JPH0623235B2 - Epoxy resin composition curable at room temperature - Google Patents

Description

The present invention relates to a curable epoxy resin, and more particularly to a room temperature curable epoxy resin composition.

[Conventional technology]

Many so-called epoxy resins obtained by polymerizing a compound having an epoxy group in the molecule by the action of an acid catalyst or a base catalyst have been proposed. These are roughly classified into heat curing type, room temperature curing type, energy ray (ultraviolet ray, electron beam)
It can be divided into curing type. Generally, thermosetting epoxy resins use acid anhydrides or amines as catalysts,
Amine is used as a catalyst in the room temperature-curable epoxy resin. Further, an onium salt of Lewis acid is used as a catalyst in the energy ray curable epoxy resin.
In addition, a small number of room temperature-curable epoxy resins using an alkyl ester of phosphoric acid as a catalyst have been proposed.

[Problems to be solved by the invention]

The conventional epoxy resin has the following drawbacks. That is, the thermosetting epoxy resin has a drawback that energy required for curing is large and uneconomical, and that a heating device is required for curing. Room temperature-curable epoxy resins have a drawback in that the catalyst used often generates a gas harmful to the human body, or the catalyst that does not generate a harmful gas cures slowly. For example, JP-A-54
The method using an alkyl ester of phosphoric acid as a catalyst disclosed in JP-A-160456 has a drawback that the hydrolysis of the ester is slow and the epoxy resin cannot be completely cured. In addition, the energy ray-curable epoxy resin has a defect that not only a special device is required for curing but also the epoxy resin does not cure to a deep portion. Therefore, the inventors of the present invention arrived at the present invention as a result of extensive studies to solve the problems of the prior art. An object of the present invention is to provide an epoxy resin composition that does not generate a harmful gas to a human body and is rapidly cured at room temperature.

[Means for solving problems and their effects]

The purpose is to (i) at least one compound having an epoxy group (b) -OH groups of phosphoric acid silyl ester or polyphosphoric acid of the -OH group has been replaced by -OSiR ₃ group of phosphoric acid in one molecule - the molar ratio of substituted and all OSiR ₃ groups polyphosphate silyl ester this component in OSiR ₃ group and (b) the total epoxy groups in component 0.1: 1 to 10: 1 and comprising such an amount (provided that R Is a hydrogen atom or a monovalent organic group having 10 or less carbon atoms) at room temperature curable epoxy resin composition.

Achieved by

To explain this, the component (a) is the main component of the curable epoxy resin composition of the present invention, and the component (b) polymerizes, crosslinks and cures by the catalyst / crosslinking action of the component.
This component is a compound having at least one epoxy group in the molecule. The epoxy group here is the formula The organic group shown is exemplified by glycidyl group and 3,4 epoxycyclohexyl group. Such compounds include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, phenyl glycidyl ether, butyl glycidyl ether,
Monomers such as 3,4 epoxy cyclohexyl ethylene, glycidyl methacrylate, allyl glycidyl ether, 3,4 epoxy cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy Aliphatic epoxy resin such as resin, alicyclic epoxy resin, triglycidyl isocyanate, polyglycidyl ether, etc .; Epoxy resin obtained by reaction of aromatic, aliphatic or alicyclic carboxylic acid with epichlorohydrin; Spiro ring-containing epoxy resin A glycidyl ether type epoxy resin which is a reaction product of an O-allyl-phenol novolac compound and epichlorohydrin; an ortho position of each hydroxyl group of bisphenol A; Glycidyl ether type epoxy resin which is a reaction product of diallyl bisphenol compound having an allyl group and epichlorohydrin; brominated bisphenol A epoxy resin, epoxidized oil such as epoxidized soybean oil, 3-glycidoxypropyltrialkoxysilane, 3 Examples of such resins include, 4-epoxycyclohexylethyltrialkoxysilane, and a partial hydrolyzate of these silanes, an epoxy group-containing organopolysiloxane having a glycidyl group, an epoxycyclohexyl group, polyuritane, or polyester.

The structure, morphology and molecular weight of this component are not particularly limited, but in view of the miscibility with the component (b), it is preferably liquid at room temperature or under heating, or dissolved in an organic solvent.

Having a polysiloxane bond and a polyurethane bond in the main chain,
When a compound having an epoxy group as a functional group is used as this component, a flexible rubber-like cured product is obtained, and when a bisphenol A type epoxy resin or a bifunctional epoxy monomer is used as this component, a hard cured product is obtained. can get. In order to obtain the optimum pre-curing viscosity, curing speed, and physical properties after curing,
The combined use of two or more epoxy group-containing compounds is often an effective means. The component (b) is a component that characterizes the present invention and serves as a crosslinking agent for the component (a). This component converts the -OH group of phosphoric acid into -OSiR ₃
Is a substituted phosphoric acid silyl ester or -OH group polyphosphoric acid groups polyphosphate silyl ester was replaced with -OSiR ₃ group, but wherein R is an organic group having 10 or less carbon atoms the same or different. Specific examples of phosphoric acid or polyphosphoric acid mentioned here include polymetaphosphoric acid which is a condensate of orthophosphoric acid, pyrophosphoric acid, metaphosphoric acid, triphosphoric acid, tetraphosphoric acid and metaphosphoric acid. In the present invention, those silyl esters are effective as the component (b) regardless of the type of phosphoric acid and the molecular weight of the polyphosphoric acid, but low viscosity and easy handling, compatibility with the component (a) It is preferable to use a silyl ester of orthophosphoric acid because of its good reaction activity and mild reaction activity.

