JP4007497B2

JP4007497B2 - Light-fever underwear

Info

Publication number: JP4007497B2
Application number: JP2002313204A
Authority: JP
Inventors: 昌一平野; 和人尾崎; 美也由井; 伸午秋枝; 忍田畑
Original assignee: Gunze Ltd
Current assignee: Gunze Ltd
Priority date: 2002-10-28
Filing date: 2002-10-28
Publication date: 2007-11-14
Anticipated expiration: 2022-10-28
Also published as: JP2004149931A

Description

【０００１】
【発明の属する技術分野】
本発明は、上着を着用した場合でも顕著な暖房効果が得られ、かつ、実質的な風合いの悪化の少ない光発熱性肌着に関する。
【０００２】
【従来の技術】
従来、繊維製品の保温性を高める方法としては、生地を厚くする、目を細かくする等の方法で生地の断熱性を高め、内部の熱を逃さないようにする方法が一般的であった。また、繊維の内部を中空にして空気の層を形成させることにより体温が外に逃げるのを防ぐ繊維製品も開発されている。これらの方法は、いずれも着用時に体温が外部に逃げるのを防ぐことによる保温効果を利用するものであり、得られる保温性は充分なものではなかった。
【０００３】
これに対して、一方、太陽光を吸収し熱に変えて着衣内部に放散させることで蓄熱性を得ようとする方法が試みられている。地球上に到達する太陽光の放射エネルギーの分布は０．５μｍのいわゆる近赤外線付近にピークがあり、０．３〜２．０μｍの波長領域内に全エネルギー量の９５％が集中していることから、近赤外線を熱エネルギーとして効率的に活用できるような光発熱性繊維製品を用いれば、衣類に暖房機能を付与することができる。
【０００４】
このような光発熱性繊維製品としては、例えば、炭化ジルコニウム等の近赤外線を吸収し熱に変換する無機物質を練り込んだ繊維製品が提案されている。また、特許文献１、２には、アミノ系化合物からなる赤外線吸収色素をバインダー樹脂を用いて繊維の表面に付着させた繊維製品が、特許文献３にはインダスレン染料をポリアミド繊維に付着させた繊維製品が開示されている。
【０００５】
光発熱性繊維製品を用いて衣類に暖房効果を付与する場合、最も効率よく暖房効果が体感されるのは、肌に直接接する肌着として用いる場合である。しかしながら、肌着上にシャツ等の上着を着用した場合、透過性に劣る近赤外線が肌着にまで達するエネルギー量が減少し、充分な暖房効果を得ることができない。これを補うために大量の近赤外線を吸収し熱に変換する物質を配合しようとしても、炭化ジルコニウム等の無機物質を練り込んだり、赤外線吸収色素を付着させたりすると生地の風合いが悪化し肌触りが悪くなることから、一定量以上を配合すると肌着としては用いることができなくなるという問題があった。
【０００６】
【特許文献１】
特開平８−００３８７０号公報
【特許文献２】
特開平９−２５５８９０号公報
【特許文献３】
特開平１１−１３１３７６号公報
【０００７】
【発明が解決しようとする課題】
本発明は、上記現状に鑑み、上着を着用した場合でも顕著な暖房効果が得られ、かつ、実質的な風合いの悪化の少ない光発熱性肌着を提供することを目的とするものである。
【０００８】
【課題を解決するための手段】
本発明は、近赤外線を吸収し熱に変換する物質を含有する光発熱性肌着であって、前記近赤外線を吸収し熱に変換する物質は、肌に接する側の面よりも肌に接しない側の面により多く含有されている光発熱性肌着である。
以下に本発明を詳述する。
【０００９】
本発明の光発熱性肌着は、近赤外線を吸収し熱に変換する物質を含有する。
上記近赤外線を吸収し熱に変換する物質としては特に限定されないが、例えば、炭化ジルコニウム、酸化スズ及び金属錯体化合物からなる群より選択される少なくとも１種が好適に用いられる。上記金属錯体化合物としては、例えば、アンチモン固溶酸化スズ、炭化ハフニウム、アンソラキノン系化合物、ナフタロシアニン化合物等が挙げられる。
