WO2024001004A1

WO2024001004A1 - Waterborne dipping coating for measuring tape and preparation method therefor

Info

Publication number: WO2024001004A1
Application number: PCT/CN2022/133261
Authority: WO
Inventors: 安自杰; 闫树德; 王亚轩; 郑齐; 田军; 黄星雨
Original assignee: 广东衡光新材料科技有限公司
Priority date: 2022-06-29
Filing date: 2022-11-21
Publication date: 2024-01-04
Also published as: CN114989682A

Abstract

A waterborne dipping coating for a measuring tape, relating to the field of waterborne coatings, and comprising the following components in parts by weight: 45-55 parts of a waterborne hydroxy acrylic acid secondary dispersion, 1-2 parts of a waterborne epoxy resin, 6-10 parts of a partially methylated amino resin, 0.1-0.5 parts of a pH regulator, 2-6 parts of a coalescing agent, 0.5-1 parts of a dispersing agent, 0.1-0.3 parts of a wetting agent, 0.1-0.3 parts of a defoaming agent, 1-2 parts of a waterborne blocked isocyanate curing agent, 10-20 parts of water, 20-25 parts of titanium dioxide, 0.5-1 parts of an anti-settling and anti-sagging auxiliary agent, and 0.2-0.5 parts of a thickening agent. The pH regulator, the dispersing agent, the wetting agent, the defoaming agent, the titanium dioxide, and the anti-settling and anti-sagging auxiliary agent are stirred to obtain early-stage water slurry, and then the waterborne hydroxyl acrylic acid secondary dispersion, the partially methylated amino resin, the waterborne epoxy resin, the waterborne blocked isocyanate curing agent, the early-stage water slurry, the coalescing agent, and the thickening agent are uniformly stirred to obtain the waterborne dipping coating for a measuring tape. The waterborne dipping coating for a measuring tape prepared in the present invention has a low VOC content, and has properties such as high adhesion, high hardness, and excellent salt spray resistance.

Description

A kind of dip coating for water-based tape measure and preparation method thereof

Technical field

The invention belongs to the field of water-based coatings, and specifically relates to a dip-coating coating for water-based tape measures and a preparation method thereof.

Background technique

Tape measure coating is a special coating, which is limited to the coating of steel measuring tapes. Due to the characteristics of the steel tape measure and the requirements of the coating process, the performance requirements for the tape measure include: high adhesion, impact resistance, flexibility, hardness and anti-corrosion properties of the paint film. The coating method generally adopts the dip coating construction method, which is convenient And high efficiency. The water-based tape measure coatings currently known are basically water-soluble acrylic coatings. Water-soluble acrylic resins contain about 30% solvents. Although there are certain technical improvements compared to solvent-based coatings, they are fundamentally organic solvents. The content cannot meet the latest environmental protection requirements.

Contents of the invention

In order to solve the above-mentioned problems existing in the prior art, the present invention provides a dip coating for water-based tape measures and a preparation method thereof. The water-based dip coating for tape measures of the present invention selects water-based hydroxypropylene secondary dispersion as the main film-forming substance, and the various components in the entire formula cooperate with each other. The obtained water-based dip coating for tape measures combines solvent-based and water-soluble Compared with non-toxic coatings, the VOC content is lower, and the coating of the present invention has excellent film-forming properties, high adhesion and hardness, excellent salt spray resistance, excellent sag resistance and other properties.

The specific technical solutions adopted by the present invention are:

A water-based dip coating for tape measures, including the following components by weight: 45-55 parts of water-based hydroxyacrylic acid secondary dispersion, 1-2 parts of water-based epoxy resin, 6-10 parts of partially methyl etherified amino resin, 0.1-0.5 parts of pH regulator, 2-6 parts of film-forming aid, 0.5-1 part of dispersant, 0.1-0.3 parts of wetting agent, 0.1-0.3 parts of defoaming agent, 1-2 parts of water-based blocked isocyanate curing agent , 10-20 parts of water, 20-25 parts of titanium dioxide, 0.5-1 part of anti-settling and anti-sag additives, 0.2-0.5 parts of thickener.

As a further technical solution, a water-based dip coating for tape measure includes the following components by weight: 50 parts of water-based hydroxyacrylic secondary dispersion, 1.5 parts of water-based epoxy resin, 8 parts of partially methyl etherified amino resin, 0.3 parts of pH regulator, 5 parts of film-forming additive, 0.8 parts of dispersant, 0.2 parts of wetting agent, 0.2 parts of defoaming agent, 1.5 parts of water-based blocked isocyanate curing agent, 14 parts of water, 22 parts of titanium dioxide, anti-sedimentation 0.8 parts of anti-sag additive and 0.4 parts of thickening agent.

