Delayed curing UV adhesive and preparation method thereof

Abstract

The invention discloses a delayed curing UV (ultraviolet) adhesive and a preparation method thereof, and relates to the technical field of adhesives, and the delayed curing UV adhesive is prepared from the following components in parts by weight: 50-80 parts of bisphenol A epoxy resin, 1-10 parts of naphthalene ring epoxy resin, 5-10 parts of light-cured resin and 1-5 parts of a photoinitiator. The UV adhesive has excellent mechanical properties after being cured, and can realize delayed curing at the same time.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesives and relates to UV glue, in particular to delayed curing UV glue and a preparation method thereof. Background Art

[0002] As the size of products in the fields of optical fiber, mobile phones, headphones, home appliances, computers, and medical treatments are designed to be smaller and smaller, the precision requirements of products are getting higher and higher. This means that many structures in the products cannot be exposed to UV light and can only be bonded with thermosetting glue or AB two-component glue. Thermosetting glue and AB two-component glue themselves have certain defects: the thermosetting time of thermosetting glue is long, and the expansion coefficient of AB two-component glue is large, which makes it impossible to use it in precision finished products. For example, in the field of optical fiber, a glue with a high refractive index and an extremely low expansion coefficient is required at the optical fiber joint. The existing glue can only meet the numerical requirements of high refractive index (1.56) by using heat-curing type. At this time, the overall thermal curing process of the glue takes about two hours.

[0003] The Chinese invention patent with application number 202110670453.5 discloses a delayed curing UV adhesive for bonding transparent media such as glass and glass, glass and aluminum sheets, and non-transparent media such as aluminum sheets and aluminum sheets, aluminum sheets and plastics, and a preparation method thereof. Its main components include: prepolymer accounting for 40-65% of the weight of the UV adhesive, epoxy resin accounting for 20-40% of the weight of the UV adhesive, active monomer accounting for 15-25% of the weight of the UV adhesive, auxiliary agent accounting for 1-3% of the weight of the UV adhesive, silane coupling agent accounting for 0.5-2.0% of the weight of the UV adhesive, antioxidant accounting for 0.5-2.0% of the weight of the UV adhesive, photoinitiator A accounting for 0.5-2% of the weight of the UV adhesive, and photoinitiator B accounting for 0.5-5% of the weight of the UV adhesive. The delayed curing optical UV adhesive is very suitable for bonding non-transparent media, which changes the characteristic that the existing commercially available UV adhesive can only bond the adherend to at least one side of the transparent medium.

[0004] The Chinese invention patent with application number 202110124177.2 discloses a UV delayed curing adhesive and a preparation method thereof, comprising the following raw materials: 60-90 parts of epoxy resin, 5-20 parts of polycaprolactone polyol, 1-10 parts of cationic curing agent, 0.01-0.1 parts of isopropyl thioxanthone, etc.; the application can effectively control the delay time of the colloid after light activation and the polymerization rate of the colloid after curing by adding isopropyl thioxanthone and epoxy resin. The polymerization rate of the colloid is increased to more than 99% by a reasonable amount of isopropyl thioxanthone. The adhesive has a smooth and non-sticky surface after curing and has good mechanical properties.

[0005] Although the above-mentioned delayed curing UV glue can play a role in delayed curing to a certain extent, it usually cannot meet the performance requirements of excellent mechanical properties after curing. Summary of the invention

[0006] In order to solve the above technical problems, the object of the present invention is to provide a delayed curing UV adhesive, which has excellent mechanical properties after curing and can also achieve delayed curing.

[0007] In order to achieve the above object, the present invention provides a delayed curing UV adhesive, which comprises the following components in parts by weight: 50-80 parts of bisphenol A epoxy resin, 1-10 parts of naphthalene epoxy resin, 5-10 parts of photocurable resin, and 1-5 parts of photoinitiator.

[0008] Preferably, the bisphenol A epoxy resin has an epoxy equivalent of 175 to 200 g / mol.

[0009] Preferably, the bisphenol A epoxy resin is an epoxy resin with the trade name of E54 or 0164, which is provided by Nantong Xingchen Synthetic Materials Co., Ltd.

