Plastic bag for fine powders

Plastic bag used for fine powders

Plastic bag for fine powders

Full description

Background of the invention

The present invention relates to the encapsulation of materials in the form of powders. It relates in particular to the formation and filling of bags for use with materials in powder form. Powder products such as filling compounds, cement, cocoa, flour, etc. are traditionally packaged in paper bags for use with high-speed filling and forming machines. However, there are many disadvantages associated with using paper bags. Paper bags are not waterproof. If it is exposed to water or humid conditions, the paper absorbs water and often transfers it to the contents of the bag. If it contains cement or gypsum, for example, the introduction of water allows the material to form, and renders it ineffective for later use. In addition, paper bags lack strength. They puncture or tear relatively easily, leading to spillage and loss of contents.

There have been many attempts to use plastic bags with powder products due to their high strength and water resistance. When non-porous plastic strips are used to prevent water from entering, the air inside the bag when closed is trapped inside. The back pressure created when filling causes the bags to take on balloon-like shapes. In many cases, the bags were not filled to the end so that they would not explode during automatic filling. The bags can be on

Balloon body and additional space for storage and shipping can be unstable when stacked, can compromise the temperature of the seals, and reduce the overall efficiency and cleanliness of the production line. The use of suction to remove excess air often results in suction

Part of the product with air is eliminated.

Processes and equipment that remove excess air from a plastic bag before sealing have evolved, but current technology is limited to no more than four bags per minute. This rate is significantly lower than the rate of ten bags per minute that can be achieved when using paper bags in the traditional forming/filling/sealing process. To overcome this problem, I used bags made of polyvinyl chloride that were perforated with needles to create holes through which the latent air could escape. Even with relatively thin needles that lead to a perforation of about 1000 micrometers, this size is relatively larger when compared to the size of fine powders, which range from 10 micrometers to about 50 micrometers. During packaging and handling can. Powders can come out through the holes, resulting in mess and loss of product. Moreover, needle holes vary greatly in diameter, have rough edges and sometimes block the holes and prevent latent air from escaping. US Patent No. 4,743,123 describes the use of a plastic foil bag with laser-formed exit holes. The thin wall is perforated with laser radiation. The range of holes varies in size from about 50 micrometers to about 150 micrometres. The size of the holes must be chosen to ensure the strength of the film. It is also protected by using holes from moisture at times

The product enters the bag and resides in it. Even when using double-layer bags in which the holes are overlapping and the passage of air and contaminants is winding, they can enter the bag. US Patent No. 6,126,975 describes a bag with a flip flap over micro-perforations. When a non-return or corrugated valve is used, when air leaves the bag, the cap is inflated

The flap is out of its way but the flap snaps onto the pores when air stops escaping from the bag. However, this flap is easily pushed by rubbing against adjacent bags, or can be torn. As with double-layer bags, air, moisture, and product can enter and exit the bag.

Therefore, there is a need in the field for a hard bag for use with powdery materials that can be formed and filled at rates comparable to those provided for paper bags. Another need is to expel the air in the bag at a rapid rate. Still another need is a waterproof bag for use with fine powders that decompose through exposure to moisture.

General description of the invention

The process of the present invention satisfies these and other needs for encapsulating the powdered substance in a plastic bag, and also provides a bag produced by this method. The current process of making and filling a plastic bag includes steps that provide at least one plastic strip; It leads to many tiny holes in the tape; The bag is formed through the use of a bag; The bag is filled with the product in powder form. The bag is fixed; It raises at least one part of the air

Trapped in the bag through the holes; The holes are closed. In a preferred embodiment of the invention, the holes are closed using ultraviolet cured resin.

Another aspect of the present invention relates to a product comprising a bag having a bottom and having at least one side and a top, the bag being formed such that it is fashioned from a plastic strip having a plurality of fine perforations, the top and bottom being secured; The contents of the bag include a powdered product and an amount of air less than that contained inside the bag when the top and bottom are closed, and at least one portion of the air trapped inside the bag is expelled through the tiny holes; A sealant is formed to seal the tiny holes. One aspect of the invention is to perforate at least one part of the bag.

