KR20070043347A - Polycarbonate resin composition having good spray resistance and impact strength - Google Patents

Abstract

The present invention relates to a polycarbonate (PC) -based resin composition having excellent scratch resistance and impact resistance, comprising: (A) 75 to 95 parts by weight of a polycarbonate resin, and (B) an acrylic modified fluorinated polyolefin resin. 0.15 to 0.5 parts by weight, (C) 5 to 15 parts by weight of titanium dioxide including the content of the inorganic coating layer 2% by weight or less, and (D) 3 to 10 parts by weight of a phosphate ester flame retardant.

Polycarbonate, acrylic modified fluorinated polyolefin resin, display resistance, impact resistance

Description

Polycarbonate resin composition having good spray resistance and impact strength

Polycarbonate resins are generally widely used as exterior and interior parts in the electric / electronic field because of their excellent impact resistance, heat resistance, self-extinguishing and transparency compared to other resins.

The polycarbonate resin composition of the present invention is required for physical properties such as high whiteness, high gloss, impact resistance and flame retardancy for an LCD backlight unit. Generally, a large amount of titanium dioxide (5% or more) has been used for high whiteness and high gloss. However, titanium dioxide decomposes polycarbonate resins, which may cause deterioration in impact and splay (stripes, silverstreak) on the surface of the product, and may adversely affect the light efficiency of the LCD due to deterioration of gloss.

As a conventional technology for compounding products for LCD backlight units, in order to minimize the splay phenomenon, Akio Nodera et al. A non-halogen phosphate compound and other conventional additives are blended to give excellent light-blocking properties, flame retardancy, and low delta E, resulting in reduced silver streaks with high thermal stability during injection. To obtain. More specifically, in the patent, a primary effect was obtained by mixing titanium dioxide powder and non-halogen phosphate in order to minimize the splay phenomenon, and polyorganosiloxane having an alkoxy group. Was added to obtain the effect of minimizing flame retardancy and splay. However, the synergy between titanium dioxide powder and non-halogen phosphate is commonly known knowledge, and the addition of polyorganosiloxane with alkoxy groups to the compound is a method of extrusion. As a result, splats are more likely to occur and may cause a drop in impact when overdosed.

As another conventional technique for minimizing splay, James et al. Described in US Pat. No. 6,180,702 that polycarbonates, acrylic modified fluorinated olefin resins, and metal salt-based flame retardants can be used to achieve improved flame retardancy and suppress splay. have. The acrylic modified fluorinated olefin resin used in the patent has a composition of 5 to 30%, more preferably 10 to 20% of the fluorinated olefin resin. In addition, 0.5% or more of the acrylic modified fluorinated olefin resin is added to the total composition. However, when the fluorinated olefin resin in the acrylic modified fluorinated olefin resin is 30% or less, flame retardancy (prevention of dropping), which is a basic requirement, may be reduced. In addition, when the content to be added to the total composition is 0.5% or more in the polycarbonate composition for LCD backlight unit using a large amount (5% or more) of titanium dioxide can be a result of the splay occurs severely.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide excellent surface properties without splay, including an acrylic modified fluorinated polyolefin resin and a titanium dioxide and a phosphate ester flame retardant containing 2 wt% or less of an inorganic coating layer. It is to provide a polycarbonate resin composition for an LCD backlight unit with improved impact resistance.

The composition according to the present invention is 30 to 70% by weight of the acrylic modified fluorinated olefin resin in the composition of the acrylic modified fluorinated olefin resin in order to obtain the high whiteness, high gloss and impact resistance properties required for the LCD backlight unit. The content of the resin was 0.5 parts by weight or less based on the total composition to minimize the splay phenomenon.

The present invention includes (A) 75 to 95 parts by weight of polycarbonate resin, (B) 0.15 to 0.5 parts by weight of acryl-modified fluorinated polyolefin resin, and (C) 5 to 15 parts by weight of titanium dioxide including 2% by weight or less of the inorganic coating layer. Part, (D) Polycarbonate-based resin composition for an LCD backlight unit comprising 3 to 10 parts by weight of a phosphate ester flame retardant, a detailed description thereof is as follows.

