Aqueous resin dispersion, method for its production, coating material and laminate

Abstract

To provide an aqueous dispersion of a resin wherein dispersed particles are stable with fine particle sizes and whereby bleeding out is suppressed, which is thus useful as e.g. a surface treating agent for a polyolefin substrate, an adhesive or a coating material. A resin dispersion having dispersed in water a polymer (C) having a hydrophilic polymer (B) bonded to a polyolefin (A) in a ratio of (A):(B)=100:5 to 100:500 (weight ratio); a method for producing the resin dispersion; and a coating material and a laminate, employing it.

1 . An aqueous resin dispersion which has particles made of a polymer (IC) comprising a propylene polymer (IA) and particles made of at least one resin (ID) selected from the group consisting of an acrylic resin, a polyester resin, a polyurethane resin, an epoxy resin and a vinyl ester resin, respectively dispersed in water, and which satisfies the following (1) to (4):
 (1) the weight ratio of the propylene polymer (IA) to the resin (ID) is from 90:10 to 10:90,   (2) the weight ratio of the total amount of the polymer (IC) and the resin (ID) to water is from 5:95 to 60:40,   (3) the content of a surfactant is at most 10 parts by weight per 100 parts by weight of the total amount of the polymer (IC) and the resin (ID), and   (4) the 50% particle diameter of the particles made of the polymer (IC) is at most 0.5 μm and at most 0.9 time of the 50% particle diameter of the particles of the resin (ID).   
     
     
         2 . The aqueous resin dispersion according to  claim 1 , wherein the polymer (IC) is a polymer having a hydrophilic polymer (IB) bonded to the propylene polymer (IA) in a ratio of (IA):(IB)=100:5 to 100:500 (weight ratio). 
     
     
         3 . The aqueous resin dispersion according to  claim 2 , wherein the polymer (IC) is a polymer having the hydrophilic polymer (IB) bonded in an amount of from 0.01 to 5 mmol per 1 g of the propylene polymer (IA). 
     
     
         4 . The aqueous resin dispersion according to  claim 2 , wherein the polymer (IC) is a graft copolymer having a hydrophilic polymer (IB) graft-bonded to the propylene polymer (IA). 
     
     
         5 . The aqueous resin dispersion according to  claim 2 , wherein the polymer (IC) is a polymer having a carboxylic acid derivative group bonded to the propylene polymer (IA) in an amount of from 0.01 to 5 mmol/g as calculated as a group represented by —C(═O)O— and wherein the hydrophilic polymer (IB) is bonded to the carboxylic acid derivative group. 
     
     
         6 . The aqueous resin dispersion according to  claim 2 , wherein the hydrophilic polymer (IB) is a polyether resin having an amino group. 
     
     
         7 . The aqueous resin dispersion according to  claim 1 , wherein the polymer (IC) is one having a carboxylic acid derivative group bonded to the propylene polymer (IA). 
     
     
         8 . The aqueous resin dispersion according to  claim 1 , wherein the propylene polymer (IA) is a stereo-block polypropylene polymer having isotactic blocks and atactic blocks. 
     
     
         9 . The aqueous resin dispersion according to  claim 8 , wherein the propylene polymer (IA) is a stereo-block polypropylene polymer comprising isotactic blocks and atactic blocks, and when peaks derived from the carbon atom of a methyl group of a propylene unit chain portion of a head-to-tail linkage, are observed by  13 C-NMR and the chemical shift of a peak top of a peak attributable to a pentad represented by mmmm is set to be 21.8 ppm, the ratio (S 1 /S) of the area S 1  of a peak having a peak top at 21.8 ppm to the total area S of peaks appearing from 19.8 ppm to 22.1 ppm, is from 20% to 70%, and when the area of a peak (mmmr) having a peak top from 21.5 to 21.7 ppm is represented by S 2 , 4+2S 1 /S 2 >5. 
     
     
         10 . The aqueous resin dispersion according to  claim 1 , wherein the propylene polymer (IA) is a propylene-1-butene copolymer having a propylene content of from 50 mol % to 95 mol %, and the copolymer (IA) has a molecular weight distribution Mw/Mn of at most 3.0 and a melting point Tm of at most 120° C. 
     
     
         11 . The aqueous resin dispersion according to  claim 1 , wherein the propylene polymer (IA) is produced by using a metallocene catalyst. 
     
     
         12 . The aqueous resin dispersion according to  claim 1 , which further comprises a pigment (IE), wherein the weight ratio of the total amount of the polymer (IC) and the resin (ID) to the pigment (IE) is from 100:10 to 100:400. 
     
     
         13 . A coating material made of the aqueous resin dispersion as defined in  claim 1 . 
     
     
         14 . A laminate having formed on a thermoplastic resin-molded product (IF) a layer comprising a polymer (IC) comprising a propylene polymer (IA) and at least one resin (ID) selected from the group consisting of an acrylic resin, a polyester resin, a polyurethane resin, an epoxy resin and a vinyl ester resin in a weight ratio of (IA):(ID)=90:10 to 10:90 and having a surfactant content of at most 10 parts by weight per 100 parts by weight of the total amount of the polymer (IC) and the resin (ID). 
     
     
         15 . A laminate having a resin layer formed by applying and heating the aqueous resin dispersion as defined in  claim 1 , on a thermoplastic resin-molded product (IF).