This product and associated production process provides a bag of powder material that is shaped more efficiently and filled with forming/filling/sealing equipment. Instead of having to remove the latent air before closing the bag, the closing step can be performed immediately after filling since the air can be removed after the bag is closed. This frees up the ability to use more conventional forming/filling/sealing equipment and increases the bag filling and closing rate. The air trapped inside the bag is quickly expelled through the tiny holes. The holes are small enough to allow only a tiny amount of the powdery substance to escape from the bag along with the air. Easily released latent air results in bags being made of non-porous components such as plastic, film, and other materials that block air and moisture from entering the

The bag takes up less storage space in containers, delivery vehicles, and warehouses, thus reducing transportation and storage costs.

The use of anti-leak material that seals the micro-perforations prevents air, moisture, and contaminants from entering the bag. It prevents humid air from entering the bag through fine openings, thus preventing it from interacting with baked gypsum, cement, or other hydraulic materials. It also closes the micro-holes. To save the powders inside the bag, it leads to the customer receiving the full weight of the bag that was filled and reduces the chaos that results from the leakage of fine powders when transferring the bags from the transport carts used for delivery and placing them on the warehouse shelves, then transporting them back to the customer’s cart, and finally Until it reaches the storage location

Area of use .

In a preferred embodiment, a laser is used to cut holes in the tape. The laser beam actually rotates so that it produces a small, smooth, round hole in the tape. The size of the hole is controlled so that it is very small and does not contain rough edges that could reduce air flow or cause fine powder to clog the hole. Thus, the use of a laser leads to greater integration and control of fine holes than that provided by the available mechanical equipment used in cutting.

Brief explanation of the drawings

Figure No. (1): is a three-dimensional view of the bag of the present invention.

Figure No. (2): A flow chart of the processes of filling and closing the bag of the present invention.

Detailed description

Referring now to Figures (1) and (2), the powders and art are packaged and stored in a bag. They usually take the design 10 and include fine holes 12. The bag 10 includes a top 14, a pair of sides 15, and a bottom 16, having at least a wall 17 having a surface 18, placed between the top and the bottom. There are many variations of the bag design, depending on the application used and the product to be packaged. Some bags may be suitable for use with the method of the present invention, which does not require that they include all the components described in the bag 10. Bag 10 is filled with the contents of bag 20. For clarification purposes, the value is defined as 14

of the bag as the part of the bag 10 through which the contents of the bag 20 enter the bag before it is closed.

Bag 10 shall be made of a packaging material with sufficient strength to withstand without interruption the forming/filling/sealing operations. It shall be transported and stacked on the shelves, and moved to the place where the contents are used. It is preferable that the packaging material be a plastic tape provided at step 50, and it is preferable that it be on levers. Large rotary equipment used at high speeds. It is preferable that the encapsulated material be waterproof to prevent moisture from entering the bag after closing it. It is highly recommended that the packaging material include at least one portion of plastic tape. Preferred plastics include polyethylene, polyolefin, and thermoplastics. Other suitable plastics include polypropylene,

Nylon, polyester, PVC, and PET such as: MYLAR® polyester tape (EI de Pont de Nemours and Co., Wilmington, DE). Or any plastic strips that can be sealed.

The packaging material optionally consists of one or more layers, including but not limited to paper, plastic or thin strips. It is preferable that the layers be bonded to each other by using any appropriate method, including the use of heat for bonding or adhesion. A specific model of the packaging material is represented by a multi-layer plastic tape. Preferred examples of multi-layer packaging include paper coated with plastic, multi-layer polyethylene plastic tape, or a layer of nylon sandwiched between two layers of polyethylene.

