Agent of improving heat resistance agent for epoxy varnish with bismaleimide structure and Manufacturing method thereof

Abstract

The present invention relates to a heat resistance enhancer for epoxy-based varnish and a method for manufacturing the same. More specifically, the invention relates to an epoxy-based varnish and prepreg that can be used together with an epoxy resin applied to copper clad laminates (CCL), printed circuit boards (PCB), sealants for electronic components, adhesives, etc., to provide a low dielectric constant, a low dielectric loss, and excellent thermal properties.

Description

Technology Field

[0001] The present invention relates to a heat resistance enhancer of a novel structure used in conjunction with an epoxy resin applied to copper clad laminates (CCL), printed circuit boards (PCBs), sealants for electronic components, adhesives, etc., and a method for manufacturing the same. The invention relates to a heat resistance enhancer capable of improving the flexibility and heat resistance of cured products made of epoxy varnish while overcoming the low solubility of existing bismaleimide-based heat resistance enhancers in solvents, and a method for manufacturing the same. Background Technology

[0003] While the amount of information in electronic devices using printed circuit boards (PCBs) is becoming vast, component sizes are shrinking. Furthermore, as speed and density increase, circuit line widths are decreasing and more components are mounted per unit area, generating significant heat when transmitting high-speed signals. This heat causes problems such as board deformation due to differences in CTE between component materials. Additionally, with the complete ban on the use of Pb due to environmental regulations such as RoHS, soldering temperatures have risen to 20–40°C; consequently, materials requiring Lead-Free and high Glass Transition Temperature (T) g Characteristics such as high heat resistance are required.

[0004] In addition, in the high-frequency range of 10–28 GHz used in mobile devices, stations, routers, and data servers for 5G communication, significantly more heat is generated, requiring high heat resistance performance. Furthermore, low dielectric constant and dielectric loss are required to prevent loss of transmitted information.

[0005] Generally, the heat resistance of epoxy resins can be improved by increasing the crosslinking density between the epoxy resin and the curing agent; however, when novolak-based curing agents are used, there is a limit to the improvement in the heat resistance performance of the cured product itself, and there are problems where electrical properties such as dielectric constant and dielectric loss deteriorate due to the product's own high hygroscopicity and the formation of alcohol structures after curing.

[0006] In addition, styrene-maleic anhydride (SMA) resin exhibits characteristics of low dielectric constant and dielectric loss, but has poor heat resistance and thus has a problem with a high coefficient of thermal expansion.

[0007] As an alternative, commercially available active ester-based curing agents do not generate secondary alcohols, but due to their low molecular weight type, they have poor heat resistance and require improvement in electrical properties. In particular, excellent electrical properties are required for high-speed 5G communication, and with the recent development of electronic components and information and communication devices such as semiconductor substrates, printed circuit boards, and EMCs (Epoxy Molding Compounds), there is a demand for epoxy-based curable resins with enhanced physical properties.

[0008] In response to these requirements, bismaleimide compounds are being applied as heat resistance enhancers. However, existing heat resistance enhancers have a problem with low solubility in solvents, which limits their range of application and the selection of solvents when preparing epoxy varnish. Prior art literature

[0010] Republic of Korea Published Patent No. 10-2007-0076083 (Publication Date: July 24, 2007) Republic of Korea Published Patent No. 10-2021-0125482 (Publication Date: October 18, 2021) The problem to be solved

[0011] The present invention has been devised to solve the aforementioned problems. The present invention aims to provide a heat resistance enhancer capable of producing an epoxy-based varnish having a low dielectric constant while increasing the heat resistance and flexibility of the epoxy-based varnish and its cured product. Specifically, the purpose of the present invention is to provide a heat resistance enhancer for epoxy-based varnish, a method for manufacturing the same, and an epoxy-based varnish and an epoxy-based curable resin (or prepreg) using the same. means of solving the problem

[0013] The present invention, for solving the above-mentioned problem, comprises a heat resistance enhancer for epoxy-based varnish, which includes an oligomer represented by the following chemical formula 1.

[0014] [Chemical Formula 1]

[0015]

[0016] In Chemical Formula 1, R 1 is a hydrogen atom or a methyl group, and R 2 is C1~C 12 straight-chain alkyl groups or C3~C 12 It is a branched alkyl group, and A is , or and, n is 0 ~ 3, and X is is, R 3 is an aromatic ring compound without carbon atoms or substituents, and R 4 and R 5 Each is independently a hydrogen atom or a methyl group, and R 6 and R 9 Each is independently a hydrogen atom, a methyl group, or an ethyl group, and * indicates a bonding site.

[0017] As a preferred embodiment of the present invention, A of Formula 1 is and, , n can be 0 to 3.

[0018] As a preferred embodiment of the present invention, the oligomer may have a weight-average molecular weight of 800 to 2,000 and a curing time of 80 to 500 seconds.

[0019] As a preferred embodiment of the present invention, A of Formula 1 is or is, and X is and R 3 is a carbon atom, and R 4 and R 5 is a methyl group, and R 6 and R 9 Each can independently be a hydrogen atom or a methyl group.

[0020] As a preferred embodiment of the present invention, the oligomer may have a weight-average molecular weight of 1,000 to 2,600 and a curing time of 100 to 550 seconds.

[0021] As a preferred embodiment of the present invention, the heat resistance enhancer of the present invention can satisfy a solubility of 100% or more when measuring solubility by Equation 1, by measuring the amount of solvent added (g) that generates precipitates when a solvent is added and stirred at 25°C after preparing a solution by completely dissolving 2.5g of the heat resistance enhancer in 2.5g of DMF (Dimethylformamide).

[0022] [Equation 1]

[0023] Solubility (%) = {Amount of solvent added (g) / Weight of heat resistance enhancer (g)} × 100%

[0024] As a preferred embodiment of the present invention, the solvent added in Formula 1 may include one or more selected from DMAc (Dimethylacetamide), DMF (Dimethylformaimide), MEK (methylethyl ketone), MIBK (methyl isobutyl ketone), acetone, and cyclohexanone; one or more selected from PGMEA (Propylene glycol methyl ether acetate) and ethyl acetate; and one or more selected from xylene.

