JP4193074B2 - Pyroelectric materials - Google Patents

Description

【００６２】
次に、上記実施例１〜３並びに比較例１及び２の各サンプルについて、その焦電性能を測定した。測定は、図７に示すように、サンプル１１の表裏両面と電圧計１２とを電気的に接続し、これを断熱材よりなる基台１０上に置き、このサンプル１１上５００ｍｍの高さの金網１３上に１００°Ｃに熱した金属板１４を置き、その時の最大電圧を電圧計１２により測定し、この測定値を表２に示した。
【００６３】
尚、比較のため、上記実施例１〜３、並びに比較例１及び２の各サンプルについてポーリング処理（分極処理）を行い、これらについて同様に焦電性能を測定した。尚、ポーリング処理は、各サンプルを１００°Ｃのオイルバス中で１ＫＶの直流電流を１時間印荷し、その状態のまま室温まで冷却し印荷を外すという方法で行った。
【００６４】
【表２】

【００６５】
表２から、比較例１のものが５ｍＶまたは６ｍＶと、分極の有無に拘わらず、低い値となっているのに対し、分極していない実施例１〜３のものが、約１２００から１６０ｍＶと桁外れの高い値を示した。また、ポーリング処理を行った場合の各実施例１〜３の数値についても、約１３５から１７０ｍＶと高い値を示した。また、市販の分極された比較例２のものは１１９ｍＶであり、これに比べても実施例に係るものは優れた焦電性能を有していることが解る。このような結果から、該焦電材料におけるＤＣＨＢＳＡや２ＨＰＭＭＢなどの活性成分が焦電性能の向上に大きく寄与していることが解った。
【００６６】
【発明の効果】
本発明の焦電材料は、従来の焦電材料の持つ焦電性能からは予測できない程の優れた焦電性能を有しており、しかもその製造に際し延伸、分極といった処理を必要としないので、きわめて安価である。
【００６７】
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【図面の簡単な説明】
【図１】焦電材料における双極子を示した模式図。
【図２】エネルギー（熱）が伝わったときの焦電材料における双極子の状態を示した模式図。
【図３】母材中に活性成分が配合されたときの焦電材料における双極子の状態を示した模式図。
【図４】焦電材料における誘電率（ε′）と誘電損率（ε″）との関係を示したグラフ。
【図５】実施例１〜３並びに比較例１の各焦電材料からなるフィルムを模式的に示した模式図。
【図６】比較例２の焦電材料からなるフィルムを模式的に示した模式図。
【図７】実施例１〜３、並びに比較例１及び２の各焦電材料からなるフィルムの焦電性能を測定する装置を模式的に示した模式図。
【符号の説明】
１・・・焦電材料
２・・・双極子[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pyroelectric material having an energy conversion function from heat to electricity and used for an infrared sensor or the like.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, ferroelectric materials having spontaneous polarization and a large pyroelectric coefficient have been used as pyroelectric materials. Specifically, single crystals such as triglycine sulfate (TGS) and lithium tantalate, and pyroelectric ceramics such as lead titanate (PZT), lead zirconate (PZ), and lead zirconate titanate (PZT) are widely used. It was.
[0003]
However, these pyroelectric materials have the disadvantage that they are difficult to work in a large area and are brittle, and because they require polarization treatment, they have become extremely expensive materials.
[0004]
As another pyroelectric material, there has also been proposed a pyroelectric polymer obtained by stretching a fluorine-based resin such as polyvinylidene fluoride (PVDF) and subjecting it to a polarization treatment.
[0005]
However, although this pyroelectric material is improved in brittleness, its performance is lower than that of the above-described pyroelectric ceramics, and further, treatments such as stretching and polarization are required, which is also an expensive material.
[0006]
As another pyroelectric material, a composite material combining the pyroelectric ceramics and pyroelectric polymer has also been proposed.
[0007]
However, even with this pyroelectric material, the above-mentioned drawbacks of the pyroelectric material cannot be solved.
[0008]
As a result of intensive studies on the pyroelectric material in order to eliminate the disadvantages of the conventional pyroelectric material, the present inventors have determined that the amount of dipole moment in the pyroelectric material contributes to the pyroelectric performance of the pyroelectric material. It has a deep relationship, and it has been found that the pyroelectric performance of the pyroelectric material can be dramatically improved by increasing the amount of dipole moment in the pyroelectric material .
