(METH)acrylic acid ester and (METH)acrylic polymer

Abstract

The present disclosure pertains to a (meth)acrylic acid ester represented by formula (M1).

Description

(Meth)acrylic acid esters and (meth)acrylic polymers

[0001] This disclosure relates to (meth)acrylic acid esters, (meth)acrylic polymers, molding materials, 3D printing materials, inkjet ink materials, curable compositions, molded articles, and electronic components.

[0002] Cured products obtained using (meth)acrylic acid esters and (meth)acrylic polymers exhibit excellent processability, transparency, impact resistance, and durability, and are used in a variety of applications such as paints, adhesives, and sealants (for example, Patent Document 1).

[0003] International Publication No. 2018 / 066594

[0004] When cured (meth)acrylic acid esters and (meth)acrylic polymers are used in electronic components, further improvements in heat resistance are desired in line with the miniaturization and increased functionality of electronic components in recent years.

[0005] Therefore, this disclosure provides (meth)acrylic acid esters, (meth)acrylic polymers, molding materials, 3D printing materials, inkjet ink materials, and curable compositions that can obtain molded articles having excellent heat resistance. Furthermore, this disclosure provides molded articles and electronic components having excellent heat resistance.

[0006] The present invention includes, but is not limited to, the following embodiments. One embodiment relates to a (meth)acrylic acid ester represented by the following formula (M1). (In the formula, A each independently represents a (meth)acryloyloxy group, B each independently represents an alkyl group having 1 to 3 carbon atoms, X and Y each independently represent a single bond or a double bond, m, n, s and t each independently represent a number of 0 or more, m and n satisfy 1 ≤ m + n, and s and t satisfy 1 < s + t.) Another embodiment relates to a (meth)acrylic polymer comprising a structural unit represented by the following formula (P1). (In the formula, C independently represents a group represented by the following formula (P1-1), B independently represents an alkyl group having 1 to 3 carbon atoms, X and Y independently represent a single bond or a double bond, m, n, s and t independently represent a number of 0 or more, m and n satisfy 1 ≤ m + n, and s and t satisfy 1 < s + t.) (In the formula, R represents a hydrogen atom or a methyl group, the dashed line represents a bonding site with a carbon atom in formula (P1), and the asterisk (*) represents a bonding site with another structural unit.) Another embodiment relates to a molding material, a 3D printing material, and an inkjet ink material, which contains at least one selected from the group consisting of the (meth)acrylic acid ester and the (meth)acrylic polymer. Another embodiment relates to a curable composition, which contains at least one selected from the group consisting of the (meth)acrylic acid ester, the (meth)acrylic polymer, the molding material, the 3D printing material, and the inkjet ink material, and a polymerization initiator. Another embodiment relates to a molded article obtained using at least one selected from the group consisting of the (meth)acrylic acid ester, the (meth)acrylic polymer, the molding material, the 3D printing material, the inkjet ink material, and the curable composition. Another embodiment relates to an electronic component obtained using at least one selected from the group consisting of the (meth)acrylic acid ester, the (meth)acrylic polymer, the molding material, the 3D printing material, the inkjet ink material, and the curable composition, or including the molded body.

[0007] This disclosure provides (meth)acrylic acid esters, (meth)acrylic polymers, molding materials, 3D printing materials, inkjet ink materials, and curable compositions that can obtain molded articles with excellent heat resistance. Furthermore, this disclosure provides molded articles and electronic components with excellent heat resistance.

[0008] Embodiments of the present invention will now be described. The present invention is not limited to the following embodiments. The following embodiments can be implemented individually or in combination. Combinations of multiple embodiments are also included in the present invention. In this disclosure, numerical ranges indicated using "~" mean a range that includes the numbers listed before and after "~" as the minimum and maximum values, respectively. In numerical ranges described stepwise in this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. The upper or lower limits of numerical ranges described in this disclosure may be replaced with values ​​shown in the examples. A numerical value may be selected from the upper and lower limits described stepwise in this disclosure to form a stepwise numerical range. The upper and lower limits described in this disclosure may be replaced with values ​​shown in the examples. In this disclosure, each component may contain multiple types of the corresponding substance. If multiple types of the corresponding substance exist in the composition, the content or amount of each component means the total content or amount of the multiple types of substances present in the composition, unless otherwise specified. In this disclosure, each structure in the polymer may contain multiple types of the corresponding structure. If multiple types of structures corresponding to each structure exist in a polymer, the content or amount of each structure refers to the total content or amount of such multiple types of structures present in the polymer, unless otherwise specified. In this disclosure, “layer” includes continuous layers and discontinuous layers. The thickness of a “layer” may be uniform or non-uniform. The outer edge in the planar direction and the outer edge in the thickness direction of a “layer” may be clear or unclear, respectively. The same applies to “film.”

[0009] <(meth)acrylic acid esters> In some embodiments, (meth)acrylic acid esters are represented by the following formula (M1). (Meth)acrylic acid esters are used, for example, as materials for obtaining (meth)acrylic polymers, materials for obtaining molded articles such as films, etc. In this disclosure, the term "(meth)acrylic" is used as a term that encompasses "acrylic" and "methacrylic". In this disclosure, (meth)acrylic acid esters represented by formula (M1) may be referred to as "(meth)acrylic acid ester (M1)". The same applies to (meth)acrylic acid esters, structural units, etc., represented by other formulas.

[0010] In the formula, A independently represents a (meth)acryloyloxy group, B independently represents an alkyl group having 1 to 3 carbon atoms, and X and Y independently represent a single bond or a double bond. m, n, s, and t independently represent a number greater than or equal to 0, m and n satisfy 1 ≤ m + n, and s and t satisfy 1 < s + t.

[0011] (Meth)acrylic acid ester (M1) may be a single compound or a mixture containing multiple compounds. If it is a mixture containing multiple compounds, m, n, s, and t are the average values ​​of the multiple compounds.

[0012] X and Y are each independently single or double bonds. For example, (meth)acrylic acid ester (M1) in which X and Y are single bonds is tetrahydrodicyclopentadiene (tricyclo[5.2.1.0 ２，６ It has a decane skeleton. For example, (meth)acrylic acid ester (M1) in which X is a single bond and Y is a double bond is dihydrodicyclopentadiene (tricyclo[5.2.1.0 ２，６It has a deca-3-ene skeleton. When a (meth)acrylic acid ester (M1) in which X is a single bond and Y is a double bond is used, a cross-linked structure can be introduced into the (meth)acrylic polymer or molded product as needed. Also, since it is easy to introduce functional groups into the (meth)acrylic acid ester (M1) when X is a single bond and Y is a double bond, the (meth)acrylic acid ester (M1) is easy to use as a raw material when synthesizing other monomers. The structures of tetrahydrodicyclopentadiene and dihydrodicyclopentadiene are shown below.

[0013] Tetrahydrodicyclopentadiene (X and Y are single bonds).

[0014] Dihydrodicyclopentadiene (where X is a single bond and Y is a double bond).

[0015] (Meth)acrylic acid ester (M1) has a ring structure substituted with an alkyl group. By using (meth)acrylic acid ester (M1) having a ring structure substituted with an alkyl group, a (meth)acrylic polymer with a high glass transition temperature can be obtained, improving the heat resistance of the molded article. It is thought that the glass transition temperature of the polymer is high because the movement of the structure derived from (meth)acrylic acid ester (M1) is suppressed due to steric hindrance by the alkyl group. Furthermore, by using (meth)acrylic acid ester (M1) having a ring structure substituted with an alkyl group, the dielectric constant and dielectric loss tangent of the polymer and molded article tend to be lower. It is thought that the dielectric constant decreases because the polarization with respect to volume decreases due to the volume increase due to the alkyl group, and the mobility of the polymer molecular chains is restricted, weakening the response to the electric field. In addition, it is thought that the dielectric constant decreases because the steric hindrance caused by the volume increase due to the alkyl group in (meth)acrylic acid ester (M1) suppresses the rotational motion of the polymer molecular chains, thereby reducing the mobility of the dipole and lowering the dielectric loss tangent. Polymers and molded articles with excellent heat resistance, low dielectric constant, and low dielectric loss tangent can be preferably used as protective layers, adhesive layers, and the like for electronic components. Note that the discussions and speculations described in this disclosure are not intended to limit the present invention.

[0016] A is a group that bonds to any carbon atom at positions 1 to 10 of the ring structure shown in the following formula (M1-1). For example, (A) ｍ (A) may be a group bonded to any carbon atom at positions 1 and 7-10. ｎ m and n are numbers satisfying 1 ≤ m + n. m and n are numbers satisfying 1.0 ≤ m + n ≤ 2.0, preferably 1.0 ≤ m + n ≤ 1.5, and more preferably 1.0 ≤ m + n ≤ 1.2.

