JPS6148535B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a chloroprene rubber composition that can be vulcanized at room temperature and pressure. Conventionally known methods for crosslinking chloroprene rubber include metal oxide vulcanization, sulfur vulcanization, and amine vulcanization. However, all of these conventional and widely practiced methods require a high temperature of 100° C. or higher for crosslinking, and the required crosslinked product cannot be obtained at room temperature and pressure. For example, in the metal oxide vulcanization method using magnesium oxide and zinc oxide, even if a generally known excellent vulcanization accelerator is used in combination, press vulcanization requires heating at 150℃ for 5 to 10 minutes. be. In the case of steam vulcanization, a continuous vulcanizer is used, and the extruded product is introduced into a vulcanization tube and heated with high-temperature, high-pressure steam to perform vulcanization. Alternatively, the material is extruded, covered with tape or lead, placed in a vulcanization pot, and vulcanized by directly introducing high-temperature, high-pressure steam. In any case, these conventional vulcanization methods require heating, which has the drawback of consuming a large amount of thermal energy such as electric heating, high temperature, and high pressure steam. Furthermore, for these conventional vulcanizations, heating press,
This method has the drawback of requiring special manufacturing equipment such as a continuous vulcanizer and a vulcanizing pot, which increases equipment costs. In order to eliminate the above-mentioned drawbacks, the applicant has
No. 55-70192 was proposed. This prior invention involves reacting chloroprene rubber with an organic silane having at least one amino group or mercapto group to obtain a crosslinkable polychloroprene, which is then brought into contact with moisture in the presence of a silanol condensation catalyst to be crosslinked. It is characterized by the fact that chloroprene rubber can be vulcanized at room temperature and pressure. However, when carbon black is blended into the rubber composition, the Mooney viscosity of the rubber composition increases significantly, making extrusion processing difficult. In order to overcome this drawback, conventionally used rubber softeners such as process oils were blended, but the chloroprene rubber compositions containing rubber softeners had a lower Mooney viscosity and were difficult to process. Although it has improved properties and can be vulcanized at room temperature and pressure, the physical properties of the vulcanizate are significantly reduced, which is a major drawback in practical use. This invention was made in view of the above circumstances,
The purpose of the present invention is to provide a chloroprene rubber composition that can be vulcanized at normal temperature and pressure, has good processability, and has excellent physical properties of the vulcanizate. It is characterized by blending liquid chloroprene rubber and an amino group-containing organic silane compound with chloroprene rubber. This invention will be explained in detail below. The chloroprene rubber used in this invention is mainly polychloroprene obtained by polymerizing chloroprene, and is commonly used with a molecular weight of 20,000 to 200,000.Here, carbon black, calcium carbonate, etc. It contains a filler. Liquid chloroprene is first mixed into chloroprene rubber. This liquid chloroprene is represented by the following formula obtained by polymerizing 2-chlorobutadiene-1, 3, and has a functional group A bonded to the end of the molecule. Functional group A ――SH,

