JPH02191167A - Seal container for storing substance sensitive to moisture component and air and use thereof - Google Patents

Abstract

PURPOSE: To store moisture or air sensitive materials and takes them out from the container by using a sealing material that covers the whole surface of a moisture or air sensitive material and that can be easily softened by application of heat. CONSTITUTION: A hot melt adhesive 12 in a container 10 is covered with a seal 14, which is selected among materials of kinds with small permeability for water vapor and convertible into liquid by applying heat. The seal 14 is viscous at room temperature, covers the upper face of the hot melt adhesive 12, flows outward, comes into contact with the inner face of sidewall of the container 10 to seal. When taking out moisture setting thermoplastic adhesive from a drum, a lid 16 is removed, and as a heated plate moves downward, space 30 is first evacuated through a passage 28 and the seal 14 is liquefied to be removed through the passage 28 by continuing the downward move. When all of the seal is evacuated, a valve on the passage 28 is closed and the heated plate is fixed on the upper face of the thermoplastic substance 12 in solid in the drum. So as to let the thermoplastic substance 12 flow out through a passage 26 without exposure to moisture, the thermoplastic substance 12 is heated to be liquefied.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to means for storing moisture or air sensitive substances in containers and to methods for removing the substances from containers.

BACKGROUND OF THE INVENTION Moisture and air sensitive or reactive materials are often transported to the point of use in drums or pails, and the materials are not very viscous. If the substance is very viscous or a meltable solid, it may be removed from the container by a simple pump or by a heating plate (
It is removed from the container with a special type of pump that includes a heating platen. In the latter case, a hot plate is placed against the exposed top layer of the material stored in the container to make it plastic, and the softened material can then flow out through the outlet and be used as intended. can. Some of such materials have high sensitivity to exposure to moisture or air, and some are even rendered useless by such exposure to atmospheric moisture. . Bostick Supergrip 2000 contains reactive incyanate or siloxane end groups.
, Fuller Ipathe
rm), Ceca Rectico
l) and Reicold Swift
A typical example is a moisture curable polymeric hot melt adhesive sold commercially as 5w1ft). These polymeric materials are viscous liquids at room temperature and remain that way until exposed to moisture, at which point the incyanate or siloxane groups react and the liquid The adhesive is cross-linked to make it thermoset in nature.

When packaging these types of polymeric materials for storage and transport for trade, exposure to moisture must be avoided or heating plates may be used to remove the stored materials from the drum. The aforementioned undesirable reactions can occur on the exposed surfaces of the storage material, which prevents pumping and emptying of the container. Traditionally, more or less successful sealing means have been used in which the exposed layer of moisture-sensitive storage material is covered with a layer of carbon dioxide, or alternatively, a desiccant may be contained over the exposed layer of storage material within the drum. Proposed. For some reason, neither of the currently available sealing means is suitable for situations where air- or moisture-reactive substances must be stored in a container for eventual cooperation with a pumping means and then transported to the point of use. It has been found that it is not completely satisfactory under all of the variable conditions that are known to exist.

SUMMARY OF THE INVENTION The procedures disclosed herein provide for a container that can be adapted to cooperate with a heating plate for pumping moisture or air sensitive thermoplastic materials. It is therefore particularly suitable for storing the above-mentioned substances.

It provides a completely satisfactory seal that can be removed using conventional extraction equipment and that can be used to protect the stored material from exposure to any moisture, including atmospheric water vapor. provide. Even though this seal is in intimate sealing contact with the entire exposed upper layer of storage material and the inner surface of the side wall of the container, its composition or viscosity is such that it does not dissolve in the storage material with which it contacts. . That is, the sealing material should be chemically insoluble in moisture- or air-sensitive substances, including solids of such high viscosity that they do not dissolve in any significant way. It should be. In one embodiment, it must be able to be pumped out at room temperature, or it must be able to be heated to allow it to be pumped out. Another and most important property of the sealing material is that it must be impermeable to air and water vapor.

To achieve this, the air- or moisture-sensitive thermoplastic material to be stored is filled into the container or drum in which it is to be stored, and this filling is, of course, preferably carried out with air or moisture-sensitive thermoplastic material to be stored. Performed without exposure to moisture. After the container filling process is completed, a viscous sealing material is poured onto the exposed upper layer of material within the container. The viscous seal material covers the entire surface of the air or moisture sensitive material and flows into contact with the inner surface of the side wall of the container.

This sealing layer is preferably very viscous at room temperature, but can be easily softened by applying heat.

