JPH0138811B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention is a novel processing aid for rubber, more specifically, it is effective in improving the physical properties of rubber, shortening rubber kneading time, saving energy, and improving processability such as increasing extrusion speed. A rubber characterized by the addition of one or more selected from propylene glycol unsaturated fatty acid esters, polyglycerin unsaturated fatty acid esters, and pentaerythritol unsaturated fatty acid esters having one or more hydroxyl groups. The present invention relates to a blended composition. [Problems to be solved by conventional technology and inventions] In recent years, as the uses of rubber products have increased and the range of use has expanded, there has been a limit to the use of conventional general-purpose rubber. Nitrile rubber, ethylene-propylene rubber,
Hypalon, silicone rubber, fluorine rubber, etc. are forced to be used. However, although the use of these products has produced products with quite satisfactory physical and chemical properties,
Regarding its processability, it cannot be overlooked that it has a drawback that cannot be removed from the category of special rubber. Furthermore, due to the energy situation in recent years, the rubber processing industry, which uses a large amount of energy, naturally has a strong interest in energy conservation. Therefore, efforts are being made to improve processability and save energy. Improvements in processing machinery, synthesis of rubber polymers, improvements by adding third components, etc. are being considered. Although considerable results have been obtained, each method has its advantages and disadvantages, and no definitive method has been found. [Means for solving the problem] Therefore, the present inventors have conducted extensive research with the aim of improving it by adding a third component.
1.0 to 10 parts by weight of one or more selected from propylene glycol unsaturated fatty acid esters, polyglycerin unsaturated fatty acid esters, and pentaerythritol unsaturated fatty acid esters having hydroxyl groups of 5 or more are added to 100 parts by weight of rubber. The present inventors have discovered that, by doing so, conventional physical properties can be maintained or improved, and workability can also be greatly improved, leading to the present invention. The third component for improving processability of the present invention has a carbon number of 10 to 24.
unsaturated fatty acids such as lauroleic acid, oleic acid, elaidic acid, erucic acid, linoleic acid, linoelaidic acid, eleostearic acid, linolenic acid, or mixed fatty acids thereof, propylene glycol, polyglycerin, An ester compound obtained by a dehydration condensation reaction with a polyhydric alcohol such as pentaerythritol, which has at least one hydroxyl group in the molecule. Among the one or more selected from propylene glycol unsaturated fatty acid ester, polyglycerin unsaturated fatty acid ester, and pentaerythritol unsaturated fatty acid ester, which have at least one or more hydroxyl group in the molecule as used in the present invention, Esters of saturated fatty acids of 30% or less may be mixed, but for effectiveness it is better to have as little as possible. The unsaturated fatty acids used should be determined in consideration of the aging properties of the rubber product and the bleeding and frosting of one or more types selected from propylene glycol unsaturated fatty acid esters, polyglycerin unsaturated fatty acid esters, and pentaerythritol unsaturated fatty acid esters. The fatty acid chain length has 1 to 2 saturated bonds, and as mentioned above, it is desirable to use mixed fatty acids or animal and vegetable oils that are low in saturated fatty acids. The amount of one or more selected from propylene glycol unsaturated fatty acid esters, polyglycerin unsaturated fatty acid esters, and pentaerythritol unsaturated fatty acid esters having at least one or more hydroxyl group in the molecule is the amount used in rubber.
The amount is 1.0 to 10 parts by weight per 100 parts by weight, and if it is less than 1.0 parts by weight, the effect of improving workability is insufficient.
