JP2001261866A - Polypropylene molding and vacuum blood-gathering tube prepared therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polypropylene molding which has gas barrier properties to water vapor, oxygen, carbon dioxide and the like and non-adsorptivities to low-molecular organic compounds, is excellent in recycling properties and moldability, and can be used widely, and a vacuum blood-gathering tube prepared therefrom. SOLUTION: There are provide a polypropylene molding prepared by forming a ceramic thin film layer, by a plasma chemical vapor deposition(CVD) process, on either the inner or outer surface or on both the surfaces of a plastic molded article comprising an ethylene-polypropylene random copolymer, and a vacuum blood-gathering tube prepared therefrom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a plastic molded article made of a polypropylene resin, for example, an injection molded article, a blow molded article, a molded article of a variety of shapes such as a film, by using silicon oxide by a plasma chemical vapor deposition (CVD) method. The present invention relates to a molded polypropylene article having a thin film layer as a component, and a polypropylene molded article having good adhesion of a thin film to a molded article, excellent gas barrier properties, and non-adsorption to low molecular organic compounds. In particular, it is suitably used for vacuum blood collection tubes and the like.

[0002]

2. Description of the Related Art Recently, plastic containers made of polypropylene resin have been widely used as packaging containers in various fields such as foods and pharmaceuticals because of their ease of molding, light weight, and low cost. ing. However, the container has a problem that it permeates low molecular gas such as oxygen and carbon dioxide and adsorbs low molecular organic compounds.

[0003] Various measures have been taken to solve the above problems. For example, as one method of reducing gas permeability, there is a method of laminating or blending a plurality of plastic materials. In these methods, gas permeability can be reduced to some extent, but as a container in which higher gas barrier properties are required,
There are problems such as a lack of gas barrier properties and an increase in material cost due to the compounding of different materials, and the container has not been practically used. Furthermore, due to recent environmental impact measures, these plastic containers have a problem that it is difficult to reuse such as recycling because of the composite of different materials. As another example, in order to improve the gas barrier property, insert molding of a film having a high gas barrier property is performed, but this method requires a complicated forming process and increases the manufacturing cost. There are problems such as problems and restrictions on the shape that can be formed.

On the other hand, a technique is known in which the surface of a plastic container is coated with a thin film by using a plasma enhanced chemical vapor deposition (CVD) method. In most cases, the technique of coating a thin film on the surface of a container by the CVD method is applied to a polyethylene terephthalate resin.
Polyethylene terephthalate resin is excellent in transparency, but has a problem that its use is limited due to properties such as moldability.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a gas barrier property against water vapor, oxygen, carbon dioxide, etc. and a non-adsorbing property against low molecular weight organic compounds. An object of the present invention is to provide a versatile polypropylene molded article having excellent properties and a vacuum blood collection tube using the same.

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to a method for forming a plasma on an inner surface or an outer surface of a plastic molded article comprising an ethylene-polypropylene random copolymer. A polypropylene molded article having a ceramic thin film layer formed by a chemical vapor deposition (CVD) method.

Further, according to a second aspect of the present invention, in the polypropylene molded article according to the first aspect, the ethylene content of the ethylene-polypropylene random copolymer is 1%.
% Or more.

According to a third aspect of the present invention, there is provided a molded polypropylene article according to the first or second aspect, wherein a ratio of a weight average molecular weight (Mw) to a number average molecular weight (Mn) of the ethylene-polypropylene random copolymer is obtained. (Mw / M
n) is 2.7 or less.

[0009] The invention described in claim 4 is the first invention.
3. The polypropylene molded article according to any one of the items 3, wherein the crystallinity of the plastic molded article is 50% or less.

[0010] The invention according to claim 5 provides the invention according to claims 1 to 5.
5. The polypropylene molded article according to any one of items 4, wherein the ethylene-polypropylene random copolymer contains a crystal nucleating agent.

The invention according to claim 6 is characterized in that the nucleating agent according to claim 5 is an organic phosphate-based or sorbitol-based nucleating agent.

The invention according to claim 7 is the first invention.
7. The polypropylene molded article according to any one of items 6, wherein the ethylene-polypropylene random copolymer is an ethylene-polypropylene random copolymer polymerized by a metallocene catalyst.

