JP3438566B2 - Molding materials used for applications that come into contact with carbon dioxide - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to contact with carbon dioxide gas .
The present invention relates to a molding material used for various purposes . For more details,
The present invention relates to a molding material used for molding a sealing material having excellent carbon dioxide gas resistance.

[0002]

2. Description of the Related Art Almost all refrigerants used in car air conditioners, refrigerators, etc. are CFCs, but they cause environmental damage.
Due to problems such as ozone layer depletion and global warming, the next-generation refrigerant is being investigated, and one of the leading candidates is carbon dioxide. In the case of the conventional CFC gas refrigerant, sealing materials such as hydrogenated NBR and EPDM (ethylene / propylene / diene copolymer rubber) are used, but these rubber materials swell greatly when contacted with carbon dioxide gas, It also has the drawback of causing foaming. In particular, when a non-reinforcing filler having a large particle size, such as mica or graphite, is added for the purpose of reducing the gas permeability of these rubber materials, foaming is more likely to occur, and for contact with carbon dioxide gas .
It cannot be used as a molding material used in the process.

In the case of hydrogenated NBR, in order to enhance its sealing ability against carbon dioxide gas, studies have been made on laminating or blending a material having low carbon dioxide gas permeability thereto. However, the technique of laminating and blending such materials has a drawback in terms of adhesion and workability with hydrogenated NBR materials.

On the other hand, there is a material having low carbon dioxide gas permeability such as vinylidene fluoride resin, but this material is greatly different from the rubber material in terms of workability and flexibility, and when it is used as a sealing material, When the shaft is eccentric, the followability with respect to the shaft is inferior, and a decrease in the followability causes a minute gap between the seal material and the shaft, which inevitably leads to leakage of the sealing medium, which inevitably results in a decrease in sealing performance.

Further, the vinylidene fluoride resin sealing material is easily scratched by splines when it is incorporated into a shaft that has been splined (a groove is formed in the axial direction). Therefore, the sealing performance may not be maintained.

Further, it is known that the fluororubber thermoplastic elastomer can be used as a molding material such as a lubricating oil-resistant seal material, as disclosed in JP-A-59-40066, JP-A-6-25500 and JP-B-3. -2197 publication, 3-59937 publication, 7-68430
However, in these descriptions, M, which is generally used as a reinforcing filler in fluororubber, is disclosed.
T carbon black (particle size 201 to 500 nm) is used as it is.

However, the sealing material formed from the fluorocarbon rubber-based thermoplastic elastomer composition containing such MT carbon black is not only low in carbon dioxide gas permeation resistance and swelling resistance but also in contact with carbon dioxide gas. It has the drawback that foaming (blister) caused by
The molding material that has been found to not be used safely.

[0008]

An object of the present invention is to solve the above-Bro
Is a molding material made by adding a reinforcing filler to a thermoplastic fluoroelastomer elastomer, and has excellent gas permeation resistance and swelling resistance, especially when used for contact with carbon dioxide gas. It is to provide a product excellent in foamability.

[0009]

The object of the present invention is as follows.
This is achieved by using a reinforcing filler having a particle size of 100 nm or less, and preferably such reinforcing filler and non-reinforcing filler are used in combination.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION There are two types of fluororubber thermoplastic elastomers, a block type and a graft type. In the present invention, these two types of inner block type are used.

The block type fluororubber thermoplastic elastomer is a fluororubber (soft segment) that utilizes the unique chain transfer reaction behavior (telomerization) of iodine compounds in radical polymerization of fluoromonomers.
It is an ABA type thermoplastic elastomer in which a fluororesin (hard segment) is triblock-bonded. These soft segment chains and hard segment chains are firmly bonded in one molecule, and have a structure in which the soft segments are reinforced by chemical bonds. Further, since it has the characteristics of both rubber and resin and has thermoplasticity, it can be molded without undergoing crosslinking, and the molded body has rubber elasticity.

Examples of the monomer constituting the soft segment include vinylidene fluoride, tetrafluoroethylene, hexafluoropropene and the like. For example, vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer segment and the like are formed. . Further, examples of the monomer constituting the hard segment include vinylidene fluoride, ethylene, tetrafluoroethylene and the like, and for example, a polyvinylidene fluoride segment, a tetrafluoroethylene-ethylene copolymer segment and the like are formed.

