Thermal activation type horn drum paper bonding adhesive and preparation method thereof

Abstract

The invention relates to a thermal activation type horn drum paper bonding adhesive, which comprises the following components in percentage: main material resin, auxiliary material resin, a diluent, a filler and an auxiliary agent, wherein the main material resin is styrene-butadiene polymer resin; the auxiliary resin is one or more of rosin, modified rosin, hydrocarbon resin, terpene resin and coumarone resin; the diluent is one or more of toluene, xylene, ethyl acetate, butyl acetate, isoamyl acetate, cyclohexane and cyclohexanone; the filler is a mixture of nano aluminum oxide and nano magnesium oxide; the auxiliary agent comprises an antioxidant and one or two of a defoaming agent and a dispersing agent. The laminating adhesive disclosed by the invention has the characteristics of excellent thixotropic property, good processability, wide bonding range, high bonding strength, excellent tensile property, good elasticity and good toughness, is shorter in hot-pressing processing time, and can meet the requirement of assembly line work with higher strength; the practicability is high, and the popularization significance is high.

Description

Technical Field

[0001] The invention relates to a bonding adhesive, in particular to a heat-activated speaker drum paper bonding adhesive and a preparation method thereof. Background Art

[0002] The speaker drum paper, also known as the vibration plate or cone, is one of the main parts of the speaker. It is made of the carcass and the sapwood. The bonding effect of the carcass and the sapwood has a decisive influence on the performance and sound quality of the speaker. At present, the carcass and the sapwood are usually bonded together with glue. The specific operation method is to evenly glue the sapwood bonding part, dry it at room temperature for 24 hours or bake it in a drying tunnel and then cool it to room temperature. Place the carcass and the sapwood on the fixed fixture of the hot press, set the bonding temperature, air pressure and bonding time, and then perform hot pressing to obtain the finished product.

[0003] However, the traditional laminating glue has the following problems: for various products and speakers with different functions, the materials of the body and sapwood are also different, such as: the body material includes paper, PP plastic, woven glass, fiber, woven carbon fiber, bulletproof cloth, polyester film, phenolic resin film and various metal plates such as aluminum and stainless steel; and the sapwood material includes cloth edge, EVA foam material, PU foam material, TPU film and various rubbers such as NBR, SBR, butyl rubber, EPDM rubber and Santoprene; the material combination of different body and sapwood is ever-changing. However, most of the existing laminating glues have high bonding performance only for one or a few materials, and the heat-activated adhesives currently on the market have poor hot pressing performance and require a long hot pressing time, which cannot meet the needs of speaker manufacturers for rapid production. Summary of the invention

[0004] To this end, the object of the present invention is to provide a heat-activated speaker drum paper laminating adhesive and a preparation method thereof to solve the problems in the background technology.

[0005] To achieve the above purpose, the present invention mainly adopts the following technical solutions:

[0006] A heat-activated speaker drum paper bonding adhesive, comprising the following percentage components:

[0007]

[0008] The main resin is a styrene-butadiene polymer resin with a rubber segment (butadiene segment) content of at least 68% or more; the auxiliary resin is a mixture of rosin, hydrocarbon resin, and terpene resin; the diluent is one or more of toluene, xylene, ethyl acetate, butyl acetate, isopentyl acetate, cyclohexane, and cyclohexanone; the filler is a mixture of nano-alumina and nano-magnesium oxide; and the auxiliary agent includes an antioxidant.

[0009] Furthermore, the amount of rosin added cannot exceed 5% of the total weight of the auxiliary resin.

[0010] Furthermore, the addition ratio of the hydrocarbon resin to the terpene resin is 7:2.

[0011] Furthermore, the rosin is modified rosin.

[0012] Furthermore, the added amount of the filler is 0.6% to 2.2%.

[0013] Furthermore, the auxiliary agent also includes one or more of a defoaming agent and a dispersant.

[0014] Furthermore, the filler is a mixture of α-type nano-alumina and spherical nano-magnesia.