[0010] Preferably, the naphthalene ring epoxy resin is a naphthyl difunctional epoxy resin, and the epoxy value is 0.65-0.73 equivalent / 100g.

[0011] Preferably, the naphthalene ring epoxy resin is EBA-65 naphthalene type epoxy resin, which is provided by Shanghai Huayi Resin Co., Ltd.

[0012] Preferably, the photocurable resin is a hyperbranched poly(urethane-amine) having a hydroxyl terminal group and a vinyl internal branching unit.

[0013] Preferably, the hyperbranched poly(urethane-amine) having hydroxyl end groups and vinyl internal branching units is prepared according to the method of Example 1 in the Chinese invention patent with authorization announcement number CN106519158B.

[0014] Preferably, the photoinitiator is a mixture of a triarylsulfonium salt photoinitiator and benzoin ethyl ether in a mass ratio of (1-3):1.

[0015] Preferably, the triarylsulfonium salt photoinitiator is Easepi 6992 cationic photoinitiator.

[0016] Another object of the present invention is to provide a method for preparing the delayed curing UV adhesive, comprising the following steps:

[0017] Step S1, mixing bisphenol A epoxy resin and naphthalene epoxy resin by weight, heating and stirring evenly, and cooling to room temperature to obtain a resin mixture;

[0018] Step S2, adding a photocurable resin to the resin mixture prepared in step S1, mixing evenly, then adding a photoinitiator, and continuing to mix evenly.

[0019] Preferably, the temperature of the heating and stirring in step S1 is 75-90°C.

[0020] Preferably, in step S2, vacuum degassing treatment is performed before adding the photoinitiator. DETAILED DESCRIPTION

[0021] The invention provides a delayed curing UV adhesive, which comprises the following components in parts by weight: 50-80 parts of bisphenol A epoxy resin, 1-10 parts of naphthalene epoxy resin, 5-10 parts of photocurable resin and 1-5 parts of photoinitiator.

[0022] Preferably, the bisphenol A epoxy resin has an epoxy equivalent of 175 to 200 g / mol.

[0023] Preferably, the bisphenol A epoxy resin is an epoxy resin with the trade name of E54 or 0164, which is provided by Nantong Xingchen Synthetic Materials Co., Ltd.

[0024] Preferably, the naphthalene ring epoxy resin is a naphthyl difunctional epoxy resin, and the epoxy value is 0.65-0.73 equivalent / 100g.

[0025] Preferably, the naphthalene ring epoxy resin is EBA-65 naphthalene type epoxy resin, which is provided by Shanghai Huayi Resin Co., Ltd.

[0026] Preferably, the photocurable resin is a hyperbranched poly(urethane-amine) having a hydroxyl terminal group and a vinyl internal branching unit.

[0027] Preferably, the hyperbranched poly(urethane-amine) having hydroxyl end groups and vinyl internal branching units is prepared according to the method of Example 1 in the Chinese invention patent with authorization announcement number CN106519158B.

[0028] Preferably, the photoinitiator is a mixture of a triarylsulfonium salt photoinitiator and benzoin ethyl ether in a mass ratio of (1-3):1.

[0029] Preferably, the triarylsulfonium salt photoinitiator is Easepi 6992 cationic photoinitiator.

[0030] Another object of the present invention is to provide a method for preparing the delayed curing UV adhesive, comprising the following steps:

[0031] Step S1, mixing bisphenol A epoxy resin and naphthalene epoxy resin by weight, heating and stirring evenly, and cooling to room temperature to obtain a resin mixture;

[0032] Step S2, adding a photocurable resin to the resin mixture prepared in step S1, mixing evenly, then adding a photoinitiator, and continuing to mix evenly.

[0033] Preferably, the temperature of the heating and stirring in step S1 is 75-90°C.

[0034] Preferably, in step S2, vacuum degassing treatment is performed before adding the photoinitiator.

