Phenol resin and application thereof

Abstract

The present invention provides a phenolic resin represented by formula (I) (wherein Ar represents an aryl group having a hydroxyl group, and each Ar may be the same or different; r is a methyl group; m1 and m2 are each independently an integer from 0 to 4; n is greater than 0; and when the phenolic resin is measured by gel permeation chromatography (GPC), the total peak area of a portion where n is less than 5 is A, the total peak area of a portion where n is 5 or more is B, and the ratio of B to A (B / A) is 0.35 to 1.32.

Description

Technical Field

[0001] This invention relates to a phenolic resin, and more particularly to a phenolic resin possessing specific gel permeation chromatography (GPC) properties. The phenolic resin of this invention exhibits good solvent solubility, preservation, and processability, making it particularly suitable for use in metal foil laminates. Background Technology

[0002] Printed circuit boards (PCBs) serve as substrates for electronic devices, housing various electrically interconnected electronic components to provide a stable circuit operating environment. A common PCB substrate is the copper clad laminate (CCL).

[0003] Generally, copper foil laminates can be manufactured as follows: A thermosetting resin (e.g., phenolic resin, epoxy resin, etc.) is uniformly mixed with other additives and dissolved or dispersed in a solvent to form a varnish. A reinforcing material (e.g., fiberglass fabric) is impregnated with this varnish, and the impregnated reinforcing material is cured to a semi-cured state (i.e., B-stage) to obtain a precured sheet. Subsequently, a predetermined number of precured sheets are stacked, and a copper foil is stacked on at least one outer side of the stacked precured sheets to provide a laminate. The laminate is then subjected to a hot-pressing operation (i.e., C-stage) to obtain a copper foil laminate.

[0004] Examples of thermosetting resins include phenolic resins and epoxy resins, among which phenolic resins are widely used due to their excellent insulation and heat resistance. However, to ensure the quality stability of copper foil laminates, the varnishes formulated with thermosetting resins must have good shelf life, meaning that they should not crystallize or separate during long-term storage. Existing phenolic resins generally suffer from the problem of easy crystallization and poor solvent solubility and shelf life. Summary of the Invention

[0005] In view of this, the present invention provides a phenolic resin that not only has good solvent solubility and preservation properties, but also exhibits good processability in the application of dielectric layer materials for the manufacture of metal foil laminates, and the resulting metal foil laminates will not have adhesive shortage.

[0006] Therefore, one object of the present invention is to provide a phenolic resin, which is shown in the following formula (I).

[0007]

[0008] in,

[0009] Ar is an aryl group with a hydroxyl group, and each Ar may be the same or different;

[0010] R is an elongyl group;

[0011] m1 and m2 are each independent integers from 0 to 4;

[0012] n is greater than 0; and

[0013] When the phenolic resin is measured by gel permeation chromatography, the sum of the peak areas of the portion where n is less than 5 is called A, and the sum of the peak areas of the portion where n is greater than 5 is called B, and the ratio of B to A (B / A) is 0.35 to 1.32.

[0014] In one embodiment of the present invention, each Ar is independently a divalent group derived from phenol, cresol, resorcinol, or bisphenol compounds.

[0015] In one embodiment of the present invention, n is 1 to 400.

[0016] In one embodiment of the present invention, when the phenolic resin is measured by gel permeation chromatography, the sum of the peak areas B of the portions where n is 5 or more accounts for 27% to 58% of the total area.

[0017] In one embodiment of the present invention, when the phenolic resin is measured by gel permeation chromatography, the sum of the peak areas A of the portions where n is less than 5 accounts for 42% to 73% of the total area.

[0018] In one embodiment of the present invention, gel permeation chromatography is performed under the following test conditions: phenolic resin is dissolved in tetrahydrofuran at a concentration of 1.25% by weight; separation is performed by sequentially connecting a column C1, two columns C2, and a column C3 at a flow rate of 1.0 mL / min, wherein column C1 is 30 cm long, has an inner diameter of 7.8 mm, and is filled 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, has an inner diameter of 7.8 mm, and is filled with polystyrene-divinylbenzene with an average particle size of 5 μm and an average pore size of 2 nm; and column C3 is 30 cm long, has an inner diameter of 7.8 mm, and is filled 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.