In another embodiment of the invention, a thermosetting liquid polymer system may be used as the sealing material as long as it is insoluble or immiscible with the primary thermoplastic in the drum. Moisture curable Bostik Supergrip 2000 can be used with materials such as polyurethanes, polyureas, polysiloxanes and others of the kind.
This is an example of such a polymer. If the covering or sealing material is comprised of such a polymer, it is stripped from the moisture or air sensitive material immediately prior to use. A peelable covering may be made from a thermoplastic polymer so long as it has sufficient cohesive strength to permit peeling and removal from the underlying material it protects. Thermoplastic polymers suitable as strippable coatings include, for example, butadiene-styrene copolymers, copolyesteretheramidestyrene-isoprene copolymers, butadiene-styrene block copolymers, polystyrene-polybutadiene copolymers, and A mixture of polypropylene and a cured ethylene-propylene terpolymer is included.

Yet another embodiment is the use of a separation sheet between the material to be protected and the covering or sealing material. The separating sheet should have releasable properties on at least one side thereof, and that side is the side on which it comes into contact with the substance to be protected. The sheet itself may be made from a material inherently possessing good release properties, such as polytetrafluoroethylene or polyethylene sheet material, or it may be made from other sheet materials such as aluminum foil, polyester film, kraft paper or the like. It may be of any other type of material and may be coated on at least one side with a release coating such as polytetrafluoroethylene, silicone or polyethylene.

Such a seal adequately protects air or moisture sensitive materials from any exposure to air or water vapor during storage and transportation. In use, the sealing layer can be removed first if it is thermoplastic, using a pump preferably equipped with a heater, and heated without removing it from the container after the seal has been released. The plate can be brought into direct contact with the top surface of the main material and then the material can be heated and pumped out of the container.

The examples listed below concern moisture or air sensitive substances that are solid at room temperature or are so viscous that they must be heated before they can be easily removed from the container. By way of example, the present invention also encompasses moisture or air sensitive materials that are sufficiently flowable at room temperature and can be removed without heating. Examples of these latter materials include polyisocyanates and reactive polydimethylsiloxanes, as well as any polymeric backbone containing moisture-active incyanate or dimethylsiloxane groups. It will be done.

〔Example〕

To cooperate with the hot plate, fill it to its normal height with a moisture sensitive hot melt adhesive material 12 (which is thermoplastic unless exposed to moisture) as will be more fully apparent below. A container IO is shown in FIG. This adhesive material 12 is, for example, one of the moisture curable hot melt adhesives mentioned above. Certain moisture or air sensitive chemicals stored within the container must be immiscible with and insoluble in the sealing material, and if it is solid or highly viscous. is not critical, except that it must be heat softenable.

The hot melt adhesive is covered with a seal 14. This layer is selected from a class of materials with low water vapor permeability and is also immiscible with and insoluble in the thermoplastic. Another very important property is that it should or should be compatible at all to be applied as a liquid to the top surface of the storage material, and if the heating plate is pressed downwards against it (see Figure 2). It can be made into a liquid by applying heat. Preferably, the seal 14 is viscous at room temperature and is poured onto the top surface of the hot melt adhesive 12 to cover it and flow outwardly to contact and seal the inner surface of the sidewall of the container IO. make it possible.

The seal may be, for example, any polyhydrocarbon or similar product having the properties outlined above.

Seals include εnerpar, sold by the British Petroleum Company, and Flexcon, sold by Exxon Corporation.
mineral oils with high paraffin content, such as Exxon Corporation's Cor
ay) 22, British Petroleum Company's Enerthene mineral oil with high naphthene content, or
ls) Company's Best Wax (Vestowa
x), a thermoplastic rubber such as Kraton sold by Shell Corporation, or a polyhydrocarbon such as EPDM from Exxon Corporation.

Preferably, the seal 14 is a viscous liquid at room temperature, has a low water vapor transmission rate, and has a water content of 1 p.
A layer of polyisobutylene that is less than pm. This layer 1
4 over the exposed top surface of the hot melt adhesive material 12, with a layer of 10 to 50 mm if desired in conditions where the top layer of the thermoplastic material may be non-uniform. It is expanded to. The viscous nature of the preferred polyisobutylene maintains a perfect moisture-tight seal of the stored material even if the container may be tilted for short periods of time, such as during transportation.

The container 10 is also provided with a conventional lid 16 which must be removed to expose the contents of the drum. If the moisture-curing thermoplastic adhesive is to be removed from the drum for use, the lid 16 can be removed and supported by a piston rond 20 so that it can be advanced downwardly into the drum, such as a Nordson adhesive. Cy, using heating plate 18 of bulk melter #506. The hot plate fits snugly against the inner surface of the side wall of the drum and has an annular gasket 22 around its outer periphery to prevent air from entering the drum.

