UV low-energy fast-curing wire harness sealant

Abstract

The invention relates to a UV (ultraviolet) low-energy fast-curing wire harness sealant, which adopts polyurethane acrylic resin as main resin, and is compounded with fast-curing bifunctional or trifunctional polyurethane acrylic resin and a surface-drying and deep-curing photo-initiation system. The invention aims to solve the problems of non-uniform curing, surface stickiness, insufficient adhesion to difficult-to-adhere base materials such as PA and the like of the existing UV glue under a low-energy curing condition. The sealant formula also comprises an acrylic monomer used for improving the adhesive force, adjusting the viscosity and improving the fluidity, and an auxiliary agent used for providing thixotropy and developing recognition. Through the UV LED curing technology, rapid curing can be achieved under the conditions of low illumination intensity and short irradiation time, so that the production efficiency is improved, the energy consumption is reduced, and the curing quality is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of sealants, and in particular to a UV low-energy fast-curing wire harness sealant. Background Technology

[0002] In modern industry, particularly in automotive electronics, consumer electronics, and industrial automation, the sealing of electronic wire harnesses and connectors is crucial for ensuring the long-term stable operation of equipment. To meet the stringent sealing requirements of these industries, wire harness sealants, as an important sealing material, are widely used for the protection and fixation of electronic components. However, existing wire harness sealant technologies still suffer from several problems, severely impacting their application under high-efficiency production and high-performance requirements.

[0003] Traditional thermosetting wire harness sealants typically require prolonged heating to complete the curing process. While this process provides stable curing results, its slow curing speed leads to low production efficiency and fails to meet the demands of modern large-scale production for rapid curing. Furthermore, the high temperatures used in thermosetting increase energy consumption and can adversely affect sensitive materials such as plastics and rubber, thereby reducing their physical properties and limiting the widespread application of thermosetting adhesives.

[0004] In comparison, while UV-curable wire harness sealants have addressed the slow curing speed issue to some extent, existing UV-curable adhesives still suffer from problems such as uneven curing, surface stickiness, and insufficient adhesion to materials like nylon. Traditional UV-curable adhesives often require high-intensity UV irradiation or prolonged exposure to light to achieve complete curing, which increases production costs, extends production cycles, and consumes excessive energy.

[0005] Another common problem is the difficulty in achieving both surface drying and deep curing during the curing process. While UV adhesives with faster surface drying have better surface curing effects, they often suffer from insufficient deep curing and inadequate curing depth under lower curing energy conditions. On the other hand, formulations with slower overall curing speeds are more susceptible to oxygen inhibition, leading to sticky surfaces or incomplete surface curing, which affects the application effect and the final product appearance.

[0006] The adhesion of nylon terminals has been a long-standing challenge in existing technologies. Nylon, being a material with low surface energy and high strength, is difficult to bond with adequately when using conventional adhesives without additional surface treatment. Therefore, existing UV-cured adhesives often require the addition of large amounts of adhesion monomers or additional surface treatments, which not only increases production costs but also leads to unstable product performance and reduces the reliability of the adhesive in practical applications.

[0007] Furthermore, existing UV-curable adhesives typically require high light energy (e.g., 1000 mJ / cm²) for curing. 2 The above-mentioned ultraviolet light energy) requires high energy, which increases production costs and fails to effectively solve the problem of low energy efficiency. Especially in the context of the increasing demand for energy conservation, emission reduction and environmental protection in modern manufacturing, the high energy consumption of traditional adhesives is particularly unsuitable.

[0008] In summary, existing wire harness sealants suffer from significant shortcomings in terms of curing speed, adhesion, environmental friendliness, and production efficiency. These issues not only affect their performance in complex and demanding applications but also limit their widespread use in large-scale production. Therefore, there is an urgent need for a novel wire harness sealant that can solve these problems in existing technologies and meet the demands of modern industry for efficient, stable, and environmentally friendly materials. Summary of the Invention

[0009] In view of the above analysis, the present invention aims to provide a UV low-energy fast-curing wire harness sealant to solve the problems in the prior art.

