PT91041B - PRODUCTION PROCESS OF A HEAT TRANSFERABLE LAMINATE - Google Patents

Abstract

An improved release system for heat transferable laminates wherein a transferable substrate (15) which contains a design layer (30) is transferred from a carrier web (2) onto an article such as a plastic bottle or container upon application of heat and pressure. The carrier web (2) includes a nonwax layer (5). The improved release system (5) includes a noncellulosic alkyd thermoset layer portion of the carrier web in contact with and adhered to a nonwax transfer layer portion of the transferable substrate (15). The improved release layer (5) is preferably a melamine modified noncellulosic alkyd which on curing exhibits thermoset properties. The transferable substrate transfers to the article upon application of heat to the carrier while the article contacts the laminate. The transferred substrate on the article is clear and exhibits improved scuff and abrasion resistance. The nonwax layer does not contain wax and may exhibit thermoplastic or thermoset properties.

Description

the present invention relates to the process of producing a heat transferable laminate, comprising a trans substrate. and a carrier sheet, for transfer from the carrier sheet to an article, by applying heat to the carrier sheet, when said article contacts the transferable substrate, characterized in that a support sheet is coated with a release layer not waxy, comprising a thermosetting alkyd resin, so as to form said carrier sheet, a non-waxy release layer that will be in contact with the said transferable substrate, which is obtained by coating, with an ink drawing layer, of a transfer coating, which will be in contact with said non-waxy release layer, if affixing said transferable substrate to the carrier sheet, after which said heat transferable laminate has the property, when a heat source is applied to the carrier, the said transferable substrate being in contact with the article, the transferable substrate separating completely of said non-waxy release layer and transfer to. for said article, said heat transferable laminate still having the additional property that no discernible portion of said non-waxy release layer is transferred to the article with said transferable substrate.

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-2 DESCRIPTIVE MEMORY

BACKGROUND OF THE INVENTION

1. Scope of the invention The present invention relates to a heat transferable label and an improved release composition for this purpose.

2. Description of prior art

The heat transferable labels of the prior art for printing designs on an article that typically involves decorative laminates consisting of a base sheet of paper or a carrier web coated with a wax or polymer release layer under which an ink drawing is printed.

U.S. Patent No. 9. 3,616,015 (Kingston) is illustrative of the prior art. In U.S. Patent No. 9. 3 616 015 a label carrier web, such as a sheet of paper, includes a heat transferable label, having a wax release layer affixed to a surface of the sheet of paper and an ink drawing layer superimposed on the layer of release of wax. In the heat transfer labeling process for printing designs on articles the web bearing the label is subjected. heating and the laminate is pressed onto an article with the ink drawing layer making direct contact with the article. When the weft or sheet of paper is subjected to heat, the wax layer begins to melt and allows the design layer to be transferred to the article. A part of the released wax is transferred to the article with the image of the drawing. After transferring the design to the article, the sheet of paper is immediately removed leaving the design firmly attached to the surface of the article with the wax layer exposed to the environment. The wax layer thus serves two purposes, in that it provides the release of the transferable label from the web by applying heat to the web and also forms a transparent protective layer on the transferred ink design. After transferring the eti69 176

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- For an article, the transferred wax release layer is post-flared which produces an optically transparent protective layer on the ink drawing and improves the protective properties of the transferred release wax.

an additional step involving post-flaring is achieved by subjecting the transferred wax layer to high temperature gas jets either as a direct gas flame or as hot air jets to produce wax surface temperatures of about 1509C to 2Q09C over a period of sufficient time to re-melt the wax coating without substantially heating the article to which the label has been transferred. After cooling the remelted wax coating by means of ambient air or forced cooled air, the cooled wax layer solidifies to form a transparent and smooth protective coating on the ink drawing.

Although the heat transferable label disclosed in this reference, can be used to decorate a wide variety of different items, typically plastic bottles, there is a degree of fogging or verifiable halo on the transferred label when the transfer is made to transparent plastic materials, despite the use of post-flare. □ Halo effect is caused by transferring a part of the wax release layer from the paper carrier sheet to the article together with the ink drawing layer. Although the transferred wax layer has the beneficial effect of providing a protective coating on the transferred ink drawing, the nature of the wax coating is such that it determines some halo around the outer edges of the transferred ink drawing layer. Although the wax-based release layers produced optically transparent protective layers over the ink drawing and provided a high degree of protection for the transferred ink drawing, they are nevertheless subject to scratches and abrasion due to the inherent nature of the wax material.

U.S. Patent No. 9. 3 922 435 (flsnes) discloses a heat transferable plate which is directed towards replacement69 176

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-4 tion of the wax-based release layer by a non-waxy resin thus avoiding the halo effect that has always been associated with the use of wax-based compositions. Asnes refers to this type of release layer as a dry release since it does not transfer to the article with the ink drawing layer when heat is applied to the heat transferable laminate, when the laminate is in contact with the article. Asnes discloses an embodiment in which the release layer will coat a backing sheet and a printed varnish layer will coat the release layer and then a printed design layer will coat the varnish layer. A printed heat-activated adhesive layer reverses the design layer. Asnes reveals that one or both of the dry release layers and / or varnish layer may contain a thermosetting polymeric resin that will not melt after application of heat, such as that used in the typical heat transferable temperature limit, for example 1509C to 2309C (Col 9, lines 3-8). Asnes' work refers to a list of thermosetting resins, which are crosslinked resins, for the release layer, for which resins are preferably selected from the group consisting of acrylic resins, polyamide resins, polyester resins, vinyl, epoxy resins, epoxy acrylate resins, allyl resins and aldehyde resins (col. 5, lines 34-38). Asnes also mentions that the thermosetting resin for the release layer can also include copolymers of aminoaldehydes with styrenated or alkyds (col. 5, lines 44-46). Asnes also indicates that copolymers of hexamethoxymethyl melamine and cellulosic esters, preferably cellulose acetate butyrate or cellulose acetate, can give excellent results (col. 5, lines 51-54). Asnes also teaches that when the thermosetting resin or other resin is in the release layer, a preferred material for the varnish layer printed above is a cellulosic ester, such as cellulose acetate (col. 5, lines 55-58).