[0019] In one embodiment of the present invention, a 70% by weight solids solution of phenolic resin in methyl ethyl ketone has a viscosity of 900 centipoise (cp) to 4300 centipoise at 25°C.

[0020] In one embodiment of the present invention, the hydroxyl equivalent of the phenolic resin is 220 to 245 g / eq.

[0021] Another object of the present invention is to provide a thermosetting resin composition comprising the above-mentioned phenolic resin and solvent.

[0022] In one embodiment of the invention, the thermosetting resin composition further comprises additives selected from the group consisting of: hardeners, hardening accelerators, elastomers, fillers, dispersants, toughening agents, viscosity modifiers, flame retardants, plasticizers, coupling agents, and combinations thereof.

[0023] Another object of the present invention is to provide a semi-cured sheet, which is obtained by impregnating or coating a substrate with the above-mentioned thermosetting resin composition and drying the impregnated or coated substrate.

[0024] Another object of the present invention is to provide a metal foil laminate, which is obtained by laminating the above-mentioned prepreg with a metal foil, or by coating the above-mentioned thermosetting resin composition onto a metal foil and drying the coated metal foil.

[0025] To make the above-mentioned objectives, technical features and advantages of the present invention more apparent and understandable, the following detailed description is provided with reference to some specific embodiments. Detailed Implementation

[0026] The following describes some specific embodiments of the present invention; however, the present invention can be practiced in many different forms and should not be construed as limited to those set forth in the specification.

[0027] Unless otherwise stated, the terms “a,” “the,” and similar terms used in this specification and claims shall be understood to include both singular and plural forms.

[0028] In this article, the units for weight average molecular weight Mw and number average molecular weight Mn are grams per mole (g / mol).

[0029] The advantages of this invention compared to the prior art lie particularly in that, by controlling the gel permeation chromatography properties of phenolic resins, it improves their solvent solubility, preservation, and processability. These advantages are surprising because the correlation between the solvent solubility, preservation, and processability of phenolic resins and their GPC properties has never been recognized in the prior art. The following provides a detailed description of the phenolic resins of this invention and their applications.

[0030] 1. Phenolic resin

[0031] 1.1. Structure of phenolic resins

[0032] The phenolic resin of this invention refers to a biphenyl-type phenolic resin. A biphenyl-type phenolic resin is a resin that simultaneously possesses both a biphenyl structure and a phenolic structure in its molecule, and can be prepared by reacting a biphenyl compound with a phenolic compound. In this invention, the phenolic resin has the structure shown in formula (I):

[0033]

[0034] The definitions of Ar, R, m1, m2, and n are as follows.

[0035] [Ar]

[0036] Ar is an aryl group with a hydroxyl group, and therefore has a phenolic structure, and each Ar can be the same or different. Ar can be a structural unit derived from phenolic compounds. In one embodiment of the invention, each Ar can be an independent divalent group derived from phenol, cresol, resorcinol, or bisphenol compounds. Therefore, each Ar can be an independent divalent group derived from phenol, cresol, resorcinol, or bisphenol compounds. R1 and R2 are each an independent hydrogen atom or an organic group.

[0037] [R]

[0038] R stands for promethyl group, i.e., -CH2-, which can be a reaction residue of biphenyl compounds and phenolic compounds.

[0039] [m1 and m2]

[0040] m1 and m2 represent the number of methyl groups on the benzene ring of the biphenyl structure. Since the biphenyl structure of the resin can be derived from biphenyl compounds, m1 and m2 can each be independent integers from 0 to 4, depending on the type of biphenyl compound.

[0041] [n]

[0042] n is greater than 0, which represents the number of repetitions of the structural unit in parentheses, preferably 1 to 400, more specifically 1 to 200, and even more specifically 1 to 100. n can be determined by the molecular weight of the phenolic resin. In one embodiment of the invention, n is 1 to 20, and the value of n is determined by the weight average molecular weight Mw.

