JP2000007788A - Crosslinked particle organic solvent dispersion and resin composition using the dispersion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crosslinked particle dispersion containing crosslinked particles which is easy to be added to and mixed with a resin composition and has excellent dispersibility and resin modified curing, and curability using the dispersion. A resin composition is provided. SOLUTION: The dispersion of the present invention has an average primary particle size (φn) of 30 to 500 n in a dry state.
m and a Tg of 0 ° C. or less,
A crosslinked particle organic solvent dispersion dispersed in an organic solvent (B) having a P value of 7.5 or more and 12.5 or less, wherein the average particle diameter (φd) of the crosslinked particles (A) in the dispersion is Is 150% or less of the average particle size (φn). Further, the curable resin composition of the present invention is manufactured using the dispersion of the present invention, and a cured product in which 70% or more of the number of crosslinked particles (A) contained in the composition is dispersed as primary particles. To form According to the resin composition of the present invention, a crosslinked resin (A) improves the toughness and adhesiveness, and provides a cured product having excellent heat resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a crosslinked particle organic solvent dispersion (hereinafter referred to as "crosslinked particle") which is excellent in improving the toughness of a resin and the adhesion to various materials, and is preferably used for modifying a resin. And a curable resin composition (hereinafter simply referred to as “resin composition”) produced using the dispersion and providing a cured product modified by the crosslinked particles in the dispersion. .).

[0002]

2. Description of the Related Art Thermosetting resins such as epoxy resins and phenol resins are excellent in many points such as dimensional stability, mechanical strength, electrical insulation properties, heat resistance, water resistance, and chemical resistance. It is suitably used for adhesives, paints, electrical insulating materials, semiconductor encapsulants, and the like. In particular, it is characterized by excellent adhesive strength to various materials such as metal, porcelain, and concrete, and high mechanical strength such as shear strength and tensile strength.

[0003] However, thermosetting resins often have drawbacks of low flexibility and low impact resistance, so that when used as an adhesive or a coating agent, they are easily peeled off from the surface to be coated, and cracks are generated. However, there is a problem that such a problem easily occurs.

[0004] In order to solve these problems, it has been attempted to modify the thermosetting resin by dispersing a rubber-like substance in the thermosetting resin, thereby improving the flexibility and impact resistance. Have been done.

Conventionally, the following method has been proposed as a method for modifying a thermosetting resin. (1) A method of mixing a liquid rubber such as acryl-nitrile-butadiene rubber having a reactive functional group with the epoxy resin (for example, Clayton A. May, Epoxy
See Resins, Marcel Dekker Inc. (1988). (2) A method in which an epoxy resin, a rubber component, and an organic peroxide are melt-kneaded to dynamically crosslink the rubber component during kneading. (See JP-A-8-143754.) (3) A method in which a powder obtained by coagulating and drying a crosslinked particle polymer latex is dispersed in an epoxy resin by a mixer such as a planetary mixer. (Japanese Unexamined Patent Publication No. Hei 6-33001
See No. 3 publication. )

[0006]

However, when a liquid rubber is used as a modifier as in the above method (1), mixing with a thermosetting resin is easy, but the epoxy resin and the rubber component are compatible. There is a problem that the heat resistance is greatly reduced due to melting. In addition, the development of the modifying effect requires the formation of a sea-island structure by phase separation of the rubber component during curing, but has a problem in that the morphology changes due to curing conditions and the like, causing variations in physical properties. . In the method of dynamically kneading the rubber component by melting and kneading the rubber component in the epoxy resin as described in the above (2), there is a problem that since the dynamic crosslinking is difficult to control, the physical properties tend to vary. In the method of dispersing the crosslinked particle powder in the epoxy resin as in the above (3), it is difficult to uniformly disperse the crosslinked particle powder in the form of primary particles. Tends to have an insufficient reforming effect. In addition, in this specification, "primary particle" refers to a particle which exists independently without aggregating with each other.

An object of the present invention is to provide a dispersion containing crosslinked particles which can be easily added to and mixed with a resin composition, and which has excellent dispersibility in the resin composition and the cured resin. It is to provide a dispersion. Another object of the present invention is a composition using the crosslinked particle dispersion,
An object of the present invention is to provide a curable resin composition in which various properties such as toughness and adhesiveness are improved by the effect of modifying the crosslinked particles, and which provides a cured resin product having excellent heat resistance.

