AQUEOUS RESIN DISPERSION

Abstract

The invention provides an aqueous resin dispersion which can form a coating film excellent in adhesion to a polypropylene base material, and water resistance, and has excellent particle stability. Specifically, it provides an aqueous resin dispersion in which an olefin polymer (A), and a polymer (C) containing a constituent unit derived from a radically polymerizable monomer (B) represented by the following general formula (1) are dispersed in an aqueous medium. (In the general formula (1), R is a hydrogen atom or a methyl group, and X is a straight chain or branched alkylene group having 3 to 5 carbon atoms; and n is an integer of 1 to 20.)

Claims

1. An aqueous resin dispersion (D) in which an olefin polymer (A), and a polymer (C) containing a constituent unit derived from a radically polymerizable monomer (B) represented by the following general formula (1) are dispersed in an aqueous medium, ##STR00003## wherein R is a hydrogen atom or a methyl group, and X is a straight chain or branched alkylene group having 3 to 5 carbon atoms; and n is an integer of 1 to 20.

2. The aqueous resin dispersion according to claim 1, wherein n in the general formula (1) is 1.

3. The aqueous resin dispersion according to claim 1, wherein particles containing the olefin polymer (A) and the polymer (C) are dispersed in an aqueous medium.

4. The aqueous resin dispersion according to claim 1, wherein a proportion of the constituent unit derived from a radically polymerizable monomer (B) contained in the polymer (C) is from 0.01 to 50 mass % of the polymer (C).

5. The aqueous resin dispersion according to claim 1, wherein the olefin polymer (A) does not contain a chlorine atom.

6. An aqueous olefinic resin dispersion (ID) in which an olefin polymer (A) and a polymer (IC) containing a constituent unit derived from a radically polymerizable monomer (IB) having an acidic group are dispersed in an aqueous medium, wherein an acid value of the polymer (IC) is from 1 to 9 mg KOH/g, and wherein contents of the olefin polymer (A) and the polymer (IC) in the aqueous olefinic resin dispersion (ID) in terms of mass ratio are: Olefin polymer (A): Polymer (IC)=10:90 to 90:10.

7. The aqueous olefinic resin dispersion according to claim 6, further comprising a surfactant (E), wherein a content of the surfactant (E) is 3 parts by mass or less with respect to 100 parts by mass of the polymer (IC).

8. The aqueous olefinic resin dispersion according to claim 6, wherein the radically polymerizable monomer (1B) having an acidic group is acrylic acid or methacrylic acid.

9. The aqueous olefinic resin dispersion according to claim 6, wherein particles containing the olefin polymer (A) and the polymer (IC) are dispersed in an aqueous medium.

Description

EXAMPLES

[0113] The present invention will be described below in more detail by way of Examples and Comparative Examples. Parts and % in Examples represent parts by mass and mass %, respectively. Each evaluation on aqueous resin dispersions was carried out by the following method.

<Evaluation of Aqueous Resin Dispersion>

[0114] 1. Initial Adhesion

[0115] (Preparation of Coating Material)

[0116] To the solid component of an aqueous resin dispersion, 60 parts of diethylene glycol monobutyl ether as a film forming aid, and 3 parts each of TEGO? WET KL-245 (trade name, produced by Evonik Industries AG) as a base material wetting agent, and BYK-345 (trade name, produced by BYK Japan KK) were added, and the mixture was stirred using a homogenizer (trade name: POLYTRON PT-3100, produced by Central Scientific Commerce, Inc.) at 700 rpm for 5 min. Left standing at room temperature for 1 day, then the mixture was filtrated with a 300 mesh screen to obtain a water-based coating material.

[0117] Next, the surface of a 3 mm-thick substrate molded from a polypropylene resin (trade name: TSOP-6, produced by Japan Polypropylene Corp.) was cleaned with isopropyl alcohol. The obtained water-based coating material was sprayed on the substrate such that the dry film thickness became 20 ?m, allowed to set at room temperature for 10 min, and then dried in a safe vent dryer in an atmosphere of 80? C. for 30 min to form a coating film. This was left standing at room temperature for 1 day to obtain a test piece.

[0118] Then, on the coating film side of the test piece, 11 cross-cuts deep enough to reach the base material were made at intervals of 1 mm in both length and width directions to make 100 cross-cut squares. Then, after sticking a cellophane adhesive tape over the cross-cut squares, the adhesive tape was peeled abruptly, and the resultant condition of the coating film was observed, and the number of squares where the coating film was detached (detached squares) was counted. The initial adhesion was evaluated based on the following rating criteria.

