JPH11170449A - Acrylic resin laminate of crystal tone frost glass appearance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acrylic resin laminate not spoiling the glass tone touch on the sheet surface even when thermoforming is carried out, and preventing defects generated by adding a large amount of additive, in which the total beam transmittance, haze and light diffused transmittance are so controlled as to be within a certain range, and the transparent touch of crystal glass and the profound touch of frost glass are provided combinedly. SOLUTION: The total beam transmittance of a laminate is 70% or more, and the haze is 80% ore more and the light diffused transmittance is 10% or more, and the laminate is constituted of acrylic resin layers composed of 99-70 wt.% acrylic resin A blended with 1-30 wt.% spherical fine particles B of the 0.02-0.2 absolute value of refractive index difference from the acrylic resin and of 1-100 μm weight average particle diameter laminated on either one of both faces of a base layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic resin laminate having the appearance of crystal polished glass.

[0002]

2. Description of the Related Art Acrylic resin has transparency, surface hardness,
Excellent moldability, weatherability, etc., vehicle exterior parts such as lighting fixture covers and tail lamps, optical parts such as lenses, light guide plates, video discs, projection TV screens, vending machine front panels, outdoor signs, stores It is widely used for applications such as instrument displays.

[0003] Among them, in the field of lighting covers, there is a great demand for various lighting cover materials provided with decorativeness in accordance with diversified lighting. As a method of imparting a frosted glass texture to the sheet surface, a method of transferring fine irregularities to the sheet surface using a mat roll as a polishing roll at the time of producing an extruded sheet, calcium carbonate, talc,
A method of blending an inorganic powder such as mica and molding the same is generally disclosed.

[0004] However, the sheet obtained by the transfer of the mat roll loses the uneven surface by thermoforming, and as a result, loses its glassy appearance. In addition, in the method using the additive as described above, it is necessary to add a large amount of an additive in order to form a glassy state, a reduction in total light transmittance and a loss of transparency are impaired. It has been difficult to achieve the texture of crystal polished glass with the desired transparency.

[0005]

SUMMARY OF THE INVENTION The present invention does not impair the glass tone of the sheet surface even when thermoforming is performed, and further prevents the drawbacks caused by adding a large amount of additives.
The purpose of the present invention is to provide an acrylic resin laminate that is adjusted so that the total light transmittance, haze, and light diffusivity are within a certain range, and has both a transparent texture of crystal glass and a heavy texture of polished glass. It is.

[0006]

Means for Solving the Problems In view of the above-mentioned situation, the present inventor has made intensive studies and found that the total light transmittance of the laminated plate was 7%.
It has been found that by adjusting the haze to 80% or more and the light diffusivity to 10% or more, an acrylic resin laminate having the appearance of crystal polished glass can be obtained. I came to.

That is, the present invention is as follows. 1) The total light transmittance of the laminate is 70% or more, and the haze is 80%
As described above, the light diffusivity is 10% or more, and the structure of the laminate is such that the acrylic resin (A) is 99 to 70% by weight and the absolute value of the refractive index difference between the acrylic resin (A) and the acrylic resin (A) is 0.02 to 0%. And an acrylic resin layer (a) containing 1 to 30% by weight of spherical fine particles (B) having a weight average particle diameter of 1 to 100 μm, and a substrate layer made of an acrylic resin (b).
An acrylic resin laminate having the appearance of crystal polished glass, which is laminated on one or both sides of the above.

2) The acrylic resin laminate having the appearance of crystal polished glass according to the above item 1, wherein the spherical fine particles (B) are crosslinked siloxane resin fine particles and / or crosslinked styrene resin fine particles. 3) The spherical fine particles further have an absolute value of a difference in refractive index from the acrylic resin (A) of less than 0.02, a weight average particle size of at least twice the spherical fine particles (B), and at least 20 μm. 3. An acrylic resin laminate having the appearance of a crystal polished glass according to the above 1 or 2, wherein 1 to 20 parts by weight of the spherical acrylic crosslinked resin fine particles are blended with respect to the acrylic resin layer (a). Board.

