JP2012132947A - Front plate for liquid crystal television - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front plate for a liquid crystal television, which is obtained by molding a resin composition containing a branched polycarbonate resin as an essential component and is characterized in that the resin composition comprises 100 pts.wt. of a resin component comprising 40 to 100% by weight of a branched polycarbonate resin (A) and 0 to 60% by weight of a linear polycarbonate resin (B), 0.005 to 0.5 pts.wt. of a specific silicon compound (C), and 0.005 to 0.2 pts.wt. of an organic metal salt (D), and a haze measured on the basis of (2)JIS K7361 by using a test piece obtained by molding the resin composition and having a thickness of 3.0 mm is 2% or less.SOLUTION: The front plate for a liquid crystal television has high fire retardancy while maintaining transparency, and can create higher quality mood when being mounted on the periphery of a screen of a liquid crystal television. Since flame retardants such as chlorine and bromine and phosphorous flame retardants are not employed, the front plate has environmentally excellent features.

Description

  The present invention relates to a front panel for a liquid crystal television. More specifically, the present invention provides a front panel for a liquid crystal television that is excellent in transparency and design, and does not use a chlorine or bromine-based flame retardant and imparts flame retardancy.

There is a remarkable spread of large-screen LCD TVs. Conventionally, flame retardant resins such as styrene resins and polycarbonate / ABS alloys have been used as housings used in this liquid crystal television.
On the other hand, with the increase in the size of liquid crystal televisions, a technique for enhancing customer satisfaction and purchasing motivation by attaching a front plate such as a glass plate to the front of a television screen to produce a high-class feeling has been taken. However, there is a problem that the glass plate has a risk of being broken and a heavy weight, and an alternative to resin has been desired.

  As a resin alternative candidate, a polycarbonate resin excellent in transparency, impact resistance, heat resistance, thermal stability and the like has attracted attention. Polycarbonate resin is a highly flame-retardant resin material with self-extinguishing properties, but in the application of television, it is in UL94 test (flammability test of plastic materials for equipment parts) defined by Underwriters Laboratories. In the evaluation of flame retardance in accordance with the standard, it is strongly desired to be V-0 grade.

  As a technique for imparting flame retardancy to a polycarbonate resin, conventionally, a method of blending chlorine, a bromine compound, or a phosphorus compound as a flame retardant has been adopted. However, chlorine and bromine-based flame retardants exhibit excellent flame retardant effects, but have problems such as corrosion of molding machine screws and product molds during injection molding. Moreover, although the phosphorus-based flame retardant is mainly used as a condensed phosphate ester-based flame retardant, there is a problem that an extreme decrease in heat resistance or impact strength occurs. In view of these remarkable physical properties and environmental considerations, it is desired to use a flame retardant that does not contain halogen compounds such as bromine and chlorine and phosphorus compounds.

  As a method of making flame retardant without using the above flame retardant, a method of adding an aromatic sulfonic acid metal salt to a polycarbonate resin (Patent Document 1), a method of adding potassium perfluoroalkane sulfonate (Patent Document 2), and branching A method of adding an organic alkali metal salt to a glassy polycarbonate resin (Patent Document 3) has been proposed. By using these methods, in the evaluation of flame retardancy based on the UL94 test, the effect of reducing combustion time and the effect of suppressing dripping of resin during combustion are recognized to some extent. There is a need for the development of materials that are not sufficient to satisfy, and that have even better flame retardancy.

  On the other hand, a resin composition (Patent Document 4) in which a polyorganosiloxane having a weight average molecular weight of 400 to 1500 and an organic sulfonic acid metal salt is blended with a branched polycarbonate resin is disclosed. However, when a siloxane having the molecular weight range is used, the heat resistance of the siloxane itself is lowered, the flame retardancy effect is lowered, and the melt viscosity is too low. In some cases, the moldability may be deteriorated, for example, by deteriorating the appearance of the surface of the molded body. Therefore, development of a material having not only flame retardancy but also excellent moldability has been desired.

