CN114958169A

CN114958169A - Crosslinking catalyst for preparing graphical metal layer

Info

Publication number: CN114958169A
Application number: CN202210512939.0A
Authority: CN
Inventors: 冯哲圣; 王莉婷; 王焱; 赵永强
Original assignee: Suining Diyin Technology Co ltd; University of Electronic Science and Technology of China
Current assignee: Suining Diyin Technology Co ltd; University of Electronic Science and Technology of China
Priority date: 2022-05-11
Filing date: 2022-05-11
Publication date: 2022-08-30
Anticipated expiration: 2042-05-11
Also published as: CN114958169B

Abstract

A crosslinking catalyst for preparing a graphical metal layer belongs to the technical field of electronics and relates to a preparation technology of the graphical metal layer. Dissolving the solid polyurethane resin in the organic solvent, then adding the organic amine, mixing, stirring, performing acylation reaction, adding the active source, stirring, dispersing, and performing crosslinking reaction to obtain the crosslinking catalyst. The invention combines solid polyurethane resin and specific organic amine (RNH) ₂ ) Mixing, acylating reaction to generate functional carbamido (-NHCONH-), fixing active material and combining with medium base plate. The catalytic activity auxiliary layer is formed on the surface of the substrate by printing or spraying, and the patterned metal layer with ultrahigh adhesion performance can be prepared by further metal ion reduction deposition, and the prepared patterned metal layer is compact and uniform, has high line fineness and can be used for preparing a Printed Circuit Board (PCB)The method is used for preparing various miniature complex conductive patterns; the invention has simple process, low cost, no need of etching, low-temperature short-time preparation and suitability for mass and large-scale production.

Description

Crosslinking catalyst for preparing graphical metal layer

Technical Field

The invention belongs to the technical field of electronics, relates to preparation of a patterned metal layer, and particularly relates to a catalyst used in the preparation process of the patterned metal layer.

Background

The main methods for manufacturing the patterned metal layer on the surface of the dielectric substrate include metal spraying, physical vapor deposition and chemical plating, wherein the metal spraying and physical vapor deposition technologies can prepare the conductive metal layer with better performance, but have higher requirements on experimental conditions and experimental equipment, generate larger energy consumption and are not beneficial to industrial large-scale production, and the chemical plating has the advantages of uniform plating layer, simple process, low cost, strong adaptability to base materials and the like, and is widely applied to the fields of electronic devices, energy automobiles, aerospace and the like.

In order to realize effective adhesion between the dielectric substrate and the conductive metal layer and ensure complete transmission of signals, the dielectric substrate must be modified in advance to improve adhesion performance. At present, the surface roughness of the substrate is usually improved, and a polar group is introduced into the surface of the substrate to improve the bonding strength between the base material and the conductive metal layer, but the former can cause the base material to be too rough while improving the adhesion, thereby causing more serious problems of insertion loss, signal distortion and the like. Therefore, Polymer Assisted Metal Deposition (PAMD) is widely used as an important chemical grafting method on a variety of flexible, rigid, organic and inorganic substrates. The technology is mainly characterized in that a thin polymer functional layer is prepared on the surface of a base material in a chemical grafting mode, and the polymer functional layer can strongly adsorb and activate metal particles through a bonding effect, so that the ultrahigh bonding strength of the base material and a metal layer can be realized.

With the development of consumer electronics toward miniaturization, light weight, and high reliability, the patterned metal layer is used as an important structure for power transmission/distribution among components in an electronic circuit system and electromagnetic signal transmission/reception, and accordingly needs to meet the requirements of ultra-thinning and miniaturization, and therefore, a new challenge is also presented to selective metallization of the surface of the dielectric substrate (i.e., preparation of the patterned metal layer on the surface of the dielectric substrate).

Disclosure of Invention

The invention provides a crosslinking catalyst for preparing a patterned metal layer, which can realize high-adhesion bridging between the metal layer and a medium substrate and can be used as a catalytic activity ion carrier. The crosslinking catalyst provided by the invention is printed or sprayed to form an ultrathin catalytic activity polymer auxiliary layer on the surface of the substrate, and then the conductive metal layer (or the patterned metal layer) with ultrahigh adhesion performance can be prepared by metal ion reduction deposition.