[0119] ? (Excellent): 0 to 9 detached squares out of 100 squares

[0120] ? (Average): 10 to 19 detached squares out of 100 squares

[0121] ? (Bad): 20 to 100 detached squares out of 100 squares

[0122] 2. Water Resistance (Mass Decrement)

[0123] The surface of a glass substrate was cleaned with isopropyl alcohol. The obtained aqueous resin dispersion was coated on the glass substrate such that the dry film thickness became 100 ?m. The plate was dried in a safe vent dryer in an atmosphere of 90? C. for 30 min to form a coating film. This was left standing at room temperature for 1 day and the coating film was peeled from the glass substrate to obtain a test piece.

[0124] The prepared test piece was cut into 10 mm?10 mm and placed in a sample bottle such that the mass (initial mass: W1) became 1 g. After adding 100 mL of water to the sample bottle, the bottle was stored at 40? C. for 10 days in a thermostat. After the storage, the test piece was taken out and the mass (mass after 10 days at 40? C.: W2) was measured, and the mass decrement was calculated by the following calculation formula.

Mass decrement (mass %)=[(W1(g)?W2(g))/W1(g)]?100

[0125] ? (Excellent): Mass decrement is 2.0 mass % or less

[0126] ? (Average): Mass decrement is 2.1 mass % or more and 3.0 mass % or less

[0127] ? (Bad): Mass decrement is 3.1 mass % or more

[0128] 3. Solvent Stability

[0129] To an aqueous resin dispersion of the present invention, 20 mass % of 2-ethylhexanol with respect to the solid component of the aqueous resin dispersion was added, and the mixture was stirred using a homogenizer (trade name: POLYTRON PT-3100, produced by Central Scientific Commerce, Inc.) for 5 min. With respect to the obtained aqueous resin dispersion, presence or absence of aggregates was examined with a grind gauge. The solvent stability was evaluated according to the following rating criteria. This solvent stability indicates the dispersion stability of an aqueous resin dispersion.

[0130] ? (Excellent): No aggregate.

[0131] ? (Average): Aggregates are formed, but solidification did not occur.

[0132] ? (Bad): Solidification occurred.

[0133] 4. Observation of Particle Structure of Aqueous Resin Dispersion

[0134] An aqueous resin dispersion was added to an agarose gel dissolved in a hot water bath, and the mixture was cooled to solidify, then cut into a size of about 1 mm cube, and the impregnated water was replaced with an epoxy resin. Subsequently, the mixture was polymerized and cured in a gelatin capsule, and an ultrathin section having a thickness of 70 nm was prepared with an ultramicrotome. Observation was performed on the obtained ultrathin section using a transmission electron microscope (trade name: H-7600, produced by Hitachi High-Technologies Corp.) at an acceleration voltage of 80 kV.

<Production of Aqueous Resin Dispersion (D)>

Example 1

[0135] Into a flask equipped with a stirrer, a reflux condenser, and a temperature controller were charged 336.7 parts of APTOLOK? BW-5683 (produced by Mitsubishi Chemical Corporation: solid component 29.6%) as an olefin polymer (A), 119.6 parts of deionized water, and 8.0 parts of ADEKA REASOAP SR-1025 (trade name, produced by Adeka Corporation: solid component 25%) as a surfactant, and the temperature thereof was raised to 30? C.

[0136] Next, 5.2 parts of 2-hydroxypropyl methacrylate as a radically polymerizable monomer (B), and 94.8 parts of butyl acrylate as another vinyl type monomer were added, and the temperature was raised to 60? C. and held for 1 hour. Further, 0.02 parts of PERBUTYL? H69 (trade name, produced by NOF Corporation, solid component 69%) as an initiator, 0.0002 parts of ferrous sulfate as a reducing agent, 0.00027 parts of ethylenediaminetetraacetic acid (EDTA), 0.08 parts of sodium isoascorbate monohydrate, and 1 part of deionized water were added, and polymerization was initiated.

[0137] After detecting an exothermic peak of polymerization, 0.03 parts of PERBUTYL? H69, and 10.0 parts of deionized water were added dropwise over 15 min. After completion of drop-wise addition, ripening was carried out at 60? C. for 30 min to obtain an aqueous resin dispersion (D). With respect to the obtained aqueous resin dispersion, the initial adhesion, water resistance, and solvent stability were evaluated. The evaluation results are shown in Table 1. A11the expressions of parts by mass in Table 1 refer to the parts by mass of a solid component.

