrate composition does not exhibit liquid crystallinity or exhibits a very narrow range of liquid crystal phase, if it has high crystallinity, it will form domains with axes aligned in a certain direction, resulting in higher thermal conductivity than polymerizable compounds such as bisphenol A structures. Orientation and crystallinity can also be controlled by slowly curing the composition from an isotropic liquid state with the surface of a polymer sheet with aligned orientation or a crystalline resin filler present as a core for crystal growth. However, excessive crystallinity tends to reduce flexibility, so it is necessary to use a polymerizable composition with appropriate crystallinity.

[0126] The low dielectric constant molded article of the present invention is made of the low dielectric substrate composition (1) and is used in the form of a sheet, film, thin film, fiber, molded article, or the like. Preferred forms are films and thin films. Films and thin films can be obtained by polymerizing the low dielectric substrate composition (1) in a state where it is applied to a substrate or a release film, or sandwiched between flat plates such as a substrate or a mold. Alternatively, the low dielectric substrate composition (1) containing a solvent can be applied to an orientation-treated substrate and the solvent removed. Furthermore, films can also be obtained by press-molding the polymer. In this specification, the thickness of the sheet is 1 mm or more, the thickness of the film is 5 μm or more, preferably 10 to 500 μm, and more preferably 20 to 300 μm, and the thickness of the thin film is less than 5 μm.

[0127] Hereinafter, a method for producing a film, which is a low dielectric constant molded article, using the solvent-containing composition for low dielectric substrates (1) will be specifically described. First, the composition (1) for low dielectric substrates is applied to a substrate that has been subjected to a release treatment, and the solvent is then dried to remove the composition, thereby forming a coating layer with a uniform thickness. Examples of the application method include spin coating, roll coating, caten coating, flow coating, printing, microgravure coating, gravure coating, wire bar coding, dip coating, spray coating, and meniscus coating.

[0128] The solvent can be removed by drying, for example, air drying at room temperature, drying on a hot plate, drying in a drying oven, or blowing warm or hot air. The conditions for solvent removal are not particularly limited; drying can be performed until the solvent is mostly removed and the coating layer loses its fluidity. Depending on the type and composition of the compounds used in the low-dielectric substrate composition (1), the molecular orientation of the liquid crystal molecules in the coating layer may be completed during the drying process. In such cases, the coating layer that has undergone the drying process can be subjected to the polymerization process without undergoing the heat treatment process described above. However, to achieve a more uniform orientation of the liquid crystal molecules in the coating layer, it is preferable to heat the coating layer that has undergone the drying process to a liquid crystal phase expression temperature to align them in the liquid crystal state, and then fix the orientation by photopolymerization or thermal polymerization.

[0129] Furthermore, when the low-dielectric substrate composition (1) is cured and used as a low-dielectric-constant insulating film, it is also preferable to perform an alignment treatment on the substrate surface before applying the low-dielectric substrate composition (1) to the substrate. High-molecular-weight prepolymers are difficult to align with an alignment agent, but if unreacted monomers remain or if monomers are added later, these monomers can be aligned by the alignment treatment. Alignment methods include, for example, simply forming an alignment film on the substrate, forming an alignment film on the substrate and then rubbing the film with a rayon cloth, directly rubbing the substrate with a rayon cloth, oblique deposition of silicon oxide, and rubbing-free alignment using a stretched film, a photoalignment film, or an ion beam. In some cases, the desired alignment state can be achieved without surface treatment of the substrate. For example, to achieve homeotropic alignment, surface treatments such as rubbing are often not performed, but rubbing may be performed to achieve higher alignment.

[0130] The alignment film is not particularly limited as long as it can control the alignment of the composition (1) for low dielectric substrates, and known alignment films can be used, such as polyimide, polyamide, polyvinyl alcohol, alkylsilane, alkylamine, or lecithin-based alignment films. For vertical alignment, silane coupling agents are also suitable.

[0131] Any method can be used for the rubbing treatment. Usually, a method is used in which a rubbing cloth made of a material such as rayon, cotton, or polyamide is wrapped around a metal roll or the like, and the roll is moved while rotating in contact with the substrate or the alignment film, or a method is used in which the substrate side is moved while the roll is fixed.