For these block type fluororubber thermoplastic elastomers, a reinforcing filler having a particle diameter of 100 nm or less, generally carbon black or silica, is used, and preferably carbon black is used. As carbon black having a particle size of 100 nm or less, SAF (particle size 11 to 19 nm),
ISAF (particle size 20-25nm), HAF (particle size 26-30nm), XC
F (particle size 31 to 39 nm), FEF (particle size 40 to 48 nm), GPF (particle size 49 to 60 nm), SRF (particle size 61 to 100 nm) and the like are used. If a reinforcing filler having a particle size larger than this is used, the reinforcing property is low, and satisfactory foaming resistance cannot be obtained. These reinforcing fillers are thermoplastic elastomers.
It is used in a ratio of about 5 to 100 parts by weight, preferably about 10 to 70 parts by weight, per 100 parts by weight. When used in a ratio higher than this, it is difficult to mix with the thermoplastic elastomer,
On the other hand, if the ratio is less than this, the foaming resistance effect cannot be obtained.

As non-reinforcing fillers used in combination with these reinforcing fillers, calcium metasilicate, diatomaceous earth, graphite, mica, calcium carbonate, zinc oxide, etc. are used in an amount of about 100 parts by weight of the thermoplastic elastomer. 5 to 100 parts by weight, preferably about 5 to 60 parts by weight, and about 10 to 200 parts by weight, preferably about 1 as a total amount with the reinforcing filler.
It is used in a proportion of 0 to 100 parts by weight. These non-reinforcing fillers are preferably used after being surface-treated with a silane coupling agent or the like in consideration of wettability at the interface with the thermoplastic elastomer. The particle size is not particularly limited, and powdery ones are generally used.

An organic peroxide is further blended as a cross-linking agent in the molding material comprising the above components. Examples of the organic peroxide include 1,1-bis (tertiary butylperoxy) -3,
5,5-trimethylcyclohexane, 2,5-dimethylhexane
-2,5-dihydroxy peroxide, di-tert-butyl peroxide, tert-butyl cumyl peroxide, di-cumyl peroxide, α, α-bis (tertiary butyl peroxy) -p-
Diisopropylbenzene, 2,5-dimethyl-2,5-di (tertiary butylperoxy) hexane, 2,5-dimethyl-2,5-di (tertiary butylperoxy) hexyne-3, benzoyl peroxide, 3-Butylperoxybenzene, 2,5-dimethyl-2,5-
Di (benzoylperoxy) hexane or the like is about 0.1 to 20 parts by weight, preferably about 100 parts by weight, per 100 parts by weight of the thermoplastic elastomer.
It is used in a proportion of 0.5 to 10 parts by weight.

Various additives including a polyfunctional unsaturated compound crosslinking aid typified by triallyl isocyanurate and the like are blended and used in the molding material containing the above-mentioned respective components as essential components.

Further, in order to reduce the viscosity of the molding material, about 5 to 60 parts by weight, preferably about 5 to 40 parts by weight of an organic solvent such as toluene, xylene, n-hexane, etc., per 100 parts by weight of the thermoplastic elastomer are used. Aromatic or aliphatic hydrocarbons, carboxylic acid esters such as ethyl acetate, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, alcohols such as methanol and ethanol, ethers such as tetrahydrofuran, dimethylacetamide,
It is also effective to add at least one organic solvent such as an aprotic polar solvent such as dimethylformamide or N-methylpyrrolidone, or a mixture of these with water.

The molding material is prepared by kneading each compounding component excluding the cross-linking agent with a kneader, kneading the mixture with a heating roll, and then adding the cross-linking agent. Method of adding and mixing each filler by the method of introducing each compounding component excluding the cross-linking agent from the twin-screw extruder to the single-screw extruder, and then adding the cross-linking agent and processing into a sheet shape by a T-die or the like Etc. Furthermore, it is preferable from the viewpoint of foaming resistance to remove air bubbles and volatile components in the molding material with a vent type extruder.

The prepared molding material is molded by using a compression molding machine, an injection molding machine or the like at about 150 to 220 ° C. and about 100 to 1
500 Kgf / cm ² , press vulcanization for about 1-20 minutes and about 180-23
It is carried out by oven vulcanization (secondary vulcanization) at 0 ° C. for about 1 to 24 hours.

[0020]

EFFECTS OF THE INVENTION The molding material according to the present invention, which contains a rubber material as a main component, exhibits excellent gas permeation resistance to carbon dioxide gas, swelling resistance and foaming resistance. Therefore, this molding material can be effectively used for molding sealing materials (lip seals, packings, gaskets, O-rings, etc.) that come into contact with carbon dioxide, hoses or tubes, diaphragms and the like.

[0021]

EXAMPLES The present invention will now be described with reference to examples.

