JPS62174187A - Multicolor thermal recording material - Google Patents

Abstract

PURPOSE:To enhance color separability and to prevent the generation of color mixture, in a multicolor thermal recording material containing a color eraser, by using a specific compound as the color eraser. CONSTITUTION:As the color eraser of a multicolor thermal recording material, a compound represented by general formula (1) (wherein R is an alkyl group, a cycloalkyl group, an aralkyl group or an aryl group and n is an integer of 2-20) is used. This compound is generally a white powder and hardly soluble in water and can be used as the color eraser but can be also used along with other common color eraser. The use amount thereof can be appropriately selected but 1.0-5.0g/m<2> is proper. The leuco dye used in this multicolor thermal recording material is sued alone or as a mixture of two or more kinds of one and, as this leuco dye, one adapted to this kind of a thermal recording material is arbitrarily adapted. As a coupler allowing the aforementioned leuco dye to form a color through reaction at the time of heating, various electron acceptive substances are adapted and a phenolic substance, an org. or inorg. acidic substance or a metal salt thereof, an aromatic amide compound and an aromatic urea compound etc. are designated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a multicolor heat-sensitive recording material, and more particularly to a multicolor heat-sensitive recording material formed by laminating a plurality of heat-sensitive coloring layers having different color tones.

[Prior art]

A thermosensitive recording material is a material in which a thermosensitive coloring layer capable of forming a colored image by heating is provided on a support such as paper, and a thermal printer equipped with a thermal head is widely used for heating.

These conventional heat-sensitive recording materials include a colorless or light-colored leuco dye (color-forming main agent) having a lactone ring, lactam ring, spiropyran ring, etc. in the heat-sensitive coloring layer, and a color developer that develops color by reacting with this leuco dye when heated. Agent (color development aid)
Those containing these are widely used because they have clear color tones and less fogging.

By the way, heat-sensitive recording materials can easily produce colored images just by heating them, so they are not only used for copying books, documents, etc., but are also used in various fields such as computer, facsimile, telex, and other fields for recording various types of information and measuring equipment. However, depending on the purpose of recording, in order to display particularly necessary data and numbers more clearly, the coloring of that part (
It goes without saying that it is desirable to be able to record with the display color (displayed color) different from the developed color of other parts.

Recently, attempts have been made to obtain multicolor recording by utilizing differences in heating temperature or thermal energy, and various multicolor thermosensitive recording papers have been proposed accordingly. Multi-color thermosensitive recording paper is generally formed by stacking two types of high-temperature and low-temperature coloring layers that develop different tones with different coloring heat energies on a support, and can be broadly classified into the following two types: Divided into types. One is to mix the color with the color tone of the low temperature coloring layer when coloring the high temperature coloring layer to obtain a color tone different from the coloring tone of the low temperature coloring layer, and the other is to color the high temperature coloring layer. In this case, by using a decoloring agent that decolorizes the low-temperature color-forming layer, only the color tone of the high-temperature color-forming layer is obtained without color mixture of the color tone of the low-temperature color-forming layer. As specific examples of these, the former is disclosed in Japanese Patent Publication No. 49-69, Japanese Patent Publication No. 4342-1972, Publication No. 27708-1977,
JP-A No. 48-86543, JP-A No. 49-6523
9, etc., and the latter was published in the Special Publication No. 1973.
-17865 Publication, Special Publication No. 50-17866,
Special Publication No. 51-29024, Special Publication No. 51-8754
Publication No. 2, JP-A-50-18048, JP-A-53
-47843, etc., respectively.

However, in the case of the former multicolor thermosensitive recording paper,
When coloring at a high temperature, the color tones that can be concretely achieved in order to mix the color with the color tone of the low temperature coloring layer are limited to black threads where the high temperature coloring tone is strong, such as red-black, blue-black, etc. There is. On the other hand, in the case of the latter multicolor thermosensitive recording paper, the combination of color tones can be freely selected, but when high temperature coloring occurs, it is necessary to provide a color erasing layer containing a color erasing agent to erase the color of the low temperature coloring layer. There is. It has been proposed to use aliphatic amines, aromatic amines, polyethers, etc. as such decolorizing agents. However, these decoloring agents have the disadvantage that they do not sufficiently decolor the coloring layer, resulting in mixed colors.

