前日有人咨询到摄像头用胶，我的第一反应还是停留在手机摄像模组的用胶点上，所以电话里沟通了半天也没有什么直观的印象。他告知我是铝合金和PC材质镜片的粘接，现在用的是环氧AB胶，目前碰到的问题是在经过低温时（放置在零下10度的冰箱）或发生脱落的现象，而且是批量的脱落。

由于电话里沟通不是很清楚，昨日我就到这个客户的现场去了一趟，看到了目前客户做的产品，请参看此图：

客户目前粘接的部位是镜片和底座，之前他们采用的是玻璃镜片，现在改用了PC材质的镜片，我看到他们的产品时第一反应就是应该用UV胶来实现的，果然，客户之前就是使用的UV胶，但是后来因为需要在整个镜头的外圈丝印一层黑色的膜，导致再进行镜片和底座的粘接时就无法用UV胶实现了。 目前客户使用的是环氧AB胶，我看了一下好像是东莞吉田盛夫公司的。 另外客户告诉我他们的铝合金底座上面氧化了一层，所以目前的问题就是用环氧AB胶粘接后（24小时常温固化）做高低温测试时低温会发生脱落现象。 目前客户也是从三个方面着手去解决，第一是让现有供应商提供其余粘接力更好的型号（去的时候他们也正在做一批产品做实验），第二是拿了一种溶剂（清洗剂、打底剂）对基座先做预处理再用AB胶粘接，第三就是用不氧化的底座做粘接实验。 目前貌似效果都不是很明显。

我给客户推荐的其实就是用于摄像模组的低温固化胶水（我个人估计价格客户肯定接受不了，呵呵），但权当一次实验也好。 此客户当时对他们的产品能否受热及耐温程度也没有任何概念， 后来就分别拿了两套产品进行实验，一个是使用摄像模组的低温固化胶水80度烘烤20分钟，另外使用普通的环氧粘接剂90度烘烤了45分钟，因为客户觉得不能超过100度烘烤。第二种胶其实做底填用途的，不过之前我在另外一个客户那里用作不锈钢和PCB板材的粘接效果非常不错（但那个是150度烘烤的）。  由于在客户那里实验做的比较仓促，后面从烘箱里拿出来冷却后就装成成品，放到他们的冰箱里面去了。

今天早上还没起床就接到了这个客户的电话， 说是做的两组产品都分别有一个发生了脱落现象，他们接下来或再多做一些样品看看效果。估计到周末就有进一步的结论。 到时候我在进一步续写吧，呵呵!

2012-04-08

关于此用胶点的后续，客户后来用我们的胶水又做了一个小批试验，结果依旧，有半数以上在低温老化后脱落。不过客户最终找到的一种方案据说是带有韧性的胶粘剂，即固化后韧性非常强（类似橡胶），所以即使低温情况下也依旧保持较强的粘接力。这里我考虑过CTE的匹配问题，但应该不是这个方面的原因，之前也碰到另外一个做喇叭磁芯粘接的客户用厌氧胶也出现低温下脱落的现象。但他们有一个共同点就是粘接物的体积都比较大，直径甚至达到10cm以上。 我印象中在一些电子领域的粘接，即使承受零下二十到零上100多度的冲击，也不至于会造成脱落的情况，是不是因为粘接体积和面积较小受影响比较小呢？这个就没研究过了！

后来有位网友给我推荐PU类型的胶粘剂来解决此方案，回头有空可以提供给客户尝试一下，顺便再到客户那里看看他们到底用的什么胶粘剂解决的问题！

近日有个做音圈的客户使用乐泰3106做中心胶用途，据反映感觉粘接力不太够而且觉得硬度也不够。 给其推荐了两款产品重新尝试，在乐泰官网下载了这份TDS资料，摘录如下，感兴趣的朋友可以去下载PDF版本：

