CN113621339B - Photochromic solder joint protective adhesive and preparation method and application thereof - Google Patents

Abstract

The invention provides a photochromic welding spot protection adhesive and a preparation method and application thereof, wherein the preparation raw materials of the welding spot protection adhesive comprise a combination of a monofunctional acrylate monomer, a polyurethane acrylate oligomer, a photoinitiator, epoxy resin and UV (ultraviolet) color-changing powder in a specific part; the welding spot protection adhesive is prepared by selecting a combination of a difunctional polyurethane acrylate oligomer and a multifunctional polyurethane acrylate oligomer as an oligomer, regulating and controlling the addition amount of each component and adding a specific part of UV color-changing powder, has moderate hardness, has excellent curing depth, has obvious color change before and after UV illumination and has easy repair performance, and has important research value.

Description

Photochromic solder joint protective glue and its preparation method and application

Technical field

The invention belongs to the technical field of adhesives, and specifically relates to photochromic solder joint protective adhesive and its preparation method and application.

Background technique

The solder joints on precision modules are also called pins, or PINs in English. They are the connections from the internal circuit of the integrated circuit (chip) to the peripheral circuit. The end of the lead is connected to the printed circuit board through soft soldering. (usually FPC soft board), in some precision manufacturing industries, such as module assembly, it is often necessary to use glue to protect the pin welding, and also to enhance its strength. This glue is called PIN Glue or solder joint protection glue, usually UV curing glue.

With the continuous development and progress of integrated circuits, ordinary UV curing glue can no longer meet the requirements, so research on glue used in integrated circuit packaging is also ongoing. CN108707447A discloses a strong bonding and highly conductive welding glue. The formula includes 5-15% tin, 10-20% bismuth, 5-15% naphthalene epoxy, 10-20% modified acrylic resin, 1 ~3% phenolic resin, 0.5~1.5% fumed silica, 0.5~1.5% adipic acid, 0.1~0.5% silane coupling agent, 5~15% hardener and the balance epoxy resin ; The welding glue provided by this invention not only has better adhesion, but also has excellent conductivity. It can avoid cracking and short circuit problems under high temperature and high humidity conditions, and is very suitable for electronic products with limited space. CN111826105A discloses an LED packaging glue and its use method and application. The LED packaging glue includes component A and component B, wherein the component A includes epoxy resin and antioxidant, and optional color. paste; the component B includes a curing agent, a hydroxyl-terminated polyurethane prepolymer, a polyol and an accelerator, and an optional ultraviolet absorber; the LED encapsulant obtained by this invention has good cold and heat shock resistance and resistance to Moisture and heat performance.

However, as a solder joint protective adhesive for precision manufacturing, due to the huge amount of devices that the assembly plant has to process every day, the solder joint protective adhesive may go to the next process in the production line without UV curing. At this time, it is necessary to provide means to prevent errors. The usual method is to affix a color-changing label on the parts tray. The label will change color when exposed to UV light. The discoloration of the label can be used to determine whether the entire tray of parts has been UV cured. However, this method cannot track the status of each part, and requires additional manual labeling process, which increases the cost and may cause missing labels, which is not conducive to use in mass production processes.

Therefore, developing a solder joint protective adhesive that has moderate hardness, excellent solidification depth and is photochromic is an urgent technical problem in this field.

Contents of the invention

In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a photochromic solder joint protective glue and its preparation method and application; the preparation raw materials of the solder joint protective glue include a specific proportion of monofunctional acrylate A combination of monomer-like, polyurethane acrylate oligomer photoinitiator, epoxy resin and UV color-changing powder; by selecting a combination of bifunctional polyurethane acrylate oligomer and multifunctional polyurethane acrylate oligomer as polyurethane acrylate oligomer The polymer and the above-mentioned components cooperate with each other to make the solder joint protective glue have moderate hardness, excellent curing depth and obvious color changes before and after UV irradiation, and are easy to repair, making it suitable for mass production of devices.

