US 3359127 A
Description (OCR text may contain errors)
Dec. 19, 1967 H. MEYER ET AL 3,359,127
POLYAMIDE HEAT TRANSFER FOR LAUNDERABLE FABRICS Filed May 9, 1966 2 Sheets-Sheet l Dec. 19, 1967 H. MEYER ET AL 3,359,127
POLYAMIDE HEAT TRANSFER FOR LAUNDERABLE FABRICS Filed May 9, 1966 2 Sheets-Sheet 2 I ff POP Y SUP/0PM Harm/mmv ,QNGSWPID Arm arson/@usm V-P-l MMR/www5 /p /5 United States Patent O 3,359,127 POLYAMEDE HEAT TRANSFER FOR LAUNDERABLE FABRICS Hans Meyer, Lawrence E. Shadbolt, and Harold J. Stern,
London, England, assignors to Polymark Limited, London, England, a corporation of Great Britain Filed May 9, 1966, Ser. No. 575,478 Claims priority, application Great Britain, Oct. 14, 1960, 33,276/ 60 9 Claims. (Cl. 117-S.4)
This application is a continuation-impart of application Ser. No. 420,080 and now abandoned.
The present invention relates to the application of markings or decorative effects to articles or textile fabrics, for the purpose of securing highly resistant or virtually permanent markings or decorative effects. Such markings or decorative effects may be produced in one or more colours and may be utilised for example for instructions as to handling (i.e. care labelling)7 as trade or brand marks or for providing surface decorations.
The application of satisfactory decorative patterns or other markings to textile articles or fabrics may often involve considerable difficulty where it is desired that such patterns or markings shall be resistant both to laundry treatment and to dry-cleaning, particularly when such treatments are carried out in succession or at different times. These treatments may involve subjecting the article to hot aqueous detergent solutions and/ or to organic liquids such as are used for dry-cleaning purposes, for example white spirit, trichloroethylene and also mixtures of aqueous cleaning media with organic liquids, for exampie an emulsion of soap-containing water in an organic solvent such as perchloroethylene. A marking or decorative effect which is to be highly resistant or virtually permanent must moveover be resistant to abrasion, flexing, creasing, pressing and calendering. Furthemore, to be of practical utility it must be possible to apply these markings or decorative effects to a wide variety of different textile surfaces or finishes and to textile material formed of various textile products and colours, and in many cases they may have to be applied to finished articles.
The object of the present invention is to provide a method and means for applying such markings or decorative effects to textile articles or fabrics, the aim being to provide a marking or decorative effect which is highly resistant to mechanical influences and to any chemical or detergent media to which it s likely to be subjected and which remains effective throughout the useful life of the textile article.
Methods have been proposed or operated heretofore for producing markings or decorative effects on textile articles based on the use of label-like elements adapted to be caused to adhere to the textile article conveniently by the application of heat and pressure. In one such method an element is provided in the nature of a transfer in which case the marking or decorative effect is first applied to a temporary support from which it is transferred to a textile article by heat and pressure, but these known methods have suffered from the disadvantage that the print transferred to the article did not withstand more than a limited number of cleaning operations, and in particular laundry treatment and dry-cleaning operations applied in immediate succession or at different times.
For these reasons it has remained usual for permanent marking purposes to utilise separate labels which are sewn or otherwise mechanically fastened to the article.
The present invention relates to the production of permanent markings or decorative effects by means of a heatscalable transfer.
The present invention is directed to a heat transferable marking element or transfer for producing an identification marking, trademark device or like information-bearing marking upon a surface to be marked, which marking comprises a layer of a solubilised linear polyamide.
The polyamide compounds concerned are closely related to the compounds commonly known as Nylons, but which compounds are rendered soluble in a limited range of solvents by treatment with an aldehyde in a manner well-known in the art, as described for example in Patent No. 2,430,860 assigned to E. I. du Pont de Nemours & Co.
The starting product for the aldehyde solubilising treatment may be any of the polyamides specified in the said patent and in particular may be polyhexamethylene adipamide (note Example 1 of the said patent) or polyhexamethylene sebacamide (See Example 10 of said patent) or interpolymer of polyhexamethylene adipamide and polyhexamethylene sebacamide (Example 3 of the said patent). Such polyhexamethylene adipamide compounds are known commercially as Nylon 66, polyhexamethylene sebacamide compounds as known commercially as Nylon 610 and the inter-polymers referred to are generally referred to as Nylon 66/610. As a result of the solubilising treatment alkylol and/ or alkoxy alkyl substitution occurs, such as methylol and/or methoxy methyl substitution when employing for example formaldehyde and methanol. Materials suitable for the present purpose will have a degree of substitution lying within the range of 10% to 70% but preferred materials will normally lie within the range of 30% to 55% substitution.