【００１０】
本発明の光発熱性肌着に用いる繊維生地材料としては特に限定されず、天然繊維、半合成繊維、合成繊維等のいずれの繊維でもよい。上記天然繊維としては特に限定されず、例えば、綿、麻、亜麻、羊毛、絹等が挙げられる。上記半合成繊維としては特に限定されず、例えば、レーヨン、ポリノジック、テンセル等が挙げられる。上記合成繊維としては特に限定されず、例えば、ナイロン等のポリアミド系、ポリエステル系、ポリオレフィン系、ポリウレタン系等の繊維が挙げられる。これらは、それぞれ単独で用いられてもよいし、混紡又は混織されて用いられてもよい。
【００１１】
上記近赤外線を吸収し熱に変換する物質は、肌に接する側の面よりも肌に接しない側の面により多く含有される。これにより、上着を着用することにより肌着に到達する近赤外線のエネルギー量が減少しても、上記近赤外線を吸収し熱に変換する物質の多くが外側にあることから、効率的に熱に変換して優れた暖房効果を発現することができる。一方、肌に接する側の面の含有量を抑えることにより、実質的な肌着の風合いの悪化を最小限に抑えることができる。
【００１２】
上記近赤外線を吸収し熱に変換する物質を上記繊維生地に含有させる方法としては特に限定されず、例えば、上記近赤外線を吸収し熱に変換する物質を適当なバインダー物質を含有する水溶液中に懸濁し、この懸濁液中に繊維生地を浸漬した後、乾燥、熱処理を行うことにより固定する方法等が挙げられる。
【００１３】
本発明の光発熱性肌着を製造する方法としては特に限定されないが、例えば、繊維生地に水分を含浸させる工程１と、水分を含有させた繊維生地を、絞り率２０〜２００％に絞って過剰な水分を除去する工程２と、過剰な水分を除去した繊維生地の一方の面を、近赤外線を吸収し熱に変換する物質がバインダー物質を含有する水溶液中に懸濁した懸濁液中に接触させた後、絞り率４０〜３００％に絞る工程３と、近赤外線を吸収し熱に変換する物質が付着した繊維生地を乾燥及び熱処理する工程４とを有する方法等が好適である。
【００１４】
上記方法では、工程１において繊維生地に水分を含浸させた後、工程２において絞り率２０〜２００％に絞って過剰な水分を除去する。好ましくは、絞り率８０〜１２０％に絞って過剰な水分を除去する。この段階で繊維生地は水分をある程度含有している状態にある。
次いで、工程３において、過剰な水分を除去した繊維生地の一方の面を、上記近赤外線を吸収し熱に変換する物質をバインダー物質を含有する水溶液中に懸濁させた懸濁液中に接触させた後、絞り率４０〜３００％に絞る。ここで、繊維生地は水分をある程度含有している状態にあったことから、懸濁液に接触させても急速に近赤外線を吸収し熱に変換する物質を吸い上げることがなく、絞り率４０〜３００％に絞れば、一方の面にのみ重点的に近赤外線を吸収し熱に変換する物質を付着させることができる。好ましくは、絞り率８０〜１６０％に絞る。
なお、本明細書において絞り率とは、繊維生地の重量に対する繊維生地に付着している液体の重量の割合を意味し、例えば、絞り率１００％とは、繊維生地１００ｇに対して１００ｇの液体が付着している状態を意味する。
【００１５】
上記繊維生地に付着させる近赤外線を吸収し熱に変換する物質の量は、上記懸濁液中の近赤外線を吸収し熱に変換する物質の濃度、及び、繊維生地を上記懸濁液に接触させる時間により調整することができる。上記懸濁液中における近赤外線を吸収し熱に変換する物質の濃度としては特に限定されないが、５ｇ／Ｌ以上であることが好ましい。５ｇ／Ｌ未満であると、必要な量の近赤外線を吸収し熱に変換する物質を繊維生地に付着させることができないことがある。上記繊維生地を上記懸濁液に接触させる時間としては上記懸濁液中における近赤外線を吸収し熱に変換する物質の濃度により適宜決定されるものであるが、１０秒以下であることが好ましい。１０秒を超えると、上記懸濁液に接触させた側とは反対の面にまで上記懸濁液が浸透し、一方の面に重点的に近赤外線を吸収し熱に変換する物質を付着させることができないことがある。
また、上記バインダー物質としては特に限定されず、例えば、通常綿に用いられるシリコン系バインダー等が挙げられる。
