CN-122029207-A - Aqueous polyolefin resin dispersion, process for producing the same, and coating film

Abstract

The purpose of the present invention is to provide an aqueous polyolefin resin dispersion which has excellent stability in a high-temperature environment and can form a coating film having excellent surface smoothness, and which can form a coating film having high transparency even when the coating film is formed at a low temperature. The aqueous polyolefin resin dispersion of the present invention comprises acid-modified polyolefin resin particles and an aqueous medium, wherein the acid-modified polyolefin resin constituting the acid-modified polyolefin resin particles comprises 50 mass% or more of structural units derived from propylene in 100 mass% of the total structural units, and the median particle diameter (D50) of the acid-modified polyolefin resin particles in the aqueous dispersion is 0.03 [ mu ] m to 1.00 [ mu ] m, the 90% particle diameter (D90) is 2.00 times or less of the median particle diameter, and the 95% particle diameter (D95) is 2.20 times or less of the median particle diameter in a volume-based cumulative particle size distribution measured by a dynamic light scattering method.

Inventors

• YOSHINO TAKAMASA
• YAMADA MUNENORI
• YAMAMOTO KAZUFUMI

Assignees

• 尤尼吉可株式会社

Dates

Publication Date

20260512

Application Date

20241025

Priority Date

20231031

Claims (6)

1. 1. An aqueous polyolefin resin dispersion comprising acid-modified polyolefin resin particles and an aqueous medium, The acid-modified polyolefin resin constituting the acid-modified polyolefin resin particles contains 50 mass% or more of structural units derived from propylene in 100 mass% of the total structural units, In the volume-based cumulative particle size distribution obtained by measurement by a dynamic light scattering method, the acid-modified polyolefin resin particles in the aqueous dispersion have a median particle diameter D50 of 0.03 μm to 1.00 μm, a 90% particle diameter D90 of 2.00 times or less the median particle diameter, and a 95% particle diameter D95 of 2.20 times or less the median particle diameter.
2. 2. The aqueous polyolefin resin dispersion according to claim 1, wherein the total frequency of acid-modified polyolefin resin particles having a particle diameter of 2 times or more of the median particle diameter in the acid-modified polyolefin resin particles in the aqueous dispersion is 10.0% or less in the volume-based cumulative particle size distribution measured by a dynamic light scattering method.
3. 3. The aqueous polyolefin resin dispersion according to claim 1, wherein the acid-modified polyolefin resin comprises structural units derived from at least one olefin selected from the group consisting of ethylene, isobutylene, 1-butene and 2-butene.
4. 4. The aqueous polyolefin resin dispersion according to claim 1, wherein the acid-modified polyolefin resin contains 0.1 to 10 mass% of structural units derived from an unsaturated carboxylic acid and/or structural units derived from an unsaturated carboxylic acid anhydride in 100 mass% of the total structural units.
5. 5. The method for producing an aqueous polyolefin resin dispersion according to any one of claims 1 to 4, comprising the steps of: A composition containing at least the acid-modified polyolefin resin and an aqueous medium is stirred using a Maxblend blade as a stirring blade at a stirring rotation speed of 350rpm or more.
6. 6. A coating film obtained from the aqueous polyolefin resin dispersion according to any one of claims 1 to 4.

Description

Aqueous polyolefin resin dispersion, process for producing the same, and coating film Technical Field The present invention relates to an aqueous polyolefin resin dispersion, a method for producing the same, and a coating film. Background Polyolefin resins, particularly propylene resins, are used in a large amount mainly in automobiles, electric fields, packaging, and daily sundries because of their excellent electric characteristics, mechanical characteristics, chemical characteristics, and the like. Particularly, in the use of adhesives and coating agents, an aqueous polyolefin resin dispersion is often used (for example, refer to patent document 1). Prior art literature Patent literature Patent document 1 International publication No. 2004/104090 Disclosure of Invention Technical problem to be solved by the invention In order to use the aqueous polyolefin resin dispersion for a wider range of applications, stability of the aqueous polyolefin resin dispersion in a high-temperature environment and surface smoothness of a coating film formed from the aqueous polyolefin resin dispersion are required. In particular, in order to use the aqueous polyolefin resin dispersion for adhesion of a substrate susceptible to heat, it is required that a coating film of the aqueous polyolefin resin dispersion can be formed at a low temperature. However, a coating film formed at a low temperature using a conventional aqueous polyolefin resin dispersion has a problem that it is difficult to obtain sufficient transparency. The purpose of the present invention is to provide an aqueous polyolefin resin dispersion which has excellent stability in a high-temperature environment and can form a coating film having excellent surface smoothness, and which can form a coating film having high transparency even when the coating film is formed at a low temperature. Technical scheme for solving technical problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that an aqueous polyolefin resin dispersion having excellent stability in a high-temperature environment, capable of forming a coating film having excellent surface smoothness, and capable of forming a coating film having high transparency even in the case of forming a coating film at a low temperature can be obtained by using an acid-modified polyolefin resin having 50 mass% or more of structural units derived from propylene in 100 mass% of all structural units, and having a specific particle size distribution in the aqueous dispersion. Further, the present inventors have found that by stirring a composition containing the acid-modified polyolefin resin and an aqueous medium under a stirring speed of 350rpm or more using a maxbend blade as a stirring blade, acid-modified polyolefin resin particles having a specific particle size distribution can be obtained. The present invention has been completed based on the above findings and further repeated studies. That is, the present invention provides the following disclosed embodiments. Item 1. An aqueous polyolefin resin dispersion comprising acid-modified polyolefin resin particles and an aqueous medium, The acid-modified polyolefin resin constituting the acid-modified polyolefin resin particles contains 50 mass% or more of structural units derived from propylene in 100 mass% of the total structural units, In the volume-based cumulative particle size distribution obtained by measurement by a dynamic light scattering method, the acid-modified polyolefin resin particles in the aqueous dispersion have a median particle diameter (D50) of 0.03 μm to 1.00 μm, a 90% particle diameter (D90) of 2.00 times or less the median particle diameter, and a 95% particle diameter (D95) of 2.20 times or less the median particle diameter. The polyolefin resin aqueous dispersion according to item 1, wherein the total frequency of acid-modified polyolefin resin particles having a particle diameter of 2 times or more the median particle diameter in the acid-modified polyolefin resin particles in the aqueous dispersion is 10.0% or less in the volume-based cumulative particle size distribution measured by the dynamic light scattering method. The aqueous polyolefin resin dispersion according to item 1 or 2, wherein the acid-modified polyolefin resin contains a structural unit derived from at least one olefin selected from the group consisting of ethylene, isobutylene, 1-butene and 2-butene. The aqueous polyolefin resin dispersion according to any one of items 1 to 3, wherein the acid-modified polyolefin resin contains 0.1 to 10 mass% of structural units derived from an unsaturated carboxylic acid and/or structural units derived from an unsaturated carboxylic acid anhydride, based on 100 mass% of the total structural units. The method for producing an aqueous polyolefin resin dispersion according to any one of items 1 to 4, comprising the step of stirring a composition containing at least the ac