KR101273049B1 - Polyolefin resin composition and multi-layer film including it - Google Patents

Abstract

The present invention relates to a medical multilayer film having excellent flexibility and transparency, wherein the outer layer is composed of A: polypropylene homopolymer, B: copolymer of propylene and alpha olefin or blends thereof (A + B), and a central layer. Silver C: 100 parts by weight of a heterophasic propylene / alpha olefin copolymer resin comprising a propylene / alpha olefin rubber copolymer (wherein alpha olefin is 2 to 50 wt%) as a matrix polymer, the inner layer is B resin or C resin, or A D: ethylene alpha olefin copolymer is prepared from a resin composition containing 5 to 20 parts by weight based on 80 to 95 parts by weight of a resin composed of these blends. The film of the present invention is excellent in transparency, heat resistance, flexibility and heat adhesion can be effectively used as a medical fluid container.

Medical fluid container, multilayer film, flexibility, transparency, heat adhesiveness

Description

Polyolefin resin composition and multi-layer film including the same {Polyolefin resin composition and multi-layer film including it}

The present invention relates to a polyolefin resin composition, and more particularly, to a medical multilayer film excellent in transparency, heat resistance, flexibility, and heat adhesion, which are physical properties required for a medical fluid container, and a polyolefin resin composition forming the same.

The present invention relates to a resin composition for an infusion container excellent in heat resistance, transparency and flexibility.

Conventional medical sap containers are predominantly glass bottles, and are still used in large quantities, but have been changed to light and soft polyvinyl chloride (PVC) bags due to ease of handling. However, the controversy of stability due to the plasticizer added to the PVC bag and the problem of environmental hormones has emerged, and the development of non-PVC fluid containers has been made.

Non-PVC-based sap packaging has the advantages of ease of handling, disposal and high temperature sterilization of soft PVC bags, and there are no human hazards and environmental problems caused by plasticizers. Form.

However, such non-PVC film can be used as a medical fluid container for high flexibility, easy to handle and easy disposal after use, transparency to check for internal contamination, biohazard and mechanical properties, and high temperature sterilization under 121 ℃ sterilization conditions. It has to satisfy various requirements such as sterilization, heat sealability and impact resistance. For the film that satisfies these properties, there is a need for a material having excellent heat resistance after high temperature sterilization, no deformation of appearance, and maintaining excellent transparency and flexibility.

Generally used isotactic polypropylene and its alpha olefin copolymer have sufficient heat resistance and thus can be sterilized at high temperature, but transparency and flexibility are degraded due to recrystallization during sterilization.

U. S. Patent No. 6,027, 776 discloses a multilayer film comprising an inner layer comprising an ethylene / alpha olefin copolymer, a second outer layer consisting of polypropylene or a high density polyethylene and a copolyester, the film having excellent flexibility. However, transparency is reduced due to the occurrence of whitening when sterilizing at 121 ℃. In addition, a medical film using an ethylene / alpha olefin copolymer as a soft layer has been disclosed, but the film must be cross-linked to impart heat resistance. This makes processing difficult, lowers productivity, and causes problems in disposal and incineration.

According to Japanese Patent No. 9-52328, a polypropylene resin layer made of syndiotactic propylene and a propylene-ethylene copolymer and a polypropylene resin layer made of an ethylene-alpha olefin copolymer using a metallocene catalyst are laminated. Transparency and flexibility are improved, but transparency is lowered due to the occurrence of whitening when sterilizing at 121 ℃.

Japanese Patent Laid-Open No. 9-59455 discloses a medical bag composition comprising a propylene-based propylene-alpha olefin copolymer, a hydrogenated styrene rubber, and a nucleating agent. The composition has excellent impact resistance and whitening after sterilization. None but lacks transparency and flexibility.

In order to solve such a problem, International Publication No. WO97 / 34951 used a composition composed of polypropylene, SEBS (styrene-ethylene-butylene-styrene copolymer), and a plasticizer. However, in order to give a satisfactory level of flexibility using this composition, a considerable amount of softener is required, resulting in a decrease in workability due to a lack of melt strength, resulting in a decrease in yield and a decrease in mechanical strength.

In Korean Patent No. 10-0344924, the outer layer is composed of a polypropylphen homopolymer, an propylene-based alpha olefin copolymer or a blend thereof, and the central layer is a propylene resin containing amorphous polypropylene, and hydrogenated. A resin composition made of styrene butadiene rubber, and an inner layer have been disclosed a method characterized in that the propylene-based alpha olefin copolymer, which is difficult to manufacture, and has a problem of low flexibility.

In order to solve the problems as described above, an object of the present invention is to provide a medical multilayer film excellent in transparency, flexibility, heat resistance, heat adhesion and impact properties required for medical fluid containers and polyolefin-based resin composition which comprises the same. do.