To achieve this goal, the present invention adopts the following technical solutions:

In a first aspect, the present invention provides a photochromic solder joint protective glue. The raw materials for preparing the solder joint protective glue include the following components in parts by weight: 25 to 45 parts by weight of monofunctional acrylate monomers, polyurethane 50-65 parts by weight of acrylate oligomer, 1-5 parts by weight of photoinitiator, 1-4 parts by weight of epoxy resin and 2-5 parts by weight of UV color-changing powder.

The polyurethane acrylate oligomer includes bifunctional polyurethane acrylate oligomer and multifunctional polyurethane acrylate oligomer.

The monofunctional acrylate monomer may be 27 parts by weight, 29 parts by weight, 31 parts by weight, 33 parts by weight, 35 parts by weight, 37 parts by weight, 39 parts by weight, 41 parts by weight or 43 parts by weight, etc.

The polyurethane acrylate oligomer may be 52 parts by weight, 54 parts by weight, 56 parts by weight, 58 parts by weight, 60 parts by weight, 61 parts by weight, 62 parts by weight, 63 parts by weight or 64 parts by weight, etc.

The photoinitiator can be 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight or 4.5 parts by weight, etc.

The epoxy resin may be 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight or 3.5 parts by weight, etc.

The UV color-changing powder can be 2.3 parts by weight, 2.6 parts by weight, 2.9 parts by weight, 3 parts by weight, 3.3 parts by weight, 3.6 parts by weight, 3.9 parts by weight, 4 parts by weight, 4.3 parts by weight, 4.6 parts by weight or 4.9 parts by weight wait.

On the one hand, the present invention introduces UV discoloration powder into the raw materials for preparing solder joint protective glue, so that the color of the solder joint protective glue can change while curing. This eliminates the need for additional manual discoloration labels, and whether each part has been UV curing can be visually observed from the color of the solder joint protective glue, which makes up for the shortcomings of the solder joint protective glue in the existing technology.

On the other hand, the solder joint protective glue needs to have a moderate hardness (D40~D60) in actual use to be able to withstand a certain deformation, and not be too soft to provide good strength; and because some areas The thickness of the glue is relatively large, so a solder joint protective glue with a certain curing depth is needed to prevent the bottom from being unable to solidify; it also needs to have repairability so that parts can be repaired and reused if they are assembled incorrectly. Adding UV color-changing powder directly to the solder joint protective glue will greatly affect the solidification depth of the solder joint protective glue, and will also cause its rework performance to deteriorate; the present invention selects bifunctional polyurethane acrylate oligomer and multifunctional polyurethane. The combination of acrylate oligomers, and controlling the total addition amount of polyurethane acrylate oligomers to a specific number of 50 to 65 parts by weight can ensure that the obtained solder joint protective glue has a good curing depth, and at the same time, the It has good rework performance.

In summary, the photochromic solder joint protective adhesive provided by the present invention selects a specific proportion of bifunctional polyurethane acrylate oligomer and multifunctional polyurethane acrylate oligomer, so that the two create synergy and control the total addition of the two. The amount is 50 to 65 parts by weight, and a specific amount of UV color-changing powder is added so that it will not affect the performance of the solder joint protective glue; in the end, the photochromic solder joint protective glue can be obtained with moderate hardness , Excellent curing depth can avoid the problem that the bottom cannot be completely cured. It has rework performance, and the color changes obviously before and after UV illumination, so that parts can be repaired in time when assembly errors occur. It is suitable for use in the production of large-volume devices and has important research significance. .

Preferably, the monofunctional acrylate monomer includes isobornyl methacrylate, isobornyl acrylate, hydroxyethyl methacrylate, tetrahydrofuran acrylate, tetrahydrofuran methacrylate, dodecyl acrylate, Any one or a combination of at least two of dialkyl methacrylate, isodecyl acrylate, N-vinyl caprolactam or N-vinyl pyrrolidone.

Preferably, the bifunctional urethane acrylate oligomer includes bifunctional aliphatic urethane acrylate oligomer and/or bifunctional aromatic urethane acrylate oligomer.

Preferably, the content of the bifunctional polyurethane acrylate oligomer in the raw materials for preparing the solder joint protective glue is 30 to 50 parts by weight, such as 32 parts by weight, 34 parts by weight, 36 parts by weight, 38 parts by weight, and 40 parts by weight. , 42 parts by weight, 44 parts by weight, 46 parts by weight or 48 parts by weight, etc.

