A skin-feel ink for glass printing and a method of making the same

Abstract

This invention discloses a skin-feel ink for glass printing and its preparation method. The raw materials of the skin-feel ink, by weight, include: 25-30 parts modified resin; 40-45 parts diluent; 5-10 parts epoxy resin; 5-10 parts curing agent; 2-3 parts polyethylene wax; 2-3 parts matting agent; 1-2 parts elastic powder; and 1-3 parts defoamer. The raw materials of the modified resin, by weight, include: 6-10 parts polyurethane resin; 15-20 parts castor oil-modified polyol; 1.5-3 parts isophorone diisocyanate; 0.05-0.15 parts catalyst; and 7.2-15 parts solvent. The modified resin combines castor oil-modified polyol with polyurethane resin, which is beneficial for improving the stability of the ester groups and hydrolysis resistance, solving the problem of delamination and brittleness of skin-feel inks on glass under long-term humid conditions.

Description

Technical Field

[0001] This application relates to the field of coating composition technology, and more specifically to a skin-feel ink for glass printing and its preparation method. Background Technology

[0002] Skin-feel inks are produced by curing micro-particles on the surface of printed materials to form a micron-level uneven surface. When a finger slides over it, the actual contact area is reduced and the coefficient of friction is changed, thus producing a soft skin-feel that simulates the touch of silk, rubber, leather, human skin, etc.

[0003] Currently, there are two main technical routes for skin-feel treatment of glass surfaces: one is the traditional acid etching process, which uses strong acid to etch glass to form a matte surface. However, this process has drawbacks such as poor environmental performance, high safety risks, rough and dry feel, and poor stain resistance, and it is difficult to achieve a uniform and consistent high-end skin-feel effect. The other is organic coating technology, which forms a functional coating by printing skin-feel ink on the glass surface. This process is environmentally friendly and highly controllable, and has gradually replaced the acid etching process as the mainstream.

[0004] Polyester-based thermoplastic polyurethane (TPU) is widely used as the main resin for skin-feel inks due to its excellent glass adhesion, film-forming properties, and abrasion resistance. However, the TPU molecular backbone contains a large number of easily hydrolyzed ester groups. In high-temperature and high-humidity environments such as the rainy season in southern China and bathroom settings, these ester groups are easily attacked and broken by water molecules, leading to decreased film adhesion and delamination, thus affecting the product's service life. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a skin-feel ink for glass printing, wherein the raw materials comprise, by weight parts: 25-30 parts of modified resin; 40-45 parts diluent; 5-10 parts epoxy resin; 5-10 parts of curing agent; 2-3 parts of polyethylene wax; 2-3 parts matte powder; 1-2 parts of elastic powder; 1-3 parts defoamer; The raw materials for the modified resin include, by weight, the following: 6-10 parts of polyurethane resin; 15-20 parts of castor oil-modified polyol; 1.5-3 parts of isophorone diisocyanate; Catalyst 0.05-0.15 parts; Solvent 7.2-15 parts.

[0006] One embodiment of the present invention addresses its technical problem by employing the following technical solution: the preparation method of the modified resin includes: According to the modified resin formulation, polyurethane resin is dissolved in solvent at 55-60℃, castor oil modified polyol is added and mixed evenly, the temperature is lowered to 40-50℃, and isophorone diisocyanate is slowly added dropwise to polyurethane resin solution under nitrogen protection. Organic bismuth catalyst is added, and the reaction is kept at the temperature for 40-60 minutes to obtain modified resin.

[0007] One embodiment of the present invention uses a technical solution to solve its technical problem: the number average molecular weight of the polyurethane resin is 20,000-35,000 g / mol.

[0008] One embodiment of the present invention employs a technical solution to solve its technical problem: the water content of the castor oil modified polyol is ≤0.05%.

[0009] One embodiment of the present invention uses the following technical solution to solve its technical problem: the diluent is isophorone.

[0010] One embodiment of the present invention uses the following technical solution to solve its technical problem: the solvent is isophorone.