Details of the preparation of solubilised polyamides for use in accordance with the present invention are explained in detail below and it should be noted that solubilised derivatives of polyhexamethylene adipamide are available on the commercial market for example under the Trademarks Zytel (Du Pont de Nemours Inc. U.S.A.), and similar products sold by Belding Chemical Industries of New York, and Maranyl (Imperial Chemical Industries Ltd., London, England). Suitable grades of material available under the above Trademarks include Belding Chemical Industries BCI Nylon types i819 and 829 and Maranyl type C. 109/P.
Products made soluble in a limited range of solvents in the manner described above are hereinafter referred to in general terms as solubilised linear polyamides and are soluble only in a limited range of solvents and specific solvent mixtures such as alcohols and water.
It should be noted that both the original starting products and the solubilised products derived therefrom should be classed as thermoplastic compounds on a strict definition basis, but whereas the solubilised compounds are soluble in a limited range of solvents, they can be readily converted into an insoluble form by the :action of heat and pressuree and optionally in the presence of a curing agent so that a compound similar to the original starting compound is formed after the heat transfer operation has been effected, resulting in the transferred marking or impression being given many of the properties of normal synthetic linear polyamides such as Nylon 66 so as to provide a transferred marking or impression which is chemically inert, wear resistant, and of extremely low solubility in aqueous detergent solutions or in the type of organic solvents likely to be used in the chemical cleaning of articles bearing such transferred impressions.
An important feature of the present invention is that a curing agent capable of promoting the formation of the highly insoluble form of the solubilised linear polyamide may be included in the transfer during the production thereof so that it is available as a curing agent to promote the formation of the non-soluble form of the polyamide during transfer. Such curing agents may be organic monobasic or polybasic carboxylic acids. Such curing agents are substantially inoperative to effect curing of the solubilised linear polyamide to any substantial extent at room temperature but are effective at the temperature required for the purpose of bonding transfers or similar marking elements to an article to be marked. Alternatively the ammonium or amine salts of such acids may be used, in which case the active curing agent -acid becomes available for curing purposes at an elevated temperature.
Such compounds hereinafter referred to as latent curing agents may in general be produced by combining a volatile amine wit-h any of the said acids. Such latent curing agents are inactive over a pH range of 5.5 to 7.
It is a surprising fact that such curing agents, including the free acids, can be incorporated in the heat transfer in production without seriously affecting the storage life of such transfers so that such transfers can be stored by the users ready for use. The essential component of the transfers, namely the solubilised linear polyamides, remains substantially unaffected, that is in the solubilised form, but when the marking is applied under heat and pressure to an article -which is to receive the marking, the organic acid curing agent becomes effective to promote formation of the non-soluble form of the synthetic linear polyamide, which thus forms a highly resistant impression on the article to be marked, which impression is thus substantially unaffected by :aqueous cleaning media or by solvent cleaning media such as may be applied during the life of the article for cleaning purposes, and thereby providing a means of producing a highly resistant marking on a textile article which remains effective throughout the life of the article.
A method of applying marking effects to a textile product such as a textile article or fabric according to the invention comprises applying a temporary support, a oontinuous layer of a solubilised linear polyamide and a printed informatiombearing pattern marking, both the layer and pattern marking being releasably carried by said support, said layer and said pattern marking being transferable to become permanently bonded to a textile article by heat and pressure exerted between the temporary support and the article, the temporary support being subsequently removed to leave the transferred layer and pattern marking on the marked article.
An opaque continuous layer may be used in some cases to provide -a background for the information-bearing marking, and such an opaque layer may be provided in addition to one or more transparent continuous layers. Thus a typical arrangement would include the continuous opaque layer on the outer side of the information-bearing marking, so that on transfer to the article said opaque layer forms a contrasting background for the pattern marking, and there may be a continuous transparent layer on the opposite side of the information-bearing marking to provide `a continuous protective layer on the exposed surface when the information-bearing marking has been transferred to an article to be marked.
Various embodiments of the invention are illustrated by way of example on the accompanying drawings in which: f
FIG. l is a front view of one form of transfer in accordance with the invention,
FIG. 2 is a partial crosssectional view taken on the line II-II of FIG. l,
FIGS. 3 to 8 illustrate in a manner similar to FIG. 2 various embodiments of the invention,
FIG. 9 illustrates the application of the transfer to an article and the subsequent stripping of the temporary support, using the transfer shown in FIGS. l and 2 of the drawings, and
FIGS. 10 and 1l are views corresponding to FIGS. l and 2 of a still further embodiment of the invention.