Although several chemical classes of resins have properties. thermosetting properties are mentioned by Asnes in the description in this regard, however it has proved to be a very difficult problem.

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-5 It is difficult to find a combination of a non-waxy thermosetting release layer and a varnish layer to coat it, which simultaneously satisfies the large number of properties that are required and sought after for heat transferable lights in today's market. The connection between the grindable release liner and the varnish liner must decrease significantly when heat is applied to the laminate so that the transferable portion of the laminate separates completely from the release layer without carrying any portion of the release with it. In current practice, it has proved difficult to find one with a combination of thermosetting resins for the varnish and release coating layer that avoid any discernible tearing of the release layer during the transfer of the ink drawing layer to an article during the heat transfer process. It has also proved difficult, with thermosetting release systems, to achieve a degree of brilliant and sharp image of the transferred ink drawing layer that is comparable to that achieved with conventional wax-based delivery systems. It has also been shown to be particularly difficult to achieve a smooth interface between the thermosetting release layer and the varnish coating layer at the exact moment of transferring the design layer and the varnish layer to the article. At the exact moment of the transfer, any imperfection in the degree of smoothness and continuity of the interface surface between the release layer and the varnish coating layer results in a decrease in the quality of the image brightness of the transferred design. In addition, the varnish coating must always resist penetration through the ink drawing.

It must also exhibit a high degree of clarity and a high degree of resistance to scratches and abrasion after being transferred with the image of the drawing to the receiving article. It has been a very difficult problem to formulate a non-zero delivery system that simultaneously exhibits all of these required properties.

Consequently, it is an object of the present invention to provide an improved non-waxy based delivery system for heat transferable laminates which allows for transfer

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-6 of an ink drawing image of a carrier frame for an article, in particular for a plastic article. It is an important objective to provide a delivery system that provides a protective coating on the trans ink drawing image. wound in such a way that the transferred image shows increased resistance to abrasion and scratches while maintaining a high degree of optical clarity.

It is a further objective to provide an improved delivery system and a heat transferable laminate for use in transferring a drawing image from a carrier web to a plastic article where the problem of the wax halo around a transferred image has been addressed. deleted. An object. The related vo is to provide an improved delivery system for heat transferable laminates which provides a protective coating for the transferred image that is also resistant to common solvents.

SUMMARY OF THE INVENTION

In achieving the foregoing and related purposes of the invention it provides a heat transferable laminate having an improved delivery system. The heat transferable laminate of the invention includes a carrier sheet, typically of paper and a transferable substrate affixed to the carrier sheet. The carrier sheet includes a non-pink thermoset release layer coated on the paper sheet. The non-waxy release layer is advantageously formed by crosslinking an alkyd resin with melamine to produce a thermosetting release. The non-waxy release layer is a non-cellulosic alkyl resin formed by the crosslinking reaction of an alkyl polymer with methoxy melamine, to produce the thermosetting release layer. The alkyd polymer used is preferably of the type formed by the product of the thermosetting reaction of a hydroxy-functional polyester with a drying oil. The preferred hydroxy-functional polyester is the copolymer of monoethylenically unsaturated monomers, such as a copolymer solution composed of 2-hydroxyethyl acrylate, lauri methacrylate69 176

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-7lo and styrene. Instead of the styrene component, methyl methacrylate or mixtures of styrene and methacryl may be used. methylate. The preferred polyester thus has the type and composition disclosed in U.S. Patent No. 9. 4 654 270, col. 3, lines 15-2Θ. The drying oil is typically safflower oil, but it can also be tung oil, linseed oil, castor oil, safflower oil, liquid rosin fatty acid, soybean oil, cottonseed oil, peanut oil, oil of castor and coconut.

When melamine, preferably hexamethoxymethyl melamine, is added to the alkyd polymer together with a suitable crosslinking catalyst the mixture is coated on the carrier paper sheet. The coating is then cured, for example by convective hot air. During curing, melamine becomes cross-linked with the alkyd polymer to form a highly desirable thermosetting release layer on the paper carrier. The applicant has found that distinctly superior properties are achieved when the release layer is formed in this way.

The transferable substrate portion of the transferable laminate is formed by a non-waxy varnish transfer layer, an ink drawing layer on top of the varnish coating transfer layer and a heat-activated adhesive layer on the ink drawing layer. . The transferable substrate is formed by coating each of these layers, one by one, starting with the varnish coating transfer layer over the thermoset release layer of the carrier web to form a composite laminate.

The thermosetting release of the type described above has proven to exhibit exceptional release properties with a number of different types of varnish transfer layers that can be both thermosetting and thermoplastics in nature. However, the applicant has determined that the aforementioned thermosetting release exhibits particularly favorable release characteristics with transfer varnishes whose main component is vinyl resins such as poly (chloride

Ó9 176 1Λ ό Q

-8 vinylidene), acrylics such as ethyl methacrylate or vinyl chloride and vinyl acetate copolymers or a polyester in particular a polyester which is a saturated linear aromatic polyester, preferably a modified polyethylene terephthalate.

