JPH08143726A - Crosslinkable chlorinated polyethylene composition excellent in flex resistance and processing stability, molded product and boot excellent in durability - Google Patents

Abstract

PURPOSE: To obtain a crosslinkable chlorinated polyethylene composition excellent in flex resistance and processing stability and useful for obtaining automotive boots excellent in durability by mixing a chlorinated polyethylene with specified compounds. CONSTITUTION: This composition is prepared by mixing chlorinated polyethylene with an adduct (A) of 2-anilino-4,6-dithiol-S-triazine to an amine in a molar ratio of 1/0.5 to 1/2.5 and a metal compound (B) acting as an acid acceptor. Examples of the starting polyethylenes of the chlorinated polyethylene include an ethylene homopolymer and a copolymer of ethylene with an α-olefin or a copolymerizable polar monomer. The chlorine content of the chlorinated polyethylene is desirably 25-50wt.%. The amounts of components A and B are desirably 0.1-20 pts.wt. and 0.3-30 pts.wt., per 100 pts.wt. chlorinated polyethylene, respectively. The amine in component A is particularly desirably an alicyclic sec. amine.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a chlorinated polyethylene cross-linking composition having excellent flex resistance and processing stability, a molded article obtained by cross-linking the cross-linking composition, and an automobile having excellent durability. Regarding boots.

[0002]

2. Description of the Related Art As a chlorinated polyethylene cross-linking composition using a triazine-based vulcanizing agent, Japanese Patent Publication No. 54-15458.
JP-A-4-151072, JP-A-4-15207
The cross-linked composition shown in Japanese Patent No. 27945 is known, and the cross-linked composition is excellent in mechanical strength, heat resistance and ozone resistance, and is widely used as a rubber material for automobiles and various industries.

JP-B-54-15458 is selected from mercaptotriazines, salts with secondary or tertiary amines and their carboxylic acids, salts with mercaptothiadiazoles and salts with dithiophosphoric acids. A cross-linking composition composed of a compound and a metal compound has been proposed. Japanese Patent Laid-Open No. Hei 4
In JP-A-151072, mercaptotriazines, amines or adducts of amines, etc., to chlorinated polyethylene,
A "joint boot excellent in cold resistance" formed by mixing a metal compound has been proposed. In addition, JP-A-4-22794
No. 5, gazette discloses a vulcanized composition having a high modulus of vulcanizate and excellent vulcanization adhesion to a metal. It has been proposed to incorporate a dicyclohexylamine salt of triazine.

[0004]

However, although these crosslinked compositions and molded articles obtained by crosslinking the crosslinked compositions have high physical properties, there is a problem in the processing stability of these crosslinked compositions. In addition, a molded product obtained by crosslinking the crosslinking composition has a problem in flex resistance. Especially constant velocity joint boots, bellows, air intake hose, and other air control hoses, which are parts that transmit vibration,
As the performance of automobiles is improved, it is required to improve flex resistance.

[0005]

As a result of various studies to solve the above problems, the inventors of the present invention have found that chlorinated polyethylene is blended with the compounds (a) and (b) below to obtain flex resistance and processing stability. The present invention has been accomplished by finding out that a chlorinated polyethylene crosslinked composition having excellent properties is obtained. (A) An addition product of 2-anilino-4,6-dithiol-S-triazine and amine, each having a ratio of 1 / 0.5 to 1
/2.5 molar ratio of adduct (b) Metal compound serving as acid acceptor

According to the present invention, as will be apparent from the examples described later, a chlorinated polyethylene cross-linking composition excellent in bending resistance and processing stability, a molded article obtained by cross-linking the cross-linking composition, and durability. Boots with excellent properties can be obtained.

The chlorinated polyethylene used in the present invention is obtained by chlorinating polyethylene powder or particles by an aqueous suspension method, or by chlorinating it in a state of being dissolved in an organic solvent, which is an environmental problem. Alternatively, from the viewpoint of economy, the aqueous suspension method is preferable.

