JPS6289752A - Method for preventing staining of rubber surface - Google Patents

Abstract

PURPOSE:To prevent the staining of rubber surface for a long period, by compounding a rubber with a homopolymerized or copolymerized oligomer of an unsaturated ester having polyfluoroalkyl group. CONSTITUTION:The staining of a rubber surface can be prevented by compounding a rubber with preferably 0.01-10% (A) homopolymerized or copolymerized oligomer of an unsaturated ester containing 3-21C polyfluoroalkyl group, preferably a (meth)acrylate containing terminal perfluoroalkyl group or (B) a copolymerized oligomer composed of the unsaturated ester A and 10-90(wt)%, especially 40-80% other copolymerizable compound (e.g. ethylene, vinyl acetate, etc.) and having a number average molecular weight of 1,000-10,000, preferably 1,000-8,000 or their mixture (preferably composed mainly of the component B).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] Unreleased rJI relates to a method of preventing contamination of the rubber surface by mixing a specific fluorine-based oligomer into rubber.

[Prior art and its problems] Dirt on the surface of various rubber products often has a negative effect on product performance. For example, dirt on the surface of a rubber roll used for printing or copying hinders clear copying and causes contamination. In addition, in the case of rubber sealants for construction, etc., dirt on the rubber surface spoils the aesthetic appearance, and attempts have been made to make it difficult to get dirty. Conventionally, methods for preventing contamination of these rubber surfaces include applying a compound that has antifouling properties or forming an antifouling paint film, but the coating method has poor durability and is difficult to form a film. In the method,
It is not suitable for products that require a smooth rubber surface, and is not suitable for products where external force is applied to the rubber surface.
However, durability was a problem.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems 1 and 1. This invention relates to the production of rubber products with excellent antifouling properties and durability on the rubber surface by mixing fluorine-based oligomers with a certain price into rubber.

The fluorine-based oligobuty in the present invention is carbon, L number 3 to 2
Homopolymerized oligomer of unsaturated ester containing one polyfluoroalkyl group S (hereinafter referred to as oligomer A)
And/or oligomer A, which is a copolymerized oligomer of the unsaturated ester and another copolymerizable compound (hereinafter referred to as oligomer B), has a polyfluoroalkyl group in the monomer with the same number of carbon atoms, J. It includes not only the same oligomers but also copolymerized oligomers of different oligomers.

The unsaturated ester containing a polyfluoroalkyl group having 3 to 21 carbon atoms is not particularly limited, but, for example, the following 7 acrylate or methacrylate is preferable.

CFt (CFz)acH20cOc(CH3)=CH
2CF3 (CF2)6 (CH2)20COC(CH
3) =CH2CF, (CFz)60cOc-GH2
CF:l (CF2)lGH2CH20COCH=C
H2Oh(CF2)+5OIN(G:+HI)(OH;
・)70COCH=CH20Fco(CF2)I (O
Hshi)aOGOCI=C)bCFI (CF7)I
502N(CH3)(OH7)ノ0COCH(CH3)
=CH2GFt (CF2)/5O2N (C2[
5) (OH7)20COCH=GHnCF3(CFz)
tCONH(CH2)20GOCI-CH2CF3 (
CF2)8 (CH2)20GOCI-CH2CF3
(CFz)It CCH2)20COC(Cto)-C
H2O(CH2) + o CH20GOCH=CI?
CF2 CI CCF2 ) + o CH20COC
((H:+)-GH2 The compound that can be copolymerized with the unsaturated ester can be selected from a wide range of options, as long as it does not impede the effect of employing the present invention. For example, ethylene.

Vinyl acetate, 1! ! vinyl chloride, vinyl fluoride, vinylidene halide, styrene, α-methylstyrene, p-methylstyrene, acrylic acid and its furkynystyl, methacrylic acid and its alkyl ester, poly(oxyalkylene) acrylate, poly(oxyalkylene) methacrylate, Acrylic 7mide, methacrylamide, diacetone acrylamide, methylolated diacetone acrylamide, N-methylol acrylamide, vinyl alkyl ether, halogenated alkyl vinyl ether, vinyl alkyl ketone, f') diene, isoprene, chloroprene.

