JPH0545610B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Purpose of the invention [Field of industrial application] The present invention is applicable to anticorrosive paints for automobiles and ships, electrical insulating materials in the electronics field, structural materials reinforced with glass fibers, sealing materials, compatibilizing materials, and adhesives in civil engineering and construction. The present invention relates to a curable composition that forms a cured epoxy resin having a graft polymer structure having a specific different type of polymer segment in the molecule. [Prior art and its problems] Epoxy resin is used as an anticorrosive paint for automobiles and ships, for example, as an anticorrosive compounding agent for areas that are hidden due to the ebb and flow of the tide.
Primers and coal tar epoxy paints with high zinc content based on epoxy resins for corrosion protection on ships, electrical insulating materials for electronic and electrical parts, such as insulating materials for transformers, capacitors,
Encapsulation materials for semiconductors, laminates for electronic circuits, sealing materials for concrete pavement in a wide range of civil engineering fields, such as road construction and bridge construction, or laminating base materials such as glass fiber cloth, polyester fiber cloth, or mica paper. It is used in various structures and adhesives. However, it is known that epoxy resins contract due to the curing reaction or subsequent cooling and generate internal stress. This internal stress causes cracks, voids, peeling, or strength reduction in molds, seals, adhesives, lamination, paints, and the like. This reduction in internal stress is a problem in many fields, and to prevent this, fillers such as glass fiber, polyester fiber, mica, and silica are added, but the amount of filler added is There were limitations and internal stress could not be absorbed sufficiently. One of the reasons for this is the poor dispersibility of these fillers. Another method is to use a rubber material with a small elastic modulus, such as α,w-dicarboxylic acid type low molecular weight polybutadiene or poly(acrylonitrile-butadiene), or α,w-diepoxy type low molecular weight prebutadiene or poly(acrylonitrile-butadiene). There is a method of reducing the internal stress of a cured product by adding it, but a sufficient effect could not yet be expected. The reason for this is that this rubber is a so-called telechelic substance that has functional groups at the α and W-positions, so when it is cured, it is incorporated into the main chain of the cured product, that is, it enters into a block shape, reducing the degree of freedom of the rubber. ,
Therefore, it was not expected that the elastic modulus would decrease much. Flexible epoxy resins have recently been developed to address the above-mentioned drawbacks. This is a flexible polyalkylene or polyalkyl ether α, W
- It has been modified to diepoxide, but at present it does not have sufficient effects as mentioned above because of its telechroic structure. On the other hand, one of the drawbacks of epoxy resins is that they have poor compatibility. For example, when used as an adhesive, it seems to be versatile, but it does not adhere to crystalline materials, low polar materials such as PE, PP, PVC, acrylic, polystyrene resin, etc., and as a solution, Attempts have been made to improve adhesion through appropriate surface treatments and primer coating, but this is not the best method in practice due to the increased number of steps. In order to solve this problem, it was necessary to provide the epoxy resin with a segment that is highly compatible with the adhered material and capable of exerting a sufficient anchoring effect, but a good solution has not yet been found. This is the current situation. Furthermore, regarding the reduction of internal stress due to the addition of rubber, as mentioned above, as long as a telescopic rubber component is added, the rubber component enters the main chain and sufficient stress relaxation cannot be obtained. (B) Structure of the Invention [Means for Solving the Problems] The present inventors have completed the present invention as a result of studying the above-mentioned problems. That is, the present invention is a curable composition comprising an epoxy resin, a curing agent thereof, and a carboxyl group-containing macromonomer or an epoxy group-containing macromonomer described below. Carboxyl group-containing macromonomer: A macromonomer obtained by radical polymerization of a vinyl