JP3297086B2 - Manufacturing method of resin molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin molded article having an irregular shape using active energy rays, and more particularly to a projection screen used as a screen of a projection television or a microfilm reader. And a method for manufacturing a Fresnel lens or a lenticular lens.

[0002]

2. Description of the Related Art As a method of manufacturing a sheet-like resin molded product having an uneven shape on the surface of a Fresnel lens, a lenticular lens, or the like, a method of injection molding a synthetic resin, a method of contacting a resin plate with a molding die, This is heated and pressurized to transfer the surface unevenness of the molding die to a press molding method, or an active energy ray-curable resin composition is injected into a molding die, and then irradiated with active energy rays to form the resin composition. Curing methods and the like are known.

[0003]

However, in the injection molding method, it is difficult to form a large-sized molded product.
It can only be used for molding relatively small sized moldings. In addition, in the press molding method, a long time is required for the heating and cooling cycle of the resin plate and the molding die. Therefore, a large number of molding dies are required for mass production of the resin molded product. Costs a lot of production equipment.

On the other hand, the method using the active energy ray-curable resin composition can shorten the molding time and improve the productivity. However, when injecting the resin composition into the mold, there are problems such as entrapment of bubbles and the like, and in order to solve this, separate defoaming treatment or slowly injecting The method had to be adopted, which was not enough for mass production.

Further, when the transparent base material and the active energy ray-curable resin are integrally molded, a low-viscosity composition is used in order to suppress the entrapment of bubbles during the injection of the active energy ray-curable resin composition as much as possible. Often used.
However, a low-viscosity composition has a large shrinkage ratio during polymerization, and the stress due to polymerization shrinkage may lower the adhesiveness to the base material or may not be able to sufficiently transfer the uneven shape of the mold.

As described in JP-A-1-192529 as a method for producing a lens sheet, a low-viscosity ultraviolet-curable resin liquid (first resin liquid) is applied to a lens mold, and then a comparison is made. A method has been proposed in which a highly viscous ultraviolet-curable resin liquid (second resin liquid) is injected, a transparent substrate is superimposed, irradiated with ultraviolet light, cured and demolded.
However, in such a method, if a raised portion is formed in the first resin liquid applied to the lens mold, the thickness remains as a lens sheet thickness unevenness even after the second resin liquid is injected and cured. This may cause deterioration of lens quality. Further, when the second resin liquid is injected, the first resin liquid moves while being pressed by the second resin liquid, and bubbles due to the shape of the lens shape are generated between both resin layers, There is a problem that such bubbles remain in the lens and cause a lens defect.

Therefore, an object of the present invention is to efficiently produce a resin molded product having an uneven shape on the surface, and to accurately transfer the shape of a molding die free of bubbles, and to reduce unevenness in thickness. There is no resin molded product.

[0008]

Means for Solving the Problems In view of the above-mentioned problems of the prior art, the present inventors have conducted intensive studies on a method of manufacturing a lens sheet using an active energy ray-curable resin composition. The invention has been reached. That is, the manufacturing method of the lens sheet of the present invention, the uneven shape
A first radiation-curable resin composition was spread to a mold having a lens pattern, 320-39 in the composition
An active energy ray having an integrated irradiation amount of 0 nm of 10 to 1000 mJ / cm ² is irradiated, and then a second active energy ray-curable resin composition is spread on the first active energy ray-curable resin composition. After laminating a transparent base material, a first active energy ray-curable resin composition from the transparent base material side
It is characterized in that irradiation morphism a large amount of the active energy ray than integrated irradiation dose irradiated to the object.

The resin molded article of the present invention is not particularly limited as long as it has an irregular shape on the surface, and the production method of the present invention can be applied. A resin molded product having a concave-convex shape having characteristics is exemplified. Above all, it is excellent in shape transferability of a mold and can produce a uniform resin molded product without thickness unevenness, so that it is suitable for producing a resin molded product used for optical applications such as a lens. In particular, since a large-sized molded product can be efficiently manufactured, it is most suitable for manufacturing a lens sheet such as a Fresnel lens or a lenticular lens used for a projection screen used as a screen of a projection television or a microfilm reader.

