Phenolic resins and their uses

Abstract

This invention provides a phenolic resin that not only possesses excellent storage stability but also exhibits excellent processability in the production of dielectric materials for metal-clad laminates. [Solution] A phenolic resin represented by the following formula (I), JPEG2026047034000007.jpg1994 In formula 1994, each Ar is an arylene having hydroxyl groups (multiple are possible), and each Ar may be the same or different; each R is a methylene; m1 and m2 are independent integers in the range of 0 to 4; n is greater than 0; when the phenol resin is characterized by gel permeation chromatography (GPC), the total area of ​​peaks representing the region where n is less than 5 is A, the total area of ​​peaks representing the region where n is 5 or more is B, and the ratio of B to A (B / A) is 0.35 to 1.32, phenol resin.

Description

Technical Field

[0001] The present invention provides a phenolic resin, particularly a phenolic resin having specific gel permeation chromatography (GPC) characteristics. The phenolic resin of the present invention has excellent storage stability and processability, and is particularly suitable for use in metal-clad laminates.

Background Art

[0002] A printed circuit board (PCB) can be used as a board for electronic devices, and various electronic components that can be electrically connected to each other can be mounted thereon in order to provide a stable circuit operating environment. The board of a general printed circuit board is a copper-clad laminate (CCL).

[0003] Usually, a copper-clad laminate can be produced by the following method: a thermosetting resin (phenolic resin, epoxy resin, etc.) is uniformly mixed with other additives, and these are dissolved or dispersed in a solvent to form a varnish; this varnish is impregnated into a reinforcing material (glass fiber cloth, etc.), and the impregnated reinforcing material is partially cured to a semi-cured state (i.e., B-stage) to obtain a prepreg; a certain number of layers of this prepreg are stacked, a metal foil is stacked on at least one outer surface of the stacked prepregs to form a laminate; and this laminate is hot-pressed (i.e., C-stage) to obtain a copper-clad laminate.

[0004] Examples of the thermosetting resins described above include phenolic resins, epoxy resins, and others. Among them, phenolic resins are widely used because they have excellent insulation properties and heat resistance. However, in order to ensure the quality stability of copper-clad laminates, it is required that the varnish formulated from the thermosetting resin has excellent storage stability, that is, phenomena such as crystallization and phase separation do not occur under long-term storage. However, phenolic resins generally have a problem of being easily crystallized and thus having poor storage stability.

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of the above, the present invention provides a phenolic resin that not only has excellent storage stability but also exhibits excellent processability in the production of dielectric materials for metal-clad laminates. As a result, no resin shortage occurs in the produced metal-clad laminates. [Means for solving the problem]

[0006] Therefore, the object of the present invention is a phenolic resin represented by the following formula (I),

[0007] [ka]

[0008] During the ceremony, Each Ar is an arylene having a hydroxyl group (multiple groups are possible), and each Ar may be the same or different. Each R is a methylene group. m1 and m2 are independent integers in the range of 0 to 4. n is greater than 0, The objective is to provide a phenol resin in which, when the phenol resin is characterized by gel permeation chromatography (GPC), the total area of ​​peaks representing the region where n is less than 5 is A, the total area of ​​peaks representing the region where n is 5 or more is B, and the ratio of B to A (B / A) is 0.35 to 1.32.

[0009] In one embodiment of the present invention, each Ar is independently a divalent group derived from a phenol, cresol, m-benzenediol, or bisphenol compound.

[0010] In one embodiment of the present invention, n is in the range of 1 to 400.

[0011] In one embodiment of the present invention, when the phenol resin is characterized by gel permeation chromatography, the total area B of the peaks representing the region where n is 5 or more is in the range of 27% to 58% of the total peak area.

[0012] In one embodiment of the present invention, when the phenol resin is characterized by gel permeation chromatography, the total area A of the peaks representing the region where n is less than 5 is in the range of 42% to 73% of the total peak area.

[0013] In one embodiment of the present invention, the gel permeation chromatography is performed as follows: the phenol resin is dissolved in tetrahydrofuran at a concentration of 1.25% by weight; the dissolved phenol resin is supplied to a series of columns at a flow rate of 1.0 mL / min for separation; the sample is collected and the collected sample is analyzed using a refractive index detector. Here, the series of columns consists of one column C1, two columns C2, and one column C3 in that order, with column C1 having a length of 30 cm and an inner diameter of 7.8 mm and being packed with polystyrene-divinylbenzene having an average particle size of 5 μm and an average pore size of 7.5 nm; each of the columns C2 having a length of 30 cm and an inner diameter of 7.8 mm and being packed with polystyrene-divinylbenzene having an average particle size of 5 μm and an average pore size of 2 nm; and column C3 having a length of 30 cm and an inner diameter of 7.8 mm and being packed with polystyrene-divinylbenzene having an average particle size of 5 μm and an average pore size of 1.5 nm.