The polycarbonate resin (A) used in the present invention is a commonly used aromatic polycarbonate resin which reacts with dihydric phenol and phosgene or by using ester interchange reaction of dihydric phenol with a carbonate precursor (precursor). Linear and branched polycarbonate homopolymers and polyester copolymers prepared and the like. The dihydric phenol is 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxy-3,5-di Methylphenyl) propane, or 1,1-bis (4-hydroxyphenyl) cyclonucleic acid, and the like, and the carbonate precursors include, but are not limited to, diphenyl carbonate, carbonyl halide, diaryl carbonate, and the like.

The polycarbonate according to the present invention uses a viscosity average molecular weight (Mv) of 17,000 ~ 25,000, if the molecular weight is less than 17,000 impact strength and tensile strength is lowered, if the molecular weight exceeds 25,000 of the resin by the rise of the melt viscosity During processing, splay occurs due to hot forming conditions.

In addition, (A) polycarbonate resin according to the present invention is used in 75 to 95 parts by weight, preferably 80 to 90 parts by weight. When the polycarbonate resin is less than 75 parts by weight, the content of titanium dioxide and the flame retardant may be increased compared to the content of the polycarbonate resin, thereby reducing the impact resistance and splattering. When the content is more than 95 parts by weight, the titanium dioxide is more than the polycarbonate resin content. And the content of flame retardant is reduced and the light blocking property and flame retardancy is lost.

The acrylic modified fluorinated polyolefin resin (B) used in the present invention is generally a fluorinated polyolefin resin, that is, a copolymer of polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene, or vinylidene fluoride, and It has a different structure from the copolymer of tetrafluoroethylene and hexafluoropropylene. Normally, fluorinated polyolefin resins have very low surface energy, so they may be used for lubrication, low friction, or wear resistance. However, when the fluorinated polyolefin resin is used as a flame retardant aid (anti-dropping agent) in the high white / high gloss flame retardant polycarbonate-based composition which can be used in the LCD backlight unit, its compatibility with the polycarbonate matrix is lowered due to its inert surface state. As a result, a large amount of fluorinated polyolefin resin migrates to the surface during high-speed injection, causing a splash.

In order to solve such a problem, the present invention uses an acrylic modified fluorinated polyolefin resin including 30 to 70 wt% of acrylic resin having excellent compatibility with polycarbonate and 70 to 30 wt% of fluorinated polyolefin resin having flame retardancy. When the acrylic resin is less than 30% by weight, the effect of improving the compatibility with polycarbonate is inadequate. When the acrylic resin is more than 70% by weight, the content of the emulsion-type fluorinated olefin resin of the core component is less than 30% by weight, thereby preventing dropping. There is no.

The acrylic resin that can be used in the present invention can be used without limitation as long as it has excellent compatibility with polycarbonate, but polyalkyl methacrylate is preferable. The polyalkyl methacrylate suitable for the present invention is at least one selected from the group consisting of polymethyl methacrylate, polybutyl methacrylate, polydecyl methacrylate, polydodecyl methacrylate and polytridecyl methacrylate. Can be used.

In addition, in order to prevent a fluorinated polyolefin resin from moving to the surface, it is preferable to use what superposed | polymerized the acrylic resin as a shell component and the emulsion type fluorinated polyolefin resin as a core component. Thus, when using an acrylic resin as a shell component, the effect of improving dispersibility and reducing the surface migration characteristic of a fluorinated polyolefin resin can be acquired.

In addition, another method of preventing the transition of the fluorinated olefin resin to the surface is to use a high molecular weight fluorinated polyolefin having a high molecular weight and a very narrow molecular weight distribution, that is, a low content of the low molecular weight content can be further improved. have.

On the other hand, the acrylic modified fluorinated polyolefin resin according to the present invention is preferably used emulsion type fluorinated polyolefin resin having a number average molecular weight of 5,000,000 or more, more preferably 5,000,000 to 10,000,000. When the molecular weight of the fluorinated olefin resin is less than 5,000,000, it is difficult to express characteristics as an anti-dripping agent, and the fluorinated olefin resin may migrate to the surface and deteriorate the display characteristics.

In the present invention, the acrylic modified fluorinated polyolefin resin is used in an amount of 0.15 to 0.5 parts by weight, preferably 0.25 to 0.35 parts by weight. If the acrylic modified fluorinated polyolefin resin is less than 0.15 parts by weight, the flame retardancy may be lowered. If the acrylic modified fluorinated polyolefin resin is more than 0.5 parts by weight, the splay is intensified and fluidity and impact resistance are deteriorated.

