JPS6243643A - Color photographic sensitive material giving image with improved shelf stability - Google Patents

Abstract

PURPOSE:To improve the shelf stability of an image by forming a back layer of a specified copolymer on the rear side of a transparent support having a color image forming layer on the front side so as to absorb ultraviolet rays as well as to isolate oxygen. CONSTITUTION:An image forming layer is formed on one side of a transparent support, a back layer of a copolymer having units represented by formulae I, II is formed on the other side, and an ultraviolet absorber represented by formula III [where X is H, halogen, alkyl, alkoxy, phenyl, -OR1 or the like; each of Y and Z is H, halogen, alkyl, -OR2 or the like; each of R1 and R2 is H, alkyl, alkenyl, cycloalkyl, phenyl, -CO(NH)n-D or the like; n=1 or 2; D is H, alkyl, phenyl or the like; and the total of the pi values of X, Y and Z satisfy formula IV] is incorporated into the back layer. The ultraviolet absorber has a great affinity for the copolymer in the back layer, so when the resulting film is dried, trouble such as the staining of the inside of a drier or the surface of the film can be prevented. The shelf stability of a color image is improved and the increase of a yellow stain can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a photographic light-sensitive material, and particularly to a color photographic light-sensitive material with improved image storage stability.

(Prior Art) A color photographic light-sensitive material is provided with a color image forming layer on one side of a transparent support and a back layer formed of a copolymer containing at least +CH2-CH2→ on the other side. Known by Tokuko Sho Yota U//73. Conventionally, various plastic films such as cellulose acetate film and polyethylene terephthalate film, which have been used as photographic supports, are permeable to oxygen, so the storage stability of photographic images is affected by the oxygen, especially when exposed to light for long periods of time. Discoloration and fading when photographic film is used, as well as fluctuations in quality between the time it is manufactured and the time it is used by the user, were serious problems.
7! Since the back layer according to the invention of No. 1 has superior oxygen blocking ability, this problem could be solved extremely effectively.

(Problem to be Solved by the Invention) In order to more effectively prevent discoloration and fading of color images, it is sufficient to block ultraviolet rays, and for this reason, the use of an ultraviolet absorber is taught in the above-mentioned published specification. There is.

The greater the ultraviolet absorbing ability of the back layer, the better the light storage stability of color images will be. However, there are no conventional ultraviolet absorbers that can be added to the back layer in large quantities, so it is necessary to increase the film thickness. An attempt was made to increase the ultraviolet absorption ability.

However, when the film thickness was increased, curling increased and the flatness of the photographic film deteriorated.

Additionally, if a back layer containing an ultraviolet absorber is stored in wet conditions after film formation, the ultraviolet absorber will seep out onto the film surface (bleed) and precipitate on the surface, significantly reducing the transparency of the film. However, there was a problem in that the image density when viewed from the back side was extremely low.

In addition, when the coating temperature was raised to prevent the permeability of the coating, another problem arose in that the ultraviolet absorber was dispersed into the drying air and contaminated the coating machine due to precipitation in the cooling zone.

Furthermore, if such scattering of the ultraviolet absorber occurs during coating and drying, not only will the ultraviolet absorbing ability of the backing layer decrease,
If the drying air cools down even a little, precipitation will occur in various places in the drying zone, and when another coated film passes through the drying zone, the deposits will adhere and cause problems such as "repelling", "bumps", and "streaks". There was also the problem of causing

Accordingly, an object of the present invention is to provide a color photographic material which effectively blocks oxygen and absorbs ultraviolet rays, thereby improving image storage stability without causing the various problems mentioned above.

(Means for Solving the Problems) The above object is to provide a color photograph having a color image forming field on one side of a transparent support and a back layer formed by a copolymer containing at least ÷CHz-CH2→ on the other side. This has been effectively achieved using a color photographic material characterized in that the back layer contains a compound represented by the following general formula.

General Formula (1) In the formula, X represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a phenyl group, a substituted phenyl group, an alkylcarbonyl group, an alkylcarbonyl group, or -0Rt.

Y and 2 each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxycarbonyl group, or -0R2.

R1 and R2 are a hydrogen atom and an alkyl group, respectively.