As shown in FIGS. l to S, l0 and ll, a temporary support 11 may consist for example of a suitable grade of paper coated with a suitable release agent, for example a mixture of an alkyd resin with an oil-soluble melamineformaldehyde resin. Alternatively, the support may consist of a material having inherent release properties. Such materials are for example polyethylene terephthalate, for example foils of the material known under the trademarks Melinex or Mylar or the support may consist of such foils attached or laminated to a sheet of paper, or it may consist of cellulose materials, for example regenerated cellulose or cellulose ethers or esters, in particular cellulose diacetate or triacetate.
In a further alternative arrangement the support may consist of a metal foil, for example of copper, this arrangement facilitating the transmission of heat to the transfer during the application to an article to be marked. In this case the metal foil may 4be provided with a layer of a suitable release agent such as a mixture of an alkyd resin with an oil-soluble melamine-formaldehyde resin, or it may consist of a layer of polyethylene terephthalate applied by lamination.
In FIGS. l, 2, 3, 4, lO and ll a decorative pattern or marking in the form of a discontinuous layer represented in typical form at 12, is produced on the said support by a suitable printing procedure, for example by silk-screen printing, utilising as the printing medium a solubilised synthetic linear polyamide consisting for example of one of the solubilised linear polyamide materials specified above. This printing medium is compounded from this material in a solvent and contains suitable pigment edia, as explained in greater detail below. In FIGS. l and 2 a continuous covering layer 13 is then applied which in this embodiment is capable of forming a background for the pattern marking 12 after transfer. This layer may be a transparent layer such as 13 in FIG. 2 or it may be an opaque layer such as shown at 131 in FIG. 3. A transparent coloured layer or an opaque layer is capable of providing a contrastingly coloured background for the pattern marking 12 after transfer and in al1 cases the outermost layer is capable of being bonded to an article to be marked.
FIG. 3 illustrates an arrangement comprising a temporary support 11, a printed pattern marking 12 thereon, an opaque layer 131 superposed on the pattern marking 12 and on the support 11, and an uppermost transparent layer 13.
FIG. 4 illustrates an embodiment in which a temporary support 11 carries a pattern marking 12 followed by a transparent layer 13 as in FIG. 2. This layer is followed by an opaque layer 131 in turn followed by a transparent uppermost layer 132.
By the term continuous there is meant a layer which is continuous over the whole of each transfer, but is not necessarily continuous over the whole area of the temporary support which may thus consist of a strip of material having successive transfer areas thereon, each transfer area comprising the continuous transparent layer 13 or similar translucent or substantially opaque layers 131. The layers 13 or 131 consist of a solubilised lineal' polyamide similar in character to the base medium from which the pattern or design 12 is formed, but applied in the form of a continuous covering layer by means of any suitable spreading or coating operation. Since both the design or pattern 12 and the covering layer 13 or 131 consist basically of a solubilised linear polyamide, which may both contain a suitable curing agent as specified below, a highly resistant decorative pattern can be formed upon the article to be marked. This design or pattern 12 may be produced in one or more colours and such transfers may be applied in a manner hereinafter eX- plained with reference to FIG. 9.
FIG. 5 illustrates another embodiment of this form of the invention where the temporary support 11 is initially coated with a continuous transparent layer 14 of a solubilised linear polyamide, and the decorative printed pattern or marking 12, also compounded from a solubilised. linear polyamide, is applied to the outer surface of this coating layer. On application of a transfer of this character to a textile article both the layer 14 and the pattern 12 itself are caused to adhere to the article. The layer 14 which in this case will normally be transparent, provides a protective covering upon the decorative marking and may be adapted to give a particularly pleasing effect.
FIG. 6 shows in section an embodiment wherein a pattern marking 12 is sandwiched between two continuous layers 13, 14 the whole being carried by a temporary support 11. Both these layers are preferably formed by using coating colutions of solubilised linear polyamide as above referred to and as described with reference to the following examples. Obviously the layer 13 may be opaque and contrastingly coloured in relation to the pattern marking 12, whereas the continuous layer 14 is transparent.
FIG. 7 illustrates an arrangement generally similar to FIG. 6 but where an additional opaque layer 131 is provided, the complete assembly including a temporary support 11, a continuous transparent layer 14 lbearing the pattern marking 12, an opaque continuous layer 131 and a continuous transparent layer 132.
As shown in FIG. 8 it is not necessary for all the layers of a sandwich assembly where a pattern marking 12 is sandwiched between continuous layers, to be formed of solubilised linear polyamide materials. In FIG. S the lowermost layer 141 may consist of a nylon foil initially attached to the temporary support 11, the printed pattern marking 12 being printed on the nylon foil layer 141.
Where a sandwich construction is used as in FIGS. 6 to 8 the printing of the pattern 12 may be produced by other printing procedures, for example by a flexographic printing process using the so-called flexographic ink products.