Example 1 Block type fluororubber thermoplastic elastomer (Daikin product Daier Thermo T630) 100 parts by weight FEF carbon black 35 〃 magnesium oxide 5 〃 organic peroxide (Nippon Oil & Fat Products Perkmill D) 1.5 〃 triallyl isocyanurate ( Nippon Kasei Product Tyke M60, 60%) 3〃 Mix each compounding component except organic peroxide with 3L kneader,
Next, after kneading with a roll (80 ° C.), an organic peroxide was blended. This compound was subjected to press vulcanization at 195 ° C. for 8 minutes and oven vulcanization (secondary vulcanization) at 200 ° C. for 15 hours to vulcanize and form two circular sheets having a diameter of 90 mm and a thickness of 0.5 mm. . One of them was used as a circular sample having a diameter of 50 mm, and the other was cut into a square sample of 30 × 30 mm.

With respect to the circular sample, using a gas palm 100 type gas permeability measuring device (manufactured by JASCO Corporation), under the condition of 5 Kgf / cm ² , carbon dioxide gas permeability (unit: cm ³ · mm / m ² · at
m · 24 hr) was measured. For square samples, the internal volume is 50 m
After putting in the pressure resistant container of l, carbon dioxide gas was injected into the pressure resistant container, left at 100 ° C., 80 Kgf / cm ² , for 2 hours, then returned to normal temperature and pressure, and the weight change of the sample ( The weight swelling ratio (unit: weight%) was measured, and the number of blister occurrences (unit: unit / cm ² ) on the sample surface was counted.

Example 2 In Example 1, the amount of FEF carbon black was changed to 10 parts by weight, and 30 parts by weight of acetone and 10 parts by weight of methanol were further added and used.

Example 3 In Example 2, instead of FEF carbon black,
The same amount of silica (A200, manufactured by Aerosil) was used.

Comparative Example 1 In Example 1, no FEF carbon black was used.

Comparative Example 2 In Example 1, instead of FEF carbon black,
The same amount of MT carbon black was used.

Comparative Example 3 100 parts by weight of hydrogenated NBR (Zeon Pole 2010 manufactured by Nippon Zeon Co., Ltd. ) FEF carbon black 35 〃 zinc oxide 5 〃 organic peroxide (peroximon F40 manufactured by Nippon Oil and Fats Co., Ltd. ) 8 〃 stearic acid 0.5 〃 or more Kneading and vulcanization in the same manner as in Example 1 using components (however, press vulcanization at 180 ° C. for 4 minutes, secondary vulcanization at 165
(° C, 30 minutes) and measurements were taken.

Comparative Example 4 100 parts by weight of fluororubber (Viton B manufactured by DuPont) FEF carbon black 35 〃 magnesium oxide 5 〃 N, N′-dicinnamylidene-1,6-hexanediamine 3 〃 Kneading and vulcanization similar to Example 1 (however, press vulcanization at 205 ° C. for 4 minutes, secondary vulcanization at 215
C., 22 hours) and measurements were taken.

Example 4 In Example 1, instead of 35 parts by weight of FEF carbon black, 15 parts by weight of SRF carbon black and silica were used.
20 parts by weight of (Aerosil A200) were used.

Example 5 In Example 1, instead of 35 parts by weight of FEF carbon black, 10 parts by weight of HAF carbon black and 20 parts by weight of calcium metasilicate (NYAD1250 manufactured by Tomoe Kogyo Co., Ltd.) were used.

Example 6 In Example 1, instead of 35 parts by weight of FEF carbon black, 7 parts by weight of ISAF carbon black and 25 parts by weight of graphite (graphite AO manufactured by Nichiden Carbon Products) were used, and the amount of organic peroxide was 1 part. The amount of triallyl isocyanurate was changed to 3.5 parts by weight.

Example 7 In Example 1, instead of 35 parts by weight of FEF carbon black, 10 parts by weight of ISAF carbon black and mica were used.
35 parts by weight of mica powder A21A (Yamaguchi Mica Industrial Co., Ltd.) was used, the amount of organic peroxide was changed to 1 part by weight, and the amount of triallyl isocyanurate was changed to 3.5 parts by weight.

Example 8 In Example 7, the same amount of silica (Aerosil A200) was used instead of 10 parts by weight of ISAF carbon black.

Comparative Example 5 In Example 7, the same amount of MT carbon black was used instead of 10 parts by weight of ISAF carbon black.

Example 9 In Example 7, instead of 35 parts by weight of mica, surface-treated calcium metasilicate (Walrus coat manufactured by Tomoe Kogyo Co., Ltd.)
20 parts by weight were used.

[0037]   Comparative Example 6   Hydrogenated NBR (Zeon Paul Z1010 manufactured by Zeon Corporation) 100 parts by weight   FEF carbon black 10〃   Magnesium oxide 5〃   Acetone 30〃   Methanol 10〃   Organic peroxide (Park Mill D) 1.5〃   Triallyl isocyanurate (Tyke M60) 3 〃

Kneading, vulcanization and measurement were carried out in the same manner as in Comparative Example 3 using each of the above components.