Preferably, the bifunctional aliphatic polyurethane acrylate oligomer can be selected from one or more of the following commercially available products, for example, Sartomer CN8003, CN8010, CN8881, CN8883, CN8887, CN8888, CN9004, CN9007 can be selected , CN9014, CN9023, CN9028, CN965, CN969, CN980, CN981 or CN996.

Preferably, the bifunctional aromatic polyurethane acrylate oligomer can be selected from one or more of the following commercially available products; for example, Sartomer CN9167, CN978, CN9782, CN9783 or CN992 can be selected.

Preferably, the multifunctional urethane acrylate oligomer includes multifunctional aliphatic urethane acrylate oligomer and/or multifunctional aromatic urethane acrylate oligomer.

Preferably, the multifunctional polyurethane acrylate oligomer includes a polyurethane acrylate oligomer with a functionality of 6 to 9 (for example, 7 or 8).

Preferably, the content of bifunctional polyurethane acrylate oligomer in the raw materials for preparing the solder joint protective glue is 10 to 25 parts by weight, such as 12 parts by weight, 14 parts by weight, 16 parts by weight, 18 parts by weight, and 20 parts by weight. , 21 parts by weight, 22 parts by weight, 23 parts by weight or 24 parts by weight, etc.

Preferably, the multifunctional aliphatic polyurethane acrylate oligomer can be selected from one or more of the following commercially available products; for example, Sartomer CN8000, CN8011, CN8885, CN9006, CN9010, CN9013, CN9026 or CN9110 can be selected wait.

Preferably, the multifunctional aromatic polyurethane acrylate oligomer can be Sartomer CN9165.

Preferably, the photoinitiator includes 1-hydroxycyclohexyl phenyl ketone, 2,4,6-(trimethylbenzoyl)diphenylphosphorus oxide, 2-methyl-1-(4-methyl Thiophenyl)-2-morpholinyl-1-propanone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-phenylbenzyl-2-dimethylamine-1-( 4-morpholinobenzylphenyl)butanone, methyl benzoylformate, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-isopropylthiaxanthone, benzoin bis Any one or a combination of at least two of methyl ether, dimethylbenzoyl ketal or benzophenone, further preferably 1-hydroxycyclohexyl phenyl ketone and phenyl bis(2,4,6 - Combination of trimethylbenzoyl)phosphine oxides.

Preferably, the epoxy resin includes bisphenol A epoxy resin or bisphenol F epoxy resin.

Preferably, the UV color-changing powder includes photochromic materials. For example, you can choose the photo-changing powder series products from Shenzhen Bianhe Chemical Industry.

The UV color-changing powder in the present invention is an ultraviolet-sensitive material. Its initial color is translucent milky white. After absorbing ultraviolet rays, it can turn into red or various other colors. The color depth deepens as the ultraviolet irradiation time increases, and the color change is: Irreversible changes.

Preferably, the raw materials for preparing the solder joint protective glue also include any one or a combination of at least two of antioxidants, dispersants or fillers.

Preferably, the antioxidant content in the raw materials for preparing the solder joint protective glue is 0 to 1 part by weight and not equal to 0, such as 0.1 part by weight, 0.2 part by weight, 0.3 part by weight, 0.4 part by weight, 0.5 part by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight or 0.9 parts by weight, etc.

Preferably, the content of the dispersant in the raw materials for preparing the solder joint protective glue is 0 to 2 parts by weight and not equal to 0, such as 0.2 parts by weight, 0.4 parts by weight, 0.6 parts by weight, 0.8 parts by weight, 1 part by weight, 1.2 parts by weight parts by weight, 1.4 parts by weight, 1.6 parts by weight or 1.8 parts by weight, etc.

Preferably, the filler content in the raw materials for preparing the solder joint protective glue is 0 to 5 parts by weight and equal to 0, such as 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, and 3 parts by weight. , 3.5 parts by weight, 4 parts by weight or 4.5 parts by weight, etc.