FIG. 9 illustrates as a typical example the application of the transfer shown in FIG. 2 to a fabric or other article 1S by the action of platens 16, 17, which press the complete transfer assembly into contact with the article, the platen 16 at least being heated to a suitable temperature. After heat and pressure have been maintained for a suitable period the platen pressure is released and the temporary support 11 may be stripped off leaving the pattern marking with any layer 13, 131, 14 0r 141 associated with it, adherent to the article 15.
The invention is not limited to the provision of a heat transfer including continuous layers such. as 13, 131, 14, 141, and FIGS. l and 1l illustrate embodiments in which the printed pattern marking 12 is produced upon the temporary support 11. This printed pattern may be produced for example as described under coating medium 1 below and it may be used in the manner shown in FIG. 9. The printed pattern marking then consists solely of the marking itself without any underlying or superposed continuous layer.
This invention will be further illustrated by the following examples which are preceded by a description of the preparation of a range of solubilised linear polyamide products by methods analogous to those described in U.S. Patent No. 2,430,860. The formulation of various coating media will then be described together with particulars of the various additives, particularly curing agents, which may be present.
The following preparations illustrate the production of solubilised linear polyamide products:
PREPARATION I.-PRODUCTION OF SOLUBI- LISED LINEAR POLYAMIDES FROM NYLON TYPE 66 STARTING MATERIAL In the following preparations the parts given are parts by weight unless otherwise stated.
5.0 parts of a finely divided fibre-forming polyhexamethylene adipamide are placed in a `stainless steel autoclave fitted with a stirring device. 90 parts methanol, 37.5 parts paraformaldehyde, and 1 part concentrated phosphoric aci-d are added. The mixture is heated, with stirring,
65 to a temperature of 125 C. and maintained at that temperature for 60v minutes.
After cooling the autoclave is opened and 600 parts of a mixture of by volume ethyl alcohol and 5% by volume water is added. Stirring is resumed and the contents of the autoclave warmed to about 45 C. When a homogeneous syrup has been formed, ammonium hydroxide is added in sufficient quantity to neutralise the phosphoric acid present. The warm syrup is then poured in a thin stream into a large volume (5 litres) of cold water with good stirring. The modified polyamide separates in the form of soft Whitish granules. These are separated by decantation, washed with several lots of cold water and finally dried in a current of warm air at a ternperature not exceeding 50 C.
PREPARATION IL PRODUCTION OF SOLUBI- LISED LINEAR POLYAMIDES FROM NYLON 610 STARTING MATERIAL 50 parts of a finely divided fibre forming polyhexamethylene sebacamide are placed in a stainless steel autoclave fitted with a stirring device. 80 parts methanol, 50 parts paraformaldehyde and 1.65 parts concentrated phosphoric acid are added. The autoclave is sealed, stirring commenced and the autoclave is heated to 130 C. It is maintained at this temperature for 45 minutes and then cooled to room temperature. 300 parts of a mixture of 75% methanol and 25% water by volume is added with stirring.
The solution is filtered to remove any incompletely reacted polyamide particles. The clear filtrate is neutralised with ammonia and the modified polyamide precipitated, by pouring into a large volume of cold water with good stirring. The precipitate is washed with cold water, separated by decantation and dried in a current of warm air.
As the particles are liable to coalesce, in the early stages of drying it is advisable to limit the drying temperature to a maximum of 35 C. which is raised gradually to a maximum of 50 C.
PREPARATION IIL- PRODUCTION OF SOLUBI- LISED LINEAR POLYAMIDES FROM NYLON 66/ 610 STARTING MATERIAL 50 parts of a finely divided fibre-forming interpolymer prepared from hexamethylene adipamide (3.0 parts) and r hexamethylene sebacamide (70 parts) is placed in a stainless steel autoclave tted with a stirrer. parts methanol, 60 parts paraformaldehyde and 1.3 parts concentrated phosphoric acid are added. The autoclave is sealed and the contents heated, with stirring, to C. and maintained at this temperature for 2 hours. The autoclave is cooled and 400 parts of a mixture consisting of 80 parts ethyl alcohol and 20 parts water by volume is added with stirring. The resulting solution, after filtration if necessary to remove any particles of insuiiiciently reacted polyamide, is rendered neutral by the addition of ammonia. The modified polyamide is precipitated, washed and dried in the manner described in the previous preparations.
The curing agents used are in general organic acids such as are set out in the following list and are present in an amount which may be determined `by making a preliminary test by adding the curing agent to a 5% solution by weight of the solubilised polyamide in an ethyl alcohol/ water mixture 70/ 30 (by volume) and determining the quantity of acid required to bring the pH value to a predetermined tigure, normal-ly pH 5 or less.
