Development of speaker adhesive

   In the "Tenth Five Year" period, China electro acoustic devices industry rapid development, technical level and product quality rapidly improved, forming a electroacoustic device producer and exporter from parts processing to finished product design and production of a complete industrial chain, has become the first in the world, electro acoustic devices in the world's production center. In order to meet the market of electro acoustic devices are more and more high requirements, electronic industry in the continuous innovation, the application of new technology and new materials is increasing. At the same time, the application of adhesive in the electroacoustic devices in presents new challenges, this paper outlines the speaker adhesive faces new challenges, new progress and development trend.
    1、New challenges for speaker adhesives
    1．High power of speaker
    Super bass speakers and car speakers tend to large power, large caliber, such as JBL company W15GTI super bass loudspeaker rated power of 2000W, instantaneous power 5000W and magnat company Omega 530 speaker caliber for 20 ", the larger speaker caliber in more than 30". The challenge to the adhesive: Psychotenology, Inc., a real-time system for measuring the temperature of the voice coil at the 2006 ALMA Winter Conference, shows that the speaker can be up to 350 degrees Celsius in a certain working condition. This is enough to show that more and more power, the size of the speaker on the adhesive, especially the central adhesive is also increasingly resistant to temperature requirements.
    2. Speaker miniaturization
    With the development of mobile phones, laptops, MP3, MP4, PDA and so on, these products are required to be miniaturized and high fidelity. For example, the piezoelectric speaker size Japan Murata new only 31 x 16 x 1mm3.
    The challenge of adhesive: in addition to consider adhesive itself on the sound quality effect, but also consider the effects of sizing technics of consistency of quality, adhesive to facilitate the consistency of the gelatinize control and guarantee mixed or curing effect.
    3. A variety of speakers of new materials
    With the rapid development of material science and technology, a large number of new material and speaker accessories have been developed in recent years, which not only improves the performance of the speakers but also increases the aesthetic effect. Almost all of the accessories are new materials for the application:
    T iron, plywood: chrome, electrophoretic paint
    Magnet: NdFeB and alnico
   Frame: PP, gold, copper and aluminum frame finish
    Membrane: PP, HOROFINE, pure silk, pure carbon, polyester, metal titanium, aluminum, diamond film, Kevlar;amp; reg;
   Wave: NOMEX, PEEK
    Voice coil: Kapton, metal
    The challenge to the adhesive: adhesion to a variety of new materials.
    4. Environmental protection requirements of the international market
   In 2003 the European Union issued the RoHS-2002/95/EC directive "electronic and electrical equipment to restrict the Hazardous Substances Regulations", in July 1, 2006 the mandatory implementation, the specific requirements for:
    Pb 1000ppm
    Cd 100ppm
    Hg 1000ppm
    Cr+6 1000ppm
    PBB 1000ppm
    PBDE 1000ppm
    In 2003 the European Union issued the WEEE-2002/96/EC directive, "the waste electronic equipment directive", was forced to implement in August 13, 2005. Instruction for the recycling of waste electronic equipment. Speakers are consumer equipment, the recovery rate to reach 70%, and then the utilization rate to reach 50%.
    February 28, 2006 China's seven ministries jointly issued the "electronic information products pollution control management approach", will be implemented in March 1, 2007.
    The challenge to the adhesive: the adhesive contains toxic substances in line with the limited requirements, suitable for the use of environmentally friendly new material of the speaker's accessories, adhesive not only to the speaker parts bonding solid, but also easy to recycle when part of the separation.
    5.TECHNOLOGY GMBH NOKIA (DE) has been applied in several countries for the design of a number of countries, the structure of the high temperature sound coil is applied for a number of countries. China Gansu rare earth research company development and design of the non vibrating film speakers, the Chinese product name is "free to listen", without the vibration and elastic wave, it is not the center of plastic, edge and elastic wave. In January 16, 2006 the Toyota Corporation announced that the new "Estima" of all the models are used to form a speaker through the vibration roof liner plate speaker technology. The technology uses the Transducers Limited NXT of the UK New flat panel speaker technology.
    The challenge to the adhesive: because the novel design and the traditional loudspeaker structure is completely different, not only is the challenge to the technical level of the speaker, but also is a challenge to the development of the speaker adhesive.
    2、The development of domestic and foreign speaker adhesive
    1．Domestic and foreign speakers adhesive major manufacturers of speakers adhesive manufacturers mainly in the United States Hernon, Dymax, Germany's Loctite Henkel, Japan's Cemedine, Nogawa, Denka. The speaker adhesive manufacturers are mainly Shanghai, Shanghai Kangda three flowers, Huizhou Hengda, three (Taiwan) etc..