〔the purpose〕

An object of the present invention is to overcome the problems of the prior art described above, and to provide a multicolor thermosensitive recording material that has excellent color separation properties and does not cause color mixing.

〔composition〕

According to the present invention, in a multicolor thermosensitive recording material having a laminated structure of a plurality of heat-sensitive coloring layers that develop colors in different tones and containing a decoloring agent, the decoloring agent is represented by the following general formula (I).
A multicolor heat-sensitive recording material characterized by using a compound represented by:

(In the formula, R represents an alkyl group, a cycloalkyl group, an aralkyl group, or an aryl group, and n represents an integer of 2 to 20.) In the present invention, a plurality of heat-sensitive coloring layers that develop colors in different tones are formed on a support. In the multicolor heat-sensitive recording material, which has an interlayer between each heat-sensitive coloring layer and an intermediate layer for isolating a decoloring layer and an adjacent layer, if necessary, at least one of the layers has a compound represented by the general formula (I). Because it contains a compound that
It is possible to obtain a multicolor heat-sensitive recording material that has excellent color separation properties and does not cause color mixture.

The compound of general formula (1) used in the present invention is usually
It is a white powder that is easily soluble in water and can be used as a decolorizing agent, but it can also be used in combination with other commonly used decolorizing agents. In addition, the amount used can be selected as appropriate, but 1.0gI
r1-5. Og/rrF is suitable.

Specific examples of the compound of general formula (I) include the compounds shown below.

■, 3-bis(N-acetylpiperidyl)propane, 1
．． 4-bis(N-acetylpiperidyl)butane, 1.5
-bis(N-acetylpiperidyl)pentane, ■, 6-
Bis(N-acetylpiperidyl)hexane, 1.8-bis(N-acetylpiperidyl)octane, 1.3-bis(N-pivaloylpiperidyl)propane, 1.4-bis(N-pivaloylpiperidyl) Butane, ■, 5-bis(
N-pivaloylpiperidyl)pentane, 1,6-bis(
N-pivaloylpiperidyl)hexane, 1,8-bis(
N-pivaloylpiperidyl) octane, 1,3-bis(
N-octanoylpiperidyl)propane, 1,4-bis(N-octanoylpiperidyl)butane,
■, 5-bis(N-octanoylpiperidyl)pentane, 1,6-bis(N-octanoylpiperidyl)hexane, 1.8-bis(N-octanoylpiperidyl)octane, 1.3-bis(N- lauroylpiperidyl)prono(n,1,4-bis(N-lauroylpiperidyl)butane,
1.5-bis(N-lauroylpiperidyl)pentane,
1.6-bis(N-lauroylpiperidyl)hexane,
■, 8-bis(N-lauroylpiperidyl)octane,
1.3-bis(N-cyclohexylcarbonylpiperidyl)propane, 1.4-bis(N-cyclohexylcarbonylpiperidyl)butane, 5-bis(N-cyclohexylcarbonylpiperidyl)pentane, 1.6- Bis(N-cyclohexylcarbonylpiperidyl)hexane, 1.8-bis(N-cyclohexylcarbonylpiperidyl)octane, 1.3-bis(N-benzoylpiperidyl)propane,
1.4-bis(N-benzoylpiperidyl)butane, 1
．． 5-bis(N-benzoylpiperidyl)pentane, 1
．． 6-bis(N-benzoylpiperidyl)hexane, 1
．． 8-bis(N-benzoylpiperidyl)octane, 1
．． 3-bis(N-m-toluoylpiperidyl)propane, 1.4-bis(N-m-toluoylpiperidyl)butane, 1.5-bis(N-m-toluoylpiperidyl)pentane, 1.6- Bis(N-m-toluoylpiperidyl)hexane, 1.8-bis(N-m-toluoylpiperidyl)octane, 1.3-bis(N-p-toluoylpiperidyl)propane, 1.4-bis( N-p-toluoylpiperidyl)butane, 1,5-bis(N-p-toluoylpiperidyl)pentane.