[0132] In order to obtain a more uniform alignment, an alignment control additive may be contained in the composition (1) for low dielectric substrates. Examples of such alignment control additives include imidazoline, quaternary ammonium salts, alkylamine oxides, polyamine derivatives, polyoxyethylene-polyoxypropylene condensates, polyethylene glycol and its esters, sodium lauryl sulfate, ammonium lauryl sulfate, lauryl amine sulfates, alkyl-substituted aromatic sulfonates, alkyl phosphates, aliphatic or aromatic sulfonic acid formalin condensates, lauryl amidopropyl betaine, lauryl aminoacetic acid betaine, polyethylene glycol fatty acid esters, polyoxyethylene alkylamines, perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkylethylene oxide adducts, perfluoroalkyltrimethylammonium salts, oligomers having a perfluoroalkyl group and a hydrophilic group, oligomers having a perfluoroalkyl group and a lipophilic group, urethanes having a perfluoroalkyl group, and organosilicon compounds having a primary amino group (for example, alkoxysilane-type, linear siloxane-type, and three-dimensionally condensed silsesquioxane-type organosilicon compounds).

[0133] Examples of the substrate include plastic film substrates such as polyimide, polyamideimide, polyamide, polyetherimide, polyetheretherketone, polyetherketone, polyketone sulfide, polyethersulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyacetal, polycarbonate, polyarylate, acrylic resin, polyvinyl alcohol, polypropylene, cellulose, triacetyl cellulose or a partially saponified product thereof, epoxy resin, phenol resin, and norbornene resin, and glass-reinforced resin substrates, as well as glass substrates such as alkali glass, borosilicate glass, and flint glass; metal substrates such as aluminum, iron, and copper; and inorganic substrates such as silicon.

[0134] The film substrate may be a uniaxially stretched film or a biaxially stretched film. The film substrate may be previously subjected to a surface treatment such as saponification, corona treatment, or plasma treatment. A protective layer may be formed on the film substrate to prevent the film substrate from being corroded by the solvent contained in the low dielectric substrate composition (1). Examples of materials used for the protective layer include polyvinyl alcohol. Furthermore, an anchor coat layer may be formed to enhance adhesion between the protective layer and the substrate. Such an anchor coat layer may be made of either an inorganic or organic material, as long as it enhances adhesion between the protective layer and the substrate. The composition for low dielectric substrates of the present invention is useful for low dielectric substrates, low dielectric sheets, low dielectric coatings, low dielectric adhesives, low dielectric molded products, and the like.

[0135] <Manufacturing method> A method for producing a composition for a low dielectric substrate, and a method for producing a low dielectric constant, high heat resistant substrate and a low dielectric constant, high heat resistant insulating layer from the composition will be specifically described below.

[0136] The composition for low dielectric substrates of the present invention can be used as a liquid resin raw material in a temperature range where it exhibits a liquid crystal phase or an isotropic phase, or it can be dissolved in a solvent and used. To prepare a solution, the polymerizable liquid crystal composition, the necessary solvent, filler, and additives are added, and the mixture is stirred and degassed using a stirrer until the composition is uniform. For example, a planetary mixer is used to stir the mixture at 2000 rpm for 10 minutes, followed by degassing at 2200 rpm for 10 minutes. In addition to planetary mixers, other suitable machines for dispersion include a stirring motor, a mortar and pestle, a three-roll mill, a ball mill, a planetary mill, a bead mill, and a jet mill.

[0137] As the application method, a wet coating method is preferably used in order to uniformly coat the composition for low dielectric substrates. Among wet coating methods, spin coating, which is easy and enables uniform film formation, is preferred when producing small quantities. When productivity is important, gravure coating, die coating, bar coating, reverse coating, roll coating, slit coating, dipping, spray coating, kiss coating, reverse kiss coating, air knife coating, curtain coating, inkjet printing, flexographic printing, screen printing, rod coating, and the like are preferred. The wet coating method can be appropriately selected from these methods depending on the required film thickness, viscosity, curing conditions, and the like.