[0035] Due to the application of the above technical scheme, the patent of the present invention has the following advantages compared with the prior art: the delayed curing UV glue provided by the present invention is made of the following components in parts by weight: 50-80 parts of bisphenol A epoxy resin, 1-10 parts of naphthalene epoxy resin, 5-10 parts of photocurable resin, and 1-5 parts of photoinitiator; through the reasonable selection of the composition formula, the prepared UV glue can achieve delayed curing, and the mechanical properties of the cured UV glue are excellent.

[0036] In order to enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only embodiments of a part of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained under the premise of equivalent changes and modifications made by ordinary technicians in the field should belong to the scope of protection of the present invention.

[0037] Example 1

[0038] A delayed curing UV adhesive comprises the following components in parts by weight: 50 parts of bisphenol A epoxy resin, 1 part of naphthalene epoxy resin, 5 parts of photocurable resin and 1 part of photoinitiator.

[0039] The bisphenol A epoxy resin is an epoxy resin with a trade name of E54, provided by Nantong Xingchen Synthetic Materials Co., Ltd.; the naphthalene ring epoxy resin is EBA-65 naphthalene-type epoxy resin, provided by Shanghai Huayi Resin Co., Ltd.; the photocurable resin is a hyperbranched poly(urethane-amine) with a hydroxyl terminal group and a vinyl internal branching unit; the hyperbranched poly(urethane-amine) with a hydroxyl terminal group and a vinyl internal branching unit is prepared according to the method of Example 1 in the Chinese invention patent with authorization announcement number CN106519158B; the photoinitiator is a triarylsulfonium salt photoinitiator and benzoin ethyl ether mixed in a mass ratio of 1:1; the triarylsulfonium salt photoinitiator is Easepi 6992 cationic photoinitiator.

[0040] A method for preparing the delayed curing UV adhesive comprises the following steps:

[0041] Step S1, mixing bisphenol A epoxy resin and naphthalene epoxy resin by weight, heating and stirring evenly, cooling to room temperature, to obtain a resin mixture; the heating and stirring temperature in step S1 is 75° C.;

[0042] Step S2, adding the photocurable resin to the resin mixture prepared in step S1, mixing evenly, then adding the photoinitiator, and continuing to mix evenly; in step S2, vacuum degassing treatment is also performed before adding the photoinitiator.

[0043] Example 2

[0044] This example provides a delayed curing UV adhesive and a preparation method thereof, which is basically the same as Example 1, except that it includes the following components in parts by weight: 60 parts of bisphenol A epoxy resin, 3 parts of naphthalene epoxy resin, 6 parts of photocurable resin, and 2 parts of photoinitiator; the photoinitiator is a mixture of triarylsulfonium salt photoinitiator and benzoin ethyl ether in a mass ratio of 1.5:1; the heating and stirring temperature in step S1 is 79°C.

[0045] Example 3

[0046] This example provides a delayed curing UV adhesive and a preparation method thereof, which is basically the same as Example 1, except that it includes the following components in parts by weight: 65 parts of bisphenol A epoxy resin, 6 parts of naphthalene epoxy resin, 7 parts of photocurable resin, and 3 parts of photoinitiator; the photoinitiator is a mixture of triarylsulfonium salt photoinitiator and benzoin ethyl ether in a mass ratio of 2:1; the heating and stirring temperature in step S1 is 82°C.

[0047] Example 4

[0048] This example provides a delayed curing UV adhesive and a preparation method thereof, which is basically the same as Example 1, except that it includes the following components in parts by weight: 75 parts of bisphenol A epoxy resin, 8 parts of naphthalene epoxy resin, 9 parts of photocurable resin, and 4 parts of photoinitiator; the photoinitiator is a mixture of triarylsulfonium salt photoinitiator and benzoin ethyl ether in a mass ratio of 2.5:1; the heating and stirring temperature in step S1 is 87°C.

[0049] Example 5

[0050] This example provides a delayed curing UV adhesive and a preparation method thereof, which is basically the same as Example 1, except that it includes the following components in parts by weight: 80 parts of bisphenol A epoxy resin, 10 parts of naphthalene epoxy resin, 10 parts of photocurable resin, and 5 parts of photoinitiator; the photoinitiator is a mixture of triarylsulfonium salt photoinitiator and benzoin ethyl ether in a mass ratio of 3:1; the heating and stirring temperature in step S1 is 90°C.

