MXPA97003972A - Printing process of a single step and double substrate and the substrates asi impre - Google Patents

Abstract

The present invention relates to a single-pass and dual substrate printing process, comprising: providing a first constantly moving substrate, moving the first substrate towards the printing station, printing a pattern on the first substrate at the station of ink printing, introduce a second substrate that moves constantly between the first substrate and the ink printing station, print a pattern on the second substrate and collect the ink that passes through the second substrate in the first substratum

Description

PRINTING PROCESS OF A SINGLE STEP AND DOUBLE SUBSTRATE AND THE SUBSTRATES SO PRINTED The present invention pertains to a process for printing substrates and substrates printed therewith.

Ink printing is well known in fabrics, such as woven and non-woven fabrics, with different patterns and colors. Then these woven fabrics are incorporated into different products, such as personal care products. Examples of personal care products include diapers, diapers, trainers, incontinence products and the like. Printed fabrics are used, mainly to improve the appearance of the products.

A current problem in ink printing processes is that the ink or inks can be run, i.e., penetrate through the fabric, and particularly, into a low basic weight fabric. Low weight basic fabrics are generally thin, and inherently include a small number of voids, or a smaller number of large voids, through which the ink can penetrate. The problem with the penetration of the ink is that the ink accumulates, for example, a printing cylinder of a printing apparatus. This accumulation in the print cylinder results in poor print quality on the fabric, ink transfer on the back of the fabric and poor efficiency, due to the time it takes for the machine to stop to remove the conglomerate from ink.

This problem is even more significant in high-speed printing environments, where the ink conglomerate accelerates and increases the number of times the machine needs to be stopped, to remove the accumulation. As the number of machine stops increases, so does the waste of material and ink associated with restarting the machine.

One attempt to solve the ink conglomerate is to use scraper blades on the printing roller or the like. Although the scraper blades remove ink buildup while the machinery is operating, its use causes premature wear of the surface of the cylinder or roller that supports the fabric. This, in turn, results in increased costs, due to the need to prematurely replace worn equipment.

Another attempt to eliminate the accumulation of ink is to run the layer of material between the fabric and the printing roller. The layer is designed to collect or absorb the ink that passes through the fabric and remove it. This has proven to be very expensive, either because the layer must be replaced with a new one, or because the layer must be wiped of ink before it is run again through the printing apparatus.

Therefore, it is an object of the present invention to provide a method of printing on a substrate which prevents ink from traversing and avoiding the disadvantages of prior art attempts, and such a printed substrate. This object is solved by the method according to independent claim 1, and the substrates according to independent claims 14 and 16.

Other details, aspects and advantageous features of the invention are apparent from the appended claims, the description and the drawings. The claims are intended to be understood as a first, non-limiting, approach to the definition of the invention in general terms.

Accordingly, the present invention, in general, pertains to a process for printing substrates and substrates printed therewith, and more particularly to a one-step, double-substrate printing process, and the substrate that is printed on the substrate. same.

In one form of the present invention, a process is provided for a single pass printing on a double substrate, which includes providing a first constantly moving substrate, which moves the first substrate towards the ink printing station, printing a pattern on the first substrate at the ink printing station, introducing second substrate in continuous movement between the first substrate and the ink printing station, printing a pattern on the second substrate at the ink station, and collecting the ink that traverses the second substrate in the first substrate. The ink printing station may comprise at least one printing cylinder.

In another form of the present invention, a printing substrate is provided which includes a substrate having a printing surface and an opposing inner surface, and an ink pattern printed on the printing surface by simple step printing, in the double substrate.

In yet another form of the present invention, a printed substrate is provided, which is done by means of a process including, providing a first substrate that is constantly moving, moving the first substrate in an ink printing station, printing a pattern in the first substrate at the ink printing station, the introduction of a second substrate in continuous movement between the first substrate and the ink printing station, printing a pattern on the second substrate at the ink printing station, and collecting the ink that passes through the second substrate in the first substrate.

The aforementioned method and other features, aspects and advantages of the present invention, and the manner of achieving them, will be more apparent and the invention itself will be better understood in relation to the following description taken together with the accompanying drawings, wherein: Figure 1 schematically illustrates an apparatus that operates in accordance with the principles of the present invention; Figure 2 illustrates a modification to the apparatus of Figure 1; Y Figure 3 illustrates a fragmentary, cross-sectional view through a portion of the central printing cylinder in Figure 1.

In many of the prior art processes for printing a substrate, portions of ink applied to the substrate can pass through the substrate and be deposited on the surface of, for example, a printing cylinder. This is what is meant by the term "trespass" and causes the ink to accumulate in the impression cylinder. The transfer and accumulation of ink is what results in a poor quality print on the substrate, the transfer of ink to the back of the substrate surface, and poor operating efficiency, due to the detention time It requires to remove the accumulation of ink. Moreover, the transfer of ink causes various undesirable graphic effects on the substrate, such as fuzzy colors, blurred pattern, defective registers, or the like. These unwanted effects are unpleasant for the consumer, and tend to cause a perception of a product of poor quality and performance.