In a second aspect, the present invention provides a method for preparing solder joint protective glue as described in the first aspect, the preparation method comprising the following steps:

(1) Mix monofunctional acrylate mono- and difunctional polyurethane acrylate oligomers and multifunctional polyurethane acrylate oligomers to obtain a transparent mixture;

(2) Mix the transparent mixture obtained in step (1), the photoinitiator and the epoxy resin to obtain a uniform mixture;

(3) Mix the homogeneous mixture obtained in step (2), UV discoloration powder, optional antioxidant, optional dispersant and optional filler to obtain the solder joint protective glue.

Preferably, the mixing in step (1) is carried out under stirring conditions, preferably at a stirring speed of 100 to 4000 rpm (such as 500 rpm, 1000 rpm, 1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm or 3500 rpm).

Preferably, the mixing temperature in step (1) is 10-40°C, such as 13°C, 16°C, 19°C, 23°C, 26°C, 29°C, 33°C, 36°C or 39°C, etc.

Preferably, the mixing time in step (1) is 10 to 60 min, such as 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min or 55 min, etc.

Preferably, the mixing in step (2) is carried out under stirring conditions, preferably at a stirring speed of 1000 to 3000 rpm (such as 1200 rpm, 1400 rpm, 1600 rpm, 1800 rpm, 2000 rpm, 2200 rpm, 2400 rpm, 2600 rpm or 2800 rpm, etc.). .

Preferably, the mixing temperature in step (2) is 20-40°C, such as 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C, 36°C or 38°C, etc.

Preferably, the mixing time in step (2) is 15 to 40 min, such as 17 min, 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, 32 min, 34 min, 36 min or 38 min, etc.

In a third aspect, the present invention provides an application of the photochromic solder joint protective glue described in the first aspect in module assembly.

Preferably, the application includes pin glue used in module assembly.

Compared with the existing technology, the present invention has the following beneficial effects:

(1) The raw materials for preparing the photochromic solder joint protective glue provided by the present invention include a specific proportion of monofunctional acrylate monomers, bifunctional polyurethane acrylate oligomers, and multifunctional polyurethane acrylate oligomers. , a combination of photoinitiator, epoxy resin and UV color-changing powder; the solder point protective glue limits the dosage of each component and adds a specific portion of UV color-changing powder, so that the obtained solder point protective glue has moderate hardness , excellent curing depth and easy rework performance, and the color changes significantly before and after UV irradiation, making it suitable for use in mass-produced devices.

(2) Specifically, the hardness of the solder joint protective glue obtained by the present invention is in the range of D40 to D60, the curing depth exceeds 1 mm, the rework performance can reach level 1, and the color changes can be recognized by the naked eye.

Detailed ways

The technical solution of the present invention will be further described below through specific implementations. Those skilled in the art should understand that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

Example 1

A photochromic solder joint protective glue. The raw materials for preparing the solder joint protective glue include the following components in parts by weight: 25 parts by weight of isobornyl methacrylate, bifunctional polyurethane acrylate oligomer (Shado 45 parts by weight of polyfunctional polyurethane acrylate oligomer (Sardoma, CN8000), 20 parts by weight of 1-hydroxycyclohexyl phenyl ketone, and bisphenol A epoxy resin (CAS: 25085 -99-8) 3 parts by weight and UV color changing powder (Shenzhen Bianhe Chemical) 5 parts by weight;

The preparation method of the photochromic solder joint protective glue provided in this embodiment includes the following steps:

(1) Mix isobornyl methacrylate, bifunctional polyurethane acrylate oligomer and multifunctional polyurethane acrylate oligomer at 30°C and 2000 rpm for 50 minutes to obtain a transparent mixture;

(2) Mix the transparent mixture obtained in step (1), 1-hydroxycyclohexyl phenyl ketone and epoxy resin at a rotation speed of 1500 rpm for 20 minutes to obtain a uniform mixture;

(3) Mix the uniform mixture obtained in step (2) and UV color-changing powder until the scraper fineness reaches 50 μm or less and stop mixing to obtain the solder joint protective glue.

