Method of applying a 2-component adhesive

Abstract

The present invention is in the field of an improved method of applying a two-component adhesive, wherein the adhesive is provided packaged in a foil, typically one and the same foil, a package comprising said adhesive and an adapted sealing gun, said adapted sealing gun, and specific uses of said package and sealing gun.

Claims

1. A package for use in a single air pressure driven sealing gun, the package comprising a 2-component adhesive, the 2-component adhesive comprising a first component A and a second component B wherein the package comprises two sealed compartments, each compartment being enclosed by a multilayer foil, which is one and the same multilayer foil, wherein the 2-component adhesive further comprises a first fluid selected from a silyl modified polymer, a hybrid polymer, a silane modified polymer, a silicone polymer, a polyurethane, a polysulfide, a polymethylmethacrylate, and combinations thereof, and a second fluid which comprises an activator, wherein the 2-component adhesive comprises the first component: and the second component in a volume ratio of 95:5-50:50.

2. The package according to claim 1, wherein the package comprises at least two welds connecting a top side and a bottom side of the foil in a longitudinal direction of the package therewith forming the two sealed adjacent compartments, and wherein the package comprises a closure at a top and bottom side thereof.

3. The package according to claim 2, wherein the foil comprises multiple layers, and wherein the foil comprises at least one protection layer, and wherein the at least one protection layer is heat sealable, and wherein the foil comprises at least one base layer, and wherein the foil comprises at least one fluid barrier layer, wherein the layers of the foil each individually have a thickness of 5-200 m, and wherein welds have a width of 0.2-10 mm, and wherein the welds are welded at a temperature between 100 C. and 200 C., and wherein the welds are welded during a welding time between 0.1 and 3 seconds, and wherein the layers of the foil each individually have a tensile strength >1 Mpa (ISO 527-2-2012), and >50% elongation at break (ISO 527-1-2), and <3Gpa flexural modulus (ISO 527), and a density of 0.8-1.1 gr/cm (ASTM D1505), and, a melting point of <200 C. (ISO 11357-1/-3), and a melt flow rate @230 C. of 10 gr/10 min (ISO 1133), and, a Charpy index of >50 KJ/m.sup.2 (ISO 197).

4. A single air-pressure-driven sealing gun comprising a package according to claim 1, wherein the package comprises two sealed compartments, each compartment being enclosed by one and the same multilayer foil, wherein the 2-component adhesive comprises a first fluid selected from a silyl modified polymer, a hybrid polymer, a silane modified polymer, a silicone polymer, a polyurethane, a polysulfide, a polymethylmethacrylate, and combinations thereof, and a second fluid winch comprising an activator, and combinations thereof, wherein the 2-component adhesive comprises the first component; and second component in a volume ratio of 95:5-50:50, wherein the package comprises at least two welds connecting a top side and a bottom side of the foil in a longitudinal direction of the package therewith forming the two sealed adjacent compartments, and wherein the package comprises a closure at a top and bottom side thereof, wherein the sealing gun is a one-component sealant gun comprising an air inlet, and an air flow controller, wherein the air flow controller is attached directly to the air inlet of the sealant gun, and wherein the air flow controller is adapted to allow a maximum air flow of 10 1/min, and wherein the air flow controller is selected from an adjustable air flow controller and from a fixed flow controller.

Description

SUMMARY OF FIGURES

(1) FIG. 1: Two examples of Festo GRLO flow controller.

(2) FIG. 2: flow rate as a function of screw turns on two examples of the Festo GRLO flow controller.

(3) FIG. 3: Sealant gun with flow reducer (circle).

(4) FIG. 4a,b Cross section of 2 component flexible packaging: schematic (A) and picture (B).

(5) FIG. 5 shows a picture of a 600 ml 2c packaging.

(6) FIG. 6 shows a sealant gun containing the flexible packaging and the static mixer.

EXAMPLES/EXPERIMENTS

(7) The invention although described in detailed explanatory context may be best understood in conjunction with the accompanying examples and figures.

(8) An example of suitable air-flow reducer is the Festo GRLO series (FIG. 1). FIG. 2 shows the reduced air flow as a function of screw turns from a fully closed position for two examples of flow reducers. It is noted that is rather difficult to reduce air-flow to very low values. The Festo device is considered to be something fundamentally different from pressure controllers, that are usually attached to a sealant gun. The flow reducer, reduces the air flow, but the full pressure is still found to build up. Without a flow reducer, the full pressure would be applied instantaneously, straining the relatively sensitive seals of the 2C sausage, often causing rupture. This has been an almost insurmountable problem in the development of the 2C sausage so far. When applying the present flow reducer, the same pressure is applied during a time period of approximately 5 seconds, after which, there is no influence of the flow reducer on the outflow of the product. Due to the short time delay at the beginning, the seams seem to be able to resist the pressure and rupture occurs far less frequently. The air flow with the optimum balance between time delay and occurrence of rupture, turned out to be approximately 10 l/min. This is a significant reduction of the unrestricted air flow of more than 100 l/min.

(9) No reference was found to flow controllers being used for sealing guns, let alone for application of 2c sausages. Typically, on the contrary, flow control valves are considered to regulate the piston speed of pneumatic drives during advance and return strokes.

