Low-viscosity free radical cation dual-curing optical fiber ring pouring sealant applied to thin optical fiber and preparation method of low-viscosity free radical cation dual-curing optical fiber ring pouring sealant

Abstract

The invention relates to a low-viscosity free radical cation dual-curing optical fiber ring pouring sealant applied to thin optical fibers and a preparation method thereof. The invention discloses an optical fiber ring pouring sealant composition which is characterized by comprising the following components in percentage by weight: 50-60% of epoxy resin, 10-20% of epoxy acrylate oligomer, 5-10% of acrylate monomer, 5-10% of vinyl ether monomer, 5-10% of oxetane monomer, 5-10% of free radical photoinitiator, 5-10% of cationic initiator and 5-10% of assistant. The optical fiber ring potting material comprises the following components in percentage by weight: 5-30% of an epoxy acrylate oligomer, 5-30% of an acrylate monomer, 5-30% of a vinyl ether monomer, 1-10% of an oxetane monomer, 0.5-5% of a free radical photoinitiator, 0.01-2% of a cationic initiator and 0.01-1% of an assistant.The prepared optical fiber ring potting material has the characteristic of low viscosity, the viscosity of the optical fiber ring potting material is smaller than 400 cps, and the optical fiber ring potting material can be UV-cured and can be used as an optical fiber ring potting material. And the part which is not exposed to light can be slowly self-cured at normal temperature without heating and curing.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and particularly relates to a low-viscosity free radical-cation dual-curing optical fiber loop potting adhesive for thin optical fibers and a preparation method thereof. Background Art

[0002] The preparation technology of the optical fiber loop is mainly the winding of the optical fiber loop. The winding of the optical fiber loop is mainly completed by a precision winding machine. However, after the winding of the optical fiber loop is completed, the optical fiber forms a multi-layer tightly arranged ring body with very small gaps, which brings great difficulties to the potting work. If the potting is not thorough and the optical fiber loop is not completely impregnated with glue, the final accuracy of the fiber optic gyroscope will be affected.

[0003] This poses relatively special requirements for the potting adhesive for the optical fiber loop. First, due to the design geometric principle, the optical fiber loop cannot be completely transparent, and single free radical curing cannot meet the use requirements. And the curing speed of pure epoxy resin cation is slow, it cannot be quickly positioned, and air bubbles will enter during the mixing process, affecting the accuracy of the optical fiber loop.

[0004] At present, the UV light-curing optical fiber loop potting adhesives applied on the market are all free radical-curing potting adhesives, which have too high viscosity and cannot penetrate into the tiny gaps inside the optical fiber loop, and it is difficult to remove air bubbles during the potting process. Especially when applied to thin optical fibers with an inner diameter of 60 microns, the problem is particularly obvious. Due to a large number of air bubbles that cannot escape, the performance of the optical fiber loop is unstable and cracking problems are likely to occur. In addition, the UV-thermal dual-curing potting adhesives on the market will affect the optical fiber structure and thus the accuracy of the optical fiber loop during the curing heating process. Therefore, there is an urgent need to invent a low-viscosity free radical-cation dual-photo-curing optical fiber loop potting adhesive that is more suitable for thin optical fibers to meet the use requirements. Summary of the Invention

[0005] According to the above existing technical problems, the present invention provides a low-viscosity free radical-cation dual-curing optical fiber loop potting adhesive for thin optical fibers and a preparation method thereof.

[0006] To achieve the above object, the technical solution of the present invention is as follows: In the first aspect of the present application, a low-viscosity free-radical cation dual-curing optical fiber loop potting adhesive for thin optical fibers is provided, characterized in that the composition of the optical fiber loop potting adhesive comprises epoxy resin, epoxy acrylate oligomer, acrylate monomer, vinyl ether monomer, oxetane monomer, free-radical photoinitiator, cationic initiator, and additives. Based on the weight of the potting adhesive composition, the epoxy resin is 50-60%, the epoxy acrylate oligomer is 5-30%, the acrylate monomer is 5-30%, the vinyl ether monomer is 5-30%, the oxetane monomer is 1-10%, the free-radical photoinitiator is 0.5-5%, the cationic initiator is 0.01-2%, and the additives are 0.01-1%.