monomer, which has two carboxyl groups at one end of its main chain and has a number average molecular weight of 1,000 to 20,000. Epoxy group-containing macromonomer: 2 units in the above carboxyl group-containing macromonomer obtained by reacting an epoxy resin having two epoxy groups in one molecule at a ratio of 4 moles or more per 1 mole of the above carboxyl group-containing macromonomer. An epoxy group-containing macromonomer having a number average molecular weight of 1,000 to 20,000, in which one molecule of the above epoxy resin is bonded to each carboxyl group. Hereinafter, the above-mentioned carboxyl group-containing macromonomer will be referred to as a one-end dicarboxyl type macromonomer, and the epoxy group-containing macromonomer will be referred to as a diepoxy type macromonomer. [Function] Since the composition of the present invention contains a one-terminated dicarboxyl type macromonomer or a diepoxy type macromonomer derived therefrom (hereinafter also referred to as a terminal diepoxy type macromonomer), in these macromonomers, It is possible to obtain a unique cured epoxy resin having a graft structure in which branches are formed by the rubber component units of Even if the composition does not have a rubber component unit, it can be expected that the affinity with the filler will increase and its dispersibility will be improved, and as a result, the internal stress of the cured product will be sufficiently reduced. When used as an adhesive to bond difficult-to-adhere materials such as acrylic resins and polystyrene resins, for example, polymethyl methacrylate units, poly(acrylonitrile-styrene), which are highly compatible with acrylic resins, etc. ) units or polystyrene units, or for polystyrene resins, poly(acrylonitrile-styrene) units or polystyrene units, by creating a composition that is compatible with the adherend. It is possible to form a cured epoxy resin with a graft structure in which rich segments are introduced into the branches, and this is expected to provide even better adhesive strength. [One-end dicarboxyl type macromonomer] The one-end dicarboxyl type macromonomer used in the present invention is obtained by polymerizing a vinyl polymerizable monomer in the presence of a chain transfer agent having two carboxyl groups. Examples of vinyl polymerizable monomers include vinyl esters of organic acids such as vinyl acetate, styrene, P-methylstyrene, α-methylstyrene, vinylpyridine, ester methacrylate, acrylic ester, methacrylonitrile, acrylonitrile, and N-vinyl ester. pyrrolidone,
Unsaturated acid anhydrides such as maleic anhydride, N-substituted maleimides such as N-phenylmaleimide, etc., preferably styrene, styrene derivatives, (meth)acrylic acid esters, (meth)acrylonitrile, etc. alone or in combination of two or more. is used. Examples of chain transfer agents having two carboxyl groups include thiomalic acid. For reference, the structural formula of a single-end dicarboxylic macromonomer obtained when methyl methacrylate is used as the vinyl polymerizable monomer is as follows. However, n=10 to 200 In addition, as the polymerization method, any of the conventionally known solution polymerization method, bulk polymerization method, suspension polymerization method, and emulsion polymerization method in the presence of a known radical polymerization initiator may be used. However, since chain transfer agents are often soluble in water, solution polymerization or bulk polymerization is preferred, and solution polymerization is more preferred because chain transfer agents are often sparingly soluble in monomers. In the above method, a single-end dicarboxyl type macromonomer can be obtained by only one stage of polymerization reaction, but it can also be obtained by a two-stage reaction in which a reaction for introducing a terminal group is performed after polymerization. For example, vinyl polymerization is performed in the presence of mercaptoethanol or 3-mercapto-2-butanol as a chain transfer agent to obtain a vinyl polymer with a hydroxyl terminal at one end, and then this is reacted with trimellitic anhydride in the presence of a base catalyst. In this way, a macromonomer having a dicarboxyl type at one end can be obtained. For reference, the structural formula of the single-end dicarboxylic macromonomer obtained when the above two-step method is adopted using styrene as the vinyl polymerizable monomer and mercaptoethanol as the chain transfer agent is shown below. That's right. or However, in each case, n=10 to 200 [Production of diepoxy type macromonomer] The diepoxy type