[0043] 1.2. Properties of Phenolic Resin by Gel Permeation Chromatography (GPC)

[0044] When the phenolic resin of this invention is measured by gel permeation chromatography, portions with different n values ​​will produce different signals at different positions in the chromatogram. Generally, the smaller the n value, the longer the elution time in the gel permeation chromatography measurement. Therefore, the peak values ​​in the gel permeation chromatography chromatogram can be sequentially labeled with their corresponding n values ​​according to the order of elution time. The inventors have discovered that by controlling the peak area ratio of portions representing different n values, the obtained phenolic resin with the structure of formula (I) can have good solvent solubility, preservation, and processability.

[0045] Specifically, when the phenolic resin of the present invention is measured by gel permeation chromatography, the sum of the peak areas representing the portion where n is less than 5 is A, the sum of the peak areas representing the portion where n is 5 or more is B, and the ratio of B to A (B / A) is 0.35 to 1.32. For example, B / A can 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 a range consisting of any two of the above values. Studies have found that if the B / A value is below the lower limit of the aforementioned range, the solvent solubility and preservation of phenolic resins with the structure of formula (I) are poor, and they are prone to precipitation from the solvent. If the B / A value is above the upper limit of the aforementioned range, the processability of phenolic resins with the structure of formula (I) is poor, and the resulting metal foil laminate will have insufficient adhesive, failing to form a complete dielectric layer.

[0046] In this invention, gel permeation chromatography is performed under the following test conditions: phenolic resin is dissolved in tetrahydrofuran at a concentration of 1.25% by weight; separation is performed by sequentially connecting a column C1, two columns C2, and a column C3 at a flow rate of 1.0 mL / min. Column C1 is 30 cm long, has an inner diameter of 7.8 mm, and is filled with polystyrene-divinylbenzene with an average particle size of 5 μm and an average pore size of 7.5 nm. Column C2 is 30 cm long, has an inner diameter of 7.8 mm, and is filled 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, has an inner diameter of 7.8 mm, and is filled with polystyrene-divinylbenzene with an average particle size of 5 μm and an average pore size of 1.5 nm. Samples are collected and analyzed using a refractive index detector. In this invention, the peak values ​​in the obtained gel permeation chromatography chromatogram are sequentially labeled with their corresponding n values ​​according to the elution time. Then, software is used to calculate the peak area and related proportions of the portion representing each n value, wherein the peak area is calculated as the integral area of ​​the line connecting the start and end points of the peak within a specified range.

[0047] Under the condition that the B / A value is between 0.35 and 1.32, there are no particular restrictions on the signal distribution of the portion representing n less than 5 and the portion representing n greater than 5 in the gel permeation chromatography spectrum. In other words, the portion representing n less than 5 can be composed of one or more sub-parts with n less than 5. The portion representing n greater than 5 can be composed of one or more sub-parts with n greater than 5, more specifically, it can be composed of one or more sub-parts with n from 5 to 400. In one embodiment of the present invention, the portion representing n less than 5 mainly includes the sub-parts of n=1, n=2, n=3, and n=4, and the portion representing n greater than 5 mainly includes the sub-parts of n=5, n=6, and n=7.

[0048] In one embodiment of the present invention, when the phenolic resin is measured by gel permeation chromatography, the sum of the peak areas B representing the portion where n is 5 or more accounts for 27% to 58% of the total area. For example, the sum of the peak areas B representing the portion where n is 5 or more may account for 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% of the total area, or be within a range consisting of any two of the above values.

[0049] In one embodiment of the present invention, when the phenolic resin is measured by gel permeation chromatography, the sum of the peak areas A representing the portion where n is less than 5 accounts for 42% to 73% of the total area. For example, the sum of the peak areas A representing the portion where n is less than 5 may account for 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% of the total area, or be within a range consisting of any two of the above values.

