JPH0726020B2 - Rubber-like resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rubber-like resin composition, and more specifically, it is formed by mixing a specific thermoplastic resin and two specific rubbers in a specific state, The present invention relates to a rubber-like resin composition which can be easily molded by a method similar to that of a usual thermoplastic resin, has rubber-like elasticity, and has improved some of the defects of rubber, and a method for producing the same.

(Prior Art and Problems) Rubber is used in a very wide field because of its excellent elasticity and flexibility. However, in order to impart these properties to rubber, an intermolecular crosslinking process generally called vulcanization is necessary, which is one of the major causes of poor moldability of rubber.

As one of the attempts to improve the moldability, mixing rubber and thermoplastic resin makes it flow like a normal thermoplastic resin by simply applying heat and then cooling and solidifying it to obtain a desired shape. There are many proposals for obtaining a rubber-like composition that can be obtained.

For example, Japanese Examined Patent Publication No. 55-14096 proposes an elastomer plastic composition comprising a polyamide and a crosslinked butadiene polymer, but this composition is inferior in weather resistance and ultraviolet resistance due to the butadiene polymer and is not suitable for use. There were drawbacks that were limited.

Further, JP-A-57-5573 proposes a composition comprising polyamide and cured epichlorohydrin rubber.
I was not satisfied with the flexibility.

Further, in JP-A-59-49246, a composition obtained by mixing a polyamide, a specific nitrile rubber and a curing agent is further described in JP-A-59-49246.
168056, JP-A-60-96630, JP-A-60-96631, etc. propose compositions containing a polyamide, a specific nitrile rubber, a specific epichlorohydrin and a curing agent, respectively, but the dispersibility of the rubber is poor. Moreover, the flexibility and elasticity were insufficient.

Therefore, as a result of earnest research to solve these technical problems, the present inventors have found that a composition comprising a polyamide resin, a crosslinked polyoctenylene rubber, and a crosslinked nitrile-butadiene rubber is easy to mold, and is resistant to gasoline. It has been found that the drawbacks of rubber such as resistance, chemical resistance, weather resistance, ozone resistance, and ultraviolet resistance are improved, and the rubber has sufficient flexibility and elasticity. Furthermore, it was found that this rubber-like resin composition can be easily obtained by kneading a polyamide resin, a polyoctenylene rubber, and a nitrile-butadiene rubber, and kneading the two rubbers together under the condition that they are cross-linked. Based on this, the present invention has been completed.

(Means for Solving Problems) That is, the present invention is a rubber-like resin composition in which a polyamide resin is blended with a crosslinked polyoctenylene rubber and a crosslinked nitrile butadiene rubber.

Further, it is a method for producing a rubber-like resin composition, which comprises a step of kneading the polyamide resin in a condition where the polyamide resin is melted and the rubber is melt-crosslinked when the polyamide resin is mixed with the polyoctenylene rubber and the nitrile butadiene rubber.

The polyamide resin in the present invention means caprolactam,
Lactams such as lauryllactam, ω-aminocarboxylic acids such as 12-aminododecanoic acid and 11-aminoundecanoic acid, dicarboxylic acids such as adipic acid and hexamethylenediamine, dodecanedioic acid and hexamethylenediamine, and isophthalic acid and isophoronediamine. A resin obtained by condensation polymerization of diamine or the like is exemplified. In addition, this polyamide resin is obtained by condensation polymerization of caprolactam and lauryllactam or hexamethylenediamine, dodecanedioic acid and two or more isophthalic acid lactams, ω-aminocarboxylic acid, diamine and dicarboxylic acid. As a matter of course, copolymer nylon, and those referred to as polyether amides, polyester amides or polyether ester amides containing lauryl lactam and tetramethylene glycol as main components are also included.

The polyoctenylene rubber used in the present invention is obtained by dimerizing butadiene and then metathesis-polymerizing octenylene, which is a cyclic compound having one double bond left by hydrogenation. Among them, the trans content is 52 to 90
%, The crystallinity in the range of 5 to 70% is preferably used.