As heat and pressure are applied by a heat source to the composite laminate in contact with an article, such as a plastic container, the transferable substrate completely frees itself from the carrier's thermosetting release layer and transfers to the article is typically a plastic bottle or container to be decorated. The heat source applied is typically a heated metal press or a heated press cylinder, having a surface temperature of about 14 DSC to 22 ° C. The release system of the invention has the property of applying the heat source to the exposed side of the carrier sheet, while the transferable substrate is in contact with an article, the transferable substrate is completely released from the carrier to the article without taking it with it any discernible portion of the thermosetting release layer. The delivery system also has the additional property that by transferring the transferable substrate no discernible portion of the varnish coating layer remains in contact with the thermosetting release layer. It is believed that such a complete separation between the thermosetting release layer and the varnish transfer layer, that no discernible portion of the two layers remains in the other, is a distinct improvement from prior art systems that attempted to use a thermosetting resin for the liberation. □ transferred substrate resulting in the article shows a clear transferred design image permanently adhered to the article. The image of the transferred design is protected by the varnish coating transfer layer which is also transferred to the article. The transferred varnish coating layer covers the design image and provides a transparent protective coating that provides a marked increase in the abrasion and scratch resistance of the transferred design image. The degree of abrasion resistance provided by the transferred varnish coating is greater than what has been achieved to date by the ICU. use of a wax-based release in contact with a door

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-9dor. Said strong protective coating also exhibits excellent resistance to attack by household alcohol and common solvents often found in cosmetics and toiletries.

The present delivery system of the invention has the additional advantage over the wax based delivery systems, of eliminating the halo effect of the wax around the edges of the transferred design image. The halo effect of wax eliminated by the present delivery system has long been associated with wax-based release formulations.

Another aspect of the invention is that it has been determined that the inclusion of a lubricating agent, in particular lecithin in the coating formulation before it coats the release layer, achieves the smoothness of the varnish coating surface after it has been transferred to the receiving item. Thus, when the lubricating agent is used, the applicant has found that a smoother, and consequently markedly brighter, transfer coating is obtained from the transfer to the receiving article. Indeed, since the transferred varnish coating forms a protective layer on top of the transferred design image, the design image appears noticeably brighter when the lubricating agent is used in the varnish coating layer.

BRIEF DESCRIPTION DQ DRAWING

Fig. 1 is an illustration of a preferred embodiment of the heat transferable composite laminate.

DETAILED DESCRIPTION

A preferred embodiment of the heat transferable laminate 7 of the invention, as illustrated in fig. 1, is composed of a carrier web 2 and a transferable substrate 15. The carrier web is composed of a support gap 10, typically of paper covered with a non-waxy release layer 5. The non-waxy release cane 5 is advantageously composed of an alkyd resin that is cured to produce a thermoendu resin

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-10recoverable. The transferable substrate 15, as shown in fig. 1, is composed of a varnish transfer coating 20 which is covered by an ink drawing layer 30 which is in turn covered by a heat-activated adhesive layer 40.

As heat is applied with a hot press or a hot press cylinder to the exposed side of the support sheet 10 while the adhesive layer 40 of the laminate 7 is in contact with a bottle or article to be decorated, the transferable substrate 15 separates. completely from carrier frame 2 and transferred to the article.

transferable laminate 7 of the invention has the property that the transferable substrate 15, during transfer to the article to separate completely the level termoendurec_í release layer 5 at the interface i without taking with it any portion of release layer 5. ^L ste result is achieved with the application of a heated press (not shown) to the exposed side of the support sheet 10, the heated press having an average surface temperature of about 140 ° C to 220 ° C, preferably between about 150 ° C and about 220 ° C. The term wax as used herein must have its definition from the normal dictionary as in G. Haiuley. The Condensed Chemical Dictionary, 10 ?. edition, Van Wostrand Reinhold Company. The thermosetting release layer 5 is a non-waxy layer as it contains no waxes.

The thermosetting release layer 5 is composed of an alkyd resin. The alkyl resin release layer 5 is formed by coating a backing sheet 10 with a liquid mixture containing a melamine alkoxide polymer and a crosslinking catalyst using conventional engraving coating methods. This coating is subsequently subjected to convection heat in order to cure and cross-link the alkyd polymer with melamine to produce a solid thermosetting coating layer on top of the backing sheet.

10. The melamine used in the coating mixture of release layer 5 is a methoxy melamine, preferably hexamethoxymethyl melamine and the preferred crosslinking catalyst is paratoluenesulfonic acid.

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-110 alkyd polymer is formed in a conventional manner by reaction of a polyester and oil. The polymerization reaction can be carried out by cooking the polyester and the oil for a period of time in a suitable tank, preferably using a catalyst, such as sodium hydroxide, under constant agitation, in order to achieve the polymerization of the polyester and oil. The alkyd polymer formed in this way is then cooled and as mentioned above, melamine, preferably hexamethoxymethyl melamine, is added. Melamine is left in the mixture in an unreacted form. This mixture is thus referred to as a liquid mixture of modified alkyd and methoxyamine. Prior to coating the backing sheet 10 with the mixture of modified alkyd and melamine, a catalyst, preferably a paratoluenesulfonic acid catalyst, is added and mixed in the modified alkyd resin until a homogeneous liquid mixture is achieved. Paratoluenesulfonic acid can be obtained under the trademark Cycat 600 from the American Cyanamid Company.

