Tetrazole Compounds, Their Preparation Methods and Applications

Abstract

The present invention relates to a tetrazole compound, a preparation method thereof and an application thereof. The tetrazole compound has a structure shown in formula (I), and can be used as a novel bonding agent for firmly bonding copper / copper alloy and resin, reducing the skin effect, having a good signal transmission effect, and meeting the requirements of high-frequency and high-speed communication products.

Description

Technical Field

[0001] The present invention relates to the field of metal surface treatment, and particularly to a tetrazole compound, a preparation method thereof and an application thereof. Background Art

[0002] In the processing technology of traditional multi-layer printed circuit boards (Printed circuit board, abbreviated as PCB), at present, brownification treatment is mainly used to improve the bonding force between the copper surface and the resin. Brownification is a copper surface micro-etching treatment process based on sulfuric acid / hydrogen peroxide. After the copper surface is brownified, a uniform honeycomb structure will be formed, which can improve the surface roughness of the copper, increase the contact area between the copper surface and the resin and the physical anchoring effect, thereby improving the bonding force between the two.

[0003] In the field of high-frequency and high-speed PCB manufacturing, due to the more stringent requirements for signal integrity of high-frequency and high-speed signals, and at the same time due to the influence of the skin effect, traditional high-roughness brownification can no longer meet the requirements of high-frequency and high-speed signal transmission loss. Therefore, in the processing technology of PCB multi-layer boards, the surface treatment of the copper surface gradually develops towards the direction of low roughness. The reduction of the copper surface roughness will weaken the physical anchoring effect between the copper surface and the resin, resulting in a sharp drop in the bonding force, and even reliability risks. Therefore, enhancing the bonding force between the copper surface and the resin under low roughness conditions has become an important research topic.

[0004] Currently, the reported bonding agent compounds are mainly silane compounds. One end of the molecule has a heterocyclic structure, which can undergo a coordination reaction with the copper surface, and the other end has a silane graft-modified group. The silane hydrolyzes to generate silanol groups. During the lamination process, on the one hand, the silanol groups can undergo self-polymerization to form a cross-linked structure, and on the other hand, they can chemically react with the resin, thereby improving the bonding strength between the copper surface and the resin; the bonding force is improved after the copper surface is bonded with the above silane, but the silane has poor solubility and requires a large amount of solvent during use. In addition, the silanol groups themselves will undergo self-polymerization, resulting in poor stability and very difficult control, leading to adhesion failure. In addition, the silane coupling agent has poor heat resistance, which is mainly manifested in the delamination phenomenon that occurs when the bonding between the copper surface and the resin deteriorates after high-temperature reflow soldering or tin dipping. Summary of the Invention

[0005] The purpose of the present invention is to provide a novel type of tetrazole compound, which can be used as a novel type of bonding agent to firmly bond copper / copper alloy and resin, reduce the skin effect, have good signal transmission effects, and meet the requirements of high-frequency and high-speed communication products.

[0006] The technical solution is as follows:

[0007] A tetrazole compound has a structure shown in formula (I):

[0008]

[0009] Wherein:

[0010] R1 is independently selected from: C2-C6 alkyl, C1-C6 alkoxy, C1-C6 alkylthio, or

[0011] Each R is independently selected from: C1-C6 alkyl, C1-C6 alkoxy, acetamido or halogen;

[0012] m is 1, 2 or 3;

[0013] X is selected from

[0014] R2 is selected from substituted or unsubstituted C1-C20 alkylene or

[0015] A is substituted or unsubstituted C2-C20 alkylene, and n is an integer greater than 0;

[0016] * represents the connection site.

[0017] In one embodiment, the R1 is independently selected from: C2-C6 alkyl, C1-C6 alkoxy, or

[0018] Each R is independently selected from C1-C6 alkyl, C1-C6 alkoxy, acetamido.

[0019] In one embodiment, m is 1.

[0020] In one embodiment, the R2 is selected from unsubstituted C1-C10 alkylene or

[0021] A is unsubstituted C2-C10 alkylene, and n is any integer from 1 to 10.

[0022] In one embodiment, the R2 is selected from unsubstituted C1-C6 straight-chain alkylene, C3-C6 branched-chain alkylene, or

[0023] A is unsubstituted C2-C10 straight-chain alkylene, unsubstituted C3-C10 branched-chain alkylene, and n is any integer from 1 to 10.

