JP3390665B2 - Antistatic polycarbonate resin composition, polycarbonate resin sheet laminate and base material for Fresnel lens - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an antistatic polycarbonate resin composition, a polycarbonate resin sheet laminate and a substrate for a Fresnel lens. More specifically, it is a substrate for a Fresnel lens of a projection television, which has excellent antistatic performance and also maintains excellent antistatic performance even after peeling the protective film in a polycarbonate resin sheet laminate in which a protective film is laminated. The present invention relates to a polycarbonate resin composition suitable for a material.

[0002]

2. Description of the Related Art Conventionally, a method of kneading various antistatic agents into a polycarbonate resin has been used for the purpose of preventing the polycarbonate resin from being charged. As such an antistatic agent, for example, metal salts of alkyl sulfonic acid, amine salts of alkyl sulfonic acid (Japanese Patent Laid-Open No. 3-6436)
8) and alkylphosphonic acid phosphonium salts (JP-A-62-230835, JP-A-64-14).
No. 267) has been proposed.

When the polycarbonate resin composition is used as a sheet, the surface is easily scratched, and therefore a protective film is generally attached to the surface.

However, the polycarbonate resin sheet containing the above antistatic agent initially has an excellent antistatic property, but when a protective film is attached and the protective film is peeled off after a certain period of time, the adhesiveness of the protective film is increased. It was found that the antistatic property of the polycarbonate resin sheet was significantly deteriorated due to the migration of the antistatic agent to the layer, and the antistatic property before attaching the protective film could not be maintained.

For example, a projection television screen (front plate) has a relatively low luminance as compared with a cathode ray tube type television, and in order to maintain the luminance,
The substrate for Fresnel lenses used is required to have excellent light diffusion and transparency. The applicant of the present application has developed a high-transmittance light diffusion plate made of a polycarbonate resin and previously proposed it (Japanese Patent Laid-Open No. 5-257002). Since organic particles are added, the surface of the diffuser plate has a fine uneven pattern, and dust and dust are accumulated on the surface of the diffuser plate with the passage of time, and the image is projected on the screen surface. However, it has a drawback that the image on the screen becomes dark due to a decrease in the transmittance.

Therefore, although a screen base material composed of a polycarbonate resin sheet in which the above antistatic agent is blended with this polycarbonate resin is proposed, as described above, such a screen base material initially has an antistatic property. However, there is a problem that the laminated protective film deteriorates the antistatic performance after the protective film is peeled off.

[0007]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The inventors of the present invention have found that a polycarbonate resin sheet laminate containing an antistatic agent in which a protective film is laminated, for example, in a substrate for a Fresnel lens of a projection television formed of the polycarbonate resin sheet As a result of repeated studies for the purpose of preventing the deterioration of the antistatic performance after peeling off the protective film of the resin sheet laminate, the use of tetrabutylphosphonium dodecylbenzenesulfonate as an antistatic agent in the polycarbonate resin, It was found that the antistatic performance is maintained even after peeling the protective film laminated on the polycarbonate resin sheet by using the fatty acid monoester together with the present invention, and arrived at the present invention.

[0008]

That is, according to the present invention, 100 parts by weight of a polycarbonate resin, 0.5 to 5 parts by weight of tetrabutylphosphonium dodecylbenzenesulfonate and the following formula (1) are used.

[0009]

[Chemical 2]

An antistatic polycarbonate resin composition comprising 0.1 to 1 part by weight of a fatty acid monoester represented by the formula (wherein R ¹ is an alkyl group having 12 to 20 carbon atoms) is provided. .

Further, according to the present invention, there is provided a polycarbonate resin sheet comprising the polycarbonate resin composition, wherein the polycarbonate resin sheet laminate has a protective film laminated on at least one surface of the sheet.

The polycarbonate resin used in the present invention is obtained by reacting a dihydric phenol with a carbonate precursor by a solution method or a melting method. A typical example of the dihydric phenol is 2,2-bis (4-hydroxyphenyl) propane [commonly called bisphenol A],
1,1-bis (4-hydroxyphenyl) ethane, 1,
1-bis (4-hydroxyphenyl) cyclohexane,
2,2-bis (3-methyl-4-hydroxyphenyl)
Propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl)
Examples thereof include sulfone, and among them, bisphenol A is preferable. These dihydric phenols may be used alone or in admixture of two or more.