4) A lighting cover using an acrylic resin laminate having the appearance of the crystal-polished glass according to the above item 1, 2 or 3. In the present invention, the crystal polished glass texture means a texture obtained by applying a matte finish to a transparent crystal glass. The total light transmittance is 70% or more, the transmittance is high, the haze is 80% or more, and the light diffusivity is high. Indicates a texture satisfying a characteristic of 10% or more.

In the present invention, the acrylic resin layer (a) is laminated on the surface layer of the acrylic resin substrate layer (b), and the thickness of the laminated portion and / or the thickness of the substrate portion is arbitrarily controlled. This gives a crystal-polished glass plate with a tint of. In addition, the laminated plate of the present invention does not decrease productivity due to imparting a crystal polished glass texture, can minimize cost increase due to additives, and is economically excellent. The industrial application range is large.

Hereinafter, the present invention will be described in more detail. The laminate of the present invention has a total light transmittance of 70% or more and a haze of 8
It has optical characteristics in a range of 0% or more and a light diffusion rate of 10% or more. When the total light transmittance is less than 70%, a clear transparent texture is insufficient. When the haze is less than 80%, a white color close to crystal polished glass cannot be obtained. When the light diffusivity is less than 10%, a lighting cover. When mounted on a light source device, the lamp shape of the light source is undesirably reflected too much.

The spherical fine particles (B) in the present invention are fine particles having an absolute value of a difference in refractive index from the acrylic resin of 0.02 to 0.2 and a weight average particle diameter of 1 to 100 μm. For example, crosslinked siloxane-based resin fine particles, crosslinked styrene-based resin fine particles and the like can be mentioned, and these can be added alone or in combination. The absolute value of the refractive index difference from the acrylic resin and the weight average particle diameter vary depending on the application, purpose, and product image, but the absolute value of the refractive index difference is 0.02.
If it is less than the above, whiteness and diffusivity close to those of a crystal polished glass will be insufficient, and if it exceeds 0.2, the light transmittance will be low and it will be too white, which is not preferable. The weight average particle size is
If it exceeds 100 μm, the surface condition becomes poor, and if it is less than 1 μm, the matting effect of the surface layer is small, which is not preferable. Preferably it is 2 to 50 μm, more preferably 2 to 30 μm.

The spherical fine particles (B) are preferably crosslinked siloxane resin fine particles from the viewpoint of light-resistant coloring, but are not limited thereto. When the acrylic resin layer (a) used for the laminated portion is manufactured by using the laminate of the present invention, the acrylic resin (A) that can be mixed with the spherical fine particles (B) includes methyl methacrylate alone. A coalesced or copolymer of methyl methacrylate and another monomer is used.
80% by weight of methyl methacrylate structural unit in the copolymer
Those having the above are preferred.

The monomers copolymerizable with methyl methacrylate include ethyl methacrylate, butyl methacrylate,
Alkyl methacrylates such as cyclohexyl methacrylate; alkyl acrylates such as methyl acrylate, ethyl acrylate and butyl acrylate; aromatic vinyl compounds such as styrene, vinyltoluene and α-methylstyrene; acrylonitrile and methacrylic acid Vinyl cyanide compounds such as lonitrile, N-phenylmaleimide, maleimides such as N-cyclohexylmaleinide,
Examples include unsaturated carboxylic anhydrides such as maleic anhydride and itaconic anhydride, and unsaturated acids such as methacrylic acid, acrylic acid, and maleic acid.

The methacrylic acid or acrylic acid copolymer includes a copolymer obtained by heat-treating the methacrylic acid or acrylic acid to form a six-membered acid anhydride by a dehydration reaction or the like. These monomers copolymerizable with methyl methacrylate can be used alone or in combination of two or more. In the present invention, the acrylic resin described above can also be used as an acrylic resin that can be used for the substrate layer (b) of the laminate.

