JP7458219B2 - Heat shielding resin composition and heat shielding film - Google Patents

Description

The present invention relates to a heat-shielding resin composition and a transparent heat-shielding film formed using the same.

Plastic film is lightweight, flexible, easy to assemble and install, and is durable enough to be used outdoors, so it is used in tent warehouses, event tents, work tents, agricultural greenhouses, amusement spaces, and events. It is widely used for membrane structures such as spaces and rainy sports fields. In addition, films with particularly high visible light transmittance are being used not only for the above-mentioned membrane structures, but also for forming the whole or part of the roof of a building, and for use in sheet shutters for entrances and exits.

However, in general, films made only of plastic are easily transparent to heat rays, and buildings made from them, such as agricultural greenhouses, can become extremely hot inside under strong summer sunlight. If you engage in long-term activities in such a high-temperature environment, you may suffer from heatstroke. Therefore, efforts have been made to add or coat a substance that absorbs or diffuses heat rays into plastic films.

This is true not only for humans and animals, but also for plants. For example, when growing in agricultural greenhouses and exposed to strong summer sunlight, plants may suffer from burnt leaves, withered seedlings, high-temperature damage, etc. It has a negative effect on growth.

Therefore, conventionally, as a method of suppressing the poor growth of plants due to strong sunlight in summer, a method has been implemented in which the outer surface of the sheet material of the greenhouse is covered with a light-shielding net. However, since the shading net itself is expensive, there is a problem in that the preparation cost is high, and there is also a problem in that it is not easy to remove the installed shading net when the implementation is finished.

Therefore, in order to solve the above problem, a method has been taken to lower the temperature inside the agricultural greenhouse by adding or coating a substance that absorbs or diffuses heat rays to the film used for the agricultural greenhouse. I've been exposed to it.

For example, Patent Document 1 describes an agricultural shade agent containing water, a water-based binder, titanium oxide, and calcium carbonate, which is sprayed on the outer surface of a sheet material to suppress unevenness on the outer surface. It has been proposed that it is possible to form a light-shielding surface with a light-shielding structure formed thereon, and also to form a light-shielding structure that is less likely to run off due to rain or the like.

Patent Document 2 discloses that a heat-insulating agricultural film made of mica coated with thermoplastic resin and titanium oxide is transparent and has excellent heat ray-shielding properties, and is suitable for use as an outer lining for agricultural greenhouses. It is proposed that it be done.

Patent Document 3 proposes an agricultural film made of a resin film having a visible light transmittance of 85% or more, a solar radiation transmittance of 80% or more, and a solar absorption rate of 8 to 15%, as determined in accordance with JIS R3106. By incorporating hexaboride particles as an infrared absorbing filler into the agricultural film, the above-mentioned visible light transmittance can be achieved, and as a result, plants can be cultivated successfully in both winter and summer. . The specification also mentions the use of antimony-doped tin oxide (hereinafter also referred to as "ATO") or tin-doped indium oxide metal thin film as a method that satisfies the above conditions.

Patent Document 4 discloses a flexible sheet including a near-infrared shielding layer, wherein the near-infrared shielding layer has a sea-island structure made of an incompatible mixture of synthetic resin blends, and further in the sea-island structure, A near-infrared shielding sheet has been proposed in which either the component or the island component contains tungsten oxide fine particles and/or composite tungsten oxide fine particles, and has high light transmittance in the visible light region. , transparent, colored transparent, semi-transparent, colored semi-transparent, colored opaque, etc., with a high degree of freedom in terms of visibility and hue, and has excellent near-infrared shielding properties, so it has excellent heat shielding properties and infrared noise shielding properties. Especially for sunshade tents, sunshade monuments, decorative tents, tent warehouses, event tents, truck hoods, agricultural and gardening sheets, blinds, sheet shutters, partitions, lighting shades, membrane materials for optical ceilings, membrane materials for internally illuminated signboards, etc. It is said that it will be suitably used.

JP2015-006154 JP2007-111002 JP2012-021056 JP2011-093280

Although these conventional technologies differ in that they are contained in a film or coated, they all attempt to suppress excessive temperature rises in agricultural greenhouses, etc. by shielding, absorbing, or reflecting heat rays. It is something.