1.6-bis(N-p-toluoylpiperidyl)hexane, 1.8-bis(N-p-toluoylpiperidyl)octane, 1.3-bis(N-phenylacetylpiperidyl)propane, 1.4- Bis(N-phenylacetylpiperidyl)butane, 1.5-bis(N-phenylacetylpiperidyl)pentane, 1.6-bis(N-phenylacetylpiperidyl)hexane, 1.8-bis(N-phenylacetylpiperidyl) Octane, 1.3-bis(N-p-anisoylpiperidyl)propane, 4-bis(N-p-anisoylpiperidyl)butane, 1.5-bis(N-p-anisoylpiperidyl)pen=
8-thane, 1,6-bis(N-p-anisoylpiperidyl)hexane, 1,8-bis(N-p-anisoylpiperidyl)octane, ■,3-bis(N-p-anisoylpiperidyl) Propane, 1,4-bis(N-p-anisylpiperidyl)butane,
1.5-bis(N-p-anisylpiperidyl)pentane, 1.6-bis(N-p-anisylpiperidyl)hexane, 1.8-bis(N-p-anisylpiperidyl)octane, 1. 3-bis(N-stearoylpiperidyl)propane, 1.4-bis(N-stearoylpiperidyl)butane,
■, 5-bis(N-stearoylpiperidyl)pentane, 1,6-bis(N-stearoylpiperidyl)hexane, 1,8-bis(N-stearoylpiperidyl)octane, The leuco dye used in the present invention may be used alone or in combination. These leuco dyes are applied by mixing more than one species.
Those applied to this type of heat-sensitive material can be arbitrarily applied. For example, leuco compounds of dyes such as triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, and indolinophthalide-based dyes are preferably used. .

Specific examples of such leuco dyes include those shown below.

3.3-bis(p-dimethylaminophenyl)-phthalide, 3.3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone), 3.3-bis(P- dimethylaminophenyl)-6-diethylaminophenyl, 3.3-bis(p-dimethylaminophenyl)-6-chlorophthalide, 3.3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlor Fluoran, 3-dimethylamino-5,7-dimethylfluoran, 3
-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-6
-Methyl-7-chlorofluorane, 3-(N-p-tolyl-N-ethylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2- (N-(3'-trifluoromethylphenyl)
amino)-6-ethylaminofluorane, 2-(3
, 6-bis(diethylamino)-9-(o-chloroanilino)xantylbenzoic acid lactam), 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran, 3-diethylamino-7-(O- chloroanilino)fluoran, 3-dibutylamino-7-(O-chloroanilino)fluoran.

3-N-methyl-N-amylamino-6-methyl-7-
Anilinofluorane.

3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-(N,N-diethylamino)-5- Methyl-7-(
N.

N-dibenzylamino)fluoran, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrillospirane, 6'-bromo-3'-methoxy-benzoindolino-pyrillospirane, 3-(2'- Hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-chlorophenyl)phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl) to 3-(2'-methoxy-5 '-nitrophenyl)phthalide, 3-(2'-hydroxy-4'-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl)phthalide, 3-(2'-methoxy-4'- dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-51
-methylphenyl)phthalide, 3-morpholino-7-(N-propyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7-( N-benzyl-trifluoromethylanilino)fluoran, 3-pyrrolidino-7-(di-p-chlorophenyl)methylaminofluoran, 3-diethylamino-5-chloro-7-(α-phenylethylamino)fluoran, 3-(N-ethyl-p-toluidino)-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-(o-methoxycarbonylphenylamino)fluoran, 3-diethylamino-5-methyl-7-( α-phenylethylamino)fluorane.

