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CN-121975481-A - UV (ultraviolet) curing adhesive for FPC (Flexible printed Circuit) and preparation method thereof

CN121975481ACN 121975481 ACN121975481 ACN 121975481ACN-121975481-A

Abstract

The invention relates to the technical field of cured adhesives, and discloses a UV cured adhesive for FPC and a preparation method thereof; the preparation method comprises the following operation steps of mixing aliphatic polyurethane acrylic ester, reactive diluent and defoamer, heating to 50-60 ℃, stirring for 1-2 hours, adding modified polyurethane acrylic ester, photoinitiator and antioxidant, uniformly mixing, and filtering to obtain the UV curing adhesive. The ultraviolet curing adhesive has the advantages of being good in flexibility and curing speed, high in shrinkage rate, capable of reducing curing shrinkage rate and thermal stability by taking aliphatic polyurethane acrylate as a base material and taking trimethylolpropane triacrylate and siloxane ethylene glycol epoxy acrylate as reactive diluents in the scheme, and capable of improving thermal stability of the ultraviolet curing adhesive cooperatively by introducing modified polyurethane acrylate with Schiff base.

Inventors

  • LU LEI

Assignees

  • 东莞市仕友粘合材料有限公司

Dates

Publication Date
20260505
Application Date
20260227

Claims (9)

  1. 1. The UV curing adhesive for the FPC is characterized by comprising, by mass, 60-75 parts of aliphatic polyurethane acrylate, 20-25 parts of modified polyurethane acrylate, 12-18 parts of reactive diluent, 3-6 parts of photoinitiator, 1-2 parts of antioxidant and 0.5-2 parts of defoamer.
  2. 2. The UV-curable adhesive for FPC according to claim 1, wherein said reactive diluent comprises (3-5) 1 by mass of a siloxane glycol epoxy acrylate and a trimethylolpropane triacrylate.
  3. 3. The UV curing adhesive for the FPC is characterized in that the preparation method of the siloxane ethylene glycol epoxy acrylate is characterized in that (1) ethylene glycol diglycidyl ether and tetrabutylammonium bromide are mixed, the temperature is raised to 80-90 ℃, 3-butenoic acid and a polymerization inhibitor are added, stirring is continued for 2-3 hours, so that the ethylene glycol epoxy acrylate is obtained, (2) the ethylene glycol epoxy acrylate and Karstedt catalyst are added into isopropanol, and are mixed, heated to 65-75 ℃, and tetramethyl disiloxane is added, and stirring is carried out for 2-4 hours, so that the siloxane ethylene glycol epoxy acrylate is obtained.
  4. 4. The UV-curable adhesive for the FPC is characterized in that the raw materials of the ethylene glycol epoxy acrylate comprise, by mass, 10-15 parts of ethylene glycol diglycidyl ether, 0.5-1 part of tetrabutylammonium bromide, 7-8 parts of 3-butenoic acid and 0.1-0.2 part of polymerization inhibitor, and the raw materials of the siloxane ethylene glycol epoxy acrylate comprise, by mass, 8-10 parts of ethylene glycol epoxy acrylate, 0.07-0.12 part of Karstedt catalyst and 3-5 parts of tetramethyl disiloxane.
  5. 5. The UV curing adhesive for the FPC is characterized in that the preparation method of the modified polyurethane acrylate is that (1) p-phenylenediamine and 2, 4-dihydroxybenzaldehyde are added into ethanol to be mixed, reflux is carried out for 6-8 hours, recrystallization is carried out to obtain p-phenylenediamine-2, 4-dihydroxybenzaldehyde Schiff base, and (2) isophorone diisocyanate and polyethylene glycol are added into acetone to be mixed, dibutyl tin dilaurate is added to be heated for reaction, and p-phenylenediamine-2, 4-dihydroxybenzaldehyde Schiff base and hydroxyethyl acrylate are added to be continuously reacted to obtain the modified polyurethane acrylate.
  6. 6. The UV-curable adhesive for the FPC, which is disclosed in claim 5, is characterized in that the molar ratio of p-phenylenediamine to 2, 4-dihydroxybenzaldehyde is 1:2, and the raw materials of the modified polyurethane acrylic ester comprise, by mass, 25-30 parts of isophorone diisocyanate, 13-18 parts of polyethylene glycol, 0.5-1.2 parts of dibutyltin dilaurate, 8-12 parts of p-phenylenediamine-2, 4-dihydroxybenzaldehyde Schiff base and 3-6 parts of hydroxyethyl acrylate.
  7. 7. The UV-curable adhesive for FPC of claim 1, wherein the photoinitiator comprises (2-3) methyl benzoate and 2,4, 6-trimethylbenzoyl-diphenyl phosphine oxide in a mass ratio of (1-2).
  8. 8. The preparation method of the UV-curable adhesive for the FPC, which is disclosed in any one of claims 1-7, is characterized by comprising the following steps of mixing aliphatic polyurethane acrylate, reactive diluent and defoamer, heating to 50-60 ℃, stirring for 1-2 hours, adding modified polyurethane acrylate, photoinitiator and antioxidant, uniformly mixing, and filtering to obtain the UV-curable adhesive.
  9. 9. The method for preparing the UV-curable adhesive for the FPC according to claim 8, wherein the curing condition of the UV-curable adhesive is that the UV lamp irradiates 30-60 mW/cm 2 , and the distance is 50-70 mm.

