Applications of PMMA in Automotive Field

Acrylic is polymethyl methacrylate, abbreviated as PMMA, is a kind of polymer polymer made from methyl methacrylate polymerization, also known as organic glass, with high transparency, high weather resistance, high hardness, easy processing molding and other advantages, is often used as a substitute material for glass.

The relative molecular mass of PMMA is about 2 million, and the chain forming molecules is relatively soft, so the strength of PMMA is relatively high, and the tensile and impact resistance of PMMA is 7 ~ 18 times higher than that of ordinary glass. When it is used as plexiglass, even if it is broken, it will not burst like ordinary glass.

PMMA is currently the most excellent optical performance of transparent polymer materials, transmittance of 92%, higher than glass and PC transmittance, which has become the most important basic characteristics of many applications.

The weather resistance of PMMA is also second to none in common plastics, which is much higher than ordinary PC, PA and other plastics. In addition, the pencil hardness of PMMA can reach 2H, which is much higher than other ordinary plastics such as PC, and has good surface scratch resistance.

Because of its excellent characteristics, PMMA has been widely used in automotive, electronics and home appliances, consumer goods, lighting, construction and building materials, medical and other fields.

Applications of PMMA in Automotive Field

In general, PMMA in the car taillight, dashboard mask, outer column and decorative parts, interior lights, rearview mirror shell and other fields are applied, mainly used in the need for transparency, translucent and high gloss and other fields.

1, PMMA used in car taillights

Car lights are divided into headlights and taillights, and transparent materials are used for parts such as lampshades. Headlight and fog lamp shade use polycarbonate PC materials, this is because in the process of driving headlight use time is often relatively long, while the car driving on the lampshade impact resistance requirements are higher. But PC used for headlights also has the technology complex, high cost, easy aging and other shortcomings.

Taillights are generally turn signals, brake lights, light intensity is low, short service time, so the heat resistance requirements are relatively low, mostly using PMMA materials, PMMA transmittance 92%, higher than 90% PC, refractive index 1.492, good weather resistance, high surface hardness, is the taillight mask, reflector, light guide of the ideal material. Due to its high hardness, PMMA has good scratch resistance and can be used directly without surface protection when used as external light match mirror material. Light scattering PMMA has high scattering characteristics and is easy to achieve uniform lighting effect, which is one of the key materials in the current taillight application.

2, PMMA for dashboard mask

The dashboard mask mainly plays the role of protecting the instrument and displaying the instrument data accurately. Instrument panel mask is generally injection molded, PMMA is more used, with high transparency, enough strength, stiffness, good dimensional stability, in the solar radiation and engine waste heat under high temperature does not deformation, in long-term high temperature does not deformation, does not fail, does not affect the accuracy of the instrument.

3, Exterior columns and trim pieces

The car column is divided into ABC column, its performance requirements are mainly high gloss (generally piano black), high weather resistance, high heat resistance, scratch resistance, commonly used schemes are ABS+ spray paint, PP+ spray paint and PMMA+ABS double extrusion scheme, and toughened PMMA scheme. Compared with the spray painting scheme, PMMA can eliminate the spraying process, more environmentally friendly, lower cost, and gradually become the mainstream scheme.

4, PMMA is used for interior lights

Interior lights include reading lights and ambiance lights. Reading lights are part of a car’s internal lighting system, usually mounted on the front or rear roof. To prevent light pollution, reading lamps generally scatter light, using matte or frosted PMMA or PC solutions.

Atmosphere lamp is a kind of lighting that can create a comfortable atmosphere and enhance the sense of the vehicle. The light guide strips used in the ambient light are divided into two types: soft and hard according to their texture. Hard light guide texture is hard, can not bend, generally through injection molding or extrusion molding, material to PMMA, PC and other materials with transparency.

5, PMMA is used in the rear view mirror housing

The rear view mirror enclosure mainly requires high gloss and black brightness, while requiring high impact strength, scratch resistance and weather resistance. As the shape of the mirror shell is generally curved, it is easy to produce stress, so the machining performance and toughness are required to be relatively high. Conventional scheme has ABS spray painting, but the process pollution is serious, the process is many, the use of PMMA scheme can achieve spraying free, generally here to use toughened level of PMMA materials, to meet the test outline in the drop experiment and other projects.

The above is the routine application of PMMA in the automotive field, mainly related to optics or appearance, PMMA adds more possibilities to the automotive field.