The polyolefin resin composition according to the present invention is characterized by consisting of 100 parts by weight of a heterophasic propylene / alpha olefin copolymer comprising a propylene / alpha olefin rubber copolymer (wherein alpha olefin is 2 to 50 wt%) as a matrix polymer.

In addition, the multilayer film according to the present invention relates to a medical multilayer film excellent in flexibility and transparency, the outer layer is A: polypropylene homopolymer, B: copolymer of propylene and alpha olefin or blends thereof (A + B) And the central layer is 100 parts by weight of a heterophasic propylene / alpha olefin copolymer resin comprising a propylene / alpha olefin rubber copolymer (wherein alpha olefin is 2 to 50 wt%) as C: matrix polymer, and the inner layer is B resin. Or D: ethylene alpha olefin copolymer is prepared from a resin composition containing 5 to 20 parts by weight based on 80 to 95 parts by weight of a resin composed of C resin or a blend thereof. The film of the present invention is excellent in transparency, heat resistance, flexibility and heat adhesion can be effectively used as a medical fluid container.

At this time, when the content of the ethylene alpha olefin copolymer in the inner layer composition is 20% or more, flexibility and transparency are lowered, and impact strength and thermal adhesiveness during low temperature storage are reduced.

The present invention relates to a multilayer film and a resin composition excellent in flexibility and transparency at high temperature sterilization, characterized in consisting of three layers.

The present invention provides a multi-layer film, characterized in that the melting point of the resin constituting each layer is an outer layer: 140 to 166 ° C, a center layer, and an inner layer: 130 to 160 ° C.

At this time, if the melting point of the outer layer is 140 ℃, the melting point of the central layer and the inner layer is less than 130 ℃ may cause heat deformation of the resin during sterilization. In particular, in the case of the inner layer, a substance may be eluted into the contents. Further, if the melting point of the outer layer is 166 ° C or higher, the flexibility is reduced. If the melting point of the central layer and the inner layer is 160 ° C or higher, the thermal adhesiveness, transparency, and flexibility are reduced.

Medical infusion containers are to be sterilized at 121 ° C after filling the contents. At this time, the material to be deformed or eluted should be less than the prescribed value, and therefore have good heat resistance. This is because the outer layer should be the best heat resistance to the first contact portion during sterilization.

Melting point 145 ° C. for polypropylene homopolymers, melting point 145 for heterophasic propylene / alpha olefin copolymers comprising propylene / alpha olefin rubber copolymers (wherein alpha olefins are 2-50 wt%) as matrix polymers The melting point is 145 ~ 166 ℃ when the mixture of these.

At this time, when the alpha olefin content is 2% or less, it is difficult to expect a heat resistance effect, and when it is 50% or more, transparency and workability are poor.

Transparency is important for medical sap containers to visually determine whether the drugs stored in the medical sap containers are of the proper type and whether the drugs are altered or contaminated. Therefore, the transparency is preferably 90% or more. In addition, the polypropylene resin is suitable for a multi-layered configuration without the need for a separate adhesive resin from the outer layer, the center layer, and the inner layer.

The middle layer of the present invention uses a heterophasic propylene / alpha olefin copolymer (a) comprising a propylene / alpha olefin rubber copolymer (wherein alpha olefin is 2 to 50 wt%) as the matrix polymer, which is the transparency of the film. It shows excellent transparency and flexibility without using hydrogenated styrene-butadiene rubber, which is widely used for improving the flexibility and flexibility. Ethylene and 1-butylene were used as alpha olefins. The melt index of the heterophasic polymer is preferably from 1 to 20 g / 10 minutes. If the melt index is 1 g / 10 minutes or less, the desired degree of transparency cannot be obtained. If the melt index is 20 g / 10 minutes or more, workability is poor. The inner layer of the present invention is composed of a copolymer of alpha olefins based on propylene. The inner layer is the part which is in direct contact with the medicine, and the part where adhesion occurs when sealing the container, in particular, the adhesive strength and the adhesion temperature are important. Therefore, a lower melting point is used than other layers. And a small amount of ethylene alpha olefin copolymer is used to improve the heat adhesion.

 Although the following examples will be described in more detail, the examples should not be construed as limiting the invention.