The above-mentioned polyethylene is a homopolymer of ethylene or a copolymer of ethylene and α-olefin,
Furthermore, the copolymer includes a copolymerizable polar monomer.
The copolymerization ratio of these α-olefins or polar monomers is not particularly limited, but a copolymerization ratio of 10% or less of other components is preferable because the strength of the rubber material is easily obtained. α
-Examples of olefins include propylene-1, butene-
1, heptene-1, hexene-1,4-methylpentene-1 and the like. Further, as an example of the polar monomer,
Examples thereof include vinyl acetate, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate and the like.

The chlorine content of the chlorinated polyethylene used in the present invention is preferably 25% by weight to 50% by weight. If it is less than 25% by weight, rubbery properties are lost, which is not preferable. Further, if it exceeds 50% by weight, rubbery properties are lost and cold resistance is deteriorated, which is not preferable. Further, as the rubber material for boots, the chlorine content is preferably 25% by weight to 34% by weight. 25
If it is less than wt%, the oil resistance is insufficient. If it exceeds 34% by weight, the severe cold resistance required for the boot cannot be satisfied. The crystallinity of the chlorinated polyethylene used in the present invention is not particularly limited, but substantially amorphous chlorinated polyethylene is preferable.

The cross-linking component (a) of the present invention is an adduct of 2-anilino-4,6-dithiol-S-triazine and an amine, each having a molar ratio of 1 / 0.5 to 1 / 2.5. It is a thing. 2-anilino-4,6-dithiol-S-
If the amount of amine is less than 0.5 mol based on triazine, vulcanization does not proceed. If it is more than 2.5 mol, the flex resistance is poor.

The amine used in the present invention is preferably an aliphatic or cycloaliphatic primary, secondary or tertiary amine having a pk value of about 4.5 or less. Examples of such amines include n-hexylamine, dibutylamine, tributylamine, trioctylamine, di (2-ethylhexyl) amine, dicyclohexylamine, and the like.

2-anilino-4,6-dithiol-S-
As a method of producing an adduct of triazine and an amine, there is a method of mixing both compounds in an organic solvent, or a method of simply mixing both compounds. After mixing, the amine odor disappears and an adduct is formed. Also 2-anilino-4,
Although the melting point of 6-dithiol-S-triazine is as high as about 260 ° C., it was confirmed that the melting point of the adduct is significantly lowered.

The metal compound serving as the acid acceptor of the crosslinking component (b) of the present invention is one that provides the stability of the crosslinked product and an appropriate crosslinking rate, and specifically, it is a metal of Group II metal of the periodic table. Oxides, hydroxides, carboxylates, silicates, phosphites, borates, oxides of Group IV metals of the periodic table, basic phosphites, basic carbonates, basic carboxylates , Basic sulfite, tribasic sulfate and the like. Specific examples include magnesia, magnesium hydroxide, barium hydroxide, magnesium carbonate, barium carbonate, slaked lime, calcium carbonate, calcium silicate, calcium stearate, zinc stearate, calcium phthalate, calcium phosphite, zinc white, tin oxide. , Litharge, red lead, white lead, dibasic lead phthalate, dibasic lead carbonate, tin stearate, basic lead phosphite, basic tin carbonate, basic lead sulfite,
Examples include tribasic lead sulfate.

The blending amount of the above-mentioned crosslinking component is 100 parts by weight of chlorinated polyethylene (including the above copolymer).
The component (a) is 0.2 to 20 parts by weight, preferably 0.5 to
It is 10 parts by weight, and if it is less than this range, vulcanization is unfavorable and the rubber physical properties are inferior, which is not preferable. If it is more than this range, vulcanization is excessively applied and rubber elasticity is lost, which is not preferable. The component (b) is suitably in the range of 0.3 to 30 parts by weight, preferably 1 to 10 parts by weight. If the amount is less than 0.3 parts by weight, the heat resistance of the vulcanized product is poor, which is not preferable. Even if it exceeds 30 parts by weight, it no longer contributes to the improvement of heat resistance.

