CS259234B1 - Polyolefin-based polymer composition suitable for the manufacture of syringe cylinders - Google Patents

Abstract

The purpose of the solution is a polyolefin mixture with reduced formation of a crystalline phase compared to pure polypropylene, intended specifically for the production of syringe barrels. The stated purpose is achieved by the addition of ethylene-vinyl acetate copolymer and propylene polymers. The created mixture has a reduced content of the crystalline phase compared to the pure polymer, which will have a positive effect on the quality of the produced syringe barrels. The subject of the solution can be used for the production of sanitary and laboratory aids such as, for example, measuring cylinders, baby bottles, syringe barrels, eye droppers, Petri dishes. Furthermore, in agriculture for the production of tunnel covers for vegetable ripening, etc.

Description

259234

The present invention relates to a polyolefin-based polymer blend suitable for the manufacture of syringes. Currently, polypropylene of different molecular weights is used for the manufacture of disposable syringe cylinders. The ratio of the individual types of polypropylene provides functionally the properties of the rolls produced. The disadvantage of the prior art composition is that the solidification of the polypropylene builds up a relatively high crystalline content, resulting in a relatively high shrinkage of the produced sprays, and in the syringes cylinders this results in an increase in the plunging force of the pistons into the cylinders, as well as the increased modulus values. bending or deteriorating transparency. Polypropylene spray dimensions can be modified in several ways. This is either a process for the processing of the polymer or the addition of nucleating agents, as described in AO No. 1 -971,831. While the additive additive ensures stabilization of the polypropylene spray dimensions, it also increases the stiffness of the material used, which is disadvantageous from the point of view of the manufacture of syringes. However, the repair of polypropylene sprays by regulating the technological mode, due to the nature of production and manufacturing equipment, cannot be fully realized.

These drawbacks are remedied by the polyolefin-based polymer blend, which is suitable for the manufacture of syringe cylinders, which consists of propylene polymers and propylene-ethylene polymers and ethylene vinyl acetate copolymer. The polypropylene content of the mixture is 70-90% by weight, the vinyl acetate content is 30-10% by weight. The benefits lie! in that, upon solidification, the resulting melt forms a small crystalline phase and a lower degree of secondary crystallinity, which guarantees dimensional stability of the products over long term storage. A further advantage of the present invention is that it arises! the mixture can be processed as a physical mixture without prior melting. individual components. Example 1

Isotactic polypropylene-3 having a melt index of 9.5 g / 10 min with a specific gravity of 910 kg.m was used as the base polymer for the preparation of the polymer blend. The polypropylene used contained 0.1 wt. % of a conventional phenolic antioxidant and 0.6 wt. of higher fatty acid amide by carbon number C17_22 · To the base polymer with a melt index of 0.7 g / 10 min and 10% by weight of ethylene vinyl acetate copolymer with a melting index of 4 g / 10 min. The vinyl acetate content of the ethylene vinyl acetate copolymer was 12% by weight. The ethylene content of the propylene ethylene copolymer was 1.8% by weight. The polymer blend was prepared by mixing the individual components with a fluidized-bed technique followed by granulation at a melt temperature of 220 ° C.

Crystallization of the samples was monitored dilatometrically. A glass cylinder dilatometers was used, dividing 0.002 cm 3 with a volume of 0.3 cm 3. A 1 g weight was used. Crystallization temperature 137.5 ° C

The crystalline phase of the mixture thus prepared was 59.6%.

The content of the crystalline phase used to date for the roll-making composition was 65.8% by weight. Example 1

Isotactic polypropylene with a melt index of 4 g / 10 min with a specific gravity of 910 kg.m-3 was used as the base polymer for the preparation of the polymer mixture. The polypropylene used contained 0.1 8 wt. % of a common phenolic antioxidant and 0.6% of higher fatty acid amide (C22-22). propylene ethylene copolymer and 10 wt. ethylene vinyl acetate copolymer. Copolymers used as in Example 1. Preparation and measurement of crystallization as in Example 1. The crystalline phase content was 57.3%.

Claims (1)

Example 3 Basic polypropylene as in Example 1. 20% by weight of isotactic polypropylene having a melt index of 0.8 g / 10 min and 20% ethylene-vinyl acetate copolymer was added to the base polypropylene. Ethylene vinyl acetate copolymer used as in Example 1. Preparation of the mixture and measurement of crystallization as in Example 1. The crystalline phase content of the prepared composition was 54.3% by weight. Example 4. Basic polypropylene as in Example 2. 20% by weight of propylene methylene copolymer with a melting index of 4.5 g / 10 min and 10% by weight were added to the base polymer. ethylene vinyl acetate copolymer with a melting index of 2 g / 10 min. Ethylene content in propylene methylene copolymer 15 wt. The vinyl acetate content of the ethylene vinyl acetate copolymer was 8% by weight. the preparation of the composition and the measurement of crystallization as in Example 1. The crystalline phase content of the prepared composition was 51.2%. The subject matter of the invention can be used for the production of sanitary and laboratory aids such as e.g. measuring cylinders, baby bottles, cylinders of syringes, eye drops, petrihomisky. Furthermore, in the field of agriculture for the production of tunnel coverings for vegetables and the like. OBJECT OF THE INVENTION A polyolefin-based polymer blend suitable for the manufacture of syringe cylinders, characterized in that it comprises 60 to 80 wt. polymers of propylene with a melting index of 4 to 11 g / 10 min, 20 to 10 wt. polymers of propylene-ethylene with an ethylene content of 1 to 20 wt. ethylene vinyl acetate copolymer melt index 2 to 5 g / 10 min containing 7 to 18 wt. vinyl acetate.