Further, if the number of phosphoric acid atoms in one molecule exceeds 6, the viscosity becomes too high and handling becomes difficult, which is not preferable. R is hydrogen or a monovalent organic group having 10 or less carbon atoms. R is an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group or an isobutyl group, a cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, an alkenyl such as a vinyl group, an allyl group or an isopropenyl group. Examples thereof include aryl groups such as groups, phenyl groups, tolyl groups, xylyl groups, and naphthyl groups. Moreover, some alkoxy groups may be contained as R. Also R
May be partially substituted with a hydroxyl group or halogen.
Such R may be the same or different. The carbon number of R is set to 10 or less, because when the carbon number of R exceeds 10, the activity of the curing reaction is remarkably lowered, which is not preferable. Further, it is preferable that 60% or more of R is a methyl group from the viewpoint of stability during synthesis of a phosphoric acid ester, ease of purification of a phosphoric acid ester, and low cost of raw materials.

The above-mentioned component (b) can be synthesized by a known synthesis method, but a typical example is the Journal of Organic Synthetic Chemistry 43 [12],
P. 1163 (1985), it is a method of heating and refluxing phosphorus pentoxide and hexamethyldisiloxane in benzene. If the starting material phosphorus pentoxide in this example is replaced with orthophosphoric acid, an orthophosphoric acid ester can be obtained. Further, a substituted phosphoric acid silyl ester can be easily obtained by substituting the methyl group in siloxane with another organic group.

In this component, in the presence of a compound having an active proton such as water or alcohol, the SiOP bond is cleaved to generate POH,
It is considered that this POH reacts with the epoxy group in the component (a) to carry out addition polymerization and crosslink. On the contrary, in a state where water, alcohol, etc. are cut off, the crosslinking reaction does not occur, and the composition has good storage stability.

The amount of this component added is such that the molar ratio of all OSiR ₃ groups in this component to all epoxy groups in component (a) is 0.1: 1 to 10: 1. The reason is that if the ratio is 0.1: 1, the curing becomes insufficient, and if it exceeds 10: 1, it is not substantially meaningful, and free phosphoric acid or polyphosphoric acid in the cured product becomes too much. This is because the physical properties of the cured product itself and surrounding metals and plastics are adversely affected. The preferable addition amount is such that the molar ratio is 0.6: 1 to 1.
The amount is 2: 1. The composition according to the invention comprises
It can be obtained by simply mixing the (a) component and the (b) component,
Planetary mixer, kneader mixer,
In addition to a normal mixing device such as a two-roll or three-roll type, a pot-type mixer, an extrusion material-type mixer, or the like that can mix in a state in which moisture is blocked is used.
When the component (a) is a thermosoftening resin, a mixing device having a heating device is useful.

The composition according to the present invention is capable of initiating curing by the action of moisture in the air and is a so-called one-component / moisture-curable curable composition, but different from other moisture-curable compositions. That is, water molecules are not required to be equivalent. In other words, once the action of water When the reaction of 1 occurs, the epoxy group is opened as follows.

The SiOH and COH thus created serve as a new proton source to break the next -SiOP- bond and produce -POH. In other words, once the reaction is initiated by water molecules,
The reaction proceeds in a chain, and in this respect, the composition according to the present invention is superior to other moisture-curable compositions.

In addition, by-products of the curing reaction of the composition according to the present invention,
R ₃ SiOH or R ₃ Si formed by combining two molecules of R ₃ SiOH
OSiR ₃ is the majority and it is widely known that it is a safe compound for the human body. In particular, when R is a methyl group, its safety is high, and from this point of view also, it is preferable that R is a methyl group.

The composition according to the present invention may be mixed with any additive as long as the object of the present invention is not impaired. For example, precipitated silica, dry silica, fused silica, natural silica, quartz powder, carbon black, calcium carbonate, sand, mica, talc, glass powder, hollow glass powder, hollow silica, graphite for the purpose of thickening or reinforcing. Fillers such as carbon fiber, asbestos, and alumina may be mixed. Further, powders of metals such as gold, silver, copper, aluminum, iron, nickel and titanium and oxides thereof may be added for the purpose of imparting electrical conductivity and thermal conductivity. Further, various coloring agents, flame retardants, and heat resistance improvers may be added. Further, polyamide, polysulfide, organopolysiloxane or the like may be added as a resin modifier.
Further, it may be diluted with an organic solvent such as toluene or trichlene, a non-reactive diluent or the like for the purpose of lowering the viscosity in order to improve the coating property or the coating property.

