FI88455C - Lamineringsfoerfarande Foer textile - Google Patents

Abstract

In a process for laminating textiles, wherein a textile web (1) is coated with adhesive in a spraying station (3) and joined with a layer of wadding (8) or with another textile web when passing through a pair of rollers (9), the adhesive used is a moist curing solvent-free polyurethane prepolymer of the mono-component type which is sprayed on the textile web under essentially anhydrous conditions, and then the laminate is allowed to cure in usual atmosphere having normal moisture. Preferably, the adhesive maximum contains 1.5% free isocyanate, and it preferably has a viscosity of about 9000 mPa.s at 130 DEG C, a density of 1.1 and a softening point (ring/ball) of 45 DEG C. Such an adhesive is sprayed at about 190 DEG C, measured at the nozzle tips. The result is a product having excellent properties with respect to washing fastness and softness, just as the drawbacks usually involved in spray lamination are avoided in the production.

Description

1 88455

The present invention relates to a method of laminating textiles as defined in the preamble of claim 1. The method according to the invention is characterized by the features defined in the characterizing part of claim 1.

For use in the manufacture of various garments, in particular T-shirts, sweaters and jogging garments, but also for upholstery materials, car seat covers, quilted fabrics and sleeping bags, weavers manufacture various laminated products in bulk for further processing in sewing shops. Laminated textiles prepared for the above purposes often consist of a textile web with a layer of natural or synthetic wadding attached to it, or it consists of two textile webs with a layer of wadding between them.

Such laminates are produced by a machine that binds 20 individual layers with a suitable adhesive. Usually, the method takes place by spraying an adhesive on the textile web and then combining the sprayed textile web with the wadding in a telecommunication system. The adhesive used is often a solvent-based polyurethane in which the polyurethane and; The solvent mixture contains up to 90% solvent to ensure a composition that makes the adhesive suitable for spraying with spray guns. Even with the most efficient suction system, it is virtually impossible to avoid the presence of harmful concentrations of solvent 30 (often ethyl acetate) in the air during the process, and these high concentrations cause a variety of physical problems such as respiratory irritation, dizziness, headache, and at worst concentration. To this should be added the potential risk of fetal malformations in pregnant women.

2 38455 In addition to these serious problems, the product produced has a strong solvent treatment stamp because the odor of the solvent adheres to the fabric for a long time and is often difficult to wash off.

5 Attempts have been made to solve this problem by using water-based adhesives which, although they do not cause the above-mentioned occupational and health problems, do not produce the desired results in terms of product quality.

10 In order to avoid working with liquid solvents, attempts have been made to laminate textiles to cotton or synthetic wadding with a high-density polyethylene or polypropylene interlayer. The gauze may also be made of other polymers or polymer blends. The polymer 15 acts as a hot melt adhesive when it - placed between the webs to be laminated - is passed through a telecommunications system under controlled compression. The process is good for the environment because no vapors are released when passing through the telecommunication system, and the method can also be carried out easily and quickly, 20 but has the disadvantage that a fairly strong gauze is needed to ensure sufficient washing resistance of the finished laminate. Using gauze that is strong enough to ensure good wash resistance will result in a product that is too stiff and uncomfortable to use.

Attempts have also been made to perform lamination with powder adhesives, often polyamide, polyester, low or high pressure polyethylene, ethylene vinyl acetate copolymer adhesives or various polymer blend adhesives. The powdered adhesive is sprinkled on a textile web, which is then passed through a heating chamber to melt the powder. Upon exiting the heating chamber, the web comprising the adhesive is joined to another web in the calendar.

In addition to dust problems, this method has the disadvantage that it is very difficult to dispense the adhesive powder correctly. 35 Thus, an overdose means that the adhesive wash is too weak, while an overdose causes the powder to sink into the textile web. This results in an undesirably rigid product. In addition, due to the actual dosage method, satisfactory lamination requires the use of an amount of adhesive that is up to 20 times the theoretically required amount.

It has now surprisingly been found that it is possible to avoid all the above-mentioned disadvantages and to obtain a product which is very smooth and durable if the adhesive is a moisture-curable monocomponent polyurethane prepolymer sprayed onto the textile web under substantially anhydrous conditions. After the adhesive-coated textile web is joined to the batt web and the resulting laminate is rolled, the laminate is allowed to cure in a state of normal humidity to obtain a product with very good properties.