Example 2

A kind of photochromic solder joint protective glue. The raw materials for preparing the solder joint protective glue include the following components in parts by weight: 45 parts by weight of isobornyl acrylate, bifunctional polyurethane acrylate oligomer (Sardoma includes , CN9167) 30 parts by weight, multifunctional polyurethane acrylate oligomer (Sartoma, CN8000) 20 parts by weight, 1 weight part of 2,4,6-(trimethylbenzoyl)diphenylphosphorus oxide, bis(trimethylbenzoyl)diphenylphosphorus oxide 1 part by weight of phenol A epoxy resin (CAS: 25085-99-8) and 3 parts by weight of UV color-changing powder (Shenzhen Bianhe Chemical);

The preparation method is the same as Example 1.

Example 3

A photochromic solder joint protective glue. The raw materials for preparing the solder joint protective glue include the following components in parts by weight: 31 parts by weight of hydroxyethyl methacrylate, bifunctional polyurethane acrylate oligomer (Shado 50 parts by weight of multifunctional polyurethane acrylate oligomer (Sardoma, CN9167), 10 parts by weight of 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl- 1-5 parts by weight of acetone, 2 parts by weight of bisphenol A epoxy resin (CAS: 25085-99-8) and 2 parts by weight of UV color-changing powder (Shenzhen Bianhe Chemical);

The preparation method is the same as Example 1.

Example 4

A photochromic solder joint protective glue. The raw materials for preparing the solder joint protective glue include the following components in parts by weight: 32 parts by weight of isobornyl methacrylate, bifunctional polyurethane acrylate oligomer (Shado 35 parts by weight of multifunctional polyurethane acrylate oligomer (Sardoma, CN8000), 1 part by weight of 1-hydroxycyclohexyl phenyl ketone, and bisphenol A epoxy resin (CAS: 25085 -99-8) 3 parts by weight and UV color changing powder (Shenzhen Bianhe Chemical) 4 parts by weight;

The preparation method is the same as Example 1.

Example 5

A photochromic solder joint protective glue. The raw materials for preparing the solder joint protective glue include the following components in parts by weight: 37 parts by weight of isobornyl methacrylate, bifunctional polyurethane acrylate oligomer (Shado 40 parts by weight of multifunctional polyurethane acrylate oligomer (Sardoma, CN8000), 3 parts by weight of 1-hydroxycyclohexyl phenyl ketone, and bisphenol A epoxy resin (CAS: 25085 -99-8) 1 part by weight and UV color changing powder (Shenzhen Bianhe Chemical) 3 parts by weight;

The preparation method is the same as Example 1.

Example 6

A photochromic solder joint protective glue. The raw materials for preparing the solder joint protective glue include the following components in parts by weight: 40 parts by weight of isobornyl methacrylate, bifunctional polyurethane acrylate oligomer (Shado Mar, CN9167) 32 parts by weight, multifunctional polyurethane acrylate oligomer (Sartoma, CN8000) 18 parts by weight, 4 parts by weight of 1-hydroxycyclohexylphenyl ketone, bisphenol A epoxy resin (CAS: 25085 -99-8) 4 parts by weight and UV color changing powder (Shenzhen Bianhe Chemical) 2 parts by weight;

The preparation method is the same as Example 1.

Comparative example 1

A photochromic solder joint protective glue. The raw materials for preparing the solder joint protective glue include the following components in parts by weight: 53 parts by weight of isobornyl methacrylate, bifunctional polyurethane acrylate oligomer (Shado 25 parts by weight of multifunctional polyurethane acrylate oligomer (Sardoma, CN8000), 2 parts by weight of 1-hydroxycyclohexyl phenyl ketone, and bisphenol A epoxy resin (CAS: 25085 -99-8) 2 parts by weight and UV color changing powder (Shenzhen Bianhe Chemical) 3 parts by weight;

The preparation method is the same as Example 1.

