A polyethylene film resistant to steam sterilization and its processing technology and sterilized breathing bag

Abstract

The present application relates to the technical field of sterilized breathing bags, and specifically discloses a polyethylene film resistant to steam sterilization, its processing technology and a sterilized breathing bag. The polyethylene film includes an inner layer, an intermediate layer and an outer layer arranged in sequence, the intermediate layer is mainly made of medium melt index polyethylene; the inner layer is mainly made of medium melt index polyethylene and low melt index polyethylene; the outer layer is mainly made of medium melt index polyethylene and low melt index polyethylene; the melt index of the medium melt index polyethylene is 0.5-1.5g / 10min; the melt index of the low melt index polyethylene is 0.02-0.1g / 10min. The polyethylene film has no adhesion and deformation after being sterilized for 30 minutes at a steam temperature of 121°C, and exhibits excellent resistance to steam sterilization. Moreover, the tensile strength of the polyethylene film is ≥30Mpa and the heat sealing strength is ≥20N / 15mm, so that the polyethylene film exhibits better mechanical properties.

Description

Technical Field

[0001] The present application relates to the technical field of sterile breathing bags, and more specifically, to a polyethylene film resistant to steam sterilization and a processing technology thereof, and a sterile breathing bag. Background Art

[0002] In the pharmaceutical industry, in order to maintain a sterile state, it is inevitable to package and sterilize items. For example, rubber plugs, aluminum caps, filter elements, sealing rings, needles, silicone tubes, medical devices, etc. At this time, the items to be sterilized are often placed in a breathing bag for sealing, and then the items to be sterilized and the breathing bag are sterilized together.

[0003] The breathing bag generally includes polyethylene film and Tyvek paper, and the polyethylene film and Tyvek paper form a bag-like structure. Tyvek paper allows steam or sterilizing agents to enter and exit, but bacteria cannot pass through. When sterilization is to be carried out, the steam or sterilizing agent enters the breathing bag to kill the microorganisms and form a sterile state. Polyethylene film is a thermoplastic resin with the advantages of high insulation, high chemical stability, low water absorption, and high corrosion resistance, which can keep the breathing bag stable. The applicant found that when using breathing bags for high-temperature steam sterilization, the polyethylene film was prone to deformation when the steam temperature was 121°C and the sterilization treatment lasted for 30 minutes. Summary of the invention

[0004] In order to improve the high temperature resistance of polyethylene film and meet the requirements of high temperature steam sterilization, the present application provides a polyethylene film resistant to steam sterilization and a processing technology thereof and a sterilized breathing bag.

[0005] In a first aspect, the present application provides a polyethylene film resistant to steam sterilization, using the following technical solution:

[0006] A polyethylene film resistant to steam sterilization, comprising an inner layer, an intermediate layer and an outer layer arranged in sequence, wherein the intermediate layer is mainly made of medium melt index polyethylene;

[0007] The inner layer is mainly made of medium melt index polyethylene and low melt index polyethylene, and the weight ratio of the medium melt index polyethylene to the low melt index polyethylene is 10:(1-4);

[0008] The outer layer is mainly made of medium melt index polyethylene and low melt index polyethylene, and the weight ratio of the medium melt index polyethylene to the low melt index polyethylene is 10:(1-4);

[0009] The melt index of the medium melt index polyethylene is 0.5-1.5 g / 10 min; the melt index of the low melt index polyethylene is 0.02-0.1 g / 10 min.

[0010] The polyethylene film obtained by adopting the above technical solution has no adhesion and deformation after being sterilized for 30 minutes at a steam temperature of 121°C, showing excellent high temperature resistance and resistance to steam sterilization, meeting the requirements of high temperature steam sterilization. At the same time, the tensile strength is ≥30Mpa and the heat sealing strength is ≥20N / 15mm, so that the polyethylene film has higher tensile strength, elongation at break and heat sealing strength, showing better comprehensive performance.

[0011] Optionally, the medium melt index polyethylene is mainly composed of high-density polyethylene and metallocene polyethylene, and the weight ratio of high-density polyethylene to metallocene polyethylene is (6-8):(2-4);

[0012] The low melt index polyethylene is mainly composed of metallocene polyethylene.

[0013] Optionally, the density of the high-density polyethylene is 0.941-0.965 g / cm 3 The density of the metallocene polyethylene is 0.925-0.950 g / cm 3 .

[0014] By adopting the above technical scheme, high-density polyethylene and metallocene polyethylene have excellent processability, which not only increases the steam sterilization resistance of the polyethylene film, but also greatly improves the tensile strength and heat-sealing strength of the polyethylene film, thereby improving the mechanical properties of the polyethylene film.