[0008]

Means for Solving the Problems The present inventor has proposed an average particle diameter (φn) when dried in an organic solvent having a solubility parameter in a specific range and an average particle diameter observed in the organic solvent. A crosslinked particle dispersion in which crosslinked particles whose ratio to the diameter (φd) is equal to or less than a predetermined value is easily mixed and dispersed in a resin, and the crosslinked particles have very good dispersibility. I found that. Further, according to the curable resin composition using the crosslinked particle dispersion, toughness,
The inventors have found that the performance such as adhesiveness is remarkably improved, and that a cured product excellent in heat resistance can be easily obtained, thereby completing the present invention.

That is, the crosslinked particle dispersion according to claim 1 has an average primary particle size (φn) of 30 to 500 nm and a glass transition temperature of 0 ° C. or lower when dried. A) is a crosslinked particle dispersion dispersed in an organic solvent (B) having a solubility parameter of 7.5 or more and 12.5 or less, wherein the average particle size of the crosslinked particles (A) in the dispersion ( φd) is not more than 150% of the average particle diameter (φn).

[0010] A curable resin composition according to claim 2 is a resin composition produced by using the organic solvent dispersion of crosslinked particles according to claim 1, wherein the crosslinked particles contained in the composition. It is characterized in that 70% or more of the number of (A) forms a cured product dispersed as primary particles.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

(1) About Crosslinked Particles (A) As the crosslinked particles (A) in the present invention, those having a glass transition temperature (hereinafter, referred to as “Tg”) of 0 ° C. or less are used. When the Tg of the crosslinked particles (A) exceeds 0 ° C., a sufficient modifying effect cannot be obtained when the crosslinked particles (A) are used for modifying a curable resin. Although the lower limit of the Tg is not particularly limited, it is usually −80 ° C. or higher. Further, Tg is -80C to -0C, more preferably -60C.
It is preferable to use crosslinked particles (A) having a temperature of from -10 to -10C.

The composition of the crosslinked particles (A) is as follows.
Is not particularly limited as long as the Tg is 0 ° C. or lower. Preferably, a crosslinkable monomer having two or more unsaturated polymerizable groups (hereinafter, referred to as “crosslinkable monomer”) and one or more types selected so that the Tg of the crosslinked particles (A) is 0 ° C. or lower. Of the above (hereinafter referred to as "other monomers"). The other monomer is more preferably selected so as to include a monomer having a functional group other than the polymerizable group, for example, a functional group such as a carboxyl group, an epoxy group, an amino group, an isocyanate group, and a hydroxyl group.

Examples of the "crosslinkable monomer" include a plurality of polymerizable unsaturated groups such as divinylbenzene, diallyl phthalate, ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate and pentaerythritol triacrylate. Compounds having the same.

Examples of the above "other monomers" include butadiene, isoprene, dimethylbutadiene, chloroprene, 1,3-pentadiene, (meth) acrylonitrile, α-chloroacrylonitrile, α-chloromethylacrylonitrile, α-methoxyacrylonitrile, −
Unsaturated nitrile compounds such as ethoxyacrylonitrile, nitrile crotonic acid, nitrile cinnamate, dinitrile itaconate, dinitrile maleate, dinitrile fumarate, (meth) acrylonitrile, α-chloroacrylonitrile, α-chloromethylacrylonitrile, α-methoxy Unsaturated nitrile compounds such as acrylonitrile, α-ethoxyacrylonitrile, nitrile crotonic acid, nitrile cinnamate, dinitrile itaconate, dinitrile maleate, dinitrile fumarate, (meth) acrylamide, N, N′-methylenebis (meth) acrylamide , N, N'-ethylenebis (meth) acrylamide,
N, N'-hexamethylenebis (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N
-(2-hydroxyethyl) (meth) acrylamide,
Unsaturated amides such as N, N-bis (2-hydroxyethyl) (meth) acrylamide, crotonic amide, cinnamamide, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid Propyl, (meth)
Butyl acrylate, hexyl (meth) acrylate, lauryl (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth)
(Meth) acrylic acid esters such as acrylate, aromatic vinyl compounds such as styrene, α-methylstyrene, o-methoxystyrene, diglycidyl ether of bisphenol A, diglycidyl ether of glycol, etc. and (meth) acrylic acid, hydroxy Epoxy (meth) acrylate and hydroxyalkyl (meth) obtained by reaction with alkyl (meth) acrylate
Epoxy group-containing unsaturated compounds such as urethane (meth) acrylates, glycidyl (meth) acrylate, (meth) allyl glycidyl ether obtained by the reaction of acrylate and polyisocyanate, (meth) acrylic acid, itaconic acid, succinic acid unsaturated acid compounds such as β- (meth) acryloxyethyl, β- (meth) acryloxyethyl maleate, β- (meth) acryloxyethyl phthalate, and β- (meth) acryloxyethyl hexahydrophthalate; Amino group-containing unsaturated compounds such as dimethylamino (meth) acrylate and diethylamino (meth) acrylate, amide group-containing unsaturated compounds such as (meth) acrylamide and dimethyl (meth) acrylamide, hydroxyethyl (meth) acrylate, hydroxypropyl ( Meta) Acryle And the like can be exemplified hydroxyl group-containing unsaturated compound such bets.