[0011] This application also proposes a method for preparing the aforementioned skin-feel ink for glass printing, comprising: Step 1: According to the formula, put the modified resin and diluent into a container and stir until they are evenly mixed to obtain the first mixture. Step 2: Add epoxy resin, curing agent, polyethylene wax, matting powder, elastic powder and defoamer to the first mixture, and stir evenly to obtain the second mixture; Step 3: Grind the second mixture to obtain skin-feel ink.

[0012] One embodiment of the present invention adopts the following technical solution to solve its technical problem: in step 3, the mixture is repeatedly ground at least twice.

[0013] One embodiment of the present invention adopts a technical solution to solve its technical problem as follows: in step 1, stirring is carried out under the conditions of a rotation speed of 1000-1500 rpm, a temperature of 60-75℃, and normal pressure.

[0014] One embodiment of the present invention adopts the following technical solution to solve its technical problem: in step 2, stirring is carried out under the conditions of 900-1200 rpm, room temperature, and normal pressure.

[0015] This invention utilizes a modified resin obtained by covalently bonding castor oil-modified polyols with polyurethane resin to prepare skin-feel inks. The modified resin, through the bridging effect of isophorone diisocyanate, covalently links the hydrophobic long chains of the castor oil-modified polyols to the polyurethane resin molecular chains. The long-chain hydrophobic fatty acid alkyl groups in the castor oil-modified polyol molecules are uniformly distributed around the polyurethane resin molecules, forming a dense hydrophobic protective layer. This effectively prevents water molecules from penetrating into the paint film, reducing contact between water molecules and ester groups on the polyurethane resin backbone, thus inhibiting ester group hydrolysis and breakage at the source. Simultaneously, the covalent bond structure firmly locks the ester groups of the polyurethane resin within the molecular framework, preventing ester group migration and further enhancing ester group stability. Test results show that the ink prepared by this invention maintains an adhesion grade of 4B-5B after boiling in water at 85°C for 200 hours, while the unmodified polyurethane resin ink exhibits severe delamination under the same conditions.

[0016] During the modification process, isophorone diisocyanate reacts only with the terminal hydroxyl groups of polyurethane resin and castor oil-modified polyol, without damaging the ester groups on the polyurethane resin backbone, thus preserving the bonding ability between the polyurethane resin and the glass surface. Simultaneously, the polar hydroxyl groups in the castor oil-modified polyol molecule can further form hydrogen bonds with the hydroxyl groups on the glass surface, and its hydrophobic long chains can also improve the wetting and spreading properties of the resin on the glass surface, reducing ink shrinkage and curling on the glass surface, indirectly improving the adhesion strength. Test results show that the adhesion between the ink prepared by this invention and glass can reach level 5B.

[0017] Castor oil-modified polyols have a multi-hydroxyl structure. After reacting with isophorone diisocyanate and curing agents, they can increase the overall crosslinking density of the resin and form a dense three-dimensional network structure. This compensates for the problem of soft paint film caused by high castor oil content. The rigidity provided by polyurethane resin and the flexibility provided by castor oil-modified polyols form a good balance, giving the paint film high hardness and wear resistance. Detailed Implementation

[0018] Unless otherwise stated, the terms used in this invention generally have the meanings commonly understood by those skilled in the art.

[0019] The present invention will now be described in further detail with reference to specific embodiments and data. It should be understood that these embodiments are merely illustrative of the invention and are not intended to limit the scope of the invention in any way.

[0020] In the following embodiments, the various processes and methods not described in detail are conventional methods known in the art. Unless otherwise specified, the materials, reagents, apparatus, instruments, equipment, etc., used in the following examples are commercially available.

[0021] In this application, the raw materials for the skin-feel ink used in glass printing, by weight, include: 25-30 parts of modified resin; 40-45 parts of isophorone; 5-10 parts epoxy resin; 5-10 parts of curing agent; 2-3 parts of polyethylene wax; 2-3 parts matte powder; 1-2 parts of elastic powder; 1-3 parts defoamer; The raw materials for the modified resin include, by weight, the following: 6-10 parts of polyurethane resin; 15-20 parts of castor oil-modified polyol; 1.5-3 parts of isophorone diisocyanate; Catalyst 0.05-0.15 parts Isophorone 7.2-15 parts.