[0010] The objective of this invention is mainly achieved through the following technical solutions:

[0011] A UV low-energy fast-curing wire harness sealant, comprising the following components:

[0012] The main resin is polyurethane acrylic resin, which has excellent adhesion to nylon terminals;

[0013] At least one surface-drying photoinitiator is used to inhibit oxygen inhibition and improve surface drying effect;

[0014] At least one deep-curing photoinitiator is used to achieve deep curing of the adhesive layer;

[0015] Acrylic monomers are used to improve adhesion, adjust viscosity, and improve flowability.

[0016] At least one additive is used to improve the adhesion, flowability and curing properties of the adhesive.

[0017] In one or more embodiments, the main resin is a polyurethane acrylic resin, specifically DR-U249, with a mass ratio of 70-80 parts.

[0018] In one or more embodiments, the proportion of polyurethane acrylate resin in the main resin is 70-80 parts, and at least one fast-curing bifunctional or trifunctional polyurethane acrylate resin, specifically SW8801 or L8401, is added, accounting for 20-30 parts by mass.

[0019] In one or more embodiments, the photoinitiator is a surface-drying photoinitiator, preferably a photoinitiator that can inhibit oxygen inhibition polymerization, specifically one or at least two of MBF, 184, 1173, and 651, preferably containing MBF, with a mass ratio of 5 to 7 parts, for improving the surface curing effect.

[0020] In one or more embodiments, the deep curing photoinitiator may be one or more of TMO, TPO-L, and 819, with a mass ratio of 3 to 5 parts, for achieving deep curing of the adhesive layer.

[0021] In one or more embodiments, the acrylic monomers are IBOA and DMAA, or at least one of ACMO and TMCHA replaces IBOA with equivalent functionality; the monomers are used to improve adhesion, adjust viscosity and improve flowability.

[0022] In one or more embodiments, the additive is a silane coupling agent, specifically KH-570, at a mass ratio of 1 to 3 parts, used to enhance the adhesion between the adhesive and the nylon substrate.

[0023] In one or more embodiments, the fumed silica in the wire harness sealant is R202, accounting for 5 to 8 parts by mass, used to provide thixotropy and reduce system flowability.

[0024] In one or more embodiments, the fluorescent agent in the wire harness sealant is OB, with a mass ratio of 0.1 to 0.3 parts, used to provide color recognition during the dispensing process.

[0025] In one or more embodiments, the curing conditions for the wire harness sealant are an LED 365nm light source, a curing light intensity of 200~300mW / cm², and an irradiation time of 3~5 seconds.

[0026] The technical solution of this invention can achieve at least one of the following effects:

[0027] The UV low-energy fast-curing wire harness sealant of this invention solves the technical problems of slow curing speed, susceptibility to oxygen inhibition leading to surface stickiness, and insufficient adhesion to difficult-to-bond substrates such as PA under low-energy UV curing conditions through the synergistic design of resin compounding and surface drying and deep curing photoinitiation systems. This sealant uses polyurethane acrylic resin (such as DR-U249) as the main resin, which imparts excellent flexibility and adhesion to nylon terminals; and by compounding with fast-curing bifunctional or trifunctional polyurethane acrylic resins (such as SW8801 or L8401), it balances fast curing speed with good mechanical properties.

[0028] The sealant of this invention can achieve a strength of less than 1000 mJ / cm 2 Under ultraviolet LED light source, through 200~300mW / cm2 The light intensity allows for rapid curing within 3-5 seconds. This curing condition not only improves production efficiency and shortens curing time, but also achieves both surface drying and deep curing effects with lower energy consumption, solving the problem that traditional UV adhesives require higher light intensity or longer irradiation time to obtain sufficient curing depth.