3-diethylamino-7-piperidinofluoranylethylamino)fluorane, 3-diethylamino-7-piperidinofluorane, 2-
Chloro-5-(N-methyltoluidino)-7-(p-n
-butylanilino)fluorane.

3-(N-benzyl-N-cyclohexylamino)-5
, 6-penzo 7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino 4
',5'-benzofluorane etc.

In the present invention, various electron-accepting substances are used as the color developer that reacts with the leuco dye when heated to develop color, including phenolic substances, organic or inorganic acidic substances, or their gold content. lt-, etc., and specific examples thereof are shown below.

Clay, activated clay, activated silica, boric acid, zinc oxide, zinc chloride, aluminum chloride, 4,4'-isopropylidene bisphenol, 4,4'-isopropylidene bis-(0-cresol), 4,4'-isopropylene Redenbis (o-t, crt, -butylphenol), 4
．． 4'-isopropylidene-bis(0-chlorophenol), 4,4'-cyclohexylidenebisphenol, 4,4'-bisphenolsulfone, 4-hydroxy-4'-chloro-diphenylsulfone, 4-hydroxy-4 '-isopropoxydiphenylsulfone, isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, p-chlorobenzyl p-hydroxybenzoate, salicylic acid anilide, salicylic acid (0-chloroanilide), salicylic acid (n-trifluoro) methylanilide), dimethyl 4-hydroxyphthalate, 2-hydroxy-3-naphthoic acid, benzyl 2-hydroxy-3-naphthoic acid, 2-hydroxy-3-naphthoic acid anilide,
2-hinylnitylamino)fluorane, 3-diethylamino-7-piperidinofluorane, 2-
Chloro-5-(N-methyltoluidino)-7-(p-n
-butylanilino)fluoran, 3-(N-benzyl-N-cyclohexylamino)-5
, 6-penzo 7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino 4
',5'-benzofluorane etc.

In the present invention, various electron-accepting substances are used as the color developer that reacts with the leuco dye to develop color when heated, such as phenolic substances, organic or inorganic acid substances, or metal salts thereof, aromatic amide compound,
Examples include aromatic urea compounds, and specific examples thereof are shown below.

Clay, activated clay, activated silica, boric acid, zinc oxide, zinc chloride, aluminum chloride, 4,4'-isopropylidene bisphenol, 4,4'-isopropylidene bis-(0-cresol), 4,4'-isopropylene Redenbis(o-ter-butylphenol 4,4'-
Isopropylidene-bis(O-chlorophenol), 4
, 4'-cyclohexylidene bisphenol, 4,4
'-Bisphenolsulfone, 4-hydroxy-4'-
Chloro-diphenylsulfone, 4-hydroxy-4'-
Isopropoxy diphenyl sulfone, isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, P-chlorobenzyl p-hydroxybenzoate, salicylic acid anilide, salicylic acid-(0-chloroanilide)
, salicylic acid-(n-trifluoromethylanilide), 4
-dimethyl hydroxyphthalate, 2-hydroxy-3-
Naphthoic acid, benzyl 2-hydroxy-3-naphthoate, zinc droxy-3-naphthoate, zinc chloride/antipyrine complex, methylenebis-(oxyethylenethio)diphenol, 4-hydroxyacetophenone, novolac type phenolic resin, novolac type phenyl Phenol resin, diphenylthiourea, di(m-chlorophenyl)thiourea, di(m-trifluoromethylphenyl)thiourea, etc.

