CN111944360A

CN111944360A - Hot-melt type three-proofing paint and preparation method and use method thereof

Info

Publication number: CN111944360A
Application number: CN202010708576.9A
Authority: CN
Inventors: 廖沛锟
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-07-22
Filing date: 2020-07-22
Publication date: 2020-11-17

Abstract

The invention provides a hot-melt type three-proofing paint and a preparation method and a using method thereof, wherein the three-proofing paint consists of 1-3% of toner, 1-3% of antioxidant, 3-5% of flexibilizer, 20-30% of tackifier and 60-70% of polyolefin. The antioxidant is beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) isooctyl propionate, the tackifier is one or more of C5 petroleum resin, poly-alpha-methylstyrene resin and hydrogenated terpene resin, and the polyolefin is one or more of polyethylene, polypropylene, poly-1-butene and poly-4-methyl-1-pentene. The hot-melt type three-proofing paint prepared by the invention is solid during storage and transportation without adding a solvent, so that potential safety hazards caused by solvent volatilization and leakage in the storage process are avoided, the problems of swelling and damage of a packaging drum caused by solvent volatilization due to temperature change in the storage process are avoided, and the storage stability is high. In the using process, no solvent is volatilized, heating or ultraviolet illumination auxiliary curing is not needed, and the use is convenient, safe and environment-friendly.

Description

Hot-melt type three-proofing paint and preparation method and use method thereof

Technical Field

The invention belongs to the field of special coatings, and relates to a hot-melt type three-proofing paint, and a preparation method and a use method thereof.

Background

The printed circuit board is formed by interconnecting lines and printed elements from points to points on an insulating base material according to a predetermined design, and is a provider of electrical connection of electronic components. The circuit board is very common in daily life, and is small as a mobile phone, a U disk and a camera, and large as high-end products such as aerospace, high-speed rail vehicles and the like. With the increasing variety and quantity of electronic products, it is an important link to strictly control the quality of the circuit board to improve the competitiveness of the electronic products. In the practical application process, the service environment of the circuit board is complex and various, and can face environments such as humidity, high heat, salt mist, low temperature, vibration, high dust and the like, if corresponding effective protection is not carried out, the circuit board can rapidly generate the problems of corrosion, deformation, mildew, aging and the like, and finally the circuit is caused to lose efficacy, and equipment breaks down.

In order to reduce the damage of the external environment to the circuit board and ensure the normal operation of the equipment, protective paint, also called tri-proof paint, is often sprayed on the surface of the circuit board, the main chemical components of the protective paint are acrylate, silicone, polyurethane, epoxy resin and the like, and the working principle is to form a layer of protective film on the surface of the circuit board so as to prevent the circuit board from being damaged by the working environment, thereby improving the quality reliability of the circuit board.

At present, the three-proofing paint on the market is mostly liquid, adopts dry filming and reaction crosslinking film forming mechanism in order to form the protective coating on the circuit board, and this kind of mode can cause the solvent to volatilize, and VOC pollutes, causes the harm to user health, and a large amount of solvent content make the product storage, and the transportation, the fire prevention explosion-proof will be noted in the use, and the security reduces, and liquid product can need heating or ultraviolet irradiation at dry filming and reaction crosslinking in-process in addition, increases and uses the maintenance cost. And the existing product has poor coverage on the edge of the component for the high pin position, the protection performance can be reduced, and the circuit board can be found out to be damaged.

In the prior art, various improvement measures are provided for preventing organic solvents in three-proofing paint from volatilizing, for example, the invention patent with the application number of 201810113875.0 discloses a dip plate device for inhibiting the volatilization of the organic solvents in the three-proofing paint, and the dip plate device soaks a workpiece on a closed work box, so that the loss of the solvents is greatly reduced, the cost is reduced, the emission of VOCs is reduced, and the personal safety of workers is effectively protected; the invention patent application No. 201210474135.2 discloses a novel on-line selective tri-proof paint coater which prevents harmful gases from entering the surrounding environment through a relatively closed working environment and then exhausts the gases through an exhaust fan and an exhaust duct. Therefore, in the prior art, a mode of sealing a space is usually adopted to prevent the three-proofing paint organic solvent from volatilizing into the environment, but the measures cannot fundamentally solve the problem of volatilization of the three-proofing paint solvent. Even if evaporation can be prevented during use, there is still a risk of fire or explosion due to solvent spillage during storage.

