HK1075230B

HK1075230B - Multilayered polymer based thin film structure for medical grade products

Info

Publication number: HK1075230B
Application number: HK05107507.6A
Authority: HK
Inventors: 格雷格．内布根; 基思．M．K．安德森; 迈克尔．W．沙夫
Original assignee: 巴克斯特国际公司
Priority date: 2002-03-21
Filing date: 2003-03-17
Publication date: 2011-06-17

Description

Multilayer polymer-based film structure for medical products

Cross Reference to Related Applications

This application is a continuation-in-part of U.S. patent application 09/498,674 filed on 7/2/2000; said application is a continuation of part 09/334,957 of U.S. granted patent 6,261,655 filed on 17.6.1999 and a continuation of part 08/153,602 of U.S. granted patent 5,998,019 filed on 16.11.1993, which are incorporated herein by reference and made a part hereof.

Technical Field

The present invention relates generally to polymer blends useful in the manufacture of films, and in particular to films having low deformability, which are non-adherent after steam sterilization, which are radio frequency sealable, and which are suitable for forming flexible medical containers.

Background

In the medical field, there is a need to collect, handle and store beneficial agents, in containers, transport and finally deliver them to patients by infusion through catheters for therapeutic effect, and therefore the materials used to make the containers must have unique combination of characteristics. For example, in order to be able to visually inspect a solution for particulate contaminants, the container must be optically transparent. In order to prevent air from entering the container when infusing a solution from the container by breaking the walls, the material from which the walls are constructed must be sufficiently flexible. The material must function over a wide temperature range. The material must function at low temperatures by maintaining its flexibility and toughness, as some solutions, such as certain pre-mixed drug solutions, must be stored and transported at temperatures such as-25 ℃ to-30 ℃ to minimize drug degradation. The material must also be able to withstand heat sterilization at elevated temperatures, a process that most medical packaging and nutritional products undergo prior to shipment. The sterilization process generally involves subjecting the container to steam, typically at a temperature of 121 c and an elevated pressure. Thus, there is a need for materials that can withstand temperature and pressure without significant deformation ("heat distortion resistance").

For ease of fabrication into useful goods, the ideal material should be sealable with radio frequency ("RF") of typically about 27.12 MHz. Thus, the material should have sufficient dielectric loss characteristics to convert RF energy into thermal energy. A further requirement is that the environmental impact of the articles made from the material should be minimized during the destruction of the article after a predetermined period of use. For those commodities that are to be destroyed in landfills, it is desirable to use as little material as possible and avoid the incorporation of low molecular weight leachable components for the manufacture of the product. Thus, the material should be lightweight and have good mechanical strength. Other benefits may be realized by using a material that can be recycled by thermoplastic reprocessing of the used commodity into other useful commodities.

For those containers that are destroyed by incineration, it is necessary to use a material that helps eliminate the risk of biohazards and minimizes or even completely eliminates the formation of environmentally harmful, irritating and corrosive inorganic acids or other harmful, irritating or otherwise undesirable products when incinerated.

The ideal material should also be free of or contain minimal amounts of low molecular weight additives, such as plasticizers, stabilizers, etc., which may be released into the medical or biological fluid or tissue, thereby posing a risk to the patient using the device, or contaminating materials stored or processed in the device. For containers storing infusion solutions, such contamination may enter the infusion path and enter the patient, causing the patient to become injured or die.

Conventional flexible polyvinyl chloride materials can meet many of the above requirements, and in some cases most of them. Polyvinyl chloride ("PVC") also has a distinct advantage, being the most cost-effective material that can be used to manufacture equipment that meets the above-mentioned needs. However, PVC generates hydrogen chloride upon incineration (or hydrochloric acid upon contact with water) to cause corrosion of the incinerator in an amount that is objectionable. PVC sometimes contains plasticizers and can leach into drugs or biological fluids or tissues that come into contact with the PVC formulation. Therefore, many materials have been designed to replace PVC. However, most replacement materials are too expensive to apply and still do not meet all of the above requirements.

Many attempts have been made to develop alternative membrane materials to PVC, but most have failed for some reason or other. For example, the multi-layer film compositions disclosed in U.S. patent 4,966,795, which are resistant to steam sterilization, cannot be welded by radio frequency dielectric heating and thus cannot be assembled by such rapid, low cost, reliable and practical methods. European patent application No. ep 0310143 a1 discloses a multilayer film that can meet most requirements and is RF weldable. However, the components of the disclosed films are cross-linked by radiation and thus cannot be recycled by standard thermoplastic processing methods. In addition, due to the irradiation step, a considerable amount of acetic acid is released and trapped in the material. In steam sterilization, acetic acid migrates into the package contents as a contaminant and, by altering the pH of the contents, acts as a potential chemical reactant for the contents or as a catalyst for the degradation of the contents.

U.S. patent 5,998,019, owned by the assignee of the present invention, discloses a multilayer polymeric structure that addresses many, if not all, of the aforementioned problems. However, one problem with the structure of the' 019 patent is that the internal solution contact layers of the structure either stick to each other or bond to other similar structures (e.g., other films or when formed into containers) after the autoclave sterilization process. The inner solution contact layer of the' 019 patent is an RF sealing layer or a blend of two polyolefins and a styrene and hydrocarbon block copolymer as a compatibilizer. This document discloses a specific composition of RF sealing layer, which is also disclosed in us patent 5,849,843; 5,854,347 and 5,686,527, which are owned by the present assignee and incorporated by reference.

U.S. patent 6,083,587, also owned by the present assignee, provides a multilayer structure wherein the inner solution contacting layer may be a polyolefin selected from the group consisting of homopolymers and copolymers of alpha olefins having from 2 to 20 carbon atoms. However, the' 587 patent does not disclose the inner non-solution contact layer being an RF-sealing layer or a structure comprising an RF-susceptible polymer.

