JPS61195891A - Composition for heat developing printing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to thermally developable printing inks that serve as protective films for recording papers and novels, particularly for food products in supermarkets, meatpacking plants, or similar environments. Concerning printing ink for labels used in packaging.

BACKGROUND OF THE INVENTION Heat-developable printing and coating compositions are known to be resistant to premature color development, especially when paper or film coated with the composition is exposed to high humidity. . Such compositions are disclosed in U.S. Pat. No. 4,500,354 and have a remarkable ability to form superior contrast indicia with a high degree of clarity and permanence, while also removes or minimizes printhead residue and wear after continuous printing. The printing and coating compositions described in this invention have a water stability (
Water-stab 1 e) phenol-amine complexes.

In addition to the aforementioned stability properties, controlled color development, and reduced printhead wear and contamination, heat-developable printing papers (stocks) are ideal for use in retail operations such as supermarkets, food distribution centers, or meatpacking. It should be resistant to conditions commonly encountered in packaging plants. For example, thermal labels with heat-developed trace marks when applied to plastic film packaging for food products may contain fat, vinegar, or alcohol compounds from the food itself or adjacent packaged products or the environment in which it was stored. Must be resistant to substances and water. A small amount of resistance can obscure the label indicia, reduce the contrast between the label substrate and the thermal image, and further reduce laser manipulation of the barcode printed on the label.

There is a risk that production will be disrupted. A similar result is
Migration of plasticizers from plastic packaging, pressure-sensitive adhesives commonly used in labels, and migration of acidic substances to paper continue to occur. . Such movement is often facilitated by stacking food products and can obscure trace indicia on the label and impede its visual or electronic reading.

Complex systems have been devised to protect thermal labels against the aforementioned deleterious effects. In one such system, the atoms of the label are attached to the front surface of the base paper (
The protective layer has a heat-developable coating and a transparent upper layer on the protective layer. Further, on the back side (lower surface) of the paper, there is provided a protective layer in contact with the paper, a pressure-sensitive adhesive on the protective layer, and a release backing paper in contact with the pressure-sensitive adhesive.

The protective layer provided on the back side acts as an impediment to the movement of the adhesive on the paper. The protective layer not only prevents substances on or in the label from migrating into the synthetic label, but also prevents active substances such as water, alcohol, vinegar, and fats from coming into contact with the label before or after development. to keep the thermal coating from deforming. Multilayer systems of the type described above are described in U.S. Pat. No. 4,388,362;
No. 401.721 and No. 4,444,819.

It is clear that the manufacture of such labels requires multi-coating processes and equipment. Furthermore, each layer or coating must be dried before another coating is applied. These requirements make it difficult to produce high quality labels at an affordable cost.

(Summary of the invention) Thermal development printing material (printed material) is disclosed in U.S. Patent No. 4.500.
, 354, the permanence and high-contrast printing performance of the recording paper not only provides controlled color development, but also the migration of substances within the printing material and the printing ink, fat, vinegar, and alcohol compositions. Manufactured in a single bath coating operation that also provides significant resistance to substances surrounding the packaged food product, such as moisture, or resinous materials from the labels of other packaging products that come into contact with the printed material of the present invention. It is possible.

In one aspect of the present invention, thermally developable printing ink and self-protective coating compositions are provided. The composition includes a chromogenic compound, a water-stable phenol-amine with limited solubility in water, an alkaline water-soluble binder, and a polyfunctional aziridinyl crosslinker for the binder. include.

In another aspect, the present invention provides a thermally developable environmentally friendly print comprising a paper or polymeric film coated with a mixture of a chromogen compound, a water-stable phenol-amine complex, and a multifunctional aziridinyl compound. Including materials.

In yet another aspect, the present invention provides that a polymeric film substrate or paper comprises a chromogenic compound, a water-stable phenol-amine complex of limited solubility in water, and an alkaline water-soluble binder. , a polyfunctional aziridinyl crosslinker for the binder, and subsequently the substrate coated in this way is dried. It consists of a single bus covering process.

(Example) Examples of the present invention will be described in detail below.

The chromogenic substances used in the compositions of the printing and self-protective coatings according to the invention are all color-forming substances which retain their white or colorless form until they react with the phenolic material under the influence of heat. . Various types of such chromogenic materials are described in U.S. Pat.
No. 097,288, as well as the other publications and patents listed herein, are known to include phthalic acid, naphthalic acid, fluoran, and spirobilan compounds.