Referring to Figure 1, there is illustrated an apparatus 10 operable in accordance with the principles of the present invention for printing a constantly moving base weight substrate 12, by means of a simple step printing process, with double substrate that virtually eliminates the accumulation of ink in the printing cylinder. The term "substrate" includes, but is not limited to, woven or nonwoven webs, porous films, permeable ink films, paper or composite structures comprising a combination thereof. The term "low basic weight" refers to a substrate that has an inherent propensity for the ink to pass and causes an accumulation of ink in the printing apparatus.

A non-woven substrate is considered a low basic weight substrate, when its basic weight is equal to or less than about 20 grams per square meter. A nonwoven substrate having a basis weight greater than about 20 grams per square meter will be considered a substrate with a higher basis weight.

The term "pattern" when used in reference to ink printing herein includes, but is not limited to, any type of design, brand, figure, identification code, graphic, word, image, or the like.

Desirably, the present invention utilizes a flexographic printing process to provide the proper balance effectiveness, cost, high speed, and high quality. The printing process is suitable for printing substrates of low basic weight, as for example non-woven networks of low basic weight, while maintaining the softness to the touch of the substrate. Flexography is a printing technology that uses a flexible protruding rubber or photopolymer plates to carry the pattern that will be given to the substrate. Flexible plates typically carry a low viscosity ink directly on top of the substrate. Examples of low viscosity inks include inks comprising a non-catalytic urethane block resin and a solvent mixture of up to about 50% by volume of acetate and up to about 75% by volume of glycol ether. The solvent mixture can also comprise up to about 10% by volume of alcohol.

The desired acetates include ethyl acetate, N-propyl acetate, N-butyl acetate, isopropyl acetate, isobutyl acetate, butyl acetate and mixtures thereof.

The desired glycols ethers include ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethyl glycol monoethyl ether, diethyl glycol monopropyl ether, propylene glycol monoethylene ether and mixtures thereof.

Suitable alcohols include ethyl alcohol, isopropyl alcohol, N-propyl alcohol and mixtures thereof.

A more detailed description of the inks suitable for use with the present invention is presented in the U.S. Patent Application Serial Number 08 / 171,309, filed December 20, 1993, which is assigned to the attorney in charge. the present invention, the content thereof is incorporated herein by reference.

Various flexographic printing processes can be used with the present invention, and two of these designs include the design of the central printing cylinder and the stylish stacking design.

The types of plates that can be used with the flexographic process include plates identified as DuPont Cyrel® HL, PQS, HOS, PLS, and LP, which can be obtained commercially from E.I. DuPont de Nemours & Company, Inc., of ilmington, Delaware. Other suitable plates can be obtained commercially from BASF of Clifton, New Jersey, and W.R. Grace & Company of Atlanta, Georgia.

Although flexographic printing is desired, other printing apparatus or combinations of these are also contemplated in the present invention. These other printing apparatuses include screen printing, gravure printing in which the engraved print roller is used, and inkjet printing in which the nozzles spray the drop-by-drop ink selectively by way of a charge electrostatic to form the desired pattern on the substrate. It is desirable that the inks used with this apparatus have a viscosity equal to or less than about 10 centipoise.

The one-step dual-substrate printing process of the present invention is a process that continuously prints substrates of low basic weight. A feature of the present invention is that another substrate, which also requires printing of the ink patterns, serves as a "backing" material to substantially eliminate the accumulation of ink in the printing apparatus. The other desirable substrate has a higher basis weight than the low basis weight substrate. By eliminating ink buildup, the present invention improves the quality of the printing pattern and reduces manufacturing costs.

Referring to Figures 1, 3, a first substrate of a higher basis weight is provided, in continuous movement 14 from a first developed site 16. The substrate 14 includes a printing surface 18 (Fig. 3) and a surface internal in opposition 20. The substrate 14 passes over a series of guide rollers 22, 24, 26, 30 to the first direction section 32 which maintains the proper lateral alignment of the substrate 14 with a printing station 34, and more particularly with a central printing cylinder 36. A roller with pass pressure 38 holds and holds the substrate 14 in contact with the surface 40 of the rotating central printing cylinder 36.

After the roll with pass pressure 38, the substrate 14 is conveyed by the central printing cylinder 36 towards the front ink-printing cylinders 42, 44, 46 which prints a first ink pattern 48 (FIG. 3) on the surface of the ink. printing 18. The central printing cylinder 36 can be rotated in any desirable manner, well known in the art.