  Furthermore, as a method for suppressing dripping during combustion, a resin composition (Patent Document 5) in which a fluorinated polyolefin is added to a polycarbonate resin is disclosed. In such a composition, although dripping during combustion is suppressed and flame retardancy is improved, the fluorinated polyolefin is oriented in the flow direction of the resin during injection molding, or the aggregate of the fluorinated polyolefin is formed on the surface of the product. There has been a problem in that the appearance value is deteriorated and the value as a product is remarkably lowered. Further, when fluorinated polyolefin is added to a polycarbonate resin, there is a problem that the excellent transparency inherent in the polycarbonate resin is impaired, and there is a fundamental problem particularly in applications where transparency is required.

JP 50-98546 A Japanese Patent Publication No. 47-40445 JP-A-7-258532 JP 2001-26704 A Japanese Patent Publication No. 60-38418

  The present invention improves the above-mentioned problems such as flame retardancy, deterioration of physical properties, poor appearance, moldability, etc. and is transparent without using halogen flame retardants such as bromine and chlorine, phosphorus flame retardants or fluorinated polyolefins. An object of the present invention is to provide a front panel for a liquid crystal television having high flame retardancy while maintaining the properties.

  As a result of intensive studies in view of such problems, the present inventor has formed a polycarbonate resin composition using a branched polycarbonate resin as an essential component as a polycarbonate resin and further blending a specific silicone compound and an organic metal salt. Thus, the present inventors have found that a liquid crystal television front plate that solves the above-described problems can be obtained, thereby completing the present invention.

That is, the present invention is a front panel for a liquid crystal television formed by molding a resin composition containing a branched polycarbonate resin as an essential component, wherein the resin composition is
(1) 100 parts by weight of a resin component consisting of 40 to 100% by weight of a branched polycarbonate resin (A) and 0 to 60% by weight of a linear polycarbonate resin (B), the main chain having a branched structure and containing an organic functional group 0.005 to 0.5 parts by weight of a silicone compound (C) consisting of an aromatic group or consisting of an aromatic group and a hydrocarbon group (excluding an aromatic group) and an organometallic salt (D) 0.005 The haze measured by using a test piece having a thickness of 3.0 mm obtained by molding the resin composition according to JIS K7361 is 2% or less. ,
The present invention provides a front panel for a liquid crystal television.

  The front panel for a liquid crystal television of the present invention has high flame retardancy while maintaining transparency, and can be further enhanced by attaching it to the periphery of the screen of the liquid crystal television. In addition, since it does not use a flame retardant such as chlorine or bromine and a phosphorus flame retardant, it has excellent features in terms of environment.

  The branched polycarbonate resin (A) used in the present invention is a phosgene method in which a dihydroxydiaryl compound, a branching agent and phosgene are reacted, or a dihydroxydiaryl compound, a branching agent and a carbonate such as diphenyl carbonate are reacted. A polymer obtained by a transesterification method, and representative examples thereof include a branched polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), a branching agent and phosgene. .

Examples of the dihydroxydiaryl compound include bisphenol 4-, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2, 2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3) -Tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis ( Bis (hydroxyaryl) alkanes such as 4-hydroxy-3,5-dichlorophenyl) propane, 1,1- (4-hydroxyphenyl) cyclopentane, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3 Dihydroxy diaryl ethers such as 3,3'-dimethyldiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, dihydroxy diaryl sulfides such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, 4,4 ' -Dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-
Examples include dihydroxydiaryl sulfoxides such as 3,3′-dimethyldiphenyl sulfoxide, dihydroxydiaryl sulfones such as 4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfone, and the like. It is done.

These may be used alone or in combination of two or more. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4′-dihydroxydiphenyl, and the like may be used in combination.

Examples of the trivalent or higher phenol used as a branching agent include phloroglucin, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -heptene-2, 4,6-dimethyl-2,4. , 6-tri- (4-hydroxyphenyl) -heptane, 1,3,5-tri- (4-hydroxyphenyl) -benzol, 1,1,1-tris- (4-hydroxyphenyl) -ethane and 2, 2-bis- [4,4- (4,4′-dihydroxydiphenyl) -cyclohexyl] -propane and the like.

  Although there is no restriction | limiting in particular in content of these branching agents, It is preferable that it is 0.01 to 5.0 weight% per branched polycarbonate resin from the surface of a moldability.

