JP5058709B2 - Infrared laser light shielding film - Google Patents

Description

  The present invention is a laser light shielding film with excellent workability by calendar, inflation, extrusion, etc., and excellent durability and weather resistance (UV resistance), and particularly absorbs widely from the near infrared region to the far infrared region. The present invention relates to a laser light shielding film that can be used.

At present, ultraviolet lasers, visible light lasers, infrared lasers, and the like are used in various fields, and among them, many infrared lasers that output laser light of 780 nm or more are used.
Infrared lasers are absorbed by many substances and become heat, so that various materials can be melted, so they are widely used in laser marking, various laser processing, medical fields, etc., including cutting steel sheets and welding metals. .

As this infrared laser, lasers that output laser light of 780 nm or more such as LD excitation solid laser, lamp excitation solid laser, fiber laser, disk laser, hybrid laser, and CO ₂ laser are known. In general, it is very energetic and dangerous to hit human eyes. Therefore, the laser generating device is often used in a sealed area from the viewpoint of safety. Since it is not preferable from the viewpoint of safety that the working situation inside such a sealed area cannot be confirmed from the outside, it is usually preferable to provide the sealed area by partitioning with a transparent glass plate, partition, curtain or the like.
Therefore, development of a film that is transparent and can shield the laser beam is underway. However, there is no laser light shielding film that can absorb all wavelengths from the near-infrared region to the far-infrared region (see Non-Patent Document 1). There was a problem that a film had to be selected.

  Conventionally, as a near-infrared shielding film, 1) a kneaded film in which an infrared-absorbing dye is blended with a resin, 2) an interference film that transmits a specific wavelength by laminating layers having different refractive indexes, and interfering transmittance, 3) A film having a layer in which metal powder (particles) is dispersed has been proposed.

Among the above proposals, many laser light shielding films using infrared absorbing dyes such as 1) are distributed, but as these infrared absorbing dyes, organic cyanine dyes and the like are often used, There was a problem in weather resistance (UV resistance).
In addition, the infrared absorbing dye has a good laser light shielding property near 1000 nm, but has a problem that it cannot absorb a wide range of wavelengths up to 1200 nm or more.
Furthermore, it is known that the above infrared absorbing dyes are generally sensitive to heat, and when kneaded into a resin with a calendar, an extruder, etc., the processing temperature cannot be raised (workability is poor) and can be obtained. In many cases, the appearance of the film was not good.

In the laser light shielding film as in 2), it is necessary to adjust the refractive index of each layer and the wavelength of transmitted light, and it is considered that it takes a lot of cost to produce a practical interference film.
In the laser light shielding film using metal particles such as ITO (indium-containing tin oxide) and ATO (antimony-containing tin oxide) as in 3), it is necessary to increase the amount of addition and adhesion of these metal particles. However, when the addition amount or the adhesion amount is increased, the reflectance in the near-infrared region also increases, and there is a risk that the laser beam will bounce back to the operator and the visible light transmittance is extremely reduced.

In addition, the present inventor has previously proposed a heat ray absorbing sheet that transmits visible light and blocks infrared rays (see Japanese Patent Application No. 2006-351005 (Patent Document 1)).
LASER EYE PROTECTOR AND FILTER Yamamoto Kogyo Co., Ltd. Japanese Patent Application No. 2006-351005 WO2005 / 037932 JP 2005-187323 A

  In consideration of the present situation as described above, the present invention has good workability by calendering, inflation, extrusion, etc., is excellent in durability and weather resistance (UV resistance), and can absorb a wide range from the near infrared region to the far infrared region. It is an object to provide a laser light shielding film.