As described above, the acrylic modified fluorinated polyolefin resin according to the present invention has excellent compatibility with polycarbonates compared to the fluorinated polyolefin resins which are generally used, and thus improves dispersibility in a polycarbonate matrix, thereby improving impact resistance. In addition, the excellent compatibility with polycarbonate can result in a significant reduction in the splay characteristics due to the transition to the surface during high-speed injection. In addition, due to the excellent compatibility with polycarbonate, the dispersibility is improved, the fluidity is also superior to the case of using a conventional fluorinated polyolefin resin.

(C) titanium dioxide which can be used in the present invention uses a rutile type produced by hydrochloric acid method from ore. The polycarbonate-based composition for the LCD backlight unit should have high light blocking property, and generally shows a high light blocking property as the refractive index of the white polymer and the matrix polymer has a large difference. Of these materials, rutile titanium dioxide has the highest refractive index of 2.73. For reference, the refractive indices of anatase type titanium dioxide and polycarbonate are 2.55 and 1.59, respectively. The anatase type is more sensitive to light than rutile type, and has a greater degree of decomposing the polycarbonate matrix, causing a drop in impact strength.

Generally, rutile type titanium dioxide has an inorganic coating or an organic coating or both coatings in its core. The inorganic coating layer is for wetting and UV blocking effect, and may use alumina, silica, zirconia, or the like depending on its use. In addition, the organic coating layer is to improve the dispersibility and thermal stability, the composition is composed of one coating layer or two coating layers depending on the use, the organic material that can be used may be an organic silane and an organic siloxane compound.

Titanium dioxide used in the present invention is that the content of the inorganic coating layer is 2% by weight or less. That is, even if there is no inorganic coating layer or has a coating layer treated at 2% by weight or less. When the content of the inorganic coating layer is more than 2% by weight, it is easy to absorb moisture, causing severe splay during the production of the product, and causing the degradation of polycarbonate, which may be a reason for deteriorating physical properties. Titanium dioxide used in the present invention preferably has two organic coating layers, which serve to improve dispersibility and thermal stability. In the case of one organic coating layer, dispersibility and thermal stability may be lowered, such that physical properties and color change may occur.

(C) titanium dioxide according to the present invention is used in 5 to 15 parts by weight, preferably 8 to 12 parts by weight. When the titanium dioxide is less than 5 parts by weight, the light blocking effect may be lowered. When the titanium dioxide is more than 15 parts by weight, impact, fluidity, and splay phenomenon are severely generated.

The flame retardant (D) which can be used in the present invention is a non-halogen flame retardant. Typical non-halogen flame retardants for polycarbonates include phosphate esters, metal salts, and silicones. However, metal salts have excellent flame retardancy but tend to decompose polycarbonate at high temperature, and silicones have difficulty in obtaining V-0 grade of UL94 when used alone. In addition, excessive gloss decreases the surface gloss and intensifies the splay phenomenon.

Therefore, in the present invention, a phosphate ester flame retardant is used, and examples of the phosphate ester flame retardant which can be used in the present invention include triphenyl phosphate, resorcinol diphosphate, bisphenol A oligomeric phosphate ester, resorcinol digyrenyl phosphate, and tri (2). At least one selected from the group consisting of 6-dimethylphenyl) phosphate, tri (4-methylphenyl) phosphate, tricresylphosphate, diphenylcresylphosphate, triisopropylphenylphosphate, trigylenylphosphate, and xylenyldiphenylphosphate Can be used.

(D) Phosphate ester flame retardant according to the present invention is used in 3 to 10 parts by weight, preferably 5 to 7 parts by weight. If the phosphate ester flame retardant is less than 3 parts by weight, flame retardancy may be lowered. If it exceeds 10 parts by weight, the use range is reduced by lowering heat resistance.

The composition of the present invention may further include a conventionally added ultraviolet absorber, heat stabilizer, antioxidant, and / or lubricant and the specific types and amounts of use are within the range that can be appropriately selected by those skilled in the art as needed. .

Example

Specifications of each component used in the following Examples and Comparative Examples are as follows.