[0007] Preferably, the epoxy resin is one or any combination of bisphenol A epoxy resin, 3,4-epoxycyclohexylmethyl 3',4'-epoxycyclohexanecarboxylate, bis((3,4-epoxycyclohexyl)methyl) adipate, 3,4-epoxycyclohexylmethyl methacrylate.

[0008] Preferably, the epoxy acrylate oligomer is bisphenol A type epoxy acrylate oligomer.

[0009] Preferably, the acrylate monomer is any one of monofunctional acrylate monomers such as 2-hydroxyethyl methacrylate, 1,6-hexanediol diacrylate, ethoxyethoxyethyl acrylate, tetrahydrofurfuryl acrylate, trimethylolpropane triacrylate.

[0010] Preferably, the vinyl ether monomer is one or any combination of 4-hydroxybutyl vinyl ether, triethylene glycol divinyl ether, diethylene glycol divinyl ether, divinyl-1,4-butanediol ether, 2-ethylhexyl vinyl ether, ethylene glycol vinyl ether.

[0011] Preferably, the oxetane monomer is any one of 1,3-epoxypropane, 3-hydroxymethyl-3-ethyloxetane, 2-(3-oxetanyl)-1-butanol.

[0012] Preferably, the free-radical photoinitiator is any one or a combination of two of free-radical photoinitiator 184, TPO, ITX.

[0013] Preferably, the cationic initiator is any one of diaryliodonium salts, triarylsulfonium salts.

[0014] Preferably, the additive is a polymerization inhibitor, and the purpose is to extend the storage time of the formulation and prevent self-polymerization reaction.

[0015] Preferably, the additive is one or any combination of 2-phenylethoxy acrylate, p-methoxyphenol, hydroquinone.

[0016] The second aspect of the present application provides a preparation method of a low-viscosity free radical cation dual-curing optical fiber loop potting adhesive for thin optical fibers, and the specific steps are as follows: Step a, pre-dissolve a free radical photoinitiator in an acrylate monomer to obtain a premix; Step b, put an epoxy acrylate oligomer, an epoxy resin, the premix obtained in step a, and an inhibitor into a reaction kettle, and stir at 60-80 °C for 1-2 h; Step c, after the stirring is completed, cool down to below 30 degrees, add a vinyl ether monomer and an oxetane monomer and then stir. After stirring evenly, add a cation initiator and stir evenly. Finally, filter tightly through a 0.5 µm filter screen to obtain a product.

[0017] Advantages of the present invention: The optical fiber loop potting material prepared by the present invention has the characteristic of low viscosity, and its viscosity is less than 400 cps. And it is cured by UV curing during curing, and heating is not required for curing. And after light curing, the parts that are not exposed to light can also be slowly self-cured at room temperature to achieve complete curing, solving the problem that heat curing will affect the optical fiber structure and thus affect the accuracy of the optical fiber loop; The optical fiber loop potting material prepared by the present invention has a small shrinkage rate after curing, and also has the advantages of high tensile strength after curing and no cracking after high and low temperature cycling, and is more suitable for the winding and potting of thin optical fiber loops. Description of the drawings

[0018] Figure 1 It is a schematic diagram of the test results of the samples obtained in the embodiments of the present invention. Specific embodiments

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] Example 1

[0021] The composition of the optical fiber loop potting adhesive is: 70% of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, 10% of epoxy acrylate oligomer, 5% of 1,6-hexanediol diacrylate, 8.23% of diethylene glycol divinyl ether, 3% of 1,3-epoxypropane, 0.5% of free radical initiator TPO, 3% of diaryliodonium salt, and 0.02% of p-methoxyphenol.

