JP2001527003A - Hot melt adhesive packaging method - Google Patents

Abstract

(57) Abstract: A method for continuous production of a hot melt adhesive, comprising: a) forming a film tube (14) of a plastic material coated on the inside with a non-tacky substance, and b) melting hot in liquid form. Pump or pour the melt adhesive into the tube (14), c) cool the tube (14) with a cooling fluid, seal the tube filled with hot melt adhesive, and d) empty the tube (14). Forming a series of adhesive cartridges, forming a substantially adhesive-free film between each cartridge (28) thus produced, e) solidifying the hot melt adhesive, f) cutting the film (10) covering the adhesive tube (14) and g) peeling the film (10) from the hot melt adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for continuously packaging a hot melt adhesive composition and the resulting adhesive composition in a container.

[0002] Hot melt adhesives are generally applied while in a molten or liquid state and are solid at room temperature. Typically, these adhesives are manufactured in the form of blocks, and due to the nature of these materials, especially pressure-sensitive hot melts, there are problems associated with their handling and packaging. These blocks not only stick to or stick to hand and / or mechanical handling equipment and to each other, but also pick up dust and other contaminants. In addition, when these blocks are placed in a melting pot to produce a coating, such stickiness often poses a hazard to the human operator's hand due to the adhesion of the added blocks. is there. There are many previously proposed methods and apparatus to overcome these problems.

[0003] US Pat. No. 4,054,632 proposes a method for continuously extruding a hot melt adhesive into water, which adhesive forms a skin by extrusion. The extrudate is then cut by a cutter into pillow-shaped blocks, and the core of the block thus produced is slowly solidified in a water bath. This method produces a block of hot melt adhesive under clean conditions. However, this method does not solve the problem of handling blocks of adhesive during manufacture and use.

[0004] Following US Patent No. 4,054,632, a number of methods have been proposed for coating hot melt adhesives with non-stick materials. Many such methods, for example,
French Patent Application No. 2,801,618 and European Patent Application No. 0,74
No. 8,673 discloses lining a series of molds with a non-stick material, then pouring a hot melt adhesive, and then finally applying a film to the surface of the mold to ensure complete coverage of the block. Apply or cover with film. All these methods have the disadvantage that they require a large investment in the use of cooling molds and in equipment which is expensive and difficult to automate.

[0005] EP-A-0,412,867 proposed a method for producing a continuous thick cord which is coated during extrusion. This method requires a significant amount of hardware to ensure that both sides of the flat sheet are covered, and does not properly treat the sides and edges of the sheet and provides opportunities or handling to pick up contaminants. Leave opportunity for bonding to equipment and personnel.

[0006] Another method is proposed in EP-A-0,469,564, in which a piece of hot-melt adhesive is converted into a large bag of plastic material that can be co-melted with the adhesive. Possess. This method makes it possible to produce bags of different masses. However, this method has problems with melting the bags in the melting pot. The problem is that the bag does not always melt with the adhesive, and the trapped air causes the rest of the bag to float to the surface of the melting pot. This application describes overcoming this problem by deflating the bag. However, the packaging can easily be damaged by air leaks, causing the same problems as air in bags,
Ignores the problems associated with handling the above packages. Furthermore, this also requires the use of vacuum packaging equipment, which adds to production costs. This therefore does not provide a suitable solution for handling hot melt adhesives.

US Pat. No. 5,373,682 proposes a method of coating an extruded hot melt adhesive with a non-stick hot melt film. During the extrusion process,
Water or other coolant is constantly sprayed on films that melt at lower temperatures than hot melt adhesives. The resulting extruded tubing is then pinched, cut into separate cartridges, and allowed to cool slowly for later use. This method does not have the co-melting problem of plastic bags described above, but still results in a coating film that is added to the hot melt.

[0008] WO 9700813 proposes a modification of this method in which a series of such cartridges is kept in water until the cartridge cools before cutting.
This method is not necessary to produce a suitable technical result. U.S. Pat. Nos. 5,333,439 and 5,392,592 further propose a method of making a tubular film that covers an extruded series of hot melt adhesives. In U.S. Pat. No. 5,392,592, such films are designed to co-melt with hot melt adhesives. However, in U.S. Pat. No. 5,333,439, the film is designed to be manually removed before adding the block to the melting pot. U.S. Pat. No. 5,333,439 discloses that it is very difficult to produce coated silicon films, and thus the produced blocks are not necessarily coated with non-stick materials and all the usual adhesion problems And the crimping of the tube to make the block does not work.