[0138] When producing sheets, a casting method is used in which the composition for low dielectric substrates is coated onto a release-treated substrate using the method described above and then peeled off.When producing structures, a mold is used and resin molding methods such as press molding, injection molding, and various 3D printer molding methods (ejection lamination methods) can be used.After molding, the mold can be removed and the composition can be fully cured, or it can be fully cured while still in the mold.Furthermore, when producing composite sheets with glass cloth, the raw materials dissolved in a solvent can be impregnated into the glass cloth, the solvent can be dried, and then the composition can be cured by applying pressure and heat. [Example]

[0139] The present invention will be described in more detail by way of examples (including production examples of compounds, compositions, polymers, resins, etc.). The present invention is not limited by these examples.

[0140] [Synthesis Example of Compound (1)] Compound (1) was synthesized according to the procedures shown in Examples such as Synthesis Example 1. Unless otherwise specified, the reaction was carried out under a nitrogen atmosphere. The synthesized compound was identified by methods such as NMR analysis. The device characteristics of Compound (1), compositions, polymers, resins, etc. were measured by the following methods.

[0141] [NMR Analysis] For the measurement, JNM-ECZR manufactured by JEOL was used. 1 For the measurement of 1H-NMR, the sample was dissolved in a deuterated solvent such as CDCl3, and the measurement was carried out at room temperature under the conditions of a frequency of 500 MHz and an integration number of 16 times. Tetramethylsilane was used as an internal standard. 19 For the measurement of 19F-NMR, CFCl3 was used as an internal standard, and the measurement was carried out with an integration number of 32 times. In the description of the nuclear magnetic resonance spectrum, s means singlet, d means doublet, t means triplet, q means quartet, quin means quintet, sex means sextet, m means multiplet, and br means broad.

[0142] [Gas Chromatography Analysis] For the measurement, a GC-2014 type gas chromatograph manufactured by Shimadzu Corporation was used. The column used was a capillary column DB-1 (length 30 m or 15 m, inner diameter 0.25 mm, film thickness 0.25 μm) manufactured by Agilent Technologies Inc. Nitrogen (1 ml / min) was used as the carrier gas. The temperature of the sample vaporization chamber was set to 300 °C, and the temperature of the detector (FID) part was set to 300 °C. The sample was dissolved in an appropriate solvent such as acetone and prepared into a 1 wt% solution, and 1 μl of the obtained solution was injected into the sample vaporization chamber. For the recorder, a GCSolution system manufactured by Shimadzu Corporation or the like was used. <​​​​The measurements were performed using a Shimadzu Prominence (LC-20AD; SPD-20A). The column used was a YMC-Pack ODS-A (length 150 mm, inner diameter 4.6 mm, particle size 5 μm) manufactured by YMC. The eluent was a mixture of acetonitrile and water. Detectors used included a UV detector, RI detector, and CORONA detector. When using a UV detector, the detection wavelength was 254 nm. The sample was dissolved in acetonitrile to prepare a 0.1 wt% solution, and 1 μL of this solution was introduced into the sample chamber. The recorder used was a Shimadzu C-R7Aplus.

[0144] <UV-visible spectroscopy> Measurements were performed using a Shimadzu PharmaSpec UV-1700. The detection wavelength was 190 nm to 700 nm. The sample was dissolved in acetonitrile to prepare a 0.01 mmol / L solution, which was then placed in a quartz cell (light path length 1 cm) for measurement.

[0145] <Measurement sample> When measuring the phase structure and transition temperatures (clearing point, melting point, polymerization initiation temperature, etc.), the compounds themselves were used as samples. (1) Phase structure The sample was placed on a hot plate (Mettler FP-52 hot stage) of a melting point measurement device equipped with a polarizing microscope. The sample was heated at a rate of 3°C / min, and the phase state and its changes were observed under the polarizing microscope to identify the type of phase.