Comparative example 2

A photochromic solder joint protective glue. The raw materials for preparing the solder joint protective glue include the following components in parts by weight: 20 parts by weight of isobornyl methacrylate, bifunctional polyurethane acrylate oligomer (Shado 55 parts by weight of polyfunctional polyurethane acrylate oligomer (Sardoma, CN8000), 20 parts by weight of 1-hydroxycyclohexyl phenyl ketone, and bisphenol A epoxy resin (CAS: 25085 -99-8) 1 part by weight and UV color changing powder (Shenzhen Bianhe Chemical) 2 parts by weight;

The preparation method is the same as Example 1.

Comparative example 3

A photochromic solder joint protective glue. The raw materials for preparing the solder joint protective glue include the following components in parts by weight: 25.8 parts by weight of isobornyl methacrylate, bifunctional polyurethane acrylate oligomer (Shado Ma, CN9167) 46.5 parts by weight, multifunctional polyurethane acrylate oligomer (Sartoma, CN8000) 20.7 parts by weight, 2 parts by weight of 1-hydroxycyclohexylphenyl ketone and UV discoloration powder (Shenzhen Bianhe Chemical) 5 parts by weight;

The preparation method is the same as Example 1.

Comparative example 4

A photochromic solder joint protective glue. The raw materials for preparing the solder joint protective glue include the following components in parts by weight: 30 parts by weight of isobornyl methacrylate, bifunctional polyurethane acrylate oligomer (Shado 35 parts by weight of polyfunctional polyurethane acrylate oligomer (Sardoma, CN8000), 5 parts by weight of 1-hydroxycyclohexyl phenyl ketone, and bisphenol A epoxy resin (CAS: 25085 -99-8) 4 parts by weight and UV color changing powder (Shenzhen Bianhe Chemical) 6 parts by weight;

The preparation method is the same as Example 1.

Comparative example 5

A photochromic solder joint protective glue, which is different from Example 1 in that the raw materials for preparing the solder joint protective glue include the following components in parts by weight: 25 parts by weight of isobornyl methacrylate, bifunctional 45 parts by weight of polyurethane acrylate oligomer (Sardoma, CN9167), 20 parts by weight of multifunctional polyurethane acrylate oligomer (Sardoma, CN8000), 2 parts by weight of 1-hydroxycyclohexyl phenyl ketone and bis- 3 parts by weight of phenol A epoxy resin (CAS:25085-99-8);

The preparation method is the same as Example 1.

Comparative example 6

A photochromic solder joint protective glue, which differs from Example 1 in that no bifunctional polyurethane acrylate oligomer is added, the addition amount of multifunctional polyurethane acrylate oligomer is 65 parts by weight, and other components The ingredients, dosage and preparation method are the same as those in Example 1.

Comparative example 7

A photochromic solder joint protective glue, which differs from Example 1 in that no multifunctional polyurethane acrylate oligomer is added, the addition amount of the bifunctional polyurethane acrylate oligomer is 65 parts by weight, and the other components The ingredients, dosage and preparation method are the same as those in Example 1.

Performance Testing:

(1) Shore hardness: Take 2g of solder joint protective glue and make it into a disc with a diameter of 3cm in the mold. Use a UV-LED ultraviolet lamp, such as IGE's XC210 with a wavelength of 365nm, and use a positive UV energy of 5000mJ/ ^cm2 . Curing is performed once on each side, and after 24 hours, a digital Shore hardness tester is used to detect the hardness of the cured film;

(2) Curing depth: Use UV-LED lamp (IGE's XC210, wavelength 365nm) to cure the solder joint protective glue at a light intensity of 500mW/cm ² , curing for 10 seconds, total energy 5000mJ/cm ² , the test is complete The thickness of the cured solder joint protective glue is the curing depth;

(3) Reworkability: Coat the PIN pin with solder joint protective glue, place it in an 80°C oven after UV curing, and bake for 10 minutes; after taking it out, use tweezers to pick up the adhesive strip and observe whether it can be completely peeled off from the PIN pin. Next, rate it based on whether there is any residual glue on the PIN foot. 1 means no glue residue at all → 5 means it is completely stuck on the PIN foot and cannot be peeled off;

(4) Color change after UV curing: Apply the solder joint protective glue on the PIN foot and observe the color change before and after UV curing. If the color change cannot be clearly distinguished, it will be counted as 5; the color change requires placing the glue before and after UV together in a parallel ratio. The talent area is counted as 3; the color change can be noticed without placing the front and rear UV glue together and is scored as 2; the color difference between the front and back is huge and it is very obvious to the naked eye, which is counted as 1.