Although Figure 1 illustrates three front ink-printing cylinders 42, 44, 46, a greater or lesser number of cylinders can be used to print any desired pattern on the printing surface 18.

Continuing with the reference to Figure 1, a second unwinding location 50 supplies a second, constantly moving low weight substrate 12, above the guide roller 52. The purpose of the guide rollers herein is to maintain the substrates 12, 14 on an appropriate path through the apparatus 10. The substrate 12 continues above the guide rollers 56, 58, 60 to the second direction section 62 which maintains the proper lateral alignment of the substrate 12 with the printing station 34.

From the second direction section 62, the low basis weight substrate 12 passes over the guide roller 64 and a roller with pass pressure 66, which maintains a low basis weight substrate 12 in contact with the first substrate 14. As illustrated in Figure 3, an ink pattern 74 is printed on the printing surface 76 of a low basis weight substrate 12 by the rear ink printing cylinders 68, 70, 72 (Figure 1). The low basis weight substrate 12 also includes an opposing inner surface 78.

Another feature of the present invention is the introduction of a low basis weight substrate 12 into the printing station 34, so that it lies on top of the first substrate 14. Any quantity of ink that penetrates or passes through the substrate of low basic weight 12 will be collected by the first substrate 14. This is illustrated in Figure 3, in which the ink pattern 74, after it has been printed on the low basis weight substrate 12, has at least a portion of this which passes or hits through the low basis weight substrate 12 as a plurality of ink transfers 80. Because the first substrate 14 is between the low basis weight substrate 12 and the surface 40 of the central printing cylinder 36, the Substrate 14 collects and absorbs the amount of ink that passes through 80, thereby eliminating the accumulation of ink on the surface 40 of the central printing cylinder 36. This is important for the present invention as it improves print quality and minimize the costs associated with printing, as explained above.

Another feature of the present invention is the registration of an ink pattern 74 with a practically identical ink pattern 48. Either the pattern in a single color or in several colors, the ink passing through the low weight substrate basic 12 will be collected or absorbed in the same color location in the ink pattern 48 of the first substrate 14. This eliminates any "phantom pattern" on the printing surface 18 of the first substrate 14. This registration is achieved by the linking mechanism or electromagnetic control of the relative positions of the printing cylinders. This type of registration is well known in the printing industry. A type of registration system can be obtained commercially from Hurletron, Inc., of Danville, Illinois After moving the last rear ink printing cylinder 72, the substrates 12 and 14 can be separated from each other with the substrate 14 passing through the first tunnel 82. In the primary tunnel 82, the substrate 14 is subjected to a temperature already a flow of air suitable for drying the substrate 14 and the ink printed therein.

Alternatively or additionally, tunnel 82 may also be a radiation curing unit that is used in conjunction with radiation curable inks. Examples of radiation curing methods include ultraviolet cure, electron beam cure, infrared cure and the like.

After leaving the first tunnel 82, the substrate 14 continues through the first cooling rollers 84, which cool in the substrate 14 to reduce the temperature of the substrate at room temperature.

Then, the substrate 14 passes through a series of guide rollers 86, 88, 90, 92 to be rewound by the first rewinder 93 for subsequent transportation and handling.

Similarly, the low basis weight substrate 12 passes through a second tunnel 94, through the secondary cooling rollers 96, and through a series of guide rollers 98, 100, 102, 104 to be rewound in a second rewinder 106 for subsequent transportation and handling. The tunnel 94 can effect a suitable temperature and air flow, or a method of radiation curing, on the substrate 12.

Alternatively, the two substrates 12, 14 can be kept in contact after the pattern is printed. Then, the substrates will be dried and / or cured together and rolled into a common roll (not shown).

As described, the present invention is envisaged for the printing of pattern ink on at least two substrates, in which one of the substrates is porous, that is, of low basic weight, which can be traversed by the ink. The process of the present invention collects ink that penetrates into an underlying substrate. The two substrates 12, 14 are thus printed in a printing station through a single step 34.

Referring to Figure 2, a modification of the apparatus of Figure 1 is illustrated. In Figure 2, at the separation point of the substrates 12 and 14, a first application station 108, applies a suitable liquid, such as for example a lacquer, to the substrate 14 and a secondary application station 110 applies a suitable liquid, such as a lacquer, to the substrate 12. The lacquers, for example, serve as a protector or preservative of the respective ink patterns. Other liquids can be applied to serve other desired purposes.

The apparatus 10 can be operated within an optimum average speed which is desired between about 2.5 to about 10.2 m / s (about 500 to about 2000 feet per minute), and can be operated for an extended period of time since the Stops caused by the accumulation of ink are eliminated. Although not illustrated, the tension in substrates 12, 14 can be controlled by electro-pneumatic dancer rollers or feedback transducer rollers for speed control devices, which are also well known in the art.