Ethylene. It is preferable to use an internal layer of polyethylene to obtain a good seal. After removing the packaging material at step 52 from the rotating arm and moving it towards the forming/filling/sealing equipment, 12 precise holes are made in the material at step 54. In a preferred embodiment, the micro-perforations 12 are made before the bag is formed 10. The size and number of micro-perforations are determined based on the packaging material,

filling rate, anti-leakage agent) and contents of the bag 20. All the contents of the bag 20 are finer the smaller the fine holes 12 are to contain the contents. For example, powders with an average particle size ranging from about 20 to 30 micrometers are prohibited

micrometers of escape from the bag through micro perforations of up to 150 micrometers. If the contents of bag 20 include a larger average particle size, fine perforations may be used

12 Relatively large.

The maximum size of the micro-holes 12 is controlled through the use of anti-leakage material 22, which closes the micro-holes. When using the anti-leakage material 22, it must be able to fill tiny holes 12 and maintain its consistency until it freezes. As the micro-perforations 12 become larger, the thinner the sealant tape 22 will be until it eventually breaks before solidification. The maximum extent of micro-perforations in the preferred polyethylene resin is about 160 micrometres. Other resins or sealants may have a different maximum hole size.

The minimum size of the 12 microholes is partly determined. At least, by the filling rate of the packaging line (not shown). The 12 smaller micro holes release trapped air at a slower rate. In a few seconds, air can be blown out of an 18-pound bag containing a gypsum-based filling compound and 2,400 tiny 40-micrometer holes. However, a hole capacity of less than 40 micrometers requires an increased number of micro-holes or the time required to empty the trapped air. When the contents of bag 20 include gypsum, or baked gypsum, it is preferable that the fine holes 12 be in the range from about 50 micrometers to 150 micrometres, and more preferably from about 70 micrometers to about 100 micrometres. As the drawings show, the 12 micro perforations are shown for clarity, however, in use at 150 micrometers or less, the 12 micro perforations are likely to be visible to the naked eye. Because the observation of a condensed group of tiny holes 12 is the result of a change in the luminosity of the wall surface 18 at specific angles.

The number and size of the micro-perforations 12 may be varied independently or jointly to meet the various sections. When the size of the micro-perforations 12 is changed, it is preferable to vary their number if necessary to maintain approximately the same surface area across which the trapped air is expelled from the bag 10 At a fixed volume, the number of micro-holes (12) can be changed as long as the air is expelled at a sufficient speed to meet the target filling rate. Changing the sealant may require 22 different sizes and numbers of micro holes. It is preferable to use approximately 1,000 to approximately 3,000 micro-holes 12 for the 18-pound bag 10, where the contents of the bag 20 include a gypsum-based grouting compound. From the above clarifications, someone skilled in the art should be able to compare the properties of the anti-leakage material 22, the morale of the bag 20, the filling rate, and the material used in the packaging in order to determine the appropriate size and number of fine holes 12. We prefer that the 12 micro-perforations be placed on at least one part of the bag. Although fine perforations 12 are effective when immersed over the entire surface 18 of the bag 10, they are more expensive to purchase, more difficult to apply the sealant 22 to the entire bag, and are therefore not preferred. The anti-leak material 22 is also difficult to use when pinholes 12 occur in seams (not shown), near coils 26, or on curved portions 28 of the bag 10. The micro perforations 12 use these areas, but this is not preferable. If necessary, the anti-leakage material 22 can be applied in multiple steps until all surfaces of the bag 10 are satisfactorily coated. Therefore, it is preferable to place the micro perforations 12 on one surface of the bag 10. It is more preferable that the fine holes 12 be placed on a portion of the bag 10 so that they can be easily accessed for

Use of anti-leakage material 22, and it is relatively flat. Thus the 17 walls of the bag 10 represent the preferred locations for the micro-perforations 12.

The number and density of the micro-perforations 12 will determine the size of the portion of the bag's surface 18 on which the micro-perforations 12 are located. Surface areas as small as one inch are used to cover the micro-perforations 12. Densities ranging from about 10 to about 800 of micro-perforations 12 per square inch are preferred. For use in a 10-pound capacity bag filler compound as shown, only approximately 3 to 6 square inches are used for the 2400 micro holes. The minimum preferred density is that which fits the micro-perforations 12 on the surface 18 of the bag 10, while the maximum density is that which does not satisfactorily correspond to the strength of the bag in the vicinity of the micro-perforations. It is preferable for the micro-perforations 12 to be regularly spaced but it is not necessary to achieve that.