Films used in agricultural greenhouses are preferably transparent so that the condition of plants, etc. can be observed from the outside. Also, being transparent means that it allows light necessary for photosynthesis, which is what plants need to grow, to pass through, and therefore does not impede the growth of plants, etc.

However, when an agricultural greenhouse is exposed to sunlight, its interior becomes warm, and the warm air gathers upwards.If the greenhouse continues to be heated, the warm air above does not go down, but radiates through the greenhouse's film and glass. There are no other factors that can lower the temperature inside the greenhouse other than the amount of heat generated by the heat, so if it is sunny and sunlight is shining, the temperature inside the greenhouse will continue to rise, especially in the upper part.

Crops in greenhouses are more affected in the upper part of the house than in the lower part. There are many growing points in the upper part of crops that are susceptible to direct sunlight, where buds and young leaves grow, but as they are still in the process of growing, they are easily affected by temperature, and this area is susceptible to high temperature damage. In the worst case scenario, the plant may wither and die.

When sunlight is brought in during the summer, not only in agricultural greenhouses but also in rooms where humans and animals are active, it is necessary to prevent excessive temperature rises, but even in this case, the temperature easily rises and heat accumulates. It is believed that if we can suppress the rise in temperature in the upper part of the house, we will be able to live a more comfortable life.

Therefore, an object of the present invention is to provide a heat-shielding resin composition used for producing a transparent heat-shielding film and the heat-shielding film.

As a result of intensive studies, the present inventors have discovered that the heat shielding effect is mainly due to light absorption by combining ATO particles with a material having a light scattering effect (light diffusing material), in particular mica particles coated with titanium oxide. The inventors have discovered that the above-mentioned problems can be solved, and have completed the present invention.

That is, the present invention
( 1 ) A heat shielding resin composition comprising a thermoplastic resin, antimony-doped tin oxide particles, and titanium oxide-coated mica particles, wherein the antimony-doped tin oxide is added to the total amount of the heat shielding resin composition. A heat shielding resin composition, characterized in that the content of the particles is 0.5 to 4% by mass, and the content of the titanium oxide-coated mica particles is 0.5 to 3% by mass ,
( 2 ) The heat shielding resin composition according to (1), wherein the antimony-doped tin oxide particles have a 50% volume particle diameter of 80 to 130 nm as determined by particle size distribution measurement using a dynamic light scattering method;
( 3 ) The titanium oxide-coated mica particles have a 10% particle size of 3 μm or more and a 90% particle size of 80 μm or less, and a titanium oxide coverage of 10 to 70% by mass, as determined by particle size distribution measurement using a laser diffraction method. The heat shielding resin composition according to any one of (1) to (2) , characterized by
( 4 ) The heat shielding resin according to any one of (1) to (3), wherein the thermoplastic resin is at least one selected from olefin resins and vinyl chloride resins. Composition,
( 5 ) Melting and kneading antimony-doped tin oxide particles, titanium oxide-coated mica particles, and a thermoplastic resin to obtain a high-concentration heat-shielding resin composition;
Melting and kneading the high concentration heat shielding resin composition and the diluting thermoplastic resin;
The method for producing a heat shielding resin composition according to any one of (1) to (4) , comprising:
( 6 ) A heat shielding film comprising the heat shielding resin composition according to any one of (1) to (4) and having an average visible light transmittance of 70% or more;
( 7 ) The mass ratio of the antimony-doped tin oxide particles and the titanium oxide-coated mica particles is 12:1 to 1:12, and the total content of the antimony-doped tin oxide particles and the titanium oxide-coated mica particles is 0.8 to 2.4 g/m ² , the heat shielding film according to (6) ,
( 8 ) The heat shielding film according to (6) or (7) , wherein the film has a thickness of 0.01 to 0.3 mm;
( 9 ) The heat shielding film according to any one of (6) to (8), which is for agricultural use;
It is.