The method for producing such an acrylic resin is not particularly limited, and includes suspension polymerization, emulsion polymerization, bulk polymerization,
Alternatively, any of known methods such as solution polymerization may be used. As the polymerization initiator, a normal peroxide-based or azo-based radical polymerization initiator can be used, and this may be used as a redox-based initiator in combination with a reducing agent. An acrylic resin obtained by an anionic polymerization method using an alkyl lithium or the like, a coordination polymerization method using an organometallic complex, a group transfer polymerization method, or the like may be used. The polymerization temperature is generally 30 to 100 ° C for suspension polymerization or emulsion polymerization, and 80 to 170 ° C for bulk or solution polymerization. In order to control the reduced viscosity of the acrylic resin, it may be carried out using an alkyl mercaptan or the like as a chain transfer agent. In addition, an acrylic resin composition having impact resistance imparted by a multilayer acrylic rubber or the like can be used.

When the acrylic resin layer (a) used in the laminated portion is produced from the laminate of the present invention, the spherical fine particles (B) are contained in an amount of 1 to 30% by weight, preferably 3 to 25% by weight,
More preferably, 6 to 25% by weight and 70 to 99% by weight, preferably 75 to 97% by weight, more preferably 75 to 94% by weight of the acrylic resin (A) are used as a mixture. When the content of the spherical fine particles is less than 1% by weight, the resulting laminate has poor light diffusivity, which is not preferable. On the other hand, when the spherical fine particles exceed 30% by weight,
It is not preferable because the surface layer portion of the obtained laminated board becomes poor and the mechanical strength decreases.

When the spherical fine particles use crosslinked styrene resin fine particles, the content may be less than 1% by weight in consideration of light discoloration resistance and the like, and is preferably used in combination with other spherical fine particles. The mixing method for producing the acrylic resin layer (a) is not particularly limited. A method of mixing with a drum blender or a Henschel mixer, or mixing by these methods, and then using an extruder at 200 to 280 ° C.
Granulation at a temperature of, for example.

Acrylic resin (A) and spherical fine particles (B)
The purpose of adjusting the delicate surface texture of a laminated board without significantly affecting the total light transmittance, haze, and light diffusibility when producing an acrylic resin layer (a) by mixing Further, the absolute value of the difference in refractive index between the acrylic resin (A) and the acrylic resin (A) is less than 0.02 with respect to 100 parts by weight of the acrylic resin layer (A), and the weight average particle diameter is the spherical fine particles (B). 1 to 20 parts by weight of spherical crosslinked acrylic resin fine particles that are twice or more and 20 μm or more. The amount is preferably 2 to 15 parts by weight, more preferably 2 to 10 parts by weight. If the amount is less than 1 part by weight, the effect of improving the surface texture is not sufficiently obtained, and if it exceeds 20 parts by weight, the total light transmittance, haze and light diffusion tend to be greatly affected.

When the sheet is used, the inorganic transparent substance fine powder and / or
Alternatively, an inorganic pigment can be added. Examples of the fine inorganic transparent substance powder include calcium carbonate and barium sulfate, and examples of the inorganic pigment include titanium oxide. Further, when formed into a sheet, as long as the appearance is not impaired, for example, a heat stabilizer, a hindered phenol type as an antioxidant, a phosphate type, a benzotriazole type as a UV absorber, a 2-hydroxybenzophenone type, Salicylic acid phenyl ester type, triazine type, etc., phthalic acid ester type, fatty acid ester type, trimellitic acid ester type, phosphate ester type, polyester type etc. as plasticizers, higher fatty acids as mold release agents,
Higher fatty acid esters, higher fatty acid mono-, di-, or triglycerides, etc .; higher fatty acid esters, polyolefins, etc. as lubricants; phosphorus-based, phosphorus / chlorine, phosphorus / bromine-based, etc. as flame retardants; polyetheresteramides as antistatic agents; Elastomers such as polyalkylene glycol, polyetherester, and polyetherimidamide and an electrolyte auxiliary such as sodium alkylbenzene sulfonate are added to the acrylic resin layer (a) and the substrate layer (b).
May be arbitrarily mixed.

