JPH05320212A - Internally cross-linked fine particle and rubber composition containing the same - Google Patents

Abstract

PURPOSE:To provide an organic filler having a low specific gravity and a suffi cient ability to reinforce a rubber. CONSTITUTION:The fine particles are prepared by finely dispersing at least one free radical-reactive monofunctional monomer and at least one free radical- reactive polyfunctional monomer in water and polymerizing the monomers. The rubber composition is prepared by compounding these particles with a rubber component. An example of the monofunctional monomer is styrene, and an example of the polyfunctional monomer is divinylbenzene.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to internally crosslinked fine particles and a rubber composition containing the fine particles.

[0002]

2. Description of the Related Art Fillers are one type of rubber compounding agents. Inorganic fillers have a large specific gravity and are essentially incompatible with rubber matrix. Surface treatment and the like have been carried out in order to improve the compatibility, but it has not been easy to obtain a material that chemically bonds to the rubber matrix.
In addition, organic fillers having a low specific gravity are commercially available, but none have sufficient reinforcing properties.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide an organic filler having a low specific gravity and a sufficient reinforcing property for rubber.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides an internal structure obtained by finely dispersing at least one radical-reactive monofunctional monomer and at least one radical-reactive polyfunctional monomer in water, and then polymerizing them. The present invention relates to crosslinked fine particles and a rubber composition containing the same as a rubber component.

In the present invention, examples of the radical-reactive monofunctional monomer include aromatic vinyl compounds such as styrene, aliphatic vinyl compounds such as vinyl chloride and vinyl acetate,
Examples thereof include vinyl or allyl ethers such as methyl allyl ether and methyl vinyl ether, and (meth) acrylic acid esters.

Examples of the radical-reactive polyfunctional monomer include divinylbenzene, allyl (meth) acrylate, ethylidene norbornene, dicyclopentadiene, polyvalent acrylic acid esters, diallyl phthalate,
Examples include triallyl isocyanurate.

The use ratio of the monofunctional monomer and the polyfunctional monomer is not particularly limited, but it is necessary that a certain amount of double bonds remain after the polymerization, and the molar ratio of the monofunctional monomer to the polyfunctional monomer is preferably. The ratio is 5: 1 to 1: 5, particularly preferably 3: 1 to 1: 3.

The production method may be an ordinary radical polymerization method, and in particular, an emulsion polymerization method or a suspension polymerization method is preferable in order to keep the polymer particles in fine particles. In particular, emulsion polymerization is preferable in order to obtain fine particles having a stable particle size distribution. In the case of suspension polymerization, an oil-soluble initiator is usually used, and the polymerization temperature is preferably 0 to 100 ° C. and the polymerization time is preferably 0.5 to 24 hours.

In the case of emulsion polymerization, a conventional water-soluble initiator can be used as the radical polymerization initiator. The polymerization temperature is usually about 0 to 100 ° C., and the polymerization time is usually about 0.5 to 24 hours.

The fine particles obtained as described above are strongly internally crosslinked, and the double bond remaining on the surface easily obtains the reinforcing property, and is useful as an organic filler.

Next, the present invention also relates to a rubber composition containing the above internally crosslinked fine particles (hereinafter, also referred to as an organic filler) in a rubber component. An organic peroxide vulcanizable or sulfur vulcanizable rubber is used as the rubber component. For example, butadiene rubber such as polybutadiene rubber, SBR, NBR (including hydride), silicone rubber, olefin rubber such as EPDM, Examples thereof include acrylic rubber having a double bond in the side chain, iodine and / or bromine-containing fluorine rubber, and the like.

The compounding ratio of the rubber component and the organic filler varies depending on the system, but when the rubber component is fluorocarbon rubber, the organic component is added to 100 parts of fluorocarbon rubber (parts by weight, the same applies hereinafter). About 5 to 40 parts are preferable, and 5 to 20 parts are particularly preferable. If it is less than 5 parts, the effect of addition is small,
On the other hand, if it exceeds 40 parts, the strength will decrease.

