JPS5942636B2 - Improved thermal transfer material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal transfer body used for applying decorative and/or informational label stamps or marks (hereinafter simply referred to as labels) to articles, in particular textile articles.

The applicant has British Patent Nos. 928347 and 120171.
No. 3, No. 1287452 and No. 1386392 disclose various thermal transfer bodies.

Such transfer bodies consist, briefly, of a temporary support and a label thereon, which is an insoluble and resistant material that is inert when exposed to heat and pressure in contact with the article to be marked. It consists of a resin system that cures to an abradable form to provide a substantially permanent mark on the surface of the article. Marks formed from resin systems such as those described in the above-mentioned patents are subject to certain limitations that limit their usefulness.
In particular, such resin systems become relatively non-stretchable after crosslinking;
It is necessary to apply high pressure to ensure good adhesion to the fabric being marked. Such resins also tend to crack when creating unsupported bridges between the threads of open woven fabrics. In particular, thick fabrics, such as wool, which absorb significant amounts of water during laundering, can cause the transfer material to crack during laundering. Due to such limitations, the aforementioned resin systems are
For use in transfers to be applied to tightly woven fabrics such as fine cotton fabrics, thick twill cotton fabrics, acetate rayon and nylon linings, cotton, cotton/polyester and nylon (including warp knitted nylon) shirt fabrics. Limited.

A similar limitation is evident when one considers that since the applied pressure is of the order of 2-4 kg/d, labels can only be applied without damage to fabrics that are not destroyed by this pressure. German Patent Publication No. 2549210 of the present applicant describes a thermoplastic polyurethane elastomer whose label is a reaction product of the following reactants (a) to (c) as a thermal transfer material that eliminates or alleviates the above-mentioned drawbacks. There is described a layer consisting of a polyurethane resin layer containing: (in the formula, R
is an alkylene group having 2 to 8 carbon atoms, and R' is an alkylene group having 4 to 10 carbon atoms) or the formula: (wherein R
1 mole of a substantially linear hydroxyl-terminated polyester having repeating units of `` is an alkylene group of 4 to 8 carbon atoms, having an average molecular weight of 600 to 1200 and an acid number of less than 10; ) 1.1 to 3.1 mol of a diphenyl diisocyanate compound having an isocyanate group on each benzene nucleus; and (c) 0.1 to 2.1 mol of at least one free glycol having 2 to 10 carbon atoms; The total average hydroxyl value of the polyester and free glycol is 450 to 600, and the total molar amount of the polyester and glycol is substantially equal to the molar amount of the diisocyanate compound.

This polyurethane resin system is further blended with an acid catalyst or an acid-generating catalyst and a compound having two or more N-alkoxymethyl groups as a crosslinking agent, and thus the layer of the polyurethane resin system is brought into contact with the article to be marked and exposed to heat. Upon application of pressure, the polyurethane crosslinks into an inert, insoluble and abrasion resistant form to provide a substantially permanent mark on the article. Such thermal transfer bodies can be used to mark articles such as textiles, and in particular to apply stretch labels to stretch fabrics such as knitwear or jersey. However, labels thus applied have the disadvantage that they can only be washed under relatively mild conditions; more intensive washing often leads to deterioration and cracking of the labels. Needless to say, this is particularly disadvantageous if the applied label does not include washing instructions. It is an object of the present invention to provide a thermal transfer body which avoids or alleviates the above-mentioned drawbacks and disadvantages.

Therefore, the present invention provides formula (4): (wherein, R is an alkylene group having 2 to 8 carbon atoms, and R
is an alkylene group having 4 to 10 carbon atoms) or the formula: (
a substantially linear hydroxyl-terminated polyester having repeating units of the formula (R'' is an alkylene group of 4 to 8 carbon atoms), having an average molecular weight of 1200 to 3000 and an acid number less than 10. mol; (8) 1.1 to 3.1 mol of a diphenyl diisocyanate compound having an isocyanate group on each benzene nucleus; and C) 2 to 3 carbon atoms;
10 at least one free glycol 0.1-2.1
mol; and the total average hydroxyl value of the polyester and the free glycol is 450 to 1200.
A polyurethane resin layer formed from a solution obtained by dissolving a thermoplastic polyurethane elastomer in a solvent, the total molar amount of which is substantially equal to the molar amount of the diisocyanate compound. A label having the following characteristics is provided on a temporary support, and the polyurethane resin system is compounded with an acid catalyst or an acid-forming catalyst and a compound having two or more N-alkoxymethyl groups as a crosslinking agent. When the polyurethane resin-based layer is brought into contact with the article to be marked and heat and pressure are applied, the polyurethane is cross-linked to an inert, insoluble and abrasion resistant form to form a substantially durable material on the article. Provided is a thermal transfer material that provides a mark.