Alkenyl group, cycloalkyl group, aralkyl group, phenyl group, substituted phenyl group, acyl group or -Co(NH)
Represents n-D.

n is/or λ, and D represents a hydrogen atom, an alkyl group, an alkenyl group, a phenyl group or a substituted phenyl group. However, it is assumed that the sum of the π values of X%Y and Z satisfies the following conditions.

-1,3; 0≦8 redundancy≦-0.70 (i-X, Y, Z) The present invention will be explained in detail below.

In general formula (1), the alkyl group, alkoxy group, alkylcarbonyl group, alkylcarbonyl group, alkoxycarbonyl group, cycloalkyl group, alkenyl group, and aralkyl group in X, Y, Z, R, and R2 are substituted Hydrophilic groups are preferred as the substituents and the substituents of the substituted phenyl group, and specific examples include hydroxyl group, carboxyl group, nurpho group, and acyl group.

Specific examples of the ultraviolet absorber represented by the general formula (1) and the Σπ values of the substituents X, Y, and Z are shown in Table 1 below.

Table 1/2-OHμmOH-OH-2,0/ 3 l ≠-0CH3-Co2Q(3-0,7
/Hiro N μmOHrt −
/, 3jr tt tLL-0CH3-OC
H2COOH-/ , j7 Otsu #u-OH#
-λ, 2/7 x u OC
H30COI'J) 12 0. r! ; f t
t μmOH// -Ha≠Tata
〃μmOCH3-CH2COCH3-
/, 3ri10 1 μmOH〃
-ko, 03/ / # 4' 0CH3-OC
OC') (3/ -34'/2 1
tI-OH# - Grouper! The ultraviolet absorber has the structure of the general formula (1) above, and substituents x, y, z
When the Σπ value of is in the range of -3,30 to -0,70, the affinity with the copolymer used in the back layer of the present invention is specifically improved, and the object of the present invention is effectively achieved. I found out what I can do. Such findings were unexpected and surprising based on conventional techniques.

In addition, the π value of a substituent is defined in "Journal of the American Chemical Society" (J, Ame
r, Chem, Soc) r Volume 6 j/lt page (/9
This is the value defined by the following formula (11), which was reported in 2006.

π-1OgPx-1OgPH (1) Px is the distribution coefficient of the molecule derived from the parent molecule, and PH is the distribution coefficient of the parent molecule.

For example, the 7cα value of a chlorine group is determined by the following formula.

7CC,! -1ogPchlorobenzene-1ogpbenzone Partition coefficient P refers to the ratio of the concentration of a compound distributed between water and octanol measured using a spectrophotometer. The experimental conditions were: Octatool saturated with distilled water and distilled water saturated with Octatool;
Mix Oml of octatool and j0~μ00d of distilled water, change the concentration of the compound to be measured at the ≠ point, and after mixing, let it stand at 2j0C and find the concentration by measuring the spectral absorption of the aqueous phase. . The concentration of the octatool phase is determined by subtracting the concentration of the aqueous phase from the original addition concentration, and the average of each μ point is taken.

C octatool: Concentration of octatool phase C water:
Concentration α of aqueous phase: degree of dissociation Calculate the partition coefficient P using equation (2). However, α is O
Make the liquid acidic so that

The π value used in the present invention is determined by "Pharmaceutical Chemistry Magazine" (J.

of Medicinal Chemistry)/
The values reported in Table 7 of Volume 6, Issue 11, Page 7207 (1973) are used. Note that the numerical values in this report were calculated as substituents to aromatic groups.

For substituents not reported in Table 1 above, use the partition coefficient reported in "Chemical Reviews, Vol. 7, No. 6, p. 2j (1/7/year)." The distribution coefficients of substituents, which have not been reported in the "Chemical Cycle", can be determined using the experimental method described earlier and (2).
The distribution coefficient is determined using the formula, and the χ value is calculated based on the formula (1).

+cH2-C of the copolymer used in the back layer of the present invention
The ratio of H→copolymer component is preferably 30 moles H or more, more preferably tio moles or more.

The copolymer component of this copolymer may include a component derived from a lenically unsaturated monomer. Examples of ethylenically unsaturated heptamers include acrylic esters (such as methyl acrylate and n-butyl acrylate), methacrylic esters (such as methyl methacrylate and n-butyl methacrylate), and vinyl esters (such as methyl methacrylate and n-butyl methacrylate).
For example, vinyl acetate).