[0026] In addition, the present invention relates to a method for manufacturing a heat resistance enhancer as described above, comprising a process comprising: a first step of mixing a maleimide compound represented by Chemical Formula 2 or Chemical Formula 3 and a styrene-based compound represented by Chemical Formula 4 in a solvent and heating the mixed solution while stirring; a second step of adding a reaction catalyst to the heated solution and raising the temperature to the main reaction temperature and performing a first main reaction; a third step of adding a vinyl-based compound represented by Chemical Formula 5 and a reaction catalyst after the first main reaction is completed and performing a second main reaction; and a fourth step of cooling to 15 to 30°C after the second main reaction is completed to obtain an oligomer represented by Chemical Formula 1 containing a solvent.

[0027] [Chemical Formula 2]

[0028]

[0029] In Chemical Formula 2, n is 0 to 3.

[0030] [Chemical Formula 3]

[0031]

[0032] In Chemical Formula 3, X is is, R 3 is an aromatic ring compound without carbon atoms or substituents, and R 4and R 5 Each is independently a hydrogen atom or a methyl group, and R 6 and R 9 Each is independently a hydrogen atom, a methyl group, or an ethyl group, and

[0033] [Chemical Formula 4]

[0034]

[0035] R of Chemical Formula 4 1 It is a hydrogen atom or a methyl group.

[0036] [Chemical Formula 5]

[0037]

[0038] R of chemical formula 5 2 is C1~C 12 straight-chain alkyl groups or C3~C 12 It is a pulverized alkyl group.

[0039] As a preferred embodiment of the present invention, the temperature of the first stage of heating may be 35 to 50°C.

[0040] As a preferred embodiment of the present invention, the primary main reaction temperature of the second stage and the secondary main reaction temperature of the third stage may be 90 to 120°C.

[0041] As a preferred embodiment of the present invention, the mixed solution of the first step may comprise 100 to 140 parts by weight of the styrene-based compound and 180 to 250 parts by weight of the solvent, with respect to 100 parts by weight of the maleimide compound.

[0042] As a preferred embodiment of the present invention, the amount of vinyl compound added in step 3 may be 40 to 200 parts by weight with respect to 100 parts by weight of the maleimide compound in step 1.

[0043] As a preferred embodiment of the present invention, the yield of the oligomer (heat resistance enhancer) produced by the manufacturing method of the present invention may be 70% or more and the purity may be 70% or more.

[0044] In addition, the present invention relates to a prepreg comprising a cured product of an epoxy-based varnish containing the heat resistance enhancer described above.

[0045] As a preferred embodiment of the present invention, the epoxy-based varnish may comprise an epoxy resin, a physical property enhancer, a curing agent, a curing accelerator, and a solvent.

[0046] As a preferred embodiment of the present invention, the solvent may include one or more selected from DMAc (Dimethylacetamide), DMF (Dimethylformaimide), MEK (methylethyl ketone), MIBK (methyl isobutyl ketone), acetone, and cyclohexanone; one or more selected from PGMEA (Propylene glycol methyl ether acetate) and ethyl acetate; and one or more selected from xylene.

[0047] As a preferred embodiment of the present invention, the prepreg may have a glass transition temperature (Tg) of 210°C to 235°C when measured using a dynamic mechanical analyzer (DMA).

[0048] As a preferred embodiment of the present invention, the dielectric constant (D) of the cured material having a thickness of 0.8 to 1 mm is measured using an impedance analyzer (Agilent E4991B) at a measurement frequency of 1 GHz and a measurement temperature of 25°C to 27°C. k ) and dielectric loss (D f When measuring ), permittivity (D k ) is 3.50 or less, and dielectric loss (D f ) may be 0.015 or less.

[0049] As a preferred embodiment of the present invention, the epoxy resin may be a phenol novolac-based epoxy resin. Effects of the invention

[0051] The heat resistance enhancer of the present invention has excellent solubility in various solvents and, when applied to an epoxy-based varnish, has the effect of improving not only the heat resistance of the cured product but also its flexibility. Furthermore, since it does not degrade the electrical properties of the cured product, it is possible to provide a prepreg having low dielectric properties. Thus, an epoxy-based varnish to which the heat resistance enhancer of the present invention is applied is suitable for use in the manufacture of products such as printed circuit boards (CCL, Copper clad laminate), sealants for electronic components, and adhesives that require low dielectric and high heat resistance. Specific details for implementing the invention

[0053] The present invention will be described in more detail below.

[0054] The present invention relates to a heat resistance enhancer capable of satisfying low dielectric properties while improving the heat resistance and flexibility of such existing epoxy-based varnish (curable resin), wherein the heat resistance enhancer of the present invention comprises an oligomer represented by the following chemical formula 1.

[0055] [Chemical Formula 1]

[0056]

[0057] In Chemical Formula 1, R 1 is a hydrogen atom or a methyl group, preferably a methyl group. And, R of Chemical Formula 1 2 is C1~C 12 straight-chain alkyl groups or C3~C 12 It is a branched alkyl group, preferably R 2 is C5~C 10 It is a straight-chain alkyl group.

[0058] In addition, A of Chemical Formula 1 is , or and n is 0 to 3.

[0059] And, the above X is is, R 3is an aromatic ring compound without a carbon atom or substituents, preferably a carbon atom. And, the above R 4 and R 5 Each is independently a hydrogen atom or a methyl group, preferably a methyl group.

[0060] In addition, the above R 6 and R 9 Each is independently a hydrogen atom, a methyl group, or an ethyl group, preferably a hydrogen atom or a methyl group, and more preferably a methyl group.

[0061] And, the above "*" indicates a binding site with another chemical structure or compound.