    2.Quality level of domestic and foreign speaker adhesive
    At present, there are some gaps in the quality of the speakers at home and abroad, the main performance in the domestic some of the adhesive properties than the poor quality of foreign products and product quality is not very good. Therefore, the current foreign products are mainly used in high-end speakers, domestic products are mainly used in middle and low speakers.    3. Application status of domestic and international speaker adhesive
    The speaker with glue to two-component acrylate adhesive and one component solvent adhesive mainly, the existence of performance, odor and toxicity issues. Europe and the United States speaker with glue to anaerobic adhesive and high performance cyanoacrylate glue based, UV glue, epoxy glue application is gradually increasing. Anaerobic adhesive component, low odor, fast curing advantages, high performance alpha cyanoacrylate glue is solvent free, one component, fast curing, good applicability of materials advantages.    In addition, abroad in the development and application of better performance, plastic process more convenient and more environment-friendly new kind of rubber, such as UV curing alpha - cyanoacrylate glue, VL glue (visible light curing adhesive), multiple curing UV glue and pre activation of one component epoxy adhesive.    4. New progress of domestic and foreign speaker adhesive
    （1）Anaerobic adhesive
    Anaerobic adhesive used for less than 0.125 of the magnetic circuit bonding, with the use of the accelerator can be located within a few seconds, 24 hours completely cured. For example, the Hasa company's -50/121 716 anaerobic adhesive and Primer EF 50 promoter, the application temperature range Hernon.
    Dymax846 series of anaerobic adhesive, viscosity 5000-30000cPs, with the use of 540-ER accelerator, the application temperature range of -55/150;
    （2）Acrylic adhesive
    Acrylic adhesive used in the gap greater than 0.125 of the magnetic circuit adhesive bonding, and the use of the accelerator can be used in a few seconds, 24 hours completely cured. For example Hernon ReAct 727 acrylate adhesive and Primer EF 56 promoter, the application of temperature range of -50/121.
    Loctite Company 324/7075、326/7694、332/7387、392/7387The combination of acrylic ester and accelerator, high viscosity 17000 -200000cps, 332 heat resistance of -50/200.
    American Cyberbond company Cybercryl 1326 Acrylic adhesive /Cybercryl 1094 促进剂,Room temperature for a few minutes,30min/90℃Fully cured, the application temperature range of -55/160, product zero degree of storage.
    （3）High performance cyanoacrylate glue
   Alpha cyanoacrylate glue after modification, can satisfy the different viscosity, heat resistance and flexibility requirements, used in conjunction with the accelerator, can fast and deep cure and prevent surface whitening, in addition to the magnetic circuit part have alpha cyanoacrylate glue. For example, Quantum Hernon 147 and Primer EF 58 promoter as the center glue, using CA Primer EF 42 promoter can be used for PP, PE material, the application of temperature range of -55/107, the positioning / complete curing time is 40-50s/24h. Quantum 134 and EF primer 58 accelerator for sound basin / pot racks, elastic wave / pot racks, dust cap / sound basin, layering / sound basin etc. parts of the bonding, the location / time to fully cure for 40-50s/24h, applicable temperature range -55/82 DEG C;
  & nbsp; & nbsp; loctite Corporation high elastic alpha cyanoacrylate glue has good elasticity, 770, 793, 7951 and accelerator can be used for bonding of PP materials center and other parts. Loctite Corporation Product4303 UV - curing alpha cyanoacrylate glue, location / time to fully cure for 5s/24h, 15s curing depth up to 7mm.
    Lord, CA5019 alpha cyanoacrylate glue for plastic and metal positioning time of 15s and 25s, applicable temperature range -53/121 DEG C, for porous materials and PP, PE, PTFE without surface treatment.
    Adhesive systems, Inc. RP2400 resistant high temperature alpha cyanoacrylate glue, applicable temperature range -65/180 DEG C, using the promoter Quick-TAC2, can be accelerated curing and preventing whitening.
    （4）UV
    Due to the UV component, fast curing, high temperature high, environmental protection and other advantages, in the loudspeaker assembly applications gradually increased, for example DYMAX Corp. with different heat tolerance level of UV center, glue, light weld 20138 location / time to fully cure for 0-60s/24h, applicable temperature range -30/125 DEG C, ultra light WELD3094 series / full curing time for 2-20s/24h, applicable temperature range -55/180 DEG C, ultra light weld 9-20453 positioning / full curing time for 2-20s/24h, applicable temperature range -55/200 degrees. DYMAX Corp. has also developed a new Multi-Cure 605 series multiple curing UV, UV curing 35S positioning and accelerators for activation of a few minutes positioning, site of 110 DEG C, 120 DEG C / 30min, 150 DEG C for 15 min heating fully cured. The combination of UV and other curing methods can be used for the adhesion of magnetic circuit and other non transparent materials.