The crosslinkable monomer constituting the crosslinked particles (A) in the present invention is preferably used in a range where the ratio of the crosslinkable monomer to all the monomers used for copolymerization is 1 to 20% by weight, more preferably 1 to 20% by weight. It is used in the range of 0.5 to 15% by weight, more preferably 2 to 10% by weight.

Crosslinked particles (A) contained in the dispersion of the present invention
Has an average primary particle size (φn) of 30 to 500 nm in a dry state, preferably 40 to 500 nm.
It is 200 nm, more preferably 50 to 150 nm. If the average particle size (φn) is less than 30 nm, the crosslinked particles are likely to aggregate, and it is difficult to uniformly disperse the particles in an organic solvent. On the other hand, the average particle size (φn) is 500 n
If m is exceeded, the effect of modifying the resin will decrease. The meaning of the “average particle size of the primary particles” will be described later in detail.

(2) Organic Solvent (B) The organic solvent (B) in the present invention has a solubility parameter (hereinafter, also referred to as “SP value”) of 7.5 or more and 12.
5 or less, and as long as this condition is satisfied, the dispersibility of the crosslinked particles (A) and the dissolution of the resin component to be modified by the crosslinked particles (A) (hereinafter, also referred to as “modified resin”). It can be appropriately selected in consideration of properties and the like. When the SP value of the organic solvent (B) is less than 7.5 or more than 12.5, problems such as reduced dispersibility of crosslinked particles and reduced solubility of the resin to be modified occur. . In addition, when a part or all of the organic solvent (B) is removed after mixing with the resin to be modified, etc., the solvent having a boiling point of 60 ° C. or more and 200 ° C. or less is used because the solvent is easily removed. It is suitably used as (B).

The organic solvent satisfying the above SP value includes
Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether;
Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and acetates of these ethers; ethyl acetate, propyl acetate, butyl acetate, ethyl lactate; Ethers and esters such as butyl lactate, 3-methyl-3-methoxybutanol, 3-methyl-3-methoxybutyl acetate, ethyl-3-ethoxypropionate; and toluene, xylene, dimethylformamide, tetrahydrofuran and the like. Can be.

The average particle size (φn) of the primary particles when the crosslinked particles (A) are in a dry state (hereinafter referred to as “average particle size in a dry state (φn)” or simply “average particle size (φn)”. ) Is 30 to 500 nm. On the other hand, in the crosslinked particle dispersion of the present invention, the average particle diameter (φd) of the crosslinked particles observed in the organic solvent (B) (hereinafter referred to as “average particle diameter in the dispersion (φd)” or simply “average particle diameter”) Diameter (φd) ”) is the average particle diameter (φ
n) is 150% or less.

Here, the "average particle size of the primary particles" in the dry state refers to the particle size of each of the particles constituting the aggregated particles when there are aggregated particles in which two or more particles are aggregated. It means the average particle size obtained in this way. The average particle size of the crosslinked particles “observed” in the organic solvent (B) is different from the “average particle size of the primary particles” when the above-mentioned aggregated particles are present. It means the average particle size obtained by determining the particle size by considering the two particles. Therefore, the average particle size (φd) in the dispersion increases as the aggregation ratio of the crosslinked particles in the dispersion increases. That is, the ratio between the average particle size (φn) in the dry state and the average particle size (φd) in the dispersion has a correlation with the degree of dispersion of the crosslinked particles in the dispersion. This indicates that the ratio increases. The average particle size (φd) can be determined by, for example, measuring the dispersed particle size by a light scattering method.