If it exceeds 10 parts by weight, it is unfavorable in terms of the effect of improving rubber physical properties and economical efficiency. One or more selected from the above propylene glycol unsaturated fatty acid ester, polyglycerin unsaturated fatty acid ester, and pentaerythritol unsaturated fatty acid ester must have at least one hydroxyl group in the molecule, and extrusion The more hydroxyl groups in the molecule, the better for improving processability such as increasing speed. Furthermore, an interesting phenomenon discovered by the present inventors as a favorable phenomenon is that when added to ethylene-propylene rubber, the added component intervenes in the vulcanization reaction without affecting the vulcanization system, increasing the tensile strength and tear strength of the vulcanized rubber. The advantage is that a vulcanized rubber product with improved elongation and no bleeding can be obtained. As a result of studying the behavior of processability improvers for these various effects, we found that propylene glycol unsaturated fatty acid esters, polyglycerin unsaturated fatty acid esters, and pentaerythritol unsaturated fatty acid esters have at least one hydroxyl group in the molecule. 1 or 2 selected from
It has been found that when the amount of rubber exceeds 100%, a vulcanization reaction occurs at the unsaturated bond and is added to the rubber molecular chain, significantly reducing the amount of bleed to the surface and the amount of solvent extracted. Further, the present inventors investigated natural rubber and vulcanizable synthetic rubber, and found that a similar phenomenon was observed, but the effect was particularly great for ethylene-propylene rubber. Similarly, as a result of examining one or more selected from propylene glycol saturated fatty acid ester, polyglycerin saturated fatty acid ester, and pentaerythritol saturated fatty acid ester, which have at least one or more hydroxyl group in the molecule, it was found that 100 parts by weight of rubber When 2.5 parts by weight or more is added, significant frosting is observed in both unvulcanized rubber and vulcanized rubber, which not only leads to a decrease in the product quality of vulcanized rubber products, but also has an adverse effect on the physical properties. The rubber processability improver of the present invention may be added after mastication using a Banbury mixer, kneader, or kneading roll or at the same time as various additives without any effect. In addition, if mastication is not performed, it can be omitted and added in the same manner to save energy or shorten the kneading time during kneading.Furthermore, in the extrusion process of this compounded unvulcanized rubber, the extrusion speed can be increased and the surface Not only is it easy to improve properties, but it is also possible to improve physical properties. In the rubber composition of the present invention, synthetic rubbers include styrene-butadiene copolymer rubber, polybutadiene rubber, polyisoprene rubber, ethylene-propylene copolymer rubber, acrylonitrile-butadiene copolymer rubber, butyl rubber, chloroprene rubber, etc. It can be applied to all rubbers, and can be applied to both sulfur vulcanization and peroxide crosslinking. [Examples and Effects of the Invention] The present invention will be explained in more detail using the examples above. Examples 1 to 3 Basic composition Ethylene-propylene copolymer rubber (EPDM, EP-24) 100 parts Carbon black (HAF) 67.5 Zinc white No. 3 5 Stearic acid 1 Process oil 35 Vulcanization accelerator (M) 0.5 Vulcanization Accelerator (TS) 1.5 Sulfur 1.5 Processability improver 5 Based on the above basic formulation, first put 1200g of rubber into a pressure kneader with a volume of 3 and masticate for 3 minutes, then remove the reinforcing agent and additives except for sulfur and vulcanization accelerator. After adding the agent and kneading for 15 minutes, the power consumption was examined. The results are shown in Figure 1. The rubber temperature at the start of kneading was set at 40°C. Kneaded rubber 2mm thick and 10cm wide
After sheeting into continuous sheets, L/D=
Garvey die extrusion was carried out at an extrusion temperature of 94 to 96° C. using a 10/1 extruder with a screw diameter of 2 inches, and the amount of extrusion per unit time was measured. Furthermore, the general physical properties of the vulcanized rubber were measured. The extrusion amount and general physical properties are shown in the table. As comparative examples, tests were carried out using the basic formulation in which the processability improver was omitted and in which 5 parts of process oil was added instead of the processability improver.

【table】

【table】 [Brief explanation of drawings]

FIG. 1 is a chart showing the power consumption when mixing example formulations of the present invention.

Claims (1)

[Claims] 1 Propylene glycol unsaturated fatty acid ester, polyglycerin unsaturated fatty acid ester, and pentaerythritol unsaturated fatty acid ester having at least one or more hydroxyl group in the molecule in 100 parts by weight of natural rubber or synthetic rubber or blend rubber thereof. A rubber compound composition characterized in that 1.0 to 10 parts by weight of one or more selected species is added to significantly improve processability and physical properties.