JPS6284768A - Medical resin molded article - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to blood bags, medical solution bags, and blood transfusions.

This invention relates to infusion tubes, blood circuits, and other medical resin molded products.

(Prior Art and its Problems) In recent years, many medical instruments have become disposable, and blood bags, drug solution bags, infusion tubes, drip tubes, etc. are made of synthetic resins and resins.

This synthetic resin material is required to have sufficient heat resistance to withstand autoclave sterilization, as well as excellent cold resistance and flexibility.Currently, polyvinyl chloride is used as a material that satisfies all of these requirements. Resin is used as the top.

However, this polyvinyl chloride is particularly difficult to use when making flexible and transparent molded products such as blood bags.
There was a risk that the plasticizer would gradually dissolve and enter the body and cause adverse effects.

Research is currently underway to prevent this.
One such system is ethylene-vinyl acetate copolymer (hereinafter referred to as EV A Jl'ffi), which replaces polyvinyl chloride.
(abbreviated as "coalescence") has been noted [I.

EVA Kyodogogai has properties superior to polyvinyl chloride resin in terms of flexibility, transparency, and cold resistance, but it has the disadvantage of heat resistance and cannot withstand the high temperatures of autoclave sterilization. There's a problem.

Therefore, Japanese Patent Application Laid-Open No. 55-76955 and Japanese Patent Application Laid-open No. 58-
As described in Publication No. 73370, etc., EVA
By irradiating the copolymer with an electron beam and crosslinking it, it became possible to obtain physical properties that could withstand autoclave sterilization (121'c, 20 minutes).

However, when this EVA copolymer is made into a bag shape and subjected to electron beam irradiation, the irradiation! , ) is higher, the problem is that blocking between inner surfaces becomes more severe. Further, it is known that cross-linked EvAJuffi coalescence has extremely low weldability with a high frequency welder or the like.

For this reason, as proposed in JP-A-58-73370, when welding accessories, uncrosslinked E
Attempts have been made to weld welding through an intervening layer made of VA copolymer, but this method requires the preparation of a small tube to serve as an intervening layer for each part and the effort of attaching it, resulting in high cost and problems. This is disadvantageous in terms of workability.

The present invention was proposed as a result of repeated studies to solve the following two problems, and it does not cause inner blocking during electron beam irradiation, and has good welder strength and heat resistance. The purpose of this invention is to provide a medical resin molded product. - (Means for solving the problems) The present invention provides crosslinked areas and low crosslinked areas and/or non-crosslinked areas at intervals on the surface of a medical molded article of ethylene-vinyl acetate copolymer. It is something that forms.

Specifically, the surface of the EVA copolymer molded product is irradiated with an electron beam to form crosslinked portions into, for example, a mesh shape! ! The remaining portion of the crosslinked portion is either an unavoidable low crosslinked portion or an uncrosslinked portion. When irradiating electron beams, cover the surface of the molded object with mesh-like aluminum foil.

It is best to cover it with stainless steel or other shielding material.

In order to prevent inner surface blocking during irradiation, electron beam irradiation should be performed at a low Hifit (3 to 10 Mrad) a) It is preferable to irradiate the electron beam in parts (multiple irradiations) at 7X.

Further, the average gel fraction of the crosslinked portion and the low crosslinked portion and/or the uncrosslinked portion is preferably 40 to 70%.

Blood bags are also used as medical molded products.

These include blood circuit tubes, infusion fluids, blood transfusion tubes, trip chambers, catheters, etc.

(Function) The surface of the EVA copolymer molded product has crosslinked parts, low crosslinked parts and/or
Alternatively, since it is composed of uncrosslinked parts, heat resistance is ensured by the crosslinked parts. Furthermore, the presence of the low crosslinked portion and/or the uncrosslinked portion ensures weldability and at the same time prevents inner surface blocking due to electron beam irradiation.

(Example) The surface of an EVA copolymer inflation tube was
It was covered with an aluminum mesh with an area ratio of irradiated and unirradiated parts of 1:1, and electron beam irradiation was performed under the following conditions, and the gel fraction (xylene 100ml, 110°C, 24hv) and welder strength were examined.

゛The directionality of the electron beam is not only straight, but also reflective.

Although the gel fraction is slightly higher due to phenomena such as interference, there is almost no difference in the gel fraction between the front and back surfaces of the tube.

In addition, almost satisfactory welder strength (I1) was obtained. In addition, inner surface protrusion of these samples did not occur during electron beam irradiation, and there were no problems with heat resistance during autoclave sterilization.

(Effect) As is clear from the following examples, according to the present invention, E
When the VA copolymer is used as a medical resin molded article, it is possible to prevent inner surface blocking during electron beam irradiation, and to maintain high frequency welder strength and heat resistance within a practical range.

Patent Applicant Kawasumi Kagaku Shigyo Co., Ltd. Agent Patent Attorney Shigeru Nishino Beautiful Procedural Amendment (Hakuten 61.1.13 Patent Office Commissioner Unatsu) 1 Ryo P. (Patent Office Examiner) 1
Indication of the case Showa 3θ Year Patent Application No. 22≠7FS No. 2 Name of the invention Mameeri Katakyo 1 Ritsuichi 3 Person making the amendment 4 Agent Address: 1-22 Nishi-Shinbashi, Minato-ku, Tokyo 105 J No. 5 System Life Society #Ogyu (Contents of 1-quote amendment 1 rl on page 6, line 4 of the specification of the present application, 00 layer 1゜11
The one that says 0℃, 24hVJ is rloosl.

Corrected to 110℃, 24hrJ.

that's all

Claims (1)

[Claims] A medical molded article of ethylene-vinyl acetate copolymer, characterized in that crosslinked areas and low crosslinked areas and/or uncrosslinked areas are formed at intervals on the surface of the formed article. resin molded products.