JPH0764045B2 - Laminates and packages - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is suitable for radiation sterilization after packaging articles that have excellent radiation resistance, good heat shaping properties, etc. and that require sterilization. The present invention relates to a polyolefin-based laminate and a package formed by forming the laminate.

[Conventional technology and its problems]

Polypropylene is highly transparent and is used as a raw material for various molded products. When it is used as a medical instrument or as a packaging for medical instruments, it should be exposed to radiation such as gamma rays and electron beams for the purpose of sterilization. There is. At that time, these molded products have a problem that they are deteriorated by radiation, the tensile elongation is lowered, the impact resistance is deteriorated, and further, the deterioration after irradiation progresses with time and the molded product is significantly embrittled.

As a method for preventing this deterioration, a method of adding a hindered amine compound or the like to a polyolefin resin partially added with polyethylene having higher radiation resistance than polypropylene (JP-A-55-19199, 58-42638, etc.), or a hindered amine It is known that polypropylene, ethylene-propylene random or block copolymers are preferable as the basic polymer to which the system compounds are added (JP-A-58-49737), and the latter has an ethylene content of 2.5 wt% (hereinafter %) Ethylene-propylene copolymer to which a hindered amine compound is added.
However, it has not been possible to sufficiently prevent deterioration of physical properties after gamma ray irradiation, particularly tensile elongation and impact resistance.

The high-impact ethylene-propylene copolymer is obtained by a known method in which ethylene-propylene rubber is blended with polypropylene or a polypropylene chain is bonded to the polypropylene chain by block polymerization. However, these ethylene-propylene copolymers,
It is opaque and the contents are difficult to see when it is used as a package, and further it is not possible to sufficiently prevent deterioration of the physical properties after gamma ray irradiation.

Further, for example, when packaging a syringe or the like and sterilizing by radiation, it is convenient to form the product by vacuum molding or the like according to the content, and fit and store the content in this, and at that time, polyethylene is Has a lower melting point than polypropylene,
Molding is difficult due to poor heat resistance.

That is, polyethylene is superior in radiation resistance to polypropylene, but is inferior in transparency and heat resistance, and has advantages and disadvantages.

[Problems to be solved by the invention]

By the way, the conventional radiation-resistant packaging, various forms of polyolefin-based resins, in combination in various ratios, or even if further additives are added, some of the drawbacks of polyethylene or polypropylene are expressed, No product with good balance of all physical properties was obtained.

The present inventors have conducted extensive studies to obtain a packaging body mainly composed of polyolefin and in which each of the defects is suppressed, and as a result, found that each of the defects can be suppressed by a laminate of a special blend composition. did.

The present invention has been made based on the above findings, and an object of the present invention is to provide a good laminate having a good balance of radiation resistance, transparency, heat resistance, and heat formability, and a package formed by molding the same. And

[Means for solving problems]

The present invention has been made to achieve the above objects, and the gist thereof is to add 100 parts by weight of an ethylene-propylene random copolymer having an ethylene content of 2 to 8% to an organic peroxide of 0.005 to 0.
A layer (layer A) composed of a composition in which 1 part by weight and 0.01 to 0.3 parts by weight of a triallyl (iso) phthalate or (iso) cyanuric acid derivative are blended, an ethylene-propylene block copolymer 95 to 80%, and ethylene and carbon. Number 4-12
A laminate having at least one layer consisting of a composition obtained by blending 5 to 20% of a copolymer with an α-olefin (B layer), or having at least one layer of the above A layer and B layer,
Furthermore, it is a laminate in which a layer (C layer) made of one or more thermoplastic resins is laminated.

[Specific Configuration and Action of the Invention]

The ethylene content of the layer A constituting the laminate of the present invention is 2
A polypropylene-based composition is prepared by mixing 0.005 to 0.1 part by weight of an organic peroxide and 0.01 to 0.3 part by weight of a triallyl (iso) phthalate or (iso) cyanuric acid derivative in an ethylene-propylene random copolymer of -8%.

If the ethylene content in the ethylene-propylene random copolymer is less than 2%, the radiation resistance decreases, and if it exceeds 8%, the strength and heat resistance decrease.

The organic peroxide is selected from those having a decomposition rate at the melting point of the ethylene-propylene random copolymer as a half-life longer than 1 second and a decomposition rate at 300 ° C. as a half-life shorter than 10 minutes. Of the above organic peroxides such as hydroperoxides, alkylperoxides, acylperoxides, ketone peroxides, alkylperesters, peroxycarbonates and silicon peroxides, the above decomposition rate is preferable. With t-butyl hydroperoxide,
Dicumyl peroxide, 1,3-bis (t-butylper)
(Oxyisopropyl) benzene, benzoylperoxide, methylisobutylketone peroxide, t-butylperbenzoate, vinyltris (t-butylperoxide)
(Oxy) silane and the like.