The main object of the present invention is to create thermoplastic materials which are overall superior to those known to us, which have hitherto been known to the person skilled in the art or which have been used commercially or marketed. The properties of such materials include flexibility, malleability, and stress recoverability, not just at room temperature, but through a wide range of peripheral and freezing temperatures. Such materials should be sufficiently optically transparent for visual inspection and steam sterilizable at temperatures up to 121 ℃. Such materials should be able to withstand significant stresses without exhibiting stress whitening phenomena that are predictive of physical or cosmetic defects. It is a further object that the material can be assembled by RF methods.

Another object is that the material is substantially free of low molecular weight leachable additives and can be safely disposed of by incineration without generating large amounts of corrosive inorganic acids. Another object is that the material can be recycled after use by standard thermoplastic processing methods. Also, it is desirable that the material be miscible with regrind waste material recovered from the manufacturing process, thereby saving material costs and reducing manufacturing waste. Also, it is desirable that the material should not have its RF sealing layer in contact with the same layer of other films, so that the film will block itself or with other films during and after autoclave processing to a minimum. Also, the desired material should be non-oriented because the oriented film may shrink when subjected to heat treatment. Finally, this material should be a cost-effective alternative to the various PVC formulations currently used as medical devices.

When more than one polymer is mixed to form an alloy composition, it is difficult to achieve all of the above goals simultaneously. For example, in most cases, the alloy composition may scatter light; thus, they cannot satisfy the purpose of optical transparency. The light scattering intensity (as measured by haze) depends on the domain size of the component in the micrometer (μm) range, as well as the proximity of the refractive indices of the components. It is generally difficult to select components that satisfactorily handle very small domain sizes and yet have minimal refractive index deviations. Also, film structures known to date, which typically contain stearates or fatty acids in the solution contact layer, leach some of the undesirable components into the solution in contact with the film structure.

The present invention is directed to solving these and other problems.

Summary of The Invention

Specific multilayer polymer-based structures are disclosed. Such films may be formed into medical articles of commerce, such as containers for storing medical solutions or blood products, blood bags, and related items, or other products made from multilayer structures.

It is an object of the present invention to prepare a multilayer film having the following physical properties: (1) a mechanical modulus of less than 40,000psi, more preferably less than 25,000psi as measured by ASTM D-882, (2) a length that can recover 70% or more, more preferably 75% or more after an initial deformation of 20%, (3) a 9 mil thick compound having an optical haze of less than 30%, more preferably less than 15%, as measured by ASTM D-1003, (4) a loss tangent greater than 1.0, more preferably greater than 2.0, as measured at 1Hz and processing temperature, (5) a halogen content of less than 0.1%, more preferably less than 0.01%, (6) a low molecular weight water soluble component of less than 0.1%, more preferably less than 0.005%, (7) a maximum dielectric loss between 1-60MHZ and 25-250 ℃ of greater than or equal to 0.05, more preferably greater than or equal to 0.1, (8) an autoclave resistance as measured by sample creep at 121 ℃, 27psi of less than or equal to 60%, more preferably less than or equal to 20%, and (9) recording the presence or absence of stress whitening after stretching to about 100% elongation at a moderate rate of about 20 inches (50cm) per minute, resulting in no stress whitening.

The multilayer structure of the present invention has two separate skin layers, each preferably comprising a propylene-containing polymer. The structure further includes a radio frequency ("RF") sensitive layer adhered to the skin layer. The composition of the RF layer is: a polypropylene polymer as a first component, a non-polypropylene polyolefin (without propylene repeating units) as a second component, a radio frequency sensitive polymer as a third component, and a polymer compatibilizer as a fourth component. In alternative embodiments, additional layers such as cores, scrap and barrier layers may be added to the skin and RF layers to provide additional or enhanced functionality to the resulting film structure, wherein the radio frequency susceptible polymer is selected from the group consisting of polyamides, ethylene vinyl acetate with a vinyl acetate content of 18-50 wt%, ethylene methyl acrylate copolymers with a methyl acrylate content of between 20-40 wt%, ethylene vinyl alcohol with a vinyl alcohol content of 15-70%.

As stated above, the RF layer is U.S. patent 5,849,843; 5,854,347 and 5,686,527, both of which are incorporated herein by reference and made a part hereof. The multilayer film structure of the present invention has additional features not found in the RF layer composition alone. Additional features of the multilayer film include a bright outer surface, and reduced adhesion to the outer surface of the film structure. In addition, the multilayer film structure has improved vapor barrier properties, higher strength and optical clarity, and a reduced tendency to be cleaner or migrate into the container contents. Finally, the internal solution contact layer of the present invention minimizes partial and total adhesion to itself or to other membranes after autoclaving.

The core layer interposed between the skin layer and the RF layer is composed of three components. Preferably, the first component is polypropylene constituting 40% of the core layer, the second component is ultra low density polyethylene ("ULDPE") constituting 50% by weight of the core layer, and the third component is a styrene-hydrocarbon block copolymer constituting 10% by weight of the core layer, more preferably a SEBS block copolymer. The entire core layer was about 4.0 mils thick.

Also, for economic or other reasons, it is desirable to incorporate reground waste materials recovered during processing of membrane materials into membrane structure compositions. This can result in the use of large amounts of scrap as a weight percentage of the total layer structure, thereby substantially reducing the cost of the film product. The regrind scrap may be incorporated into the structure as an additional dispersed layer somewhere between the skin and RF layers, or may be blended into the core layer as additional components. In either case, significant resources can be saved by reprocessing the scrap.

In order to increase the gas barrier properties of the structure, it is desirable to incorporate a barrier layer between the surface layer and the RF layer. The barrier layer may be bonded to the peripheral layer using an adhesive tie layer. The barrier layer may be chosen from ethylene-vinyl alcohols such as scalar, under the trade name Evalca (Evalca corporation)(DuPont chemical company) polyamides of high glass or crystalline form, such as those sold by British oil under the trade nameHigh nitrile content acrylonitrile copolymers.