As the carbonate precursor, carbonyl halide, carbonate ester, haloformate or the like is used, and specific examples thereof include phosgene, diphenyl carbonate or dihaloformate of dihydric phenol.

When a polycarbonate resin is produced by reacting the above-mentioned dihydric phenol with a carbonate precursor by a solution method or a melting method, a catalyst, a terminal stopper, an antioxidant for the dihydric phenol, etc. may be added, if necessary. May be used. Further, the polycarbonate resin may be a branched polycarbonate resin obtained by copolymerizing a trifunctional or higher polyfunctional aromatic compound, or a polyester carbonate resin obtained by copolymerizing an aromatic or aliphatic difunctional carboxylic acid, It may also be a mixture of two or more of the obtained polycarbonate resins.

The viscosity average molecular weight (M) of the polycarbonate resin is preferably 10,000 to 100,000, more preferably 15,000 to 35,000. Polycarbonate resin having such a viscosity average molecular weight,
Sufficient strength is obtained, and the melt fluidity at the time of molding is also favorable, which is preferable. The term "viscosity average molecular weight" as used in the present invention refers to 100 g of methylene chloride and 0.7 g of polycarbonate resin
The specific viscosity (η _sp ) obtained from the solution dissolved at 0 ° C. was inserted into the following equation. η _sp /c=[η]+0.45×[η] ² c (where [η] is the intrinsic viscosity) [η] = 1.23 × 10 ⁻⁴ M ^0.83 c = 0.7

The antistatic agent used in the present invention is tetrabutylphosphonium dodecylbenzene sulfonate. Even if a metal salt of alkylsulfonic acid or amine salt of alkylsulfonic acid is used as the antistatic agent, the object of the present invention is not achieved. Tetrabutylphosphonium dodecylbenzene sulfonate is a polycarbonate resin 1
0.5 to 5 parts by weight, preferably 1 to 100 parts by weight
The amount is 4.5 parts by weight, more preferably 2 to 4 parts by weight. If it is less than 0.5 parts by weight, a sufficient antistatic effect cannot be obtained, and if it exceeds 5 parts by weight, drawdown may occur during molding, and the resulting polycarbonate resin molded article may have poor mechanical properties, and thus may not be transparent. It is not preferable because the appearance is deteriorated.

The fatty acid monoester used in the present invention is the fatty acid monoester represented by the above formula (1), and specific examples thereof include stearic acid monoglyceride and lauric acid monoglyceride. The fatty acid ester is added in an amount of 0.1 to 1 part by weight, preferably 0.15 to 0.7 part by weight, and more preferably 0.2 to 0.5 part by weight, based on 100 parts by weight of the polycarbonate resin. It If the amount is less than 0.1 parts by weight, the antistatic performance after peeling off the protective film is deteriorated, and if the amount is more than 1 part by weight, foaming occurs during molding, and the mechanical properties of the obtained polycarbonate resin are deteriorated, which is not preferable. .

The protective film used in the polycarbonate resin sheet of the present invention has a thickness of 20 to 100 μm.
A transparent substrate such as polyethylene (PE) or polypropylene (PP) having an adhesive layer of 10 to 30 μm ethylene vinyl acetate copolymer (EVA) or PE oligomer is preferably used, and particularly a substrate made of PE. To EVA
Those having an adhesive layer of are preferably used. Further, the adhesive force between the polycarbonate resin sheet and the protective film is preferably 10 to 100 gf / 50 mm width. A protective film having an adhesive strength within such a range is preferable because it has a sufficient adhesive strength and thus functions as a protective film, and adhesive residue is less likely to occur when peeled off. Here, the adhesive strength is 50 m on the polycarbonate resin sheet.
At a temperature of 20 degrees in a protective film bonded with m width,
The edge of the protective film is perpendicular to the polycarbonate resin sheet (at a peeling angle of 90 degrees), and the peeling speed is 200 mm /
It is a value obtained by measuring the adhesive strength when peeled at a speed of a minute.