[0014] In one embodiment of the present invention, a methyl ethyl ketone solution containing 70% by weight of the phenol resin has a viscosity of 900 cp to 4300 cp at 25°C.

[0015] In one embodiment of the present invention, the hydroxyl group equivalent of the phenol resin is 220 to 245 g / eq.

[0016] Another object of the present invention is to provide a thermosetting resin composition comprising the phenol resin and solvent described above.

[0017] In one embodiment of the present invention, the thermosetting resin composition further contains an additive selected from the group consisting of a curing agent, a curing accelerator, an elastomer, a filler, a dispersant, a reinforcing agent, a viscosity modifier, a flame retardant, a plasticizer, a coupling agent, and combinations thereof.

[0018] Another object of the present invention is to provide a prepreg adjusted by impregnating a substrate with the above-described thermosetting resin composition or by applying the above-described thermosetting resin composition to a substrate and drying the impregnated or applied substrate.

[0019] Another object of the present invention is to provide a metal-clad laminate prepared by laminating the above-described prepreg and a metal foil or by applying the above-described thermosetting resin composition to a metal foil and drying the applied metal foil.

[0020] To make the above objects, technical features, and advantages of the present invention more clear, the present invention will be described in detail below with reference to some specific embodiments.

Embodiments for Carrying out the Invention

[0021] Some specific embodiments of the present invention will be described in detail. However, the present invention may be implemented in various embodiments and should not be limited to the embodiments described in this specification.

[0022] Unless otherwise stated, expressions such as "a", "the", etc. described in this specification and the claims are intended to include both singular and plural forms.

[0023] In this specification and the claims, the units of weight average molecular weight (Mw) and number average molecular weight (Mn) are grams per mole (g / mol).

[0024] The advantage of this application is, compared with the prior art, in particular, by controlling the gel permeation chromatography characteristics of the phenolic resin, to improve the storage stability and processability of the phenolic resin. This is surprising because it has not been recognized in the prior art that the storage stability and processability of the phenolic resin are related to its GPC characteristics. Details of the phenolic resin of the present invention and its uses are described below.

[0025] 1. Phenolic resin 1.1. Structure of phenolic resin The phenolic resin of the present invention refers to a biphenyl-type phenolic resin, which is defined as a resin containing both a biphenyl structure and a phenolic structure in its molecular structure. The biphenyl-type phenolic resin can be prepared by reacting a biphenyl compound with a phenolic compound. In the present invention, the phenolic resin has a structure represented by the following formula (I):

[0026]

Chemical formula

[0027] Here, the definitions of Ar, R, m1, m2 and n are as follows.

[0028] [Ar] Ar is an arylene having one or more hydroxyl groups, and thus has a phenolic structure. Each Ar may be the same or different, and the H bonded to Ar is the H on the aromatic ring of Ar. Ar can be a structural unit derived from a phenolic compound. In one embodiment of the present invention, each Ar can independently be a divalent group derived from phenol, cresol, resorcinol or a bisphenol compound. Therefore, each Ar is independently

[0029]

Chemical formula

[0030] This is possible. In the formula, R1 and R2 are independently hydrogen atoms or organic groups.

[0031] [R] R is methylene (i.e., -CH2-), which may be a reaction residue resulting from the reaction between a biphenyl compound and a phenol compound.

[0032] [m1 and m2] m1 and m2 represent the number of methyl groups on the benzene ring of the biphenyl structure. Since the biphenyl structure of this resin may be derived from a biphenyl compound, m1 and m2 can independently be integers ranging from 0 to 4, depending on the type of biphenyl compound.

[0033] [n] n is greater than 0 and represents the number of repetitions of the structural unit in parentheses. n is preferably in the range of 1 to 400, more particularly in the range of 1 to 200, and even more specifically in the range of 1 to 100. The value of n can be determined by the molecular weight of the phenolic resin. In one embodiment of the present invention, n is in the range of 1 to 20, which is determined by the weight-average molecular weight Mw of the phenolic resin.