Suitable and representative chromogenic materials for use in the present invention are fluorans such as:

3-N-cyclohexyl-N-butyl-6-methyl-7
-anilino/Fluoran 3-N-dibutylamino-7-lyloranilino/Fluoran 3-N-dibutylamino-7-fluoroanilino/Fluoran 3-N-dibutylamino-6-methyl-7-anilino/
Fluorane 3-N-cyclohexyl-N-methyl-6-methyl-7
- Anilino/fluoran 3-N-cyclomethyl-6-methyl-7-anilino/fluoran The above fluoran provides a black image. If a blue image is required for scanning with a blue laser, crystal violet lactone or a blue dye may be used.

The amount of chromogenic material is non-critical and is used in an amount of about 1% to 10% by weight of the total aqueous dispersion added to the printing material, or other amount that provides clarity and contrast. A preferred amount is about 3-6% by weight (wt.
%).

The phenolic resin component required for color development from chromogenic materials during thermal printing is included in printing inks such as phenol-amine complexes. This complex is a crystalline polymer formed by the reaction of a polyhydric phenol with a low-boiling amine, including both monoamines and polyamines. Phenol can form complexes with amines in aqueous media, and can also be used to form complexes with amines such as sulfonyldiphenol, thiodiphenol, 4.4'-dihydroxysulfonyldiphenol,
2,2°-hydroxysulfonyldiphenol, 4,4
Includes compounds such as °-dihydroxydiphenylolpropane, paraphenylphenol, etc., and mixtures thereof.

Typical amines are aliphatic primary or secondary amines.
or a mixture thereof, and the aliphatic group is alkyl or lower cycloalkyl ("lower" meaning 1 to 6 carbon atoms). Representative examples of such amines are n-butylamine, n-propylamine, cyclohexylamine, ethylenediamine, chlorine, soprobylamine, and the like. The phenol and amine are mixed in a 1:1 ratio to the amino group in the resulting complex.
The reaction is carried out in such a proportion as to contain hydroxyl groups in the above proportion. The ratio is preferably about 2:l, i.e. about 1
．． 9:1 to 2.05:lte.

The chemical formula of a typical phenol-amine complex is (HO-φ
−8o2−φ−OH)n(RNH2)y+, rf. φ is a substituted or unsubstituted phinidine group, and -n is 1 or more, for example from 2 to 30, preferably from 5 to 20.

R is an alkyl or cycloalkyl group such as n-butyl or cyclohexyl. Phenol-amine complexes such as those described above are described, for example, in U.S. Pat.
No. 354.

The phenol-amine complex is added to the aqueous dispersion in an effective amount to provide at least 1 equivalent for each equivalent of chromogen compound. However, an excess of phenol-amine complex is preferred to stabilize the chromogen compound and promote color resulting from thermal printing. For this reason, suitable aqueous dispersions contain a molar ratio of phenol-amine complex to chromogenic material of 1:1 or greater. This molar ratio is, for example, 1.5:1, preferably 2:1.

The third component of each printing and coating composition is an alkaline, water-soluble binder that promotes stabilization of the printing ink dispersion and binding of this component to the printing substrate. however,
Although the alkaline water-soluble binder can be dispersed in the aqueous printing composition and form a solid film on the printing material after drying, the durability contemplated by the present invention is not limited, as discussed below. It requires that the binder be crosslinked with the polyfunctional aziridinyl compound.

Alternatively, printing compositions may smear or degrade upon contact with moisture due to binder removal.

The binder materials used are natural substances such as casein and styrene-maleic anhydride copolymers, acrylic acid copolymers, styrene-butadiene copolymers, styrene acrylic copolymers, polyacrylamides, vinyl- including both acrylic copolymers or synthetic polymers such as polyesters, all of which react with polyfunctional aziridinyls,
It has a functionality that allows it to be crosslinked.

Generally, the crosslinkable functionality of the binder is a carboxyl compound, although some hydroxyl functionality serves as the basis for crosslinking. A preferred binder is casein or a styrene-maleic anhydride copolymer having a molar ratio of styrene to maleic anhydride of about 1:1 to 3:1. The functionality of the carboxyl compound of the binder described above may be partially esterified.

The binder becomes alkaline and water stable by reaction with an amine, ie, an alkali such as diethylamine or ammonium hydroxide. Preferred binders are ammoniated to form ammonia salts. Upon drying of the aqueous printing dispersion ink on the printing material, the ammonia or amine evaporates and the binder is crosslinked by the aziridinyl compound.