Furthermore, according to the present invention, 100 parts by weight of a polycarbonate resin, 0.5 to 5 parts by weight of tetrabutylphosphonium dodecylbenzenesulfonate, and the above formula (1) are used.
0.1 to 1 part by weight of a fatty acid monoester, 0.01 to 1 part by weight of a phosphorus-based antioxidant, and 0.01 of a light diffusing agent
Provided is a polycarbonate resin sheet comprising 0.5 to 0.5 parts by weight, and a polycarbonate resin sheet laminate having a protective film laminated on at least one surface of the sheet.

The polycarbonate resin sheet has a thickness of 0.2 to 2.0 mm and a surface resistivity of 1
Provided is a substrate for a Fresnel lens of a projection television, which has a light transmittance of less than 0 ¹⁵ Ω, a total light transmittance of 85% or more, and a haze of 5 to 30%.

As the phosphorus-based antioxidant used in the present invention, a phosphorous acid ester or a phosphoric acid ester is used.
Such phosphorous acid esters include, for example, triphenyl phosphite, trisnonylphenyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl. -Monophenyl phosphite, dioctyl-monophenyl phosphite, diisopropyl-monophenyl phosphite,
Monobutyl-diphenylphosphite, monodecyl-diphenylphosphite, monooctyl-diphenylphosphite, bis (2,6-di-tert-butyl-4-
Methylphenyl) pentaerythritol-di-phosphite, 2,2-methylenebis (4,6-di-tert-)
Butylphenyl) octylphosphite, bis (nonylphenyl) pentaerythritol-di-phosphite,
Bis (2,4-di-tert-butylphenyl) pentaerythritol-di-phosphite and tetrakis (2,4-di-tert-butylphenyl) -4,4-
A diester or monoester in which a triester or an ester portion of phosphorous acid such as diphenylenephosphonite is substituted with an alkyl group, a phenyl group, an alkylaryl group or the like, and these may be used alone or in combination of two or more kinds. Good. Of these, trisnonylphenyl phosphite is preferably used.

Examples of such phosphoric acid esters include tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate, trichlorophenyl phosphate, triethyl phosphate, diphenyl cresyl phosphate, diphenyl monoorthoxenyl phosphate, tributoxyethyl phosphate, dibutyl phosphate. , Dioctyl phosphate, diisopropyl phosphate and the like, and these may be used alone or in combination of two or more kinds. Further, the phosphorous acid ester and the phosphoric acid ester may be used in combination. Of these, trimethyl phosphate is preferably used.

The phosphorus-based antioxidant is 0.01 to 1 part by weight, preferably 0.015 to 0.7 part by weight, more preferably 0.1 to 1 part by weight based on 100 parts by weight of the polycarbonate resin.
It is compounded in the range of 02 to 0.5 parts by weight. When the blending amount of the phosphorus-based antioxidant is within such a range, the purpose of the antioxidant is achieved, the polycarbonate resin is not colored, and silver is less likely to occur during extrusion molding, and there is little risk of foaming. Become.

The light diffusing agent used in the present invention may be inorganic particles or organic particles generally used for a plastic light diffusing plate. For example, silica-alumina clay minerals (hydrous aluminum silicates) typified by kaolin. , Silica magnesium-based clay minerals represented by talc (hydrated magnesium silicates), calcium carbonate, barium sulfate, calcium silicate, silica alumina and the like. Further, as the organic particles, a crosslinked polyacrylate having a crosslinked structure,
Examples include crosslinked polystyrene. Among them, calcium carbonate, barium sulfate, crosslinked polyacrylate and crosslinked polystyrene are preferable because of excellent dispersion in the polycarbonate resin, and calcium carbonate and crosslinked polyacrylate are particularly preferably used. Such a light diffusing agent may be added in an amount of 0.01 to 0.
The amount is 5 parts by weight, preferably 0.03 to 0.3 parts by weight, more preferably 0.05 to 0.1 parts by weight.
When the compounding amount of the light diffusing agent is within such a range, the haze becomes 5% or more and the diffusing performance becomes sufficient, and the total light transmittance is 85% or more and the haze becomes 30% or less,
It has a bright screen and is preferable as a base material for a Fresnel lens of a projection television. The average particle size of the light diffusing agent is preferably in the range of 5 to 50 μm. A light diffusing agent having an average particle diameter within such a range is preferable because it is stable in the biting of the screw when blended with the polycarbonate resin and melt-extruded.