macromonomer in the present invention is an epoxy resin having two epoxy groups in one molecule (hereinafter referred to as It is obtained by reacting 4 moles or more of a diepoxy compound (also referred to as a diepoxy compound) in the presence of an amine compound. According to the reaction with the above molar ratio, a reaction occurs in which two molecules of the above epoxy resin are added per molecule of the one-terminated dicarboxylic macromonomer, and the reaction does not proceed any further, so an example of the chemical formula is as follows. A certain diepoxy type macromonomer having a structure in which two epoxy groups derived from the epoxy resin are bonded to one end of a vinyl polymer is synthesized. Example of chemical formula of diepoxy type macromonomer; (Example of diepoxy type macromonomer obtained from one-end dicarboxyl type macromonomer obtained using thiomalic acid as a chain transfer agent and bisphenol A diglycidyl ether) (In the formula, X is a bisphenol A residue, and Y is a vinyl polymer with a number average molecular weight of 1,000 to 20,000.) As an epoxy resin having two epoxy groups in one molecule, Those used in epoxy resin compositions can be used, such as the following. (a) Diglycidyl ether and di(β-methylglycidyl)ether of each of the following compounds. 2,2-bis(4'-hydroxyphenyl)propane (commonly known as bisphenol A), halogenated bisphenol A, bis(4-hydroxyphenyl)methane (commonly known as bisphenol F), resorcinol, ethylene glycol, polyethylene glycol , 2,2-bis(4'-hydroxycyclohexyl)propane. (b) Glycidyl ester and β-methylglycidyl ester of each of the following compounds. Adipic acid, sebacic acid, phthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid. (c) Epoxy resins synthesized by oxidizing intramolecular double bonds include Chitsonox 201, 221, 289, 206, 207X, etc. manufactured by Chitso Corporation. The epoxy resin, which is a raw material for synthesis of the diepoxy-terminated macromonomer, preferably has a polystyrene equivalent number average molecular weight of 3000 or less from the viewpoint of reactivity with the carboxyl group of the dicarboxyl-terminated macromonomer. An amine compound is used as a catalyst in the reaction between the one-terminated dicarboxylic macromonomer and the diepoxy compound. Examples of amine compounds include triethylamine, tripropylamine, benzylmethylamine, N-methylmorpholine, N,N-dimethyllaurylamine, N,N-
Dimethylaminomethylphenol, N,N-dimethylanilinetris(N,N-dimethylaminomethyl)phenol and its carboxylate salt, N,N
-dimethylaminoethylbenzene, triethylbenzylammonium chloride, tetrabutylammonium bromide, etc. Among them, benzyldimethylamine, N,N-dimethyllaurylamine, N,N-dimethylaniline, N,N
-dimethylaminomethylphenol, tris(N,N-dimethylaminomethyl)phenol and its carboxylic acid salts, and N,N-dimethylaminoethylbenzene are preferred. The optimum range of the reaction temperature varies depending on the type of amine compound used as a catalyst, but it is usually preferably 150°C or less. one terminal dicarboxyl type macromonomer, 1
The diepoxy type macromonomer obtained by the reaction of an epoxy resin having two epoxy groups in the molecule is obtained in the form of a mixture with the excess epoxy resin used in the reaction, but the diepoxy type macromonomer is obtained from the mixture. It may be isolated and used as a component of a curable composition, or it may be used as a component of a curable composition in the form of a mixture containing an epoxy resin. Practically speaking, it is also possible to add a curing agent to a diepoxy type macromonomer containing an epoxy resin, and further add an epoxy resin if necessary to obtain the curable composition of the present invention which provides a cured epoxy resin having a graft polymer structure. It's convenient. The molecular weight of the one-terminal dicarboxyl type macromonomer and the terminal diepoxy type macromonomer in the present invention is 1,000 to 20,000 on average, preferably 2,000 to 15,000. If the molecular weight is less than 1,000, the degree of polymerization as a polymer unit is too low and the physical properties of the macromonomer used as a raw material are not reflected in the physical properties of the cured product, which is undesirable.If it exceeds 20,000, the reactivity during curing decreases and the reaction system This is not preferable because it tends to cause disadvantages such as phase separation. The number average molecular weight of the above macromonomer is determined by gel permeation chromatography (hereinafter referred to as GPC).
