JP4647342B2 - Solar reflective sheet - Google Patents

Description

  The present invention, when used in a sheet-like structure such as a tent or tarp, can effectively suppress an increase in temperature due to sunlight of an object placed inside the structure, and the surface of the sheet It is related with the sheet | seat which has the sunlight reflective performance which can prevent deterioration of the sheet | seat accompanying the temperature rise of.

Conventionally, a material used for a tent or the like is called tarpaulin and generally has a structure in which both surfaces of a fiber base material such as a polyester knitted fabric or a woven fabric are covered with polyvinyl chloride or rubber.
Tarpaulins with such a structure are never good in terms of heat insulation properties, especially in tent warehouses that are used semi-permanently. Of course, it is not comfortable for workers.
Furthermore, the temperature rise in the tent is also a big problem for military tents used in emergency situations and temporary tents used in disasters.

Conventionally, the same tarpaulin or a canvas impregnated with resin has been used as a truck hood. However, as in the case of the above tent, the temperature rise in the truck bed is large during the midsummer day. It is a problem and there are restrictions on the luggage to be carried.

By the way, technology to provide a sheet that reflects sunlight has been used for a long time,
For example, a laminate in which aluminum is vapor-deposited on the surface of a polyester film (Japanese Unexamined Patent Publication No. 2000-71858-Patent Document 1), a sheet containing a specific amount of aluminum powder in a plastic resin (Japanese Unexamined Patent Publication No. 8-81567- Patent Document 2), a heat-shielding color film (Japanese Patent Laid-Open No. 2002-12679-Patent Document 3) and the like formed by mixing two or more kinds of special pigments with a thermoplastic resin film are known.

However, a structure in which aluminum is vapor-deposited on the surface of a polyester film and laminated with polyethylene foam is applied to a simple cooler box, etc., but it is not suitable for long-term use because of its poor surface wear strength. In addition, it is not suitable as a tent sheet material due to strength and thickness problems.
In addition, the sheet as described in Patent Documents 1 and 2 has a structure in which an aluminum vapor-deposited film or an aluminum powder-containing sheet is heated to a high temperature by absorbing light and the film or sheet itself is heated. Although sunlight does not reach the inside of the body directly, indirect heating due to heat propagation is considered, and there is also a concern about deterioration of the film or sheet itself. Moreover, these films and sheets contain a lot of aluminum on the surface. In addition, it is dazzling and not suitable for printing on the surface.

  Furthermore, the sheet and film as described in Patent Document 3 must use an expensive pigment excellent in heat shielding performance, as well as a general inexpensive white titanium oxide compared to such an expensive pigment. In some cases, the pigment has excellent reflection performance. Moreover, although the film can keep the surface temperature low, the film as a whole has a large amount of light transmission, and therefore directly heats an object placed inside the structure using the film. The temperature of this object tends to increase.

As another method for imparting heat shielding properties to the sheet, a method of applying a paint having a heat shielding effect to the surface of the sheet is also conceivable, but the paint itself is more expensive than a general paint, After creating a structure such as a tent, it is necessary to apply paint so that a certain level of performance can be achieved. For example, it is necessary to apply paint many times to make it thicker. There is a problem that it takes time and effort.
JP 2000-71858 A JP-A-8-81567 JP 2002-12679 A

  In consideration of the above points, the present invention solves various problems of heat-insulating films and sheets that have been proposed so far (hereinafter collectively referred to as “sheets”). It is an object to provide a sheet that has light reflection performance, prevents the sheet from deteriorating by preventing the temperature rise of the sheet itself, and can stably maintain excellent sunlight reflection performance over a long period of time. And

The present invention, in order to solve the above problems, a sheet having a solar reflective performance consisting of synthetic resin containing a different titanium oxide particles of at least two types of particle size,
Two kinds of titanium oxide particles having different particle diameters are respectively titanium oxide A and titanium oxide B. The weight average particle diameter of titanium oxide A is φ = 0.15 to 0.35 μm, and the standard deviation in the weight average particle diameter is ρ = 0.1 or less, the weight average particle diameter of titanium oxide B is φ = 0.7 to 1.3 μm, the standard deviation in the weight average particle diameter is ρ = 0.2 or more,
The compounding ratio (weight ratio) of titanium oxide A and titanium oxide B is 3: 1 to 10: 1, and the total addition amount of titanium oxide A and titanium oxide B is based on 100 parts by weight of the synthetic resin. 10 to 30 parts by weight,
It has a thickness of 75Myuemu～500myuemu, and gist a sheet having a solar reflective performance, wherein the reflectance over the entire wavelength range of the wavelength 500~1500nm is 75% or.
At this time, over TMG, polychlorinated vinyl resin, acrylic resin, polyester resin, polyolefin resin, preferably contains at least one resin selected from urethane resin.