[Formula]-COOH,

[Formula] - There are types such as OH. The molecular weight of liquid chloroprene is quite small, 1500 to 5000, and it is liquid at room temperature, and its viscosity is 3×
10 ⁴ to 5×10 ⁵ cps. Liquid chloroprene is blended in an amount of 5 to 50 parts by weight per 100 parts by weight of chloroprene rubber. If the amount is less than 5 parts by weight, the desired effect will not be obtained, and if it exceeds 50 parts by weight, the physical properties of the resulting chloroprene composition will be markedly deteriorated, which is disadvantageous, and the amount is preferably 10 to 30 parts by weight.
This liquid chloroprene lowers the Mooney viscosity of the chloroprene rubber composition and improves processability such as extrusion processability. In addition, since liquid chloroprene has the same molecular structure as chloroprene rubber, it is vulcanized with an amino group-containing organic silane compound, which will be described later.
Since it is cured, there is almost no deterioration in the physical properties of the chloroprene rubber composition after vulcanization. Then, an amino group-containing organosilane compound is added. This amino group-containing organosilane compound has the general formula RR′ _o SiX _3-o (wherein R is an organic group bonded to silicon via a silicon-to-carbon bond and having 20 or more carbon atoms, The R group is composed of carbon, hydrogen, nitrogen and optionally oxygen and contains at least one amino group, R' is a monovalent hydrocarbon group having 1 to 9 carbon atoms, and X is 1 or an alkoxyalkoxy group having 6 to 6 carbon atoms, or an oxime group having up to 14 carbon atoms, and n is 0 or 1), and more specifically, R is an organic group as described above. group containing at least one amino group. The amino group includes primary, secondary and tertiary amino, and also includes imino. Therefore, examples of R groups are -(CH ₂ ) ₃ NHCH ₂ CH ₂ NH ₂ , -
(CH ₂ ) ₄ NHCH ₂ CH ₂ NH ₂ , -
(CH ₂ ) ₃ NHCH ₂ CH ₂ NHCH ₂ CH ₂ NH ₂ , -
CH ₂ CHCH ₃ CH ₂ NH (CH ₂ ) ₆ NH ₂ , -
(CH ₂ ) ₃ NH ₂ , - (CH ₂ ) ₄ NHCH ₃ , -
(CH ₂ ) ₁₁ NH ₂ , ―NHSi(CH ₃ ) ₃ , ―
(CH ₂ ) ₃ NHCH ₂ CH ₂ NHCO・NH ₂ , and

〔Example〕

Chloroprene rubber compositions having the amounts shown in Table 1 were prepared and roll-kneaded at about 60°C to 70°C for 10 minutes. Mooney viscosity of this (ML ₁₊₄ )
was measured at 100℃. The above-mentioned kneaded product was supplied to an extruder and extrusion coated onto a 5.5 mm ² conductor at 80° C. to produce a chloroprene rubber-coated electric wire. The physical properties of the chloroprene rubber layer of this electric wire were measured by vulcanizing it by immersing it in water at room temperature for one day, and by leaving it in the atmosphere at room temperature and pressure for 5 days to be vulcanized. The results are shown in Table 3. In addition, a chloroprene rubber composition having the formulation shown in Table 2 was prepared and roll-kneaded at about 60°C to 70°C for 20 minutes. The Mooney viscosity (ML ₁₊₄ ) of this is
Measured at 100℃. The above-mentioned kneaded product was supplied to an extruder and extrusion coated onto a 5.5 mm ² conductor at 80° C. to produce a chloroprene rubber-coated electric wire. This electric wire was wrapped with cloth tape, placed in a vulcanizing pot at 150°C, and heated for 15 minutes to vulcanize it. The physical properties of the chloroprene rubber layer of this product were measured. The results are also shown in Table 3.

【table】

【table】

【table】

【table】

[Table] As is clear from Table 3, by blending liquid chloroprene, the Mooney viscosity can be made almost the same as that of a composition containing a conventional metal oxide vulcanizing agent. Furthermore, it can be seen that vulcanizates that are vulcanized by leaving them in moisture or the atmosphere have almost the same physical properties as vulcanizates obtained by conventional heat vulcanization methods. . As explained above, the chloroprene rubber composition of the present invention is a mixture of chloroprene rubber, liquid chloroprene, and an amino group-containing organic silane compound, and can be vulcanized with the amino group-containing organic silane compound at room temperature and pressure. . In addition, since liquid chloroprene is blended, processability such as roll kneading and extrusion processing is improved, and since liquid chloroprene is vulcanized in the same way as chloroprene rubber by an amino group-containing organosilane compound, the physical properties of the vulcanized product are improved. becomes excellent. Therefore, there is no need for conventional vulcanization equipment, no need for thermal energy, and there are advantages such as a chloroprene rubber vulcanizate with excellent physical properties can be provided at a low manufacturing cost.

Claims (1)

[Claims] 1. A chloroprene rubber composition obtained by blending liquid chloroprene rubber and an amino group-containing organic silane compound with chloroprene rubber.