[0024] In one embodiment, the tetrazole compound has any of the following structures:

[0025]

[0026]

[0027]

[0028]

[0029] The present invention also provides a method for preparing a tetrazole compound, comprising the following steps:

[0030]

[0031] Mix an epoxide, a compound represented by formula (II) and a base, and react to prepare a tetrazole compound represented by formula (I);

[0032] The epoxide is

[0033] R1 is independently selected from: C2-C6 alkyl, C1-C6 alkoxy, C1-C6 alkylthio, or

[0034] Each R is independently selected from: C1-C6 alkyl, C1-C6 alkoxy, acetylaminophenyl or halogen;

[0035] m is 1, 2 or 3;

[0036] X is selected from

[0037] R2 is selected from substituted or unsubstituted C1-C20 alkylene or

[0038] A is substituted or unsubstituted C2-C20 alkylene, and n is an integer greater than 0;

[0039] * represents the connection site.

[0040] In one embodiment, the molar ratio of the epoxide to the compound represented by formula (II) is 1:(2-2.5).

[0041] In one embodiment, the base is one or more of sodium methoxide, sodium hydroxide, potassium carbonate and triethylamine.

[0042] In one embodiment, the reaction temperature is 50°C to 80°C.

[0043] In one embodiment, the compound represented by formula (II) is selected from: 1-ethyl-5-mercapto-1H-tetrazole, 5-mercapto-1-(4-methoxyphenyl)-1H-tetrazole, 1-(4-ethoxyphenyl)-5-mercapto-1H-tetrazole or 1-(3-acetylaminophenyl)-5-mercaptotetrazole.

[0044] In one embodiment, the epoxide compound is selected from: epichlorohydrin, 1,2,7,8-diepoxyoctane, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether or dipropylene glycol diglycidyl ether.

[0045] The present invention also provides a bonding agent, which comprises the tetrazole compound as described above, or a tetrazole compound prepared by the preparation method of the tetrazole compound as described above.

[0046] The present invention also provides a metal surface treatment liquid, which comprises the bonding agent as described above.

[0047] The present invention also provides an application of the metal surface treatment liquid as described above in the preparation of printed circuit boards.

[0048] The present invention has the following beneficial effects:

[0049] The tetrazole compound provided by the present invention has a molecular structure of a double nitrogen-containing heterocyclic disulfide compound. Instead of using traditional silane compounds for molecular grafting, it is modified with specific functional groups at specific positions. Using this novel compound as a bonding agent can connect metal and resin through chemical bond action, so it can be used for firmly bonding metal and resin, such as bonding copper / copper alloy and resin (such as epoxy resin, polyphenylene ether resin, and hydrocarbon resin, etc.). Moreover, this bonding agent can still have sufficient adhesion to the resin while maintaining a low roughness on the copper surface, and reduce the skin effect, having a good signal transmission effect. In addition, compared with the existing silane compounds, the tetrazole compound provided by the present invention has better solubility, better stability, a wider range of applicable materials and high temperature resistance, ensuring that the performance of the subsequent prepared bonding materials and electronic components meets the requirements of high-frequency and high-speed communication products. Description of the Drawings

[0050] Figure 1 is the SEM image (low roughness) of the copper surface treated with the surface treatment liquid of the bonding agent shown in Example 14;

[0051] Figure 2 The SEM image (high roughness) of the copper surface treated with the treatment liquid of Comparative Experiment 1. Detailed Description of the Embodiments

[0052] The following further describes the present invention in detail with specific embodiments and drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosed content of the present invention more thorough and comprehensive.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0054] In the present invention, "substituted" means that a hydrogen atom in a substituent is replaced by a substituent.

[0055] In the present invention, when the same substituent appears multiple times, it can be independently selected from different groups. For example, if the general formula contains multiple R1s, then R1s can be independently selected from different groups. The six R1s on the benzene ring can be the same as or different from each other.

[0056] In the present invention, "substituted or unsubstituted" means that the defined group can be substituted by R5 or not, and R5 is selected from: C1-20 alkyl, heterocyclic group containing 3-20 ring atoms, C1-20 alkoxy, halogen (F, Cl, Br or I), heteroaryl containing 5-30 ring atoms, heteroaryl containing 6-30 ring atoms.

