JP2784066B2 - Composition with excellent chlorofluorocarbon gas permeation resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a mechanical property suitable for a material of a flexible component such as a hose, a packing, an O-ring, a seal material used in a device for handling CFC gas. The present invention relates to a composition which is excellent and has excellent fluorocarbon gas permeation resistance.

(Prior Art) Conventionally, as a hose material used for transporting CFCs in a device for handling CFCs, for example, a car cooler,
Rubber hoses such as nitrile rubber, hydrin rubber and chloroprene rubber are used.

Until now, as a refrigerant gas for automotive coolers, Freon 12 containing fluorine atoms and chlorine atoms was used, replacing all hydrogen in hydrocarbons with halogens, but in recent years the ozone layer in the stratosphere has been destroyed, resulting in environmental abnormalities. Invite the freon 12
The use of Freon 22, Freon 134a or the like as a refrigerant in place of has been studied.

However, it has become clear that the conventionally used nitrile rubber, hydrin rubber, chloroprene rubber and the like have a large permeation amount of the refrigerant gas and pose a practical problem.

As a similar prior art, Japanese Patent Application Laid-Open No. 63-242539 proposes a method of using a chlorine-containing synthetic rubber having a crystalline region for a hose inner tube.In the technical content, the object of the present invention is to reduce the molecular weight. Freon 2 without chlorine in the molecule
2. The barrier effect is small for Freon 134a, etc., and it is not sufficient as a Freon resistant material.

(Problems to be Solved by the Invention) The object of the present invention is to provide a refrigerant that does not cause ozone layer depletion.
Freon 2 being considered for use in automotive coolers, etc.
2. It is an object of the present invention to provide a composition which is excellent in chlorofluorocarbon gas permeation resistance to fluorocarbon 134a and the like, and is also excellent in mechanical properties.

(Means and Actions for Solving the Problems) As a result of diligent studies conducted by the present inventors in order to improve the chlorofluorocarbon gas permeability, 2,3-dichloro-1,3-butadiene-based polymer was converted to chlorofluorocarbon 22 and chlorofluorocarbon. Low molecular weight like 134a,
In addition, they have found for the first time that they exhibit excellent CFC permeation resistance to CFCs containing no chlorine atom in the molecule.

2,3-dichloro-1,3-butadiene has a chlorine content of 57.8.
Despite the high weight percentage, the polymer obtained by polymerization has a double bond, so that the polymer becomes softer than expected and is suitable as a CFC-resistant material.

The 2,3-dichloro-1,3-butazineene-based polymer (abbreviated as DCBD-based polymer) has a small molecular weight as described above and exhibits a good barrier property to Freon gas containing no chlorine in the molecule. Has a high chlorine content in the DCBD-based polymer, which weakens the affinity for Freon gas, and furthermore, because chlorine is a steric hindrance, and because the DCBD-based polymer is a crystalline polymer, this has a combined barrier effect. It is considered to be effective.

However, the tear strength of the DCBD polymer is low among the mechanical strengths, and improvement in the use of the DCBD polymer is indispensable for use as a material for Freon gas resistance. As a result of repeated studies for improvement, a composition comprising 70 to 99% by weight of a DCBD-based polymer and 30 to 1% by weight of a chlorine-containing synthetic rubber shows excellent permeation resistance to the CFC gas and flexibility. The inventors have found that the present invention has excellent mechanical properties, and have completed the present invention.

 The present invention will be described in more detail below.

The DCBD polymer used in the present invention is 2,3-dichloro-
Includes 1,3-butadiene homopolymers and copolymers. Specific examples of monomers that can be used in obtaining the copolymer include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,
3-dimethylbutadiene, 2-chloro-1,3-butadiene, 1-chloro-1,3-butadiene, acrylic acid, methacrylic acid, acrylates, methacrylates, acrylonitrile, methacrylonitrile, and the like. It is not limited to. In the copolymer
Since the proportion of 2,3-dichloro-1,3-butadiene (abbreviated as DCBD monomer) affects the fluorocarbon gas permeability, the proportion of DCBD monomer in the copolymer is 70% by weight in order to achieve the object of the present invention. % Or more, more preferably 85% by weight or more.