Example 2

[0138] Into a flask equipped with a stirrer, a reflux condenser, and a temperature controller were charged 336.7 parts of APTOLOK? BW-5683 (produced by Mitsubishi Chemical Corporation: solid component 29.6%) as an olefin polymer (A), 119.6 parts of deionized water, and 8.0 parts of ADEKA REASOAP SR-1025 (trade name, produced by Adeka Corporation: solid component 25%) as a surfactant, and the temperature thereof was raised to 30? C.

[0139] Next, 10.4 parts of 2-hydroxypropyl methacrylate as a radically polymerizable monomer (B), and 89.6 parts of butyl acrylate as another vinyl type monomer were added, and the temperature was raised to 60? C. and held for 1 hour. Further, 0.02 parts of PERBUTYL? H69 (trade name, produced by NOF Corporation, solid component 69%) as an initiator, 0.0002 parts of ferrous sulfate as a reducing agent, 0.00027 parts of ethylenediaminetetraacetic acid (EDTA), 0.08 parts of sodium isoascorbate monohydrate, and 1 part of deionized water were added, and polymerization was initiated.

[0140] After detecting an exothermic peak of polymerization, 0.03 parts of PERBUTYL? H69, and 10.0 parts of deionized water were added dropwise over 15 min. After completion of drop-wise addition, ripening was carried out at 60? C. for 30 min to obtain an aqueous resin dispersion (D). With respect to the obtained aqueous resin dispersion, the initial adhesion, water resistance, and solvent stability were evaluated. The evaluation results are shown in Table 1.

[0141] When the particle structure of the obtained aqueous resin dispersion (D) was analyzed using a certain transmission electron microscope, a particle containing the olefin polymer (A) and the polymer (C) was observed.

Examples 3 to 6, and Comparative Examples 1 and 2

[0142] An aqueous resin dispersion was obtained in the same manner as in Example 1 except that the radically polymerizable monomer (B), other vinyl type monomer, and surfactant as well as the contents thereof were changed as set forth in Table 1. With respect to the obtained aqueous resin dispersion, the initial adhesion, water resistance, and solvent stability were evaluated. The evaluation results are shown in Table 1.

TABLE-US-00001 TABLE 1 Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 1 Example 2 Olefin polymer APTOLOK 100 100 100 100 100 100 100 100 (A) parts by mass BW-5683 Radically polymerizable HPMA 5.2 10.4 20.8 monomer 4HBA 0.6 10.4 20.8 (B) parts by mass Vinyl type monomer HEMA 9.7 parts by mass HEA 8.2 BA 94.8 89.6 79.2 99.4 89.6 79.2 90.3 91.8 Surfactant parts by mass ADEKA REASOAP 2 2 2 2 2 2 2 2 SR-1025 Hydroxyl value of mgKOH/g 20 40 80 2.2 40 80 40 40 polymer (C) Evaluation of aqueous resin Initial adhesion ? ? ? ? ? ? X X dispersion (D) (Detached squares/ 0/100 0/100 0/100 0/100 0/100 0/100 20/100 20/100 Total squares) Water resistance test ? ? ? ? ? ? ? X (Mass decrement) 2.0% 1.8% 2.0% 2.0% 1.2% 1.8% 1.8% 3.2% Solvent stability ? ? ? ? ? ? ? ?

[0143] Abbreviations in Table 1 represent respectively the following compounds.

[0144] HPMA: 2-Hydroxypropyl methacrylate

[0145] 4-Hydroxybutyl acrylate

[0146] HEMA: 2-Hydroxyethyl methacrylate

[0147] HEA: 2-Hydroxyethyl acrylate

[0148] BA: Butyl acrylate

[0149] As shown in Table 1, each of the aqueous resin dispersions according to Examples 1 to 6 of the present invention includes an olefin polymer (A), and a polymer (C) containing a constituent unit derived from a radically polymerizable monomer (B) wherein R in the general formula (1) is a hydrogen atom or a methyl group, X is a straight chain or branched alkylene group having 3 or 4 carbon atoms, and n is 1. Further, since in each of the aqueous resin dispersions, particles containing both the olefin polymer (A) and the polymer (C) are dispersed, the obtained coating film was superior in initial adhesion and water resistance.

[0150] On the other hand, each of the aqueous resin dispersions according to Comparative Examples 1 and 2 includes as a radically polymerizable monomer (B) a vinyl type monomer in which X in the general formula (1) is a straight chain alkyl group having 2 carbon atoms, and therefore the obtained coating film was inferior in initial adhesion.