The technical scheme of the invention is realized as follows:

a crosslinking catalyst for preparing a patterned metal layer is characterized by comprising 3-15% of organic amine, 1-5% of an active source, 8-20% of solid polyurethane resin and 60-80% of an organic solvent in percentage by mass;

the organic amine is a compound in which one hydrogen atom in an ammonia molecule is substituted by alkyl; the active source is one or more of soluble silver salt, soluble palladium salt or soluble nickel salt; the organic solvent is one or more of isophorone, dibasic ester or diethylene glycol butyl ether acetate;

dissolving the solid polyurethane resin in the organic solvent, then adding the organic amine, mixing, stirring, performing acylation reaction, adding the active source, stirring, dispersing, and performing crosslinking reaction to obtain the crosslinking catalyst.

Further, the number of C atoms in the carbon chain of the organic amine is not more than 8. Specifically, it may be one or more of 2-pentylamine, 3-methyl-2-butylamine, sec-butylamine, and isopropylamine.

In the technical scheme, the viscosity of the crosslinking catalyst is 3000-10000 mPa & S, and the subsequent printing or spraying process can be met.

The invention also provides a preparation method of the graphical metal layer of the cross-linking catalyst, which adopts the following technical scheme:

a preparation method of a patterned metal layer is characterized by comprising the following steps:

step 1: printing a layer of cross-linking catalyst consistent with the target pattern of the graphical metal layer on the surface of the medium substrate; the crosslinking catalyst comprises 3-15% of organic amine, 1-5% of active source, 8-20% of solid polyurethane resin and 60-80% of organic solvent in percentage by mass; dissolving the solid polyurethane resin in the organic solvent, then adding the organic amine, mixing, stirring, performing acylation reaction, adding the active source, stirring, dispersing, and performing crosslinking reaction to obtain the crosslinking catalyst; the organic amine is a compound in which one hydrogen atom in an ammonia molecule is substituted by alkyl; the active source is one or more of soluble silver salt, soluble palladium salt or soluble nickel salt; the organic solvent is one or more of isophorone, dibasic ester or diethylene glycol butyl ether acetate.

Step 2: fixing at constant temperature to fix the graphical cross-linking catalyst printed on the surface of the medium substrate; the constant temperature fixing temperature is 130-160 ℃, and the constant temperature fixing time is 1-5 minutes.

And step 3: and (3) putting the dielectric substrate treated in the steps (1) and (2) into the metal deposition liquid for heating and soaking, performing ion reduction deposition, and drying to obtain the patterned metal layer on the dielectric substrate.

Further, in the crosslinking catalyst used in the step 1, the organic amine is a short-carbon-chain primary amine in which the number of C atoms in a carbon chain is not more than 8. Specifically, it may be one or more of 2-pentylamine, 3-methyl-2-butylamine, sec-butylamine, and isopropylamine.

The means for applying the crosslinking catalyst to the surface of the dielectric substrate may include various printing, spin coating, or printing (including flexographic, gravure, or screen printing) processes. The dielectric substrate comprises a flexible substrate and a rigid substrate, wherein the flexible substrate is a polyethylene terephthalate, polyethylene naphthalate or polyimide substrate, and the rigid substrate is a resin plate, a ceramic substrate or a glass substrate. The metal deposition solution is chemical copper plating solution, chemical nickel plating solution or chemical silver plating solution.

Further, in the step 3, heating and soaking are carried out in the metal deposition liquid at the temperature of 25-50 ℃ for 15-25 minutes.

The crosslinking catalyst for preparing the graphical metal layer creatively utilizes organic amine (RNH2) and polyurethane solid polyurethane resin to generate functional carbamido after acylation. As shown in fig. 1, the functionalized carbamido group is a double-end functional group, one end of the functionalized carbamido group is a polar carbonyl group (-C ═ O) containing a carbon-oxygen double bond, and the functionalized carbamido group can be firmly bonded with the surface of a substrate through a chemical bond; the other end is two imino groups, the N atom contained in the imino groups provides lone pair electrons, and the lone pair electrons and active metal ions which provide empty orbits in the crosslinking catalyst form stable ligands, so that the stable ligands have more catalytic active sites and induce the faster deposition of a metal layer. Printing the crosslinking catalyst on the surface of a substrate to form a precursor active grafting layer (as shown in figure 2), firmly combining the grafting layer with the substrate after constant temperature curing, forming a catalytic active site on the surface of the grafting layer, putting the catalytic active site into metal deposition liquid, carrying out displacement reaction on metal ions and reduced active ions, starting crystallization on the surface of the grafting layer, and finally generating the patterned metal layer with ultrahigh adhesion performance. Therefore, the functional carbamido group generated after the amino acylation of the specific organic amine and the polyurethane monomer realizes the high adhesion bridging of the metal layer and the medium substrate and can be used as a carrier of catalytic active ions.