As a further technical solution, the pH adjuster is dimethylethanolamine or 2-amino-2-methyl-1-propanol.

As a further technical solution, the film-forming assistant is one or more of dipropylene glycol methyl ether, dipropylene glycol butyl ether, propylene glycol butyl ether, diethylene glycol butyl ether, and isobutanol.

As a further technical solution, the dispersant is a polycarboxylate sodium salt dispersant or an ammonium salt dispersant.

As a further technical solution, the wetting agent is a water-based silicone wetting agent, the defoaming agent is a polyethersiloxane copolymer defoaming agent, and the anti-settling and anti-sag additive is a gas phase method II Silicon oxide, the thickener is an associative polyurethane thickener.

A method for preparing dip coating for water-based tape measures, including the following steps:

A. According to the proportion of water-based tape measure and dip coating, weigh each component and set aside;

B. Add water to the reactor, and at stirring speed A, add pH regulator, dispersant, wetting agent, defoaming agent, titanium dioxide, anti-settling and anti-sag additives to the reactor in sequence, and stir evenly. Finally, mixture A is obtained, and the early stage water slurry is obtained after grinding mixture A;

C. Add the water-based hydroxyacrylic acid secondary dispersion into the reactor. At stirring speed B, add part of the methyl etherified amino resin, water-based epoxy resin, water-based blocked isocyanate curing agent, and preliminary water slurry to the reactor. , film-forming aids and thickeners, and then stir evenly to obtain a water-based dip coating for tape measures.

As a further technical solution, the stirring speed A described in step B is 500-800rmp, and the pH regulator, dispersant, wetting agent, defoaming agent, titanium dioxide, anti-settling and anti-sag are added to the reactor in sequence. The additives are PH adjuster, dispersant, wetting agent, defoaming agent, titanium dioxide, and anti-settling and anti-sag additives that are added to the reactor every 3-8 minutes.

As a further technical solution, the stirring speed B in step C is 500-800rmp, and the partial methyl etherified amino resin, water-based epoxy resin, water-based blocked isocyanate curing agent, preliminary water slurry, and Film-forming aids and thickeners are added to the reactor in sequence every 8-15 minutes, including part of the methyl etherified amino resin, water-based epoxy resin, water-based blocked isocyanate curing agent, early water slurry, film-forming aids, and thickening agents. agent.

The beneficial effects of the present invention are:

1. In the present invention, through the optimized design of the water-based dipping coating ratio for tape measure and the preparation method, water-based hydroxypropylene secondary dispersion is selected as the main film-forming material. Each component in the entire formula cooperates with each other to play a mutual role. With synergistic and reinforcing effects, the prepared water-based dip coating for tape measures has lower VOC content than solvent-based and water-soluble coatings, and the coating of the present invention has excellent film-forming properties, high adhesion and hardness, and excellent Excellent salt spray resistance, excellent sag resistance and other properties.

2. In the present invention, the water-based hydroxypropylene secondary dispersion is the main film-forming substance and partially methyl etherified amino resin is used as a cross-linking agent to perform a curing cross-linking reaction. However, the partially methyl etherified amino resin is too active due to its hydroxymethyl group. , is easy to self-crosslink, and has less cross-linking with the resin hydroxyl group, resulting in relatively poor performance. Therefore, a blocked isocyanate curing agent is added. The blocked isocyanate curing agent will release the isocyanate group and the hydroxymethyl group on the partially methyl etherified amino resin. The reaction forms a cross-linked structure and increases the cross-link density, which can significantly improve the salt spray resistance, water resistance, chemical resistance and other properties of the water-based resin. In addition, epoxy resin, water-based hydroxypropylene secondary dispersion, and partial methane are added. A complex chemical reaction occurs between etherified amino resin, blocked isocyanate curing agent and epoxy resin, which play a synergistic and synergistic role. As an additive, epoxy resin creates a cross-linked structure with other components. Intertwined together, the overall structure is more stable, so that the paint can maintain good gloss and color retention when baked, and has excellent water resistance, salt spray resistance, acid and alkali resistance.

3. Each component in the present invention is added in batches at different nodes, so that the reaction at each stage is fully carried out. By controlling the proportion, adding method, and stirring method of each component, the water-based tape measure prepared can be dipped The coating has the characteristics of high strength and strong adhesion.