[0051] Comparative Example 1

[0052] This example provides a delayed curing UV adhesive and a preparation method thereof, which is basically the same as Example 1, except that an equal amount of bisphenol A epoxy resin is used instead of naphthalene epoxy resin.

[0053] Comparative Example 2

[0054] This example provides a delayed curing UV adhesive and a preparation method thereof, which is basically the same as Example 1, except that an equal amount of bisphenol A epoxy resin is used instead of the photocurable resin.

[0055] When testing the bonding strength of the delayed curing UV adhesive of the present invention, the material selected is PC / PC, 405nm UV light, 350mW energy is irradiated for 6 seconds, and the average shear force and other mechanical properties are measured after 24 hours, and the curing time is statistically calculated. The test results are shown in Table 1.

[0056] Table 1

[0057] project Average shear force after 24h Tensile Strength Curing time unit MPa MPa — Example 1 26.3 52.1 8 minutes 10 seconds Example 2 27.0 53.4 8 minutes 40 seconds Example 3 28.1 54.9 9 minutes 3 seconds Example 4 28.6 55.6 9 minutes 40 seconds Example 5 29.4 56.6 9 minutes 58 seconds Comparative Example 1 22.5 47.3 7 minutes 25 seconds Comparative Example 2 23.7 48.9 7 minutes 32 seconds

[0058] As can be seen from Table 1, the delayed curing UV adhesive involved in the embodiment of the present invention has better delayed curing performance and mechanical properties after curing than the comparative example product, and the combined use of naphthalene epoxy resin and light-curing resin has a beneficial effect on improving the above properties.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. At the same time, the above description should be understandable and implementable for those with ordinary knowledge in the relevant technical field. Therefore, other equivalent changes or modifications that do not deviate from the concepts disclosed in the present invention should be included in the scope of protection of the present invention.

Claims

1. A delayed curing UV adhesive, characterized in that: The invention comprises the following components in parts by weight: 50-80 parts of bisphenol A epoxy resin, 1-10 parts of naphthalene epoxy resin, 5-10 parts of photocurable resin and 1-5 parts of photoinitiator.

2. The delayed curing UV adhesive according to claim 1, characterized in that: The epoxy equivalent of the bisphenol A epoxy resin is 175-200 g / mol.

3. The delayed curing UV adhesive according to claim 1, characterized in that: The bisphenol A epoxy resin is an epoxy resin with a trade name of E54 or 0164.

4. The delayed curing UV adhesive according to claim 1, characterized in that: The naphthalene ring epoxy resin is a naphthyl difunctional epoxy resin, and the epoxy value is 0.65-0.73 equivalent / 100g.

5. The delayed curing UV adhesive according to claim 1, characterized in that: The naphthalene ring epoxy resin is EBA-65 naphthalene type epoxy resin.

6. The delayed curing UV adhesive according to claim 1, characterized in that: The photocurable resin is a hyperbranched poly(urethane-amine) having a hydroxyl terminal group and a vinyl internal branching unit.

7. The delayed curing UV adhesive according to claim 1, characterized in that: The photoinitiator is a mixture of a triarylsulfonium salt photoinitiator and benzoin ethyl ether in a mass ratio of (1-3):

1.

8. The delayed curing UV adhesive according to claim 7, characterized in that: The triarylsulfonium salt photoinitiator is Easepi 6992 cationic photoinitiator.

9. A method for preparing the delayed curing UV adhesive according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step S1, mixing bisphenol A epoxy resin and naphthalene epoxy resin by weight, heating and stirring evenly, and cooling to room temperature to obtain a resin mixture; Step S2, adding a photocurable resin to the resin mixture prepared in step S1, mixing evenly, then adding a photoinitiator, and continuing to mix evenly.

10. The method for preparing the delayed curing UV adhesive according to claim 9, characterized in that: The heating and stirring temperature in step S1 is 75-90° C.; and vacuum degassing treatment is also performed before adding the photoinitiator in step S2.