US3741787A

US3741787A - Dry decalcomania

Info

Publication number: US3741787A
Application number: US00151066A
Authority: US
Inventors: R Tordjman
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-08-07
Filing date: 1971-06-08
Publication date: 1973-06-26
Anticipated expiration: 1990-06-26
Also published as: DE1939824C3; NL6912087A; DE1939824A1; SE361628B; LU56664A1; JPS4910848B1; BE735735A; NL148548B; GB1260358A; FR2015193A1; DE1939824B2

Abstract

A PRESSURE-SENSITIVE DECALCOMANIA IS FORMED OF A SUPPORT SHEET CONTAINING A PLURALITY OF INDICIA WITH AN ADHESIVE COATING COVERING THE INDICIA AND THE ADJACENT SURFACE OF THE SUPPORT SHEET. SELECTED SOLVENTS ARE EMPLOYED IN THE ADHESIVE COATING FOR TRANSFERRING THE INDICIA TO A RECEIVING SURFACE WHILE RETAINING THE ADHESIVE COATING SURROUNDING THE TRANSFERRED INDICIA ON THE SUPPORT SHEET.

D R A W I N G

Description

June 1973 R. TORDJMAN 3,741,787

DRYIDECALOOMANIA v Filed June 8, 1971 '1 r r 4 3 Z 2a 1/ Y 2d INVENTOR ROGER TORDJ'MAN ma N??? United States Patent ice 3,741,787 DRY DECALCOMANIA Roger Tordjman, 78 La Calle, Saint Cloud, France Continuation-impart of abandoned application Ser. No.

ABSTRACT OF THE DISCLOSURE A pressure-sensitive decalcomania is formed of a support sheet containing a plurality of indicia with an adhesive coating covering the indicia and the adjacent surface of the support sheet. Selected solvents are employed in the adhesive coating for transferring the indicia to a receiving surface while retaining the adhesive coating surrounding the transferred indicia on the support sheet.

This is a continuation-in-part application of Ser. N0- 785,720 filed Dec. 20, 1968, now abandoned.

SUMMARY OF THE INVENTION The present invention relates to dry decalcomanias which do not require either water or heat for transfer to a. receiving surface and, more particularly, to pressuresensitive decalcomanias employing an adhesive coating containing two different solvents which assist in the transfer of indicia from a support sheet to the receiving surface.

t Preferably, the support sheet is transparent or translucent and may have a mat or shiny finish on one or both of its faces. On one of its surfaces, which is nonporous, a plurality of linked indicia, such as letters, numbers, symbols and the like, are deposited by a printing process, for example, offset, typography, seriography or heliogravure processes, and a pressure-sensitive adhesive coating is applied to the indicia and to the surface of the support sheet about the indicia.

Since, it is not practical to apply the adhesive coating only on the surfaceof the indicia, the coating is applied to the entire surface of the support sheet. Accordingly, it is necessary that the adhesive coating adhering directly to the non-porous surface of the support sheet be retained on the sheet at the time anindicia or number of indicia is transferred to a receiving surface. It can be appreciated that the transfer of additional adhesive coating to the receiving surface can interfere with its appearance or can have a tendency to collect dust about the periphery of the indicia."

When not being used for transferring indicia to a receiving surface, a protective sheet is applied to the surface of the support sheet containing the indicia to prevent any accidental transfer of the indicia. A protective sheet having a surface treated with silicon is effective forthis purose. g p To avoid transfer of the adhesive coating it has-been found to bepreferable-to use a'material which doesnot provide a sticky surface to the receiving surface, yet has a high degree of cohesiveness and a good bond with the .supportsheet. I

15 Claims Patented June 26, 1973 In previously known methods of transferring dry decalcomanias, the indicia have been removed by bending the support sheet, or alternatively, by providing a strong adhesive on the outer surface of the indicia. However these two transfer methods have their drawbacks, the first one risks damage to the indicia when they are bent at the same time that the support sheet is bent, and the second one risks accidental transfer of the indicia from the support sheet.