The invention has the beneficial effects that: (1) according to the invention, the specific organic amine which is easy to perform amino acylation with the polyurethane monomer and then urea group functionalization is used as a crosslinking active ingredient, the dispersion degree is high, the specific surface area is large, more active sites are exposed (as shown in figure 2), higher catalytic activity is shown, only 1-5 wt% of active source ingredient is needed, and the cost of the whole crosslinking catalyst is extremely low; (2) the crosslinking catalyst prepared by the invention contains a large amount of polar groups, so that the precursor active grafting layer has excellent adhesion fastness on the surface of the medium substrate, and the adhesion of a graphical metal layer prepared by the crosslinking catalyst on the medium substrate is greatly improved; (3) the graphical metal layer prepared by the crosslinking catalyst provided by the invention is compact and uniform, has high line fineness, and can be used for preparing various miniature complex conductive patterns or other application scenes needing to prepare precise graphical metal layers on a dielectric substrate, as shown in fig. 3(a), 3(b) and 3 (c); (4) the method for preparing the graphical metal layer belongs to an addition preparation method, and has the advantages of simple process, low cost, no need of etching, capability of realizing low-temperature short-time preparation, suitability for mass large-scale production and the like.

Drawings

Fig. 1 is a schematic diagram of a mechanism for preparing a patterned metal layer according to the present invention.

FIG. 2 is an SEM image of a precursor active graft layer prepared on the surface of a dielectric substrate.

FIG. 3 is an optical photograph of a patterned metal layer prepared on different dielectric substrates according to the proposed technique. (a) The photo is a photo of a patterned metal layer prepared on a glass substrate, (b) is a photo of a patterned metal layer prepared on a flexible substrate (paper base, PI), and (c) is a photo of a patterned metal layer prepared on a ceramic substrate.

Fig. 4 is a photo-optic comparison of the patterned metal layers obtained in example 1 and comparative example, wherein (a) is the patterned metal layer obtained in example 1, and (b) is the patterned metal layer obtained in comparative example.

Detailed Description

Example 1:

step 1: adding 14 wt% of solid polyurethane resin particles into 68 wt% of diluting solvent, heating, stirring and dissolving, stopping stirring and cooling to room temperature after the resin particles are completely dissolved, then adding 15 wt% of specific organic amine, stirring uniformly, adding 3 wt% of active source, and stirring until no granular solid exists, thus obtaining the crosslinking catalyst;

step 2: and (2) preparing a graphical precursor active grafting layer on the medium substrate by printing the crosslinking catalyst prepared in the step (1), then placing the graphical precursor active grafting layer in a thermostat at 160 ℃ for curing for 5min, then placing the graphical precursor active grafting layer in a constant-temperature metal deposition solution at 48 ℃ for graphical deposition for 15min, finally taking out the graphical precursor active grafting layer, washing the graphical precursor active grafting layer by using a large amount of deionized water, and drying the graphical metal layer to obtain a graphical metal layer on the medium substrate.

And step 3: cutting the graphical metal layer into 100 small squares with the size of 1mm multiplied by 1mm by using a hundred-grid cutter, forming uniform latticed ditches on the surface of the metal layer, covering a test area by using a 3M adhesive tape with the number of 250, wiping the test area by using a scraper tool to enable the adhesive tape to be in better contact with the metal layer, and finally tearing the 3M adhesive tape at a uniform speed to finish the test of the adhesive property of the metal layer.

Examples 2-6 the specific procedures were as in example 1, and the specific formulations and constant temperature cure times are shown in Table one:

table one embodiment of the invention

Comparative example:

step 1: adding 14 wt% of solid polyurethane resin particles into 68 wt% of diluting solvent, heating, stirring and dissolving, stopping stirring and cooling to room temperature after the resin particles are completely dissolved, then adding 15 wt% of ammonia water, stirring uniformly, adding 3 wt% of active source, and stirring until no granular solid exists, thus obtaining the catalytic activity ink;

step 2: and (2) preparing a graphical precursor active grafting layer on the medium substrate by printing the catalytic active ink prepared in the step (1), then placing the graphical precursor active grafting layer in a thermostat at 160 ℃ for curing for 5min, then placing the graphical precursor active grafting layer in a constant-temperature metal deposition liquid at 48 ℃ for graphical deposition for 15min, finally taking out the graphical precursor active grafting layer, washing the graphical precursor active grafting layer by using a large amount of deionized water, and drying the graphical precursor active grafting layer to obtain a graphical metal layer on the medium substrate.