In the present invention, in order to bind and support the leuco dye and color developer on the support, various commonly used binders can be used as appropriate, such as polyvinyl alcohol, starch and its derivatives, cellulose, hydroxyethylcellulose, carboxymethylcellulose,
Cellulose derivatives such as methylcellulose and ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone,
Acrylic amide/acrylic ester copolymer, acrylic amide/acrylic ester/methacrylic acid ternary copolymer, styrene/maleic anhydride copolymer alkali salt, isobutylene/maleic anhydride copolymer alkali salt, poly Acrylamide, sodium alginate, gelatin,
In addition to water-soluble polymers such as casein, polyvinyl acetate, polyurethane, styrene/butadiene copolymer, polyacrylic acid, polyacrylic acid ester, vinyl chloride/vinyl acetate copolymer, polybutyl methacrylate, ethylene/vinyl acetate copolymer, etc. Latexes such as polymers and styrene/butadiene/acrylic copolymers can be used.

In addition, in the present invention, in addition to the leuco dye and color developer, if necessary, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers, surfactants, thermofusible substances ( or lubricant), etc. can be used in combination. In this case, fillers include, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, and surface-treated inorganic fine powders such as calcium and silica. , urea-formalin resin, styrene/methacrylic acid copolymer, polystyrene resin, and other organic fine powders. Examples of thermofusible substances include higher fatty acids or their esters, amides, or metal salts. In addition, various waxes, condensates of aromatic carboxylic acids and amines, benzoic acid phenyl esters, higher linear glycols, dialkyl 3,4-epoxy-hexahydrophthalates, higher ketones, and other thermofusible organics. Examples include compounds having a melting point of about 50 to 200°C.

For example, in order to obtain a two-color heat-sensitive recording material according to the present invention, a liquid in which a color-developing dye, a color developer, a decolorizing agent, a binder, etc. are dispersed or dissolved on a support such as paper, synthetic paper, or plastic film is used. It can be obtained by applying it, drying it, and repeating it. When further laminating on top of the coated layer, it is necessary to pay close attention to the solubility and releasability of the layer so that the lower layer does not mix with the upper layer. Further, after coating and drying, the upper layer may be applied after calendering. The amount of dye attached to the high-temperature coloring layer is 0.3 g/nf to 1.0 g/nf. Og/d, the amount of decolorizing agent attached to the decolorizing agent layer is 1.0 g/rrr to 10 g/
rri', and the amount of the low-temperature coloring layer deposited is 0.2 g/deposit of the leuco dye as a dry product, as described above.
J~0.5g/rrf. When a protective layer is provided, the amount of adhesion is preferably 0.5 g/rr1' to 5.0 g/rrF. When providing an intermediate layer between the decoloring agent layer and the low-temperature coloring layer or between the decoloring agent layer and the high-temperature coloring layer, the former is 0.5 g/r.
d~5. Og/ryf is preferred, the latter being Ig/i~1
0 g/n (preferably.

Furthermore, by further increasing the number of thermosensitive coloring layers in the same manner as described above, it is also possible to obtain a multicolor thermosensitive recording material having three or more colors.

=20- [Effect] The multicolor heat-sensitive recording material of the present invention has the above-mentioned structure, and by using the compound of the general formula (1) as a decolorizing agent, it is possible to clearly produce a plurality of tones without mixing colors. It provides multicolor images with excellent brown color separation.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples. Note that all parts and percentages shown below are based on weight.

Examples 1 to 5 Each of the following ingredients was heated using a ball mill for 24 hours.
1 was pulverized and dispersed to prepare dispersions A-D.

[Dispersion liquid-A]

10% hydroxyethylcellulose aqueous solution 2o water
6
0//[Dispersion-B] 3.3'-dichlorophenylthiourea io part N-stearylbenzamide 1o Calcium carbonate 15 parts Polyvinyl alcohol (10% aqueous solution) 3Qn water
40 [Dispersion liquid-
C] 3-diethylamino-7-chlorofur 20 parts orane (red) 10% hydroxyethylcellulose aqueous solution 20II water
60//[Dispersion-D] 3.3-Dichlorophenylthiourea 10 parts Calcium carbonate 10II 10% aqueous solution of polyvinyl alcohol 201I Water
60! !
[Dispersion-F] Crystal violet lactone (blue) 20 parts 10%
Hydroxyethyl cellulose aqueous solution 2011 water
601
! [Dispersion-F] Bisphenol A 10 parts Calcium carbonate 10H2O% hydroxyethylcellulose aqueous solution 15II water
65 parts or more of dispersion A prepared as above, 10 parts, 860 parts of dispersion,
30 parts of water were each taken and mixed and stirred to obtain a thermosensitive color forming liquid for low temperature use. On the other hand, 010 parts of dispersion liquid, 70 parts of dispersion liquid D, and 20 parts of water were each taken and mixed and stirred to obtain a thermosensitive coloring layer forming liquid for medium temperature coloring.