Disclosure of Invention

In order to solve the problems, the invention provides the hot-melt type three-proofing paint, which effectively solves the problem of environmental pollution caused by volatilization of a coating solvent in the prior art, improves the storage and transportation safety, is simple in use method, does not need additional heating or illumination curing, and improves the use convenience.

The following specific technical scheme is adopted:

a hot-melt three-proofing paint is prepared from the following components: 1-3% of toner, 1-3% of antioxidant, 3-5% of toughening agent, 20-30% of tackifier and 60-70% of polyolefin.

The antioxidant can prevent fading and aging due to oxidation-reduction during use. Preferably, the antioxidant is isooctyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate.

Furthermore, the antioxidant is a mixture of beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) isooctanol propionate and bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate which are combined according to the mass ratio of 2:1, and the combination of the bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate and beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) isooctanol propionate can improve the heat resistance, and the combination of the antioxidant and the ultraviolet light absorber has a synergistic effect, so that the stability and the aging resistance can be further improved.

The toughening agent can increase the flexibility of the paint film, is also beneficial to the dispersion processing of the toner, and influences the adhesive force, the mechanical strength, the heat resistance, the cold resistance, the corrosion resistance and the like of the paint film. Preferably, the toughening agent is obtained by reacting succinic anhydride, polyethylene glycol, bisphenol A epoxy resin and an n-butyl ammonium bromide catalyst.

In one embodiment, the toughening agent is prepared by: step one, mixing succinic anhydride and polyethylene glycol according to the weight ratio of 1: 2.0 mol ratio, carrying out ring-opening reaction at 100-130 ℃ for 2-4h, when the acid value of the detection system reaches the theoretical value in the second step, adding liquid epoxy resin which is 1.5 times of the mole number of the succinic anhydride and n-butyl ammonium bromide catalyst which is 3-5% of the mole number of the succinic anhydride, reacting at 90-120 ℃ for 3-5h, measuring the acid value of the resin to be below 5mgKOH/g, and cooling to obtain the toughening agent.

The tackifier is used for improving the cohesiveness of the three-proofing paint and the adhesive force. Preferably, the tackifier is one or a combination of more than two of C5 petroleum resin, poly alpha-methyl styrene resin and hydrogenated terpene resin.

Preferably, the polyolefin is one of polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene.

The preparation method of the hot-melt type three-proofing paint comprises the following steps:

step one, respectively heating an antioxidant, a tackifier and polyolefin to be molten;

step two, mixing the melted oxidant, tackifier and polyolefin according to a certain proportion, and fully stirring until the mixture is uniform to obtain a pretreatment mixture;

step three, adding a toughening agent with a certain proportion into the pretreated mixture, and continuously stirring until the toughening agent is uniformly mixed;

adding toner, continuously stirring to ensure uniform mixing, and adding the toner for 10-20 times to obtain molten three-proofing paint;

and fifthly, extruding the molten three-proofing paint into a package at high pressure, cooling and packaging to obtain the hot-melt three-proofing paint.

Preferably, the melting temperature in step one is 150 ℃ to 220 ℃.

The application method of the hot-melt type three-proofing paint prepared by the application comprises the following steps: heating the hot-melt three-proofing paint to 180-190 ℃, dispensing or pressurizing and spraying the hot-melt three-proofing paint by using dispensing equipment, and cooling.