All micro-perforations 12 need not be limited to one part of the bag 10. The micro-perforations 12 can be formed in any direction, any shape, or a combination of desired shapes. For example, the 12 micro-perforations can be shaped to represent a brand name, a group logo, or both. It is useful to use two or more parts for fine perforations 12, for example one could be used on each wall 17 of the bag 10. It is preferable to use micro holes 12 mainly so that they are circular on the surface of the wall 18. However, it does not require a specific shape as long as the edges are smooth and the shape does not cause blocking of the micro pores.

Preferably, the 12 micro holes are formed using a programmed laser (not shown), although any method can be used that produces 12 micro holes of appropriate size and smooth edges. It is preferable that the laser be 80 watts and be computer-controlled carbon dioxide. It is preferable to The laser is programmed to create 12 micro-holes of the appropriate shape, size, and density. Processes for laser notching substrates such as that described in U.S. Patent Nos. 5,630,308 and 5,158,499 incorporated herein by reference are suitable for use with the invention.

a

Laser procedures are available from Parallax Technology, Inc. of Waltham, MA. In step 62 when the sides 15 and the bottom 16 of the bag 10 are closed, the bag is filled with the contents 20 and air. Although the bag 10 is particularly well suited for use with fine powders, it is useful for use in any product for which the expulsion of entrained air is beneficial. For example, coffee represents a suitable contents of 20 for bag 10, as it is fresher when exposed to less air. However, the greatest benefit is achieved when the bag 10 is used with contents 20 including cement, gypsum, cocoa, filling compounds, calcium carbonate, flour, lime, and the like. Any method of filling bag 10 is suitable. If the bag 10 is formed around the cone in step 60, the cone is optionally used to fill the bag in step 62, and is removed only after the bag is filled.

When moisture is harmful to the contents of bag 20, a dehumidifier or desiccant is optionally added to bag 10. The desiccant is a moisture scavenger and operates in any form, including a package or tablet. Silica gel is often used to remove moisture in packaging. It is appropriate to add the desiccant to bag 10 either before, with or after the contents of bag 20. After filling, the top 14 of the bag 10 is closed and secured in step 64 using any method known in the art including use of at least one of the methods of heat sealing, use of glue, folding, pinning, and sealing each of the contents of the bag 20, and entrained air. The backpressure generated by the filling process may, although not required, introduce an excess amount of air into the bag 10. Immediately after closing the bag 10 may appear inflated with one or more walls 17 outward.

When closing the bag 10, it is desirable to effectively expel the trapped air from the bag 10 at step 66 through the tiny holes 12. At least one portion of the trapped air is expelled, sufficient to allow the bags to be stable and compressible. When stacked. Although some air leaves the bag without the use of any external force, it is preferable to expel it

Air quickly to maintain a comparable filling rate to paper bags.

It is preferable for the bag 10 to be compressed at step 66, and at least one portion of the trapped air is expelled, although any method that causes air to exit the bag through the tiny holes 12 is useful. Shaking the bag 10, for example using it on a vibrating conveyor belt, collects the air. It is trapped at the highest part of the bag 10, and if it is oriented so that the pinholes are 12

In this position, at least some of the air will exit through the tiny holes. Preferred equipment (not shown) for removing trapped air includes a vibrating conveyor, a bag-flattening conveyor, a piston-driven plate, rotary discs for pinching, or any suitable tool. Using pressure with the conveyor that flattens the bag, the plate that operates with a piston, and the rotating arms that are used to pinch the surface 18 of the bag 10, he works to push it inward toward the center of the bag. When pressure is used, the trapped air is pushed out of the bag through the 12 tiny holes.

It is preferable to design and place the air extraction equipment, the bag 10, and the micro-perforations 12 so that the equipment does not obstruct the escape of air through the micro-perforations. If, for example, the piston-driven plate in step 66 is used to expel entrapped air from the bag 10, the portion of the plate above the microperforations 12 optionally and directly includes one or more openings to allow air to escape.

