KR20170099361A - Light Diffusion Plate Composition of Crystalline Resin - Google Patents

Abstract

The present invention relates to a crystalline resin light diffusing plate composite which is capable of having excellent brightness characteristics by being made of a crystalline resin, and having high flatness by suppressing warpage deformation during extrusion. According to the present invention, the crystalline resin light diffusing plate composite comprises: 0.1-1.2 wt% of an organic nucleating agent; 0.3-1.9 wt% of a light diffusing agent; 0.5-20 wt% of an anti-deformation agent formed of inorganic particles; 0.1-2.8 wt% of other additives; and the remaining of the crystalline resin having crystallinity of 45-70% on the basis of room temperature of 25C.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a light diffusing plate composition,

More particularly, the present invention relates to a light diffusing plate which is made of a crystalline resin such as polypropylene and which has a haze of 20% or more and has high optical efficiency, To a crystalline resin light-diffusing plate composition.

The light diffusion plate is a transparent or translucent light-transmissive light cover that diffuses light emitted from a lighting device such as a fluorescent lamp or a light emitting diode and exits the light diffusion plate. The light diffusing plate may have a thin film adhered to the surface of the light diffusing plate, such as a picture, a phrase, a graphic, or the like, or may have a specific letter or picture shape.

In addition to the advertisement device, a light diffusion plate is also used for an illumination device such as a fluorescent lamp or a stand, a street light, an interior lighting, etc. Also, a back light unit (BLU) of a liquid crystal display A light diffuser plate is used.

These conventional optical diffusing plates are fabricated by adding polymeric particles partially crosslinked with inorganic particles, styrene-based polymer, acrylic polymer particles, or the like as a diffusing agent to the main material of the optical diffusion plate.

Korean Patent Laid-Open Publication No. 2010-0102906 discloses a composition for a light diffusion plate using a polypropylene resin. The composition for a light diffusion plate of this patent publication is composed of a random polypropylene resin, an impact polypropylene resin, and a light diffusing agent, and has a low cost and excellent light resistance so that yellowing does not occur and light transmittance and light Thereby realizing a light diffusion plate having excellent diffusibility and high luminance.

However, the conventional polypropylene resin, which is a crystalline resin, has a problem in that the conventional light diffusing plate using a polypropylene resin is not suitable for a light diffusing plate which has a high shrinkage ratio and is warped in an extrusion molding process and requires high flatness .

Conventionally, an amorphous resin such as polystyrene (PS) or polycarbonate (PC) having a shrinkage ratio of 0.5% or less has been used to produce a light diffusing plate having high flatness. However, the amorphous resin is a resin having a molecular size smaller than the wavelength of visible light It has a high transparency with a haze of 15% or less because of the small interference of the visible light ray, and thus there is a disadvantage that a hot spot is generated when the LED light is used for a strong direct-current LED light source.

Korean Registered Patent No. 10-1219602 (Registered on Mar. 01, 2013) Korean Registered Patent No. 10-1448897 (Registered on October 1, 2014)

It is an object of the present invention to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a crystalline resin optical fiber having excellent brightness characteristics and suppressing warpage distortion upon extrusion, To provide a diffusion plate composition.

In order to achieve the above object, the crystalline resin light diffusing plate composition according to the present invention comprises 0.1 to 1.2 wt% of an organic nucleating agent, 0.3 to 1.9 wt% of a light diffusing agent, 0.5 to 20 wt% of an anti- 0.1 to 2.8% by weight of other additives, and the remaining crystalline resin having a crystallinity of 45 to 70% based on an ordinary temperature of 25 占 폚.

The organic nucleating agent may be any one selected from the group consisting of sorbitol, ester, metal phosphate, and phosphates.

In addition, the modified agent is silicon dioxide (SiO _2), aluminum oxide (Al ₂ O _3), calcium (CaO), potassium oxide (K ₂ CO _3), barium sulfate (BaSo _4), trioxide, hydrogen (H ₂ O ₃ ), Sodium oxide (Na ₂ O), boron trioxide (B ₂ O ₃ ), magnesium oxide (MgO), zirconium oxide (ZrO ₂ ), monoamine oxidase (MaO), potassium oxide (K ₂ O) (TiO ₂ ), iron oxide (Fe ₂ O ₃ ), and ether (R ₂ O).