The preferred molecular weight range of the DCBD-based polymer is 10,000 to 500,000 in weight average molecular weight. Weight average molecular weight 10,000
Since the mechanical strength of the obtained composition is relatively small when smaller, it is not preferable when a large mechanical strength is required for the molded member, and the workability of the obtained composition is poor when the weight average molecular weight is larger than 500,000. Is not preferred.
A more preferable range of the weight average molecular weight is 50,000 to 400,000.
It is.

The proportion of the DCBD-based polymer in the composition of the present invention is in the range of 70 to 99% by weight, more preferably in the range of 85 to 97% by weight. When the proportion of the DCBD-based polymer in the composition is less than 70% by weight, the chlorofluorocarbon gas permeability increases. On the other hand, when the content is more than 99% by weight, the tear strength is particularly low among the mechanical properties.

The chlorine-containing synthetic rubber used in the present invention is particularly preferably chloroprene rubber, chlorinated polyethylene rubber, chlorosulfonated polyethylene rubber, hydrin rubber, and halogenated butyl rubber, and the proportion in the composition is in the range of 30 to 1% by weight. A more preferred range is from 15 to 3% by weight. When the proportion of the chlorine-containing synthetic rubber in the composition is more than 30% by weight, the chlorofluorocarbon gas permeability increases. On the other hand, if it is less than 1% by weight, the effect of improving the tear strength among mechanical strengths is small.

There is no particular limitation on the chlorine-containing synthetic rubber, and the copolymer rubber and the chlorine content can be appropriately selected according to the purpose. Depending on the purpose, two or more rubbers can be used in combination. Among rubbers, chloroprene rubber is particularly preferable from the viewpoint of compatibility.

Examples of the polymerization method for obtaining the DCBD-based polymer used in the present invention include emulsion polymerization, solution polymerization, suspension polymerization, and bulk polymerization. Among them, the emulsion polymerization method is preferable.

For controlling the molecular weight of the DCBD polymer, a well-known regulator,
For example, n-dodecyl mercaptan, t-dodecyl mercaptan and the like can be used as desired.

As a method for obtaining the composition of the present invention, a DCBD polymer and a chlorine-containing synthetic rubber are mixed using a mixer generally used for kneading rubber, such as a roll, a Banbury mixer, a kneader, and an extruder. And a method in which a DCBD-based polymer latex and a chlorine-containing synthetic rubber latex are mixed in advance and then dried, and the like.

Further, in practical use, a vulcanizing agent can be added to the composition of the present invention, if desired, and used as a vulcanizing member. Examples of the vulcanizing agent used in obtaining the vulcanized member include sulfur and sulfur donors such as thiuram and thiazole, peroxides, polyamines, metal oxides, urethane vulcanizing agents, resin vulcanizing agents, sulfonating agents, and the like. Examples include a phenamide-based vulcanizing agent, a guanidine-based vulcanizing agent, a triazine-based vulcanizing agent, and an aldehyde-amine vulcanizing agent.

In addition, in obtaining a vulcanized member, various compounding agents generally compounded in rubber, for example, an antioxidant, a heat stabilizer,
Plasticizers, peptizers, dispersants, adhesives, extenders, coloring agents, reinforcing agents, lubricants, hydrogen chloride scavengers, and the like can be used as desired.

As described above, the composition of the present invention has excellent resistance to chlorofluorocarbon gas transmission, but can be combined with another rubber if desired to obtain a further excellent chlorofluorocarbon gas member. For example, a two-layer hose having the composition of the present invention in the inner layer and another vulcanized rubber layer in the outer layer, or the composition of the present invention in the middle layer and the other vulcanized rubber in the inner and outer layers A hose having a three-layer structure having a layer is exemplified.

(Examples) Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples unless it exceeds the gist of the present invention.

