JPS6037151B2 - How to cure particle coated substrates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of curing uncured adhesives on particle-coated substrates.

The invention is described herein as being used to cure adhesives of mostly flocked materials.

However, the invention is equally applicable to other elongated particles, such as those used in paper and sandpaper. In a well-established method of manufacturing block materials, and even materials such as grade files, elongated particles are attached to a substrate and secured to it with an adhesive; coated with agent. The flock fibers are then deposited onto the substrate by mechanical or electrostatic means. Each fiber stands on the substrate at one end, and the end of the fiber is embedded in the uncured adhesive. As a result, the particular adhesive used must be cured since the flock fibers or particles are only temporarily attached to the substrate (before the adhesive cures). Curing operations are generally carried out in large furnaces. In the furnace, the substrate with the flocked material is passed back and forth until the adhesive appears at the exit end in a cured or polymerized state. Such processing is relatively inefficient, slow, and requires large amounts of energy.

As an example of the latter, a typical curing furnace may be as long as, for example, 30 to 90 feet long, and when water-based adhesives are used, due to their high water content. A typical example is 6 million old TU per unit time while the material is passing through the furnace.
heat is used. If a solvent-based adhesive is used,
Pollution, combustion problems, etc. will occur. (The present invention allows the use of monomers polymerized by electron beam radiation as adhesives.) For tactile substrates, the temperature in the curing oven where the material is processed is between 2400F and 3250F. Temperatures for thermoplastic substrates such as vinyl and styrene may vary between 1/2 of the above temperatures.

Temperatures above 175° C. may cause distortion, wrinkling, or other deleterious effects on some heat-sensitive materials (being processed).

As a result, for such heat-sensitive materials, the curing action is slow, limiting manufacturing. For example, when a vinyl substrate about a few thousandths of an inch thick is flocked in a conventional manner and then subjected to the heat of a curing oven, the vinyl substrate tends to wrinkle during the curing of the adhesive. The resulting materials are generally not suitable for sale and it has therefore been considered impossible to flock such materials. In terms of curing time, due to the low temperatures used, a typical traverse of the floc material through the furnace can be two ships or longer.

The latter number is merely an example. Additionally, if a defect is detected in the cured flocked material, it is now only known after it emerges from the furnace. Since it is not known how far into the curing oven the defects will occur, hundreds of feet of flocked material can be wasted before processing can be properly continued. Yet another problem associated with conventional adhesive curing operations is the production downtime required to clean the oven.

The basic object of the invention is therefore a method for curing adhesives on substrates to which elongated fibers or particles are attached, which uses low energy, is clean and requires minimal downtime. , the thickness of the heat-sensitive substrate is 0.002-
It can be as thin as 0.004 inch (but the particle height is 1 or 3 times higher), and in all cases the adhesive is cured in milliseconds by electron beam radiation. and to provide a method for curing adhesives on substrates in a rapid manner.

It is therefore an object of the present invention to solve many of the prior art problems in the flock processing industry and to provide a novel method which allows for high speed adhesive curing without detrimentally affecting the substrate and the flock material itself. An object of the present invention is to provide an electron beam curing method.

Yet another object of the present invention is to provide a new and improved flocking and related curing method that also has more general applicability.

Additionally, the present invention broadly relates to a method of curing a flock material adhered to a substrate, comprising the steps of: applying a crab electron beam curable adhesive layer onto the substrate; passing the combination of the substrate and bonded flock material through a predetermined area; and applying electron beam energy (at the predetermined area) onto the flock material and adhesive layer. , thereby curing the adhesive layer. Other objectives, features and benefits may be apparent, including:
Some will soon be pointed out.

The invention accordingly includes the steps and order of steps and operational features illustrated in the methods described below, and the scope of application as specified in the claims.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The dimensions of certain parts of the parts shown in the drawings may be modified or exaggerated for clarity and understanding of the invention. Referring to FIG. 1, a production line feed inlet loaf over which textile material, plastic or other sheets to be flocked is transferred, over which the transferred material passes and adheres to the material layer to be processed. rollers that provide a means for applying the agent, an electrostatic flocking device that deposits the flock material in an upright manner onto the adhesive-coated substrate, an electron beam radiation device that cures the adhesive used on the substrate, and a winder.

The key is shown. The inlet roller 2 may be of conventional type, onto which the material to be flocked is transferred;
The workpiece material then passes over rollers 6, where an adhesive 10 of the type that can be "cured" by an electron beam is applied.
It is attached to the substrate by a conventional type of supply tube or other means 8.

To control the thickness of adhesive 14 applied to substrate 4,
A doctor blade 12 is used with roller 6 in a conventional manner. (In the drawings, the presence of adhesive 14 is indicated by thick lines emanating from roller 6 and doctor blade 12.) The thus coated workpiece is then schematically shown as having a container 16. The film is then passed through a conventional flocque applicator.

