JPS6244023B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing a photochromic molded article,
More specifically, the present invention relates to a method for producing a photochromic molded article from a composition containing a photochromic glass powder, a synthetic resin, and a coupling agent as main components.

Conventional technology and its problems Photochromic glass itself is well known and is used, for example, as lenses for eyeglasses, and is colorless and transparent indoors, but changes to a dark black to brown color outdoors. Functions as sunglasses. That is, photochromic glass is colorless indoors, but turns black or brown when outdoors or under sunlight, and returns to colorless when returned indoors. This characteristic occurs because the silver halide contained in the glass decomposes into silver and halogen when exposed to ultraviolet rays, turning the color black or brown due to the silver, and when not irradiated with ultraviolet rays, the silver and halogen react again. It is based on the fact that it becomes silver halide and becomes colorless.

The present inventor believes that if the characteristics of photochromic glass can be imparted to compositions mainly made of synthetic resin and molded products obtained from the same, the characteristics can be utilized in a wide range of fields. I thought it was a thing.
That is, (i) it has a lower molding temperature and is easier to mold than glass, (ii) it has better mechanical strength than glass, and (iii) it can be molded into any shape without polishing. (iv) Can be used as a paint, (v) Can be formed into a thin film, etc. If a composition that has both the properties of a synthetic resin and photochromism can be obtained, the fields of its use will significantly increase. That's what I do. However, according to subsequent research by the present inventor, when silver halide is simply added to a transparent synthetic resin, or when a transparent synthetic resin and a photochromic glass powder are simply mixed, the type of synthetic resin changes. Regardless of the method, it was found that almost no photochromism was expressed in the molded article.

Means for Solving the Problems As a result of further research, the inventor of the present invention determined that a specific glass pre-containing silver halide was made into granules with a constant particle size, and the granules were made into granules with a certain particle size so as to prevent air from being mixed in. It has been found that when a composition obtained by mixing a specific resin with a specific resin is molded and the molded product is compressed, extremely excellent photochromism is exhibited.

That is, the present invention provides (i) (a) 100 parts by weight of a synthetic resin with a transmittance of 40% or more, and (b) a particle size of 37 cm containing silver halide.
10 to 70 parts by weight of ~350 μm photochromic glass granules and (c) 0.015 to 8 parts per gram of photochromic glass granules
mg of a coupling agent and (ii) the difference in refractive index between the synthetic resin and the photochromic glass is ±0.005 or less, mixed under a reduced pressure of at least 5×10 ⁻¹ Torr, and then molded; The present invention provides a method for producing a photochromic molded article, which is characterized by compressing the molded article to make its surface smooth.

As the silver halide used in the present invention, those conventionally used in photochromic glasses are widely used, such as silver chloride, silver bromide, silver iodide, etc., among others. Silver chloride is preferred, but two or more types may be used in combination. As granular glass,
Silicate glass, borosilicate glass, borosilicate glass, and phosphate glass are used, and two or more of these glasses containing silver halide may be used as a mixture in powder form. Moreover, any method of adding silver halide to the glass may be used as long as the silver halide can be uniformly dispersed in the glass. Specific examples of the silver halide-containing glass used in the present invention include those disclosed in Japanese Patent Publication No. 40-11944 (US Pat. No. 3,208,860) and Japanese Patent Publication No. 56-9465. The silver halide content in glass is usually 0.05 to 1.5 of the glass weight.
% (as Ag), therefore, the halogen is present in an equivalent amount or more relative to Ag. The particle size of silver halide-containing glass granules is 37-350
It is about μm. If the particle size of the glass powder is too small, even if the refractive index of the synthetic resin and glass are similar, the specific surface area of the glass particles will significantly increase, and the diffused reflection by the glass particles will become intense and the transmittance will decrease. decreases, and photochromism is not fully expressed. If the particle size of the glass powder is too large, the specific surface area hardly decreases, so no improvement in transmittance is observed, processability decreases, and it is difficult to form a thin film, so the practical value is greatly reduced.