    Loctite, 3106, 3107, 3108, 3175 and eight used instead of UV glue for voice coil enamelled wire end fixed.
    Loctite corporation also launched a VL glue (visible light curing adhesive) 3552, 3553, while maintaining the advantages of UV, reduce the curing equipment investment, to avoid UV damage to the human body.
    （5）Epoxy adhesive
    Epoxy resin has good heat resistance, mainly used as the center of rubber. The two-component epoxy adhesive for mixed and strict requirements, the use is not convenient, at present to the development of one component epoxy adhesive. Plastics Inc., E30025-1 LEEBOND epoxy resin, three kinds of curing agent, the ratio of 10:1, curing conditions were 20s, 90s, /66 Leepoxy, 200.
    Hernon Conebonder 395 one component epoxy center, glue, curing conditions to 150 DEG C / min and 120 DEG C / 2.5 min and 100 DEG C / 7min, heat-resistant 204 DEG C. Loctite Corporation in 2006 the newly launched the pre activation of one component epoxy adhesive, by UV irradiation the pre activation, in a certain amount of time in bonding and assembling can be quickly positioning, by controlling the time of UV irradiation to adjust the adjustable operation, UV irradiation time range for 5-12s, operation time is 40-250s. 60 for a few minutes or room temperature 6h can be completely cured. Pre activation of one component epoxy adhesive overcome uv gel can not be used for the shortcomings of opaque material, not only can for the central part, can also be used for other parts of the magnetic circuit. (6) other rubber species
   Hernon Hernon voice coil bonder 360 one component phenolic nitrile rubber for Kapton skeleton / coil, Kapton voice ring /Kapton vibration film adhesive, curing conditions for 20 minutes each 82.3 C + 204 DEG C /45min+65 DEG C / 12 h, heat can be up to 315 C. Lord company Lord& reg; 7542 two-component polyurethane adhesive, volume ratio of 1:1, through the static mixer application glue, the operation time of 4-5 min/24 DEG C, hour at room temperature or 6-8 minutes / 60 DEG C or 1.5 min / 93 DEG C at the beginning of the solid, extend double time can be cured completely, for bonding parts of the edge of the edge of the foam, rubber, sound basin, elastic wave, dust cap, layering.
    (7)Kang Daxin product
   Magnetic circuit glue: WD1089 and WD1190 acrylate magnetic flux glue in the original magnetic flux adhesive curing speed, high bonding strength, based on the advantages of significantly reduce the smell and acid.
   WD1053 high temperature resistant acrylic adhesive: basic consistent with the temperature resistance of a certain brand center adhesive used in China.
   WD PP basin neoprene center, glue: and in the domestic use is common of many foreign brands center, glue compared to the peel strength of PP materials have significantly improved.
   Heat-resistant imide center, glue modified bismaleimide: 120 DEG C dried 45min after bonding and 200 DEG C /2h+230 DEG C after curing, with good heat aging properties and applicable temperature range -70/270 DEG C, mainly used for high pitch vibrating diaphragm and a voice coil bonding. Also good bonding strength and heat resistance of different materials. Magnetic primer (chrome plating special): on the chrome plated T iron and splint has very good adhesion, anti drop performance very good, destructive tests were magnets for destruction.
    3、The development trend of the eleven - five "speaker adhesive
    1.Development of adhesive used for bonding of new speakers.
   To open the way, the introduction of more types of adhesives in the application of the speaker assembly to meet the increasing demand for new speakers of new materials.
    2.Improve the temperature resistance of the adhesive
    To modified acrylate, room temperature curing epoxy resin, curing at moderate temperature change of Bismaleimide to imide reaction type rubber direction, improve the capability of resisting high temperature, in order to meet the requirements of high power loudspeaker.
    3.Simple sizing process, stable assembly quality
    Development of UV, high performance, low odor of alpha cyanoacrylate glue, such as one component adhesive and at the end of coating type acrylic adhesive, anaerobic adhesive, simple application of adhesive technology, stable assembly quality and improve production efficiency.
    4.Gradually improve the environmental protection level of adhesive
    First eliminated containing toxic solvent adhesive, and then the elimination of solvent based adhesive developed solvent or water-based adhesive; and development of UV, VL and pre activated epoxy glue environmental protection, energy saving type adhesive; finally heating melt is environmentally friendly, energy-saving and easy to speaker decomposition and recovery of the adhesive.
    5.Development of adhesive for improving the acoustic performance of speakers
    At present, the development of speaker adhesive mainly consider the problem of adhesive bonding, the main is that the development of the adhesive is not enough to understand the acoustic performance of the adhesive, and the development of the adhesive is not enough.