  The sheet of the present invention has a reflectivity of 75% or more and an absorptivity of 10% or less over the entire wavelength region of a wavelength of 500 to 1500 nm, preferably a reflectivity of a wavelength of 700 to 1500 nm is 80% or more and an absorptance of 5% or less. This effectively reflects light that contributes to heat generation in sunlight, and prevents an increase in temperature due to light inside the structure due to this sheet, and also prevents excessive heating of the sheet itself. It is to suppress.

In order to obtain the above reflection / absorption characteristics, the present invention uses at least two types of titanium oxide fine particles having different particle diameters.
According to the studies of the present inventors, by controlling the particle size of the titanium oxide fine particles, it is possible to effectively reflect light differently wavelengths, a relatively monodisperse, and the average particle size phi = 0.25 [mu] m approximately smaller particles effectively reflect light of the region close to the visible light of approximately 400-80 0 nm, on the other hand, a relatively size distribution is wide, and an average particle diameter of phi = 1.0 .mu.m It has been confirmed that the larger particles reflect light of a wavelength in the near infrared region of about 800 to 1500 nm particularly effectively.

The present invention includes at least the above-mentioned two kinds of particle diameters, titanium oxide fine particles having different particle size distributions, specifically, a smaller titanium oxide A having an average particle diameter φ = 0.15 to 0.35 μm, and an average particle diameter φ. = By blending a large titanium oxide B of 0.7 to 1.3 μm into the synthetic resin that is the base of the sheet, it has superior reflection performance in a wide range of wavelengths of sunlight compared to the case where each is blended alone. A sheet that develops is obtained.
The particle size distribution of the titanium oxide A is such that the standard deviation in the weight average particle diameter is ρ = 0.1 or less, and that of the titanium oxide B is that the standard deviation is ρ = 0.2 or more. It is preferable for effectively expressing the action.

The blending ratio of the titanium oxide fine particles A and the titanium oxide fine particles B is about the same as the case of the large titanium oxide fine particles B alone if the amount of the small titanium oxide fine particles A is too small compared to the amount of the large titanium oxide fine particles B. Only the reflection performance can be obtained, and if there are too many titanium oxide fine particles A, only the reflection performance comparable to that in the case of the titanium oxide fine particles A alone can be obtained.
Accordingly, in the present invention, the titanium oxide fine particles A: titanium oxide fine particles B are used in a mixing ratio (weight ratio) of 3: 1 to 10: 1.

  If the total addition amount of the titanium oxide fine particles A and the titanium oxide fine particles B in the above blending ratio is too small, the target solar light reflecting performance cannot be obtained, and if it is too large, this effect is saturated. In addition, since there is a tendency to cause a problem in moldability to a sheet, in the present invention, the amount is 10 to 30 parts by weight, preferably 10 to 20 parts by weight, with respect to 100 parts by weight of the synthetic resin.

  In the present invention, a general rutile type is used as the titanium oxide fine particles A and B.

The synthetic resin containing at least two types of titanium oxide fine particles A and B is at least one selected from the group consisting of polyvinyl chloride resin, acrylic resin, polyester resin, polyolefin resin, and urethane resin. Resin is used.
Among these resins, polyvinyl chloride resins, acrylic resins, and urethane resins that are fluid (= paste, solvent-soluble, water-dispersed, and oligomer reaction curable) that exhibit fluidity at room temperature are particularly suitable. In particular, polyvinyl chloride resin is most suitable in terms of sheet processability (sewing properties, welder processability) and weather resistance.

