Self-adhesive films for wide-format printed graphics are everywhere today. With a broad range of options available to the sign industry, it is important to understand how to select the right material for each job and, if necessary, how to protect it with an overlaminate or clearcoat for enhanced durability.
如今自粘膜在宽幅印刷图形的保护方面起到了非常重要的作用。随着标识行业日益广泛的选择，了解如何为每个项目选择合适的产品以及必要时如何选择合适的覆膜材料和增加透明涂层来保护产品以提高产品的耐用性至关重要。
The first step is to understand the client’s intentions for a given graphic application. Pressure-sensitive materials have diversified in their construction along with the applications where they are put to use, from typical signage and graphics to wraps for cars, trucks, trailers, buses, railcars, watercraft and even airplanes. Signmakers need to look through product catalogues and other resources for technical information before selecting the best option.
因此首先需要了解客户对于图形产品的应用有哪些需求。压敏材料的应用方式以及应用场合都非常广泛，从典型的标识和印刷图形包装到汽车、卡车、拖车、公共汽车、地铁、船舶甚至飞机的包装均有相关应用涉及。在做出最佳选择之前，标志制造商需要通过查阅产品目录和其他资源以获取技术信息。
There is all too real a risk of the client misunderstanding the possibility of adhesive instability, the fading of printed colours or the inability to remove a graphic cleanly after time, so it is very important to discuss all of these matters upfront.
部分客户可能会对粘合剂的稳定性持怀疑态度，印刷图形颜料的褪色以及在使用后无法完全干净地清除图形，这些都是非常现实的问题，所以事先对这些问题进行讨论是非常有必要的。
Base films
基膜的选择
The main components of a pressure-sensitive substrate are the base film, the adhesive and the liner. The following are the most popular base film options and their attributes:
压敏衬底的主要组件是基膜、粘合剂和衬垫。以下是最流行的几种基膜的选择及其属性：
Acrylic—Excellent clarity, rigid construction, excellent chemical resistance, moderate price.
亚克力——透明度高，结构坚固，耐腐蚀性强，价格适中。
Polyester—Good clarity, rigid construction, fair to good chemical resistance, high price.
聚酯——透明度高，结构坚固，耐腐蚀性良好，价格昂贵。
Polyethylene (PE)—Good clarity, semi-flexible to soft construction, good to excellent chemical resistance, low price.
聚乙烯（PE）——透明度高，半柔性结构，耐腐蚀性较好，价格低廉。
Polypropylene (PP)—Good clarity, semi-rigid construction, excellent chemical resistance, moderate price.
聚丙烯（PP）——透明度高，半刚性结构，耐腐蚀性强，价格适中。
Polyvinyl chloride (PVC)—Good clarity, flexible to soft construction, fair to good chemical resistance, moderate price.
聚氯乙烯（PVC）——透明度高，半柔性结构，耐腐蚀性良好，价格适中。
Polyurethane (PU)—Good clarity, flexible to soft construction, good chemical resistance, very high price.
聚氨酯（PU）——透明度高，半柔性结构，耐腐蚀性较好，价格昂贵。
Among these, the most commonly used is PVC. Indeed, it has become the industry standard for signs and graphics. There are two primary categories of PVC films for digital wide-format printing, based on the two ways they can be manufactured: calendered and cast.
其中，最常用的是PVC材料。事实上，它已经成为标识和图形行业的标准用材。针对数字宽幅印刷，PVC薄膜主要有两种制作方式：压延和浇铸。
Making a calendered film can be compared to making a pizza (see Figure 1). First, a mixer is used to blend PVC with a plasticizer and other additives—such as dyes, oils and stabilizers—to achieve the desired attributes. Next, an extruder blends these raw materials further. Finally, the resulting mixture is fed through heated calender rollers, rotating in opposite directions. These rollers generate sufficient pressure and heat to flatten the mixture into a uniform film. As the film passes through more rollers, it is made thinner.
压延薄膜的过程看参见图1。首先，使用混合器将PVC材料与塑化剂和其他添加剂（如染料、油和稳定剂）混合，获得所需的材料属性，接下来，挤出机进一步将这些原材料混合，最后，所得到的混合物通过加热的压延辊进行压制，向相反的方向旋转，这些滚筒产生足够的压力和热量将混合物压成均匀的薄膜。当薄膜通过更多的滚筒时，它就会变得更薄。
Making a cast film, on the other hand, is more like making a pancake (see Figure 2). A liquid mixture of polymers is extruded to form a thin sheet of film, which is then vacuum-pinned to the surface of a cooled roll for winding. A carrier web brings it through an oven and then it is wound up on a roller.
