JPH0747301B2 - Metal-Fluoroelastomer-Composite Material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to metal-fluoroelastomer composites.

More specifically, the present invention relates to a metal-fluoroelastomer composite material in which a metal portion and a vulcanized fluoroelastomer portion are adhered to each other with high adhesive strength.

Fluoropolymers, especially vinylidene fluoride, such as ionic,
Fluoroelastomers based on those vulcanized by amine or peroxide type processes are known in some industrial fields because of their high thermal stability and also their chemical resistance at high temperatures. It is a compound.

Due to such thermal stability and chemical resistance, the compounds are used in particular continuously under severe temperature conditions, especially in contact applications with organic or inorganic fluids characterized by high chemical attack.

For example, one of the most important applications of fluoroelastomers is in the manufacture of static-dynamic dual-purpose gaskets.

A particularly important area from this point of view is the on-axis sealing performed by shaft seals.

In this case, it is absolutely possible that a perfect adhesion is achieved between the fluoroelastomer that constitutes the sealing member and the metal insert, and that the adhesion can remain unchanged even at high temperatures (100-250 ° C). It is essential.

Diamine derivatives, such as carbamates, have been used in known methods to vulcanize fluoroelastomers in the past excessively and now to a lesser extent.

However, such accelerator-vulcanizing agents, even though they allow sufficient bond strength to be achieved, have the disadvantage that elastomeric processing is not very reliable due to the occurrence of the scorch phenomenon. .

By using other vulcanization systems based on accelerators such as quaternary phosphonium or aminophosphonium salts where the anion is predominantly chloride, bromide or tetrafluoroborate, for example bisphenols and The scorch phenomenon is eliminated, but the adhesive strength deteriorates.

As a result, products such as the already mentioned shaft seals, which consist of metal parts with fluoroelastomer applied to the surface, have a short service life, so frequent replacement work must be performed, and undesired mounting of the product is also accompanied. There must be a time to stop working on the machinery.

However, surprisingly, the fluoroelastomer moiety used was such that 0.001 of bromine attached to a carbon atom in the polymer chain.
A metal moiety, when composed of a copolymer of vinylidene fluoride containing 1 to 2% by weight and hexafluoropropene and optionally another comonomer selected from fluoroolefin and / or perfluorovinyl ether; It has been discovered that it is possible to obtain a metal-fluoroelastomer composite material in which a vulcanized fluoroelastomer portion is adhered to each other with high adhesive strength. Thus, this composite material is the subject of the present invention. According to a preferred embodiment, bromine is included in the range 0.01 to 1% by weight.

Fluoroelastomers used in accordance with the invention are, for example, Kirk Othmer Encyclopaed
ia of Chemical Technology, Volume 8, pp. 504 et seq. (19
Obtained by known techniques such as those described in 79). As a chain transfer agent for the copolymerization reaction, the general formula C _p X _q Br _m (where X can be a either fluorine or chlorine, p is an integer of 1 to 4 range, m is the 1~2p + 2 range Is an integer, and q has a value of 2p + 2-m), bromine is introduced into the copolymer.

The chain transfer agent is added to the reacting monomer in an amount ranging from 0.01 to 0.3 mol%. The preferred transfer agent is CF ₂ Br ₂ .

If the above compounds are used for the copolymerization of vinylidene fluoride with hexafluoropropene and optionally with other fluoroolefins and / or perfluorovinyl ethers, it is possible to control the molecular weight in the same way as with all chain transfer agents, in addition to the metal It is possible to achieve a high adhesion strength of the fluoropolymer to.

The fluoroelastomers used according to the invention are vinylidene fluoride 35-80 mol%, hexafluoropropene 15-
35 mol% and 0 to 30 mol% of another comonomer selected from fluoroolefins and / or perfluorovinyl ethers.

The fluoroolefin can be selected from tetrafluoroethylene, chlorotrifluoroethylene, vinyl fluoride and the like, and the perfluorovinyl ether can be selected from perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, perfluoropropyl vinyl ether and the like.

Particularly preferred is a copolymer containing 75-80 mol% vinylidene fluoride and 20-25 mol% hexafluoropropene or 35-80 mol% vinylidene fluoride, 15-35 mol% hexafluoropropene and 30% tetrafluoroethylene. Mol%
It is a terpolymer that includes: Fluoroelastomers used in accordance with the present invention include known curing agents such as dihydroxy compounds described in U.S. Pat.
er Chemistry and Technology, Vol. 51, p. 940 (197
It can be vulcanized by using a peroxy crosslinking agent described in 8) and a peroxy compound such as an organic peroxide.

As accelerators in the vulcanization process with dihydroxy compounds, the quaternary ammonium, phosphonium or aminophosphonium compounds disclosed in British Patent 1,356,344, US Pat. No. 3,876,654 or British Patent 2,010,285, respectively, can be used.

The operating conditions for preparing and vulcanizing the compound are substantially in the range normally employed for the fluoroelastomers described by Kirk Osmer, cited above.

