JPS6340205B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition for water dispersion and a dispersion thereof. More specifically, the present invention mainly relates to an addition or condensation polymerization reaction between an organic compound having an alcoholic hydroxyl group or a phenolic hydroxyl group and an organic compound having a group selected from the group consisting of a carboxyl group, an isocyanate group, a glycidyl group, and an aldehyde group. From a specific blending ratio of the saturated polymer obtained by the method, an α,β-unsaturated carboxylic acid ester having one aminic nitrogen atom in the ester residue, and a monomer having one ethylenically unsaturated bond. The present invention relates to a water-dispersible resin composition obtained by irradiating a mixture with an electron beam and an aqueous dispersion thereof. Heat-reactive synthetic resins such as epoxy resins, polyester resins, and urethane resins are mechanically
Due to its excellent electrical and thermal properties, demand for it has been increasing steadily in recent years.
These resins are normally used as an organic solvent as a medium, but from social viewpoints such as environmental protection and resource conservation, there is an urgent need to switch to an aqueous medium.
For this reason, the development of techniques for making these resins water-soluble or water-dispersible is being carried out in various fields. So far, the technologies for making synthetic resins water-soluble or water-soluble include (1) introducing many hydroxyl groups and ether groups into the resin to make it water-soluble, and (2) neutralizing carboxyl and amino groups in the resin. Neutralize with agent,
(3) A method of forcibly emulsifying the resin in a medium mainly composed of water using a surfactant (forced emulsification method); (4) Grafting a polymerizable hydrophilic vinyl compound. method (hydrophilic group grafting method)
is proposed. However, the aqueous dispersion obtained by methods (1) and (2) has a low molecular weight (1) to make it water-solubilized, and when made into a thin film, it has poor flexibility and mechanical and physical problems. (2) It contains a large amount of hydrophilic groups in the resin, so its water resistance is extremely poor, and its uses are extremely limited. Furthermore, the aqueous dispersion obtained by the forced emulsification method (3) has poor stability, and the resin and water are likely to separate. (b) Since a large amount of surfactant is used, there are drawbacks such as not only poor water resistance and adhesion of the thin film but also the surfactant eluting from the film. On the other hand, the hydrophilic group grafting method (4) is excellent in imparting self-emulsifying ability to water, but the monomers that can be used are generally limited and the reaction operation is complicated, so there are no specific implementation methods. There are relatively few methods. A relatively recent proposal, for example, as in JP-A-1228-1228, involves grafting an epoxy resin with a water-soluble vinyl compound (carboxylic acid) using an organic peroxide initiator in an organic solvent and dispersing it in water. There is a way to do it. However, this method
○ Since the reaction is carried out in an organic solvent, a large amount of organic solvent is required and separation and removal of the solvent and residual monomer is difficult. As a result, the physical properties of the film deteriorate. There are drawbacks such as.
As a method to solve these drawbacks, a mixture of an epoxy resin and a polymerizable monomer group including a polymerizable unsaturated monomer having a carboxyl group is irradiated with an electron beam to graft the mixture to form an aqueous dispersion. (Unexamined Japanese Patent Publication 1983)
−32551) was recently proposed. All of these grafting methods provide anionic water-dispersible resins. On the other hand, in the case of cationic emulsions, especially in the case of epoxy resins, when thermochemical graft polymerization is used, a reaction between cationic unsaturated monomers and epoxy rings occurs during graft polymerization, resulting in crosslinking. and the purpose cannot be achieved. When performing electron beam grafting, the inventors of the present invention (1) can perform the reaction without a solvent or under high viscosity. (2) For this reason, a high molecular weight substance is generated, which can impart strong physical properties. (3) High grafting efficiency and excellent dispersion ability. (4) Polymerizable monomers that cannot be used using thermochemical methods can be stably handled. As a result of intensive research in order to obtain a chemically stable water-dispersing resin with excellent water resistance, solvent resistance, and physical properties, we found that a specific saturated polymer and ester residue that are insoluble in water were used. When a mixture mainly consisting of α,β-unsaturated carboxylic acid esters containing one amino nitrogen atom in the group was solidified by irradiation with an electron beam, the mixture was dissolved in an appropriate solvent and then acidic water was added. A stable aqueous dispersion can be obtained, and a thin film made from this aqueous dispersion has excellent water resistance, solvent resistance, and physical properties. They found that it can also be applied to other areas, and have completed a new technology that solves the drawbacks of the conventional technology. The basic method for producing the composition of the present invention is to use a specific saturated polymer (hereinafter sometimes abbreviated as "component A") and an α,β-containing ester residue containing one amine nitrogen atom. It consists of forming a mixture mainly consisting of unsaturated carboxylic acid ester (hereinafter sometimes abbreviated as "component B") into a suitable shape and irradiating it with an electron beam. The basic method for producing the composition of the present invention is as described above.