  Examples of the polyvinyl chloride resin include a homopolymer of a polyvinyl chloride monomer, and a copolymer of a polyvinyl chloride monomer and a monomer copolymerizable with a polyvinyl chloride monomer such as a vinyl acetate monomer and an acrylonitrile monomer. The emulsion polymerization method (emulsion polymerization method) which can be used and exhibits a paste-like plastisol state when a plasticizer is blended is particularly preferably used. In addition, a micro suspension polymerization method, a soap-free emulsion polymerization method, a suspension polymerization method. Those polymerized by (suspension polymerization) or the like are also preferably used.

  In addition, the urethane resin can be a solution-polymerized polyurethane resin, and is preferably a liquid that becomes liquid at room temperature by mixing a solvent. If necessary, a sheet is obtained by blending a crosslinking agent and a curing agent. The physical properties can be improved.

Sheet, the above synthetic resins of the present invention, at least two types of titanium oxide emissions A described above, blended with B, which is obtained by forming into a sheet by various methods, the thickness of the sheet is too thin if, it is not possible to obtain the reflection performance of the solar light for the purpose, be too thick not only the effect is saturated, to lower handling properties and increased weight, and 75μ m ~500μm.

Moreover, in this invention, various additives can be mix | blended with said mixing | blending as needed.
For example, when a polyvinyl chloride resin is used as the base material of the sheet, an ordinary plasticizer or stabilizer, an ultraviolet absorber such as a hindered amine compound, a benzotriazole compound, or a benzothiazole compound, or an antioxidant is blended. In order to improve the workability, various additives such as a thickener and a thickener can be added.
Moreover, fillers, such as a calcium carbonate, aluminum hydroxide, a glass balloon, a shirasu balloon, a glass bead, can also be mix | blended as needed.

The mixing of the above components is carried out by weighing each component and mixing it homogeneously with a mixing stirrer such as a dissolver mixer.
If necessary, it can be filtered for the purpose of removing undispersed matter, or degassed under reduced pressure to remove bubbles.

  Various methods can be adopted as a method for forming a sheet in the present invention. When a polyvinyl chloride resin paste plastisol is used as a base resin, it is coated on a paper or film having releasability to a specified thickness by an appropriate method. A method of peeling from paper or film after solidification by heating is preferred.

Also, when a urethane resin is used as the base resin, it is preferable to coat the paper or film having releasability as described above, and peel it after heating and solidifying.
In this case, a solid sheet can be formed by blending a crosslinking agent, a curing agent and the like.

In addition, an antifouling layer or a protective layer can be provided on the surface of the sheet of the present invention.
This antifouling layer can be formed by applying an antifouling paint composed of solvent-based, water-based, or UV-curable paints, and the protective layer can form various hard coat layers and surface slipping layers. By doing so, it can be formed.

The sheet of the present invention may be laminated with a fibrous base material such as a knitted fabric, a woven fabric, or a non-woven fabric as necessary.
Fibrous base material to sheet may be laminated with an adhesive or the like of the present invention may be laminated in a manner to coated sheets of the present invention the fibrous substrate.
Furthermore, the sheet of the present invention may be arranged on one side of the fiber base material, and a general resin sheet may be laminated on the other side to form a tarpaulin.
Furthermore, after impregnating the fibrous base material with the resin composition in the present invention, it can be solidified to form a layer, that is, a sheet of the present invention.
Thus, by providing a fibrous base material, the tear strength and tensile strength of the sheet itself of the present invention can be increased, and the durability during use and the dimensional stability during construction can be further improved.

  According to the present invention, at least two types of titanium oxide fine particles having different particle states, specifically, those having a relatively narrow distribution and a fine particle size, and those having a relatively wide distribution and a large particle size, By using in combination at a specific ratio, it is possible to obtain a sheet having excellent reflection performance over the entire wavelength range of 500 to 1500 nm.

[Preparation of sheet-like paste plastisol]
For sheet molding, a paste-like plastisol was prepared by uniformly mixing a plasticizer, a heat stabilizer, and titanium oxide fine particles with emulsion-polymerized polyvinyl chloride at a ratio shown in Table 1 using a dissolver mixer.