[0146] (2) Transition temperature (℃) Measurements were performed using a high-sensitivity differential scanning calorimeter, X-DSC7000, manufactured by SSI Nanotechnology. The sample was heated and cooled at a rate of 3–5°C / min, and the onset of the endothermic or exothermic peak associated with the phase change of the sample was extrapolated to determine the transition temperature. The melting point and polymerization onset temperature of the compound were also measured using this instrument. The temperature at which a compound transitions from a solid to a liquid crystal phase, such as a smectic or nematic phase, is sometimes abbreviated as the "lower limit temperature of the liquid crystal phase." The temperature at which a compound transitions from a liquid crystal phase to a liquid is sometimes abbreviated as the "clearing point."

[0147] Crystals are represented as C. When the types of crystals can be distinguished, they are represented as C1, C2, etc. Smectic phases are represented as S, and nematic phases as N. When the smectic phases can be distinguished as smectic A, smectic B, smectic C, or smectic F, they are represented as S. A , S B , S C , or S F Liquid (isotropic) is represented as I. The transition temperatures are expressed as, for example, "C 50.0 N 100.0 I." This indicates that the transition temperature from crystal to nematic phase is 50.0°C, and the transition temperature from nematic phase to liquid is 100.0°C.

[0148] [Synthesis Example 1] Compound (S01: Compound (1-1-1a) with R b Both are CH3, n=0, m=0, M and Z 2 Synthesis of compounds where is a single bond TIFF0007739863000030.tif2167 4,4'-Biphenyldiol (S01-a) is commercially available from, for example, Fujifilm Wako Pure Chemical Industries, Ltd.

[0149] TIFF0007739863000031.tif23150 Under a nitrogen atmosphere, a solution of 4,4'-biphenyldiol (S01-a) (10.0 g, 53.70 mmol), N,N'-dicyclohexylcarbodiimide (DCC) (24.4 g, 118.2 mmol), and 4-dimethylaminopyridine (DMAP) (3.94 g, 32.22 mmol) in dichloromethane (100 mL) was cooled to -10 °C and stirred. Methacrylic acid (9.71 g, 112.8 mmol) was added dropwise to the resulting solution, and the temperature was gradually raised to room temperature and stirred for 6 hours. Dichloromethane (100 mL) was added to the reaction solution, which was then filtered and washed three times with water. The organic layer was then concentrated under reduced pressure at 40 °C. The resulting residue was purified by silica gel column chromatography (solvent: toluene / ethyl acetate = 5 / 1 (volume ratio)) and concentrated under reduced pressure at 40°C. The product was then purified by recrystallization filtration (heptane / ethyl acetate = 3 / 3v) and further dried under reduced pressure to obtain compound (S01) (11.8 g, 36.52 mmol). The transition temperature of this compound (S01) was C 150.9 I (°C). The polymerization initiation temperature was 171.9°C.

[0150] In addition, the compound 1 The H-NMR signals were as follows: δ(ppm;CDCl3):7.58-7.56(d,4H), 7.19-7.18(d,4H), 6.37(qd,2H), 6.21(qd,2H), 2.07(dd,6H)

[0151] [Synthesis Example 2] Compound (S02: Compound (1-1-3a) with R b are both CH3, n=0, m=0, M and Z 2 Synthesis of compounds where is a single bond TIFF0007739863000032.tif2166 4,4'-Bicyclohexyldiol (S02-a) is commercially available from, for example, Fujifilm Wako Pure Chemical Industries, Ltd. This raw material was purified using common techniques such as recrystallization and filtration, and the trans isomer was isolated.

[0152] Compound (S02) (3.60 g, 10.76 mmol) was obtained by a method similar to that described in Synthesis Example 1 of Example 1, except that 4,4'-bicyclohexyldiol (S02-a) was used instead of 4,4'-biphenyldiol (S01-a). The transition point of this compound (S01) was C 113.0 I (°C), and the polymerization initiation temperature was 118.8°C.

