Piston for double-shot injection syringe and preparation method of piston

Abstract

The invention relates to the technical field of medicine packing materials, and provides a double-shot injection syringe piston which comprises a hard part, a soft part and silicone oil. The hard part comprises the following raw materials: polypropylene, an elastomer and polypropylene wax; the soft part comprises the following raw materials: polypropylene, an elastomer, polypropylene wax, a polymer A and an additive A; according to the double-shot injection piston for the injector and the preparation method of the double-shot injection piston, free silicone oil can be effectively prevented from being migrated into medicine in the injector.

Description

Technical Field

[0001] The invention relates to the technical field of drug packaging materials, and in particular to a double-color injection-molded syringe piston and a preparation method thereof. Background Art

[0002] The syringe is a commonly used medical device. The relevant principle was proposed as early as the 15th century. After years of development, it has formed a variety of different products. The material has also developed from metal to glass and plastic. The piston, as the sealing component of the syringe, has also developed into a variety of types such as bare plugs, coated and film-coated.

[0003] At present, pistons are mainly butyl rubber products. In order to improve clinical performance, syringes and pistons need to be siliconized to improve the sliding properties of pistons and syringes. However, the introduction of silicone oil poses a quality risk to some drugs. In particular, for prefilled syringes that are in contact with drugs for a long time, the risk of free silicone oil is greater.

[0004] Application Contents

[0005] The object of the present invention is to provide a two-color injection-molded syringe piston and a preparation method thereof, which can effectively prevent free silicone oil from migrating into the medicine in the syringe.

[0006] The embodiment of the present invention is realized by the following technical scheme: the piston for the two-color injection-molded syringe of the present invention comprises a hard part, a soft part and silicone oil; the raw materials of the hard part comprise polypropylene, an elastomer, and polypropylene wax; the raw materials of the soft part comprise polypropylene, an elastomer, polypropylene wax, polymer A, and additive A. The silicone oil mainly plays a lubricating role, and the silicone oil reacts and crosslinks with the active groups in additive A to form a cross-linked silicone oil layer on the surface. The cross-linked silicone oil can play a lubricating role, and the syringe does not need to be sprayed with silicone oil again, avoiding the quality risk caused by the free silicone oil infiltrating into the contents. The polypropylene wax mainly plays a lubricating role, and improves the demolding performance during the injection molding process.

[0007] Furthermore, in terms of weight, the content ratio of the hard part to the soft part is 3:2-4:1; the amount of the silicone oil is 0.001%wt-0.01%wt of the total of the soft part and the hard part.

[0008] Furthermore, in terms of weight, the hard part comprises 50-55 parts of polypropylene, 40-45 parts of elastomer, and 2-10 parts of polypropylene wax; the soft part comprises 40-50 parts of polypropylene, 40-50 parts of elastomer, 2-5 parts of polypropylene wax, 5-15 parts of polymer A, and 1-3 parts of additive A.

[0009] Furthermore, the elastomer in the hard part is one or more of SEBS (linear triblock copolymer), POE (polyorthoester), POP (vinyl polymer grafted polyether polyol), EPDM (ethylene propylene diene monomer rubber); the elastomer in the soft part is one or more of SEBS, POE, POP, EPDM. The addition of elastomer to the soft part can provide a changeable deformation capability, form a larger contact area with the syringe, and improve the sealing performance. The elastomer is added to the hard part to improve the compatibility with the soft part and prevent the soft part and the hard part from separating.

[0010] Furthermore, the polypropylene in the hard part is one of homopolymer polypropylene and random copolymer polypropylene, which can provide good hardness for the injection molded parts; the polypropylene in the soft part is one of random copolymer polypropylene and ternary copolymer polypropylene, which can provide good deformation and deformation recovery properties for the injection molded parts.

[0011] Furthermore, the polymer A in the soft part is one of cycloolefin polymer, cycloolefin copolymer and cyclic block copolymer, which is mainly used to increase the barrier property and drug compatibility of the piston and improve the protection of the contents.

[0012] Furthermore, the additive A in the soft part is one or more of polyhydroxyethyl acrylate and its copolymer, maleic anhydride modified polypropylene, and maleic anhydride modified polyethylene.

[0013] Furthermore, the silicone oil is hydrogenated silicone oil.

[0014] The present invention also provides a method for preparing a piston for a syringe based on the above-mentioned two-color injection molding, comprising the following steps:

[0015] (1) using an extruder to extrude the raw material of the hard part into particles A, and using an extruder to extrude the raw material of the soft part into particles B;

[0016] (2) putting particles A and B into a two-color injection molding machine for injection molding;

[0017] (3) After injection molding, spray silicone oil on the finished product to make it cross-linked.