[0057] In the present invention, "number of ring atoms" means the number of atoms among the atoms constituting the ring itself of a structural compound formed by bonding atoms in a ring (for example, monocyclic compound, fused ring compound, crosslinked compound, carbocyclic compound, heterocyclic compound). When the ring is substituted by a substituent, the atoms contained in the substituent are not included in the ring-forming atoms. The same applies to the "number of ring atoms" described below under the condition of no special explanation. For example, the number of ring atoms of a benzene ring is 6, the number of ring atoms of a naphthalene ring is 10, and the number of ring atoms of a thiophenyl group is 5.

[0058] In the present invention, "alkyl" may represent linear, branched, and / or cyclic alkyl. The number of carbon atoms in the alkyl may be 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Phrases containing this term, for example, "C1-9 alkyl" refers to an alkyl containing 1 to 9 carbon atoms, and each occurrence may independently be C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, C8 alkyl, or C9 alkyl. Non-limiting examples of alkyl include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, cyclopentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl, cyclohexyl, 4-methylcyclohexyl, 4-tert-butylcyclohexyl, n-heptyl, 1-methylheptyl, 2,2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl, n-octyl, tert-octyl, 2-ethyloctyl, 2-butyl octyl, 2-hexyloctyl, 3,7-dimethyloctyl, cyclooctyl, n-nonyl, n-decyl, adamantyl, 2-ethyldecyl, 2-butyldecyl, 2-hexyldecyl, 2-octyldecyl, n-undecyl, n-dodecyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, 2-ethylhexadecyl, 2-butyldecyl, 2-hexyldecyl, 2-octyldecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, 2-ethyleicosyl, 2-butyleicosyl, 2-hexyleicosyl, 2-octyleicosyl, n-heneicosyl, n-docosyl, n-tricosyl, n-tetracosyl, n-pentacosyl, n-hexacosyl, n-heptacosyl, n-octacosyl, n-nonacosyl, n-triacontyl, adamantane, etc. "Alkylene" is an alkyl that has further lost one hydrogen atom, such as methylene, ethylene, propylene, or ethylene substituted with a methyl group.

[0059] "Aryl, aromatic group or aromatic radical" refers to a hydrocarbon group containing at least one aromatic ring. "Heteroaromatic group or heteroaromatic radical" refers to an aromatic hydrocarbon group containing at least one heteroatom. The heteroatom is preferably selected from N, O, S. A fused-ring aromatic group means that the rings of the aromatic group can have two or more rings, where two carbon atoms are shared by two adjacent rings, that is, a fused ring. A fused hetero-ring aromatic group means a fused-ring aromatic hydrocarbon group containing at least one heteroatom. For the purposes of the present invention, an aromatic group or heteroaromatic group includes not only the system of aromatic rings, but also non-aromatic ring systems. Thus, systems such as pyridine, thiophene, pyrrole, pyrazole, triazole, imidazole, oxazole, oxadiazole, thiazole, tetrazole, pyrazine, pyridazine, pyrimidine, triazine, carbene, etc. are also considered aromatic groups or hetero-ring aromatic groups for the purposes of this invention. For the purposes of the present invention, a fused-ring aromatic or fused hetero-ring aromatic ring system includes not only the system of aromatic groups or heteroaromatic groups, but also, where multiple aromatic groups or hetero-ring aromatic groups can also be interrupted by short non-aromatic units (<10% non-H atoms, preferably less than 5% non-H atoms, such as C, N or O atoms). Thus, systems such as 9,9'-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ether, etc. are also considered fused-ring aromatic ring systems for the purposes of this invention.

[0060] In a preferred embodiment, the aromatic group is selected from: benzene, naphthalene, anthracene, fluoranthene, phenanthrene, benzophenanthrene, dibenzo[a,h]anthracene, tetracene, pyrene, benzopyrene, acenaphthene, fluorene, and their derivatives; the heteroaromatic group is selected from triazine, pyridine, pyrimidine, imidazole, furan, thiophene, benzofuran, benzothiophene, indole, carbazole, pyrroloimidazole, pyrrolopyrrole, thiophenopyrrole, thiophenothiophene, furanopyrrole, furanofuran, thiophenofuran, benzisoxazole, benzisothiazole, benzimidazole, quinoline, isoquinoline, phthalazine, quinoxaline, phenanthridine, perimidine, quinazoline, quinazolinone, dibenzothiophene, dibenzofuran, carbazole and their derivatives.