[0009]
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[0010]
The present invention has been completed based on the above-described knowledge, and aims to provide an inexpensive pyroelectric material that does not require treatment such as stretching and polarization and that has excellent pyroelectric performance. It is.
[0011]
Another object of the present invention is to provide a pyroelectric material that exhibits good pyroelectric performance in the operating temperature range.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 includes polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polymethyl methacrylate, polystyrene, styrene-butadiene-acrylonitrile copolymer, acrylic rubber, acrylonitrile - butadiene rubbers, styrene - butadiene rubber, butadiene rubber, natural rubber, isoprene rubber, chloroprene rubber and base material made of a polymer selected from chlorine polyethylene, as an active ingredient to increase the dipole moment amount in the base material And a pyroelectric material characterized in that one or more selected from a compound having a benzothiazyl group, a compound having a benzotriazole group, and a compound having a diphenyl acrylate group were blended .
[0013]
The invention according to claim 2 is characterized in that the base material is made of a polar polymer selected from polyvinyl chloride, chlorinated polyethylene, acrylic rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, and chloroprene rubber. The electrical material was the gist.
[0014]
In the invention according to claim 3, the base material has a glass transition point in the operating temperature range, and polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polymethyl methacrylate, polystyrene, and styrene. A polymer selected from butadiene-acrylonitrile copolymer and a plasticizer selected from di-2-ethylhexyl phthalate, dibutyl phthalate, diisononyl phthalate, or acrylic rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, A pyroelectric material characterized in that it is composed of a polymer selected from butadiene rubber, natural rubber, isoprene rubber, chloroprene rubber, and chlorethylene is used .
[0015]
The gist of the invention described in claim 4 is a pyroelectric material characterized in that the active ingredient is blended at a ratio of 10 to 200 parts by weight with respect to 100 parts by weight of the base material .
[0016]
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[0017]
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[0018]
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[0019]
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[0020]
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[0021]
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[0022]
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[0023]
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[0024]
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[0025]
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[0026]
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[0027]
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[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the pyroelectric material of the present invention will be described in more detail. The pyroelectric material of the present invention is characterized in that an active ingredient that increases the amount of dipole moment in the base material is blended in the base material.
[0029]
As a base material component in this pyroelectric material, polyvinyl chloride, polyethylene, chlorinated polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polymethyl methacrylate, polyvinylidene fluoride, polyisoprene, polystyrene, styrene-butadiene-acrylonitrile Polymers such as copolymers, styrene-acrylonitrile copolymers, acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), butadiene rubber (BR), natural rubber (NR), isoprene rubber (IR), etc. Can be mentioned. Among these, polyvinyl chloride is preferable because it has good moldability and is inexpensive.
[0030]
Next, the relationship between the amount of dipole moment and pyroelectric performance in a pyroelectric material containing such a polymer as a base material component will be described. When energy (heat) is applied to the pyroelectric material, the magnitude of spontaneous polarization in the pyroelectric material changes accordingly. At this time, the surface charge that exists on the pyroelectric material surface to neutralize the spontaneous polarization cannot respond to the energy change as quickly as the above-mentioned spontaneous polarization. There is a charge corresponding to the change in spontaneous polarization. The generation of electricity accompanying this energy change is called pyroelectricity, and the material is called pyroelectric material.
[0031]
In particular, in a pyroelectric material made of a polymer such as polyvinylidene fluoride, it is known that pyroelectric performance is generated by polarization due to orientation freezing of the dipole moment of the main chain or side chain of the polymer.
[0032]
The above property is caused by energy conversion in the polarized pyroelectric material. In the process of studying the mechanism of pyroelectric performance in the pyroelectric material, the present inventors have studied the dipole in the pyroelectric material. It is discovered that energy is converted by the action of being displaced with a certain degree of freedom and then restored to its original state, resulting in an unprecedented pyroelectric performance.
[0033]
The details are shown below. FIG. 1 shows an arrangement state of the dipole 2 inside the pyroelectric material 1 before energy (heat) is transmitted. It can be said that the arrangement state of the dipole 2 is in a stable state. However, when energy (heat) is transmitted to this, the dipole 2 existing inside the pyroelectric material 1 is displaced, and each dipole 2 inside the pyroelectric material 1 is unstable as shown in FIG. Each dipole 2 tries to return to a stable state as shown in FIG.
[0034]
At this time, energy conversion occurs. It is considered that the pyroelectric performance is generated through the displacement of the dipole inside the pyroelectric material 1 and the energy conversion by the restoring action of the dipole.