[0029] This invention also has broad applicability, effectively adapting to various substrates such as PVC, PBT, and PI, and providing excellent adhesion, particularly to nylon terminals. This characteristic enables the wire harness sealant of this invention to be widely used in industries such as automotive and consumer electronics, meeting the encapsulation needs of different products and providing efficient and reliable sealing protection.

[0030] Furthermore, the use of UVLED curing technology not only reduces energy consumption and waste compared to traditional thermal curing processes, but also avoids harmful gases that may be generated during baking, meeting modern environmental protection requirements. The low energy consumption of the UVLED curing process gives the products of this invention significant advantages in reducing production costs, improving production efficiency, and reducing environmental pollution.

[0031] In summary, the UV low-energy fast-curing wire harness sealant of the present invention has significant technical advantages in achieving rapid curing, improving adhesion to difficult-to-bond substrates such as PA, optimizing the balance between surface drying and deep curing, and reducing production energy consumption. It solves many problems in the prior art and has broad application prospects and high market competitiveness.

[0032] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0033] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0034] Figure 1 This is a schematic diagram of the preparation process of the present invention. Detailed Implementation

[0035] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0036] The technical solution of the present invention will be further described below with reference to specific embodiments. However, the present invention should not be limited to these embodiments. Unless specifically stated otherwise, all features can be replaced by other equivalent or similar features. Unless specifically stated otherwise, each feature is only one example of a series of equivalent or similar features. The terminology used in the present invention, unless otherwise stated, generally has the meaning commonly understood by those skilled in the art. In the following embodiments, unless otherwise stated, concentration % refers to mass percentage; all substances used are commercially available.

[0037] Figure 1 This is a schematic diagram of the preparation process of the UV low-energy rapid curing wire harness sealant of the present invention.

[0038] Example 1

[0039] UV low-energy fast-curing wire harness sealants include:

[0040] Polyurethane acrylic resin DR-U249: 75 parts

[0041] Fast-curing bifunctional polyurethane acrylic resin SW8801: 25 parts

[0042] Thiol-modified polyurethane acrylic resin LED01: 18 parts

[0043] Acrylic monomer IBOA: 50 parts

[0044] Acrylic monomer DMAA: 30 parts

[0045] Silane coupling agent KH570: 2 parts

[0046] Surface-drying photoinitiator MBF: 5 parts

[0047] Deep-fixed photoinitiator TMO: 3 parts

[0048] Fumed silica R202: 6 parts

[0049] Fluorescent agent OB: 0.2 parts

[0050] Preparation method:

[0051] Premixing process: Add the above components to the mixing container in sequence according to the required proportions. First, mix the polyurethane acrylic resin DR-U249, SW8801 and LED01 evenly. Then add the acrylic monomers IBOA and DMAA, followed by the surface-drying photoinitiator MBF and the deep-curing photoinitiator TMO. Finally, add the silane coupling agent KH570, fumed silica R202 and fluorescent agent OB and stir to ensure that all components are evenly dispersed to obtain a homogeneous adhesive.

[0052] The mixed adhesive was adjusted to 8000 mPa·s (25°C) at room temperature to ensure that the adhesive had the appropriate fluidity for the wire harness coating process.

[0053] Apply the prepared adhesive to the surface of the wire harness that needs to be sealed, ensuring that the adhesive covers the surface evenly and avoiding air bubbles and uneven application.

[0054] Curing was performed using a 365nm wavelength ultraviolet light source from an LED. The curing conditions were set as follows: light intensity 250mW / cm², irradiation time 3 seconds. Under these conditions, the adhesive achieved both surface and deep curing in a short time, balancing rapid curing with excellent bonding performance.