[0018] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects: the two-color injection-molded syringe piston and the preparation method thereof of the present invention can ensure the lubricity of the piston without spraying silicone oil, and can effectively prevent free silicone oil from migrating into the drug in the syringe, thereby avoiding affecting the properties of the drug. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0020] Example 1

[0021] This embodiment provides a double-color injection-molded syringe piston and a preparation method thereof, comprising the following steps (wherein the extruder and the injection molding machine may use conventional parameters):

[0022] (1) Using an extruder to extrude the raw material of the hard part into particles A, and using an extruder to extrude the raw material of the soft part into particles B; wherein the components and contents are shown in Table 1 below;

[0023] (2) putting particles A and B into a two-color injection molding machine for injection molding;

[0024] (3) After injection molding, spray silicone oil on the finished product to make it cross-linked (the amount of silicone oil used is 0.002% of the total of the hard part and the soft part).

[0025] Table 1 Components and contents of Example 1

[0026]

[0027] Example 2

[0028] This embodiment provides a two-color injection-molded syringe piston and a preparation method thereof. The steps are the same as those in Example 1, except for the components and their contents. The components and their contents in this embodiment are shown in Table 2 below (the amount of silicone oil used is 0.005% of the total of the hard part and the soft part).

[0029]

[0030] Example 3

[0031] This embodiment provides a two-color injection-molded syringe piston and a preparation method thereof. The steps are the same as those in Example 1, except for the components and their contents. The components and their contents in this embodiment are shown in Table 3 below (the amount of silicone oil used is 0.01% of the total of the hard part and the soft part).

[0032]

[0033]

[0034] Experimental example

[0035] The results of sliding performance tests were carried out using the pistons prepared in Examples 1-3 in combination with syringe barrels, i.e., testing the maximum pulling force required to pull the piston to slide. The average pulling force was measured through multiple tests, wherein Example 1 was 7.38N, Example 2 was 8.5N, and Example 3 was 7.55N, all of which were significantly less than the 15N specified in the standard. This shows that the piston prepared by the present invention not only has good sliding performance, but also does not require the application of silicone oil, and can effectively reduce the migration of free silicone oil into the drug solution. For situations where drugs need to be pre-filled into syringes, the piston in the present application has greater advantages.

[0036] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A piston for a two-color injection-molded syringe, characterized in that: Including hard part, soft part and silicone oil; The raw materials of the hard part include polypropylene, elastomer, and polypropylene wax; The raw materials of the soft part include polypropylene, elastomer, polypropylene wax, polymer A and additive A.

2. The double-color injection-molded syringe piston according to claim 1, characterized in that: In terms of weight, the content ratio of the hard part to the soft part is 3:2-4:1; the amount of the silicone oil is 0.001%wt-0.01%wt of the total of the soft part and the hard part.

3. The piston for a double-color injection-molded syringe according to claim 1, characterized in that: In terms of weight, the hard part comprises 50 to 55 parts of polypropylene, 40 to 45 parts of elastomer, and 2 to 10 parts of polypropylene wax; The soft part includes 40-50 parts of polypropylene, 40-50 parts of elastomer, 2-5 parts of polypropylene wax, 5-15 parts of polymer A, and 1-3 parts of additive A.

4. The piston for a double-color injection-molded syringe according to claim 1, characterized in that: The elastomer in the hard part is one or more of SEBS, POE, POP, and EPDM; The elastomer in the soft part is one or more of SEBS, POE, POP and EPDM.

5. The piston for a double-color injection-molded syringe according to claim 1, characterized in that: The polypropylene in the hard part is one of homopolymer polypropylene and random copolymer polypropylene; The polypropylene in the soft part is one of random copolymer polypropylene and terpolymer polypropylene.

6. The double-color injection-molded syringe piston according to claim 1, characterized in that: The polymer A in the soft part is one of a cycloolefin polymer, a cycloolefin copolymer, and a cyclic block copolymer.

7. The piston for a double-color injection-molded syringe according to claim 1, characterized in that: The additive A in the soft part is one or more of polyhydroxyethyl acrylate and its copolymer, maleic anhydride modified polypropylene, and maleic anhydride modified polyethylene.

8. The double-color injection-molded syringe piston according to claim 1, characterized in that: The silicone oil is hydrogenated silicone oil.

9. The method for preparing a piston for a double-color injection-molded syringe according to any one of claims 1 to 8, characterized in that: The steps include: (1) using an extruder to extrude the raw material of the hard part into particles A, and using an extruder to extrude the raw material of the soft part into particles B; (2) putting particles A and B into a two-color injection molding machine for injection molding; (3) After injection molding, spray silicone oil on the finished product to make it cross-linked.

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