The ratio of the average particle diameter (φd / φn)
Varies depending on the degree of swelling of the crosslinked particles (A) in the dispersion. That is, the crosslinked particles (A) dispersed in the organic solvent (B) swell to different degrees depending on the affinity with the organic solvent (B) and the crosslink density of the particles. In general, the higher the affinity between the particles and the solvent, the greater the degree of swelling of the particles (dissolving if non-crosslinked particles)
Dispersibility tends to be good. This high affinity is
For example, the determination can be made based on the difference in SP value between the particles and the solvent. However, if the degree of swelling is too large, problems such as an increase in the viscosity of the dispersion and a decrease in workability, and the tendency of particles to aggregate easily occur. Therefore, in the present invention, while reducing the difference in SP value between the particles (A) and the organic solvent (B), it is preferable to suppress swelling by appropriately crosslinking the particles (A). In particular,
Use of crosslinked particles (A) having a composition in which the difference between the SP value of the organic solvent (B) and the SP value of the crosslinked particles (A) is 0 to 4.5 (more preferably 0.5 to 3.5). Is preferred.

The average particle size (φd) of the crosslinked particles in the dispersion of the present invention is 150% or less of the average particle size (φn) of the crosslinked particles (A) in a dry state, and preferably 12% or less.
0% or less, more preferably 110% or less. When the average particle size ratio (φd / φn) is 150% or less,
Since the proportion of the primary particles of the crosslinked particles (A) in the dispersion is large and the crosslinked particles (A) are not excessively swollen, the crosslinked particle dispersion excellent in dispersibility and resin modifying effect Becomes

The ratio of the crosslinked particles (A) to the organic solvent (B) in the dispersion of the present invention is usually 1 to 40% by weight for the crosslinked particles (A) and 99 to 60% for the solvent (B). % Is preferable in using this dispersion. When the proportion of the crosslinked particles (A) is less than 1% by weight, the effect of modifying the resin per addition amount of the dispersion is small, and a large amount of the dispersion of the crosslinked particles is required to exhibit the effect of modifying the resin. This is not preferred. If the proportion of the crosslinked particles (A) is more than 40% by weight, the fluidity of the crosslinked particle dispersion is reduced, which makes not only difficult to produce a uniform crosslinked particle dispersion but also the handling of the dispersion. Is also not preferable because it becomes difficult. The preferred viscosity of the dispersion of the present invention is 1000 cps / 25 ° C. or less, and 500 cp.
More preferably, it is s / 25 ° C. or less.

(3) Production Method of Dispersion The crosslinked particle dispersion of the present invention is produced, for example, by the following method. First, the method for producing the crosslinked particles (A) will be described in detail. The method for producing the crosslinked particles (A) is not particularly limited, and examples thereof include an emulsion polymerization method. That is, a monomer containing a crosslinkable monomer is emulsified in water using a surfactant, a radical polymerization initiator such as a peroxide catalyst or a redox catalyst is used as a polymerization initiator, and a mercaptan compound or a halogenated compound is used as necessary. 0 to 5 in the presence of a molecular weight regulator such as a hydrocarbon.
Emulsion polymerization is performed at 0 ° C., and after reaching a predetermined polymerization addition rate,
Crosslinked particles can be synthesized by adding a reaction terminator such as N, N-diethylhydroxylamine to terminate the polymerization reaction and then removing unreacted monomers of the polymerization system by steam distillation or the like. In addition, as a method of producing crosslinked particles without using a crosslinkable monomer, a method of adding a crosslinking agent such as a peroxide to the latex to crosslink the latex particles, or a method of forming a gel in the latex particles by increasing the polymerization conversion rate. And, further, a method of utilizing a functional group such as a carboxyl group and adding a crosslinking agent such as a metal salt to cause crosslinking within the particles.

Further, the latex containing the crosslinked particles obtained by emulsion polymerization is coagulated by a method such as salting out, washed with water and dried to obtain solid crosslinked particles (A).

When a nonionic surfactant is used as a surfactant during emulsion polymerization as a method other than salting out to coagulate the crosslinked particles, the nonionic surfactant is heated to a cloud point of the nonionic surfactant or higher and crosslinked. The particle components can also be coagulated.
Furthermore, even when polymerization is performed using a surfactant other than the nonionic surfactant, the crosslinked particle component can be coagulated by adding the nonionic surfactant after the polymerization and heating to a temperature higher than the cloud point. it can.