[0017]

[0018] When A is a group bonded to either the 8th or 9th carbon atom, the movement of the molecular chains of the polymer and the structure derived from the (meth)acrylic acid ester (M1) are suppressed, which tends to result in a higher glass transition temperature and a lower dielectric loss tangent. (Meth)acrylic acid esters in which A is bonded to either the 8th or 9th carbon atom are also easily synthesized.

[0019] When A is an acryloyloxy group, curability by irradiation with active energy rays tends to be better. When A is a methacryloyloxy group, a high glass transition temperature is obtained, and heat resistance tends to be improved. When a (meth)acrylic acid ester has multiple A groups, some or all of the A groups may be the same as each other, or some or all of the A groups may be different from each other. Using a (meth)acrylic acid ester having only one A group tends to prevent the molded article from becoming brittle and the viscosity of the (meth)acrylic polymer from becoming high.

[0020] B is a group that bonds to any of the carbon atoms at positions 1 to 10 in the above formula (M1-1). For example, (B) ｓ (B) may be a group bonded to any carbon atom at positions 1 and 7-10. ｔ is a group bonded to any carbon atom between positions 2 and 6. s and t are numbers satisfying 1 < s + t. s and t are numbers satisfying 1.0 < s + t ≤ 2.0, preferably 1.5 ≤ m + n ≤ 2.0, and more preferably 1.7 ≤ m + n ≤ 2.0.

[0021] When B is a group bonded to either the 8th or 9th carbon atom, the movement of the molecular chains of the polymer and the structure derived from the (meth)acrylic acid ester (M1) are suppressed, which tends to result in a higher glass transition temperature and a lower dielectric loss tangent. (Meth)acrylic acid esters having B bonded to either the 8th or 9th carbon atom and B bonded to either the 3rd or 4th carbon atom are easy to synthesize.

[0022] B may be a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. From the viewpoint of obtaining a high glass transition temperature, B is preferably a methyl group, an ethyl group, or an isopropyl group, and more preferably a methyl group or an isopropyl group. In some embodiments, it is thought that the bulkier B is, the more the rotational motion of the molecular chain can be suppressed, and thus the higher the glass transition temperature of the polymer tends to be. In some embodiments, it is thought that the shorter the chain length of B, the lower the mobility, and thus the higher the glass transition temperature of the polymer tends to be. From the viewpoint of ease of manufacture and raw material cost, B is preferably a methyl group or an ethyl group, and more preferably a methyl group. When a (meth)acrylic acid ester has multiple B groups, some or all of the multiple B groups may be the same as each other, or some or all of the multiple B groups may be different from each other.

[0023] In some embodiments, the (meth)acrylic acid ester (M1) includes the (meth)acrylic acid ester represented by the following formula (M0). The content of the (meth)acrylic acid ester (M0) may be, for example, 50 to 100 mol%, 70 to 100 mol%, or 80 to 100 mol%, based on the (meth)acrylic acid ester (M1).

[0024] In the formula, A represents a (meth)acryloyloxy group, B independently represents an alkyl group having 1 to 3 carbon atoms, and X and Y independently represent a single bond or a double bond.

[0025] A may be a group that bonds to any carbon atom between positions 1 and 10, preferably to carbon atoms between positions 1 and 7 to 9, and more preferably to carbon atom 8 or 9. B may each be a group that independently bonds to any carbon atom between positions 1 and 10, preferably to carbon atoms between positions 8 or 9 and carbon atoms between positions 3 or 4.

[0026] In a preferred embodiment, the (meth)acrylic acid ester (M1) includes a (meth)acrylic acid ester represented by the following formula (M2). In the (meth)acrylic acid ester (M2), for example, the bonding position of the (meth)acryloyloxy group may be the carbon atom at the 8th position.

[0027] In the formula, R represents a hydrogen atom or a methyl group.

[0028] In a preferred embodiment, the (meth)acrylic acid ester (M1) includes a (meth)acrylic acid ester represented by the following formula (M3). In the (meth)acrylic acid ester (M3), for example, the bonding position of the (meth)acryloyloxy group may be the carbon atom at the 8th position.

[0029] In the formula, R represents a hydrogen atom or a methyl group.

[0030] The production method of the (meth)acrylic acid ester (M1) is not particularly limited. For example, it can be produced by a method using dimethyldicyclopentadiene (DMDCPD) as a raw material. Below, an example of a method for synthesizing the (meth)acrylic acid ester (M2) and the (meth)acrylic acid ester (M3) using 3,9-dimethyltricyclo[5.2.1.0 ２，６ dec-3,8-diene as dimethyldicyclopentadiene (DMDCPD) is shown.

[0031]

[0032] In the synthesis method of the (meth)acrylic acid ester (M2), first, water is added to DMDCPD to obtain DMDCPD-OH. Next, DMDCPD-OH is hydrogenated to obtain hydrogenated DMDCPD-OH. Then, the (meth)acrylic acid ester (M2) is obtained by an ester exchange reaction between hydrogenated DMDCPD-OH and the (meth)acrylic acid ester.

[0033] In the synthesis method of the (meth)acrylic acid ester (M3), first, water is added to DMDCPD to obtain DMDCPD-OH. Next, the (meth)acrylic acid ester (M3) is obtained by an ester exchange reaction between DMDCPD-OH and the (meth)acrylic acid ester.

[0034] An acid catalyst, such as an aqueous sulfuric acid solution, is used for the addition of water to DMDCPD. The amount of sulfuric acid used is, for example, 5 to 30 mol% based on DMDCPD. The reaction temperature may be 50 to 110°C, and the reaction time may be 1 to 25 hours.

[0035] The hydrogenation reaction of DMDCPD-OH can be carried out under a hydrogen atmosphere at a pressure of 0.01 to 15.0 MPa and a temperature of 30 to 150°C. As a catalyst, for example, a catalyst in which metals such as platinum, palladium, nickel, ruthenium, and cobalt are supported on a support can be used. Examples of supports include carbon, silica, and alumina. The amount of catalyst used may be 0.01 to 20% by mass relative to the mass of DMDCPD-OH.

[0036] For the transesterification reaction, alkyl esters of (meth)acrylate, such as methyl (meth)acrylate and ethyl (meth)acrylate, can be used as the (meth)acrylate ester. The catalyst may be an alkali metal catalyst, an organotitanium catalyst, a zirconium catalyst, etc., and it is preferable to use an organotitanium catalyst. Examples include titanium(IV) tetraethoxide, titanium(IV) tetrapropoxide, and titanium(IV) tetraisopropoxide. In the transesterification reaction, it is preferable to use an excess amount of alkyl (meth)acrylate relative to DMDCPD-OH or hydrogenated DMDCPD-OH in terms of shortening the reaction time and improving the reaction conversion rate. The amount of alkyl (meth)acrylate used may be 2 to 30 moles of alkyl (meth)acrylate per mole of DMDCPD-OH or hydrogenated DMDCPD-OH. Polymerization inhibitors such as methoxyphenol and hydroquinone may be used in the reaction. The reaction can be carried out at atmospheric pressure or reduced pressure at 60 to 130°C.

[0037] An example of the synthesis method of (meth)acrylic acid ester (M2) is given below. The synthesis method is not limited to the following. ((1) Synthesis of DMDCPD-OH) A reaction kettle equipped with a stirrer, a thermometer, and a cooler is placed under a nitrogen atmosphere, and 1,000 g (6.24 mol) of dimethyldicyclopentadiene (DMDCPD) and 627.7 g of 20% by mass sulfuric acid aqueous solution (H ２ SO ４ 1.28 mol) are charged and reacted at 50 to 150 °C for about 1 to 25 h. After cooling, the organic layer and the aqueous layer are separated. Then, the organic layer is washed multiple times with a basic aqueous solution. Operations such as concentration and distillation are carried out to obtain the target product, DMDCPD-OH.

[0038] ((2) Synthesis of hydrogenated DMDCPD-OH by hydrogenation reaction) 315 g (1.77 mol) of DMDCPD-OH synthesized in (1) and 0.221 g (Pd 0.0417 mol) of Pd / C catalyst (Pd 5% by mass) are charged into a stainless steel high-pressure reaction kettle equipped with a stirrer and a thermocouple. The Pd / C catalyst (Pd 5% by mass) is used with a target of 100 ppm to 2,000 ppm of the raw material weight. While stirring, the inside of the reaction kettle is replaced with a hydrogen atmosphere, pressurized, and the temperature of the reaction kettle is raised to 50 to 100 °C. After the reaction is completed, stirring is stopped and cooled. The mixture after the reaction is suction filtered to remove the catalyst and obtain the target product, hydrogenated DMDCPD-OH.