[0055] Example 2

[0056] UV low-energy fast-curing wire harness sealants include:

[0057] Polyurethane acrylic resin DR-U249: 72 parts

[0058] Trifunctional polyurethane acrylic resin L8401: 22 parts

[0059] Thiol-modified polyurethane acrylic resin LED01: 17 parts

[0060] Acrylic monomer ACMO: 55 parts

[0061] Acrylic monomer DMAA: 25 parts

[0062] Silane coupling agent KH570: 2.5 parts

[0063] Surface-drying photoinitiator MBF / 184 compound: 6 parts

[0064] Deep-fixing photoinitiator TPO-L: 4 parts

[0065] Fumed silica R202: 5 parts

[0066] Fluorescent agent OB: 0.15 parts

[0067] Preparation process:

[0068] Add the above components to the mixing container in the required proportions. First, thoroughly premix the polyurethane acrylic resins DR-U249, L8401, and LED01. Then, add the acrylic monomers ACMO and DMAA, followed by the surface-drying photoinitiator MBF / 184 compound system and the deep-curing photoinitiator TPO-L. Finally, add the silane coupling agent KH570, fumed silica R202, and fluorescent agent OB, and stir thoroughly to obtain a homogeneous adhesive solution.

[0069] The mixed adhesive was adjusted to 8000 mPa·s (25°C) at room temperature to ensure that the adhesive had the appropriate fluidity for the wire harness coating process.

[0070] Apply the prepared adhesive to the surface of the electronic wire harness terminals or connectors that need to be sealed, ensuring that the adhesive covers the surface evenly and avoiding air bubbles and uneven application.

[0071] Curing was performed using a 365nm wavelength ultraviolet light source from an LED. The curing conditions were set as follows: light intensity 280mW / cm², irradiation time 4 seconds. Under these conditions, the adhesive achieved surface and deep curing in a short time, ensuring rapid curing and strong adhesion.

[0072] Example 3

[0073] UV low-energy fast-curing wire harness sealants include:

[0074] Polyurethane acrylic resin DR-U249: 78 parts

[0075] Fast-curing bifunctional polyurethane acrylic resin SW8801: 22 parts

[0076] Thiol-modified polyurethane acrylic resin LED01: 19 parts

[0077] Acrylic monomer TMCHA: 52 parts

[0078] Acrylic monomer DMAA: 28 parts

[0079] Silane coupling agent KH570: 2 parts

[0080] Surface-drying photoinitiator 1173 / 651 compound: 6 parts

[0081] Deep-fixed photoinitiator 819: 4 parts

[0082] Fumed silica R202: 6 parts

[0083] Fluorescent agent OB: 0.25 parts

[0084] Preparation process:

[0085] Add all components to the mixing container in the order specified in the above formulation. First, thoroughly premix the polyurethane acrylic resins DR-U249, SW8801, and LED01. Then add the acrylic monomers TMCHA and DMAA, followed by the surface-drying photoinitiator 1173 / 651 compound system and the deep-curing photoinitiator 819. Finally, add the silane coupling agent KH570, fumed silica R202, and fluorescent agent OB, and stir thoroughly to obtain a homogeneous adhesive solution.

[0086] The mixed adhesive is adjusted to 8000 mPa·s (25°C) at room temperature to ensure that the adhesive has appropriate fluidity and viscosity to facilitate the wire harness coating process.

[0087] Apply the adhesive evenly to the surface of the wire harness to be sealed, ensuring that the adhesive covers the surface evenly without bubbles or uneven application.

[0088] Curing was performed using a 365nm wavelength ultraviolet light source from an LED. The curing conditions were set as follows: light intensity 260mW / cm², irradiation time 4 seconds. Under these conditions, the adhesive achieved rapid surface and deep curing in a short time, ensuring efficient curing and strong adhesion.

[0089] The UV low-energy rapid-curing wire harness sealants prepared in Examples 1-3 were subjected to performance testing, and the testing methods are as follows:

[0090] (1) Tensile strength test

[0091] Testing standards:

[0092] Tensile tests were performed according to ASTM D638 standard.

[0093] Measurements were taken using a universal testing machine.