In the present invention, the glass particles and the synthetic resin are chemically bonded by surface-treating the glass particles as described above with at least one type of silane coupling agent or by adding this to the composition. Avoid forming an air layer at the interface. That is, since glass particles and resin inherently have low affinity, when simply mixing the two, an air layer is likely to be formed at the interface between the two. In this case, since the refractive index of air is the minimum (absolute refractive index 1.000293), the difference in refractive index between the resin and the air layer and the difference in the refractive index between the glass particles and the air layer become maximum, causing diffuse reflection. , lowering the transmittance and significantly deteriorating the photochromic performance of the molded article. In addition, when an air layer exists, the air layer expands and contracts repeatedly due to temperature changes, increasing separation at the interface between glass particles and synthetic resin, increasing diffuse reflection, and reducing transmittance and light. Tautomeric performance deteriorates over time. If a coupling agent is used during the preparation of the composition under reduced pressure, air layers are better excluded from the interface between the glass particles and the synthetic resin, so these problems are even more severe. Reduced. Examples of the silane coupling agent include δ-glyditoxymethyldimethoxysilane, N-β-aminoethyl-δ-aminopropylmethyldimethoxysilane, δ-chloropropylmethyldimethoxysilane, δ-methicaptopropyhelmethyldimethoxysilane, δ-aminopropylmethyldiethoxysilane, N-cyclohexyl-
δ-aminopropyltrimethoxysilane, N-benzyl-δ-aminopropyltrimethoxysilane, N-β-(N-vinylbenzylamino)ethyl-δ-aminopropyltrimethoxysilane, N
-Vinylbenzyl-δ-aminopropyltriethoxysilane, δ-ureidopropyltriethoxysilane, vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-
Methacryloxypropyltrimethoxysilane, β
-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glyditoxypropylmethyldiethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxy silane,
N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriliethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane Examples include methoxysilane. The amount of coupling agent used for glass particles is about 0.015 to 8 mg per gram of glass. If the amount of the coupling agent used is excessive, the thickness of the coupling agent attached to the surface of the glass particles becomes large, and the influence of the refractive index of the coupling agent layer itself becomes large, which is not preferable. As a method for applying the coupling agent, for example, the glass particles may be surface-treated with a silane coupling agent in advance, or the silane coupling agent may be added during kneading of the composition.

Known additives can be added to the silver halide-containing glass used in the present invention, if necessary. Examples of such known additives include photosensitizers such as copper, cadmium, and sulfur, and refractive index enhancers such as barium and sodium.

The transparent synthetic resin with a transmittance of about 70% or more and the translucent synthetic resin with a transmittance of about 40 to 70% used in the present invention have a refractive index close to the refractive index of the glass. The difference in refractive index (N ²⁰ _D ) between the synthetic resin and glass is within ±0.005. One of the requirements for imparting excellent photochromism to the composition of the present invention is to keep it within ±0.005. Examples of the synthetic resin used in the present invention include the following.

Acrylic resin...Polyacrylic acid, polyacrylic ester, polymethyl methacrylate, methacrylic acid-styrene copolymer, methacrylic acid-α-
Methylstyrene copolymer, etc.

Cellulose resin: ethyl cellulose plastic, acetyl cellulose plastic, acetyl butyl cellulose plastic, etc.

Epoxy resins such as phenol novolak epoxy resin, cycloaliphatic epoxy resin, ortho-cresol novolak resin, etc.

Fluorine-containing plastics: polychlorotrifluoroethylene, tetrafluoroethylene-fluoropropylene copolymer, polyvinylidene fluoride, ethylene-chlorotrifluoroethylene copolymer, etc.

Olefin resins: ionomer, polyalomer, polybutylene, polyethylene, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, polypropylene, polymethylpentene, propylene-vinyl chloride copolymer, etc.

Polyamide...Polyamide 6-6, polyamide 6, polyamide 6-12, polyamide 6-10, polyamide 11, polyamide 12, etc.

Phenol resin...phenol resin, phenol-formaldehyde resin, etc.

Carbonate resin…polycarbonate,
ABS - Porelicarbonate, allyl diglycol carbonate, etc.

Polyester...Unsaturated polyester, alkyd resin, etc.

Styrene resin: polystyrene, styrene-acronitrile copolymer, styrene-butadiene copolymer, etc.

Vinyl resin…polyvinyl chloride, vinyl chloride
Vinyl acetate copolymer, polyvinylidene chloride, polyvinyl formal, polyvinyl butyral, etc.

In the present invention, the following known additives for resins can be added to the synthetic resin as required.