The surfactant used for producing the crosslinked particles (A) by emulsion polymerization is not particularly limited, but examples thereof include anionic surfactants such as alkylnaphthalenesulfonate and alkylbenzenesulfonate. Agents, cationic surfactants such as alkyltrimethylammonium salts and dialkyldimethylammonium salts, nonionics such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and fatty acid monoglycerides Either a system surfactant, an amphoteric surfactant, or a reactive emulsifier, or a mixture of a plurality of surfactants can be used.

The method for controlling the average particle size (φn) of the crosslinked particles (A) in the dry state is not particularly limited, but when synthesizing the crosslinked particles by emulsion polymerization, A method in which the number of micelles formed in the polymerization system is controlled by the amount, and thereby the particle size is controlled. The average particle size (φ
As a method for measuring n), the solvent is removed from a latex or a crosslinked particle dispersion obtained by emulsion polymerization to leave the crosslinked particles (A) in a dry state, which is observed by, for example, a transmission electron microscope (TEM). Method.

As a method for producing the crosslinked particle dispersion of the present invention, for example, the solid crosslinked particles (A) obtained by the above method or the like are masticated with a roll or the like to form a sheet, and if necessary, chopped. After that, a method of dispersing in the organic solvent (B) by introducing the mixture into the organic solvent (B) and stirring the mixture can be given. According to this method, the specific surface area is increased as compared with the block-shaped one, which is an industrial production form of the crosslinked particles (A), so that the dispersion time of the crosslinked particles (A) in the organic solvent (B) is shortened. It is possible to In addition, since the entanglement of molecular chains at the interface between the crosslinked particles is reduced by mastication, there is an advantage that the crosslinked particles (A) are easily dispersed in the organic solvent (B) into primary particles.

(4) Curable Resin Composition The crosslinked particle dispersion of the present invention is suitably used as a modifier for improving various properties such as toughness and adhesiveness of the curable resin. Claim 2 is a preferred example of a curable resin composition using the dispersion, and more than 70%, preferably more than 85%, of the number of crosslinked particles (A) contained in the composition. Preferably, 95% or more forms a cured product dispersed as primary particles.
If the proportion of the primary particles is less than 70%, the dispersibility of the crosslinked particles is insufficient, and it is difficult to obtain a sufficient effect of modifying physical properties such as adhesiveness. At this time, the “number of crosslinked particles (A) contained in the composition” refers to the number of particles individually counted also in the aggregated particles.

Here, the ratio of the primary particles among the crosslinked particles dispersed in the resin is, for example, 50,000 by TEM.
By counting the number of primary particles and the number of agglomerated particles (ie, the number of particles included in the agglomerated particles) from the TEM photograph of the cured resin taken at 2 ×, the ratio of primary particles = the number of primary particles / (Number of primary particles + number of aggregated particles) x 100
(%).

The resin to be modified suitable for the resin composition of the present invention is not particularly limited as long as modification with an elastomer component is desired in terms of toughness and adhesiveness, but diglycidyl is preferred. Ether type epoxy resin,
Novolak type epoxy resin obtained by reaction of epichlorohydrin with phenol novolak or cresol novolak, further, glycidyl ester type, glycidylamine type, epoxy resins such as alicyclic epoxy resin and halogenated epoxy resin, novolak type phenolic resin, Examples thereof include phenol resins such as resol type phenol resins.

[0034] In the resin composition of the present invention, the crosslinked particle dispersion has a proportion of the crosslinked particles (A) of usually 0.1 to 60% by weight based on the total weight of the resin to be modified and the crosslinked particles (A). It is blended so as to be in the range. If the proportion of the crosslinked particles (A) is less than 0.1% by weight, the modifying effect is insufficient, while 6
Exceeding 0% by weight is not preferred because the mechanical strength is greatly reduced.

Similarly to the definition of the average particle diameter (φd), when the average particle diameter of the crosslinked particles observed in the resin composition is defined as the average particle diameter (φc), the average particle diameter (φc) is It is preferable that the average particle diameter (φn) in a dry state is 200% or less, preferably 95% or more and 150% or less,
More preferably, it is 95% or more and 120% or less. When the average particle size ratio (φc / φn) is 200% or less,
Since the ratio of the primary particles of the crosslinked particles (A) in the resin composition is large and the crosslinked particles (A) are not excessively swollen, the number of the crosslinked particles (A) contained in the composition Of these, a cured product in which 70% or more is dispersed as primary particles can be easily obtained.