Preferably the amount of acid will be that required to bring the pH to a value of between 3.5 and 4.5 or more specifically between 4.0 and 4.2. Other curing agents which may be employed are latent curing agents which decompose to give acidic products at the temperature used for bonding the marking element or transfer to the surface of an article to be marked. Such compounds may be salts of organic acids, such for example as triammonium citrate, triethyl-ammonium citrate, di-ammonium hydrogen citrate or butyl acid phosphate which is a commercial mixture of n-butyl dihydrogen phosphate and di-n-butyl hydrogen phosphate. Such latent curing agents are substantially neutral at room temperature but yield acidic products at elevated temperatures. They may be produced in situ, for example triethyl-ammonium citrate may be produced by adding citric acid and triethylamine to the coating mixture.
In the case of such latent curing agents, salts or other compounds or mixtures which yield curing 'agents under the action of an elevated temperature, the amount present may have to be determined by trial and error but will be such as to establish a pH value of pH or :less at the temperature operative during the step of applying the marking element or transfer under heat and pressure to a surface to be marked. In general experience has shown that the amount of such latent curing agents should be such as to bring the pH value of the coating mixture to a value between pH 6 and pH 7.
In the formulation of transfers or marking elements according to the present invention solubilised linear polyamide layers are coated on a suitable support and comprise the polyamide, a solvent mixture consisting of an alcohol and water, a pigment in the case of a colour layer and a curing agent. The alcohol referred to is any alcohol which is miscible with water to an extent such that at least 14% of the total weight of the alcohol/ water mixture may consist of water, without the alcohol/ water mixture forming two separate layers. Such alcohols may be aliphatic alcohols such as methanol or ethanol or may be complex alcohols such as diacetone alcohol or isopropylidene glycerol.
If desired plasticising agents may also be present. The various coating media are compounded in such a way as to give a mixture capable of being spread on to a exible support by commercial coating methods and such coating compositions will in general contain components lying within the ranges specified below.
Parts by wt. Solubilized linear polyamide 5-25 Methyl or ethyl alcohol 60 Water -30 As indicated above, -a plasticiser .may also be present in which case about up to 10 parts by weight of a suitable plasticiser such as benzyl alcohol or N-ethyltoluenesulphonamide may be used.
In the case of a coloured layer or a pigmented layer, the amount of pigment may be between 10 and 100 parts by weight. The amount of curing agent present depends on the particular agent used and will be present in an amount not exceeding the quantities set out in the following list of examples, the percentage being in each case computed by weight on the amount of solubilised linear polyamide present.
Percent Citric acid up to 10 Aconitic acid up to 10 Phthalic acid up to 15 Salicylic acid up to 25 Tartaric acid up to 25 Tannic acid up to 30 Thiosalicylic acid up to 30 Alternatively latent curing agents such as those salts referred to above may be used, and if desired such agents may be employed in conjunction with any of the organic acids specied above.
The following yis a number of examples of representative coating compositions which can be used in commercial practice. It will be observed that various degrees of substitution of the polyamides are dealt with in the examples and in general it may be noted here that the greater the degree of substitution the greater the solubility and the greater the proportion of pigment which can be accepted by a pigmented coating medium. The following list represents typical coating mixtures in which coatings 1 to 8 are pigmented layers and 9 to 11 are clear layers. In each case the solubilised linear polyamide used is indicated by the Nylon Type Nos: N/ 616A referring to polyhexamethylene adipamide, N/610` referring to polyhexamethylene sebacamide and N/ 66/ 610 referring to the inter-polymers.
Coating Medium 1: Parts by wt. N66 (30% substitution) 12 Diacetone alcohol 60 Water 2() High quality carbon black 12.5 Citric acid 0.3
Coating Medium 2:
N610 (40% substitution) 5 N-butyl alcohol 60 Water 15 Titanium dioxide 10 Aconitic acid 0.05
Coating Medium 3:
N66/610 (37% substitution) 12.5 Iso-propylidene glycerol 60 Water 27 Titanium dioxide 70 Tartaric acid 0.325
Coating Medium 4:
N66 (45% substitution) 25 Diacetone alcohol 60 Benzyl alcohol (plasticiser) 7 Cadmium red 30 Water 27 Thiosalicylic acid 5.4
Coating Medium 5:
N66 or N160 or N66/6l0 20 (all 55% substitution) Diacetone alcohol 60 Water 30 Cadmium red 25 Citric acid 1 e Coating Medium 6:
N66, N610, N66/6l0 12.5
(all 40% substitution) Diacetone alcohol 60 Water 27 Titanium dioxide 5 Monastral blue 5 Triammonium citrate 0.7
Coating Medium 7:
N66, N610, -N66/610 (all 30% substitution) 7 Diacetone alcohol 60 Water 20 Monastral blue 5 Citric acid 0.14
Coating Medium 8:
Phthalic acid 0.39
9 Coating Medium 11: Parts by wt. N66, N610, N66/610 (all 45% substitution) 22.5
1 To give a pH value of 6 7.
It will lbe understood that the above coating media represent typical compositions suitable for use in the present invention and are only intended as examples of suitable coating layers. As already indicated, a Wide range of curing agents may be present which in the case of coating media 1 to 5, 7 to 10 consist of organic acids which become effective as curing agents at the temperature utilised for bonding the marking element or transfer to the a-rticle to be marked. Coating media 6 and 11 on the other hand include latent curing agents.
The pattern marking utilised in accordance with the present invention, particularly in relation to the embodiments of the invention shown on the drawings except in the case of the sandwich construction of FIGS. 6 and 8, is produced by printing operations using a printing medium which may be pigmented coating media similar to media 1 to 8 specified above. Another composition suitable as a printing medium may be as follows:
Printing medium: Parts by wt.
P-rintin-g media for other colours may be compounded on the same basis the pigment being replaced by other pigments (including car-bon black) in appropriate amounts.
The following examples illustrate several forms of heat transfer according to the present invention suitable for application to textile or other articles.
Example 1.--This example illustrates a construction corresponding to that shown on FIG. 3 of the drawings. A temporary support 11 consists of a tough exible paper such as that commonly known as DaC. 361b bleached kraft paper and having a thickness of about .0035 is laminated to a thin foil consisting of polyethylene terephthalate such as the material known under the trademarks Melinex or Mylan This foil may be about .0005 thick .and may be bonded thereto by any suitable adhesive. A printed pattern or design 12 is then applied to the foil surface produced with one of the pigmented coating media or the printing medium specified above.
The desired pattern is printed by screen printing and the mesh of the screen may be varied according to the thickness of the ink layer required. After application of the printing medium the coating is allowed to dry at room temperature.
The dried thickness of the pattern produced may be of the order of 0.0003.
An opaque layer 131 is then applied over the Whole area of the transfer so as to cover the printed pattern. This opaque layer may consist of any of the coating media 1 to 8 above. This opaque layer is applied by screen printing so as to give a dried thickness of about .0005.
Then a transparent lacquer layer 13 consisting of any of the coating 4media 9 to 11 is applied over the whole transfer area. This layer is allowed to dry at room temperature to give a total thickness of 0.0015" and the resulting product is a heat transfer, and it may be produced in the form of .a sheet containing a plurality of separate transfer elements, from which individual transfers ready for use can be cut, or it may be in the form of a continuous strip. 4It will be noted that each coated layer 12, 131 and 13 includes a small proportion of curing agent which promotes conversion of the solubilised nylon to an insoluble form when the heat transfer is applied to an article to be marked under the action of heat and pressure.
Example 2.-This example illustrates a construction cor-responding to that shown on FIG. 6 of the drawings. In this example a laminated support :such as defined in Example 1 is first provided with a coating 14 of transparent lacquer, such as any of the coating media 7 to 9 but coated to give a dried thickness of .0005. Then the required pattern is printed by screen printing, the printing medium being as specified above, and Ifinally a transparent layer 13 is coated on the exposed surface to a total thickness of 0.0015.
A transfer produced according to Example 1 will show the information marking against a dark and opaque background, whereas in the case of Example 2 the marking is visible against a transparent background through which the colour of the surface of the article will appear and will of course show as a light background when the transfer is applied to a light colour arti-cle. In Example 1 the information marking is exposed on the outer surface, whereas in Example 2 it is protected by a further continuous layer.
Example 3 This example illustrates a construction corresponding to that shown on FlG. 4 of the drawings. A temporary support 11 of the character defined in Example 1 receives a printed information-bearing marking 12 the printing medium being yas specified above, and then there is applied a thin transparent coating 13 of coating media 9 to 11 but having a thickness of .0005". Then an opaque white layer 131 is applied consisting of coating medium 3. This layer is coated to a thickness such as to give -a dried thickness of .001". Finally a transparent lacquer layer 132 consisting of any of the coating media 9 to 11 is applied to give a dried thickness of .001" (or a total thickness of 0.0025).
Example 4.-This example illustrates a construction corresponding to that shown on FIG. 7. A temporary support as defined in Example 1 is provided with a first layer 14 of any of coating media 9 to 11 but such `as to give a dried thickness of .0005, and is thereafter followed by the printing pattern 12 produced with the printing medium above, followed by an opaque layer 131 formed from any of the coating media 1 to 6, followed by an outer coating 132 of transparent lacquer (coating media 9 to 11).