[0062] For a preferred embodiment of the oligomer of the present invention, in Formula 1, A is And, n can be 0 to 3, and a can be a compound in which a is 0 to 3. For example, in Formula 1, all compounds in which a of A is 0, 1, 2 and 3 may be included, and in this case, 20 to 40 wt% of a compound in which a is 1, 10 to 30 wt% of a compound in which a is 2, 2 to 10 wt% of a compound in which a is 3, and the remaining amount of a compound in which a is 0 among 100 wt% may be included, and preferably 25 to 35 wt% of a compound in which a is 1, 12 to 20 wt% of a compound in which a is 2, 3 to 8 wt% of a compound in which a is 3, and the remaining amount of a compound in which a is 0 among 100 wt% may be included.

[0063] And, this oligomer may have a weight-average molecular weight of 800 to 2,000, preferably 800 to 1,200, and a curing time of 80 to 500 seconds, preferably 150 to 450 seconds.

[0064] In addition, as another preferred embodiment of the above oligomer, A in Chemical Formula 1 is or is, and X is and R 3is a carbon atom, and R 4 and R 5 is a methyl group, and R 6 and R 9 Each can independently be a hydrogen atom or a methyl group. And, the oligomer has a weight-average molecular weight of 1,000 to 2,600, preferably a weight-average molecular weight of 1,200 to 1,600, and a curing time of 100 to 550 seconds, preferably a curing time of 150 to 500 seconds.

[0065] The oligomer, which is a heat resistance enhancer of the present invention described above, has excellent solubility in solvents such as DMAc (Dimethylacetamide), DMF (Dimethylformaimide), MEK (methylethyl ketone), MIBK (methyl isobutyl ketone), acetone, and cyclohexanone; acetate solvents such as PGMEA (Propylene glycol methyl ether acetate) and ethyl acetate; and / or xylene. When measured by the following method, it can satisfy a solubility of 100.00% or more, preferably 500.00% or more, and even more preferably 2,500% to 4,400%.

[0066] The above solubility was measured by the method of measuring the amount of solvent (g) that generates precipitates when the solvent is added and stirred at 25°C after preparing a solution by completely dissolving 2.5g of the above physical property improver in 2.5g of DMF (Dimethylformamide).

[0067] [Equation 1]

[0068] Solubility (%) = {Amount of solvent added (g) / Weight of property improver (g)} × 100%

[0070] The oligomer (heat resistance enhancer) of the present invention described above can be manufactured in the following manner.

[0071] The oligomer (heat resistance enhancer) of the present invention can be manufactured by performing a process comprising: a first step of mixing a maleimide compound represented by Chemical Formula 2 or Chemical Formula 3 and a styrene-based compound represented by Chemical Formula 4 in a solvent and heating the mixed solution while stirring; a second step of adding a reaction catalyst to the heated solution and raising the temperature to the main reaction temperature and performing a first main reaction; a third step of adding a vinyl-based compound represented by Chemical Formula 5 and a reaction catalyst after the first main reaction is completed and performing a second main reaction; and a fourth step of cooling to 15 to 30°C after the second main reaction is completed to obtain an oligomer represented by Chemical Formula 1 containing a solvent.

[0072] [Chemical Formula 2]

[0073]

[0074] In Chemical Formula 2, a compound in which n is 0 to 3 and a is 0 to 3 may be mixed. For example, in Chemical Formula 2, all compounds in which a is 0, 1, 2, and 3 may be included, wherein 20 to 40 wt% of a compound in which a is 1, 10 to 30 wt% of a compound in which a is 2, 2 to 10 wt% of a compound in which a is 3, and the remaining amount of a compound in which a is 0 among 100 wt% may be included, and preferably 25 to 35 wt% of a compound in which a is 1, 12 to 20 wt% of a compound in which a is 2, 3 to 8 wt% of a compound in which a is 3, and the remaining amount of a compound in which a is 0 among 100 wt% may be included.

[0075] [Chemical Formula 3]

[0076]

[0077] The above X is is, R 3is an aromatic ring compound without a carbon atom or substituents, preferably a carbon atom. And, the above R 4 and R 5 Each is independently a hydrogen atom or a methyl group, preferably a methyl group.

[0078] [Chemical Formula 4]

[0079]

[0080] R of Chemical Formula 4 1 It is a hydrogen atom or a methyl group, preferably a methyl group.

[0081] [Chemical Formula 5]

[0082]

[0083] R of chemical formula 5 2 is C1~C 12 straight-chain alkyl groups or C3~C 12 It is a branched alkyl group, preferably R 2 is C5~C 10 It is a straight-chain alkyl group.

[0084] The mixed solution of step 1 comprises 100 to 140 parts by weight of the styrene-based compound and 180 to 250 parts by weight of the solvent per 100 parts by weight of the maleimide compound, preferably 110 to 125 parts by weight of the styrene-based compound and 190 to 230 parts by weight of the solvent per 100 parts by weight of the maleimide compound, and more preferably 112 to 120 parts by weight of the styrene-based compound and 190 to 220 parts by weight of the solvent per 100 parts by weight of the maleimide compound. At this time, if the amount of styrene-based compound used is less than 100 parts by weight, the yield of the final oligomer may be too low, and if more than 140 parts by weight is used, a large amount of unreacted material remains, making it uneconomical. In addition, if the amount of the solvent used is less than 180 parts by weight, there may be problems such as polymerization and gelation or difficulty in process control, and if it exceeds 250 parts by weight, the amount of unreacted monomer increases, the purity decreases, and there may be uneconomical problems, so it is appropriate to use it within the above range.

[0085] In addition, the solvent of the first step above may include one or more selected from DMAc (Dimethylacetamide), DMF (Dimethylformaimide), MEK (methylethyl ketone), MIBK (methyl isobutyl ketone), acetone, and cyclohexanone; one or more selected from PGMEA (Propylene glycol methyl ether acetate) and ethyl acetate; and one or more selected from xylene; and preferably, it is advantageous in terms of raw material solubility, synthetic product solubility, and process stability to include one or more selected from DMAc, MIBK (methyl isobutyl ketone), and PGMEA (Propylene glycol methyl ether acetate).

