JPS6155142A - Synthetic resin molding - Google Patents

Abstract

PURPOSE:A nontoxic synthetic resin molding excellent in flexibility, transparency, heat resistance, etc., and suitable for blood bags, food packaging materials, etc., obtained by using a resin mixture of a specified composition as a raw material and molding it into a sheet with one smooth surface and another roughened surface. CONSTITUTION:A resin mixture is formed by mixing 30-90wt% block copolymer composed of end blocks comprising a polymer of an aromatic vinyl compound, amounting to 10-40wt% of the copolymer and being hydrogenated to at most 10% and an intermediate block comprising a polymer of a conjugated diene and being hydrogenated to at least 90% with 5-40wt% isotactic polypropylene of an m.p. >=150 deg.C and 5-40wt% ethylene/acrylate copolymer of an acrylate content >=5% or ethylene/vinyl ester copolymer of a vinyl ester content >=5%. This resin mixture is molded into a sheet with one smooth surface and another roughened surface having a surface roughness as stipulated in JIS of 6-18S.

Description

Detailed Description of the Invention B) Object of the Invention (Field of Industrial Application) The present invention relates to a synthetic resin molded article. More specifically, the present invention relates to a non-toxic synthetic resin molded article that has excellent blocking properties, transparency, and high-temperature strength.

(Prior Art) Various molding resin compositions have been proposed and put into practical use for producing transparent and flexible molded products in the fields of food packaging materials, medical instruments, and the like.

For example, resin compositions and molded products using soft polyvinyl chloride have excellent flexibility and transparency, and have a tensile strength of 200K).
/d, maintains its shape even at high temperatures of about 120"C, and has sufficient strength, so it can be sterilized at high temperatures, and is used not only in the general packaging industry, but also in food packaging,
It is also widely used in medical equipment, etc. However, since soft polyvinyl chloride usually contains a large amount of plasticizer, the plasticizer gradually evaporates and hardens, causing the contents to deteriorate, especially in packaging bags, tubes, etc. made from sheet-shaped molded products. Plasticizer may migrate and cause hygiene problems.

In addition, unless the amount of chloride and nil monomers remaining in the molded product was extremely reduced, there was a risk of hygienic problems.

In this regard, block polymers such as styrene-butadiene-styrene block copolymers, and isobrene-butadiene copolymers are available as molding resin compositions that do not contain plasticizers and have various physical properties such as transparency and flexibility. A mixed resin based on a hydrogenated block copolymer obtained by further hydrogenating the hydrogenated block copolymer and blended with polypropylene and an ethylene-vinyl acetate copolymer resin, and a mixed resin based on the above-mentioned hydrogenated block copolymers and blended with polypropylene and ethylene-vinyl acetate copolymer resin. A mixed resin containing ethylene acrylate has been proposed (Japanese Unexamined Patent Publication No. 54-88950,
JP-A-59-74158) 0 (Problems to be Solved by the Invention) The above mixed resin using the hydrogenated block copolymer, polypropylene and ethylene-vinyl acetate copolymer or ethylene acrylate can be used in various ways as described above. Useful for applications. However, if such resin is used as a sheet or bag-like material, fc
a. It had the disadvantage of easily causing blocking.

In particular, bag-like items have a problem in that the inner surface is blocked and cannot be used as a bag. To prevent such blocking, a small amount of powdered lubricant or talc is sprinkled on the surface of the sheet immediately after production, or an anti-blocking agent (high melting point wax, amide derivative of long chain fatty acid, metal soap, etc.) There is a method Q4 to make a sheet using a compounded material, but the former is difficult to spread uniformly and is unhygienic as foreign matter adheres to the sheet surface, and the latter is unsanitary because the compounded agent is on the sheet surface after forming. All of the products released had problems in terms of the working environment and changes in the chemicals over time due to long-term neglect and storage.

The present invention aims to provide a synthetic resin sheet and a bag-shaped molded product thereof that solve the above-mentioned problems.

(b) Structure of the Invention Thus, according to the present invention, 1. (a) Both end blocks of a block copolymer consisting of both end blocks made of a polymer of an aromatic vinyl compound and an intermediate block made of a conjugated diene polymer are (10 to 40% by weight of the copolymer, less than 10% of which is hydrogenated)
, and a block copolymer in which 90% or more of the intermediate block is hydrogenated 80% to 90% by weight fX.

(b) Isotactic polypropylene with a melting point of 150°C or higher or a copolymer containing it as a main component: S lif&
X to 40% by weight, and (0) an ethylene-acrylate copolymer with an acrylate content of 5% or more or an ethylene-vinyl ester copolymer with a vinyl ester content of 5% or more: a mixed resin consisting of 6% to 40% by weight. A synthetic resin molded body is provided as a material, and has a sheet surface with one side having a smooth surface and the other side having a rough surface having a JIS standard surface roughness of 68 to 188. .