Films having the structure and composition described above have been found to be flexible, optically clear, stress-free, whitened, and steam and radiation sterilizable. In addition, such films are suitable for medical use because the components that make up the film have minimal extractability to fluids and substances that come into contact with the composition. Further, since the film does not produce harmful degradation products in incineration, it does not exert an influence on the environment. Finally, the film provides a cost-effective alternative to PVC.

The invention specifically discloses:

1. a multilayer structure comprising:

a first skin layer consisting essentially of a propylene-containing polymer and a styrene and hydrocarbon block copolymer;

a Radio Frequency (RF) susceptible layer adhered to the first skin layer, the RF layer having a first component of a propylene-based polymer, a second component of a non-propylene-based polyolefin, a third component of a radio frequency susceptible polymer, and a fourth component of a polymeric compatibilizer; and

a second skin layer adhered to the RF layer opposite the first skin layer, the second skin layer consisting essentially of a propylene-containing polymer and a styrene and hydrocarbon block copolymer;

the structure has the following range of physical properties:

a＜40,000psi；

b＞＝70％；

c＜30％；

d＞1.0；

e＜0.1％；

f＜0.1％；

g＞＝0.05；

h＜＝60％；

i＝0；

wherein:

a is the mechanical modulus of the composition as measured according to ASTM D-882;

b is the percent recovery of the length of the composition after 20% initial deformation;

c is the optical haze measured according to ASTM D-1003 for compositions processed to a thickness of 9 mils;

d is the loss tangent of the composition at 1Hz, measured at the melting point processing temperature;

e is the halogen content by weight of the composition;

f is a low molecular weight water soluble component of the composition;

g is the dielectric loss of the composition between 1 and 60MHZ and at a temperature of between 25 and 250 ℃;

h is the sample creep measured at 121 ℃ for a1 inch strip composition under a 27psi load; and the number of the first and second groups,

the composition showed no stress whitening when stretched at a moderate speed of 20 inches per minute to 100% elongation of 2 times the original length, with the occurrence of stress whitening indicated at 1 or the absence of stress whitening indicated at 0 being recorded.

2. A multilayer structure comprising:

a second skin layer adhered to the RF layer opposite the first skin layer, the second skin layer consisting essentially of a propylene-containing polymer and a styrene and hydrocarbon block copolymer.

3. The structure of item 2, wherein the non-propylene polyolefin of the RF layer is selected from the group consisting of ultra low density polyethylene, polybutylene, butylene ethylene copolymers, ethylene vinyl acetate copolymers with a vinyl acetate content of between 18-50%, ethylene methyl acrylate copolymers with a methyl acrylate content of between 20-40%, ethylene n-butyl acrylate copolymers with an n-butyl acrylate content of between 20-40%, ethylene acrylic acid copolymers with an acrylic acid content of greater than 15%.

4. The structure of item 2, wherein the radio frequency susceptible polymer is selected from the group consisting of polyamides, ethylene vinyl acetate with a vinyl acetate content of 18-50 wt%, ethylene methyl acrylate copolymers with a methyl acrylate content of between 20-40 wt%, ethylene vinyl alcohol with a vinyl alcohol content of 15-70%.

5. The structure of item 2, wherein the polymeric compatibilizer of the RF layer is a styrene ethylene-butylene styrene block copolymer.

6. The structure of item 5, wherein the styrene ethylene-butylene styrene block copolymer is functionalized with maleic anhydride.

7. The structure of item 2, further comprising a first non-radio frequency susceptible core layer interposed between the first skin layer and the RF layer.

8. The structure of item 7, wherein the first non-radio frequency-sensitive core layer comprises:

a first component of a polyolefin;

a second component selected from the group consisting of ultra low density polyethylene, polybutylene copolymers, and

a third component of a compatibilizer.

9. The structure of item 8, wherein the polyolefin of the first component of the first non-radio frequency susceptible core layer is polypropylene.

10. The structure of item 8, wherein the first non-radio frequency susceptible core layer second component is an ultra low density polyethylene.

11. The structure of item 8, wherein the third component of the first non-radio frequency susceptible core layer is a styrene ethylene-butylene styrene block copolymer.

12. The structure of item 8, wherein the first non-radio frequency-sensitive core layer comprises a fourth component consisting of scrap material.

13. The structure of item 8, further comprising a scrap layer interposed between the first non-radio frequency susceptible core layer and the first skin layer.

14. The structure of item 8, further comprising a scrap layer interposed between the first non-radio frequency susceptible core layer and the radio frequency susceptible layer.

15. The structure of item 8, further comprising:

a scrap layer adhered to the first non-rf susceptible core layer and opposite the first skin layer; and

a second core layer bonded to the scrap layer and opposite the first non-radio frequency susceptible core layer.

16. The structure of item 8, further comprising a barrier layer.

17. The structure of item 16, wherein the barrier layer is interposed between the first non-radio frequency susceptible core layer and the RF layer.

18. The structure of item 16, wherein the barrier layer is interposed between the first non-radio frequency susceptible core layer and the first skin layer.

19. The structure of item 8, further comprising:

a barrier layer adhered to the first non-radio frequency susceptible core layer and opposite the first skin layer; and the number of the first and second groups,

a second core layer adhered to the barrier layer and opposite the first non-radio frequency susceptible core layer.

20. The structure of item 19, further comprising two tie layers, wherein one tie layer is adhered to one edge of the barrier layer and the other tie layer is adhered to an opposite edge of the barrier layer.

21. The structure of item 16, wherein the barrier layer is selected from the group consisting of ethylene vinyl alcohol, and highly glassy, crystalline polyamides.