<Production of Aqueous Olefinic Resin Dispersion (ID)>

Example 7

[0151] Into a flask equipped with a stirrer, a reflux condenser, and a temperature controller were charged 333.3 parts of APTOLOK BW-5635 (trade name, produced by Mitsubishi Chemical Corporation: solid component 30.0%) as an olefin polymer (A), 119.6 parts of deionized water, and 8.0 parts of ADEKA REASOAP SR-1025 (trade name, produced by Adeka Corporation: solid component 25%) as a surfactant, and the temperature thereof was held at 30? C.

[0152] Next, 0.5 parts of methacrylic acid as a radically polymerizable monomer (IB), and 10.4 parts of 4-hydroxybutyl acrylate, 44.6 parts of isobutyl methacrylate, and 44.6 parts of butyl acrylate as vinyl type monomers were added, and the temperature was held at 50? C. for 1 hour.

[0153] Further, 0.02 parts of PERBUTYL? H69 (trade name, produced by NOF Corporation) as an initiator, 1.0 parts of deionized water, 0.002 parts of iron sulfate heptahydrate, 0.00027 parts of ethylenediaminetetraacetic acid, and 0.08 parts of sodium erythorbate were added, and polymerization was initiated.

[0154] After detecting an exothermic peak of polymerization, 0.03 parts of PERBUTYL H69, and 10.0 parts of deionized water were added dropwise over 15 min. After completion of drop-wise addition, ripening was carried out at 60? C. for 30 min, and then the system were cooled down to 30? C. Thereafter, 0.5 parts by mass of dimethylethanolamine was added, and the system was stirred for 30 min to be neutralized. In this way, an aqueous resin dispersion (ID) having an average particle diameter of 150 nm was obtained. With respect to the obtained aqueous resin dispersion, the initial adhesion, and solvent stability were evaluated. The evaluation results are shown in Table 2. All the expressions of parts by mass in Table 2 refer to the parts by mass of a solid component.

Examples 8 to 14

[0155] An aqueous resin dispersion was obtained in the same manner as in Example 7 except that the contents of the radically polymerizable monomer (IB), vinyl type monomer, surfactant and amine with respect to olefin polymer (A) was changed as set forth in Table 2. With respect to the obtained aqueous resin dispersion, each evaluation was carried out in the same manner as in Example 7. The evaluation results are shown in Table 2.

[0156] Abbreviations in Table 2 represent respectively the following compounds.

[0157] MAA: Methacrylic acid

[0158] AA: Acrylic acid

[0159] iBMA: Isobutyl methacrylate

[0160] DMEA: Dimethylethanolamine

TABLE-US-00002 TABLE 2 Example Example Example Example Example 7 Example 8 Example 9 Example 10 11 12 13 14 Olefin polymer APTOLOK 100 100 100 100 100 100 100 100 (A) parts by mass BW-5635 Radically polymerizable MAA 0.5 1 0.5 0.75 1 0.1 monomer (IB) parts by mass AA 0.8 Vinyl type monomer 4HBA 10.4 10.4 10.4 10.4 10.4 10.4 10.4 10.4 parts by mass iBMA 44.6 44.1 65 44.8 44.8 BA 44.6 44.6 24 88.8 88.6 88.8 44.8 44.8 Surfactant parts by mass ADEKA REASOAP 2 2 2 2 2 2 2 2 SR-1025 Amine parts by mass DMEA 0.5 1.0 0.5 0.78 1.0 1.0 0.1 Acid value of polymer (IC) mgKOH/g 3.3 6.5 3.3 4.9 6.5 6.2 0 0.7 Evaluation of aqueous resin Initial adhesion ? ? ? ? ? ? ? ? dispersion (ID) (Detached squares/ 0/100 0/100 0/100 0/100 0/100 0/100 0/100 0/100 Total squares) Solvent stability ? ? ? ? ? ? X X

[0161] As shown in Table 2, with respect to any of the aqueous resin dispersions according to Examples 7 to 12 of the present invention, the acid value of the polymer (IC) containing a constituent unit derived from a radically polymerizable monomer (IB) was from 1 to 9 mg KOH/g, and therefore it was excellent in initial adhesion and solvent stability. However, with respect to any of the aqueous resin dispersions according to Examples 13 and 14, the acid value of the polymer (IC) containing a constituent unit derived from a radically polymerizable monomer (IB) was low, and therefore it was inferior to the aqueous resin dispersions according to Examples 7 to 12 in solvent stability.