PRODUCT DESCRIPTION
LOCTITE® 3106™ provides the following product
characteristics:
Technology Acrylic
Chemical Type Acrylated urethane
Appearance (uncured) Transparent liquidLMS
Components One component – requires no mixing
Viscosity Medium, thixotropic
Cure Ultraviolet (UV)/ visible light
Cure Benefit Production – high speed curing
Application Bonding
Flexibility Enhances load bearing & shock
absorbing characteristics of the bond
area.
LOCTITE® 3106™ is primarily designed for bonding rigid or
flexible PVC to polycarbonate where large gap filling
capabilities and flexible joints are desired. The product has
shown excellent adhesion to a wide variety of substrates
including glass, many plastics and most metals. The thixotropic
nature of LOCTITE® 3106™ reduces the migration of liquid
product after application to the substrate.
TYPICAL PROPERTIES OF UNCURED MATERIAL
Specific Gravity @ 25 °C 1.08
Refractive Index 1.48
Flash Point – See MSDS
Viscosity, Brookfield – RVT, 25 °C, mPa·s (cP):
Spindle 4, speed 20 rpm 3,500 to 7,500LMS
TYPICAL CURING PERFORMANCE
LOCTITE® 3106™ can be cured by exposure to UV and/or
visible light of sufficient intensity. To obtain full cure on
surfaces exposed to air, radiation @ 220 to 260 nm is also
required. The speed of cure will depend upon the UV intensity
and spectral distribution of the light source, the exposure time
and the light transmittance of the substrates.
Stress Cracking
Liquid adhesive is applied to a polycarbonate bar 6.4 cm by
13 mm by 3 mm which is then flexed to induce a known stress
level.
Stress Cracking, ASTM D 3929, minutes:
7 N/mm² stress on bar >15
12 N/mm² stress on bar 13 to 14

Fixture Time
Fixture time is defined as the time to develop a shear strength
of 0.1 N/mm².
UV Fixture Time, Glass microscope slides, seconds:
Black light, Zeta® 7500 light source:
6 mW/cm², measured @ 365 nm ≤15LMS
UV Fixture Time, Polycarbonate to PVC, seconds:
Metal halide bulb, Zeta® 7400:
30 mW/cm², measured @ 365 nm, <5
Electrodeless, H & V bulbs:
50 mW/cm², measured @ 365 nm, <5
Electrodeless, D bulb:
50 mW/cm², measured @ 365 nm, <5
Depth of Cure vs. Irradiance (365 nm)
The graph below shows the increase in depth of cure with time
at 50mW/cm² – 100mW/cm² as measured from the thickness
of the cured pellet formed in a 15mm diameter PTFE die.
Note: When exposed to a V Bulb at irradiances of 50 and 100
mW/cm² for 30 seconds, a depth of cure greater than 13 mm
was achieved. The performance for medium pressure Hg will
be similar to Electrodeless system, H bulb

TYPICAL PROPERTIES OF CURED MATERIAL
Cured @ 30 mW/cm², measured @ 365 nm, for 80 seconds using
a glass filtered metal halide light source
Physical Properties:
Shore Hardness, ISO 868, Durometer D 53
Refractive Index 1.5
Water Absorption, ISO 62, %:
2 hours in boiling water 3.18
Elongation, at break, ISO 527-3, % 250
Tensile Modulus, ISO 527-3 N/mm² 255
(psi) (37,000)
Tensile Strength, at break, ISO 527-3 N/mm² 18.6
(psi) (2,700)
Electrical Properties:
Surface Resistivity, IEC 60093, Ω∙cm 9.2×1014
Volume Resistivity, IEC 60093, Ω·cm 7.7×1014
Dielectric Breakdown Strength, , kV/mm 26
Dielectric Constant / Dissipation Factor, IEC 60250:
100-Hz 5.17 / 0.04
1-kHz 5.01 / 0.02
1-MHz 4.61 / 0.04
TYPICAL PERFORMANCE OF CURED MATERIAL
Adhesive Properties
Cured @ 30 mW/cm², measured @ 365 nm, for 80 seconds using
a metal halide light source, (samples with 0.5 mm gap).
Lap Shear Strength, ISO 4587:
Polycarbonate N/mm² *5.2
(psi) (750)
* substrate failure

