JPS5946271B2 - Futsuso Gomuso Seibutsu - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to fluororubber compositions such as vinylidene fluoride-hexafluoropropene di-copolymer, vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer, etc. .

In particular, the objective is to provide a composition that is scorch resistant, has excellent workability and storage stability, and has excellent vulcanization reactivity. It is known that the aforementioned fluororubbers can be vulcanized, for example with polyamines [see, for example, Industrial, & Engineering, Chemistry, Vol. 49, 16].
87 (1957)], but when a polyamine was used, the composition had the disadvantage of causing scorch during kneading or molding of the fluororubber.

Therefore, research was carried out on vulcanizing agents that could solve this scorch problem, and carbamates such as hexamethylene diamine carbamate [Rubber World,
Vol. 37, p. 250 (1957)] and Schiff bases such as N-N-dicinnamylidene-l,6-hexamethylene diamine (British Patent No. 838,281) have scorch resistance. was revealed.

However, as described in the left column of page 1 of the British patent, when hexamethylene diamine carbamate is used, it cannot be said that it still has sufficient scorch resistance, and vulcanization reaction occurs during molding. As a result, the mold flow within the mold is inhibited at an early stage, which is a drawback. On the other hand, N-N'-dicinnamylidene-l ・
When using a Schiff base type vulcanizing agent such as 6-hexamethylene diamine, the vulcanization reactivity is lower than that of a hexamethylene diamine carbamate type vulcanizing agent as described in Rubber World. is small, vulcanization at high temperature is practically required, and the vulcanized rubber thus obtained still has a large compression set.

In addition, N・N'-dicinnamylidene-1,6-hexamethylene diamine has a unique odor, and it emits an intolerable odor during roll kneading or vulcanization reaction. Sulfur rubber generates tar-like volatile matter, which causes it to stick to the mold, staining the mold, and making the vulcanized rubber skin rough. However, as a result of various studies conducted by the present inventors in order to overcome the drawbacks of the prior art as described above, they discovered that the fluorate of aliphatic diamine can be effectively used as a vulcanizing agent for fluororubber, and based on this, As a result, we have completed the present invention.

That is, the present invention is a fluororubber composition comprising a fluororubber mixed with an acid acceptor, a fluoride salt of aliphaateisocdiamine as a vulcanizing agent, and, if necessary, a filler. The vulcanizing agent of the present invention has the above-mentioned N-N-
Compared to disinnamylidene 1,6-hexamethylene diamine, it has a much higher vulcanization rate, does not exhibit the same scorch properties as hexamethylene diamine carbamate, and has no odor, making it highly workable and economical. Moreover, the properties of the vulcanized rubber obtained from the composition of the present invention are comparable to those of conventional products.

Furthermore, when the vulcanization reaction is carried out using the vulcanizing agent of the present invention, there is no stickiness or staining of the mold, and the resulting vulcanized rubber has an excellent skin gloss. In carrying out the present invention, the range of fluororubbers that can be used is extremely wide, such as vinylidene fluoride, hexafluoropropene, pentafluoropropene, trifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, vinyl fluoride, Copolymers with one or more fluorine-containing olefins such as perfluoromethyl vinyl ether and perfluoropropyl vinyl ether are used.

Preferred among these are vinylidene fluoride-hexafluoropropene di-copolymer and vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer, and of particular interest are vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer. A binary copolymer in which the component ratio with hexafluoropropene is 92:8 to 55:45 in molar ratio, and the component ratio of vinylidene fluoride, hexafluoropropene, and tetrafluoroethylene is 86:9:5 in molar ratio, 60:35:5, 28:42:3
It is a terpolymer within the composition range connecting the four points on the triangular graph of 0, 54:16:30 with a straight line.

In addition to these copolymers, copolymers containing small amounts of vinyl compounds, olefin compounds, diene compounds, or other α/β monoethylenically unsaturated carboxylic acids can also be used effectively. The amount of the vulcanizing agent, that is, the fluorate of aliphatic diamine, added to such fluoro rubber is 0.5 to 10 parts per 100 parts (parts by weight, same hereinafter) of the fluoro rubber, especially 1
It is appropriate to set the amount to about 5 parts.

If the amount of the vulcanizing agent added is smaller than the above range, vulcanization will be insufficient, while if it is larger, the vulcanization reaction will proceed too much and the rubbery properties will tend to be lost. The fluorate salt of the aliphatic diamine used in the present invention preferably has the general formula H2N-R-NH2.2HF (wherein R is an alkylene group having 4 to 15 carbon atoms).
Specific examples include tetramethylene diamine fluoroate, hexamethylene diamine fluoroate, decamethylene diamine fluoroate, and the like.