[0034] 1.2. Gel Permeation Chromatography (GPC) Properties of Phenolic Resins When characterizing phenolic resins by gel permeation chromatography, regions with different n values ​​produce distinct signals at different positions on the spectrum. Generally, the smaller the n value, the longer the elution time in gel permeation chromatography measurements. Therefore, based on the order of elution times, the peaks in the gel permeation chromatography spectrum can be sequentially identified by their corresponding n values. The inventors have found that by controlling the peak area ratio of regions representing different n values, the resulting phenolic resin represented by formula (I) exhibits excellent storage stability and processability.

[0035] In detail, when characterizing phenolic resin by gel permeation chromatography, the total area of ​​peaks representing the region where n is less than 5 is A, the total area of ​​peaks representing the region where n is 5 or greater is B, and the ratio of B to A (B / A) is 0.35 to 1.32. For example, the B / A value may be 0.35, 0.38, 0.40, 0.43, 0.45, 0.48, 0.50, 0.53, 0.55, 0.58, 0.60, 0.63, 0.65, 0.68, 0.70, 0.73, 0.75, 0.78, 0.80, 0.83, 0.85, 0.88, 0.90, 0.93, 0.95, 0.98, 1.00, 1.03, 1.05, 1.08, 1.10, 1.13, 1.15, 1.18, 1.20, 1.23, 1.25, 1.28, 1.30, or 1.32, or within the range of any two of the values ​​described herein. The inventors have found that when the B / A value is lower than the lower limit of the range described above, the storage stability of the phenolic resin represented by formula (I) is poor, and the phenolic resin tends to precipitate from the solvent. When the B / A value is higher than the upper limit of the range described above, the processability of the phenolic resin represented by formula (I) is poor, and the resulting metal-clad laminate has insufficient resin, resulting in an incomplete dielectric layer.

[0036] In the present invention, gel permeation chromatography is performed as follows: a phenolic resin is dissolved in tetrahydrofuran at a concentration of 1.25% by weight; the dissolved phenolic resin is supplied to a series of columns at a flow rate of 1.0 mL / min for separation; the sample is collected and the collected sample is analyzed using a refractive index detector. Here, the series of columns consists of one column C1, two columns C2, and one column C3 in this order, with column C1 being 30 cm long and 7.8 mm in diameter and packed with polystyrene-divinylbenzene having an average particle size of 5 μm and an average pore size of 7.5 nm; each of column C2 being 30 cm long and 7.8 mm in diameter and packed with polystyrene-divinylbenzene having an average particle size of 5 μm and an average pore size of 2 nm; and column C3 being 30 cm long and 7.8 mm in diameter and packed with polystyrene-divinylbenzene having an average particle size of 5 μm and an average pore size of 1.5 nm. In this invention, the peaks of the resulting gel permeation chromatography spectrum are sequentially identified by their corresponding n values ​​based on the order of elution times. Next, software is used to assist in calculating the peak area and corresponding ratio of the region representing each n value. Here, the peak area is calculated as the integral area defined by the line connecting the start and end points of the peaks within the specified range.

[0037] Under the condition that the B / A value is between 0.35 and 1.32, the signal distribution in the region where n is less than 5 and the region where n is 5 or greater in the gel permeation chromatography spectrum is not particularly limited. That is, the region where n is less than 5 may consist of one or more subregions where n is less than 5. The region where n is 5 or greater may consist of one or more subregions where n is 5 or greater, and more specifically, one or more subregions where n is in the range of 5 to 400. In one embodiment of the present invention, the region where n is less than 5 mainly includes the subregions n=1, n=2, n=3, and n=4; and the region where n is 5 or greater mainly includes the subregions n=5, n=6, and n=7.

[0038] In one embodiment of the present invention, when a phenolic resin is characterized by gel permeation chromatography, the total area B of peaks representing the region where n is 5 or greater is in the range of 27% to 58% of the total peak area. For example, the total area B of peaks representing the region where n is 5 or greater, relative to the total peak area, may be 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, or 58%, or within the range of any two of the values ​​described herein.

[0039] In one embodiment of the present invention, when a phenolic resin is characterized by gel permeation chromatography, the total area A of peaks representing the region where n is less than 5 is in the range of 42% to 73% of the total peak area. For example, the total area A of peaks representing the region where n is less than 5 relative to the total peak area may be 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, or 73%, or within the range of any two of the values ​​described herein.

[0040] In one embodiment of the present invention, when a phenolic resin is characterized by gel permeation chromatography, the peak representing the region where n is 1 has an area a1, and area a1 is 20% or more of the total peak area, and more particularly in the range of 20% to 30% of the total peak area. For example, with respect to the total peak area, area a1 may be 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30%, or within the range of any two of the values ​​described herein.