[0153] In addition, the compound 1 The H-NMR signals were as follows: δ(ppm;CDCl3):6.06(qd,2H), 5.52-5.51(qd,2H), 4.71-4.65(tt,2H), 2.05-2.00( m, 4H), 1.92-1.91(dd,6H), 1.80-1.77(m,4H), 1.38-1.36(m,4H), 1.15-1.08(m,6H)

[0154] [Synthesis Example 3] Compound (S03: Compound (1-1-1a) with R b Both are CH3, n=0, m=6, M is oxygen, Z 2 Synthesis of compounds where is a single bond TIFF0007739863000034.tif21112 4,4'-Biphenyldiol (S03-a) is commercially available from, for example, Fujifilm Wako Pure Chemical Industries, Ltd. TIFF0007739863000035.tif46165

[0155] (1st stage) Under a nitrogen atmosphere, a solution of 4,4'-biphenyldiol (S01-a) (10.0 g, 53.70 mmol), sodium hydroxide (4.51 g, 112.8 mmol), and 6-bromo-1-hexanol (20.4 g, 112.8 mmol) in N,N-dimethylformamide (100 mL) was heated and stirred at 60°C for 6 hours. The reaction solution was filtered, and the crystals were washed three times with ethanol and then dried under reduced pressure to obtain compound (S03-b) (14.0 g, 36.22 mmol).

[0156] (Second stage) Compound (S03) (2.90 g, 5.55 mmol) was obtained in the same manner as in Synthesis Example 1 of Example 1, except that compound (S03-b) obtained in the previous step and 4,4'-bicyclohexyldiol (S02-a) were used instead of 4,4'-biphenyldiol (S01-a). The transition temperature of this compound (S03) was C 61.9 I (°C). The polymerization initiation temperature was 163.3°C.

[0157] In addition, the compound 1 The H-NMR signals were as follows: δ(ppm;CDCl3):7.45-7.43(d,4H), 6.94-6.91(d,4H), 6.09(qd,2H), 5.54-5.53(qd,2H), 4.17-4.14 (t,4H), 3.99-3.97(t,4H), 1.93(dd,6H), 1.84-1.78(tt,4H), 1.74-1.68(tt,4H), 1.55-1.42(m,8H)

[0158] [Synthesis Example 4] Compound (S04): Compound (1-1-3a), R b are both CH3, n=0, m=6, M is a single bond, Z 2 Synthesis of compounds where is a single bond TIFF0007739863000036.tif211024,4'-Bicyclohexanone (S04-a) is commercially available from, for example, Tokyo Chemical Industry Co., Ltd.

[0159] TIFF0007739863000037.tif91159

[0160] (1st stage) 1-Bromo-7-methoxyheptane can be easily prepared using standard organic synthesis methods. Under a nitrogen atmosphere, 1-bromo-7-methoxyheptane is added to a mixture of magnesium and THF to prepare the Grignard reagent. A THF solution of 4,4'-bicyclohexanone (S04-a) is added to the prepared Grignard reagent at 30°C and stirred for 1 hour. The reaction mixture is slowly added to a 1N HCl solution and extracted with toluene. The organic layer is washed three times with water. The resulting organic layer is concentrated under reduced pressure to obtain compound (S04-b).

[0161] (Second stage) Under a nitrogen atmosphere, a toluene solution of compound (S04-b) obtained in the previous step and p-toluenesulfonic acid monohydrate is heated and stirred at 110°C for 1 hour while removing the generated water using a Dehnstack trap. Toluene is added to the reaction solution, washed three times with water, and the organic layer is concentrated under reduced pressure at 40°C. The resulting residue is purified by silica gel column chromatography (solvent: toluene) and recrystallization filtration (heptane / ethanol) to obtain compound (S04-c).

[0162] (3rd stage) Compound (S04-c) obtained in the previous step and palladium / carbon are added to a toluene / isopropyl alcohol (IPA) mixed solution at room temperature, and H2 is added and stirred under a H2 atmosphere for 6 hours. The reaction solution is filtered and concentrated under reduced pressure at 40°C, and the resulting residue is purified by silica gel column chromatography (solvent: toluene) and recrystallization filtration (solvent: heptane / ethanol) to obtain compound (S04-d).