Further, 70 parts of dispersion EIO part 1 dispersion F and 20 parts of water were each taken and mixed and stirred to obtain a thermosensitive coloring layer forming liquid for high temperature coloring. Further, a decolorizing agent layer forming liquid for forming a decolorizing agent layer was prepared at the following ratio.

[Decolorizer layer forming liquid]

Decoloring agent in Table-1 20 parts lO%
Polyvinyl alcohol aqueous solution 20! l water
60
! ! Next, on commercially available high-quality paper with a basis weight of about 52 g/rrf,
The above-mentioned high temperature thermosensitive coloring layer forming liquid (dry coating amount: 5 g/
rrr ), erasing agent layer forming liquid (dry coating amount 3 g/d)
, terpene resin latex (solid content 40%) as intermediate layer forming liquid (dry coating amount 3 g/m2), medium temperature thermosensitive coloring layer forming liquid (dry coating amount 4.5 g/rrf), decolorizing agent layer forming liquid (drying 23 temporary coating amount 3g/i), terpene resin latex (solid content 4%) as intermediate layer forming liquid (drying coating amount 3g/rrF
), low-temperature thermosensitive color forming layer forming liquid (dry coating amount: 4 g/♂) was applied and dried in sequence, and then the smoothness was 500 to 1000 seconds.
Examples 1 to 1 of the present invention were calendered so that
Ten multicolor thermosensitive recording materials were prepared.

Comparative Example 1 In Example 1, 1,3-bis(N
-benzoylpiperidyl) N, N' instead of propane
, Example 1 except that N"-triphenylguanidine was used.
A heat-sensitive recording material for comparison was prepared in the same manner as described above.

Comparative Example 2 In Example 1, 1,3-bis(N
-benzoylpiperidyl) N, N'- instead of propane
A comparative heat-sensitive recording material was prepared in the same manner as in Example 1, except that diphenyl-N'-cyclohexylguanidine was used.

Table 1 The multicolor thermosensitive recording materials of Examples and Comparative Examples obtained as described above were tested for dynamic coloring characteristics using a G-II facsimile test machine.

The test machine was an 8 dot/m manufactured by Matsushita Electronic Components Co., Ltd.
It has a full head, the heating element resistance is approximately 400Ω/dot, and the color development test was performed at a main scanning recording speed of 20m5.
ec/1ine, sub-scanning 3.85 fl/m
m, platen suppression 3.0kg/cJ, head input 0.6
The test was conducted under the following conditions: The coloring energy was 1.0 mJ for the low temperature coloring layer, 2.0mJ for the medium temperature coloring layer, and 3.3mJ for the high temperature coloring layer.

In addition, a Macbeth densitometer was used to measure the concentration.

As a result of the test, in Examples 1 to 5, the three constituent colors were clearly separated and developed, whereas in Comparative Example 1.2, the three constituent colors exhibited mixed color.

Claims (1)

[Claims] (1) A multicolor thermosensitive recording material having a structure in which a plurality of heat-sensitive coloring layers that develop colors in different tones are laminated and containing a decoloring agent, characterized in that a compound represented by the following general formula is used as the decolorizing agent. A multicolor heat-sensitive recording material. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R represents an alkyl group, cycloalkyl group, aralkyl group, or aryl group, and n represents an integer from 2 to 20.)