(10) Many types of flow reducers are available. Some have restricted flow in both directions, others only in one. They differ in flow rate range and connection types. The example in FIG. 1 has a built-in screw to regulate the air flow, other types of valves are possible. Some types have fixed flow rates, although we were unable to find a flow reducer with a fixed flow rate of 10 l/min. Apparently, this is quite low for air flow rate standards. FIG. 3 shows a picture of such a flow reducer to a sealant gung extruding a 2c sausage.

Experimental

(11) Test Results 2 k Flexible Packaging in Combination with Air Flow Controller

(12) The applicant Saba has developed a new adhesive packaging for its 2 component MS based sealant. FIG. 4A shows a schematic representation of the cross section of such a 2-component package. The dotted lines indicate the location of the welds. The package is made from a single foil. FIG. 4B is a picture of a cross section of such a packaging. FIG. 5 is a picture of the whole 600 ml flexible packaging. The two welding seams are visible on top of the packaging.

(13) The welding temperature and welding time are varied for three types of foil. All foils are laminates of polyethylene (PE) or polypropylene (PP), polyethylene terephthalate (PET) or polyamide (PA) and aluminum (Al). During welding, the PE or PP is molten together. The Al forms the moisture barrier. The three foils do not come from the same supplier. Therefore, there may be differences in type of PE and adhesive used for lamination. The welding temperature was varied between 145 C. and 160 C. and the welding time between 0.45 and 0.8 seconds.

(14) During welding, the packages are simultaneously filled with first (A) component (such as an MS based product) and second (B) component (paste containing the water). The packages are mechanically closed with a clip on both ends. The volume ratio of A:B is 100:10 in the tested packaging.

(15) To test the flexible packaging, the clip is removed from one side. The package is placed in a standard 1 component air pressure driven sealant gun. The open side of the packaging is pointed outside of the gun. A static mixer is attached to an adapter and this is placed on top of the flexible packaging. These elements can be seen in FIG. 6. The adapter and packaging are kept in place by the sealant gun's own locking mechanism; this is the black ring from FIG. 3. Tests were performed with and without an air flow controller. When used, the air flow controller is set up to allow a maximum air flow of 10 L/min and is attached directly to the air inlet of the sealant gun.

(16) During testing, 8 bar air pressure is applied by the sealant gun and the mixed sealant (A and B) comes out of the static mixer. This is continued until the packaging does not contain any adhesive anymore. The empty packaging is then examined for holes along the two welding seams to assess if the seams survived the extrusion process.

Results

(17) The results for foil A, B and C are shown in Tables 1, 2 and 3, respectively. Multiple packages were tested for each time/temperature combination and the results are expressed as % of packaging that did not contain any holes in the welding seams after being exposed to 8 bar of pressure for the time needed to fully empty the packaging. Results are given for the tests carried out with and without the use of a flow controller at the air inlet of the sealant gun.

(18) From Tables 1-3 can be concluded that there is always some failure of the welding seams for all three foils and for all time/temperature combinations when no flow controller is used. When the flow controller is placed between the pressurized air source and the sealant gun, holes in the seams are less frequent. There are several time/temperature combinations where no failure of the seams was observed at all.

(19) TABLE-US-00001 TABLE 1 Results for foil A; effect of welding temperature, welding time and the use of a flow controller. With flow Without flow controller controller (% of packages (% of packages T/t without hole) without hole) 150 0.45 58.3 33.3 0.55 100 28.6 158 0.45 100 86.4 0.5 100 82.8

(20) TABLE-US-00002 TABLE 2 Results for foil B; effect of welding temperature, welding time and the use of a flow controller. With flow Without flow controller (% controller (% of packages of packages T/t without hole) without hole) 145 0.6 90 0 0.75 90.9 0 0.85 42.9 0 150 0.6 75 0 0.75 70 0 0.8 75 0 158 0.45 100 0 160 0.6 62.5 0

(21) TABLE-US-00003 TABLE 3 Results for foil C; effect of welding temperature,welding time and the use of a flow controller. With flow Without flow controller controller (% of packages (% of packages T/t without hole) without hole) 145 0.65 0 0 150 0.6 87.5 50 0.65 96.7 83.3 0.75 100 0 0.8 100 0 160 0.65 100 0
Examples of Foils

(22) In an example the flexible polymeric film layer comprises one or more polymers selected from polypropylenes, polyethylenes, polyethylene terephthalates, polyamides, nylons, or combinations thereof. It is noted that many other polymers, copolymers, and combinations thereof may also be suitable.

(23) A number of polymer layers on either side of the moisture barrier (typically aluminum, but can be any other material with sufficiently low moisture permeation properties) is typically 1 or 2, preferably 2. The outer layers are best heat sealable. The multiple layers are typically connected to one another by an adhesive (polyurethane or other suitable adhesive). The thickness of the adhesive is typically a few microns.

(24) Some foils used so far are the following stacks (thickness in m):

(25) TABLE-US-00004 SABA1 SABA2 SABA3 PE 30 40 60 PET 12 none 12 Alu 6.35 12 8 PET 12 none 12 PE 30 40 60