If necessary, a dust collection system (not shown) can be used with an air extraction device to prevent the product from escaping into the surrounding area. Optionally, trapped air is expelled from the surrounding area using a suction device. Fine particles of powder that have escaped from the entrained air may be removed using any appropriate cleaning technology, including but not limited to a filter or the use of electrostatic precipitation. The part of the trapped air at step 66 is removed, followed by the provision of anti-deposition material 22 at step 68, and the micro holes 12 at step 74 are closed to prevent air and moisture from being present in

10. The surrounding area and to prevent them from entering the bag again. Any material is optionally available

Leak-proof 22 at step 68 to seal micro-holes 12 including but not limited to the use of resins and adhesives. Hot melt adhesives are useful counter materials22 for certain types of packaging materials. Naturally synthetic resins can be used, including water-based resins, solvent-based resins, and resins that cure when exposed to specific frequencies such as ultraviolet radiation. The anti-leakage material 22 must have sufficient adhesion to the packing material, and the strength of the tape must also be available to fill the gap defined by the micro-perforations 12, and maintain the integrity of the tape until it solidifies, resulting in closing the micro-perforations.

Many sealants 22 can be customized to create as many different finishes as required. Resin 22 can be made to match the color and/or texture of the bag and will therefore be blended into bag 10. If a different design is preferred, Resin 22 can be colored to match or contrast the colors to create logos or patterns as preferred. The resin 22 can thus become part of the commercial design of the product 20, and contribute as desired to the overall appearance of the bag 10.

Rapid curing resins are suitable for use in sealing micro-holes12, especially light-curing resins. These resins 22 can easily be applied with a brush and harden very slowly until they are exposed to a specific frequency of light. UV curing resins are more preferred as they harden when exposed to ultraviolet wavelengths. The UV light begins

Polymerization reactions that cross-link with the oligomer to form a strong, rigid surface. Examples of UV curing resins include polyurethane compounds, acrylic compounds, acrylic urethane compounds, epoxy and combinations thereof. The preferred UV curing resins are Apsqure 90-3010, marketed by Applied Polymer.

System, Inc. of Schaumburg IL. This resin contains about 40 to 60%

by weight of acrylic laced with acrylic acid (UCB Surface Speacialists, Smyrna, GA), from about 20 to about 40% by weight of acrylate-isoboron (UCB Surface Specialists, Smyrna, GA), and from about 10 to about 20% by weight of Trimethylacrylate

Incorporate triethyl oxyethyl (UCB Surface Specialistsm Smyrna, GA), and about 5 to about 10 wt% of the photoinitiator coating. When choosing an anti-leakage 22, many factors must be taken into consideration. The anti-leakage material 22 is preferably compatible with the packaging material, sealing the holes 12 without using essentially fusing or dissolving the parts of the bag 10. If it is required to combine the anti-leakage material 22 with the form of the material used in the packaging, other desirable features of the anti-leakage material are that it includes a similar texture surface, and flexibility like that of the material used in the packaging. These characteristics also include that it dries with a number A few bubbles, or some defects on the surface. It is preferable that the anti-sealant material has sufficient adhesion to the packing material so that it does not separate into flakes, or does not spread after drying. Since it is difficult to keep the surface of the powder bag clear in this environment, it is also preferable that the adhesion between the sealant and the bag not be impeded by the presence of

Powder on the surface of the bag while doing caulking. Since bags 10 for some products such as gypsum or cement are stored under a variety of conditions, the properties stated above must be maintained over a higher temperature range from about 32°F to about 110°F.

Fahrenheit.

If the contents of the bag 20 are sensitive to exposure to water or moisture, it is preferable that the leak-proof material 22 be waterproof so that moisture is prevented from entering the bag 10 due to the passage of time through the holes 12. One of the choices used in the leakproof and waterproof material22 is its ability to withstand a direct splash of water from a commonly used sink for 30 seconds without damaging the contents20 of the bag10.

Before applying the sealant 22, several resins are combined using an optional photoinitiator in step 70. Upon exposure to specific frequencies of light, the photoinitiator disintegrates into free radical compounds that begin to polymerize the resin to form a strong, rigid plastic film. Any photoinitiator is useful in this invention that initiates the polymerization in the chosen resin 22, which is compatible with the packaging material. Preferred photoinitiators include acetophenone, benzophenone, and mixtures thereof. The preferred resin) comprises approximately 5 to 10% of the photoinitiator coating available from Aldrich Chemical of Milwaukee, WI. Packaging includes

A combination of acetophenone, benzophenone as an optical initiator, and a remaining amount of optical brightener. Some resins 22 used do not require curing, such as Flexcure Resins provided by Ashland Specialy

Chemical, Dublin OH.