  Although there is no restriction | limiting in particular in the molecular weight of branched polycarbonate resin (A), Melt flow rate (MFR) (300 degreeC, 1.2Kg load) is 1.0-20.0 g / 10min from the surface of moldability. It is preferable that

  The branched polycarbonate resin (A) can be produced by a conventionally known method. For example, JP-A-56-55328, JP-A-58-23825, JP-A-59-45318, JP-A-59-133223, JP-A-59-134742, JP-A-62-10071, JP-A-62-15223. And the like.

  The linear polycarbonate resin (B) used in the present invention is a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted, or a transesterification method in which a dihydroxydiaryl compound and a carbonate such as diphenyl carbonate are reacted. A typical example is a linear polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (commonly referred to as bisphenol A).

  As said dihydroxy diaryl compound, the various compound used for the above-mentioned branched polycarbonate resin (A) can be used similarly.

  The viscosity average molecular weight of the linear polycarbonate resin (B) is not particularly limited, but is usually in the range of 10,000 to 100,000, more preferably 15,000 to 40,000, and still more preferably 17,000 to 28,000 in terms of moldability and strength. . Moreover, when manufacturing this polycarbonate resin, a molecular weight modifier, a catalyst, etc. can be used as needed. The blending ratio of the linear polycarbonate resin (B) is 0 to 60% by weight in blending with the branched polycarbonate resin (A). ((A) + (B) = 100% by weight) If the blending ratio of the linear polycarbonate resin (B) exceeds 60% by weight, the flame retardancy is lowered, which is not preferable.

The silicone compound (C) used in the present invention comprises a branched main chain and an organic functional group comprising an aromatic group, or an aromatic group and a hydrocarbon group (excluding an aromatic group). Is represented by the following general formula (1).
General formula (1)

Here, R1, R2, and R3 represent main chain organic functional groups, and X represents a terminal functional group.
That is, it has a T unit (RSiO _1.5 ) and / or a Q unit (SiO _2.0 ) as a branch unit. These preferably contains more than 20 mol% of the total siloxane units _{(R 3~0 SiO 2~0.5).} (R represents an organic functional group.) Further, the silicone compound (C) preferably contains 20 mol% or more of aromatic groups among the organic functional groups contained.

  The aromatic group contained is phenyl, biphenyl, naphthalene or a derivative thereof, but a phenyl group can be preferably used.

  Of the organic functional groups in the silicone compound (C) attached to the main chain or branched side chain, the organic group other than the aromatic group is preferably a hydrocarbon group having 4 or less carbon atoms, and preferably a methyl group. Can be used. Further, the terminal group is preferably one kind selected from methyl group, phenyl group and hydroxyl group, or a mixture of these two kinds to three kinds.

  The average molecular weight (weight average) of the silicone compound (C) is preferably 3,000 to 500,000, and more preferably 5,000 to 270000. If it is less than 3000, the heat resistance of the silicone itself is lowered and a sufficient flame retardant effect cannot be obtained. Further, the melt viscosity is too low, and the silicone compound may bleed out on the surface of the molded product, which may impair the appearance. On the other hand, if it exceeds 500,000, the melt viscosity increases and uniform dispersion in the polycarbonate resin cannot be achieved, and the flame retardancy and moldability are lowered, which is not preferable. More preferably, it is 10,000 to 270000. In this range, since the melt viscosity is optimum, better flame retardancy and formability can be achieved.

  The compounding quantity of a silicone compound (C) is 0.005-0 per 100 weight part of resin components which consist of a branched polycarbonate resin (A) 40-100 weight% and a linear polycarbonate resin (B) 0-60 weight%. .5 parts by weight. If the blending amount is less than 0.005 parts by weight, a sufficient flame retardant effect cannot be obtained, and if it exceeds 0.5 parts by weight, the transparency is poor, which is not preferable. More preferably, it is the range of 0.03-0.3 weight part.