The projection television to which the present invention pertains has an optical unit such as a projection type projector inside the main body, and the light emitted from this optical unit is reflected by a mirror, and a Fresnel lens for suppressing the luminance unevenness of the screen. , Is projected onto a screen (front plate) through a lenticular lens for matching light and improving brightness. The surface of such a Fresnel lens is UV.
It consists of a resin-processed Fresnel lens part and a high-light-transmitting / diffusing substrate, and the light reflected from the mirror is uniformly diffused over the entire screen, and it is possible to suppress unevenness in brightness that occurs at the edges of the screen. The schematic configuration of the screen (front plate), Fresnel lens, and lenticular lens of this projection television is shown in FIGS. 1 and 2.

The substrate for a Fresnel lens of a projection television made of a polycarbonate resin in the present invention preferably has a thickness of 0.2 to 2.0 mm.
A base material having a thickness within this range has sufficient strength and is preferable in the perspective performance. Further, a substrate having a surface specific resistance of less than 10 ¹⁵ Ω is preferable. A base material having a surface resistivity within this range can sufficiently prevent dust and dirt from adhering and accumulating. A substrate having a total light transmittance of 85% or more is preferable. A substrate having a total light transmittance within this range has sufficient screen brightness. Further, a base material having a haze of 5 to 30% is preferable. A substrate having a haze within this range is preferable because the amount of transmitted light and the brightness of the screen are sufficient.

In the polycarbonate resin and the polycarbonate resin sheet of the present invention, a colorant, a flame retardant, and an agglomeration inhibitor may be blended within a range not impairing the objects and effects of the present invention.

The polycarbonate resin sheet and the substrate for a Fresnel lens of a projection television of the present invention can be produced by a usual sheet production method, for example, a melt extrusion method using a T-die extruder. Specifically, a polycarbonate resin, a predetermined amount of tetrabutylphosphonium dodecylbenzene sulfonate, a fatty acid monoester or a phosphorus antioxidant, a light diffusing agent, and if necessary, the above additives, for example, a tumbler, A method of dry blending using a super mixer, Nauta mixer or the like, and then directly or once pelletizing and then forming into a sheet having a predetermined thickness by a T die extruder is adopted.

[0029]

The present invention will be further described with reference to the following examples. The parts in the examples are parts by weight, and the surface resistivity, dust adhesion, transparency (total light transmittance, haze), hue (heat resistance during molding), and screen screen evaluation are as follows. Followed the method.

(1) Surface resistivity PE protective film (thickness: 50 μm) having a surface resistivity of a sheet immediately after being molded by a T-die extruder and an adhesive layer (thickness: 10 μm) whose material is EVA on the surface of the sheet. With an adhesive force of 60 gf / 50 mm,
The surface resistivity of the sheet after peeling off the protective film after being left at room temperature for 1 month is SM-8 manufactured by Toa Denpa Kogyo KK
It was measured with a 210 hyper-insulator. The smaller the value, the better the antistatic performance.

(2) Dust adhesion The dust adhesion was determined by visually observing the degree to which dust adheres by cutting the sheet into 950 × 1300 mm and suspending it in a room for 2 months. O indicates that dust adhesion was hardly seen, and X indicates that dust adhered to the sheet and the sheet looked cloudy.

(3) Transparency (total light transmittance, haze) Transparency has a thickness of 1.0 mm, a width of 60 mm, and a length of 80 mm.
The total light transmittance (Tt) and haze of the molded plate of No. 2 were measured by NDH-Σ80 manufactured by Nippon Denshoku Co., Ltd. A larger numerical value of total light transmittance indicates higher transparency, and a larger numerical value of haze indicates higher light diffusion.