Thus, the polyester urethane used in the present invention is similar to that described in DE 25 49 210 mentioned above, but contains a higher molecular weight polyester component (4).

Although these two types of polyurethanes have very similar chemical structures, the polyurethanes used in the present invention have various unexpected and surprising properties that result in significantly improved thermal transfer materials. In particular, a thermal transfer label according to the invention can be applied to an article by the action of heat and pressure to provide a mark on the article that is resistant to hot washing and retains its appearance even after a number of such washings.

The decals of the invention can be used to apply stretch labels to stretch fabrics, and such labels are thinner than in the case of labels formed from polyester urethane as described in the above-mentioned German Patent Application. Shows good elastic resilience.

This obviously reduces the amount of polyurethane required to form the label, thus lowering manufacturing costs and time. Furthermore, the polyester urethane resin system used in the present invention can be crosslinked more rapidly than those described in the above-mentioned publications, so the time for the transfer operation is reduced and in addition there is less flow of resin during this operation. This results in a brighter and more opaque color.

Another advantage provided by the present invention is that the preparation of the transfer is facilitated because the polyester urethane solution or ink dries to a non-tacky film during production. Although the polyester urethanes used in the present invention are less soluble in conventional solvents than those described in the above-mentioned publications, they can be dissolved in cyclohexanone with high speed mixing, and from such solutions the thermal transfer material is free from irritants. If you are careful about cyclohexanone vapor, you can make a dragon by the usual method.

The polyurethane resin system used in the present invention has a repeating unit of the formula ◆Fuoshishishi-K-shiichiυ-K-υ'T,) having a carbon number of 4 to 10 and a hydroxyl group on the terminal carbon atom. saturated glycols and the formula HOOC-R-C
It can be produced by reacting OOH (where R is an alkylene group having 2 to 8 carbon atoms) with a dicarboxylic acid or anhydride thereof.

The polyesters used in the production of polyurethanes preferably have from 4 to 8 methylene groups per ester group. Examples of polyesters that may be used are: A (1) prepared from adipic acid and 1,4-butanediol (R and R' having 4 carbon atoms) with a molecular weight of approximately 1210,2000,2
500 or 3000 polyester; A(Ii) co...
Citric acid (R has 2 carbon atoms) and 1,8-octanediol (R
A polyester with a molecular weight of about 2,000 manufactured from adipic acid and 1,8-octanediol; ,8-
A polyester with a molecular weight of about 2000 made from octanediol; and a polyester with a molecular weight of about 200 made from A(v) caprolactone.
0 polyester.

As used herein, the term 1 diphenyl diisocyanate compound refers to 1 diphenyl diisocyanate compound directly or
has two phenyl groups bonded to each other through two or more atoms, and each phenyl group is -NCO
It includes compounds having substituents.

Diphenyl methane diisocyanate is particularly suitable for producing polyurethane resins, and the diphenyl diisocyanate compound is preferably diphenyl-P,p'-diisocyanate.

Examples of suitable diisocyanates used in the production of polyurethanes are shown below. B(1) 4,4'-diphenylmethane diisocyanate.

B(Ii) 3,3'-dichloro-4,4'-diphenylmethane diisocyanate.

B(Iii) 3,3'-dimethyl-4,4'-biphenyl diisocyanate.

B(1V) 4,4'-diphenyl ether diisocyanate.

BCV) 3,3'-dimethyl-4,4'-diphenyl ether diisocyanate.

BOll) 4,4'-diphenyldimethylmethane diisocyanate.

BtlD4,4'-dibenzyl diisocyanate.