It is more preferable that the anti-deformation agent has a diameter or a width of 3 to 150 탆, a length of 9 to 700 탆, a rod having a length larger than the diameter or the width, and a plurality of kinds of anti- .

According to the present invention, the crystal of the crystalline resin diffuses the incident light primarily, and the light diffusing agent and the anti-strain agent diffuse the light secondarily, thereby realizing excellent luminance performance.

Also, since the shrinkage resistance is greatly increased due to the high crystallinity and the anti-sagging agent, when the crystalline resin having a high shrinkage ratio is produced by compression molding, warpage due to shrinkage is prevented and a light diffusion plate having high flatness can be manufactured.

1 is a cross-sectional view of a light diffuser according to an embodiment of the present invention.
Fig. 2 is a view showing various forms of the strain inhibitor used in the light diffusing plate composition of the present invention.
3 is a view showing a configuration of a compression molding machine for producing a light diffusion plate of the present invention.

Preferred embodiments of the crystalline resin light-diffusing plate composition according to the present invention will now be described in detail with reference to the accompanying drawings.

The optical diffuser plate 1 of the present invention comprises 0.1 to 1.2% by weight of an organic nucleating agent, 0.3 to 3% by weight of a light diffusing agent 2, (3) 0.5 to 20% by weight of other additives, 0.1 to 2.8% by weight of an antireflection agent containing inorganic particles and 45 to 70% of a crystallinity of 45 to 70% .

Polypropylene, acetal resin, polyamide, polyethylene and the like can be used as the crystalline resin constituting the light diffusing plate composition of the present invention. Hereinafter, polypropylene (PP) is applied as the crystalline resin.

The crystalline resin is referred to as the crystallinity (%) in which the crystalline portion and the amorphous portion coexist, in which crystals are formed, and the ratio of crystallization at that time is measured. For example, in the case of a polypropylene resin, crystallinity and amorphousness can be classified as follows.

(1) Crystal (Cristal) - a state in which it is combined in one direction only

(2) Amorphous - Irregularly bonded states without directionality

The polypropylene resin as the crystalline resin has a crystallinity of 45 to 70% based on an ordinary temperature of 25 占 폚. Polypropylene resin has higher density and higher rigidity and heat resistance as the degree of crystallinity increases. However, when the crystallinity exceeds 70%, the synergistic effect of stiffness and heat resistance is insignificant, but the manufacturing cost is excessively increased. The density becomes too low to cause deformation in a short time in a high temperature and high humidity state. The crystallinity can be measured using Differential Scanning Calorimetry, One Dimensin X-ray Diffraction (XRD) or density measurement.

The organic nucleating agent is added in an amount of 0.1 to 1.2% by weight based on the total weight of the organic nucleating agent to increase the degree of crystallization of the polypropylene. The organic nucleating agent may be an ester metal salt such as sorbitol, phosphoric acid or 2,2-methylbis (4,6-di-t-butylphenyl) sodium such as dibenzylidene sorbitol or its derivative, One or two or more of phosphates may be used.

The light-diffusing agent further enhances the light diffusion effect of the polypropylene resin crystal. Polystyrene (PS), polycarbonate (PC) and the like, which are conventional optical diffusion plate materials, are a primary method of functioning as light diffusion by a light diffusing agent, and there is a physical limit to realize high brightness. However, The light diffusing plate (1) of the present invention primarily reflects light incident on the polypropylene crystal, and the light diffusing agent (2) diffuses the light secondarily to realize excellent luminance performance. As the light diffusing agent, organic particles such as silicon and acrylic, or inorganic particles such as calcium carbonate can be used.

The transformation agent (3) is silicon dioxide (SiO _2), aluminum oxide (Al ₂ O _3), calcium oxide (CaO), potassium carbonate (K ₂ CO _3), barium sulfate (BaSo _4), trioxide, hydrogen (H ₂ O _3), sodium (Na ₂ O), trioxide, a boron (B ₂ O _3), magnesium (MgO), zirconium (ZrO _2), monoamine oxidase (MaO), potassium oxide (K ₂ O oxide oxidation), At least one inorganic particle selected from the group consisting of titanium dioxide (TiO ₂ ), iron oxide (Fe ₂ O ₃ ), and ether (R ₂ O), and having a diameter or width (a) of 3 to 150 μm , The length (b) is in the range of 9 to 700 mu m, and the shape of the round bar or the polygonal bar is larger than the diameter or the width. The anti-deformation agent (3) is arranged irregularly inside the optical diffusion plate to diffuse light incident to the inside of the optical diffusing plate to improve optical characteristics, and to increase the resistance and strength against shrinkage, Thereby preventing warpage deformation and providing a high flatness. It is preferable that the anti-sagging agent is added in an amount of 0.5 to 20% by weight based on the total weight of the optical diffusion plate. It is preferable that the same type of rod is used singly, desirable.