[0050] In one embodiment of the present invention, when the phenolic resin is measured by gel permeation chromatography, the portion representing n=1 has a peak area a1, and the peak area a1 accounts for more than 20% of the total area, more specifically, 20% to 30% of the total area. For example, the peak area a1 representing the portion representing n=1 may account for 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30% of the total area, or be within a range consisting of any two of the above values.

[0051] The gel permeation chromatography properties of the phenolic resin of the present invention can be adjusted by controlling the raw material composition or reaction conditions. For example, the aforementioned means of controlling the raw material composition include controlling the molar ratio of phenolic compounds to biphenyl compounds in the raw materials to adjust the B / A value. Generally speaking, the higher the molar ratio of phenolic compounds to biphenyl compounds (moles of phenolic compounds / moles of biphenyl compounds), the lower the B / A value, and vice versa. The aforementioned means of controlling the reaction conditions include controlling the reaction temperature or using a segmented polymerization reaction to prepare the resin. Generally speaking, the higher the reaction temperature, the higher the B / A value, and vice versa.

[0052] 1.3. Other properties of phenolic resins

[0053] Other properties of the phenolic resin of the present invention can be adapted to the desired application, provided that the B / A ratio is between 0.35 and 1.32.

[0054] In one embodiment of the present invention, the weight-average molecular weight (Mw) of the phenolic resin is 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 fall within a range consisting of any two of the above values. The unit of weight-average molecular weight (Mw) is grams per mole. The weight-average molecular weight (Mw) is measured by the aforementioned gel permeation chromatography.

[0055] The number average molecular weight Mn of the phenolic resin can be from 800 to 2000, preferably from 950 to 1600. For example, the number average molecular weight Mn of the phenolic resin can be 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500, 1550, or 1600, or fall within the range of any two of the above values.

[0056] The polydispersity index (PDI) of the phenolic resin (i.e., "Mw / Mn") can be from 1.1 to 3.5, preferably from 1.3 to 3.2. For example, the polydispersity index (PDI) of the phenolic resin can 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 a range consisting of any two of the above values.

[0057] In one embodiment of the present invention, a 70% by weight solids methyl ethyl ketone solution of phenolic resin has a viscosity of 900 centipoise to 4300 centipoise at 25°C. For example, the viscosity of a 70% by weight solids methyl ethyl ketone solution of phenolic resin at 25°C may be 900 centipoise, 1000 centipoise, 1200 centipoise, 1400 centipoise, 1600 centipoise, 1800 centipoise, 2000 centipoise, 2200 centipoise, 2400 centipoise, 2600 centipoise, 2800 centipoise, 3000 centipoise, 3200 centipoise, 3400 centipoise, 3600 centipoise, 3800 centipoise, 4000 centipoise, 4200 centipoise, or 4300 centipoise, or a range consisting of any two of the above values.

[0058] In one embodiment of the present invention, the phenolic resin may have a hydroxyl equivalent of 220 to 245 g / eq. For example, the hydroxyl equivalent of the phenolic 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 a range consisting of any two of the above values. The hydroxyl equivalent was measured according to JIS K 0070.

[0059] 2. Preparation of phenolic resin

[0060] The preparation method of the phenolic resin of the present invention is not particularly limited. For example, the phenolic resin can be prepared by uniformly mixing the raw material components of the phenolic resin, including biphenyl compounds and phenolic compounds, at an appropriate temperature and continuously reacting for an appropriate time. Detailed preparation methods are illustrated in the examples below and will not be repeated here.

[0061] 3. Resin composition

[0062] The phenolic resin of this invention possesses excellent solvent solubility and preservation properties, thus it can be uniformly mixed with solvents and, if desired, additives, and dissolved or dispersed in solvents to form slurries, colloidal groups, varnishes, etc. Therefore, this invention also provides a thermosetting resin composition comprising the above-mentioned phenolic resin and a solvent.

[0063] The solvent can be any inert solvent that can dissolve or disperse the components of the resin composition but does not react with them, such as aromatic hydrocarbons, ethers, alcohols, or ketones. Examples of such solvents include, but are not limited to: acetone, butanone, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, propylene glycol methyl ether, γ-butyrolactone, dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP). The aforementioned solvents can be used alone or in combination. There is no particular limitation on the amount of solvent used; in principle, it is sufficient to ensure that the components of the resin composition are uniformly dissolved or dispersed therein.