Example 5.-'l`his example illustrates a construction corresponding to that shown on FIG. 2 of the drawings. A temporary support 11 as defined in Example 1 is provided with an information-bearing marking 12 produced with a printing medium such as deiined above, and is then provided with either a transparent layer 13 (coating media 9 to 11 or with a continuous opaque layer 131 (coating media 1 to 8), such outer coatings being such as to give a dried thickness for this layer of .001.
Example 6.This example illustrates a construction corresponding to that shown on FIG. 5 of the drawings. A temporary support as defined in Example 1 is provided with a transparent layer 14 of any of the coating media 9 to 11 to give a dried thickness of .0005 and an information marking is printed thereon using the printing medium defined above.
Example 7.-This example illustrates a construction corresponding to that shown on FIG. 10 of the drawings. A temporary support as defined in Example 1 is provided with a pattern marking produced -by using the printing medium specified above. There is however no continuous coating on either side of the information marking and consequently the material transferred to an article to be marked consists exclusively of the pattern marking as described for example with reference to FIG. 1 of the drawings.
Example 8.-In this example the design is printed using a flexographic method, the layer construction of each transfer being basically that shown in FIG. 8. A reel of foil of polyethylene terephthalate of about 0.00 thick- 11 ness, forming a temporary support, has applied to it a clear coating of any of the coating media 9 to 11 to a thickness of about 0.001" using a normal roller coating process.
A design is printed on this last coating by flexographic means in which rubber stereos having the design cut in relief in their surfaces are applied to a roller and the ink is transferred from a source of ink to the coating by means of the roller mounte-d rubber stereos or by gravure or lithographie printing methods in either case by wellknown procedures. A normal ink Iwith an alcohol soluble binder such as shellac is used except that the pigment should be capable of withstanding the treatment to which the applied transfer will be subjected. For example cadmium red or monastral blue are suitable pigments. A thin clear coating (coating media 9 to 11) is then applied as before to the printed design to complete a sandwich-type transfer.
In the application of heat transfers according to the foregoing examples a press is used having a vertically movable top platen heated to a temperature ranging between 100 C. and 250 C. but preferably of the order of 200 C. and a lower fixed platen, covered with a suitable resilient heat-resistant material, either unheated or heated to a temperature between 100 C. and 200 C. and preferably of the order of 150 C. The pressureexerting means operative upon the top platen is such as to provide a specific pressure of from 25 to 75 lbs. per square inch but preferably about 50 lbs. per square inch. An article, for example, a textile article, with a transfer placed on the upper surface thereof is positioned between the two platens and then pressure is exerted by the top platen, the pressure being maintained for a period ranging from 1 to 5 seconds or preferably between 1 and 8 seconds. The maximum resistance of the transfer to rubbing and cleansing operations is obtained where, under the conditions specified, the time of treatment is 5 to 8 seconds but adequate resistance for many purposes is obtained even if the pressure is maintained for a shorter period down to about 1 second.
The degree of resistance to rubbing and cleansing operations depends to some extent upon the construction of the heat transfer chosen. For example comparatively light and delicate articles which may be subjected to moderate rubbing and cleansing throughout the effective life of the article may be of the relatively simple construction shown for example in FIGS. 1 to 5, l0 and 11, whereas articles which are subjected to heavy wear and frequent intensive washing or cleaning operations may require the sandwiched constructions of transfer such as are shown in FIGS. 6 to 8 of the drawings, and furthermore the nature of the coating layers and of the printing medium may be selected according to the nature of the article and the probable treatments to which it will be subjected during its working life. Again by way of example, an industrial type overall which is likely to receive heavy wear and to require frequent intensive washing operations could utilise thicker layers 13, 131, 14, 141 than in the case of transfers intended to be attached to delicate articles, while furthermore the proportion of acidic curing agent may be increased or an additional curing agent may be applied at the time when the transfer is attached to the article by the action of heat and pressure.
Thus for example the temperature and pressure figures may be varied according to the nature of the article which is to receive the transfer; for example in the case of synthetic fibre fabrics the temperature of the top and bottom platens may be reduced to 180 C. and 150 C. respectively and the pressure reduced to 25 lbs. per square inch with a corresponding increase in the time of maintenance of the pressure. By modifications of this character it becomes possible to apply the transfers defined herein to textile articles or garments formed of nylon thus providing the possibility of obtaining a marking bonded to a nylon garment which marking also consists of a type of nylon.
It will be observed that in all the embodiments of the present invention the part of the transfer or label which is brought into adhering contact with the textile article consists of a solubilised linear polyamide and examples of such materials are referred to above. An important feature of the present invention is that as a result of the application procedure under the action of heat and pressure this solubilised polyamide is converted into a form in which it becomes resistant to mechanical and chemical influences, and this conversion may be promoted by the use of a curing agent which is preferably a solid organic acid, as explained below.