[0163] (4th stage) To the acetone solution of compound (S04-d) obtained in the previous step, add 3N-HCl aqueous solution at room temperature and stir for 2 hours. The reaction solution is extracted with toluene, washed three times with water, and then concentrated under reduced pressure at 40°C. The resulting residue is washed with ethanol and dried under reduced pressure to obtain compound (S04-e).

[0164] (5th paragraph) Compound (S04) is obtained by the same method as described in Synthesis Example 1 of Example 1, except that compound (S04-e) is used instead of 4,4'-biphenyldiol (S01-a).

[0165] [Synthesis example of polymer obtained by polymerizing compound (1)] Polymers obtained by polymerizing compound (1) were synthesized according to the procedures shown in Synthesis Examples 5 to 10. Unless otherwise specified, the reactions were carried out under a nitrogen atmosphere. The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polymers were measured by the following methods.

[0166] <Gel permeation chromatography (GPC) analysis> The weight-average molecular weight (Mw) and number-average molecular weight (Mn) were determined by gel permeation chromatography (GPC). The measurement device used was a Nexera GPC System (Shimadzu Corporation). GPC columns included PLgel 5 μm MIXED-D (Agilent), GPC KF-804 (Showa Denko K.K.), GPC KF-805 (Showa Denko K.K.), and TSKgel α-3000 (Tosoh Corporation). Tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, or dimethyl sulfoxide (containing lithium bromide as an additive) was used as the carrier, and polystyrene or pullulan was used as the molecular weight standard. The polydispersity (Mw / Mn) of the polymer was calculated from the Mw and Mn measurements.

[0167] [Synthesis Example 5] Synthesis of polymer (S02-1) Compound (S02) (3.00 g, 100 parts by weight) and toluene (70 g) were added to a 300 mL three-neck round-bottom flask and stirred at 60 °C for 30 minutes. Next, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (0.60 g, 20 parts by weight) was added to the flask and stirred at 60 °C for 2 hours. After cooling the reaction mixture to room temperature, the organic solvent was removed by concentration under reduced pressure to obtain a crude polymer (S02-1c) (3.38 g). The crude polymer was diluted with toluene (20 mL) and added to heptane (350 mL). The resulting precipitate was filtered and purified by drying under reduced pressure to obtain 0.34 g of polymer (S02-1) as a white powder. GPC analysis of the polymer showed that the crude polymer (S02-1c) had an Mn of 283, an Mw of 2,816, and an Mw / Mn of 9.94, while the purified polymer (S02-1) had an Mn of 1,147, an Mw of 5,075, and an Mw / Mn of 4.43.

[0168] [Synthesis Example 6] Synthesis of polymer (S02-2) Compound (S02) (3.00 g, 100 parts by weight) and toluene (70 g) were added to a 300 mL three-neck round-bottom flask and stirred at 60 °C for 30 minutes. Next, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (0.45 g, 15 parts by weight) was added to the flask and stirred at 60 °C for 2 hours. After cooling the reaction mixture to room temperature, the organic solvent was removed by vacuum concentration to obtain a crude polymer (S02-2c) (3.31 g). The crude polymer was diluted with toluene (20 mL) and added to heptane (350 mL). The resulting precipitate was filtered and purified by drying under reduced pressure to obtain 0.32 g of polymer (S02-2) as a white powder. GPC analysis of the polymer showed that the crude polymer (S02-2c) had an Mn of 271, an Mw of 5,307, and an Mw / Mn of 19.94, while the purified polymer (S02-2) had an Mn of 1,183, an Mw of 12,506, and an Mw / Mn of 10.57.

[0169] [Synthesis Example 7] Synthesis of polymer (S02-3) Compound (S02) (3.00 g, 100 parts by weight) and toluene (70 g) were added to a 300 mL three-neck round-bottom flask equipped with a reflux condenser and stirred at 100 °C for 30 minutes. Next, 2,2'-azobis(2,4-dimethylvaleronitrile) (0.90 g, 30 parts by weight) was added to the flask and stirred at 100 °C for 2 hours. After cooling the reaction mixture to room temperature, the organic solvent was removed by concentration under reduced pressure to obtain a crude polymer (S02-3c) (3.22 g). The crude polymer was diluted with toluene (20 mL) and added to heptane (350 mL). The resulting precipitate was filtered and purified by drying under reduced pressure to obtain 1.62 g of polymer (S02-3) as a white powder. GPC analysis of the polymer showed that the crude polymer (S02-3c) had an Mn of 447, an Mw of 22,467, and an Mw / Mn of 50.24, while the purified polymer (S02-3) had an Mn of 4,317, an Mw of 27,784, and an Mw / Mn of 6.49.