The present inventors have revealed that extensive investigations to solve the above problems, a tungsten oxide used in the heat-absorbing sheet of the previous suggestions by the present inventor that describes above, infrared wide region to the far infrared region from near-infrared region The knowledge that it can absorb a laser beam effectively was acquired.
The present invention has been made under this finding, and the gist thereof is as follows.
(1) an infrared laser beam-shielding film made of a synthetic resin, the tungsten oxide particles child comprises 2.5 to 6.0 g / m ^2, the optical density (OD level) in the wavelength region of 1000~20000nm is 2 or more der is, infrared laser light-shielding film visible light transmittance is equal to or less than 30%.
(2) Thickness is 0.1-2.0 mm , The infrared laser light shielding film as described in said (1) characterized by the above-mentioned.

According to the laser light shielding film of the present invention, any wavelength from the near infrared region to the far infrared region in the infrared laser can be effectively absorbed. For this reason, by using the laser light shielding film of the present invention, it can correspond to various infrared lasers such as LD excitation solid laser, lamp excitation solid laser, fiber laser, disk laser, hybrid laser, CO ₂ laser, etc. There is no need to change the film for each oscillation wavelength.

Further, the laser light shielding film of the present invention has no problem in processing by calendering, inflation, extrusion and the like. Therefore, it is possible to form a long object with a good appearance, so that it can be applied to wide curtains, and can be applied to a wide range of curtains. It can be applied directly as it is, and it can be used as an easy operation when it deteriorates.
Furthermore, the laser light shielding film using tungsten oxide and / or lanthanum hexaboride according to the present invention maintains a higher visible light transmittance than a film using a conventional organic infrared absorbing dye or metal powder. In addition, since the optical characteristics hardly change over time, and has excellent durability and weather resistance (UV resistance), the industrial utility value is extremely large.

The synthetic resin (base resin) that is the base of the laser light shielding film of the present invention may be any synthetic resin as long as it is used for ordinary films and sheets. Is appropriately selected.
Examples of the synthetic resin used in the present invention include a vinyl chloride resin, a polyolefin resin, a polyester resin, a polycarbonate resin, an acrylic resin, and the like, particularly in terms of weather resistance and workability. Resin and polyolefin resin can be preferably used. Depending on the application, two or more of the above resins can be used in combination.

Examples of vinyl chloride resins include vinyl chloride homopolymer resins, copolymer resins of vinyl chloride and other monomers, mixtures of two or more of these, or vinyl chloride homopolymer resins and copolymer resins and other resins. A blend of resins can also be used (hereinafter, these are collectively referred to as a vinyl chloride resin).
Examples of other monomers copolymerized with vinyl chloride include vinyl acetate, ethylene, propylene, maleic acid ester, methyl methacrylate, methacrylic acid ester, acrylic acid ester, higher vinyl ether, and the like. These may be used alone or in combination of two or more. Can also be used together.
Other resins blended with the vinyl chloride resin include ethylene-vinyl acetate copolymer resin, acrylonitrile-butadiene-styrene copolymer resin, acrylonitrile-butadiene copolymer resin, polyurethane resin, chlorinated polyurethane resin, polymethacrylate resin, etc. These can be blended alone or in combination of two or more.

  Examples of the polyolefin resin include α-olefin homopolymers and copolymers with different monomers mainly composed of α-olefins, and specifically, polyethylene, polypropylene, ethylene-propylene copolymers. , Ethylene-butene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, and the like. These may be used alone or in combination of two or more. Can also be used together.

  Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polycyclohexane terephthalate, polytrimethylene terephthalate, and the like. These may be used alone or in combination of two or more.

The laser light shielding film of the present invention contains 1.0 to 18 g / m ^{2 of} tungsten oxide particles and / or lanthanum hexaboride particles in the synthetic resin as described above, and has an optical density (OD level) at a wavelength of 1000 to 20000 nm. Is 2 or more.
The content of the tungsten oxide particles and / or the lanthanum hexaboride particles is 1.0 to 18 g per 1 m ² regardless of the thickness of the laser light shielding film. If it is less than 1.0 g / m ² , the laser beam having large energy cannot be sufficiently absorbed. Moreover, even if it exceeds 18 g / m ² , this effect is not only saturated, but the tungsten oxide particles and / or the lanthanum hexaboride particles may be aggregated, resulting in poor appearance.

