What Is Reflective Material Made Of And Its Working Principle
Reflective material, also known as retroreflective material, is a material that can return light to the original path. The human eye identifies the position of the object and the shape and contour through the reflected light from the object. At night, when the light is weak, the visibility of the object is low, which increases the risk of driving at night. By studying the nocturnal emission phenomenon of cat’s eyes, people have developed retroreflective reflective materials.
Nowadays, reflective materials have been widely used in various road traffic safety facilities, such as traffic sign marking, protuberance road sign, contour mark, traffic cone, collision avoidance tube and so on, as well as car numbers, clothes and shoes, shoes and hats, firefighting, railway, water transportation, mining area and so on, which can be divided into traffic signs reflective material, road marking reflective material and protruding Road Standard, contours, reflective materials for clothing, etc.
Review of reflective film
According to the principle of retro reflection, the reflective material can make use of the illumination of the car lamp and the reflection of the light to “light” the front and improve the distance of the driver to find the object ahead, so that the driver can take appropriate measures for safe disposal at a more full time. Compared with other kinds of road traffic safety measures, compared with the cost of all kinds of road traffic accidents, the application of retroreflection technology is no doubt a low cost and effective solution. The application of the antireflective material is a more active safety precaution. It is safer and more valuable to the life by comparing with the measures aimed at reducing the degree of injury after the accident, such as guardrail protection.
Since the 1930s, in addition to the rapid use of a variety of antireflective materials created by science and technology industry, in order to reduce road traffic damage as soon as possible, the research on the application of retro reflection technology to improve road traffic safety conditions is gradually started.
Traffic sign reflective film
Reflective film is a kind of retroreflective material which can be directly applied to film, and is also the most widely used retroreflective material. In 1939, the Manual of United Traffic Control Devices officially stipulated that traffic signs should be constructed with reflective films.
Since then, with the development of chemical industry, especially synthetic resin, various R & D institutions have continuously studied and innovating, using glass bead technology, synthetic resin technology, film technology, and coating technology, a series of high-quality retro reflection products have been developed one after another.
In the 1940s, the original reflective film, called “engineering grade” reflective film, was widely used in road traffic signs. Since then, a series of products, such as reflective films for personal safety protection, such as clothing, have been developed. With the development of a series of materials technology and optical technology, especially the appearance of the micro prism reflective material, this kind of reflective material, which was originally used mainly for traffic signs, has been gradually updated.
Reflective materials list
In traditional habits, according to the structure of the reflective film reflector, the reflective film is divided into two categories, glass bead reflective sheeting and micro-prismatic reflective sheeting.
Glass bead type reflective film appears earlier, but its technological change is less, there are two main types, one is lens embedded reflective film, which is used as engineering class reflective film. One is a sealed capsule type, which is usually called high strength reflective film. It should be put off in the lens embedded reflective film for the application. Because of its long history, in the long production and manufacturing process, many kinds of reflective films have been made, such as Glass Beads High Intensity Reflective Sheeting, using the diameter of the lens, density and the thickness of resistance coating. The density of the glass bead is increased to improve some brightness. The reflective film, commonly known as the economic grade, is mainly produced in China. It is basically realized on the basis of the technology of the engineering grade reflective film, by reducing the quantity and density of the lens (glass bead), these two kinds of reflective films, and the Commercial Grade Reflective Sheeting, its reflection ability cannot meet the traffic. The need for safety is mostly used in the business field, and rarely in the world is included in the standard of traffic safety to light.
Association of Standard Testing of Materials is a long history of the material testing standards international organization, abbreviated as ASTM, its establishment is to provide a series of material testing standards to the scientific and industrial community to realize the definition of new materials and to provide a common communication for the world’s scientific community. The technical platform. Providing technical support for Testing Standardization for many materials in various industries, such as petroleum, natural gas, and chemical industry, for retroreflective materials.
In the ASTM4956’s reflective film standard, there are up to 11 kinds of reflective films and are still continuing; on the other hand, the ASTM standard is more like a product catalog about antireflective materials, rather than a standard to help understand the application and problems of the reflective film because of the initial classification of these materials at ASTM. The driver’s performance and needs were not considered.
For this reason, all developed countries, in order to provide more effective technical support and guidance to their own transportation engineering construction units, have set up their own national technical standards, instead of using the ASTM to classify the reflective materials.
Reflective film structure
Reflective film is a layer structure composed of multi-layer and different performance materials. Different reflective films have different layer structures.
It can be seen from the figure that the reflective film is usually a membrane structure consisting of layers of layers (protective film), reflection layer (functional layer), base (bearing layer), the adhesive layer and the bottom layer (protective layer). The surface layer of the reflective film is usually made of resin film with good transmittance and weatherability. The reflective layer is made up of different kinds of reflective film, including small glass beads, micro prismatic or metal reflective coating. The base is thin film made of resin organic compound, and the adhesive layer is generally epoxy resin. The bottom is the protective layer made of thick paper.