[0064] Without departing from the technical principles of this invention, the resin composition of this invention may further include selected components as needed to adaptively improve the processability of the resin composition during manufacturing, or to improve the physicochemical properties of electronic materials made from the resin composition. The selected components include, but are not limited to, additives selected from the following group: curing agents, curing accelerators, elastomers, fillers, dispersants, toughening agents, viscosity modifiers, flame retardants, plasticizers, and coupling agents. The aforementioned additives may be used alone or in any combination.

[0065] 4. Prepreg and metal foil laminate

[0066] This invention also provides a semi-cured sheet made from the above-described thermosetting resin composition, wherein the sheet is prepared by impregnating a substrate with the flame-retardant composition described above or coating the above-described thermosetting resin composition onto a substrate, and then drying the impregnated or coated substrate. The substrate may be a reinforcing material. Generally, the reinforcing material includes, but is 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, NE-glass, S-glass, L-glass, D-glass, T-glass, Q-glass, UN-glass, and spherical glass. 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 (e.g., Kevlar), polyester, liquid crystal polymers (e.g., liquid crystal polyester), polytetrafluoroethylene, ultra-high molecular weight polyethylene (UHMWPE), and high-modulus polypropylene (HMPP). Reinforcing materials can take the form of, but are not limited to, woven fabrics, non-woven fabrics, rovings, woven felt, and surface felt.

[0067] Furthermore, the present invention also provides a metal foil laminate made from the aforementioned prepreg, comprising a dielectric layer and a metal layer located on at least one surface of the dielectric layer, wherein the dielectric layer is formed from the aforementioned prepreg and the metal layer is formed from a metal foil. Specifically, multiple layers of the aforementioned prepreg can be stacked, and a metal foil (such as a copper foil) is stacked on at least one outer surface of the dielectric layer formed by the stacked prepregs to provide a laminate, and the laminate is subjected to a hot-pressing operation to obtain a metal foil laminate. Alternatively, the flame-retardant composition of the present invention can be directly coated onto a metal foil and the coated metal foil can be dried to obtain a metal foil laminate.

[0068] The outer metal foil of the aforementioned metal foil laminate can be further patterned to produce a printed circuit board.

[0069] 5. Examples

[0070] 5.1 Measurement Method

[0071] The present invention is further illustrated by the following specific embodiments, wherein the measuring instruments and methods used are as follows:

[0072] [Gel Permeation Chromatography (GPC) Test]

[0073] The prepared phenolic resin was dissolved in tetrahydrofuran at a concentration of 1.25% by weight, and then fed into a series of three columns connected in series at 40°C: one column C1 (model: TOSOH TSKgel G3000HxL), two columns C2 (model: TOSOH TSKgel G2000HxL), and one column C3 (model: TOSOH TSKgel G1000HxL). Column C1 was 30 cm long and had an inner diameter of 7.8 mm, and was filled with polystyrene-divinylbenzene with an average particle size of 5 μm and an average pore size of 7.5 nm. Columns C2 and C3 were also 30 cm long and had an inner diameter of 7.8 mm, and were filled with polystyrene-divinylbenzene with an average particle size of 5 μm and an average pore size of 2 nm. Column C3 was also 30 cm long and had an inner diameter of 7.8 mm, and was filled with polystyrene-divinylbenzene with an average particle size of 5 μm and an average pore size of 1.5 nm. Samples were collected and analyzed using a refractive index detector (Waters 2414RI detector). The peak values ​​in the resulting gel permeation chromatography chromatograms were sequentially labeled with their corresponding n values ​​according to elution times. Then, the peak area and related proportions representing each n value were calculated using the SISC32 software. The peak area was calculated as the integral area of ​​the line connecting the start and end points of the peak within a specified range.