Therefore, it is a primary object of the invention to overcome the drawbacks previously experienced in the pressure sensitive transfer of decalcomanias and to provide a decalcomania which can be easily handled and transferred.

Another important object of the invention is to provide an adhesive coating for the transfer of the indicia to a receiving surface which embodies certain materials capable of assisting in the transfer of the indicia while maintaining the remainder of the coating on the support sheet.

Therefore, the invention provides improvements in the transfer of pressure-sensitive decalcomanias from a support sheet to a receiving surface by providing an adhesive coating over a non-porous surface of the support sheet containing the indicia with the adhesive employed assisting in the removal of the indicia from the support sheet due to a phenomenon of migration effected by solvents contained within the adhesive.

In the formation of sheets of dry decalcomanias, in accordance with the invention, a sheet, preferably formed of a transparent or translucent plastic material, is imprinted on a non-porous surface thereof with a plurality of indicia using a printing material such as ink or the like which has a low degree of adhesion or mechanical bond to the support sheet and has practically no chemical action with the support sheet. The molecules of the printing ink have an electro-chemioal charge of a certain polarity. In a polar liquid the electrical center of gravity falls outside the mechanical center of gravity. The negative charge is farther away from the core. With respect to electro-chemical charges in a material, reference is made to fTheory of Electric Polarisation, 1952 C. J. F. Bottcher, and Adhesion and Cohesion 1962 Philip Weis, page 3 (Elsevier Publishing Company). After the indicia are deposited on the sheet, a pressure-sensitive adhesive substance is coated onto the sheet covering all of the indicia and the adjacent surfaces of the sheet. The adhesive contains at least two solvents, one of which has an electro-chemical charge opposite in polarity to that of the electro-chemical charge of the printing material used in placing the indicia on the support sheet and, the other solvent is not provided with a charge which attracts it to the molecules in the printing ink. The first solvent, due to the opposite character of its charge relative to the charge on the printing material or ink forming the indicia, forms abond about the individual molecules of the printing substance and provides the body of material forming the indicia with a certain degree of porosity. Due to this porosity, the second solvent, since it is not attracted to the charges molecules of the printing material, infiltrates through the indicia and comes into contact with the surface of the support sheet under the indicia. The presence of the second solvent at the interface between the indicia and the support-sheet effects a reduction in the adhesion of the indicia to the sheet, because it contains a charge of the same character as the charge of the ink, so that the indicia which is mechanically but not chemically bonded to the support sheet can be easily transferred to a receiving surface by the application of pressure on the opposite surface of the support sheet. For providing an effective adhesive coating, the materials used to form the coating are specifically selected to aid in the separation of the indicia from the support sheet and to afford a shearing of the adhesive coating at the lateral peripheral boundaries of the indicia.

The migrating solvents, that is, the solvents passing through the indicia may contain other elements of materials for the following purposes.

(a) To reduce the adhesion of the indicia to the surface of the support sheet. It is possible to accentuate the proportion of the migrating solvent, or solvents, to obtain a total detachment of the indicia from the support sheet. Where the detachment of the indicia is complete and the layer of the adhesive coating is very thin over the indicia, it easily breaks around the peripheral boundary of the indicia permitting it to be completely separated from the support sheet. In some circumstances, this effect may be desirable, however, it does provide a considerable danger of accidentally transferring the indicia from the support sheet.

To prevent the likelihood of accidental transfer, the amount of the different solvents should be carefully proportioned whereby the bonding of the indicia to the support sheet is broken, but, the cohesiveness of the adhesive coating at the edges of the indicia is not sheared and, as a result, the indicia is retained on the support sheet.

(b) Where it is advantageous to do so, the migrating solvents may also include certain deactivating elements. These deactivating elements can effect a change in the adhesive quality of the coating covering the indici-a and provide it with a greater adhesive ability.

(c) Other elements may be incorporated in the migrating solvent to provide an effect on the surface of the indicia contacting the support sheet, that is, the outer surface of the indicia when it is transferred to a receiving surface. Therefore, a matting agent included 'in the adhesive material can provide a mat appearance to the surface of the indicia when the material infiltrates through the indicia to the surface of the support sheet.