4. The partially methyl etherified amino resin selected in the present invention is a partially methyl etherified melamine resin. This type of amino resin has less free hydroxymethyl groups, a high degree of methyl etherification, a low molecular weight, and a certain amount of imino groups retained in the molecule. Soluble in water, it is suitable for use as a cross-linking agent in water-based coatings. It undergoes a cross-linking reaction during curing and can also undergo a self-polycondensation reaction, so a coating film with excellent performance can be obtained.

Detailed ways

The water-based hydroxyacrylic acid secondary dispersion in the present invention is XG3801 produced by Hengshui Xinguang New Material Technology Co., Ltd., the partially methyl etherified amino resin is CYMEL327 produced by Cyte Chemical Shanghai Co., Ltd., and the polycarboxylic acid sodium salt dispersant is Winn TEGO755W produced by Chuang Specialty Chemicals (Shanghai) Co., Ltd., the ammonium salt dispersant is BYK760 produced by BYK Company of Germany, the wetting agent is TEGO4100 produced by Evonik Specialty Chemicals (Shanghai) Co., Ltd., and the defoaming agent is Evonik Specialty Chemicals (Shanghai) TEGO902W produced by ) Co., Ltd. uses deionized water; other raw materials used can be purchased from the market unless otherwise specified.

1. Specific embodiments

Example 1

A. According to the following formula of dip coating for water-based tape measure, weigh each component for later use: 50 parts of water-based hydroxyacrylic secondary dispersion, 1.5 parts of water-based epoxy resin, 8 parts of partially methyl etherified amino resin, and 0.3 pH regulator 5 parts of film-forming aid, 0.8 parts of dispersant, 0.2 parts of wetting agent, 0.2 parts of defoaming agent, 1.5 parts of water-based blocked isocyanate curing agent, 14 parts of deionized water, 22 parts of titanium dioxide, anti-settling and anti-flow 0.8 parts of hanging additive, 0.4 parts of thickening agent;

The film-forming assistant is composed of 60% diethylene glycol butyl ether and 40% isobutanol based on weight percentage, the pH regulator is dimethylethanolamine, and the dispersant is polycarboxylic acid sodium salt dispersant;

B. Add deionized water to the reactor, and at a stirring speed of 600 rpm, add pH adjuster, dispersant, wetting agent, defoaming agent, titanium dioxide, anti-settling and anti-sag to the reactor every 5 minutes. Add additives, stir evenly to obtain mixture A, grind mixture A to a fineness of 10 μm to obtain early stage water slurry;

C. Add the water-based hydroxyacrylic acid secondary dispersion into the reactor, and at a stirring speed of 600 rpm, add part of the methyl etherified amino resin, water-based epoxy resin, water-based blocked isocyanate curing agent, and Preliminary water slurry, film-forming aids, and thickeners are then stirred at a stirring speed of 900 rpm for 30 minutes until the materials are uniform, and a water-based dip coating for tape measures is obtained.

Example 2

A. According to the following formula of dip coating for water-based tape measure, weigh each component for later use: 45 parts of water-based hydroxyacrylic acid secondary dispersion, 1 part of water-based epoxy resin, 6 parts of partially methyl etherified amino resin, 0.3 pH regulator 4 parts of film-forming aid, 1 part of dispersant, 0.1 part of wetting agent, 0.1 part of defoaming agent, 2 parts of water-based blocked isocyanate curing agent, 20 parts of deionized water, 25 parts of titanium dioxide, anti-settling and anti-flow 1 part of hanging additive, 0.5 part of thickener;

The film-forming aid is calculated in weight percentage, consisting of 50% dipropylene glycol methyl ether and 50% isobutanol, the pH regulator is dimethylethanolamine, and the dispersant is ammonium salt dispersant;

B. Add deionized water to the reactor, and at a stirring speed of 500 rpm, add pH adjuster, dispersant, wetting agent, defoaming agent, titanium dioxide, anti-settling and anti-sag to the reactor every 8 minutes. Add additives, stir evenly to obtain mixture A, grind mixture A to a fineness of 10 μm to obtain early stage water slurry;

C. Add the water-based hydroxyacrylic acid secondary dispersion into the reactor, and at a stirring speed of 500 rpm, add part of the methyl etherified amino resin, water-based epoxy resin, water-based blocked isocyanate curing agent, and Preliminary water slurry, film-forming aids, and thickeners are then stirred at a stirring speed of 500 rpm for 35 minutes until the materials are uniform, and a water-based dip coating for tape measures is obtained.