Container 16 is loaded with flock material 18 of the material to be deposited onto the substrate. At the lower end of the container 16 there is provided a biasing screen 20 of a subordinate nature (in the case of electrostatic flocking) and below the substrate layer a collecting member 22 is provided. Although not shown, in a typical embodiment, high pressure, either AC or DC, is applied between the vessel 16 and the bottom or trough collection member 22 to orient and propel the fall of the fibrous floc material onto the substrate 4. is applied to As is well known in the flocking industry, the flock 18 is deposited on the adhesive coated substrate 14 such that as a result of the application of a voltage, the lower ends of the generally upright elements 23 are embedded in the as yet uncured adhesive. .

All that remains is to cure the adhesive to secure the flocking elements to the substrate. This is where the problem arises.

The flock fibers adhered to the heat-sensitive substrate primarily because of the limitations of the prior art on the application rate and amount of thermal energy that can be applied without deleteriously affecting the heat-sensitive substrate 4 or the flock material 18, 23 itself. or the equivalent cures at a relatively slow rate, e.g. about 30 to 6
This is because it was carried out at 0/min. (This speed is 200
This compares to the curing speed of the present invention, which has been experimentally found to be capable of speeds in excess of feet per minute. ) As previously described, in a conventional process, the workpiece is flocked with an adhesive and then passed through a curing oven where the temperature is maintained between 150 and 3200F.

When the workpiece leaves the flocking device, the adhesive is still uncured. A typical curing furnace is constructed in such a way that the layer of material to be processed is transported back and forth in a circular motion before finally exiting the furnace chamber and reaching the take-up roller; traverse the hardening furnace. The heat transfer to the adhesive is very slow due to the low temperature of the heating chamber and the generally used substrates and organic adhesives and flock materials that do not have high thermal conductivity. As a result, the work material emerges from the exit end of the furnace at a rate of about 20 yards per minute. The present invention contemplates almost instantaneous curing of the adhesive by means of an electron beam when compared to prior art methods.

In industry, it has been considered possible to cure the adhesive under the flock layer by low energy level electron beam radiation. It is known that thin layer coatings can be cured by electron beams. The thickness of such surface coatings typically does not exceed 0.005 inches. For this reason, F. Since the adhesive material has a height (and therefore a vertical thickness J) that prevents electrons from reaching the adhesive, low-energy electron beam radiation can be used to cure the adhesive of the adhesive material. It was believed that it would be possible to use a Using the reference curve, in the prior art, for a floc (particle) height of 0.050 inches, the required electron beam voltage (if the fiber is made of the materials mentioned above) is greater than 50 EV. It appears to be.

It is because of this teaching, well known in the art, that the flocking industry has not considered box beam radiation in solving many problems. The reason why the 150Kev device was not used was because it was expensive, the harmful effects of such energy on the flock and the substrate, and the large amount of shielding required in the device for the dissipation of such energy. It depends on what is needed.

If someone had considered this curve and considered the possibility of using a low-energy electron beam device to harden the resin of the floc adhering material, this idea would have been immediately abandoned as impractical and possible. I would have done it. Considering that the length of the flock fibers can be, for example, up to 0.090 inches, according to the prior art, the effective thickness is 0.090 inches, through which electron beam radiation would not be able to penetrate. . On the other hand, in accordance with the present invention, after exiting the flock deposition apparatus 16-22, the substrate with the flock material 23 deposited thereon traverses an electron beam emitter generally designated by the reference numeral 24.

The device is enclosed within a shielded housing 26. Electron beam equipment is of conventional type, for example the Massachusetts
The device may be a CB15 device manufactured by Energy Sciences, Inc. of Burlington.
Such a device can be adjusted to produce, by way of example, an electron beam energy of 1 chord eV±30% and an electron radiation dose of about 2 megarads 30%, or more if desired. The actual radiation dose required by the material to be cured is a function of the adhesive used, and the actual radiation dose received is determined by the time of electron beam application and the beam intensity. With the above conditions, it has been observed through testing that the flocking adhesive cures without affecting the substrate when the flocking material passes through the electron beam at a speed of approximately 150-200 feet per minute. . As an example, electron beam devices are disclosed in U.S. Pat.
No. 6, and the device is easily designed to apply its energy to elongated particulate fibrous materials in predetermined areas.