The heating plate has two branch pipes 26 extending upward from its bottom surface.
and 28, and a conduit 26.
and 28 each have a valve. As the hot plate moves downward, the space 30 is first evacuated through the passage 28, and it continues its downward movement to liquefy the seal 14 for removal through the passage 28. Once all of the seals have been evacuated, the valve in passageway 28 is closed and the hot plate is then secured against the top surface of the solid thermoplastic material 12 within the drum. Thereafter, the thermoplastic 1 is transferred to the desired application in a known manner through passage 26 without any possibility of exposure to moisture from any source.
Thermoplastic 12 is heated to liquefy so that 2 can be delivered.

Preferred polyisobutylene for the viscous seal 14 is
Indopol M2S from Amoco
As commercially available as O4, average molecular weight (number average molecular weight) 2,600, viscosity index 236 (^STM D 22
70). Variations thereof may include polyisobutylene mixed with a colored pigment such as titanium dioxide or carbon black to distinguish the seal 14 from the thermoplastic 12.

If a substantially lower viscosity polyisobutylene is selected, it may be more easily injected than in 236 above.
It should be noted that close viscosity indices are preferred. As the viscosity decreases, the molecular weight becomes smaller and the product carries more undesirable water. If the viscosity is too high, it will be difficult to pour the sealing material, but as mentioned above, such a seal can be heated to make it more fluid and pour properly, and it can also be heated later. Once the seal is liquefied, it can be removed.

The curable reaction product can be suitably poured to immediately seal the contents of the drum from the atmosphere, during which time it cures by reaction with the moisture in the air. When using such a seal, instead of pumping it out of the drum as described above, this reaction product can be stripped off and the hot plate is placed over the thermoplastic to be removed from the drum. be quickly lowered to In this alternative, as noted above, the peelable covering is made of a thermoplastic polymer so long as it has sufficient cohesive strength to maintain its integrity while being peeled off. It may be constructed from

Comparative testing of the seals of the present invention was conducted in drums containing moisture sensitive thermoplastics. This substance was released on January 1, 1988.
No. 07/140,851, filed May 5, 1999, which is incorporated herein by reference. This thermoplastic polymer hardens and becomes essentially thermoset when exposed to moisture. "
The "unprotected" material was sealed with a blanket of dry C02 in a conventional drum, and the drum sealed according to the invention was sealed with a 15 mm thick layer of Indopol H1900. Testing was performed on the top layer of thermoplastic in a drum at indicated time intervals using the method of ASTM 1638-74. Basically, this test measures the amount of reactive groups present in a thermoplastic. Table 1 shows the change in the number of reactive groups in thermoplastics as a function of exposure time to atmospheric moisture. These results are expressed in terms of the percentage of reactive groups present in the sample, with 100% new, unexposed material. These results showed that when this thermoplastic material is exposed to the atmosphere for a short period of about 30 minutes, all of the active atomic groups on the surface of the unprotected material react. In contrast, the material sealed according to the invention did not undergo any changes.

Table 1 Time after opening the drum Unprotected drum 0 minutes 100% 5 minutes 60% 10 minutes 13% 20 minutes 3% 30 minutes 0% Mu protected drum 100% 100% 100% 100% 100% External conditions were 25°C and 35% relative humidity.

Another test demonstrating the more practical effects resulting from the use of this invention was to test the "pumpability" of a drum of the same thermoplastic material as described above, sealed as taught herein. '' tests were conducted in comparison to similarly filled drums that had been left uncoated for 10 days. The flow rate was measured in g/min at 90° C. using the Nordson Cy bulk melter #506 described above.

The results are shown in Table 2.

Table 2 Unprotected drum Initial stage of protected drum 450 g/min 435 g/m1n
10 days later Og/min 440g
/min is a description of the preferred form and method of use of this invention, but it is possible for those skilled in the art to come up with modifications that fall within the scope of the invention as described in the claims.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a sealed drum filled with hot melt adhesive material. FIG. 2 is a vertical cross-sectional view of the drum as the hot plate moves downwardly into contact with the seal. In the figure, 10 is a container, 12 is a thermoplastic material, 14 is a seal, and 18 is a heating plate.

