JPH0784556B2 - Elastomer-like composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to an elastomeric composition having excellent processability and fluorinated organic compound gas permeability, and more specifically, an apparatus for handling a fluorinated organic solvent and the like. In particular, it relates to an elastomeric composition suitable for producing flexible parts and the like.

(Prior Art) In recent years, the fluorine-based refrigerant R-12, which has been widely used as a refrigerant for refrigerators such as automobile coolers, has come to be feared as one of the depleting factors of the atmospheric stratospheric ozone layer, and as an alternative refrigerant. The use of R-22, R-134, etc. has begun to be studied worldwide.

In the conventional refrigeration system using R-12 as a refrigerant,
Oil-resistant rubber such as nitrile rubber (NBR) has generally been used in the parts of the hose for pipes and the seals that come into contact with the refrigerant gas. However, R-22 and R-134
In a new refrigerator system that uses such as a refrigerant,
Conventionally used oil-resistant rubber such as NBR has a large amount of refrigerant gas permeation and cannot withstand use, so the development of new rubber materials has been awaited.

On the other hand, an elastomeric plastic composition comprising a polyamide resin and epichlorohydrin rubber is known (Japanese Patent Laid-Open No. Sho 61-242).
57-5753). The composition comprises a polyamide resin in an amount sufficient to impart thermoplasticity to the composition and epichlorohydrin rubber dispersed in the resin matrix in a sufficiently small particle size, the rubber particles being the composition. Although it has been dynamically vulcanized to a degree sufficient to impart rubber-like elasticity, it has the drawback that it has poor flow characteristics and is difficult to process and mold. For example, injection molding products are prone to flow marks, and it is necessary to design a special mold to minimize the generation of flow marks. Further, there is a method of adding a plasticizer in order to improve the flow characteristics of such a composition, but the addition of the plasticizer generally has a drawback of increasing gas permeation. Furthermore, in order to achieve both good flow characteristics and gas permeation resistance, a method of increasing the fraction of the polyamide resin in the composition is conceivable, but in this case, the elastomeric characteristics are impaired, so that a hose or the like It is difficult to use for applications requiring flexible properties.

(Problems to be Solved by the Invention) As a result of intensive research to solve the above-mentioned drawbacks, the present inventor has found that liquid epichlorohydrin polymer is dispersed in a composition in which crosslinked epichlorohydrin rubber particles are dispersed in a polyamide resin. By dispersing the coalescence, it was found that it is possible to obtain an elastomeric composition having excellent process flow characteristics without reducing the fluorine-based refrigerant gas permeability and mechanical properties,
The present invention has been completed.

(Means for Solving Problems) Thus, according to the present invention, (A) polyamide resin 30 to 70
% By weight, 70 to 30% by weight of (B) epichlorohydrin rubber and 3 to 30% by weight based on the sum of (C) (A) + (B)
Of the liquid epichlorohydrin polymer having a number average molecular weight of 5,000 or less, an elastomeric composition in which epichlorohydrin rubber is dispersed as crosslinked rubber particles in a polyamide resin.

The polyamide resin used in the present invention includes a homopolymer resin having a repeating amide bond unit in the polymer chain, a copolymer resin, a multicomponent copolymer resin, and a high molecular weight crystalline or glassy polymer resin. Is. Examples of polyamide resins include polycaprolactam (nylon-6), polylauryllactam (nylon-12), polyhexamethylene adipic amide (nylon 6,6), polyhexamethylene azelaic amide (nylon-6,9). , Polyhexamethylene sebacic acid amide (nylon-6,10), polyhexamethyleneisophthalamide (nylon-6, IP), polyaminoundecanoic acid (nylon-11) and polymers of caprolactam, hexamethylenediamine, adipic acid (nylon) -6, 66) and the like. Preferably a crystalline polyamide resin, the higher the crystallinity, the oil resistance,
Excellent resistance to freon gas permeation. Although the softening point and melting point of the polyamide resin are not limited, those having a temperature of 160 to 220 ° C. are preferable in view of the thermal stability of the epichlorohydrin rubber.

Epichlorohydrin rubber used in the present invention, epichlorohydrin homopolymer rubber (CO), epichlorohydrin-ethylene oxide copolymer rubber (ECO), epichlorohydrin-allyl glycidyl ether copolymer rubber,
Homopolymers and epichlorohydrin of epichlorohydrin such as epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer rubber (ETCO) and epichlorohydrin-propylene oxide-allyl glycidyl ether terpolymer rubber It is a binary or multi-component copolymer rubber with another monomer copolymerizable with hydrin. The molecular weight of the epichlorohydrin rubber is not particularly limited, but a polymer rubber having a number average molecular weight of 20,000 or more, which is usually used as a solid rubber by vulcanization, is preferable. With regard to resistance to permeation to R-22 and the like, it is preferable that the content of the epichlorohydrin monomer is high, and especially the content of the epichlorohydrin monomer is
80% or more is desirable.