[0035]
From the above-described mechanism of generating pyroelectric performance, the pyroelectric performance of the pyroelectric material 1 increases as the amount of dipole moment in the pyroelectric material 1 as shown in FIGS. 1 and 2 increases. Conceivable.
[0036]
From this, it is very useful to use a material having a large amount of dipole moment in the molecule as a base material component constituting the pyroelectric material in order to ensure higher pyroelectric performance.
[0037]
A polar polymer can be cited as an example in which the amount of dipole moment within the molecule is originally large. Specific examples of the polar polymer include polyvinyl chloride, chlorinated polyethylene, acrylic rubber (ACR), acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), and chloroprene rubber (CR). be able to.
[0038]
In addition, when the pyroelectric material of the present invention is used for applications such as sensors, the temperature during use (hereinafter referred to as the operating temperature range) is approximately in the range of −20 ° C. to 40 ° C. It is very useful to use a polymer having a glass transition point as a base material component in the temperature range of use. This is because, according to the experiments by the inventors, the pyroelectric performance is exhibited most in the vicinity of the glass transition point of the polymer.
[0039]
Specific examples of polymers having a glass transition point in the operating temperature range include polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polymethyl methacrylate, polystyrene, and styrene-butadiene-acrylonitrile copolymer. A plastic transition agent such as di-2-ethylhexyl phthalate (DOP), dibutyl phthalate (DBP), or diisononyl phthalate (DINP) is added to the polymer, and the glass transition point (Tg) is moved to the operating temperature range. Alternatively, the polymer itself has an acrylic rubber (ACR), acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), butadiene rubber (BR), natural rubber (NR) having a glass transition point (Tg) in the operating temperature range. ), Isoprene rubber (IR), chloroprene rubber (CR , And the like can be mentioned polymers such as chlorinated polyethylene.
[0040]
In selecting the base material component, in addition to the amount of dipole moment in the molecule and the operating temperature range, handleability, moldability, availability, temperature performance (heat resistance and cold resistance), weather resistance, price, etc. It is desirable to consider.
[0041]
Further, in the pyroelectric material of the present invention, the active component blended in the base material is a component that dramatically increases the amount of dipole moment of the pyroelectric material, and the amount of dipole moment of the active component itself. Although the amount of the dipole moment of the active component itself is small, or the active component itself is small, the amount of the dipole moment increases dramatically by including the active component.
[0042]
For example, the amount of dipole moment generated inside the pyroelectric material 1 when the predetermined temperature condition and the magnitude of energy are the same as shown in FIG. It will increase to 3 times or 10 times below. Along with this, the energy consumption due to the restoring action of the dipole 2 when energy is transmitted will also increase dramatically, and it is considered that pyroelectric performance far exceeding prediction will occur.
[0043]
Examples of active ingredients that lead to such action and effects include N, N-dicyclohexylbenzothiazyl-2-sulfenamide (DCHBSA), 2-mercaptobenzothiazole (MBT), dibenzothiazyl sulfide (MBTS), N- Cyclohexylbenzothiazyl-2-sulfenamide (CBS), N-tert-butylbenzothiazyl-2-sulfenamide (BBS), N-oxydiethylenebenzothiazyl-2-sulfenamide (OBS), N , A compound containing a benzothiazyl group such as N-diisopropylbenzothiazyl-2-sulfenamide (DPBS),
[0044]
2- {2'-Hydroxy-3 '-(3 ", 4", 5 ", 6" tetrahydrophthalimide in which a benzotriazole having an azole group bonded to a benzene ring is used as a mother nucleus and a phenyl group is bonded thereto. Methyl) -5'-methylphenyl} -benzotriazole (2HPMMB), 2- {2'-hydroxy-5'-methylphenyl} -benzotriazole (2HMPB), 2- {2'-hydroxy-3'-t- Such as butyl-5'-methylphenyl} -5-chlorobenzotriazole (2HBMPCB), 2- {2'-hydroxy-3 ', 5'-di-t-butylphenyl} -5-chlorobenzotriazole (2HDBPCB) A compound having a benzotriazole group,
[0045]
Alternatively, one or more selected from compounds containing a diphenyl acrylate group such as ethyl-2-cyano-3,3-di-phenyl acrylate can be given.
[0046]
As content of the above-mentioned active ingredient, the ratio of 10-200 weight part is preferable with respect to 100 weight part of base materials. For example, when the content of the active ingredient is less than 10 parts by weight, a sufficient effect of increasing the amount of dipole moment cannot be obtained. When the content of the active ingredient exceeds 200 parts by weight, the compatibility is sufficiently high. Or sufficient mechanical strength may not be obtained.