Example 3

A. According to the following formula of dip coating for water-based tape measure, weigh each component for later use: 55 parts of water-based hydroxyacrylic acid secondary dispersion, 2 parts of water-based epoxy resin, 10 parts of partially methyl etherified amino resin, 0.5 pH regulator parts, 6 parts of film-forming additives, 0.5 parts of dispersant, 0.3 parts of wetting agent, 0.3 parts of defoaming agent, 1 part of water-based blocked isocyanate curing agent, 10 parts of deionized water, 20 parts of titanium dioxide, anti-settling and anti-flow 0.5 parts of hanging additive, 0.2 parts of thickening agent;

The film-forming additive is calculated in weight percentage, consisting of 40% dipropylene glycol methyl ether, 30% diethylene glycol butyl ether and 30% isobutanol, and the pH regulator is 2-amino-2-methyl-1-propane Alcohol, the dispersant is polycarboxylate sodium salt dispersant;

B. Add deionized water to the reactor, and at a stirring speed of 800rmp, add pH adjuster, dispersant, wetting agent, defoaming agent, titanium dioxide, anti-settling and anti-sag to the reactor every 3 minutes. Add additives, stir evenly to obtain mixture A, grind mixture A to a fineness of 10 μm to obtain early stage water slurry;

C. Add the water-based hydroxyacrylic acid secondary dispersion into the reactor, and at a stirring speed of 800 rpm, add part of the methyl etherified amino resin, water-based epoxy resin, water-based blocked isocyanate curing agent, and Preliminary water slurry, film-forming aids, and thickeners are then stirred for 25 minutes at a stirring speed of 1000 rpm until the materials are uniform, and a water-based dip coating for tape measures is obtained.

Example 4

A. According to the following formula of dip coating for water-based tape measure, weigh each component for later use: 50 parts of water-based hydroxyacrylic acid secondary dispersion, 2 parts of water-based epoxy resin, 8 parts of partially methyl etherified amino resin, 0.1 pH regulator 2 parts of film-forming aid, 0.8 parts of dispersant, 0.2 parts of wetting agent, 0.3 parts of defoaming agent, 2 parts of water-based blocked isocyanate curing agent, 15 parts of deionized water, 23 parts of titanium dioxide, anti-settling and anti-flow 0.6 parts of hanging additives, 0.3 parts of thickener;

The film-forming aid is diethylene glycol butyl ether, the pH regulator is 2-amino-2-methyl-1-propanol, and the dispersant is ammonium salt dispersant;

Comparative example 1

The only difference between this comparative example and Example 1 is that Comparative Example 1 does not contain water-based epoxy resin, and the other component types, component contents, and preparation processes are consistent with Example 1.

Comparative example 2

The only difference between this comparative example and Example 1 is that Comparative Example 2 does not contain a water-based blocked isocyanate curing agent, and the other component types, component contents, and preparation processes are consistent with Example 1.

Comparative example 3

The only difference between this comparative example and Example 1 is that Comparative Example 3 does not contain water-based epoxy resin and water-based blocked isocyanate curing agent, and the other component types, component contents, and preparation processes are consistent with Example 1.

2. Performance test

The water-based tape measure prepared in the above examples and comparative examples is dip-coated with dip coating. The baking temperature is 150-160°C and the baking time is 15-20 minutes. Then the performance of the coating is tested. The performance The test results are shown in Table 1. The gloss, pencil hardness, adhesion, impact strength, flexibility, water resistance, salt spray resistance, acid resistance, and alkali resistance tests were all performed in accordance with the national standard GB/T9756-2018, among which The larger the gloss unit value, the smoother the paint film surface and the better the gloss; the VOC test is obtained by gas chromatography.

Table 1

It can be seen from Table 1 that compared with Example 1, the water-based dip coating for tape measure prepared in Comparative Example 1 does not contain water-based epoxy resin, and its gloss, hardness, salt spray resistance, acid resistance, and alkali resistance all have varying degrees. The water-based dipping coating for tape measure prepared in Comparative Example 2 does not contain a water-based blocked isocyanate curing agent, and its gloss, hardness, water resistance, salt spray resistance, acid resistance, and alkali resistance are greatly reduced. Comparative Example The water-based dip coating for tape measures prepared in 3 does not contain water-based epoxy resin and water-based blocked isocyanate curing agent, and its performance is not much different from the performance of the water-based dip coating for tape measures prepared in Comparative Example 2. From this, it can be seen that a small amount of When water-based epoxy resin is used as an additive alone, it has little impact on the performance of the water-based dipping coating for tape measures. However, when water-based epoxy resin and water-based blocked isocyanate curing agent are added to the coating together, they will synergize with other components. And the synergistic effect enables the coating to maintain good gloss and color retention during baking, and has excellent water resistance, salt spray resistance, acid and alkali resistance.