[0074] [Viscosity Test]

[0075] The prepared phenolic resin was formulated into a 70% by weight solids solution of methyl ethyl ketone and placed in a constant temperature water bath at 25°C for 2 hours. The viscosity was then measured using a Brookfield viscometer, with the unit of viscosity being centipoise.

[0076] [Hydroxy Equivalent Test]

[0077] The hydroxyl equivalent of the prepared phenolic resin was measured according to JIS K 0070. The unit of hydroxyl equivalent is g / eq.

[0078] [Solvent Solubility and Preservation Test]

[0079] The prepared phenolic resin was formulated into a 70% by weight solids solution of methyl ethyl ketone and placed in a refrigerator at 5°C. The solution was observed daily for any precipitate formation, and the time of precipitate formation was recorded. If no precipitate formed after 70 days, it was recorded as "no precipitation".

[0080] [Processability Test]

[0081] The prepared phenolic resin was combined with epoxy resin (Changchun CNE200) to formulate a varnish with an epoxy equivalent to hydroxyl equivalent ratio of 1, and its gel time was controlled to be 100 to 120 seconds. A fiberglass cloth was impregnated in the varnish and then dried to prepare a fiberglass cloth prepreg. Five fiberglass cloth prepregs were stacked, and a copper foil was placed on the outermost layer on each side, followed by hot pressing. After hot pressing, the copper foil was removed by etching, and the surface of the fiberglass cloth was observed for any missing adhesive. If missing adhesive was observed, the processability test was not passed and recorded as "×"; if no missing adhesive was observed, the processability test was passed and recorded as "○".

[0082] 5.2. Preparation of Phenolic Resin

[0083] [Example 1]

[0084] In a four-necked flask equipped with a stirrer, thermometer, and condenser, 275.3 g of phenol and 1 g of p-toluenesulfonic acid were added. 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.

[0085] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, followed by washing with water. After washing, the resulting oil layer was heated under reduced pressure to remove unreacted phenol, yielding 386 grams of phenolic resin. The obtained phenolic resin had a weight-average molecular weight (Mw) of 1625, a number-average molecular weight (Mn) of 986, and a polydispersity index (PDI) of 1.648.

[0086] [Example 2]

[0087] 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. Then, 94.1 g of phenol and 84.5 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl were added again, and the reaction was maintained at 90°C for 2 hours to obtain the reaction product.

[0088] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, followed by washing with water. After washing, the resulting oil layer was heated under reduced pressure to remove unreacted phenol, yielding 152 grams of phenolic resin. The obtained phenolic resin had a weight-average molecular weight (Mw) of 3017, a number-average molecular weight (Mn) of 1048, and a polydispersity index (PDI) of 2.879.

[0089] [Example 3]

[0090] In a four-necked flask equipped with a stirrer, thermometer, and condenser, 275.3 g of phenol and 1 g of p-toluenesulfonic acid were added. 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.

[0091] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, followed by washing with water. After washing, the resulting oil layer was heated under reduced pressure to remove unreacted phenol, yielding 412 grams of phenolic resin. The obtained phenolic resin had a weight-average molecular weight (Mw) of 1758, a number-average molecular weight (Mn) of 1008, and a polydispersity index (PDI) of 1.744.

[0092] [Example 4]

[0093] In a four-necked flask equipped with a stirrer, thermometer, and condenser, 89.2 g of phenol and 1 g of p-toluenesulfonic acid were added. 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. Then, 336.0 g of phenol and 280.0 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl were added again, and the reaction was maintained at 100°C for 2 hours to obtain the reaction product.

[0094] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, followed by washing with water. After washing, the resulting oil layer was heated under reduced pressure to remove unreacted phenol, yielding 508 grams of phenolic resin. The obtained phenolic resin had a weight-average molecular weight (Mw) of 2318, a number-average molecular weight (Mn) of 967, and a polydispersity index (PDI) of 2.397.

[0095] [Example 5]

[0096] 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 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. Then, 247.3 g of phenol and 220.0 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl were added again, and the reaction was maintained at 100°C for 2 hours to obtain the reaction product.