The three-proofing paint is prepared by adopting an antioxidant, a toughening agent, a tackifier and polyolefin matched with toner as raw materials, wherein the antioxidant, the tackifier and the polyolefin are respectively heated to be molten, then are uniformly mixed according to the proportion of 1-3% of the antioxidant, 20-30% of the tackifier and 60-70% of the polyolefin, then are added with 3-5% of the toughening agent, and finally are added with 1-3% of the toner in portions, so that the toner is prevented from being agglomerated and unevenly distributed. The prepared three-proofing paint is solid at normal temperature, and can be solidified and molded by dispensing or pressurized spraying through dispensing equipment after being heated to a molten state and cooled when in use. Because the raw materials are not added with the solvent and are solid during storage and transportation, potential safety hazards caused by solvent volatilization and leakage in the storage process are avoided, the problems of expansion and damage of a packaging drum caused by solvent volatilization due to temperature change in the storage process are avoided, and the storage stability is high. In the using process, no solvent is volatilized, heating or ultraviolet illumination auxiliary curing is not needed, and the use is convenient, safe and environment-friendly.

Compared with the prior art, the invention has the following beneficial effects:

the three-proofing paint provided by the invention has the advantages of no solvent, no VOC, cooling and forming, good storage stability, safe and convenient use, environmental protection, and simultaneously saves the cost of a tunnel furnace in the traditional process and saves the cost. The coating has the advantages of obvious excellent edge wrapping property, good adhesive force to various materials such as metal, plastic and the like, water resistance, moisture resistance and capability of resisting almost all chemical erosion at normal temperature. Easy to repair, can be directly welded and transmitted, and does not generate toxic gas.

Detailed Description

The present invention will be described in further detail by way of specific embodiments, but it should not be construed that the scope of the present invention is limited to the following examples. Various substitutions and alterations can be made by those skilled in the art and by conventional means without departing from the spirit of the method of the invention described above.

Example 1

A preparation method of hot-melt type three-proofing paint comprises the following steps:

step one, mixing succinic anhydride and polyethylene glycol according to the weight ratio of 1: 2.0 mol ratio, and carrying out ring opening reaction for 3h at 100 ℃;

step two, when the acid value of the system is detected to be a theoretical value, adding liquid epoxy resin which is 1.5 times of the mole number of the succinic anhydride and a n-butyl ammonium bromide catalyst which is 3% of the mole number of the succinic anhydride, reacting for 3.5h at 120 ℃, measuring the acid value of the resin to be less than 5mgKOH/g, and cooling to obtain the toughening agent;

step three, respectively heating beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) isooctyl propionate, C5 petroleum resin and polyethylene to be molten, wherein the melting temperature is 190 ℃;

step four, mixing the melted beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) isooctyl propionate, C5 petroleum resin and polyethylene according to the proportion of 1 percent, 30 percent and 65 percent respectively, and fully stirring until the mixture is uniformly mixed to obtain a pretreated mixture;

step five, adding 3% of toughening agent into the pretreated mixture, and continuously stirring until the toughening agent and the pretreated mixture are uniformly mixed;

step six, adding 1% of toner, continuously stirring at the same time, ensuring uniform mixing, and adding the toner for 15 times to obtain molten three-proofing paint;

and seventhly, extruding the molten three-proofing paint into a package at high pressure, cooling and packaging to obtain the hot-melt three-proofing paint.

Example 2

step three, heating beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) isooctyl propionate, poly alpha-methylstyrene resin and polypropylene to be molten respectively, wherein the melting temperature is 190 ℃;

step four, mixing the melted beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) isooctyl propionate, poly alpha-methylstyrene resin and polypropylene according to the proportion of 1 percent, 30 percent and 65 percent respectively, and fully stirring until the mixture is uniformly mixed to obtain a pretreatment mixture;

Example 3

step one, mixing succinic anhydride and polyethylene glycol according to the weight ratio of 1: 2.0 mol ratio, and carrying out ring opening reaction for 4h at 100 ℃;

step two, when the acid value of the system is detected to be a theoretical value, adding liquid epoxy resin which is 1.5 times of the mole number of the succinic anhydride and a n-butyl ammonium bromide catalyst which is 5% of the mole number of the succinic anhydride, reacting for 3.5h at 100 ℃, measuring the acid value of the resin to be less than 5mgKOH/g, and cooling to obtain the toughening agent;

respectively heating beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) isooctyl propionate, C5 petroleum resin and poly 1-butylene to be molten, wherein the melting temperature is 190 ℃;

step four, mixing the melted beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) isooctyl propionate, C5 petroleum resin and poly 1-butylene according to the proportion of 2 percent, 27 percent and 65 percent respectively, and fully stirring until the mixture is uniformly mixed to obtain a pretreated mixture;

step five, adding 5% of toughening agent into the pretreated mixture, and continuously stirring until the toughening agent and the pretreated mixture are uniformly mixed;

step six, adding 1% of toner, continuously stirring at the same time, and ensuring uniform mixing, wherein the toner is added in 10 times to obtain the molten three-proofing paint;