[0039] ((3) Synthesis of acrylic acid ester by transesterification reaction) 100 g (0.550 mol) of hydrogenated DMDCPD-OH synthesized in (2), 555 g (5.55 mol) of ethyl acrylate, and 0.032 g (0.258 mmol) of 4-methoxyphenol are charged into a reaction vessel equipped with a stirrer, a thermometer, an air introduction tube, and a rectification column, and heated to reflux while blowing dry air. 1.60 g (5.63 mmol) of titanium(IV) tetraisopropoxide (TPT) is charged, and the pressure inside the system is adjusted so that the temperature of the liquid in the flask becomes 60 to 130 °C. At the end of the reaction, the reaction solution is cooled, the pressure inside the reaction vessel is returned to normal pressure, and a deactivation operation of the organometallic catalyst is performed. Then, a liquid separation operation is performed, the organic layer is concentrated, and filtration is performed to obtain the target product, acrylic acid ester.

[0040] By using (meth)acrylic acid ester (M1), a (meth)acrylic polymer with a high glass transition temperature can be obtained, and the heat resistance of the molded article can be improved. In some embodiments, (meth)acrylic acid ester (M1) may satisfy the following properties: The glass transition temperature (Tg) of the polymer obtained by polymerizing (meth)acrylic acid ester (M1) is 180°C or higher.

[0041] The polymer used to measure the glass transition temperature here is a polymer obtained by polymerizing a monomer containing 100 mol% of (meth)acrylic acid ester (M1) as a raw material monomer. A polymerization initiator may be used for polymerization. For example, azobisisobutyronitrile (AIBN) can be used as a polymerization initiator. Using a (meth)acrylic acid ester (M1) with a glass transition temperature of 180°C or higher makes it easier to obtain a molded article with better heat resistance. The glass transition temperature is preferably 190°C or higher.

[0042] Generally, the glass transition temperature of (meth)acrylic polymers tends to increase as the number-average molecular weight and weight-average molecular weight increase. Furthermore, the molecular weight dependence of the glass transition temperature tends to decrease as the number-average molecular weight and weight-average molecular weight increase. The number-average molecular weight of the polymer used to measure the glass transition temperature may be, for example, 30,000 to 35,000, and the weight-average molecular weight may be, for example, 75,000 to 80,000. However, the glass transition temperature, number-average molecular weight, and weight-average molecular weight of (meth)acrylic polymers synthesized using (meth)acrylic acid ester (M1) and actually used as materials for molded articles are not limited to these numerical ranges and may be appropriately adjusted according to the application, such as molded articles or electronic components.

[0043] In this disclosure, the glass transition temperature (Tg) of the (meth)acrylic polymer can be determined from the obtained DSC curve by performing differential scanning calorimetry using a differential scanning calorimeter (DSC). The glass transition temperature (Tg) of the (meth)acrylic polymer may be the midpoint glass transition temperature (Tmg) (the temperature at the point where a line equidistant in the vertical direction from the extended line of each baseline intersects with the curve of the stepwise transition portion of the glass transition). For example, Shimadzu Corporation's "DSC-60APlus" can be used as the measuring device. Sample preparation and measurement are carried out according to the following method. (Sample conditioning) Fill an aluminum container with 5 to 10 mg of (meth)acrylic polymer and set it in the measuring device. An empty container or a container filled with alumina is used as a reference. Heat the container to 200 to 230°C at 10°C / min under a nitrogen atmosphere, hold for 10 minutes, and then cool to 30°C. (Measurement) After holding the device at 30°C until it stabilizes, the temperature is heated to 200-230°C at a heating rate of 10°C / min, and the measurement is performed.

[0044] By using (meth)acrylic acid ester (M1), (meth)acrylic polymers and molded articles with low relative permittivity and dielectric loss tangent can be obtained. In some embodiments, (meth)acrylic acid ester (M1) may satisfy the following properties. The relative permittivity, dielectric loss tangent, or both of the following are within the ranges of the film obtained using (meth)acrylic acid ester (M1). The relative permittivity (Dk) at a frequency of 10 GHz and 25°C is 2.0 or higher. The relative permittivity (Dk) is preferably 2.3 or higher, 2.5 or higher, or 2.7 or higher. The dielectric loss tangent (Df) at a frequency of 10 GHz and 25°C is 0.020 or lower. The dielectric loss tangent (Df) is preferably 0.015 or lower, 0.010 or lower, or 0.005 or lower.

[0045] The polymer used to measure the relative permittivity and dielectric loss tangent here is a polymer obtained by polymerizing a monomer containing 100 mol% (meth)acrylic acid ester (M1) as a raw material monomer using a polymerization initiator. By using (meth)acrylic acid ester (M1) whose relative permittivity and dielectric loss tangent are within the above range, the relative permittivity and dielectric loss tangent of the (meth)acrylic polymer and molded article can be reduced. However, the relative permittivity and dielectric loss tangent of (meth)acrylic polymers and molded articles (e.g., films) obtained using (meth)acrylic acid ester (M1) and actually used are not limited to these numerical ranges and can be adjusted as appropriate depending on the application.

[0046] The preparation of samples for measuring relative permittivity and dielectric loss tangent, and the measurement of relative permittivity and dielectric loss tangent, shall be carried out according to the following method. (Sample preparation) Add 3% by mass of a photoinitiator, based on the mass of the (meth)acrylic acid ester, to (meth)acrylic acid ester and stir to obtain a mixture. Coat the mixture onto a separator film and adjust the film thickness to approximately 200 to 500 μm. UV lamp (wavelength 365 nm, output 80 mW / cm) ２ Using ), apply 2.0 J / cm² to the coated film. ２ Irradiate the material to form a film. Peel the film from the separator film, cut it into 5 cm squares, and use it as a sample. Measure the thickness of the sample with a micrometer. Measure five points on the film and take the average value as the sample thickness. As a photoinitiator, for example, 1-hydroxycyclohexyl phenyl ketone (Omnirad 184 (IGM Resins B.V.)) can be used. (Measurement) Perform multiple measurements using a dielectric property measuring device (split cylinder resonator (e.g., EM Lab Co., Ltd. "CR-710")) and adopt the average value. The number of measurements may be, for example, three.

[0047] <(meth)acrylic polymer> In some embodiments, the (meth)acrylic polymer includes a structural unit represented by the following formula (P1).

[0048] In the formula, C independently represents a group represented by the following formula (P1-1), B independently represents an alkyl group having 1 to 3 carbon atoms, and X and Y independently represent a single bond or a double bond. m, n, s, and t independently represent a number of 0 or more, m and n satisfy 1 ≤ m + n, and s and t satisfy 1 < s + t.

[0049]

[0050] In the formula, R represents a hydrogen atom or a methyl group, the dashed line indicates a bonding site with a carbon atom in formula (P1), and the asterisk (*) indicates a bonding site with another structural unit. "Carbon atom in formula (P1)" refers to a carbon atom included in a ring structure (the structure represented by formula (M1-1)).

[0051] The (meth)acrylic polymer may contain only one structural unit (P1) or multiple structural units. When the (meth)acrylic polymer contains multiple structural units (P1), m, n, s, and t are the average values ​​of the multiple structural units. The (meth)acrylic polymer may further contain other structural units.

[0052] In some embodiments, the structural unit (P1) includes a structural unit represented by the following formula (P0).

[0053] In the formula, C represents the group represented by formula (P1-1), B independently represents an alkyl group having 1 to 3 carbon atoms, and X and Y independently represent a single bond or a double bond.

[0054] Structural unit (P1) may be a structural unit derived from (meth)acrylic acid ester (M1), and the group represented by formula (P1-1) may be a group derived from A in (meth)acrylic acid ester (M1). Structural unit represented by formula (P0) may be a structural unit derived from (meth)acrylic acid ester (M0), and the group represented by formula (P1-1) may be a group derived from A in (meth)acrylic acid ester (M0). The explanations, examples, bond positions, preferred embodiments, etc., of the symbols in (meth)acrylic acid esters (M1) and (M0) can be applied to the symbols in structural units (P1) and (P0).

[0055] The content of the structural unit represented by formula (P0) may be, for example, 50 to 100 mol%, 70 to 100 mol%, or 80 to 100 mol%, based on structural unit (P1), from the viewpoint of improving heat resistance and, if necessary, reducing dielectric constant and dielectric loss tangent. The content of the structural unit represented by formula (P0) may be, for example, 50 to 100 mol%, 80 to 100 mol%, or 90 to 100 mol%, based on structural units having a cyclic structure, from the viewpoint of improving heat resistance and, if necessary, reducing dielectric constant and dielectric loss tangent. Examples of structural units having a cyclic structure include structural units having an aromatic ring and structural units having an alicyclic hydrocarbon group.