Colorants: Colorants such as red, yellow, orange, green, and blue (green and blue are limited to those with weak hiding power) easily absorb ultraviolet rays, and the amount of synthetic resin
Photochromism is improved by using it in a range of about 0.001 to 5%. Such coloring agents include Quinacridone Maroon Medium Red, BON Maroon Light Red, Pigment Scarlet Blue Yellow, Cadmium Sulfide Yellow,
Examples include nickel azo green yellow, phthalocyanine green, ultramarine blue, phthalocyanine blue, industhrene blue, and putoma violet medium red. Stabilizers...For example, when chlorine-containing resins are irradiated with ultraviolet rays, they undergo dehydrochlorination to form a polyene structure, which is colored and reduces the photochromic effect. Therefore, it is preferable to add a stabilizer that does not impair transparency. Examples of such stabilizers include dialkyltin laurate, dialkyltin maleate, zinc stearate, barium stearate, calcium stearate, epoxidized fatty oil, phosphite, dialkyltin mercaptide, etc. If necessary, one or more of these may be used in an amount of about 0.5 to 10% of the weight of the chlorine-containing resin.

Ultraviolet absorber: By using an ultraviolet absorber, good photochromism can be achieved even when the transmittance of the composition is relatively low. Specifically, salicylic acid esters such as phenyl salicylate, 2
-benzotriazoles such as (2'-hydroxy-5-methylphenyl)benzotriazole, 2-
Hydroxybenzophenone, 2-hydroxy-4
-Methoxybenzophenone, 2-hydroxy-4
-Hydroxybenzophenones such as octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, alkyl-2-cyano-
Examples include acrylonitrile substituted products such as 3,3'-diphenyl acrylate. These ultraviolet absorbers are used in an amount of about 0.01 to 0.6% of the weight of the resin, if necessary.

Defoaming agent: has the effect of promoting the removal of air bubbles that may be mixed in when mixing silver halide-containing silver halide and synthetic resin. Typical examples include dimethylsiloxane, a silicone defoamer commercially available under the trade name "Antifoam 165", and glycerin. Add a defoaming agent to the weight of the resin, if necessary.
It is used in an amount of about 0.1 to 2%.

Other Additives: Viscosity-lowering agents such as phosphite esters can be used to reduce the viscosity of the resin, thereby making it easier to knead with glass particles and process the resulting composition. in this case,
The lower viscosity of the resin facilitates defoaming during kneading with glass particles, which removes the air layer at the interface between the resin and glass particles, prevents diffused reflection due to the presence of the air layer, and improves transmittance. Therefore, the effect of improving photochromism is also achieved. Furthermore, in order to prevent deterioration and alteration of the synthetic resin, an antioxidant can be used. Such antioxidants include
Alkylphenols such as 2,6-di-t-butyl-p-cresol, 2,2'-methylenebis(4
-methyl-6-t-butylphenol), alkylene bisphenols such as 2,2'-thiobis(4
-methyl-6-t-butyl-m-cresol) and other alkylphenol thioethers.

Furthermore, when mixing with glass particles, it is also possible to add a known plasticizer, solvent, etc. to the synthetic resin to facilitate mixing.

The blending ratio of the synthetic resin and silver halide-containing glass particles in the present invention is usually about 10 to 70 parts by weight of the latter to 100 parts by weight of the former, preferably 100 parts by weight of the former.
The latter is preferably about 30 to 50 parts by weight.

The composition used in the present invention is obtained by mixing silver halide-containing glass particles and a synthetic resin under reduced pressure either as they are or with a solvent added thereto in the presence of a silane coupling agent.

When mixing photochromic glass powder and synthetic resin, if you simply mix them, air will be mixed in and an air layer will be formed at the interface between the glass powder and the synthetic resin, and this air layer will cause diffused reflection. This may reduce the transmittance of the composition and inhibit photochromism. Therefore, in the present invention, the composition is prepared under reduced pressure of at least 5×10 ^-1 Torr to prevent air inclusion.

Next, the obtained composition is compressed while being molded into a desired shape or after being molded. In other words, a molded article containing photochromic glass powder shrinks after being heated and molded, so that some of the glass particles are exposed on the surface, as shown in Figure 1a, and this causes diffuse reflection on the surface. As a result, the transmittance decreases. When such a molded product is compressed during the molding process or after molding, the glass particles exposed on the surface are pushed into the molded product, and the surface becomes smooth as shown in Figure 1b, making it easier to form the molded product. The transmittance is
Greatly improved.