22. The structure of item 20, wherein the tie layer is a modified ethylene and propylene copolymer.

23. A multilayer structure comprising:

a radio frequency RF susceptible layer adhered to the first skin layer, the RF layer having a first component of a propylene based polymer in an amount ranging from 30 to 60 wt% of the RF layer, a second component of a non-propylene based polyolefin in an amount ranging from 0 to 60 wt% of the RF layer, a third component of a radio frequency susceptible polymer in an amount ranging from 3 to 40 wt% of the RF layer, and a fourth component of a polymeric compatibilizer in an amount ranging from 5 to 40 wt% of the RF layer; and

24. The structure of item 23, wherein the first component of the RF susceptible layer is polypropylene.

25. The structure of item 24, wherein the second component of the RF susceptible layer is selected from the group consisting of ultra low density polyethylene and polybutene-1.

26. The structure of item 25, wherein the third component is a fatty acid polyamide.

27. The structure of item 26, wherein the fourth component is a styrene ethylene-butylene styrene block copolymer.

28. The structure of item 27, wherein the styrene ethylene-butylene styrene block copolymer is functionalized with maleic anhydride.

29. The structure of item 28, wherein the composition of the RF layer in weight percent of the RF layer ranges as follows:

35-45% of a first component;

35-45% of a second component;

7-13% of a third component; and

and 7-13% of a fourth component.

30. The structure of item 29, wherein the fatty acid polyamide is a dimer fatty acid polyamide.

31. A multilayer structure comprising:

a core layer having one side adhered to the first skin layer;

a radio frequency, RF, susceptible layer adhered to the core layer opposite the first skin layer, the RF layer comprising: a first component of a propylene-based polymer in an amount ranging from 30 to 60 wt% of the RF layer, a second component of a non-propylene polyolefin in an amount ranging from 25 to 50 wt% of the RF layer, a third component of a radio frequency susceptible polymer in an amount ranging from 3 to 40 wt% of the RF layer, and a fourth component of a polymeric compatibilizer in an amount ranging from 5 to 40 wt% of the RF layer; and

32. The structure of item 31, wherein the core layer is non-radio frequency sensitive.

33. The structure of item 32, wherein the second component of the RF susceptible layer is selected from the group consisting of ultra low density polyethylene and polybutene-1, the radio frequency susceptible polymer is a dimer fatty acid polyamide, the fourth component of the RF susceptible layer is a SEBS block copolymer, the core layer comprises:

a first component polyolefin;

the second component is selected from ultra-low density polyethylene, and polybutylene copolymer; and

a third component compatibilizer.

34. The structure of item 33, wherein the polyolefin of the first component of the core layer is polypropylene.

35. The structure of item 34, wherein the second component of the core layer is an ultra low density polyethylene.

36. The structure of item 35, wherein the compatibilizer of the third component of the core layer is a styrene ethylene-butylene styrene block copolymer.

37. The structure of item 36, wherein the core layer further comprises a scrap material component.

38. A laminated multilayer structure comprising:

a radio frequency, RF, susceptible layer, the RF layer consisting of: a first component of a propylene-based polymer in an amount ranging from 30 to 60 wt% of the RF layer, a second component of a non-propylene polyolefin in an amount ranging from 25 to 50 wt% of the RF layer, a third component of a radio frequency susceptible polymer in an amount ranging from 3 to 40 wt% of the RF layer, and a fourth component of a polymeric compatibilizer in an amount ranging from 5 to 40 wt% of the RF layer;

a first core layer between the first skin layer and the RF layer; and the number of the first and second groups,

a scrap layer bonded to the first core layer; and

39. The structure of item 38, wherein one side of the first skin layer is bonded to the first core layer, the scrap layer is bonded to the first core layer on the opposite side of the first skin layer, and the RF-susceptible layer is bonded to the scrap layer on the opposite side of the first core layer.

40. The structure of item 38, wherein the first skin layer is bonded on one side to the scrap layer, the first core layer is bonded to the scrap layer on an opposite side of the first skin layer, and the RF susceptible layer is bonded to the first core layer on an opposite side of the scrap layer.

41. The structure of item 40, comprising a second core layer interposed between the first core layer and the RF-susceptible layer.

42. The structure of item 38, wherein the second component of the RF susceptible layer is selected from the group consisting of ultra low density polyethylene and polybutene-1, the radio frequency susceptible polymer is a dimer fatty acid polyamide, the fourth component of the RF susceptible layer is a SEBS block copolymer, the first core layer comprises:

a first component polyolefin;

a second component selected from the group consisting of ultra low density polyethylene, and polybutylene copolymers; and the number of the first and second groups,

a third component compatibilizer.

43. A multilayer structure comprising:

a radio frequency, RF, susceptible layer, the composition of said RF layer being as follows: a first component of a propylene-based polymer in an amount ranging from 30 to 60 wt% of the RF layer, a second component of a non-propylene polyolefin in an amount ranging from 25 to 50 wt% of the RF layer, a third component of a radio frequency susceptible polymer in an amount ranging from 3 to 40 wt% of the RF layer, and a fourth component of a polymeric compatibilizer in an amount ranging from 5 to 40 wt% of the RF layer;

a first core layer between the first skin layer and the RF layer;

a barrier layer bonded to the first core layer; and

44. The structure of item 43 wherein the first skin layer is bonded on one side to the barrier layer, the first core layer is bonded to the barrier layer on the opposite side of the first skin layer, and the RF-susceptible layer is bonded to the first core layer on the opposite side of the barrier layer.

45. The structure of item 43 wherein one side of the first skin layer is bonded to the first core layer, the barrier layer is bonded to the first core layer on the opposite side of the first skin layer, and the RF-susceptible layer is bonded to the barrier layer on the opposite side of the first core layer.

46. The structure of item 44, wherein the second core layer is interposed between the first core layer and the RF-susceptible layer.

47. The structure of item 43, wherein the second component of the RF susceptible layer is selected from the group consisting of ultra low density polyethylene and polybutene-1, the radio frequency susceptible polymer is a dimer fatty acid polyamide, and the fourth component of the RF susceptible layer is a SEBS block copolymer, wherein the barrier layer is selected from the group consisting of ethylene vinyl alcohol and high glassy polyamide.