浇铸薄膜的制作过程参见图2。将聚合物的液体混合物挤出以形成薄片薄膜，然后将其真空固定到冷却辊的表面并卷绕。传输系统将其传输通过烘箱，然后将其卷绕在滚筒上。
Calendered films typically are 0.08 to 0.1 mm (3 to 4 mil) thick and do not need any premask tape. There is a high risk of shrinkage after application and they can offer poor conformability, but they are relatively easy to remove afterwards. Durability is often five years or less.
压延薄膜的厚度通常为0.08至0.1毫米（3至4密耳），不需要任何覆贴膜。应用后薄膜表面容易收缩，并且它们的适应性差，但是它们在使用过后相对容易清除，保质期通常在五年或五年以内。
Cast films, on the other hand, are usually about 0.05 mm (2 mil) thick and require premask tape. Their risk of shrinkage after application is low and they conform well to installation surfaces. They are not as easy to remove, but they can last five years or more.
浇铸薄膜厚度通常约为0.05毫米（2密耳），需要覆贴膜辅助。它们在应用后不易收缩，并且能与安装表面达到几乎完美的吻合状态，但它们不易清除，保质期在五年或者五年以上。
Some films are used in conjunction with application tape, which has several purposes. It adds stiffness, aids in the registration of cut graphics, helps prevent the film from stretching and protects the graphics from getting scratched during the application process. It also protects printed graphics from damage during shipping and handling.
有些薄膜和应用型胶带结合使用有以下几点好处。首先这样增加了薄膜硬度，有助于方便图形切割和防止薄膜的拉伸变形，并保护图像在使用过程中不被划伤。同时，它还可以保护印刷图形在运输和处理过程中免受损坏。
Buses, watercraft and even airplanes can be wrapped with self-adhesive films.
公共汽车，轮船甚至飞机可以用自粘膜来进行包装。
Adhesives
粘合剂
The two primary types of adhesive are pressure-sensitive and pressure-activated.
两种主要类型的粘合剂是压力敏感胶和压力活力胶。
A pressure-sensitive adhesive (PSA) will stick to the surface upon contact, whereas a pressure-activated adhesive (PAA) can slide along the surface and be repositioned until the installer applies firm pressure to it. A PSA is suitable for a flat surfaces and simple curves, is usually applied ‘wet’ and requires greater skill on the installer’s part. A PAA is preferable when tackling compound curves, is usually applied ‘dry’ and can be used by installers of all skill levels.
压力敏感胶（PSA）在接触材料时会直接粘附在材料表面上，而压力活力胶（PAA）可以使薄膜沿着表面滑动并随机定位，直到安装者施加一定压力才会牢牢粘附在材料表面。PSA适用于表面平滑和曲线简单的材料，通常应用于潮湿的环境中，并且对安装人员的安装技术要求较高。处理曲线复杂的材料时最好使用PAA，它通常应用于干燥的环境之中，只要安装人员技术达标就可以进行覆膜工作。
For certain applications, such as fleet graphics for box trucks, some installers do not want the slideability of a PAA, but instead prefer the opportunity to tack the film right where they want it to be upon first contact. Their margin for error is very limited, but as expert installers, they prefer this challenge over the way a slideable adhesive behaves.
针对某些现实应用情况（如箱式货车的车队图形），一些安装人员就不喜欢PAA的可滑动性，他们更喜欢在第一次覆膜时就将薄膜粘合到他们想粘合的位置。而材料留给安装人员的误差空间极其有限，所以作为专业安装人员，他们更喜欢滑动粘合的方法。
In most other cases, installers enjoy the extra freedom offered by slideability. And when they are tackling the complex curves and deep channels of most vehicles, it is necessary.
在大多数情况下，滑动黏合的方法给安装人员带来了更多的安装自由。当他们对大多数车辆复杂的曲线和深槽进行处理时，滑动粘合的方法更为合适。
Different surface materials will also exhibit different levels of affinity for an adhesive. ‘Peel’ combines the effects of this surface affinity and the level of energy dissipation dictated by the adhesive’s rheology (i.e. flow). Hence, the same film will peel differently from Different materials.