Despite its high transparency, the heat shielding film of the present invention not only can effectively suppress the temperature rise in the interior space covered by sunlight when it is irradiated with sunlight, but also the temperature rise in the upper part of the film. suppress. In the present invention, the effect of suppressing the temperature rise in the upper part is defined as the upper heat shielding effect. Therefore, in agricultural greenhouses, the temperature rise on the upper side of crops, which is susceptible to high-temperature damage, can be suppressed, so it can be suitably used as a heat shielding film for agricultural greenhouses. This can also improve the unpleasant situation where only the upper part of a living space for humans or animals becomes extremely hot when exposed to sunlight or other light.
Furthermore, since the heat shielding film of the present invention uses two types of heat shielding agents with different action mechanisms, it can be used as a film that can effectively shield heat rays.

FIG. 2 is a schematic diagram showing a measuring device for a heat shielding test.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated in detail. Note that this embodiment is only one mode for carrying out the present invention, and the present invention is not limited to this embodiment, and various changes can be made without departing from the gist of the present invention. .

In this specification, "~" indicates that the upper limit value and the lower limit value are included, unless otherwise specified.

The heat shielding resin composition of the present invention includes a thermoplastic resin, antimony-doped tin oxide particles, and titanium oxide-coated mica particles.

The ATO particles contained in the heat-shielding resin composition of the present invention exhibit a heat-shielding effect mainly by absorbing heat rays, and are an inorganic compound obtained from antimony oxide (Sb ₂ O ₃ ) and tin oxide (SnO ₂ ), and may be used by pulverizing a commercially available powder, or may be used as a dispersed product, or may be produced by a conventionally known method, etc. For example, commercially available products include SN-100P and SN-100D (both manufactured by Ishihara Sangyo Kaisha, Ltd.), etc.

The 50% volume particle diameter of the ATO particles is preferably 80 to 130 nm as measured by particle size distribution using a dynamic light scattering method. If the diameter is less than 80 nm, particles tend to form aggregates, making it difficult to form a film, and if it exceeds 130 nm, transparency may be insufficient.

The content of the ATO particles in the heat-shielding resin composition is preferably 0.5 to 4% by mass, and more preferably 1 to 4% by mass. If it is less than 0.5% by mass, the heat-shielding effect is insufficient, and if it is more than 4% by mass, the transparency of the heat-shielding film may not be maintained. In addition, a heat-absorbing material other than ATO particles may be used in combination.

In addition to the ATO particles, the heat shielding resin composition contains a material with a light scattering effect (light diffusing material), thereby providing a heat shielding effect to agricultural greenhouses, etc., and particularly an effect of suppressing temperature rise in the upper part. can be strengthened.

The light diffusing material is thought to have the effect of suppressing the temperature rise in the upper part of an agricultural greenhouse etc. mainly by diffusing heat rays, and is at least one type selected from inorganic particles or organic particles. is preferred.
Examples of the organic particles include polymethyl methacrylate particles, acrylic-styrene copolymer particles, melamine particles, polycarbonate particles, styrene particles, crosslinked polystyrene particles, polyvinyl chloride particles, benzoguanamine-melamine formaldehyde particles, and the like.
Examples of the inorganic particles include mica particles coated with titanium oxide (mica coated with titanium oxide), glass beads, silica particles, zeolite, and the like. Among them, titanium oxide-coated mica particles are preferably used because they have excellent transparency and a large light scattering effect.

If the 10% particle diameter of the titanium oxide-coated mica particles is small, the heat ray shielding effect will be reduced, so it is preferably 3 μm or more, more preferably 5 μm or more. In addition, if the 90% particle diameter is large, the transparency of the film will decrease, so it is preferably 80 μm or less, more preferably 65 μm or less.

In the present invention, the 10% particle diameter of the titanium oxide-coated mica particles is the mass standard of the titanium oxide-coated mica particles obtained by measuring the particle size distribution of the titanium oxide-coated mica particles to be measured by a laser diffraction method. In the particle size distribution of This refers to the particle size that is 90% cumulative.

The titanium oxide coverage in the present invention refers to the titanium dioxide content in mica whose surface is coated with titanium oxide, expressed as a mass ratio.
In the titanium oxide-coated mica particles, if the coverage rate of mica with titanium oxide is low, the heat shielding effect may be insufficient. However, even if the coverage rate exceeds 70%, the heat shielding effect will not increase. Preferably, 30 to 60% is more preferable. Moreover, any of the rutile type, anatase type, and brookite type can be suitably used as the titanium oxide for coating the mica.