Further, the nitrile butadiene rubber used in the present invention,
It is obtained by copolymerizing acrylonitrile and butadiene, and among them, those having a bound nitrile amount of 10 to 50% by weight are preferably used.

Dyes and pigments, various stabilizers, fillers, plasticizers, oils and the like can be added to the polyamide resin in the present invention.
The polyoctenylene rubber and nitrile butadiene rubber used in the present invention include carbon black, zinc white,
Fillers such as magnesium oxide, stearic acid, silica,
Oils such as extender oil, various stabilizers such as anti-aging agents,
A lubricant or the like can be added.

The rubber-like resin composition in the present invention can be obtained by kneading under a condition that the polyamide resin melts and the polyoctenylene rubber and the nitrile butadiene rubber melt-crosslink. In this case, the polyoctenylene rubber and the nitrile butadiene rubber can be self-crosslinked by heat, but preferably they are heated as a uniform mixture with a crosslinking agent or a crosslinking accelerator. Examples of the crosslinking agent include peroxides, sulfur, organic sulfides, bismaleimides, and epoxy compounds, and examples of the crosslinking accelerator include thiazoles, thiurams, guanidines, and the like. The heating temperature is preferably 150 to 270 ° C. from the viewpoint of easiness of kneading, crosslinking reaction rate, and deterioration prevention.

Further, in order to efficiently carry out the crosslinking reaction, a polyoctenylene rubber or / and a nitrile butadiene rubber are preliminarily mixed with a crosslinking agent or / and a crosslinking accelerator, etc.
It is also possible to perform uniform mixing at a low temperature of 0 ° C. or lower and then melt-mix with the polyamide resin to complete the crosslinking reaction.

The kneading of the polyamide resin and the polyoctenylene rubber and the nitrile butadiene rubber in the present invention is performed by a kneader such as a Banbury mixer, a roll, an extruder, etc.
In order to prevent the oxidative deterioration of the polyamide resin and the rubber, it is more preferable to knead them in a state in which air is blocked, such as in a nitrogen atmosphere.

The method for obtaining the composition of the present invention is characterized in that the polyoctenylene rubber and the nitrile butadiene rubber are kneaded while being crosslinked, and preferably the kneading should be continued until the crosslinking of the rubber is almost completed. If the kneading is stopped before the cross-linking progresses, the moldability becomes difficult due to poor dispersibility, and at the same time, the flexibility and elasticity are not observed due to insufficient cross-linking.

(Effect of the invention) The rubber-like resin composition obtained in the present invention is flexible and rich in elasticity, excellent in gasoline resistance, chemical resistance, ozone resistance, weather resistance, ultraviolet resistance, etc. Since it can be easily molded like a plastic resin, it is used, for example, by extrusion molding to form a tube, as a wire coating, or molded into a flexible sheet. Furthermore, it can be easily molded and used for shoes or clips by injection molding, compression molding or the like. Alternatively, it is used after being molded into a diaphragm, a bellows or the like by blow molding.

(Examples) The present invention will be described in detail below with reference to Examples.

Examples 1 to 5 Nylon 12 (Daicel Hüls, Daiamide L1940), polyoctenylene rubber (Hüls VESTENAMER8012) and nitrile butadiene rubber (JSR N-221H) in the proportions shown in Table 1 were used as the rubber. 2 parts by weight of metaphenylene bismaleimide, 0.2 parts by weight of lauroyl peroxide, 5 parts by weight of zinc oxide and 2 parts by weight of stearic acid were added to a Henschel mixer all at once and dry blended, and then made by Toshiba. 220 in 55mm twin screw extruder
After extruding at ℃, it was pelletized by a pelletizer. The pellets were molded into a tensile test dumbbell piece and a bending test piece by an ordinary injection molding machine. Using these test pieces, the tensile strength and elongation and the flexural modulus were determined, and it was found that they showed good appearance and physical properties. Using this test piece, 60m between chucks in an atmosphere of 40 ℃ and 50ppm of ozone
Dynamic elongation was performed with a stroke of 0 to 5 mm at a cycle of 30 rpm at m, and the time until the sample broke was measured, and this value was defined as ozone resistance. The results are shown in Table 1.