When the support sheet has shiny surfaces, the effect on the matting agent can be particularly noted since it infiltrates through the indicia and becomes apparent through the surface of the support sheet at the interface with the indicia. Y

The various effects just described, attainable by mixin certain elements with the solvent which migrates through the indicia, can be obtained either separately or in combination by using the proper elements.

The following is a listing of the characteristics of the various members or parts which combine to form a dry decalcomania:

SUPPORT SHEET The support sheet has a non-porous surface on which the indicia are deposited and is formed of a material, preferably transparent or translucent, for affording good registration in the transfer of the indicia to a receiving surface. The surfaces of the support sheet can be dull on one or both sides or polished on one or both sides, while the thickness of the sheet can vary Within Wide limits ranging between 0.0010 to 0.010 inch."

To prevent the indicia from adhering strongly to the surface of the support sheet, it is important that the solvents used during the placement of the. indicia on the support sheet have the weakest possible interaction with its surface.

THE INDICIA The indicia are formed of a substance having ,good physical drying properties which form, after the evaporation of the solvents, a flexible film-like member on the support sheet. The indicia can be applied by any known method of printing or coating.

The printing materials employed in forming the indicia should form a weak or limited bond with the surface of the support sheet, therefore, it is not recommended that substances be employed in forming the indicia which would tend to adhere strongly to the support sheet. When the solvents in the subtsance forming the indicia have evaporated, a flexible film-like member is formed on the support surface which can be transferred as a unit to a receiving surface. In forming the indicia on the support surface, the substance used should be sensitive to the action of certain solvents contained in the adhesive material used as the coating since this characteristic is indispensible where the phenomenon of migration is employed.

The adhesive solution applied to the outer surfaces of the indicia on the support surface as well as to the remaining surface thereof is diluted with a combination of at least two solvents:

TYPE I SOLVENT The first or type I solvent carries an electro-chemical charge opposite to that impressed on the indicia and forms a film which covers or encloses and is, due to the opposite nature of the electrostatic charge, bonded to the indicia. The interaction of the first solvent and the indicia cause a swelling and the indicia develop a degree of p0- rosity which permits the infiltration of the second or type II solvents through the indicia. As the type I solventa ketone and/or glycol can be used.

TYPE II SOLVENT The second or type II solvent is not attracted to the substance forming the indicia and thus it is possible for it to infiltrate through the indicia to the interface shared with the support sheet. The second solvent can include a small percentage of a solvent which is attracted to the surface of the support sheet by reason of the pressure of opposite electro-chemical charges in the solvent and in the support sheet to facilitate the migration of the solvent through the indicia. However, the percentage of this additional solvent must be limited since too great an infiltration of the second solvent through the indicia would result in totally detaching it from the support sheet.

The type II solvents can serve as a vehicle or carrier for other elements mixed into the adhesive solution, and with which they are soluble. As the type II solvent aliphatic and aromatic compounds can be used.

By employing these different elements carried by the second solvent, it is possible to achieve different effects, based on the type of elements used, such as'providing a mat effect for the interface surface of the indicia, improving the adhesive character of the coating with the receiving surface, and affording total detachment of the indici from the support sheet, to name a few.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION THE DRAWINGS the support sheet and deposited on a receiving-surface; and

FIG. 4 is a partial sectional view illustrating the support surface containing several indicia encircled by the adhesive coating.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, an indicia 2 is shown imprinted upon a nonporous support surface 1, and while only one indicia is shown, it will be appreciated that the support-surface can contain a great number of indicia in a relatively closely spaced arrangement. The material forming the indicia is mechanically bonded to the non-porous support-surface, but it has practically no chemical action with the support sheet. After the indicia are formed on the support sheet, the adhesive solution 3 (FIG. 2) is deposited across the entire surface of the support sheet and a relatively thin layer 3' is superposed on the face of the indicia directed outwardly from the support sheet.