Glycidyl acrylate, benzyl methacrylate, benzyl acrylate, cyclohexyl acrylate, 2
- ethylhexyl methacrylate or acrylate, maleic anhydride, aziridinyl acrylate or methacrylate-1, methacrylate or acrylate with polysiloxane, N-vinylcarbazole, etc. = one type of compound that can be combined without a polyfluoroalkyl group Alternatively, it is possible to copolymerize two or more of them together as oligomer structural units. The ratio of these copolymerized components to the heel is usually 1 to 30 tons, preferably 40 to 80 weight percent.

In addition, in order to obtain oligomers A and B in the present invention, the raw material polymerizable compound is dissolved in a suitable organic solvent, and a polymerization initiation source ('am compound, diazo compound, or electrical circuit compound soluble in the organic solvent used) is dissolved in a suitable organic solvent. Due to the effects of radiation, etc.),
A solution polymerization method can usually be employed. Suitable solvents for solution polymerization are toluene, ethyl acetate, isopropyl alcohol, 1,1,2-)lichloro-11212-triple olethane, tetrachlorodifluoroethane, methylchloroform T. If the molecular weight of such oligomers is too large, the oligomers will become oriented on the rubber surface.
The number average molecular weight is about 1.000 to 10,000, preferably about 1.00, because the antifouling properties will be reduced, and if it is too small, the compatibility with rubber will be poor and the durability will be low.
It is recommended to select from the range of 0 to 8,000.H'EC? H40H, HSCH2C
0OH, H9Ca Hlr.

HSC1? H25, H9C2HaCsF+1. H9C2
The Jt4j oligomer, which may be used as an ilj chain transfer agent of HnCOOC2HaCsF++S, may have a random, block, or graft form as appropriate.

The method of mixing the fluorine-based oligomer into the rubber in the present invention is not particularly limited, and various methods may be adopted depending on the type and form of the rubber. For example, dispersing the fluorine-based oligomer in water or using an organic solvent. After immersing the unvulcanized rubber powder in this solution, the water and solvent are evaporated to obtain a powder to which the fluorine-based oligomer is attached, followed by a vulcanizing agent and a vulcanization accelerator.

There are two methods: kneading together with other compounds such as antifouling agents, or kneading solid fluorine-based oligomers with unvulcanized rubber and other compounds. For kneading, a Banbury mixer, a roll, or an extruder T may be used, and a method of adding a fluorine-based oligomer to a rubber solution and stirring and mixing may also be adopted. Alternatively, the fluorine-based oligomer can be previously dispersed in other formulations using a ball mill or a homomixer.

When dispersing the fluorine-based oligomer in water, various surfactants such as nonionic, anionic, cationic, or amphoteric surfactants can be used as dispersants. As an organic solvent,
Alcohols such as ethyl alcohol and isopropyl alcohol, acetone, methyl ethyl ketones, esters such as methyl acetate, ethyl acetate and isoamyl acetate, ethers such as diethyl ether and dioxane, methyl chloroform, trichloroethylene, tetrachloroethylene, tetrachlorodifluoroethane, 1.
1.2-) One or a mixture of two or more halogenated hydrocarbons such as dichlorotrifluoroethane and metaxylene hexafluoride may be used. The amount of fluorine-based oligomer in water or solvent is usually o. i~50 ball amount%, preferably lN10@%.

Incorporation of fluorine-based oligomers into rubber, IIS,
0, 01-to tun? % is preferable, and even a small amount of 0.1 to 2.0% is sufficient to prevent contamination. Oligomer A
and B can be incorporated into the rubber either alone or as a mixture, but when used in combination, it is preferable to use oligomer B as the main component since the stain prevention effect is long lasting (durable). Usually, unvulcanized rubber containing fluorine-based oligomers and other compounds is vulcanized and molded into various rubber products. It has higher antifouling properties than sulfur. This is considered to make it easier for the oligomer to migrate to the rubber surface.

By mixing the fluorine-based oligomer in the present invention into rubber, contamination of the rubber surface can be prevented, but the type of rubber is not limited at all, and natural rubber,
Styrene butadiene rubber, butadiene rubber, acrylonitrile butadiene rubber, nitrile rubber, chloroprene rubber, acrylic rubber t%. Ethylene propylene rubber.