[0056] In a preferred embodiment, the structural unit (P1) includes a structural unit represented by the following formula (P2).

[0057] In the formula, R represents a hydrogen atom or a methyl group, and * represents a bonding site with another structural unit.

[0058] In a preferred embodiment, the structural unit (P1) includes a structural unit represented by the following formula (P3).

[0059] In the formula, R represents a hydrogen atom or a methyl group, and * represents a bonding site with another structural unit.

[0060] The method for producing a (meth)acrylic polymer containing structural unit (P1) is not particularly limited. For example, it can be produced by a polymerization reaction using (meth)acrylic acid ester (M1) and optionally any monomer as raw materials. The monomer may be a compound having a radically polymerizable carbon-carbon unsaturated bond. The (meth)acrylic polymer containing structural unit (P1) may be a homopolymer or a copolymer. A polymerization initiator may be used for polymerization.

[0061] The (meth)acrylic polymer may be, for example, a polymer comprising a structural unit (P1) and a structural unit derived from any monomer, and preferably a polymer comprising a structural unit (P1) and a structural unit derived from a compound having a radically polymerizable carbon-carbon unsaturated bond (except for (meth)acrylic acid ester (M1)). In this disclosure, "compound having a radically polymerizable carbon-carbon unsaturated bond," "(meth)acrylic acid ester compound," and "monomer having a (meth)acryloyl group" are compounds that do not fall under (meth)acrylic acid ester (M1).

[0062] When the (meth)acrylic polymer contains structural units (P1) and structural units derived from any monomer, the content of structural units (P1) may be, for example, 1 to 99 mol%, 10 to 50 mol%, or 20 to 40 mol%, based on the total structural units in the (meth)acrylic polymer, from the viewpoint of balancing the effect of structural units (P1) and the effect of structural units derived from any monomer.

[0063] When the (meth)acrylic polymer contains structural units (P1) and structural units derived from compounds having radically polymerizable carbon-carbon unsaturated bonds, the content of structural units (P1) may be, for example, 5 mol% or more, 10 mol% or more, or 20 mol% or more, based on the total of structural units (P1) and structural units derived from compounds having radically polymerizable carbon-carbon unsaturated bonds, from the viewpoint of obtaining sufficient effects from structural units (P1). The content of structural units (P1) may be, for example, 60 mol% or less, 50 mol% or less, or 40 mol% or less, from the viewpoint of obtaining sufficient effects from structural units derived from compounds having radically polymerizable carbon-carbon unsaturated bonds. The content of structural units (P1) may be, for example, 5 to 60 mol%, 10 to 50 mol%, or 20 to 40 mol%.

[0064] Examples of arbitrary monomers include olefin compounds such as ethylene, propylene, butadiene, isoprene, dimethylbutadiene, chloroprene, and 1,3-pentadiene; (meth)acrylic acid ester compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tetra(meth)acrylate, and bisphenol A diglycidyl ether di(meth)acrylate (excluding (meth)acrylic acid ester (M1)); and (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, etc. Examples include carboxyl group-containing vinyl compounds; ester group-containing vinyl compounds such as vinyl acetate and vinyl propionate; halogen-containing vinyl compounds such as vinyl chloride and vinylidene chloride; nitrile group-containing vinyl compounds such as acrylonitrile and methacrylonitrile; amide group-containing vinyl compounds such as acrylamide, methacrylamide, N-methylolacrylamide, and N-methylolmethacrylamide; maleimide compounds such as maleimide, N-phenylmaleimide, and 4,4'-diphenylmethanebismaleimide; and other nitrogen-containing vinyl compounds such as N-vinylpyrrolidone, 1-vinylimidazole, and vinylcarbazole.

[0065] The ratio of (meth)acrylic acid ester (M1) used when synthesizing (meth)acrylic polymers may be, for example, 1 to 100 mol% based on the total amount of monomer used. When using any monomer, the ratio of (meth)acrylic acid ester (M1) may be, for example, 1 to 99 mol%, 10 to 50 mol%, or 20 to 40 mol%, based on the total amount of monomer used.

[0066] The (meth)acrylic polymer may be a polymer comprising, for example, a structural unit (P1) and a structural unit derived from a monomer having a (meth)acryloyl group (excluding (meth)acrylic acid ester (M1)). Further examples of monomers having a (meth)acryloyl group are listed below. The monomer having a (meth)acryloyl group may be, for example, a monofunctional (meth)acrylate. Specifically, alkyl(meth)acrylates having C1-C18 alkyl groups such as (meth)acrylic acid; (meth)acrylamide; (meth)acryloylmorpholine; methyl(meth)acrylate, ethyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate, tert-butyl(meth)acrylate, n-pentyl(meth)acrylate, n-hexyl(meth)acrylate, n-octyl(meth)acrylate, isooctyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, isodecyl(meth)acrylate, n-dodecyl(meth)acrylate (lauryl(meth)acrylate), stearyl(meth)acrylate; (meth)acrylates having aromatic rings such as benzyl(meth)acrylate and phenoxyethyl(meth)acrylate; cyclohexyl(meth)acrylate, isobornyl(meth)acrylate Examples include (meth)acrylates having alicyclic hydrocarbon groups such as acrylate and dicyclopentanyl (meth)acrylate; tetrahydrofurfuryl (meth)acrylate; (meth)acrylamide derivatives such as N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, and N-hydroxyethyl (meth)acrylamide; (meth)acrylates having isocyanate groups such as 2-(2-methacryloyloxyethyl oxy)ethyl isocyanate and 2-(meth)acryloyloxyethyl isocyanate; alkylene glycol chain-containing (meth)acrylates; and (meth)acrylates having polar groups such as hydroxyl groups, amino groups, carboxyl groups, cyano groups, carbonyl groups, and nitro groups.

[0067] When the (meth)acrylic polymer is a polymer containing a structural unit (P1) and a structural unit derived from a monomer having a (meth)acryloyl group, the ratio of monomers having a (meth)acryloyl group may be, for example, 1 to 99 mol%, 50 to 90 mol%, or 60 to 80 mol%, based on the total amount of monomers used. The monomers having a (meth)acryloyl group preferably include an alkyl (meth)acrylate having one C1 to C18 alkyl group in the molecule. The ratio of alkyl (meth)acrylate having one C1 to C18 alkyl group in the molecule may be, for example, 50 to 100 mol%, 80 to 100 mol%, or 90 to 100 mol%, based on the total amount of monomers having a (meth)acryloyl group used.

[0068] In some embodiments, the alkyl (meth)acrylate having one C1-C18 alkyl group in the molecule may be monofunctional. The C1-C18 alkyl group may be substituted or unsubstituted. When the (meth)acrylic polymer includes a structural unit (P1) and a structural unit derived from a compound having a radically polymerizable carbon-carbon unsaturated bond, for example, the compound having a radically polymerizable carbon-carbon unsaturated bond includes a monofunctional (meth)acrylate. The monofunctional (meth)acrylate may include an alkyl (meth)acrylate having one C1-C18 alkyl group in the molecule. The ratio of the monofunctional (meth)acrylate may be 50-100 mol%, 80-100 mol%, or 90-100 mol%, based on the total amount of the compound having a radically polymerizable carbon-carbon unsaturated bond.

[0069] For example, radical polymerization initiators can be used as polymerization initiators. Examples of radical polymerization initiators include azo compounds and organic peroxides.

[0070] Examples of azo compounds include azobisisobutyronitrile (AIBN), 2,2'-azobis(2-methylisobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis(isobutyrate), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile).

[0071] Examples of organic peroxides include isobutyl peroxide, α,α'-bis(neodecanoylperoxyisopropyl)benzene, cumyl peroxyneodecanoate, di-n-propyl peroxydicarbonate, lauroyl peroxide, stearoyl peroxide, t-butyl peroxybenzoate, n-butyl-4,4-bis(t-butylperoxy)valerate, di-t-butylperoxyisophthalate, α,α'-bis(t-butylperoxyisopropyl)benzene, cumene hydroperoxide, t-hexyl hydroperoxide, and t-butyl hydroperoxide.

[0072] The amount of radical polymerization initiator used can be appropriately selected depending on the type of monomer, and may be a general amount. For example, the amount of radical polymerization initiator used is 0.1 to 5% by mass or 1 to 4% by mass, based on the total amount of monomer.