[0022] In view of the above, Examples 1-3 of skin-feel inks are proposed. The weight parts of each component of the skin-feel inks in Examples 1-3 are shown in Table 1.

[0023] Table 1

[0024] The weight proportions of each component of the modified resin for the skin-feel inks in Examples 1-3 are shown in Table 2.

[0025] Table 2

[0026] The raw material sources for the skin-feel inks used in glass printing in this application are shown in Table 3.

[0027] Table 3

[0028] The preparation method of the skin-feel ink in Examples 1-3 above includes: Step 1: According to the modified resin formula, dissolve the polyurethane resin in a solvent at 55-60℃, add castor oil-modified polyol and mix evenly. Cool down to 40-50℃, and under nitrogen protection, slowly add isophorone diisocyanate to the polyurethane resin solution. Add 0.05-0.15 parts of organic bismuth catalyst and keep the reaction at this temperature for 40-60 minutes to obtain the modified resin. According to the skin-feel ink formula, put the modified resin and diluent into a container and stir until evenly mixed at a speed of 1000-1500 rpm, a temperature of 60-75℃, and normal pressure to obtain the first mixture. Among them, castor oil-modified polyols undergo vacuum dehydration treatment, with a water content not exceeding 0.05%; Step 2: Add epoxy resin, curing agent, polyethylene wax, matting powder, elastic powder and defoamer to the first mixture, and stir evenly under the conditions of 900-1200 rpm, room temperature and normal pressure to obtain the second mixture; Step 3: Grind the second mixture twice using a three-roll mill to obtain skin-feel ink.

[0029] To address the above, Comparative Example 1 and Comparative Example 2 of skin-feel inks are proposed.

[0030] The raw materials of the skin-feel ink in Comparative Example 1, by weight, include: 28 parts of polyurethane resin; 8 parts epoxy resin; 42 parts of diluent; 7 parts curing agent; 2.5 parts of polyethylene wax; 2.5 parts matte powder; 1.5 parts elastic powder; 1.5 parts of defoamer.

[0031] The preparation method of the skin-feel ink in Comparative Example 1 is as follows: Step 1: According to the formula amount of skin-feel ink, put polyurethane resin and diluent into a container, and stir until they are evenly mixed under the conditions of 1000-1500 rpm, 60-75℃ and normal pressure to obtain the first mixture. Step 2: Add epoxy resin, curing agent, polyethylene wax, matting powder, elastic powder and defoamer to the first mixture, and stir evenly under the conditions of 900-1200 rpm, room temperature and normal pressure to obtain the second mixture; Step 3: Grind the second mixture twice using a three-roll mill to obtain skin-feel ink.

[0032] The skin-feel inks prepared in Examples 1-3 were screen-printed onto a clean tempered glass surface using a 150-200 mesh screen. After being surface-dried at room temperature for 5 minutes, they were baked at 175-185°C for 6-7 minutes and left to stand for 24 hours.

[0033] The raw material composition of the skin-feel ink in Comparative Example 2 is the same as that in Example 1. The modified resin is prepared by dissolving the polyurethane resin in a solvent, adding castor oil-modified polyol, and mixing thoroughly to obtain the modified resin of Comparative Example 2. The skin-feel ink in Comparative Example 2 is prepared by: Step 1: According to the formula amount of skin-feel ink, put the modified resin and diluent into a container, and stir until they are evenly mixed under the conditions of 1000-1500 rpm, 60-75℃ and normal pressure to obtain the first mixture. Among them, castor oil-modified polyols undergo vacuum dehydration treatment, with a water content not exceeding 0.05%; Step 2: Add epoxy resin, curing agent, polyethylene wax, matting powder, elastic powder and defoamer to the first mixture, and stir evenly under the conditions of 900-1200 rpm, room temperature and normal pressure to obtain the second mixture; Step 3: Grind the second mixture twice using a three-roll mill to obtain skin-feel ink.

[0034] The skin-feel inks prepared in Examples 1-3 and Comparative Examples 1-2 were screen-printed onto a clean tempered glass surface using a 150-200 mesh screen. After being surface-dried at room temperature for 5 minutes, they were baked at 175-185°C for 6-7 minutes and left to stand for 24 hours before performance testing. The test items and results are shown in Table 4.