[0041] The GPC properties of the phenolic resin of the present invention can be adjusted by controlling the composition of the raw materials or the reaction conditions. For example, one way to control the composition of the raw materials is to adjust the B / A value by controlling the molar ratio of the phenolic compound to the biphenyl compound in the raw materials. Generally, the higher the molar ratio of the phenolic compound to the biphenyl compound (moles of phenolic compound / moles of biphenyl compound), the lower the B / A value, and conversely, the lower the molar ratio, the higher the B / A value. One way to control the reaction conditions is to control the reaction temperature or to prepare the resin using a stepwise polymerization process. Generally, the higher the reaction temperature, the higher the B / A value, and conversely, the lower the reaction temperature, the lower the B / A value.

[0042] 1.3. Other properties of phenolic resins Under conditions where the B / A value is between 0.35 and 1.32, other properties of the phenolic resin of the present invention can be adaptively adjusted according to the requirements of the intended application.

[0043] In one embodiment of the present invention, the phenolic resin has a weight-average molecular weight Mw of 1600 or more, preferably between 1600 and 4300. For example, the weight-average molecular weight Mw of the phenolic resin may be 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, or 4300, or within the range of any two of the values ​​described herein. The unit of weight-average molecular weight Mw is g / mol. The weight-average molecular weight Mw is measured by the gel permeation chromatography described above.

[0044] The phenolic resin may have a number-average molecular weight Mn in the range of 800 to 2000, preferably 950 to 1600. For example, the number-average molecular weight Mn of the phenolic resin may be 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500, 1550, or 1600, or within the range of any two of the values ​​described herein.

[0045] Phenolic resins can have a polydispersity index PDI (i.e., "Mw / Mn") in the range of 1.1 to 3.5, preferably 1.3 to 3.2. For example, the polydispersity index PDI of a phenolic resin may be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, or 3.2, or within the range of any two of the values ​​described herein.

[0046] In one embodiment of the present invention, a methyl ethyl ketone solution of a phenol resin with a solid content of 70% by weight has a viscosity of 900 cp to 4300 cp at 25°C. For example, the viscosity of a methyl ethyl ketone solution of a phenol resin with a solid content of 70% by weight at 25°C may be 900 cp, 1000 cp, 1200 cp, 1400 cp, 1600 cp, 1800 cp, 2000 cp, 2200 cp, 2400 cp, 2600 cp, 2800 cp, 3000 cp, 3200 cp, 3400 cp, 3600 cp, 3800 cp, 4000 cp, 4200 cp, or 4300 cp, or within the range of any two of the values ​​described herein.

[0047] In an embodiment of the present invention, the hydroxyl equivalent number of the phenol resin is 220 to 245 g / eq. For example, the hydroxyl equivalent number of the phenol resin may be 220 g / eq, 221 g / eq, 222 g / eq, 223 g / eq, 224 g / eq, 225 g / eq, 226 g / eq, 227 g / eq, 228 g / eq, 229 g / eq, 230 g / eq, 231 g / eq, 232 g / eq, 233 g / eq, 234 g / eq, 235 g / eq, 236 g / eq, 237 g / eq, 238 g / eq, 239 g / eq, 240 g / eq, 241 g / eq, 242 g / eq, 243 g / eq, 244 g / eq, or 245 g / eq, or within the range of any two of the values ​​described herein. The hydroxyl group equivalent number is measured in accordance with JIS K 0070.

[0048] 2. Preparation of phenolic resin The method for preparing the phenolic resin of the present invention is not particularly limited. For example, the phenolic resin can be prepared by uniformly mixing raw materials containing biphenyl compounds and phenolic compounds and reacting this mixture for a suitable time and at a suitable temperature. Detailed preparation methods are illustrated in the following examples and will not be explained in further detail here.

[0049] 3.Resin composition The phenolic resin of the present invention has excellent storage stability and can be uniformly mixed with a solvent and optionally additives, and dissolved or dispersed in the solvent to form a slurry, colloid group, varnish, or other form. Accordingly, the present invention also provides a thermosetting resin composition comprising the above-described phenolic resin and solvent.

[0050] The solvent can be an inert solvent that can dissolve or disperse the components of the resin composition but does not react with those components, and this includes aromatic hydrocarbons, ethers, alcohols, or ketones. Examples of solvents include, but are not limited to, acetone, buttanone, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, propylene glycol methyl ether, γ-butyrolactone, dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP). The solvents mentioned above can be used alone or in any combination. There is no particular limit to the amount of solvent used, as long as it is possible to uniformly dissolve or disperse the components of the resin composition.