As a result, surprisingly and contrary to the teachings of the prior art, the electron beam radiation penetrates the floc material (at the relatively low Kev potentials described above) and the floc on the substrate is embedded in the e-beam hardenability. It turned out that it hit the adhesive.
Within the parameters listed above, it is possible to cure the adhesive bonding the flock material to the substrate very efficiently and practically instantaneously. The above results were obtained with an electron launch port-to-object spacing of approximately 1 inch by 20%. The electron beam device, designated generally by the reference numeral 32, includes a commercially available electron beam generating gun 34 and a shield 36. The shield housing 26 has an outlet duct 28 in which a fan 30 is mounted. The purpose of the fan is to dissipate ozone generated by the electron beam from the shield housing 26. The radiation shielding housing 26 has an entrance slit 38 and an exit slit through which the flocculated material is passed under the electron beam of the electron gun 32. After the material has been bombarded with electrons and the adhesive has cured within the shield housing 26, the flocked material with the adhesive already cured is wound up by take-up rollers 42. As a first example, the rayon woven substrate is 0.004 inch thick Dow 7
331.01 adhesive coated and 3 denier,
Nylon flock fibers approximately 0.030 inches long were electrostatically deposited in a conventional manner.

The adhesive of this combination was cured with a bag layer of CB-15 from Energie Science, Inc. The radiation dose of the CB-15 hammer type electron energy is approximately 17
Adjustments were made so that the weight of female EVs was 2 megarads. Second
As an example, a rubber car window groove material has a thickness of about 0.
0.004 inch of Hawthaway XJ2-4 Female E adhesive (supplied by C.L. Hawthaway & Sons Corporation, Massachusetts) and overlaid with approximately 0.0030 inch long, 3 denier Polyester fibers were electrostatically deposited.

The adhesive was cured by passing the flocked material through radiation from the above-mentioned electron beam generator at a radiation dose of 4 megarads and 17 ev of electron energy.

A CB-15 type device was used. As a third example, a Hawthaway XJ with a vinyl substrate of approximately 0.004 inch is used.
A 5.5 denier rayon fiber approximately 0.50 inches long was electrostatically deposited onto the knife coated with Type 3-149-B adhesive.

The adhesive was cured by passing the flocked material through radiation from the above-described electron beam generator at a radiation dose of 8 megarads and approximately 17 platens of electron energy. A CB-150 type device was also used. After the flocked material is cured and exits the flocking and curing device, it is transferred to take-up rollers 42 and other devices that perform specific operations that are not part of the present invention.

Specific operations include, for example, cutting the flocked material to length, punching flocked patterns from the flocked material, and the like. As another example, similar curing of adhesives on heat-sensitive styrene substrates was successfully performed using the same equipment and adjustments.

Wood and paper substrates have also been used to deposit electron beam curable flock adhesive coatings and layer particles therein. Other types of e-beam curable adhesives such as acrylic epoxies, styrene, vinyl chloride, and saturated polyesters, and other types of flocking materials such as rayon and polyesters, all have radiation dose and energy levels within the above ranges. It has been successfully used in regulation.
The adhesive may be in the range of 0.001-0.008 inches, or within the ranges mentioned above. It is not completely understood at this point why Ryushipeam can cure adhesives underneath a relatively thin layer of upright particles deposited by flocking or other methods. However, it is believed to be a combined function of direct electron radiation and radiation resulting from electron scattering. As a result of the scattering, the direction of the scattered electrons is at an angle with respect to the axis of each particle, resulting in hardening of the adhesive adjacent to each particle and possibly below each particle. Additionally, it is an advantage of the present invention that when the flocculated material with the uncured resin enters the conventional furnace, it disturbs the arrangement of the flocs in the material;
While special care is required until the adhesive is cured during its passage through the oven to avoid introducing discontinuities that would result in rejection of the flocked material, this is not necessary with the present invention. That may be the case. Other advantages of practical and commercial significance are briefly mentioned above.

That is, if, for example, a defect is discovered as the workpiece emerges from a prior art hardening furnace, the flow through the furnace may be traced to determine where the defect originated and what caused it. It is necessary to shut down and inspect all material within the furnace, which can span hundreds of feet. As a result, hundreds of feet of material can have to be wasted due to defects, since defects are only observed at the exit of the workpiece of the curing furnace. In contrast, in the method of the present invention, the material to be processed is
If a detection is found, the only material that must be wasted is approximately 10 feet of material extending from the inlet side to the outlet side of the adhesive curing device. This results in very practical economics since much less material is removed from the production line.
Downtime will also be greatly reduced. As mentioned above, the main advantages are {a} the savings in energy required for curing, and [b' the ability to use adhesives that do not produce 100% solids contamination. Regarding the former, the actual energy required by adhesive curing device 24 is:
Approximately 1 of the energy required for a typical furnace-based curing system
%-10%. Other advantages of the invention are briefly mentioned above.