[0047]
In determining the active ingredient to be blended in the base material, in addition to the amount of dipole moment described above, the compatibility between the active ingredient and the base material component, that is, the SP value is taken into consideration, and the values are close to each other. Choose a thing.
[0048]
The amount of dipole moment varies depending on the kind of the base material component and the active component described above. Even if the same component is used, the amount of dipole moment varies depending on the temperature at which energy (heat) is transmitted. Also, the amount of dipole moment varies depending on the amount of energy (heat) transmitted. For this reason, it is desirable to appropriately select and use the base material component and the active component so that the maximum dipole moment amount is taken into consideration in consideration of the temperature at the time of application and the magnitude of energy (heat).
[0049]
Further, in addition to the active ingredient, the above-mentioned base material has a mica scale piece, a glass piece, a glass piece for the purpose of increasing the mechanical strength of the pyroelectric material and for reducing the cost of the pyroelectric material as an extender. Fillers such as fiber, carbon fiber, calcium carbonate, barite, and precipitated barium sulfate can also be filled. In this case, the filler filling amount is preferably 10 to 80% by weight. For example, when the filling amount of the filler is less than 10% by weight, the strength is not improved even if the filler is filled, and conversely, even if the filling amount of the filler exceeds 80% by weight, it cannot be actually filled. Or the strength of the pyroelectric material will be reduced.
[0050]
The pyroelectric material of the present invention comprises a blender in which the above-mentioned base material component is blended with an active ingredient and, if necessary, a filler, a dispersant, a thickener, etc., as a dissolver, Banbury mixer, planetary mixer, glen mill, open kneader. In addition, it can be produced by dispersing and mixing with a conventionally known mixing and dispersing machine such as a vacuum kneader.
[0051]
By blending the active ingredient in the base material as described above, the amount of dipole moment is dramatically increased, so that the pyroelectric material exhibits high pyroelectric performance. The amount of dipole moment in the pyroelectric material containing the components is expressed as a difference in dielectric constant (ε ′) between A and B shown in FIG. That is, the greater the difference in dielectric constant (ε ′) between A and B shown in FIG. 4, the greater the amount of dipole moment .
[0052]
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[0053]
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[0054]
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[0055]
【Example】
Example 1
DCHBSA is blended at a ratio of 100 parts by weight with respect to 100 parts by weight of polyvinyl chloride, and as shown in FIG. 5, it is formed into a plate shape having a thickness of 1 mm, a length of 150 mm and a width of 50 mm, and silver paste on both surfaces. An electrode (Asahi Chemical Laboratory, LS-506J, length 140 mm × width 40 mm) was formed as a sample.
[0056]
Example 2
A sample was prepared in the same manner as in Example 1, except that 2 HPMB was blended at a ratio of 100 parts by weight with respect to 100 parts by weight of polyvinyl chloride.
[0057]
Example 3
A sample was prepared in the same manner as in Example 1 except that 100 parts by weight of ECDPA was added to 100 parts by weight of polyvinyl chloride.
[0058]
Comparative Example 1
A sample was prepared in the same manner as in Example 1 using polyvinyl chloride alone.
[0059]
Comparative Example 2
A piezoelectric film made of polyvinylidene fluoride (PVDF) shown in FIG. 6 (KF piezo film, thickness 40 microns, length 100 mm × width 70 mm, manufactured by Kureha Chemical Co., Ltd.)
[0060]
First, the dielectric loss tangent (tan δ), dielectric loss factor (ε ″), and dielectric constant (ε ′) of each sample of Examples 1 to 3 and Comparative Example 1 were measured, and the results shown in Table 1 were obtained. The dielectric loss tangent (tan δ), dielectric loss factor (ε ″), and dielectric constant (ε ′) were measured at the glass transition point of each sample.
[0061]
[Table 1]

[0062]
Next, the pyroelectric performance of each of the samples of Examples 1 to 3 and Comparative Examples 1 and 2 was measured. As shown in FIG. 7, the front and back surfaces of the sample 11 and the voltmeter 12 are electrically connected to each other and placed on the base 10 made of a heat insulating material. A metal plate 14 heated to 100 ° C. was placed on 13, and the maximum voltage at that time was measured with a voltmeter 12, and the measured values are shown in Table 2.
