GB2141723A - Polyester container - Google Patents

Abstract

A translucent or transparent, flexible composition comprising a mixture of (a) from 20 to 60 weight percent of a flexible block copolymer of covalently bonded polybutylene terephthalate units and poly(1,4-butylene) oxide units, and (b) from 40 to 80 weight percent of a flexible copolyester of cyclohexane dimethanol units, and alkylene glycol units. r

Description

SPECIFICATION Polyester container Technical Field and Prior Art Various medical solutions, blood, and other products are packaged in flexible, collapsible containers, for example parenteral solutions.

Also, as stated, blood and blood components are stored in blood bags which may be made of plasticized polyvinyl chloride plastic or alternatively other formulations. For example, in Gajewski et al. U.S. Patent No. 4,300,559 a polyester blood bag is disclosed. The specific polyester material used may be in accordance with the teachings of Fagerburg U.S. Patent No. 4,045,431 which discloses polyesters which are the reaction product of cyclic diacids and cyclic diols.

Such a polyester material provides a transparent or translucent flexible container which can be collapsed.

It has been found to be desirable to use polyvinyl chloride tubing in conjunction with blood bags and other collapsible containers, and a disadvantage arises with the above polyester in that it does not easily seal with polyvinyl chloride plastic. It would be desirable to provide a container where the polyvinyl chloride tubing communicating with its access port can be easily and simply sealed to it without need for an extra technique, for example, a connector member similar to that shown in Kwong et al. U.S. Patent No.

4,327,726.

Furthermore, it would be desirable to provide a container which can be easily blow molded in which the material of which the container is made is soft and easily collapsible, to be manufactured with a relatively simple blow molding technique, so as to avoid the necessity of more sophisticated designs that are necessary for relatively stiff plastics such as polypropylene, for example, as shown in Martinet al. U.S. Patent No. 4,232,721, among others.

In accordance with this invention, a translucent, flexible, collapsible container is provided, being made of a material which has significantly improved properties to provide collapsible containers having a new combination of advantages providing an advance over the collapsible containers of the prior art. The material is preferably transparent.

First, compared with the conventional polyvinyl chloride plastic containers, the containers of this invention require no plasticizer such as di-2-ethylhexylphthalate. Likewise, the collapsible containers of this invention exhibit greater strength and flexibility at freezing temperatures of - 80"C. than comparable polyvinyl chloride plastic bags, but are substantially as soft as good polyvinyl chloride formulations at room temperature so that a simple design of bag can be used to get good flat collapse.

Additionally, unlike the polyester formulations taught in the cited U.S. Patent No.

4,045,431, the collapsible container of this invention is easily solvent bondable (with cyicohexanone, for example) to polyvinyl chloride plastic tubing to provide a strong, rigid seal.

Likewise in a blow molding operation the material used in this invention is quite forgiving and tolerant, permitting a relatively easy blow molding protocol, while having improved melt strength during the blow molding operation. The ends of the blow molded container may be sealed, and an access port may be integrally formed as part of the blow molding operation to which polyvinyl chloride tubing can be later solvent sealed.

As the result of this, the container of this invention may be prepared by blow molding at reduced cost compared with other flexible, collapsible blow molded containers, being of simple, economical design and having many properties equal to or better than polyvinyl chloride plastics.

Furthermore, the material of this invention may be subjected to autoclaving temperatures for sterilizing (about 120"C.) so that the container is acceptable for use in the health care industry.

Description of the Invention In this invention a translucent, flexible, collapsible container is provided defining at least one access port. The container is made of a material comprising a mixture of: (a) from 20 to 60 weight percent of a flexible block copolymer of covalently bonded polybutylene terephthalate units and poly(1 ,4- butylene) oxide units; and (b) from 40 to 80 weight percent of a flexible copolyester of cyclohexane dicarboxylate units, cyclohexane dimethanol units and polyalkylene glycol units.

It may be desirable for a minor amount of dimer acid units, as described in Fagerburg U.S. Patent No. 4,045,431 to be present along with the cyclohexane dicarboxylate units. Specifically, 1 ,4-cyclohexanediboxylic acid and 1 ,4-cyclohexane dimethanol are used to make the corresponding units in the polyester formulation preferred in this invention.

It is generally preferable for 25 to 35 weight percent of ingredient (a) to be present, with the balance being ingredient (b), although it is contemplated that minor amounts of other additives may be present. Ingredient (a) is commercially available, for example, from the E. l. Dupont deNemours 8 Co. under the tradename HYTREL. Ingredient (b) is available from the Eastman Kodak Company under the trademark PCCE.

The polyalkylene glycol units called for may be selected from the group consisting of ethylene glycol and propylene glycol units, although, if desired, glycol units containing higher numbers of carbon atoms may also be utilized.