The viscosity, cure rate and adhesion to the substrate of the crosslinking catalyst and the adhesion of the metal layer to the substrate are described in table. The adhesion grade is according to ASTM D3359-02 standard, no shedding is 5B, the shedding area is less than 5 percent to 4B, the shedding area is 5-15 percent to 3B, the shedding area is 15-35 percent to 2B, the shedding area is 35-65 percent to 1B, and the shedding area is more than 65 percent to 0B.

TABLE-Di Cross-linking catalyst Performance test

Fig. 4 is optical photographs of the patterned metal layers obtained in example 1 and comparative example, and it can be obtained from fig. 4 that the patterned metal layer prepared in example 1 of the present invention is dense, uniform and excellent in adhesion property; the quality of the patterned metal layer prepared by the comparative example is poor, the metal layer is uneven and continuous, and the adhesion performance is poor; the reason is that the crosslinking activator prepared by the invention has the characteristics of better catalytic activity and stronger adhesive force under the condition of micro silver.

It should be noted that, in all the above examples except the comparative example, the specific organic amine is not specifically limited to any organic amine, and any one or more of the short carbon chain primary amines (e.g., one or more of 2-pentylamine, 3-methyl-2-butylamine, sec-butylamine, or isopropylamine) having no more than 8 carbon atoms in the carbon chain of the organic amine can solve the technical problems and achieve the technical effects of the present invention, as long as the organic amine is described in the summary of the invention.

Claims

1. A crosslinking catalyst for preparing a patterned metal layer is characterized by comprising 3-15% of organic amine, 1-5% of an active source, 8-20% of solid polyurethane resin and 60-80% of an organic solvent in percentage by mass;

the organic amine is a compound in which one hydrogen atom in an ammonia molecule is substituted by alkyl;

the active source is one or more of soluble silver salt, soluble palladium salt or soluble nickel salt;

the organic solvent is one or more of isophorone, dibasic ester or diethylene glycol butyl ether acetate;

2. The crosslinking catalyst for preparing a patterned metal layer as claimed in claim 1, wherein the organic amine has a short carbon chain primary amine with a carbon chain having no more than 8 carbon atoms.

3. The crosslinking catalyst of claim 2, wherein the short carbon chain primary amine is one or more of 2-pentylamine, 3-methyl-2-butylamine, sec-butylamine, or isopropylamine.

4. The crosslinking catalyst for preparing a patterned metal layer according to claim 1, wherein the crosslinking catalyst has a viscosity of 3000 to 10000mPa · S, which is suitable for various subsequent printing or spraying processes.

5. A preparation method of a patterned metal layer is characterized by comprising the following steps:

step 1: printing a layer of cross-linking catalyst consistent with the target pattern of the graphical metal layer on the surface of the medium substrate; the crosslinking catalyst comprises 3-15% of organic amine, 1-5% of active source, 8-20% of solid polyurethane resin and 60-80% of organic solvent in percentage by mass; dissolving the solid polyurethane resin in the organic solvent, then adding the organic amine, mixing, stirring, performing acylation reaction, adding the active source, stirring, dispersing, and performing crosslinking reaction to obtain the crosslinking catalyst; the organic amine is a compound in which one hydrogen atom in an ammonia molecule is substituted by alkyl; the active source is one or more of soluble silver salt, soluble palladium salt or soluble nickel salt; the organic solvent is one or more of isophorone, dibasic ester or diethylene glycol butyl ether acetate;

step 2: fixing at constant temperature to fix the graphical cross-linking catalyst printed on the surface of the medium substrate; the constant temperature fixing temperature is 130-160 ℃, and the constant temperature fixing time is 1-5 minutes;

6. The method of claim 5, wherein the crosslinking catalyst used in step 1 is a short-carbon primary amine having no more than 8C atoms in the carbon chain of the organic amine.

7. The method of claim 6, wherein the short carbon chain primary amine is one or more of 2-pentylamine, 3-methyl-2-butylamine, sec-butylamine, or isopropylamine.

8. The method of claim 5, wherein the step of applying the crosslinking catalyst to the surface of the dielectric substrate comprises printing, spin coating, or printing.

9. The method for preparing the patterned metal layer according to claim 5, wherein the dielectric substrate comprises a flexible substrate and a rigid substrate, the flexible substrate is a polyethylene terephthalate, polyethylene naphthalate or polyimide substrate, and the rigid substrate is a resin plate, a ceramic substrate or a glass substrate.

10. The method of claim 5, wherein the metal deposition solution is an electroless copper plating solution, an electroless nickel plating solution, or an electroless silver plating solution.

11. The method of claim 5, wherein the step 3 comprises heating the metal deposit solution at a temperature of about 25 to about 50 ℃ for about 15 to about 25 minutes.