The amount of these organic peroxides used is 0.005 to 0.1 part by weight based on 100 parts by weight of the ethylene-propylene random copolymer. If the amount used is less than 0.005 parts by weight, deterioration of radiation resistance over time cannot be suppressed, and if it exceeds 0.1 parts by weight, molecular cleavage is severe and extrusion molding becomes difficult.

As the modifier used in combination with the organic peroxide, diallyl (iso) phthalate or (iso) cyanuric acid derivative is used, and as the (iso) cyanuric acid derivative, triallyl (iso) cyanurate, tris (acrolein) is used. Iloxyethyl) isocyanurate, tris (methacryloyloxyethyl) isocyanurate, bis (acryloyloxyethyl) 2-hydroxyethyl isocyanurate, trimethallyl isocyanurate, tris (2,3
-Epoxypropyl) isocyanurate and the like. The usage-amount is 0.01-0.3 weight part with respect to 100 weight part of ethylene-propylene random copolymers. That amount
If it is less than 0.01 part by weight, the effect is poor, and the resin is deteriorated after irradiation with radiation to lower the tensile elongation. If it exceeds 0.3 part by weight, the tensile elongation is reduced due to an increase in the radiation-crosslinked portion.

In addition, the B layer is an ethylene-propylene block copolymer 95
-80%, and a blend of 5 to 20% of a copolymer of ethylene and an α-olefin having 4 to 12 carbon atoms, and when the blending ratio is out of the above range, radiation resistance, heat shaping property, Transparency decreases.

Melt index (MFR, JIS-K-67) of the above blended composition
The load of 2.16 Kg and the temperature of 230 ° C. is not particularly limited by 58, and is selected depending on the molding method, but in the extrusion molding, the range of 0.1 to 50 is suitable.

Examples of the ethylene-α4 olefin copolymer having 4 to 12 carbon atoms include ethylene-butene-1 copolymer, ethylene-4-methylpentene-1 copolymer and ethylene-hexene-1 copolymer. can give. However, in view of transparency, radiation resistance, rigidity, etc. when blended with an ethylene-propylene block copolymer, ethylene-
Butene-1 copolymer, ethylene-4-methylpentene-
1-copolymer and ethylene-hexene-1 copolymer are preferred.

These ethylene-α-olefin copolymers are obtained by polymerizing ethylene and at least one α-olefin in the presence of a catalyst by a medium-low pressure method or a high-pressure method.

The blended material that constitutes each of the A layer and the B layer may be blended, melted, extruded, granulated, and then subjected to molding, or may be dry-blended before molding and then subjected to molding. Good.

In addition, the raw materials for forming the A layer and the B layer include commonly used additives such as antioxidants, clarifiers, nucleating agents, UV absorbers, lubricants, antistatic agents, antiblocking agents,
A dispersant such as metallic soap and a neutralizing agent may be added and used.

In order to form the laminate, the A layer and the B layer are extruded to a predetermined thickness and laminated by an ordinary apparatus such as a T-die forming machine.

In this case, the thickness of the layer A is preferably in the range of 1 to 50%, particularly 10 to 40% of the total thickness of the laminate. The thickness of layer A is 1
If it is less than%, the transparency may be poor and the heat seal strength may be insufficient. Further, if the thickness of the layer A exceeds 50%, it tends to adhere to the mold during heat shaping such as deep drawing, and the mold releasability deteriorates.

That is, the layer A in the present invention is used as a transparent heat seal layer and as an improvement in the transparency of the layer B. Also,
The presence of the B layer can improve the heat shaping property, and
Heat shaping is difficult with the layer alone, and transparency and heat sealability are poor with the layer B alone. Therefore layers A and B
The presence of layers is essential, and by stacking layers A and B,
It is possible to obtain a laminate exhibiting each property, excellent in radiation resistance, and excellent in heat sealability, heat shaping property, and transparency. Further, a laminated body of A layer, B layer, A layer or B layer, A layer, B layer is also effective.

However, a layer (C
By stacking layers), pinhole property, heat resistance,
The decorativeness, rigidity, transparency, and heat shaping property are improved, and it is extremely effective especially for improving the heat shaping property.

Polyamide or polyethylene terephthalate is used as the thermoplastic resin used in the C layer.

The thermoplastic resin is laminated on the A layer side or the B layer side.
As a lamination method, a dry lamination adhesive such as a polyurethane-based or polyacrylic-based adhesive is used, and a known dry lamination method or sand lamination method is used, or co-extrusion is performed.

Even when these three layers A, B, and C are laminated, the thickness of the A layer is preferably 1 to 50% of the sum of the A layer and the B layer, and particularly preferably 10 to 40%.

By molding the laminated body consisting of three layers of A, B and C into various shapes by a well-known vacuum forming method or the like,
The package excellent in radiation resistance of the present invention can be obtained.

〔Example〕

Pellets of the following formulation were made to form layers A and B.