Infiltration of the solvents of the adhesive solution has caused the formation of a film as indicated at 4 between the support sheet 1 and the indicia 2.

In FIG. 3, the support sheet 1 is shown overlying a receiving surface 10. When the indicia 2 is being transferred from the support sheet 1 to the receiving surface 10, the support sheet or at least the adhesive coating 3, 3' is in contact with the receiving surface 10. By applying a pressure force in the direction of the arrows f, the adhesive coating 3 on the outer surface of the indicia is bonded to the receiving surface and the infiltration of the second solvent in the adhesive coating has provided a surface 4 of reduced attachment between the interface of the support sheet and the indicia so that after the pressure has been applied to the support sheet, the indicia adheres to the receiving surface and separates both from the surface 4 of the support sheet and from the adjoining coating 3 on the support sheet.

The ability of the indicia to separate from the enclosing portions of the adhesive coating disposed about its peripheral boundaries is explained due to the high degree of adhesion of the coating 3 to the surface of the support sheet while within the boundaries of the indicia, the solvents have combined to provide a separation of the indicia from the opposed surface of the support sheet. The reduced thickness of the coating 3' over the indicia 2 and the infiltration of the solvents through the indicia provide the required effect for achieving a clean shear or rupture action between the different portions of the adhesive coating 3, 3'.

In FIG. 4, the manner in which the different solvents within the adhesive coating 3 act is shown in a schematic arrangement in which the hatched parts 2a designate the molecules of the indicia and the open circles 5 define the molecules of the first or type I solvent which are attracted and bonded to the molecules of the indicia. Disposed outwardl'y" of and between the molecules and the molecules of'the'first solvent 5 are molecules 6, shown by solid circles which infiltrate between the molecules 2a of the indicia and contact the surface or interface the indicia and the support sheet 1. The openings between the molecules 2a of the indicia indicate the porosity afforded by the interaction of the-indicia and the first solvent which permits the second or type II solvent to pass into contacting relationship with the surface of the support sheet.

THE ADHESIVE SOLUTION After it has dried, the adhesive solutioncoated on the surface of the support sheet 1 and on the indicia 2 provides a pressure-sensitive coating for the subsequent transfer of the indicia to a receiving surface 10... H

In the selection of theadhesive materials, it isnece's'; sary to use materials which have. a good adhesion to; the surface of the support sheet. It is desirable that the pressure-sensitive adhesive be more .stronglybonded' to the surface of the support sheet 1 than to the surface of a receiving member 10, and it is preferable if the adhesive material has a relatively low sticking power so that in the step of transferring the indicia to the receiving surface 10, the remainder of the adhesive coating 3 remains on the support sheet and is not transferred over to the receiving surface.

Another factor to be considered is the cohesiveness of the coating 3, 3', which must be sufficient to hold the indicia on the support sheet yet permit the shear between the coating 3 on the sheet and the coating 3' on theindicia. For this reason, the use of wax in large proportions in the adhesive solution is to be avoided. However, if the cohesive force of the adhesive coating is not carefully balanced and the cohesive force between the different parts of the coating 3, 3' is great it may not be possible to effect a proper transfer of the indicia from the support sheet 1 to the receiving surface 10.

The cohesive character of the

coating

3, 3 should be such that it will permit thedetachment of the indicia 2 from the support sheet 1 by a shearing action about the laterally peripheral boundaries of the indicia. The shearing effect can be facilitated about the edges of the indicia by accenting the'detachment of the indicia by means of the phenomenon of migration.

An effective shearing of the adhesive coating 3 from that portion of the coating 3' on the indicia is possible by providing a substantial infiltration of the second solvent through the indicia to the surface of the support sheet 1. However, care must be taken to prevent the accidental transfer of the indicia from the support sheet.

It will be appreciated that the role of the adhesive coating is to retain the indicia on the support sheet until it is transferred by a pressure action to a receiving surface and then it is important for the adhesive coating to separate in a clean line about the lateral periphery of the indicia.

