JPS61181869A - Magnesium oxide having improved adhesion to metallic surface - Google Patents

Abstract

PURPOSE:To obtain magnetsium oxide having improved adhesion to a metallic surface, by blending a mineral oil, a plasticizer or an inorg. or org. extender with magnesium oxide powder. CONSTITUTION:5-500pts.wt. at least one member selected from among mineral oil, plasticizer, inorg. extender and org. extender is blended with 100pts.wt. magnesium oxide powder. Examples of the mineral oil are paraffinic oil, naphthenic oil and aromatic oil. Examples of the plasticizers are dioctyl phthalate and tricresyl phosphate. Examples of the inorg. extender are talc and calcium carbonate. Examples of the org. extender are pigment, org. processing aid and stabilizer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to magnesium oxide with improved adhesion to metal surfaces.

Magnesium oxide can be used as a filler, crosslinking agent, crosslinking aid, activator, acid acceptor, etc. in natural rubber, styrene butadiene rubber, nitrile rubber, chloroprene rubber, chlorinated ethylene propylene rubber, chlorosulfonated polyethylene, chlorinated It is well known that it is used mixed with various rubbers and resins such as polyethylene, polyethylene, polyvinyl chloride, and polyethylene vinyl acetate.

Magnesium oxide is often used in the form of powder with a particle size of 20 μm or less in order to improve its dispersibility in rubbers and resins and to fully exhibit its functions and effects.

Rolls, kneaders, banburys, etc. are used to mix powdered magnesium oxide with rubber or resin, and sometimes a continuous mixer is used. A major problem existed in that the metal particles adhered to the metal surfaces of the mixing section of the mixer. For example, magnesium oxide adheres to the surfaces of rolls, the inner walls of mixing chambers, and the surfaces of screws or rotors in closed mixers such as kneaders and Banburys. This adhesion occurs under high shear forces during mixing and forms a strong magnesium oxide layer on the metal surface. This adhesion layer of magnesium oxide is not only strong in itself, but also has a very strong adhesion to the metal surface, so it cannot be easily removed, resulting in an error in the mixing amount, which can cause problems in rubber products and resin products. A problem arises in that quality is greatly impaired. Furthermore, removing the adhesion layer of magnesium oxide once formed on the metal surface requires a lot of time and effort, such as polishing the metal surface. Therefore, preventing the adhesion of powdered magnesium oxide to metals has been a major challenge.

In view of this, the present inventors conducted studies to improve the adhesion of powdered magnesium oxide to metal surfaces, and found that by blending and mixing a specific amount of a specific compounding agent with powdered magnesium oxide The inventors have discovered that the above object can be achieved, leading to the present invention.

That is, the present invention provides a metal part characterized in that 5 to 500 parts of at least one selected from mineral oil, plasticizer, inorganic filler, and organic filler are blended per 100 parts by weight of powdered magnesium oxide. The present invention provides magnesium oxide with improved adhesion to surfaces.

Here, the mineral oil used in the present invention includes paraffin oil, naphthenic oil, aroma oil, spindle oil, etc., and the plasticizer includes dioctyl phthalate,
Phthalic acid esters such as dibutyl phthalate, adipic acid esters such as dioctyl adipate, phosphoric acid esters such as tricresyl phosphate and trioctyl phosphate, liquid paraffin, chlorinated paraffin oil, vegetable oil such as linseed oil, animal oil, and even liquid Inorganic extenders include talc, clay, calcium carbonate, silica, etc.; organic extenders include various carbon blacks, pigments, organic processing aids, and stabilizers. These are exemplified respectively, and these may be used alone or in combination of two or more.

Selection of mineral oils, plasticizers, inorganic and organic fillers,
The types, combinations, and amounts used are determined by taking into account the purpose of use of powdered magnesium oxide, its use, price, ease of handling, and compatibility with rubber and resin to be mixed. 5 to 500 parts by weight, preferably 20 parts by weight per ioozm part of powdered magnesium oxide.
~aooi parts, generally an inorganic filler,
When organic fillers are used, the amount used is larger than when mineral oils and plasticizers are used.

In addition, regarding the powdered magnesium oxide that is the object of the present invention, the term "powdered" is used in a general sense, and there is no particular restriction on the upper limit of the particle size, but the particle size is 80μ or less. The effects of the present invention are remarkable when the object is powdered magnesium oxide.