Example 6 Nylon 6 (Amilan CM1021 manufactured by Toray Industries), the ratio of polyoctenylene rubber and nitrile butadiene rubber shown in Table 1, and 5 parts by weight of metaphenylene bismaleimide and 0.5 parts by weight of benzothiazole per the total compounding amount of the rubber. The disulfide was charged into a HAAKE Rheocord set at 250 ° C., and kneading was performed by setting the rotor rotation speed of the Rheocord to 50 rpm. Observing the torque meter attached to the Leo cord, the torque increased little by little after the kneading was started.
The maximum value was shown in minutes. After reaching the maximum torque, the kneading was continued for about 8 minutes to allow the crosslinking reaction to sufficiently occur, and then the contents were taken out. When this reaction product was press-molded, a sheet could be molded as easily as a thermoplastic resin. From this sheet, a tensile dumbbell piece and a bending test piece were punched out, and the tensile strength / elongation and bending elastic modulus were determined, and it was found that they showed good physical properties. Also, using this test piece, the space between chucks should be 6 in an atmosphere of 40 ℃ and 50ppm of ozone.
Dynamic elongation was performed at 0 mm and a stroke of 0 to 5 mm at a cycle of 30 rpm, and the time until the sample broke was measured, and this value was defined as ozone resistance. The results are shown in Table 1.

Examples 7 and 8 In Examples 1 to 5, instead of nylon 12, nylon 612 (Daiamide D180 manufactured by Daicel Hüls) was used.
0), Example 1 except that polyamide elastomer (Daiamide PAE E40 manufactured by Daicel Hüls) is used.
Kneading and molding were carried out in the same manner as in Nos. 5 to 5, and the tensile test, bending test and ozone resistance were examined. The results are shown in Table 1.

Example 9 Polyoctenylene rubber in the proportions shown in Table 1 (manufactured by Huls)
VESTENAMAER 6213) and nitrile butadiene rubber, and 5 parts by weight of metaphenylene bismaleimide, 0.5 parts by weight of lauroyl peroxide and 5 parts by weight of the total amount of the rubber compounded.
By weight, zinc oxide was kneaded in a 30 mm twin-screw extruder manufactured by Chuo Kikai at 60 ° C., and then pelletized by a pelletizer. The pellets and nylon 12 were blended in a ratio shown in Table 1, melt-kneaded in a 55 mm twin-screw extruder at 220 ° C. while undergoing a crosslinking reaction, and pelletized with a pelletizer. Using these pellets, a tensile dumbbell piece and a bending test piece were molded by an ordinary injection molding machine.
Table 1 shows the results of measuring the tensile strength and elongation, the flexural modulus, and the ozone resistance of these test pieces, and they showed good appearance and physical properties.

Comparative Examples 1 to 3 Using the three types of rubbers shown in Table 1, tensile dumbbell pieces and bending test pieces were molded by a normal injection molding machine. Table 1 shows the results of measurement of tensile strength and elongation, flexural modulus, and ozone resistance using these test pieces. It was revealed that these have poor ozone resistance.

Comparative Examples 4 to 6 In Examples 1 to 5, as shown in Table 1, kneading and molding were performed in exactly the same manner as in Examples 1 to 5 using only one type of rubber among the three types of rubber, and tensile strength and elongation were set. Degree, flexural modulus and ozone resistance were measured. The results are shown in Table 1, and it was revealed that the ozone resistance was inferior.

Claims (2)

[Claims] 1. A rubber-like resin composition comprising a polyamide resin and a crosslinked polyoctenylene rubber and a crosslinked nitrile butadiene rubber. 2. The method according to claim 1, which comprises a step of kneading the polyamide resin in a condition that the polyamide resin is melted and the rubber is melt-crosslinked when the polyoctenylene rubber and the nitrile butadiene rubber are blended with the polyamide resin. The method for producing the rubber-like resin composition according to claim 1.