The titanium oxide-coated mica particles are commercially available. For example, the product names are Mearlin Exterior Fine Red439V, Mearlin Fine Violet539V, Mearlin Super Violet9530Z, and Mearlin Exterior CFS Super Violet530. 3Z (manufactured by BASF), Iriotec9770, Iriodin223, Iriodin100, Iriodin120 (manufactured by Merck), etc. .

The content of the titanium oxide-coated mica particles in the heat shielding resin composition is preferably 0.5 to 3% by mass, more preferably 0.5 to 2.5% by mass. If it is less than 0.5% by mass, sufficient light diffusivity will not be exhibited, and if it is more than 3% by mass, the transparency of the thermal barrier film produced therefrom will be reduced. Further, a light diffusing material other than titanium oxide coated mica particles may be used in combination.

The thermoplastic resin used in the heat shielding resin composition of the present invention may be any thermoplastic resin as long as it can form a highly transparent film. Specifically, polyethylene, ethylene-vinyl acetate copolymer, polypropylene, ultra-high molecular weight polyethylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinylidene chloride resin, polyvinyl acetate, acrylic resin, ABS resin. , AS resin, MBS resin, polystyrene, polyvinyl alcohol, styrene block copolymer, polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polyester, fluorine resin, butyral resin, styrene-maleic acid copolymer, polyurethane resin , alkyd resins, rubber resins, cyclized rubber resins, celluloses, polybutadiene, polyimides, and the like. At least one kind selected from these is preferable, and two or more kinds may be used in combination. Among these, polyolefin resins, vinyl chloride resins, and fluororesins, which are commonly used in agricultural greenhouses, are preferred.

(Basically as written in the book)
Various additives may be added to the heat shielding resin composition of the present invention as necessary. Specifically, waxes, metallic soaps, lubricants, heat stabilizers, plasticizers, processing aids, light stabilizers, ultraviolet absorbers, antioxidants, fungicides, flame retardants, fillers, reinforcing agents, and crosslinking agents. agents, reinforcing materials, lubricants, antifogging agents, antistatic agents, conductive materials, foaming agents, lightweight fillers, coloring agents, etc., but any known and commonly used materials can be used in heat shielding resin compositions. It can be selected as appropriate within a range that does not impair the properties of the product.

There is no particular restriction on the production of the heat-shielding resin composition of the present invention, but it can be produced by directly melt-kneading ATO particles and titanium oxide-coated mica particles with the thermoplastic resin, or by melt-kneading ATO particles and titanium oxide-coated mica particles with the thermoplastic resin at a high concentration to produce a high-concentration heat-shielding resin composition (hereinafter referred to as "master batch"), and diluting this master batch with the thermoplastic resin (hereinafter, the thermoplastic resin used to dilute the master batch is referred to as "thermoplastic resin for dilution"). The master batch can be produced by mixing ATO particles and titanium oxide-coated mica particles together. It is also possible to mix ATO particles and titanium oxide-coated mica particles separately with a thermoplastic resin, and then mix the two together to produce the master batch of the present invention. The use of a master batch or the use of a heat-shielding resin composition to produce a heat-shielding film can be appropriately selected in consideration of the advantages and disadvantages of each.
The content of the ATO particles in the master batch is preferably 1 to 59% by mass, more preferably 5 to 40% by mass. The content of the titanium oxide-coated mica particles is preferably 1 to 59% by mass, more preferably 5 to 30% by mass. The combined content of the ATO particles and the titanium oxide-coated mica particles in the master batch is preferably 60% by mass or less, since this makes it difficult to prepare the master batch.
The thermoplastic resin used in the preparation of the master batch and the thermoplastic resin for dilution are preferably the same, but different resins may be used as long as they are compatible with each other.
In the case of melt kneading, a method in which the materials are mixed using a mixer and then melt kneaded using a kneader is preferred. Examples of the mixer include a Henschel mixer, a tumbler, and a ribbon blender. Examples of the kneader include a single-screw extruder, a twin-screw extruder, and a kneader.

The heat-shielding film of the present invention contains the heat-shielding resin composition and is characterized by having an average visible light transmittance of 70% or more.

The average visible light transmittance of the heat shielding film of the present invention is preferably 70% or more because if it is lower than 70%, it will greatly affect the growth of plants. In the present invention, the average visible light transmittance refers to the average light transmittance from 380 to 780 nm, and is the arithmetic average of the light transmittances for each 1 nm.

