JPS60236750A - Resin laminate - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a resin laminate, and in particular to a resin laminate that is elastic and suppresses elution of plasticizer, and is therefore suitable for medical use, particularly for blood circuit tubes that come into contact with blood. This invention relates to a vinyl chloride resin laminate that can be suitably used for medical equipment such as the following.

(Prior Art) Resin molded products are used in various medical devices, such as blood bags for storing and transporting blood, tubes for blood circuits for artificial kidneys, and the like.

Resin molded articles for medical equipment used in applications that come into contact with blood need to be flexible so that they can be freely deformed and have no hemolytic properties. In particular, the blood circuit tubes In addition to being transparent so that the blood flowing inside the tube can be observed from the outside, the blood flow can be controlled at any time by tightening or removing a clamp from the outside of the tube, and the blood pump As with pump tubes used to circulate blood, an important characteristic is required to be able to sag elastically so that there will be no change in flow rate or rupture even if the tube is squeezed for a long time. Furthermore, you can wrap the tube around it,
Alternatively, the surface is also required to be non-adhesive so that the tubes do not stick to each other when stacked.

Conventionally, molded vinyl chloride resins containing a plasticizer such as dioctyl phthalate have been widely used for the above-mentioned medical devices because of their flexibility and transparency. However, molded products made of such vinyl chloride resins have a problem in that the plasticizer is eluted, albeit in a small amount. For this purpose, for example, JP-A-57-175365 proposes graft polymerizing vinyl chloride to an ethylene-vinyl acetate copolymer to obtain a soft and transparent resin that does not contain a plasticizer. However, since this resin has poor elasticity, it is not suitable for the tube part of the pump part of the blood circuit for artificial kidney dialysis, which requires high elasticity as described above.
Not suitable for use.

(Purpose of the Invention) As a result of intensive research in order to solve the above-mentioned problems in medical resin molded products, the present inventors have found that by graft polymerizing vinyl chloride to the above-mentioned ethylene-vinyl acetate copolymer. According to a laminate with an inner layer made of a plasticizer-free resin and an outer layer made of a vinyl chloride resin containing an appropriate amount of plasticizer to have high elasticity, plasticizers and low molecular weight resins are removed from the inner layer that comes into contact with blood. It has been found that it is possible to obtain a resin laminate in which the elution of substances is significantly suppressed and the outer layer has sufficient elasticity.

Therefore, an object of the present invention is to provide a resin laminate that suppresses the elution of plasticizers and low molecular weight substances, has excellent elasticity, and has no hemolytic properties, and is particularly intended for use in blood circuits as described above. It is an object of the present invention to provide a resin laminate that can be suitably used as a tube section of a pump section.

(Structure of the Invention) The resin laminate of the present invention has an outer layer made of a vinyl chloride resin containing a plasticizer, and an ethylene-vinyl acetate copolymer in which vinyl chloride is grafted or vinyl chloride is grafted onto the outer layer and an ethylene-vinyl acetate copolymer. It is characterized by being laminated with a copolymerizable monomer and an inner layer made of a cografted resin.

The vinyl chloride resin used as the outer layer in the present invention is
A plasticizer is blended with a homopolymer of vinyl chloride or a copolymer of vinyl chloride and a monomer that is copolymerizable with it (hereinafter, these may be referred to as vinyl chloride copolymers). . Examples of the monomers forming the vinyl chloride copolymer include acrylic acid, methacrylic acid, methyl acrylate, methyl acrylate, butyl acrylate, butyl mecacrylate, 2-ethylhexyl acrylate, stearyl acrylate, and stearyl methacrylate. Examples include (meth)acrylic acid and its esters, α-olefins such as ethylene and propylene, vinyl esters such as vinyl acetate and vinyl stearate, and vinyl ethers such as methyl vinyl ether and cetyl vinyl ether. In particular, among these, ethylene, butyl acrylate or 2-ethyl acrylate is preferably used.

In such a vinyl chloride copolymer containing a monomer unit having copolymerizability with vinyl chloride, the amount of this monomer unit is 20 parts by weight or less per 100 parts by weight of vinyl chloride unit. is preferable. Furthermore, the average degree of polymerization of the vinyl chloride copolymer is preferably 1,400 or more, particularly preferably 1,900 or more. If the average degree of polymerization is less than 1400, the vinyl chloride resin will have poor elasticity, making it unsuitable for molded products that require high elasticity, such as the pump tube described above.

The plasticizer contained in the vinyl chloride resin is not particularly limited, but preferably dioctyl phthalate, trioctyl trimellitate, polyester polymer plasticizers, etc. are used. In particular, trioctyl trimellitate and a polyester polymer plasticizer with a molecular weight of 1000 or more are preferably used.

These plasticizers are blended in an amount of 40 to 150 parts by weight, preferably 60 to 120 parts by weight, per 100 parts by weight of the vinyl chloride polymer. The amount of plasticizer blended is vinyl chloride polymer 1
If it is less than 40 parts by weight, the vinyl chloride resin will lack elasticity, while if it is more than 150 parts by weight, the resin will be too flexible and have poor elasticity. be.

The resin laminate of the present invention has an ethylene-vinyl acetate copolymer grafted with vinyl chloride on the outer layer as described above,
Alternatively, an inner layer made of a resin (hereinafter sometimes referred to as graft resin) in which vinyl chloride is cografted with a monomer having copolymerizability is laminated.