The polyester used in the present alkyl polymer is a hydroxy-functional resin preferably of the type disclosed in U.S. Patent No. ⁹ . 4,654,270, incorporated herein by reference, polyester is preferably a hydroxy-functional resin of the preferred type and composition disclosed in U.S. Patent No. ⁹ .

654 270, at col. 3, lines 15-28. It should therefore be noted that the polyester used here is not a cellulosic ester and is also not a cellulose acetate butyrate or cellulose acetate as disclosed in U.S. Patent No. ⁹ . 3 922 435, of the prior art, at col. 5, lines 51-54. The preferred polyester is, instead, a hydroxy-functional polyester as disclosed in U.S. Patent No. ⁹ . 4 654 270 (col. 3, lines 20-28) which is a copolymer of monoethylenically unsaturated monomers, such as a copolymer, in solution, of 15% 2-hydroxyethyl acrylate, 40% lauryl methacrylate and 45% styrene. The styrene content in this mixture can be replaced with methyl methacrylate or any mixture of styrene and methyl methacrylate as disclosed in this reference. The preferred melamine is hexametoxymethyl melamine disclosed in U.S. Patent No. ⁹ . 4 654 270 in col. 1, line 34. The drying oil used in the thermosetting reaction is typical69 176

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-12 safflower oil but can also be selected from fungi oil, linseed oil, dehydrated castor oil, safflower oil, liquid rosin fatty acid, soybean oil, cottonseed oil, peanut oil, castor oil, olive oil and coconut oil. These are known oils used in the manufacture of alkyd resins and are referenced in this context in Encyclopedia pf Polymer Science and Technology, John Wiley & Sons, Inc. 1964, l / ol. 1, p. 684.

The alkyl polymer mixture formed by reacting the aforementioned preferred esters can be obtained easily from DeSoto, Inc. DePlaines, Illinois. The alkyd polymer mixture can be obtained from DeSoto, Inc. with melamine, preferably hexamethoxymethyl, melamine added in an unreacted form to the mixture as described above. This mixture is described by DeSoto as a mixture of modified alkyd and methoxyminin.

After the paratoluenesulfonic acid catalyst is added to the mixture of modified alkyd and methoxy melamine the mixture will coat the backing sheet 10 and the coating is exposed to convection heat by passing the coating through a convection oven operating at about 180 ° C- 2309C long enough to cure and crosslink the resin with melamine. Note that the melamine additive is the crosslinking agent for the alkyd. The alkyd is said to be modified by the addition of melamine. Melamine does not react until after the release is coated on the paper substrate and cured in a convection oven. In this way the coating becomes cross-linked to produce the thermosetting release layer 5.

In the applicant's preferred system the transfer layer of the varnish coating 20 has the property that, during heat transfer at desirable press temperatures between 140 ° C to 220 ° C, the transferable substrate 15 separates completely from the thermoset release layer 5 without leaving any discernible portion of the varnish coating transfer layer 20 in the release layer 5.

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-130 heat transferable laminate of the invention simultaneously satisfies a large number of additional requirements. The non-waxy thermosetting release layer 5 is easily coated on the backing sheet 10 by conventional engraving methods. The coating with the varnish transfer layer 20, the ink drawing layer 30 and the heat-activable transfer layer 40 is easily accomplished in sequence using engraving methods, but other printing methods such as printing methods press letters, photographic or canvas are also suitable.

Complete separation of the transfer liner 20 from the thermoset release layer 5 is achieved without leaving any discernible portion of either layer on the other when the temperature of the heated press or heated press cylinder is in the range of about 140 ° C to 220 ° C, typically from 150SC to 2209C and preferably from 1402C to 1B0QC. The complete separation of the transfer liner 20 from the thermoset release layer 5 during the heat transfer process without leaving any discernible portion of either layer on the other is considered by the applicant to be a significant success.

An. preferred embodiment of the delivery system according to the invention, which is the combination of the thermosetting release layer 5 in contact with the varnish transfer coating 20, has the important additional property of completely eliminating the problem of the surrounding halo of wax edge of the transferred design image. The wax halo problem has long been associated with wax-based release formulations.

The problem of the halo effect of the wax is eliminated by the delivery system of the present invention since no discernible portion of the thermosetting release layer 5 remains adherent to the transferable substrate 15, when the substrate 15 is transferred to the receiving article. This avoids a problem that has long been associated with wax-based release layers, which tend to form a wax halo effect around the edge of the transferred ink drawing image, given

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-14 that a portion of wax released in these systems is transferred to the article together with the ink drawing.

By transferring the varnish coating layer 20, a strong and transparent protective coating is formed on the ink drawing layer 30 on the receiving article. The transferred protective coating 20 shows a marked improvement in abrasion and scratch resistance compared to what has been achieved with wax-based release layers, for example, of the type described in U.S. patent no. 3,616,015.