(4) Hue (Heat resistance during molding) As for hue, the b value of a molded plate having a thickness of 1.0 mm, a width of 60 mm and a length of 80 mm was measured by a color difference meter manufactured by Nippon Denshoku Co., Ltd. The larger the b value, the worse the heat resistance.

(5) Screen screen The sheets obtained in the examples and comparative examples were used as a base material for a Fresnel lens of a projection television. The brightness and sharpness of the screen of a projection television using these screens were visually evaluated. O indicates that the screen is bright and clear even after long-term use, and X indicates that the screen becomes dark and unclear after the initial use or long-term use.

Examples 1 to 7 and Comparative Examples 1 to 7 Polycarbonate resin 10 having a viscosity average molecular weight of 24,500 produced from bisphenol A and phosgene by a solution method.
In 0 parts, the antistatic agent, fatty acid monoester shown in Table 1,
The phosphorus-based antioxidant and the light diffusing agent are blended in the amounts shown in Table 1,
After mixing with a tumbler, a sheet with a thickness of 1.0 mm and a width of 1000 mm is 280 with a T-die extruder having a diameter of 120 mm.
Molded at ° C. The characteristic values of the obtained sheet are shown in Table 1. The symbols showing each component in Table 1 are as follows. A-1; tetrabutylphosphonium dodecylbenzenesulfonate A-2; sodium dodecylbenzenesulfonate A-3; dodecylbenzenesulfonate didodecylmethylamine B-1; stearic acid monoglyceride B-2; lauric acid monoglyceride C-1; Calcium carbonate C-2; crosslinked polyacrylate D-1; trisnonylphenyl phosphite D-2; trimethyl phosphate

[0036]

[Table 1]

[0037]

The polycarbonate resin sheet comprising the polycarbonate resin composition of the present invention maintains the antistatic performance even after the protective film is attached and peeled off, and the surface resistivity is 1 × 10 ^15. When it is less than Ω, dust adhesion is hardly seen, and it is extremely useful as a base material for an inexpensive and excellent Fresnel lens of a projection television.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a screen portion of a projection television.

FIG. 2 is a schematic sectional view of a screen portion of a projection television.

[Explanation of symbols]

1. Projection television screen (front panel) 2. Lenticular lens 3. Fresnel lens 4. Base material for Fresnel lenses (diffusion sheet)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C08K 5/5398 C08K 5/5398 G02B 1/04 G02B 1/04

Claims (5)

(57) [Claims] 1. Polycarbonate resin 100 parts by weight, tetrabutylphosphonium dodecylbenzene sulfonate 0.5 to 5 parts by weight and the following formula (1): (In the formula, R ¹ is an alkyl group having 10 to 20 carbon atoms.) An antistatic polycarbonate resin composition comprising 0.1 to 1 part by weight of a fatty acid monoester. 2. A polycarbonate resin sheet comprising 100 parts by weight of a polycarbonate resin, 0.5 to 5 parts by weight of tetrabutylphosphonium dodecylbenzenesulfonate and 0.1 to 1 parts by weight of a fatty acid monoester represented by the above formula (1). A polycarbonate resin sheet laminate having a protective film laminated on at least one surface of the sheet. 3. 100 parts by weight of a polycarbonate resin, 0.5 to 5 parts by weight of tetrabutylphosphonium dodecylbenzenesulfonate, 0.1 to 1 parts by weight of a fatty acid monoester represented by the above formula (1), and a phosphorus-based antioxidant. 0.01 ~
A polycarbonate resin sheet laminate comprising 1 part by weight and 0.01 to 0.5 parts by weight of a light diffusing agent, the polycarbonate resin sheet laminate having a protective film laminated on at least one surface of the sheet. 4. The polycarbonate resin sheet laminate according to claim 3, wherein the light diffusing agent is at least one light diffusing agent selected from the group consisting of calcium carbonate, barium sulfate, crosslinked polyacrylate and crosslinked polystyrene. 5. The polycarbonate resin sheet according to claim 3, wherein the thickness is 0.2 to 2.0 mm, the surface specific resistance is less than 10 ¹⁵ Ω, the total light transmittance is 85% or more, and the haze is 5 to 30. % Base material for Fresnel lens of projection television.