48. The structure of item 43, further comprising two tie layers, wherein one tie layer is on one side of the barrier layer and the other tie layer is on the opposite side of the barrier layer.

49. The structure of item 48, wherein the tie layer is a modified copolymer of ethylene and propylene.

50. A multilayer structure comprising:

a core layer having one side adhered to the first skin layer;

a radio frequency, RF, susceptible layer adhered to the core layer opposite the first skin layer, the RF layer comprising: high melting temperature and flexible polypropylene in an amount ranging from 30 to 60 wt% of the RF layer, a radio frequency susceptible polymer in an amount ranging from 5 to 20 wt% of the RF layer, and a polymer compatibilizer in an amount ranging from 5 to 20 wt% of the RF layer; and

51. The structure of item 50, wherein the radio frequency susceptible polymer of the RF susceptible layer is a dimer fatty acid polyamide and the polymeric compatibilizer is a styrene ethylene-butylene styrene block copolymer.

52. The structure of item 51, wherein the core layer comprises:

a first component polyolefin;

a second component selected from the group consisting of ultra low density polyethylene, and polybutylene copolymers; and

a third component compatibilizer.

Other features and advantages of the present invention will be described in, and will be apparent from, the accompanying drawings and the detailed description of the presently preferred embodiments.

Brief description of the drawings:

FIG. 1 is a cross-sectional view of a three-layer film structure of the present invention;

FIG. 2 is a cross-sectional view of a three layer film structure of the present invention comprising a core layer incorporated in the film of FIG. 1;

FIG. 3 is a cross-sectional view of a four-layer structure of the present invention containing a dispersed scrap layer between the RF and core layers;

FIG. 4 is a cross-sectional view of a film structure in which a core layer is divided into two layers using regrind scrap as a dispersion layer;

FIG. 5 is a cross-sectional view of a film structure of the present invention including a barrier layer between the core layer and the RF layer;

FIG. 6 is the same structure as FIG. 5 except that the barrier layer divides the core layer into two core layers; and

fig. 7 is a container made from a film structure of the present invention.

Detailed description of the preferred embodiments

While the invention is susceptible of embodiments in many different forms, there will be described herein in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the exemplary embodiments.

According to the present invention, a multilayer film structure is provided that meets the above-mentioned needs.

Fig. 1 is a three-layer film structure 10 comprising a first skin layer 12, a second skin layer 14, and a radio frequency ("RF") susceptible layer 16. The first skin layer 12 and the second skin layer 14 have heat distortion resistance and abrasion resistance. Another benefit of the skin layers is that each layer is substantially, preferably completely, free of erucamide and stearate components, thereby reducing, preferably eliminating, leaching of these components into the solution in contact with the membrane structure. A further benefit of the second skin layer is that it improves the overall appearance of the film structure due to reduced surface staining.

The first skin layer and the second skin layer are each preferably a propylene-containing polymer. Suitable propylene-containing polymers include: polypropylene homopolymers, copolymers and terpolymers of propylene with one or more olefin comonomers containing from 2 to about 18 carbon atoms. Suitable polypropylene copolymers and terpolymers include random or block copolymers of propylene and ethylene or random or block terpolymers of propylene/ethylene/butylene. Suitable copolymers of propylene and an olefin are sold commercially by Montell corporation as PRO FAX, PRO FAX ULTRA and CATALLOY, and by Fina petrochemical company (n/k/a ATOFINA)Series of commercial products, such as Fina6671XBB, 6573XHC, 7450HC and 7602Z. The first skin layer 12 and the second skin layer 14 should have a thickness in the range of about 0.2 to 3.0 mils. Both skin layers may further comprise a second component of a copolymer of styrene and a hydrocarbon, preferably a block copolymer of styrene and a hydrocarbon, more preferably a triblock copolymer of styrene-ethylene propylene styrene SEBS available from Shell chemical company/Ripplewood Holdings LLC under the trade name KRATON^TMThe product series. More preferably, the SEBS component is KRATON^TMG-1657。

The RF susceptible layer 16 of the present invention should have a dielectric loss greater than 0.05 at frequencies in the range of 1-60MHz and at ambient temperatures in the range of 250 c. The RF layer 16 preferably has 4 components. The RF layer 16 has RF sealability, flexibility, heat distortion resistance, and compatibility with the film structure 10. The first component of the RF layer 16 is selected from polypropylene copolymers, preferably random copolymers of propylene alpha-olefins ("PPEs"). PPE's had the desired rigidity and resistance at an autoclave temperature of 121 ℃. However, PPE's are too rigid to meet the flexibility requirements. By alloying in certain low modulus polymers, better flexibility can be achieved.

These low modulus copolymers may include ethylene-based copolymers such as ethylene-vinyl acetate copolymers ("EVA"), ethylene-alpha olefin copolymers, or so-called ultra low density (typically less than 0.90Kg/L) polyethylene ("ULDPE"). These ULDPEs include the product name A485(Mitsui petrochemical company) with the product name 4023-4024(Exxon chemical Co.), andtechnical polymers (dow chemical company) and the like are commercially available products. Additionally, polybutene-1 ("PB"), such as the products sold by Shell chemical company under the designation PB-8010, PB-8310; thermoplasticized elastomers (Shell chemical company) based on SEBS block copolymers, polyisobutylene ("PIB") under the product names Vistanex L-80, L-100, L-120, L-140(Exxon chemical company), ethylene alkyl acrylates, such as methyl acrylate copolymers ("EMA") under the product names EMAC2707 and DS-1130(Chevron), and n-butyl acrylate ("ENBA") (Quantum chemical) are suitable copolymers for use. Ethylene copolymers such as acrylic and methacrylic acid copolymers and partially neutralized salts thereof and ionomers, e.g.(Dow chemical Co.) and(E.I.DuPont de Nemours&company) are also suitable for use. Typically, ethylene-based copolymers having melting points below 110 ℃ are not suitable for autoclaving applications at 121 ℃. Moreover, the flexibility and autoclaving requirements of each component can only be met within a limited range of proportions.