The dilutable glycol has the formula HO(CH2)NOH (n is 2 to 1
01, preferably 2 to 8) are preferred. Examples of suitable glycols are shown below. A suitable polyester polyurethane used in the present invention is 1 mpra
It is commercially available from Baier Company under the trade name "ni1".

The thermoplastic polyurethane resin system is formulated with a crosslinking agent and an acid catalyst or a acid forming catalyst so that under transfer conditions the polyurethane is converted to an inert, insoluble and abrasion resistant form.

The crosslinking agent used to cure polyurethane resins means that the resin will not cure during long storage periods at room temperature or at the temperature at which the transfer body was manufactured, but will cure rapidly at transfer temperatures to provide a substantially durable mark. selected to give

Suitable crosslinking agents are compounds containing two or more N-alkoxymethyl groups, preferably N-methoxymethyl groups, examples of which are given below. N,N'-bis(methoxymethyl)urea, trimethoxymethylmelamine, hexamethoxymethylmelaminetetramethoxymethylurea, urea-formaldehyde initial condensate containing a methoxymethyl group, melamine-formaldehyde initial condensate containing a methoxymethyl group, Urea-formaldehyde initial condensate containing hexaethoxymethylmelamine ethoxymethyl group, melamine-formaldehyde initial condensate containing ethoxymethyl group, N,N'-bis(methoxymethyl)metaphenylenediamine alkylated melamine or urea resin initial condensation Butylated melamine or urea resin initial condensate,
The crosslinking agent may be used in amounts up to 30% by weight, preferably from 5 to 20% by weight, based on the weight of the dry resin.

As the catalyst for the crosslinking agent, it is preferable to use a nonvolatile acid having a PKa value of 2 to 5, preferably 2.5 to 3.5.

Stronger acids tend to cause a significant degree of crosslinking at room temperature, resulting in thermal transfers with a lower shelf life, while weaker acids do not act quickly enough under marking conditions. Examples of suitable acid catalysts are tartaric acid, phosphoric acid, citric acid, orthophthalic acid, isophthalic acid, itaconic acid and salicylic acid.

Alternatively, compounds that generate acids under the marking conditions may be used, such as anhydrides and asmonium salts of acids. The amount of acid catalyst or acid generating catalyst required depends on the PKa of the acid, its basicity and equivalent weight. Usually amounts of 0.5 to 10% by weight, based on the weight of the resin, are sufficient, and best results are obtained with amounts of 1 to 4% by weight. Thermal transfer materials containing a polyurethane resin system with a cross-linking agent and an acid catalyst as described above have an excellent shelf life, but the polyurethane is quickly cross-linked under the transfer conditions to an inert, insoluble, and abrasion-resistant form that can be applied to the article. This gives the article a substantially durable mark that withstands the harsh conditions of rinsing, pressing and dry cleaning that the article can undergo.

The mark thus formed is stretchable despite its crosslinked structure and can also be used on fabrics such as knitwear and jersey. Transfer labels according to the invention can also be applied to rough or bulky fabrics at pressures as low as 0.1 kg/CTd, meaning that such fabrics can be labeled without unsightly compression marks. do.

Thus, according to the invention, jersey fabrics such as cotton, wool, nylon, etc., including sports shirts, swimwear, etc.; bulky polyester nylon and acrylic fabrics such as those used in women's dresses; Can be successfully labeled.

Certain plastics and plastic-coated articles can also be labeled. The low applied pressure also means that the tendency of the label to penetrate through a single thickness of fabric and come out the other side is significantly reduced.

Fabric deformation in the label area is also reduced. Thermal transfer bodies included within the scope of the present invention have various embodiments,
Their structures are detailed below.

In all cases, the transfer body has a label on a temporary support, which temporary support is removed after the marking operation.

The support may consist of a suitable release agent, such as cellulose triacetate, in the form of an unsupported film or laminated or coated on a suitable paper. Alternatively, the support may consist of polyethylene terephthalate in film form, commercially available under the trademarks "MELINEX" or 1MYLAR, in unsupported form or laminated to a suitable paper. A variety of commercially available release agent coated papers may be used. In one embodiment of the transfer, the label is applied to the support by applying a polyurethane resin based solution containing an acid catalyst and a curing agent to the support and then drying to form a continuous resin layer.