Claims

A water-based dip coating for measuring tapes, characterized in that it includes the following components by weight: 45-55 parts of water-based hydroxyacrylic secondary dispersion, 1-2 parts of water-based epoxy resin, and 6 parts of partially methyl etherified amino resin -10 parts, pH regulator 0.1-0.5 parts, film-forming aid 2-6 parts, dispersant 0.5-1 part, wetting agent 0.1-0.3 parts, defoaming agent 0.1-0.3 parts, water-based blocked isocyanate curing agent 1-2 parts, 10-20 parts of water, 20-25 parts of titanium dioxide, 0.5-1 part of anti-settling and anti-sag additives, 0.2-0.5 parts of thickener.
A kind of dip coating for water-based tape measure according to claim 1, characterized in that it includes the following components by weight: 50 parts of water-based hydroxyacrylic acid secondary dispersion, 1.5 parts of water-based epoxy resin, partial methyl etherification 8 parts of amino resin, 0.3 parts of pH regulator, 5 parts of film-forming aid, 0.8 parts of dispersant, 0.2 parts of wetting agent, 0.2 parts of defoaming agent, 1.5 parts of water-based blocked isocyanate curing agent, 14 parts of water, titanium dioxide 22 parts, 0.8 parts of anti-settling and anti-sag additives, and 0.4 parts of thickener.
A dip coating for water-based tape measure according to any one of claims 1 to 2, characterized in that the pH regulator is dimethylethanolamine or 2-amino-2-methyl-1-propanol.
A kind of dip coating for water-based tape measure according to any one of claims 1 to 2, characterized in that the film-forming assistant is dipropylene glycol methyl ether, dipropylene glycol butyl ether, propylene glycol butyl ether, diethylene glycol One or more of butyl ether and isobutyl alcohol.
A water-based dip coating for tape measure according to any one of claims 1 to 2, characterized in that the dispersant is a polycarboxylate sodium salt dispersant or an ammonium salt dispersant.
A water-based dip coating for tape measure according to any one of claims 1 to 2, characterized in that the wetting agent is a water-based silicone wetting agent, and the defoaming agent is polyethersiloxane copolymer A physical defoamer, the anti-settling and anti-sag additive is fumed silica, and the thickener is an associative polyurethane thickener.
A kind of preparation method of dip coating for water-based tape measure according to claim 1, is characterized in that, comprises the following steps:

A. According to the proportion of water-based tape measure and dip coating, weigh each component and set aside;

B. Add water to the reactor, and at stirring speed A, add pH regulator, dispersant, wetting agent, defoaming agent, titanium dioxide, anti-settling and anti-sag additives to the reactor in sequence, and stir evenly. Finally, mixture A is obtained, and the early stage water slurry is obtained after grinding mixture A;

C. Add the water-based hydroxyacrylic acid secondary dispersion into the reactor. At stirring speed B, add part of the methyl etherified amino resin, water-based epoxy resin, water-based blocked isocyanate curing agent, and preliminary water slurry to the reactor. , film-forming aids and thickeners, and then stir evenly to obtain a water-based dip coating for tape measures.
A method for preparing dip coating for water-based tape measures according to claim 7, characterized in that the stirring speed A in step B is 500-800rmp, and the pH regulator and dispersant are added to the reactor in sequence. , wetting agent, defoaming agent, titanium dioxide, and anti-settling and anti-sag additives: add pH adjuster, dispersant, wetting agent, defoaming agent, titanium dioxide, and anti-sag additives to the reactor in sequence every 3-8 minutes. Anti-sag additive.
A method for preparing dip coating for water-based tape measures according to claim 7, characterized in that the stirring speed B in step C is 500-800rmp, and part of the methyl etherified amino resin is added to the reactor in sequence. , water-based epoxy resin, water-based blocked isocyanate curing agent, early stage water slurry, film-forming aid, and thickener are added to the reactor in sequence every 8-15 minutes. Part of the methyl etherified amino resin, water-based epoxy resin, and water-based Blocked isocyanate curing agent, early water slurry, film-forming aid, thickener.