[0063]
For comparison, the samples of Examples 1 to 3 and Comparative Examples 1 and 2 were subjected to a polling process (polarization process), and the pyroelectric performance was similarly measured for these samples. The polling process was performed by applying a 1 KV direct current for 1 hour in an oil bath at 100 ° C. for 1 hour, cooling to room temperature in that state, and removing the load.
[0064]
[Table 2]

[0065]
From Table 2, the value of Comparative Example 1 is 5 mV or 6 mV, which is a low value regardless of the presence or absence of polarization, whereas the non-polarized Examples 1 to 3 are about 1200 to 160 mV. The value was extremely high. In addition, the numerical values of Examples 1 to 3 when the polling process was performed also showed a high value of about 135 to 170 mV. In addition, the commercially available polarized comparative example 2 has a voltage of 119 mV, and even in comparison with this, it can be seen that the examples have superior pyroelectric performance. From these results, it was found that active components such as DCHBSA and 2HPMMB in the pyroelectric material greatly contributed to the improvement of pyroelectric performance.
[0066]
【The invention's effect】
The pyroelectric material of the present invention has an excellent pyroelectric performance that cannot be predicted from the pyroelectric performance of conventional pyroelectric materials, and does not require treatment such as stretching or polarization in its production. Very cheap.
[0067]
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[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a dipole in a pyroelectric material .
FIG. 2 is a schematic diagram showing a state of a dipole in a pyroelectric material when energy (heat) is transmitted.
FIG. 3 is a schematic diagram showing a dipole state in a pyroelectric material when an active ingredient is blended in the base material.
FIG. 4 is a graph showing the relationship between dielectric constant (ε ′) and dielectric loss factor (ε ″) in a pyroelectric material.
5 is a schematic view schematically showing films made of pyroelectric materials of Examples 1 to 3 and Comparative Example 1. FIG.
6 is a schematic view schematically showing a film made of a pyroelectric material of Comparative Example 2. FIG.
7 is a schematic view schematically showing an apparatus for measuring pyroelectric performance of films made of pyroelectric materials of Examples 1 to 3 and Comparative Examples 1 and 2. FIG.
[Explanation of symbols]
1 ... Pyroelectric material 2 ... Dipole

Claims (3)

Polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polymethyl methacrylate, polystyrene, styrene-butadiene-acrylonitrile copolymer, acrylic rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, butadiene rubber, natural rubber , isoprene rubber, a base material made of a polymer selected from chloroprene rubber, and chlorinated polyethylene,
As an active ingredient for increasing the amount of dipole moment in the base material, N, N-dicyclohexylbenzothiazyl-2-sulfenamide (DCHBSA), 2-mercaptobenzothiazole (MBT), dibenzothiazyl sulfide (MBTS), N-cyclohexylbenzothiazyl-2-sulfenamide (CBS), N- tert -butylbenzothiazyl-2-sulfenamide (BBS), N-oxydiethylenebenzothiazyl-2-sulfenamide (OBS) N, N-diisopropylbenzothiazyl-2sulfenamide (DPBS), 2- {2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 ″ tetrahydrophthalimidemethyl) -5 '-Methylphenyl} -benzotriazole (2HPMMB), 2- {2'-hydroxy-5'- Tylphenyl} -benzotriazole (2HMPB), 2- {2′-hydroxy-3′-t-butyl-5′-methylphenyl} -5-chlorobenzotriazole (2HBMPCB), 2- {2′-hydroxy-3 ′ , 5′-di-t-butylphenyl} -5-chlorobenzotriazole (2HDBPCB), ethyl-2-cyano-3,3-di-phenyl acrylate And
A pyroelectric material comprising an active ingredient in a proportion of 10 to 200 parts by weight with respect to 100 parts by weight of a base material. Base material, polyvinyl chloride, chlorinated polyethylene, acrylic rubber, acrylonitrile - butadiene rubbers, styrene - butadiene rubbers, and pyroelectric material according to claim 1, wherein a formed of polar polymer selected from chloroprene rubber. The base material has a glass transition point in the operating temperature range, from polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polymethyl methacrylate, polystyrene, and styrene-butadiene-acrylonitrile copolymer. A polymer selected by adding a plasticizer selected from di-2-ethylhexyl phthalate, dibutyl phthalate, diisononyl phthalate, or acrylic rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, butadiene rubber, natural rubber, isoprene rubber pyroelectric material according to claim 1, wherein the consisting of those consisting of a polymer selected from chloroprene rubber, and chlorinated polyethylene.

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