A printed pattern or design 12 when produced by using a printing medium containing such a solubilised linear polyamide or with a continuous layer 13 or 14 as in FIGS. 1 to 7, is highly inert and resistant, as described above.
The inclusion of curing agents such as solid organic acids in the transfer during the production of such transfers is a considerable advantage in that the application procedure involves less complication than in cases where the transfer or the article must be treated with a solution of a curing agent as a separate operation immediately before or after the transfer is subjected to heat and pressure to cause the identification marking to be transferred to the article. Surprisingly it has been found that the inclusion of a solid organic acid of the character defined above does not adversely affect the storage life of transfers incorporating such acids, which transfers can consequently be produced and stored without serious risk of premature conversion of the solubilised linear polyamide to the insoluble form. Such transfers when applied under heat and pressure rapidly become converted, in contact with the article to which the transfer has been applied, into the insoluble form.
The use of a separate curing agent treatment may however be necessary under certain conditions so that insolubilisation may take place in a shorter time or at a lower temperature by using stronger acids than citric acid. The use of stronger acids is advantageous when dealing with fabrics which are liable to be damaged by high ternperatures, such as acetate rayon. Since such marking elements would have too short a storage life if the acid were incorporated in the marking element, it may be preferable to apply at least a part of the curing agent as a separate operation after the element has been applied to the textile article. Such secondary operation may conveniently be carried out by interposing a piece of cloth moistened with a curing agent between the marking element and a heated presser member, and by means of this heated presser member applying a further heat treatment to the assembly for a suitable period of time, beyond that required to provide adhesion.
It will be noted that the outermost layer or layers which are bonded to the article always comprise a solubilised linear polyamide, other layers may be of the same material or of a different material; further that the discontinuous layer 12 is either formed of a solubilised linear polyamide or is sandwiched between two layers and may then consist of conventional types of printing medium.
What we claim is:
1. A heat-sealable transfer for producing a permanent information-bearing mark on textiles comprising a temporary support and an information-bearing thermoplastic layer thereon, said thermoplastic layer being a solubilized thermoplastic polyamide taken from the group consisting of polyhexamethylene adipamide, polyhexamethylene sebacamide and inter-polymers thereof, said polyamide being 10-70% substituted by groups taken from the group consisting of alkylol and alkoxy alkyl substitution groups and combinations thereof and being soluble in a homogenous mixture of an alcohol and water, and a curing agent taken from the group consisting of citric acid,
r aconitic acid, phthalic acid, salicylic acid, tartaric acid,
tannic acid, thiosalicylic acid, the ammonium and amine salts thereof, and a mixture of n-butyl dihydrogen phosphate and di-n-butyl hydrogen phosphate and being present in an amount sufficient to maintain the pH of said thermoplastic layer upon being heated between 3.5 and 5, said layer being capable of being insolubilized and bonded to an article to be marked by heat and pressure.
2. A heat-scalable transfer as claimed in claim 1 wherein said substitution groups are taken from the group consisting of methylol and methoxy methyl groups.
3. A heat-scalable transfer as claimed in claim 1 wherein said substitution is Within the range of 30-55%.
4. A heat-sealable transfer as claimed in claim 1 wherein said temporary support is taken from the group consisting of polyethylene terephthalate, regenerated cellulose, cellulose diacetate, cellulose diacetate, cellulose triacetate and copper.
5. A heat-scalable transfer as claimed in claim 1 wherein said temporary support comprises paper with a release agent consisting of a mixture of alkyd resin and an oilsoluble melamine-formaldehyde resin coated on at least one surface thereof.
6. A heat-scalable transfer as claimed in claim 1 Where- 14 in the alcohol in said solvent mixture is miscible with water to the extent of at least 14% of the total Weight `of said mixture without the formation of separate layers.
7. A heat-sealable transfer as claimed in claim 6 wherein said alcohol is taken from the group consisting of methanol, ethanol, diacetone alcohol and isopropylidene glycerol.
8. A heat-sealable transfer as claimed in claim 1 Wherein said thermoplastic layer further comprises a pigment to give color to at least a portion of said heat-sealable transfer.
9. A heat-sealable transfer as claimed in claim 1 Wherein said pH range is between 3.5 and 4.5.
References Cited UNITED STATES PATENTS 1,966,942 7/1934 Atkinson 156-230 2,430,860 11/ 1947 Cairns 260-72 2,430,953 11/1947 Schneider 8-115.5 2,443,486 6/1948 Watkins 260-72 3.065.120 11/1960 Avelar 161-406 JACOB H. STEINBERG, Primary Examiner.