It is preferable that the ethylenically unsaturated septamer not be crosslinkable.

The back layer of the present invention may contain hydrophilic colloids such as gelatin in addition to the above-mentioned copolymers as long as the effects of the present invention are not impaired.

The ultraviolet absorber represented by general formula (1) is preferably 0
6 can be added in an amount that provides an absorbance of at least 2.0, more preferably at least 2.0. The upper limit of the amount added is not particularly important; it can be added up to a degree that does not cloud the back layer film. The concentration of the ultraviolet absorber is preferably 2 to 10% by weight of the polymer in the back layer.

The coating amount of the above-mentioned copolymer constituting the back layer is ~/I
f/m" is preferred.

Among the compounds represented by the general formula CI) used in the present invention, λs2'aupμ'-tetrahydroxyhensiphenone is commercially available as tJVINUL D-30 (manufactured by BASF).

Other compounds are also known from Japanese Patent Publication No. 36-126g6.

As long as the effects of the present invention are not impaired, the ultraviolet absorber represented by general formula CI) may be used in combination with other ultraviolet absorbers (for example, 2.<z-hydroxybenzophenone, etc.).

The transparent support used in the present invention is preferably one that does not undergo significant dimensional changes during processing. Examples of such supports include cellulose acetate films, polynutylene films, polyethylene terephthalate films, polycarbonate films, etc. which are used in common photographic materials.

The color image forming layer coated on the transparent support may be a mordant layer (object layer) that mordants the dye that is formed or released and diffused into an image as a result of exposure and development, or may be a mordant layer that mordants the dye that is released and diffused It may also be a layer containing an image-providing substance.

A color image is formed as a result of exposure and development of silver halide and the dye image-providing substance, directly or indirectly by a redox reaction, or by an oxidative coupling reaction. The silver halide and the dye image-providing material may be in the same layer or in layers adjacent to each other.

The dye image-providing materials used in the present invention are negative-working or positive-working, as known to those skilled in the art, and are mobile or immobile in alkaline solutions.

The most typical dye image-providing substances are color couplers used in 1" conventional color sensitive materials.

Negative-working dye image-providing materials useful for color diffusion transfer methods and photothermographic materials include couplers that react with oxidized color developers to form or release dyes, specific examples of which are described in U.S. Pat. λ,! No. 7.360 and Canadian patent toi, t.

7, etc. A particularly preferred negative dye image-providing substance is a dye-releasing redox compound (DRR compound) that releases a dye by reacting with a developing agent or an electron transfer agent in an oxidized state. Showa Kg-33121, issue, same! It is described in μm54tol1, μm5i-ii362tA, and μmjls-71072.

Immobile positive-working dye image-providing materials that may be used in the present invention include those that do not accept any electrons (i.e., are not reduced) or that accept at least 7 electrons during photographic processing. There are compounds that release a diffusible dye after being reduced (ie, reduced).

Further, as a positive-type dye image-providing substance that is mobile in an alkaline solution and is effective in the present invention, there are dye developers,
Typical specific examples thereof are described in Japanese Patent Publication No. Sho μg-32/30 and JJ-227 Za0.

The dyes formed from the dye image-providing materials used in this invention may be ready-made dyes or alternatively dye precursors that can be converted into dyes in photographic processing steps or additional processing steps to achieve the final image quality. The dye may or may not be metallized. Typical dye structures useful for color diffusion transfer methods and heat-developable light-sensitive materials include metalized or non-metalized dyes such as azo dyes, azomethine dyes, anthraquinone dyes, and phthalocyanine dyes. Among these, azo-based cyan, magenta and yellow dyes are particularly important.

Specific examples of yellow dye image-providing substances that can be used in the present invention include Japanese Patent Publication No. 261g, U.S. Pat.
．． No. 197, Tokuko Akira! ;7-/2/≠0 issue, Tokukai Sho! /
-//No. 4173o, same! It-///314&, rl,-/l, 730, 5J6-7107; JP-A-Shoj μm 7903/; JP-A-Sho-J3-641031.
No. 5p-23s27; U.S. patent tll daza;
6q/ and same 4<, /iJ! , Otsuq3; "Research Dinuklosure" (Research ])isclo
sure) / 7A30 (777g), same 76 7j
(/ri77).