As a method for obtaining a resin composition using the crosslinked particle dispersion of the present invention, a method of directly charging a resin to be modified into the crosslinked particle dispersion and dissolving the resin to be modified in the organic solvent (B). Alternatively, a method of mixing a resin to be modified previously dissolved in an arbitrary organic solvent and a crosslinked particle dispersion can be exemplified. When the crosslinked particles (A) have a functional group that reacts with the functional group of the resin to be modified, these functional groups can be reacted by heating or the like as necessary.

The resin composition of the present invention obtained as described above can be used after removing a part or all of the organic solvent (B) by a method such as heating or depressurization, if necessary.

As additives, fillers such as silica, clay, calcium carbonate, mica and talc, coupling agents such as pigments, organic silane compounds and organic titanate compounds, xylene resin, tar, dibutyl phthalate (DBP), An extender such as a phosphoric acid ester, pine oil, benzyl alcohol, trimetate ester, diallyl phthalate monomer, xylene, and toluene, an antioxidant, and a curing agent depending on the resin can be added.

[0039]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following, "parts" indicates parts by weight.

Example 1 Emulsion polymerization was carried out at 10 ° C. according to the following polymerization recipe with the monomer composition shown in No. 1 of Table 1, and the polymerization addition rate was 90%.
The polymerization was stopped by adding 2 parts of hydroxylamine sulfate. After removing residual monomers from the obtained latex by steam distillation, 1.5 parts of an alkylated phenol is added as an antioxidant per 100 parts of solid content, coagulated with an aqueous solution of calcium chloride, washed with water, and then dried with a hot air drier. 9
After drying at 0 ° C. for 2 hours, polymer No. 1 (crosslinked particles (A)) was obtained. The average particle size (φn) of this polymer measured by TEM was 70 nm.

[Polymerization recipe] Monomer 100 parts Water 220 parts Sodium dodecylbenzenesulfonate 3 parts Potassium chloride 0.04 parts Sodium salt of ethylenediaminetetraacetic acid 0.09 parts Hydrosulfite 0.05 parts Tertiary dodecyl mercaptan 0.2 Parts Ferrous sulfate 0.016 parts Sodium formaldehyde sulfoxylate 0.05 parts Paramenthane hydroperoxide 0.05 parts

Next, the polymer No. 1 was wound around a 4-inch roll and masticated for 1 minute to form a sheet having a thickness of 2 mm. The sheet was cut into 1 cm square pieces, and then mixed in methyl ethyl ketone at the ratio shown in Table 2. This mixture was sealed in a flask, and stirred at 1000 rpm for 2 hours, whereby polymer N was dissolved in methyl ethyl ketone.
o. Thus, a crosslinked particle dispersion (a) in which 1 was dispersed was obtained. With respect to the obtained crosslinked particle dispersion, the dispersed particle size (average particle size (φd)) and viscosity of the crosslinked particles were measured by a light scattering method. Table 2 also shows the results of these measurements and the appearance of the dispersion.

Examples 2 and 3 In the same manner as in Example 1 except that the mixing ratio of the solvent and the polymer shown in Table 2 was used,
Crosslinked particle dispersions (b) and (c) were obtained.

(Comparative Examples 1 and 2) As shown in Table 2, SP
A crosslinked particle dispersion (d) was prepared in the same manner as in Example 1 except that hexane (SP = 7.3) and methanol (SP = 14.5) whose values were outside the range of the present invention were used as solvents.
An attempt was made to prepare (e), but no uniform dispersion was obtained.

Examples 4 to 6 Polymers Nos. 2 to 4 having the properties shown in Table 1 were obtained by the same polymerization method as in Example 1 using the monomer compositions shown in Table 1. Crosslinked particle dispersions (f), (g) and (h) were prepared in the same manner as in Example 1 except that Polymer Nos. 2 to 4 were used and the mixing ratio of the solvent and the polymer shown in Table 2 was used. ) Got.

(Comparative Examples 3 and 4) Polymers No. 5 and No. 6 having the properties shown in Table 1 were obtained by the same polymerization method as in Example 1 using the monomer compositions shown in Table 1. In addition, this polymer N
No. 5 is a polymer having a Tg of more than 0 ° C. (56 ° C.), and polymer No. 6 is a non-crosslinked (linear) polymer.
Using these polymers, a crosslinked particle dispersion (i) and a linear polymer solution (j) were obtained in the same manner as in Example 1 except that the mixing ratio of the solvent and the polymer shown in Table 2 was used. .