不同的表层材料和粘合剂配合程度也不一样。“剥离”技术将这种表层粘附力的效果和取决于粘合剂流变性（即流动能力）的能量消耗水平结合起来。因此，即使是相同的薄膜，把它从不同的材料表面上剥离下来的方法也会不同。
A heat gun helps stretch the film across compound curves.
热风枪的热量有助于薄膜在复合曲线上进行拉伸。
To achieve a strong installation, it is best to choose an adhesive and a surface based on their mutual compatibility. The adhesive should have a lower surface energy than that of the material to which it will be applied. And if the material is modified by cleaning and roughing it, it will provide for stronger bonding at its surface.
为了实现安装最终的牢固性，我们最好根据粘合剂和表层材料的相互兼容性来进行选择。粘合剂的表面能应低于它将要覆涂的材料的表面能。如果通过清洁和粗加工来对材料进行改进，它的表面将提供更强的粘合性能。
Of course, the highest level of adhesion is not always desirable. A permanent adhesive is not intended for removal, so if there is a need to change out the graphic later on, it may be very difficult, even with heat, chemicals and tool. In some instances, more than 30 per cent of the adhesive could be left behind as residue.
当然，粘合得过于牢固并不一定是好事。永久型的粘合剂非常难以清除，如果之后要对图形进行更换，那么即使是在使用热量、化学物质或工具的辅助下，清除也会非常困难。在通常情况下，即使认真清除过后，依旧会有超过30％的粘合剂残留物留下。
A removable adhesive, on the other hand, may provide a medium to high level of tack, may be easily removable with heat and/or chemicals and may leave behind less than 30 per cent residue. And a changeable or ‘ultra-removable’ adhesive could prove even easier, providing medium tack, requiring little to no heat for removal and leaving behind little to no residue.
另一方面，可移除的粘合剂可以提供中等至高水平的粘性，可以容易地通过加热或化学物质清除，并且遗留的残留物少于30％。可更换或“超可清除”的粘合剂可以提供中等粘性，几乎不需要加热即可清除，留下很少或几乎没有残留物。
It is also important to note adhesion builds over time and with exposure to the elements. For this reason, an adhesive film left on a surface for longer than its warranted durability may become extremely difficult to remove.
注意产品黏合期限和放置的环境也非常重要。出于这个原因，当薄膜在产品的表面覆膜的时间长于保质期时，薄膜就容易变得非常难以清除。
Typically, graphic film manufacturers test their products for durability and weatherability across different climates and for varying periods of exposure. So, in general, signmakers should not need to test the materials in the same ways themselves. That said, surface adhesion test kits are available for checking the compatibility of a film and adhesive with a given surface.
通常，图形薄膜制造商在不同气候和不同曝光放置周期下测试产品的耐用性和耐候性。所以，标识制造商就不需要自己以相同的方式来测试材料了。表面附着力测试工具可用于检查薄膜和粘合剂与指定产品表面的相容性。
Light management
薄膜对光源的影响
Clear, translucent and perforated films offer a variety of light management properties for signs and graphics.
透明、半透明和穿孔的薄膜能够适应不同标识和图形的发光特点。
Many sign faces use a clear or milky white translucent plastic film with a front and back surface, such that the light source is installed behind the back. In other cases, a multi-layered approach is taken, with light passing through a diffuser film, a clear rigid sign face and a translucent colour film. The diffuser film can help mask ‘hot spots’ created by the spacing and layout of the light-emitting diodes (LEDs), to create more uniform illumination of the sign face.
许多标识的正面和背面都会使用透明或乳白色半透明塑料薄膜，而光源则安装在背面。另外，采用多层覆膜的方法，清晰的标识面和半透明彩色薄膜得以完美地相互配合，使光线通过漫反射的原理来使标识发光。漫反射膜可以帮助掩盖由于LED间距和布局的原因所产生的“热点”，从而使标识面得到更均匀的照明。
With dual-colour films, a sign can appear different by day and night. A channel letter populated by white LEDs and treated with a light enhancement film can be augmented with a diffuser film, translucent colour film, clear film and perforated dual-colour film. By day, the non-illuminated sign exhibits the perforated film’s colour in reflected light. By night, it is backlit by the LEDs and visually transforms into the colour of the translucent film. By way of example, black letters on a white background, which are highly visible in daylight, can become bright blue letters on a dark background at night. And the light management properties of translucent films mean white LEDs can be ‘tuned’ to create other colours as desired.