Similarly, specific examples of magenta dye image-providing substances are described in US Patent No. 3. μ33,107, Japanese Patent Publication Sho≠6-≠39yo0 and Japanese Patent Application Publication No. Sho32-106727, U.S. Patent No. 3.9'3
2.3♂No. 0, 3,93/.

/4? No. U, No. 3.932.301, JP-A Shoj.

-//3;! ;2g issue, same! 1.2-101.727, same! 3-,! 31. λg issue, same Ta≠-Otsu 6031 issue, same 3rd issue, 136g0q issue, same 34t-/l, /332 issue, same J! -40,2g issue, same K1. -730! ; No. 7,
same! flr-71060, 55-/3μ, jJ-
36! No. 33, U.S. Patent No. 207,10≠, [U.S.

Furthermore, the same (specific examples of cyan dye ion donor substances are given in Japanese Patent Publication No. 32/30, Japanese Patent Application Laid-open No. 32-Gza 27,
Same≠tar/2633/issue, 43/-10ri? ,! No. g,
Same j4L-Tata≠3] issue, same j3-7≠932za issue, same octopus-1g27 issue, same! 3-μ7g No. 23, same j3-/
Da 3323, Sμm Tata 143/ and jls
-7101, No. 7, same j3-Otsuμ03! Same as jμ−/2
/ /, 2j; U.S. Patent Ko, /4Z, 2. Go No. 27,
Same≠, llij, No. 274, Dohiro, /≠7. No. 1, same t
T, 1iar, Otori No. 2, European patent! 3,037
Same issue! 3,04lQ issue: “Research Disclosure”/
7.630 (/ri7f) and the same/Otsu, ≠7 (/ri7
7).

Further, as a dye precursor, a dye-releasing redocnu compound having a dye moiety that temporarily shifts light absorption in a photosensitive element can also be used in the present invention. ;-63330, same 3! -3332
No. 9, U.S. Pat. No. 3,331, . 2g7 issue, same 3, j7
9.33≠, 3゜2♂-2746, British patent/
, '1ly7, No. 3/7.

The color photographic material of the present invention can be developed with either a black and white developer or a color developer, and can also be developed by heating.

Image-receiving layers used for color diffusion transfer and thermal development preferably contain a polymer mordant. As the polymer mordant, polymers containing secondary and tertiary amine groups, polymers having nitrogen-containing heterocyclic moieties, polymers containing these high-class cation groups, etc., with a molecular weight of s, ooo or more are preferable, and particularly preferably. io, ooθ or more.

For example, US patents, 2. j4J', j & μ, same 2゜μg
μ, No. 4130, 3. / Hiroz, oti issue, same j, 7
j4, vinylpyridine polymers disclosed in U.S. Pat. 62j, Ari μ issue, same 3. Zajri, No. 096, Dohiro, /2g.

, tJg, British Patent/, 277, μ53, etc.; polymer mordants crosslinkable with gelatin, etc.; US Pat. Rijza, No. 275, same, 721.13
No. 2, No. 2, 7 Riza, No. 063, Tokukai Shojμm//! ,
2.2g issue, same j4t-/'43°32? No., same, 5u
-/26,027 issue, same j hiro-1ss, r3r issue, same!
Aqueous sol type mordant disclosed in ip-/7,362, etc.; US Pat. No. 3. Water-insoluble mordant disclosed in ♂rig, 0g1 specification, etc.; US Patent≠, 76g,
No. 276, IA, 20/, IμO, etc., reactive mordants capable of covalently bonding with dyes; and US Pat. No. 3.70? , 6ri 0, 3,7gg, za53
No. 3.6μ2. Hirot No. 2, No. 3.4! Iza, 7
No. 06, No. 3, 337, 0lsl.

No. 3, 27/, 7μ7, No. 3, 27/.

No. 141, % Kaisho 33-3032g issue, J2-/36
62g issue, 33-/2j issue, same! No. 3-1021A,
63-107. Za3μ, British patent 2.06μ, Za0
Examples include the pollutants disclosed in Specification No. 2 and the like.

Other U.S. patents λ, A'7j, j/A, 2゜zaza 2
, No. 114 can also be mentioned.