[0015] A method for preparing a heat-activated speaker drum paper laminating adhesive comprises the following steps:

[0016] Step 1: Prepare the following ingredients in percentage:

[0017]

[0018] The main resin is a styrene-butadiene polymer resin with a rubber segment (butadiene segment) content of at least 68% or more; the auxiliary resin is a mixture of rosin, hydrocarbon resin, and terpene resin; the diluent is one or more of toluene, xylene, ethyl acetate, butyl acetate, isopentyl acetate, cyclohexane, and cyclohexanone; the filler is a mixture of nano-alumina and nano-magnesium oxide; and the auxiliary agent includes an antioxidant.

[0019] Step 2, preparing a resin solution of component A and a filler slurry of component B;

[0020] 1) Prepare the resin solution of component A; dissolve 20-40% of the auxiliary resin in about two-thirds of the total amount of diluent, and control the temperature of the reactor at 40°C to 50°C; stir for 20min to 40min until the auxiliary resin is completely dissolved, and cool to room temperature for use;

[0021] 2) Prepare filler slurry of component B; dissolve 0.5-8% filler in about one-third of the total amount of diluent, and stir for 20-30 minutes until the filler is evenly dispersed;

[0022] Step 3: Control the temperature at 20-30°C, slowly add the filler slurry of component B into the resin solution of component A, mix thoroughly and stir evenly;

[0023] Step 4: After the mixture of components AB is evenly mixed, add 20-40% of the main material resin into the chemical reactor, evacuate the reactor, control the temperature at 60-80°C, continue stirring for 80-90 minutes, then add the formulated amount of defoamer, dispersant and antioxidant in sequence, continue stirring until it becomes a homogeneous viscous glue liquid, stop stirring to obtain the finished product.

[0024] Furthermore, the amount of rosin added cannot exceed 5% of the total weight of the auxiliary resin.

[0025] Furthermore, the addition ratio of the hydrocarbon resin to the terpene resin is 7:2.

[0026] Furthermore, the rosin is modified rosin.

[0027] Furthermore, the added amount of the filler is 0.6% to 2.2%.

[0028] Furthermore, the auxiliary agent also includes one or more of a defoaming agent and a dispersant.

[0029] Furthermore, the filler is a mixture of α-type nano-alumina and spherical nano-magnesia.

[0030] In summary, the laminating adhesive of the present invention has the characteristics of superior thixotropic performance, good processing performance, wide bonding range, high bonding strength, excellent tensile performance, good elasticity and good toughness. It provides an excellent solution for the problems of weak bonding and unsmooth gluing in speaker production and processing factories, and can fill the gap in the speaker drum paper laminating adhesive market, meet the requirements of bonding between the speaker drum paper shavings and the carcass, and meet the reliability test and sound quality test requirements of the speaker finished product, such as drop test and vibration test. In addition, it has more prominent thermal activation than traditional laminating adhesives. After the adhesive is dried and cooled, as the temperature rises to a certain range, the resin component in the adhesive dry film will be converted into a molten state, lose the cross-linking effect, and restore physical cross-linking after cooling, so that the drum paper shavings and the carcass are firmly bonded after the temperature change of heating-cooling. And the addition of special nano fillers (can shorten the hot pressing processing time of the adhesive, which can meet the needs of higher-intensity assembly line operations. The present invention has strong practicality and strong promotion significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is one of the relationship diagrams between the amount of filler added and the tensile strength and peel strength of the heat-activated speaker drum paper laminating adhesive of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0033] The present invention provides a heat-activated speaker drum paper bonding adhesive, which is used to bond the body and edge material of speaker drum paper of earphones, mobile phones, tablets, and laptops. It can be understood that it can also be applied to other fields according to needs, and its specific application scope is not limited here.

[0034] The heat-activated speaker drum paper bonding adhesive includes the following percentage components:

[0035]

[0036] Wherein, the main material resin is a styrene-butadiene polymer resin, which is a styrene-based thermoplastic resin polymerized with styrene and butadiene as monomers, and its molecular chain is composed of a hard plastic segment (styrene segment) and a flexible rubber segment (butadiene segment), so that it has the characteristics of both plastic and rubber. Preferably, the main material resin is a polymer resin with a higher content of rubber segments (butadiene segments). More specifically, the main material resin is a styrene-butadiene polymer resin with a rubber segment (butadiene segment) content of at least 68% or more.