The light transmittance can be measured using a known device and employing a known method. An example of a known device is the UH4150 UV-Vis-Near-Infrared Spectrophotometer manufactured by Hitachi High-Tech Science Corporation. In addition, when using the above-mentioned UH4150 UV-Vis-Near-Infrared Spectrophotometer manufactured by Hitachi High-Tech Science Corporation, a known method can be used to measure the light transmittance in the measurement range of 175 to 3300 nm under measurement conditions of SCAN SPEED 300 nm/min and SLIT width 5 nm.

There are no particular limitations on the method for forming a heat shielding film from the heat shielding resin composition of the present invention. Examples include known methods such as extrusion molding using a single or twin screw extruder equipped with a T-die, inflation molding using an extruder equipped with a circular die, and calendar molding.

In the heat shielding film of the present invention, it is preferable that the mass ratio of the ATO particles to the titanium oxide-coated mica particles is 12:1 to 1:12 and the total content of the ATO particles and the titanium oxide-coated mica particles is 0.8 to 2.4 g/ ^m2 , and it is more preferable that the mass ratio of the ATO particles to the titanium oxide-coated mica particles is 12:1 to 1:5 and the total content of the ATO particles and the titanium oxide-coated mica particles is 1.2 to 2.2 g/ ^m2 .
If the mass ratio of the ATO particles to the titanium oxide-coated mica particles is out of the range of 12:1 to 1:12, the upper heat shielding effect and transparency are reduced. Even if the mass ratio of the ATO particles to the titanium oxide-coated mica particles is in the range of 12:1 to 1:12, if the total content of the ATO particles and the titanium oxide-coated mica particles is less than 0.8 g/ ^m2 , the heat shielding effect is poor, and if it exceeds 2.4 g/ ^m2 , the light transmittance is reduced.
By blending the ATO particles and the titanium oxide-coated mica particles in the above-mentioned balance, it is possible to preferably achieve both the upper heat shielding effect and transparency, which are the objects of the present invention.

If the thickness of the heat shielding film is too thin, the strength will be insufficient, which is undesirable.On the other hand, if it is too thick, it will be difficult to handle and the light transmittance will tend to be low, so it is generally 0.01 to 0. 3 mm, preferably in the range of 0.02 to 0.25 mm.

The heat shielding film of the present invention has physical properties (rigidity, impact resistance, durability, etc.) and uses required as an agricultural film, as well as performance (pinhole resistance, printability, transparency, design, etc.). Depending on the situation, other layers may be laminated as appropriate to form a laminate having various layer configurations. For example, the heat shielding film may be provided with another layer such as another resin film, synthetic paper, paper, nonwoven fabric, vapor deposited layer, or printed layer, which may be a single layer or a plurality of layers. Of course, these other layers may be processed by printing or the like.

When laminating another layer on the heat shielding film of the present invention, it may be bonded via an adhesive or may be laminated directly without using an adhesive. When adhering via an adhesive, the adhesive used may be a two-component curing adhesive or a one-component curing adhesive. Further, the adhesion mechanism of the adhesive is not particularly limited, and may be any of chemical reaction type, solvent volatilization type, heat melting type, heat pressure type, electron beam curing type, ultraviolet curing type, etc. Further, in the case of adhering without using an adhesive, for example, a method of adhering in a hot melt state such as a coextrusion method, a sandwich lamination method, a thermal lamination method, etc. can be mentioned.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. In addition, in the examples, "parts" represent "parts by mass."

<Preparation of heat shielding resin composition>
Heat shielding resin composition No. 1 of Example 1 1 was created using the following procedure.
96.5 parts of low density polyethylene (hereinafter referred to as "LDPE", trade name UBE polyethylene F522N, manufactured by Ube Maruzen Polyethylene Co., Ltd.), 0.5 part of ATO particles (powder type, SN-100P, manufactured by Ishihara Sangyo Co., Ltd.) and 3.0 parts of titanium oxide-coated mica particles (Iriodin 223, manufactured by Merck & Co., Ltd.) were put into a three-hands mixer, mixed and stirred, and then fed to a single-screw extruder, melt-kneaded at 160°C and extruded as a strand. Thermal barrier resin composition No. 1 is cooled and cut into pellets. I got 1. Using the same procedure, using the raw materials listed in Table 1, and according to the compositions in Tables 2 and 3 (the numbers in the tables represent mass%), the shielding of Examples 2, 4 to 20 and Comparative Examples 1 to 10 was carried out. Thermal resin composition No. 2, 4-30 were produced.