[0015] In one embodiment, the melt index of high-density polyethylene is 0.99 g / 10 min, and the melt index of metallocene polyethylene is 1.20 g / 10 min. The melt index of high-density polyethylene can also be adjusted to 0.5 g / 10 min, 1.2 g / 10 min, 1.5 g / 10 min, and the melt index of metallocene polyethylene can be adjusted to 0.5 g / 10 min, 1.2 g / 10 min, 1.5 g / 10 min, etc. as needed. The melt index of high-density polyethylene is between 0.5-1.5 g / 10 min, and the melt index of metallocene polyethylene is between 0.5-1.5 g / 10 min, which can achieve the above effect.

[0016] Optionally, the melt index is obtained by ISO1133 testing.

[0017] Optionally, the thickness of the middle layer is 0.02-0.05 mm, the thickness of the inner layer is 0.02-0.05 mm, and the thickness of the outer layer is 0.02-0.05 mm.

[0018] By adopting the above technical solution, the thickness of the inner layer, the middle layer and the outer layer are optimized, which facilitates the processing of the polyethylene film.

[0019] Optionally, the raw material of the inner layer also includes a flow modifier, and the weight ratio of low melt index polyethylene and flow modifier is (1-4): (0.01-0.02); the raw material of the outer layer also includes a flow modifier, and the weight ratio of low melt index polyethylene and flow modifier is (1-4): (0.01-0.02).

[0020] Furthermore, the flow modifier is prepared by the following method: under the protection of inert gas, ethyl 6-heptenoate and ethylenediamine are added to a mixture of ethanol and tetrahydrofuran, and the mixture is stirred for 18-22 hours, and then water is added, and the mixture is stirred for 0.5-1.5 hours, and sodium hydroxide is added, and the mixture is stirred for 4-6 hours, and then the pH value is adjusted to 4-5 with acid, and the mixture is stirred for 0.5-1.5 hours, and then the mixture is extracted, washed, and dried to obtain the flow modifier;

[0021] Among them, the molar ratio of 6-heptenoic acid ethyl ester, ethylenediamine and sodium hydroxide is 4:(1.1-1.5):(5-7).

[0022] Ethyl 6-heptenoate contains double bonds and ester groups, and ethylenediamine contains two amino groups. In a mixed solution of ethanol and tetrahydrofuran, the double bonds of ethyl 6-heptenoate and the amino groups of ethylenediamine react, and then the ester groups are hydrolyzed in the presence of water and sodium hydroxide, and then the pH value is adjusted to acidic to form carboxyl groups, and a flow modifier is further obtained. At this time, the flow modifier contains thirty-four carbons, four carboxyl groups, and two imino groups, and the energy transfer of low melt index polyethylene is changed through carbon, carboxyl groups, and imino groups, so that the chain segments are easily displaced, the fluidity of low melt index polyethylene is improved, the interface and internal stress between low melt index polyethylene and high density polyethylene and metallocene polyethylene are reduced, the crystal size is refined, and the tensile strength and heat sealing strength of the polyethylene film are improved.

[0023] In one embodiment, the molar ratio of 6-heptenoic acid ethyl ester, ethylenediamine, and sodium hydroxide is 4:1.3:6. The molar ratio of 6-heptenoic acid ethyl ester, ethylenediamine, and sodium hydroxide can also be adjusted to 4:1.1:5, 4:1.5:7, 4:1.1:5, etc. as needed, and the molar ratio of 6-heptenoic acid ethyl ester, ethylenediamine, and sodium hydroxide can achieve the above-mentioned technical effect when it is between 4:(1.1-1.5):(5-7).

[0024] Further, the weight ratio of the ethanol, tetrahydrofuran, 6-heptenoic acid ethyl ester and water is (20-30): (20-30): (3-5): (40-60). Preferably, the weight ratio of the ethanol, tetrahydrofuran, 6-heptenoic acid ethyl ester and water is 25:25:4:50. Within the above range, the flow modifier can be obtained, and when the weight ratio of ethanol, tetrahydrofuran, 6-heptenoic acid ethyl ester and water is 25:25:4:50, the effect is best.

[0025] In a second aspect, the present application provides a processing technology for the above-mentioned polyethylene film resistant to steam sterilization, which adopts the following technical solution:

[0026] A processing technology for the above-mentioned polyethylene film resistant to steam sterilization includes the following steps: preparing inner layer mixture, middle layer mixture and outer layer mixture, and then adding them into a three-layer co-extrusion film blowing machine, and obtaining a polyethylene film through melt extrusion, film blowing traction and converging nip rollers.