The measurement results in each of the above Examples and Comparative Examples are shown in Table 1 below. Table 1 Example CO ₂ permeability Weight swelling rate Blister occurrence Example 1 380 0.25 0 〃 2 400-0 〃 3 420-0 Comparative example 1 970 0.60 8 〃 2 410 0.30 6 〃 3 1750 0.29 10 〃 4 570 2.50 13 Example 4 379 0.24 0 〃 5 375 0.25 0 〃 6 379 0.26 0 〃 7 370 0.25 0 〃 8 382 0.23 0 Comparative Example 5 405 0.31 9 Example 9 379 0.26 0 Comparative Example 6 1350-10

Reference Example 1 (Example 10) Block type fluororubber thermoplastic elastomer (Dyer Thermo T630) 100 parts by weight FEF carbon black 10 〃 graphite 5 〃 calcium metasilicate 20 〃 stearic acid 1 〃 magnesium oxide 6 〃 organic peroxide Oxide (Park Mill D) 1.4〃 Triallyl isocyanurate 1〃

Each compounding component except the organic peroxide was kneaded with a 3 L kneader (60 ° C.) and then kneaded with a roll (80 ° C.), and then the organic peroxide was compounded. This compound was press vulcanized at 195 ° C., 100 Kgf / cm ² , 4 minutes and 200
Oven vulcanization was performed at 6 ° C for 6 hours to obtain a vulcanized sheet having a thickness of 2 mm.

About the obtained vulcanized sheet, room temperature, 5 Kg
f / cm ² , 60 minutes (N ₂ , O ₂ ) or 30 minutes (CO ₂ )
A gas permeability test was carried out by a method using Gas Palm 100 manufactured by JASCO Corporation.

Reference Example 2 (Example 11) In Reference Example 1, instead of FEF carbon black,
The same amount of silica (Aloedir product A200) was used.

Reference Example 3 (Example 12) In Reference Example 1, graphite and calcium metasilicate which are non-reinforcing fillers were not used, and the amount of FEF carbon black was changed to 55 parts by weight.

Reference Example 4 In Reference Example 1, the same amount of hydrogenated NBR (Zetpol 1010) was used in place of the block type fluororubber thermoplastic elastomer, and the vulcanization conditions were 180 ° C. and 100 Kgf / c.
It was changed to m ² for 8 minutes press vulcanization and 150 ° C. for 1 hour oven vulcanization.

The permeation amounts of various gases (unit: cm ³ · mm / m ² · atm, 24 hr) measured in each of the above reference examples are shown in Table 2 below. Table 2 Measurement gas Reference example 1 Reference example 2 Reference example 3 Reference example 4 Nitrogen gas 20 5 25 20 Oxygen gas 60 55 115 70 Carbon dioxide gas 381 390 423 1320

From these results, when hydrogenated NBR was used, it showed an excellent gas barrier property against nitrogen gas and oxygen gas, but did not have a gas barrier property against carbon dioxide gas. It is noted that the present invention is remarkably excellent in gas barrier property against carbon dioxide gas.

Front page continuation (72) Inventor Hironori Minagawa, 25, Wadai, Tsukuba, Ibaraki Prefecture, NOK Co., Ltd. (72) Inventor, Osamu Kobayashi, 25, Wadai, Tsukuba, Ibaraki, NOK Co., Ltd. (56) References Special Kaihei 4-209643 (JP, A) JP 7-11087 (JP, A) JP 8-151450 (JP, A) JP 61-138663 (JP, A) JP 6-41378 ( JP, A) JP-A-2-261850 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08J 3/00-3/28 C08L 1/00-101/16

Claims (7)

(57) [Claims] 1. A molding material for use in contacting with carbon dioxide gas , which is obtained by adding a reinforcing filler having a particle size of 100 nm or less to a block type fluororubber thermoplastic elastomer. 2. The molding material according to claim 1, further comprising a non-reinforcing filler . 3. The molding material according to claim 1, wherein an organic peroxide crosslinking agent is added . 4. The molding material according to claim 1, 2 or 3 to which an organic solvent is added . 5. A sealing material used for contacting with carbon dioxide gas molded from the molding material according to claim 1, 2, 3 or 4. 6. A hose or tube for use in contact with carbon dioxide gas , which is molded from the molding material according to claim 1, 2, 3 or 4. 7. A diaphragm for use in contact with carbon dioxide gas molded from the molding material according to claim 1, 2, 3 or 4.