Any metal or alloy may be used to produce the composite material of the present invention, but in particular iron, copper, zinc, aluminum and the like, as well as alloys of these metals such as steel, special steel, cast iron,
Bronze, brass, etc. can be used.

To produce the composite material of the present invention, it suffices to treat the metal parts with a degreasing agent and sandblasting and then apply an adhesive to adhere the two parts to each other.

80 x 25 x 2 mm, taking into consideration ASTM standard D816 to evaluate the adhesion strength between vulcanized elastomer composition and metal
Sandwich shaped samples were prepared consisting of two dimensional carbon steel UNIFe-37A plates sandwiching a fluoroelastomer layer. The plate is Algofrene 113
(1,1,2-Trichlorotrifluoroethane) was degreased in a steam bath, the adhered surface was sandblasted with corundum (particle size 0.01 mm), and then degreased again. Then, the adhesive was sprayed on the surface to be attached.

Chemosil 511 (Henkel trade name) was used as the adhesive.

Adhesion between the adhesive treated plate and the elastomer is achieved in a press vulcanization process. The overlapping area is about 625 mm ²
(Rubber thickness = 3.8 mm).

Molding condition: P = 6 to 7 MPa T = 170 ± 2 ° C.

To further illustrate the present invention and practically embody it, non-limiting illustrative examples are set forth below.

Example 79% vinylidene fluoride and 21 perfluoropropene
Elastomer (A) having a composition of mol% and elastomer (B) having a composition of 79 mol% of vinylidene fluoride, 21 mol% of perfluoropropene and 0.15% by weight of bromine
These two fluoroelastomers (both have a Mooney viscosity ML (1 + 4) of 60 at 100 ° C of 60) are mixed in a cylinder mixer, and rubber 100 parts by weight bisphenol AF 1.6 parts by weight accelerator 0.45 parts by weight MgO 3 parts by weight Ca ( OH) was ₂ made of 6 parts by weight MT wander 30 parts identical vulcanization formulation.

As a formula, Was used.

For each rubber, under 6 MPa to prove its mechanical properties 17
A series of tests were carried out after press vulcanization at 5 ° C. for 10 minutes.

The results are shown in the table below. Table 1 (A) (B) 100% module, MPa 5.7 5.8 Tensile strength, MPa 15 15.1 Elongation at break,% 185 194 Hardness (Shore A) 73 73 80 × 25 × 2mm carbon steel UNI Fe-37A Each unvulcanized rubber sample having a 3.8 mm thickness and an area of 625 mm ² was placed between two plates and degreased in an Algofrene 113 (1,1,2-trichlorotrifluoroethane) steam bath to give a particle size of 0.01 mm. Sandblasted with corundum.

Chemosyl 511 on one side of these two plates
Was applied in a thin layer.

Adhesion between the adhesive treated plate and the elastomer is achieved by a press vulcanization process at 170 ° C. under 6 MPa.

Ten minutes later, at the end of the vulcanization process, a test was conducted to verify the adhesive strength of the two samples, and in the case of fluoroelastomer (A), a peel stress (shear stress) of 29 MPa was applied to the sample. After that, peeling of the metal plate occurred, whereas the fluoroelastomer (B) was torn without peeling when the stress reached 8 MPa.

Claims (8)

[Claims] 1. A metal-fluoroelastomer composite material comprising a metal part and a part made of a vulcanized fluoroelastomer adhered to each other with high adhesion strength, wherein the fluoroelastomer part comprises 35 to 80 mol% of vinylidene fluoride. ,
Hexafluoropropene 15-35 mol%, another comonomer selected from fluoroolefin and / or perfluorovinyl ether 0-30 mol% and bromine 0.001-
Composite material composed of 2% by weight. 2. The composite material according to claim 1, wherein the fluoroolefin is selected from tetrafluoroethylene, chlorotrifluoroethylene and vinyl fluoride. 3. A composite material according to claim 1, characterized in that the perfluorovinyl ether is selected from perfluoromethyl vinyl ether, perfluoroethyl vinyl ether and perfluoropropyl vinyl ether. 4. The fluoroelastomer portion comprises 35 to 80 mol% of vinylidene fluoride and 15 to 35 mol% of perfluoropropene.
The composite material according to claim 1, which is constituted by a terpolymer containing at least 30 mol% of tetrafluoroethylene. 5. A fluoroelastomer moiety comprising a copolymer comprising 75-80 mol% vinylidene fluoride and 20-25 mol% perfluoropropene. The described composite material. 6. The composite material according to claim 1, wherein the bromine content is in the range of 0.01 to 1% by weight. 7. The copolymer has the general formula C _p X _q Br _m (where X can be either fluorine or chlorine, p
Is an integer in the range of 1 to 4, m is an integer in the range of 1 to 2p + 2, and q has a value of 2p + 2-m), the bromine is introduced by a chain transfer agent of 7. The composite material according to any one of items 1 to 6. 8. Composite material according to claim 7, characterized in that the chain transfer agent is CF ₂ Br ₂ .