By transference, the protective coating, namely coating layer 20 on the drawing layer of transferred paint 30, exhibits marked improvement in abrasion resistance compared to wax-based systems in such a way that if someone tries to scratch with the surface using moderate pressure, no discernible scratch or abrasion marks will be left on the protective layer covering the ink drawing layer 30 on the article. This degree of abrasion resistance is quite difficult to achieve using a wax-based formulation, although improvements have been made to wax-based formulations. A wide range of plastic articles can be used as a receiving surface. However, especially good results are obtained with relatively smooth rigid plastic containers, of any shape or curvature, typically flat, cylindrical, oval, tapered and in various other ways. These plastic articles can typically be of high density polyethylene, polypropylene, polystyrene and poly (vinyl chloride). However, most other common plastics can be used as a receiving article, regardless of whether they are thermoplastic or thermosetting.

Another advantage of the present invention is that it does not require operating heat transfer temperatures that do not differ from conventional press temperatures between about 150 ° C and 220 ° C for transferring the transferable laminate with printed heat design to plastic articles. In addition, in the present invention, the temperature of the press can be as low as 140 ° C. ^ these desirable press temperatures in a gas

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-15ma of about 140 ° C at 220 ° C, were also mentioned in the granted patent application, serial number 181 090 filed on April 15, 1988, patent application that reveals a particular class of thermoplastic release harvesting and not the layer thermoset release 5 as described in the present patent application. The delivery system of the present invention can be used with conventional decorating apparatus, as also, for example, is referred to in U.S. Patent No. 9. 5 616 015. When a wax-based delivery system is used, post-calling is required. The non-wax-based delivery system of the present invention further eliminates the need for post-flaring of the varnish transfer layer 20 after it has been transferred to the article as part of the transfer substrate 15.

Although post-flare can be used to improve the durability of the transfer substrate 15 in the article, it is not necessary. The elimination of the need for the post-flaming step is an additional improvement over the processing required when conventional wax-based release layer or layers are used, for example as described in U.S. Patent No. 9. 5 616 015. Such layers of wax-based release typically require exposure to hot gas jets either as a direct gas flame or as hot air jets for a period of time sufficient to re-melt the wax in order to improve clarity, smoothness and shine of the protective wax-based coating, previously the release layer, after the transferable substrate has been transferred to the receiving article. The elimination of the need for post-flare is a direct result of the improved release system of the invention that does not use any waxes, either in the grindable release layer 5 or in the varnish coating transfer layer 20.

The varnish transfer layer 20 which produced all the desirable properties already mentioned in conjunction with the use of the thermosetting release layer 5 can itself be thermosetting or thermoplastic. A specific formulation pref69 176

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-16ride to a transfer layer of thermoset varnish 20 is given in Table I as formulations A and B. A specific thermoplastic formulation for transfer layer 20 is given in Table I, as formulation C. Formulation C is essentially%

identical to the formulation previously disclosed in the U.S. patent application with serial number 181 090, filed on April 13, 1988.

TABLE I

LAYER OF RELEASE (5):

(e.g., modified alkyd and methoxymethylamine) treated after coating on backing sheet 10.

FORMULATION A

UERNIZ COATING TRANSFER LAYER (20)

Primary resin (eg poly (vinylidene chloride)

SARAN F310)

Secondary Resin (eg, ELUACITE-2042 ethyl methacrylate)

Crosslinking Agents (eg, hexamethylmethoxyamine CYMEL 303) (eg, paratoluenesulfonic acid CYCAT 4040)

Lubricating Agent (eg ALCOLEC S lecithin)

WEIGHT %

100

48.2

48.2

2.4

1.0

TOTAL

100.0

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-17TABELA I (continued)

WEIGHT ;

SOLVENTS

Methyl Ethyl Ketone 59.6

T oluene 59.7

Isopropanol (diluent for cross-linking agent 0.7)

TOTAL 100.0

FORMULATION S

THE

VARNISH COATING TRANSFER LAYER (20):

Primary Resin 40.3 (eg VAR type UCAR vinyl resin solution; poly (uinyl chloride), poly (vinyl acetate) copolymer with hydroxy functionality)

Secondary Resin 40.3 (eg, ELVACITE-2042 ethyl methacrylate)

Cross-linking Agent 2.0 (eg, hexamethylmethoxymethylamine CYMEL 303) (eg, paratoluenesulfonic acid CYCAT 4040)

Lubricating Agent 1.0 (eg, ALCQLEC 5 lecithin)

Tinting sinks 16.2 (eg KETOENELEX-M580 arylsulfonimide)

TOTAL

100.0

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-18TABELA I (cont.)

WEIGHT %

SOLVENTS

Ethyl acetate 74.7

Toluene 24.9

Isopropanol (diluents for the retention agent 0.4)

TOTAL 100.0

FORMULATION C

VARNISH COATING TRANSFER LAYER (20):

Primary Resin (Matrix) 85 (eg VITEL PE-200 Polyester)

Castor Oil 7 (type refined by AA USP)

Polymeric astiFicant PI 8 (eg thermoplastic polyurethane

ESTANE 5715) __

TOTAL 100.0

SOLVENTS

Toluene 21

Methyl ethyl ketone 65

Ethyl acetate 14

TOTAL 100.0 patent application with serial number 181 090 assigned to the same assignee as the present patent application. Formulation C or varnish coating transfer layer 20 was disclosed in patent application under serial number 181 090 for use in conjunction with the polyolefin release layer and not in conjunction with the use of the release layer h alkoxide based 5, as described in the present patent application.