Examples include polyurethane rubber, butyl rubber, epichlorohydrin rubber, polyurethane rubber, fluororubber, silicone rubber, and blends thereof. These rubbers may also contain fibrous reinforcing materials. Moreover, according to the present invention, 1! ) Highly antifouling rubber can be used for paper patterns, printing office machines, dyeing, textiles, and for electronic copying machines, such as gols, rolls, joints, around sashes, and for joining curtain walls. Architectural sealing materials are suitable for applications such as, but not limited to, transmission belts, conveyor belts, tires, rubber hoses, rubber plates, rubber footwear, anti-vibration rubber, fenders, rubber linings, waterproofing, etc. It can be applied to various rubber products such as coatings, backings, gaskets, foam rubber, and f-bags.

[Function] In the present invention, when a fluorine-based oligomer is mixed into rubber, the mechanism by which high antifouling properties are imparted to the rubber surface is not necessarily clear. Because of the low surface energy of the polyfluoroalkyl group, the oligomer migrates to the rubber surface after being mixed into the rubber, and the polyfluoroalkyl group is oriented on the rubber surface, making it an antifouling agent. It is thought that gender can be attached. In addition, the reason for the high durability is the remarkable entanglement between the rubber molecules and oligomer molecules, or the anchoring effect between the compatible groups in the oligomer molecules and the rubber molecules, which prevents the oligomers from detaching from the rubber surface. This is thought to be because it becomes difficult. Such explanations are helpful in understanding the present invention, and do not limit the present invention in any way.

[Example] Production of oligomer A specified monomer and ethyl butyrate were placed in a Mitsuro flask equipped with a reflux device. Furthermore, mercaptan was added as a molecular weight regulator to the target molecular weight, and azobisisobutyrinitrile was added as an initiator.
After 0 hours of reaction, the solvent was removed by vacuum drying to obtain various fluorine-based oligomers with a solid content of 1,002.

[Evaluation of antifouling property] Rubber kneaded with fluorine-based oligomer obtained by the method described above, a vulcanizing agent, a vulcanization accelerator, and a quaternization inhibitor was press-colored at 120°C, and a flat plate with a diameter of about 14 cm was formed. A shaped rubber molded body was obtained. Using this rubber molded article, the rug test method described in JIS L-1021 was carried out, and the contamination test was conducted 10,000 times and 20,000 times, and then the degree of contamination was observed under 11 visual inspection.

The results are shown in Table 1 together with comparative examples containing compounds other than oligomers and no compound.

7.Resistance: 7.0% and 10.0% are good, so dirt hardly sticks to them.
・・・・・・7 Rire's old wear area 90-40% defective...
...The entire surface is covered with dirt [Effect of the invention] By mixing the fluorine-based oligomer of the present invention into rubber, it is possible to prevent contamination on the rubber surface, and it has excellent durability, and it also prevents adhered dirt. can also be removed relatively easily.

For example, when removing printing ink from a printing rubber roller L, conventionally it is necessary to use a solvent that causes the rubber to swell, and there is a risk that the diameter of the roller may change due to swelling, reducing printing accuracy. However, rubber rollers containing fluorine-based oligomers can remove dried and fixed ink residue without using solvents that cause swelling.

In addition, when unvulcanized rubber after extrusion or rolling is stacked and stored in a winding rack, the rubber becomes viscous to each other and workability deteriorates, but rubber containing fluorine-based oligobo
Non-adhesive properties can be added to the rubber surface, making it easy to stick to.
This improves work efficiency.

-r-Osine City Official Book Date of 1986

Claims (1)

[Claims] 1. A homopolymerized or copolymerized oligomer of an unsaturated ester containing a polyfluoroalkyl group having 3 to 21 carbon atoms, and/or a combination of the unsaturated ester and another copolymerizable compound. A method for preventing contamination of a rubber surface, which comprises mixing a copolymerized oligomer into rubber. 2. The method for preventing contamination according to claim 1, wherein the unsaturated ester containing a polyfluoroalkyl group is an acrylate or methacrylate containing a terminal perfluoroalkyl group.