For details on other materials and layer structures used in photosensitive materials for heat development and photosensitive materials, see, for example, European Patent EP7A4.
! It is described in λA2.

Example/ A copolymer of vinyl acetate and ethylene was saponified to produce a copolymer component of vinyl alcohol and ethylene of 70 molt and 3
Copolymer containing 0 mol (trade name: Kuraray Eval EP)
103) / 2 no n-proper tool 1,269 and water 33
Put it in the mixed solvent of Hiro 1 and add it to the following 2nd! ! ! A coating solution was prepared by adding the compounds listed in Table 1 in the amounts listed in the table and stirring at 700C for 2 hours. This coating solution was coated on a polyethylene terephthalate film with a dry film thickness of 6 μm (dry film thickness) to prepare samples of the present invention and comparative wavelength.

/2.2'-hydroxy-μ-,2y-i,r7
Methoxy≠′-carboxymethoxybenzophenone-2-i! , -2' t 4'jμ'-tetra
1. Hirota -λ, 0/Hydroxybenzophenone comparison user 2-Hydroxy-Hiro-Methoki 0.79 -
0.02 dibenzophenone samples 1 and 2 and comparative sample 1 were measured using a high-resolution UV2AO spectrophotometer to determine the maximum absorbance in the ultraviolet region excluding the absorption of the polyethylene terephthalate film. In addition, after these samples were left in an atmosphere with 100% relative humidity for 2 days with booc, j cwh ×! I punched it out to a fake size. This surface was washed with about 1/jcc of n-propyl alcohol, the washing liquid was transferred to a 20cc menu flask, and the pressure was adjusted to 20cc with n-propyl alcohol.
The absorbance of the precipitated compounds shown in Table 2 was measured at the wavelength showing the maximum absorbance at each temperature using a V-colo type 0 spectrophotometer. The results are shown in Table 3.

Table 3 Sample / 2 Comparison wavelength (nm)
3170 330 31AO absorbance -,3,! To 2. ．． 20/, 1,060
°C, 100% R,H.

Precipitation after 2 days t O, 020, 0μ 0.23
From these results, Comparative A has an absorbance value of 7.60 at 3110 nm VC, which is clearly lower than the absorbance of the present invention. This is because the amount that can be added is limited, and if more than the second table amount is added, clouding will occur due to precipitation in the film. All samples of the present invention are 3pQn
It is possible to obtain an absorbance of 2.20 or more at m and also form a transparent film. Furthermore, in all of the samples of the present invention, bleeding of the ultraviolet absorber did not occur even in a humid heat atmosphere of 6000% R, H for 2 days, and the results in Table 3 also show low values. On the other hand, in the comparison case, bleeding occurred on the surface and precipitation occurred.

Photosensitive Sheet Po11 Ethylene terephthalate A back layer was provided by coating the coating solution described in Example 1 on a transparent support, and each layer was further coated on the other surface of the support as follows to prepare a photosensitive sheet. .

(1) The following polymer a:b:c:d-! :4t7. ! :j, j:image-receiving layer containing u2 at 3y/m'', gelatin at 3j'/m'' and n-about 30 as coating aid.

(2) Titanium oxide, 209/m! and gelatin 2
, 0917m2.

(3) Carbon black as solid content/, sp/
m2 and gelatin at 0.7jy/m'.

(4) The following cyan dye-releasing redocnu compound 0゜≠Q
p/m", tricyclohexyl phosphate) 0.0ri1
7m5.2.3-Gt-79decylhydroquinone 0.001p/m" and gelatin O0za9/m
A layer containing ``.

CH3 (CH (5) red-sensitive internal latent type direct positive bromide bale emulsion (with the amount of silver /
, q3y/m"), gelatin/, 2p/m", the following nucleating agent 0,04tq/m"
n-A antadecylhydroquinone sodium salt 007
3. Red-sensitive emulsion layer containing 7m''.

■Green-sensitive emulsion layer.

+91 Same layer as +61.

α＠ Yellow dye-releasing dotsukunu compound with the following structure (
0,! ;39/m"), tricyclohexylphonufate (0,1317m"), λ, 3-di-t
a layer containing antadecylhydroquinone<0.0/up/m") and gelatin 7C0,7P/m2).

aυ Blue-sensitive blue-sensitive inscribed positive silver bromide emulsion (in terms of silver amount /,
07ri7m2), gelatin (/, /17m”)
, same nucleating agent as layer (5) (0.041g97m”)
and a blue-sensitive emulsion layer containing 2-nurho-3-n-ntadecylhydroquinone sodium salt (o, o7y/m2).