[0061] "Amino" refers to a derivative of an amine, having the structural feature of the formula -N(X)2, where each "X" is independently H, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted heterocyclic group, etc. Non-limiting types of amino groups include -NH2, -N(alkyl)2, -NH(alkyl), -N(cycloalkyl)2, -NH(cycloalkyl), -N(heterocyclic group)2, -NH(heterocyclic group), -N(aryl)2, -NH(aryl), -N(alkyl)(aryl), -N(alkyl)(heterocyclic group), -N(cycloalkyl)(heterocyclic group), -N(aryl)(heteroaryl), -N(alkyl)(heteroaryl), etc.

[0062] In the present invention, "*" connected to a single bond represents the connection site.

[0063] In the present invention, when the connection site is not specified in the group, it means that any optional connection site in the group can be used as the connection site.

[0064] In the present invention, the single bond to which the substituent is attached passes through the corresponding ring, indicating that the substituent can be connected to any optional position of the ring. For example in which R is connected to any substitutable site of the benzene ring.

[0065] The present invention provides a novel class of tetrazole compounds, which can be used as a bonding agent for firmly bonding copper / copper alloy and resin.

[0066] The technical solution is as follows:

[0067] A tetrazole compound having a structure as shown in formula (I):

[0068]

[0069] Wherein:

[0070] R1 is independently selected from: C2-C6 alkyl, C1-C6 alkoxy, C1-C6 alkylthio, or

[0071] Each R is independently selected from: C1-C6 alkyl, C1-C6 alkoxy, acetamido or halogen;

[0072] m is 1, 2 or 3;

[0073] X is selected from

[0074] R2 is selected from substituted or unsubstituted C1-C20 alkylene or

[0075] A is substituted or unsubstituted C2-C20 alkylene, and n is an integer greater than 0;

[0076] * represents the connection site.

[0077] In one embodiment, the R1 is independently selected from: C2-C6 alkyl, C1-C6 alkoxy, or

[0078] Each R is independently selected from C1-C6 alkyl, C1-C6 alkoxy, acetamido.

[0079] In one embodiment, m is 1.

[0080] In one embodiment, the R1 is selected from: methoxy, ethoxy or acetamido.

[0081] In one embodiment, the R2 is selected from unsubstituted C1-C10 alkylene or

[0082] A is an unsubstituted C2-C10 alkylene group, and n is any integer from 1 to 10 (1, 2, 3, 4, 5, 6, 7, 8, 9, or 10).

[0083] In one embodiment, R2 is selected from an unsubstituted C1-C6 straight-chain alkylene group, a C3-C6 branched-chain alkylene group, or

[0084] A is an unsubstituted C2-C10 straight-chain alkylene group or an unsubstituted C3-C10 branched-chain alkylene group, and n is any integer from 1 to 10.

[0085] In one embodiment, R2 is selected from: -CH2CH2-, -CH2CH2CH2CH2-,

[0086]

[0087] In one embodiment, the tetrazole compound has any of the following structures:

[0088]

[0089]

[0090]

[0091]

[0092] The present invention also provides a method for preparing a tetrazole compound, comprising the following steps:

[0093]

[0094] Mix an epoxide, a compound represented by formula (II) with a base, and react to prepare a tetrazole compound represented by formula (I);

[0095] The epoxide is

[0096] R1 is independently selected from: a C2-C6 alkyl group, a C1-C6 alkoxy group, a C1-C6 alkylthio group, or

[0097] Each R is independently selected from: a C1-C6 alkyl group, a C1-C6 alkoxy group, an acetamidophenyl group, or a halogen;

[0098] m is 1, 2, or 3;

[0099] X is selected from

[0100]

[0101] A is a substituted or unsubstituted C2-C20 alkylene group, and n is an integer greater than 0;

[0102] * represents the connection site.

[0103] In one embodiment, the molar ratio of the epoxide to the compound represented by formula (II) is 1:(2-2.5).

[0104] In one embodiment, the base is one or more of sodium methoxide, sodium hydroxide, potassium carbonate, and triethylamine.