In the present invention, the above-mentioned organic filler is finely dispersed in the above-mentioned organic peroxide vulcanizable synthetic rubber, and an ordinary compounding agent is added to the rubber for vulcanization. In order to secure the fine dispersion, it is preferable that the emulsion of the organic filler produced by radical polymerization as described above and the dispersion of rubber are mixed and co-deposited.
As the compounding agent, usual compounds can be used and are not particularly limited, and examples thereof include processing aids, plasticizers, colorants, vulcanization aids such as triallyl isocyanurate, and organic peroxide vulcanizing agents. Be done. It may contain an inorganic filler such as carbon black, silica, clay, diatomaceous earth, or calcium carbonate. For vulcanization, the composition is prepared by using an internal mixer such as an open roll or a kneader, press vulcanized at a temperature of 100 to 200 ° C. for 1 to 120 minutes, and optionally oven vulcanized. .. The conditions for oven vulcanization may be the same as usual, but for example, a range of 10 minutes to 48 hours at 150 to 300 ° C is adopted.

[0014]

Examples 1 to 7 4 parts of a surfactant (sodium lauryl sulfate) was added to 100 parts of the monomer mixture shown in Table 1, and the mixture was passed through a high pressure emulsifying machine to emulsify it, and then a water-soluble polymerization initiator (t -Butyl hydroperoxide) was used for radical polymerization at 70 ° C. for 8 hours under a nitrogen stream. The particle size of the obtained fine particles and the concentration of double bonds on the particle surface measured by the mercury acetate method are also shown in Table 1. 5FMA is _{CH 2 = C (CH 3)} COOCH
₂ CF ₂ CF ₃ is shown.

[0015]

[Table 1]

Examples 8 to 16 and Comparative Example 1 Daier G-902 emulsion dispersions were added to the organic filler dispersions obtained in Examples 1 to 7 in the proportions shown in Table 2, and co-dispersed with magnesium chloride. Was allowed to settle. After washing and drying, 4 parts of TAIC and 2.5 parts of perhexaline were added to 100 parts of this mixture.
After blending 1.5 parts of B using an open roll, 160 ° C
And press vulcanized for 30 minutes. The physical properties of the obtained vulcanizate were measured by the following methods, and the results are shown in Table 2. In addition, DAI-EL G-902 is vinylidene fluoride (2F), hexafluoropropene (6F) and tetrafluoroethylene (4F) ternary copolymer fluorine rubber, TAIC is triallyl isocyanurate, and perhexa 2.5B is NOF Corporation. Made of peroxide. 100% Module: JIS K6301 Tensile Strength: JIS K6301 Elongation: JIS K6301 Hardness: JIS K6301

[0017]

[Table 2]

[0018]

When the organic filler of the present invention is blended with an organic peroxide vulcanized or sulfur vulcanized rubber, a vulcanized product having good physical properties can be obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location C08L 57:00) (72) Inventor Yoshihiro Shirai 1-1 Nishiichitsuya, Settsu-shi, Osaka Daikin Industrial Co., Ltd. Company Yodogawa Works (72) Inventor Etsushi Minamino 1-1, Nishiichitsuya, Settsu City, Osaka Prefecture Daikin Industrial Co., Ltd. (72) Masayasu Tomoda 1-1, Nishiichitsuya, Settsu City, Osaka Yodogawa Corporation Inside the factory

Claims (2)

[Claims] 1. Internally crosslinked fine particles obtained by finely dispersing at least one radical-reactive monofunctional monomer and at least one radical-reactive polyfunctional monomer in water, and then polymerizing them. 2. A rubber component containing internally crosslinked fine particles obtained by finely dispersing at least one radical-reactive monofunctional monomer and at least one radical-reactive polyfunctional monomer in water and then polymerizing them. A rubber composition blended with.