最後に、工程４において乾燥及び熱処理を行い、近赤外線を吸収し熱に変換する物質を繊維生地に固定する。
【００１６】
このようにして得た一方の面にのみ重点的に近赤外線を吸収し熱に変換する物質を含有する繊維生地を用い、近赤外線を吸収し熱に変換する物質を重点的に含有する側の面が肌に接しない側になるようにして、通常の方法により縫製することにより本発明の光発熱性肌着を作製することができる。
このような本発明の光発熱性肌着を製造する方法もまた、本発明の１つである。
【００１７】
本発明の光発熱性肌着は、肌に接しない側の面に近赤外線を吸収し熱に変換する物質を重点的に含有することにより、上着を着用することにより肌着に到達する近赤外線のエネルギー量が減少しても、効率的に熱に変換して優れた暖房効果を発現することができ、かつ、肌に接する側の面の含有量を抑えられることから実質的な風合いの悪化を最小限に抑えることができる。
【００１８】
【実施例】
以下に実施例を掲げて本発明を更に詳しく説明するが、本発明はこれら実施例のみに限定されるものではない。
【００１９】
（実施例１）
綿１００％メリヤス漂白後生地を、水に浸漬し、パッダーを用いて絞り率８０％で絞った。この生地の一方の面を、酸化スズ微粒子０．５％をバインダー（バインテックスＳ２００Ｌ：大和化学工業社製）１％を含む水溶液中に懸濁させた懸濁液中に０．５秒間接触させた後、直ちにパッダーを用いて絞り率１００％で絞った。その後、１００℃５分間乾燥し、更に、１４０℃３分間熱処理を行い、光発熱性肌着用の生地を作製した。
【００２０】
（比較例１）
綿１００％メリヤス漂白後生地を、酸化スズ微粒子０．５％をバインダー（バインテックスＳ２００Ｌ：大和化学工業社製）１％を含む水溶液中に懸濁させた懸濁液中に浸漬した後、１００℃５分間乾燥し、更に、１４０℃３分間熱処理を行い、光発熱性肌着用の生地を作製した。
【００２１】
（比較例２）
未加工品として綿１００％メリヤス漂白後生地を用いた。
【００２２】
実施例１及び比較例１、２で得られた肌着用の生地について、下記の評価を行った。
【００２３】
（１）生地上の酸化スズ付着量の評価
蛍光エックス線分析装置を用いてＳｎ元素量を測定することにより、生地の表面（酸化スズを作用させた面）、裏面（酸化スズを作用させなかった面）及び生地全体の酸化スズの付着量を測定した。
結果を表１に示した。
【００２４】
【表１】

【００２５】
（２）光発熱機能の評価
生地を表を上にして、その上に白色綿５０％、ポリエステル５０％からなるワイシャツをかけた。生地との距離が５０ｃｍとなる位置に出力５００Ｗのレフランプを置き、ワイシャツ越しに生地温度が４０℃程度以下（秋冬太陽光レベル）になるように光を照射した。照射開始から１０分後に消灯し、２０分後まで生地の裏面に貼り付けた温度センサーにより生地温度を測定した。
この間の温度変化を図１に示した。
【００２６】
表１より、実施例１で得られた光発熱性生地と比較例１で得られた光発熱性生地とでは、全体としてはほぼ同じ量の酸化スズが付着していたものの、比較例１では表面（酸化スズを作用させた面）でも裏面（酸化スズを作用させなかった面）でもほぼ同量であったのに対して、実施例１では裏面に比べて表面に多くの酸化スズが付着していた。
また、図１より、実施例１及び比較例１で得られた光発熱性生地ともに、未処理の生地に比べて生地温度が高かったが、特に実施例１で得られた光発熱性生地は比較例１で得られた光発熱性生地よりも更に高い暖房効果が得られた。
【００２７】
【発明の効果】
本発明は、上着を着用した場合でも顕著な暖房効果が得られ、かつ、実質的な風合いの悪化の少ない光発熱性肌着に関する。
【図面の簡単な説明】
【図１】実施例で行った光発熱機能の評価における各生地の温度の変化を示す図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light-generating underwear that can provide a remarkable heating effect even when an outerwear is worn, and has little substantial deterioration in texture.