Although it cannot be said that the reason why the molded article according to the present invention specifically exhibits extremely excellent photochromism has not yet been completely elucidated, it is presumed to be as follows. That is, halogen halide has the property of being unstable and easily reacting with organic matter. Therefore, when silver halide is contained in a synthetic resin, the halogen ions generated and separated during ultraviolet irradiation react with the organic synthetic resin and become stable, so even when the ultraviolet irradiation is stopped, silver ions are generated again. cannot react with silver halide to form silver halide. Therefore, reversible changes resulting in photochromism cannot occur. In contrast, in the molded article of the present invention, silver halide is incorporated into the synthetic resin while being included in glass particles, so the halide ions generated during light irradiation are not in contact with the synthetic resin. , cannot react with this. Therefore, since the halogen ion is unstable but exists alone, when the light irradiation is stopped, it reacts with silver again to form silver halide, and the resin becomes transparent.

Furthermore, the particle size of the photochromic glass particles was kept within a specific range, a specific amount of coupling agent was used, and the difference in refractive index between the synthetic resin and the photochromic glass was kept below a certain value. This, together with the requirement that the surface of the molded product be smooth, has made it possible to obtain a molded product with a high degree of photochromism.

Effects of the Invention The product of the present invention can be usefully used in the following various applications.

(1) When a coating is prepared by adding the composition to a suitable vehicle or a suitable solvent, a photochromic coating can be formed.

(2) By forming the composition into a sheet according to conventional methods, it can be used as an alternative to window glasses and sun visors, reversible recording materials, and exposure meters whose transmittance automatically changes depending on the intensity of ultraviolet rays. It is useful as a camera filter, etc.

(3) By forming the composition into a bottle or container,
It is advantageously used as a decorative item that changes color in response to changes in light rays, and as a protective container for substances that are easily affected by ultraviolet rays.

(4) By molding the composition of the present invention as it is into the face and limbs of a doll, or by applying it to the face and limbs of a doll, a tanned doll with an excellent decorative effect can be obtained.

(5) It is also useful as a recording sheet for holographic recording.

Examples Examples and comparative examples are shown below to further clarify the characteristics of the present invention.

Examples 1 to 2 (a) Vinyl chloride resin (trademark "Zeon 37J", manufactured by Nippon Zeon Co., Ltd., _{transmittance} 50%, ^N20D = 1.540)
40g, vinyl chloride resin (trademark “Zeon
103ZX”, manufactured by Nippon Zeon Co. _, Ltd., transmittance 50%, ^N20D
= 1.540) 60g, dioctyl phthalate 80g, Ba
-Zn-Sn stabilizer (trademark "KR-69A-10",
Kyodo Yakuhin Co., Ltd.) 2g, and silane coupling agent (trademark "KBM403", Shin-Etsu Chemical Co., Ltd.)
Photochromic glass granules surface-treated with 0.01g (trademark "React Light Rapide GREY90")
(FRX2), manufactured by Chang Spilkington _, UK, aluminophosphate glass, particle size 37-88μm, ^N20D
= 1.543) was added and kneaded in a high vacuum of 5 x 10 ^-3 Torr while defoaming, and heated at 180°C for 5 minutes between glass plates to form a 1.
It was formed into a sheet of mm and was cooled as it was. The change in transmittance of the thus obtained sheet a is as shown as curve A in FIG.

(b) A benzophenone ultraviolet absorber (trademark "VIOSORB-130", manufactured by Kyodo Yakuhin Co., Ltd.) is added to the above (a).
The thickness is 1 in the same manner as in (a) except that 0.3g is added.
A sheet of mm was obtained. The change in transmittance of sheet (b) is shown as curve B in FIG.

It is clear that the use of UV absorbers improves the photochromic performance.

In addition, the measurement of transmittance in this specification was performed as follows. The above sheet is held upright at a temperature of 20℃, and while irradiating xenon light (150W) at a distance of 160mm diagonally in front of the Diagonal 45 symmetrical to the incident direction of light
The change in transmittance of the sheet at 500 nm was measured by irradiating light with a wavelength of 500 nm or more from a direction of 500 nm.

Example 3 Methyl methacrylate-styrene copolymer (“Refractive Index Designated Pellet TE-104”, Mitsubishi Rayon Co., Ltd.)
Co., Ltd.) and 100 parts by weight of photochromic glass particles (trademark "Super Photo Gray", borosilicate glass, particle size 37~ 88 μm, manufactured by Corning Glass Co., USA, 10 parts by weight of N ²⁰ _D = 1.523) was added and uniformly kneaded under reduced pressure to obtain a composition of the present invention. This composition was injection molded at 250°C to form a sheet with a thickness of 3 mm, which was then compressed under heat to a thickness of 1.5 mm to make the surface smooth.