[0027] In a third aspect, the present application provides a sterile breathing bag, which adopts the following technical solution:

[0028] A sterile breathing bag comprises the above-mentioned polyethylene film resistant to steam sterilization.

[0029] By adopting the above technical solution, the application of polyethylene film is facilitated.

[0030] Optionally, it also includes Tyvek paper, and the Tyvek paper and polyethylene film are both square in shape. The three sides of the Tyvek paper and the three sides of the polyethylene film are heat-sealed to form a bag-like structure with one end open. A concave buckle sealing strip and a convex buckle sealing strip are arranged between the remaining side of the polyethylene film and the remaining side of the Tyvek paper, and the open end is sealed by the concave buckle sealing strip and the convex buckle sealing strip to achieve the sealing of the sterilized breathing bag.

[0031] The items to be sterilized are placed in a sterilized breathing bag and sealed, and then the breathing bag is sterilized together with the items to be sterilized, which facilitates the sealing of the items to be sterilized and the use of the breathing bag.

[0032] In summary, this application has at least the following beneficial effects:

[0033] The polyethylene film of the present application has no adhesion and deformation after being sterilized for 30 minutes at a steam temperature of 121°C, showing excellent resistance to steam sterilization. In addition, the polyethylene film has a tensile strength of ≥30Mpa and a heat-sealing strength of ≥20N / 15mm, making the polyethylene film show better mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the structure of the sterilized breathing bag of this application.

[0035] Figure 2 It is a schematic diagram of the structure of the polyethylene film of the present application.

[0036] Explanation of the reference numerals: 1, polyethylene film; 11, inner layer; 12, middle layer; 13, outer layer; 2, Tyvek paper; 3, concave buckle sealing strip; 4, convex buckle sealing strip. DETAILED DESCRIPTION

[0037] In order to make the present application easier to understand, the present application will be further described in detail below in conjunction with the examples, which are merely illustrative and are not intended to limit the scope of application of the present application. The raw materials or components used in the present application can be obtained through commercial routes or conventional methods unless otherwise specified.

[0038] Preparation Example

[0039] Preparation Example 1

[0040] A flow improver is prepared by the following method:

[0041] Under nitrogen protection, add 25 kg of tetrahydrofuran to 25 kg of ethanol and stir for 30 minutes. Then add 4 kg of 6-heptenoic acid ethyl ester and ethylenediamine and stir for 20 hours. Then add 50 kg of water and stir for 1 hour. Then add sodium hydroxide and stir for 5 hours. Then adjust the pH value to 4.5 with 5% dilute hydrochloric acid and stir for 1 hour. Then extract with ethyl acetate, using 50 kg of ethyl acetate. Then wash three times with saturated sodium chloride solution, using 50 kg of saturated sodium chloride each time, spin dry to obtain a flow modifier.

[0042] Among them, the molar ratio of 6-heptenoic acid ethyl ester, ethylenediamine and sodium hydroxide is 4:1.3:6.

[0043] Example

[0044] Table 1 Content of each raw material in the middle layer (unit: kg)

[0045] Example Example 1 Example 2 Example 3 HDPE 70 60 80 MPE(I) 30 40 20

[0046] Note: HDPE is high-density polyethylene; MPE(I) is metallocene polyethylene.

[0047] Table 2 Content of each raw material in the inner layer (unit: kg)

[0048]

[0049]

[0050] Note: HDPE is high-density polyethylene; MPE(I) and MPE(II) are both metallocene polyethylene.

[0051] Table 3 Content of each raw material in the outer layer (unit: kg)

[0052]

[0053] Note: HDPE is high-density polyethylene; MPE(I) and MPE(II) are both metallocene polyethylene.

[0054] Example 1

[0055] A polyethylene film resistant to steam sterilization, the polyethylene film has a horizontal width of 500 mm, and comprises an inner layer, a middle layer, and an outer layer which are arranged in sequence, the thickness of the inner layer is 0.03 mm, the thickness of the middle layer is 0.03 mm, the thickness of the outer layer is 0.03 mm, the raw material ratio of the middle layer is shown in Table 1, the raw material ratio of the inner layer is shown in Table 2, and the raw material ratio of the outer layer is shown in Table 3.

[0056] A processing technology for a polyethylene film resistant to steam sterilization comprises the following steps:

[0057] S0, preparation of high density polyethylene, metallocene polyethylene (I), metallocene polyethylene (II)

[0058] Among them, the melt index of high-density polyethylene is 0.99 g / 10 min; the melt index of metallocene polyethylene (I) is 1.20 g / 10 min; and the melt index of metallocene polyethylene (II) is 0.05 g / 10 min.