) is the polystyrene equivalent molecular weight,
The measurement conditions are as follows. Apparatus: High performance liquid chromatography (for example, Toyo Soda Kogyo Co., Ltd., product name HLC-802UR) Column: Polystyrene gel (for example, Toyo Soda Kogyo Co., Ltd., product names 4000H8 and G3000H8) Elution solvent: Tetrahydrofuran (hereinafter referred to as THF) ) Outflow rate: 1.0 ml/min Column temperature: 40°C Detector: RI detector [Curable composition] The above one-terminated dicarboxyl type macromonomer and the terminated diepoxy type macromonomer can be used alone or in combination. They react with the epoxy resin in the presence of a curing agent for the epoxy resin to produce a cured epoxy resin having a graft polymer structure. As the epoxy resin, an epoxy resin having two epoxy groups in one molecule is suitable, and specifically, any of the various epoxy resins listed as raw materials that can be used when producing the terminal diepoxy type macromonomer can be used. Typical examples of curing agents for epoxy resins blended in the composition of the present invention include amine compounds and acid anhydrides, and acid anhydrides are preferred in compositions blended with one-terminal dicarboxylic macromonomers. It is a curing agent, and both acid anhydrides and amine compounds are used in compositions containing a terminal diepoxy type macromonomer. Specific examples of acid anhydrides that are curing agents include phthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, maleic anhydride, dodecylsuccinic anhydride, methylnadic anhydride, pyromellitic anhydride, and benzophenone anhydride. Tetracarboxylic acid, dichlorosuccinic anhydride, chlorendic anhydride, etc. can be used. In addition, other amine compounds that are curing agents include:
For example, diethylenetriamine, triethylenetetramine, diethylaminopropylamine, N-aminoethylpiperazine, benzyldimethylamine, tris(dimethylaminomethyl)phenol, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenyl sulfone, polyamide resin, dicyandiamide trifluoride. Examples include boron monoethylamine, menthanediamine, and xylene diamine. Other curing agents that can be used in the present invention include imidazoles, polysulfides, polymercaptans, polyamides, polyvinylphenols, and phenolic resins, which can also be used in the same way as acid anhydrides and amine compounds, and these Each curing agent can be used depending on the use and purpose. Each component in the composition of the present invention, that is, the terminal diepoxy type macromonomer or one-terminal carboxylic acid type macromonomer as a branch component in the cured epoxy resin having a graft polymer structure, the epoxy resin as the main component, and the acid anhydride as its curing agent Or the ratio of amine compound is [macromonomer]/
Weight ratio of [epoxy resin + curing agent] is 1/99 ~
It is preferably in the range of 60/40, and from 1/99 to
More preferably, the ratio is in the range of 40/60. Macromonomer is 1% by weight based on the total amount of these
If it is less than 60% by weight, the grafting effect cannot be expected, and it is not preferable, and if it exceeds 60% by weight, the curing reaction is significantly hindered, which is not preferable. The blending amount of the curing agent in the composition of the present invention may be appropriately determined in consideration of the amounts of epoxy groups and carboxyl groups in the composition. It is effective to add a curing catalyst to the composition of the present invention, and the addition of a curing catalyst is particularly effective when an acid anhydride is used as the curing agent. A curing catalyst can also be added to a composition that uses an amine compound as a curing agent. As the curing catalyst, any catalyst used in epoxy curable compositions can be used, and the amount added can be determined according to the amount in the composition. The method for preparing the composition of the present invention and its curing method also includes:
Methods known in the field of epoxy-based curing compositions can be applied, but to give an example of using an acid anhydride as a curing agent, a diepoxy-terminated macromonomer is previously mixed with an epoxy resin or an acid anhydride and a catalyst. A composition is prepared by mixing these, and is cured by heating at 120°C for 5 hours, but if you want to obtain a cured product as a molded product, further steps are required.
It is best to heat it at 150℃ for 15 hours. These curing conditions must be selected optimally depending on the use, purpose, type of catalyst, etc. [Example] The present invention will be explained in more detail by referring to Reference Examples, Examples, and Comparative Examples below. In addition, parts in each example represent parts by weight. Reference Example 1: Production of one-end dicarboxyl type poly(acrylonitrile-styrene) macromonomer Into a glass flask equipped with a stirrer, a reflux condenser, two dropping funnels, a thermometer, and a gas inlet, 125 parts of acrylonitrile, 375 parts of styrene, Charge 300 parts of butyl acetate, add 125 parts of acrylonitrile and 375 parts of styrene to one dropping funnel (referred to as dropping funnel A), and add 125 parts of acrylonitrile and 375 parts of styrene to the other funnel (referred to as dropping funnel B).