[0047]

[Table 1]

The method of Fedors (Source: R.
F. Fedors, Polym. Eng. Sci. , 1
4,147, (1974))
No. is 8.8, No. 2 is 9.3, No. 3 is 10.5,
No. 4 is 10.0, No. 5 is 11.4, and No. 6 is 9.6.

[0049]

[Table 2]

(Example 7) The crosslinked particle dispersion (a) obtained in Example 1 was added to an epoxy resin (Epicoat 828: manufactured by Yuka Shell Epoxy) in the composition shown in Table 3. After stirring the resulting mixture for 10 minutes,
After removing the solvent at 0 ° C. for 2 hours and then at 120 ° C. for 4 hours, the crosslinked particles No. 1 were added to the epoxy resin. Thus, a modified epoxy in which 1 was dispersed in the form of particles was obtained. About the obtained modified epoxy, the viscosity measurement and the dispersion particle diameter measurement of the crosslinked particle by the light scattering method were performed. From the TEM photograph of the cured product obtained by adding 10 parts by weight of triethylenetetramine to this modified epoxy and heating at 120 ° C. for 1 hour, the ratio of the number of primary particles in the cured product was measured. Further, the obtained modified epoxy was mixed with methyltetrahydrophthalic anhydride as a curing agent and a tertiary amine compound as a curing accelerator (trade name “Ancamine K54”, manufactured by AC I Japan Limited) in the composition shown in Table 3. And add 30
After stirring for a minute, a resin composition was obtained. The obtained resin composition was cured by heating at 90 ° C. for 2 hours and 120 ° C. for 1 hour to obtain a cured resin. A predetermined test piece was prepared from the cured product, and the fracture toughness value (K _IC ) and bending strength were measured by the following method, and Tg was measured by differential calorimetry (DSC).
I asked. The results are shown in Table 3.

Examples 8 to 12: Crosslinked particle dispersion (a)
Instead of the crosslinked particle dispersions (b), (c), (f),
A resin composition was obtained in the same manner as in Example 7, except that (g) and (h) were used, respectively. This composition and its cured product were evaluated in the same manner as in Example 7.

Comparative Example 5 The procedure of Example 7 was repeated, except that the crosslinked particle dispersion (i) consisting of the crosslinked particles (A) having a Tg of 56 ° C. was used instead of the crosslinked particle dispersion (a). Thus, a resin composition was obtained. This composition and its cured product were evaluated in the same manner as in Example 7.

Comparative Example 6 Example 7 was repeated except that the linear polymer solution (j) was used in place of the crosslinked particle dispersion (a).
Preparation of a modified epoxy was performed in the same manner as described above, but the subsequent evaluation could not be performed due to gelation by heating.

(Comparative Example 7) A modified rubber was prepared according to the composition shown in Table 3 using liquid rubber (HycarCTBN1300 × 13, manufactured by BF Goodrich) instead of the crosslinked particles. The resin composition was obtained and evaluated.

Comparative Example 8 An unmodified epoxy resin containing no crosslinked particles was evaluated in the same manner as in Example 1.

(Examples 13 to 15) Dicyandiamide as a curing agent and calcium carbonate as a filler were added to the modified epoxy obtained in Examples 1 to 3 in the composition shown in Table 4 and mixed with a roll. A resin composition was obtained. The adhesiveness (shear strength and T-peel strength) of the obtained resin composition was evaluated by the following methods.

Comparative Example 9 Example 13 was repeated except that the crosslinked particle dispersion (i) was used instead of the crosslinked particle dispersion (a).
A resin composition was obtained in the same manner as in Examples 15 to 15, and the adhesiveness of this composition was evaluated.

Comparative Example 10 Comparative Example 10 is an example in which a crosslinked particle was added in a dry state, not in a state of a “crosslinked particle dispersion”, to produce a resin composition. That is, the polymer No. 1 (15 parts by weight) is wound around a roll, and an epoxy resin (Epicoat 828, manufactured by Yuka Shell Epoxy) is used.
5 parts by weight were gradually added in five equal portions, and kneaded for about 2 hours until uniform, thereby obtaining a modified epoxy. Thereafter, the adhesiveness was evaluated in the same manner as in Examples 13 to 15.

Comparative Example 11 An unmodified epoxy resin containing no crosslinked particles was evaluated for adhesion in the same manner as in Examples 13 to 15.