Thus, there is a long-standing need for an economical and rapid method of manufacturing flocked materials in which very thin pinyl or other thermosetting materials, e.g., 0.004 inches or less in thickness, are used as substrates. Ta. When this type of material is coated with adhesive, flocked in conventional ways, and cured in a typical furnace, the vinyl material will tend to wrinkle considerably from the exit end, even at low furnace temperatures. We know from actual experience that it appears in distorted and distorted forms. Of course, in most cases such wrinkled materials are not suitable for sale. In contrast, according to the invention, it is possible to adhere to a flock of vinyl materials of this type and then cure the adhesive by the method described above without causing any wrinkles on the substrate. Flock attachment device 16-22
As for itself, the Mioro-Sta is manufactured by Indev Incorporated, Machinery and Equipment Division of Rhode Island.
shame. A device such as a two-paper type flock applicator has been found to be suitable.

In the above, the production rate in an apparatus depends on the effective electron beam energy, measured in effective electron beam flow emitted from a particular apparatus, and on the particular adhesive conditions.

There are many adhesives that are cured by electron beam radiation.
And because of their different compositions, these adhesives require different radiation doses for curing. These radiation doses are then measured in megarads. Due to the large number of adhesives available, it is not possible here to enumerate these adhesives and the radiation doses required for specific adhesives. However, the required radiation dose for a particular substance can be found without any inventive effort by the operator of the device. In the United States,
It is estimated that 150 million yards of flocked material is produced each year.

Use of the present invention will result in significant and commercially significant reductions in the cost of manufacturing flocked materials. This savings is due to the lower energy levels required to use electron beam radiation to cure the adhesive resin and the significantly increased manufacturing speed for curing the adhesive, as discussed above. (compared to current curing rates), and due to reduced material wasted if a {c} defect occurs. From the above explanation,
It will be seen that the various objects of the invention have been achieved, and other advantageous results have been obtained.

It is to be understood that the invention is not limited in application to the details of construction and arrangement of parts illustrated in the drawings, as the invention is capable of other embodiments and of being carried out in various ways.

Additionally, it is to be understood that the terms used in the specification are for descriptive purposes only and are not intended to be limiting. Since various modifications may be made to the structure described above without departing from the scope of the invention, all material contained in the above description and shown in the drawings is to be construed in an illustrative and not a limiting sense. It should not be construed in any way. Additionally, the claims are intended to protect all equivalent variations that fall within the spirit and scope of the invention. Note that the present invention is implemented in the following manner.

01 A method according to the claims, in which the electrons have an energy of about 150 Kev±30%.

■ A method as claimed in the claims, wherein the particles have a cross-sectional shape and are spaced apart from each other to provide a path between which electrons can pass and impinge on the adhesive. } A method as claimed in the claims, wherein the electrons have an energy of about 150 Kev±30% and the radiation dose of the electron beam on the layer is in the single digit megarad range.

{4) In the claimed method, the adhesive is made of a synthetic resin plastic selected from acrylic epoxy, styrene, vinyl chloride, unsaturated polyester, and a free radical reaction is used for curing. Consisting of other adhesives and coatings as adhesives.

(5') The method of claim 1, wherein the fibers are about 2 to 5 times thicker than the thickness of the adhesive layer.

(6- In the method described in the above item 'K', the fiber length is in the range of 0.002 inches to 0.25 inches, and the denier is in the range of 0.1 to 100.

'7} The method as claimed in the claims, wherein the heat-sensitive substrate is selected from heat-sensitive synthetic plastics, wood products, cloth, metal-coated plastics and combinations thereof.

[Brief explanation of drawings]

FIG. 1 is a partially cross-sectional side view of a production line using the present invention, and FIG. 2 is a generally accepted diagram showing the penetration of electrons in a material (polyethylene) with a density of 1.06 as a function of electron volts. This is a graph showing a function that is The main structure of the present invention is as follows. 2: Entrance roller, 4: Substrate or workpiece material, 6: Roller, 8: Adhesive supply pipe, 10.14: Adhesive, 16: Container, 18.28: Flock, 24: Electron beam emitting device, 26: Shielding housing, 34: Electron beam generating gun, 3
6: Shielding body, 42: Winding loaf. FIG. l FIG. 2

Claims (1)

[Claims] 1. Elongated particles of a predetermined substance and length,
A blank surface on a substrate on which a plurality of approximately upright elongated particles are disposed, the lower ends of which are embedded in the adhesive, forming a layer with voids between the particles, with a thickness approximately equal to the length of the particles. A method of curing a curing adhesive, in which fewer electrons are required for a non-particulate layer consisting of the same material as said particles and having a thickness equal to its length, but the adhesive does not have said particles. curing an uncured adhesive on a particle-coated substrate comprising applying an electron beam to the particles into the particle layer in a direction toward the adhesive at an energy level at least equal to the energy level required to cure the adhesive; how to.