Patent Application
20120129979
The present invention relates on epoxy-rubber composition that can be used as matrix of all the kinds of composite materials such as coatings, reinforced and laminated plastics, sealants, adhesives, polymer concretes etc.
The use of a variety of toughening agents to modify epoxy resins improves the fracture toughness of epoxy systems. Many factors affect the thermal and mechanical properties of such epoxy systems. Epoxy resins are defined as any molecules containing one or more 1,2 epoxy groups, mainly terminated, that can be converted to a thermoset form or a three-dimensional network structure. Depending on the chemical structure of the curing agents and on curing conditions, the properties of cured epoxy resins are versatile, including excellent chemical and heat resistance, high adhesive strength, low shrinkage, good impact resistance, high strength and hardness, and high electrical insulation. But cured epoxy systems have a main drawback: their considerable brittleness, which shows poor fracture toughness, poor resistance to crack propagation and low impact strength. This inherent brittleness has limited their application in fields required high impact and fracture strengths, such as reinforced plastics, matrix for composites and coatings.
Rubber-modified epoxy resins exhibit increased fracture toughness, but also show the deterioration of other important properties compared to the unmodified resin. As was shown in the article [I. Ryb'ev, N. Blank, O. Figovsky. Polymer conglomerates based on epoxy-rubber compositions. Building Materials, 1978, No. 6, pp. 26-27—in Russia] the properties of rubber-modified epoxy resins using as a matrix for anticorrosive composite materials depend not only from types of epoxy resins, liquid rubber and curing agent but also from heterogenic structures of these systems, that could be characterized by an integral indicator—a specific surface of phases division.
Depend of application conditions many patents described different epoxy-rubber composition. Epoxy resin adhesive composition is described in U.S. Pat. No. 4,749,738; it contains an epoxy compound and a reaction product of an aliphatic polyamine with a diene type liquid rubber having a terminal carboxyl group, which is valuable for bonding of FRP. Another composition is disclosed in U.S. Pat. No. 5,075,379 a curing agent for epoxy resins a rubber/diamine blend, more particularly, diaminoisopropylbenzene (DAIPB) modified with an amine terminated butadiene liquid rubber (ATBN). Epoxy adhesive composition is disclosed in Japan patent No. 8218051. This adhesive composition essentially comprises an epoxy resin, modified acrylonitrile-butadiene liquid rubber with terminated carboxyl groups and polyamic acid curing agent. Epoxy resin composition flexibilized with liquid and hydroxyl rubber is disclosed in Chinese patent No. 1277225. This composition is prepared with bisphenol A epoxy resin, organic tinphosphate, liquid rubber having terminated hydroxyl groups.
As a typical example of epoxy-rubber curable crack-resistant composition it is possible to see the composition according U.S. Pat. No. 3,926,903 filled on Sep. 30, 1974 comprises, in weight percent referring to the total weight of components (a) and (b): (a) 92-94% of a bicyclopentadiene ether epoxy resin, (b) 6-8% of a reactive elastomer selected from the group consisting of a functionally terminated butadiene homopolymer, a functionally terminated butadiene-acrylonitrile copolymer and a functionally terminated butadiene-styrene copolymer and c) an aromatic polyamine curing agent in an amount sufficient to provide 0.5-2.0 amino hydrogen atoms of the amine for each epoxy group.
This invention provides epoxy/rubber composition with improved mechanical characteristics.
To realize this invention, an embodiment is an epoxy resin composition for a cured material, comprising:
an epoxy resin comprising an epoxy compound X, the epoxy compound X has epoxy equivalent weight (EEW) from 150 up to 200 and viscosity from 2,000 up to 10,000 cps (25 C),
a curing agent,
a liquid rubber that is liquid at room temperature and comprises at least 1.5 reactive terminated group,
a fluorine contained organic matter, selected from a group, including
where: n=1-20;
X=—COOH, —CONH2, —CON(C6H5)2, —CH2OH.
b) CF3(CF2)nCOOH, where: n=7-9.
where: n=3-20.
The composition according this invention comprises 0.1-1.0 parts of the above described fluorine contained organic matter to 100 parts of an epoxy compound by a ratio epoxy compound/liquid rubber 100/1.5-28. The composition according this invention can comprise additionally different additives and fillers according to application needs.
The composition according the present invention comprises as an epoxy resin low molecular weight oligomers with at least two terminated epoxy groups such as glycidic ethers of bis-phenol A, bis-phenol F, other bis-phenols, alkylresorcinols, novolac low molecular resins, acrylic low molecular resins, etc, with their mixtures with aliphatic glycidic ethers. The epoxy resin should have epoxy equivalent weight (EEW) from 150 up to 220 and viscosity from 2,000 up to 10,000 cps (25 C),
The composition according the present invention comprises as a liquid rubber low molecular weight linear carbon- or hetero-chain liquid at room temperature rubbers, such butadiene, butadiene-arcylonitril, butadiene-styrene, butadiene-isoprene, chlorisoprene, acrylic and silicone oligomers with terminated reactive able carboxyl, hydroxyl, amine and epoxy groups.
The composition according the present inventions comprises as an hardener primary amines with at least two terminates primary amine groups, Manish basic, organic or element-organic matter with at least two terminated carboxylic acid anhydrate groups.
The curing agents can be combined with curing accelerators in order to increase their curing activity.
The composition according the present inventions comprises a fluorine contained organic matter in which the surface loss energy in an organic solvent is less than 750×10−5 mJ, selected from a group, including
where: n=1-20;
X=—COOH, —CONH2, —CON(C6H5)2, —CH2OH.
b) CF3(CF2)nCOOH, where: n=7-9.
where: n=3-20.
The composition according this invention can comprise additionally functional different additives and mineral and organic fillers according to application requirement, including carbon and oxide nanotubes and fullerene.
The proposed epoxy-rubber composition has prepared by laminar mixing all the components according to following examples.
The composition was prepared by laminar mixing:
The composition was prepared by laminar mixing:
The composition was prepared by laminar mixing:
The composition was prepared by laminar mixing:
The composition was prepared by laminar mixing:
The composition was prepared by laminar mixing:
The composition was prepared by laminar mixing:
The composition was prepared by laminar mixing:
The composition was prepared by laminar mixing:
Adding the proposed fluorine organic matter in all the epoxy-rubber composition significantly increased their mechanical properties. The data of testing compositions according the examples I-IX is shown in the table.
According the data of table 1 proposed compositions have significant advantages in comparing with conventional composition.