A radically polymerizable monomer having one ethylenically unsaturated bond in one molecule (hereinafter sometimes abbreviated as "component C") is blended into the system consisting of "component B" and "component B", and the mixture is shaped into an appropriate shape. It can also be produced by modifying a saturated polymer into a water-dispersible saturated polymer by irradiating it with an electron beam. "Component C" used in this case is used to help dissolve component B into "component A." By using "component C" in combination, the resulting resin composition can be more easily dispersed in water. In the present invention, when the mixture is irradiated with an electron beam, a portion of the monomer is graft-polymerized to the saturated polymer, and a solid in which the graft polymer, non-grafted polymer, and non-grafted saturated polymer are uniformly dispersed microscopically is formed. can get. “Graft polymer” referred to here
is a product in which nitrogen compound esters of acrylic acid and methacrylic acid are graft-polymerized onto a saturated polymer, and it functions as an emulsifier, allowing the non-grafted saturated polymer to be stably dispersed in an aqueous solvent. Furthermore, the non-grafted polymer referred to herein is one in which a monomer is addition-polymerized to a saturated polymer without being graft-polymerized, and is soluble or dispersible in water. Therefore, the resin composition produced by the above-mentioned irradiation is composed entirely of water-dispersible components. Hereinafter, the content of the present invention will be explained in more detail. The saturated polymer ("component A") referred to in the present invention is as follows: (1) Known epoxy resins such as so-called bisphenol A-type diglycidyl ether can be used; It is desirable to contain one or more groups. (2) Among alkyd resins, saturated polyester resins are obtained mainly from saturated dihydric alcohols and saturated dibasic acids. (3) Among urethane resins, saturated polyurethane resins are obtained by blocking isocyanates obtained mainly from saturated dihydric alcohol and saturated polyisocyanates. (4) Saturated polyphenol resins represented by resol-type phenolic resins and resol-butyral resins that are etherified with monohydric alcohols. (5) A polyacetal resin obtained by a condensation reaction between polyvinyl alcohol, typified by so-called polyvinyl butyral resin, and an alkyl aldehyde. The proportion of these components in the composition is
It is 70-98% by weight. The α,β-unsaturated carboxylic acid ester (component B) containing one aminic nitrogen atom in the ester residue, which is an essential component of the present invention, refers to
2-N,N-dimethylaminoethyl group, 2-N,
N-diethylaminoethyl group, 2-N,N-dibutylaminoethyl group, 3-N,N-diethylaminopropyl group, 2-N,N-dibutylaminopropyl group, 2-N,N-dibutylaminopropyl group, 3 -N,N-dibutylaminopropyl group, 2
-N,N-di-t-butylaminoethyl group, 2-
Examples include α,β-unsaturated carboxylic acid esters having an N-ethyl-N-(hydroxyethyl)aminoethyl group, a 3-N,N-dimethylamino-2-hydroxypropyl group, and the like. Both of these are dissociated by adding acidic water, giving positive charges to the grafted polymer chains and non-grafted polymer chains. The proportion of these components in the composition is 2
-30% by weight, preferably 3-20% by weight. This means that if it is less than 2% by weight, it will be difficult to redisperse it in water, and if it is more than 30% by weight, the stability after dispersion in water will be poor. Further, as other polymerizable ethylenically unsaturated monomers, those that are compatible with the saturated polymer are desirable and are used to help dissolve the monomer in the saturated polymer. Specific examples of "component C" include styrene, β-methoxystyrene, α-methylstyrene, acrylic ester, methacrylic ester, acrylonitrile, and methacrylonitrile. In the compositions of the present invention, "Component C" is used in an effective amount of up to 48% by weight. This is because if it exceeds 48% by weight, it cannot be water-dispersed. When "component C" is used in the present invention, a mixture of "component A" and "component C" is prepared, and "component B" is added to the mixture. When making a mixture of "component A" and "component C", if a low molecular weight saturated polymer has low viscosity, it can be heated to 60-70℃ and stirred using a normal stirrer. Since polymers have high viscosity, a kneader or the like is used. At this time
It may be heated to an appropriate temperature of 100°C or less. When adding "component B" to a mixture of "component A" and "component C", if a reaction between "component A" and "component B" is expected, the temperature should be kept at 50℃ or below to prevent this reaction. It is desirable to keep the temperature low. In addition, the above operations may be performed in the presence of an inert gas in order to promote the reaction by electron beams. The mixture of “components A”, “B” and “C” is
It is formed into a sheet with a thickness of 0.1 mm and is covered with polyester film and then irradiated. The thickness of the entire sheet is determined by the range of the electron beam of the electron accelerator used. For electron beam irradiation, the dose rate is 1×10 ⁴ to 3×10 ⁶ rad/sec, preferably 0.5 at a temperature of -50 to 50°C.