The binder is used in the aqueous dispersion in an amount of about 3 to 10 weight percent (wt%) based on total dispersion weight, preferably about 4.5 to about 6.5 wt%. Heavier materials such as cardboard will require higher binder concentrations.

Multifunctional aziridinyl crosslinkers (also known as polyaziridinyl compounds) are described in U.S. Pat.
．． No. 665 and No. 4,418,164, commercially available water-dispersible materials have the chemical formula:

Y is 10C-1R' is alkyl or hydroxyalkyl having 1 to 4 carbon atoms, and R' and 1 are each hydrogen or methyl. Typical compounds are as follows.

Trimethylolpropane-tris-[B-(N-aziridinyl)propionate-tocotrimethylolpropane-tris-[B-(N-2-methylaziridinyl)propionate-tocopentaerythritol-tris-[B-(N- [Aziridinyl)propionate] If other multifunctional aziridinyl compounds contain at least two groups that crosslink with the binder, i.e. two aziridinyl groups rather than the three aziridinyl groups of the compounds listed above.
Two aziridinyl groups may be used. Trifunctional compounds are available from “XAMA-2” and “XAMA-7” (Cordopa Chemical Company of Michigan, ((:ordova (
:chemical company of michig
an) and “CX-100” (Polyvinyl Chemical Industry, Polyvinyl (:hemic
It is used commercially under the name Al Indusj-ries).

The polyfunctional aziridinyl compound is used for crosslinking of the binder and this reason is about 3.2673.62 to 7.1473.
Up to 62 aziridinyl compounds/binder (milliequivalents/g
) is used in effective amounts because it is in the ratio.

The use of ratios lower than 3.2673.62 results in contamination of the printhead with binder and other residue.

The use of a ratio of 7°1473.62 or higher is
This produces an image that exhibits a significant loss of optical density.

A preferred ratio is about 3.473.62 to 3.7573.
62, particularly about 3.6273.62.

Optionally, other ingredients may be added to the aqueous dispersion to induce certain properties. For example, fatty acid amides are commonly added to such dispersions to modify the melting point of the dried printing ink composition. The main fatty acid amides include behenic acid amide, arachiamide, bisstearamide and mixtures thereof. Other additives used are fillers such as alkaline or alkaline earth metal fatty acid salts, solvents for phenolic developers and chromogenic compounds such as C,4-C2, aliphatic ketones, and dispersants. surfactants, optical brighteners, compounds for PH control, and potassium salts of polyester resins (“Arresat Kay 140”, to promote the prevention of the transfer of acidic substances from the printing material to the printing roughness). American Hekito Co., Ltd., "^1resat K-140", American Hoechst).

Aqueous printing dispersions are made by first dispersing a binder in an aqueous medium,
Add ammonium hydroxide to solubilize the binder, and optional additives like fatty acid amides, potassium carbide and aluminum hydroxide for pH control or crosslinkers or chromogenic compounds or phenol-amine complexes. A dispersion promoter, such as a surfactant, which is compatible with the other components of the dispersion, and a silicone-type defoaming agent are prepared by kneading the dispersion. If the coating composition is to be kept in storage for an extended period of time, it may be appropriate to add an aziridinyl crosslinker at the time of use to eliminate premature crosslinking. The printing material is coated with the aqueous dispersion by any suitable method, such as knife coating, direct metered reverse roll, Meyer rod coating, reverse gravure coating, or air knife coating.

Suitable printing materials include various types of paper (machine-sanded or machine-finished paper and cardboard) and polymeric films that are sensitive to thermal printing inks. Typical of the latter are films having a softening point of at least 200° C., such as polycarbonates and polyesters, such as polyamides, polystyrene, and copolymers of cellulose acetate butyrate butyrate.

After application of the printing ink dispersion, the coated substrate is dried in air or in an oven so that the binder material is crosslinked to form a highly protective heat-developable coating with the chromogen composition and phenol-amine complex. do.

In one method of use, the printing material of the invention is coated with a pressure-sensitive adhesive that is affixed with a release paper.

As a result, the paper or film is ready for thermal printing in the production of labels that are applied to paper or film packaging in inner packaging or other retail operations. In other applications, the printing material may first be thermally printed and then applied directly to the paper or film packaging with a suitable adhesive. In yet other applications, the printed material may be cured or further protected before or after printing.
It may be laminated to a backing material containing magnetic material or, after printing, it may be laminated to a backing sheet and/or transparent surface for protection of credit cards, access control cards, magnetic tickets, etc. The following examples further illustrate the invention but do not limit its scope.