A layer containing α-gelatin/, Op/m”.

The sensitive material sheets using the back layer of the present invention are respectively referred to as "Sensitive material of the present invention/Toco", and the sensitive material sheet using the comparative back layer is referred to as "Comparative sensitive material A".

A cover sheet was prepared by coating on a polyethylene terephthalate support in the following order.

fl) Acrylic acid-butyl acrylate (molar ratio g: 2) copolymer with an average molecular weight to, ooo was mixed with 2.2P/
m! Contains a neutralizing layer.

(2) Cellulose acetate with an acetylation degree of 3/3% (the weight of acetic acid released by hydrolysis is 0.3/3F per sample IP) and an average molecular weight of about 10. θOO
Nutylene-maleic anhydride (molar ratio /:/) copolymer with a weight ratio of 7! μ at a ratio of 30 to j 77m” J-
(β-Cyanethylthio)/-phenyl-tetrazole 0.37 oy/m'' neutralizing timing layer.

(3) Nutylene-bnalacrylate acrylic acid-N-methylolacrylamide weight ratio≠7゜7/μ2
．． Polymer latex was emulsion-polymerized with a ratio of 3/μ/Hiroshi and polymer latex was emulsion-polymerized with methyl methacrylate/acrylic acid/N-methylol acrylamide at a weight ratio of 73:3:≠. A layer containing A17m'' blended with a ratio of q to q.

After the photosensitive sheet was exposed through a symmetrical wedge, the cover sheet was placed on top of the other, and the following processing solution was spread between the two sheets to a thickness of 3 μm (spreading was done with the help of a pressure roller). ).

FPfL Processing was performed at yt'c.

Sensitive material of the present invention/and! After exposing the developed sample to a comparative sensitive material for 2 days in a xenon arc lamp photobleaching tester with one side of the symmetrical wedge side image shielded from light, the maximum red reflection a
The optical density (Dmax) and the blue minimum reflection density (Dmin) were measured in the light-shielding part and the light-exposed part, respectively, and the difference (ΔD) between the two was determined.

In the same way, one side was shielded from light and placed on a south-facing window glass exposed to sunlight and exposed to light for μ weeks, and similarly I) max and Dmi
The density difference between the light-shielded area and the light-exposed area was determined for n. The results are shown in Table 4.

4th surface material / 2 Comparison A xenon arc lamp 2 days ΔDmax -0,AO-0,3;! ;-/
, 00ΔDmi+1 +0. Og +0.
03 +0.30 sunlight q week ΔDmax -0, ,26-0,2≠-〇,J
OΔDmin ”0.0/ +0.0/
+0.10 From these results, the photosensitive materials of the present invention / and 2 are as follows:
Preservability (ΔI) ma of cyan color image was better than Comparative photosensitive material A in both xenon arc lamp test and Tai1i light exposure test.
x decreases (smaller) and yellow nutein increases (Δ
D? ! It can be seen that there is a significant improvement in both cases (with a small increase in 11in).

Claims (1)

[Claims] One side of the transparent support has a color image forming layer, and the other side contains at least a unit represented by -(CH_2-CH_2)- and a unit represented by ▲A mathematical formula, a chemical formula, a table, etc. A color photographic light-sensitive material having a back layer formed of a copolymer, characterized in that the back layer contains a compound represented by the following general formula [I]. General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ In the formula, X represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a phenyl group, a substituted phenyl group, an alkylcarbonyl group, an alkylsulfonyl group, or -OR_1 . Y and Z each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxycarbonyl group, or -OR_2. R_1 and R_2 are each a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aralkyl group, a phenyl group, a substituted phenyl group, an acyl group, or -CO(NH)_n
- represents D. n is 1 or 2, and D represents a hydrogen atom, an alkyl group, an alkenyl group, a phenyl group or a substituted phenyl group. However, it is assumed that the sum of the π values of X, Y, and Z satisfies the following conditions. -3.50≦Σπi≦-0.70 (i=X, Y, Z)