[0105] In one embodiment, the reaction temperature is 50°C to 80°C.

[0106] In one embodiment, the compound represented by formula (II) is selected from: 1-ethyl-5-mercapto-1H-tetrazole, 5-mercapto-1-(4-methoxyphenyl)-1H-tetrazole, 1-(4-ethoxyphenyl)-5-mercapto-1H-tetrazole, or 1-(3-acetamidophenyl)-5-mercaptotetrazole.

[0107] In one embodiment, the epoxide is selected from: epichlorohydrin, 1,2,7,8-diepoxyoctane, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, or dipropylene glycol diglycidyl ether.

[0108] The present invention also provides a bonding agent, which comprises the tetrazole compound as described above, or a tetrazole compound prepared by the preparation method of the tetrazole compound as described above.

[0109] The present invention also provides a metal surface treatment solution, which comprises the bonding agent as described above.

[0110] In one comparative example, the metal surface treatment solution comprises water and the bonding agent as described above.

[0111] In one comparative example, the metal surface treatment solution comprises water and the following components:

[0112]

[0113] The surface treatment solution of the present invention can be contacted with the copper / copper alloy surface by using currently conventional methods, for example, spraying, dipping and other methods can be adopted.

[0114] The contact time between the surface treatment liquid and copper / copper alloy is not particularly limited. For the purpose of enabling the treatment liquid to act on the surface of copper / copper alloy, it is preferably 10 to 150 s, and more preferably 20 to 90 s.

[0115] The temperature of the treatment liquid when contacting copper / copper alloy is preferably 20°C to 60°C, and more preferably 30°C to 40°C.

[0116] After the treatment liquid contacts copper / copper alloy, it can be left standing at room temperature, or directly dried with cold air or hot air, or dried at 50°C to 120°C.

[0117] By using the surface treatment liquid of the present invention to treat the surface of copper / copper alloy, an organic molecular film can be formed on the surface of copper / copper alloy. Through the strong chemical bond action between copper-organic film-resin, the adhesion between the copper surface and the resin material can be improved. After using the dinitrogen heterocyclic disulfide compound of the present invention as a bonding agent for the adhesive material, even in the case of low surface roughness, the adhesion between copper / copper alloy and resin can be ensured and it has good heat resistance. It can be applied to the manufacture of PCBs, such as the manufacture of multi-layer laminates, and can also be used for the preparation of semiconductor components, and can also be used for electronic components in 5G high-frequency communications, such as the bonding or metallization of dielectric ceramics, etc.

[0118] Preferably, the present invention also provides the application of the above-mentioned metal surface treatment liquid in the preparation of printed circuit boards.

[0119] In the following specific embodiments, unless otherwise specified, all are conventional methods; the raw materials, reagent materials, etc. used in the following specific embodiments, unless otherwise specified, are all commercially available products.

[0120] Example 1

[0121] This example provides 1,13-bis((1-(3-acetamidophenyl)-tetrazol-5-yl)thio)-4,7,10-trioxa-tridecane-2,12-diol and its preparation method, which are as follows:

[0122] Dissolve 1-(3-acetamidophenyl)-5-mercapto-tetrazole (11.77 g, 50 mmol) in N,N-dimethylformamide (50 mL), add sodium methoxide (2.71 g, 50 mmol), stir at room temperature for 30 min, and then add diethylene glycol diglycidyl ether (5.46 g, 25 mmol), and heat to 70°C for reaction for 15 hours. After the reaction is completed, cool to room temperature, filter off the insoluble matter, and then carry out vacuum concentration to obtain a light yellow oil (15.67 g, calculated based on the molar number of diethylene glycol diglycidyl ether, yield 91%).

[0123] The 1H NMR data of the obtained oily substance are as follows:

[0124] 1 H NMR(300MHz,CDCl3)δ:7.85 - 7.36(m,8H), 3.86(m,2H), 3.7(m,4H), 3.55(t,8H), 3.14(d,4H), 2.08(s,6H).