  Examples of the organic metal salt (D) used in the present invention include aromatic sulfonic acid metal salts, perfluoroalkanesulfonic acid metal salts, and perfluoroalkanesulfonic acid imide metal salts. Examples of the metal include alkali metals and alkaline earth metals. Preferably, potassium salt of 4-methyl-N- (4-methylphenyl) sulfonyl-benzenesulfonamide, potassium diphenylsulfone-3-sulfonate, potassium diphenylsulfone-3-3'-disulfonate, paratoluenesulfonic acid Sodium, potassium perfluorobutane sulfonate, sodium perfluorobutane disulfonate, potassium perfluoropropane disulfonimide, potassium bis (nonafluorobutanesulfonyl) imide, etc. can be used. In particular, potassium perfluorobutanesulfonate can be suitably used.

  The compounding amount of the organometallic salt (D) is 0.005 to 100 parts by weight of a resin component consisting of 40 to 100% by weight of the branched polycarbonate resin (A) and 0 to 60% by weight of the linear polycarbonate resin (B). 0.2 parts by weight. If it is less than 0.005 parts by weight, the flame retardancy is lowered, which is not preferable. Moreover, since it is inferior to transparency in the compounding quantity exceeding 0.2 weight part, it is unpreferable. Preferably it is 0.02-0.15 weight part, More preferably, it is 0.04-0.10 weight part.

  In particular, the compounding amount of the silicone compound (C) is 0.03 to 0.3 parts by weight, and the compounding amount of the organometallic salt (D) is 0.04 to 0.10 parts by weight (each branched polycarbonate resin ( A) 40% to 100% by weight and linear polycarbonate resin (B) per 100 parts by weight of resin component consisting of 0 to 60% by weight), both transparency and flame retardancy are significantly improved. Therefore, it is particularly preferable to use both components (C) and (D) within this range.

  There are no particular restrictions on the blending method and melt kneading method of the various blending components (A), (B), (C), and (D) of the present invention, and any mixer such as a tumbler, ribbon blender, high-speed mixer, etc. These can be mixed and melt-kneaded with a normal single-screw or twin-screw extruder. Moreover, there is no restriction | limiting in particular also about the mixing | blending order of these compounding components, collective mixing, and division | segmentation mixing.

  In addition, other known additives such as mold release agents, fillers, antistatic agents, antioxidants, phosphorous heat stabilizers, ultraviolet absorbers, dyes and pigments, spreading agents (epoxies) may be used as necessary. Modified soybean oil, liquid paraffin, and the like).

  As a method for molding the front panel for a liquid crystal television of the present invention, a T-die extrusion molding method, a calendar molding method, or the like can be used. Moreover, you may provide functional layers, such as a hard coat and reflection prevention, on the surface of a front board as needed.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Parts and% are based on weight unless otherwise specified.

The details of the used blending components are as follows.
Branched polycarbonate resin: (hereinafter abbreviated as PC-1)
Caliber 600-3 (viscosity average molecular weight: 24000) manufactured by Dow Chemical
Linear polycarbonate resin: (hereinafter abbreviated as PC-2)
Caliber 200-3 (viscosity average molecular weight: 28000) manufactured by Sumitomo Dow

Silicone compound: (hereinafter abbreviated as silicone)
Silicone was produced according to a general production method. That is, a silicone compound partially condensed by dissolving an appropriate amount of diorganodichlorosilane, monoorganotrichlorosilane and tetrachlorosilane, or a partially hydrolyzed condensate thereof in an organic solvent, adding water and hydrolyzing it. Then, triorganochlorosilane was added and reacted to terminate the polymerization, and then the solvent was separated by distillation or the like. The structural properties of the silicone synthesized by the above method are as follows:
・ D / T / Q unit ratio of main chain structure: 40/60/0 (molar ratio)
-Ratio of phenyl group in all organic functional groups (*): 60 mol%
-Terminal group: methyl group only-Weight average molecular weight (**): 15000
*: The phenyl group is first contained in the T unit in the silicone containing the T unit, and the remaining D group is contained in the D unit. When the phenyl group is attached to the D unit, the one attached is preferential, and when the phenyl group remains, two are attached. Except for the terminal group, the organic functional group is a methyl group except for the phenyl group.
**: Weight average molecular weight is two significant digits.