[0013] The invention described in claim 8 is the first invention.
8. The polypropylene molded article according to any one of items 7, wherein the ceramic thin film is a thin film containing silicon oxide as a main component.

The ninth aspect of the present invention is the first aspect of the present invention.
A vacuum blood collection tube, characterized by using a polypropylene molded article comprising the ethylene-polypropylene random copolymer according to any one of items 9 to 9.

[0015]

Embodiments of the present invention will be described below in detail. The polypropylene molded article of the present invention,
A ceramic thin film layer is formed by a plasma chemical vapor deposition (CVD) method on either or both inner and outer surfaces of a plastic molded article made of an ethylene-polypropylene random copolymer.

In the present invention, plasma enhanced chemical vapor deposition (CV)
The ceramic thin film formed by the method D) contains silicon oxide as a main component, and the following compounds are used as a raw material for vapor deposition. As monomers, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane,
Vinyltrimethylsilane, methyltrimethoxysilane,
Hexamethyldisiloxane, methylsilane, dimethylsilane, trimethylsilane, diethylsilane, propylsilane, phenylsilane, vinyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, Octamethylcyclotetrasiloxane and the like can be mentioned.

Oxygen, carbon dioxide or the like is further used as a reaction gas in addition to the vapor deposition material selected from the above compounds. Further, argon, helium, or the like may be used as a carrier gas.

As a combination of a deposition material selected from the above compounds and a reactive gas, it is preferable to use a mixture of hexamethyldisiloxane and oxygen gas.

The polypropylene resin used in the present invention comprises an ethylene-polypropylene random copolymer, and is an ethylene-polypropylene random copolymer having an ethylene content of 1% or more. When the ethylene content is 1% or more, the crystallinity of the copolymer is reduced, and the thin film is easily formed by plasma enhanced chemical vapor deposition (CVD). In particular, an ethylene-propylene random copolymer polymerized using a metallocene catalyst is preferable.

The molecular weight distribution of the ethylene-polypropylene random copolymer used in the present invention is such that the ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) is 2.7 or less. A distribution is preferred.

Further, the crystallinity of the molded article of the present invention comprising the copolymer is preferably 50% or less. Crystals with relatively large particles, such as spherulites, hinder the formation of a uniform film by plasma-enhanced chemical vapor deposition. The uniform distribution in the polypropylene resin allows a uniform film to be formed on the polypropylene molded article by plasma enhanced chemical vapor deposition.
As this nucleating agent, it is preferable to use an organic phosphate-based or sorbitol-based nucleating agent, but it is not particularly limited thereto.

In the present invention, molded articles made of the copolymer include injection molded articles such as food cups, container caps, medical tools and the like, blow molded articles such as bottles, vacuum molded articles such as trays, films and the like. However, it is not limited to this as long as it can be molded.

The polypropylene molded article comprising the ethylene-polypropylene random copolymer of the present invention may be provided with a ceramic thin film layer on either or both of the inner and outer surfaces of the molded article according to the required quality depending on the application. Can be. The thickness of the ceramic thin film is 10 to 200 n
m is preferred, but not limited thereto.

The molded article made of the ethylene-polypropylene random copolymer provided with the ceramic thin film layer of the present invention is suitably used for a vacuum blood collection tube made of an ethylene-polypropylene random copolymer blood collection tube. Vacuum blood collection tubes are required to have high gas barrier properties and not to adsorb low molecular weight organic compounds and must not be eluted in the contents. A polypropylene molded article comprising the ethylene-polypropylene random copolymer of the present invention,
Since it has high gas barrier properties and excellent non-adsorbing properties for low molecular organic compounds, it is suitably used for vacuum blood collection tubes and the like.

[0025]

EXAMPLES Examples of the polypropylene molded article comprising the ethylene-polypropylene random copolymer of the present invention will be specifically described below.