For the purpose of improving the safety and workability of laser workers, the laser light shielding film of the present invention is provided with the provisions of JIS-A-5759 in order to ensure the visibility to which the object can be observed in each work. It is preferable that the visible light transmittance calculated based on is 30% or more.
In order to obtain such visible light transmittance, the content of tungsten oxide particles in the laser light shielding film 1 m ² is preferably 2.5 to 6.0 g. When it is within the range of 2.5 to 6.0 g / m ² , it has a laser light shielding effect and has a good visible light transmittance of 30% or more, so that safety and visibility are sufficiently ensured. Can do.

In the present invention, it is important that the optical density (Optical Density level) in the wavelength region of 1000 to 20000 nm is 2 or more, preferably 4 or more.
The optical density (hereinafter also referred to as “OD level”) is obtained by OD = −log (I ₀ / I) (I: transmitted light intensity, I ₀ : incident light intensity), and is an attenuation factor of transmitted light. (%). The OD level depends on the wavelength of incident light. When OD = 0, the attenuation factor is 0 (ie, 100% transmittance), and when OD = 1, the attenuation factor is 1/10 (ie, 10% transmittance). When OD = 2, the attenuation rate is 1/100 (that is, the transmittance is 1%). As the OD increases by an integer, the attenuation rate increases 10 times. Accordingly, in the field relating to laser light shielding, it is said that the greater the OD level, the greater the shielding property of laser light.
The upper limit of the OD level is not particularly limited, and is preferably higher. If the OD level of the shielding film is 2 or more, the film having excellent shielding properties desired in the present invention can be obtained even in consideration of the intensity of laser light and the distance from the output position.

The laser light shielding film of the present invention can be used in places where infrared laser light shielding is required. For example, the laser light shielding film is used by being attached to a partition (partition) for partitioning a laser light use region or a window for looking into the region. Also good.
At this time, self-tackiness may be imparted to the laser light shielding film itself by increasing the blending amount of the plasticizer or adding a tackifier. Alternatively, an adhesive layer may be provided on either surface of the laser light shielding film.

  The thickness of the laser light shielding film is not particularly limited as long as it is a thickness that can be used as a general laser light shielding film. For example, the thickness is about 0.1 to 2.0 mm. When imparting properties, 0.2 to 0.3 mm is preferable from the viewpoints of ease of operation, self-adhesive function, and the like.

  The tungsten oxide particles used in the present invention include, for example, a general formula WyOz (W is tungsten) as described in WO2005 / 037932 (Patent Document 2), JP-A-2005-187323 (Patent Document 3), and the like. , O is oxygen, tungsten oxide fine particles represented by 2.2 ≦ z / y ≦ 2.999), or general formula MxWyOz (where M is H, He, alkali metal, alkaline earth metal, Rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn , Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I Element, W is tongue Down, O is oxygen, fine particles of composite tungsten oxide expressed by 0.001 ≦ x / y ≦ 1,2.2 ≦ z / y ≦ 3.0).

  As the lanthanum hexaboride particles used in the present invention, those usually used in heat ray absorbing sheets are preferably used.

By including a specific amount of such tungsten oxide particles and / or lanthanum hexaboride particles per 1 m ² of the film, not only the wavelength near 1000 nm output from the YAG laser or the like, but also the wavelength around 10000 nm output from the CO ₂ laser or the like is output. It can absorb a wide range up to the far infrared region.
Moreover, compared with metal powders such as ITO and ATO, infrared laser light can be shielded more efficiently despite the addition of a small amount, and the visible light transmittance of the resulting film can be improved.

  In particular, tungsten oxide particles are preferably used for ensuring visibility because visible light transmittance is unlikely to decrease even when added in a large amount. In addition, since the tungsten oxide particles themselves are excellent in weather resistance, there is no hindrance to use in places such as outdoors or exposed to the outside air.