[0170] [Synthesis Example 8] Synthesis of polymer (S02-4) Compound (S02) (3.00 g, 100 parts by weight) and toluene (70 g) were added to a 300 mL three-neck round-bottom flask equipped with a reflux condenser and stirred at 100 °C for 30 minutes. Next, 2,2'-azobis(2,4-dimethylvaleronitrile) (0.30 g, 10 parts by weight) was added to the flask and stirred at 100 °C for 2 hours. After cooling the reaction mixture to room temperature, the organic solvent was removed by concentration under reduced pressure to obtain a crude polymer (S02-4c) (3.01 g). The crude polymer was diluted with toluene (20 mL) and added to heptane (350 mL). The resulting precipitate was filtered and purified by drying under reduced pressure to obtain 1.64 g of polymer (S02-4) as a white powder. GPC analysis of the polymer showed that the crude polymer (S02-4c) had an Mn of 477, an Mw of 18,729, and an Mw / Mn of 39.27, while the purified polymer (S02-4) had an Mn of 3,050, an Mw of 21,245, and an Mw / Mn of 3.73.

[0171] [Synthesis Example 9] Synthesis of polymer (S02-5) Compound (S02) (3.00 g, 100 parts by weight), toluene (15 g), and thioglycolic acid (3.00 g, 100 parts by weight) were added to a 100 mL three-neck round-bottom flask and stirred at 80°C for 30 minutes. Next, 2,2'-azobisisobutyronitrile (0.165 g, 5.5 parts by weight) was added to the flask and stirred at 80°C for 2 hours. The reaction mixture was cooled to room temperature and diluted with ethyl acetate. The organic layer was washed with pure water, dried over magnesium sulfate, and the organic solvent was removed by vacuum concentration to obtain polymer (S02-5) (2.96 g). GPC analysis of polymer (S02-5) revealed that Mn was 1,168, Mw was 3,415, and Mw / Mn was 2.92.

[0172] [Examples 1 to 5: Evaluation of physical properties of polymers obtained by polymerizing compound (1)] The physical properties of the polymers (S02-1), (S02-2c), (S02-2), (S02-3c), and (S02-4) were evaluated by the following procedures.

[0173] <Test for leaching from glass cloth> 0.2 g of the synthesized polymer was dissolved by gradually adding 1-methyl-2-pyrrolidone (Fujifilm Wako Pure Chemical Industries, Ltd., 97%) (NMP), and this solution was impregnated into a 3 cm square piece of glass cloth (Nitto Boseki Co., Ltd., NE Glass 2116). This sample was dried on a hot plate set to 120°C. After measuring the weight after drying, it was placed on a hot plate heated to 160°C and heat-treated for 1 hour. The amount of exudation was calculated as follows: weight after heat treatment - weight before heat treatment. A resin with a lower amount of exudation is considered to be superior as a substrate resin.

[0174] <Creating a sample for measuring the relative permittivity> The polymer solution prepared in the same manner as in the exudation test was applied to a polyimide film (Kapton 200H, manufactured by Panac Corporation) to a thickness of approximately 60 μm, and a two-layer sample was similarly obtained. From the film-formed sample, a 50 mm × 50 mm sample for evaluating the relative dielectric constant was cut out and evaluated.