TYPICAL ENVIRONMENTAL RESISTANCE
Cured @ 30 mW/cm², measured @ 365 nm, for 80 seconds using
a metal halide light source, (samples with 0.5 mm gap).
Lap Shear Strength, ISO 4587:
Polycarbonate:
0.5 mm gap
Chemical/Solvent Resistance
Aged under conditions indicated and tested @ 22 °C.
% of initial strength
Environment °C 2 h 24 h 170 h
Boiling water 100 * 100 ——– ——–
Water immersion 49 * 100 ——– ——–
Water immersion 87 * 100 ——– ——–
Isopropanol immersion 22 ——– 95 ——–
Heat/humidity 38 ——– ——– * 100
Heat Aging
Lap Shear Strength, ISO 4587, % of initial strength:
Polycarbonate:
Aged @ 71 °C for 170 hours *100
Aged @ 71 °C for 340 hours *100
Aged @ 93 °C for 170 hours *100
Aged @ 93 °C for 340 hours *100
* substrate failure
GENERAL INFORMATION
This product is not recommended for use in pure oxygen
and/or oxygen rich systems and should not be selected as
a sealant for chlorine or other strong oxidizing materials.
For safe handling information on this product, consult the
Material Safety Data Sheet (MSDS).
Where aqueous washing systems are used to clean the
surfaces before bonding, it is important to check for
compatibility of the washing solution with the adhesive. In
some cases these aqueous washes can affect the cure and
performance of the adhesive.
This product is not normally recommended for use on plastics
(particularly thermoplastic materials where stress cracking of
the plastic could result). Users are recommended to confirm
compatibility of the product with such substrates.
Directions for use
1. This product is light sensitive; exposure to daylight, UV
light and artificial lighting should be kept to a minimum
during storage and handling.
2. The product should be dispensed from applicators with
black feedlines.
3. For best performance bond surfaces should be clean and
free from grease.
4. Cure rate is dependent on lamp intensity, distance from
light source, depth of cure needed or bondline gap and
light transmittance of the substrate through which the
radiation must pass.
5. Recommended intensity for cure in bondline situation is 5
mW/cm² minimum (measured at the bondline) with an
exposure time of 4-5 times the fixture time at the same
intensity.

6. For dry curing of exposed surfaces, higher intensity UV is
required (100 mW/cm²).
7. Cooling should be provided for temperature sensitive
substrates such as thermoplastics.
8. Crystalline and semi-crystalline thermoplastics should be
checked for risk of stress cracking when exposed to liquid
adhesive.
9. Excess adhesive can be wiped away with organic solvent.
10. Bonds should be allowed to cool before subjecting to any
service loads.
Loctite Material SpecificationLMS
LMS dated April-22, 2002. Test reports for each batch are
available for the indicated properties. LMS test reports include
selected QC test parameters considered appropriate to
specifications for customer use. Additionally, comprehensive
controls are in place to assure product quality and
consistency. Special customer specification requirements may
be coordinated through Henkel Quality.
Storage
Store product in the unopened container in a dry location.
Storage information may be indicated on the product container
labeling.
Optimal Storage: 8 °C to 21 °C. Storage below 8 °C or
greater than 28 °C can adversely affect product properties.
Material removed from containers may be contaminated during
use. Do not return product to the original container. Henkel
Corporation cannot assume responsibility for product which
has been contaminated or stored under conditions other than
those previously indicated. If additional information is required,
please contact your local Technical Service Center or
Customer Service Representative.
Conversions
(°C x 1.8) + 32 = °F
kV/mm x 25.4 = V/mil
mm / 25.4 = inches
μm / 25.4 = mil
N x 0.225 = lb
N/mm x 5.71 = lb/in
N/mm² x 145 = psi
MPa x 145 = psi
N·m x 8.851 = lb·in
N·m x 0.738 = lb·ft
N·mm x 0.142 = oz·in
mPa·s = cP

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最近在学习UV胶的一些资料，发现对于UV胶的固化条件有几种不同的表达方式，其中一种是以需要能量的总和，以mJ/cm2表示，另外一种是以mW/cm2加照射时间的方式表示，其实两者之间是有一定的换算关系的，其中以UV光源功率简单的乘以照射时间就可以得出所需要的能量。其实我觉得这个和UV胶的施胶量也是应该有关系的，有些资料会标识出UV胶的表干时间以及完全固化时间，当然有些还会标识UV胶能够得到的固化深度，这个可能在做灌封用途中会比较关注。在网上找了篇文章是大概解释UV能量单位换算关系的，摘录如下：

UV能量计单位转化，紫外线强度单位

1mw/cm2 X 1s = 1mj/cm2(1毫瓦/1平方厘米X 1秒=1毫焦/平方厘米)
由于UV紫外照度数据显示测试时的最高UV照度（强度）值+ mw/cm2，
如果简单化地以+UV照度mw/cm2 X时间(秒)推算UV能量 mj/cm2,
通常会大于实际的累积能量值，您需要对于具体的应用领域作出选择。