< Example 1  >

Ⓐ 50 parts by weight of polypropylene random copolymer with melt index (230 ℃, 2.16kg) 7.0g / 10min and ethylene content of 3.5wt%, b) propylene homopolymer 50 with melt index (230 ℃, 2.16kg) 8.5g / 10min The parts by weight were mixed in a mixer and then extruded with a twin screw extruder having a diameter ratio of 34 to use the pelletized composition as the outer layer. Also used as the middle layer is a heterophasic propylene / alpha olefin copolymer resin comprising a propylene copolymer having a butene-1 content of 14 wt% and a propylene / 1-butene rubber copolymer comprising 40 wt% of 1-butene as the matrix polymer. 90 parts by weight of a propylene copolymer having a butene-1 content of 14 wt% and a melt index (230 ° C., 2.16 kg) of ethylene alpha olefin of 7.0 g / 10 min. The pellet-like composition obtained by extruding 10 parts by weight of the copolymer by a twin screw extruder was used as the inner layer. Thereafter, a three-layer film having a thickness of the outer layer / middle layer / inner layer was 10 µm / 180 µm / 10 µm using a three-layer film molding machine. The film properties measured the haze before sterilization, heat resistance, that is, haze after sterilization (121 ° C., transparency after steam sterilization for 30 minutes), flexural modulus, and thermal adhesiveness, and the results are shown in Table 1.

Haze was measured according to ASTM D-746. That is, the film of 200 micrometers was shape | molded and measured using the haze meter.

Flexural modulus was measured according to the ASTM-D790 method. Specimens of 12.7 mm (width) x 127 mm (length) x 6 mm (thickness) were molded and measured using a flexural modulus meter.

Thermal adhesion was inspected after adhesion for 2 seconds at 140 ~ 150 ℃, 2KG pressure. Medical sap containers are made in the form of bags by the adhesion of the inner layer between the multilayer films, where a heat source is first applied to the outer layer and transferred to the interior, whereby the deformation of the outer layer does not occur due to the heat to bond the inner layer. Thermal adhesiveness was judged.

On the other hand, the melt index was measured at 230 ° C by ASTM D-1238 method. Melt index refers to the amount of thermoplastic resin (g) that can pass through an orifice of 2.09 mm diameter within 10 minutes at a certain pressure (2.16 kg) and temperature (230 ° C.).

Melting temperature was measured using DSC according to ASTM D-2117 method.

< Example 2 >

 All conditions were performed in the same manner as in Example 1 except that the content of ⓐ was 100 parts by weight.

< Example 3 >

All conditions were performed in the same manner as in Example 1 except that the content of ⓑ was 100 parts by weight.

< Example 4 >

All conditions were carried out in the same manner as in Example 1 except for using propylene instead of 6.5 g / 10 min ethylene and butene-1 propylene terpolymers of 3.5 wt%.

< Example 5 >

All conditions were carried out in the same manner as in Example 1 except for using propylene instead of a propylene random copolymer having an ethylene content of 4.5 g% of 4.5 g / 10 min.

< Comparative example  1>

All conditions were carried out in the same manner as in Example 1 except that the content of ⓒ was 100 parts by weight.

< Comparative Example 2 >

Ⓓ was performed in the same manner as in Example 1 except for adding 10 parts by weight of hydrogenated styrenebutadiene rubber having a melt index (230 ° C., 2.16 kg) of 3.5 g / 10 min.

[Table 1]

Haze (%) Flexural modulus
(kg / cm ² ) Thermal adhesion Before sterilization After sterilization Example 1 3.1 4.8 2800 good Example 2 2.1 5.3 2600 good Example 3 4.2 5.9 3200 good Example 4 3.2 5.1 3000 good Example 5 2.9 4.8 3200 good Comparative Example 1 3.1 5.1 2900 Bad Comparative Example 2 4.2 6.3 2800 usually

The present invention can obtain a transparent resin composition having excellent physical properties and flexibility required for medical fluid containers without using hydrogenated styrene butadiene rubber and a nucleating agent, and a medical multilayer film having excellent transparency, flexibility and heat resistance using the same.

Claims (3)

delete In a multilayer film comprising an outer layer, a middle layer and an inner layer, the outer layer consists of a polypropylene homopolymer, a copolymer of propylene and an alpha olefin or blends thereof, wherein the middle layer is a propylene / It consists of a polyolefin resin composition consisting of 100 parts by weight of a heteropropylene propylene / alpha olefin copolymer resin comprising an alpha olefin rubber copolymer (wherein alpha olefin is 2 to 50% by weight), the inner layer of propylene and alpha olefin A multilayer film comprising 5 to 20 parts by weight of an ethylene alpha olefin copolymer with respect to 80 to 95 parts by weight of a resin composed of a copolymer or the polyolefin resin composition or a blend thereof. 3. The method of claim 2, Melting | fusing point of resin which comprises the said outer layer is 140-166 degreeC, The melting | fusing point of resin which comprises the said center layer and an inner layer is 130-160 degreeC, The multilayer film characterized by the above-mentioned.