The liquid epichlorohydrin polymers used in the present invention are epichlorohydrin homopolymers having a number average molecular weight of 5,000 or less and epichlorohydrin-ethylene oxide copolymers. Liquid epichlorohydrin homopolymer is preferable for improving gas permeation resistance to R-22 and the like.
In the present invention, when the number average molecular weight of the liquid epichlorohydrin polymer exceeds 5,000, the plasticity of the epichlorohydrin rubber is poor, and the effect of improving the flow characteristics of the composition is small, which is not preferable. It is preferably in the range of 1,000 to 4,500.

The composition of the present invention is blended with 30 to 70% by weight of polyamide resin, 70 to 30% by weight of crosslinked epichlorohydrin rubber, and 3 to 30% by weight based on the total amount of liquid epichlorohydrin polymer. The composition is If the proportion of polyamide resin is less than 30% by weight or the proportion of epichlorohydrin rubber exceeds 70% by weight, oil resistance and fluorine-based refrigerant gas permeability are poor and thermoplasticity is reduced, making molding difficult, and elastomer The loss of sexual character departs from the object of the present invention. Further, if the proportion of the liquid epichlorohydrin polymer is less than 3% by weight, the plasticizing effect does not appear and the flow characteristics are not improved. On the other hand, if it exceeds 30% by weight, the tensile strength of the composition is lowered, the permanent elongation is large, the elastomeric property is lost, and the fluorine-based refrigerant gas permeability is deteriorated. The preferred composition ratio of the composition of the present invention is 40 to 60% by weight of polyamide resin, 60 to 40% by weight of epichlorohydrin rubber, and 5 to 20% by weight of liquid epichlorohydrin polymer based on the total amount thereof.

In the present invention, it is necessary that the epichlorohydrin rubber is dispersed as crosslinked rubber particles in the polyamide resin and the liquid epichlorohydrin polymer is added. The liquid epichlorohydrin polymer may have a structure dissolved in the crosslinked epichlorohydrin rubber particles and / or a structure dispersed in the polyamide resin. There are no particular restrictions on the dispersed particle size, particle shape, dispersion form and degree of vulcanization of the crosslinked rubber particles, but in order to achieve the object of the present invention, the dispersed particle size is preferably 5 microns ( μm) or less, and the degree of crosslinking of the dispersed particles is 95% or more in terms of gel content. Here, the gel content of the rubber means the weight% of the insoluble matter that does not dissolve in benzene with respect to the rubber.

The composition of the present invention comprises a method of blending a crosslinked rubber powder of a polyamide resin and epichlorohydrin rubber and a liquid epichlorohydrin polymer, or a method of dynamically vulcanizing epichlorohydrin rubber while the polyamide resin is melted and liquid epichlorohydrin rubber. It can be produced by a method of blending a chlorohydrin polymer. A preferred manufacturing method is a dynamic vulcanization method. The method of blending the crosslinked rubber powder of epichlorohydrin rubber and the liquid epichlorohydrin polymer is a crosslinked rubber powder obtained by performing a crosslinking reaction in a rubber particle dispersion liquid such as an emulsion or suspension, or by kneading the rubber. Is a method of blending a crosslinked rubber powder obtained by vulcanization with a liquid polymer, or a method in which a rubber mixed with a liquid polymer in advance is similarly made into a crosslinked rubber powder and blended. The dynamic vulcanization method is a method in which rubber or a rubber and a liquid polymer are added while the polyamide resin is melted, and the rubber is vulcanized by a vulcanizing agent of the rubber while kneading. The liquid polymer can also be added after the completion of dynamic vulcanization. For dynamic vulcanization, an apparatus usually used for kneading rubber or resin, for example, a closed kneader such as a Brabender mixer, a Banbury mixer, a kneader, or a kneading extruder can be used. Above all, it is preferable to use a kneader having a high shearing force to reduce the dispersed particle size of the dynamic vulcanizate in order to provide excellent physical properties.

The vulcanizing agent used for the dynamic vulcanization is not particularly limited, and a vulcanizing agent used for vulcanizing an ordinary epichlorohydrin rubber can be used. The same applies to the amount used. For example, vulcanizing agents for metal oxides such as magnesium oxide and lead oxide, thioureas such as ethylene thiourea, monomethyl thiourea and trimethyl thiourea, and vulcanizing agents in combination with metal oxides, trithiocyanuric acid, 2-dimethylamino −4,6−
Combination use of triazine thiol derivative such as mercapto-s-triazine and metal oxide Vulcanizing agent system, thiuram such as tetramethylthiuram disulfide, hexamethylenediamine carbamate, N, N'-dicinnamylidene-1,6
-A combination of amines such as hexanediamine, thioureas, triazine thiols, thiurams or amines with sulfur or a sulfur compound in combination with a vulcanizing agent system. The dynamic vulcanizing agent may be premixed with epichlorohydrin rubber to form a masterbatch and added to the molten polyamide resin, or may be added after mixing the molten polyamide resin and epichlorohydrin rubber.