If the size of the anti-strain agent is out of the above numerical range, if it is too large, the light is blocked to lower the optical characteristics, while if it is too small, the anti-deformation agent can not exhibit the resistance to shrinkage. In addition, when a regular shape other than a long rod shape, for example, a cubic shape or a spherical shape, acts to improve compressive strength and surface hardness rather than causing resistance to shrinkage.

Other additives added to the light diffusion plate of the present invention may include stabilizers (antioxidants, light stabilizers, heat stabilizers), fluorescent brighteners, antistatic agents, and the like.

The stabilizer is classified into an antioxidant, a heat stabilizer, and a light stabilizer, and is used for inhibiting chemical decomposition during manufacturing and use of plastics. Examples of the antioxidant include a primary antioxidant and a secondary antioxidant. Examples of the primary antioxidant include a phenol-based or aromatic amine-based antioxidant. The secondary antioxidant plays a role of a primary antioxidant. And a phosphite compound and a sulfur compound. The addition amount is preferably 0.1 to 0.8% by weight based on the total weight, more preferably 0.3% by weight.

Examples of the light stabilizer include benzotriazole, benzophenone, cyanoacrylate, organometallic and the like. The amount added is preferably 0.1 to 1.0% by weight, more preferably 0.4% by weight based on the total weight, Or a combination of two or more.

Examples of the thermal stabilizer include a phenol-based, acrylate-based, and the like. In addition, a fluorescent whitening agent and an antistatic agent can be used.

A method for producing a light diffusion plate using the light diffusion plate composition having such a composition includes a material mixing step and an extrusion molding step.

The method of mixing the materials in the material mixing step includes a compound system in which the constituent components are collectively mixed and a master system in which the additive is concentrated and mixed in a part of the raw material with respect to the target amount to be produced ) Method.

The mixed material in the material mixing step is introduced into the main body 11 of the extrusion molding machine 10 through the hopper 12 of the extrusion molding machine 10 as shown in Fig. 3 and melted. Is extruded through the extrusion die 14, and then is made into a flat plate shape while passing through a plurality of forming rollers 15 made of three or more.

The light diffusion plate of the present invention made by such an extrusion molding method is mainly used for LED display, LED lighting, LED signing, etc., and is manufactured to have a thickness of 0.8 mm to 5 mm according to size and area. At this time, it is preferable that the amount of bending deformation of the optical diffusion plate 1 is within ± 3 mm (see FIG. 1).

Example 1

Table 1 below shows that the degree of crystallization of the crystalline resin (polypropylene) is changed according to the addition amount (weight ratio) of the organic nucleating agent. The crystalline resin used was 680S polypropylene resin (degree of crystallinity: 44.8%) manufactured by S synthesis, and the organic nucleating agent added was dibenzylidene sorbitol.

division Amount of organic nucleating agent added (% by weight) 0.1 0.3 1.0 1.2 1.5 Polypropylene
Crystallinity
(%, Room temperature 25 캜) Before organic nucleating agent addition 44.8 After adding the organic nucleating agent 49 64 69 72 73

As a result of the test, it was confirmed that the degree of crystallization was drastically increased from 0.1 wt% to 1.2 wt%, and the increase in crystallinity from 1.2 wt% or more was insignificant.

