JP2007212373A - Method for detecting surface defect of light-transmitting resin plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily detecting surface defects of light-transmitting resin plates, which are difficult to detect by visual inspection and are detected as irregular, recession-like, and other defects, after the formation of a hard coating layer. <P>SOLUTION: A liquid of which the refractive index n satisfies Expression (1) is applied to a light-transmitting resin plate in the method for detecting surface defects of light-transmitting resin plates. n<SB>0</SB>-0.1≤n (1) (where n<SB>0</SB>is the refractive index of the light-transmitting resin plate; and n is the refractive index of the liquid to be applied.) At this time, a liquid of which vapor pressure is 3 kPa or lower at normal temperatures is prefred, since this enables visualization of defects over a long period. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for detecting a surface defect of a translucent resin plate. More specifically, the present invention relates to a method for easily detecting defects such as a cocoon skin shape and a dent shape on the surface of a translucent resin plate that are difficult to detect visually.

Hard coat plates with a hard coat layer on a translucent resin plate and antistatic hard coat plates with anti-glare properties are widely used as display materials such as front plates for video display devices such as projection televisions. ing.
These hard coat plates are manufactured by applying a curable film to a translucent resin plate and curing it by heating or the like (see, for example, Patent Document 1 and Patent Document 2).

Inspection of surface defects of these hard coat plates is often performed visually, but is not detected in the permeable resin plate before applying the curable coating, but is caused by the permeable resin plate that forms the hard coat layer. Surface defects such as cocoon skin and dents may be visualized.
In particular, in the case of an antistatic hard coat plate having an antiglare property, the transparent resin plate for forming the hard coat layer is, for example, a plate-like shape in a heated and melted state using a roll having irregularities on the surface. Extrusion roll transfer molding method in which irregularities are formed on the surface of the resin immediately after being extruded, injection molding method in which resin is injected and molded into a mold having irregularities on the inner surface, raw material in a cell having irregularities on the inner surface A casting method for polymerizing the body, an insoluble resin particle is dispersed in a thermoplastic resin to obtain a thermoplastic resin composition, and this is heated and extruded to form a molten state and extrude from a die to provide fine irregularities on the surface. In particular, it is difficult to visually detect surface defects of the translucent resin plate before the hard coat layer is formed.

If a surface defect is detected after the hard coat layer is formed, it is a loss of materials and products. Even if a hard coat layer is formed and a surface defect is detected, a dryer or UV irradiation device is used. The method of detecting the surface defect of the permeable resin board before forming a hard-coat layer is desired, requiring the facilities, such as these, and much time and effort.
JP 2003-311891 A JP 2005-95870 A

  An object of the present invention is to provide a method for easily detecting a surface defect of a translucent resin plate which is difficult to detect visually and is detected as a defect such as a cocoon skin shape or a dent after forming a hard coat layer. There is.

As a result of intensive studies on a method for easily detecting the surface defect of the translucent resin plate,
The present inventors have found that the surface defects of the translucent resin plate can be easily detected simply by applying a liquid having a refractive index of 0.1 or more smaller than the refractive index of the translucent resin plate.
That is, the present invention is a method for detecting a surface defect of a translucent resin plate, wherein a liquid having a refractive index n satisfying the following formula (1) is applied to the translucent resin plate.
n ₀ −0.1 ≦ n (1)
(In the formula, n ₀ represents the refractive index of the translucent resin plate, and n represents the refractive index of the liquid to be applied.)
By this method, it becomes possible to easily detect the surface defect of the translucent resin plate.
Further, in the above detection method, the vapor pressure of the liquid at room temperature is 3 kPa or less.
By this method, defects can be detected visually over a long period of time.

  By the method of the present invention, it is difficult to detect visually, and it is possible to easily detect surface defects of the translucent resin plate that are detected as defects such as a cocoon skin shape and a dent shape after the hard coat layer is formed. Curing treatment is unnecessary, and therefore equipment such as a dryer and a UV irradiation device is unnecessary, and inspection time and labor can be shortened.