[0002]
[Prior art]
Conventionally, as a method for increasing the heat retaining property of a textile product, there has been a general method of increasing the heat insulating property of the fabric by increasing the thickness of the fabric or making the eyes finer so as not to let the internal heat escape. In addition, fiber products have been developed that prevent body temperature from escaping by hollowing the inside of the fiber to form an air layer. All of these methods utilize the heat retention effect by preventing the body temperature from escaping to the outside when worn, and the heat retention obtained is not sufficient.
[0003]
On the other hand, a method has been attempted in which heat storage properties are obtained by absorbing sunlight, converting it into heat, and dissipating it into the clothing. The distribution of the radiant energy of sunlight that reaches the earth has a peak in the vicinity of the so-called near infrared ray of 0.5 μm, and 95% of the total energy amount is concentrated in the wavelength region of 0.3 to 2.0 μm. from the use of the light pyrogenic textile that allows efficient use of near-infrared as thermal energy, can be imparted to heating function to the garment.
[0004]
As such a light exothermic fiber product, for example, a fiber product in which an inorganic substance that absorbs near infrared rays such as zirconium carbide and converts it into heat has been proposed. Patent Documents 1 and 2 describe a fiber product in which an infrared-absorbing dye composed of an amino compound is attached to a fiber surface using a binder resin, and Patent Document 3 includes an indanthrene dye attached to a polyamide fiber. A textile product is disclosed.
[0005]
When a heating effect is imparted to clothing using a photo exothermic fiber product, the heating effect is most efficiently experienced when it is used as an underwear that is in direct contact with the skin. However, when an outerwear such as a shirt is worn on the underwear, the amount of energy that the near-infrared rays having poor permeability reach the underwear is reduced, and a sufficient heating effect cannot be obtained. To make up for this, even if you try to add a substance that absorbs a large amount of near infrared rays and converts it into heat, if you knead an inorganic substance such as zirconium carbide or attach an infrared absorbing dye, the texture of the fabric will deteriorate and the touch will be felt. Since it worsens, there existed a problem that it became impossible to use as underwear when a fixed amount or more was mix | blended.
[0006]
[Patent Document 1]
JP-A-8-003870 [Patent Document 2]
JP-A-9-255890 [Patent Document 3]
JP-A-11-131376
[Problems to be solved by the invention]
In view of the above situation, the present invention has an object to provide a photo-exothermic undergarment that has a remarkable heating effect even when a jacket is worn, and that is substantially less deteriorated in texture.
[0008]
[Means for Solving the Problems]
The present invention is a photothermal underwear containing a substance that absorbs near-infrared light and converts it into heat, and the substance that absorbs near-infrared light and converts it into heat is less in contact with the skin than the surface in contact with the skin. It is a photothermal underwear that is contained more on the side surface.
The present invention is described in detail below.
[0009]
The photothermal underwear of the present invention contains a substance that absorbs near infrared rays and converts it into heat.
The substance that absorbs near-infrared rays and converts it into heat is not particularly limited. For example, at least one selected from the group consisting of zirconium carbide, tin oxide, and metal complex compounds is preferably used. Examples of the metal complex compound include antimony solid solution tin oxide, hafnium carbide, anthoraquinone compounds, naphthalocyanine compounds, and the like.
[0010]
It does not specifically limit as fiber fabric material used for the photo exothermic underwear of this invention, Any fiber, such as a natural fiber, a semisynthetic fiber, a synthetic fiber, may be sufficient. It does not specifically limit as said natural fiber, For example, cotton, hemp, flax, wool, silk etc. are mentioned. The semisynthetic fiber is not particularly limited, and examples thereof include rayon, polynosic, and tencel. The synthetic fiber is not particularly limited, and examples thereof include polyamide-based fibers such as nylon, polyester-based, polyolefin-based, and polyurethane-based fibers. Each of these may be used alone, or may be used after being blended or woven.
[0011]
The substance that absorbs near-infrared rays and converts it into heat is contained more in the surface that does not contact the skin than the surface that contacts the skin. As a result, even if the amount of near-infrared energy that reaches the underwear is reduced by wearing an outerwear, many of the substances that absorb near-infrared and convert it into heat are on the outside, so that heat can be efficiently absorbed. It can be converted to exhibit an excellent heating effect. On the other hand, by suppressing the content of the surface in contact with the skin, substantial deterioration of the texture of the underwear can be minimized.