Here, as the above-mentioned ethylene-vinyl acetate copolymer, in addition to an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20 to 60%, ethylene, vinyl acetate, and a third monomer copolymerizable with these are used. A terpolymer with a polymer can be used. As this ternary copolymer, an ethylene-vinyl acetate-carbon oxide copolymer is preferably used, and in particular, the monomer units are 72 to 50% ethylene, 20 to 35% vinyl acetate, and 8 to 13% carbon oxide. % copolymers are preferred. Such copolymers are already known and can be obtained, for example, as "Elvaloy" (manufactured by DuPont).

Examples of monomers to be cografted with vinyl chloride into the ethylene-vinyl acetate copolymer include the monomers that are copolymerizable with vinyl chloride mentioned above. Similarly, ethylene and acrylic esters are particularly preferably used. In a cograft resin in which such a monomer is grafted onto an ethylene-vinyl acetate copolymer, these monomers having copolymerizability with vinyl chloride are contained in an amount of 20 parts by weight per 100 parts by weight of vinyl chloride units. It is preferable that it is below.

In the present invention, the above-mentioned graft resin includes 30 to 70% by weight of an ethylene-vinyl acetate copolymer and 70 to 30% by weight of a graft component consisting of a vinyl chloride unit or a polymer unit having copolymerizability with this and vinyl chloride. % by weight. Ethylene-vinyl acetate copolymer is 3
If the amount is less than 0% by weight, the flexibility of the resin will be poor, causing problems in practical use, while if it is more than 70% by weight, for example, the strength of the resin will be insufficient and the adhesiveness of the resin will deteriorate. This is because it increases.

The resin laminate of the present invention is formed by laminating the outer layer and the inner layer as described above, and can be manufactured using a normal two-layer extruder, including the case of a tube, for example.

Since the resin laminate of the present invention has high elasticity, it is suitable as a blood circuit tube and a pump tube as described above. In this case, it is preferably in the range of 0.1 to 1. When the inner layer is thicker than the outer layer, the elasticity of the tube is not sufficient, and when it is less than 0.1 times the outer layer, plasticizers and low molecular weight substances will elute from the outer layer into the blood via the inner layer. It is from.

In addition, in the resin laminate of the present invention, in both the outer layer and the inner layer, calcium stearate,
Stabilizers such as zinc stearate and magnesium oxide, phenol-based and phosphite-based antioxidants, epoxy-based plasticizers, and the like can be appropriately contained. Furthermore, in order to improve melt wettability during molding and prevent adhesion to the mold, a polyethylene-based, acid amide-based, or ester-based lubricant may be included.

(Effects of the Invention) As described above, in the resin laminate of the present invention, the inner layer is made of a graft resin that does not contain a plasticizer, and the outer layer is made of a highly elastic vinyl chloride resin that contains a plasticizer. The inner layer prevents the contained plasticizer from leaching into the blood or infusion, and the outer layer provides the resin laminate with high elasticity, so the blood circuit tube can be suitably used in various medical devices. .

(Example) The present invention will be explained below with reference to Examples.

As shown in the example table, trioctyl trimellitate and molecular weight 2 were added to polyvinyl chloride with an average degree of polymerization of 1900 or 2900.
000 polyester plasticizer or dioctyl phthalate, and epoxidized soybean oil and Ca-Zn.
After adding an appropriate amount of a system stabilizer, the mixture was kneaded and pelletized to prepare resin composition pellets for the outer layer.

Separately, vinyl chloride was graft-polymerized to an engineered tylene-vinyl acetate copolymer having a vinyl acetate content of 26% or 40% by ordinary suspension polymerization to obtain a graft resin. Appropriate amounts of epoxidized soybean oil and a Ca-Zn stabilizer were added to this resin, which was then kneaded and pelletized to prepare inner layer resin composition pellets.

In the tables, numbers for outer layer and inner layer indicate parts by weight unless otherwise specified.

Using these outer layer and inner layer resin composition pellets,
Outer diameter wall thickness approx. 12++m, inner layer thickness approx. Q, 5++m,
A two-layer tube with an outer layer thickness of approximately 1.5 fins was formed by two-layer extrusion molding. The results of evaluating the physical properties of this tube are shown in the table.

Further, as a comparative example, a single-layer tube having an outer diameter of 12 mm and a wall thickness of 2 mm was manufactured using the inner layer resin composition pellets or the outer layer resin composition pellets alone. The physical properties of these tubes are also shown in the table.

According to the tube of the comparative example, the elution of the plasticizer is significant or the deformation due to ironing is significant, but according to the tube of the present invention, the elution of the wicking agent is suppressed, the rate of deformation due to ironing is small, and cracking does not occur. do not have.

The amount of plasticizer eluted was measured as follows. That is, the outer diameter 1
A plasticizer was extracted by circulating 700 ml of a 40% by weight ethanol aqueous solution at a rate of 300 ml/min at 40° C. for 6 hours using a blood pump in a test tube of 2 dragons, inner diameter 8II11, and length 4Qcm. Next, 100 ml of this ethanol aqueous solution was evaporated to dryness, methanol was added to make a predetermined amount, and this was subjected to liquid chromatography to separate and quantify the plasticizer.

In addition, the hemolysis test, eluate test, and elasticity test were conducted in the Showa 5
The test was carried out in accordance with the blood circuit test in the approval standards for dialysis-type artificial kidney devices in Pharmaceutical Notification No. 494 dated June 20, 1988.

Patent applicant Sekisui Chemical Co., Ltd. Representative Mototoshi Fujinuma

Claims (1)

[Claims] (1) Vinyl chloride is grafted onto an outer layer made of a vinyl chloride resin containing a plasticizer and an ethylene-vinyl acetate copolymer, or vinyl chloride is co-coated with a monomer that is copolymerizable with the outer layer. A resin laminate comprising an inner layer made of a grafted resin. 2. The resin laminate according to claim 1, wherein the inner layer and the outer layer form a two-layer tube.