The dispersed particle size of the tungsten oxide particles and lanthanum hexaboride in the laser light shielding film is preferably 800 nm or less in the average particle size D (50).
If a material larger than this (D (50) = 800 nm) is used, the visible light transmittance is lowered, the transparency may be lowered, and a foreign matter is likely to be present on the film, which is not preferable in appearance.

If tungsten oxide particles and lanthanum hexaboride particles are not uniformly dispersed in the laser light shielding film, the ability to shield various wavelengths of incident laser light (a wide wavelength region of 1000 to 20000 nm) cannot be sufficiently exhibited. There is a fear. In addition, if the shielding film is deformed or is not sufficiently dispersed, tungsten oxide particles and lanthanum hexaboride particles may be aggregated, which is not preferable.
In order to enhance the dispersibility in the base synthetic resin, for example, the surface of tungsten oxide particles or lanthanum hexaboride particles may be coated with a coating agent, or a dispersant or the like may be appropriately coated together with the base material. You may add to a synthetic resin.
As this coating agent, a coupling agent containing an element such as Si, Ti, Zr, or Al is used. For example, a silane coupling agent such as trimethoxysilane is preferably used.
Moreover, as a dispersing agent, various surfactants, phosphate ester compounds, etc. are used suitably.

In addition, when the base synthetic resin is a polyvinyl chloride resin or the like, it is common to add a plasticizer having good dispersibility to the synthetic resin.
In the present invention, the required amount of tungsten oxide particles is dispersed in an additive such as a plasticizer in advance, and the dispersed additive is added to a synthetic resin (which is the base material of the laser light shielding film) to achieve uniform dispersion. May be achieved.
By the method as described above, uniform dispersibility of tungsten oxide particles or lanthanum hexaboride particles in a synthetic resin can be enhanced.

  Examples of the plasticizer include phthalate plasticizers such as di-2-ethylhexyl phthalate (DOP), diisononyl phthalate (DINP), and butyl benzyl phthalate (BBP), and phosphoric acids such as tricresyl phosphate (TCP). Ester plasticizers, adipic acid ester plasticizers such as di-2-ethylhexyl adipate (DOA), sebacic acid ester plasticizers such as di-2-ethylhexyl sebacate (DOS), di-2-ethylhexyl (DOZ) Such as azelaic acid ester plasticizers such as polypropylene adipate (PPA), and chlorinated aliphatic ester plasticizers such as chlorinated paraffin. These may be used alone or in combination of two or more. You can also.

Furthermore, in the laser light shielding film of the present invention, as necessary, together with the above-described tungsten oxide particles and lanthanum hexaboride particles, a dispersant, a plasticizer, an antistatic agent, a flame retardant, a (light) stabilizer, A lubricant, a colorant, a viscosity modifier, and other various additives can be blended. Regarding the addition of a colorant or the like, it is necessary to consider so as not to impair the transmittance in the visible light region.
As a method for forming a laser light shielding film, a synthetic resin composition containing tungsten oxide particles, lanthanum hexaboride particles and other additives obtained as described above is used for general sheet or film molding. It can be formed by various molding methods such as calendar molding, extrusion molding, inflation molding and cast molding.

By containing an antistatic agent in the laser light shielding film, it can be made suitable for use in a clean room or the like.
As the antistatic agent, nonionic surfactants, cationic surfactants, anionic surfactants and the like are used.

By including the flame retardant in the laser light shielding film, it is possible to efficiently prevent the laser light from being stored and penetrating the film or carbonizing the film.
As the flame retardant, a chlorine compound, a bromine compound, a phosphorus compound, and other various inorganic compounds are used.

  The light stabilizer may be at least one selected from benzophenone compounds, cyanoacrylate compounds, benzotriazole compounds, salicylic acid ester compounds, triazine compounds, and hindered amine compounds.