First, a mixed resin serving as a base resin forming the synthetic resin molded article of the present invention will be explained.

Component (a) consists of an intermediate block (90 to 60% by weight) made of a conjugated diene polymer and both end blocks (10 to 40% by weight) made of an aromatic vinyl compound polymer at both ends thereof.
This is a hydrogenated block copolymer obtained by hydrogenating a block copolymer consisting of

Polymers of aromatic vinyl compounds constituting the above-mentioned both end blocks include styrenic polymers such as polystyrene, poly-α-methylstyrene, poly-α-methylstyrene, and polychlorostyrene, but their molecular weights are An average molecular weight of ms, ooo to 125,000 is suitable, and polystyrene is most preferred. On the other hand, conjugated diene polymers constituting the intermediate block include polybutadiene, polyisoprene, polychloroprene, etc.
The molecular weight is t o, o o as the number average molecular weight.
o to a o o, o o o are suitable, with polybutadiene and polyisoprene being particularly preferred.

By hydrogenating the above block copolymer,
p A block copolymer used in the present invention is obtained.

In this case, it is necessary that the hydrogenation ratio of both end blocks is 10% or less, and the hydrogenation ratio of the middle block is 90% or more. In particular, the hydrogenation ratio of the intermediate block is preferably 95% or more. Here, the hydrogenation ratio refers to the ratio of bonds that are actually hydrogenated among double bonds that can be hydrogenated. This means that, for example, if the intermediate block is polybutadiene, the hydrogenated product will have an ethylene-butylene copolymer structure, and if the intermediate block is polyisoprene, the hydrogenated product will have an ethylene-propylene copolymer structure as a whole. Heat resistance as
This improves weather resistance, and particularly leads to excellent heat resistance (high temperature strength) of the molded article of the present invention. Note that it is preferable that the weight of each end block is 15 to 25%.

The block copolymer used in the present invention is Kraton AT6
50. Clayton G-1652, Clayton G-165
7% Kraton G-1658 (all manufactured by Shell Chemical), etc., and is easily available. Furthermore, these block copolymers may be used not only alone, but also in combination of two or more.

or a copolymer mainly composed of it, which is generally used as a molding material, can be used as is.

As the copolymer, block copolymers and random copolymers of propylene and α-olefins such as ethylene and 1-butene can be used, but in order to maintain the flexibility of the composition of the present invention, flexible copolymers are preferred, and particularly Random copolymers are crowded.

Next, it is necessary that the ethylene-acrylate copolymer as component (c) used in the present invention has an acrylate content of 5% or more. If the acrylate content is less than 5%, the transparency of the composition itself will decrease and the flexibility of the composition will be insufficient. Acrylates used in the ethylene-acrylate copolymer used in the present invention include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and methacrylic acid esters corresponding to these. Most preferred are methyl acrylate and ethyl acrylate.

Moreover, an ethylene-vinyl ester copolymer having a vinyl ester content of 52 g or more can also be used as component (0). Examples of the vinyl ester in such an ethylene-vinyl ester copolymer include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl stearate, but vinyl acetate is most preferred. The maximum content of these acrylates or vinyl esters in the copolymer is not particularly limited, but is suitably up to about 30%. Note that it is preferable to use an ethylene-7 acrylate copolymer from the viewpoint of low temperature flexibility, high temperature strength, stability, etc.

This invention is most characterized in that it is made of the above-mentioned mixed resin and has one side roughened. Such surface roughness is JI
The maximum height specified by SBO601 (Rma) is in the range of 68 to 188 as described above. This has a maximum height of over 6μη and 18μm.
Indicates that: The preferred range is 88N128. If it is less than 68, the transparency of the synthetic resin molded product will be good, but the blocking property will be poor, and if it exceeds 188, the blocking property will be good, but the transparency of the synthetic resin molded product will be poor. From this point of view, the above range of surface roughness is an appropriate range that provides both transparency and blocking properties.

When a synthetic resin molded body having such surface roughness is made into a sheet, it can be produced, for example, using a sheet manufacturing apparatus as shown in FIG. First, the mixed resin in solid form (pellets or powder) is heated and melted in an extruder (1).
The melt is extruded from a sheet die (2) as a substantially sheet-like molded product, and rolled into a sheet with a thickness of ii with a silicone rubber roll (3) and a metal roll (4). ) to form a specific range of surface roughness on the sheet surface on the roll side, then pass through take-up rolls (5) and (6), and then take the produced sheet (8) to a winder (7). Wind it up.

As mentioned above, the range of surface roughness can be easily changed by changing the silicone rubber roll. Although the surface can be roughened using a metal roll, a silicone rubber roll provides a more uniform roughening with a better appearance.