[0097] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, followed by washing with water. After washing, the resulting oil layer was heated under reduced pressure to remove unreacted phenol, yielding 396 grams of phenolic resin. The obtained phenolic resin had a weight-average molecular weight (Mw) of 3373, a number-average molecular weight (Mn) of 1069, and a polydispersity index (PDI) of 3.155.

[0098] [Example 6]

[0099] 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.

[0100] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, followed by washing with water. After washing, the resulting oil layer was heated under reduced pressure to remove unreacted phenol, yielding 241 grams of phenolic resin. The obtained phenolic resin had a weight-average molecular weight (Mw) of 3906, a number-average molecular weight (Mn) of 1585, and a polydispersity index (PDI) of 2.464.

[0101] [Comparative Example 1]

[0102] In a four-necked flask equipped with a stirrer, thermometer, and condenser, 526.1 g of phenol and 1 g of p-toluenesulfonic acid were added. 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.

[0103] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, followed by washing with water. After washing, the resulting oil layer was heated under reduced pressure to remove unreacted phenol, yielding 432 grams of phenolic resin. The obtained phenolic resin had a weight-average molecular weight (Mw) of 902, a number-average molecular weight (Mn) of 661, and a polydispersity index (PDI) of 1.365.

[0104] [Comparative Example 2]

[0105] In a four-necked flask equipped with a stirrer, thermometer, and condenser, 182.7 g of phenol and 1 g of p-toluenesulfonic acid were added. 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.

[0106] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, followed by washing with water. After washing, the resulting oil layer was heated under reduced pressure to remove unreacted phenol, yielding 169 grams of phenolic resin. The obtained phenolic resin had a weight-average molecular weight (Mw) of 1102, a number-average molecular weight (Mn) of 746, and a polydispersity index (PDI) of 1.477.

[0107] [Comparative Example 3]

[0108] 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.

[0109] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, followed by washing with water. After washing, the resulting oil layer was heated under reduced pressure to remove unreacted phenol, yielding 254 grams of phenolic resin. The obtained phenolic resin had a weight-average molecular weight (Mw) of 4340, a number-average molecular weight (Mn) of 1738, and a polydispersity index (PDI) of 2.497.

[0110] [Comparative Example 4]

[0111] 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. Then, 247.3 g of phenol and 220.0 g of 4,4'-bis(chloromethyl)-1,1'-biphenyl were added again, and the reaction was maintained at 60°C for 2 hours.

[0112] The experimental results show that, in this comparative example, phenol and 4,4'-bis(chloromethyl)-1,1'-biphenyl could not react completely, and phenolic resin could not be obtained.

[0113] [Comparative Example 5]

[0114] 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.

[0115] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, followed by washing with water. After washing, the resulting oil layer was heated under reduced pressure to remove unreacted phenol, yielding 239 grams of phenolic resin. The obtained phenolic resin had a weight-average molecular weight (Mw) of 4102, a number-average molecular weight (Mn) of 1620, and a polydispersity index (PDI) of 2.532.

[0116] [Comparative Example 6]

[0117] 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 70 °C, 208.9 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.

[0118] Methyl isobutyl ketone was added to the reaction product to adjust the resin solids content to 50% by weight, followed by washing with water. After washing, the resulting oil layer was heated under reduced pressure to remove unreacted phenol, yielding 246 grams of phenolic resin. The obtained phenolic resin had a weight-average molecular weight (Mw) of 3845, a number-average molecular weight (Mn) of 1643, and a polydispersity index (PDI) of 2.340.

[0119] 5.3. Properties of Phenolic Resins

[0120] The properties of the phenolic resins of Examples 1 to 6 and Comparative Examples 1 to 6, including gel permeation chromatography properties, viscosity, hydroxyl equivalent, solvent solubility and preservation, and processability, were measured according to the measurement methods described above, and the results are recorded in Tables 1-1 and 1-2 below.

[0121] Table 1-1

[0122] Table 1-2

[0123]

[0124] *N / A indicates that phenolic resin cannot be produced.

