JPS581141B2 - Chlorosulfonated polyethylene rubber composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chlorosulfonated polyethylene rubber composition that has good surface gloss after hot-flowing or crosslinking and has excellent durability.

Generally, an escalator handrail is constructed by bonding or cross-linking a decorative rubber layer 3 onto a canvas core 2 having a C-shaped cross section in which a steel wire 1 is embedded, as shown in FIG.

Since escalator handrails are installed in department stores, supermarkets, airports, and other places where many people gather, the decorative rubber layer 3 is required to have the following characteristics.

(1) The surface has good gloss (2) The gloss does not deteriorate even after long-term use (3) The rubber does not crack or wear out even after long-term use Cosmetics of conventional escalator handrails As rubber,
Chlorosulfonated polyethylene rubber or chlorinated polyethylene rubber has been used, but these have not been fully satisfactory in terms of the above properties.

On the other hand, attempts have been made to coat the surface of the decorative rubber layer with silicone oil or polyurethane after molding to make it glossy, but in the case of silicone oil, the gloss disappears immediately after application, and in the case of polyurethane, there are several There was a problem in that after a few months, cracks appeared, which actually spoiled the aesthetic appearance.

In terms of formulation, it is known that when fillers such as clay, talc, and calcium carbonate are added to chlorosulfonated polyethylene rubber, the gloss increases, but even though these rubbers have initial gloss, they lack durability. There was a problem that the gloss was insufficient and the gloss was lost when used for a long period of time.

Another possible method is to improve the smoothness of the mold surface during molding to increase gloss, but the gloss obtained by such a method will be lost within a short period of time after use.

Therefore, to fundamentally solve the problem of surface gloss, it is necessary to improve and modify the rubber composition.

The present invention has been made to address these issues, and consists of 100 parts of chlorosulfonated polyethylene rubber, 30 to 70 parts of silane coupling-treated hard clay, 5 to 45 parts of magnesium carbonate, 3 to 30 parts of a softener, and polyethylene glycol. It is an object of the present invention to provide a chlorosulfonated polyethylene rubber composition comprising 2 to 10 parts and an effective amount of a copolymerizing or crosslinking agent.

As the chlorosulfonated polyethylene rubber used in the present invention, commercially available ones can be used, such as Hypalon #40 and Hypalon #40S (both trade names of EI DuPont, USA). .

It is also possible to blend chlorinated polyethylene into the above rubber if necessary, but in this case the ratio of chlorosulfonated polyethylene to chlorinated polyethylene is 100:
It is necessary to do this in the range of 0 to 70:30.

Examples of usable chlorinated polyethylene include ELATHLEN #301 and ELATHLEN #401 (both trade names of Showa Denko KK).

In the present invention, hard clay treated with a silane coupling agent and magnesium carbonate are used together as fillers.

As the silane coupling agent-treated hard clay, mercaptosilane- or aminosilane-treated hard clay is suitable.

The suitable amount of the silane coupling agent-treated hard clay is 30 to 70 parts per 100 parts of rubber.

If the amount is less than 30 parts per 100 parts of rubber, the imparting of surface gloss will be insufficient, and if it exceeds 70 parts, the processability of the rubber will deteriorate, so both are unsuitable.

As magnesium carbonate, ordinary commercially available products can be used, but those with a whiteness of 94 or more and an oil absorption of 130 to 180 are suitable.

The suitable amount of magnesium carbonate is in the range of 5 to 45 parts per 100 parts of rubber.

If it is less than 5 parts per 100 parts of rubber, it will not give sufficient surface gloss, and if it exceeds 45 parts, durability will be poor, so both are unsuitable.

Transparent or pale yellow softeners are suitable for use in the present invention, including phthalic acid softeners, sebacic acid softeners, azelaic acid softeners, epoxy softeners, and phosphoric acid softeners. Agents etc. can be used.

Among these, phthalic acid softeners and epoxy softeners are particularly suitable for the present invention.

A suitable blending amount of the softener is 3 to 30 parts per 100 parts of rubber.

If it is less than 3 parts per 100 parts of rubber, processability will be poor, and if it exceeds 30 parts, the rubber surface will become cloudy and the physical properties will deteriorate, so both are not preferred.

The polyethylene glycol used in the present invention includes:
Those with a molecular weight of 3,000 or more are suitable, and those with a molecular weight of around 10,000 are particularly suitable.