All parts and proportions in the Examples and in the specification and claims are by weight unless otherwise indicated.

Medical-1 Aqueous printing ink and coating roughness are prepared from the following formulation. ! Phenol-amine complex (111,2) Behenic acid amide (211,0) Styrene-maleic anhydride copolymer, aluminum salt (3) 0.43-n-cyclohexyl-n-butyl-6-methyl-7 1-anirite fluorane (4) 0.2 polyaziridinyl crosslinker (s+ Q, 4 optical brightener 1B)
0.2-
5.6(1) A crystalline material obtained by reacting dihydroxydiphenylsulfone and n-butylamine at a molar ratio of 2:1.

(2) Chemamide B: Witco Chemical Corporation, Humco Chemical Division
e B:Witco Chemical (:orpo
ration,) Iumk.

Chemical Division).

(3) Scripsct 540 resin: Monsanto Kambani (isopropyl half ester) (Scripsct 5
40resin:Mon5anto Company
) (4) Shin-Hisso Kako (Shin-Hisso
(5) XAMA-2: Trimethylolpropane tris-(B-(N-aziridinyl)propionate).

Cordova Chemical Company of Michigan (Cardov)
a(:chemical Company of Mic
(6) Arctic White: Milton-Davis Com
pany) composition is obtained by forming the phenol-amine complex in water in a reactor equipped with an ultra-high-speed stirrer and then adding small amounts of silicone defoamer, styrene maleic anhydride resin and ammonium hydroxide. It will be done.

While stirring continuously, the behenic acid amide is added and the mixture is cooled to 65°C. The fluorane dye is then added and the mixture is sand-milled for about 0.5 hours to give a finely ground dispersion with an average particle size of 4-6 μm. The mixture is then filtered and the aziridinyl crosslinker is added.

Scale label material side (Scale 1abel fa
ce 5tock) was coated with the aforementioned composition on mechanically polished or machine-finished paper at a coating rate of 7-8" and coated for about 8-10 seconds at a temperature distribution of about 200°C to 65°C. This coated paper is obtained by open drying the coated material, which was subsequently disclosed in U.S. Pat.
The labels obtained according to No. 500.354, together with commercially used thermal paper, are tested for resistance to a variety of substances commonly encountered in supermarkets and meat packaging processes. U.S. Patent No. 4゜500.35 used for comparison
The chemical formula of No. 4 is as follows, and the ingredients are the same as the above formulation except for the footnotes.

11 parts phenol-amine complex 323 bihinamide 250 styrene-
Areic anhydride copolymer.

Sodium salt 1130 3-n-cyclohexyl-n-butyl-6-methyl-7
-Anilitus fluorane polyester resin, potassium salt 235 Deveolarizing agent' 14-20
water
14001 Script Set 501 Resin - Monsanto
Company (Scripset 501 resin-M
onsanto Company) 2 Arresat
Chi 140-American Hochist (Alresat k
-140-American Hoechsj) 3 Silicone A/B pressure-sensitive acrylic adhesive was applied to a sample of coated paper, and the sample was
- thermally printed on a vp barcode press. The optical density (hereinafter abbreviated as 0.D.) of the label sample was measured. The samples were then soaked in water for 24 hours, air dried, and optically measured again to determine the effect of water on print quality. 0. D.

=0 indicates completely black print quality, but lower 0,D
．． The value (reflectance) indicates good print quality. The scannability of the barcode was also determined by laser checking. The results are shown on the front surface.

Measurements of the background optical density in % b were made on samples of coated paper of the invention immediately after application of the pressure sensitive adhesive and after storage for 6 months.

These results were compared with water resistance tests as well as optical density measurements of samples from other sources. This data is shown in Table ■.

The optical density of the image of the label sample used as in the water resistance test and its background was measured, and the individual samples were then coated with vegetable fat and oil. After storing the samples for 24 hours, the optical density was measured again. Display the results■
Shown below.

For the dtX test, label samples were prepared with thermally printed barcodes as in the water resistance test.

The optical density (% reflectance) was then measured and the samples were adhered to plasticized polyvinyl chloride (PVC) packaging film. After 72 hours of contact, the optical density was determined again. The measurements were performed using the contrast ratio [(Percentcontrast sign
al), (PC:S)].