The solder joint protective adhesives provided in Examples 1 to 6 and Comparative Examples 1 to 7 were tested according to the above test method. The test results are as shown in Table 1:

Table 1

Shore hardness Curing depth(mm) Rework performance Color changes Example 1 D45 1.35 1 1 Example 2 D60 1.15 1 2 Example 3 D40 1.45 1 2 Example 4 D54 1.25 1 1 Example 5 D51 1.3 1 2 Example 6 D57 1.25 1 2 Comparative example 1 D61 0.75 1 1 Comparative example 2 D34 1.6 3 2 Comparative example 3 D46 1.35 4 1 Comparative example 4 D50 0.85 2 1 Comparative example 5 D50 2.05 1 5 Comparative example 6 D64 1.05 3 1 Comparative example 7 D30 2.4 3 1

According to the data in Table 1, it can be seen that when the added amounts of each component in the raw materials are within the specific range set by the present invention, the solder joint protective glue obtained has excellent comprehensive performance and can be used as UV color-changing pin glue; Specifically, the hardness of the solder joint protective glue obtained in Examples 1 to 6 is in the range of D40 to D60, the curing depth exceeds 1 mm, the rework performance can reach level 1, and the color changes can be identified with the naked eye.

Comparing Example 1 and Comparative Examples 1 to 2, it can be found that when the added amount of polyurethane acrylate oligomer is too small and the added amount of acrylate monomer is too large (Comparative Example 1), the curing depth of the solder joint protective glue obtained is not enough. Good. When the amount of polyurethane acrylate oligomer added is too high and the amount of acrylate monomer added is too small (Comparative Example 2), the hardness of the solder joint protective glue obtained is low. During rework, the adhesive strip is too soft. It is easy to break and remain on the PIN pin; Comparing Example 1 and Comparative Example 3, it can be found that the solder joint protective glue obtained when no epoxy resin is added has poor rework performance and has a serious phenomenon of residual glue, which greatly affects The rework effect is improved; further comparing Example 1 and Comparative Examples 4 to 5, it can be found that when the amount of UV discoloration material added is too high (Comparative Example 4), the curing depth of the solder joint protective glue obtained is not good, and the rework performance is also affected. There is a certain influence, but when no UV discoloration material is added to the preparation raw materials, the solder joint protective glue (Comparative Example 5) has no color change; finally, comparing Example 1 and Comparative Examples 6 to 7, it can be found that when the preparation raw materials are added with low The polymers are all multifunctional polyurethane acrylate oligomers (Comparative Example 6). The hardness of the solder joint protective glue obtained is relatively high. During repair, the adhesive strips are too hard and easy to break, resulting in residual glue. They are all bifunctional polyurethane acrylic. When using ester oligomer (Comparative Example 7), the hardness of the solder joint protective glue is low. During rework, the adhesive strip is soft and easy to break and remains on the PIN pin; and the rework performance is poor in both cases.

The applicant declares that the present invention illustrates a photochromic solder joint protective glue and its preparation method and application through the above embodiments, but the present invention is not limited to the above embodiments, which does not mean that the present invention must rely on the above Embodiments can be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacement of raw materials of the product of the present invention, addition of auxiliary ingredients, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims (23)

1. The photochromic solder joint protective adhesive is characterized by comprising the following raw materials in parts by weight: 25-45 parts of monofunctional acrylate monomer, 30-50 parts of difunctional polyurethane acrylate oligomer, 10-25 parts of multifunctional polyurethane acrylate oligomer, 1-5 parts of photoinitiator, 1-4 parts of epoxy resin and 2-5 parts of UV color-changing powder;

the UV color-changing powder is an ultraviolet sensitive material, the initial color is semitransparent and milky white, the color becomes other colors after absorbing ultraviolet rays, and the color depth deepens along with the increase of the ultraviolet irradiation time.