[0022] Preparation of optical fiber loop potting adhesive: Step a: Pre-dissolve the radical initiator TPO in 1,6 - hexanediol diacrylate to obtain a premix. Step b: Put the epoxy acrylate oligomer, 3,4 - epoxycyclohexylmethyl 3',4' - epoxycyclohexanecarboxylate, the premix obtained in step a, and p - methoxyphenol into a reaction kettle, and stir at 60 - 80 °C for 1 - 2 h. Step c: After stirring, cool down the temperature to below 30 °C, add diethylene glycol divinyl ether and 1,3 - epoxypropane and then stir. After stirring evenly, add diaryliodonium salt and stir evenly. Finally, filter tightly through a 0.5 - µm filter screen to obtain the product.

[0023] Example 2

[0024] The composition of the optical fiber loop potting adhesive is: 3,4 - epoxycyclohexylmethyl 3',4' - epoxycyclohexanecarboxylate 60%, epoxy acrylate oligomer 15%, 1,6 - hexanediol diacrylate 8.23%, diethylene glycol divinyl ether 9%, 1,3 - epoxypropane 3%, radical photoinitiator TPO 0.5%, diaryliodonium salt 3%, p - methoxyphenol 0.02%.

[0025] Preparation of optical fiber loop potting adhesive: Step a: Pre - dissolve the radical initiator TPO in 1,6 - hexanediol diacrylate to obtain a premix. Step b: Put the epoxy acrylate oligomer, 3,4 - epoxycyclohexylmethyl 3',4' - epoxycyclohexanecarboxylate, the premix obtained in step a, and p - methoxyphenol into a reaction kettle, and stir at 60 - 80 °C for 1 - 2 h. Step c: After stirring, cool down the temperature to below 30 °C, add diethylene glycol divinyl ether and 1,3 - epoxypropane and then stir. After stirring evenly, add diaryliodonium salt and stir evenly. Finally, filter tightly through a 0.5 - µm filter screen to obtain the product.

[0026] Example 3

[0027] The composition of the optical fiber loop potting adhesive is: 3,4 - epoxycyclohexylmethyl 3',4' - epoxycyclohexanecarboxylate 55%, epoxy acrylate oligomer 15%, 1,6 - hexanediol diacrylate 13.73%, diethylene glycol divinyl ether 9%, 1,3 - epoxypropane 3%, radical photoinitiator 184 1%, diaryliodonium salt 3%, p - methoxyphenol 0.02%.

[0028] Preparation of optical fiber loop potting adhesive: Step a: Pre - dissolve the free - radical initiator TPO in 1,6 - hexanediol diacrylate to obtain a premix. Step b: Put the epoxy acrylate oligomer, 3,4 - epoxycyclohexylmethyl 3',4' - epoxycyclohexanecarboxylate, the premix obtained in step a, and p - methoxyphenol into a reaction kettle, and stir for 1 - 2 h under the condition of 60 - 80 °C. Step c: After stirring, cool down the temperature to below 30 °C, add diethylene glycol divinyl ether and 1,3 - epoxypropane and then stir. After stirring evenly, add diaryliodonium salt and stir evenly. Finally, filter tightly through a 0.5 - µm filter to obtain the product.

[0029] Example 4

[0030] The composition of the optical fiber loop potting adhesive is: 3,4 - epoxycyclohexylmethyl 3',4' - epoxycyclohexanecarboxylate 50%, epoxy acrylate oligomer 20%, 1,6 - hexanediol diacrylate 13.73%, diethylene glycol divinyl ether 9%, 1,3 - epoxypropane 3%, free - radical photo - initiator 184 1%, diaryliodonium salt 3%, p - methoxyphenol 0.02%.