[0012]
There is no particular limitation on the method for causing the fiber fabric to contain a substance that absorbs near infrared rays and converts it into heat. For example, a substance that absorbs near infrared rays and converts it into heat in an aqueous solution containing an appropriate binder substance. Examples thereof include a method of suspending, immersing the fiber dough in the suspension, and then fixing by performing drying and heat treatment.
[0013]
Although it does not specifically limit as a method to manufacture the photo exothermic underwear of this invention, For example, the fiber fabric impregnated with the water | moisture content of the fiber fabric and the fiber fabric containing the water | moisture content are restrict | squeezed to 20 to 200%, and it is excessive. Step 2 for removing excessive moisture and one side of the fiber fabric from which excess moisture has been removed are suspended in an aqueous solution in which a substance that absorbs near infrared rays and converts it into heat is suspended in an aqueous solution containing a binder substance. A method including the step 3 of reducing the drawing ratio to 40 to 300% after the contact and the step 4 of drying and heat-treating the fiber fabric to which a substance that absorbs near infrared rays and converts it into heat is suitable.
[0014]
In the above method, after impregnating the fiber dough with water in Step 1, excess water is removed by squeezing to 20 to 200% in Step 2. Preferably, excessive water is removed by reducing the drawing rate to 80 to 120%. At this stage, the fiber fabric is in a state containing some moisture.
Next, in step 3, one side of the fiber fabric from which excess moisture has been removed is brought into contact with a suspension obtained by suspending a substance that absorbs near infrared rays and converts it into heat in an aqueous solution containing a binder substance. Then, the aperture ratio is reduced to 40 to 300%. Here, since the fiber dough was in a state of containing moisture to some extent, even if it was brought into contact with the suspension, it did not rapidly absorb a substance that absorbs near infrared rays and converts it into heat, and a drawing rate of 40 to If it is reduced to 300%, a substance that absorbs near-infrared rays and converts it into heat can be attached to only one surface. Preferably, the aperture ratio is reduced to 80 to 160%.
In this specification, the squeezing rate means the ratio of the weight of the liquid adhering to the fiber fabric to the weight of the fiber fabric. For example, 100% squeezing rate means 100 g of liquid per 100 g of the fiber fabric. Means the state of adhering.
[0015]
The amount of the substance that absorbs near-infrared light that is attached to the fiber fabric and converts it into heat is the concentration of the substance that absorbs near-infrared light and converts it into heat in the suspension, and the fiber fabric contacts the suspension. It can be adjusted according to the time to be used. Although it does not specifically limit as a density | concentration of the substance which absorbs the near infrared rays in the said suspension, and converts it into heat, It is preferable that it is 5 g / L or more. If it is less than 5 g / L, a substance that absorbs a necessary amount of near infrared rays and converts it into heat may not be attached to the fiber fabric. The time for bringing the fiber fabric into contact with the suspension is appropriately determined depending on the concentration of the substance that absorbs near-infrared rays and converts it into heat in the suspension, but is preferably 10 seconds or less. . When it exceeds 10 seconds, the suspension penetrates to the surface opposite to the side in contact with the suspension, and a substance that absorbs near infrared rays and converts it into heat is attached to one surface. There are times when you can't.
Moreover, it does not specifically limit as said binder substance, For example, the silicon-type binder etc. which are normally used for cotton are mentioned.
Finally, drying and heat treatment are performed in step 4, and a substance that absorbs near-infrared rays and converts it into heat is fixed to the fiber fabric.
[0016]
The fiber fabric containing a substance that absorbs near-infrared light and converts it into heat mainly on one side obtained in this way, on the side that mainly contains a substance that absorbs near-infrared light and converts it into heat The photo exothermic underwear of the present invention can be produced by sewing by a normal method so that the surface is not in contact with the skin.
Such a method for producing the photothermal underwear of the present invention is also one of the present invention.
[0017]
The photogenic underwear of the present invention contains near-infrared-absorbing substance that absorbs near-infrared light and converts it into heat on the surface that does not come into contact with the skin. Even if the amount of energy is reduced, it can be efficiently converted into heat and an excellent heating effect can be exhibited, and the content on the surface in contact with the skin can be suppressed, resulting in a substantial deterioration in texture. Can be minimized.