<Preparation of heat-shielding film>
The heat shielding film No. 1 of Example 1 was produced by the following procedure.
Heat-shielding resin composition No. 1 was fed into the supply port of an inflation molding machine and extruded at 160° C. to obtain 0.050 mm heat-shielding film No. 1. Using the same procedure, heat-shielding resin compositions No. 2 and 4 to 30 were used to obtain heat-shielding films No. 2 and 4 to 30 of Examples 2, 4 to 20 and Comparative Examples 1 to 10.

<Production of heat shield film from masterbatch>
The thermal barrier film of Example 3 was produced using a masterbatch containing ATO particles and titanium oxide-coated mica particles.
A masterbatch is made by kneading 70 parts of LDPE, 10 parts of ATO particles, and 20 parts of titanium oxide-coated mica particles using a twin-screw extruder at a molding temperature of 160°C, and discharging the obtained kneaded product from a die. Obtained. 10 parts of the obtained masterbatch and 90 parts of LDPE were blended, put into the supply port of an inflation molding machine, and extruded at 160°C to form a heat shield film No. 0.050 mm. I got 3.

<Average visible light transmittance>
The light transmittance was measured for each heat shield film using an ultraviolet-visible near-infrared spectrophotometer (UH4150, manufactured by Hitachi High-Tech Science Co., Ltd., SCAN SPEED 300 nm/min, SLIT width 5 nm) from 380 to 780 nm, which corresponds to visible light. The transmittance was measured every 1 nm. The average visible light transmittance was determined by arithmetic averaging the measured transmittances. Tables 4 and 5 show the average visible light transmittance, and rated ◎ if it was 75% or more, ◯ if it was 70% or more and less than 75%, and × if it was less than 70%.

<Heat shielding test: Measurement of upper heat shielding effect and lower heat shielding effect>
For each heat shield film, the initial temperature was set to 25°C, and the heat shield effect of the upper and lower parts was measured by the following method.
As shown in the schematic diagram of the measuring device for the heat shield test in Figure 1, a styrofoam 1 with a length of 25.0 cm, a width of 25.0 cm, and a depth of 3.0 cm is A cardboard box 2 with a length of 40.0 cm and a thickness of 0.5 cm is placed, and an opening of 22.5 cm in the length direction and 16.0 cm in the width direction is provided at the center of the top surface of this cardboard box, and this opening is closed. Place the heat shield film 3 on. A temperature sensor 4 for measuring the upper heat shielding effect is placed 15.0 cm below the heat shielding film, and a temperature sensor 5 for measuring the lower heat shielding effect is installed on the table 6 so as to be 34.5 cm below the heat shielding film. An infrared lamp 7 (I-R type infrared bulb 125W, manufactured by Iwasaki Electric Co., Ltd.) is irradiated for 60 minutes from 30.0 cm directly above the heat shielding film, and the temperature before and after irradiation is measured. From a comparison with a film made only of LDPE (hereinafter referred to as "blank"), the upper heat shielding effect (°C) and the lower heat shielding effect (°C) are calculated using the following formula.
Upper heat shielding effect (°C) = (Temperature 15.0 cm below after irradiating the blank - Temperature 15.0 cm below before irradiating the blank) - (Temperature 15.0 cm below after irradiating the heat shield film Temperature - Temperature 15.0cm below before irradiating the heat shield film)
Lower heat shielding effect (°C) = (Temperature below 34.5 cm after irradiation to blank - Temperature below 34.5 cm before irradiation to blank) - (Temperature below 34.5 cm after irradiation to heat shield film) Temperature - temperature below 34.5 cm before irradiation to the heat shield film)
It was determined that the larger the upper heat shielding effect and the lower heat shielding effect (°C), the better the upper heat shielding effect and the lower heat shielding effect. The upper heat shielding effect was evaluated in three stages: ◎: 4°C or higher, ○: 3°C or higher and lower than 4°C, ×: lower than 3°C. The lower heat shielding effect was evaluated in three stages: ◎: 2°C or more, ○: 1°C or more and less than 2°C, ×: less than 1°C, and the results are listed in Tables 4 and 5. For films with a light transmittance evaluation of ×, no heat shielding test was conducted and the films are marked with diagonal lines in the table.