[0051] Without departing from the technical principles of the present invention, the resin composition of the present invention may further contain any components as needed to adaptively improve the processability of the resin composition during the manufacturing process or to enhance the physicochemical properties of electronic materials made from the resin composition. Examples of optional components include, but are not limited to, additives selected from the group consisting of curing agents, curing accelerators, elastomers, fillers, dispersants, reinforcing agents, viscosity modifiers, flame retardants, plasticizers, and coupling agents. The above-mentioned additives can be used individually or in any combination.

[0052] 4. Prepregs and metal-clad laminates The present invention also provides a prepreg prepared from the thermosetting resin composition described above. The prepreg is prepared by impregnating a substrate with the thermosetting resin composition described above, or by coating a substrate with the thermosetting resin composition described above, and then drying the impregnated or coated substrate. The substrate can be used as a reinforcing material. Examples of reinforcing materials typically include, but are not limited to, fibers selected from the group consisting of glass fibers, inorganic fibers other than glass fibers, organic fibers, and combinations thereof. Examples of glass fibers include, but are not limited to, E glass fibers, NE glass fibers, S glass fibers, L glass fibers, D glass fibers, T glass fibers, Q glass fibers, UN glass fibers, spherical glass, etc. Examples of inorganic fibers other than glass fibers include, but are not limited to, quartz fibers, paper fibers, and carbon fibers. Examples of organic fibers include, but are not limited to, polyimide, polyamide (Kevlar®, etc.), polyester, liquid crystal polymer (liquid crystal polyester, etc.), polytetrafluoroethylene, ultra-high molecular weight polyethylene (UHMWPE), and high elastic polypropylene (HMPP). Reinforcement materials include, but are not limited to, woven fabrics, nonwoven fabrics, rovings, chopped strand felt, and surface felt.

[0053] Furthermore, the present invention also provides a metal-clad laminate prepared from the prepregs described above. This metal-clad laminate comprises a dielectric layer and a metal layer on at least one surface of the dielectric layer, where the dielectric layer is formed from the prepregs and the metal layer is formed from metal foil. Specifically, the metal-clad laminate can be obtained by stacking a plurality of the prepregs described above, stacking metal foil (such as copper foil) on at least one outer surface of the dielectric layer formed from the prepregs to form a laminate, and then hot-pressing this laminate to obtain a metal-clad laminate. Alternatively, the metal-clad laminate can be prepared by directly applying the thermosetting resin composition described above to metal foil and drying the applied metal foil.

[0054] The outer metal foil of the metal-clad laminate can be further patterned to form a printed circuit board.

[0055] 5. Examples 5.1. Test Method This application will be further described by the following embodiments. The test apparatus and method are as follows:

[0056] [Gel Permeation Chromatography (GPC) Test] The prepared phenolic resin is dissolved in tetrahydrofuran at a concentration of 1.25% by weight, and then separated by feeding it at a flow rate of 1.0 mL / min into a series of columns consisting of one column C1 (model: Tosoh TSKgel G3000HxL), two columns C2 (model: Tosoh TSKgel G2000HxL), and one column C3 (model: Tosoh TSKgel G1000HxL). Column C1 is 30 cm long and 7.8 mm in inner diameter, and is packed with polystyrene-divinylbenzene with an average particle size of 5 μm and an average pore size of 7.5 nm. Each of the columns C2 is 30 cm long and 7.8 mm in inner diameter, and is packed with polystyrene-divinylbenzene with an average particle size of 5 μm and an average pore size of 2 nm. Column C3 is 30 cm long and 7.8 mm in diameter, packed with polystyrene-divinylbenzene with an average particle size of 5 μm and an average pore size of 1.5 nm. The sample is collected and analyzed using a refractive index detector (Waters 2414 R1 detector). The peaks of the resulting gel permeation chromatography spectrum are sequentially identified by their corresponding n values ​​based on the order of elution times. Next, the peak area and corresponding ratio of the region representing each n value are calculated using SISC32 software available from Scientific Information Service Company. Here, the peak area is calculated as the integral area defined by the line connecting the start and end points of the peaks within the specified range.

[0057] [Viscosity measurement] The prepared phenolic resin is mixed with a methyl ethyl ketone solution at a solid content of 70% by weight and left in a constant temperature bath at 25°C for 2 hours. Next, the viscosity is measured using a Brookfield viscometer, with the unit of viscosity being centipoise (cp).

[0058] [Hydroxygroup equivalent number measurement] The hydroxyl group equivalents of the prepared phenolic resin are measured in accordance with JIS K 0070. The unit of hydroxyl group equivalents is g / eq.