The transmittance of the obtained sheet in the wavelength range of 340 nm to 700 nm is shown as curve A in FIG.

Figure 3 shows the transmittance of a 1.5 mm thick sheet obtained by injection molding only the methyl methacrylate-styrene copolymer (refractive index N ²⁰ _D = 1.524) in the same manner as above and then compressing it. It is also shown as curve B.

As is clear from FIG. 3, in the wavelength range of about 500 nm or more, the transmittance of the sheet made of the composition of the present invention is not much different from the transmittance of a sheet made only of resin.

Comparative Example 1 15 parts by weight of silver chloride-containing photochromic aluminophosphate glass particles with a particle size of 44 to 88 μm and methyl methacrylate-styrene copolymer (trademark “Acrypet”)
M361 000XA Clear”, manufactured by Mitsubishi Rayon Co., Ltd., N ²⁰ _D
= 1.523) and 100 parts by weight were uniformly mixed at 250°C for 5 minutes under a reduced pressure of 5 × 10 ^-2 Torr, and then the mixture was
The molded product was press-molded at a pressure of 1000 Kg/cm ² to obtain a 3 mm thick molded product, which was then compressed at 250° C. to obtain a 1 mm thick test piece with a smooth surface. Six types of test pieces were created using six types of aluminophosphate glasses with different refractive indexes.

The curves in Figure 4 are for methyl methacrylate-styrene copolymer (N ²⁰ _D = 1.523) and six types of aluminophosphate glasses (N ²⁰ _D = 1.523, 1.522, 1.518,
1.511, 1.505, and 1.501) is plotted on the horizontal axis, and the drop rate of each test piece is plotted on the vertical axis.

As is clear from the curve in FIG. 4, when the refractive index of the photochromic glass and methyl methacrylate are equal, the transmittance of the test piece reaches about 85%. As the difference in refractive index between the two increases, the transmittance of the test piece gradually decreases, and when the difference in refractive index exceeds 0.005, the transmittance of the test piece decreases rapidly.

Example 4 Photochromic aluminophosphate glass particles similar to those used in Comparative Example 1 were mixed with a vinyltrimethoxysilane capric agent (trademark "KBM1003", manufactured by Shin-Etsu Chemical Co., Ltd., the amount used was based on the weight of the glass). 0.5%), 15 parts by weight of the glass granules and 100 parts by weight of the same methyl methacrylate-styrene copolymer as used in Comparative Example 1 were mixed under the same conditions as in Comparative Example 1. The sample was molded and compressed to obtain a test piece with a thickness of 1 mm and a smooth surface.

The relationship between the difference in refractive index between the copolymer and glass and the transmittance of each test piece is shown as a curve in FIG.

The curve in FIG. 4 shows almost the same tendency as the curve, but by surface-treating the glass particles with a silane coupling agent, the decrease in transmittance of the test piece is smaller. This clearly shows that better optical effects can be obtained.

Comparative example 2 Comparative example 1 except that mixing was performed without reducing pressure
Six types of test pieces with smooth surfaces were prepared in the same manner as above.

FIG. 4 shows the relationship between the difference in refractive index between the copolymer and glass used and the transmittance of each test piece as a curve.

From the curve in Figure 4, it can be seen that even if the difference in refractive index between the copolymer and the glass is 0.02 or less, if a silane capricant is not used and the composition is not mixed under reduced pressure during production. , the transmittance of the test piece becomes extremely low, so it is clear that it cannot be used.

Comparative Example 3 15 parts by weight of photochromic borosilicate glass particles containing silver chloride with a particle size of 44 to 88 μm, allyl diglycol carbonate monomer (trademark "CR-39", manufactured by PG Industries, Inc., ^N20D as a polymer ₎ = 1.499) and 3 parts by weight of diisopropyl peroxydicarbonate (hereinafter referred to as IPP) as a polymerization initiator were mixed with a vibrator under reduced pressure of 5 x 10 ¹³ torr. Heating of the mixture is started with the glass particles dispersed in the monomer by vibration,
The temperature was gradually raised to 60°C over 9 hours to form a gel. When the polymerization progressed and sedimentation of glass particles was no longer observed, the pressure inside the reactor was brought to normal pressure. The thus obtained gel was placed between two glass plates with a spacing of about 1 mm and heated to 90° C. for 6 hours to prepare a test piece material. Then allyl diglycol carbonate monomer as above
A mixture consisting of 100 parts by weight and 3 parts by weight of IPP was applied to the surface of the above test piece material, and then heated again at 60°C between glass plates to obtain a test piece with a thickness of 1 mm and a smooth surface. Four types of test pieces were created by using four types of borosilicate glass particles having different refractive indexes.