Example 4

step one, mixing succinic anhydride and polyethylene glycol according to the weight ratio of 1: 2.0 mol ratio, and carrying out ring opening reaction for 2h at 100 ℃;

step two, when the acid value of the system is detected to be a theoretical value, adding liquid epoxy resin which is 1.5 times of the mole number of the succinic anhydride and n-butyl ammonium bromide catalyst which is 3% of the mole number of the succinic anhydride, reacting for 5 hours at 120 ℃, measuring the acid value of the resin to be less than 5mgKOH/g, and cooling to obtain the toughening agent;

step three, respectively heating the antioxidant, the mixture of the C5 petroleum resin and the poly alpha-methylstyrene resin and the polyethylene to be molten, wherein the melting temperature is 190 ℃; wherein the antioxidant is a mixture of beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid isooctyl ester and bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate which are used in combination according to the mass ratio of 2: 1.

Step four, mixing the melted antioxidant, the mixture of the C5 petroleum resin and the poly alpha-methyl styrene resin and the polyethylene according to the proportion of 1 percent, 30 percent and 65 percent respectively, and fully stirring until the mixture is uniformly mixed to obtain a pretreatment mixture;

Comparative example 1

The self-drying three-proofing paint disclosed by application number CN 201410750949.3 and the preparation method thereof are adopted to prepare the three-proofing paint, and the preparation method specifically comprises the following steps:

(1) according to the weight ratio, 5% of hydrogenated rosin, 7% of hydrogenated carbon penta-resin, 2% of terpene resin, 3% of 1010 antioxidant, 2% of 354 leveling agent, 1.5% of mildew preventive tributyltin chloride and 1.5% of anti-skinning agent methylethylketoxime are respectively poured into a reaction kettle A;

(2) then putting 15% of dimethylbenzene and 5% of gasoline into the reaction kettle in sequence, and fully stirring until the dimethylbenzene and the gasoline are completely dissolved to obtain a mixture B;

(3) sequentially adding 20% of modified acrylic resin and 28% of modified epoxy resin into a reaction kettle C, sequentially adding the remaining 5% of dimethylbenzene and 5% of gasoline into the reaction kettle C, and stirring until the dimethylbenzene and the gasoline are completely and uniformly dissolved to obtain a mixture D;

(4) and (4) adding the mixture B when the mixture D is cooled to room temperature, and fully stirring the mixture B until the mixture is uniform to obtain a finished product of the three-proofing paint.

And (3) comparison test:

preparing a standard copper plate base material, namely putting a main printing ink agent and a hardening agent for the printed circuit board into a plastic cup in a mass ratio of 3:1, uniformly stirring, and standing for 10 min; making several 5cm x cm red copper sheets, and uniformly coating the uniformly mixed ink on one surface of the red copper sheets by using a soft brush. And then placing the substrate in an electric oven at 75 ℃ for 20min, raising the temperature to 150 ℃, standing for 60min, and taking out to obtain the circuit board substrate for testing.

The three-proofing paint obtained in the embodiments 1-4 of the invention is heated to be molten, then is put into spraying equipment to be respectively sprayed on copper plate base materials, and is cooled to be solidified at room temperature. Spraying the three-proofing paint spraying equipment prepared in the comparative example 1 on the copper plate substrate, then putting the circuit board into an oven for drying, setting the temperature at 60 ℃, drying for 30 minutes, and then taking out and cooling to room temperature.