Deliver a total dose of 5-50M rad at ~25M rad/sec. The dose rate is limited not only by the performance of practical equipment and the need for a long reaction (irradiation) time, but also by the reaction aspect. That is, if the dose rate is too low, the molecular weight will increase significantly or a crosslinking reaction will occur, resulting in gelation and water dispersion becomes impossible. Furthermore, at high dose rates, heat generation due to irradiation occurs rapidly, or the concentration of radicals increases, which increases the number of recombination reactions, making it difficult to control the reaction or causing gelation. The irradiation temperature was limited because cooling to below -50°C is not only disadvantageous in terms of cooling costs but also reduces the reaction rate, and irradiation above 50°C may cause a crosslinking reaction. be. The dose rate is limited by the performance of practical equipment, but as for the irradiation dose, a dose of 5M rad or less will result in a large amount of residual monomer, and conversely, a large dose of 50M rad or more is not necessary and would rather cause cross-linking etc. cause harm. The solidified product obtained by irradiation is reduced to an average particle size of 1 by an appropriate method.
A water dispersion is obtained by pulverizing the powder to a size of about mm or less, dissolving or swelling it in an organic solvent, and mixing and stirring acidic water therein. The organic solvent used here is
One or more of n-butanol, cyclohexanone, butyl cellosolve (ethylene glycol monobutyl ethyl), tetrahydrofuran, etc., preferably containing 25% by weight or more of n-butanol, and its composition is based on the "B" and "C" components used. ” is selected according to the composition of the resin, and the amount added is usually
The amount is from 30 parts by weight to 100 parts by weight per 100 parts by weight. Dissolution in an organic solvent and dispersion in water are preferably carried out at a temperature of 50°C or lower. This is because the modified resin composition in the present invention may inherently have self-curing properties. The amount of water added is usually 30 to 700 parts by weight, preferably 100 to 500 parts by weight, per 100 parts by weight of the powder. What is particularly important in this dispersion process is that the saturated polymer modified by the electron beam irradiation treatment described above has particularly excellent emulsifying power, and even saturated polymers that have not been subjected to electron beam irradiation treatment can be dispersed in water. be. For this purpose, the electron beam irradiated saturated polymer powder and the untreated saturated polymer are thoroughly mixed, an organic solvent is added thereto to dissolve or swell the mixture, water is added thereto, and the mixture is stirred. The amount of the untreated saturated polymer that can be dispersed depends on the structure and amount of the nitrogen compound esters of acrylic acid and methacrylic acid used in the electron beam irradiation treatment, as well as the irradiation conditions. It is 20 to 300 parts by weight per 100 parts by weight. EXAMPLES Hereinafter, the effects of the present invention will be explained in more detail with reference to Examples and Reference Examples. The formulations, evaluation methods, etc. in Examples are as follows. (1) All formulations are by weight. (2) Electron beam irradiation conditions are shown in the following order: acceleration, voltage, dose rate, irradiation temperature, and total dose. (3) Among polymer properties, molecular weight is manufactured by Toyo Soda.