(1) PC-1: Bisphenol-A linear polycarbonate having a viscosity average molecular weight of about 21,000

(2) PC-2: Bisphenol-A linear polycarbonate having a viscosity average molecular weight of about 15,000

(3) PC-3: Bisphenol-A linear polycarbonate having a viscosity average molecular weight of about 30,000

(4) PTFE-1: Acrylic modified fluorinated polyolefin resin, which is composed of 50 parts by weight of pure PTFE in the core and 50 parts by weight of polymethylmethacrylate resin in the shell with respect to 100 parts by weight of PTFE-1. Polymers from 5,000,000 to 10,000,000

(5) PTFE-2: Teflon 800J, emulsion type of Dupont, USA, has an apparent bulk density of 850 g / l

(6) PTFE-3: Teflon 7AJ, emulsion type of Dupont, USA, with an apparent bulk density of 450 g / l

(7) TiO2-1: Titanium dioxide in which the first organic coating is silane and the second organic coating is organosiloxane in rutile type titanium dioxide without inorganic surface treatment. Particle size is 0.15 to 0.25 μm.

(8) TiO2-2: Titanium dioxide in which a rutile-type titanium dioxide is surface treated with alumina and silica, the first organic coating is a linear siloxane, and the second organic coating is an organosiloxane. Particle size is 0.20 to 0.30 μm.

(9) FR: Lesosinol Designenyl Phosphate, a Phosphate Ester Flame Retardant

(10) Others: 1 to 3 parts by weight of a UV absorber, a heat stabilizer, an antioxidant, a lubricant and the like based on 100 parts by weight of the total composition.

The pellets were prepared by mixing the components in a Super mixer for about 2 minutes and placing them in an extruder hopper. The extruder used a 12 barrel 30mm extruder manufactured by Japan Steel Works. RPM was set to 200 and the melting temperature was set for each part based on 280 ° C. The pellets thus prepared were manufactured into splay specimens, impact specimens, and flame retardant specimens using an injection machine. The splay specimens were injected at 300 ° C. in the form of flakes of 80 mm × 80 mm × 10 mm. Impact specimens and flame retardant specimens were manufactured by injection molding at 280 ° C in accordance with ASTM and UL94 standards.

The composition of each component used in Examples 1 to 5 and Comparative Examples 1 to 7 is as shown in Table 1 and Table 2, the unit used in the composition is parts by weight.

Example Furtherance One 2 3 4 5 PC-1 84.85 84.7 79.7 89.7 84.5 PC-2 - - - - - PC-3 - - - - - PTFE-1 0.15 0.3 0.3 0.3 0.5 PTFE-2 - - - - - PTFE-3 - - - - - TiO2-1 10 10 15 5 10 TiO2-2 - - - - - FR 5 5 5 5 5 Etc 2 2 2 2 2

Comparative example Furtherance One 2 3 4 5 6 7 PC-1 84.7 84.7 84.7 - - 84 84.7 PC-2 - - - 84.7 - - - PC-3 - - - - 84.7 - - PTFE-1 - - 0.3 0.3 0.3 1.0 0.3 PTFE-2 0.3 - - - - - - PTFE-3 - 0.3 - - - - - TiO2-1 10 10 - 10 10 10 10 TiO2-2 - - 10 - - - - FR 5 5 5 5 5 5 - Etc 2 2 2 2 2 2 2

Splay, impact strength, melt index, and flame retardancy were evaluated for the specimens prepared according to Examples 1 to 5 and Comparative Examples 1 to 7.

The evaluation of the splay was based on visual inspection, and five people were evaluated by grade 1 stage (less splay) to stage 5 (many splay) for 10 sample flakes for each sample. The final evaluation index was taken as the average of the total sum. The splay grade indicates that the lower the value, the less the splay phenomenon.

Impact strength and melt index were measured according to ASTM D256 and D1238 methods, respectively, and flame retardancy was measured according to UL94 method using 3.0mm thick specimens.