2. The solder joint protective paste of claim 1, wherein the monofunctional acrylate monomer comprises any one or a combination of at least two of isobornyl methacrylate, isobornyl acrylate, hydroxyethyl methacrylate, tetrahydrofuranacrylate, tetrahydrofuranmethacrylate, dodecyl acrylate, dodecyl methacrylate, or isodecyl acrylate.

3. Solder joint protective glue according to claim 1, characterized in that the difunctional urethane acrylate oligomer comprises a difunctional aliphatic urethane acrylate oligomer and/or a difunctional aromatic urethane acrylate oligomer.

4. The solder joint protective paste of claim 1, wherein the multifunctional urethane acrylate oligomer comprises a 6-9 functionality urethane acrylate oligomer.

5. The solder joint protective paste of claim 1, wherein the multifunctional urethane acrylate oligomer comprises a multifunctional aliphatic urethane acrylate oligomer and/or a multifunctional aromatic urethane acrylate oligomer.

6. The solder joint protective paste of claim 1, wherein the photoinitiator comprises any one or a combination of at least two of 1-hydroxycyclohexylphenyl ketone, 2,4,6- (trimethylbenzoyl) diphenyl phosphate, 2-methyl-1- (4-methylthiophenyl) -2-morpholinyl-1-propanone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-phenylbenzyl-2-dimethyl-amine-1- (4-morpholinylphenyl) butanone, methyl benzoate, phenylbis (2, 4, 6-trimethylbenzoyl) phosphine oxide, 2-isopropylthioxanthone, benzoin dimethyl ether, dimethylbenzoyl ketal, or benzophenone.

7. The paste as claimed in claim 6, wherein the photoinitiator is a combination of 1-hydroxycyclohexyl phenyl ketone and phenyl bis (2, 4, 6-trimethylbenzoyl) phosphine oxide.

8. The solder joint protective paste of claim 1, wherein the epoxy resin comprises bisphenol a epoxy resin or bisphenol F epoxy resin.

9. The welding spot protection glue according to claim 1, wherein the raw materials for preparing the welding spot protection glue further comprise any one or a combination of at least two of an antioxidant, a dispersing agent and a filler.

10. The welding spot protection glue according to claim 9, wherein the content of the antioxidant in the preparation raw material of the welding spot protection glue is 0-1 weight part and is not equal to 0.

11. The welding spot protection glue according to claim 9, wherein the content of the dispersing agent in the preparation raw material of the welding spot protection glue is 0-2 parts by weight and is not equal to 0.

12. The welding point protection glue according to claim 9, wherein the filler content in the raw material for preparing the welding point protection glue is 0-5 parts by weight and is not equal to 0.

13. A method for preparing the solder joint protective paste according to any one of claims 1 to 12, comprising the steps of:

(1) Mixing a monofunctional acrylate monomer, a difunctional urethane acrylate oligomer and a multifunctional urethane acrylate oligomer to obtain a transparent mixture;

(2) Mixing the transparent mixture obtained in the step (1), a photoinitiator and epoxy resin to obtain a uniform mixture;

(3) Mixing the uniform mixture obtained in the step (2), UV color-changing powder, optional antioxidant, optional dispersing agent and optional filler to obtain the solder joint protective adhesive.

14. The method of claim 13, wherein the mixing of step (1) is performed under stirring.

15. The method according to claim 14, wherein the mixing in the step (1) is performed under stirring at a rotation speed of 100 to 4000 rpm.

16. The method of claim 13, wherein the temperature of the mixing in step (1) is 10 to 40 ℃.

17. The method of claim 13, wherein the mixing in step (1) is for a period of 10 to 60 minutes.

18. The method of claim 13, wherein the mixing of step (2) is performed under stirring.

19. The method according to claim 18, wherein the mixing in the step (2) is performed under stirring at a rotation speed of 1000 to 3000 rpm.

20. The method of claim 13, wherein the temperature of the mixing in step (2) is 20 to 40 ℃.

21. The method of claim 13, wherein the mixing in step (2) is for 15 to 40 minutes.

22. Use of a photochromic solder joint protective paste according to any one of claims 1 to 12 in module assembly.

23. The use of claim 22, wherein the use comprises a pin paste for use in module assembly.