[0031] Preparation of the optical fiber loop potting adhesive: Step a: Pre - dissolve the free - radical initiator TPO in 1,6 - hexanediol diacrylate to obtain a premix. Step b: Put the epoxy acrylate oligomer, 3,4 - epoxycyclohexylmethyl 3',4' - epoxycyclohexanecarboxylate, the premix obtained in step a, and p - methoxyphenol into a reaction kettle, and stir for 1 - 2 h under the condition of 60 - 80 °C. Step c: After stirring, cool down the temperature to below 30 °C, add diethylene glycol divinyl ether and 1,3 - epoxypropane and then stir. After stirring evenly, add diaryliodonium salt and stir evenly. Finally, filter tightly through a 0.5 - µm filter to obtain the product.

[0032] Example 5

[0033] The difference between this example and Example 1 is that 3,4 - epoxycyclohexylmethyl 3',4' - epoxycyclohexanecarboxylate is replaced with bisphenol A epoxy resin in equal mass, and other parameters and conditions are exactly the same as those in Example 1.

[0034] Example 6

[0035] The difference between this example and Example 1 is that an equal mass of 1,6 - hexanediol diacrylate is replaced with trimethylolpropane triacrylate, and other parameters and conditions are exactly the same as those in Example 1.

[0036] Example 7

[0037] The difference between this example and Example 1 is that an equal mass of diethylene glycol divinyl ether is replaced with 4 - hydroxybutyl vinyl ether, and other parameters and conditions are exactly the same as those in Example 1.

[0038] Example 8

[0039] The difference between this example and Example 1 is that an equal mass of the free - radical photo - initiator TPO is replaced with photo - initiator ITX, and other parameters and conditions are exactly the same as those in Example 1.

[0040] Comparative Example 1 The difference between this comparative example and Example 1 is that an equal mass of epoxy acrylate oligomer and tetrahydrofuran acrylate is replaced with 3,4 - epoxycyclohexylmethyl 3',4' - epoxycyclohexanecarboxylate, and other parameters and conditions are exactly the same as those in Example 1.

[0041] Comparative Example 2 The difference between this comparative example and Example 1 is that an equal mass of 3,4 - epoxycyclohexylmethyl 3',4' - epoxycyclohexanecarboxylate is replaced with epoxy acrylate, an equal mass of diethylene glycol divinyl ether is replaced with tetrahydrofuran acrylate, and an equal mass of diaryliodonium salt is replaced with photo - initiator 184, and other parameters and conditions are exactly the same as those in Example 1.

[0042] Next, performance tests are carried out on the samples of the potting adhesives prepared in each example, and the test results are shown in the table.

[0043] It should be noted that the process of the performance test is as follows: Viscosity test method: GB / T 10247.4 Sample preparation: A mold with a length of 10 cm, a width of 2 cm, and a depth of 2 cm is made, and the prepared potting adhesive is poured into the mold. After vacuum degassing, it is cured in the following several ways respectively.

[0044] 1. Place the mold and cure it by irradiation with a high - pressure mercury lamp. The light intensity is 1000 mW / cm2, and the time is 20 seconds. 2. Place the mold at room temperature for 72 h for post - curing.

[0045] Shrinkage rate test: The shrinkage rate of the sample after complete curing is measured respectively. Uncured material test: Take out the cured sample and observe whether there is uncured glue.

[0046] Tensile strength and elongation test: After UV curing with a light intensity of 1000 mW / cm2 and allowing the sample bars to stand at room temperature for 72 h, tensile standard sample bars were made and tested. The experimental results are expressed as the arithmetic mean of the tensile strength.

[0047] Drop test: The cured samples were subjected to thermal shock (first placed in an 85°C environment for 0.5 h, then immediately placed in a -40°C environment for 0.5 h, which is one cycle). After 500 cycles, the samples were placed in a drum drop tester, with a drop height of 1000 mm, a drop speed of 20 times per minute, and dropped 200 times. Observe whether there are any cracking phenomena in the samples.