The duty of the adhesive layer in the present invention actually is, in the first part to retain on the support sheet the indicia released from the surface of the support sheet by the infiltration of the solvents and, in the second part to attract the indicia and secure it against the receiving surface.

To avoid any accidental transfer of the indicia, it is recommended that the adhesive coating have a relatively dry, non-sticky nature on its surface exposed to the receiving surface.

When the indicia 2 is applied to the support sheet 1, it has a certain degree of bonding to the support surface prior to the coating with the adhesive solution. When the adhesive solution is deposited on the surface of the support sheet, the infiltration of the type II or second solvent through the indicia effects a loosening of the bond between the indicia and the support sheet at the interface surface 4. It is not considered good practice to employ an adhesive having a high adhesive or sticky nature, but it should be capable of attaching and fixing the indicia to the receiving surface in the transfer operation. The ad hesive nature of the coating should be proportional to the ability of the indicia to adhere to the support sheet. Accordingly, the greater the adherence of the indicia to the support sheet, the greater should be the adhesion between the indicia and the receiving surface by means of the adhesive.

By employing the present invention, it is possible to achieve transfer of indicia from a support sheet by utilizing adhesives which have a low degree of adhesiveness and as a result improves the utilization of the product.

The following are examples of practical application of the invention indicating the various materials and substances used in forming the pressure-sensitive decalcomanias, inthese examples of the-ketones and glycols are the-type Isolvents and the aliphatic and aromatic compounds arethe type II solvents.

(I) Case of a support constituted by a sheet of polyvinyl chloride (a) Composition of the indicia: Solution of polystyrol in an aromatic solvent with a boiling range of 160 to 190 C.; in order to obtain a black indicia the solution can be colored by a pigment constituted by carbon black.

(b) Composition by weight, of the adhesive:

Polyvinyl ether with low viscosity 3.2. Polyvinyl ether with high viscosity 5.0 Wax with polyethylene base, with low molecular weight 0.4 Silica powder 2.6 Aliphatic hydrocarbon with a boiling range of 155 to 195 C., e.g. white spirit 50.00 Aliphatic hydrocarbon with a boiling range of 66- 70 C. 20.00 Glycolic ether with a boiling range of 132136 C.,

e.g. ethylene glycol monomethyl ether 9.9 Cyclohexanone 8.9

(II) Case of a support constituted by a sheet of polystyrene (a) Composition of the indicia: Ink with plastified nitrocellulose base, colored with carbon black in the case of a black ink.

(b) Composition, by weight, of the adhesive:

It will be appreciated that the examples set forth above are provided by way of explanation and not limitation.

What is claimed is:

1. A dry decalcomania comprising a support sheet, at least one indicia being formed of a printing ink and deposited on said support sheet, said printing ink having a mechanical bond to said support sheet but practically no chemical action with said support sheet, and a pressuresensitive adhesive substance being applied in the form of a solution to and forming a coating on said support sheet bearing said indicia, said adhesive coating completely covering said indicia and extending laterally therefrom over said support sheet, said printing ink having mole cules with electrochemical charges of a given polarity, said solution of the adhesive substance comprising at least one solvent with electrochemical charges of a polarity opposite to the polarity of the charges of the printing ink whereby said first solvent is attracted to the printing ink forming said indicia and adheres about the printing ink while imparting to it a degree of porosity, said solution of the adhesive substance comprising at least one further solvent the molecules of which do not comprise any electrochemical charges of a polarity opposite to the polarity of the charges in the printing ink, whereby said second solvent infiltrates through said indicia due to the degree of porosity achieved by its interaction with said first solvent and effects a reduction in the adhesion of said indicia to said support sheet.

2. A decalcomania, as set forth in claim 1, wherein said support sheet is formed of a material of such a nature that it is possible to see through said sheet from the surface opposite-the one bearing the indicia for obtaining proper registration in transferring said indicia to a receiving surface.

3. A decalcomania, as set forth in claim 2, wherein said support sheet has a thickness in the range of 0.010 to 0.001 inch.