The elastomeric compositions of the present invention can be modified in properties by the addition of additives commonly used in the polyamide resin and rubber industries. Examples of such additives include fillers / reinforcing agents such as carbon black, silica, clay, titanium dioxide, calcium carbonate and other pigments, zinc oxide, stearic acid, vulcanizing agents, vulcanization accelerators, anti-aging agents. Examples include agents, stabilizers, lubricants, foaming agents, pressure-sensitive adhesives, adhesives, plasticizers, extending oils, coupling agents, and short glass fibers, short cellulose fibers, discontinuous fibers such as aramid pulp, and the like. A preferred addition method is a method of adding these additives to a polyamide resin or rubber before dynamic vulcanization to obtain a masterbatch.

As used in the present invention, "elastomer-like" means that it is stretched to 150% (1.5 times) of its original length at room temperature, released for 10 minutes and then released to reach 130% of its original length within 30 minutes. It means the property of returning to% (1.3 times).

(Effect of the Invention) Thus, according to the present invention, there is provided an elastomeric composition having improved thermoplastic moldability, mechanical properties, and gas permeation resistance to fluorinated organic compounds, as compared with the prior art.

The elastomeric composition of the present invention includes tires that require oil resistance, hoses, seals and gaskets, belts, boots, rolls, and particularly the above-mentioned other substances that require fluorinated organic compound gas permeability. Suitable for various parts and applications. Another use of the compositions of the present invention is in blending with polyamide and polyester resins. The above-mentioned article using the composition of the present invention can be produced by a usual method for producing a thermoplastic resin or an elastomer, such as extrusion molding, injection molding, blow molding or compression molding.

(Example) Hereinafter, the present invention will be described more specifically with reference to Examples. The parts and% in the examples, comparative examples and reference examples are based on weight unless otherwise specified.

Examples 1 to 4 Epichlorohydrin homopolymer rubber (Nippon Zeon Co., Ltd.)
Zeklon 1000), liquid epichlorohydrin homopolymer (Hydrin 10 × 2 from Goodrich Chemical Company, number average molecular weight 3400), magnesium oxide, and 2,4,6-trimercapto-S-triazine were used in Example 1 of Table 1. Mixing was carried out with a low-temperature roll at the mixing ratios described in 4 to 4 to prepare a masterbatch.
On the other hand, Nylon-11 resin was melted in an amount shown in Table 1 with a Labo Plastomill (manufactured by Toyo Seiki) set at 200 ° C and 100 rpm,
The first-stage dynamic vulcanization was carried out by charging the above masterbatch and kneading for about 10 minutes. Then N, N ′
-Dicinnamylidene-1,6-hexanediamine was added in the amount shown in Table 1, and kneading was continued for about 17 minutes to allow dynamic vulcanization to proceed sufficiently.

The obtained composition was rolled out on a roll at 180 ° C., allowed to cool, and then molded into a sheet having a thickness of 2 mm by a heating press. The mechanical properties of the sheet-like composition thus obtained were measured according to JIS K
It measured according to 6301. Regarding the permeation amount of the fluorine-based organic compound gas, 10 g of R-22 was injected into a permeation cell made of stainless steel (SUS-304) having an internal volume of 20.3 ml, and the sheet-shaped composition (thickness 0.6 mm, diameter 38.5 mm). After the cell was kept at 30 ° C. for 24 hours, the weight was measured and the weight change was determined. The extrusion moldability was evaluated by using a test extruder (manufactured by Toyo Seiki Co., Ltd., screw diameter 20 mm, die diameter 5 mm) to extrude the tube at a molding temperature of 230 ° C. and a withdrawal speed of 6 m / min, and to judge the appearance of the molded product. As the appearance judgment standard, the unevenness and gloss of the tube surface were evaluated in the following 5 grades.

Melting point: Judgment criteria 5: Skin is extremely smooth and shiny 4: Skin is smooth but not shiny 3: Fine skin is rough 2: Remarkably rough skin 1: Large wavy rough skin The results are shown in Table 1.

Comparative Examples 1 to 6 The compositions of Comparative Examples 1 to 6 were prepared in the same manner as in Examples 1 to 4, and the physical properties were evaluated. The results are shown in Table 1.

When Example 3 and Comparative Example 5 in Table 1 are compared (the amount of the liquid polymer and the amount of the plasticizer used are the same), when the liquid polymer is used instead of the plasticizer, the tensile strength and the fluorine-containing organic compound are reduced. It can be seen that the compound gas permeability is remarkably improved, the extrusion moldability is remarkably improved, and the thermoplasticity is excellent. Further, from the comparison between Example 4 and Comparative Example 8 (the amount of the liquid polymer and the amount of the plasticizer used are the same), the use ratio of nylon is at least, and the use ratio of the nylon is within the range of the present invention by using the liquid polymer. It can be seen that not only the tensile strength and the freon gas permeation resistance equivalent to those in the case of exceeding, but also the excellent thermoplastic moldability are provided.

Claims (1)

[Claims] 1. A polyamide resin of 30 to 70% by weight, (B) epichlorohydrin rubber of 70 to 30% by weight, and 3 to 30% by weight of the total of (C) (A) + (B). ,
An elastomeric composition comprising a liquid epichlorohydrin having a number average molecular weight of 5,000 or less, wherein epichlorohydrin rubber is dispersed as crosslinked rubber particles in a polyamide resin.