[0059] [Storage stability test] The prepared phenolic resin is mixed with a methyl ethyl ketone solution at a solid content of 70% by weight and left in a refrigerator at 5°C. The solution is observed daily to check for the presence of precipitate. The presence of precipitate is recorded. If no precipitate is observed after 70 days, it is recorded as "no precipitate".

[0060] [Processability test] Prepare a varnish by mixing the prepared phenolic resin with epoxy resin (CNE200, available from Chang Chun Plastics Company) in a 1:1 ratio (epoxy equivalents to hydroxyl group equivalents), and control the gelation time to 100 to 120 seconds. Impregnate a fiberglass cloth with this varnish and dry it to prepare a prepreg. Five layers of this prepreg are stacked, copper foil is placed on each of the outermost layers on both sides, and then the assembly is hot-pressed. After hot-pressing, the copper foil is removed by etching, and the surface of the fiberglass cloth is checked for any resin deficiency. If resin deficiency is observed, it means the processability test has failed, and the result is recorded as "×". If no resin deficiency is observed, it means the processability test has passed, and the result is recorded as "〇".

[0061] 5.2. Preparation of phenolic resin [Example 1] 275.3 g of phenol and 1 g of p-toluenesulfonic acid were added to a four-necked flask equipped with a stirrer, thermometer, and condenser. While stirring at 80°C, 306.1 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl was added, and the reaction was maintained at 80°C for 2 hours to obtain the reaction product.

[0062] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, and then the mixture was washed with water. After washing, the resulting oil layer was subjected to heating under reduced pressure to remove unreacted phenol, yielding 386 g of phenolic resin. The weight-average molecular weight Mw of the prepared phenolic resin was 1625, the number-average molecular weight Mn was 986, and the polydispersity index PDI was 1.648.

[0063] [Example 2] In a four-necked flask equipped with a stirrer, thermometer, and condenser, 29.8 g of phenol and 1 g of p-toluenesulfonic acid were added. While stirring at 90°C, 42.2 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl was added, and the reaction was maintained at 90°C for 2 hours. Subsequently, 94.1 g of phenol and 84.5 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl were further added, and the reaction was maintained at 90°C for 2 hours to obtain the reaction product.

[0064] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, and then the mixture was washed with water. After washing, the resulting oil layer was subjected to heating under reduced pressure to remove unreacted phenol, yielding 152 g of phenol resin. The weight-average molecular weight Mw of the prepared phenol resin was 3017, the number-average molecular weight Mn was 1048, and the polydispersity index PDI was 2.879.

[0065] [Example 3] 275.3 g of phenol and 1 g of p-toluenesulfonic acid were added to a four-necked flask equipped with a stirrer, thermometer, and condenser. While stirring at 80°C, 329.5 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl was added, and the reaction was maintained at 80°C for 2 hours to obtain the reaction product.

[0066] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, and then the mixture was washed with water. After washing, the resulting oil layer was subjected to heating under reduced pressure to remove unreacted phenol, yielding 412 g of phenolic resin. The weight-average molecular weight Mw of the prepared phenolic resin was 1758, the number-average molecular weight Mn was 1008, and the polydispersity index PDI was 1.744.

[0067] [Example 4] 89.2 g of phenol and 1 g of p-toluenesulfonic acid were added to a four-necked flask equipped with a stirrer, thermometer, and condenser. While stirring at 100°C, 140.0 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl was added, and the reaction was maintained at 100°C for 2 hours. Subsequently, 336.0 g of phenol and 280.0 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl were further added, and the reaction was maintained at 100°C for 2 hours to obtain the reaction product.

[0068] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, and then the mixture was washed with water. After washing, the resulting oil layer was subjected to heating under reduced pressure to remove unreacted phenol, yielding 508 g of phenolic resin. The weight-average molecular weight Mw of the prepared phenolic resin was 2318, the number-average molecular weight Mn was 967, and the polydispersity index PDI was 2.397.

[0069] [Example 5] 70.1 g of phenol and 1 g of p-toluenesulfonic acid were added to a four-necked flask equipped with a stirrer, thermometer, and condenser. While stirring at 100°C, 110.0 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl was added, and the reaction was maintained at 100°C for 2 hours. Subsequently, 247.3 g of phenol and 220.0 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl were further added, and the reaction was maintained at 100°C for 2 hours to obtain the reaction product.