[0035] Table 4

[0036] In Example 3, the amount of epoxy resin was reduced to 5 parts, and the rigid component was reduced; at the same time, the amount of castor oil modified polyol was increased to 20 parts, and the proportion of flexible segments was increased, resulting in a slight decrease in the hardness of the paint film. In addition, the high amount of castor oil led to a slight decrease in the crosslinking density of the paint film. A small amount of water molecules could penetrate into the interior of the paint film, causing a decrease in wear resistance under slight adhesion.

[0037] In Comparative Example 1, the unmodified polyurethane itself has excellent glass adhesion, but lacks hydrolysis protection. Under high temperature and high humidity conditions, water molecules directly attack the ester groups, causing the molecular chains to break. The cohesion of the paint film drops sharply, resulting in large-area delamination. It also has poor abrasion resistance and is prone to obvious scratches after being wiped with steel wool.

[0038] In Comparative Example 2, the polyurethane resin and castor oil modified polyol were physically blended, resulting in insufficient crosslinking density and phase separation, which led to defects in the paint film and a significant decrease in hardness and abrasion resistance. Furthermore, microphase separation was prone to occur, with uneven distribution of castor oil polyol and polyurethane resin, resulting in decreased interfacial bonding. During long-term storage, slight delamination was likely to occur, leading to edge delamination, decreased abrasion resistance, and easy damage to the paint film surface by friction, resulting in loss of gloss and obvious scratches.

[0039] Of course, the present invention is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications and substitutions are included within the scope defined by the claims of this application.

Claims

1. A skin-feel ink for glass printing, characterized in that, The raw materials, by weight, include: 25-30 parts of modified resin; 40-45 parts diluent; 5-10 parts epoxy resin; 5-10 parts of curing agent; 2-3 parts of polyethylene wax; 2-3 parts matte powder; 1-2 parts of elastic powder; 1-3 parts defoamer; The raw materials for the modified resin include, by weight, the following: 6-10 parts of polyurethane resin; 15-20 parts of castor oil-modified polyol; 1.5-3 parts of isophorone diisocyanate; Catalyst 0.05-0.15 parts; Solvent 7.2-15 parts.

2. The skin-feel ink for glass printing according to claim 1, characterized in that, The method for preparing the modified resin includes: According to the modified resin formulation, polyurethane resin is dissolved in solvent at 55-60℃, castor oil modified polyol is added and mixed evenly, the temperature is lowered to 40-50℃, and isophorone diisocyanate is slowly added dropwise to polyurethane resin solution under nitrogen protection. Organic bismuth catalyst is added, and the reaction is kept at the temperature for 40-60 minutes to obtain modified resin.

3. The skin-feel ink for glass printing according to claim 1, characterized in that, The number average molecular weight of the polyurethane resin is 20,000-35,000 g / mol.

4. The skin-feel ink for glass printing according to claim 1, characterized in that, The castor oil-modified polyol has a water content of ≤0.05%.

5. The skin-feel ink for glass printing according to claim 1, characterized in that, The diluent is isophorone.

6. The skin-feel ink for glass printing according to claim 1, characterized in that, The solvent is isophorone.

7. A method for preparing a skin-feel ink for glass printing as described in any one of claims 1-6, characterized in that, include: Step 1: According to the formula, put the modified resin and diluent into a container and stir until they are evenly mixed to obtain the first mixture. Step 2: Add epoxy resin, curing agent, polyethylene wax, matting powder, elastic powder and defoamer to the first mixture, and stir evenly to obtain the second mixture; Step 3: Grind the second mixture to obtain skin-feel ink.

8. The method for preparing the skin-feel ink for glass printing according to claim 7, characterized in that, Step 3 involves grinding the mixture at least twice.

9. The method for preparing the skin-feel ink for glass printing according to claim 7, characterized in that, In step 1, the mixture is stirred at a speed of 1000-1500 rpm, a temperature of 60-75℃, and at normal pressure.

10. The method for preparing the skin-feel ink for glass printing according to claim 7, characterized in that, In step 2, the mixture is stirred at a speed of 900-1200 rpm, at room temperature and pressure.

Images