The primary function of reflective film is to improve the surface performance of traffic signs, so that they can adapt to the all-weather traffic needs and improve the safe operation conditions of roads.
Lens embedded (engineering grade) reflective film
The lens embedded reflective film, commonly known as “engineering grade”, is the first kind of glass bead reflective film, which is used in the industry as an “engineering grade” series of reflective films, which was invented in 1937. The term “engineering grade” is derived from the registered product name “Engineering Grade”, which is named after the invention company of the product. Later, many research institutions used the product name directly to represent the name of the experimental material, so the name was used in the world traffic engineering community, and its positive luminance (0.2 /-4) was generally below 100cd/lx/m. Until November 2008, a new prism type Engineering Grade Prismatic EGP Reflective Sheeting was developed according to the characteristics of the reflective luminance of the reflective film at the engineering grade.
Engineering grade reflective film back glue, generally divided into pressure sensitive type and heat sensitive two kinds, can complete paste. Using the same kind of ink, screen printing can also be used to print all kinds of patterns. The engineering grade reflective film is suitable for the aluminum plate, and the construction temperature is generally above 18 degree Celsius. If the temperature is too low, it will affect the performance of the viscose, resulting in the damage of the logo life.
The life span of engineering grade reflective film is usually 3~7 years, and the white membrane is 0.2 degrees /-4 (100cd/lx/m). The reflective film made of the same raw material has different life span under different climatic conditions.
The brightness stability, brightness intensity and weather resistance of engineering reflective films are some important bases for inspecting the quality of such reflective films. The cutting off of any link can reduce the cost of the product, but its quality will be greatly reduced, especially the gap between the weather resistance and the photometric parameters, which can obviously reflect the advantages and disadvantages of the reflective film at the engineering grade.
Lens sealed (high strength) reflective film
The lens sealed reflective film is a durable glass bead reflective film, called “high strength” reflective film, which was successfully developed in 1972. The “high-strength” comes from the English High Intensive Beads (HIB).
With the improvement of motor vehicle performance and road construction technology, the great changes in the urban environment, the rapid increase of Expressway and high-speed vehicle, the complex of urban light source and the endless bend of the road, have new requirements for the driver’s foresight to recognize the distance. Some shortcomings of high-strength grade reflective materials, especially in large angle reflective performance and processing technology and cost, have been unable to compare with the new prism technology, and gradually begin to be replaced.
In the second half of 90s, especially in twenty-first Century, the United States and Europe have launched the process of replacing high strength materials with prism materials.
Micro prismatic reflective film
The retro reflection principle of the micro prismatic reflective film is different from that of the engineering grade (lens embedded) and the high-strength grade (lens sealed) reflective film. The glass bead reflection principle is used in both the engineering and high strength reflective films, while the reflection principle of the micro prismatic reflective film is the refraction and reflection of the micro prismatic. The main representative products of the micro prismatic reflective film can be divided into four types: the truncated prism which pays attention to the long distance recognition, the close angle prism which pays attention to the near distance and the large angle, the high intensity prismatic with the distance recognition performance and the near distance reading performance, and the prism technology and the new material. A new prism reflective film with a combination of technology. They are complying with the diversification of application level, and new reflective materials that have emerged in recent years to meet different levels of needs.
LDP reflective sheeting
Long Distance Prismatic (LDP) is the first generation of micro prismatic reflective film, which came out in the early 1980s, and the first generation of diamond grade, crystal grade, star grade, are all these products.
When the vehicle moves into the discerning distance of the symbol, that is, under the large angle of view, the brightness of the first generation micro prismatic reflective film marks too much, so that the content of the logo cannot be read in the reading distance, or it takes longer to read. Thus, the large angle truncated micro prismatic is used to create a large angle truncated micro prismatic reflective film, so as to solve the problem of maintaining two degrees in the reading distance. Therefore, this kind of large angle reflective film is also a special prism reflective film which is described from the reflective performance.
VIP reflective sheeting
Compared with the reflector film of the long distance angle micro prismatic, the front brightness of the reflective film of the large angle truncated micro prismatic is low, but the brightness of its reflective light will not be greatly attenuated at the large angle of incidence and the angle of observation. The large angle is applied to the complex content that requires longer reading time. This reflective film is suitable for traffic signs of urban roads and wide roads. Although it has a general brightness at a long distance, its brightness is much higher than that of long distance reflectors at close range. Its direction is stronger than that of the long distance reflective film. It can be adjusted according to the location and direction of the sign to meet the needs of reading. VIP (Visual Impact Prismatic) came out in the late 1980s, and was once widely used. After the advent of all prism technology, it ceased production.