通过使用双色薄膜，标识可以在白天和夜晚呈现出不同的状态。由白光填充的LED发光字若想增强其亮度，可以通过扩散膜、半透明彩色膜、透明薄膜和穿孔双色薄膜来增强。白天，非照明标识在反射光中呈现穿孔膜的颜色，到了晚上，它通过LED背光照明的功能发光，并从外表上转换成半透明薄膜的颜色。举例来说，当处于白天时，黑色字母在白色的背景上是非常显眼的，当处于夜晚时，明亮的蓝色字母在深色背景上就非常的明显。而半透明薄膜的光管理特性意味着白光LED可以根据需要来调整以显示其他颜色。
Specialty overlaminates are formulated with different applications and needs in mind, such as graffiti resistance for posters and cleanability for window graphics.
专业覆膜是根据不同的应用和需求定制的，例如海报的抗涂鸦性和窗面图形的自洁能力。
Graphic protection
图形的保护
As mentioned, the durability of graphics can be enhanced by applying an overlaminate or a clearcoat, to protect against dirt, contaminants, colour fading from ultraviolet (UV) radiation, vandalism and other potential causes of damage. Such an application can add new properties, such as skid and abrasion resistance and cleanability.
如前所述，我们可以通过覆膜和增加透明涂层来增强图形的耐用性，减少污垢和污染物对图形的污染，防止由紫外线（UV）辐射引起的图形颜色的衰减和其他造成损害的潜在原因。这样的应用也增加了新的性能，例如防滑性、耐磨性以及可清洁性。
It is worth keeping in mind not all graphics require protection. Another reason to laminate or clearcoat graphics, however, is for visual enhancement, as their gloss level, either to reduce glare or to add shine.
值得注意的是，并非对所有图形都要进行保护措施。为图形覆膜或增加透明涂层的另一个原因是为了增强视觉效果，因为它们本身的光泽度可以减少刺眼的眩光增加图形本身的光泽感。
Overlamination uses a cold or hot-roll laminator, is compatible with digitally printed graphics and can achieve an ultra-matte, matte, lustre, gloss or high-gloss finish. Specialty overlaminates are often formulated with many different applications in mind, such as car wraps, window graphics, flexible sign faces, awnings, wall murals and box truck graphics.
表层覆膜使用冷辊或热辊层压机，与数字印刷图形兼容，可实现超哑光、哑光、光泽以及高光泽度。专业覆膜通常会涉及到许多不同的应用，例如汽车包装、窗口图形包装、柔性标识包装、遮阳篷包装、仓栅式货车装饰图形包装。
The process of overlamination adds stiffness for greater ease of installation and supports special optional features like graffiti resistance, slip resistance (usually necessary for floor graphics) and cleanability. The cost ranges from medium to high, depending on the laminator type and model.
薄膜的覆盖增强了图形的硬度，更易于安装并且拥有了更多性能，例如涂鸦抗性、防滑性和可清洁性。层压机的型号和运作模式也会决定成本的高低。
Clearcoating requires the use of screenprinting equipment, though it is compatible with both screenprinted and digitally printed graphics. Only three finishes are possible—matte, lustre and gloss—and no stiffness is added to the graphics, but the cost is very low compared to lamination.
增加透明涂层需要使用丝网印刷设备，尽管它均可与丝网印刷和数字印刷图形兼容。透明涂层的三种类别分别是哑光、光泽和高光泽，它不能增加图形硬度，但是与覆膜相比，它的成本非常低。
Reflective sheeting is useful for nighttime visibility.
反光板对于提高夜间能见度起到了很大的作用。
Adhesive-backed films have enabled a virtually unlimited breadth of options for surface imaging and customization, both for branding and decor applications. Understanding base films, adhesives, light management films and finishing options is important for today’s signmakers, so they can consistently choose the best products over time for a variety of projects.
无论是品牌还是装饰应用，背胶粘贴膜都可以实现宽幅图像的多种表面成像和定制选项。了解基础薄膜、粘合剂、薄膜的光线管理和最后的加工选择对于如今的标识制造商而言非常重要，在充分了解相关知识之后，他们可以随时为各种项目选择最佳产品。
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