JPS6270436A - Rubber molding - Google Patents

Abstract

PURPOSE:To provide a rubber molding which has high elasticity, low gas permeability and very low compression permanent-set and is useful as a stopper for closed vessels, by irradiating a molding obtd. from an elastomer blend with a radiation to crosslink it. CONSTITUTION:2-60wt% thermoplastic resin, 20-90wt% partially crosslinked butyl rubber contg. not more than 60wt% cyclohexane-solubles and optionally 0-70wt% unvulcanized brominated butyl rubber or polyisoprene are blended to obtain an elastomer blend composed of a polymer compsn. The blend is molded, and the resulting molding is irradiated with a radiation such as gamma-rays at a dose of 0.5-3.0 Mrad of crosslink it.

Description

Detailed Description of the Invention [9] Background of the Invention 4 (Technical Field) The present invention relates to a rubber molded product. In detail, the present invention relates to a rubber molded product that has extremely low compression set and is suitable for use as, for example, a stopper for a closed container.

(Prior art) Conventionally, various closed containers, especially containers that require airtightness such as vacuum blood collection tubes, have been used as plugs to close the openings. Those made of vulcanized butyl rubber (ITR"), which has a gas permeability of 1 in 1, are widely used.

However, in the case of vulcanized butylene, there are problems such as the complexity of the vulcanized T culm, the elution of vulcanization accelerators and other chemicals, and the problem of blooming, and it is desired to develop a product to replace this. .

From this point of view, HO sulfur is required, for example, polyester elastomer [1 pyrene copolymer elastomer, polyester elastomer, The use of thermoplastic elastomers such as , S-J-Ren-isoprene block copolymer, S-91 non-butadiene block copolymer, polybutadiene, thermoplastic polyurethane, and hydrogenated 110-S J-Ren-butadiene block copolymer has been investigated. ing.

However, thermoplastic elases 1 to 1-mer have poor FjF shrinkage set compared to vulcanized rubber such as vulcanized butyl rubber, and when used as a plug, for example, the shape matches the part between the containers into which it is fitted. Permanent deformation occurs. When the container is left at a low temperature, for example -30°O, due to the difference in the coefficient of thermal expansion of the materials that make up the container and the stopper,
A gap is created between the container and the stopper, making it difficult to maintain a tight seal inside the container.

In addition, instead of the general vulcanization method, it is also possible to crosslink polymers by exposing them to radiation such as X-rays, T-rays, particle beams, etc. to give them rubber elasticity. In the case of butyl rubber polymers, the polymer decomposes when exposed to radiation q = t, so such a crosslinking method was not applicable to butyl rubber thread polymers.

TI, Pursuant to 1-1 of the invention (1) The present invention provides a novel rubber molded product.
-1 target. An object of the present invention is to provide a rubber molded product with extremely small compression set. The present invention further provides a gamma rubber molded article (v) that, when used as a closure for a sealed container, does not create a gap between the container and the closure even at low temperatures, making it suitable as a closure. [
1 target.

[1] A molded article of a 61-Las 1 hemer compound made of a polymer composition containing partially cross-linked butyl rubber was irradiated with IJ radiation to obtain a compression set of 1↓-C1 catat. Achieved from a molded product [J], which is characterized by a reformed structure.

The present invention also provides 20 to 5% of the polymer composition (components excluding inorganic components such as fillers and pigments) in the partially crosslinked rubber-lastomer formulation. The present invention further provides that the -1-lastomer formulation contains no h[1llI!
A rubber molded article is one in which 0 to 70% of the polymer composition contains chlorinated f-del rubber or unvulcanized brominated butyl rubber.

The present invention also provides that 71111
Rubber moldings containing 0 to 70% of the polymer composition of butyl rubber or polyisobutylene of jtt are prepared. The present invention also provides a molded product of partially cross-linked butyl rubber with a hexane soluble portion of 60% JX. The present invention further includes IJ and Q4-ray irradiation of 0.1~! −
), which shows a rubber molded product crosslinked with QMrad. The present invention further relates to a rubber molded article in which the radiation irradiation is carried out in air. The present invention also relates to a molded product that is a stopper for a closed container.