The appropriate amount of polyethylene glycol is in the range of 2 to 10 parts per 100 parts of rubber.

If the amount is less than 2 parts per 100 parts of rubber, the imparting of surface gloss will be insufficient, and if it exceeds 10 parts, the moldability will deteriorate, so both are not preferred.

Further, effective amounts of known vulcanizing or crosslinking agents such as sulfur-containing vulcanization accelerators, maleimide compounds, and organic peroxides are appropriately blended into the above composition.

In addition to these ingredients, vulcanization aids such as magnesia, Antige DAH (trade name of Kawaguchi Chemical Co., Ltd.),
Non-staining anti-aging agents such as NOKRATSUK NS#5 and NOKRATSUK NS#6 (both trade names of Ouchi Shinko Kagaku Co., Ltd.), titanium white, watching red, benzidine yellow, phthalocyanine green, phthalocyanine blue, and carbon black. , Bengara, and other pigments may be appropriately blended as required.

The rubber composition of the present invention is mixed in a conventional manner using a mixing roll or a Banbury mixer.

The rubber composition of the present invention thus obtained can be filled into a mold and vulcanized or crosslinked to give a molded product with excellent surface gloss.

Furthermore, the surface gloss after vulcanization or crosslinking molding is greatly affected by the roughness of the rubber in the undercoat molding, but the rubber composition of the present invention has extremely smooth undercoating during roll separation and extrusion.

Note that it is desirable that the surface of the mold used for vulcanization or crosslinking molding be chromium plated to give it a mirror finish.

Examples of the present invention will be described below.

Examples 1 to 3 The compositions shown in Table 1 were mixed using a Banbury mixer.
The rubber composition was kneaded at 50° C. for 6 minutes, and a test sheet with a thickness of 2 mm was produced using the rubber composition obtained under the conditions of a pressure of 100 kg/cm 2 , a temperature of 150° C., and a heating time of 20 minutes.

(The numbers represent parts by weight) The ingredients in the table are as shown below.

Magnesia: Manufactured by Kamishima Chemical Co., Ltd. Calcium carbonate: Manufactured by Shiraishi Calcium Co., Ltd. Nu Lock 321L: Manufactured by Huber Corporation, USA, hard clay treated with silane coupling Magnesium carbonate: Manufactured by Kamishima Chemical Co., Ltd. PEG 10000: Manufactured by Sanyo Chemical Co., Ltd. Polyethylene glycol (MW=10000) Accelerator 22: Kawaguchi Chemical Co., Ltd., vulcanization accelerator Accelerator TRA: Ouchi Shinko Kagaku Co., Ltd., vulcanization accelerator Accelerator D
M: Same as above HVA #2: E.I.DuPont, USA
Vulcanization accelerator DOP: manufactured by Daihachi Chemical Co., Ltd.
Dioctyl phthalate Adekasizer O-180A: manufactured by Adeka Argus Chemical Co., Ltd., plasticizer The properties of the obtained sheet were as shown in Table 2.

On the other hand, a handrail (length 10 m) having the structure shown in FIG. 1 was manufactured using the compositions of Example 1 and Comparative Example 2,
Changes in gloss over time were measured.

The measurement results are shown in Figure 2.

The gloss level is the value measured from vertically above the handrail using a gloss meter (visual observation shows approximately 60% gloss).
This gives the impression that it is shiny).

As is clear from the above examples, according to the present invention, it is possible to obtain a molded product that has excellent durability and surface gloss, and has mechanical properties similar to those of conventional products.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a handrail, and FIG. 2 is a graph showing changes over time in surface gloss of a handrail in which a decorative rubber layer is formed using the composition of the present invention. 1... Steel wire, 2... Canvas core, 3...
...Cosmetic rubber layer.

Claims (1)

[Claims] 1. 100 parts of chlorosulfonated polyethylene rubber, 30 to 70 parts of silane coupling treated hard clay, 5 to 45 parts of magnesium carbonate, 3 to 30 parts of a softener, 2 to 10 parts of polyethylene glycol, and an effective amount of A chlorosulfonated polyethylene rubber composition comprising a vulcanizing or crosslinking agent. 2. The chlorosulfonated rubber composition according to claim 1, wherein the softener comprises a phthalic acid softener, a sebacic acid softener, an epoxy softener, or a phosphoric acid softener.