R1 is the reflectance of the background, and R2 is the reflectance of the barcode.

The results (Table ■) give the contrast ratio between the background and image symbols retained by the sample.

The label samples were prepared as in the water resistance test and the test was conducted in a similar manner using vinegar instead of water. Table V shows the results.

Resistance to Human Water (Tap) 1 having a pressure sensitive adhesive and a protective film on the back of the paper, another protective layer on the front of the paper, a heat developable printed skin and a third protective top layer Multilayer material.

As evidenced by the surface finish, the crosslinking agents in the printing ink/coating compositions of the present invention prevent image fading.

When compared to commercially available products, the label stock of the present invention exhibits an initial optical density that is approximately twice as high after immersion in water, as compared to approximately three times as much in the case of Vericor multi-layer products, and even more in the case of Pitney Bowes products. becomes.

Additionally, the laser scannability of the present invention is 100% compared to 0% for previous U.S. patented products and less than 100% for commercially available products.
% was retained. Therefore, the system of the present invention provided excellent protection against moisture even though it was a single coating.

``Leave''.

Resistance to migration of pressure sensitive adhesive (7), IF"-)Li' 0.05
0.09 maximum level surface 3; Gokubo q6 type pear "0.Q, 05 0.Q
9 maximum Ricoh LAV115 cannot be used
. , 14 or above Label material 1. See footnotes for front surface 2. Similar to that used for water resistance testing, but with acrylic pressure sensitive adhesive applied from a release liner.

The optical density in Table 1 is not visually noticeable from 0.05 to 0.09, and the drop from 0.07 to 0.14 is marginally noticeable, like gray. However, sufficient inhibition of adhesive migration for the products of the present invention was achieved with a single coat compared to multiple coats of the Ricoh product.

Resistance to vegetable oils and fats! The results for a multilayer thermal paper cover similar to Ricoh LAV 115 demonstrate the superiority of the label of the present invention, particularly in terms of the properties of a single layer in contrast to the multilayer systems of commercial products.

Resistance to migration of plasticizer from packaging film to label surface, contrast display rate (pcs) Honki Kurigosukeno'u' 80 67-74 National Patent No. 4.500.35465-75 59-
660,000 label stock? ;7; LAv115U6'''75-8560-70 The results in Table 2 show that for the label according to the invention a high initial contrast between the background and the image symbol and a high retention even on contact with the packaging film. , further proves that the printing ink/coating composition of the invention provides good protection against plasticizer migration.Compared to others, the initial contrast is good for Ricoh products. The contrast is slightly reduced upon contact with the film. This Ricoh product is similar to the product of the present invention but requires a multilayer protective coating.

Resistance to Vinegar The test results in Table V show that the image of the product of the present invention changes less than commercially available products upon contact with vinegar; This shows that it is effective.

The following Table 1 summarizes the contrast display percentage (pcs) and scannability of labels coated with the compositions of the invention described above and printed with bar codes on a Hobart VIS-VP printer. The printed label was tested as described above (a).
to (e), and were further made to resist various conditions such as ethyl alcohol and ultraviolet light. Scannability and percent contrast reflectance are excellent when compared to a control sample (paper coated with the same composition but unaffected).

■ Reflectance % L seed 1y Barcode % side Animal g Vegetable oil 100 19 78 79
Ultraviolet rays 100 16 87 81
Vinegar 100 29 8
:l 65 distilled water 100 26
87 70 plasticized pvc too
iti 84 a.

Ethylal 100 35 89 60
Call 596 Control Label 100 19 86 77
By Luther Check.

2 as defined in test (d) above.

Example 214 The following printing ink formulation was used essentially as in Example 1 and tested for resistance to various environmental conditions, scannability and reflectance, also essentially as in Example 1. It is similar to Ingredients are as in Example 1 except for footnotes. As shown in Table 1, the results show somewhat less resistance to water than the formulation of Example 1, but good resistance to other effects and good optical sensitivity.