 The DCBD polymer was produced by the following method.

Using a 10 stainless steel polymerization vessel equipped with a stirrer, a mixed catalyst of potassium persulfate / anthraquinone sulfonated sodium salt was sequentially added under a nitrogen atmosphere according to the following polymerization recipe using a total of 3.0 kg of the monomer (described in Table 1). While 40
Polymerization was carried out at ° C. When the conversion reached 80% or more, thiodiphenylamine and tert-butylcatechol were added to terminate the polymerization. After removing unreacted monomers under reduced pressure, a polymer was obtained by freeze-drying.

The composition of the obtained polymer was analyzed by chlorine analysis, and the weight average molecular weight was analyzed by high temperature GPC.

Polymerization recipe Monomer 100 parts by weight Pure water 150 Disproportionated rosin acid 5 Potassium persulfate 0.002 Sodium salt of a condensate of naphthalenesulfonic acid and formaldehyde 0.8 Sodium hydroxide 0.8 Sodium acid sulfite 0.3 n-Dodecyl mercaptan Obtained as shown in Table 1 The results of the obtained DCBD-based polymer are summarized in Table 1.

Example 1 90 parts by weight of a 2,3-dichloro-1,3-butadiene homopolymer (Polymer A) shown in Table 1 was charged into a Brabender plastograph (manufactured by Brabender) set at 180 ° C. and 50 rpm. After melting for 3 minutes, 10 parts by weight of chloroprene rubber (Denka chloroprene M-40: manufactured by Denki Kagaku Kogyo KK) was added and kneaded for 5 minutes. The kneaded material is heated at a temperature of 200 ° C and a pressure of 100
Press with a kg / cm ² electrothermal press for 5 minutes, thickness 2mm, length 20c
m, a sheet 20 cm wide was formed. Each physical property was measured by the following method using this molded sheet.

The tensile test and the tear test were measured according to JIS K6301.

As shown in FIG. 1, the fluorocarbon gas permeability is as follows. A fluorocarbon gas 2 is placed in a stainless steel cup 1 and a circularly cut measurement sample 3 is placed on the stainless steel cup 1, and then a punching metal 4 and a holding ring 5 are placed on the lid. The stainless steel cup 1 is put in a constant temperature bath at 80 ° C., and the change over time in the weight loss is tracked to obtain the unit thickness, the unit area, and the amount of CFC permeated per unit time. Was evaluated.

 The measurement results are summarized in Table 2.

Examples 2 to 8 According to the same method as in Example 1, the DCBD-based polymer and chloroprene rubber (Denkachloroprene M-4) shown in Table 1 were used.
0), chlorinated polyethylene rubber (Eraslen 401A: manufactured by Showa Denko KK), chlorosulfonated polyethylene rubber (DENKA
CSM430: manufactured by Denki Kagaku Kogyo Co., Ltd., hydrin rubber (Epichromer H, manufactured by Osaka Soda Co., Ltd.) or halogenated butyl rubber (chlorobutyl 1066: manufactured by Exxon Co., Ltd.) in accordance with the mixing ratio shown in Table 2. PA
(Phenyl-1-naphthylamine); Ouchi Shinko Chemical Co., Ltd. was used in combination. After preparing the sample, the physical properties were measured. Table 2 shows the measurement results.

Comparative Examples 1 to 5 In accordance with the same method as in Example 1, physical properties were measured based on the formulations shown in Table 2. The results are summarized in Table 2.

Example 9 80 parts by weight of the DCBD polymer / polymer A shown in Table 1
20 parts by weight of chloroprene rubber (M-40), stearic acid 0.1 part
5 parts by weight, 4 parts by weight of magnesia, 1 part by weight of Nocrack PA
The mixture was kneaded with a hot roll at 100 ° C. for 15 minutes. After cooling, 4 parts by weight of dicumyl peroxide and 1 part by weight of triallyl isocyanurate were further added and kneaded with a low-temperature roll at 40 ° C. for 10 minutes to prepare an uncured sulfuric acid compound. A sample was prepared in the same manner as in Example 1 and the physical properties were measured.
Table 3 shows the measurement results.