Example 1 Using a polypropylene resin having an ethylene content of 4% and a weight-average molecular weight-to-number average molecular weight ratio (Mw / Mn) of 2.3 in an ethylene-propylene random copolymer. A food cup (φ75 mm) was injection molded. Its crystallinity was measured by the density method shown below to be 40%. A ceramic thin film containing silicon oxide as a main component was laminated on the inner surface of the molded article by a plasma chemical vapor deposition (CVD) method using a gas obtained by mixing hexamethyldisiloxane and oxygen. When the oxygen barrier of the molded article was measured by the Mocon method using a Mocon Oxitran 10 / 50A measuring device, it was 0.100 fmol / (pkg ·
s · Pa). [Density method] The density was measured with an Acubic 1330 dry densitometer manufactured by Shimadzu Corporation, and the crystallinity was determined by the following equation. Crystallinity (%) = (d-da) / (dc-da) * (dc
/ D) * 100 d: density of the measured value of the sample da: density of completely amorphous (set to 0.850) dc: density of perfect crystal (set to 0.936)

Example 2 Using a polypropylene resin having an ethylene content of 8% in an ethylene-propylene random copolymer and a ratio (Mw / Mn) of weight average molecular weight to number average molecular weight of 2.7. A food cup (φ75 mm) was injection molded. When the crystallinity is measured by the density method, 3
2%. Plasma chemical vapor deposition (CVD) on the molded product
A ceramic thin film containing silicon oxide as a main component was laminated on the inner surface of the molded product using a gas obtained by mixing hexamethyldisiloxane and oxygen by a method. When the oxygen barrier of the molded article was measured by the Mocon method, it was 0.080 fmol / (pkg · s · Pa
)Met.

Example 3 The ethylene-propylene random copolymer had an ethylene content of 2%, a ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) of 2.2, and
A food cup (φ75 mm) was injection molded using a polypropylene resin to which a sorbitol crystal nucleating agent was added. Its crystallinity measured by a density method was 42%. A ceramic thin film containing silicon oxide as a main component was laminated on the inner surface of the molded article by a plasma chemical vapor deposition (CVD) method using a gas obtained by mixing hexamethyldisiloxane and oxygen. The oxygen barrier of the molded article measured by the Mocon method was 0.085 fmol / (pkg · s · Pa).

Example 4 Using a polypropylene resin in which the ethylene content of the ethylene-propylene random copolymer is 4% and the ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight is 2.3. A vacuum blood collection tube (for 10 cc) was injection molded. When the crystallinity is measured by a density method, it is 40.
%Met. A ceramic thin film containing silicon oxide as a main component was laminated on the inner surface of the molded article by plasma chemical vapor deposition (CVD) using a gas obtained by mixing hexamethyldisiloxane and oxygen. When the oxygen barrier of the molded article was measured by the Mocon method, it was 0.040 fmol / (pkg · s · Pa
)Met. On the other hand, for comparison, the case where the ceramic thin film was not laminated was 0.375 fmol / (pkg ·
s · Pa).

Example 5 For a foodstuff, a polypropylene resin having an ethylene content of 4% in an ethylene-propylene random copolymer and a ratio (Mw / Mn) of a weight average molecular weight to a number average molecular weight of 5 was used. A cup (φ75 mm) was injection molded. When its crystallinity is measured by the density method, it is 43%.
Met. A ceramic thin film containing silicon oxide as a main component was laminated on the inner surface of the molded article by a plasma chemical vapor deposition (CVD) method using a gas obtained by mixing hexamethyldisiloxane and oxygen. The oxygen barrier of the molded article measured by the Mocon method was 0.300 fmol / (pkg · s · Pa).

<Example 6> A polypropylene having an ethylene content of 4% in the ethylene-propylene random copolymer and a ratio (Mw / Mn) of weight-average molecular weight to number-average molecular weight of 3.1 was used for food. A cup (φ75 mm) was injection molded. Its crystallinity measured by a density method was 55%. A ceramic thin film containing silicon oxide as a main component was laminated on the inner surface of the molded article by a plasma chemical vapor deposition (CVD) method using a gas obtained by mixing hexamethyldisiloxane and oxygen. The oxygen barrier of the molded article measured by the Mocon method was 0.250 fmol / (pkg · s · Pa).

Comparative Example 1 A food cup (φ75 mm) was injection molded using a homo-polypropylene resin. Its crystallinity measured by a density method was 60%. A ceramic thin film containing silicon oxide as a main component was laminated on the inner surface of the molded article by a plasma chemical vapor deposition (CVD) method using a gas obtained by mixing hexamethyldisiloxane and oxygen.
When the oxygen barrier of the molded article was measured by the Mocon method, it was 1.05.
It was 0 fmol / (pkg · s · Pa).