In addition to the above-mentioned essential main resin components, the mixed resin used in the present invention may contain various plasticizers and anti-blocking agents in amounts that do not impede flexibility, transparency, high-temperature strength, moldability, and safety, depending on the application. , a sealing property improver, a heat stabilizer, an antioxidant, an ultraviolet absorber, a lubricant, a crystal nucleating agent, a coloring agent, etc. can also be included.

The present invention also provides a bag-shaped molded body formed such that the rough surface of the synthetic resin molded body becomes the inner surface.

Such a bag-shaped molded body can be generally produced by a known method, except that the inner surface of the bag is formed to have the above-mentioned surface roughness. For example, the synthetic resin sheet of the present invention produced as described above is made into a desired size,
With the rough surface facing the inner surface, the desired bag-shaped molded product can be easily formed by mechanical binding, adhesive, heat sealing, or the like. Although such a bag-shaped molded product is flexible, it does not cause blocking between the inner surfaces even when the inner surfaces are in close contact with each other when a large number of layers are stacked and left before use, and does not lose transparency even after use and contains anti-blocking agents. etc.

Since there is no migration or elution, it is extremely useful as a bag-like material for medical or food use.

(Example) Next, Examples and Comparative Examples of the present invention will be described, but these are for explaining the present invention and are not intended to limit the present invention, of course.

Example 1 A blend having the following composition was mixed in a blender and then extruded in an extruder to produce pellets.

(a) Block copolymer 1) Kraton G-1652 (Shell Kagaku!! Ri 87% by weight 11) Kraton G-1657 (Shell Kagaku Exhibition) 2
(b) Polypropylene (random copolymer with a melting point of 165°C) 20ii mass% (C) Ethylene-ethyl acrylate copolymer (EEM) (Nippon Unicar's NVC-6220, f7!X containing ethyl acrylate) 28% by weight Using this pellet, a sheet having a thickness of 0.88 m/m and a surface roughness of 128 was produced using the apparatus shown in FIG. 1 under the following conditions.

Extruder...4 Q m/mφ screw..., L/D 2 g, compression ratio 4.0 die...width 560 m/m One side of the sheet thus obtained is rich in gloss, Although some blocking occurred, because one side had a roughened finish, no blocking occurred at all, and winding into a roll was possible. In addition, a bag containing distilled water was made by heat-sealing the rough surface of this sheet as the inner surface, but the bag was almost transparent (total light transmittance of 91%), making it easy to contaminate the contents and get foreign matter in. was able to be detected. In addition, when a metal roll with a roughened surface is used as a substitute for a silicone rubber roll, one side has a rough surface, but the surface is uneven and it is not possible to continuously wind a sheet with a good appearance over the entire sheet. Example 2 0 (jL) Plutsk copolymer produced by mixing the following composition in a blender and extruding it in an extruder to produce a pellet 1) Kraton G-1650 (Shell Chemical R) 88% by weight 11) Kraton G- 1657 (Shell Chemical Exhibition) 20% by weight (b) Polypropylene (random copolymer with a melting point of 165°C)! ″
22% by weight (C) Ethylene-vinyl acetate copolymer (EV) (DQDJ-1880 manufactured by Nippon Enicar, vinyl acetate content 10
%) 25% by weight Using this pellet, the thickness was 0.8% in the same manner as in Example 1.
A sheet of 5 m/m1 and a surface roughness of 8B was produced.

One side of the obtained sheet was rich in gloss and blocking occurred, but one side had a roughened finish so blocking did not occur and winding into a roll 9 was possible. In addition, a bag containing distilled water was made by heat-sealing the rough surface of this sheet as the inner surface, but the bag was almost transparent and had a total light transmittance of 89X), preventing contamination of the contents and contamination of foreign substances. could be easily detected.

Examples 8 to 6 and Comparative Examples 1 to 2 Blends having the following compositions were mixed in a blender and then extruded in an extruder to produce pellets.

(a) Block co-electronic combination 1) Kraton G-1652 (Shell Chemical Exhibition) 80% by weight 11) Kraton G-1657 (Shell Chemical Exhibition) 28% by weight (b) Polypropylene homopolymer 22% by weight (c) Ethylene- Ethyl acrylate copolymer (EEA
) (DPDJ-6182 manufactured by Nihon Gu Nika, containing 15% ethyl acrylate) 26% by weight (d) A beret containing 0.8 parts per 100 parts of lubricant resin was used, and the surface roughness was varied. Sheets with a thickness of 0.85 m/m were prepared in the same manner as in Example 1.The blocking properties of the rough surfaces of these sheets and the total light transmittance of bags containing distilled water were prepared by heat-sealing with the rough surfaces inside. was measured. The results are shown in Table 1.