Further, in the present invention, it is also possible to use an adduct of the crosslinking component (a) in combination with 2-anilino-4,6-dithiol-S-triazine.

To the crosslinked product of the present invention, various compounding agents which are commonly used in the art, for example, reinforcing agents, fillers, plasticizers, stabilizers, antioxidants, lubricants and flame retardants are added. You are free to do it. Depending on the purpose, a small amount of thermoplastic resin, rubber or the like may be added freely, and short fibers or the like may be added to improve strength and rigidity.

These blends can optionally use ordinary rubber mixing machines such as rolls, kneaders, Banbury mixers, etc., and use the composition of the present invention in blending with various rubber compositions. It is also possible to do so.

In order to produce a cross-linked molded article using the composition of the present invention, it is usually heated to a temperature of 120 ° C to 200 ° C.
The heating time is selected depending on the temperature, but the desired crosslinked product can usually be obtained within a time range of 5 to 60 minutes.
As a method of heat molding, various techniques such as pressure heating with a die, heating with a steam can, air bath, oil bath, infrared rays, microwave, etc. can be used.

[0019]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. In the examples,% is based on weight. (Production of chlorinated polyethylene) 5 kg of polyethylene powder having a density of 0.950 and a melt index of 0.03
70 L of water, a wetting agent, and a dispersant were added to a 00 L glass-lined pressure reactor, and chlorine gas was reacted at 100 ° C to 135 ° C to obtain a chlorinated polyethylene having a chlorine content of 30% (hereinafter, chlorinated polyethylene A). Similarly, a chlorinated polyethylene having a chlorine content of 27%, a chlorine content of 33% and a chlorine content of 45% was obtained (hereinafter, chlorinated polyethylene B, C,
D).

(Synthesis of adduct) 2-anilino-4,6-
Mix 1 mol / 1 mol adduct of dithiol-S-triazine and dicyclohexylamine (hereinafter adduct A) and 1 mol / 2 mol adduct (hereinafter adduct B) in a mortar with a predetermined amount of both compounds. It was synthesized by the method. The melting point of adduct A was about 78 ° C and the melting point of adduct B was about 79 ° C. Further, a 1 mol / 1 mol adduct of trithiocyanuric acid and dicyclohexylamine (hereinafter referred to as adduct C) was synthesized by the same method. The melting point of adduct C was about 189 ° C.
Similarly, 2-dibutylamino-4,6-dithiol-S-
1 mol / 1 with dicyclohexylamine with triazine
A molar adduct (hereinafter adduct D) was synthesized in a similar manner. The melting point of adduct C was about 125 ° C. The melting points of 1 mol / 1 mol adducts of trithiocyanuric acid, 2-dibutylamino-4,6-dithiol-S-triazine and 2-mercaptothiazole with dicyclohexylamine are 330 ° C, 137 ° C or higher and 137 ° C or higher, respectively. is there.

Examples 1 to 5 and Comparative Examples 1 to 6 Kneaded with the compounds shown in Table 1 to obtain uncrosslinked compounded rubber, and
-K-6300 Mooney scorch test was performed, followed by vulcanization at 180 ° C for 10 minutes, and the obtained crosslinked product was subjected to JIS-K-6251 tensile test and JIS-K-626.
A flex crack test of 0 was made. The results are shown in Table 1. In Comparative Example 3, there was an amine odor during processing.

[0022]

[Table 1]

[0023]

[Table 2]

As shown in Table 1, Examples 1 to 1 of the present invention
Sample No. ₅ has a long T _{5 in the} Mooney scorch test and is excellent in processing stability. Even in the flexibility test, crack growth is slow and flex resistance is excellent. As described above, Examples 1 to 5 of the present invention show excellent properties in both processing stability and bending resistance.
There is no other.