The mold used in the present invention has an appropriate uneven shape on the inner surface, and is preferably a planar mold in terms of usability, but is not particularly limited thereto. Various molds such as a mold, a glass mold, and a resin mold can be used. The thickness and material of the transparent substrate used in the present invention are not particularly limited. However, when used for a molded article for optical use such as a lens, the light transmittance due to coloring or turbidity is caused. Is not preferred. Examples of usable materials include plastics and glass, and specific examples include acrylic resins, polycarbonate resins, polyester resins, polystyrene resins, fluororesins, polyimide resins, and copolymers and polymer alloys of these resins. The thickness of the transparent substrate is preferably 3 mm or less from the viewpoint of the transmittance of the active energy ray and the handling property. In particular, when used in a lens sheet for a projection screen such as a Fresnel lens or a lenticular lens, the optical characteristics such as multiple images and iridescent spots are considered.
mm or less.

The active energy ray-curable resin composition used in the present invention includes polyhydric acrylates and / or polyhydric methacrylates (hereinafter referred to as polyhydric (meth) acrylates) in terms of handleability and curability. ), Monoacrylate and / or monomethacrylate (hereinafter, referred to as mono (meth) acrylate), and a photopolymerization initiator using active energy rays as a main component are preferable. Further, in the present invention, an active energy ray-curable resin composition (first resin composition) spreading on a molding die and an active energy ray-curable resin composition (second resin composition) injected thereon are used.
The first resin composition and the second resin composition may have the same composition or different compositions. Even in the case of the same composition, those having different physical properties such as viscosity can be used. Representative polyvalent (meth) acrylates include polyol poly (meth) acrylate, polyester poly (meth) acrylate, epoxy poly (meth) acrylate, urethane poly (meth) acrylate, and the like. These are used alone or as a mixture of two or more.

Examples of the mono (meth) acrylate include a mono (meth) acrylate of a monoalcohol and a mono (meth) acrylate of a polyol. In the latter case, the influence of a free hydroxyl group is given. However, when the metal mold is used, it is better not to use it in a large amount.
Also, since (meth) acrylic acid and its metal salt have high polarity, it is better not to use a large amount when using a metal type. The first resin composition preferably has a low viscosity and does not involve air bubbles, and preferably has a methacrylate component as a main component. In addition, as described later, the curability in the presence of air is poor, and the adhesion to the second resin composition can be improved, which is preferable.

The active energy ray applied to the first resin composition in the present invention has an irradiation amount of 320 to 390 nm.
It requires der that an accumulated irradiation amount of a 10~1000mJ / cm ² is, to a range of 180~500mJ / cm ²
Preferably . This means that the irradiation dose is 10 mJ / cm ²
If the amount is less than the above, the curing reaction of the resin composition does not proceed, which causes uneven thickness and bubbles due to injection of the second resin composition. Conversely, if the irradiation amount exceeds 1000 mJ / cm ² , the adhesiveness to the second resin composition layer may be reduced, or coloring may be caused by irradiation with active energy rays after the injection of the second resin composition. That's why. By irradiating the active energy ray with the irradiation amount in this range, only the inner surface of the first resin composition can be cured or semi-cured, so that it has excellent adhesion to the second resin composition,
The interface can also be made optically uniform.

Further, the irradiation of the first resin composition of the present invention with an active energy ray is carried out through a material which absorbs or reflects light having a wavelength of 300 nm or less through an air layer on the composition. Irradiation is preferably performed. This is because if there is a resin having a wavelength of 300 nm or less, a resin having relatively poor curability may be cured, and by absorbing or reflecting the resin having the wavelength, only the inner surface of the resin composition is cured or This is because it can be easily controlled to be in a semi-cured state. In addition, by interposing such a material, it is possible to suppress the waving of the resin composition surface due to cooling air in order to cool the active energy ray irradiation lamp, and to make the interface with the second resin composition layer uniform. Something you can do. 300nm like this
As a material that absorbs or reflects the following wavelengths, a wavelength selection plate using an optical thin film, a general glass plate, an acrylic resin,
Resin plates such as polycarbonate resin and polyester resin,
Sheets or films can be used.

After irradiating the first resin composition with an active energy ray, the second resin composition is spread thereon. Next, the transparent substrates are overlapped and brought into close contact with each other, and irradiated with active energy rays again through the transparent substrates. In this case, the second
Since the resin composition and the transparent base material are in close contact with each other, the curing of the resin composition is not inhibited by the presence of air, and thus a sufficiently cured molded article can be obtained.