[0018]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
[0019]
Example 1
The fabric after bleaching 100% cotton knitted fabric was immersed in water and squeezed with a padder at a squeezing rate of 80%. One side of this dough was brought into contact with a suspension of 0.5% tin oxide fine particles suspended in an aqueous solution containing 1% binder (Vinetex S200L: manufactured by Daiwa Chemical Industry Co., Ltd.) for 0.5 seconds. Immediately after that, the pad was squeezed at a drawing rate of 100%. Then, it dried at 100 degreeC for 5 minute (s), and also heat-processed at 140 degreeC for 3 minute (s), and produced the fabric for photo exothermic skin wearing.
[0020]
(Comparative Example 1)
100% cotton knitted fabric after being bleached is immersed in a suspension in which 0.5% tin oxide fine particles are suspended in an aqueous solution containing 1% binder (Vinetex S200L: manufactured by Daiwa Chemical Industry Co., Ltd.). Drying was performed at 5 ° C. for 5 minutes, and further heat treatment was performed at 140 ° C. for 3 minutes to prepare a fabric for photo exothermic skin wearing.
[0021]
(Comparative Example 2)
100% cotton knitted fabric after bleaching was used as a raw product.
[0022]
The following evaluations were performed on the underwear fabrics obtained in Example 1 and Comparative Examples 1 and 2.
[0023]
(1) Evaluation of adhesion amount of tin oxide on fabric The surface of the fabric (surface on which tin oxide was applied) and the back surface (on which tin oxide was not applied) were measured by measuring the amount of Sn element using a fluorescent X-ray analyzer. Surface) and the amount of tin oxide deposited on the entire fabric.
The results are shown in Table 1.
[0024]
[Table 1]

[0025]
(2) Evaluation of light-generating function The fabric was face up, and a shirt composed of 50% white cotton and 50% polyester was put on it. A 500 W output reflex lamp was placed at a position where the distance to the fabric was 50 cm, and light was irradiated through the shirt so that the fabric temperature was about 40 ° C. or less (autumn / winter sunlight level). The light was turned off 10 minutes after the start of irradiation, and the temperature of the cloth was measured with a temperature sensor attached to the back of the cloth until 20 minutes later.
The temperature change during this period is shown in FIG.
[0026]
From Table 1, although the photo exothermic fabric obtained in Example 1 and the photo exothermic fabric obtained in Comparative Example 1 had almost the same amount of tin oxide adhered as a whole, in Comparative Example 1, The amount of tin oxide adhered to the front surface compared to the back surface in Example 1, whereas the surface (the surface on which tin oxide was applied) and the back surface (the surface on which tin oxide was not applied) were almost the same amount. Was.
Moreover, from FIG. 1, although the photoexothermic fabric obtained in Example 1 and Comparative Example 1 had a higher fabric temperature than the untreated fabric, the photoexothermic fabric obtained in Example 1 in particular was A heating effect higher than that of the photo-exothermic fabric obtained in Comparative Example 1 was obtained.
[0027]
【The invention's effect】
The present invention relates to a light-generating underwear that can provide a remarkable heating effect even when an outerwear is worn, and has little substantial deterioration in texture.
[Brief description of the drawings]
FIG. 1 is a diagram showing changes in the temperature of each fabric in the evaluation of the light heating function performed in Examples.

Claims

A light-generating underwear containing a substance that absorbs near-infrared light and converts it into heat, wherein the substance that absorbs near-infrared light and converts it into heat is formed by a surface that is not in contact with the skin rather than a surface that is in contact with the skin. A method for producing a photogenic underwear that contains a large amount ,
Step 1 of impregnating the fiber fabric with moisture,
Step 2 of removing excess moisture by squeezing the fiber fabric containing moisture to a squeezing rate of 20 to 200%;
One surface of the fiber fabric from which excessive moisture has been removed is brought into contact with a suspension in which a substance that absorbs near infrared rays and converts it into heat is suspended in an aqueous solution containing a binder substance, and then a drawing ratio of 40 is obtained. Step 3 to narrow down to ~ 300%,
And a step 4 of drying and heat-treating the fiber fabric to which the substance that absorbs near infrared rays and converts it into heat is attached.