  The translucent resin plate in the method of the present invention is composed of a thermoplastic resin, and the thermoplastic resin is usually mainly composed of a highly transparent thermoplastic resin. Examples of the thermoplastic resin include acrylic resins such as methyl methacrylate polymer, methyl methacrylate-methyl acrylate copolymer, methyl methacrylate-styrene copolymer, methyl methacrylate-styrene-butadiene copolymer. And polycarbonate resins and the like, and resins containing two or more of these resins are also included. These resins may be rubber reinforced, and various additives such as light diffusing agents, antioxidants, plasticizers, mold release agents, colorants, antistatic agents, ultraviolet absorbers, flame retardants, etc. May be one or more added depending on the purpose.

  The resin plate is used for various applications, and forms an optical screen such as a transmission screen of a projection television. For example, a sheet-like screen component such as a Fresnel lens sheet, a lenticular lens sheet, and a front panel It is also used for sheet-like base materials used as so-called original plates when manufacturing them.

Moreover, the translucent resin plate in the method of the present invention may be provided with antiglare properties by providing fine irregularities on the surface. This antiglare resin plate is formed by, for example, an extrusion roll transfer molding method in which an uneven surface is provided on the surface of a resin immediately after being extruded into a plate shape from a die in a heated and melted state using a roll having an uneven surface. It is manufactured by an injection molding method in which a resin is injected and molded into a mold having irregularities, and a casting molding method in which a raw material monomer is polymerized in a cell having irregularities on the inner surface.
It can also be produced by an extrusion method in which insoluble resin particles are dispersed in a thermoplastic resin to obtain a thermoplastic resin composition, which is heated and extruded from a die in a molten state. The extruded thermoplastic resin composition extruded from the die has fine irregularities formed by insoluble resin particles on the surface thereof, thereby imparting antiglare performance.

These translucent resin plates may be used by processing a functional film such as a hard coat on one or both surfaces of the surface.
The hard-coated plate having anti-glare properties is, for example, the forefront of an image display device such as a cathode ray tube (CRT), a liquid crystal display device (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), or a light emitting diode display. It is useful as a front plate to be disposed on. Moreover, it is used also as a front plate arrange | positioned at the forefront of a projection television.

  The hard coat plate is obtained by dissolving the hard coat agent in an organic solvent, for example, a dip coat method in which the entire antiglare resin plate is immersed in the treatment liquid, and a spray coat method in which the treatment liquid is sprayed and adhered to the surface of the resin plate. A hard coat agent is applied by a coating method such as a bar coating method or a roll coating method in which a surface treatment liquid is stretched by a bar or roll on a resin plate, dried and then cured.

  As the hard coating agent, various types of energy ray curable hard coating agents that are cured by irradiation with energy rays such as ultraviolet rays and various thermosetting hard coating agents that are cured by heating are known. However, for example, when the resin constituting the resin plate is a methyl methacrylate-styrene copolymer (MS resin), it contains a curable compound having an aromatic ring and a (meth) acryloyloxy group in the molecule. A hard coat agent having 3 or more (meth) acryloyloxy groups per aromatic ring, a curable compound having an aliphatic ring and a (meth) acryloyloxy group in the molecule, and A hard coating agent containing a curable compound having three or more (meth) acryloyloxy groups or an oligomer thereof is preferably used. It is. Moreover, what disperse | distributed inorganic fillers, such as an antimony oxide, is used.

  The curing process varies depending on the type of hard coat agent. When an energy ray curable hard coat agent is used, it is irradiated with energy rays, and when a thermosetting hard coat agent is used, it is heated. Done.

  When the hard coat layer is formed, surface defects such as a cocoon skin shape and a dent shape may be visualized due to the transparent resin plate that is not detected before the hard coat layer is formed.

In this invention, the surface defect of a translucent resin board is detected by apply | coating the liquid whose refractive index n satisfies following Formula (1) to a translucent resin board.
n ₀ −0.1 ≦ n (1)
(In the formula, n ₀ represents the refractive index of the translucent resin plate, and n represents the refractive index of the liquid to be applied.)
Preferably, by applying a liquid that satisfies the following formula (2), it becomes easier to visually detect defects.
n ₀ −0.07 ≦ n (2)
The upper limit of the refractive index n of the liquid to be applied is not particularly limited, but usually n ≦ 1.87, preferably n ≦ 1.71.
Specifically, for example, when the resin plate is 1.53, a liquid having a refractive index of 1.43 or more, more preferably 1.46 or more is used.