The peak positions of the backbone polymer and acrylic resin according to HLC802UR are shown. (4) Grafting ratio among polymer properties is measured by fractionation method. The solvents used are tetrahydrofuran, methyl alcohol, and carbon tetrachloride, expressed in weight percent relative to the backbone polymer. (5) Neutralization and dilution in emulsion are based on weight. (6) Measurement of non-volatile content during emulsion
By heating and drying at 120℃ for 380 minutes. (7) Among the characteristics in emulsion, the values of viscosity and viscous diameter are measured at 25℃ and are shown in centipoise (cp) and micron millimeters, respectively.The particle size measurement is calculated from the rapid aggregation rate using the stopped flow method. did. (8) Among the emulsion properties, stability is determined by visual sedimentation. Emulsion system pH at this time
was between 7.4 and 8.8 in Examples 1 to 12. (9) Performance comparison was performed by spray coating the obtained emulsion on a tin plate, drying at 160°C for 20 minutes, and then testing. Gel fraction is the weight percentage of the residue after acetone extraction, hardness is pencil hardness, and adhesion (including water-resistant adhesion) is determined by the cross-cut peeling test using cellophane tape.
Solvent resistance is shown in the results of a xylol wiping test (10 reciprocations). The main polymer and other resins used in this example were Epicoat from Ciel Chemical, polyvinyl butyral from Denki Kagaku Kogyo, and phenolic resin from Hitachi Chemical.
The polyester used was made by Mitsui Toatsu, the 60% amino resin was made by Hitachi Chemical, and the Saomel 370 was made by American Cyanamid. Example 1 After stirring, 70% of epoxy resin (Epicote 1009, manufactured by Ciel Chemical) was placed in a 200 ml four-necked glass flask equipped with a nitrogen gas inlet tube, a thermometer, and a cooling tube.
g, methacrylic acid 5g, ethyl acrylate 10g,
Charge 10g of isobutyl methacrylate, stir at 67°C for about 1 hour, cool to room temperature, and add 5g of isobutyl methacrylate.
Add 2-N,N-dibutylaminoethyl methacrylate and continue stirring for another 30 minutes in a nitrogen gas atmosphere to obtain a highly viscous fluid in which components "A", "B", and "C" are uniformly mixed. Ta. Add this mixture to a thickness of 0.1
It was sandwiched between two sheets of mylar film with a width of 30 cm and a width of 30 cm, and was formed into a circular sheet with a thickness of 2 mm. The obtained sheet-like mixture was placed on an ice bath and heated using a cascade type electron beam accelerator (Dynamitron) at an electron beam energy of 1.5 MeV and a dose rate of 5×.
10M rad was irradiated at 10 ⁵ rad/sec. This irradiated object was in the form of a transparent, hard sheet, and could be easily peeled off from the Mylar film. The monomer conversion rate of the obtained modified resin was 98.0%, and the grafting rate (weight increase) to the epoxy resin was 14.
%, the molecular weight (peak value) of the epoxy resin is 15000,
The molecular weight (peak value) of the acrylic copolymer is approximately 2×
It was 10 ⁵ . Next, use a crusher to crush the irradiated object into 1
It was finely crushed to a size of mm or less. 50g of this powder
was placed in a 500 ml flask, 40 g of a solvent containing a mixture of butanol, cyclohexanone, and butyl cellosolve at a ratio of 2:1:1 was added, and the mixture was stirred and dissolved at room temperature using a 4-blade stirrer. Then 15%
Add 22.5g of acetic acid aqueous solution and stir, then add 125g of water.
It was added gradually and stirred vigorously to obtain an aqueous dispersion. Water dispersion has a nonvolatile content of 21.5%, a viscosity of 2.7cp, and an average particle size.
It exhibited properties of 0.25 μm, and remained stable with no precipitate formation observed even after being left at room temperature (25° C.) for May. Example 2-8 In the method of Example 1, a graft reaction was carried out by changing the composition and blending of the epoxy resin and monomer, and the electron beam irradiation conditions. These conditions, the properties of the modified resin, the dispersion method when using 100 parts by weight, and the properties of the emulsion (water dispersion) were
Shown in the table.