As described above, each substrate may be woven or nonwoven fabric, and desirably may be a polyolefin base network. Polyolefin-based nets include, but are not limited to, woven materials, non-woven materials, fabrics, porous films employing polyolefin base polymers. Examples of these polyolefins are polypropylene and polyethylene, including low density polyethylene, high density and low linear density. However, it should be appreciated that the present invention is not limited to these types of polyolefins, but covers all types of polymers, copolymers and natural fibers. In woven material applications, these materials can be made into continuous fibers, which in turn are woven into a fabric. In non-woven applications, the fibers can be long, generally continuous fibers, such as spunbond fibers, or they can be fibers of shorter loop length, such as those commonly used in carded networks. The fibers can also be melted (meltblow) to form the desired network. These polymers and copolymers can be extruded, melted, or blowed into films for subsequent use in accordance with the present invention including airlaid, wet laid, a solution of spun fiber networks, or similar.

The fibers that are used according to the present invention can be "straight" fibers in that they have the same general polymer or a copolymer composition through. The fibers may also be multipolymer or multicomponent fibers, such as, for example, bicomponent fibers in which at least one component is a polyolefin, such as a polyolefin coating and a polypropylene core fiber or a polyethylene coating and a core fiber Of polyester. In addition to the core or core fiber configurations, other examples of desired fiber cross-sections are the side-by-side, in-island, and eccentric fiber configurations. In addition, fibers with a non-circular cross-section such as "Y" and "X" can be used.

The fibers and / or the networks may have other components and / or treatments. For example, adhesives, waxes, flow modifiers, processing aids and other additives can be used during the formation of fibers or networks. In addition, pigments can be added to the fibers to change the color and other additives can be incorporated into the compositions for making fibers or elastic webs. Finally, mixtures of fibers, as well as one-component or two-component fibers can be combined to form woven or non-woven networks suitable for use with the present invention.

The printed substrate can be used by itself, or in a multiple layer configuration such as a sheet of one or more films and / or woven or non-woven layers. Examples of these multiple layer configurations include film / non-woven laminates, or non-woven / non-woven laminates as a three-ply / spin-cast / spin-layered laminate. By using the multilayer configurations, a variety of properties can be imparted to the laminate including permeability or impermeability.

When a nonwoven is formed, such as fibrous webs of non-woven polyolefin, the size of the fiber and the basic weight of the material may vary according to the particular use. In personal care products and medical fabrics, the typical size of the fiber will vary from about 0.1 to about 10 denier.

While the present invention was described as having a preferred embodiment, it will be understood that it is capable of further modifications. Therefore, it is intended that this application cover any variations, equivalents, uses or adaptations of the invention followed by the general principles thereof, and including variations of the present that result or may result from the known and customary practice in the technique, to which the invention belongs and falls within the limits of the appended claims.

Claims (16)

1. A single step and double substrate printing process, comprising: provide a first substrate that moves constantly, move the first substrate to the printing station, print a pattern on the first substrate in the ink printing station, introduce a second substrate that moves constantly, between the first substrate and the ink printing station, printing a pattern on the second substrate and collecting the ink that passes through the second substrate on the first substrate.

2. The process, as claimed in clause 1, characterized in that it also comprises the registration of the pattern of the first substrate and the pattern of the second substrate.

3. The process, as claimed in clauses 1 or 2, characterized in that it also comprises the drying of the substrates.

4. The process, as claimed in any of the preceding clauses, characterized in that it also comprises the cooling of the substrates.

5. The process, as claimed in any of the preceding clauses, characterized in that it also comprises radiation curing of the substrates.

6. The process, as claimed in any of the preceding clauses, characterized in that it also comprises the separation of the first substrate and the second substrate after the patterns have been printed.

7. The process, as claimed in clause 6, characterized in that it also comprises drying the substrates separately.

8. The process, as claimed in clause 6 or 7, characterized in that it also comprises the separate cooling of the substrates.

9. The process, as claimed in clauses 6 to 8, characterized in that it also comprises the radiation treatment of the substrates, separately.

10. The process, as claimed in any of the previous clauses, characterized in that the printing is a flexographic printing.

11. The process, as claimed in any of the preceding clauses, characterized in that the printing on a rotogravure printing.

12. The process, as claimed in any of the preceding clauses, characterized in that the printing on an inkjet print.

13. The process, as claimed in any of the previous clauses, wherein the second substrate has a basic weight equal to or less than about 20 grams per square meter.

14. A printing substrate, comprising: a substrate comprising a printing surface and an opposing inner surface, and an ink pattern printed on the printing surface by a single-step, double-substrate print.

15. The substrate, as claimed in clause 14, characterized in that the substrate has a basic weight equal to or less than about 20 grams per square meter.

16. A printed substrate, as specifically claimed in clause 14 or 15, which is obtained by means of the process according to any of claims 1 to 13.