[Evaluation method] (1) Fracture toughness value (K _IC ) A tensile test was performed at a tensile speed of 2 mm / min using a CT specimen in accordance with ASTM E399, and the fracture toughness value was measured. (2) Bending strength According to JIS K6911, a three-point bending test was performed at a displacement speed of 2 mm / min, and the bending strength was measured. (3) Tensile shear strength An adhesion test was performed according to the method of JIS K6850.
Using an SPCC steel plate (1.2 mmt) washed and degreased with acetone as an adherend, a test piece was prepared at a hardening condition of 170 ° C. for 30 minutes, a tensile test was performed at a measuring temperature of 23 ° C., and a tensile speed of 5 mm / min. The strength was measured. (4) T-type peel strength An adhesion test was performed according to the method of JIS K 6854.
Using an SPCC steel plate (0.8 mmt) washed and degreased with acetone as an adherend, a test piece was prepared at 170 ° C. for 30 minutes under hardening conditions, at a measurement temperature of 23 ° C. and a tensile speed of 100 mm /
Ten minutes, a tensile test was performed to measure the peel strength.

[0061]

[Table 3]

As can be seen from Table 3, as compared with the cured product of the unmodified epoxy resin composition (Comparative Example 8), the composition was obtained from the compositions of Examples 7 to 12 using the crosslinked particle dispersion of the present invention. The cured product has significantly improved fracture toughness, and has the same flexural strength and Tg as the unmodified epoxy resin. That is, according to the compositions of Examples 7 to 12,
A tough cured product with improved flexibility was obtained while maintaining the same strength and heat resistance as the unmodified epoxy resin. On the other hand, in Comparative Example 5 using the crosslinked particles (i) having a higher Tg than the range of the present invention, the effect of improving the fracture toughness value was insufficient. In Comparative Example 7 in which liquid rubber was added instead of the crosslinked particle dispersion of the present invention, the effect of improving the fracture toughness was low, and the strength and heat resistance were also reduced. In Comparative Example 6 using the linear polymer (j) instead of the crosslinked particles,
It gelled during the preparation of the resin composition.

[0063]

[Table 4]

As can be seen from Table 4, the cured products of the unmodified epoxy resin compositions (Comparative Example 11) were obtained from the compositions of Examples 13 to 15 using the crosslinked particle dispersion of the present invention. The cured product has a remarkably improved T-peel strength of 6 times or more, and has a shear strength of equivalent or more. On the other hand, in Comparative Example 9 using the crosslinked particles (i) having a higher Tg than the range of the present invention, the effect of improving the T-peel strength was insufficient. Then, in Comparative Example 10 in which the crosslinked particles were added as they were, not as a dispersion, the dispersibility of the particles was insufficient as can be seen from the fact that the ratio of the primary particles was as low as 45%. Was.

[0065]

According to the crosslinked particle dispersion of the present invention, since the crosslinked particles (A) are dispersed in an organic solvent (B) having a specific range of solubility parameter, mixing with a resin is easy, and The dispersibility of the crosslinked particles is very good. Since the crosslinked particles (A) are appropriately crosslinked unlike liquid rubber, they do not dissolve in the resin to be modified and form a sea-island structure.
Therefore, when the crosslinked particle dispersion of the present invention is used as a curable resin modifier, it is possible to improve the toughness and adhesion of the cured resin while maintaining other characteristic values such as heat resistance and strength. it can.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kenji Yasuda F-term (reference) 4J070 AB10 AB11 AB23 AD04 AE01 AE08 AE28 CA02 CA18 CB04 CB12 DA25 DB06 DB09 DB10 DC07 DC12 DC13

Claims (2)

[Claims] 1. A crosslinked particle (A) having an average primary particle size (φn) of 30 to 500 nm and a glass transition temperature of 0 ° C. or lower in a dry state, having a solubility parameter of 7.5 to 12 A crosslinked particle organic solvent dispersion dispersed in an organic solvent (B) having a particle size of not more than 0.5, wherein the average particle diameter (φ) of the crosslinked particles (A) in the dispersion is
d) The crosslinked particle organic solvent dispersion, which is 150% or less of the average particle diameter (φn). 2. A curable resin composition produced using the crosslinked particle organic solvent dispersion according to claim 1, wherein 70% or more of the number of crosslinked particles (A) contained in the composition. A curable resin composition characterized by forming a cured product in which is dispersed as primary particles.