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-19The formulation A shown in table I shows a mixture of resin coating in a solvent system that will coat the release layer 5, using the conventional gravure printing method. The coating is then passed through a convection oven operating at about 12 09 C for sufficient time to evaporate the solvent and cause the coating to cure and crosslink to form a transfer layer of thermoset varnish 20. The preferred formulation A shown in table I, for the varnish transfer layer 20, is composed of a primary resin, preferably a commercially available poly (vinylidene chloride) resin under the trademark SARAN F310 from Dow Chemical Company and a secondary resin preferably ethyl methacrylate available under the trademark ELVACITE -2042 from DuPont Corp. The crosslinking agents, preferably hexamethylmethoxymethylamine and paratoluenesulfonic acid are added to the formulation to compel at least the primary resin to crosslink and cure when the coating is passed through the convection ovens. The hexamethylmethoxymethyl crosslinking agent is commercially available under the trademark CYMEL 303 from the American Cyanamide Company and the crosslinking agent paratoluenesulfonic acid is available under the trademark CYCAT 4040 from the American Cyanamide Company.

We have determined that the addition of a lubricating agent, preferably lecithin, promotes a smoother surface of the transfer layer 20 when it is transferred from the release layer 5 to the receiving article. The solvent shown in Formulation A are conventional solvents for the resin and crosslinking agents. These solvents make it possible to obtain a homogeneous mixture for Formulation A so that it can be easily coated onto the release layer 5 using conventional engraving coating techniques. The varnish transfer layer 20 can also be used without the lubricating agent.

The applicant obtained a clear improvement in the degree of smoothness of the surface of the layer 20, when the lubricating agent, preferably lecithin, was used in the formulation. The au69 smoothness 176

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-20ment of the surface of the transfer layer 20, provides a discernible increase in brightness to the transferred ink drawing layer when the transferable substrate 15 is transferred to the receiving article. The increased brightness of the transferred varnish layer 20 gives the ink drawing 30 a more pleasant appearance than that which would have been obtained if the lubricating agent had not been used in the formulation. It is theorized that the increase in the smoothness of the transfer layer 20 surface is the result of an increase in the smoothness of the interfacial surface i between the thermoset release layer 5 and the varnish transfer layer 20, when heat is applied to the foil. support 10.

It is theorized that when heat is applied to the backing sheet 10, the lubricating agent becomes activated and migrates to the interfacial surface i at the moment when the transferable substrate 15 is transferred from the release layer 5 to the receiving article. Since the transfer layer 20 is transferred together with the ink drawing layer 30 to the receiving article, it is believed that the increase in the surface smoothness of the transfer layer 20 is responsible for the overall increase in the brightness of the design the ink transferred 30.

Another preferred thermosetting formulation for transfer layer 20 is shown as Formulation B in Table I. This preferred formulation is similar to Formulation A except that a different primary resin is used and a pi as tif ic an is also added to the formulation. te. The primary resin shown in Formulation B is a copolymer of poly (vinyl chloride) and poly (vinyl acetate) with hydroxy functionality to allow crosslinking during curing. This resin is commercially available under the trademark UCAR VAGH vinyl resin solution from Uni on Carbide Corp. The preferred plasticizer is an arylsulfonimide, such as that available under the trademark KETJENFLEX-F38Q from Akzo Chemie, a Dutch company.

The mixtures shown in formulation A and formulation 6 are each prepared by simply mixing the components listed under environmental conditions using conventional electric mixers for about an hour typically or until

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-21get homogeneity. Typically the solvents are first added in an empty mixer bowl and then the components combined and mixed for a short time by mixing the components in the same order as they appear in the table.

The crosslinking agents are preferably added at the end and first diluted with isopropanol before addition to the mixture. In the production of the coating mixture, the solvents shown in Formulation A and Formulation B are added in a proportion of about 3 parts of total solvent for about 1 part solids, where solids are defined as all components different from the listed solvents.

tion 5

Therefore, preceding the coating of the release layer, with the homogeneous mixture, the mixture can be slightly diluted again, typically to obtain a mixture of about 4 to 5 parts of solvent for 1 part of solids, so that the mixture can be easily coated onto the release layer 5 using conventional etching techniques. After Formulation A or Formulation B for the trans layer. The transfer 20 is coated on the thermosetting release layer 5, the coating is subjected to convection heat, passing it through conventional convection ovens, typically operating at around 12030 to evaporate the solvents and simultaneously cause the resin to cure and crosslink in the formulation. It is believed that the primary resin is the resin that becomes crosslinked in the curing operation. The secondary resin is believed to contribute to the overall hardness and durability properties of the transfer layer 20. The cured transfer layer 20 is not believed to be involved in the crosslinking reaction, e.g. less, to the same degree as the primary resin. Although the cured transfer layer 20 using formulation A and B is cross-linked and has a highly thermosetting character, it also exhibits some thermoplastic characteristics as it softens slightly and becomes somewhat malleable when heated.

When transferring layer 20 together with the ink drawing layer 30, formulation A and formulation B each confer all the desirable characteristics mentioned above to the

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-22CJtnsda of the transferred ink drawing. Specifically Formulation A and B each provide a high gloss transfer layer 20, with great surface smoothness, great optical clarity, and a markedly better scratch and abrasion resistance when compared to wax-based systems. These properties are all obtained without transferring any discernible portion of the release layer 5 together with the transfer layer 20. This is in sharp contrast to the wax-based release systems that fragment and transfer together with the drawing image for the receiving item.