Preferred first components are selected from the group consisting of homopolymeric and random copolymers of polypropylene with alpha-olefins. The first component constitutes about 30-60%, more preferably 35-45%, and most preferably 45% by weight of the RF layer. For example, one preferred first component comprises a random copolymer of propylene and ethylene wherein the propylene content is in the range of 0 to 6% by weight of the copolymer, more preferably 2% to about 6%.

The second component of the RF layer 16 imparts flexibility and low temperature ductility to the RF layer 16, and is selected from the group consisting of: polyolefins free of propylene repeating units ("non-propylene based polyolefins") include ethylene copolymers including ULDPE, polybutene, butene ethylene copolymers, ethylene vinyl acetate copolymers with a vinyl acetate content of between about 18-50%, ethylene methyl acrylate copolymers with a methyl acrylate content of between about 20-40%, ethylene n-butyl acrylate with a n-butyl acrylate content of between 20-40%, ethylene acrylic acid copolymers with an acrylic acid content of greater than about 15%. An example of these products is sold under the product names Tafmer A-4085(Mitsui), EMAC DS-1130(Chevron), Exact 4023, 4024 and 4028 (Exxon). Preferably, the second component may be an ULPDE sold by Mitsui petrochemicals under the product name TAFMER A-4085 or polybutene-1 PB8010 and PB8310 (Shell chemical) and should constitute about 25-50%, more preferably 35-45%, most preferably 45% by weight of the film.

The first and second components of the RF layer 16 may be replaced by a single component selected from the group consisting of: high melting temperature and flexible olefins such as polypropylene sold by Rexene company under the product name FPO. The melting temperature of this component should be above 130 ℃ and the modulus below 20,000 psi. This component should constitute between 30-60% by weight of the RF layer.

In order to obtain RF dielectric loss of the RF layer 16, a specific known high dielectric loss component is included as a third component in the film structure 10. For example, EVA and EMA with sufficiently high comonomer content exhibit effective loss characteristics at 27MHz such that the composition can be sealed by dielectric processes. Polyamides, a class of materials, and ethylene vinyl alcohol ("EVOH") copolymers (typically produced by hydrolysis of EVA copolymers), both have high dielectric loss characteristics at suitable temperatures. Other active materials include PVC, vinylidene chloride and fluoride, anda copolymer of bis-phenol a and epichlorohydrin sold by Union Carbide. However, these chlorine and fluorine-containing polymers are contained in such an effective amount that they generate inorganic acids upon incineration to thereby adversely affect the environment. Thus, the third component of the RF layer 16 is preferably selected from polyamides.

Preferably, the polyamide according to the invention can be chosen from aliphatic polyamides obtained by condensation of diamines containing from 2 to 13 carbon atoms, aliphatic polyamides obtained by condensation of diacids containing from 2 to 13 carbon atoms, polyamides obtained by condensation of dimer fatty acids, and amide-containing copolymers (random, block or graft).

Polyamides such as nylon are widely used in film materials because they impart abrasion resistance to the film. However, nylon is rarely found in the layer in contact with the medical solution because they typically contaminate the solution in the form of leaching into the solution. However, the applicants of the present invention have found that many of the dimer fatty acid polyamides sold, for example, by Henkel under the names MACROMELT and VERSAMID, do not cause such contamination and are therefore the most preferred third component of the RF layer 16. The third component should constitute about 3-40%, more preferably between 7-13%, and most preferably 10% by weight of the RF layer 16.

The fourth component of the RF layer 16 imparts compatibility between the polar and non-polar components of the RF layer 16. The fourth component is selected from styrene-hydrocarbon block copolymers and is preferably an SEBS block copolymer modified with maleic anhydride, epoxy or carboxylate functionality, the most preferred fourth component being an SEBS block copolymer functionalized with maleic anhydride. One such product is sold under the name KRATON by Shell chemical company/Ripplewood Holdings LLC^TMRP-6509. The fourth component should constitute about 5-40%, more preferably 7-13%, and most preferably 10% by weight of the RF layer 16.

Likewise, it is worth including in the RF layer 16 as a fifth component an SEBS block copolymer that is not modified by the functional groups described above, such as sold by Shell chemical company/RipplewoodHolding LLC under the name KRATON^TMA product of G-1652. Such components should constitute 5-40%, more preferably between 7-13%, and most preferably 10% by weight of the RF layer 16.

The preferred thickness of the RF susceptible layer 16 is in the range of 1-15 mils, more preferably 5.0-8.0 mils, and most preferably 6.0 mils. The skin layer thickness is in the range of 0.2-3.0 mils, most preferably 0.5 mils.

Fig. 2 is another embodiment of the present invention comprising a non-radio frequency susceptible core layer 18 interposed between the first skin layer 12 and the RF layer 16. The core layer 18 imparts heat distortion resistance and flexibility to the film structure 10, as well as compatibility between the components of the film structure 10. Preferably, the core layer has a thickness in the range of 0.5-10 mils, more preferably 1-4 mils. The core layer 18 includes three components. The first component is a polyolefin, preferably polypropylene in an amount of about 20 to 60 percent by weight of the core layer 18, more preferably 35 to 50 percent, and most preferably 45 percent of the core layer 18.

The second component of the core layer 18 is selected from compounds that impart flexibility to the core layer 18, including ULDPE, polybutylene copolymers. Preferably, the second component of the core layer is ULDPE or polybutene-1 in an amount of about 40 to 60% by weight, more preferably about 40 to 50% by weight, and most preferably 40% by weight.

The third component of the core layer 18 is selected from a group of compounds that impart compatibility between the components of the core layer 18, including styrene-hydrocarbon block copolymers and most preferably SEBS block copolymers. The third component is preferably present in an amount of about 5 to 40%, more preferably about 7 to 15%, and most preferably 15% by weight of the core layer 18.