), 12.5 parts of azobisisobutyronitrile,
Thiomalic acid 30 parts, ethanol 70 parts, butyl acetate
180 parts of the mixture was added. After introducing nitrogen gas, the reaction solution was heated and kept at 90° C., and then added dropwise through dropping funnel A over 4 hours and dropping funnel B over 12 hours.
After heating for another 2 hours, the polymerization conversion rate of styrene is
95.8%, acrylonitrile polymerization conversion rate is 94.1%
It became. This product was vacuum dried at 80°C to obtain 980 parts of a solid one-end dicarboxylic macromonomer. The polystyrene equivalent molecular weight by GPC is
6250 (number average) and 14500 (weight average). Reference Example 2: Production of one-end dicarboxylic polybutyl acrylate macromonomer In a glass flask equipped with a stirrer, reflux condenser, dropping funnel, thermometer and nitrogen gas inlet,
Charge 400 parts of toluene and 4.6 parts of thiomalic acid, heat after introducing nitrogen, and maintain the liquid temperature at 75°C. A mixed solution of 72 parts of methyl ethyl ketone and 28 parts of ethanol was continuously added dropwise over 3 hours. After the reaction was continued for an additional 5 hours, the conversion rate of butyl acrylate was 98.2% as determined by gas chromatography. This product was desolventized in a vacuum at 80° C./mmHg using a rotary evaporator to obtain 502 parts of a viscous one-end dicarboxylic polybutyl acrylate macromonomer.
The polystyrene equivalent molecular weight by GPC was 5710 (number average) and 10400 (weight average). Reference Example 3: Production of one-end dicarboxylic polymethyl methacrylate macromonomer In a glass flask equipped with a stirrer, reflux condenser, dropping funnel, thermometer and nitrogen gas inlet,
Charge 400 parts of methyl ethyl ketone, 100 parts of MMA, 1.0 part of azobisisobutyronitrile, and 3.0 parts of thiomalic acid. 3 parts of a mixture of 4.0 parts of nitrile, 11.9 parts of thiomalic acid, 72 parts of methyl ethyl ketone, and 28 parts of ethanol.
Continuous dripping was carried out over time. After the reaction was continued for an additional 5 hours, the conversion rate of methyl methacrylate by gas chromatography was 95.4%. This product was dried in vacuum at 80℃, and a solid one-terminal dicarboxylic acid type polymethyl methacrylate macromonomer 500
I got the department. The polystyrene equivalent molecular weight by GPC was 5,800 (number average) and 12,000 (weight average). Reference Example 4: Production of a poly(acrylonitrile-styrene) macromonomer with a terminal diepoxy type In a glass flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas blowing tube, the one-terminated dicarboxyl type poly(acrylonitrile-styrene) obtained in Reference Example 1 was added. Acrylonitrile-
Styrene) macromonomer (acid value 0.370meq/g)
250 parts, Araldite as an epoxy resin whose main component is bisphenol A diglycidyl ether
GY-250 (manufactured by Ciba Geigy, epoxy amount
5.14meq/g, number average molecular weight 389), 250 parts (7 times the mole relative to the one-terminated dicarboxylic macromonomer), 500 parts of toluene, and 30 parts of 2,4,6-tris(dimethylaminomethyl)phenol were charged, and nitrogen was added. The reaction was carried out at 70°C for 2 hours with flowing water. The conversion rate of carboxyl groups as determined by acid value measurement was 99.5%. Next, this reaction solution was poured into methanol and the precipitate was dried under vacuum to obtain 270 parts of a solid terminal diepoxy type macromonomer. Polystyrene equivalent molecular weight by GPC is 7130 (number average) and 15200
(weight average). The molecular weight of the raw material macromonomer is 6250 (number average) and 14500 (weight average).