The copper plate substrates obtained by spraying of examples 1 to 4 and comparative example 1 were subjected to a comparative test, and a total of 12 orthogonal scratches (the scratches all penetrate the paint film) were scribed on the paint film surface with a special test cutter, and the distance between adjacent scribes was 2mm, thereby forming a 5 × 5 grid. A 180 ° peel test was performed with the application of a special adhesive tape. The test results are reported below:

from the preparation process of the comparative example and the test results of examples 1 to 4 and comparative example 1, it can be seen that the hot-melt type three-proofing paint prepared by the method does not contain any solvent, so that the problem of solvent volatilization cannot exist in the using process, and the comparative example 1 adds 15% of xylene and 5% of gasoline, so that not only is the safety risk existed, but also the solvent volatilizes in the curing process and causes pollution to the environment; in addition, the hot-melt type three-proofing paint prepared by the method can be cured only by cooling at room temperature after being coated, so that the process is simplified, the efficiency is improved, and the comparative example needs to be dried in an oven. Finally, test results show that the preparation process of the paint does not need to add a solvent, the curing process is simple, and the paint still has good adhesive force, so that the hot-melt type three-proofing paint prepared by the method can have good adhesive force, can resist chemical corrosion, and also improves the environmental protection property and the safety.

Claims

1. The hot-melt three-proofing paint is characterized by being prepared from the following components:

1 to 3 percent of toner,

1 to 3 percent of antioxidant,

3 to 5 percent of toughening agent,

20 to 30 percent of tackifier,

60-70% of polyolefin.

2. The hot-melt three-proofing paint according to claim 1, wherein said antioxidant is isooctyl β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate.

3. The hot-melt type three-proofing paint according to claim 2, wherein the antioxidant is a mixture of isooctyl β - (3, 5-di-t-butyl-4-hydroxyphenyl) propionate and bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate in a mass ratio of 2: 1.

4. The hot-melt three-proofing paint according to claim 1, wherein the toughening agent is obtained by reacting succinic anhydride, polyethylene glycol, bisphenol A epoxy resin and n-butyl ammonium bromide catalyst.

5. The hot-melt conformal coating of claim 4, wherein the toughening agent is prepared by the steps of:

1) mixing succinic anhydride and polyethylene glycol according to the weight ratio of 1: 2.0 mol ratio, and the ring-opening reaction is carried out at 100-130 ℃ for 2-4 h;

2) when the acid value of the system is detected to be the theoretical value, adding liquid epoxy resin which is 1.5 times of the mole number of the succinic anhydride and n-butyl ammonium bromide catalyst which is 3-5% of the mole number of the succinic anhydride, reacting for 3-5h at 90-120 ℃, measuring the acid value of the resin to be below 5mgKOH/g, and cooling to obtain the toughening agent.

6. The hot-melt three-proofing paint according to claim 1, wherein said tackifier is one or a combination of two or more of C5 petroleum resin, poly-alpha-methylstyrene resin and hydrogenated terpene resin.

7. A hot-melt type three-proofing paint according to claim 1, wherein said polyolefin is one or more of polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene.

8. The method for preparing a hot-melt type three-proofing paint according to any one of claims 1 to 7, comprising the steps of:

1) respectively heating the antioxidant, the tackifier and the polyolefin to be molten;

2) mixing the melted oxidant, tackifier and polyolefin according to a certain proportion, and fully stirring until the mixture is uniform to obtain a pretreatment mixture;

3) adding a toughening agent in a certain ratio into the pretreatment mixture, and continuously stirring until the toughening agent and the pretreatment mixture are uniformly mixed;

4) adding the toner, continuously stirring to ensure uniform mixing, and adding the toner 10-20 times to obtain the molten three-proofing paint;

5) and extruding the molten three-proofing paint into a package at high pressure, cooling and packaging to obtain the hot-melt three-proofing paint.

9. The method for preparing a hot-melt type three-proofing paint according to claim 8, wherein the melting temperature in the step 1) is 150-220 ℃.

10. The use method of the hot-melt type three-proofing paint as claimed in any one of claims 1 to 7, wherein the hot-melt type three-proofing paint is heated to 180 ℃ to 190 ℃, dispensed by a dispensing device or sprayed under pressure, and cooled.