It is an object of the present invention to provide a method for making a hot melt adhesive that overcomes the above-mentioned problems. Accordingly, the present invention is directed to a method for continuously producing a hot melt adhesive, the method comprising the steps of forming a tube of a plastics material film coated on the inside with a non-stick material, melting the tube in liquid form. Pumping or pouring hot melt adhesive, cooling the tubing with a cooling fluid, forming voids in the tubing to substantially provide adhesive between each cartridge thus produced. Manufacturing a series of adhesive cartridges, cooling the hot melt adhesive, cutting the film coating of the adhesive on the tube, and removing the film from the hot melt adhesive.

This offers the advantage that a film that does not co-melt with the hot melt adhesive can be used, allowing a much wider selection, which can be a more robust and cheaper film to manufacture. This also allows for a wider selection of operating temperatures for hot melt adhesive pumping. Thus, if higher temperatures are used, faster running production is possible. Further, the used film can be removed in the factory and recycled. This is also a non-tacky substance that can be incorporated into the surface of the adhesive without any of the disadvantages of the spraying technique described above, and also ensures that the surface of the hot melt adhesive is coated, so that a small amount of coating is Guarantee what you need. This provides the further advantage that the hot melt adhesive is manufactured in easily sized blocks. In addition, there is no film when the cartridge is placed in the hot melt pot, thus eliminating the problems associated with co-melting the film and hot melt adhesive.

Advantageously, the plastic tube wraps the mandrel around the film,
The seal is formed by forming the seal so that it is not inside the tube thus created. This provides the advantage that when the film is removed, the hot melt adhesive does not carry any film therein, nor does the removal of the film cause damage to the surface of the hot melt adhesive.

In a preferred embodiment, the cutting of the film is performed by cutting means on the opposite side of the tube to the seal. Advantageously, one side of the tube is cut, the other side is torn apart and the film is wound on two spools and the cartridge of hot melt adhesive is removed.

[0013] Advantageously, the method comprises the further step of cooling the series of cartridges by suspending them in a fluid bath which sprays the cooling fluid from above. In a preferred embodiment, the cooling fluid is one selected from the following list: water, chilled glycol, liquid or gaseous nitrogen, compressed carbon dioxide. Preferably, the cooling fluid is water. This has the advantage that a series of hot melt cartridges float on the surface of the water, allowing for a slow and steady cooling of the hot melt adhesive.

Preferably, the film of plastic material is made from one or more of the following substances: polypropylene, nylon and polyurethane. This has the advantage that these film molds are easy to manufacture and recycle and are easily coated with a non-stick material. The method of the present invention can be adapted for packaging most types of hot melt adhesive compositions. In particular, the method is adapted for packaging thermoplastic or thermoset pressure sensitive adhesives where the handling problems are the most severe. By way of example, the methods disclosed herein include synthetic resins,
It can be used to package hot melt adhesives made from polymers and copolymers of rubber, polyethylene, polypropylene, polyurethane, acrylics, vinyl acetate, ethylene vinyl acetate and polyvinyl alcohol.

More detailed examples are: a. Rubber polymers such as monovinyl aromatic hydrocarbons and conjugated dienes such as styrene-butadiene, styrene-butadiene-styrene, styrene-isoprene-styrene, styrene-ethylene-butylene-styrene and styrene-ethylene-propylene-styrene A block copolymer, b. Ethylene-vinyl acetate polymers, other ethylene esters and copolymers, such as ethylene-methacrylate, ethylene-n-butyl acrylate and ethylene-acrylic acid, c. Polyolefins, such as polyethylene and polypropylene, d. Polyvinyl acetate and its random copolymers, e. Polyacrylate, f. Polyamide, g. Polyester, h. Polyvinyl alcohol and its copolymers, i. Polyurethane, j. Polystyrene, k. Polyepoxide, l. A graft copolymer of a vinyl monomer and a polyalkylene oxide polymer, and m. Includes hot melt adhesives made from aldehyde containing resins such as phenol-aldehyde, urea-aldehyde, melamine-aldehyde, and the like.