Organometallic salt: (hereinafter abbreviated as metal salt)
Potassium perfluorobutanesulfonate

(Transparency evaluation)
The pellets of various resin compositions obtained based on the blending components and blending ratios shown in Tables 2 to 4 were dried at 125 ° C. for 4 hours, and then set using an injection molding machine (Japan Steel Works J-100SAII). A test piece for transparency evaluation (150 × 90 × 3.0 mm) was prepared at 320 ° C. Based on JIS K7361, the cloudiness (haze) of the 3.0 mm thickness part of the produced test piece was measured. The results are shown in Tables 2-4.

(Flame retardance evaluation)
After the pellets of the various resin compositions obtained were dried at 125 ° C. for 4 hours, a test piece for flame retardancy evaluation (125 × 13 × 1...) At a set temperature of 280 ° C. using an injection molding machine (J-100SAII manufactured by Nippon Steel). 6 mm). The obtained specimen is left in a constant temperature room at 23 ° C. and 50% humidity for 72 hours, and is subjected to UL94 test (flammability test of plastic materials for equipment parts) defined by Underwriters Laboratories. The compliant flame retardancy was evaluated, and V-0 or V-1 was determined to be acceptable. The results are shown in Tables 2-4. The flame resistance class of UL94 is as shown in Table 1.

  The after flame time is the length of time that the test piece after the ignition source is moved away from the flame, and the ignition of the cotton by the drip is for the sign about 300 mm below the lower end of the test piece. Of cotton is ignited by a drip from the specimen.

  When the resin composition satisfied the constituent requirements of the present invention (Examples 1 to 9), good results were shown over all the evaluation items.

On the other hand, in the case where the resin composition does not satisfy the constituent requirements of the present invention, each case had some drawbacks.
Comparative Example 1 was a case where the blending ratio of the branched polycarbonate resin was less than the range defined by the present invention, and was inferior in flame retardancy.
Comparative Example 2 was a case where the compounding amount of the silicone compound was less than the range of the present invention and was inferior in flame retardancy.
Comparative Example 3 was a case where the compounding amount of the silicone compound was larger than the range of the present invention, and was inferior in transparency.
Comparative Example 4 was a case where the compounding amount of the organic metal salt was less than the range defined by the present invention, and was inferior in flame retardancy.
In Comparative Example 5, the amount of the organic metal salt was larger than the range defined by the present invention, and the transparency was poor.

Claims (4)

A front panel for a liquid crystal television formed by molding a resin composition containing a branched polycarbonate resin as an essential component, wherein the resin composition is
(1) 100 parts by weight of a resin component consisting of 40 to 100% by weight of a branched polycarbonate resin (A) and 0 to 60% by weight of a linear polycarbonate resin (B), the main chain having a branched structure and containing an organic functional group 0.005 to 0.5 parts by weight of a silicone compound (C) consisting of an aromatic group or consisting of an aromatic group and a hydrocarbon group (excluding an aromatic group) and an organometallic salt (D) 0.005 The haze measured by using a test piece having a thickness of 3.0 mm obtained by molding the resin composition according to JIS K7361 is 2% or less. ,
An LCD TV front plate characterized by the above.   The organic metal salt (D) is one or more compounds selected from a metal salt of an aromatic sulfonic acid, a metal salt of a perfluoroalkanesulfonic acid, and a perfluoroalkanesulfonic acid imide. Item 2. A liquid crystal television front plate according to Item 1.   The liquid crystal television front plate according to claim 1, wherein the organometallic salt (D) is potassium perfluorobutanesulfonate.    The blending amount of the silicone compound (C) whose main chain has a branched structure and whose organic functional group contains an aromatic group, or which consists of an aromatic group and a hydrocarbon group (excluding an aromatic group) is 0.03. -0.3 parts by weight and the amount of the organometallic salt (D) is 0.04 to 0.1 parts by weight (each branched polycarbonate resin (A) 40 to 100% by weight and linear polycarbonate resin (B) The front plate for a liquid crystal television set according to claim 1, wherein (B) per 100 parts by weight of a resin component comprising 0 to 60% by weight).