[0086] In addition, in the first step, the mixed solution is heated to 35 to 50°C, preferably 38 to 45°C, while stirring, and then the second step process is performed. The reason for heating is to ensure that the reaction proceeds under the same conditions throughout all four seasons. If the temperature is below 35°C, there may be a problem with differences in reactivity during the summer, and if it exceeds 50°C, there may be a problem with difficulty in controlling the exothermic reaction due to the introduction of the catalyst at high temperatures.

[0087] Next, step 2 is a process of adding a reaction catalyst to a heated solution, raising the temperature to a main reaction temperature, and performing a primary main reaction, wherein the reaction catalyst may include one or more selected from di-t-butyl peroxide, dicumyl peroxide, 75% BPO (Benzoyl peroxide), and AIBN (Azobisisobutyronitrile).

[0088] In addition, the main reaction temperature of the second step can be carried out at 90 to 120°C, preferably at 95 to 110°C. If the main reaction temperature is below 90°C, the synthesis rate of the intermediate to be manufactured is too low, which may result in low yield and purity of the final oligomer. If the temperature exceeds 120°C, there may be problems such as polymerization, gelation, or difficulty in process control.

[0090] Next, step 3 is a process of reacting the primary reaction product with a vinyl compound represented by Chemical Formula 5 after the completion of the primary main reaction, and the secondary main reaction can also be carried out by adding a reaction catalyst, just like the primary main reaction. At this time, one or more selected from di-t-butyl peroxide, dicumyl peroxide, 75% BPO (Benzoyl peroxide), and AIBN (Azobisisobutyronitrile) can be used as reaction catalysts.

[0091] Also, the second main reaction temperature is the same as the first main reaction temperature range.

[0092] In addition, the amount of vinyl compound added in the third step can be 40 to 200 parts by weight, preferably 45 to 170 parts by weight, relative to 100 parts by weight of the maleimide compound in the first step. If the amount of vinyl compound used is less than 40 parts by weight, the dielectric performance during prepreg manufacturing is lowered and the problem of precipitation in the solvent occurs due to low solubility. Even if more than 200 parts by weight are used, there is no increase in yield, and instead, unreacted monomers remain, which may lower the purity. Therefore, it is appropriate to use it within the above range.

[0094] Next, step 4 is a process of completing the secondary main reaction and cooling the main reaction solution containing the reaction product to room temperature (15 to 30°C) to obtain an oligomer represented by Chemical Formula 1 from a solution containing a solvent.

[0095] In addition, the solution obtained in step 4 may be degassed to remove the solvent to obtain an oligomer represented by Chemical Formula 1, and further washing and / or drying processes may be performed.

[0096] Through this method, the oligomer represented by the above chemical formula 1 can be produced with a yield of 70% or more and a purity of 70% or more, preferably with a yield of 80% or more and a purity of 80% or more, and more preferably with a yield of 90% or more and 90% or more.

[0097] In addition, the oligomer (heat resistance enhancer) of the present invention prepared in this manner has excellent solubility in various solvents. A preferred example of the solvent may include one or more selected from DMAc (Dimethylacetamide), DMF (Dimethylformaimide), MEK (methylethyl ketone), MIBK (methyl isobutyl ketone), acetone, and cyclohexanone; one or more selected from acetate solvents including PGMEA (Propylene glycol methyl ether acetate) and ethyl acetate; and xylene; and preferably, may include one or more selected from DMAc, MIBK (methyl isobutyl ketone), and PGMEA (Propylene glycol methyl ether acetate).

[0099] The heat resistance enhancer of the present invention described above can provide a prepreg comprising a cured product of an epoxy-based varnish, and the prepreg can have low dielectric strength, high heat resistance, and excellent flexibility.

[0100] In addition, the epoxy-based varnish may include an epoxy resin, a heat resistance enhancer, a curing agent, a curing accelerator, and a solvent. At this time, the solvent may include one or more selected from DMAc (Dimethylacetamide), MEK (methylethyl ketone), acetone, PGMEA (Propylene glycol methyl ether acetate), and xylene, and the epoxy resin may preferably be a phenol novolak-based epoxy resin.

[0101] In addition, the prepreg (cured product) has excellent heat resistance, with a glass transition temperature (Tg) of 210°C to 235°C, preferably 214°C to 230°C, and more preferably 215°C to 228°C when measured using a dynamic mechanical analyzer (DMA).

[0102] In addition, when the dielectric constant and dielectric loss of the above prepreg (cured material) are measured using an impedance analyzer (Agilent E4991B) at a measurement frequency of 1 GHz and a measurement temperature of 25℃ to 27℃ when the thickness is 0.8 to 1 mm, the dielectric constant (D k , or dielectric constant) 3.50 or less and dielectric loss (D f ) may be 0.015 or less, and preferably the permittivity (D k ) 2.50 ~ 3.40 and dielectric loss (D f ) It has a range of 0.005 to 0.010, so it can have excellent low dielectric properties.

[0103] Accordingly, by using the above curing agent, it is possible to provide prepregs used in the manufacture of various products requiring high heat resistance and low dielectric constant, such as copper clad laminates (CCL), printed circuit boards (PCBs), sealants for electronic components, and adhesives.

[0105] The present invention will be explained in more detail below through examples, but the following examples are not intended to limit the scope of the invention and should be interpreted as being for the purpose of aiding understanding of the invention.

[0106] [Example]

[0107] Example 1: Preparation of a heat resistance enhancer

[0108] An oligomer (heat resistance enhancer) was synthesized by carrying out the reaction according to Reaction Scheme 1-1 through the following process.