Description

UV (ultraviolet) curing adhesive for FPC (Flexible printed Circuit) and preparation method thereof Technical Field The invention relates to the technical field of cured adhesives, in particular to a UV cured adhesive for FPC and a preparation method thereof. Background Flexible printed circuit boards (FPCs) are widely used in consumer electronics, automotive electronics and other fields due to their light, thin and flexible properties, and UV-curable adhesives are increasingly required during assembly. The existing UV curing adhesive for the FPC is mainly prepared from aliphatic polyurethane acrylate (PUA) and conventional reactive diluents, but has the problems that firstly, the curing shrinkage rate is high, the warping and circuit offset of FPC base materials are easily caused, the product precision is affected, and secondly, the heat resistance is insufficient, the adhesive is easy to soften and deform under high-temperature welding and long-term wet and hot service environments, and the requirements of people on high-end electronic equipment cannot be met. In summary, to solve the above problems, it is important to prepare a UV curable adhesive for FPC. Disclosure of Invention The invention aims to provide a UV curing adhesive for FPC and a preparation method thereof, which are used for solving the problems in the prior art. In order to achieve the above purpose, the present invention provides the following technical solutions: The UV curing adhesive for the FPC comprises, by mass, 60-75 parts of aliphatic polyurethane acrylate, 20-25 parts of modified polyurethane acrylate, 12-18 parts of reactive diluent, 3-6 parts of photoinitiator, 1-2 parts of antioxidant and 0.5-2 parts of defoamer. Preferably, the reactive diluent comprises siloxane glycol epoxy acrylate and trimethylolpropane triacrylate with the mass ratio of (3-5) to 1. The preparation method of the siloxane ethylene glycol epoxy acrylate comprises the steps of (1) mixing ethylene glycol diglycidyl ether and tetrabutylammonium bromide, heating to 80-90 ℃, adding 3-butenoic acid and a polymerization inhibitor, continuously stirring for 2-3 hours to obtain the ethylene glycol epoxy acrylate, (2) adding the ethylene glycol epoxy acrylate and Karstedt catalyst into isopropanol, mixing, heating to 65-75 ℃, adding tetramethyl disiloxane, and stirring for 2-4 hours to obtain the siloxane ethylene glycol epoxy acrylate. The optimized raw materials of the ethylene glycol epoxy acrylate comprise, by mass, 10-15 parts of ethylene glycol diglycidyl ether, 0.5-1 part of tetrabutylammonium bromide, 7-8 parts of 3-butenoic acid and 0.1-0.2 part of polymerization inhibitor, and the raw materials of the siloxane ethylene glycol epoxy acrylate comprise, by mass, 8-10 parts of ethylene glycol epoxy acrylate, 0.07-0.12 part of Karstedt catalyst and 3-5 parts of tetramethyl disiloxane. In the scheme, epoxy groups on ethylene glycol diglycidyl ether and carboxyl groups on 3-butenoic acid react under the catalysis of tetrabutylammonium bromide to obtain ethylene glycol epoxy acrylate containing allyl groups, and the allyl groups on the ethylene glycol epoxy acrylate react with Si-H on tetramethyl disiloxane under the action of Karstedt catalyst to obtain siloxane ethylene glycol epoxy acrylate. The optimized preparation method of the modified polyurethane acrylate comprises the steps of (1) adding p-phenylenediamine and 2, 4-dihydroxybenzaldehyde into ethanol, mixing, refluxing for 6-8 hours, recrystallizing to obtain p-phenylenediamine-2, 4-dihydroxybenzaldehyde Schiff base, (2) adding isophorone diisocyanate and polyethylene glycol into acetone, mixing, adding dibutyltin dilaurate, heating for reaction, adding p-phenylenediamine-2, 4-dihydroxybenzaldehyde Schiff base and hydroxyethyl acrylate, and continuously reacting to obtain the modified polyurethane acrylate. The optimized molar ratio of the p-phenylenediamine to the 2, 4-dihydroxybenzaldehyde is 1:2, and the raw materials of the modified polyurethane acrylic ester comprise, by mass, 25-30 parts of isophorone diisocyanate, 13-18 parts of polyethylene glycol, 0.5-1.2 parts of dibutyltin dilaurate, 8-12 parts of p-phenylenediamine-2, 4-dihydroxybenzaldehyde Schiff base and 3-6 parts of hydroxyethyl acrylate. Preferably, the raw materials of the photoinitiator comprise (2-3) methyl benzoate and 2,4, 6-trimethylbenzoyl-diphenyl phosphine oxide in a mass ratio of (1-2). The preparation method of the UV curing adhesive for the FPC comprises the following operation steps of mixing aliphatic polyurethane acrylic ester, reactive diluent and defoamer, heating to 50-60 ℃, stirring for 1-2 hours, adding modified polyurethane acrylic ester, photoinitiator and antioxidant, uniformly mixing, and filtering to obtain the UV curing adhesive. Preferably, the curing condition of the UV curing adhesive is that a UV lamp with the irradiation speed of 30-60 mW/cm 2 is used, and the distance is 50-70 mm. Compared with the prior art