[0094] 1. Sampling: Cut the cured adhesive sample into standard tensile specimens of specified dimensions (usually rectangular sheet samples 10mm wide and 100mm long).

[0095] 2. Preparation: Clamp both ends of the sample in the fixtures of the testing machine, ensuring that the sample is flat and free of air bubbles.

[0096] 3. Tensile test: Set the tensile speed (10 mm / min) according to ASTM D638 standard until the sample breaks.

[0097] 4. Record the results: Measure the maximum tensile strength, in MPa.

[0098] 5. Calculation: The tensile strength is calculated by the ratio of the maximum load to the cross-sectional area of ​​the specimen.

[0099] (2) Elongation at break test

[0100] Testing standards:

[0101] Tensile tests were performed according to ASTM D638 standard.

[0102] Measurements were taken using a universal testing machine.

[0103] 1. Sampling: Cut the sample according to ASTM D638 standard.

[0104] 2. Preparation: Install the sample in the testing machine fixture.

[0105] 3. Tensile test: Stretch the sample until it breaks and record the maximum elongation.

[0106] 4. Record the results: Record the original length of the specimen and the length after fracture.

[0107] 5. Calculation: Use the formula: Elongation at break (%) = [(Length after break, original length) / Original length] × 100%.

[0108] (3) Shear strength test

[0109] Testing standards:

[0110] Shear strength was tested according to ASTM D1002 standard.

[0111] Measurements were taken using a universal testing machine.

[0112] 1. Sampling: Prepare samples of different substrates (PCPA66, PCPA+10%GF, PCPA66+30%GF), and apply adhesive to the bonding surface of the substrate.

[0113] 2. Curing: Curing the adhesive sample according to the curing conditions specified in the claims.

[0114] 3. Preparation: Install the cured sample in the fixture of the testing machine, ensuring that the adhesive surface of the sample is in contact with the fixture of the testing machine.

[0115] 4. Shear test: Set the tensile speed (1 mm / min) according to ASTM D1002 standard until the sample fails in shear.

[0116] 5. Record the results: Record the maximum shear load and calculate the shear strength.

[0117] 6. Calculation: Shear strength = maximum shear load / bond area, unit is MPa.

[0118] (4) Shear strength (PCPA66) test

[0119] The test procedure used PCPA66 substrate for testing, and the shear strength (unit: MPa) was recorded.

[0120] (5) Shear strength (PCPA+10%GF) test

[0121] Test procedure: Use PCPA+10%GF substrate for testing and record the shear strength (unit: MPa).

[0122] (6) Shear strength (PCPA66+30%GF) test

[0123] Test procedure: The test was conducted using PCPA66+30%GF substrate, and the shear strength (unit: MPa) was recorded.

[0124] The test results are shown in Table 1 below.

[0125] Table 1

[0126]

[0127] Based on the performance test data of Examples 1-3, it can be seen that the UV low-energy rapid curing wire harness sealant of the present invention exhibits good comprehensive performance in key properties such as tensile strength, elongation at break and shear strength, indicating that it has excellent performance and wide applicability in practical applications.

[0128] 1. Balance between tensile strength and elongation at break:

[0129] The tensile strength of Example 1 reached 14 MPa, Example 2 12 MPa, and Example 3 13 MPa; the elongation at break was 80%, 75%, and 78%, respectively. This indicates that after compounding with fast-curing bifunctional or trifunctional polyurethane acrylic resin, the curing rate of the system was improved. Since DR-U249 itself has good flexibility, the adhesive layer did not become brittle and maintained a high elongation at break, thus achieving a balance between tensile strength and flexibility.

[0130] 2. Excellent adhesion to difficult-to-bond substrates such as PA:

[0131] In shear strength tests, especially on substrates such as PC-PA66 and PC-PA66+30%GF, the adhesive of this invention exhibits excellent bonding performance. Taking Example 1 as an example, its shear strength reached 3.6 MPa and 4.2 MPa, respectively; even on PC-PA+10%GF substrates, it can maintain a good shear strength level, indicating that this invention has good adhesion and compatibility with difficult-to-bond substrates such as PA.