ITT, Specific details of the invention The present invention will be described in detail below. The rubber molded article of the present invention is made of a polymer composition containing partially crosslinked butyl rubber.
It is characterized in that the compression set is improved by crosslinking the lath l-mer compound by irradiating it with radiation. Surprisingly, butyl-based rubber, which is known to be of the radiodegradable type, has fj'
When the 04 line is illuminated on q4, the crosslinking reaction proceeds, and even if the elastomer compound contains a =6=butylgol polymer as a component other than the partially crosslinked butyl rubber, the crosslinking reaction proceeds. It is clear that the permanent compression strain of the 1st Laser 1mer will be improved by 1Q. I got it.

The partially crosslinked J-chillim contained in the 1-lastomer formulation used in the present invention is a 1-del rubber, i.e., an isobutylene-isoprene copolymer that is
For example, divinyl-based IJ is partially cross-linked using divinylbenzene, and is a good solvent for iso-1 tyrene-isoprene copolymer. 60Φ early% or less, preferably 20-5
It is cross-bridged to a certain extent by tJ so that M% in 0 is soluble. Such partially cross-linked butyl rubber 11 can be manufactured by hand, such as commercially available products such as Polyserv Plu X i, -5Q and Polyserv Dell X1-20 manufactured by Borisar.

Such "partially crosslinked butyl rubber may be used in the I-lamemilmer formulation used to contain 20 to 90% of the hand-combined composition.
%, preferably Lt 40 to E30. Straw, partially cross-linked butyl rubber is less than 20%
(If there is, there is a risk that the compression set in the elastomer compound will not be sufficiently changed because the crosslinking reaction will not proceed sufficiently when the -1-lastomer 11 compound is exposed to the Q = 1 line D4.) On the other hand, if it exceeds 90% by weight, problems arise in processability.

Components other than partially cross-linked butyl rubber of the polymer composition in the dry hemmer formulation include butyl rubber polymers, thermoplastic resins, etc., and some of these are also used in silk combinations. It is possible.

Butyl rubber-based borine includes, in addition to unvulcanized butyl rubber, polyisobutylene, unvulcanized chlorinated butyl rubber,
Unvulcanized brominated butyl rubber 4j: These may be used alone or in combination. Not yet 111
As the l1II+ butyl rubber, for example, Ikuson Butyl 065 manufactured by -1-kuson Kagaku Co., Ltd. Exon-f Del 26B, Volisar Polyservutyl 400, Poly 1J
- Butyl 402, etc., unvulcanized chlorinated butyl rubber - (4J, e.g. - L Kuson Chemical Co., Ltd. glue [11] Butyl 1066, etc., unvulcanized brominated IJ-rubber, for example, Poly+J--bu(]mobutyl×
Examples of 2nd class or rough GJ polyiso J tyrene include λ
"Kuson Kagaku Co.'s Vistanex MM1..-100,
It can be done by hand using a commercially available product such as Vistanex MMI-80. These butyl gonolytic polymers 131 and 131 are contained in the lastomer formulation in an amount of 0 to 70% by weight, preferably 0 to 40% by weight of the intermediate composition.

In addition, as thermoplastic resins (, j5, poly-1-dylene,
Borip ■ Pyrene, ]-] Blenub 1 Pyrene co-thousand combination,
Ethylene-vinyl acetate copolymer, polyester T lath
～mar, nylon king lath]・mar thread, styrene-isobrene f-”] tsuku copolymer, styrene-butadiene copolymer, polybutadiene, thermoplastic polyurethane, hydrogenated 1j11 styrene-1tazy Nimbu These thermoplastic resins can be used in combinations of 2 to 6 of the polymer composition in the Juki T-Las 1 hemer formulation.
0% by weight, preferably 5-40% by weight.

In the 1L lastomer compound used in the rubber molded product of the present invention, inorganic fillers such as mica and clay, antioxidants,
Colorants etc. are added.

The rubber molded product of the present invention (the above-mentioned components are sufficiently kneaded using a kneading machine such as a Henshil mixer or a Banbury mixer to prepare an elastomer compound in the form of pellets, etc.), and then The elastomer compound is formed into a predetermined shape by injection molding, extrusion molding, etc., and then irradiated with radiation to crosslink the elastomer compound.