[0037] When the content of rubber segment polymer is high, the plastic segment is distributed in spherical shape between continuous rubber segments. Due to the presence of plastic phase in the resin, the movement of its molecular chain segments is restricted, showing a physically cross-linked state, but this cross-linking is reversible. When the resin is heated to a certain temperature by a hot press, the plastic phase melts and loses its cross-linking effect. After the heating is stopped and the melt is cooled, the plastic phase resumes its effect and the resin molecules return to a physically cross-linked state; thus, the glue prepared by it has good thermal activity.

[0038] The auxiliary resin is one or more of rosin, modified rosin, hydrocarbon resin, terpene resin, and coumarone resin. In the present embodiment, the auxiliary resin is a mixture of rosin with low price and terpene resin and hydrocarbon resin with high softening point. As one of the most commonly used tackifying resins for adhesives, rosin has the characteristics of low price, can increase the toughness of adhesives, initial viscosity and improve bonding strength, but rosin itself has a double bond structure and crystallization characteristics, is easily oxidized during storage, and is easily crystallized in organic solvents, which can reduce the storage stability of adhesives. Therefore, the addition of rosin should not exceed 5% of the gross weight. The addition of hydrocarbon resin and terpene resin can improve thermal stability, can improve the tensile properties and cohesive strength of adhesives to a certain extent, the difference between the two is that hydrocarbon resin can give more bonding strength to adhesives but can reduce the cohesive strength of adhesives, terpene resin can improve the cohesive strength of adhesives, improve tensile properties and provide certain antioxidant properties. Preferably, when the hydrocarbon resin and the terpene resin are added in an amount of about 7:2, a more balanced bonding property and tensile property can be obtained.

[0039] In addition, a mixture of modified rosin, terpene resin and hydrocarbon resin can be used as auxiliary resin, which is better than the mixture of rosin, terpene resin and hydrocarbon resin in performance; but in terms of price cost, it is more expensive than using rosin.

[0040] The diluent is one or more of toluene, xylene, ethyl acetate, butyl acetate, isoamyl acetate, cyclohexane and cyclohexanone.

[0041] The filler is a mixture of one or more of nano silicon dioxide, aluminum silicate, nano aluminum hydroxide, nano aluminum oxide, and nano magnesium oxide. Preferably, the filler is a mixture of nano aluminum oxide and nano magnesium oxide. In the present embodiment, the nano aluminum oxide and nano magnesium oxide are α-type nano aluminum oxide and spherical nano magnesium oxide. α-type nano aluminum oxide has low reactivity, low specific surface area, flame retardancy, high temperature resistance and excellent thermal conductivity, while spherical nano magnesium oxide has high specific surface area, high fire resistance and more outstanding thermal conductivity. The combination of the two can not only effectively improve the surface wetting properties, thixotropic properties and tensile properties of the adhesive, but also improve the thermal activation properties of the adhesive of the present invention, so that the hot pressing time required for the processing of the speaker drum paper is shorter, the processing speed is accelerated, and the production efficiency is improved. Furthermore, when the amount of nano filler added in the adhesive is 0.6% to 2.2%, it can show excellent bonding and tensile properties.

[0042] The auxiliary agent includes an antioxidant, and may also include one or both of a defoamer and a dispersant. Preferably, the defoamer is selected from one or more of the models BYK-073 and BYK-077 of German BYK Company or the domestic brands CI-1678 and CI-3175. The dispersant is one or more of the models SC-0708A and AAB-0851 of Japan's NOK Corporation or the models BYK-109 and BYK-111 of German BYK Company. The antioxidant is selected from one or a mixture of domestic brands antioxidant 1010, antioxidant RD and antioxidant AW. Because the main material resin is a styrene-butadiene polymer resin, the molecular chain of this resin contains a double bond structure, which is easily oxidized or cross-linked by moisture, oxygen, ultraviolet rays, etc. during storage and use, affecting normal use. Therefore, the addition of an antioxidant is indispensable.