Example 10 The same various additives as in Example 9 were added to 90 parts by weight of the DCBD polymer / polymer C and 10 parts by weight of chlorinated polyethylene rubber (Eraslen 401A) shown in Table 1 to obtain Example 9.
A sample was prepared by the same method as in Example 1, and the physical properties were measured. Table 3 shows the measurement results.

Comparative Example 6 Chloroprene rubber (Denka chloroprene M-40) 100
Parts by weight, 0.5 parts by weight of stearic acid, 4 parts by weight of magnesia, 50 parts by weight of carbon black, 2 parts by weight of Nocrack PA, and 10 parts by weight of dioctyl phthalate (DOP) are kneaded with a low-temperature roll at 40 ° C. for 20 minutes, and then dicumyl peroxide 4 Parts by weight, 1 part by weight of triallyl isocyanurate,
An unvulcanized compound was prepared by kneading for 10 minutes. The unvulcanized compound was press-vulcanized for 30 minutes using an electrothermal press at a temperature of 160 ° C. and a pressure of 100 kg / cm ² , and the physical properties were measured as in Example 1. Table 3 shows the measurement results.

Comparative Example 7 100 parts by weight of nitrile rubber (Nipol 1042; manufactured by Zeon Corporation), 1 part by weight of stearic acid, 5 parts by weight of zinc white, and 60 parts by weight of carbon black were kneaded with a low-temperature roll at 40 ° C. for 20 minutes, and then benzothiazyl was added. 1.5 parts by weight of sulfide, 0.5 parts by weight of tetramethylthiuram disulfide, 1.5 parts by weight of sulfur,
2 parts by weight of Nocrack PA was added and kneaded for 10 minutes to prepare an unvulcanized compound. Vulcanization was performed in the same manner as in Comparative Example 4, and the physical properties were measured. Table 3 shows the measurement results.

Comparative Example 8 100 parts by weight of a chlorinated polyethylene (Eraslen 404B; manufactured by Showa Denko KK) having a chlorine content of 40% by weight and a crystallinity of 15 cal / g,
10 parts by weight of magnesia, 60 parts by weight of carbon black, DOP1
After 0 parts by weight and 5 parts by weight of talc were kneaded with a roll at 50 ° C. for 20 minutes, the mixture was cooled to 40 ° C., 5 parts by weight of dicumyl peroxide was added, and kneaded for 10 minutes to prepare an unvulcanized compound. Vulcanization was performed in the same manner as in Comparative Example 4, and the physical properties were measured.
Table 3 shows the measurement results.

(Effects of the Invention) As is clear from Tables 2 and 3, the composition of the present invention has a small molecular weight such as Freon 22 and Freon 134a, and has a low permeation amount of Freon gas having no chlorine atom in the molecule. It was confirmed that it was also excellent in mechanical strength.

As described above, the composition according to the present invention is a composition that is extremely useful for hoses, packings, O-rings, sealing materials, and the like, which are required to be in contact with the above-mentioned refrigerants such as automotive coolers and air conditioners and have flexibility. is there.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for measuring CFC gas permeability. 1 Stainless steel cup 2 Freon gas 3 Circular measurement sample 4 Punched metal 5 Pressing ring 6 Bolt 7 Nut

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ identification code FI (C08L 15/02 23:34) (C08L 15/02 71:00) (58) Investigated field (Int.Cl. ⁶ , DB Name) C08L 9/00-21/02 C08L 23 / 28,23 / 34 C08L 71/00-71/03 CA

Claims (2)

(57) [Claims] 1. A 2,3-dichloro-1,3-butadiene polymer
A composition having excellent fluorocarbon gas permeability, comprising 70 to 99% by weight and 30 to 1% by weight of a chlorine-containing synthetic rubber. 2. A molded member having excellent chlorofluorocarbon gas permeability, obtained by molding the composition according to claim 1.