Splay 1/8 "Notched Izod Impact Strength (kgcm / cm) MFI (300 ℃, 1.2kgf) Flame Retardant (UL94) Example One 1.2 70 22 V-O 2 1.3 69 21 3 1.8 62 17 4 1.1 74 25 5 1.5 67 19 Comparative example One 3.9 60 12 2 3.8 61 14 3 3.5 66 20 4 1.2 28 45 5 2.7 76 9 6 2.9 59 17 7 2.4 72 15 V-2

Looking at Comparative Examples 1 and 2 that do not contain the component (B) according to the present invention, the splay (Splay) was noticeably worse and the fluidity tended to decrease. In Comparative Example 3, the use of another type of titanium dioxide containing 2 wt% or more of the inorganic coating layer caused severe splay. In the molecular weight tests of Comparative Examples 4 to 5, both the flow and the splay are good in the case of low molecular weight, but the impact strength is low, and in the case of the high molecular weight, the rapid decrease in fluidity and the deterioration of the splay phenomenon occur. If the fluidity is lowered, the splay may be more severe than that of the specimen due to the complicated structure of the thin film in the actual product injection. In Comparative Example 6, when the component (B) is added in an excessive amount, the splay may be intensified, and the fluidity and the impact property may be reduced. In Comparative Example 7, the absence of the (D) component may cause a sharp decrease in flame retardancy and may cause severe splay due to the disappearance of the flow improving effect inherent in the phosphate ester flame retardant.

A composition in which a conventional fluorinated polyolefin resin and a rutile type titanium dioxide having a large inorganic coating amount and polycarbonate are mixed with a splay is severe, and impact resistance and fluidity are reduced. However, a composition in which the acrylic modified fluorinated polyolefin resin having a specific composition used in the present invention and titanium dioxide including an inorganic coating layer of 2% by weight or less and a phosphate ester flame retardant is mixed with a polycarbonate resin has an excellent improvement in splay phenomenon and impact resistance. Improvements and increased fluidity allow for superior quality for LCD backlight units.

Claims (10)

(A) 75 to 95 parts by weight of polycarbonate having a viscosity average molecular weight of 17,000 to 25,000; (B) 0.15 to 0.5 parts by weight of acrylic modified fluorinated polyolefin resin including 30 to 70% by weight of acrylic resin and 70 to 30% by weight of fluorinated polyolefin resin; (C) 5 to 15 parts by weight of titanium dioxide including 2% by weight or less of an inorganic coating layer; And (D) Polycarbonate resin composition comprising 3 to 10 parts by weight of a phosphate ester flame retardant. The polycarbonate resin composition according to claim 1, wherein the acrylic modified fluorinated polyolefin resin is polymerized with an acrylic resin as a shell component and a fluorinated polyolefin resin as a core component. The method of claim 1 or 2, wherein the acrylic resin, the polyalkyl methacrylate is polymethyl methacrylate, polybutyl methacrylate, polydecyl methacrylate, polydodecyl methacrylate and polytridecyl methacrylate Polycarbonate methacrylate, characterized in that at least one selected from the group consisting of a rate. The polycarbonate resin composition according to claim 1 or 2, wherein the acrylic modified fluorinated polyolefin resin comprises 45 to 55 wt% of acrylic resin and 55 to 45 wt% of fluorinated polyolefin resin. The polycarbonate resin composition according to claim 1 or 2, wherein an acrylic modified fluorinated polyolefin resin is used at 0.25 to 0.35 parts by weight. The polycarbonate resin composition according to claim 1 or 2, wherein the number average molecular weight of the fluorinated polyolefin resin is 5,000,000 or more. The polycarbonate resin composition of claim 1, wherein the titanium dioxide comprises at least one organic coating layer selected from the group consisting of an organosilane and an organosiloxane compound. The phosphate ester flame retardant according to claim 1, wherein the phosphate ester flame retardant is triphenyl phosphate, resorcinol diphosphate, bisphenol A oligomeric phosphate ester, resorcinol dinyrenyl phosphate, tri (2,6-dimethylphenyl) phosphate, tri (4- A polycarbonate resin composition comprising at least one selected from the group consisting of methylphenyl) phosphate, tricresylphosphate, diphenylcresylphosphate, triisopropylphenylphosphate, trigylenylphosphate, and xylenyldiphenylphosphate. The polycarbonate resin composition of claim 1, further comprising at least one additive selected from the group consisting of ultraviolet absorbers, heat stabilizers, antioxidants, and lubricants. 10. An LCD backlight unit comprising the polycarbonate resin composition according to any one of claims 1, 2, 7, 8, or 9.