4. A decalcomania, as set forth in claim 3, wherein said sheet is formed by one of polyvinyl chloride or polystyrene.

5. A decalcomania, as set forth in claim 1, wherein the printing ink of said indicia comprises a substance be ing arranged to dry on said support sheet to provide said indicia with a flexible film-like form capable of being removed as a unit from said support sheet.

6. A decalcomania, as set forth in claim 5, wherein said substance comprises a solution of polystyrol in an aromatic solvent having a high boiling point.

7. A decalcomania, as set forth in claim 5, wherein said substance comprises an ink with a plasticized nitrocellulose base.

8. A decalcomania, as set forth in claim 1, wherein said adhesive coating in contact with said support sheet has a greater adhesive bond with said support sheet than with a receiving sunface whereby the transfer of the adhesivecoated indicia from the support sheet to the receiving surface is effected while the adjacent adhesive coating remains secured to the support sheet.

9. A decalcomania, as set forth in claim 8, wherein said second solvent includes a small amount of a solvent having an attraction for said surface of said support sheet for facilitating the migration of said second solvent through said indicia.

10. A decalcomania, as set forth in claim 8, wherein said adhesive substance contains agents mixed with said first and second solvents for increasing the adhesiveness of said indicia to said receiving surface.

11. A decalcomania, as set forth in claim 10, wherein an agent is included in said adhesive substance for eifecting a mat-finish on the outwardly facing surface of said indicia when transferred to a receiving surface.

12. A decalcomania, as set forth in claim 1, wherein said adhesive coating has a composition by weight as follows:

13. A decalcomania, as set forth in claim 1, wherein the composition by weight of the adhesive coating is as follows:

Polyvinyl either with low viscosity 3.0 Polyvinyl ether with high viscosity 5.6 Wax with polyethylene base with low molecular weight 0.4 Silica powder 3.0 Aliphatic hydrocarbon with a boiling range of C. 54.0 Aliphatic hydrocarbon with a boiling range of 66- 70 C. 22.0 Glycolic other with a boiling range of 132- Total 100.00

14. A dry decalcomania for transfer without the use of Water or heat, comprising a support sheet having a non-porous surface formed by at least a coating of a plastic material thereon, at least one indicia being formed of a printing ink having an electrochemical charge and deposited on said support sheet, said printing ink having a mechanical bond to but practically no chemical action with said support sheet, and a pressure-sensitive adhesive substance being applied in the form of a solution to and forming a coating on said support sheet bearing said indicia, said adhesive coating completely covering said indicia and extending laterally therefrom over said support sheet, said printing ink having molecules bearing electrochemical charges of a given polarity, said first solution of the adhesive substance containing at least a first solvent consisting of at least one of a ketone and a glycol bearing an electrochemical charge of a polarity opposite to the polarity of the electrochemical charge on the printing ink forming said indicia and adheres about the molecules of the printing ink imparting the indicia wth a degree of porosity, said solution of the adhesive substance containing at least a second solvent consisting of at least one of an aliphatic and an aromatic compound which does not comprise an electrochemical charge of a polarity opposite to the polarity of the charge on the printing ink,

whereby said second solvent infiltrates through said indicia due to the degree of porosity achieved by the interaction of said first solvent therewith and effects a reduction in the adhesion of said indicia to said support sheet.

15. A dry decalcornania, as set forth in claim 14, characterized therein that said first solvent is formed of at least one glycolic ether with a boiling range of 132-136 C. and cyclohexanone and said second solvent consists at least of one of an aliphatic hydrocarbon with a boiling range of -195 C. and an aliphatic hydrocarbon with a boiling range of 66-70 C.

References Cited UNITED STATES PATENTS 3,298,850 1/1967 Reed et a1. 117--3.1 3,212,913 10/1965 Mackenzie 117-3.1 3,459,626 8/1969 Morgan 117-3.1X

WILLIAM D. MARTIN, Primary Examiner H. J. GWINNELL, Assistant Examiner U.S. Cl. X.R. 156-234; 161-406