[0016]

The present invention will be specifically described below with reference to examples. Example 1 800 mm × 600 mm stuck on a 3 mm thick iron plate
Ethylene oxide-modified bisphenol A dimethacrylate (Fancryl FA-Hitachi, manufactured by Hitachi Chemical Co., Ltd.)
321M) 45 parts by weight, ethylene oxide-modified bisphenol A diacrylate (NK ester A-BPE-4 manufactured by Shin-Nakamura Chemical Co., Ltd.) 25 parts by weight, tetrahydrofurfuryl acrylate (Sartomer 285 manufactured by Sartomer) 30
Parts by weight, 2-hydroxy-2-methyl-1-phenylpropan-1-one (Darocur 11 manufactured by Merck Japan Ltd.)
73) The first resin composition mixed with 3 parts by weight was spread. Then, 4 mm thick through a 15 mm spacer
Is placed on a soda glass plate, and ultraviolet rays are irradiated using a high-pressure mercury lamp at a cumulative irradiation dose of 320 to 390 nm for 500 m.
J / cm ^{2 was} irradiated. The surface of the first resin composition was cured with tackiness remaining.

After spreading the second resin composition comprising the same composition on the first resin composition, a thickness of 2 mm
Of methacrylic resin plates were superimposed. Excess resin composition is removed by a pressure roll, and ultraviolet rays are irradiated using a high-pressure mercury lamp at an integrated ultraviolet irradiation amount of 320 to 390 nm to 1100.
Irradiation at mJ / cm ² was performed. After that, remove from the lens mold,
A Fresnel lens integrated with a transparent substrate was obtained. The obtained Fresnel lens accurately transferred the shape of the lens mold, and had a shape as designed. In addition, the transparent substrate, the first
Both the resin layer and the second resin layer were excellent in adhesion, had no defects such as bubbles, and were uniform without thickness unevenness.

Example 2 The same first resin composition as in Example 1 was spread on the same lens mold as in Example 1. Then, a methacrylic resin plate having a thickness of 2 mm was placed via a 10 mm spacer, and ultraviolet rays were irradiated using a high-pressure mercury lamp at a cumulative irradiation dose of 320 to 390 nm at 200 mJ / cm ² . The surface of the first resin composition was cured with tackiness remaining.
After spreading the second resin composition comprising the same composition on the first resin composition, a 250 μm-thick easily-adhesive polyester film (Lumirror T type AC- (X) manufactured by Panac Co., Ltd.) ) Were superimposed. Excess resin composition is removed by a pressure roll, and ultraviolet rays are irradiated using a high-pressure mercury lamp at a total irradiation amount of 320 to 390 nm of 1100 m.
J / cm ^{2 was} irradiated. Thereafter, the Fresnel lens was released from the lens mold and integrated with the transparent substrate. The obtained Fresnel lens accurately transferred the shape of the lens mold, and had a shape as designed. Further, the transparent substrate, the first resin layer and the second resin layer were all excellent in adhesion, free from defects such as bubbles, and uniform without thickness unevenness.

Example 3 1180 mm × 880 m stuck on a 3 mm thick iron plate
An ethylene oxide-modified bisphenol A dimethacrylate (Fancryl FA manufactured by Hitachi Chemical Co., Ltd.)
-321M) 47 parts by weight, phenixiethyl acrylate (Viscoat # 192 manufactured by Osaka Organic Chemicals) 28 parts by weight, bifunctional acrylate (Nippon Kayaku Co., Ltd., Kayarad R)
-604) 25 parts by weight, 2-hydroxy-2-methyl-
The first resin composition mixed with 2 parts by weight of 1-phenylpropan-1-one (Darocur 1173 manufactured by Merck Japan) was spread. Then, using a high-pressure mercury lamp, the ultraviolet rays were irradiated at an integrated irradiation amount of 320 to 390 nm of 180 mJ /
cm ^{2 was} irradiated. The surface of the first resin composition was cured with tackiness remaining.

After spreading the second resin composition comprising the same composition on the first resin composition, a thickness of 500
A μm polycarbonate film (dialite manufactured by Mitsubishi Rayon Co., Ltd.) was overlaid. Excess resin composition is eliminated by a pressure roll, and ultraviolet rays are irradiated using a high-pressure mercury lamp.
900 mJ / c with integrated UV irradiation of 20-390 nm
m ² irradiation. Thereafter, the Fresnel lens was released from the lens mold and integrated with the transparent substrate. The obtained Fresnel lens accurately transferred the shape of the lens mold, and had a shape as designed. Further, the transparent substrate, the first resin layer and the second resin layer were all excellent in adhesion, free from defects such as bubbles, and uniform without thickness unevenness.