In the heat shielding films shown in Tables 4 and 5, Comparative Example 3 containing only ATO particles at 1.91 g/ ^m2 has a lower heat shielding effect of ○, but an upper heat shielding effect of ×, 60% oxidation. Comparative Example 6, which contained only titanium-coated mica particles at 0.93 g/m ² , was evaluated as poor for both the upper and lower heat shielding effects. On the other hand, in Example 8, the amount of ATO particles was 0.94 g/ ^m2 , which was less than Comparative Example 3, and the amount of 60% titanium oxide-coated mica particles was 0.47 g/ ^m2 , which was less than Comparative Example 6. Both the upper and lower heat shielding effects were evaluated as ◎.
Furthermore, Comparative Example 9, which contained only 30% titanium oxide-coated mica particles at 0.93 g/m ² , was evaluated as × for both the upper and lower heat shielding effects. On the other hand, in Example 12, the amount of ATO particles was 0.94 g/ ^m2 , which was less than Comparative Example 3, and the amount of 30% titanium oxide-coated mica particles was 0.47 g/ ^m2 , which was less than Comparative Example 9. Both the upper and lower heat shielding effects were evaluated as ◎.
From the above, it can be said that by combining ATO particles and titanium oxide-coated mica particles, a synergistic effect on the heat shielding effect, particularly on the upper heat shielding effect, was achieved.
Furthermore, according to Examples 14 to 20, the heat shielding film of the present invention exhibits a heat shielding effect regardless of the thickness as long as the ATO particles and titanium oxide coated mica particles are sufficiently contained in the film. There is.

1 Styrofoam
2 Cardboard box
3 Heat shield film
4 Temperature sensor for measuring upper heat shielding effect
5 Temperature sensor for measuring lower heat shielding effect
6 Table 7 Infrared lamp

Claims (9)

A heat shielding resin composition comprising a thermoplastic resin, antimony-doped tin oxide particles, and titanium oxide-coated mica particles,
The content of the antimony-doped tin oxide particles is 0.5 to 4% by mass, and the content of the titanium oxide-coated mica particles is 0.5 to 3% by mass with respect to the total amount of the heat shielding resin composition. A heat shielding resin composition characterized by the following. The heat shielding resin composition according to claim 1 , wherein the antimony-doped tin oxide particles have a 50% volume particle diameter of 80 to 130 nm as measured by particle size distribution using a dynamic light scattering method. The titanium oxide-coated mica particles have a 10% particle size of 3 μm or more and a 90% particle size of 80 μm or less, and a titanium oxide coverage of 10 to 70% by mass, as determined by particle size distribution measurement using a laser diffraction method. The heat shielding resin composition according to any one of claims 1 to 2 . The heat shielding resin composition according to any one of claims 1 to 3 , wherein the thermoplastic resin is at least one selected from olefin resins and vinyl chloride resins. Melting and kneading antimony-doped tin oxide particles, titanium oxide-coated mica particles, and a thermoplastic resin to obtain a high-concentration heat-shielding resin composition;
Melting and kneading the high concentration heat shielding resin composition and the diluting thermoplastic resin;
The method for producing a heat shielding resin composition according to any one of claims 1 to 4 , comprising: A heat shielding film comprising the heat shielding resin composition according to any one of claims 1 to 4 and having an average visible light transmittance of 70% or more. The heat shielding film according to claim 6, characterized in that the mass ratio of the antimony-doped tin oxide particles to the titanium oxide-coated mica particles is 12 :1 to 1:12, and the total content of the antimony-doped tin oxide particles and the titanium oxide-coated mica particles is 0.8 to 2.4 g/ ^m2 . The heat shielding film according to claim 6 or 7, wherein the film has a thickness of 0.01 to 0.3 mm. The heat shielding film according to any one of claims 6 to 8, which is used for agricultural purposes.

Images