[0109] [Reaction Equation 1-1]

[0110]

[0111] 200g of DMAc (Dimethyl acetamide), 100g of a maleimide compound represented by the following chemical formula 2-1, and 116g of a styrene-based compound represented by the following chemical formula 4-1 are added to a kettle equipped with a thermometer, a cooling tube, and a stirrer, and stirring is performed under a nitrogen atmosphere, and 40 It rose to a high temperature.

[0112] [Chemical Formula 2-1]

[0113]

[0114] In Chemical Formula 2-1, a is 0 to 3, and the compound represented by Chemical Formula 2-1 is a compound in which a is 0 to 3 is mixed, and the compound represented by Chemical Formula 2-1 contains 25 to 35% of a compound in which a is 1, 12 to 20% of a compound in which a is 2, 3 to 8% by weight of a compound in which a is 3, and the remaining amount of a compound in which a is 0 among 100% by weight.

[0115] [Chemical Formula 4-1]

[0116]

[0117] In chemical formula 4-1, R 1 It is a hydrogen atom.

[0118] Next, when the temperature reached 40℃, 0.5g of di-t-butyl peroxide (reaction catalyst) was added, and the temperature was raised to 100℃. After the temperature was raised, the first main reaction was carried out for 2 hours while maintaining this temperature.

[0119] Next, while maintaining the primary main reaction temperature, 156 g of a vinyl compound represented by the following chemical formula 5-1 and 0.5 g of di-t-butyl peroxide were added to the reaction solution in which the primary main reaction was completed, and the secondary main reaction was carried out at 100°C for 3 hours.

[0120] When the second main reaction was completed, the solution was cooled to about 22–24°C to prepare a solution (resin) containing an oligomer represented by the following chemical formula 1-1, having a weight-average molecular weight of 1,050 and containing a solvent.

[0121] [Chemical Formula 5-1]

[0122]

[0123] R of Chemical Formula 5-1 2 is a C8 straight-chain alkyl group.

[0124] [Chemical Formula 1-1]

[0125]

[0126] In chemical formula 1-1, R 1 is a hydrogen atom, and R 2 is a C8 straight-chain alkyl group, and A is And, a is 0 to 3, and the compound represented by Chemical Formula 1- is a compound in which a is 0 to 3 is mixed, and the compound represented by Chemical Formula 1-1 includes 25 to 35% of the compound where a is 1, 12 to 20% of the compound where a is 2, 3 to 8% by weight of the compound where a is 3, and the remaining amount of the compound where a is 0 among 100% by weight.

[0128] Example 2: Preparation of a heat resistance enhancer

[0129] An oligomer represented by Chemical Formula 1-1 was prepared in the same manner as in Example 1 above, but using 78g of a vinyl compound represented by Chemical Formula 5-1, to obtain a solution (resin) containing an oligomer with a weight-average molecular weight of 950.

[0131] Example 3: Preparation of a heat resistance enhancer

[0132] An oligomer represented by Chemical Formula 1-1 was prepared in the same manner as in Example 1 above, but using 47g of a vinyl compound represented by Chemical Formula 5-1, to obtain an oligomer with a weight-average molecular weight of 850.

[0135] Example 4: Preparation of a heat resistance enhancer

[0136] An oligomer represented by Chemical Formula 1-1 was prepared in the same manner as in Example 1 above, but 94g of a vinyl compound represented by Chemical Formula 5-2 was used instead of the vinyl compound represented by Chemical Formula 5-1, and an oligomer-containing solution (resin) with a weight-average molecular weight of about 1,000 was obtained.

[0137] [Chemical Formula 5-2]

[0138]

[0139] R of Chemical Formula 5-1 2 is a C2 straight-chain alkyl group.

[0141] Example 5: Preparation of a heat resistance enhancer

[0142] An active ester compound was synthesized by performing the reaction according to Reaction Scheme 1-2 through the following process.

[0143] [Reaction Equation 1-2]

[0144]

[0145] 200g of DMAc (Dimethyl acetamide), 100g of a maleimide compound represented by the following chemical formula 3-1, and 94g of a styrene-based compound represented by the following chemical formula 4-1 are added to a kettle equipped with a thermometer, a cooling tube, and a stirrer, and stirring is performed under a nitrogen atmosphere, and 40 It rose to a high temperature.

[0146] [Chemical Formula 3-1]

[0147]

[0148] In Chemical Formula 3, X is is, R 3 is a carbon atom, and R 4 and R 5 is a methyl group, and R 6 and R 7 is a methyl group, and R 8 and R 9 is an ethyl group.

[0149] [Chemical Formula 4-1]

[0150]

[0151] In chemical formula 4-1, R 1 It is a hydrogen atom.

[0152] Next, when the temperature reached 40℃, 0.5g of di-t-butyl peroxide (reaction catalyst) was added, and the temperature was raised to 100℃. After the temperature was raised, the primary main reaction was carried out for 2 hours while maintaining this temperature.

[0153] Next, while maintaining the primary main reaction temperature, 127 g of a vinyl compound represented by the following chemical formula 5-1 and 0.5 g of di-t-butyl peroxide were added to the reaction solution in which the primary main reaction was completed, and the secondary main reaction was carried out at 100°C for 3 hours.

[0154] When the second main reaction was completed, the solution was cooled to 22–24°C to prepare a solution (resin) containing an oligomer represented by the following chemical formula 1-2, having a weight-average molecular weight of 1,300 and containing a solvent.

[0155] [Chemical Formula 5-1]

[0156]

[0157] R of Chemical Formula 5-1 2 is a C8 straight-chain alkyl group.

[0158] [Chemical Formula 1-2]

[0159]

[0160] In chemical formula 1-1, R 1 is a hydrogen atom, and R 2 is a C8 straight-chain alkyl group, and X is is, R 3 is a carbon atom, and R 4 and R 5 is a methyl group, and R 6 and R 7 is a methyl group, and R 8 and R 9 is an ethyl group.