  In addition, liquids that are likely to volatilize are volatilized and defects are difficult to see in a short time. Therefore, liquids that are difficult to volatilize are desirable. It is desirable to use those.

  Furthermore, it is desirable that the liquid on the surface does not repel after application to the resin plate, and a liquid having a surface tension equal to or less than the surface tension of the resin plate is preferably used.

Specific examples of the liquid to be used include the following, but are not limited thereto. In addition, p shows the vapor pressure in normal temperature.
Dimethyl phthalate (n: 1.517 (20 ° C), p: 0.1 kPa or less), diethyl phthalate (n: 1.499 (25 ° C), p: 0.1 kPa or less), dibutyl phthalate (n: 1.493 (20 ° C.), p: 0.1 kPa or less, bis (2-ethylhexyl) phthalate (n: 1.486 (20 ° C.), p: 0.1 kPa or less), dioctyl phthalate (n: 1 482 (25 ° C.), p: 0.1 kPa or less), dibutyl sebacate (n: 1.440 (25 ° C.), p: 0.1 kPa or less), bis (2-ethylhexyl) sebacate (n: 1. 449 (25 ° C.), p: 0.1 kPa or less), tributyl citrate (n: 1.431 (25 ° C.), p: 0.1 kPa or less), dibutyl tartrate (n: 1.463 (20 ° C.), p : 0.1 kPa or less), dimethyl maleate (n: .441 (25 ° C.), p: 0.1 kPa or less), diethyl maleate (n: 1.439 (25 ° C.), p: 0.29 kPa), dibutyl maleate (n: 1.444 (25 ° C.)), p: 0.1 kPa or less), γ-butyllactone (n: 1.435 (25 ° C.), p: 0.1 kPa or less), bis (2-ethylhexyl) adipate (n: 1.447 (25 ° C.), p: 0.1 kPa or less), benzyl abietic acid (n: 1.551 (15 ° C.), p: 0.1 kPa or less), ethyl cinnamate (n: 1.560 (20 ° C.), p: 0.1 kPa ), Methyl benzoate (n: 1.518 (16 ° C.), p: 0.1 kPa or less), ethyl benzoate (n: 1.507 (17 ° C.), p: 0.1 kPa or less), propyl benzoate (N: 1.500 (20 ° C.), p: 0.1 kPa or less), Butyl benzoate (n: 1.494 (25 ° C), p: 0.1 kPa or less), isopentyl benzoate (n: 1.696 (15 ° C), p: 0.1 kPa or less), benzyl benzoate (n : 1.568 (21 ° C), p: 0.1 kPa or less, butyl stearate (n: 1.446 (20 ° C), p: 0.1 kPa or less), benzyl acetate (n: 1.523 (20 ° C) ), P: 0.1 kPa or less), cyclohexyl acetate (n: 1.442 (20 ° C.), p: 0.1 kPa or less), glycerin monoacetate (n: 1.448 (25 ° C.), p: 0. 1 kPa or less), glycerin triacetate (n: 1.431 (20 ° C.), p: 0.1 kPa or less), glycerin monobutyrate (n: 1.450 (24 ° C.), p: 0.1 kPa or less), Furfuryl alcohol (n: 1.487 (20 ° C), p: 0.1 kPa or less, triethyl phosphate (n: 1.495 (25 ° C), p: 0.1 kPa or less), o-tricresyl phosphate (n: 1.559 (25 ° C)), p : 0.1 kPa or less), tricresyl m-phosphate (n: 1.553 (25 ° C.), p: 0.1 kPa or less), 2-phenoxyethanol (n: 1.539 (20 ° C.), p: 0.1 kPa Or less), 2- (benzyloxy) ethanol (n: 1.523 (20 ° C.), p: 0.1 kPa or less), tetrahydrofurfuryl alcohol (n: 1.452 (20 ° C.), p: 0.1 kPa) , Diethylene glycol (n: 1.448 (20 ° C.), p: 0.1 kPa or less), triethylene glycol monomethyl ether (n: 1.438 (20 ° C.), p: 0.1 kPa or less), polyethylene glycol 200 n: 1.659 (25 ° C.), p: 0.1 kPa or less), polyethylene glycol 300 (n: 1.463 (25 ° C.), p: 0.1 kPa or less), polyethylene