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Light-emittnig diode mark and its used semi-transparent plastic sheet

A light-emitting diode, translucent technology, applied in the field of LED signs, can solve problems such as deviation and excessive slack of the gauge sheet

Inactive Publication Date: 2004-01-21
ATOFINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, when the sheet is embossed to form a pattern, the thicker gauge sheet tends to relax considerably and thus deviates further from the original embossed pattern

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0053] The particle layer can be prepared by melt-mixing the particles in an amount of 1-60%, preferably 10-50%, with a thermoplastic matrix.

[0054] Melt mixing is well known in the industry, and one example of a method of making an article of the invention is as follows: After drying the thermoplastic matrix resin in a dehydrating, forced-air oven, it is passed through, for example, a Single-screw extruder and cross-linked granulate compounding. Compounding can also be carried out using a twin-screw extruder equipped with a vacuum degassing system. Pellets, matrix resin and additives are fed into the feed hopper of the extruder through separate feeders. The particle conveying system should be a closed system to avoid safety hazards and dust hazards. The pellets are metered into the feed hopper of the extruder using a feeder with a twisted screw by gravimetric control or volumetric control. When the composition contains 1-60% dispersed particles and 40-99% thermoplastic m...

Embodiment 1

[0092] flakes with two layers

[0093] Preparation of granular layer (composition x)

[0094] Cross-linked particles containing 96% methyl methacrylate / 4% ethyl acrylate copolymer and allyl methacrylate as a cross-linking agent were melt mixed at 40% by weight in a molded acrylic resin (methacrylic acid In methyl ester / ethyl acrylate=96 / 4), described particle is spherical substantially, and average particle diameter is about 10-32 micron, and wherein its diameter of 90% by weight particle is less than 40 micron, and refractive index (n D ) is 1.4907. The refractive index (n D ) is 1.4935, measured according to ASTM D 542. Therefore, the refractive index of the particles differs by 0.002 units compared to the acrylic matrix.

[0095] Preparation of granular layer (composition y)

[0096] Crosslinked particles containing 74.3% methyl methacrylate, 24.8% styrene, and 0.9% allyl methacrylate as a crosslinking agent were melt mixed at 40% by weight in a molded acrylic resi...

Embodiment 2

[0120] Sheet products with multiple layers

[0121] The following are examples of materials fabricated using the three-layer coextrusion technique. Two extruders were used (A = primary extruder, B = secondary extruder). The resin extruded from the primary extruder was used as the A layer, and the resin extruded from the secondary extruder was used as the B layer. Flake samples were fabricated with an "ABA" layer structure. In Example 3a, a reference sheet for these experiments was made by feeding a standard red acrylate resin through these two extruders.

[0122] Tables V-A show that the standard red acrylate sample (Example 3a) and the coextruded red samples (Examples 3b-f) have approximately the same light transmittance and transmitted color values. Table V-B shows that the upper surface of the coextruded samples had about the same gloss and reflective color values ​​as the upper surface of the standard acrylate sample.

[0123] Examples 3a-f contained pigment in the b...

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PUM

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Abstract

Disclosed is a polished translucent co-extruded sheet having utility as a light diffusing protective cover or sign face for light emitting diode (LED) light sources and other purposes. The sheet is comprised of (a) a particle layer containing particles having a mean particle size of about 4 to 100 microns and having a particle size distribution of between 1-110 microns, at a loading of 1 to 60% melt blended with a thermoplastic matrix, wherein the particle and matrix have refractive indices that differ by greater than 0.001 units of each other when measured in conformance with ASTM D 542; and (b) at least one substrate layer comprised of thermoplastic compositions, wherein the substrates have a refractive index within 0.2 units of the refractive index of the particle layer matrix when measured in conformance with ASTM D 542.

Description

[0001] This application claims priority to US Patent Provisional Application No. 60 / 383,228 (filed May 23, 2002) and Provisional Application No. 60 / 438,611 (filed January 8, 2003). technical field [0002] The present invention relates to translucent, coextruded thermoplastic sheets that can be used as light diffusing protective films or sign fluorescent surfaces for Light Emitting Diode (LED) light sources and other uses, as well as LED signs using such sheets. technical background [0003] The most common plastics used for the fluorescent surfaces of illuminated signs and signal letters are acrylic and polycarbonate plastics. Acrylics are typically used when high light transmission, good weatherability and / or yellowing resistance are required. Polycarbonate is often used when high impact resistance, heat resistance and flame retardancy are required. In many of these uses, the plastic is pigmented to achieve the desired color and light transmission properties. [0004] Th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B32B5/16B32B7/023C09K17/52G09F9/33G09F13/12H05B33/00
CPCB32B7/02Y10S428/917C09K17/52B32B5/16Y10T428/26Y10T428/254Y10T428/24942Y10T428/249921B32B7/023G02B5/02
Inventor J·J·赖利P·J·基廷R·R·德克斯
Owner ATOFINA