[0162] Comparative Examples 1 to 4

[0163] An oligomer represented by Chemical Formula 1-1 was prepared using the same composition as in Example 1 above, but an oligomer-containing solution (resin) was prepared with different compositional contents as shown in Table 2 below, and Comparative Examples 1 to 4 were carried out respectively.

[0165] Experimental Example 1: Measurement of Purity and Yield

[0166] The above The purity and yield of the oligomers (heat resistance enhancers) prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were measured, and the results are shown in Tables 1 and 2 below.

[0167] At this time, the yield was calculated based on Equation 1 below, and the purity of the product was confirmed by measuring unreacted material using HPLC (High Performance Liquid Chromatography).

[0168] [Equation 1]

[0169] Yield (%) = (Reaction product yield / Reactant input amount) × 100%

[0170] Classification (weight part) Example 1 Example 2 Example 3 Example 4 Example 5 Maleimide compounds Chemical formula 2-1 100 100 100 100 - Chemical formula 3-1 - - - - 100 Styrene compounds Chemical formula 4-1 116 116 116 116 94 solvent DMAc 200 200 200 200 200 vinyl compounds Chemical formula 5-1 156 78 47 - 127 Chemical Formula 5-2 - - - 94 - weight-average molecular weight Approximately 1,050 Approximately 950 About 850 About 1,000 Approximately 1,300 Curing time 270 220 200 250 330 transference number(%) 98 99 99 98 96 water(%) 98 99 99 98 96

[0171] Classification (weight part) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Maleimide compounds Chemical formula 2-1 100 100 100 100 Chemical formula 3-1 - - - - Styrene compounds Chemical formula 4-1 58 58 116 - solvent DMAc 200 200 200 200 vinyl compounds Chemical formula 5-1 156 78 - 156 Chemical Formula 5-2 - - - - weight-average molecular weight About 600 About 500 About 700 About 400 Curing time 740 650 30 Not hardened transference number(%) 85 92 99 40 water(%) 85 92 99 40

[0173] Experimental Example 2: Evaluation of Solubility in Solvents

[0174] After obtaining the oligomers by degassing the oligomer solutions (resins) prepared in Examples 1 to 5 and Comparative Examples 1 to 4, an experiment was performed to evaluate the solubility of each of these oligomers in a solvent, and the results are shown in Table 3 below.

[0175] DMAc (Dimethylacetamide), MEK (methylethyl ketone), acetone, PGMEA (Propylene glycol methyl ether acetate), and xylene were used as solvents.

[0176] Control group 1 used the maleimide compound represented by Chemical Formula 2-1 used in Examples 1 to 4.

[0177] In addition, Control Group 2 used the maleimide compound represented by Chemical Formula 3-1 used in Example 5.

[0178] In addition, the solubility evaluation was performed by completely dissolving 2.5g of the sample oligomer in 2.5g of DMF (Dimethylformamide) to prepare a solution, and then adding the solvent to the solution at 25℃ and stirring to measure the amount of solvent added (g) that generates precipitates, and the solubility (%) was calculated according to Equation 1.

[0179] [Equation 1]

[0180] Solubility (%) = {Amount of solvent added (g) / Weight of heat resistance enhancer (g)} × 100%

[0181] division DMAc MEK acetone PGMEA Xylene Example 1 4,300% 3,100% 2,500% 2,200% 1,800% Example 2 4,100% 3,000% 2,400% 2,100% 1,700% Example 3 3,800% 3,800% 2,200% 2,000% 1,450% Example 4 3,900% 2,900% 2,300% 2,050% 1,570% Example 5 3,100% 2,500% 2,100% 1,500% 730% Comparative Example 1 2,200% 1,000% 1,200% 220% 80% Comparative Example 2 1,900% 770% 820% 200% 50% Comparative Example 3 1,200% 330% 410% 50% 10% or less Comparative Example 4 600% 200% 250% 45% 10% or less Control group 1 1,500% 500% 610% 130% 10% or less Control group 2 800% 280% 360% 50% 10% or less

[0182] Looking at the solubility measurement results in Table 3 above, it was confirmed that Examples 1 to 5 had very high solubility for all solvents, including DMAc, MEK, acetone, PGMEA, and xylene.

[0183] In contrast, Comparative Examples 1 and 2 showed low results with less than 100% solubility for xylene, Comparative Examples 3 and 4 showed very low solubility for xylene, and compared to Examples 1 to 5, showed relatively very low solubility for other solvents.

[0185] Preparation Example 1: Preparation of prepreg and laminate

[0186] A varnish was prepared by adding and mixing 200g of epoxy resin (Kukdo Chemical, YDPN-638), 100g of the oligomer (heat resistance enhancer) prepared in Example 1, 110g of phenol novolak resin (curing agent), 3.0g of dicyandiamide as a curing catalyst, 0.3g of 2-MI (2-Mehtyl imidazole, 10% MCS), and 200g of DMAc as a solvent.

[0187] Next, glass cloth (#2116) was impregnated with the varnish prepared above, and then dried in a drying oven at 160°C for 10 minutes to volatilize the solvent. After that, four sheets of resin-impregnated glass cloth were laminated, and then cured for 2 hours at 200°C and 5 MPa to produce a four-layer laminated board as a cured product (prepreg).

[0189] Preparation Examples 2–5 and Comparative Preparation Examples 1–6

[0190] After preparing a varnish in the same manner as in Preparation Example 1 above, a laminate was prepared under the same conditions and method, but an oligomer (heat resistance enhancer) was used as shown in Tables 4 and 5 below, or bismaleimide (product name BMI-2300 or product name BMI-70) was used instead of the oligomer.

[0191]

[0192] Experimental Example 3: Measurement of Glass Transition Temperature, Decomposition Temperature, Dielectric Constant, and Dielectric Loss of Prepreg (Curing Material)

[0193] The solubility of the varnish in solvents was evaluated by determining whether precipitates formed in the varnish used to manufacture the prepregs (cured products) of the manufacturing examples and comparative manufacturing examples; it was evaluated as excellent if no precipitates formed and poor if precipitates formed.