The curves in Figure 5 cross the refractive index difference between an allyl diglycol carbonate polymer (N ²⁰ _D = 1.499) and four borosilicate glasses (N ²⁰ _D = 1.500, 1.505, 1.514, and 1.523). The relationship is shown when the axis is taken as the vertical axis and the drop rate of each test piece is taken as the vertical axis.

As in Comparative Example 1, when the difference in refractive index between the photochromic glass and the resin exceeds 0.005, the transmittance of the test piece decreases rapidly.

Example 5 Photochromic borosilicate glass particles similar to those used in Comparative Example 3 were previously surface treated with a vinyltrimethoxysilane coupling agent similar to that used in Example 4. The amount of coupling agent used was approximately 0.1% of the weight of the glass granules. Next, in the same manner as in Comparative Example 3 except that the surface-treated glass granules were used, four types of test specimens each having a thickness of 1 mm and a smooth surface were obtained.

The relationship between the difference in refractive index between the polymer and glass used and the transmittance of each test piece is shown as curve V in FIG.

Curve V in FIG. 5 clearly shows that the use of a silane coupling agent results in a lower decrease in transmittance and therefore a much better optical effect than in Comparative Example 3.

Comparative Example 4 Four types of test pieces were obtained in the same manner as Comparative Example 3, except that the polymerization reaction was carried out without reducing the pressure.

The relationship between the difference in refractive index between the polymer and glass used and the transmittance of each test piece is shown as a curve in FIG.

If a silane coupling agent is not used and the polymer formation reaction is not performed under reduced pressure, the transmittance of the test piece will be extremely low even if the difference in refractive index between the polymer and glass is 0.005 or less. It is clear that it is low.

Example 6 20 parts by weight of silver chloride-containing photochromic phosphate glass (N ²⁰ _D = 1.541) with a particle size of 88 to 350 μm, methyl methacrylate-styrene copolymer (trademark “Denka
TX-100-LS”, manufactured by Denki Kagaku Kogyo Co., Ltd., N ²⁰ _D =
1.541) 100 parts by weight and 0.1 of the same vinyltrimethoxysilane coupling agent as used in Example 4
The weight parts were mixed under reduced pressure of 5 × 10 ^-3 Torr, and 250
After injection molding to a thickness of 3 mm at 1000 Kg/cm ² at ℃, 2
It was sandwiched between two glass plates and compressed at 240°C to form a 1.5 mm sheet.

Comparative Example 5 1.5 was produced directly by injection molding using the same composition as used in Example 6 and under the same conditions as Example 6.
A sheet of mm was obtained.

The transmittance of the obtained sheet at 550 nm was about 20% lower than that of the sheet of Example 6.

It is clear that when the surface of the molded sheet is not smooth, the transmittance is significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the light reflection mechanism of the molded product of the present invention, FIG. 2 is a graph showing the photochromic effect of the molded product obtained by the example of the present invention, and FIG.
Graphs 4 and 5 showing the transmittance of the molded bodies obtained in the examples of the present invention show the relationship between the mixing conditions of the synthetic resin and photochromic glass, the presence or absence of a silane coupling agent, and the transmittance. This is a graph showing.

Claims (1)

[Scope of Claims] 1 (i) (a) 100 parts by weight of a synthetic resin with a transmittance of 40% or more, (b) particle size of 37 to 350 μm containing silver halide
(c) 0.015 to 70 parts by weight of photochromic glass granules; and (c) 0.015 to 70 parts by weight of photochromic glass granules.
A blend comprising 8 mg of a coupling agent and (ii) the difference in refractive index between the synthetic resin and the photochromic glass is ±0.005 or less is mixed under a reduced pressure of at least 5×10 ⁻¹ Torr, and then molded; 1. A method for producing a photochromic molded article, which comprises compressing the molded article to make its surface smooth.