Another preferred formulation is shown as formulation C for the varnish coating transfer layer 20. Formulation 0 is completely thermoplastic in character. Formulation C is composed of a primary resin, an oil and preferably a polymeric plasticizer additive. The primary resin is preferably a polyester resin, which is a linear saturated aromatic polyester, preferably poly (ethylene terephthalate) such as that available under the trademark VITEL PE-200. Es. The particular polyester resin is manufactured and available from Goodyear Chemical Company of Akron, Ohio. The additive oil is a non-drying oil preferably castor oil preferably AA USP of the refined type which is available on the market from CAS CHEM COMPANY, Dayonne, NY. The VITEL resin and castor oil are mixed in a suitable solvent system as shown in Formulation C. Castor oil is present in relatively small amounts. The percentage of castor oil by weight of the dry transfer coating 20 (on a solvent free basis) should be about 1.0 percent to about 15 percent by weight. It has been determined that the addition of castor oil to the thermoplastic formulation C promotes the release effect between the thermosetting release layer 5 and the predominantly polyester varnish coating layer 20. It is also believed that the inclusion of non-drying oil, such as castor oil, increases the degree of smoothness and thus brightness of the transferred layer 20.

It is theorized that when the heat of a hot press is applied to the backing sheet 10 while the adhesive layer 40 of it

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-23minute 7 contacts the receiving article, the non-drying oil becomes active and migrates to the interfacial surface i between the thermosetting release layer 5 and the varnish transfer layer 20. This phenomenon is believed to promote transfer complete transfer of the varnish transfer layer 20 from the thermoset release layer 5. The addition of a polymeric plasticizer such as thermoplastic polyurethane, for example ESTA | 1E 5715 to Formulation C is seen as an optional addition.

However, it has been found that the addition of such a plasticizer causes an increase in the flexibility of the dry varnish coating release layer 20 to make layer 20 transferred in the article somewhat less subject to cracking if the article is heavily folded or distorted. As previously described, Formulation C is disclosed in patent application serial number 181 090 filed on April 13, 1988 by the same assignee as the present application. If formulation C is used for transfer layer 20, it is prepared by simply mixing resin oil and plasticizer in a vat at room temperature with the solvent system shown in table I for this formulation. Solvents are typically added in a proportion of about 3 to 4 parts of solvent to 1 part of the remaining constituents and mixing is carried out until a homogeneous mixture is achieved. The mixture can then be coated directly onto the thermoset release layer 5 using conventional engraving techniques. After coating the transfer layer 20 is pas. by convection ovens typically operating between about 80 ° C and 120 ° C, where it is exposed to forced hot air to remove solvents and form a dry, strong coating layer.

The ink drawing layer 30 and the heat-activated adhesive layer 40 can be composed of conventional formulations known in the art for use in heat transferable laminates of this type. For example, the ink drawing layer 30 can be composed of any conventional ink of any color. The paint can typically include a resinous bonding base compatible with the paint pigment used. The paint binder can be selected from a wide variety of resin bases69 176

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-24 conventional substances such as poii (vinyl chloride), acrylics, polyamides and nitrocellulose. The ink is also applied by a coating, engraving or similar method and then passed through convection ovens for one or two seconds in order to remove solvents and leave a dry ink drawing layer 30 on the transfer layer of dry varnish coating 20.

It is advantageous in this technology to cover the ink drawing layer 30 with a heat-activated adhesive coating 40 which facilitates the transfer of the transferable substrate 15 to the article to be decorated. The adhesive layer 40 becomes activable by exposure to the heat of a hot press, in contact with the support sheet 10 during the transfer process. At the transfer temperature, the components in the adhesive layer 40 become sticky so that there is sufficient adhesion between the article to be decorated and the transferable substrate 15 in contact with it. Adhesive layer 40 is also applied to the solvent base by engraving or other conventional coating methods and the solvent is removed by exposing the coated layer to drying by convection for one or two seconds or long enough to evaporate the solvent , leaving the adhesive coating layer dry on top of the ink drawing layer 30. The bed of adhesive 40 may acceptably be composed of a thermoplastic polyamide adhesive, preferably a low temperature heat-activated polyarticle adhesive.

A preferred thermoplastic polyamide resin for adhesive layer 40 is the reaction product of a diamine with a dimerized fatty acid such as that available under the registered trademark UE RSA MI D series 900, or preferably adhesive UE RS The low temperature heat-activated MI D from Henkel Corp. from Hinnea Polis, Minnesota. We have found it advantageous to combine this polyamide constituent with a nitrocellulose base in adhesive layer 40. This type of heat-activated adhesive for this application is known and is documented in the prior art.

In the process of applying heat transferable laminate 7 to an article such as a plastic bottle or container. At least 60 of these items can be decorated per minute.

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Using the formulations for release layer 5 and varnish coating transfer layer 20 as shown in Table I, it has been determined that with items typically plastic bottles, they can be decorated at least between about / ^ 60 to 120_7 articles per minute using the formulations for release layer 5 and varnish coating transfer layer 20 shown in table I. In this process, as described above, when the heat released by a hot metal press or a press cylinder hot rubber is applied to the exposed side of the backing sheet 10 while the adhesive layer 40 of the laminate 7 comes into contact with the decorated bottle or article, the transferable substrate 15 separates completely from the carrier web 2 and transfers to the article. At a decorating speed of about 60 to 120 bottles per minute, the porta dora web is in direct and intimate contact with the hot press for at least about 0.25 seconds.