Example 4 1180 mm × 880 m stuck on a 3 mm thick iron plate
An ethylene oxide-modified bisphenol A dimethacrylate (Fancryl FA manufactured by Hitachi Chemical Co., Ltd.)
-321M) 47 parts by weight, phenoxyethyl acrylate (Viscoat # 192 manufactured by Osaka Organic Chemicals Co., Ltd.) 31 parts by weight, 1,6-hexanediol dimethacrylate (Mitsubishi Rayon Co., Ltd. acrylic ester HX) 22 parts by weight, 2-
Hydroxy-2-methyl-1-phenylpropane-1-
On (Darocure 1173 manufactured by Merck Japan) 1.5
The first resin composition mixed with parts by weight was spread. Next, ultraviolet light was irradiated at 180 mJ / cm ² at a cumulative irradiation dose of 320 to 390 nm using a high-pressure mercury lamp. First
The surface of the resin composition was cured with tackiness remaining.

After spreading the second resin composition comprising the same composition on the first resin composition,
A μm polycarbonate film (dialite manufactured by Mitsubishi Rayon Co., Ltd.) was overlaid. Excess resin composition is eliminated by a pressure roll, and ultraviolet rays are irradiated using a high-pressure mercury lamp.
900 mJ / c with integrated UV irradiation of 20-390 nm
m ² irradiation. Thereafter, the Fresnel lens was released from the lens mold and integrated with the transparent substrate. The obtained Fresnel lens accurately transferred the shape of the lens mold, and had a shape as designed. Further, the transparent substrate, the first resin layer and the second resin layer were all excellent in adhesion, free from defects such as bubbles, and uniform without thickness unevenness.

Example 5 1180 mm × 880 m stuck on a 3 mm thick iron plate
An ethylene oxide-modified bisphenol A dimethacrylate (Fancryl FA manufactured by Hitachi Chemical Co., Ltd.)
-321M) 47 parts by weight, phenoxyethyl acrylate (Viscoat # 192 manufactured by Osaka Organic Chemicals Co., Ltd.) 31 parts by weight, 1,6-hexanediol dimethacrylate (Mitsubishi Rayon Co., Ltd. acrylic ester HX) 22 parts by weight, 2-
Hydroxy-2-methyl-1-phenylpropane-1-
On (Darocure 1173 manufactured by Merck Japan) 1.5
The first resin composition mixed with parts by weight was spread. Next, ultraviolet light was irradiated at 180 mJ / cm ² at a cumulative irradiation dose of 320 to 390 nm using a high-pressure mercury lamp. First
The surface of the resin composition was cured with tackiness remaining.

On the first resin composition, 47 parts by weight of ethylene oxide-modified bisphenol A dimethacrylate (Fancryl FA-321M manufactured by Hitachi Chemical Co., Ltd.) and phenoxyethyl acrylate (Biscoat # manufactured by Osaka Organic Chemical Co., Ltd.)
192) 28 parts by weight, 25 parts by weight of bifunctional acrylate (Kayarad R-604, manufactured by Nippon Kayaku Co., Ltd.), 2-hydroxy-2-methyl-1-phenylpropan-1-one (Darocur 1173, manufactured by Merck Japan Ltd.) 2 The second resin composition mixed with parts by weight was spread. After that, thickness 500
A μm polycarbonate film (dialite manufactured by Mitsubishi Rayon Co., Ltd.) was overlaid. Excess resin composition is eliminated by a pressure roll, and ultraviolet rays are irradiated using a high-pressure mercury lamp.
1000 mJ / with integrated UV irradiation of 20 to 390 nm
cm ^{2 was} irradiated. Thereafter, the Fresnel lens was released from the lens mold and integrated with the transparent substrate. The resulting Fresnel lens accurately transfers the lens shape,
The shape was as designed. Further, the transparent substrate, the first resin layer and the second resin layer were all excellent in adhesion, free from defects such as bubbles, and uniform without thickness unevenness.