On this continuous layer, preferably containing the same resin system as that used in the continuous layer and typically in an organic solvent such as a ketone (e.g. cyclohexanone), a mixture of ketones, an alcohol or an aromatic hydrocarbon. The desired pattern is printed with an ink prepared as a 25% solution. This ink is pigmented by a conventional method, and printing is performed by a conventional method such as screen printing. When this transfer is applied to an article, the continuous layer becomes the top layer of the applied label, thus forming a protective layer for the printed text or pattern. Optionally, a second continuous layer of polyurethane resin of the same or different type as the first Q continuous layer may be applied on top of the transfer body to sandwich the printed text and to form a backing layer when the label is applied to the article. can.

If desired, this backing layer can be of a contrasting color to the printed text. In the case of this type of three-layer structure,
Conventional printing inks can be used since they are protected by two resin layers.

In another type of thermal transfer body, the required markings of a printing ink based on a polyurethane resin system can be applied directly to the support and then covered with a continuous layer of polyurethane resin.

The use of a pigmented coloring solution in this continuous layer forms the colored back layer of the applied label. In yet another type of transfer body, one or more individual printed characters or pattern marks based on a polyurethane resin system are applied to a temporary support body, and the assembly itself is used as a thermal transfer body in which the printed characters constitute a label. Can be used.

However, the required color purity (IntensityOf
cOlOr), a large amount of pigment had to be included in the ink, which was found to have an adverse effect on label integrity.

This difficulty can be overcome by providing each printed character with a substantially bordering or slightly overlapping polyurethane resin based layer (preferably a transparent layer) to act as a bonding layer. If desired, each printed character can be interposed between such two layers to provide a bonding layer and a protective layer for the label. Thermal transfer bodies according to the invention are generally used for applying labels to flexible articles, in particular to textile materials. To label such articles, the thermal transfer member is brought into contact with the article with the support surface facing up, and the temperature is 150-250°C, 0.
．． Pressure is applied for 2 to 20 seconds at a pressure of 1 to 4k9/Crli. Thus, the polyurethane resin system in contact with the article cures and becomes bonded to the article. The pressure is then released and the temporary support peeled off, leaving the label firmly bonded to the surface of the article. Next, the present invention will be further explained by examples.

The polyurethane used for manufacturing the thermal transfer body is designated by the above code A.
-C made from various polyesters, diisocyanates and glycols as shown in Table 1.

These polyurethanes can be produced by the same method as Production Examples 1 to 3 described in the above-mentioned West German Patent Publication.
Each of polyurethanes 1-12 was dissolved in cyclohexanone to obtain 12 stock solutions containing 20 weight polyurethanes.

A printing lacquer was then prepared by adding 2% hexamethoxymethyl melamine and 0.2 (fl) citric acid to the stock solution. 10% titanium dioxide, 6% cadmium red or carbon black 3 (:f/) was added to this printing lacquer to obtain white, red or black ink, respectively. Using the ink and printing lacquer described above, the transfer material is prepared by screen printing onto a laminate of paper and Melinex (a trade name for polyester film) which acts as a release coating, which acts as a temporary support. Manufactured.

Letters are printed in mirror image form on the temporary support using the ink described above, and the letters are coated with a layer of printing lacquer prepared from the same or different type of polyurethane as the ink so that the total thickness is about 50 microns. A single colored heat transferable image was created by overlaying the images.

A multicolor transfer body was also created by layering letters sequentially printed using inks of different colors and finally with a layer of printed lacquer to give a total thickness of about 50 microns.

The thus-produced transfer body was pressed against various fibered and knitted fabrics, including stretchable fabrics, using a 200° C. hot press at a pressure of 1 kg/kg for 5 seconds, and then the temporary support was removed.

The marks thus applied were tested by stretching, washing at various temperatures and ironing.