The method of blending powdered magnesium oxide with at least one selected from mineral oil, plasticizer, inorganic filler, and organic filler includes mechanical mixing using a blender, mixer, laika, polmill, etc., or mixing with toluene, etc. This is carried out by a method of mixing in the presence of a suitable solvent and then removing the solvent.

The powdered magnesium oxide mixture that is mixed by stirring takes the form of powder or paste depending on the type of mixture, etc., but it is mixed with rubber or resin in that form and is used to produce various rubber products. Used for manufacturing resin products.

The present invention will be explained below with reference to Examples.

However, "Example Middle" indicates parts by weight.

Example 1 100 parts of powdered magnesium oxide and 200 parts of FEF carbon black were mixed using a Henschel mixer.

100 parts of chloroprene rubber kneaded in advance using a Banbury mixer, 60 parts of FEF carbon black,
50 parts of aromatic process oil and 0.0 parts of stearic acid.
After winding the mixed wire consisting of 5 parts on the back roll side of a 10-inch roll at 40°C, 12 parts of the powdered magnesium oxide mixture mixed with the above FEF carbon black was added and mixed, but the mixture did not reach the roll surface. No adhesion of magnesium oxide was observed at all, and the addition work was completed in 30 seconds.

For comparison, the same procedure as above was performed except that 4 parts of powdered magnesium oxide was used as it was instead of using the powdered magnesium oxide mixture. As a result, magnesium oxide was deposited in a layer on the front roll surface. There was no change in the adhesion state even after 5 minutes or more passed, and it was not possible to add the entire tg of magnesium oxide to the chloroprene kneaded product. The magnesium oxide layer adhering to the roll surface was removed by using a metal force of 1 ton, but the work required about 2 minutes, and the amount of magnesium oxide adhering to the roll surface obtained by removal was 0.00% as a result of weight measurement. It was found that the amount was as much as 2 parts by weight.

Example 2 100 parts of powdered magnesium oxide and 200 parts of diisodecyl phthalate were mixed using a ball mill to obtain a paste-like magnesium oxide mixture.

A Banbury kneaded product consisting of 100 parts of chlorinated ethylene propylene rubber with a chlorine content of 20% by weight, 60 parts of FEF carbon black, 30 parts of diisodecyl phthalate, and 1 part of stearic acid was wound around the back roll side of a 10-inch roll at 40°C. Thereafter, 80 parts of the above paste-like magnesium oxide mixture was added and mixed, but no adhesion of magnesium oxide to the roll surface was observed.

For comparison, 10 parts of powdered magnesium oxide was directly added to the same chlorinated ethylene propylene rubber Banbury kneaded product as above (however, the amount of diisodecyl phthalate was 50 parts) and mixed in the same manner, but after 5 minutes. Even after this, the adhesion layer of magnesium oxide on the front roll surface did not disappear, and complete blending could not be achieved.

Example 3 100 parts of chlorinated polyethylene with a chlorine content of 40%, FE
40 parts of F carbon black, 5 parts of diisodecyl phthalate
After putting the Banbury kneaded product (naturally cooled to room temperature) consisting of 0 part of stearic acid and 1 part of stearic acid into Banbury at 60°C,
Immediately, 30 parts of the same FEF carbon black blended magnesium oxide mixture as described in Example 1 was added, and 80 parts of the same mixture of FEF carbon black was added.
After mixing for seconds, it was taken out.

No magnesium oxide was observed on any metal surfaces such as the Banbury mixing chamber inner wall, floating weights, or rotor.

For comparison, the same chlorinated polyethylene Banbury kneaded product as above (however, the blending amount of FEF carbon bran was 60
10 parts of powdered magnesium oxide was directly added to (10 parts) and mixed in the same manner, but adhesion of magnesium oxide to the inner wall of the floating weight was observed.

When adding magnesium oxide in Banbury, it generates heat over time and causes a scorch problem, so increasing the mixing time is problematic and impractical, but the magnesium oxide mixture according to the present invention is easy to mix. ,
Very useful in practice.

Claims (1)

[Claims] Adhesion to metal surfaces is characterized by containing 5 to 500 parts by weight of at least one selected from mineral oil, plasticizer, inorganic filler, and organic filler per 100 parts by weight of powdered magnesium oxide. Improved Magnesium Oxide