[0125] As shown in Tables 1-1 and 1-2, the phenolic resins of Examples 1 to 6 of the present invention all exhibited a precipitation time of more than 21 days in the solvent, indicating good solvent solubility and preservation, and no resin deficiency, indicating good processability. In contrast, the phenolic resins of Comparative Examples 1 to 6 did not simultaneously provide the above-mentioned excellent properties. Comparative Examples 1 and 2 show that if 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 solvent solubility and preservation. Comparative Examples 3 and 5 to 6 show that if the B / A value is higher than the range specified in the present invention, the phenolic resin will exhibit resin deficiency and cannot be formed into the desired shape, indicating poor processability.

[0126] The above embodiments are merely illustrative of the principles and effects of the present invention and to illustrate its technical features, and are not intended to limit the scope of protection of the present invention. Any changes or arrangements that can be easily made by those skilled in the art without departing from the technical principles of the present invention are within the scope of the present invention. Therefore, the scope of protection of the present invention is as set forth in the claims.

Claims

1. A phenol resin, characterized by, which is represented by the following formula (I), wherein Ar is a hydroxyl group-containing aromatic group, each Ar can be the same or different; R is an aromatic group; m1 and m2 are each independently an integer of 0 to 4; n is greater than 0; and the sum of the peak areas of the fraction in which n is less than 5 is A, the sum of the peak areas of the fraction in which n is 5 or more is B, and the ratio of B to A (B / A) is 0.35 to 1.

32.

2. The phenol resin according to claim 1, wherein each Ar is independently a divalent group derived from a phenol, a cresol, a resorcinol, or a bisphenol compound.

3. The phenol resin of claim 1, wherein n is 1 to 400.

4. The phenol resin of claim 1, wherein the sum of the peak areas of the fraction in which n is 5 or more is B, and B accounts for 27% to 58% of the total area.

5. The phenol resin of claim 1, wherein the sum of the peak areas of the fraction in which n is less than 5 is A, and A accounts for 42% to 73% of the total area.

6. The phenol resin according to any one of claims 1 to 5, wherein The gel permeation chromatography is performed under the following test conditions: the phenolic resin is dissolved in tetrahydrofuran at a concentration of 1.25% by weight; separation is performed by feeding at a flow rate of 1.0 mL / min into a column C1, two columns C2, and a column C3 connected in series, wherein the column C1 has a length of 30 cm, an inner diameter of 7.8 mm, and is filled 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 has a length of 30 cm, an inner diameter of 7.8 mm, and is filled with polystyrene-divinylbenzene having an average particle size of 5 μm and an average pore size of 2 nm, and the column C3 has a length of 30 cm, an inner diameter of 7.8 mm, and is filled with polystyrene-divinylbenzene having an average particle size of 5 μm and an average pore size of 1.5 nm; The sample is collected and analyzed with a refractive index detector.

7. The phenol resin according to any one of claims 1 to 5, wherein A 70% by weight solids solution of the phenolic resin in methyl ethyl ketone has a viscosity of 900 to 4300 cps at 25°C.

8. The phenol resin according to any one of claims 1 to 5, wherein The phenolic resin has a hydroxyl equivalent weight of 220 to 245 g / eq.

9. A thermosetting resin composition, characterized by comprising: It comprises the phenolic resin according to any one of claims 1 to 8 and a solvent.

10. The thermosetting resin composition according to claim 9, wherein It further comprises an additive selected from the group consisting of a hardener, a hardening accelerator, an elastomer, a filler, a dispersant, a flexibilizer, a viscosity modifier, a flame retardant, a plasticizer, a coupling agent, and combinations thereof.

11. A prepreg, characterized by, It is prepared by impregnating or coating a substrate with the thermosetting resin composition according to claim 9 or 10, and drying the impregnated or coated substrate.

12. A metal foil laminate, characterized by comprising: It is prepared by laminating the prepreg according to claim 11 with a metal foil, or by coating a metal foil with the thermosetting resin composition according to claim 9 or 10 and drying the coated metal foil.

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