A fourth component may also be added to the core layer 18, reground scrap seal material recovered from container manufacture. The scrap is scattered throughout the core layer 18. The scrap material may be added in the preferred amount of about 0-50% by weight of the core layer 18, more preferably in the range of about 10-30%, and most preferably in the range of about 3-12%. Any predetermined number of core layers (e.g., second core layers) inserted in a multilayer film structure are also contemplated by the present invention.

Fig. 3 is another embodiment of a multilayer film structure having a first skin layer 12, a second skin layer 14, an RF layer 16, and a core layer 18 as described above, and an additional scrap dispersion layer 20 between the core layer 18 and the RF layer 16. Another embodiment (not shown) places the scrap layer 20 between the first skin layer 12 and the core layer 18. Fig. 4 shows scrap layer 20 separating core layer 16 into first and second core layers 18a and 18 b. Preferably, the regrind layer thickness should be in the range of 0.5-5.0 mils, and most preferably 1.0 mil.

Fig. 5 is another embodiment of the present invention having 5 layers comprising the first skin layer 12, the second skin layer 14, the RF layer 16 and the core layer 18 described above, and the barrier layer 22 interposed between the core layer 18 and the RF layer 16. In another embodiment (not shown), the barrier layer 22 is interposed between the first skin layer 12 and the core layer 18. In yet another embodiment (not shown), the barrier layer 22 separates the core layer 18 into a first core layer 18a and a second core layer 18 b. As shown in fig. 6, the present invention also provides a barrier layer 22 interposed between two opposing tie layers (opposing tie layers)24a and 24b, which are further interposed between the first and second core layers 18a and 18 b.

The barrier layer 22 increases the gas barrier properties of the membrane structure 10. Barrier layer 22Selected from the following: such as ethylene vinyl alcohol under the trade name Evalca (Evalca corporation), such as scalarHigh vitreous or high crystalline polyamides of DuPont chemical company, high nitrile content acrylonitrile copolymers, for example those sold by British oil companyPreferably, the barrier layer 22 is ethylene vinyl alcohol and has a thickness in the range of 0.3 to 1.5 mils, most preferably 1.0 mil. The tie layer 24 may be selected from modified ethylene and propylene copolymers such as those marketed under the names Prexar (Quantum chemical) and Bynel (dupont) and should have a thickness in the range of 0.2-1.0 mils, most preferably 0.5 mils.

The layers may be processed by coextrusion, extrusion coating, or other applicable processes. These materials may be used to make an i.v. medical kit, such as the one shown in fig. 7, generally designated 50.

Example (b):

it is to be understood that the invention is not limited to the specific embodiments described herein. The examples in table 1 are intended to describe specific embodiments and are not intended to be limiting.

Table 1:

the above examples, as well as other embodiments of the invention, have been developed which have the following characteristics, as determined by experimental details in U.S. patent 6,261,655, which is published by the present inventors and incorporated by reference:

a) a mechanical modulus of less than 40,000psi as determined according to ASTM D-822;

b) a percent length recovery greater than or equal to about 70% after the initial 20% deformation;

c) when the composition is processed into a 9 mil film, the optical haze is less than about 30%, preferably less than 20%, as measured according to ASTM D-1003;

d) a loss tangent greater than about 1.0 measured at 1Hz and a melting point processing temperature;

e) a halogen element content of less than about 0.1% by weight;

f) less than about 0.1% of low molecular weight water soluble components;

g) a dielectric loss of the composition of greater than or equal to 0.05 measured at a temperature of from 25 ℃ to 250 ℃ at a temperature of from 1 MHz to 60 MHz;

h) testing a1 inch strip at 121 ℃ under 27psi load for 1 hour to obtain a sample creep of less than or equal to about 60%, and;

i) after being pulled tight to about 100% elongation (2 times the original length) at a moderate rate of about 20 inches (50cm) per minute, there was no stress whitening.

It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.

Claims

1. A multilayer structure comprising:

the structure has the following range of physical properties:

a＜40,000psi；

b＞＝70％；

c＜30％；

d＞1.0；

e＜0.1％；

f＜0.1％；

g＞＝0.05；

h＜＝60％；

i＝0；

wherein:

e is the halogen content by weight of the composition;

f is a low molecular weight water soluble component of the composition;

2. A multilayer structure comprising:

3. The structure of claim 2 wherein the non-propylene polyolefin of the RF layer is selected from the group consisting of ultra low density polyethylene, polybutylene, butylene ethylene copolymers, ethylene vinyl acetate copolymers with a vinyl acetate content of between 18-50%, ethylene methyl acrylate copolymers with a methyl acrylate content of between 20-40%, ethylene n-butyl acrylate copolymers with an n-butyl acrylate content of between 20-40%, ethylene acrylic acid copolymers with an acrylic acid content of greater than 15%.

4. The structure of claim 2 wherein the radio frequency susceptible polymer is selected from the group consisting of polyamides, ethylene vinyl acetate with a vinyl acetate content of 18 to 50 wt%, ethylene methyl acrylate copolymers with a methyl acrylate content of between 20% and 40 wt%, ethylene vinyl alcohol with a vinyl alcohol content of 15% to 70%.

5. The structure of claim 2, wherein the polymeric compatibilizer of the RF layer is a styrene ethylene-butylene styrene block copolymer.

6. The structure of claim 5 wherein the styrene ethylene-butylene styrene block copolymer is functionalized with maleic anhydride.

7. The structure of claim 2 further comprising a first non-radio frequency susceptible core layer interposed between the first skin layer and the RF layer.

8. The structure of claim 7 wherein the first non-radio frequency susceptible core layer comprises:

a first component of a polyolefin;

a third component of a compatibilizer.

9. The structure of claim 8 wherein the polyolefin of the first component of the first non-radio frequency susceptible core layer is polypropylene.

10. The structure of claim 8 wherein the second component of the first non-radio frequency susceptible core layer is ultra low density polyethylene.