The method for producing the acrylic resin laminate having the appearance of crystal-polished glass texture of the present invention is not particularly limited, and a common co-extrusion method (co-extrusion method), a lamination method, or the like can be used. . When processing into a sheet, it is preferable to carry out the process at a resin temperature of 180 to 280 ° C. The co-extrusion method, which is one of the methods for producing the laminated board of the present invention, is capable of adjusting the fluidity of both layers during lamination and uniformity, so that the adhesion between the two layers is good and the molding distortion is small. Are better. In the co-extrusion method, usually, two or more extruders are used, an extruder of 40 mmφ, 60 mmφ, 90 mmφ or the like is used for the substrate resin, and a smaller 20 m is used for the laminated resin.
Using an extruder such as mφ, 30mmφ, 45mmφ,
It is common to extrude with an extrusion die. In general, the thickness adjustment of the lamination portion and the substrate portion is performed by adjusting the extrusion amount of each extruder and adjusting the interval between polishing rolls installed at the exit of the extrusion die. Further, in order to co-extrude the resin of the substrate portion and the resin of the laminated portion while adjusting the fluidity thereof, the temperature of each extruder may be adjusted to cope with the extrusion. Acrylic resin layer used for the laminated part (a)
It is generally preferable that the acrylic resin (A) and the spherical fine particles (B) are uniformly mixed in advance using a blender or the like, and then kneaded and pelletized by an extruder.

As another method, there is a laminating method. In the case of manufacturing by a laminating method, an acrylic resin layer (a) is preliminarily formed into a film having a desired thickness, and this and a substrate layer are extruded. It is a general method to form a laminated sheet having a constant thickness by laminating with a polishing roll at the outlet. In this case, the point is to prevent air from remaining when superimposed and to improve the adhesion by controlling the roll temperature.

The thickness of the laminated board of the present invention is generally 0.1.
Those having a size of 5 to 100 mm are used. The thickness of the laminated portion of the laminate of the present invention is 3 to 400 μm, preferably 5 to 400 μm.
３００300 μm, more preferably 10-200 μm. When the thickness of the laminated portion is less than 3 μm, the glass texture of the laminated plate is not always sufficient, while when the thickness of the laminated portion exceeds 400 μm, the mechanical strength of the laminated plate tends to decrease. Generally, the thickness of the laminated portion is preferably 30% or less of the total thickness of the sheet from the viewpoint of maintaining mechanical strength. Even when the laminated portions are provided on both surfaces of the substrate portion, the total thickness of the laminated portions is preferably 30% or less of the total thickness of the laminated plate.

The thickness of the laminated portion of the laminate can be measured by observing the cross section of the laminate with a differential interference microscope or an electron microscope. In order to facilitate the measurement of the thickness of the laminated portion during the production of the laminate, the acrylic resin layer (a) may contain a small amount of a dye or the like. The laminated plate of the present invention is a compressed air molding used for molding an acrylic resin plate,
It can be processed by a general forming method such as vacuum forming and free heat forming.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described more specifically with reference to Examples and Comparative Examples below, but the present invention is not limited thereto. The evaluation and test methods used are shown below. 1. The total light transmittance and haze were measured according to JIS K-7105.

2. Method for calculating light diffusivity Using a goniophotometer manufactured by Optes, each diffused light amount was measured with a parallel light beam diameter of 30 mmφ and a light receiving portion diameter of 10 mmφ, and the light diffusivity was calculated by the following equation. Light diffusion rate =
2. ((20 degree diffused light quantity + 70 degree diffused light quantity) / (5 degree diffused light quantity x 2)) x 100 In the thermoforming, vacuum forming was performed at a forming temperature of 160 ° C. using a hat-shaped vacuum forming die having a diameter of 100 mm and a height of 50 mm. Thereafter, the surface appearance before and after thermoforming was visually observed.

[0027]

[Example 1] Acrylic resin "Delpet L" manufactured by Asahi Kasei Corporation
90 parts by weight of "P-1 (A-1)" and 10 parts by weight of a spherical crosslinked siloxane-based resin fine particle "Tospearl 145: weight average particle diameter 4.5 μm (B-1)" manufactured by Toshiba Silicone Co., Ltd. were mixed with a drum blender, and 30 mm Using a twin screw extruder, the mixture was kneaded at a resin temperature of about 250 ° C. and granulated to obtain a resin composition for a laminated portion.