[0073] (Meth)acrylic polymers are preferably synthesized by solution polymerization using a solvent. The solvent is preferably an organic solvent, and more preferably a solvent in which the monomer dissolves. For example, methanol, ethanol, propanol, methyl cellosolve, cellosolve, acetone, acetylacetone, methyl ethyl ketone, methyl isobutyl ketone acetonitrile, hexane, benzene, toluene, dichloromethane, ethyl acetate, butyl acetate, chlorobenzene, dichlorobenzene, etc. There are no particular restrictions on the amount of solvent used; an appropriate amount should be used from the viewpoint of polymerization rate, molecular weight of the polymerized (meth)acrylic polymer, etc.

[0074] There are no particular restrictions on the temperature when synthesizing (meth)acrylic polymers, and it is best to determine the temperature by considering the type of monomer used, the boiling point of the solvent, the half-life temperature of the polymerization initiator, etc. For example, when polymerizing using azobisisobutyronitrile (AIBN) as the polymerization initiator, the reaction temperature is preferably 50 to 80°C.

[0075] When (meth)acrylic polymers are obtained by solution polymerization, the (meth)acrylic polymer can be removed as is as a polymer solution after the reaction, or it can be purified by precipitation. For example, by adding the polymer solution after the reaction to a poor solvent for the (meth)acrylic polymer dropwise, the (meth)acrylic polymer can be obtained as a precipitate, thereby removing any unreacted monomers remaining in the polymer solution.

[0076] The number-average molecular weight (Mn) of the (meth)acrylic polymer is preferably 10,000 to 500,000. When the number-average molecular weight is 10,000 or more, the heat resistance tends to improve. On the other hand, when the number-average molecular weight is 100,000 or less, it tends to prevent the viscosity from becoming too high. From these viewpoints, the number-average molecular weight is more preferably 20,000 to 200,000, and even more preferably 30,000 to 150,000.

[0077] The weight-average molecular weight (Mw) of the (meth)acrylic polymer is preferably 30,000 to 1,000,000. When the weight-average molecular weight is 30,000 or higher, the heat resistance tends to improve. On the other hand, when the weight-average molecular weight is 1,000,000 or lower, it tends to prevent the viscosity from becoming too high. From these viewpoints, the weight-average molecular weight is more preferably 50,000 to 800,000, and even more preferably 100,000 to 500,000.

[0078] The polydispersity (Mw / Mn) of the (meth)acrylic polymer is preferably 1.0 to 5.0. When the polydispersity is 5.0 or less, it tends to be possible to form a molded article with stable properties such as glass transition temperature and dielectric properties. From the above viewpoint, the polydispersity is more preferably 1.0 to 4.0, and even more preferably 1.0 to 3.0.

[0079] In this disclosure, the number-average molecular weight and weight-average molecular weight of the (meth)acrylic polymer can be determined by gel permeation chromatography (GPC) and converted from a calibration curve using standard polystyrene. Specifically, they can be measured according to the conditions described in the examples.

[0080] The glass transition temperature (Tg) of the (meth)acrylic polymer (P1) may be, for example, 80°C or higher, 110°C or higher, 140°C or higher, or 170°C or higher. When the glass transition temperature is 110°C or higher, the heat resistance of the molded article tends to improve. In particular, the dielectric properties tend to stabilize in the high-temperature range in the dielectric layer. The glass transition temperature may be, for example, 300°C or lower. When the glass transition temperature exceeds 300°C, thermal decomposition tends to start before the glass transition.

[0081] The (meth)acrylic polymer may have a relative permittivity (Dk) at a frequency of 10 GHz and 25°C of, for example, 2.0 or higher, 2.3 or higher, 2.5 or higher, or 2.7 or higher. In particular, when used as a dielectric layer in a capacitor, a relative permittivity (Dk) of 2.3 or higher is preferred. The relative permittivity (Dk) may be, for example, 4.0 or lower. The (meth)acrylic polymer may have a dielectric loss tangent (Df) at a frequency of 10 GHz and 25°C of, for example, 0.020 or lower, 0.015 or lower, 0.010 or lower, or 0.005 or lower. In particular, when a molded body is used as a dielectric layer in a capacitor, a dielectric loss tangent (Df) of 0.010 or lower is preferred. The dielectric loss tangent (Df) may be, for example, 0.0001 or higher.

[0082] The preparation of samples for measuring relative permittivity and dielectric loss tangent shall be carried out according to the following method. The measurement method is as described above. (Sample preparation) A (meth)acrylic polymer solution is uniformly applied to a separator film and the film thickness is adjusted to approximately 200 to 500 μm. The applied film is dried to form a film. The film is peeled from the separator film and cut into 5 cm squares to be used as samples. The thickness of the sample is measured with a micrometer. Five points on the film are measured and the average value is taken as the thickness of the sample.

[0083] <Molding Material> In some embodiments, the molding material contains at least one selected from the group consisting of (meth)acrylic polymers containing (meth)acrylic acid ester (M1) and structural units (P1). The molding material is a material used to obtain a molded article. Depending on the application, the molding material may contain any components such as additives, other monomers, and other polymers. Examples of additives include antioxidants, ultraviolet absorbers, light stabilizers, polymerization inhibitors, and surfactants. The total content of at least one selected from the group consisting of (meth)acrylic polymers containing (meth)acrylic acid ester (M1) and structural units (P1) may be 80 to 100% by mass, 90 to 100% by mass, or 95 to 100% by mass, based on the molding material.

[0084] <Applications> (Meth)acrylic polymers containing (meth)acrylic acid ester (M1) and structural unit (P1), and molding materials can be used as resist materials, coating materials, heat-resistant materials, dielectric materials, adhesives, sealants, inks, paints, building materials, optical materials, electronic component materials, 3D printing materials, etc. In some embodiments, the 3D printing material contains at least one selected from the group consisting of (meth)acrylic acid ester (M1) and structural unit (P1) (meth)acrylic polymer. In some other embodiments, the inkjet ink material contains at least one selected from the group consisting of (meth)acrylic acid ester (M1) and structural unit (P1) (meth)acrylic polymer.

[0085] <Curable Composition> In some embodiments, the curable composition contains at least one selected from the group consisting of (meth)acrylic acid ester (M1), (meth)acrylic polymer containing structural unit (P1), molding material, 3D printing material, and inkjet ink material, and a polymerization initiator. Depending on the application, the curable composition may contain any components such as solvents, additives, other monomers, and other polymers. The solvent is preferably an organic solvent, and specifically, the solvents listed as solvents used in the synthesis of (meth)acrylic polymers can be used. Examples of additives include antioxidants, ultraviolet absorbers, light stabilizers, polymerization inhibitors, and surfactants.

[0086] The polymerization initiator may be a thermal polymerization initiator or a photopolymerization initiator. Examples of thermal polymerization initiators include azo compounds and peroxides. Specific examples are as described above. Examples of photopolymerization initiators include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, and benzophenone-based photopolymerization initiators.

[0087] Examples of benzoin ether-based photopolymerization initiators include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one, and anisole methyl ether. Examples of acetophenone-based photopolymerization initiators include 1-hydroxycyclohexylphenyl ketone (e.g., Omnirad 184 (IGM Resins B.V.)), 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and methoxyacetophenone. Examples of benzophenone-based photopolymerization initiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone.

[0088] The total content of (meth)acrylic polymer containing (meth)acrylic acid ester (M0) and structural unit (P1) may be 80% by mass or more, 90% by mass or more, or 95% by mass or more, based on the curable composition. Considering the content of polymerization initiators and additives used as needed, the upper limit is less than 100% by mass.

[0089] The curable composition may be, for example, a 3D printing composition. In some embodiments, the 3D printing composition contains a 3D printing material. A 3D printing composition is a composition used for molding using 3D printing technology and is generally broadly classified into resin-based compositions and inorganic powder-based compositions. In resin-based compositions, monofunctional acrylic monomers such as acryloylmorpholine (ACMO) and isobornyl acrylate (IBOA) may be used as diluent monomers to reduce the viscosity of the composition. A 3D printing composition may contain, for example, a 3D printing material, a polymerization initiator, and optionally fillers, colorants, arbitrary monomers, arbitrary polymers, etc. The properties required of a 3D printing composition include excellent heat resistance of the molded object, low viscosity, and not degrading the physical properties of the molded object. Depending on the application, low dielectric and low dielectric loss tangent may also be required. The 3D printing composition according to this disclosure is a preferred composition because it contains a (meth)acrylic acid ester (M1) and a ring structure in which the structural unit (P1) is substituted with an alkyl group, thereby improving these properties.

[0090] The 3D printing method using the 3D printing composition is not particularly limited. For example, vat photopolymerization (VPP) can be used, and among these, the free-surface VPP method (also called stereolithography) is preferred. In the free-surface VPP method, the 3D printing composition is cured mainly by irradiating it with 355 nm UV laser light. Another example is material jetting (MJT). These methods make it easy to prototype industrial products and verify their shapes.