It is. Also, when we analyzed the epoxy group,
It was 0.311meq/g. Reference Example 5: Production of polybutyl acrylate macromonomer with diepoxy terminal end
0.369meq/g), and the other conditions were the same as those in Reference Example 4. The amount of Araldite GY-250 used was 7 times the mole per mole of the one-terminated dicarboxylic acid type macromonomer. After 2 hours at 70°C, the conversion rate of carboxyl groups was 99.1% due to the decrease in acid value. After that, the solvent was removed using a rotary evaporator, and the mixture consisted of 53.8% by weight of the terminal diepoxy type macromonomer, 40.5% by weight of unreacted epoxy resin (Araldite GY-250), and 5.7% by weight of the catalyst (2,4,6-tris(dimethylaminomethylphenol)). The product was obtained as a viscous liquid.The polystyrene equivalent molecular weight of the terminal diepoxy type macromonomer by GPC was:
They were 6700 (number average) and 11200 (weight average).
The molecular weight of the raw material, the one-terminated dicarboxyl type macromonomer, is 5710 (number average) and 10400 (weight average).
It is. Reference Example 6: Production of terminal diepoxy type polybutyl acrylate macromonomer N,N-dimethyllaurylamine 10 as catalyst
A reaction product containing a diepoxy-terminated macromonomer as a main component was obtained in the same manner as in Reference Example 5 except that After reacting at 70℃ for 4 hours, the conversion rate of carboxyl group due to decrease in acid value was 99.6
When this reaction solution was analyzed by GPC, the molecular weight in terms of polystyrene was 6550 (number average).
and 11,000 (weight average). The molecular weight of the raw material, the one-terminal dicarboxylic macromonomer, is
5710 (number average) and 10400 (weight average). Examples 1 to 7 and Comparative Example 1 Using the one-terminal dicarboxylic acid type macromonomer or the terminal diepoxy type macromonomer obtained in each reference example, a curable composition was prepared using this, an epoxy resin, a curing agent, and a curing catalyst. This was also cured to produce a cured product having a graft polymer structure. That is, after thoroughly mixing and dispersing the components shown in Table 1, the mixture was heated at 120°C for 5 hours and then at 150°C for 15 hours to completely cure, and the physical properties of the cured product were measured. In addition, as the macromonomer of Reference Example 5,
The reaction product solution after solvent removal was used as it was. The results are shown in Table 1.Among the physical properties of the cured product, the improvement in the flexural modulus was particularly remarkable, and the improvement brought about by the graft polymer structure in the cured product given by the blending of the macromonomer. The quality effect is significant.

【table】

[Table] (C) Effects of the Invention The composition of the present invention has excellent curability, and by blending a single-end dicarboxylic macromonomer or a diepoxy-terminated macromonomer, a cured epoxy resin having a graft polymer structure can be easily produced. The resulting cured product is composed of different components: a branch component derived from the macromonomer and a main component derived from the epoxy resin and its curing agent. Depending on the degree, the affinity with the filler blended into the epoxy resin composition improves and its dispersibility improves, and as a result, internal stress can be reduced, and macromonomers having rubber-like units are used. By doing so, the internal stress of the cured product can be reduced without necessarily adding a filler. Therefore, the composition of the present invention is useful in various fields in which epoxy resins are used, where problems caused by internal stress have been considered problematic. Furthermore, in fields where cured products are strongly required to have adhesion and adhesion to the substrate, the composition of the present invention, which contains a macromonomer that has high affinity with the substrate, satisfies this requirement. Is possible. Thus, the composition of the present invention can be suitably used in a wide range of fields such as paints, electrical insulating materials, sealants, adhesives, etc.

Claims (1)

[Scope of Claims] 1. A curable composition comprising an epoxy resin, a curing agent thereof, and the following carboxyl group-containing macromonomer or epoxy group-containing macromonomer. Carboxyl group-containing macromonomer: A macromonomer obtained by radical polymerization of a vinyl monomer, which has two carboxyl groups at one end of its main chain and has a number average molecular weight of 1,000 to 20,000. Epoxy group-containing macromonomer: 4 epoxy resins having 2 epoxy groups in 1 molecule per 1 mole of the above carboxyl group-containing macromonomer.
An epoxy group-containing macro having a number average molecular weight of 1000 to 2000, in which one molecule of the epoxy resin is bonded to each of the two carboxyl groups in the carboxyl group-containing macromonomer obtained by reacting in a molar or higher ratio. monomer.