Some photoinitiators 22 turn yellow over time. If it is necessary for the color to remain in its original state, the photoinitiator should be chosen to achieve this goal. Adding an optional UV absorber or optical brightener also reduces the yellowing caused by byproducts of excessive UV exposure. Another optional component of resin 22 is the catalytic converter which is added in step 72. Photoinitiators can form free radical compounds by methods other than exposure to light. The catalytic converter absorbs energy at different wavelengths to a greater extent than the photoinitiator, and then transfers the energy. The photoinitiator effectively transfers the absorption spectrum of the photoinitiator. The catalytic converter is useful in improving processing speed and efficiency in some circumstances. Steps 70 and, optionally, 72 may occur before step 68 where UV-curable resin 22 is available, where the manufacturer has previously added the photoinitiator and catalytic converter. After the resin 22 has been prepared in steps 68, 70, and 72 and is ready for use, it can be used in step 74 with the part or parts of the bag 10 containing the fine holes 12. Any application method may be used for this, including, but not limited to, brushing, or Rotating arms, coating, spraying, gluing or leveling. Because the resin 22 will seal around the individual particles that remain on the surface of the bag 18, it is not necessary to clean the bag 10 before applying the resin 22. However a sufficient portion of the bag 10 must be available to adhere the resin 22.

Once the resin 22 is applied to the bag 10, it hardens to form seals on the fine holes 12 in step 76. Some sealants simply air dry to a solid surface. When exposed to an ultraviolet radiation source (not shown) in step 76, the resin 22 and the photoinitiator react in seconds to produce and seal solid micro-holes 12. It is preferable that the cured resin used in UV rays be exposed to a UV source for a sufficient time in order to form a permanent seal on the micro-holes 12. The exact time of the reaction will depend on the source of radiation, the distance between the source and the bag 10, as well as the specific resin 22 and photoinitiator used. It is preferable to use the F300S bulb model

From UV systems, Inc., Gaithersburg, MD, as the radiation source. It is typically done at

Exposure to 300 watts of focused light system results in reaction times of 3 to 4

Seconds. When using resin 22 in areas such as bends in the bag 10, incomplete curing can occur due to insufficient exposure to light. Therefore the UV source must be positioned so that all areas of the resin are coated until the desired hardness is achieved. Additional UV sources, or a source with a higher electrical power, may also be used to properly cure all of the resin 22. Lower wattage sources can also be used but require extended processing times. When the resin 22 is used and properly cured, the tiny holes 12 are sealed to prevent air and moisture from entering the bag 10. In the following examples the plastic bags were made to be tested as alternative packaging to Easy Sand's 18 lb (8.7 kg) capacity bags of the type that can Prepare it with filler compound (USG Corporation, Chicago, IL). Tiny holes were formed in the coated material using...

Laser pre-formed the bags, then the bags were formed by heat sealing the wall layer to form a tube, then one end was sealed from the bottom to form the bottom of the bag. The bag is filled with filler compound powder. The top of the bag was then heat sealed and the air trapped in the bag was expelled through a combination of vibration and rotating compression arms that expelled the trapped air through tiny holes. After removing the air, a sealant is applied with fine holes through a brush and left to solidify.

During testing, the bags were kept at different temperatures and humidity levels to vary the storage conditions. While the bags cycled between two extremes of hotness and coldness, the bags were transferred once a day to the opposite condition except on weekends. When the temperature and humidity testing was completed, the bags were completely emptied of their contents, sifted through a screening device with up to 12 eyes, and then the remaining masses were weighed.

.