〔Example〕

The present invention will be described below with reference to examples. In the examples, "parts" means "parts by weight" and "%" means "% by weight". Further, various characteristics are values measured at 25 ° C. unless otherwise specified.

Example 1 15 parts of orthophosphoric acid (90% aqueous solution) and 60 parts of hexamethyldisiloxane were placed in a flask and refluxed at 110 ° C. while removing water distilled through a water separation tube to make the contents uniform and transparent. It was cooled at that time. Next, 80 to 90 ° C./5 mmHg fraction was obtained by vacuum distillation (hereinafter, this fraction is referred to as PSE-1). PSE-1 was confirmed to be orthophosphoric acid tris (trimethylsilyl) ester by NMR, gas chromatography and mass spectroscopy.

PSE Phenol A type epoxy resin [Shell Chemical Co., Ltd. Epicoat 828, epoxy equivalent 190] 10 parts and PSE
-1 by mixing 4.8 parts to form a 0.5 mm thin film and 25
When it was left under the condition of ° C and humidity of 50%, it was cured within 4 hours to obtain a plastic-like cured film.

Example 2 Instead of hexamethyldisiloxane in Example 1
Using 1,1,3,3 tetramethyldivinyldisiloxane,
As in Example 1, a fraction of 115 to 125 ° C./5 mmHg was taken. (Hereinafter, this fraction is referred to as PSE-2). PSE-
As a result of analysis, 2 was confirmed to be orthophosphoric acid tris (dimethylvinylsilyl) ester.

Warm bisphenol A type epoxy resin [Tobu Kasei Co., Ltd. Epotote YD011, epoxy equivalent 475] 10 parts, epoxy reactive diluent [Daicel Chemical Industry Co., Ltd. Celoxide 2021, epoxy equivalent 140] 5 parts to 80 ° C. After mixing and cooling to 40 ° C., 5 parts of PSE-2 was added and mixed. Curing started within 3 minutes after mixing, and a hard plastic-like cured product was obtained after 30 minutes.

Example 3 20 parts of phosphorus pentoxide was placed in a flask equipped with a reflux condenser, 38 parts of hexamethyldisiloxane and 80 parts of benzene were added, and the mixture was heated under reflux for 1 hour while stirring under an argon atmosphere. The obtained solution was concentrated with an evaporator to synthesize trimethylsilyl ester of polyphosphoric acid (hereinafter P
Called SE-3). Then the average formula (However, A is an epoxy equivalent of 3,4 epoxycyclohexylethyl group) and a polysiloxane having an epoxy equivalent of 260 was synthesized (hereinafter referred to as polymer 1). When this polymer 1 and the above PSE-3 were mixed under the conditions of a temperature of 25 ° C. and a humidity of 50%, they were cured immediately after mixing.

Example 4 Average formula (However, A is 3,4 epoxycyclohexylethyl group)
0) was synthesized and named as Polymer 2 (epoxy equivalent 3
100). A composition shown in Table 1 was prepared using Polymer 1, Polymer 2 and PSE-1 and formed into a sheet having a thickness of 1 mm, and allowed to stand for 72 hours in an atmosphere of a temperature of 25 ° C. and a humidity of 50% to give an elastic cured product. Obtained. The tensile strength and elongation of this cured product are also shown in Table 1.

[Effect of the Invention] In the present invention, since the component (b) is used as a curing catalyst and a crosslinking agent in the epoxy resin composition, it is characterized in that it cures in a short time at room temperature. In addition, it has the feature that it can be stored for a long time if the humidity and alcohol are cut off. Therefore, the curable epoxy resin composition of the present invention is cast in various industries such as electric and electronic industries, measuring instrument industries, automobile industries, machine industries, civil engineering and construction industries, container and packaging industries, medical equipment industries, food industries, and molding. As resin for glass, ceramic, metal, resin,
It is suitable as an adhesive or coating agent for substrates such as paper and fibers.

Claims (4)

[Claims] 1. A compound having at least one epoxy group in one molecule. (B) A phosphoric acid silyl ester in which the --OH group of phosphoric acid is replaced with an --OSiR ₃ group or a --OH group of polyphosphoric acid. the molar ratio of substituted and all OSiR ₃ groups polyphosphate silyl ester this component in -OSiR ₃ group and (b) the total epoxy groups in component 0.1: 1 to 10: 1 and comprising such an amount (provided that R is hydrogen or a monovalent organic group having 10 or less carbon atoms), which is an epoxy resin composition curable at room temperature. 2. An epoxy resin composition curable at room temperature according to claim 1, wherein R is a monovalent hydrocarbon group selected from an alkyl group having 10 or less carbon atoms, an aryl group and an alkenyl group. . 3. The room temperature-curable epoxy resin composition according to claim 2, wherein the alkyl group is a methyl group. 4. The epoxy resin composition curable at room temperature according to claim 1, wherein the polyphosphoric acid has 6 or less phosphorus atoms.