Successful tests have also been carried out using the formulations shown in table I at decorating speeds of at least about 60 to 120 bottles per minute with average press surface temperatures of around 140 ° C and direct contact time between press and laminate of at least 0.25 seconds crown. In this preferred process, laminate 7 is first typically preheated to temperatures between about 80 ° C and 110 ° C before coming into contact with the aforementioned hot metal presses with the hot rubber press cylinder. The preheating step is preferably achieved by passing the laminate 7 over a heated metal surface so that the metal surface contacts the exposed side of the backing sheet 10 during the required buffer to reach the desired pre-set temperature. laminate heating.

Although the invention has been described within the context of particular embodiments for the transferable laminate, the envy is not intended to be limited to the preferred formulations described herein. Although the varnish transfer coating layer, for example, has been described with reference to preferred formulations with specific resins together with a small

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-26 amount of lubricating agent, or non-drying oil, the formulation for the varnish coating layer is not intended to be limited to these particular resin and oil species, respectively. It should also be borne in mind that traces or minimal non-functional amounts of waxes can be added to the layers referred to here as non-waxy layers without falling outside the scope of the applicant's invention. Therefore, the term non-waxy layer or equivalent, as used in the previous description, is intended to encompass this possibility.

The invention, therefore, is not intended to be limited to the description in the specification but rather to be defined by the claims and their equivalents.

Claims (15)

1 - Process of production of a heat transferable laminate, comprising a transferable substrate and a carrier sheet, for transfer from the carrier sheet to an article. go, by applying heat to the carrier sheet when said article contacts the transferable substrate, characterized in that a support sheet is coated with a non-pink release layer, comprising a thermosetting alkyd resin, in order to form said sheet carrier, non-waxy release layer that will be in contact with said transferable substrate, which is obtained by coating, with an ink drawing layer, a transfer coating, which will be in contact with said release layer non-waxy, affixing said transferable substrate to the carrier sheet, after which said heat transferable laminate has the property that, when a heat source is applied to the carrier, said transferable substrate in contact with the article, the transferable substrate separates completely from said non-waxy release layer and transfers to said article o, said heat transferable laminate still having the additional property that no discernible portion of said non-waxy release layer is transferred to the article with said transferable substrate. Process according to claim 1, characterized in that the thermosetting alkyd resin comprises the reaction product of crosslinking an alkyd polymer with a molasses; and in that said alkyd polymer is formed from the reaction product of an ester with hydroxy function and an oil, in which you are. having is a non-cellulosic ester. Process according to claim 2, characterized in that the hydroxy-functional ester comprises the copolymer of monoethylenically unsaturated monomers. Process according to claim 3, characterized. because the ester with hydroxy function comprises the copolymer of 2-hydroxyethyl acrylate, lauryl methacrylate and styrene. 69 176 1460 20. A process according to claim 3, characterized by the color ester. the hydroxy functionality comprises a copolymer of 2-hydroxyethyl acrylate, lauryl methacrylate and methyl methacrylate. Process according to claim 2, characterized in that the oil is selected from the group consisting of tung oil, linseed oil, castor oil, safflower oil, cottonseed oil, peanut oil and oil Of coconut. Process according to claim 2, characterized in that the melamine is hexamethoxymethyl melamine. Θ - Process for the production of a heat transferable laminate, comprising a transferable substrate, and a carrier sheet, for transferring the carrier sheet to an article, by applying heat to the carrier sheet when said contact with the transferable substrate , characterized in that a support sheet is coated with a non-waxy release layer, comprising a thermosetting alkyd resin formed by the crosslinking reaction product of a non-cellulosic alkyd polymer with melamine, in order to form the carrier sheet, layer of non-waxy release that will be in contact with said transferable substrate, which is obtained by coating with a bed of the ink drawing, a transfer coating, transfer coating that will be in contact with said release layer not waxy, affixing said transferable substrate to the carrier sheet, after which said heat transferable laminate has the property that, when a heat source is applied to the carrier, said transferable substrate in contact with the article, the transferable substrate separates completely from said non-waxy release layer and transfers to the said article, said heat transferable laminate still having the additional property that no discernible portion of said non-waxy release layer is transferred to the article with said transferable substrate, the transfer coating of said transferable substrate comprising a resin selected from of a group. powder consisting of vinyl resins and polyester resins. 69 176 1460 -299 - Process according to claim 3, characterized. provided that the vinyl resins of said transfer coating comprise poii (vinylidene chloride). Process according to claim B, characterized in that the vinyl resin of said transfer coating comprises the copolymer of poly (vinyl chloride) and poly (vinyl acetate), having a hydroxy functionality that allows crosslinking. Process according to claim B, characterized in that the polyester resin of said transfer coating comprises a poly (ethylene terephthalate). Process according to claim 9, characterized in that the transfer coating further comprises lecithin. Process according to claim 10, characterized in that the transfer liner further comprises lichine. Process according to claim 3, characterized. that said aikidic polymer is formed by the reaction product of an hydroxy-functional ester and an oil, wherein the ester is a non-cellulosic ester. 15. Laminate production process according to claim 14, characterized in that the hydroxy-functional ester comprises the copolymer of monoethylenically unsaturated monomers. A process according to claim 15, characterized in that. the hydroxy-functional ester comprises the 2-hydroxyethyl acrylate copolymer, lauryl methacrylate and styrene. Process according to claim 15, characterized in that the hydroxy-functional ester comprises the copolymer of 2-hydroxyethyl acrylate, lauryl methacrylate and methyl methacrylate. A method according to claim 14, characterized. used because the oil is selected from the group consisting of 69 176 1460 -30 by tung oil, linseed oil, castor oil, charcoal oil, liquid rosin, soy oil, cottonseed oil, peanut oil and coconut oil.