The radiation used for crosslinking (1) includes electron beams, Therefore, the irradiation season t of the radiation irradiated to the elastomer compound is 0.1 to 5.0)11'ad, preferably Q, 5 to 3.0 Hrad. Zunawara 0.1
) If it is less than 1 rad, there is a risk that the crosslinking reaction will not proceed sufficiently, while if it exceeds 5.0) 1 rad, there is a risk that the elastomer compound will deteriorate.

Incidentally, the spread beam irradiation may be carried out in an inert gas or water, but it is sufficiently effective even if it is carried out in the air.

As shown in FIG. 1, the rubber molded product of the present invention is used, for example, as a stopper 4 of a vacuum blood collection tube 1. In other words, the reduced pressure blood collection tube 1 has a tubular part 2 made of crow or low gas permeable synthetic resin that is closed at the other end and is open at the other end, and a [1 old] part 3 of the tubular part 2 is sealed. The inner space of the thus sealed tubular portion 2, which is made of a punctureable plug 4 which is a rubber molded product of the present invention, is filled with a predetermined amount of waste and kept in a reduced pressure state. Since the stopper 4 has an extremely small compression set, even if the reduced pressure blood collection tube 1 is kept at a low temperature, for example, -30'C or lower, it will not interact with the shrine'd constituting the tubular part 2. Due to the difference in thermal expansion coefficient, the plug body 2 and the tubular part 4
This vacuum blood collection tube is used as follows. As shown in FIG. 1, a vacuum blood collection tube 1 filled with a predetermined gas and maintained at a predetermined vacuum polishing is closed at one end and opened at the other end as shown in FIG. Inside the blood collection tube holder 9 with the bare surface ♀1B screwed into the screw hole 7 of the end 6 [J interval [-1]
Insert the parts completely. This blood sampling needle 8 has a blood vessel piercing portion 8, for example.
a and the stopper puncture part 8b, the stopper puncture part 8bG, 1 is packaged with a rubber tip 10 made of synthetic resin or natural rubber. Next, when the blood vessel puncture part 8a of the blood collection needle 8 is passed through a blood vessel, for example, a vein 11, and the vacuum blood collection tube 1 is further pressed and inserted into the closed end 6 of the blood collection tube holder 9, the stopper puncture part 8b of the blood collection tube 8 is inserted into the rubber dep. 10 and the stopper 4 are punctured 1) so that the tip reaches the internal space 5 of the blood collection tube 1, so that the blood vessel and the internal space 5 communicate with each other. The liquid flows into the internal space 5 of the blood collection tube 1 in an amount corresponding to the degree of loaf reduction. Next, the blood vessel piercing portion 8 of the blood sampling needle 8
The bare surface ends by making a the outer dimension from the blood vessel.

The following explanation uses the case of a stopper for a vacuum blood collection tube as an example, but the rubber molded product of the present invention can also be used as a stopper for other closed containers, as a connecting member for a tubular body, or as a backing material. It is used for various purposes such as.

Hereinafter, the present invention will be explained in more detail with reference to Examples = 12
-

To Examples 1 to 4 and Comparative Example 1 to 2.
Pellets of the mixture were obtained using a sheet pelletizer at 0° C. and a sheet pelletizer at 0°C. The pellets were molded into a diameter of 29mm using a Q-1 molding machine.
It was molded into a cylindrical compression set test piece with a diameter of 0 mm and a thickness of 12.7 mm. The thus formed test piece was irradiated with T-rays using 60CO as a radiation source at a dose of 2.0 Hrad. After that, 25% according to JIS K 6301 iJ
Compression set was measured under the condition of 70'C122 hours of compression. The results are not shown in Table 1.

Example 5 Examples 1 to 4 except that the T-ray irradiation amount was 4.0 Hrad.
is the same as The results are shown in Table 1.

Comparative Examples 3~・ε3 Examples 1~4 and Comparative Examples 1~ except that T-rays are not irradiated
Compression set was measured for a test piece prepared in the same manner as in Example 2. The results are shown in Table 1.

Comparative Example 9 Diameter 29.0 mm manufactured using vulcanized butyl rubber whose composition was not shown in Table 2 and was manufactured under vulcanization conditions of 170° C. for 5 minutes.
The compression set of a cylindrical compression set test piece having a thickness of 12.7 mm was measured in the same manner as in Examples 1 to 4. The results are not shown in Table 2.