Example No. (1)

Three-layer plastic bags made of polyethylene (Plassein Inernational) were prepared

Packing, Willington, CT) has 125 µm micro perforations along the length of each side of the bag and the micro perforations are made closely spaced in a thin roll that runs along the sides of the package. The bags were filled with a 12.5 lb (5.7 kg) mixture of packing compound, sealed, the trapped air expelled, and then heat sealed at the top to seal the bag. GLUEFAST ethyl acrylate/2-ethylhexyl acrylate polymer anti-leakage agent has been developed.

Joint (Hughes Enterprises, Trenton, NJ) using a brush, and left to air dry.

Aging tests have been conducted to determine whether the use of anti-leakage is beneficial over time. The bags were either kept at constant temperature and humidity, or cycled between several temperature and humidity conditions for up to 11 days. I used the following test:

<img file="SA2263B1_D0001.tif" />

The use of anti-leak material on a type A plastic bag reduces the formation of lumps during rotation between two extremes of temperature and humidity compared to both a paper bag, and a bag that has fine holes and does not have an anti-leak material.

Example No. (2)

Polyethylene bags of the type and source shown in Example No. (1) were obtained for the test, and approximately 2,400 micro-holes were made in a strip measuring 1 x 4 (2.5 cm x 10 cm) along the front of the bag. The amplitude of all microholes was approximately 100 μm.

The 18-pound bags were filled with a mixture of Easy Sand grouting compound, and the top was sealed using heat. The anti-leak material, which is a cured resin, has been applied

Apsqure with UV rays (Applied Polymer Systems, Schaumburg, IL)

Using a brush. The perforated part was not cleaned before applying the material in order to remove dust from the filling compound from the front surface of the bag. While the travel was 42 ft/min (0.2 m/s), the bags crossed about 6 inches (15 cm) of the 300 watts/square inch (46 watts/cm2) of the UV source located below. The following tests demonstrate the effectiveness of the UV-cured resin on the micro-holes of a plastic bag containing an Easy Sand filler compound.

<img file="SA2263B1_D0002.tif" />

Two different types of ultraviolet lamps were made: H-spectrum lamps and D-spectrum lamps. The H-spectrum lamp is designed for clean solutions, while the D-spectrum lamp is used in thicker, opaque solutions. The column indicated by samples of a photoblocker that uses ultraviolet rays has been shown in the column. 'A natural or controlled concentration (CON) is used to differentiate them from those that have an additional amount (XPI) of photoinhibitor. Samples 4, 5, and 6 were passed over the lamp

UV radiation is used twice to ensure that the resin has fully cured, and to determine the effects of UV exposure. An additional photoinhibitor was added to the samples. In addition to the test conditions 1, 2, and 3 shown in Example No. (1), some of the previous samples were tested under additional conditions described below. Test condition 4: 40°F (5°C) - 80% relative humidity, continuous. Test condition 5: 75°F (24°C) -30% relative humidity, continuous. Test condition 6: Total immersion in water.

Test condition 7: Cycle between 40°F (5°C) - 80% RH, and 30°F (0°C) - 0% RH.

The previous samples were tested under the conditions shown in the table below.

<img file="SA2263B1_D0003.tif" />

These tests demonstrate that the anti-sediment material used in the micro-perforations effectively reduced the formation of lumps and wicked moisture away from the bags under a variety of conditions. The sample was completely immersed 7 in 1 in water by placing the bag in a 30-gallon (111 L) container filled with water to test how well the seal held up against water. The bag was lifted from the water when...

Bubbles confirm there is a leak from the bag. When the bag was opened, both ends were hydrated, yet the powder beneath the fine holes was dry and free of lumps. This indicates that the leakage was caused by the caulk using heat at either end and not through the tiny holes. The leakage of the powder in the two bags - samples 5 and 6 - returned to the corners of the bag and was not caused by a failure in the seals of the tiny holes.

The two bags, aged by cycling between two extremes of high and low temperatures and humidity, showed the disintegration of the resin used in the ultraviolet rays into a hair-like line resembling spider webs. Although the appearance of the crumble was not beautiful, it did not affect the adhesion of the resin to the surface of the bag, and did not lead to any leaks in the powder. Although the present invention has been illustrated by giving particular embodiments thereof, those skilled in the art will recognize that changes and modifications may be made without departing from the scope of this invention in its broader aspects, as demonstrated by the claims.