Example 2

As a result of the reliability test according to the degree of crystallization of the crystalline resin, the results shown in Table 2 below were obtained. The products A, B and C were each extruded to a thickness of 1.5 mm using a polypropylene resin (trade name: 930F, 680S, S120) manufactured by S < The extruded optical diffusing plate specimens were placed in a high - temperature (60 ° C) high humidity (90%) reliability test chamber and the degree of deformation was measured at each time. The crystallinity was measured by X-ray diffraction method and the measuring instrument was measured by Bruker's AXS XRD Series.

division Crystallinity (%)
Standard temperature 25 ℃ Temperature
(° C) Humidity
(%) 24 hours 48 hours 72 hours A 65.1
60
90 ◎ ◎ ◎ B 44.8 ◎ ○ △ C 51.6 ◎ ○ ○ D PS ◎ ○ ○

In Table 2, ⊚ indicates no deformation, ◯ indicates warp ± 3 mm or less, and Δ indicates warp ± 3 mm or more. As can be seen from Table 2, the higher the degree of crystallinity, the greater the resistance to shrinkage, so that the flexural deformation does not occur.

Example 3

In order to confirm the shrinkage resistance of the antireflection agent, a flatness test was carried out after preparing a light diffusion plate by adding a deformation preventing agent. 0.3 wt% of dibenzylidene sorbitol as an organic nucleating agent was mixed with a polypropylene resin having a crystallinity of 51.6 and 0.1 wt%, 0.5 wt%, 10 wt%, and 20 wt% of aluminum oxide (Al ₂ O ₃ ) %, And 25% by weight, and the resulting product was placed on a horizontal plane. The flatness of the product was measured and the results shown in Table 3 were obtained.

Strain inhibitor
Content (% by weight) 0.1 0.5 10 20 25 Deflection 3.8mm 2.4 mm 1.3 mm 1.2 mm 1.1mm

As shown in Table 3, when 0.1% by weight of the antireflection agent is added, the amount of flexural deformation of the optical diffusing plate is larger than 3 mm, which is the standard value, so that it can not be applied as a light diffusing plate, And the flatness was improved. However, when the amount of the anti-strain agent is 20 wt% or more, the production cost of the product is excessively increased and the anti-deformation agent is preferably 20 wt% or less in comparison with the flatness improving effect.

The light diffusing plate (PP light diffusing plate) manufactured by the optical diffusing plate composition according to the present invention was compared with the PC light diffusing plate made of the conventional PS resin diffuser plate made of polystyrene resin and the polycarbonate resin. The light diffusing plate of the present invention was prepared by mixing 0.4 wt% of dibenzylidene sorbitol as an organic nucleating agent into a polypropylene resin having a crystallinity of 51.6, mixing 1.2 wt% of polymethyl methacrylate powder as a light diffusing agent, ₂ O ₃ ) powder were mixed and extruded by an extruder to prepare a sample of a light diffusion plate having a thickness of 1.5 mm.

division PP light diffuser plate PC light diffuser plate PS light diffuser plate Thickness (mm) 1.5 Brightness (cd / m 2) 6396. (106.1%) 6209 (102.2%) 6029 (100%) Total light transmittance (%) 69.3 69.7 69.4

As a result of the test, it was confirmed that the brightness of the PP light diffusing plate of the present invention was the most superior to the similar light transmittance.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention as defined by the appended claims. And it is to be understood that such modified embodiments belong to the scope of protection of the present invention defined by the appended claims.

1: light diffuser plate 2: light diffuser
3: Deformation preventing agent 10: Extrusion molding machine
11: Main body 12: Hopper
13: screw 14: extrusion die
15: forming roller

Claims (1)

0.1 to 1.2% by weight of an organic nucleating agent selected from the group consisting of Sorbitol, Ester metal salts and Phosphates, 0.3 to 1.9% by weight of a light diffusing agent, resistance to shrinkage during extrusion molding 0.5 to 20% by weight of an anti-sagging agent composed of inorganic particles in the form of a round bar or a polygonal bar, 0.1 to 2.8% by weight of other additives, and a degree of crystallinity Of the polypropylene resin is 45 to 70%
The modification agent is silicon dioxide (SiO _2), aluminum oxide (Al ₂ O _3), calcium (CaO), potassium carbonate (K ₂ CO _3), barium sulfate (BaSo _4), sodium (Na ₂ O) oxide, trioxide, boron (B ₂ O _3), magnesium oxide (MgO), zirconium oxide (ZrO _2), potassium oxide (K ₂ O), titanium dioxide (TiO _2), iron oxide, one selected from the group consisting of (Fe ₂ O ₃₎ Wherein the inorganic particles are in the form of a circular rod or a polygonal rod having a diameter or a ratio of a width (a) to a length (b) of 1: 3 or more.

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