[0070] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, and then the mixture was washed with water. After washing, the resulting oil layer was subjected to heating under reduced pressure to remove unreacted phenol, yielding 396 g of phenol resin. The weight-average molecular weight Mw of the prepared phenol resin was 3373, the number-average molecular weight Mn was 1069, and the polydispersity index PDI was 3.155.

[0071] [Example 6] In a four-necked flask equipped with a stirrer, thermometer, and condenser, 129.2 g of phenol and 1 g of p-toluenesulfonic acid were added. While stirring at 100°C, 202.8 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl was added, and the reaction was maintained at 100°C for 2 hours to obtain the reaction product.

[0072] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, and then the mixture was washed with water. After washing, the resulting oil layer was subjected to heating under reduced pressure to remove unreacted phenol, yielding 241 g of phenol resin. The weight-average molecular weight Mw of the prepared phenol resin was 3906, the number-average molecular weight Mn was 1585, and the polydispersity index PDI was 2.464.

[0073] [Comparative Example 1] 526.1 g of phenol and 1 g of p-toluenesulfonic acid were added to a four-necked flask equipped with a stirrer, thermometer, and condenser. While stirring at 70°C, 329.5 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl was added, and the reaction was maintained at 70°C for 2 hours to obtain the reaction product.

[0074] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, and then the mixture was washed with water. After washing, the resulting oil layer was subjected to heating under reduced pressure to remove unreacted phenol, yielding 432 g of phenolic resin. The weight-average molecular weight Mw of the prepared phenolic resin was 902, the number-average molecular weight Mn was 661, and the polydispersity index PDI was 1.365.

[0075] [Comparative Example 2] 182.7 g of phenol and 1 g of p-toluenesulfonic acid were added to a four-necked flask equipped with a stirrer, thermometer, and condenser. While stirring at 70°C, 130.0 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl was added, and the reaction was maintained at 70°C for 2 hours to obtain the reaction product.

[0076] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, and then the mixture was washed with water. After washing, the resulting oil layer was subjected to heating under reduced pressure to remove unreacted phenol, yielding 169 g of phenolic resin. The weight-average molecular weight Mw of the prepared phenolic resin was 1102, the number-average molecular weight Mn was 746, and the polydispersity index PDI was 1.477.

[0077] [Comparative Example 3] In a four-necked flask equipped with a stirrer, thermometer, and condenser, 129.2 g of phenol and 1 g of p-toluenesulfonic acid were added. While stirring at 100°C, 215.4 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl was added, and the reaction was maintained at 100°C for 2 hours to obtain the reaction product.

[0078] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, and then the mixture was washed with water. After washing, the resulting oil layer was subjected to heating under reduced pressure to remove unreacted phenol, yielding 254 g of phenol resin. The weight-average molecular weight Mw of the prepared phenol resin was 4340, the number-average molecular weight Mn was 1738, and the polydispersity index PDI was 2.497.

[0079] [Comparative Example 4] In a four-necked flask equipped with a stirrer, thermometer, and condenser, 70.1 g of phenol and 1 g of p-toluenesulfonic acid were added. While stirring at 60°C, 110.0 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl was added, and the reaction was maintained at 60°C for 2 hours. Subsequently, 247.3 g of phenol and 220.0 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl were further added, and the reaction was maintained at 60°C for another 2 hours.

[0080] The experimental results indicate that in this comparative example, phenol does not react completely with 4,4'-bis(chloromethyl)-1,1'-biphenyl, and therefore no phenolic resin is obtained.

[0081] [Comparative Example 5] In a four-necked flask equipped with a stirrer, thermometer, and condenser, 129.2 g of phenol and 1 g of p-toluenesulfonic acid were added. While stirring at 110°C, 202.8 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl was added, and the reaction was maintained at 110°C for 2 hours to obtain the reaction product.

[0082] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, and then the mixture was washed with water. After washing, the resulting oil layer was subjected to heating under reduced pressure to remove unreacted phenol, yielding 239 g of phenol resin. The weight-average molecular weight Mw of the prepared phenol resin was 4102, the number-average molecular weight Mn was 1620, and the polydispersity index PDI was 2.532.

[0083] [Comparative Example 6] 129.2 g of phenol and 1 g of p-toluenesulfonic acid were added to a four-necked flask equipped with a stirrer, thermometer, and condenser. 208.9 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl was added while stirring at 70°C, and the reaction was maintained at 70°C for 2 hours to obtain the reaction product.

[0084] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, and then the mixture was washed with water. After washing, the resulting oil layer was subjected to heating under reduced pressure to remove unreacted phenol, yielding 246 g of phenolic resin. The weight-average molecular weight Mw of the prepared phenolic resin was 3845, the number-average molecular weight Mn was 1643, and the polydispersity index PDI was 2.340.