Most often, the adhesive is compounded with a tackifying resin to improve adhesion and incorporate tackiness into the adhesive. Such resins include, among other materials, (a) natural and modified hydrocarbon resins, (b) polyterpene resins, (c) phenol-modified hydrocarbon resins, (d) cumarone-indene resins, (e) Aliphatic and aromatic petroleum hydrocarbon resins, (f) phthalate esters and (g) hydrogenated hydrocarbons, hydrogenated rosins and hydrogenated rosin esters.

[0017] Optional optional ingredients include diluents such as liquid polybutene or polypropylene, petroleum waxes such as paraffin and microcrystalline wax, polyethylene grease, hydrogenated animal, fish and vegetable fats, mineral oils and synthetic waxes and carbonized Hydrogen oils include, for example, naphthionic or paraffinic mineral oils. Other optional additives may include stabilizers, antioxidants, colorants and fillers. The components and amounts as well as parts of their preparation are well known to those skilled in the art and are described in the literature.

In a preferred embodiment, the film is coated with a release coating that coalesces with the surface of the hot melt adhesive. This offers the advantage that the fusion of the coating with the surface of the hot melt adhesive creates a non-stick coating for the adhesive. In addition, when the cartridge is manufactured, the coating material can be easily sandwiched together, creating a void in which there is little adhesive.

Preferably, the coating is Fischer-Tropsch wax. Advantageously, the Fischer-Tropsch wax is Sasol H1 ™ wax. This has improved anti-stick properties while not having to hold the series of cartridges together. It offers the advantage that a suitable wax coating can be selected.

[0020] Preferably, the formation of the cavity of the tube is performed substantially perpendicular to the cutting direction of the film. Preferably the seal is of the upward fin type. Preferably, the film is a multilayer film. This offers the advantage of giving the film considerable additional strength in all directions. Advantageously, the film comprises two layers of polypropylene bonded such that the weak lines are at right angles to each other. Advantageously, the film may be three layers, including a sandwich of polypropylene, nylon, polypropylene, which offers the advantage that nylon has considerable strength and gives the film a fairly high strength.

An example of an apparatus used to make the hot melt adhesive of the present invention is shown in the accompanying drawings, wherein FIG. 1 shows a schematic diagram of the apparatus. The coated film 10 is fed through a mandrel 12, where the film 10 is fin-sealed to form a tube 10 by tack welding. Tube 14 has a wax coating on the inside and a seal on the outside. Film 14
May be colored blue or red, for example, which helps to check at a later stage that all the film 10 has been removed from the molten hot melt adhesive. The tube 14 is fed to a hot injection molding machine 16 where the molten hot melt adhesive 18 is heated to a temperature above the melting point of the film coating at about 68.95-689.
At 5 kPa (10-100 psi), it is injected into the tube. The injection pressure of the hot melt adhesive limits the speed of the film feed, which depends on the adhesive used. During the injection process, the tube 14 can be constantly sprayed with water by means of a spray device 20 surrounding the tube 14. This ensures that if the plastic material of tube 14 melts at a temperature below the melting point of the adhesive, it will not melt.

The tube 14 is then fed to a boiler 22 where two rollers 24 are hydraulically pressed together to create a minimal adhesive area of the tube 14, An adhesive pillow-like cartridge 28 is created, the size of which is determined by the time delay between each press. The rollers 24 are used to prevent the tube 14 from being broken. This is still facilitated by the hot melt adhesive in the semi-liquid state. Preferably, the film seals with rollers 24
Is approximately 90 °. All devices can still spray water constantly. Voider 22 may be adapted to create adhesive cartridges 28 of various sizes depending on customer requirements.

The series 26 of cartridges 28 then descends while floating in the water bath 30 at the same time that the top surface is sprayed with water. The series 26 folds like a concertina in the water bath 30, thus allowing a wider use of the surface area of the water bath and thus requiring a smaller bath to cool the cartridge 28. A series 26 of cartridges 28 are then removed from the water and passed through a high pressure water cutter 32, where a jet of water cuts the top film 10 approximately opposite the location of the fin seals of the cartridge 28. Jet water is 2 × 1
A pressure of ^{0 7 ~5 × 10 7 Pa (} 200~500 bar), if the use of too high a pressure, jet water is pressed into the film 10 into the cartridge 28. Water cutters have the advantage of following the outline of a series of cartridges 28 without physical contact. Other suitable cutting equipment may be used, for example, a laser.