[0091] The curable composition may be, for example, an inkjet ink. In some embodiments, the inkjet ink contains an inkjet ink material. The inkjet ink may contain the inkjet ink material as the main component of a UV-curable ink. The inkjet ink contains, for example, a (meth)acrylic acid ester represented by formula (M1), a polymerization initiator, a colorant as needed, an arbitrary monomer, a polymerization inhibitor, a solvent, etc. The arbitrary monomer may be a monofunctional monomer or a polyfunctional monomer, and should be selected according to the application of the ink. A polymerization inhibitor may be added to prevent the ink from hardening during storage of the inkjet ink or when the print head is filled. The properties required of an inkjet ink include excellent heat resistance of the printed layer, as well as not degrading the physical properties of the printed layer. Depending on the application, low dielectric and low dielectric loss tangent may also be required. The inkjet ink according to this disclosure contains a ring structure in which the (meth)acrylic acid ester (M1) is substituted with an alkyl group, so these properties can be improved, and effects such as shortening the printing time and being able to easily print on three-dimensional objects, thick layers, films, substrates, etc. can also be obtained.

[0092] <Molded Article> In some embodiments, the molded article can be obtained using at least one selected from the group consisting of (meth)acrylic acid ester (M1), (meth)acrylic polymer containing structural units (P1), molding material, 3D printing material, inkjet ink material, and curable composition. The molded article may be a cured product, a molded product, a printed layer, etc. The shape of the molded article is not particularly limited and may be a shape appropriate for the application. Examples include film, plate, membrane, layer, granular, etc. The applications of the molded article are not particularly limited and include resist layers, coating layers, dielectric layers, adhesive layers, tack layers, optical components, etc.

[0093] <Electronic Components> In some embodiments, electronic components can be obtained using at least one selected from the group consisting of (meth)acrylic acid ester (M1), (meth)acrylic polymer containing structural units (P1), molding materials, 3D printing materials, inkjet ink materials, and curable compositions. In some embodiments, electronic components include molded bodies. Examples of electronic components include active elements or components such as diodes, transistors, integrated circuits, and relays; passive elements or components such as resistors, capacitors, and coils; connectors, support members, terminals, and switches; devices having one or more selected from these; and modules having one or more selected from these. Devices and modules may have support members. Examples of support members include lead frames, wired tape carriers, wiring boards, glass, silicon wafers, and organic substrates. The electronic component includes a molded body obtained using at least one selected from the group consisting of (meth)acrylic acid ester (M1), (meth)acrylic polymer containing structural unit (P1), molding material, 3D printing material, inkjet ink material, and curable composition, for example, as a resist layer, coating layer, dielectric layer, protective layer, adhesive layer, tack layer, optical member, support member, etc.

[0094] <Examples of Embodiments> The present invention includes the following embodiments. The present invention is not limited to the following embodiments. [1] A (meth)acrylic acid ester represented by the above formula (M1). [2] The (meth)acrylic acid ester according to [1], comprising the (meth)acrylic acid ester represented by the above formula (M0). [3] The (meth)acrylic acid ester according to [2], wherein the content of the (meth)acrylic acid ester represented by the above formula (M0) is 80 to 100 mol% based on the (meth)acrylic acid ester (M1). [4] The (meth)acrylic acid ester according to any one of [1] to [3], comprising the (meth)acrylic acid ester represented by the above formula (M2). [5] The (meth)acrylic acid ester according to any one of [1] to [4], comprising the (meth)acrylic acid ester represented by the above formula (M3). [6] A (meth)acrylic polymer comprising a structural unit represented by the above formula (P1). [7] The (meth)acrylic polymer according to [6], wherein the structural unit represented by formula (P1) includes the structural unit represented by formula (P0) described above. [8] The (meth)acrylic polymer according to [7], wherein the content of the structural unit represented by formula (P0) is 80 to 100 mol% based on the structural unit represented by formula (P1). [9] The (meth)acrylic polymer according to [7] or [8], wherein the content of the structural unit represented by formula (P0) is 90 to 100 mol% based on the structural unit having a cyclic structure.

[10] The (meth)acrylic polymer according to any one of [6] to [9], wherein the content of the structural unit represented by formula (P1) is 20 to 40 mol% based on the total structural units.

[11] The (meth)acrylic polymer according to any one of [6] to

[10] , further comprising structural units derived from a compound having a radically polymerizable carbon-carbon unsaturated bond.

[12] The (meth)acrylic polymer according to

[11] , wherein the content of the structural unit represented by formula (P1) is 5 to 60 mol% based on the sum of the structural unit represented by formula (P1) and the structural unit derived from the radically polymerizable carbon-carbon unsaturated bond compound.

[13] The (meth)acrylic polymer according to

[11] or

[12] , wherein the compound having a radically polymerizable carbon-carbon unsaturated bond comprises a monofunctional (meth)acrylate.

[14] The (meth)acrylic polymer according to

[13] , wherein the monofunctional (meth)acrylate comprises an alkyl (meth)acrylate having one C1 to C18 alkyl group in the molecule.

[15] The (meth)acrylic polymer according to

[13] or

[14] , wherein the ratio of the monofunctional (meth)acrylate is 90 to 100 mol% based on the total amount of the compound having a radically polymerizable carbon-carbon unsaturated bond.

[16] The (meth)acrylic polymer according to

[14] or

[15] , wherein the ratio of the alkyl (meth)acrylate having one C1 to C18 alkyl group in the molecule is 90 to 100 mol% based on the total amount of the monomer having a (meth)acryloyl group.

[17] A molding material containing at least one selected from the group consisting of (meth)acrylic acid esters described in any of [1] to [5] and (meth)acrylic polymers described in any of [6] to

[16] .

[18] The molding material according to

[17] , wherein the total content of (meth)acrylic acid esters represented by formula (M1) and (meth)acrylic polymers containing structural units represented by formula (P1) is 90 to 100% by mass, based on the molding material.

[19] A 3D printing material containing at least one selected from the group consisting of (meth)acrylic acid esters described in any of [1] to [5] and (meth)acrylic polymers described in any of [6] to

[16] .

[20] An inkjet ink material containing at least one selected from the group consisting of (meth)acrylic acid esters described in any of [1] to [5] and (meth)acrylic polymers described in any of [6] to

[16] .

[21] A curable composition comprising at least one selected from the group consisting of (meth)acrylic acid ester according to any one of [1] to [5], (meth)acrylic polymer according to any one of [6] to

[16] , molding material according to any one of

[17] and

[18] , 3D printing material according to

[19] , and inkjet ink material according to

[20] , and a polymerization initiator.

[22] The curable composition according to

[21] , wherein the total content of the (meth)acrylic acid ester (M0) and the (meth)acrylic polymer containing the structural unit represented by formula (P1) is 90% by mass or more, based on the curable composition.

[23] A molded article obtained using at least one selected from the group consisting of the (meth)acrylic acid ester according to any one of [1] to [5], the (meth)acrylic polymer according to any one of [6] to

[16] , the molding material according to any one of

[17] and

[18] , the 3D printing material according to

[19] , the inkjet ink material according to

[20] , and the curable composition according to any one of

[21] and

[22] .

[24] An electronic component obtained using at least one selected from the group consisting of the (meth)acrylic acid ester described in any of [1] to [5], the (meth)acrylic polymer described in any of [6] to

[16] , the molding material described in any of

[17] and

[18] , the 3D printing material described in

[19] , the inkjet ink material described in

[20] , and the curable composition described in any of

[21] and

[22] , or comprising the molded article described in

[23] .

[0095] The disclosures of this application are relating to the subject matter described in Japanese Patent Application No. 2024-196852, filed on November 11, 2024, all of which are incorporated herein by reference.

[0096] Embodiments of the present invention will be described with reference to examples. Embodiments of the present invention are not limited to the following examples.

[0097] <Synthesis and Evaluation of (Meth)acrylic Acid Esters> [Example 1] (Synthesis of Acrylic Acid Ester 1) (1) Synthesis of DMDCPD-OH A reaction vessel equipped with a stirrer, thermometer, and condenser was placed under a nitrogen atmosphere and 1,000 g (6.24 mol) of dimethyldicyclopentadiene (DMDCPD) and 627.7 g (H) of a 20% by mass aqueous sulfuric acid solution were mixed. ２ SO ４A 1.28 mol solution was added and reacted at 80-100°C for 7 hours. After cooling, the organic layer and aqueous layer were separated. The organic layer was then washed multiple times with a basic aqueous solution. Concentration and distillation were performed to obtain 221 g of the target product, DMDCPD-OH. １ ¹H-NMR confirmed the appearance of a peak originating from the introduced hydroxyl group and the disappearance of the peak originating from the norbornene ring-side double bond. Furthermore, it was confirmed that the peak originating from the cyclopentene ring-side double bond was present in approximately equal amounts to the hydroxyl group peak.