[0132] 3. Low-energy rapid curing and high-efficiency production:

[0133] All embodiments achieved rapid curing under low-energy (200~300mW / cm²) UV light irradiation, with a curing time of 3~5 seconds. This feature helps improve production efficiency, shorten production cycles, and reduce energy consumption while ensuring curing effect, meeting the requirements of modern manufacturing for high efficiency and energy saving.

[0134] The UV low-energy fast-curing wire harness sealant of this invention successfully balances adhesion performance, rapid curing capability, and system flexibility through precise formulation design and optimized curing conditions. Performance testing results verify the application value of this adhesive in wire harness sealing and protection applications requiring high strength and high reliability.

[0135] The technical solution of this invention provides stable performance while achieving high-efficiency production, significantly improving product reliability and service life, while reducing production costs and energy consumption, meeting the requirements of modern industry for high-efficiency, environmentally friendly and high-performance materials.

[0136] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A UV low-energy fast-curing wire harness sealant, characterized in that, The wire harness sealant comprises the following components: The main resin is a polyurethane acrylic resin, which has excellent adhesion to nylon terminals; At least one surface-drying photoinitiator is used to inhibit oxygen inhibition and improve surface drying effect; At least one deep-curing photoinitiator is used to achieve deep curing of the adhesive layer; Acrylic monomers are used to improve adhesion, adjust viscosity, and improve flowability. At least one additive is used to improve the adhesion, flowability and curing properties of the adhesive.

2. The UV low-energy rapid-curing wire harness sealant according to claim 1, characterized in that, The main resin is polyurethane acrylic resin, specifically DR-U249, with a mass ratio of 70-80 parts.

3. The UV low-energy rapid-curing wire harness sealant according to claim 1, characterized in that, The proportion of the polyurethane acrylic resin in the main resin is 70-80 parts, and at least one fast-curing bifunctional or trifunctional polyurethane acrylic resin, specifically SW8801 or L8401, is added, accounting for 20-30 parts by mass.

4. The UV low-energy rapid-curing wire harness sealant according to claim 1, characterized in that, The surface-curing photoinitiator is a photoinitiator that can inhibit oxygen inhibition polymerization, specifically MBF, with a mass ratio of 5-7 parts, used to improve the surface curing effect.

5. The UV low-energy rapid-curing wire harness sealant according to claim 1, characterized in that, The deep-curing photoinitiator is TMO, with a mass ratio of 3-5 parts, used to achieve deep curing of the adhesive layer.

6. The UV low-energy rapid-curing wire harness sealant according to claim 1, characterized in that, The acrylic monomers are IBOA and DMAA, with IBOA accounting for 50-60 parts by mass and DMAA accounting for 20-30 parts by mass, used to improve adhesion and adjust the viscosity of the system.

7. The UV low-energy fast-curing wire harness sealant according to claim 1, characterized in that, The additive is a silane coupling agent, specifically KH-570, with a mass ratio of 1 to 3 parts, used to enhance the adhesion between the adhesive and the nylon substrate.

8. The UV low-energy rapid-curing wire harness sealant according to claim 1, characterized in that, The fumed silica in the wire harness sealant is R202, with a mass ratio of 5-8 parts, used to provide thixotropy and reduce system flowability.

9. The UV low-energy rapid-curing wire harness sealant according to claim 1, characterized in that, The fluorescent agent in the wire harness sealant is OB, with a mass ratio of 0.1 to 0.3 parts, used to provide color recognition during the dispensing process.

10. The UV low-energy rapid-curing wire harness sealant according to claim 1, characterized in that, The curing conditions for the wire harness sealant are an LED 365nm light source with a curing light intensity of 200~300mW / cm². 2 The irradiation time is 3 to 5 seconds.

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