To 100 parts by weight of an ethylene-propylene random copolymer having an ethylene content of 2 to 8%, tetrakis [methylene (3,5-di-t-butyl-hydroxyphenyl)] was added as an additive.
Propionate] 0.05 part by weight of methane, 0.05 part by weight of calcium stearate, 0.35 part by weight of synthetic silica, 0.08 part by weight of erucic acid amide 0.08 part by weight and mixed well, then 40 mmφ
Extruded at 220 ° C. with an extruder to obtain pellets for layer A.

Also, MFR (value measured at 230 ° C according to JIS-K-6758,
The same shall apply hereinafter) is 1.0 and an ethylene-propylene block copolymer having a rubber content of 19% has an MI (value measured at 190 ° C according to JIS-K-6760) of 14 ethylene-butene-1 copolymer (density 0.920). Was added and mixed, then 220 ° C with a 40 mmφ extruder.
Was extruded into pellets for layer B.

Examples 1 to 5 Comparative Examples 1 to 3 Using the above pellets, the pellets for layer A used as the organic peroxide were 2.5-dimethyl-2.5-di (t-butylperoxy) hexane (hereinafter referred to as [a]. ), Or dibutyl peroxide (hereinafter referred to as [B]), and a modifier such as diallyl phthalate (DAP) or triallyl isocyanurate (TAIC) in various proportions by dry blending, and various proportions of pellets for layer B. A two-layer, two-layer film was molded together with the pellets of 1. by a T-die molding machine at 250 ° C. to form a film having a thickness of 50 μm. This film was irradiated with γ-rays at 3 Mrad with a cobalt 60 radiation source to evaluate radiation resistance. Table 1 shows the results of the laminate used and the radiation resistance.

The breaking strength and tensile elongation in the table were measured according to JIS-Z-1702, and the impact resistance strength was measured with a pendulum type 1/2 inch hemisphere.

Example 6 A polyamide having a thickness of 40 μm (manufactured by Toray Synthetic Film Co., Ltd., Rayfan No. type T- 1401)
As a C layer, a urethane-based adhesive (Toyo Morton Co., Ltd., Ard coat, main agent AD-300A, curing agent AD-300B, solvent
BTS-500 mixed at a ratio of 100: 100: 116), using a laminator, adhesive application amount 4.1g / m ² , laminating pressure 5.0Kg / cm ² , heating roll temperature 65 ° C, drying Temperature 90-110
Dry lamination under conditions of ℃ and speed of 20m / min.
A stack of B / C layers with a thickness of 90 μm was made, and a vacuum forming machine (FLX047 manufactured by Asano Seisakusho) was used, and the upper heater temperature was 30.
0 ° C, lower heater temperature 250 ° C, time 10 _sec , aperture depth 20 mm
Using a mold at a temperature of 30 ° C, the drawability of the drawing, adhesion to the mold, and mold collapse were observed. The results are shown in Table 2.

[Effect] As described above, the laminate according to the present invention and the package formed by molding the laminate have excellent radiation resistance, good drawability, transparency, and a certain temperature. Endures,
Since it can be heat-sealed, it can be packaged with a medical device such as a syringe and can be sterilized by radiation and can be used for a timely use. Therefore, it has many advantages such as a marked increase in treatment efficiency.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP 62-3950 (JP, A) JP 62-3951 (JP, A) JP 61-73711 (JP, A)

Claims (2)

[Claims] 1. An organic peroxide is added to 100 parts by weight of an ethylene-propylene random copolymer having an ethylene content of 2 to 8% by weight.
A layer composed of a composition containing 0.005 to 0.1 part by weight and 0.01 to 0.3 part by weight of a triallyl (iso) phthalate or (iso) cyanuric acid derivative (hereinafter referred to as layer A), and an ethylene-propylene block copolymer 95 to 80 wt. %, And a layer (hereinafter, referred to as B layer) made of a composition obtained by blending 5 to 20 wt% of a copolymer of ethylene and an α-olefin having 4 to 12 carbon atoms, and an A layer. Is 1 to 50% of the total thickness of the laminate, and the radiation resistant laminate has excellent heat formability. 2. 100 parts by weight of an ethylene-propylene random copolymer having an ethylene content of 2 to 8 wt% and an organic peroxide
A layer (A layer) comprising a composition in which 0.005 to 0.1 part by weight and 0.01 to 0.3 part by weight of a triallyl (iso) phthalate or (iso) cyanuric acid derivative are blended, an ethylene-propylene block copolymer 95 to 80 wt%, and Copolymer of ethylene and α-olefin having 4 to 12 carbon atoms 5 to 20 wt%
At least one layer made of a composition obtained by blending (B layer) and one layer made of polyamide or polyethylene terephthalate (hereinafter referred to as C layer), and the thickness of the A layer is the same as the thickness of the A layer and the B layer. A radiation resistant package formed by molding a laminate that is 1 to 50% of the sum.