[0098] (2) Synthesis of hydrogenated DMDCPD-OH by hydrogenation reaction 315 g of DMDCPD-OH synthesized in (1) and 0.221 g of Pd / C catalyst (Pd 5 mass%) were charged into a stainless steel high-pressure reaction vessel equipped with a stirrer and thermocouple. The reaction was carried out by replacing the atmosphere inside the reaction vessel with a hydrogen atmosphere, maintaining the pressure at 1.0 to 5.0 MPa, and maintaining the temperature of the reaction vessel at 50 to 100°C. The mixture after the reaction was filtered by suction to remove the catalyst and obtain 268 g of the target product, hydrogenated DMDCPD-OH. １ The disappearance of the peak originating from the double bond on the cyclopentene ring was confirmed by 1H-NMR.

[0099] (3) Synthesis of Acrylic Acid Ester 1 by Transesterification Reaction In a reaction vessel equipped with a stirrer, thermometer, air inlet tube, and rectification column, 100 g (0.550 mol) of hydrogenated DMDCPD-OH synthesized in (2), 555 g (5.55 mol) of ethyl acrylate, and 0.032 g (0.258 mmol) of 4-methoxyphenol were charged, and the mixture was stirred and heated under reflux while blowing in dry air. 1.60 g (5.63 mmol) of titanium(IV) tetraisopropoxide (TPT) was charged, and the pressure in the system was adjusted to approximately 50 kPa so that the temperature of the liquid in the flask was 80-85°C. At the end of the reaction, the reaction mixture was cooled, the pressure in the reaction vessel was returned to atmospheric pressure, and the organometallic catalyst was deactivated. Subsequently, liquid-liquid separation was performed to concentrate the organic layer, and filtration was carried out to obtain 66 g of the target product, acrylic acid ester 1 (represented by formula (M1), where A is an acryloyloxy group, B is a methyl group, m+n=1, and s+t=1.8). １¹H-NMR confirmed the appearance of peaks originating from the introduced vinyl and ester groups. Acrylic acid ester 1 contained 80-100 mol% acrylic acid ester (M2) (where R is a hydrogen atom). The position and amount of introduced acryloyloxy groups were determined in the above (1) synthesis of DMDCPD-OH. １ Based on 1H-NMR, n=0 and m=1, i.e., n+m=1. Furthermore, the amount of methyl group introduced was: １ The difference in hydrogen peak positions on the carbon atom bonded to the ether group (oxygen) of the acryloyloxy group was confirmed and calculated using 1H-NMR.

[0100] [Example 2] (Synthesis of methacrylic acid ester 1) (1) Synthesis of DMDCPD-OH and (2) Synthesis of hydrogenated DMDCPD-OH by hydrogenation reaction Hydrogenated DMDCPD-OH was obtained in the same manner as in Example 1.

[0101] (3) Synthesis of methacrylate ester 1 by transesterification reaction In a reaction vessel equipped with a stirrer, thermometer, air inlet tube and rectification column, 100 g (0.550 mol) of hydrogenated DMDCPD-OH synthesized in (2), 555 g (5.55 mol) of methyl methacrylate and 0.032 g (0.258 mmol) of 4-methoxyphenol were charged, and the mixture was stirred and heated under reflux while blowing in dry air. 1.60 g (5.63 mmol) of titanium(IV) tetraisopropoxide (TPT) was charged, and the pressure in the system was adjusted to approximately 50 kPa so that the temperature of the liquid in the flask was 80-85°C. At the end of the reaction, the reaction mixture was cooled, the pressure in the reaction vessel was returned to atmospheric pressure, and the organometallic catalyst was deactivated. Subsequently, liquid-liquid separation was performed to concentrate the organic layer, and filtration was carried out to obtain 80 g of the target product, methacrylic acid ester 1 (represented by formula (M1), where A is a methacryloyloxy group, B is a methyl group, m+n=1, and s+t=1.8). １ ¹H-NMR confirmed the appearance of peaks originating from the introduced vinyl and ester groups. Methacrylic acid ester 1 contained 80-100 mol% acrylic acid ester (M2) (where R is a methyl group).

[0102] [Evaluation] The relative permittivity and dielectric loss tangent of acrylic acid ester 1 obtained in Example 1, methacrylic acid ester 1 obtained in Example 2, and the (meth)acrylic acid esters of Reference Examples 1 and 2 were measured according to the following method. The results are shown in Table 1. In addition, methacrylic acid ester 1 obtained in Example 2 was polymerized to obtain a polymer, and the molecular weight, glass transition temperature, etc. were measured. The results are shown in Table 2 as Example 3.

[0103] (Relative permittivity (Dk, ε) ｒ ), dielectric loss tangent (Df, tanδ) A split-cylinder resonator was used to measure dielectric properties. The measurement conditions and methods are as follows: (Measurement conditions) Measurement equipment: Split-cylinder resonator CR-710 (EM Lab Co., Ltd.) USB vector network analyzer P5003A (Keysight Technologies Inc.) Measurement frequency: 10 GHz Temperature: Room temperature (25°C) (Sample preparation) To (meth)acrylic acid ester, 3% by mass of a photopolymerization initiator (Omnirad 184, IGM Resins B.V. Inc.) was added relative to the mass of the (meth)acrylic acid ester, and the mixture was stirred until homogeneous to obtain a mixture. The mixture was uniformly coated onto a separator film, and the film thickness was adjusted to approximately 200-500 μm. UV lamp (wavelength 365 nm, output 80 mW / cm) ２ Using ), apply 2.0 J / cm² to the coated film. ２ The film was irradiated with [a specific light source]. The resulting film was peeled from the separator film, and a 5 cm square polymer film was cut out to serve as a sample. The thickness of the sample was measured with a micrometer. Five points on the film were measured, and the average value was taken as the sample thickness. (Measurement method) The sample was inserted into the sample insertion area of ​​a dielectric measuring device (split cylinder resonator, 10 GHz, EM Lab Co., Ltd.) and fixed in place. Multiple measurements were taken, and the average values ​​were used as the measured values ​​for relative permittivity and dielectric loss tangent. The measured values ​​in Table 1 are the average values ​​calculated from three measurements.

[0104]

[0105] As shown in Table 1, by using (meth)acrylic acid ester (M1), we were able to obtain a film with low dielectric constant and dielectric loss tangent.

[0106] <Synthesis and Evaluation of (Meth)acrylic Polymers> [Example 3] (Polymerization of Methacrylic Ester 1) 20 g (0.0806 mol) of Methacrylic Ester 1 obtained in Example 2, 80 g of ethyl acetate, and 0.008 g (0.0488 mmol) of azobisisobutyronitrile (AIBN) were placed in a reactor under a nitrogen atmosphere, and the reaction was carried out at a rotation speed of 130 min while maintaining the reaction temperature at 67-68°C. －１ The mixture was stirred. After 7 hours from the start of the reaction, the reaction was stopped, and reprecipitation was performed using methanol as a poor solvent. The eluate was vacuum dried and the solvent was removed to obtain 3.07 g of the target methacrylic polymer.

[0107] [Example 4] (Polymerization of Acrylic Acid Ester 1 and Methyl Methacrylate) 20 g (0.0855 mol) of Acrylic Acid Ester 1 obtained in Example 1, 20 g (0.200 mol) of methyl methacrylate, 80 g of ethyl acetate, and 0.008 g (0.0488 mmol) of AIBN were placed in a reactor under a nitrogen atmosphere, and the reaction was carried out at a rotation speed of 130 min while maintaining the reaction temperature at 67-68°C. －１ The mixture was stirred. The reaction was stopped after 9 hours, and reprecipitation was performed using methanol as a poor solvent. The eluate was vacuum dried and the solvent was removed to obtain 4.79 g of the target (meth)acrylic polymer.

[0108] [Comparative Example 1] (Polymerization of dicyclopentanyl methacrylate) 40 g (0.1816 mol) of dicyclopentanyl methacrylate, 80 g of toluene, and 0.008 g (0.0488 mmol) of AIBN were placed in a reactor under a nitrogen atmosphere, and the reaction was carried out at a rotation speed of 130 min while maintaining the reaction temperature at 67-68°C. －１ The mixture was stirred. The reaction was stopped after 6 hours, and reprecipitation was performed using methanol as a poor solvent. The eluate was vacuum dried and the solvent was removed to obtain the target polymer.