[0048] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A low-viscosity free radical cation dual-curing optical fiber loop potting adhesive applied to thin optical fibers, characterized in that The composition of the optical fiber loop potting adhesive contains epoxy resin, epoxy acrylate oligomer, acrylate monomer, vinyl ether monomer, oxetane monomer, free radical photoinitiator, cationic initiator and additives. Based on the weight of the potting adhesive composition, the epoxy resin is 50 - 60%, the epoxy acrylate oligomer is 5 - 30%, the acrylate monomer is 5 - 30%, the vinyl ether monomer is 5 - 30%, the oxetane monomer is 1 - 10%, the free radical photoinitiator is 0.5 - 5%, the cationic initiator is 0.01 - 2%, and the additives are 0.01 - 1%.

2. The low-viscosity free radical cation dual-curing optical fiber loop potting adhesive for thin optical fibers according to claim 1, wherein The epoxy resin is one or any combination of bisphenol A epoxy resin, 3,4-epoxycyclohexylmethyl 3',4'-epoxycyclohexanecarboxylate, bis((3,4-epoxycyclohexyl)methyl) adipate, and 3,4-epoxycyclohexylmethyl methacrylate.

3. The low-viscosity free radical cation dual-curing optical fiber loop potting adhesive applied to thin optical fibers according to claim 1 is characterized in that The epoxy acrylate oligomer is bisphenol A type epoxy acrylate oligomer.

4. A low-viscosity free radical cation dual-curing optical fiber loop potting adhesive applied to thin optical fibers according to claim 1, characterized in that The acrylate monomer is any one of monofunctional acrylate monomers such as 2-hydroxyethyl methacrylate, 1,6-hexanediol diacrylate, ethoxyethoxyethyl acrylate, tetrahydrofuran acrylate, and trimethylolpropane triacrylate.

5. The low-viscosity free radical cation dual-curing optical fiber loop potting adhesive applied to thin optical fibers according to claim 1, wherein The vinyl ether monomer is one or any combination of 4-hydroxybutyl vinyl ether, triethylene glycol divinyl ether, diethylene glycol divinyl ether, divinyl-1,4-butanediol ether, 2-ethylhexyl vinyl ether, and vinyl ethylene glycol ether.

6. The low-viscosity free radical cation dual-curing optical fiber loop potting adhesive applied to thin optical fibers according to claim 1, characterized in that The oxetane monomer is any one of 1,3-epoxypropane, 3-hydroxymethyl-3-ethyloxetane, and 2-(3-oxetanyl)-1-butanol.

7. A low-viscosity free radical cation dual-curing optical fiber loop potting adhesive for thin optical fibers according to claim 1, characterized in that The cationic initiator is any one of diaryliodonium salts and triarylsulfonium salts.

8. The low-viscosity free radical cation dual-curing optical fiber loop potting adhesive applied to thin optical fibers according to claim 1, wherein The additive is a polymerization inhibitor.

9. A low-viscosity free radical cation dual-curing optical fiber loop potting adhesive for thin optical fibers according to claim 8, characterized in that The additive is one or any combination of 2-phenylethoxy acrylate, p-methoxyphenol, and hydroquinone.

10. The preparation method of a low-viscosity free radical cation dual-curing optical fiber loop potting adhesive applied to thin optical fibers according to any one of claims 1 - 9 is as follows: Step a: Pre-dissolve the free radical photoinitiator in the acrylate monomer to obtain a premix. Step b: Put the epoxy acrylate oligomer, epoxy resin, the premix obtained in step a, and the polymerization inhibitor into a reaction kettle, and stir at 60 - 80 °C for 1 - 2 h. Step c: After the stirring is completed, cool down the temperature. When the temperature is lowered below 30 °C, add the vinyl ether monomer and the oxetane monomer and then stir. After stirring evenly, add the cationic initiator and stir evenly. Finally, filter tightly through a 0.5 µm filter screen to obtain the product.

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