[0125] Based on the above spectral data, the obtained oily substance was identified as the compound shown by the following chemical formula:

[0126]

[0127] Example 2

[0128] This example provides 1,12 - bis((1 - (3 - acetamidophenyl) - tetrazol - 5 - yl)thio) - 4,9 - dioxadodecane - 2,11 - diol and its preparation method, which are as follows:

[0129] Dissolve 1 - (3 - acetamidophenyl) - 5 - mercaptotetrazole (11.77 g, 50 mmol) in N,N - dimethylformamide (50 mL), add sodium methoxide (2.71 g, 50 mmol), stir at room temperature for 30 min, and then add 1,4 - butanediol diglycidyl ether (5.06 g, 25 mmol), and heat to 70 °C for reaction for 15 hours. After the reaction is completed, cool to room temperature, filter off the insoluble matter, and then carry out vacuum concentration to obtain a light yellow oily substance (15.65 g, calculated based on the molar amount of 1,4 - butanediol diglycidyl ether, with a yield of 93%).

[0130] The 1H NMR of the obtained oily substance is as follows:

[0131] 1 H NMR(300MHz,CDCl3)δ:7.85 - 7.36(m,8H), 3.86(m,2H), 3.7(m,4H), 3.43(m,4H), 3.14(d,4H), 2.08(s,6H), 1.55(m,4H).

[0132] Based on the above spectral data, the obtained oily substance was identified as the compound shown by the following chemical formula:

[0133]

[0134] Example 3

[0135] This example provides 1,13-bis((1-(4-ethoxyphenyl)-tetrazol-5-yl)thio)-4,7,10-trioxa-tridecane-2,12-diol and its preparation method, which are as follows:

[0136] Dissolve 1-(4-ethoxyphenyl)-5-mercapto-1H-tetrazole (11.12 g, 50 mmol) in methanol (50 mL), add sodium methoxide (2.71 g, 50 mmol), stir at room temperature for 30 min, and then add diethylene glycol diglycidyl ether (5.46 g, 25 mmol), and heat to 60 °C for reaction for 18 hours. After the reaction is completed, cool to room temperature, filter off the insoluble matter, and then carry out concentration under reduced pressure to obtain a light yellow oil (15.25 g, calculated based on the molar amount of diethylene glycol diglycidyl ether, yield 92%).

[0137] The 1H NMR data of the obtained oil are as follows:

[0138] 1 H NMR (300 MHz, CDCl3) δ: 7.55 - 7.03 (m, 8H), 4.15 (m, 4H), 3.86 (m, 2H), 3.7 (m, 4H), 3.55 (t, 8H), 3.14 (d, 4H), 1.36 (t, 6H).

[0139] Based on the above spectral data, the obtained oil was identified as the compound shown by the following chemical formula:

[0140]

[0141] Preparation of tetrazole compounds in Examples 4 - 21

[0142] According to the above compound preparation method and the reactants and molar ratios shown in Table 1, the compounds in Examples 4 - 21 were respectively prepared.

[0143] Table 1

[0144]

[0145]

[0146]

[0147]

[0148] Comparative Example 1

[0149] Prepare the existing nitrogen-containing heterocyclic silane compound: 2-methylthio-5-[3-(trimethoxysilyl)propylthio]-1,3,4-thiadiazole

[0150] Dissolve 2-mercapto-5-methylthio-1,3,4-thiadiazole (8.22 g, 50 mmol) in dry N,N-dimethylformamide (50 mL), add sodium methoxide (2.70 g, 50 mmol), stir at room temperature for 30 min, then add 3-chloropropyltrimethoxysilane (9.94 g, 50 mmol), and react at 70 °C for 18 h. After the reaction is completed, cool to room temperature, filter off the insoluble matter, and then carry out concentration under reduced pressure to obtain a light yellow oil (14.05 g, 43 mmol, yield 86%).

[0151] The 1H NMR data of the obtained oil are as follows:

[0152] 1 H NMR (300 MHz, CDCl3) δ: 3.57 (s, 9H), 3.30 (t, 2H), 2.76 (s, 3H), 1.91 (quint, 2H), 0.80 (t, 2H).

[0153] Based on the above spectral data, the obtained oil was identified as the azidosilane compound shown by the following chemical formula:

[0154]

[0155] Comparative Example 2

[0156] Prepare the existing nitrogen-containing heterocyclic silane compound: 2-[3-(trimethoxysilyl)propylthio]-benzimidazole

[0157] Dissolve 2-mercaptobenzimidazole (7.51 g, 50 mmol) in dry methanol (50 mL), add sodium methoxide (2.70 g, 50 mmol), stir at room temperature for 30 min, then add 3-chloropropyltrimethoxysilane (9.94 g, 50 mmol), and react at 60 °C for 24 h. After the reaction is completed, cool to room temperature, filter off the insoluble matter, and then carry out concentration under reduced pressure to obtain a brownish yellow oil (13.75 g, 44 mmol, yield 88%).