High Intensity Prismatic Reflective Sheeting
The High Intensity Prismatic (HIP) Reflective Sheeting is a prism reverse reflective material using the high intensity prismatic structure, which is to remove the non-reflective part of the traditional micro prismatic structure, so that the reflective film is all composed of the prism structure that can be fully reflected. It combines the two characteristics of the long distance and large angle micro prismatic reflective film, which is easy to find in keeping the front bright and long distance. It improves the high angle of incidence and the brightness under the observation angle at the distance of 50-250 meters.
The advent of the high intensity prismatic reflective film has broken through the academic barrier that the prism type reflective film cannot simultaneously take into consideration the ability of distant reflection and the ability to reflect light at close range. According to the path and mode of the vehicle light transmission, it finds the angle (incident angle and observation angle) needed in the ideal distance, and then determines the non-reflective region on the traditional angle micro prismatic, and then removes these non-reflective regions, thus the area of the reflective structure on the unit area reflector film is 100%, as well. It is the so-called “all reflective”.
Of course, this is only 100% of the theoretical reflection efficiency. In actual production, due to the restriction of material and other conditions, the brightness of reflected light cannot be achieved by 100%.
In the present high intensity prismatic reflective film, with each microcrystalline cube connected and arranged according to a certain regularity, there are more than 930 units on the area of a square centimeter of material to control the path of light in and reflected. The lower layer of microcrystalline cubic corner body is sealed to form an air layer, which makes use of the diffraction of light to form the internal full reflection of the incident light, so that the best anti light effect can be achieved without the use of the metal reflection layer. The reflective film made of polycarbonate and microcrystalline cube technology with high hardness and high hardness is compared with the traditional engineering grade and high intensity reflective film, and its reflective performance is not only multiplied, but also the performance of large angle reflection is also greatly improved. The positive luminance of the high intensity prismatic reflective film is more than six times that of the engineering grade, and the white film front brightness (0.2 /-4) is generally above 600 cd/lx/m, and is more than two times higher than the high strength grade, while the retro reflection performance of the large angle measurement angle (0.5 and 2) is about two to four times higher.
Application of high intensity prismatic reflective film
The high intensity prismatic reflective film is a traffic sign material suitable for all grade highways and urban roads, and gradually begins to replace the investment and consumption of logo lighting. When making road signs, if the long-term investment benefits and safety benefits are taken, the all prism reflective film can replace any grade of reflective film. Under normal use, the total prism luminance retention value after ten years is at least 80% of the initial brightness value, or ten years later, and it still can still greatly exceed the antireflective performance of the new high-strength and engineering level reflective films. At the same time, if you use the same kind of ink, combined with screen printing technology, you can make all kinds of traffic signs with patterns.
The high intensity prismatic reflective film is mainly used in finger mark, prohibition sign, warning sign and indication sign, especially the sign that needs long time reading, the symbol of complex visual environment, and the wide pavement and high grade highway, its performance is particularly outstanding. The diamond reflector film is suitable for the aluminum plate, and the operating temperature is generally above 18 degree Celsius.
In recent years, the prismatic type reflective film, in the case of no large changes in the structure, has turned the focus of innovation more to a variety of material processing techniques to achieve richer light control effects and rich material properties, so as to complete different Antireflective and flexible flexibility in order to adapt to different levels. The need. In the market, the reflective film, commonly known as “engineering grade prismatic”, “EGP”, prism type engineering grade (new super engineering grade), is a new form of prism reflective film. These reflective films have the same structure as the truncated prism, but the material processing technology is different, forming different reflective effects, superior weatherability and processing adaptability, in response to different application requirements.
Among them, especially the super class reflective film, because of meeting the needs of the market, it was rapidly popularized in early twenty-first Century. The original purpose of the design is to give full play to the advantage of the prism structure. On the basis of ensuring that it can surpass all the functions of the high-strength reflective film, it can also have better retro reflection performance and superior performance price ratio under the condition of multi angle.
These new prism reflective films have very high strength and thickness, which eliminate the defects such as easy tearing, wrinkling, bubble and surface honeycomb protuberance in the process of marking, greatly simplifying the difficulty of construction, making the processing process more easily controlled and reducing the loss caused by poor processing. At the same time, because the surface brightness factor of reflective film is large, the retroreflective performance is greatly improved. It not only has the superior inverse reflection coefficient in the long distance, but under the general recognition demand, the close range view still can keep the mark better, so that the driver can find the sign earlier and the content of the reading sign which is more clear in the near distance. Fig. 3 is a schematic diagram of the reflective structure of these prism structures. Through the difference of material processing on resin surface and cubic crystal surface, different retro reflection effects can be formed.
The surface of this kind of reflective film mostly uses polycarbonate, not only more wear resistance, resistance to scratch, but also can be matched with screen printing ink, can also be applied to heat transfer printing, making color traffic signs. At the same time, because of the improvement of surface brightness factor, the signs are more eye-catching and bright in the daytime, and also have better weather resistance.
Any enquires about our reflective materials, please feel free to contact us!