[0059] S1. Prepare the middle layer mixture, inner layer mixture and outer layer mixture

[0060] Preparation of the middle layer mixture: Add metallocene polyethylene (I) to high-density polyethylene and stir for 30 minutes to obtain the inner layer mixture.

[0061] Preparation of inner layer mixture: Add high density polyethylene and metallocene polyethylene (I) into metallocene polyethylene (II), stir for 30 minutes, and obtain inner layer mixture.

[0062] Preparation of outer layer mixture: Add high density polyethylene and metallocene polyethylene (I) into metallocene polyethylene (II), stir for 30 minutes, and obtain outer layer mixture.

[0063] S2, Film Blowing

[0064] The middle layer mixture, the inner layer mixture and the outer layer mixture are respectively added into a three-layer co-extrusion film blowing machine, and the polyethylene film is obtained through melt extrusion, film blowing traction and converging nip rollers.

[0065] Example 2-3

[0066] A polyethylene film resistant to steam sterilization, which is different from Example 1 in that the raw material ratios of the inner layer, the middle layer and the outer layer are different. The raw material ratio of the middle layer is shown in Table 1, the raw material ratio of the inner layer is shown in Table 2, and the raw material ratio of the outer layer is shown in Table 3.

[0067] Embodiment 4-5

[0068] A polyethylene film resistant to steam sterilization, which is different from Example 1 in that the raw material ratio of the inner layer and the raw material ratio of the outer layer are different. The raw material ratio of the inner layer is shown in Table 2, and the raw material ratio of the outer layer is shown in Table 3.

[0069] Example 6

[0070] A polyethylene film resistant to steam sterilization, which differs from Example 1 in that a flow modifier is also added to the inner layer raw material, the raw material ratio of the inner layer is shown in Table 2, and the flow modifier is prepared by Preparation Example 1. In the preparation method, the flow modifier is added together with the high-density polyethylene.

[0071] At the same time, a flow modifier is also added to the outer layer raw material. The raw material ratio of the outer layer is shown in Table 3, and the flow modifier is prepared by Preparation Example 1. In the preparation method, the flow modifier is added together with the high-density polyethylene.

[0072] Example 7

[0073] A polyethylene film resistant to steam sterilization, which is different from Example 6 in that the raw material ratio of the inner layer and the raw material ratio of the outer layer are different. The raw material ratio of the inner layer is shown in Table 2, and the raw material ratio of the outer layer is shown in Table 3.

[0074] Comparative Example

[0075] Comparative Example 1

[0076] A polyethylene film resistant to steam sterilization, which differs from Example 1 in that an equal amount of medium melt index polyethylene is used to replace low melt index polyethylene in the inner layer raw material, and an equal amount of medium melt index polyethylene is used to replace low melt index polyethylene in the outer layer raw material.

[0077] Performance Testing

[0078] The polyethylene films obtained in Examples 1-7 and Comparative Example 1 were taken as samples, respectively, and the following performance tests were performed on the samples. The test results are shown in Tables 4 and 5.

[0079] Among them, according to YBB00072005-2015 "Medicinal Low-density Polyethylene Film and Bag", the tensile strength, elongation at break and heat sealing strength of the samples were tested.

[0080] The conditions for resistance to steam sterilization are: steam temperature 121°C, sterilization treatment for 30 minutes.

[0081] According to YBB00272004-2015 "Determination of Insoluble Particles in Packaging Materials", the insoluble particles of the sample are tested, and the conditions for insoluble particles are: the internal surface area is 200cm 2 bag, 200mL of water for injection.

[0082] Table 4 Sterilization and intolerant particle test results

[0083]

[0084]

[0085] Table 5 Mechanical properties test results

[0086]

[0087] As can be seen from Table 4 and Table 5, the polyethylene film of the present application has no adhesion and deformation after being sterilized for 30 minutes at a steam temperature of 121°C, showing excellent resistance to steam sterilization. It also has high tensile strength and elongation at break, with a longitudinal tensile strength of 43.20-49.42Mpa, a transverse tensile strength of 32.79-42.07Mpa, a longitudinal elongation at break of 1334.76-1342.52%, and a transverse elongation at break of 1347.15-1347.15%. At the same time, it also has a high heat sealing strength of 25.84-30.46N / 15mm, so that the polyethylene film shows better comprehensive performance and meets market demand.

[0088] Comparing Example 1 with Examples 4-5, it can be seen that adding low melt index metallocene polyethylene (II) to high density polyethylene significantly improves the tensile strength and heat sealing strength of the polyethylene film as the amount of addition increases, making the polyethylene film exhibit higher mechanical properties. Combined with Examples 6-7, adding a flow modifier to metallocene polyethylene (II) can further improve the mechanical properties of the polyethylene film.