The meanings of the words in Table 1 are as follows.
Titanium oxide total amount: parts by weight,
Titanium oxide ratio: Ratio of titanium oxide A and titanium oxide B, or ratio of titanium oxide A and titanium oxide C Polyvinyl chloride resin: Product name “PQHPN” manufactured by Shin Daiichi Vinyl
Plasticizer: isononyl phthalate (manufactured by Sekisui Chemical Co., Ltd.)
Stabilizer: Product name "AC183" manufactured by Asahi Denka Kogyo Co., Ltd.
Titanium oxide A: Titanium oxide white pigment, average particle size : φ = 0.25μm, standard deviation: ρ = 0.071, trade name “JR-600A” manufactured by Teika
Titanium oxide B: Titanium oxide white pigment, average particle size : φ = 1.03 μm, standard deviation: ρ = 0.34, trade name “JR-1000” manufactured by Teica
Titanium oxide C: Titanium oxide white pigment, average particle size : φ = 0.29μm, standard deviation: ρ = 0.12, trade name “JR-805” manufactured by Teica

[Preparation of test sheet]
Test sheets having the forms shown in Table 2 with the formulation shown in Table 1 were prepared in the manner described below, the reflectance was measured in the manner described below for these sheets, and the results are also shown in Table 2.

[Guidelines for forming test sheets]
The prepared paste-like plastisol was coated on a release paper to a predetermined thickness by a knife coating method, heated at 140 ° C. for 2 minutes, and then heated at 195 ° C. for 3 minutes. Thereafter, it was cooled to release the release paper, and a sheet was prepared.

[Reflectance measurement method]
The reflectance is a spectrophotometer (V-570 manufactured by JASCO Corporation), a standard white plate (fluororesin other porous body) is taken as 100% reflectance, and the spectrum is in the range of 500 to 1500 nm. The reflectance was measured.
Furthermore, the solar reflectance is a value calculated by taking into account the intensity of each wavelength of sunlight using JIS A5759 Attached Table 3. In the present invention, the solar reflectance is calculated at a wavelength of 500 to 1500 nm. did.

The meanings of the words in Table 2 are as follows.
Sheet name: “ratio” is “comparative example”
Formula: "Real (1)", "Real (2)" ... "Ratio (1)", "Ratio (2)" ... are "Example 1", "Example 2", respectively. -"Comparative example 1", "Comparative example 2" ...
Unit: sheet thickness; mm, reflectance:%
Reflectance (minimum), (maximum): Minimum and maximum reflectance of solar radiation when light having a wavelength of 500 to 1500 nm is irradiated by spectroscopic analysis: Solar reflectance in a wavelength range of 500 to 1500 nm

When the sheet of the present invention is used for a sheet-like structure such as a tent, the internal temperature rise due to sunlight is suppressed, and further, the temperature rise of the sheet surface is also suppressed, so that deterioration due to long-term use is also reduced. , Military tents, temporary tents for disasters, tent warehouses used for a long time semi-permanently, truck hoods, etc. It is effective when used in tropical or desert climates.

Claims (2)

A sheet having a solar reflective performance consisting of synthetic resin containing a different titanium oxide particles of at least two types of particle size,
Two kinds of titanium oxide particles having different particle diameters are respectively titanium oxide A and titanium oxide B. The weight average particle diameter of titanium oxide A is φ = 0.15 to 0.35 μm, and the standard deviation in the weight average particle diameter is ρ = 0.1 or less, the weight average particle diameter of titanium oxide B is φ = 0.7 to 1.3 μm, the standard deviation in the weight average particle diameter is ρ = 0.2 or more,
The compounding ratio (weight ratio) of titanium oxide A and titanium oxide B is 3: 1 to 10: 1, and the total addition amount of titanium oxide A and titanium oxide B is based on 100 parts by weight of the synthetic resin. 10 to 30 parts by weight,
It has a thickness of 75Myuemu～500myuemu, sheet having a solar reflective performance, wherein the reflectance over the entire wavelength range of the wavelength 500~1500nm is 75% or. The sheet, polychlorinated vinyl resin, acrylic resin, polyester resin, polyolefin resin, sunlight reflecting performance according to claim 1, characterized in that it comprises at least one resin selected from urethane resin Having a sheet.