11. The structure of claim 8 wherein the third component of the first non-radio frequency susceptible core layer is a styrene ethylene-butylene styrene block copolymer.

12. The structure of claim 8 wherein the first non-radio frequency susceptible core layer includes a fourth component comprised of scrap material.

13. The structure of claim 8 further comprising a scrap layer interposed between the first non-radio frequency susceptible core layer and the first skin layer.

14. The structure of claim 8 further comprising a scrap layer interposed between the first non-radio frequency susceptible core layer and the radio frequency susceptible layer.

15. The structure of claim 8, further comprising:

16. The structure of claim 8 further comprising a barrier layer.

17. The structure of claim 16 wherein the barrier layer is interposed between the first non-radio frequency susceptible core layer and the RF layer.

18. The structure of claim 16 wherein the barrier layer is interposed between the first non-radio frequency susceptible core layer and the first skin layer.

19. The structure of claim 8, further comprising:

20. The structure of claim 19 further comprising two tie layers, wherein one tie layer is adhered to one edge of the barrier layer and the other tie layer is adhered to an opposite edge of the barrier layer.

21. The structure of claim 16 wherein the barrier layer is selected from the group consisting of ethylene vinyl alcohol, and highly glassy, crystalline polyamides.

22. The structure of claim 20 wherein the tie layer is a modified ethylene and propylene copolymer.

23. A multilayer structure comprising:

24. The structure of claim 23 wherein the first component of the RF susceptible layer is polypropylene.

25. The structure of claim 24 wherein the second component of the RF susceptible layer is selected from the group consisting of ultra low density polyethylene and polybutene-1.

26. The structure of claim 25, wherein the third component is a fatty acid polyamide.

27. The structure of claim 26 wherein the fourth component is a styrene ethylene-butylene styrene block copolymer.

28. The structure of claim 27, wherein the styrene ethylene-butylene styrene block copolymer is functionalized with maleic anhydride.

29. The structure of claim 28 wherein the composition of the RF layer is in the following range in weight percent of the RF layer:

35-45% of a first component;

35-45% of a second component;

7-13% of a third component; and

and 7-13% of a fourth component.

30. The structure of claim 29, wherein the fatty acid polyamide is a dimer fatty acid polyamide.

31. A multilayer structure comprising:

a core layer having one side adhered to the first skin layer;

32. The structure of claim 31 wherein the core layer is non-radio frequency susceptible.

33. The structure of claim 32 wherein the second component of the RF susceptible layer is selected from the group consisting of ultra low density polyethylene and polybutene-1, the radio frequency susceptible polymer is a dimer fatty acid polyamide, the fourth component of the RF susceptible layer is a SEBS block copolymer, and the core layer comprises:

a first component polyolefin;

a third component compatibilizer.

34. The structure of claim 33 wherein the polyolefin of the first component of the core layer is polypropylene.

35. The structure of claim 34 wherein the second component of the core layer is an ultra low density polyethylene.

36. The structure of claim 35 wherein the compatibilizer for the third component of the core layer is a styrene ethylene-butylene styrene block copolymer.

37. The structure of claim 36 wherein the core layer further comprises a scrap component.

38. A laminated multilayer structure comprising:

a scrap layer bonded to the first core layer; and

39. The structure of claim 38 wherein one side of the first skin layer is bonded to the first core layer, the scrap layer is bonded to the first core layer on the opposite side of the first skin layer, and the RF susceptible layer is bonded to the scrap layer on the opposite side of the first core layer.

40. The structure of claim 38 wherein one side of the first skin layer is bonded to the scrap layer, the first core layer is bonded to the scrap layer on the opposite side of the first skin layer, and the RF susceptible layer is bonded to the first core layer on the opposite side of the scrap layer.

41. The structure of claim 40 comprising a second core layer interposed between the first core layer and the RF-susceptible layer.

42. The structure of claim 38 wherein the second component of the RF susceptible layer is selected from the group consisting of ultra low density polyethylene and polybutene-1, the radio frequency susceptible polymer is a dimer fatty acid polyamide, the fourth component of the RF susceptible layer is a SEBS block copolymer, and the first core layer comprises:

a first component polyolefin;

a third component compatibilizer.

43. A multilayer structure comprising:

a first core layer between the first skin layer and the RF layer;

a barrier layer bonded to the first core layer; and

44. The structure of claim 43 wherein one side of the first skin layer is bonded to the barrier layer, the first core layer is bonded to the barrier layer on the opposite side of the first skin layer, and the RF-responsive layer is bonded to the first core layer on the opposite side of the barrier layer.

45. The structure of claim 43 wherein one side of the first skin layer is bonded to the first core layer, the barrier layer is bonded to the first core layer on the opposite side of the first skin layer, and the RF-responsive layer is bonded to the barrier layer on the opposite side of the first core layer.

46. The structure of claim 44 wherein the second core layer is interposed between the first core layer and the RF-susceptible layer.

47. The structure of claim 43 wherein the second component of the RF susceptible layer is selected from the group consisting of ultra low density polyethylene and polybutene-1, the radio frequency susceptible polymer is a dimer fatty acid polyamide, and the fourth component of the RF susceptible layer is a SEBS block copolymer wherein the barrier layer is selected from the group consisting of ethylene vinyl alcohol and high glassy polyamide.

48. The structure of claim 43 further comprising two tie layers, wherein one tie layer is on one side of the barrier layer and the other tie layer is on the opposite side of the barrier layer.

49. The structure of claim 48 wherein the tie layer is a modified copolymer of ethylene and propylene.

50. A multilayer structure comprising:

a core layer having one side adhered to the first skin layer;

51. The structure of claim 50 wherein the radio frequency susceptible polymer of the RF susceptible layer is a dimer fatty acid polyamide and the polymeric compatibilizer is a styrene ethylene-butylene styrene block copolymer.

52. The structure of claim 51 wherein the core layer comprises:

a first component polyolefin;

a third component compatibilizer.