Claims (1)

[Claims] 1 Formula (A): ▲There are numerical formulas, chemical formulas, tables, etc.▼ (In the formula, R is an alkylene group having 2 to 8 carbon atoms, and R
' is an alkylene group having 4 to 10 carbon atoms) or the formula:
▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R″ is an alkylene group with 4 to 8 carbon atoms)
1 mole of a substantially linear hydroxyl-terminated polyester having repeating units of from 1200 to 3000 and an acid number less than 10; 3.1 mol; and (C) 2 to 1 carbon atoms
0.1 to 2.1 mol of at least one free glycol; the total average hydroxyl value of the polyester and the free glycol is 450 to 1200, and the total molar amount of both is 0.1 to 2.1 mol; Provided on the temporary support is a label having a layer based on a polyurethane resin formed from a solution obtained by dissolving a thermoplastic polyurethane elastomer in a solvent that is substantially equal to the molar amount of the diisocyanate compound. Moreover, the polyurethane resin layer can be marked by adding a compound having two or more N-alkoxymethyl groups to the polyurethane resin system as an acid catalyst, an acid forming catalyst, or a crosslinking agent. A thermal transfer material wherein the polyurethane is cross-linked to an inert, insoluble and abrasion resistant form when brought into contact with the article to be applied and subjected to heat and pressure to provide a substantially permanent mark on the article. 2. The thermal transfer material according to claim 1, wherein the polyester has 4 to 8 methylene groups per ester group. 3 The free glycol has the formula: HO(CH_2)_nOH(
The thermal transfer material according to claim 1 or 2, wherein n is an integer of 2 to 8. 4 Claim 1 in which the diphenyl diisocyanate compound is diphenyl-p,p' diisocyanate
The thermal transfer body according to any one of items 1 to 3. 5. The thermal transfer material according to any one of claims 1 to 4, wherein the diphenyl diisocyanate is diphenylmethane diisocyanate. 6. The thermal transfer material according to any one of claims 1 to 5, wherein the crosslinking agent is present in an amount of 30% by weight or less based on the weight of the dry resin. 7. The thermal transfer material according to claim 6, wherein the crosslinking agent is used in an amount of 5 to 20% by weight. 8. The thermal transfer material according to any one of claims 1 to 7, wherein the N-alkoxymethyl group is an N-methoxymethyl group. 9. The thermal transfer material according to claim 8, wherein the crosslinking agent is a methoxymethyl melamine compound. 10. The thermal transfer material according to claim 9, wherein the crosslinking agent is hexamethoxymethyl melamine. 11. The thermal transfer material according to any one of claims 1 to 10, wherein the catalyst is a nonvolatile acid having a pKa of 2 to 5 or a compound that produces such an acid under marking conditions. 12. The thermal transfer material according to claim 11, wherein the nonvolatile acid has a pKa of 2.5 to 3.5. 13. The acid is present in an amount of 0.5 to 10% by weight based on the dry weight of the resin.
Thermal transfer material. 14. The thermal transfer member according to claim 13, wherein the acid is used in an amount of 1 to 4% by weight based on the dry weight of the resin. 15. The thermal transfer material according to any one of claims 11 to 14, wherein the acid is citric acid or tartaric acid. 16. The thermal transfer material according to any one of claims 11 to 14, wherein the acid generating catalyst is an ammonium salt or anhydride of an acid. 17. The thermal transfer member according to any one of claims 1 to 16, wherein the label comprises a continuous layer of a polyurethane resin system and a mark on the continuous layer based on the same or different polyurethane resin system. 18. The thermal transfer material according to any one of claims 1 to 16, wherein the label comprises two consecutive layers of the same or different polyurethane resins and marks inserted between the layers. 19. The thermal transfer body according to claim 18, wherein the mark is based on a polyurethane resin system. 20. Claims 1 to 19, wherein the label consists of a mark, a back layer and an uncolored continuous layer, all of which are based on the same or different polyurethane resin systems.
The thermal transfer material according to any of the items. 21 Claims in which the label consists of a mark based on a polyurethane resin system and a layer of the same or different polyurethane resin system bordering or slightly overlapping this mark to form a bonding layer when the label is applied to the article Range 1
The thermal transfer body according to any one of Items 1 to 16. 22. The thermal transfer material according to claim 21, wherein the mark is inserted between two layers of the same or different polyurethane resins, and these layers are in contact with or slightly overlap the mark.