[0089] Application Examples

[0090] A sterile breathing bag, referring to Figure 1 and Figure 2 , including a polyethylene film 1 and a Tyvek paper 2, wherein the polyethylene film 1 includes an inner layer 11, an intermediate layer 12, and an outer layer 13 arranged in sequence. The polyethylene film 1 and the Tyvek paper 2 are both rectangular. The three sides of the Tyvek paper 2 and the three sides of the polyethylene film 1 are heat-sealed to form a bag-like structure with one end open. A concave buckle sealing strip 3 is fixedly provided on the remaining side of the polyethylene film 1, and a convex buckle sealing strip 4 is fixedly provided on the remaining side of the Tyvek paper 2. The concave buckle sealing strip 3 and the convex buckle sealing strip 4 are matched, and the open end of the sterilized breathing bag is sealed by the concave buckle sealing strip 3 and the convex buckle sealing strip 4.

[0091] The items to be sterilized are loaded into the open end of the sterilized breathing bag, and then the concave buckle sealing strip 3 and the convex buckle sealing strip 4 are buckled together and the open end is sealed, and then placed in a steam temperature of 121°C for sterilization for 30 minutes.

[0092] Furthermore, the polyethylene film 1 is any one of Examples 1-8, and the sterilized breathing bag obtained by using the polyethylene film 1 of any one of Examples 1-8 has qualified mechanical properties, insoluble particles, and resistance to steam sterilization. Moreover, the polyethylene film 1 and the Tyvek paper 2 are heat-sealed without cracking, and have good stability in use.

[0093] It should be noted that the embodiments described above are only used to explain the present application and do not constitute any limitation to the present application. The present application is described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present application may be modified as specified within the scope of the claims of the present application, and the present invention may be revised without departing from the scope and spirit of the present application. Although the present application described therein relates to specific methods, materials and embodiments, it does not mean that the present application is limited to the specific examples disclosed therein. On the contrary, the present application can be extended to all other methods and applications with the same functions.

Claims

1. A polyethylene film resistant to steam sterilization, comprising an inner layer, an intermediate layer, and an outer layer arranged in sequence, characterized in that: The middle layer is mainly made of medium melt index polyethylene; The inner layer is mainly made of medium melt index polyethylene and low melt index polyethylene, and the weight ratio of the medium melt index polyethylene to the low melt index polyethylene is 10:(1-4); The outer layer is mainly made of medium melt index polyethylene and low melt index polyethylene, and the weight ratio of the medium melt index polyethylene to the low melt index polyethylene is 10:(1-4); The medium melt index polyethylene is composed of high density polyethylene and metallocene polyethylene I, and the weight ratio of high density polyethylene and metallocene polyethylene I is (6-8): (2-4), and the low melt index polyethylene is composed of metallocene polyethylene II; The melt index of the high-density polyethylene is 0.99 g / 10 min, the melt index of the metallocene polyethylene I is 1.20 g / 10 min; the melt index of the metallocene polyethylene II is 0.05 g / 10 min, and the melt indexes of the high-density polyethylene, metallocene polyethylene I and metallocene polyethylene II are all obtained by ISO1133 detection.

2. A polyethylene film resistant to steam sterilization according to claim 1, characterized in that: The thickness of the middle layer is 0.02-0.05 mm, the thickness of the inner layer is 0.02-0.05 mm, and the thickness of the outer layer is 0.02-0.05 mm.

3. A process for processing a polyethylene film resistant to steam sterilization as claimed in any one of claims 1 to 2, characterized in that: The method comprises the following steps: preparing inner layer mixture, middle layer mixture and outer layer mixture, adding the mixture into a three-layer co-extrusion film blowing machine, and obtaining a polyethylene film through melt extrusion, film blowing traction and converging rollers.

4. A sterile breathing bag, characterized in that: The invention comprises a polyethylene film (1) resistant to steam sterilization as claimed in any one of claims 1 to 2.

5. A sterile breathing bag according to claim 4, characterized in that: The invention also comprises Tyvek paper (2), wherein the Tyvek paper (2) and the polyethylene film (1) are both square-shaped, and three sides of the Tyvek paper (2) and three sides of the polyethylene film (1) are heat-sealed to form a bag-like structure with one end open, and a concave buckle sealing strip (3) and a convex buckle sealing strip (4) are arranged between the remaining side of the polyethylene film (1) and the remaining side of the Tyvek paper (2), and the open end is sealed by the concave buckle sealing strip (3) and the convex buckle sealing strip (4) to achieve sealing of the sterilized breathing bag.

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