Claims (1)

Claims: 1. A container having side wall means and bottom wall means adapted to work with a heated platen for emptying the thermoplastic material therein during use, comprising:
A moisture or air sensitive thermoplastic material is filled with its top layer exposed and a seal is provided to protect said exposed layer of said material during storage and transportation of said container until the time of use. and the seal includes a covering incompatible with the moisture-sensitive material in the container to seal the moisture-sensitive material in the container from atmospheric moisture, the covering being overlying the exposed layer. It is viscous at room temperature when poured into
and the covering extends over the exposed layer and is in contact with the side wall means of the container, and the seal has a low water vapor permeability. 2. The container of claim 1, wherein the cover is polyisobutylene that is liquid at room temperature. 3. A container according to claim 2, wherein the cover can be on the order of 50 mm thick. 4. The container of claim 1, wherein the moisture content of the cover is less than 2 ppm. 5. The container of claim 1, wherein the cover is polyisobutylene containing a colored pigment. 6. the coating is an oligomer of polyisobutylene having an average molecular weight of 2,600 and a viscosity index of 236;
The container according to claim 1. 7. First storing a moisture or air sensitive thermoplastic in a container having side wall means and bottom wall means adapted to cooperate with a heating plate pumping means and then pumping it out of the container using said heating plate. A method for removing the above-mentioned stored material during use, the method comprising: filling the container with the above-mentioned material while momentarily exposing its top surface;
Using a wrapping material that has a low water vapor permeability and is viscous at room temperature, the wrapping material is expanded to seal the material against exposure to air and moisture during transportation and storage of the material. Pour the thermoplastic over the layer so that it is in contact with the sidewalls, sealing it against exposure to atmospheric moisture, and then move the thermoplastic through the heating plate into contact with the top layer. and removing said covering immediately before enabling pumping so that it can be removed from the container. 8. The method of claim 7, wherein the shroud is heated by the hot plate and pumped out of the container before the hot plate is moved into contact with the upper layer. 9. A container having side wall means and bottom wall means adapted to work with a heating plate for emptying the thermoplastic material therein during use, the container having a moisture or air sensitive thermoplastic material. A substance is filled with its top layer exposed and has a seal to protect said exposed layer of said substance during storage and transportation of said container until the time of use, said seal being free from moisture. and a covering that is insoluble in the moisture or air sensitive material in the container to seal it from air, the covering extending over the entire surface of the exposed layer to seal the moisture or air sensitive material in the container from the air. a thermoplastic in contact with the side wall means, the seal having a low water vapor and air permeability, and the covering being peelable from the exposed layer of the moisture or air sensitive material; A sealed container for storing substances. 10. Claim wherein the covering is a layer of thermoplastic material that is solid at room temperature and has sufficient cohesive strength to permit peeling removal from the upper layer of the moisture or air sensitive material. The sealed container according to item 9. 11. The seal of claim 9, wherein said covering is a layer of thermoset polymer having sufficient cohesive strength to permit peeling removal from said upper layer of moisture or air sensitive material. container. 12. A sealed container according to claim 10 or 11, wherein the moisture or air sensitive substance is a substance of room temperature consistency such that it must be heated with a hot plate to enable its removal. . 13. A sealed container according to claim 10 or 11, wherein the moisture or air sensitive material is a material of room temperature consistency such that it can be removed without heating. 14. The sealed container of claim 10, wherein the thermoplastic material constituting the cover is selected from the group consisting of styrene-butadiene copolymer and styrene-isoprene copolymer. 15. The sealed container according to claim 11, wherein the thermosetting polymer constituting the cover is selected from the group consisting of polyurethane, polyurea, and polysiloxane. 16. The sealed container of claim 12, wherein a separation sheet is included between the moisture or air sensitive substance and the shroud. 17. The sealed container according to claim 16, wherein the separation sheet has releasability on at least one side thereof. 18, the separation sheet is polytetrafluoroethylene,
polyethylene, aluminized polyethylene,
A material selected from the group consisting of polyester, siliconized polyester, aluminum foil, polytetrafluoroethylene coated aluminum foil, kraft paper, silicone coated kraft paper, and polytetrafluoroethylene coated kraft paper. is made,
The sealed container according to claim 17. 19. The sealed container of claim 13, wherein a separation sheet is included between the moisture or air sensitive substance and the cover. 20. The sealed container according to claim 19, wherein the separation sheet has releasability on at least one side thereof. 21, the separation sheet is polytetrafluoroethylene,
polyethylene, aluminized polyethylene,
A material selected from the group consisting of polyester, siliconized polyester, aluminum foil, polytetrafluoroethylene coated aluminum foil, kraft paper, silicone coated kraft paper, and polytetrafluoroethylene coated kraft paper. is made,
The sealed container according to claim 20.