(Left below) -14= Machizuke blending ratio (middle/early part) Butyl rubber 80 [Dylembu 1] Pyrene terpolymer 20 Sulfur
0.9 inorganic filler
50 Sudearic acid 0.
! 5 Bent lead flower 3 Vulcanization accelerator 1 Extractable material Rubber composition prepared in Example 1 and Comparative Example 9 30q
300d! (extracted) in distilled water and autoclaved at 121°C for 20 minutes. Mancanic acid-16 (potassium-reducing substance, chloride, evaporation residue) and eluate tests were conducted in accordance with the Japanese Pharmacopoeia's "Test Method for Rubber Cells for Infusions" (Awadachi, Murasaki Tato absorption spectrum, curved button)7' The results are shown in Table 3.

Table 3 Example 1 Comparison ■dan Δl') HO, 280, 8: λ Ktln[), 13 SO originality 0.55
5.03 Substances △V (ml) Within 30 Within 30 Chloride (d) Below 1.1 Above 1.1 Evaporation residue (Illg) 0.1 0.
7UV absorption 0.153 (220nm) 1
．． 173 (230nm) spectrum 0.140
(24!+nm) 1.560 (3200m) Kanoyari (
pnn ) 0.005 or less 1.211
(9) Specific Effects of the Invention As mentioned above, the rubber molded product of the present invention is a molded product (62, It is characterized by improving the compression set by cross-linking the q.1 wire, so it is possible to improve the compression set by crosslinking the q.1 wire. The vulcanization process is a tribute to the vulcanization process, which solves problems such as elution of mulberry products such as il (agent), f room, etc., and provides sufficient <-r bullet 1 no. 1, low scum transmission P1 and 61, and small i-cho f
j-Excellent rubber moldings with shrinkage properties, such as containers for various containers, special T5 double-loaf bare-faced tubes, infusions) (T1, circulating fluids)■
It is suitably used as a stopper for medical equipment such as a medical device (and also for various other purposes such as connecting tubes to each other, as a bagging material, etc.). The molded product is made of elas 1 hemer compound (partially cross-linked butyl-F).
20 to 90% by weight of the polymer composition, and other components include uncured brominated butyl rubber or unvulcanized brominated butyl rubber or 0 to 70% of the polymer composition. %, or unvulcanized -f ethylene, or polyisobutylene, from 0 to 70% of the polymer composition, and further thermoplastic resins from 2 to 60% of the polymer composition.
If it contains, and when using the hexane-soluble part of cross-linked butyl rubber or partially cross-linked butyl rubber under 60% varnish, the radiation black color will be as early as 0. If it is between .1 and 5.0 Hrad, it will be better, and the above effect will be even more pronounced at 4T.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a vacuum blood collection tube using a rubber molded product according to the present invention as a stopper, and FIGS. DESCRIPTION OF SYMBOLS 1... Decompression blood collection tube, 2... Tubular part, 3... End [], 4... Stopper, b... Internal space.

Claims (8)

[Claims] (1) A rubber molded article, characterized in that the compression set is improved by crosslinking a molded article of an elastomer compound made of a polymer composition containing partially crosslinked butyl rubber by irradiating it with radiation. (2) The rubber molded article according to claim 1, wherein the partially crosslinked butyl rubber is contained in the elastomer compound in an amount of 20 to 90% by weight of the polymer composition. (3) Claim 2, wherein the elastomer compound contains unvulcanized chlorinated butyl rubber or unvulcanized brominated butyl rubber in an amount of 0 to 70% by weight of the polymer composition. The rubber molded product described in . (4) The elastomer compound contains unvulcanized butyl rubber or polyisobutylene in an amount of 0 to 70% by weight of the polymer composition. Rubber moldings. (5) The rubber molded product according to any one of claims 1 to 4, wherein the cyclohexane soluble portion of the partially crosslinked butyl rubber is 60% by weight or less of the partially crosslinked butyl rubber. (6) The rubber molded product according to any one of claims 1 to 5, which is crosslinked at a radiation dose of 0.1 to 5.0 Mrad. (7) The rubber molded article according to any one of claims 1 to 6, wherein the radiation irradiation is performed in air. (8) The rubber molded product according to any one of claims 1 to 7, wherein the molded product is a stopper for a closed container.