glycol 400 (n: 1.465 ( 25 ° C.), p: 0.1 kPa or less), polyethylene glycol 600 (n: 1.467 (25 ° C.), p: 0.1 kPa or less), dipropylene glycol (n: 1.440 (20 ° C.), p: 0.1 kPa or less), polypropylene glycol diol 400 (n: 1.445 (25 ° C.), p: 0.1 kPa or less), polypropylene glycol 750 (n: 1.447 (25 ° C.), p: 0.1 kPa or less ), Polypropylene glycol diol 1200 (n: 1.448 (25 ° C.), p: 0.1 kPa or less), polypropylene glycol diol 2000 (N: 1.450 (25 ° C.), p: 0.1 kPa or less), polypropylene glycol triol 3000 (n: 1.452 (25 ° C.), p: 0.1 kPa or less), 2-chloroethanol (n: 1 .442 (20 ° C.), p: 0.65 kPa), 1-chloro-2-propanol (n: 1.436 (20 ° C.), p: 0.65 kPa), 3-chloro-1,2-propanediol ( n: 1.481 (20 ° C.), p: 0.1 kPa or less), 1,3-dichloro-2-propanol (n: 1.484 (20 ° C.), p: 0.1 kPa or less), diethanolamine (n: 1.475 (30 ° C.), p: 0.1 kPa or less, N-butyldiethanolamine (n: 1.462 (20 ° C.), p: 0.1 kPa or less), triethanolamine (n: 1.485 (20 ° C), p: 0.1 Pa or less), isopropanolamine (mixture) (n: 1.520 (20 ° C.), p: 0.1 kPa or less), furfural (n: 1.526 (20 ° C.), p: 0.3 kPa), epichlorohydride Phosphorus (n: 1.438 (20 ° C.), p: 1.7 kPa or less), o-nitroanisole (n: 1.562 (20 ° C.), p: 0.1 kPa or less), morpholine (n: 1.454) (20 ° C.), p: 0.9 kPa), lactic acid (n: 1.439 (20 ° C.), p: 0.1 kPa or less), methyl salicylate (n: 1.538 (18 ° C.), p: 0.1 kPa ), 2-phenoxyethyl acetate (n: 1.501 (20 ° C.), p: 0.1 kPa or less), dichloroacetic acid (n: 1.466 (22 ° C.), p: 0.1 kPa or less), o -Chloroaniline (n: 1.588 (20 ° C), p: 0) 1 kPa or less), hexamethylphosphoric triamide (n: 1.458 (20 ° C), p: 0.1 kPa or less), ethylbenzene (n: 1.696 (20 ° C), p: 1.3 kPa), 2-ethyl -1-hexanol (n: 1.433 (20 ° C.), p: 0.1 kPa or less), 3,5,5-trimethyl-1-hexanol (n: 1.433 (20 ° C.), p: 0.1 kPa 1) -decanol (n: 1.437 (20 ° C.), p: 0.1 kPa or less), 1-undecanol (n: 1.440 (20 ° C.), p: 0.1 kPa or less), propargyl alcohol ( n: 1.431 (20 ° C.), p: 0.1 kPa or less), benzyl alcohol (n: 1.540 (20 ° C.), p: 0.1 kPa or less), cyclohexanol (n: 1.465 (25 ° C.) ), P: 0.1 kPa), a Ethinol (n: 1.535 (20 ° C.), p: 0.1 kPa or less), 1,2-propanediol (n: 1.433 (20 ° C.), p: 0.1 kPa or less), 1,3-propane Diol (n: 1.439 (20 ° C.), p: 0.1 kPa or less), 1,4-butanediol (n: 1.445 (25 ° C.), p: 0.1 kPa or less), 2,3-butane Diol (n: 1.432 (35 ° C.), p: 0.1 kPa or less), 1,5-petanediol (n: 1.450 (20 ° C.), p: 0.1 kPa or less), 2-butene-1 , 4-diol (n: 1.472 (25 ° C), p: 0.1 kPa or less), 2-ethyl-1,3-hexanediol (n: 1.451 (20 ° C), p: 0.1 kPa or less) ), Glycerin (n: 1.475 (15 ° C.), p: 0.1 kPa or less), 1,2,6- Hexanetriol (n: 1.477 (20 ° C), p: 0.1 kPa or less), phenol (n: 1.542 (41 ° C), p: 0.1 kPa or less), mesityl oxide (n: 1.446) (20 ° C.), p: 0.1 kPa, holon (n: 1.500 (20 ° C.), p: 0.1 kPa or less), isophorone (n: 1.478 (20 ° C.), p: 0.1 kPa or less) ), Cyclohexanone (n: 1.451 (20 ° C), p: 0.5 kPa), methylcyclohexanone (n: 1.449 (20 ° C), p: 0.1 kPa or less), acetophenone (n: 1.536 ( 20 ° C.), p: 0.1 kPa or less), oleic acid.