[0043] The beneficial effects of the laminating adhesive of the present invention are:

[0044] 1) It has a wide range of bonding and has good bonding effects on a variety of materials, including different body materials, such as paper, PP plastic, woven glass, fiber, woven carbon fiber, bulletproof cloth, polyester film, phenolic resin film and various metal plates such as aluminum and stainless steel; and different edge materials, such as cloth edges, EVA foam materials, PU foam materials, TPU films and various rubbers such as NBR, SBR, butyl rubber, EPDM rubber and TPE. The reason is that: from a microscopic point of view, the bonding surfaces of the sapwood and the carcass are both uneven surfaces, while the bonding adhesive of the present invention has a short hot pressing time and strong fluidity after melting. The melted adhesive molecules can fully diffuse and penetrate into the tiny depressions on the surface of the sapwood and the carcass, achieving an excellent wetting effect. After the temperature is cooled and the adhesive is restored to a cross-linked state, it can provide a stronger bonding force, and the nano-filler with a smaller particle size increases the toughness of the adhesive; some objects that are difficult to bond themselves can also be firmly bonded due to this special physical, chemical and mechanical bonding force generated by the infiltration of the depressions.

[0045] 2) Excellent processing performance; it can adapt to the gluing methods such as needle dispensing, spraying, roller coating, pad printing, etc. The bonding glue in the present invention can effectively improve the thixotropic properties of the adhesive because the nano filler is added and the filler is fully dispersed in the resin molecular structure, so that there will be no drawing phenomenon during gluing, and the gluing is smooth.

[0046] 3) It has higher thermal conductivity; the addition of the nano filler composed of α-type nano alumina and spherical nano magnesium oxide makes the hot pressing time required for processing shorter than that of traditional bonding adhesives. The hot press machine is set at a temperature of 120℃~130℃ and only needs hot pressing for 2s~3s to fully bond, which can meet the needs of faster assembly line production operations.

[0047] 4) Outstanding bonding performance; after drying and cooling, hot pressing and bonding, the peel strength of ABS and 9# canvas can reach more than 20N / 15mm, and the maximum shear force of the common difficult-to-bond NBR sedge material and paper carcass can reach more than 50N (bonding area 5mm*20mm).

[0048] In addition, the following Tables 1 and 2 are partial experimental data tables for reference.

[0049]

[0050] Table 1 is the experimental data table of five different ratio embodiments

[0051]

[0052] Table 2 shows the performance test conditions and results of the five different ratio embodiments in Table 1.

[0053] In addition, the present invention also discloses a method for preparing a heat-activated speaker drum paper laminating adhesive, so as to prepare the heat-activated speaker drum paper laminating adhesive. The method specifically comprises the following steps:

[0054] Step 1, material preparation, prepare materials with the following percentage composition, main material resin 20-40%, auxiliary material resin 20-40%, diluent 30-50%, filler 0.3-5%, auxiliary agent 0-2%; the specific composition of the above materials is consistent with the components and specific ingredients of the aforementioned heat-activated speaker drum paper bonding adhesive; therefore, they will not be repeated here.

[0055] Step 2, preparing a resin solution of component A and a filler slurry of component B;

[0056] 1) Prepare the resin solution of component A: dissolve 20-40% of the auxiliary resin in about two-thirds of the total amount of diluent, and control the temperature of the reactor at 40℃~50℃. In this temperature range, the dissolution speed of the resin is significantly accelerated and the dissolution is more thorough. Stir for 20min~40min until the auxiliary resin is completely dissolved, and cool to room temperature for use.

[0057] 2) Prepare filler slurry of component B: dissolve 0.5-8% of filler in about one-third of the total amount of diluent, and stir for 20-30 minutes until the filler is evenly dispersed. This is filler slurry of component B;

[0058] Step 3: Control the temperature at 20-30°C, slowly add the filler slurry of component B to the resin solution of component A, mix thoroughly and stir evenly. The auxiliary resin is easier to dissolve completely under heating conditions, but the auxiliary resin is easy to agglomerate after heating, and the surface tension of the resin solution is large. It is difficult for fillers with nano-sized particles to directly enter the resin system. Therefore, the filler needs to be made into filler slurry before mixing with the resin solution.