[0175] <Method for evaluating relative permittivity> Samples cut into 50mm squares were measured using an AET Corporation cavity resonator (TE mode 10 GHz, 28 GHz) connected to a vector network analyzer (Anritsu MS46522B-043) to measure the resonant frequency shift and attenuation, and the dielectric constant was calculated using the company's software. Since the measurements were for a two-layer structure consisting of a polyimide film and a cured film, the values ​​measured for the polyimide film alone were used to calculate the dielectric constant of the cured film alone using the company's calculation sheet. To minimize the influence of moisture content in the strips when comparing data, the strips were shaped the day before the measurements. The evaluation of the dielectric constant began after the samples had been left to stand for at least 60 minutes in a laboratory at 20°C and 48% humidity.

[0176] [Comparative Example 1] Using compound S02 (the compound used as the raw material for the polymer), evaluation samples were prepared in the same manner as in Examples 1 to 5, and the weight change before and after heat treatment was determined. Samples for measuring the relative dielectric constant were also prepared, but the film was brittle and warped during curing, making it impossible to obtain a 5 cm square sample that was crack-free and could be placed in the measuring machine.

[0177] Comparative Example 2 6.92 g of bisphenol F type epoxy (807, manufactured by Mitsubishi Chemical Corporation), 4,4'-methylenedianiline (98% manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 2.0 g of NMP were mixed to form a transparent liquid, and then a comparative sample was prepared in the same manner as in Examples 1 to 5, and the weight change was evaluated in the same manner as in Examples 1 to 5. The dielectric constant was also measured by preparing a cured film on a polyimide film.

[0178] Table 1 shows the weight changes and relative dielectric constants before and after the heat treatment obtained in Examples 1 to 5 and Comparative Examples 1 and 2.

[0179] TIFF0007739863000038.tif67144

[0180] Table 1 shows that when the polymer of the present invention is used as a prepolymer, there is less exudation from the glass cloth than when the compound used as the raw material for the polymer is used, and therefore substrate moldability is improved. Furthermore, since the polymer of the present invention has a lower relative dielectric constant than general-purpose epoxy resins, it is also found to be suitable as a raw material for low-dielectric substrates for high-frequency equipment such as high-speed communication equipment and high-speed data servers.

Claims

1. A polymer obtained by polymerizing a liquid crystal compound having a polymerizable group at its terminal, which is represented by at least one compound selected from the group consisting of formula (1-1-3a): In formula (1-1-3a), R ｂ is hydrogen or methyl, Z ２ is a single bond m is an integer from 0 to 6, M is a single bond or oxygen; In the formula, R ｂ When there are a plurality of , m, or M, they may be the same or different.

2. 10. The polymer of claim 1 which is the product of polymerization in the presence of a mercaptan chain transfer agent.

3. The polymer according to claim 2, which is a product of polymerization in the presence of a mercaptan chain transfer agent having a carboxyl group in the molecule.

4. The polymer according to any one of claims 1 to 3, which has a weight average molecular weight of 300,000 or less.

5. The polymer according to any one of claims 1 to 3, which has a weight average molecular weight of 50,000 or less.

6. A composition for low dielectric substrates, comprising the polymer according to any one of claims 1 to 5.

7. The composition for a low dielectric substrate according to claim 6 , further comprising a non-polymerizable liquid crystal compound.

8. The composition for a low dielectric substrate according to claim 6 or 7, further comprising an inorganic filler.

9. 9. The composition for low dielectric substrates according to claim 8, wherein the inorganic filler is at least one selected from the group consisting of spherical silica, pulverized silica, hollow silica, fumed silica, aluminum nitride, boron nitride, magnesium oxide, aluminum oxide, zinc oxide, titanium oxide, aluminum oxide, magnesium hydroxide, and aluminum hydroxide.

10. A cured product obtained by curing the composition for low dielectric substrates according to any one of claims 6 to 9.

11. The cured product according to claim 10, which has a relative dielectric constant at 10 GHz of less than 3.

0.

12. 12. The cured product according to claim 10, having a thermal conductivity of 1 W / m·K or more.

13. An insulating film using the cured product according to claim 11 or 12.

14. A film using the cured product according to claim 11 or 12.

15. A sheet using the cured product according to claim 11 or 12.

16. An electronic device using the cured product according to claim 11 or 12, the insulating film according to claim 13, the film according to claim 14, or the sheet according to claim 15.

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