(Margin below)' L-elephant 2 3 to weight part
4-phenol amino complex 1.2 1.2 1
．． 2-bihinamide 1.0 1.0
1. No. 07. ,v;2@"zyl>acid" 0.4
0.4 0.2 Styrene-butadiene latex --o,
2x1 Crystal Violet Rough. , 15-one-tone τ-lyaziridinyl crosslinker. , 4--XAMA-2
) Aqueous 5090 - 0,4 water-based
3- 0.2 - Clay (hexagonal) --0,2 Water 5.0 5.
0 8.0 Fluorescent whitening agent 0.2 0
．． 2 0.2 alkaline buffer (K) lcOa)
0.1 - -1 Polysa Canbani 4 (Polysa
r Company) 2 Cordopa Chemical Kanbani 3 Gelling agent
100100 too 25 19 28 70 7
7 65 vinegar 100100 85 39
29 40 60 65 55 Plasticized PVC100-
-23--70--Ultraviolet light (7 days) 100-- 2
3 -- 70 -- Water 95 --
35--65-1 (Effects of the Invention) According to the present invention, since the composition for thermal development printing is configured as described above, it can be used in thermally printed labels used for food products, etc. in various environments. It has excellent protection and durability against substances that may have a harmful effect on the label, and can clearly maintain the indicia of the label.

Claims (18)

[Claims] (1) Heat-developable printing consisting of an aqueous dispersion containing a chromogenic substance, a water-stable phenol-amine complex with limited water solubility, and an alkaline water-soluble binder of the ammonium or amine salt type. 1. A composition for thermal development printing, comprising a polyfunctional aziridinyl compound as a stabilizer for a binder. (2) The above aziridinyl compound has the structure ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and Y is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, R
The thermal development printing composition according to claim 1, wherein ' is alkyl or hydroxyalkyl having 1 to 4 carbon atoms, and R'' and R'' are each hydrogen or methyl. (3) The thermal development printing composition according to claim 2, wherein the aziridinyl compound is trimethylolpropane-tris-[B-(N-aziridinyl)propionate]. (4) The thermal development printing composition according to claim 2, wherein the aziridinyl compound is trimethylolpropane-tris-[B-(N-2-methylaziridinyl)propionate]. . (5) The thermal development printing composition according to claim 2, wherein the aziridinyl compound is pentaerythritol-tris-[B-(N-aziridinyl)propionate]. (6) The thermal development printing composition according to claim 1, wherein the aziridinyl compound is present in a concentration of 0.5 to 1 equivalent per equivalent of the binder. (7) 3 to 10% by weight of binder and 10% by weight without 3
The thermal development printing composition according to claim 1, characterized in that it has an aziridinyl compound. (8) The binder is a styrene/maleic anhydride copolymer,
2. The thermal development printing composition according to claim 1, wherein the aziridinyl compound is trimethylolpropane-tris-[B-(N-azinidinyl)propionate]. (9) A heat-developable environmentally friendly printing material comprising a copolymer film base or paper coated with the composition according to claim 1. (10) A thermally developable environmentally friendly printing material comprising a copolymer film base or paper coated with the composition according to claim 2. (11) an aqueous dispersion comprising a chromogenic material, a water-stable phenol-amine complex with controlled water solubility, and an alkaline water-stable binder of the ammonium or amine salt type; A thermally developable printing composition characterized by having a polyfunctional aziridinyl compound with a ratio of aziridinyl compound/binder (milliequivalents/g) from 3.26/3.62 to 7.14/3.62. A composition for thermal development printing. (12) The aziridinyl compound/binder (milliequivalent/
g) The thermal development printing composition according to claim 11, characterized in that the ratio is from 3.4/3.62 to 3.75/3.62. (13) The aziridinyl compound/binder (milliequivalent/
g) The thermal development printing composition according to claim 11, characterized in that the ratio is 3.62/3.62. (14) The aziridinyl compound has the structure ▲There are mathematical formulas, chemical formulas, tables, etc.▼, Y is -O-C-, R' is alkyl or hydroxyalkyl having 1 to 4 carbon atoms, R'' and R
12. The thermal development printing composition according to claim 11, wherein ``'' is each hydrogen or methyl. (15) The thermal development printing composition according to claim 14, wherein the aziridinyl compound is trimethylolpropane-tris-[B-(N-aziridinyl)propionate]. (16) The aziridinyl compound is trimethylolpropane-tris-[B-(N-2-methylaziridinyl)
15. The heat-developable printing composition according to claim 14, wherein the composition is a polypropionate. (17) The thermal development printing composition according to claim 14, wherein the aziridinyl compound is pentaerythritol-tris-[B-(N-aziridinyl)propionate]. (18) Claim 13, wherein the binder is a styrene/areic anhydride copolymer, and the aziridinyl compound is trimethylolpropane-tris-[B-(N-aziridinyl)propionate]. The heat-developable printing composition described in 1.