[0059] Step 4: After the mixture of components AB is evenly mixed, add 20-40% of the main material resin into the chemical reactor, evacuate the reactor, control the temperature at 60-80°C, continue stirring for 80-90 minutes, then add the formulated amount of defoamer, dispersant and antioxidant in sequence, continue stirring until it becomes a homogeneous viscous glue liquid, stop stirring to obtain the finished product.

[0060] In summary, the laminating adhesive of the present invention has the characteristics of superior thixotropic performance, good processing performance, wide bonding range, high bonding strength, excellent tensile performance, good elasticity and good toughness. It provides an excellent solution for the problems of weak bonding and unsmooth gluing in speaker production and processing factories, and can fill the gap in the speaker drum paper laminating adhesive market, meet the requirements of bonding between the speaker drum paper shavings and the carcass, and meet the reliability test and sound quality test requirements of the speaker finished product, such as drop test and vibration test. In addition, it has more prominent thermal activation than traditional laminating adhesives. After the adhesive is dried and cooled, as the temperature rises to a certain range, the resin component in the adhesive dry film will be converted into a molten state, lose the cross-linking effect, and restore physical cross-linking after cooling, so that the drum paper shavings and the carcass are firmly bonded after the temperature change of heating-cooling. And the addition of special nano fillers shortens the hot pressing processing time of the adhesive, which can meet the needs of higher-intensity assembly line operations. The present invention is highly practical and has a strong promotional significance.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A heat-activated speaker drum paper bonding adhesive, characterized in that: The percentage components include: The main resin is a styrene-butadiene polymer resin with a rubber segment (butadiene segment) content of at least 68% or more; the auxiliary resin is a mixture of rosin, hydrocarbon resin, and terpene resin; the diluent is one or more of toluene, xylene, ethyl acetate, butyl acetate, isopentyl acetate, cyclohexane, and cyclohexanone; the filler is a mixture of nano-alumina and nano-magnesium oxide; and the auxiliary agent includes an antioxidant.

2. The heat-activated speaker drum paper laminating adhesive according to claim 1, characterized in that: The amount of rosin added should not exceed 5% of the total weight of the auxiliary resin.

3. The heat-activated speaker drum paper laminating adhesive as claimed in claim 2, characterized in that: The addition ratio of the hydrocarbon resin to the terpene resin is 7:

2.

4. The heat-activated speaker drum paper laminating adhesive according to claim 1, characterized in that: The rosin is modified rosin.

5. The heat-activated speaker drum paper laminating adhesive according to claim 1, characterized in that: The added amount of the filler is 0.6% to 2.2%.

6. The heat-activated speaker drum paper laminating adhesive according to claim 1, characterized in that: The auxiliary agent also includes one or more of a defoamer and a dispersant.

7. The heat-activated speaker drum paper laminating adhesive according to claim 1, characterized in that: The filler is a mixture of α-type nano-alumina and spherical nano-magnesia.

8. A method for preparing a heat-activated speaker drum paper laminating adhesive, characterized in that: The method comprises the following steps: Step 1: material preparation, preparing the material composition of the heat-activated speaker drum paper bonding adhesive as claimed in any one of claims 1 to 7; Step 2, preparing a resin solution of component A and a filler slurry of component B; 1) Prepare the resin solution of component A; dissolve 20-40% of the auxiliary resin in about two-thirds of the total amount of diluent, and control the temperature of the reactor at 40°C to 50°C; stir for 20min to 40min until the auxiliary resin is completely dissolved, and cool to room temperature for use; 2) Prepare filler slurry of component B; dissolve 0.5-8% filler in about one-third of the total amount of diluent, and stir for 20-30 minutes until the filler is evenly dispersed; Step 3: Control the temperature at 20-30°C, slowly add the filler slurry of component B into the resin solution of component A, mix thoroughly and stir evenly; Step 4: After the mixture of components AB is evenly mixed, add 20-40% of the main material resin into the chemical reactor, evacuate the reactor, control the temperature at 60-80°C, continue stirring for 80-90 minutes, then add the formulated amount of defoamer, dispersant and antioxidant in sequence, continue stirring until it becomes a homogeneous viscous glue liquid, stop stirring to obtain the finished product.

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