The laser light shielding film of the present invention may be a laminate of two or more layers as long as at least one layer is a synthetic resin sheet in which tungsten oxide particles and / or lanthanum hexaboride particles are added to a synthetic resin.
Thus, in the laser light shielding film of this invention, the normal sheet | seat may be laminated | stacked and the function other than thermal insulation performance may be provided.

For example, a protective layer for the purpose of preventing scratches on the surface can be provided.
For this protective layer, for example, a commonly used surface treatment agent consisting of a simple substance such as polyurethane, polyvinyl acetate, acrylic resin, two or more copolymers, a mixture of two or more, etc. is used as a laser light shielding film. What is necessary is just to provide by apply | coating on the surface.

[Examination of OD level and light transmittance]
In accordance with the composition of the composition shown in Table 1, after the infrared shielding agent was dispersed in the plasticizer in advance, it was kneaded with a Banbury mixer together with other compounds, and then the thickness shown in Table 1 on the calendar with a final roll temperature of 175 ° C. Film was obtained.
About each obtained film, A) OD level in 780-2100 nm, B) OD level in 10000 nm, C) Visible light transmittance (%), D) Haze, E) Surface appearance was measured, and the result was combined. Table 1 shows.

(Raw materials used)
-Polyvinyl chloride (average degree of polymerization 1050)-Kaneka's product name "S1001"
・ Cesium tungsten oxide (Cs _0.33 WO ₃ )
・ Lantan hexaboride ・ Plasticizer: Product name "DHP" manufactured by CG Esther
-Epoxidized soybean oil: Product name “W-100EL” manufactured by Dainippon Ink & Chemicals, Inc.
Ba-Zn composite stabilizer: Adeka's product name "AC-255"
・ Lubricant: Nippon Kasei Co., Ltd. Product name “Bisamide”
-Light stabilizer: Benzotriazole compound (trade name “MAF-613” manufactured by Akishima Chemical Co., Ltd.)

As shown in the following formula and Table 2, the OD level is a value obtained by logarithmically expressing the attenuation rate of transmitted light.
A) The OD level at a wavelength of 780 to 2100 nm, B) The OD level at a wavelength of 10000 nm was measured for incident light intensity and transmitted light intensity with a self-recording spectrophotometer (trade name “V-570” manufactured by JASCO Corporation) It calculated | required with the following formula. In the present invention, a film having an OD level value of 2 or more is regarded as having sufficient laser light shielding properties.
OD = -log (I ₀ / I) I: transmitted light intensity I ₀ : incident light intensity

C) Visible light transmittance is an average light transmittance in a 380 to 780 nm region, and was measured with a self-recording spectrophotometer (trade name “V-570” manufactured by JASCO Corporation).
D) Haze (unit%) was measured based on JIS K6714.
E) The surface appearance was visually evaluated.
○: No appearance defect ×: Foreign matter is seen on the surface

From Table 1, Examples 1-5 had an OD level of 2 or more in any wavelength region of 780 to 2100 nm and 10000 nm, and a satisfactory shielding property as a laser light shielding film of the present invention was obtained.
In particular, in Examples 1 to 3, since the visible light transmittance is high and the haze is small, it can be seen that a transparent laser light shielding film was obtained.

The laser light shielding film of the present invention is suitable for a wide range of fields as a multi-wavelength combined type capable of absorbing a wide range from a wavelength near 1000 nm output by a YAG laser or the like to a wavelength in the far infrared region near 10000 nm output by a CO ₂ laser. Can be used.
For example, since it is possible to form a long film having a good appearance as well as a shield and panel application, it is also suitable as a sticking film for a wide curtain, a partition (partition), a viewing window, and the like.

Claims (2)

An infrared laser light-shielding film made of a synthetic resin, the tungsten oxide particles child comprises 2.5 to 6.0 g / m ^2, Ri der optical density (OD level) of 2 or more in the wavelength range 1000~20000nm An infrared laser light shielding film having a visible light transmittance of 30% or more . The infrared laser light shielding film according to claim 1, wherein the thickness is 0.1 to 2.0 mm .