【table】

[Table] Reference Example 1 Table 2 shows the performance of baked films using the aqueous epoxy resin dispersions obtained in Examples 1, 4, and 6 and examined by the following method. Incidentally, the grafting reaction to the epoxy resin was carried out using benzoyl peroxide with the same composition as in Example 1 at a reaction temperature of 60°C, but it resulted in gelation. Therefore, for performance comparison, a commercially available amino-acrylic-epoxy A resin cation emulsion was used. Spray the emulsion onto the tin plate,
The test was performed after drying at 160°C for 20 minutes. Gel fraction is the weight percentage of the residue after acetone extraction, hardness is the result of a pencil, hardness and adhesion are the results of a cellophane peel test (including water resistant adhesion), and solvent resistance is the result of a xylol wiping test (10 reciprocations). is shown. The water resistance test was conducted at room temperature for 35 days.

[Table] Examples 9 to 12 Graft reactions were carried out under the same monomer composition and irradiation conditions as in Example 8, using polyurethane, phenol, polyester, and polyacetal instead of the epoxy resin. All of the modified resins could be water-dispersed using the same method as in Example 1, and baked films with excellent performance could be obtained from the water-dispersed products. The contents are shown in Table 3. Comparative Examples 1-4 Grafting reactions corresponding to Examples 9-12 were carried out in butyl cellosolve (100 parts by weight) using 2 parts of benzoyl peroxide as an initiator at 60°C for 7 hours. The results are shown in Table 4. It was revealed that when a phenolic resin was used, almost no polymerization occurred, and when a polyester resin was used, the reactants underwent phase separation and almost no grafting occurred. Water dispersion of polyurethane and polyacetal was performed, but the properties of the resulting dispersion were inferior to those obtained using the electron beam method, and the baked film had phase separation (white turbidity) and was not worth evaluating. .

【table】

【table】

[Table] * Part of the reaction solvent is removed from the reactants under reduced pressure.

Claims (1)

[Scope of Claims] 1 (a) an organic compound having an alcoholic hydroxyl group or a phenolic hydroxyl group, and (b) a carboxyl group,
70 to 98% by weight of a saturated polymer obtained by addition or condensation polymerization reaction with an organic compound having a group selected from the group consisting of an isocyanate group, a glycidyl group, or an aldehyde group, and an amine nitrogen atom in the ester residue. Grafted polymer, non-grafted polymer and non-grafted saturated polymer obtained by electron beam irradiation to a mixture consisting of 2 to 30% by weight of α,β-unsaturated carboxylic acid ester containing one α,β-unsaturated carboxylic acid ester are uniformly dispersed. A water-dispersible resin composition which is a mixture of: 2. (a) Addition or condensation polymerization reaction between an organic compound having an alcoholic hydroxyl group or a phenolic hydroxyl group and (b) an organic compound having a group selected from the group consisting of a carboxy group, an isocyanate group, a glycidyl group, or an aldehyde group. 50-98% by weight of a saturated polymer obtained by, 2-50% by weight of an α,β-unsaturated carboxylic acid ester containing one amine nitrogen atom in the ester residue and one ethylenically unsaturated bond. A graft polymer, a non-graft polymer and a non-graft saturated polymer obtained by electron beam irradiation are uniformly dispersed in a mixture consisting of an effective amount of 48% by weight or less of a radically polymerizable monomer. A water-dispersible resin composition which is a mixture consisting of: 3. The water-dispersible resin composition according to claim 1 or 2, wherein the saturated polymer is an epoxy resin. 4. Claim 1 or 2, wherein the saturated polymer is a heat-reactive saturated polyester obtained mainly from a saturated dihydric alcohol and a saturated dibasic acid.
The resin composition for water dispersion as described in 1. 5. The water-dispersible resin composition according to claim 1 or 2, wherein the saturated polymer is a heat-reactive saturated polyurethane resin obtained mainly from a saturated dihydric alcohol and a saturated polyisocyanate. 6. The water-dispersible resin composition according to claim 1 or 2, wherein the saturated polymer is a heat-reactive phenolic resin. 7. The water-dispersible resin composition according to claim 1 or 2, wherein the saturated polymer is a condensate obtained by the reaction of polyvinyl alcohol and alkyl aldehyde. 8 Irradiation temperature is -50 to 50℃, electron beam dose rate 1
Claims 1 or 2 obtained by irradiating a total dose of 5 to 50 MR at ×10 ⁴ to 3 × 10 ⁶ rad/sec.
The resin composition for water dispersion as described in 1.