[0158] The 1H NMR data of the obtained oil are as follows:

[0159] 1 H NMR (300 MHz, CDCl3) δ: 7.78 (m, 2H), 7.42 (m, 2H), 3.59 (s, 9H), 3.14 (t, 2H), 1.85 (m, 2H), 0.80 (t, 2H).

[0160] Based on the above spectral data, the obtained oil was identified as the azidosilane compound shown by the chemical formula:

[0161]

[0162] Application effect test

[0163] (1) Preparation of surface treatment solution:

[0164] The tetrazole compound bonders of Examples 1 to 4, Example 14, and Example 16 and the nitrogen-containing heterocyclic silane compounds prepared in Comparative Examples 1 to 2 were respectively formulated into 1 g / L aqueous solutions to obtain surface treatment solutions (1) to (8) containing bonders, and they were reserved for use.

[0165] (2) Treatment process:

[0166] 1) Pickling: Remove the copper surface oxide with a sulfuric acid solution (sulfuric acid mass content is 3%), and treat at room temperature (25°C ± 1°C) for 20 s to 30 s;

[0167] 2) Water washing: Wash with deionized water for 10 s to 20 s;

[0168] 3) Alkaline washing: Remove organic pollutants such as grease on the copper surface, and treat at 45°C for 40 s to 60 s;

[0169] 4) Water washing: Wash with deionized water for 10 s to 20 s;

[0170] 5) Activation: Activate the copper surface, which is beneficial to the subsequent reaction between the copper surface and the bonder, at 30°C to 35°C, and the treatment time is 40 s to 60 s;

[0171] 6) Water washing: Wash with deionized water for 10 s to 20 s;

[0172] 7) Treatment with surface treatment solutions (1) to (8): Form an organic bonding film on the copper surface, and crosslink with the resin during the high-temperature curing process, thereby enhancing the bonding force between the copper surface and the resin. The treatment temperature is 30°C to 35°C, and the treatment time is 30 s to 60 s;

[0173] 8) Water washing: Wash with deionized water for 10 s to 20 s;

[0174] 9) Drying: The drying temperature is 85°C, and the drying time is 60 s.

[0175] After the copper surface is processed through the above process and treatment, a low-roughness surface is formed. Among them, the electron microscope image of the copper surface treated with the surface treatment solution containing the bonder shown in Example 14 is shown in the appendix Figure 1 .

[0176] In addition, to highlight the comparison effect of the bonding force between the copper surface and the resin, an additional comparative experiment was added. This comparative group is the traditional treatment method for improving the bonding force between the copper surface and the resin. After micro-etching treatment, a high-roughness copper surface is formed (the electron microscope image is shown in the appendix Figure 2) The specific treatment solutions used in this comparative experiment are as follows:

[0177]

[0178] The rest is water.

[0179] The copper-clad laminate that has been pickled, alkali-washed, and activated is then treated with the above-mentioned comparative experiment treatment solution, washed with water, dried, and laminated with resin and cured to make a test board.

[0180] (3) Adhesion and heat resistance evaluation tests

[0181] The adhesion and heat resistance are measured according to the standards "IPC-TM-650 No.2.4.8" and "IPC-TM-650 No.2.6.8" respectively.

[0182] The obtained results are shown in Table 2:

[0183] Table 2

[0184]

[0185]

[0186] The above results show that:

[0187] In Comparative Experiment 1, traditional micro-etching treatment is used, the copper surface roughness is relatively high (Rz > 2.0μm, specific surface area Sdr > 1.4), the physical bonding force between the copper surface and the resin reaches 2.93 lb / in, and the number of times of resistance to reflow soldering exceeds 15 times; in Comparative Experiment 2, low-roughness micro-etching treatment is carried out on the copper surface, the copper surface roughness is low (Rz < 1.5μm, specific surface area Sdr < 1.2), no bonding treatment is carried out, the adhesion between the copper surface and the resin is lower than 1.0 lb / in, and the thermal reliability is poor.