(N: 1.460 (20 ° C.), p: 0.1 kPa or less), toluene (n: 1.497 (20 ° C.), p: 3.7 kPa), o-xylene (n: 1.503 (25 ° C.) ), P: 0.8 kPa), m-xylene (n: 1.495 (25 ° C), p: 1 kPa), p-xylene (n: 1.493 (25 ° C), p: 1 kPa or less).
When the viscosity of these liquids is high, it is also possible to dilute with a highly volatile solvent for the purpose of improving the handleability.

  The application method to the resin plate is not particularly limited, and a commonly applied application method such as a spray method, a dipping method, a roll coating method, a flow coating method, a gravure coating method, a spin coating method, a die coating method, or the like is known. It can be done by the method.

  By simply applying the above liquid to the resin plate, surface defects that have not been visually detected can be visually detected.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.

Example 1
When the hard coat layer is formed, an anti-glare resin plate A (n ₀ : 1.53) in which a defect that looks like a cocoon skin is detected, and when the hard coat layer is formed, a defect that looks like a dent is detected. Dibutyl phthalate (n: 1.493 (20 ° C.), p: 0.1 kPa or less) was applied to each of the antiglare substrates B (n ₀ : 1.53) by a dipping method at a pulling rate of 5 mm / sec. Thereafter, the defects were visually detected immediately after standing at room temperature for 3 hours. The results are shown in Table 1.

Example 2
In the same manner as in Example 1, diethyl maleate (n: 1.439 (25 ° C.), p: 0.29 kPa) was applied to each of the antiglare substrate A and the antiglare substrate B, and defects were visually observed. Was detected. The results are shown in Table 1.

Example 3
In the same manner as in Example 1, toluene (n: 1.497 (20 ° C.), p: 3.7 kPa) was applied to each of the anti-glare substrate A and the anti-glare substrate B, and defects were detected visually. Went. The results are shown in Table 1.

Comparative Example 1
In the same manner as in Example 1, dipropylene glycol monomethyl ether (n: 1.419 (25 ° C.), p: 0.1 kPa or less) was applied to the anti-glare substrate A and the anti-glare substrate B, respectively. The defect was detected. The results are shown in Table 1.

○；検出できた。
×；検出できなかった。

○: Detected.
X: It was not detected.

Claims (2)

A method for detecting a surface defect of a translucent resin plate, wherein a liquid having a refractive index n satisfying the following formula (1) is applied to the translucent resin plate.
n ₀ −0.1 ≦ n (1)
(In the formula, n ₀ represents the refractive index of the translucent resin plate, and n represents the refractive index of the liquid to be applied.) 2. The detection method according to claim 1, wherein the vapor pressure of the liquid at room temperature is 3 kPa or less.