[0085] 5.3. Characterization of Phenolic Resins The properties of the phenolic resins in Examples 1-6 and Comparative Examples 1-6, including gel permeation chromatography characteristics, viscosity, hydroxyl group equivalent number, storage stability, and processability, were measured according to the test methods described above. The results are recorded in Tables 1-1 and 1-2.

[0086] [Table 1]

[0087] [Table 2]

[0088] As shown in Tables 1-1 and 1-2, the phenolic resins of Examples 1-6 of the present invention exhibit good storage stability, with a precipitation time of 21 days or more, and no resin deficiency was observed, demonstrating good processability. In contrast, the phenolic resins of Comparative Examples 1-6 do not simultaneously possess these excellent properties. Comparative Examples 1 and 2 show that when the B / A value is lower than the range specified in the present invention, the phenolic resin precipitates from the solvent in a very short time, indicating poor storage stability. Comparative Examples 3 and 5-6 show that when the B / A value is higher than the range specified in the present invention, the phenolic resin becomes resin-deficient, making it impossible to form the desired shape, indicating poor processability.

[0089] The above examples illustrate the principles and effectiveness of this application and demonstrate its inventive features. Those skilled in the art may make various modifications and substitutions based on the disclosures and suggestions of this application without departing from the principles. Accordingly, the scope of protection of this application is as defined in the appended claims.

Claims

1. A phenolic resin represented by the following formula (I), 【Chemistry 1】 During the ceremony, Each Ar is a divalent group derived from phenol or cresol, and each Ar may be the same or different. Each R is a methylene group. m1 and m2 are independent integers in the range of 0 to 4. n is greater than 0, When the phenolic resin is characterized by gel permeation chromatography (GPC), the total area of ​​peaks representing the region where n is less than 5 is A, the total area of ​​peaks representing the region where n is 5 or greater is B, and the ratio of B to A (B / A) is 0.35 to 1.

32. The gel permeation chromatography is performed as follows: the phenol resin is dissolved in tetrahydrofuran at a concentration of 1.25% by weight; the dissolved phenol resin is supplied to a series of columns at a flow rate of 1.0 mL / min for separation; the sample is collected, and the collected sample is analyzed using a refractive index detector. The aforementioned series of columns consists of one column C1, two columns C2, and one column C3, arranged in this order. Column C1 is 30 cm long and has an inner diameter of 7.8 mm, and is packed with polystyrene-divinylbenzene with an average particle size of 5 μm and an average pore size of 7.5 nm. Each of the columns C2 is 30 cm long and has an inner diameter of 7.8 mm, and is packed with polystyrene-divinylbenzene with an average particle size of 5 μm and an average pore size of 2 nm. Each of the columns C3 is 30 cm long and has an inner diameter of 7.8 mm, and is packed with polystyrene-divinylbenzene with an average particle size of 5 μm and an average pore size of 1.5 nm. The phenolic resin has a number average molecular weight Mn in the range of 800 to 2000. The phenolic resin is a phenolic resin having a polydispersity index PDI in the range of 1.1 to 3.

5.

2. The phenolic resin according to claim 1, wherein n is in the range of 1 to 400.

3. The phenol resin according to claim 1, wherein when the phenol resin is characterized by gel permeation chromatography, the total area B of the peaks representing the region where n is 5 or more is in the range of 27% to 56% of the total peak area.

4. The phenol resin according to any one of claims 1 to 3, wherein a methyl ethyl ketone solution containing 70% by weight of the phenol resin has a viscosity of 900 cp to 4300 cp at 25°C.

5. The phenol resin according to any one of claims 1 to 3, wherein the hydroxyl group equivalent of the phenol resin is 220 to 245 g / eq.

6. A thermosetting resin composition comprising a phenol resin according to any one of claims 1 to 3 and a solvent.

7. The thermosetting resin composition according to claim 6, further comprising an additive selected from the group consisting of a curing agent, a curing accelerator, an elastomer, a filler, a dispersant, a reinforcing agent, a viscosity modifier, a flame retardant, a plasticizer, a coupling agent, and combinations thereof.

8. A prepreg prepared by impregnating a substrate with the thermosetting resin composition described in claim 6, or coating a substrate with it, and drying the impregnated or coated substrate.

9. A metal-clad laminate prepared by laminating the prepreg described in claim 8 with a metal foil.

10. A metal-clad laminate prepared by applying the thermosetting resin composition described in claim 6 to a metal foil and drying the coated metal foil.

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