[0194] also, The glass transition temperature, decomposition temperature, dielectric constant, and dielectric loss of the prepreg used in the manufacture of the above laminate were measured, and the results are shown in Tables 4 and 5 below.

[0195] The glass transition temperature was analyzed using differential scanning calorimetry (DSC) and dynamic mechanical analyzer (DMA) under a heating condition of 20°C / min.

[0196] The decomposition temperature was analyzed using a thermogravimetric analyzer (TGA) under a heating condition of 20℃ / min.

[0197] Permittivity and dielectric loss were analyzed using an impedance analyzer (Agilent E4991B) at 1 GHz and a measurement temperature of 25–27°C.

[0198] Classification (g) Preparation Example 1 Preparation Example 2 Preparation Example 3 Preparation Example 4 Preparation Example 5 Comparative Manufacturing Example 1 Comparative Manufacturing Example 2 Epoxy resin (BPA Novolac epoxy) 200 200 200 200 200 200 200 Oligomer (heat resistance enhancer) Example 1 100 - - - - - - Example 2 - 100 - - - - - Example 3 - - 100 - - - - Example 4 - - - 100 - - - Example 5 - - - - 100 - - Comparative Example 1 - - - - - 100 - Comparative Example 2 - - - - - - 100 Phenol novolak resin (curing agent) 110 110 110 110 110 110 110 curing catalyst dicyandiamide 3.0 3.0 3.0 3.0 3.0 3.0 3.0 2MI 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Varnish solubility excellence excellence excellence excellence excellence excellence excellence prepreg properties DSC(Tg,℃) 190 195 198 196 199 176 180 DMA(Tg,℃) 217 221 225 223 227 200 204 Decomposition temperature (Td 5%,°C) 310 313 317 314 320 300 303 Permittivity (D k , @1GHz) 3.22 3.25 3.27 3.26 3.30 3.27 3.29 Dielectric loss (D f , @1GHz) 0.007 0.008 0.009 0.008 0.009 0.010 0.011

[0199] Classification (g) Comparative Manufacturing Example 3 Comparative Manufacturing Example 4 Comparative Manufacturing Example 5 Comparative Manufacturing Example 6 Comparative Manufacturing Example 7 Comparative Manufacturing Example 8 Epoxy resin (BPA Novolac epoxy) 200 200 200 200 200 200 oligomer Comparative Example 3 100 - - - - - Comparative Example 4 - 100 - - - - Bismaleimide BMI-2300 - - 100 - 20 - BMI-70 - - - 100 - 20 Phenol novolak resin (curing agent) 110 110 110 110 110 110 curing catalyst dicyandiamide 3.0 3.0 3.0 3.0 3.0 3.0 2MI 0.3 0.3 0.3 0.3 0.3 0.3 Varnish solubility excellence Bad (precipitation) Bad (precipitation) Bad (precipitation) excellence excellence prepreg properties DSC(Tg,℃) 185 155 - - 175 177 DMA(Tg,℃) 210 179 - - 197 202 Decomposition temperature (Td 5%,°C) 305 290 - - 295 294 Permittivity (D k , @1GHz) 3.40 3.35 - - 3.42 3.47 Dielectric loss (D f , @1GHz) 0.016 0.013 - - 0.020 0.022

[0200] Looking at the measurement results in Tables 4 and 5 above, it was confirmed that Preparation Examples 1 to 5 not only exhibited excellent varnish solubility, but also that the prepregs possessed high heat resistance with a glass transition temperature of 210°C or higher based on DMA, and furthermore, the dielectric constant (D k , or dielectric constant) 3.50 or less and dielectric loss (D f It was confirmed that it has excellent low dielectric properties of 0.015 or less.

[0201] In contrast, Comparative Preparation Examples 1 and 2, which used less styrene-based and / or vinyl-based compounds during oligomer synthesis, had a problem of having relatively lower heat resistance compared to Preparation Examples 1 to 5.

[0202] In addition, in the case of Comparative Example 3, which used the oligomer of Comparative Example 3 that did not use a vinyl compound during oligomer synthesis, the heat resistance was good, but the dielectric properties were relatively somewhat inferior.

[0203] In addition, Comparative Example 4, in which the oligomer of Comparative Example 4, which did not use a styrene-based compound during oligomer synthesis, was used as a heat resistance enhancer, showed that the varnish did not dissolve well in the solvent, precipitates were formed, and the heat resistance was significantly reduced.

[0204] In addition, the varnishes of Comparative Examples 5 and 6, which used commercially available existing bismaleimides BMI-2300 or BMI-70 as heat resistance enhancers, had problems such as not dissolving well in solvents and precipitation, and Comparative Examples 7 and 8 did not have precipitation in solvents, but compared to other examples and comparative examples, they had very poor heat resistance and showed results with poor dielectric properties.

[0206] Through the above examples and experimental examples, it was confirmed that the present invention can be used as a heat resistance enhancer for epoxy curable resins used in the manufacture of products such as printed circuit boards (CCL, Copper clad laminate), sealants for electronic components, and adhesives, which require low dielectric strength and high heat resistance.