As stated, the container of this invention is readily solvent sealable to polyvinyl chloride, so that polyvinyl chloride plastic tubing may be solvent sealed in communication with the access port in a manner which is greatly facilitated over a bag which is made substantially entirely of a copolyester of ingredient (b), for example.

Description of the Drawings In the drawings, Figure. 1 is an elevational view of a transparent, flexible, collapsible container in accordance with this invention having a length of polyvinyl chloride plastic tubing sealed in communicating relation with its interior as part of a multiple bag system, shown schematically.

Figure. 2 is an elevational view of the container of Fig. 1, rotated 90 degrees about its longitudinal axis, with the attached tubing not shown.

Description of Specific Embodiment Referring to the drawings, container 10 may be prepared by a conventional blow molding process from a hot, softened parison of a mixture of plastic material consisting of 30 percent by weight of HYTREL 4056 and 70 percent by weight of PCEE 9967 intimately mixed in a conventional screw extruder and formed into the parison also with conventional equipment. Container 10 can be seen to be sealed at its respective ends 12, 14 so that no closure or insert is required for sealing of the parison to form a sealed container.

Furthermore, at top end 14 one or more access ports 1 6 may be provided, being formed as an integral part of container 10 as part of the blow molding process.

If desired, a conventional form, fill, and seal operation may be utilized so that the blow molded container is filled with liquid as it is formed from the parison.

After the blow molded container 10 has been expelled from the blow mold, it may be connected to a length of polyvinyl chloride plastic tubing 18 by the simple and conventional expedient of solvent bonding using cyclohexanone or another suitable solvent. Tubing 1 8 may connect to a donor needle or a spike for access to another bag or set, or, alternatively, it may be part of a multiple bag system with tubing 1 8 communicating with the remainder of the multiple bag system which, except for the modification suggested herein, may be similar to commercially available multiple bag systems for blood collection and the like.

Alternatively, containers may be made by extruding the material of this invention into sheets and then heat sealing the sheets together in accordance with conventional technology for the manufacture of blood and parenteral solution bags.

Specifically, container 10 as shown herein may have a capacity of 250 to 300 ml. for receiving plasma from the remainder of a multiple bag system which may include containers 20, 22 interconnected by tubing 24.

As stated above, these bdgs may be made of polyvinyl chloride plastic or the like and may be used in conventional manner to collect blood in bag 20 and after centrifugation to expel blood components to bag 22 and the plasma to bag 1 0.

After collection of the plasma into bag or container 10, tubing 1 8 may be heat sealed and aevered in conventional manner, separating container 10 from the rest of the multiple bag system for freezing. As stated above, container 10 exhibits improved durability under - 80"C. temperatures than polyvinyl chloride plastic.

When it is desired to remove the slug of frozen plasma, the top portion 26 of container 10 may be removed by cutting in a manner similar to that disclosed, for example, in Bacehowski et al. U.S. Patent No. 4,253,458, which shows a frozen plasma collection system utilizing a multiple blood bag system.

Accordingly, through the use of the flexible, collapsible container of this invention, improvements in economy and effectiveness of operation are obtained, particularly for collapsible containers which bond well to vinyl tubing but at the same time withstand temperatures on the order of - 80"C. for frozen storage of blood components and the like.

The containers of this invention are also usable for other purposes, particularly for the storage of medical liquids and the like.

The above has been offered for illustrative purposes only and is not intended to limit the scope of the invention of this application, which is as described in the claims below.

Claims (7)

1. A translucent or transparent, flexible composition comprising a mixture of (a) from 20 to 60 weight percent of a flexible block copolymer of covalently bonded polybutylene terephthalate units and poly(1 ,4- butylene) oxide units, and (b) from 40 to 80 weight percent of a flexible copolyester of cyclohexane dicarboxylate units, cyclohexane dimethanol units, and polyaklylene glycol units.

2. A composition according to Claim 1, in which said polyalkylene glycol units contain polymerized units selected from ethylene glycol and propylene glycol units.

3. A composition according to Claim 1 or 2, in which from 25 to 35 weight percent of ingredient (a) is present, the balance being ingredient (b).

4. A composition according to Claim 1 or 2, wherein 20 to 35 weight percent of ingredient (a) is present and 65 to 75 weight percent of ingredient (b) is present.

5. A translucent or transparent flexible, collapsible container having at least one access port and being made from the composition of any preceding claim.

6. A container according to Claim 5, in which polyvinyl chloride plastic tubing is sealed in communication with said access port.

7. A translucent or transparent flexible, collapsible container constructed substantially as herein described with reference to the accompanying drawings and being made from a composition according to any one of Claims 1 to 4.