1st! ! In Comparative Example 1, the rough surface was dense, so the total light transmittance was excellent, but the blocking property was poor, and roll winding was completely impossible. Further, in Comparative Example 2, since the rough spaces were rough, no blocking occurred at all, but the total light transmittance was unsatisfactory due to diffuse reflection on the rough surface.

One side of the sheets of Examples 8 to 6 had high gloss and some blocking occurred, but each side had a roughened finish, so no blocking occurred at all, and winding into a roll was possible. However, we made bags containing distilled water by heat-sealing these sheets with the rough surface on the inside, but each bag was almost transparent with a total light transmittance of 92%), resulting in contamination of the contents. In addition, when these bags were placed under steam sterilization conditions at 121°C for 160 minutes and then taken out, the bags were slightly whitened, but the appearance remained almost unchanged and no deformation occurred. When these sheets were subjected to corona discharge treatment, silk screen printing, gravure printing, etc. could be easily performed using commercially available inks.

Comparative Example 8 A compound having the following composition was mixed in a blender and then extruded in an extruder to produce a pellet. 0 (&) block copolymer 1) Kraton G-1652 (Shell Chemical Exhibition) 40% by weight 11) Kraton G- 1657 (Shell Chemical Exhibition) 80% by weight (b) Polypropylene (random copolymer with a melting point of 165°C) 8% by weight ((1) Ethylene-ethyl acrylate copolymer (EE
human) (DPDJ-6182 manufactured by Nippon Unicar) 27% by weight Using this pellet, the thickness Q, 4
A sheet with a tri/111s surface roughness of 68 was produced.

However, the cylinder and gouey temperatures during extrusion were lowered by 10°C.

One side of the obtained sheet had a high gloss and high blocking property, and the other side had a roughened finish, so it was barely possible to wind it up into a roll.9 In addition, from this sheet, the rough surface was made the inner surface, and heat sealing was performed. When a bag containing distilled water was prepared, the bag was almost transparent. However, when the bag was taken out after being placed under steam sterilization conditions at 21° C. for 130 minutes, the bag became soft and deformed and was not suitable for practical use.

e→Effects of the Invention The synthetic resin sheet, which is one of the synthetic resin molded articles of the present invention, has excellent flexibility, transparency, and heat resistance, and does not contain any plasticizers like soft vinyl chloride. , even if it does contain a very small amount, it is an excellent product made of a specific resin that is completely safe for surgical procedures without any quality problems associated with these transfer extractions, and furthermore, one side has a surface roughness within a specific range. This is a synthetic resin sheet with significantly improved blocking properties. Furthermore, when a bag-shaped molded body made by heat-sealing such a synthetic resin sheet with the rough surface facing inside is filled with a liquid such as water, the unevenness of the rough surface is almost completely buried by the liquid. Since the container is transparent, impurities, dirt, etc. in the contents can be easily detected with the naked eye. Therefore, the bag-shaped molded article of the present invention is very excellent for use in infusion bags, nutrient solution bags, food bags for high-temperature filling of blood vessels, etc.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a sheet manufacturing apparatus showing an example of manufacturing a synthetic resin sheet according to the present invention. (1)... Extruder, (2)... Sheet die, (3
)...Silicone rubber roll, (4)...Metal roll, (5) and (6)...Take-up roll, (7)...Winder, (8)...Synthetic resin sheet.

Claims (1)

[Claims] 1. (a) Both end blocks of a block copolymer consisting of both end blocks made of a polymer of an aromatic vinyl compound and an intermediate block made of a conjugated diene polymer are 10 in the copolymer.
~40% by weight, 10% or less of which is hydrogenated, and the intermediate block is 90% or more hydrogenated: 80% to 90% by weight, (b) isoisomer with a melting point of 150°C or higher Tactical polypropylene or a copolymer mainly composed of it: 5% by weight to 40%
and (c) an ethylene-acrylate copolymer with an acrylate content of 5% or more or an ethylene-vinyl ester copolymer with a vinyl ester content of 5% or more: a mixed resin consisting of 5% to 40% by weight as a material, 1. A synthetic resin molded article, characterized in that one side is a smooth surface and the other side is a sheet surface with a rough surface having a JIS standard surface roughness in the range of 6S to 18S. 2. Block copolymer of (a): 40 to 80% by weight, (
b) isotactic polypropylene or a copolymer mainly composed thereof: 10 to 30% by weight, and (c) ethylene-acrylate copolymer or ethylene-vinyl ester copolymer: from 10 to 30% by weight A molded article according to claim 1. 3. The molded article according to claim 1 or 2, which has a surface roughness in the range of 8S to 12S. 4. The molded article according to any one of claims 1 to 8, wherein the synthetic resin molded article is a synthetic resin sheet. 5. The molded article according to any one of claims 1 to 3, wherein the synthetic resin molded article is a bag-shaped molded article configured such that the rough surface is the inner surface.