Comparative Example 2 Using a polypropylene resin having an ethylene content of 5% in the ethylene-propylene block copolymer and a ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight of 2.8. A food cup (φ75 mm) was injection molded. When the crystallinity is measured by the density method, 4
7%. Plasma chemical vapor deposition (CVD) on the molded product
A ceramic thin film containing silicon oxide as a main component was laminated on the inner surface of the molded product using a gas obtained by mixing hexamethyldisiloxane and oxygen by a method. When the oxygen barrier of the molded article was measured by the Mocon method, it was 0.980 fmol / (pkg · s · Pa
)Met.

[0034]

The polypropylene molded article of the present invention is made of an ethylene-polypropylene random copolymer and has a ceramic thin film layer containing silicon oxide as a main component. Non-adsorbent for low molecular organic compounds,
No elution of low molecular compounds such as acetoaldehyde,
It has become possible to provide a versatile molded body having excellent recyclability. As a polypropylene resin, a thin film containing silicon oxide as a main component is formed on a molded body made of an ethylene-polypropylene random copolymer having an ethylene content of 1% or more by a CVD method to obtain 0.5 fmol /
An oxygen barrier property of less than (pkg · s · Pa) could be obtained. The ratio between the weight average molecular weight and the number average molecular weight of the ethylene-polypropylene random copolymer is 2.7.
The oxygen barrier property of less than 0.1 fmol / (pkg · s · Pa) was able to be obtained by setting the crystallinity of the following and the molded body to 50% or less. Further, the polypropylene molded article of the present invention can be used in various fields such as a food field and a pharmaceutical field as molded articles of various shapes such as injection molded articles, blow molded articles and films. In particular, it is suitably used for a vacuum blood collection tube or the like, which is required to have high gas barrier properties and non-adsorptivity, made of a polypropylene blood collection tube.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Wataru Iijima 1-5-1 Taito, Taito-ku, Tokyo Inside Toppan Printing Co., Ltd. (72) Inventor Yasushi Yamamoto 1-1-5-1 Taito, Taito-ku, Tokyo F-term (reference) in Toppan Printing Co., Ltd. 4F006 AA12 AA56 AB39 AB76 BA05 BA11 CA07 CA09 DA01 4J002 BB151 EC056 EW036 FD206 GB01 GG01 4K030 AA06 AA09 AA14 AA16 BA44 CA07 CA15 CA16 FA01 LA11

Claims (9)

[Claims] 1. A polypropylene, wherein a ceramic thin film layer is formed by a plasma chemical vapor deposition (CVD) method on either or both of an inner surface and an outer surface of a plastic molded article made of an ethylene-polypropylene random copolymer. Molded body. 2. The molded polypropylene article according to claim 1, wherein the ethylene content of the ethylene-polypropylene random copolymer is 1% or more. 3. A weight average molecular weight (Mw) and a number average molecular weight (Mw) of the ethylene-polypropylene random copolymer.
The polypropylene molded article according to claim 1 or 2, wherein the ratio (Mw / Mn) to n) is 2.7 or less. 4. The plastic molded product has a crystallinity of 5
The polypropylene molded product according to any one of claims 1 to 3, wherein the content is 0% or less. 5. The polypropylene molded article according to claim 1, wherein the ethylene-polypropylene random copolymer contains a nucleating agent. 6. A molded polypropylene article, wherein the nucleating agent according to claim 5 is an organic phosphate-based or sorbitol-based nucleating agent. 7. The ethylene-polypropylene random copolymer according to claim 1, wherein said ethylene-polypropylene random copolymer is an ethylene-polypropylene polymerized with a metallocene catalyst.
The polypropylene molded article according to any one of claims 1 to 6, which is a polypropylene random copolymer. 8. The molded polypropylene article according to claim 1, wherein said ceramic thin film is a thin film containing silicon oxide as a main component. 9. A vacuum blood collection tube using a polypropylene molded article comprising the ethylene-polypropylene random copolymer according to any one of claims 1 to 9.