[0109] [Evaluation] The molecular weight, glass transition temperature, etc., of the acrylic polymer obtained in Example 3, the (meth)acrylic polymer obtained in Example 4, and the polymer obtained in Comparative Example 1 were measured according to the following method. The results are shown in Table 2.

[0110] (Number average molecular weight (Mn), weight average molecular weight (Mw), polydispersity (Mw / Mn)) Gel permeation chromatography (GPC) was used for molecular weight measurement. The measurement conditions and methods are as follows: (Measurement conditions) Column: GL-A130-S, GL-A150-S, GL-A160-S (Hitachi High-Tech Science Co., Ltd.) Mobile phase: Tetrahydrofuran (THF) Flow rate: 1,000 mL / min Detector: RI detector "HITACHI Chromaster 5450" (Hitachi High-Tech Science Co., Ltd.) Column temperature: 35°C (Sample preparation) 0.04 g of (meth)acrylic polymer and 3.96 g of tetrahydrofuran (THF) were mixed to prepare a 1% by mass THF solution. After passing the THF solution through a Teflon membrane filter, 1.5 mL of the obtained sample was packed into a vial. (Molecular weight calculation) A calibration curve was created using the standard polystyrene "TSKgel standard Polystyrene Oligomer kit" (Tosoh Corporation), and the molecular weight of the sample was calculated.

[0111] (Glass transition temperature (Tg)) A differential scanning calorimeter (DSC) was used to measure the glass transition temperature. The measurement conditions and method were as follows: 5 to 10 mg of (meth)acrylic polymer was packed into an aluminum container and placed in the measuring instrument "DSC-60APlus" (Shimadzu Corporation). An empty container was used as a reference. The measuring instrument was maintained under a nitrogen atmosphere. Then, to prepare the sample, it was heated to 200 to 230°C at a rate of 10°C / min, held for 10 minutes, and then cooled to 30°C. Next, after holding the instrument at 30°C until it stabilized, the measurement was performed by heating it to 200 to 230°C at a rate of 10°C / min. A baseline shift was detected in the DSC curve, so it was determined that a glass transition had occurred, and the midpoint glass transition temperature was read.

[0112]

[0113] As shown in Table 2, the glass transition temperature of the (meth)acrylic polymer could be increased by using (meth)acrylic ester (M1). The glass transition temperature of polymethyl methacrylate, obtained by polymerizing methyl methacrylate alone, is approximately 105°C. By using a (meth)acrylic polymer with a high glass transition temperature, it is possible to manufacture molded articles with excellent heat resistance.

Claims

1. (Meth)acrylic acid ester represented by the following formula (M1). (In the formula, A independently represents a (meth)acryloyloxy group, B independently represents an alkyl group having 1 to 3 carbon atoms, X and Y independently represent a single bond or a double bond, m, n, s, and t independently represent a number of 0 or more, m and n satisfy 1 ≤ m + n, and s and t satisfy 1 < s + t.) 2. The (meth)acrylic acid ester according to claim 1, comprising a (meth)acrylic acid ester represented by the following formula (M0). (In the formula, A represents a (meth)acryloyloxy group, B independently represents an alkyl group having 1 to 3 carbon atoms, and X and Y independently represent a single bond or a double bond.) 3. The (meth)acrylic acid ester according to claim 2, wherein the content of the (meth)acrylic acid ester represented by formula (M0) is 80 to 100 mol% based on the (meth)acrylic acid ester (M1).

4. The (meth)acrylic acid ester according to any one of claims 1 to 3, comprising a (meth)acrylic acid ester represented by the following formula (M2). (In the formula, R represents a hydrogen atom or a methyl group.) 5. The (meth)acrylic acid ester according to any one of claims 1 to 4, comprising a (meth)acrylic acid ester represented by the following formula (M3). (In the formula, R represents a hydrogen atom or a methyl group.) 6. A (meth)acrylic polymer containing a structural unit represented by the following formula (P1). (In the formula, C independently represents a group represented by the following formula (P1-1), B independently represents an alkyl group having 1 to 3 carbon atoms, X and Y independently represent a single bond or a double bond, m, n, s and t independently represent a number of 0 or more, m and n satisfy 1 ≤ m + n, and s and t satisfy 1 < s + t.) (In the formula, R represents a hydrogen atom or a methyl group, the dashed line indicates a bond site with a carbon atom in formula (P1), and the asterisk (*) indicates a bond site with another structural unit.) 7. The (meth)acrylic polymer according to claim 6, wherein the structural unit represented by formula (P1) includes a structural unit represented by the following formula (P0). (In the formula, C represents the group represented by formula (P1-1), B independently represents an alkyl group having 1 to 3 carbon atoms, and X and Y independently represent a single bond or a double bond.) 8. The (meth)acrylic polymer according to claim 7, wherein the content of the structural unit represented by formula (P0) is 80 to 100 mol%, based on the structural unit represented by formula (P1).

9. The (meth)acrylic polymer according to claim 7 or 8, wherein the content of the structural unit represented by formula (P0) is 90 to 100 mol%, based on the structural unit having a cyclic structure.

10. The (meth)acrylic polymer according to any one of claims 6 to 9, wherein the content of the structural unit represented by formula (P1) is 20 to 40 mol% based on the total structural units.

11. The (meth)acrylic polymer according to any one of claims 6 to 10, further comprising structural units derived from a compound having a radically polymerizable carbon-carbon unsaturated bond.

12. The (meth)acrylic polymer according to claim 11, wherein the content of the structural unit represented by formula (P1) is 5 to 60 mol% based on the sum of the structural unit represented by formula (P1) and the structural unit derived from the radically polymerizable carbon-carbon unsaturated bond compound.

13. The (meth)acrylic polymer according to claim 11 or 12, wherein the radically polymerizable carbon-carbon unsaturated bond-containing compound comprises a monofunctional (meth)acrylate.

14. The (meth)acrylic polymer according to claim 13, wherein the monofunctional (meth)acrylate comprises an alkyl (meth)acrylate having one C1 to C18 alkyl group in the molecule.

15. The (meth)acrylic polymer according to claim 13 or 14, wherein the ratio of the monofunctional (meth)acrylate is 90 to 100 mol% based on the total amount of the compound having a radically polymerizable carbon-carbon unsaturated bond.

16. The (meth)acrylic polymer according to claim 14 or 15, wherein the ratio of alkyl (meth)acrylate having one C1 to C18 alkyl group in the molecule is 90 to 100 mol% based on the total amount of monomer having a (meth)acryloyl group.

17. A molding material containing at least one selected from the group consisting of a (meth)acrylic acid ester according to any one of claims 1 to 5 and a (meth)acrylic polymer according to any one of claims 6 to 16.

18. The molding material according to claim 17, wherein the total content of the (meth)acrylic acid ester represented by formula (M1) and the (meth)acrylic polymer containing the structural unit represented by formula (P1) is 90 to 100% by mass, based on the molding material.

19. A 3D printing material containing at least one selected from the group consisting of a (meth)acrylic acid ester according to any one of claims 1 to 5 and a (meth)acrylic polymer according to any one of claims 6 to 16.

20. An inkjet ink material comprising at least one selected from the group consisting of a (meth)acrylic acid ester according to any one of claims 1 to 5 and a (meth)acrylic polymer according to any one of claims 6 to 16.

21. A curable composition comprising at least one selected from the group consisting of a (meth)acrylic acid ester according to any one of claims 1 to 5, a (meth)acrylic polymer according to any one of claims 6 to 16, a molding material according to any one of claims 17 and 18, a 3D printing material according to claim 19, and an inkjet ink material according to claim 20, and a polymerization initiator.

22. The curable composition according to claim 21, wherein the total content of the (meth)acrylic ester (M0) and the (meth)acrylic polymer containing the structural unit represented by formula (P1) is 90% by mass or more, based on the curable composition.

23. A molded article obtained using at least one selected from the group consisting of a (meth)acrylic acid ester according to any one of claims 1 to 5, a (meth)acrylic polymer according to any one of claims 6 to 16, a molding material according to any one of claims 17 and 18, a 3D printing material according to claim 19, an inkjet ink material according to claim 20, and a curable composition according to any one of claims 21 and 22.

24. An electronic component comprising a molded article according to claim 23, obtained using at least one selected from the group consisting of a (meth)acrylic acid ester according to any one of claims 1 to 5, a (meth)acrylic polymer according to any one of claims 6 to 16, a molding material according to any one of claims 17 and 18, a 3D printing material according to claim 19, an inkjet ink material according to claim 20, and a curable composition according to any one of claims 21 and 22.

Images