Comparative Example 1 The same first resin composition as in Example 1 was spread on the same molding die as in Example 1, and a 250 μm-thick easily-adhesive polyester film (Lumirror T type AC manufactured by Panac Co., Ltd.) was used. −
(X)). Excess resin composition is removed by a pressure roll, and ultraviolet rays are irradiated using a high-pressure mercury lamp.
1100mJ / cm with integrated UV irradiation of ~ 390nm
^Two irradiations were performed. Thereafter, the mold was released from the mold to obtain a Fresnel lens integrated with the transparent substrate. The obtained Fresnel lens had poor adhesion to the transparent substrate due to stress caused by polymerization shrinkage of the ultraviolet curable resin composition, and the cured resin was adhered to the stamper of the molding die. In addition, the shape shrank more than the shape of the mold, and the shape deviated from the design.

Comparative Example 2 The same first resin composition as in Example 1 was spread on the same mold as in Example 1. Next, using a high-pressure mercury lamp, ultraviolet rays were irradiated at an integrated ultraviolet irradiation amount of 320 to 390 nm for 1100.
Irradiation at mJ / cm ² was performed. The surface of the first resin composition was completely cured without tackiness. After spreading the second resin composition composed of the same composition on the first resin composition, a 250 μm-thick easily-adhesive polyester film (Lumirror T type AC-Panac)
(X)). Excess resin composition is removed by a pressure roll, and ultraviolet rays are irradiated using a high-pressure mercury lamp.
1100mJ / cm with integrated UV irradiation of ~ 390nm
^Two irradiations were performed. Thereafter, the mold was released from the mold to obtain a Fresnel lens integrated with the transparent substrate. The obtained Fresnel lens accurately transferred the shape of the mold, and had a shape as designed, but had poor adhesion between the first resin layer and the second resin layer, and was easy at the interface. Has peeled off.

Comparative Example 3 The same first resin composition as in Example 1 was spread on the same mold as in Example 1. Then, after spreading a second resin composition of the same composition as the first resin composition on the first resin composition, a 250 μm-thick easily-adhesive polyester film (Lumirror T type manufactured by Panac Co., Ltd.) AC- (X)). Excess resin composition is eliminated by a pressure roll, and ultraviolet rays are irradiated at 320 to 390 n using a high-pressure mercury lamp.
1100 mJ / cm ^{2 was} applied at an integrated ultraviolet irradiation dose of m. Thereafter, the mold was released from the mold to obtain a Fresnel lens integrated with the transparent substrate. The obtained Fresnel lens is
The shape of the mold was accurately transferred, and the shape was as designed, but it contained bubbles inside the Fresnel lens,
It had lens defects.

[0028]

Since the present invention has the construction as described in detail above, it is possible to efficiently produce a resin molded product having an uneven shape on the surface and to accurately transfer the shape of a molding die. It is a resin molded product suitable for optical applications such as a Fresnel lens or a lenticular lens used for a projection screen etc. is there.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshinobu Shiraishi 4-160 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi Examiner, Product Development Laboratory, Mitsubishi Rayon Co., Ltd. Yasuhide Nomura (56) References JP-A-58-30755 (JP, A) JP-A-60-56544 (JP, A) JP-A-1-7001 (JP, A) JP-A-4-50805 (JP, A) JP-A-1-86102 (JP, A) Kaihei 1-192530 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 39/10-39/12 B29C 39/22-39/24 B29D 11/00 G02B 3/00 -3/08 G03B 21/60-21/62

Claims (3)

(57) [Claims] 1. A first active energy ray-curable resin composition is spread on a mold having an irregular lens pattern , and the integrated irradiation amount of 320 to 390 nm is 10
Irradiate active energy rays of ~ 1000 mJ / cm ² ,
Next, after spreading the second active energy ray-curable resin composition on the first active energy ray-curable resin composition and superimposing a transparent substrate, the first active energy ray-curable resin composition is firstly activated from the transparent substrate side .
From the integrated irradiation amount irradiated to the energy ray-curable resin composition
A method for producing a lens sheet , comprising irradiating a large amount of active energy rays. 2. A first active energy ray-curable resin composition
320-390 nm of active energy rays for irradiating an object
180-500mJ / cm ² That is
The method for producing a lens sheet according to claim 1, wherein: 3. The process for producing a lens sheet according to claim 1 or 2, characterized in that a thickness of 3mm or less of the transparent substrate.