In addition, as acid acceptors, magnesium, calcium, lead,
Basic 2fifJ metal oxides such as zinc and barium, hydroxides, phosphates, carbonates, and weak acid salts such as stearic acid and phosphorous acid are used. In the present invention,
Although sufficient effects can be achieved by using only the above additives, fillers and reinforcing agents such as carbon black, silica, clay, diatomaceous material, and talc can be added as necessary. As long as it does not depart from the spirit of the present invention, a small amount of one or more conventionally known vulcanizing agents may be blended. Furthermore, a plasticizer and a coloring agent can also be added. The composition thus obtained can be vulcanized by a conventional method, such as a method in which the composition is kneaded with rolls, placed in a mold, pressurized, and subjected to primary vulcanization, and then secondary vulcanization.

In general, the conditions for primary vulcanization are a temperature of 100 to 200°C, a time of 10 to 180 minutes, and a pressure of 20 to 100k9/crAG.
The temperature is 300° C. and the time is from about 0 to 30 hours. Other vulcanization methods include vulcanization after preforming such as extrusion, ketones such as methyl ethyl notone, acetone, and cyclohexanone, ethers such as methyl ethyl ether, diethyl ether, and dioxane, methyl acetate, A solution or dispersion using one or more esters such as ethyl acetate and ethyl propionate as a medium is prepared, and this is applied to paper, fibers, films, sheets, boards, tubes, pipes, tanks, and large containers. Any method of coating and vulcanizing the surface of a molded article or the like can be effectively implemented. The vulcanized rubber obtained from the composition of the present invention has excellent heat resistance, cold resistance, chemical resistance, etc., as well as fluoro rubber products obtained using conventionally known vulcanizing agents. Since the above-mentioned composition exhibits good processability which cannot be obtained by conventionally known vulcanizing agents, its industrial and economic value is extremely large.

Next, the composition of the present invention will be explained with reference to Examples.

Examples 1 to 4 and Comparative Examples 1 to 4 As shown in Table 1 (Examples 1 to 4), 100 parts of fluororubber, a vulcanizing agent, medium thermal carbon,
The mixture was kneaded at room temperature on a rubber roll while sequentially adding predetermined amounts of magnesium oxide and calcium hydroxide, and left overnight to ripen.

After that, it was rewired and put into a mold, and the temperature was 160℃ and it was 35k9/cr! Primary vulcanization was carried out by treating under iG pressure for 20 minutes, and molded into sheets and blocks, respectively.

Then, it is taken out from the mold and heated in a furnace at a temperature of 200℃ for 2 hours.
The 100% modulus, tensile strength, elongation, and hardness of the vulcanized rubber sheet obtained by vulcanizing for 4 hours to complete the secondary vulcanization, and the compression set of the block were determined according to JIS K6301. It was measured.

In addition, a vulcanization test was conducted on the vulcanized composition using a JSR type Cyulastometer Model 2 (manufactured by Japan Synthetic Rubber Co., Ltd.) at the temperatures listed in Table 1, and the minimum viscosity,
The degree of vulcanization, induction time, appropriate vulcanization time, and vulcanization rate were determined.

For comparison, Comparative Examples 1 to 4 were tested in the same manner as Examples 1 to 4.

The above results are shown in Table 1.

In addition, as for the fluoro rubber, the molar ratio of each component of vinylidene fluoride hexafluoropropene is 78:
Binary copolymer of 22 [binary system, intrinsic viscosity (limiting viscosity in methyl ethyl ketone solvent at 35°C, same hereinafter) [η]: 0.79] and vinylidene fluoride hexafluoropropene-tetrafluoroethylene The molar ratio of each component is 67.5:15. In the case of hexamethylene diamine carbamate, as shown in Table 1, the vulcanization reaction was Because it was too early, scorch occurred, and as a result, mold flow within the mold was inhibited at an early stage, making it impossible to obtain a molded product with a regular shape.

On the other hand, in the case of N-N-dicinnamylidene-1,6-hexamethylenediamine, the vulcanization reaction is slow, the compression set is large, and as mentioned above, the foul odor and mold stain are severe, and the skin of the vulcanized rubber is The luster has deteriorated. Further, in the case of hexamethylene diamine hydrochloride, it was not vulcanized. On the other hand, the vulcanizing agents of the present invention, such as hexamethylene diamine fluoride and decamethylene diamine fluoride, have moderate vulcanization reactivity, and the resulting vulcanized rubber has well-balanced properties and can be said to be a particularly rubber-like rubber.

Claims (1)

[Claims] 1. A fluororubber composition comprising a fluororubber mixed with an acid acceptor, a hydrofluoric acid salt of aliphatic diamine as a vulcanizing agent, and, if necessary, a filler.