The advantage of using this type of adhesive is mainly that polyurethane hotmelt adhesives can be used without any kind of solvent. Second, such adhesives can be used in much smaller amounts than other hot melt adhesives. The method according to the invention uses only 1 -3 g / m 2 of adhesive, while other hot melt adhesives have to be used up to 10 -20 g / m 2, in order to achieve sufficient washing resistance. Such large amounts of adhesive make the laminate rigid and inelastic, while the method according to the invention provides: a flexible and flexible laminate which also has excellent washing resistance.

The adhesives used in the method according to the invention have been known for some time. Thus, they have been used for single-sided gluing of level-30 products made of different foam materials and other gluing with only minor stresses. In addition, they can be used on wood, metal and many plastic materials, as they can in many cases replace contact adhesive.

35 Their usefulness for this purpose is due to the fact that they can be sprayed onto the fine yarns (usually 1/10 mm) of a passing textile web by carefully monitoring the temperature and pressure conditions. By appropriately placing the required number of nozzles, each of which forms a "fan-shaped" pattern on the web, it is practically possible to achieve a completely uniform and optimal spraying of the adhesive.

One very suitable adhesive for this purpose is TivoMelt 9600/41, manufactured by Tivoli Werke AG, Hamburg. This adhesive is a moisture-curable polyurethane prepolymer of the hot-melt type. It contains a maximum of 1.5% free isocyanate (NCO) and no solvent, i.e. a dry matter content of 100%.

The viscosity is about 9000 mPa.s at 130 ° C, the density is about 1.1 and the softening point (ring / ball) is 45 ° C. The flash point of the product is over 200 eC.

It has been found that the best results with this type of adhesive are obtained when sprayed at a temperature of about 190 ° C (measured from the tip of the nozzle). A temperature of about 150 ° C is maintained in the adhesive fiber-20 solution and supply tubes.

Of course, other polyurethane prepolymer type adhesive grades can be used. The working temperature then depends on the viscosity and other properties of the adhesive in question.

The method according to the invention does not impose any special requirements on the type of wadding and textile material used, except that silicone-treated (water-repellent) textiles are not suitable because the adhesive does not adhere well to such material. When it comes to pure, unsaturated textiles, these can be both natural fibers and synthetic fibers. The same applies to cotton, which can be, for example, cotton or polyester.

The invention is more fully described by the following example.

, δ 8,455 p

Example

The figure shows an apparatus suitable for use in carrying out the method according to the invention. The textile web is rolled open from the warehouse 1 and passed through rollers 2 to a spray station 3, where the adhesive is sprayed onto the textile web by a plurality of pressurized nozzles 4 and at a temperature precisely determined by a thermostat, said textile being supported by an endless conveyor belt 5 .

10 The wadding is rolled open continuously from the storage roll 7, the stacking area 8 ensures that the web can be guided evenly to a pair of rollers 9, where it is joined to an adhesive-coated textile web.

Throughout the flow of adhesive from the tank to the hot oven (not shown), the nozzles ensure dry conditions, for example by maintaining a carbon dioxide pressure in the tank, to prevent premature curing.

The laminated web is transferred to a receiving device 10 and allowed to cure after winding in a humidity 20 environment for about 24 hours. The result is an excellent, flexible laminate that is very strong and durable.

If the above-mentioned TivoMelt 9600/41 adhesive is used, the spray temperature must be 190 - 195 eC. This high • 25 temperature is obtained with special nozzles with heating elements embedded in aluminum. The temperature is raised just shortly before the tip of the nozzle and is kept at a lower value, usually about 150 ° C, during the passage through the tubes. The pressure in the nozzles is typically more than two to 30 times the normal pressure prevailing in such nozzles.

The laminated textile web can be passed through the device once more to provide a double-sided textile with a wadding in between.

Claims (3)

88455 6 A method of laminating textiles, in which the textile web (1) is coated with an adhesive and joined to a batt layer (8) or another textile web as it passes through a pair of rollers (9), characterized in that a moisture-curable, solvent-free monocomponent type is used as the adhesive. a polyurethane prepolymer sprayed on the textile web under substantially anhydrous conditions, and the resulting laminate is allowed to cure at normal atmospheric pressure with normal humidity. Process according to Claim 1, characterized in that the adhesive contains at most 1.5% of free isocyanate and has a viscosity of about 9000 at 15 mPa.s at 130 ° C, a density of about 1.1 and a softening point (ring / ball). ) 45 ° C. Method according to Claim 2, characterized in that the adhesive is applied at a temperature of 190 ° C, measured from the tip of the nozzles (4). 7 88455