Claims

Claim 1 A heat resistance enhancer for epoxy-based varnish having a bismaleimide structure and excellent solvent solubility and dielectric performance, characterized by comprising an oligomer represented by the following chemical formula 1; [Chemical Formula 1] In Chemical Formula 1, R 1 is a hydrogen atom or a methyl group, and R 2 is C1~C 12 straight-chain alkyl groups or C3~C 12 It is a branched alkyl group, and A is , or and, n is 0 ~ 3, and X is is, R 3 is an aromatic ring compound without carbon atoms or substituents, and R 4 and R 5 Each is independently a hydrogen atom or a methyl group, and R 6 and R 9 Each is independently a hydrogen atom, a methyl group, or an ethyl group, and * indicates a bonding site. Claim 2 In claim 1, A of chemical formula 1 is A heat resistance enhancer for epoxy-based varnish having a bismaleimide structure and excellent solvent solubility and dielectric performance, characterized in that n is 0 to 3. Claim 3 A heat resistance enhancer for epoxy-based varnish having a bismaleimide structure, characterized by having a weight-average molecular weight of 800 to 2,000 and a curing time of 80 to 500 seconds, having excellent solvent solubility and dielectric performance. Claim 4 In claim 1, A of chemical formula 1 is or is, and X is and R 3 is a carbon atom, and R 4 and R 5 is a methyl group, and R 6 and R 9 A heat resistance enhancer for epoxy varnish, characterized in that each is independently a hydrogen atom or a methyl group. Claim 5 A heat resistance enhancer for epoxy-based varnish having a bismaleimide structure, characterized by having a weight-average molecular weight of 1,000 to 2,600 and a curing time of 100 to 550 seconds, having excellent solvent solubility and dielectric performance. Claim 6 In any one of claims 1 to 5, the solubility satisfies 100% or more when the solubility is measured by Formula 1 using a method of measuring the amount of solvent added (g) that generates a precipitate when a solvent is added and stirred at 25°C after preparing a solution by completely dissolving 2.5g of the heat resistance enhancer in 2.5g of DMF (Dimethylformamide), and the solvent comprises: a ketone-based solvent comprising one or more selected from DMAc (Dimethylacetamide), DMF (Dimethylformamide), MEK (methylethyl ketone), MIBK (methyl isobutyl ketone), acetone, and cyclohexanone; an acetate-based solvent comprising one or more selected from PGMEA (Propylene glycol methyl ether acetate) and ethyl acetate; and xylene; A heat resistance enhancer for epoxy-based varnish having a bismaleimide structure and excellent solvent solubility and dielectric performance, characterized by including one or more selected from the above. [Equation 1] Solubility (%) = {Amount of solvent added (g) / Weight of heat resistance enhancer (g)} × 100% Claim 7 A method for manufacturing a heat resistance enhancer for epoxy-based varnish having a bismaleimide structure and excellent solvent solubility and dielectric performance, characterized by performing a process comprising: Step 1, heating a mixed solution in which a maleimide compound represented by Chemical Formula 2 or Chemical Formula 3 and a styrene-based compound represented by Chemical Formula 4 are mixed in a solvent while stirring; Step 2, adding a reaction catalyst to the heated solution and performing heating and a primary main reaction; Step 3, after the completion of the primary main reaction, adding a vinyl-based compound represented by Chemical Formula 5 and a reaction catalyst, and then performing a secondary main reaction; and Step 4, after the completion of the secondary main reaction, cooling to 15 to 30°C to obtain an oligomer represented by Chemical Formula 1 containing a solvent; [Chemical Formula 2] In Chemical Formula 2, n is 0 to 3, and [Chemical Formula 3] In Chemical Formula 3, X is is, R 3 is an aromatic ring compound without carbon atoms or substituents, and R 4 and R 5 Each is independently a hydrogen atom or a methyl group, and R 6 and R 9 Each is independently a hydrogen atom, a methyl group, or an ethyl group, [Chemical Formula 4] R of Chemical Formula 4 1 It is a hydrogen atom or a methyl group, [Chemical Formula 5] R of chemical formula 5 2 is C1~C 12 straight-chain alkyl groups or C3~C 12 It is a branched alkyl group, [Chemical Formula 1] In Chemical Formula 1, R 1 is a hydrogen atom or a methyl group, and R 2 is C1~C 12 straight-chain alkyl groups or C3~C 12 It is a branched alkyl group, and A is , or and, n is 0 ~ 3, and X is is, R 3 is an aromatic ring compound without carbon atoms or substituents, and R 4 and R 5 Each is independently a hydrogen atom or a methyl group, and R 6 and R 9 Each is independently a hydrogen atom, a methyl group, or an ethyl group, and * indicates a bonding site. Claim 8 A method for manufacturing a heat resistance enhancer for epoxy-based varnish having a bismaleimide structure, having excellent solvent solubility and dielectric performance, characterized in that, in claim 7, the heating temperature of the first stage is 35 to 50℃, and the primary main reaction temperature of the second stage and the secondary main reaction temperature of the third stage are 90 to 120℃. Claim 9 A method for manufacturing a heat resistance enhancer for epoxy-based varnish having a bismaleimide structure and excellent solvent solubility and dielectric performance, characterized in that, in claim 7, the mixed solution of the first step comprises 100 to 140 parts by weight of the styrene-based compound and 180 to 250 parts by weight of the solvent per 100 parts by weight of the maleimide compound. Claim 10 A method for manufacturing a heat resistance enhancer for epoxy-based varnish having a bismaleimide structure and excellent solvent solubility and dielectric performance, characterized in that, in claim 7, the amount of the vinyl-based compound in the third stage is 40 to 200 parts by weight per 100 parts by weight of the maleimide compound in the first stage. Claim 11 A prepreg comprising a cured product of a varnish comprising an epoxy resin, the heat resistance enhancer of claim 6, a curing agent, a curing accelerator, and a solvent. Claim 12 A prepreg according to claim 11, wherein the solvent comprises one or more selected from DMAc (Dimethylacetamide), DMF (Dimethylformaimide), MEK (methylethyl ketone), MIBK (methyl isobutyl ketone), acetone, and cyclohexanone; one or more selected from PGMEA (Propylene glycol methyl ether acetate) and ethyl acetate; and one or more selected from xylene. Claim 13 In claim 11, when measuring the glass transition temperature (Tg) using a dynamic mechanical analyzer (DMA) at a measurement frequency of 1 GHz and a measurement temperature of 25°C to 27°C, and when measuring the dielectric constant and dielectric loss of the cured material having a thickness of 0.8 to 1 mm using an impedance analyzer (Agilent E4991B), the dielectric constant (D k ) is 3.50 or less, and dielectric loss (D f A prepreg characterized by ) being 0.015 or less.

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