That is, in Comparative Example 1, trithiocyanuric acid and 2 were added.
-This is an example of using a mercaptobenzothiazole / dicyclohexylamine adduct, which has the advantage that it does not have an amine odor, but has a short T _{5 and} is inferior in processing stability and inferior in bending resistance.

Comparative Example 2 is an example using a 1/1 molar ratio adduct of trithiocyanuric acid and dicyclohexylamine (adduct C), but it has the same drawbacks as Comparative Example 1.

Comparative Example 3 is an example in which 2-anilino-4,6-dithiol-S-triazine and dicyclohexylamine were added separately, but it is excellent in bending resistance but has odor and T
₅ is short and processing stability is poor.

Comparative Example 4 is an example using 2-anilino-4,6-dithiol-S-triazine and a 2-mercaptobenzothiazole / dicyclohexylamine adduct, which is excellent in flex resistance and odor is also improved. However, as in Comparative Example 3, T ₅ is short and processing stability is poor.

Comparative Example 5 is 2-dibutylamino-4,6-
This is an example of using a 1 mol / 1 mol addition product of dithiol-S-triazine and dicyclohexylamine (addition product D), but it has a short T _{5 and} is inferior in processing stability and inflexibility.

In Comparative Example 6, in order to enhance the dispersibility of the crosslinking component, trithiocyanuric acid and dioctyl sebacate (hereinafter DO
Although S) was mixed at a 1/1 weight ratio and adjusted to particles of 20 μ or less by a three-roll mill, T ₅ was short and processing stability was poor, and bending resistance was also poor.

Further, the crosslinking compositions of Examples 3 and 4 (chlorinated polyethylenes B and C having a chlorine content of 27% and 33%, respectively)
The cold resistance, which is an important characteristic of the constant velocity joint boot, was measured by the low temperature twist test of JIS-K-6261. The results are shown in Table 2. It can be seen that the composition has sufficient cold resistance and is an excellent composition for constant velocity joint boots.

[0032]

[Table 3]

[0033]

EFFECTS OF THE INVENTION The composition of the present invention is excellent in processing stability, and by heat molding, a chlorinated polyethylene rubber-like substance having excellent bending resistance can be obtained. Further, the composition of the present invention is particularly excellent for constant velocity joint boots.

Claims (7)

[Claims] 1. The following (a) is added to chlorinated polyethylene:
Bending resistance, which is characterized by blending the compound of (b),
A chlorinated polyethylene crosslinking composition having excellent processing stability. (A) An adduct of 2-anilino-4,6-dithiol-S-triazine and amine, each of 1 / 0.5 to
Addition product with a molar ratio of 1 / 2.5 (b) Metal compound serving as an acid acceptor 2. The chlorine content of chlorinated polyethylene according to claim 1, which is 25 to 50% by weight, and 0.2 to 20 parts by weight of each of the compounds (a) and (b) relative to 100 parts by weight of chlorinated polyethylene. , 0.3 to 30 parts by weight, and a chlorinated polyethylene crosslinking composition. 3. The method according to claim 1, wherein the amine is a secondary amine.
The chlorinated polyethylene crosslinking composition according to any one of 2 above. 4. The chlorinated polyethylene crosslinking composition according to claim 3, wherein the amine is an alicyclic secondary amine. 5. The chlorinated polyethylene crosslinking composition according to claim 4, wherein the alicyclic secondary amine is dicyclohexylamine. 6. A molded article obtained by crosslinking the chlorinated polyethylene crosslinking composition according to any one of claims 1 to 5. 7. The chlorine content of chlorinated polyethylene is 25-.
A boot having excellent durability, which is 34% by weight and is obtained by crosslinking and molding the chlorinated polyethylene crosslinking composition according to any one of claims 1 to 5.