[0188] For Comparative Examples 1 to 2, 3-chloropropyltrimethoxysilane grafted modified nitrogen-containing heterocyclic compounds are used. The prepared nitrogen-containing heterocyclic silane compounds still have the properties of silane functional groups. The silanol groups formed after the hydrolysis of the silicon-oxygen bond will undergo self-polymerization reaction. After standing for 30 days, the surface treatment solution becomes turbid, resulting in a decrease in adhesion and reliability. The adhesion of Comparative Examples 1 to 2 did not reach the adhesion of Comparative Experiment 1, and the thermal reliability did not exceed 15 times.

[0189] In Examples 1 to 4, Example 14, and Example 16, the surface treatment liquid of the bonding agent of the present invention was used. After treatment, the bonding force between the copper surface and the resin exceeded that of the comparative examples and the comparative experiments, and the number of times of resistance to reflow soldering was stably more than 15 times. After the surface treatment liquid was placed for 30 days, the surface treatment liquids of Examples 1 to 4, Example 14, and Example 16 maintained a clear state, the bonding force remained basically unchanged, and the thermal reliability remained unchanged, indicating that the bonding agent involved in the present invention and the surface treatment liquid formed thereby are superior in terms of stability, mechanical properties, and thermal reliability.

[0190] Figure 1 It is the SEM image (low roughness) of the copper surface treated with the surface treatment liquid of the bonding agent shown in Example 14; Figure 2 The SEM image (high roughness) of the copper surface treated with the treatment liquid of Comparative Experiment 1. Comparison Figure 1 and Figure 2 It can be seen that by using the novel tetrazole compound provided by the present invention as the bonding agent, it is still possible to have sufficient bonding force with the resin while maintaining a low roughness on the copper surface.

[0191] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0192] The above-described embodiments merely represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A tetrazole compound, characterized in that It has a structure as shown in formula (I): Formula (I) in: R1 are independently selected from: C2~C6 alkyl or ; R is selected from: C1~C6 alkoxy or acetylamino; m is 1; X is ; R2 is selected from unsubstituted C1~C6 straight chain alkylene, C3~C6 branched chain alkylene or ; A is an unsubstituted C2~C10 alkylene group, and n is an integer from 1 to 3; * indicates the attachment site.

2. The tetrazole compound according to claim 1, wherein R2 is selected from: -CH2CH2-, -CH2CH2CH2CH2-, 、 、 or .

3. The tetrazole compound according to claim 1, wherein Has any of the following structures: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 。 4. A method for preparing a tetrazole compound, characterized in that: The steps include: ； An epoxy compound, a compound represented by formula (II) and a base are mixed and reacted to prepare a tetrazole compound represented by formula (I); The epoxy compound is ; R1 are independently selected from: C2~C6 alkyl or ; R is selected from: C1~C6 alkoxy or acetylamino; m is 1; X is ; R2 is selected from unsubstituted C1~C6 straight chain alkylene, C3~C6 branched chain alkylene or ; A is an unsubstituted C2~C10 alkylene group, and n is an integer from 1 to 3; * indicates the attachment site.

5. The method for preparing a tetrazole compound according to claim 4, wherein The molar ratio of the epoxy compound to the compound represented by formula (II) is 1:(2-2.5); and / or The base is one or more of sodium methoxide, sodium hydroxide, potassium carbonate and triethylamine; and / or The reaction temperature is 50°C~80°C.

6. The method for preparing a tetrazole compound according to claim 4 or 5, wherein: The compound represented by formula (II) is selected from: 1-ethyl-5-mercapto-1H-tetrazole, 5-mercapto-1-(4-methoxyphenyl)-1H-tetrazole, 1-(4-ethoxyphenyl)-5-mercapto-1H-tetrazole or 1-(3-acetylaminophenyl)-5-mercaptotetrazole; The epoxy compound is selected from: 1,2,7,8-diepoxyoctane, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether or dipropylene glycol diglycidyl ether.

7. A bonding agent, characterized in that The invention comprises the tetrazole compound according to any one of claims 1 to 3.

8. A metal surface treatment liquid, characterized in that: Contains the bonding agent according to claim 7.

9. Use of the metal surface treatment liquid according to claim 8 in the preparation of printed circuit boards.

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