The film 10 is then peeled from the cartridge 28 by rollers 34, which break the fin seal on the uncut side of the cartridge and wind the film on two winders 36 on either side. The speed of the winder is the same as the production speed. The cartridge 28 is removed from the string 26 and passed to a conveyor where it is sprayed with water to clean any excess material. Finally, the cartridges 28 are passed through a dryer 40, after which they are packaged for supply to customers.

Examples of hot melt adhesives that can be packaged using this method include the following weight percent components: 20% styrenic block copolymer such as SIS (Kraton
D 1107) or Erichon Sol T166 60% hydrocarbon resin or resin blend, such as Escorez 5
300, Kristallex 3115 19% plasticizer, eg mineral oil, eg Odina 68 1% stabilizer package, eg Iiganox 1010, Polygar
d An example of a TNPP film may include a sandwich of the following thickness, with 20 μm thick Sasol H1 wax present, on 47 μm blue polypropylene, 25 μm on 15 μm biaxial nylon: Of polypropylene. The wax covers the film over the entire width of the film, as the wax does not interfere with the fin seal when making the tube.

Other examples of films suitable for use in the method of the present invention include the following -44.
94.9 g / m ² of 50 μm blue tinted coextruded polypropylene, 44.9 g
/ M ² a 50 μm blue tinted coextruded polypropylene film,
1.5 g / m ² adhesive on top of the film, oriented in a different direction to the top film and coated with 20 g / m ² Sasol wax H1. The film is designed to withstand a temperature of 150 ° C. without distortion.

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE, GH, HU, IL, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR , LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZW (72) Inventor Mastie, Jean Bernard Paul France, F-69400 Villefranche sur Soane, Lunational, 792 (72) Inventor Calm, Thierry Fernand, F-69400 Villefranche-sur-Sa ア ー ne, Rudisil Walter, 289 (72) Inventor Lain, Ronald James, France, F-69003 Lyon, Lüdesland, 20F term (reference) 3E056 AA03 CA20 DA05 FH02 FH03 GA05

Claims (15)

[Claims] 1. A method for continuous production of a hot melt adhesive, comprising: a) forming a tube of a film of plastic material lined with a non-stick material; b) forming a molten hot melt adhesive in liquid form. Pumping or pouring the tubing; c) cooling the tubing with a cooling fluid, sealing the tubing filled with hot melt adhesive; and d) applying tubing to the series to produce a series of adhesive cartridges. Forming voids to provide a substantially adhesive-free film between the cartridges thus produced; e) solidifying the hot melt adhesive; Cutting the film coating; g) peeling the film from the hot melt adhesive. 2. The method of claim 1 wherein the tube of plastic material is formed by wrapping a film around the mandrel and forming a seal such that the seal is not inside the tube thus made. . 3. The method according to claim 1, wherein the cutting of the film is performed by cutting means on the opposite side of the tube seal. 4. The method of claim 1, wherein the film is wound on two spools such that one side of the tube is cut and the other side is separated from the hot melt adhesive cartridge from which the seal has been removed. The method described in Crab. 5. The method of any of the preceding claims, comprising the additional step of cooling the series of cartridges by suspending them in a fluid bath that sprays a cooling fluid from above. 6. The cooling fluid of the following list: cooling glycol,
A method according to any of the preceding claims, wherein the method is selected from liquid or gaseous nitrogen, compressed carbon dioxide, water. 7. The film of plastic material comprises:
A method according to any of the preceding claims, made from any of polypropylene, nylon and polyurethane. 8. A method according to any of the preceding claims, wherein the film is coated with a release coating that fuses with the surface of the hot melt adhesive. 9. The method of claim 8, wherein said coating is Fischer-Tropsch wax. 10. A method according to any preceding claim, wherein the voiding of the tube is performed substantially perpendicular to the cutting direction of the film. 11. The method according to any of the preceding claims, wherein the seal is of an upwards fin type. 12. The method according to any of the preceding claims, wherein said film is multilayer. 13. The film comprises two layers of polypropylene, wherein:
13. The method of claim 12, wherein the weak lines are adhered at right angles to each other. 14. The method of claim 12, wherein said film is of three layers including a sandwich of polypropylene, nylon, and polypropylene. 15. A package of a hot melt adhesive produced according to any of the preceding claims.