The obtained resin composition for a laminated portion is 30 mm
An extruder with φ, L / D = 24 was used, and the above-mentioned acrylic resin (A-1) was 90 mmφ, L / D
Co-extrusion was performed using an extruder with D = 32. The die uses a two-layer, two-layer feed block system, and adjusts the lip opening and the clearance of the polishing roll so that the thickness of the laminate becomes 2.5 mm. The temperature of the extruder and the die is 250 to 260 ° C. I went in. The control of the thickness of the laminated portion was adjusted by changing the discharge amount of an extruder of 30 mmφ and L / D = 24. When a laminate having a width of about 30 cm was manufactured in this manner, the total thickness of the laminate was 2.5 mm, and the thickness of the laminated portion was 100 μm.

A test piece was cut out from this sheet, and the total light transmittance, haze, and light diffusivity were measured. The following results were obtained. The total light transmittance was 89%, the haze value was 92%, and the light diffusivity was 20%. In addition, when the surface was visually observed, the surface showed the texture of crystal polished glass, and the texture was maintained after thermoforming.

[0030]

Examples 2 to 6 and Comparative Examples 1 to 5 Evaluations were made in the same manner as in Example 1 except that the type and amount of the spherical fine particles were changed. The above results are summarized in Table 1.

[0031]

[Table 1]

The annotations in Table 1 are as follows. B-1 Toshiba Silicone Co., Ltd. “Tospearl 145, weight average particle size 4.5 μm” B-2 Toshiba Silicone Co., Ltd. “Tospearl 2000”
B, weight average particle diameter 6.0 μm ”B-3 talc“ weight average particle diameter 10 μm ”B-4 barium sulfate B-5 Sekisui Plastics Co., Ltd.“ Techpolymer SBX ”
4. Weight average particle size 4 μm ”B-6 Sekisui Plastics Co., Ltd.“ Techpolymer MBX5
0, weight average particle size 50 μm ”

[0033]

The acrylic resin laminate having the appearance of crystal polished glass of the present invention is an acrylic resin laminate having both the transparent texture of crystal glass and the heavy texture of polished glass, and is subjected to thermoforming. However, it is an acrylic resin laminate in which the texture is not impaired and the disadvantages caused by adding a large amount of additives are prevented.

Accordingly, the acrylic resin laminate having the appearance of the crystal polished glass of the present invention can be used as a substitute for glass in securing safety and promoting weight reduction which will attract attention in the 21st century such as the aging society. It is suitably used for applications such as lighting fixture covers, various signs, and blind screens.

Claims (4)

[Claims] 1. The laminate has a total light transmittance of 70% or more, a haze of 80% or more, and a light diffusivity of 10% or more, and the structure of the laminate is an acrylic resin (A) 99 to 70% by weight. %
And the absolute value of the refractive index difference with the acrylic resin is 0.02
~ 0.2, and the weight average particle size is 1 ~ 100μm
Characterized in that an acrylic resin layer (a) containing 1 to 30% by weight of spherical fine particles (B) is laminated on one or both sides of a substrate layer (b) made of an acrylic resin. Acrylic resin laminate with the appearance of crystal polished glass. 2. The acrylic resin laminate having the appearance of crystal polished glass according to claim 1, wherein the spherical fine particles (B) are crosslinked siloxane resin fine particles and / or crosslinked styrene resin fine particles. . 3. The spherical fine particles further have an absolute value of a difference in refractive index from the acrylic resin (A) of less than 0.02,
Spherical acrylic crosslinked resin fine particles having a weight average particle diameter of at least twice the spherical fine particles (B) and 20 μm or more,
The acrylic resin laminate having the appearance of a crystal polished glass according to claim 1 or 2, wherein 1 to 20 parts by weight is blended with respect to the acrylic resin layer (a). 4. A lighting cover using an acrylic resin laminate having the appearance of the crystal polished glass according to claim 1, 2 or 3.